可攜式印表機列印模組設計

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(1)國立交通大學機械工程學系. 碩士論文. 可攜式印表機列印模組設計 Design of Print Module on Mobile Printer. 研究生：吳敏全指導教授：曾錦煥教授. 中華民國九十四年六月.

(2) 可攜式印表機列印模組設計. Design of Print Module on Mobile Printer. 研究生：吳敏全. Student: Min-Chuan Wu. 指導教授：曾錦煥教授. Advisor: Ching-Huan Tseng. 國立交通大學機械工程研究所碩士論文. A Thesis Submitted to Institute of Mechanical Engineering College of Engineering National Chiao Tung University in Partial Fulfillment of the Requirements for the Degree of Master in Mechanical Engineering. June 2005 Hsinchu, Taiwan, Republic of China. 中華民國九十四年六月.

(3) 可攜式印表機列印模組設計. 研究生:吳敏全. 指導教授:曾錦煥. 國立交通大學機械工程研究所. 摘要. 本論文主要在研究使用熱轉印技術的可攜式印表機。近年來因為數位相機的普及，所以相片印表機的需求也日益增多。加上行動通訊的發達，市面上有愈來愈多的行動輸入裝置，例如手機或 PDA 等。然而小型印表機此種行動的輸出裝置，相對於輸入裝置則相當地少。現今愈來愈多廠商開始投入可攜式印表機的研發，由此看來可攜式印表機是未來直得發展的方向之一。. 當設計可攜式印表機時，印表機體積及列印時間是兩個主要可攜式印表機的消費者使用需求。經由市場商品調查及專利分析後，可確定較符合以上設計需求的規格。在本篇論文中會提出幾個新的概念，這些概念將藉由一些機構的設計來減少使用的馬達，進而達到以上兩個需求。本文最後提供一個創新的列印模組機構設計，分析其此機構之可行性，並藉由原型的製作將此概念設計具體化實施。. i.

(4) Design of Print Module on Mobile Printer. Student: Min-Chuan Wu. Advisor: Ching-Huan Tseng. Institute of Mechanical Engineering National Chiao Tung University. ABSTRACT. This study focuses on a mobile printer using thermal transfer printing technology.. In. recent years, since digital cameras are more and more common, the requirement of photo printer is increasing.. In addition, because of the development of mobile communication,. there are more and more mobile input devices such as PDA and cell phone on the market. However, the mobile output devices, such as small printer, are much fewer than input devices. Now there are more and more companies beginning to develop mobile printers.. Therefore, it. is worth to develop in the future.. When design mobile printer, size and printing time are the two main requirements of mobile printer for users.. After product research and patent analysis, the objectives which are. satisfied the requirements above can be confirmed. In the thesis, several new concepts are proposed, and these concepts use some mechanism design to reduce the number of motors used for achieving these two requirements. mechanism design of the print module.. Finally, the thesis proposes one innovative. Analyze the feasibility of the mechanism and. embody the concept by prototype.. ii.

(5) TABLE OF CONTENTS 摘要 .............................................................................................................................................i ABSTRACT ...............................................................................................................................ii TABLE OF CONTENTS...........................................................................................................iii LIST OF TABLES ......................................................................................................................v LIST OF FIGURES ...................................................................................................................vi Chapter 1 Introduction................................................................................................................1 1.1 Printers..........................................................................................................................1 1.2 Motivation ....................................................................................................................1 1.3 Thesis Organization ...................................................................................................... 3 Chapter 2 Literature Reviews .....................................................................................................5 2.1 Printing Technologies ...................................................................................................5 2.1.1 Inkjet Print .........................................................................................................5 2.1.2 Laser Print .........................................................................................................6 2.1.3 Dye Diffusion Thermal Transfer .......................................................................7 2.1.4 Thermal Wax Transfer .......................................................................................9 2.1.5 Variable Dot Thermal Wax Transfer ..................................................................9 2.1.6 Continuous Tone and Half Tone ......................................................................10 2.1.7 Comparison with These Printing Technologies...............................................10 2.2 Marketing Research.................................................................................................... 11 2.2.1 CANON ...........................................................................................................12 2.2.2 ALPS................................................................................................................12 2.2.3 Other Companies .............................................................................................12 2.3 The Configuration of Thermal Transfer Printer..........................................................13 2.3.1 Print Head Module ..........................................................................................13 2.3.2 Ink Ribbon Module..........................................................................................13 2.3.3 Paper Feeding Module.....................................................................................14 2.4 Remarks ......................................................................................................................14 Chapter 3 Design Method and Requirements...........................................................................26 3.1 TRIZ ...........................................................................................................................26 3.1.1 Introduction of TRIZ .......................................................................................26 3.1.2 The Foundation of TRIZ..................................................................................27 3.2 Requirements ..............................................................................................................30 3.2.1 Size ..................................................................................................................31 3.2.2 Printing time ....................................................................................................32 3.3 Objectives ...................................................................................................................33 3.4 Remarks ......................................................................................................................33 iii.

(6) Chapter 4 Conceptual Design ...................................................................................................36 4.1 Present Designs ..........................................................................................................36 4.1.1 Steps of Printing Process in ALPS ..................................................................37 4.2 Conceptual Designs ....................................................................................................38 4.2.1 Concept 1.........................................................................................................38 4.2.2 Concept 2.........................................................................................................40 4.2.3 Concept 3.........................................................................................................41 4.2.4 Concept 4.........................................................................................................43 4.2.5 Concept 5.........................................................................................................44 4.2.6 Comparison......................................................................................................46 4.3 Remarks ......................................................................................................................47 Chapter 5 Embodiment Design and Prototype .........................................................................73 5.1 Embodiment ...............................................................................................................73 5.1.1 Printer Frame ...................................................................................................73 5.1.2 Thermal Print Head Module ............................................................................74 5.1.3 Ink Ribbon Cassette.........................................................................................75 5.1.4 Power Transmitting Mechanism......................................................................75 5.1.5 Three Printing Steps ........................................................................................76 5.2 Prototype.....................................................................................................................76 5.2.1 Gear .................................................................................................................77 5.2.2 Manufacture.....................................................................................................77 5.2.3 Assembly .........................................................................................................77 5.3 Remarks ......................................................................................................................78 Chapter 6 Analysis....................................................................................................................98 6.1 Weight.........................................................................................................................98 6.2 Displacement of Paper and Ribbon ............................................................................98 6.3 Motor ..........................................................................................................................99 6.3.1 Pulse Rate of Stepping Motor..........................................................................99 6.3.2 Torque ............................................................................................................100 6.4 Action Analysis.........................................................................................................103 6.5 Remarks ....................................................................................................................104 Chapter 7 Conclusions............................................................................................................ 110 7.1 Conclusions .............................................................................................................. 110 7.2 Future Works ............................................................................................................ 111 References .............................................................................................................................. 113. iv.

(7) LIST OF TABLES. Table 2.1 Comparison of thermal printing technologies ..........................................................21 Table 2.2 Canon’s products ......................................................................................................22 Table 2.3 Products of ALPS .....................................................................................................23 Table 2.4 Products of other companies.....................................................................................24 Table 3.1 39 features of system ................................................................................................34 Table 3.2 40 principles..............................................................................................................35 Table 4.1 Part of contradiction matrix ......................................................................................49 Table 4.2 Conceptual design comparison .................................................................................49 Table 5.1 Gears used in prototype ............................................................................................ 79 Table 6.1 The weights of print module...................................................................................105 Table 6.2 Specification of thermal print head.........................................................................105 Table 6.3 Simulation result of rotation angle after deceleration.............................................106 Table 7.1 Comparison............................................................................................................. 112. v.

(8) LIST OF FIGURES Fig.1.1 The trend of sales volume of photo printer [4]...............................................................4 Fig.2.1 Inkjet - Thermal bubble [5] ..........................................................................................15 Fig.2.2 Inkjet – Piezoelectric [5] ..............................................................................................15 Fig.2.3 Basic laser printer components [6]...............................................................................16 Fig.2.4 The path of paper in laser printer .................................................................................16 Fig.2.5 Dye diffusion thermal transfer [7]................................................................................17 Fig.2.6 Step1 – Ribbon search in dye diffusion thermal transfer .............................................18 Fig.2.7 Step2 – Paper feed in dye diffusion thermal transfer ...................................................18 Fig.2.8 Step3 – Print in dye diffusion thermal transfer ............................................................18 Fig.2.9 Thermal wax transfer [8]..............................................................................................19 Fig.2.10 Variable dot thermal wax transfer [8].........................................................................19 Fig.2.11 Dithering technique ....................................................................................................20 Fig.2.12 Fig. 2.12 Continuous tone and half tone [7]...............................................................20 Fig.2.13 Portion of 300 dpi image printed on thermal printing technologies [8].....................21 Fig.2.14 Subsystem of thermal printer .....................................................................................25 Fig. 4.1 Product of Olympus ....................................................................................................50 Fig. 4.2 The structure of Olympus product [12].......................................................................50 Fig. 4.3 Products of ALPS ........................................................................................................51 Fig. 4.4 Structure of ALPS product [13] ..................................................................................51 Fig. 4.5 Cam gear in ALPS design ...........................................................................................52 Fig. 4.6 The design of ALPS ....................................................................................................52 Fig. 4.7 Step 1- Ribbon Searching of ALPS.............................................................................53 Fig. 4.8 Step 1 to Step 2 of ALPS.............................................................................................53 Fig. 4.9 Step 2- Feeding Paper Forward of ALPS ....................................................................53 Fig. 4.10 Step 3- Feeding Paper Backward of ALPS ...............................................................54 Fig. 4.11 Step 4- Printing of ALPS...........................................................................................54 Fig. 4.12 3D view of concept 1 ................................................................................................55 Fig. 4.13 Section 1 of concept 1 ...............................................................................................55 Fig. 4.14 Section 2 of concept 1 ...............................................................................................55 Fig. 4.15 Step 1 – Ribbon Searching of concept 1 ...................................................................56 Fig. 4.16 Step 2 – Paper Feeding of concept 1 .........................................................................56 Fig. 4.17 Step 3 – Printing of concept 1 ...................................................................................56 Fig. 4.18 3D view of concept 2 ................................................................................................57 Fig. 4.19 Section 1 of concept 2 ...............................................................................................58 Fig. 4.20 Section 2 of concept 2 ...............................................................................................58 Fig. 4.21 Section 3 of concept 2 ...............................................................................................58 vi.

(9) Fig. 4.22 Step 1 – Ribbon Searching of concept 2 ...................................................................59 Fig. 4.23 Step 2 – Paper Feeding of concept 2 .........................................................................59 Fig. 4.24 Step 3 – Printing of concept 2 ...................................................................................59 Fig. 4.25 3D view of concept 3 ................................................................................................60 Fig. 4.26 Section 1 of concept 3 ...............................................................................................61 Fig. 4.27 Section 2 of concept 3 ...............................................................................................61 Fig. 4.28 Section 3 of concept 3 ...............................................................................................61 Fig. 4.29 Step 1 – Ribbon Searching of concept 3 ...................................................................62 Fig. 4.30 Step 2 – Paper Feeding of concept 3 .........................................................................62 Fig. 4.31 Step 3 - Print Head Compressing of concept 3 .........................................................63 Fig. 4.32 Step 4 – Printing of concept 3 ...................................................................................63 Fig. 4.33 3D view of concept 4 ................................................................................................64 Fig. 4.34 Section 1 of concept 4 ...............................................................................................65 Fig. 4.35 Section 2 of concept 4 ...............................................................................................65 Fig. 4.36 State 1 of section 1 of concept 4 ...............................................................................66 Fig. 4.37 State 2 of section 1 of concept 4 ...............................................................................66 Fig. 4.38 State 3 of section 1 of concept 4 ...............................................................................67 Fig. 4.39 State 4 of section 1 of concept 4 ...............................................................................67 Fig. 4.40 Step 1 – Ribbon Searching of concept 4 ...................................................................68 Fig. 4.41 Step 2 – Paper Feeding of concept 4 .........................................................................68 Fig. 4.42 Step 3 – Printing of concept 4 ...................................................................................68 Fig. 4.43 3D view of concept 5 ................................................................................................69 Fig. 4.44 Section 1 of concept 5 ...............................................................................................70 Fig. 4.45 Section 2 of concept 5 ...............................................................................................70 Fig. 4.46 Section 3 of concept 5 ...............................................................................................70 Fig. 4.47 Way of step-changing and power output of concept 5 ..............................................71 Fig. 4.48 Step 1 – Ribbon Searching of concept 5 ...................................................................71 Fig. 4.49 Step 2 – Paper Feeding of concept 5 .........................................................................72 Fig. 4.50 Step 3 – Printing of concept 5 ...................................................................................72 Fig. 5.1 The printer design........................................................................................................80 Fig. 5.2 The printer design........................................................................................................80 Fig. 5.3 (a) Front view (b) Top view of the whole print module..............................................81 Fig. 5.4 Printer frame................................................................................................................82 Fig. 5.5 Upper cover of printer .................................................................................................82 Fig. 5.6 Design of print head module .......................................................................................83 Fig. 5.7 Design of print head assembly ....................................................................................83 Fig. 5.8 State of print head released .........................................................................................84 Fig. 5.9 State 1 of print head pressed .......................................................................................84 Fig. 5.10 State 2 of print head pressed .....................................................................................85 vii.

(10) Fig. 5.11 Ink ribbon cassette.....................................................................................................85 Fig. 5.12 Side view of ink ribbon cassette................................................................................86 Fig. 5.13 Gear train of printer design .......................................................................................86 Fig. 5.14 Section 1 of gear train ...............................................................................................87 Fig. 5.15 Section 2 of gear train ...............................................................................................87 Fig. 5.16 Cam gear in printer design ........................................................................................87 Fig. 5.17 Gear train 3A to ribbon roller....................................................................................88 Fig. 5.18 Gear train 3B to capstan roller ..................................................................................88 Fig. 5.19 Step 1 – Ribbon Searching ........................................................................................89 Fig. 5.20 Step 2 – Paper Feeding..............................................................................................89 Fig. 5.21 Step 3 – Printing........................................................................................................89 Fig. 5.22 Drawing 1 (One side of printer frame)......................................................................90 Fig. 5.23 Drawing 2 (Support plate for gear train)................................................................... 91 Fig. 5.24 Drawing 3 (Other components).................................................................................92 Fig. 5.25 Drawing 4 (Power switch plates) ..............................................................................93 Fig. 5.26 Photo of the components ...........................................................................................94 Fig. 5.27 Photo of motor support plate.....................................................................................94 Fig. 5.28 Photo of two acrylic plastic plates ............................................................................95 Fig. 5.29 Section 1 of gear train ...............................................................................................96 Fig. 5.30 Section 2 of gear train ...............................................................................................96 Fig. 5.31 Section 3A and 3B of gear train ................................................................................ 96 Fig. 5.32 (a) Front view (b) Top view of the whole prototype .................................................97 Fig. 6.1 The position of print head module ............................................................................107 Fig. 6.2 The simulation model................................................................................................107 Fig. 6.3 Simulation result of print head module .....................................................................108 Fig. 6.4 The two cases of planet gear .....................................................................................109 Fig. 6.5 Way to increase the resistance of planet gear............................................................ 109. viii.

(11) Chapter 1 Introduction. 1.1 Printers. Printer is one kind of output devices for computers.. It can transfer the information in. computer or the images in digital camera to documents or photos for people to read or preserve. Now there are many kinds of printing technologies, such as inkjet and laser, etc. In addition, the developing directions of printer are various. Besides the developments of higher image quality printing and the faster printing speed for general printers, mobile printer is also one important direction of printer developments in the future [1].. 1.2 Motivation. Mobile communication is vastly growing recently.. Obviously the information input. devices, such as digital camera and cell phone, are more and more common [2]. Because the digital cameras are popular, traditional photograph is superseded by digital image gradually. Therefore, users need a display device to view the images.. However, it still can not take the. place of traditional photograph completely because people are used to view images by photographs for a long time [3].. As shown in Fig.1.1, the sales volume of photo printer is. growing year by year. Therefore, users can print the images by themselves instead of go to the photograph store.. However, the development of output end of the mobile information transmission is slower than input devices.. The proper printer with lightweight, compact, convenient, and. mobile characteristics is harder to seem than general printer on market. 1. At present, there are.

(12) more and more companies noticing this market and more mobile printers are made.. Because the mobile communication is more and more popular, the demand of such a mobile printer is brewing and will be booming very soon. Therefore, people can carry a mobile printer with digital cameras.. After take pictures by digital cameras, people can just. print the photos outside to share the enjoyment right away.. As mentioned above, there are several popular full color printing technologies which can implement the photo printing purpose.. However, when considering lightweight, lower. power consumption and simple configuration among those technologies, thermal transfer printing technologies are applicable to reach the aim most.. The reason will be illustrated in. Chapter 2. Therefore, thermal transfer printing technologies are taken as the technology used in the print module of mobile printer in the thesis.. Most of the printers are very big and can just be put on the desk at home or office. Producing a mobile printer is harder than a printer for home or office use because the element size on mobile printer is smaller and it is necessary to reduce the number of motors for size reduction. Most of the motors in thermal transfer printer are used on the print module to drive the paper, ink ribbon and thermal print head.. Therefore, the problem, how to reduce. the number of motors in print module, has to be solved.. According to the reasons above, the purpose of this research is to reduce the number of motors used in print module and provide a new patentable design of print module on the mobile printer.. 2.

(13) 1.3 Thesis Organization. In this study, Chapter 2 is the literatures review which includes brief introduction of general printing technologies, the comparison of these printing technologies, marketing research and the configuration of thermal transfer printer.. Chapter 3 introduces the. requirements and the theory of “TRIZ” when designing the print module on mobile printer. Conceptual designs are introduced in Chapter 4. Chapter 5 presents the embodiment design of the chosen concept and the prototype. test the feasibility.. Chapter 6 shows the analysis of the final design to. Chapter 7 is conclusions and works.. 3.

(14) Thousands 90000 80000 70000 60000 50000 40000 30000 20000 10000 0 1999. 2000. 2001. 2002. 2003. 2004. 2005. Year. Fig.1.1 The trend of sales volume of photo printer [4]. 4. 2006.

(15) Chapter 2 Literature Reviews. 2.1 Printing Technologies. Now there are many kinds of printing technologies on market and the way to form images on paper is different to each other. Here are some introductions about these printing technologies.. 2.1.1 Inkjet Print. Inkjet is the most common printing technology now. thermal bubble and piezoelectric, on inkjet printer.. There are two different types,. Different types of inkjet printers form. droplets of ink in different ways.. Thermal bubble - Used by manufacturers such as Canon and Hewlett Packard, this method is commonly referred to as bubble jet.. As shown in Fig.2.1, in a thermal inkjet. printer, tiny resistors create heat, and this heat vaporizes ink to create a bubble. As the bubble expands, some of the ink is pushed out of a nozzle onto the paper. When the bubble pops (collapses), a vacuum is created.. This pulls more ink into the print head from the. cartridge. A typical bubble jet print head has 300 or 600 tiny nozzles, and all of them can fire a droplet simultaneously.. Piezoelectric - Patented by Epson, this technology uses piezo crystals.. As shown in. Fig.2.2, a crystal is located at the back of the ink reservoir of each nozzle. The crystal 5.

(16) receives a tiny electric charge that causes it to vibrate.. When the crystal vibrates inward, it. forces a tiny amount of ink out of the nozzle. When it vibrates out, it pulls some more ink into the reservoir to replace the ink sprayed out [5].. 2.1.2 Laser Print. The process of forming images in laser printer can be divided into six steps.. Step 1: Drum preparation - In preparation for printing, the drum must be cleaned to remove any traces of previous pages.. First, a rubber blade wipes the excess toner from the. drum, and then erase lamps (in older models) or a charged drum (in newer models) electrostatically clean it by neutralizing residual electrical charges on it.. Step 2: Drum writing - The data in the printer’s memory is written to the drum using a laser.. Rather than writing it with ink or toner, however, it writes by shining a very precise. laser on the photosensitive drum in certain spots, changing the electrical charge in those spots. As the drum cylinder rotates past the laser, it sweeps across the surface, turning on and off to neutralize certain areas to about -100V.. These neutralized areas will be the spots where. toner adheres to the drum later in the process and then transfers to the paper.. Step 3: Paper feed - Feed rollers draw the paper into the printer from the paper tray. Registration rollers hold the paper until it’s time for it to be released.. Step 4: Toner pickup - Steps 3 and 4 occur more or less simultaneously. As the paper is being drawn in, the toner is being applied to the drum.. 6.

(17) The toner cartridge contains a rotating, magnetic, metal-developing cylinder, a toner reservoir, and a height control mechanism that limits the amount of toner the cylinder can pick up at a time. Toner consists of plastic resin particles (the particles that melt to produce the image on paper) and iron oxide (the particles that are affected by magnetic attraction and electrical charges).. The toner’s metal particles adhere to the magnetic cylinder, and the. cylinder presents the toner to the drum as it passes by.. Step 5: Toner transfer to paper - At this point, the image exists on the drum, complete with toner. As the paper feeds into the printer, the transfer corona applies a positive charge to the paper.. When the paper passes by the drum, the -100V charged toner on the drum. jumps off onto the positively charged paper. Then, the paper runs past a static charge eliminator, which is a row of teeth with a negative charge that reduces the paper’s highly positive charge.. Step 6: Fusing the toner to the paper - The image is on the paper, but it’s not secure there; it’s just loose toner held in place by gravity and a weak electrostatic charge. For permanent application, it must be fused.. Fusing is basically melting the toner’s particles so. that they stick, or fuse, to the fibers in the paper.. Fig.2.3 and Fig.2.4 show the components of laser printer and the paper path while printing [6].. 2.1.3 Dye Diffusion Thermal Transfer. Dye diffusion thermal transfer (D2T2) is one kind of technology using thermal sensitive ink for printing.. There are some aliases such as dye sublimation or thermal dye transfer. 7.

(18) As shown in Fig.2.5, while printing, paper rollers and ink ribbon rollers rotate, and the line velocity of the paper is the same with ink ribbon. head is pressed against the platen roller.. At the same time, the thermal print. The ribbon with yellow, magenta, cyan dyes and an. overcoating will sublimate to vapor because of the heat generated from the thermal print head, and then be absorbed by the coating on the special paper step by step. Since each heating element on thermal print head can generate 256 gradients of heat and there are three different colors of dye, D2T2 can print a colorful image with 16 million colors. Besides, compared with other print technologies, there is an overcoating on the photo printed by D2T2. Therefore, the photo preservation is easier and there is a better resistance to ultraviolet, water, or dirt. There are three steps during the printing process [7].. Step 1: Ribbon Searching – Before printing, the ribbon must be located at the initial position for the whole printing.. As shown in Fig.2.6, the paper is at the opposite side of the. printer at this time. The ribbon rollers rotate to search the initial position of the ribbon. During this step, the tension of the ribbon is in a loose state.. Step 2: Paper Feeding – As shown in Fig.2.7, the paper is drawn into printer by capstan roller and passes through the platen roller to the other side. At this time, the ribbon rollers are fixed.. Step 3: Printing – As shown in Fig.2.8, when the ribbon is ready for printing, thermal print head will be pressed against the platen roller and ink ribbon will attach to the paper on the platen roller.. Then ink ribbon rollers and capstan roller begin rotating simultaneously in. the same line velocity to form monochromatic image on the paper.. After the monochromatic image is formed, the thermal print head will be raised and the 8.

(19) paper will be rewound to the state before printing for the next color printing until all the dyes of yellow, magenta, cyan and the coating are printed on the paper.. 2.1.4 Thermal Wax Transfer. Thermal wax transfer is also called thermal transfer.. It typically consists of a donor, a. receiver and a thermal print head. In the case the thermal print head has a fixed energy level and results in an approximately fixed dot size and constant density. This system is shown in Fig.2.9.. Thermal wax transfer printers operate with the same steps as dye diffusion thermal transfer printers to form images on papers and the configuration is almost the same. Thermal wax transfer printers use cyan, magenta, and yellow wax type of pigments instead of dye to produce images. Thermal wax transfer has a binary process. It means that for a given location on a page, either a lot of pigments are deposited or not. And various dithering techniques are used in order to create half tone level [8].. 2.1.5 Variable Dot Thermal Wax Transfer. The working principle of variable dot thermal wax transfer is almost the same with thermal wax transfer. The difference is that in variable dot thermal wax transfer, the thermal print head is able to modulate energy. This results in a dot with a roughly fixed density but varying dot area and is shown in Fig.2.10. Consequently, dithering techniques used for traditional fixed dot size thermal transfer printing are not needed.. Therefore, variable dot. thermal wax transfer can modulate the dot size to form the gradation [8].. 9.

(20) 2.1.6 Continuous Tone and Half Tone. As shown in Fig.2.11 and Fig.2.12, for example, while generating a gradation from black to white, the printer with continuous tone can form the continuous color gradation because each dot has its own fullness of color.. But in the printer with half tone, each dot has only. one kind of color fullness, and it must use the dithering technique which is that there are lots of dots close to each other in a small area, and changing the density of dots to simulate the gradation. Therefore, the image quality of half tone can not reach the quality of continuous tone, especially when enlarging the photos.. For this reason, more dots per inch are needed in the printer using half tone to form clear images.. But using continuous tone, 300 dots per inch is enough to form clear images.. above printing technologies, only dye diffusion thermal transfer is continuous tone.. In. Variable. dot thermal wax transfer is close to continuous tone, and the others are half tone [7].. 2.1.7 Comparison with These Printing Technologies. Compared with inkjet, laser, dye diffusion thermal transfer, thermal wax transfer and variable dot thermal wax transfer, laser and inkjet are not fit for the requirements of mobile printer because the configuration of the laser printer is more complicated and inkjet needs larger space for the print head movement.. Therefore, dye diffusion thermal transfer, thermal. wax transfer and variable dot thermal wax transfer are better to use on the mobile printer.. Table 2.1 is the comparison of these three thermal printing technologies.. In. Preservation, all the three technologies are good because there is a coating layer printed on the photos, and the configurations of the three technologies are almost the same. 10. In color.

(21) performance, dye diffusion thermal transfer is the best because the way to form color gradation is continuous tone, and the performance of thermal wax transfer is inferior in the same dpi.. As shown in Fig.2.13, the figures from left to right are printed individually on. thermal wax transfer, variable dot thermal wax transfer and dye diffusion thermal transfer.. In continuous printing, thermal wax transfer and variable dot thermal wax transfer are better than dye diffusion thermal transfer because less energy is required to melt wax than to diffuse dye.. Therefore, the thermal print head in dye diffusion thermal transfer may overheat. while continuous printing.. For the same reason, in power consumption, dye diffusion. thermal transfer is higher than the others. Consequently, with the same power, thermal wax transfer and variable dot thermal wax transfer can print more pieces than dye diffusion thermal transfer.. Finally, in the cost, because the pigment (wax) and the receiver (paper) of thermal wax transfer or variable dot thermal wax transfer are less expensive than the corresponding things of dye diffusion thermal transfer, the cost of dye diffusion thermal transfer is higher.. According to the reasons above, variable dot thermal wax transfer and dye diffusion thermal transfer are the better printing technologies and both of them can be used in the future print module design because of the same configuration.. 2.2 Marketing Research. There are many kinds and many types of printers on market.. Here is an introduction. about the mobile printers whose weight is about 1Kg or lower than 1 Kg.. 11.

(22) 2.2.1 CANON. Table 2.2 lists the four mobile printers of CANON on market. four products are almost the same.. The specifications of. The most differences between them are the print paper. size and whether it can use the battery or not.. 2.2.2 ALPS. There are three products of ALPS, PTMTL28, PTMTL27 and PTMTL14. (In Table 2.3) They are just the print modules.. It seems that ALPS only produce the print module, not the. whole printer.. 2.2.3 Other Companies. As shown in Table 2.4, there are also other mobile printers made by other companies, such as SONY, PANASONIC, KODAK and FUJIFILM, etc. PANASONIC have one product.. Both of SONY and. And there are several mobile printers of KODAK, here list. only one product because other products just support for different kinds of digital cameras. Besides, the mobile printer of FUJIFILM can print the photos taken by the camera on mobile phones.. Users can use IrDA to send the photos from cell phone to the printer directly.. From Table 2.2 to Table 2.4, there are two things worth to notice. mobile printers use dye diffusion thermal transfer.. First, most of the. Only the products of ALPS and. PANASONIC SV-20 use variable dot thermal wax transfer.. Second, almost all the mobile. printers are made by the companies which also made digital cameras.. It means that these. companies have also paid attention to the market of image output, not only the market of 12.

(23) image input such as cameras.. 2.3 The Configuration of Thermal Transfer Printer. As shown in Fig.2.14, a thermal transfer printer can separate into five subsystems, print module, paper feed, power supply, frame, control unit and user interface. Besides the control unit and paper feed, the main subsystem for the printing is the print module.. It includes. paper feed, thermal print head and ink ribbon modules.. 2.3.1 Print Head Module. Print head module consists of thermal print head, platen roller, transmission means, motor, spring, platen roller and cooling means. The thermal print head is separated from the platen roller normally.. While printing, the motor will rotate and the thermal print head will. be pressed with the platen roller by transmission means.. The spring will make the pressure. uniform.. 2.3.2 Ink Ribbon Module. Ink ribbon module consists of ink ribbon, ink ribbon cassette, tension limit means, motor and roller. While printing, the rollers will wind ink ribbon and tension limit means will keep the tension of ink ribbon and remain the line velocity of ink ribbon in a constant without changing by the radius of ink ribbon rollers increasing or decreasing.. 13.

(24) 2.3.3 Paper Feeding Module. Here the paper feed also need at least one motor for driving the paper rollers to draw the paper into printer.. As mention before, there are three times repeating from step 2 to step 3 to form the colorful image.. In general thermal transfer printer, it may need three or four motors to drive. the paper feed, thermal print head movement and wind ink ribbon. will cause more power consumption and larger space.. And using more motors. Therefore, how to drive all these three. parts with fewer motors is important.. 2.4 Remarks. 1. Dye diffusion thermal transfer and variable dot thermal wax transfer are better choices for using on mobile printer. 2. Most of the mobile printers on the market use dye diffusion thermal transfer printing technology now. 3. Thermal print head module, ink ribbon module and paper feeding module are the main parts for the design of print module. 4. General thermal transfer printers use three motors to complete the whole printing process.. 14.

(25) Fig.2.1 Inkjet - Thermal bubble [5]. Fig.2.2 Inkjet – Piezoelectric [5]. 15.

(26) Fig.2.3 Basic laser printer components [6]. Fig.2.4 The path of paper in laser printer. 16.

(27) Fig.2.5 Dye diffusion thermal transfer [7]. 17.

(28) Ribbon Roller. Print Head. Ribbon Roller. Paper. Platen. Fig.2.6 Step1 – Ribbon search in dye diffusion thermal transfer. Ribbon Roller. Print Head. Ribbon Roller. Paper. Platen. Fig.2.7 Step2 – Paper feed in dye diffusion thermal transfer. Ribbon Roller. Ribbon Roller. Print Head Paper. Platen. Fig.2.8 Step3 – Print in dye diffusion thermal transfer. 18.

(29) Fig.2.9 Thermal wax transfer [8]. Fig.2.10 Variable dot thermal wax transfer [8]. 19.

(30) Black. Gray. Light gray. White. Fig.2.11 Dithering technique. Fig.2.12 Fig. 2.12 Continuous tone and half tone [7]. 20.

(31) Table 2.1 Comparison of thermal printing technologies Technology Dye Diffusion Thermal Transfer. Thermal Wax Transfer. Variable Dot Thermal Wax Transfer. Preservation. Good. Good. Good. Configuration. Simple. Simple. Simple. Color performance. Best. Good. Better. Continuous printing. Bad. Good. Good. Power consumption. Higher. Lower. Lower. Cost. Higher. Lower. Lower. Function. Fig.2.13 Portion of 300 dpi image printed on thermal printing technologies [8]. 21.

(32) Table 2.2 Canon’s products Company. CANON. CANON. CANON. CANON. Model. CP-330. CP-300. CP-220. CP-200. Printing Method. Dye Sublimation. Dye Sublimation. Dye Sublimation. Dye Sublimation. Physical Dimensions (W*H*D). 170x123x55 (mm). 170x55x123 (mm). 170x119x54.8 (mm). 170x119x54.8 (mm). Weight(g). 860. 860. 820. 820. Photo. Printing Time (sec) Resolution. Postcard Size: 85 Postcard Size: 85 Postcard Size: 85 Postcard Size: 85 Credit Card Size: 40 Credit Card Size: 40 Credit Card Size: 40 Credit Card Size: 40 8-Mini Labels: 40 8-Mini Labels: 40 8-Mini Labels: 40 8-Mini Labels: 40 Wide Size: 106 Wide Size: 106 300x300 dpi. 300x300 dpi. 22. 300x300 dpi. 300x300 dpi.

(33) Table 2.3 Products of ALPS Company Model. ALPS PTMTL28. PTMTL27. PTMTL14. Photo. Variable Dot Thermal Variable Dot Thermal Wax Transfer Wax Transfer. Variable Dot Thermal Wax Transfer. Physical Dimensions (W*H*D). 96.6x17.4x61.1 (mm). 88.6x17.4x61.1 (mm). 71.6x17.4x61.1 (mm). Weight(g). 159. 148. 120. Printing Time (sec). 90. 90. 60. Resolution. 290 dpi. 254 dpi. 203 dpi. Paper Size (mm). 85x54. 91x55. 69x38. Printing Method. 23.

(34) Table 2.4 Products of other companies Company. Kodak. Fuji Film. OLYMPUS. PANASONIC. Model. Printer Dock Plus. NP-1. P-200. SV-P20. Printing Method. Dye Sublimation. N/A. Dye Sublimation. Variable Dot Thermal Wax Transfer. Physical Dimensions (W*H*D). 334x188x83 (mm)(with tray). 117.5x41.5x105.5 (mm). 121x52x153 (mm). 111.1x35x68.3 (mm). Weight(g). 1110. 250. 830. 267.86. Photo. Printing Time (sec). 60. 40. 90. 95 sec/sheet (AC Adaptor); 120 sec/sheet (Battery). Resolution. N/A. 254 dpi. 320 dpi. 290 dpi. Paper Size (mm). MAX: 184x102 MIN: 51x34. 86x54. 80x125.6. 85.725x54. 24.

(35) Fig.2.14 Subsystem of thermal printer. 25.

(36) Chapter 3 Design Method and Requirements. 3.1 TRIZ. 3.1.1 Introduction of TRIZ. TRIZ, as a Russian abbreviation, is equal to “Theory of Innovative Problem Solving” (TIPS).. And it was born in the second half of the twentieth century and developed by. Genrich Altshuller and his colleagues. Now it is being developed and practiced throughout the world [9].. Before TRIZ, authorized thought about creative and human innovations was based on a paradigm that believed the creation as an unknown phenomena.. But Altshuller believed that:. 1. Creation is not an unknown and unreachable function. 2. Creation followed a special and achievable principles. 3. It is possible to do the inventions with non-inventor persons, if they learn the innovating principles and algorithms.. TRIZ research began with the assumption that there are universal principles of invention that are the basis for creative innovations that advance technology, and that if these principles could be identified and codified, they could be taught to people to make the process of invention more predictable. years.. The research has proceeded in several stages over the last 50. Over 2 million patents have been examined, classified by level of inventiveness, and 26.

(37) analyzed to look for principles of innovation.. The three primary findings of this research are. as follows:. z. Problems and solutions were repeated across industries and sciences.. z. Patterns of technical evolution were repeated across industries and sciences.. z. Innovations used scientific effects outside the field where they were developed.. In the application of TRIZ all three of these findings are applied to create and to improve products, services, and systems.. 3.1.2 The Foundation of TRIZ. This section provides a short introduction to some basic TRIZ tools.. There are five. ideas in TRIZ, technical systems, levels of innovation, law of ideality, contradictions and evolution of technical systems [10].. Technical Systems. Everything that performs a function is a technical system. consist of one or more subsystems.. Any technical system can. Each of the subsystems is also a technical system unto. itself and each performs its own function.. The hierarchy of technical systems spans from the. least complex, with only two elements, to the most complex with many interacting elements. When a technical system produces inadequate or harmful functions, it may need to be improved.. This requires the imaginative reduction of the system to its simplest state. In. TRIZ, the simplest technical system consists of two elements with energy passing from one element to the other. 27.

(38) Levels of Innovation. Analysis of a large number of patents reveals that not every invention is equal in its inventive value.. Altshuller proposed five levels of innovation.. z. Level 1: A simple improvement of a technical system.. z. Level 2: An invention that includes the resolution of a technical contradiction.. z. Level 3: An invention containing a resolution of a physical contradiction.. z. Level 4: A new technology is developed containing a breakthrough solution that requires knowledge from different of science.. z. Level 5: Discovery of new phenomena. Altshuller concluded from his research that a large number of patents belong only to Level 1 and Level 2. Using TRIZ can help designers elevate the innovative solutions to Level 3 and Level 4.. Law of Ideality. The goal of any technical system is to provide some function.. And the Law of Ideality. means that the technical system can have the same functions without introducing any new mechanism or device into the system, and the system tends to become more effective, reliable and simple throughout its lifetime.. There are several ways to make a system more ideal:. 1. Increase the amount of functions of the system 2. Transfer as many functions as possible to that working element which produces the system’s final action 28.

(39) 3. Transfer some functions of the system to a supersystem or to the outside environment. 4. Utilize internal and external resources that already exist and are available.. Contradictions. Contradiction analysis is a powerful tool. As mentioned before, the most effective solutions are achieved when solving a technical problem which contains a contradiction. Contradictions can be divided into technical contradiction and physical contradiction. A technical contradiction occurs when designers try to improve one characteristic or parameter of the technical system and it causes another characteristic or parameter to worsen.. Physical. contradiction appears when two opposite properties are required from the same element of a technical system or from the technical system itself.. (A) Solving technical contradiction After Altshuller analyzed more than 40,000 patents, he generalized 40 inventive principles [11].. Altshuller developed contradiction matrix in 1970s, the column and. row of matrix include 39 features, as shown in Table 3.1. First process of this method is to find the parameter that designers want to improve in the column. relational harmful parameter in the row.. Then find the. The intersection of two parameters includes. some useful principles. All 40 principles are common concepts, as shown in Table 3.2; and designers must use creativity to let these principles apply questions.. (B) Solving physical contradiction The main technique of solving physical contradiction is “Separation”: separate factors in different space or time.. Use math model to describe as follows: assume. physical contradiction has form like parameter A > 0 , A < 0 at time t =ti , position X = 29.

(40) (xi, yi, zi) .. The method is let A > 0 at time t = tj , position X = (xj, yj, zj) ; A < 0 at time t. = tk , position X = (xk, yk, zk).. This way can solve contradiction A > 0 and A < 0. simultaneously.. Evolution of Technical Systems. Altshuller established eight Patterns, or Lines, of technical systems evolution:. 1. Life cycle 2. Dynamization 3. Multiplication cycle (Transition to Bi- or Poly- system) 4. Transition from macro to micro level 5. Synchronization 6. Scaling up or down 7. Uneven development of parts 8. Replacement of human (Automation). Designers can follow the eight patterns to realize the trend of evolution and get some innovative ideas from the index of system evolution.. 3.2 Requirements. Some requirements must be conformed when designing the print module on photo printer. For example, the number of motors, size, power consumption, cost, manufacture, etc. Because of the mobile requirement, the size and printing time are concerned at the beginning of design.. Therefore, the requirements for size and printing time are indicated in this 30.

(41) section.. 3.2.1 Size. Size of Component. Compared with general printer, the components for mobile printer, such as gears, motor, thermal print head, must be smaller to satisfy the mobile requirement.. During the design. process, the size of these components has to be concerned.. In order to satisfy the requirement, the size of print head used here is about 64mm*22.45mm*5mm, and the module number of gear used in power transmission is 0.3.. Allocation. In mobile printer, most of the space is used for the paper in and ink ribbon cassette. Therefore, the space for drive mechanism is less oppositely.. When considering the small. size for mobile, the allocation for all the components is important.. Furthermore, motor is one of the components with large size and much weight. Because all the three main parts, print head module, ink ribbon module and paper feed, need the driving means, at least three or four motors are required in general.. It results in the larger. size of the whole printer. Therefore, how to drive the three parts and the allocation of drive mechanism with fewer motors must be concerned, too.. 31.

(42) 3.2.2 Printing time. Another important requirement of mobile printer is the printing time.. If finishing one. colorful printing costs too much time, users may complain the product and reduce the interest to buy the product.. Here are two factors which will effect the total printing time.. Motor. Both the ribbon and paper are drawn by rollers which are driven by motors. the rotational speed of motor is the main factor to effect the printing time.. Therefore,. But the rotational. speed of motor will be limited by the accuracy, the heating elements on print head, etc.. Mechanism. Most of printers use about three motors to drive the whole print module.. Therefore,. each module, for example, the print head module or capstan roller, is driven by independent motor and it will not spend too much time while changing steps.. But when designing a. small print module, it may use some mechanism to reduce the number of motors.. Therefore,. it may take some time for change steps.. From the requirements above, using some mechanism design to reduce motors may be the better way to satisfy the requirements.. And it is the problem which should be solved first.. After that, the allocation of whole print module, including the print head module, the ribbon cassette and the transmitting mechanism, can be decided.. 32.

(43) 3.3 Objectives. After the marketing research, the objectives for the print module on mobile printer have been decided.. 1. Size: According to the present mobile printers, the average size is about 138mm*104.5mm*44mm, but the design of ALPS is smaller than other products. Therefore, the design of print module on mobile printer should be near or smaller to the size of ALPS products. 2. Printing time: Here ALPS PTMTL28 is the objective product. The printing time, 90s for one color photo print, is the objective value. 3. Motors: In order to increase the number of pieces which can be printed with charging the battery one time, the number of motors used in the print module must equal or less than two. 4. Steps: Fewer steps in the printing process can save more power and time.. At least there. should be 3 steps for printing, paper feeding and ribbon searching.. 3.4 Remarks. 1. TRIZ solves technical contradiction problems with contradiction matrix. 39 parameters and 40 principles are in the contradiction matrix. Principles are related to design parameters. 2. Space and printing time are the two main requirements for mobile at the beginning of design. 3. Motor reduction and driving mechanism are important to satisfy the requirements at the beginning of design. 33.

(44) Table 3.1 39 features of system 1. Weight of moving object. 2. Weight of stationary object. 3. Length of moving object. 4. Length of stationary object. 5. Area of moving object. 6. Area of stationary object. 7. Volume of moving object. 8. Volume of stationary object. 9. Speed. 10. Force. 11. Stress or pressure. 12. Shape. 13. Stability of the object's composition. 14. Strength. 15. Duration of action by a moving object. 16. Duration of action by a stationary object. 17. Temperature. 18. Illumination intensity. 19. Use of energy by moving object. 20. Use of energy by stationary object. 21. Power. 22. Loss of energy. 23. Loss of substance. 24. Loss of information. 25. Loss of time. 26. Quality of substance/the matter. 27. Reliability. 28. Measurement accuracy. 29. Manufacturing precision. 30. External harm affects the object. 31. Object-generated harmful factors. 32. Ease of manufacture. 33. Ease of operation. 34. Ease of repair. 35. Adaptability re versatility. 36. Device complexity. 37. Difficulty of detecting and measuring. 38. Extent of automation. 39. Productivity. 34.

(45) Table 3.2 40 principles 1. Segmentation. 21. Skipping. 2. Separtion. 22. "Blessing in disguise". 3. Local quality. 23. Feedback. 4. Asymmetry. 24. Intermediary'. 5. Merging. 25. Self-service. 6. Universality. 26. Copying. 7. Nested doll. 27. Cheap short-living objects. 8. Anti-weight. 28. Mechanics substitution. 9. Preliminary anti-action. 29. Pneumatics and hydraulics. 10 Preliminary action. 30. Flexible shells and thin films. 11 Beforehand cushioning. 31. Porous materials. 12 Equipotential. 32. Color changes. 13 The other way round'. 33. Homogeneity. 14 Spheroidality - curvature. 34. Discarding and recovering. 15 Dynamics. 35. Parameter changes. 16 Partial or excessive actions. 36. Phase transitions. 17 Another dimension. 37. Thermal expansion. 18 Mechanical vibration. 38. Strong oxidants. 19 Periodic action. 39. Inert atmosphere. 20 Continuity of useful action. 40. Composite structures. 35.

(46) Chapter 4 Conceptual Design. 4.1 Present Designs In order to avoid infringing the present designs or products, searching related information is necessary. The patents about the mechanism of small printer using thermal transfer are very less. Many of the patents focus on the control system or the process of thermal transfer to form images on the paper.. General printers use more than one motor to control the whole print module for completing the printing process.. As shown in Fig. 4.1 and Fig. 4.2, the mobile photo printer. uses three motors (Number 41, 46, 48) [12].. But there is another mobile printer design. worth to notice. It is the product of ALPS, as shown in Fig. 4.3 and Fig. 4.4 [13]. only one motor used in the printer design of ALPS.. There is. It uses a special cam gear A and two. planet gears B3 and B4 to change the modes in printing process, as shown in Fig. 4.5 and Fig. 4.6.. Besides, there are two differences between ALPS design and general printers. One is. that the ribbon rollers in general ink ribbon cassette is far from each other, but the rollers in ALPS design are at the same side [14].. Therefore, the size can be reduced because the two. spaces for ribbon in the ribbon cassette are combined into one space. Another difference between ALPS printers and general printers is that the print head is active and platen roller is fixed in normal printer, but in ALPS printers the print head is fixed and platen roller is active to be pressed against print head or leave print head.. Fig. 4.5 shows the shape of cam gear A.. There are two recesses (A1, A2) and two ends. of slot (A3, A4) worth to notice on cam gear A and two areas without teeth. Behind the cam. 36.

(47) gear, there are two cams, one for ribbon lever and another for platen roller. Fig. 4.6 shows that the lever B is concentric with sun gear B1 and can swing up and down with it.. On the. lever B there are two planet gears (B3 and B4) and one stud B2 constrained in the slot of cam gear A. The sun gear B1 drives capstan gear and capstan roller by transmitting gear train. Capstan roller drives paper in or out of the printer.. 4.1.1 Steps of Printing Process in ALPS. Step 1: Ribbon searching – When ribbon searching, the upper planet gear B3 tends to drive the cam gear A but the stud B2 is stopped by the recess A1 so that the planet gear B3 does not engage the cam gear A and the cam gear stays. At this time, ribbon lever is rotated by the clockwise rotation of sun gear B1 and the ribbon gear engages the gear which connects to ribbon roller to wind the ribbon. (Fig. 4.7). Step Changing – After the ribbon is in correct position, the sun gear starts to rotate counterclockwise so that the stud B2 leaves the recess A1 of slot on cam gear and lever B rotates counterclockwise to let lower planet gear B4 drives the cam gear A. Therefore, the cam gear A also rotates counterclockwise. (Fig. 4.8). Step 2: Feeding Paper Forward – When the stud B2 is around the second recess A2 on cam slot, the sun gear B1 rotates clockwise to let the stud get into the recess.. At this step the. upper end of ribbon lever is stopped by the ribbon cam behind the cam gear so that the ribbon gear can’t drive the ribbon roller. Therefore, paper is drawn into the printer by capstan roller to detect the length of paper without driving ribbon (Same as the printing direction). (Fig. 4.9). Step 3: Feeding Paper Backward – After detecting the length of paper, The sun gear B1 37.

(48) rotates counterclockwise to change step from 2 to 3.. When the stud B2 arrives to one end of. the slot A3, there is an area without teeth close to top side of cam gear and lower planet gear B4 will enter the area. Therefore, the cam gear A will stop since lower planet gear B4 can not drive it any more.. Meanwhile the stud B2 is at the end of slot causing the lever and cam. both stay. At this time, paper is drawn by capstan roller in the opposite direction, and the ribbon lever is still stopped by the ribbon cam so that the ribbon won’t be winded. (Fig. 4.10). Step 4: Printing – While printing, the sun gear B1 rotates clockwise to change step from 3 to 4.. The stud B2 follows the inner slot from the end of slot A3 to the end of slot A4 and. the platen roller will be pressed against print head by the cam for platen roller behind the cam gear A.. There is another area without teeth at middle layer of cam gear A.. When the stud. B2 reaches the end A4, upper planet gear B3 enters the area without teeth at the same time. Therefore, the cam gear will stop. After that, the sun gear B1 rotates clockwise continuously and ribbon gear on ribbon lever will engage the gear connected to ribbon roller. (Fig. 4.11). 4.2 Conceptual Designs. In this section, several conceptual designs of print module mechanism are proposed.. 4.2.1 Concept 1. The concept 1 is shown in Fig. 4.12.. It is similar to normal printer design, but ink. ribbon roller and capstan roller are driven by the same motor.. Therefore, there are only two. motors used in the design.. The concept 1 can be divided into two sections. Section 1 is the transmission for paper 38.

(49) and ribbon, as shown in Fig. 4.13. Fig. 4.14.. Section 2 is the transmission for print head as shown in. In section 1, gear C is connected to capstan roller for feeding paper and it always. engages sun gear A.. There is a planet gear E at the end of ribbon lever D.. Gear B connects. to ribbon roller.. Step 1: Ribbon Searching – While searching the correct position of ribbon, sun gear A is driven by motor and rotates clockwise. the same direction.. The ribbon lever D will rotate with sun gear A in. Therefore, ribbon gear E will engage gear B to drive the ribbon roller.. (Fig. 4.15). Step 2: Paper Feeding – After the ribbon gets in the right position, users put the paper into printer and motor rotates in the opposite direction so that ribbon lever D rotates counterclockwise because of the opposite rotating direction of sun gear A.. Therefore, ribbon. gear E disengages gear B and ribbon will not be winded while feeding paper into printer. (Fig. 4.16). Step 3: Printing – When the paper and ribbon are both at the right positions, another motor 2 will act and the cam F will rotate 180 degrees to press the thermal print head against the platen roller. After that, motor 1 will rotate in the same direction of step 1 and ribbon gear will engage gear B to complete one color printing. (Fig. 4.17). When one color is printed on the paper, motor 2 acts again and the cam E will rotate 180 degrees to release the print head. After print head released, the mechanism will change to step 2 to draw paper into printer again for the next color printing.. When the three colors and. one coating layer are printed, the whole printing process is complete.. 39.

(50) 4.2.2 Concept 2. Because of the requirement of power consumption, the motors should be reduced. But each part needs the energy to be driven. characteristics.. Therefore, there is a contradiction between the two. Table 4.1 shows that use the contradiction of these two characteristics,. “Power” which is improved and “Use of energy by a moving object” which is getting worse, to find principles in the contradiction matrix. In the contradiction matrix there are four principles that can solve the contradiction.. Principle 6: Universality Principle 16: Partial or excessive actions Principle 19: Periodic action Principle 37: Thermal expansion. Concept 2 is produced by using the principle 6. used in concept 2. source.. Fig. 4.18 shows there are two motors. Concept 2 can be separated into three sections. Section 1 is the power. Motor 1 transmits power to compound gear A, as shown in Fig. 4.19.. As shown in. Fig. 4.20, section 2 is the step-changing device that consists of a motor 2, a cam C and a rotating arm B.. There are two small gears D1 and D2 which are fixed together and can. rotate freely at the end of rotating arm B. Cam C and rotating arm B are fixed on the axis of motor 2 and gear A in section 1 can rotate freely on the axis of motor 2. the gear with smaller pitch diameter of gear A. and gear H transmit power to ribbon roller. roller.. Gear D2 engages. Section 3 is the three step gears set. Gear E Gear F and gear G transmits power to capstan. Gear H and gear G are not fixed together and can rotate individually. (Fig. 4.21). Step 1: Ribbon Searching – As shown in Fig. 4.22, motor 2 doesn’t act and the rotating 40.

(51) arm B stays so that gear D2 engages gear E and motor 1 can transmit power to ribbon roller.. Step 2: Paper Feeding – After ribbon searching, motor 1 stops and motor 2 acts to rotate rotating arm B about 90 degrees clockwise so that gear D1 will engage gear F.. Then motor 1. will act to transmit power to capstan roller. (Fig. 4.23). Step 3: Printing – While Ribbon searching and paper feeding are done, motor 2 rotates 90 degrees again and gear D1 and D2 at the end of rotating arm can engage gear G and gear H. Cam C also presses print head against platen roller simultaneously because of the action of motor 2.. Then motor 1 act to transmit power to ribbon roller and capstan roller at the same. time and complete one color printing. (Fig. 4.24). After repeating the step 2 to step 3 for four times, the whole printing process is finished.. 4.2.3 Concept 3. Concept 3 is generated by the innovative design method “SCAMPER check list” and the technique “Transfer” is used. gears to transmit power.. In the manual gearbox of car, the clutch engages different. And the printer design here is similar because there must be fewer. motors used in printer design so that step-changing to complete the printing process is important.. Therefore, this idea of gearbox in car is transferred into concept 3.. 2, concept 3 also uses a motor to switch the steps, as shown in Fig. 4.25.. As concept. And it can be. divided into three sections.. Fig. 4.26 shows section 1 is the power source of the printer. longer than general gears.. And the gears here are. Motor 1 can transmit power to gear A. 41. Section 2 is the.

(52) step-changing device, as shown in Fig. 4.27.. The axis of motor 2 is longer than general. motor and there is a spiral gear B fixed on it.. There is also spiral shape in the inner side of. Gear C. and the teeth at the two sides of gear C are sharpened so that gear C can shift along the motor axis to engage other gears.. In section 3, shown in Fig. 4.28, there are three gears. on the same axis and they can rotate freely and individually. Gear F connects to ribbon roller.. Gear E connects to capstan roller and gear D connects to a cam that can press print. head against platen roller or release it.. Also, both sides of the three gears have to be. sharpened.. Step 1: Ribbon Searching – At this time motor 2 acts and drives gear C to engage ribbon gear F. Then motor 1 acts to transmit power to ribbon roller and wind ribbon to right position. (Fig. 4.29). Step 2: Paper Feeding – Motor 2 acts again and drives gear C to engage gear E, and motor 1 transmits power to capstan roller drawing paper into printer after gear C and gear E engage together. (Fig. 4.30). Step 3: Pressing Print Head – After step 2 and 3, gear C is driven by motor 2 to engage gear D. And gear D will drive the cam (Not shown) to press print head against platen roller by the power transmitted from motor 1. (Fig. 4.31). Step 4: Printing – At this step gear C will be driven by motor 2 to engage gear E and gear F.. And then motor 1 acts to draw paper and wind ribbon simultaneously for one color. printing. (Fig. 4.32). After one color printed, printer will go back to step 3, but this time cam will rotate 180 42.

(53) degrees to release print head, and then go back to step 2 drawing paper into printer again. Next, follow step 3 and step 4 to complete another color printing. After all the colors and coating are printed, the printing process is completed.. 4.2.4 Concept 4. Concept 4 is also generated by using the technique “Transfer” of innovative design method “SCAMPER check list”. Here the principle of the device to press or release print head is like a click ball-point pen. Fig. 4.33 is the 3D view of concept 4.. Concept 4 can be. divided into two sections.. Section 1, as shown in Fig. 4.34, is the device for pressing or releasing print head. There are two deformable arms B1 and B2 at one side and some teeth on the other side of component B.. There is a bayonet on both of the deformable arms B1 and B2, and a spring. under compound B.. One end is fixed on the printer frame and the other is fixed on the. bottom of compound B.. Compound B is fixed with print head (Not shown). Component A. is an electromagnetic switch.. The mechanism of section 2 is the same as section 1 in. concept 1, as shown in Fig. 4.35. ribbon roller.. Gear D connects to capstan roller and gear H connects to. But there is a gear engaging sun gear C which connects to gear I in section 1.. The process for pressing or releasing print head. Fig. 4.36 is the state that the print head is released.. In this state, the deformable arm B2. is locked at the aperture of frame and spring is tensioned. While entering the step of printing, the electromagnetic switch A will push to the aperture and B2 is deformed, as shown in Fig. 4.37.. At this time, spring will pull compound B down and the teeth at the right side will 43.

(54) engage gear I.. In the state of Fig. 4.38, electromagnetic switch A will restore to the normal. state, and spring is not pressed or tensioned, but gear I will rotate by the power of motor and continue to push compound B down. In the state of Fig. 4.39, deformable arm B1 enters the aperture of frame and locked. and spring is compressed.. The teeth on the right side of compound B don’t engage gear I. Print head is pressed against the platen roller in the state.. If. releasing print head, the process is opposite to the process of pressing print head.. Step 1: Ribbon Searching – In this step, section 1 is not active and the state of section 2 is the same as the step 1 of section 1 in concept 1.. Ribbon gear G engages gear H and. transmits power to ribbon roller. (Fig. 4.40). Step 2: Paper Feeding – Section 1 is also not active, and the step is the same as step 2 of section 1 in concept 1, too. (Fig. 4.41). Step 3: Printing – In this step, section 1 will follow the process of pressing print head. After that, motor will act and drive paper and ribbon simultaneously for printing. (Fig. 4.42). For the next color printing, section 1 will release print head and section 2 will repeat step 2 to step 3 until the printing process finishes.. 4.2.5 Concept 5. Fig. 4.43 shows the mechanism of Concept 5 which is similar to concept 2, but there is only one motor used.. In the printer design of ALPS and the concepts above, they all use the. clockwise or counterclockwise rotation of motor to drive ribbon roller and capstan roller. But in concept 5, one directional rotation of motor is used to drive ribbon roller and capstan roller, 44.