TW539623B - Method for increasing print speed of a thermal print head - Google Patents

Abstract

A method is provided to increase the printing efficiency with flexible adjusting the gray level resolution. The thermal print head includes a plurality of linearly arranged and equally spaced heaters which are used to heat the color dye on a color tape so as to deposit the color dye on a paper to form a line image. The line image contains a plurality of pixels and each pixel is formed by one heater. When generating a pixel, a pulse sequence is fed to one heater to control the heating period of the heater. The pulse sequence contains a plurality of consecutive pulses which is used to generate the related gray level. We can apply this method to decrease the pulse number with flexible adjusting the gray level resolution to improve the print quality and efficiency.

Description

539623 V. Description of the invention (1) Field of the invention: The present invention provides a method for increasing the number of gray levels and printing efficiency of a thermal print head, which can increase the color density resolution and improve the printing efficiency. Background note: The main difference between photo printers and ordinary printers is that photo printers can print higher quality images, such as high-quality photos. Please refer to Figure — and Figure 2. FIG. 1 is a schematic diagram of a conventional photo print Λ10. Figure 2 is a schematic diagram of the printing feed mode of the conventional photo printer 10. As shown in Figure 1, the conventional photo printer 10 includes a ribbon 14 which is provided with a plurality of dye blocks for storing color dyes of different colors. A thermal print head 12 is fixed to the photo. The printer 10 is used to heat a dye so that the color dye can be printed on a photo paper 16 and a ribbon moving device 18 is used to move the ribbon 14 to make the thermal print head 12 is able to print the dyes stored in the plurality of dye blocks on the ribbon 14 to the photo paper 16 and a roller group 20 is used to fix and move the photo paper 16 in a predetermined direction to make the heat The print head 12 can print a color graphic on the photo paper 16. As shown in FIG. 2, the thermal print head 12 includes a plurality of linear and equidistant heaters 22 for heating the ribbon 14 so that the color dye on the ribbon 14 is heated by heat. Sublimation is attached to the photo paper 16, where each of the thermal print heads 2 is heated when the thermal print head 12 is used to heat the photo paper 16

539623 V. Description of the invention (2) The device 2 2 will heat the ribbon 1 4 and generate a plurality of corresponding printing dots X 1 on the photo paper 16 to form a linear image γ 1. After that, the photo paper 1 6 will move the roller group 20 along the predetermined direction at a predetermined speed, so that the thermal print head 12 can print another linear image γ 2 on the photo paper 16. In this way, a plurality of linear images are continuously printed on the photo paper 16 until the photo paper 16 is filled with the linear images, and the printing process of the photo paper i 6 is completed. From the above, it can be known that the number of adders 22 on the thermal print head 2 determines the number of print points χ 丨 on each linear image. In addition, the length of the heating time and the number of heating times for each pair of ribbons 22 and 4 of each heater 22 will determine the color density of the printing dot X1 corresponding to each heater 22 2 on the photo paper. The color density is The so-called grayscale. Please refer to the hot print head, the display of the signal, the display of the signal and the phase. The digital phase of the 2nd phase will be turned on at the same time. ^) A predetermined temperature 0 will be based on the phase diagrams 3A and 3b. Fig. 3a is the color density gray level of the conventional photo printer i 〇 and the time pulse sequence on the heater 2 2 ~ Fig. 2B is the sequence signal of the time pulse sequence of the heater 22 in Fig. 3A to f The schematic. As shown in Figures 3A and 3B, the thermal print head 10 of the printer 10 2 prints photo paper 6 before ^ ^ a plurality of heaters 2 2 on the print head 1 2 (turn on the heater ^ 'The digital signal value of the heater 2 2 is turned off ^ this ^ P so that all the heaters 2 2 of the thermal print head 12 reach a sheet of paper is called the preheating stage, and then, the photo printer' 1 6jl A plurality of corresponding ones of the plurality of linear images

539623

xi „r; te corresponds to color = chen degree), to continuously turn on the plurality of heating on the thermal print head 丨 2 | § 22. Among them, the heating time of the heater 22 can be a time pulse sequence 30 and phase The corresponding sequence is digitally represented, and each 32 time interval (the width of Tu varies with the printing material characteristics and the corresponding gray level 0 value; ^ is different) is the time to turn on the heater 22. The thermal print head 12 of the printer 10 divides the number of gray levels of the printing point χι into 2 5 6 levels, the lightest color is gray level 0, and the darkest color is gray level 2 5 5. That is, When the number of gray levels of the printing point X1 is a gray level Chansi, where ^, N is an integer greater than or equal to 0 and less than or equal to 255, the heater 22 corresponding to the printing point and η phase must be in the After the warm-up period, the dirty unit heating time is continuously turned on, that is, N consecutive time pulses are input or N digital signals are inputted on the sequence JN bit. Because of the printing dot X1 on each linear image on the photo paper 6 The color density may be darker or lighter, so = qfan, the mother prints a linear image 'plurality 22 are heat must be done 255 times the pulse length of time. If you want to increase the printing speed, it must reduce the number of time of the pulse, thus reducing the gray scale resolution will affect printing quality Y '

Summary of the Invention: Therefore, the present invention provides a printing method for elastically arranging printing pulses to achieve the purpose of improving the color density gray level number and printing efficiency. /

Page 7 539623 V. Description of the invention (4) | Detailed description of the invention · Method I :: The structure of the f printer and the thermal print head and the printing feed. For example, the conventional technology shown in Xi Qu is the same, so it will not be repeated-Photo; ^ The 'The thermal print head of the photo printer of the present invention is printing (turn on the heating H and turn on the thermal printing The value of I of the heaters of the head 1 is —— / V hole number is M ′, the digital signal of the heater is turned off 丨 -predetermined 彳 ... 1 Tp to make all the forces of the thermal printing head ... :: Temperature, this is the preheating stage. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, A ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, (,,,,,,,,,,,, and Corresponding to the required I | successively turn on the heaters of the siege 歹 iJ print head i. Due to the length of the heating time of each heater 俺 = color / degree is controlled by a predetermined number of gray levels When the multiple plus ::: ,, r fixed printing dots X2 are turned on, each printed dot X2 is correspondingly added; the number of heating times is the number of gray levels of color density generated by each printed dot X2. The conventional thermal printing device, for the performance of different color levels, just enters the number of heating times that belongs to the color level into the thermal print head and heats it, and the actual printing In addition to the fixed energy required to convert the printing medium, the excess energy will accumulate in the system and cause the system temperature to rise, affecting the next | heating; and the more consecutive printing times, the more the heat accumulation Many, p. 8 539623 V. Description of the invention (5) In this kind of situation, it is necessary to use a temperature sensing device to detect the temperature and change the time of each heating according to the detected temperature to achieve color gradation balance and maintain printing quality. The present invention uses the above-mentioned heat accumulation effect. For the same heating times and length of time, since the heat accumulation effect of continuous printing is greater than that of discontinuous printing, the color density will also be different. From another perspective, we can change A fixed number of prints will have different levels of gradation due to changing the continuity of printing. With this characteristic, the same gradation resolution can be completed with less heating and transmission data. Please refer to Figure 4 B, FIG. 4B is a schematic diagram of serial digital signal data using a discontinuous heating method combined with a heat accumulation effect to reduce the number of heating times of a thermal print head according to an embodiment of the present invention. Here we define the total number of gray levels as 2 5 6 and the number of gray levels in the segment as 3. The number of heating levels in the segment is 2 and the number of preheating heating is 1. Therefore, the total number of heating in this embodiment is 1 7 1. Compared with the traditional 2 5 5, it greatly reduces and effectively increases the printing speed. As can be seen from Figure 4A, when grayscale printing, due to the characteristics of the printing material, the system needs to supply a The initial heat enables the color of the ribbon to be stably output, so a length of Tp is given to achieve this purpose. This heating behavior is called preheating. The preheating method and length vary with different printing materials and the environment. Explored in this patent.

Page 9 539623 V. Description of the invention (6)

Compare the gray scale 1 and the gray scale ratio to 0 L heating pulses. • Because of the ratio: J p pulses are not considered, although there are only, the remaining (a) t is left after printing (preheating Tp) when the gray scale 1 is printed. The size of the previous column will also affect the column = residual heat is less than the residual heat of gray level 2. Because the number of printing pulses is more than s, although the number of printing pulses is T, the gray level 1 and gray level ^ But as long as the position of the heating pulse is changed, fewer colors can be used: the shades are distinguished, and this feature is used. , Σ *, ,, times complete a relatively large number of color analysis

V It is hereby pointed out that the fixing device for fixing the photo printer described in the embodiment 2 is used in a way to put the ribbon on the road = a photo paper, and the thermal printing master is fixed in this way. Therefore, the dye of column 3 is printed on the photo paper. Not only as on a film printer, the: head can also be moved in a movable manner: the thermal printing C device is used to fix the photo paper, and then :: is to the photo paper. The Λ 'line method increases the printing speed of the dyes contained in the ribbon by increasing the printing speed of the thermal print head to ΓΓ, and increasing the printing speed to 4% —τ ^ The resolution of the gray scale is based on the printing density of the mother dot and the printed dot of the present invention. In this way, the production cost is also reduced. Famous + long time

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Page 11 539623 Brief description of the diagram Brief description of the diagram: Figure 1 is a schematic diagram of a conventional photo printer. Figure 2 is a schematic diagram of the printing feed mode of a conventional photo printer. Figure 3A is a schematic diagram of the gray density of the color density of the thermal print head of a conventional photo printer and the time pulse sequence signal on the heater. Figure 3B is a schematic diagram of the time pulse sequence signal of the heater and the corresponding serial digital signal data in Figure 3A. FIG. 4A is a schematic diagram of the color density gray level of the thermal print head and the time pulse sequence signal on the heater according to the embodiment of the present invention. Figure 4B is a schematic diagram of the time pulse sequence signal of the heater and the corresponding sequence digital signal data in Figure 4A. The heating number equation of the human-based patent, the factors that affect the heating number in the formula include: total gray level, segment gray level, segment gray level using heating number and preheating number. Taking Figure 3B as an example, the total number of gray levels is 2 5 6 and the number of gray levels in the zone is 3. The number of heating levels in the zone is 2 and the number of preheating is 1. The total number of heating is 171. Explanation of symbols in the figure: 7 0 time pulse sequence T u unit heating time 72 unit time pulse Tp warm-up time

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Claims (1)

539623 _ Case No. 91100339_ Year Month Amendment _ 6. Patent Application Range 6. The method described in item 2 of the patent application range, wherein the printer provides the plural number according to the printing speed of the thermal print head Heating pulses. 7. The method according to item 2 of the scope of patent application, wherein the number of the plurality of heating pulses provided by the printer is less than the number of gray levels of the pixels. Page 14