JP2012213861A - Print data processor and print data processing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a print data processor and a print data processing program, for preventing color mixture from occurring on the boundary between a character and background.SOLUTION: A CPU of a printer executes contour pixel extraction processing on character data of an input character (S33). In the contour pixel extraction processing, contour pixels are extracted for forming the contour of the character that is a boundary from background pixels. In adjacent pixel correction processing 1, a first adjacent pixel adjacent to the contour pixels extracted out of the background pixels in S33 is extracted (S37). The first adjacent pixel is set in white, and processed background images and the character data are synthesized and stored (S41). The color mixture of the background images and the character due to thermal storage of a thermal head can be prevented.

Description

  The present invention relates to a print data processing apparatus and a print data processing program that can be suitably used in a thermal printer including a thermal head provided with a plurality of heating elements.

  In general, a thermal printer includes a thermal head having a plurality of heating elements, and heat is generated by energizing each heating element to develop color on thermal paper or to form a heat-dissolving ink in a predetermined pattern on a printing medium. Transfer and print.

  By the way, a heat generating element accumulates heat as printing progresses. Therefore, for example, when printing an image in which characters are superimposed on a background image, the background pixels adjacent to the characters are colored by the heat stored in the heating element when the characters are printed, and color mixing occurs at the boundary between the characters and the background. Sometimes. When solid areas are continuous, color unevenness and blurring due to heat storage may occur. To prevent this, a method of thinning out the solid areas has been proposed (see, for example, Patent Document 1).

JP 2001-96788 A

  However, the method described in Patent Document 1 only thins out the solid area when the solid area continues. Therefore, it was not possible to prevent color mixing at the boundary between the character and the background.

  An object of the present invention is to provide a print data processing apparatus and a print data processing program that can prevent color mixing at the boundary between a character and a background.

  A print data processing apparatus according to a first aspect of the present invention is image data for printing a character on a print medium using a thermal printer, and a background constituting a character pixel constituting the character and a background of the character Pixel extraction means for extracting the character pixel at a position that makes a boundary with the background pixel from the image data including the pixel as a contour pixel; and at least one pixel along the contour pixel extracted by the pixel extraction means Color tone conversion means for converting the color tone of the background pixel to white by width. In this aspect, a white portion can be formed along the outline of the character. Therefore, color mixing can be prevented from occurring at the boundary between the character and the background.

  In the first aspect, the temperature detection means for detecting the temperature of the thermal head provided in the thermal printer, and the color tone conversion means converts the color tone of the background pixel to white according to the detection result of the temperature detection means. First color calculation means for calculating the number of pixels corresponding to the width, and the color tone conversion means may convert the color tone of the background pixel to white with the width of the pixel number calculated by the first calculation means. . In this aspect, the number of pixels corresponding to the width for converting the color tone to white is calculated according to the temperature of the thermal head. Color mixing is likely to occur when the temperature of the thermal head is high. In this case, the number of pixels corresponding to the width for converting the color tone to white is increased. Therefore, it is possible to prevent color mixing at the boundary between the character and the background.

  In the first aspect, when the print medium feeding direction during printing by the thermal printer is a downstream direction, and the opposite direction is an upstream direction, the color tone conversion means is located in the upstream direction of the contour pixel. The number of pixels corresponding to the width for converting the color tone of the background pixel to white may be larger than the number of pixels corresponding to the width for converting the color tone of the background pixel located in the downstream direction to white. In this aspect, the number of pixels corresponding to the width for converting the color tone to white is increased in the background pixels located in the upstream direction where color mixing is likely to occur. Therefore, it is possible to prevent color mixing at the boundary between the character and the background.

  Further, in the first aspect, the counting means for counting the number of printed sheets printed by the thermal printer, and the color conversion means converts the color tone of the background pixel to white according to the counting result of the counting means. A second calculation unit that calculates the number of pixels, and the color tone conversion unit may convert the color tone of the background pixel to white with a width of the number of pixels calculated by the second calculation unit. In this aspect, the number of pixels corresponding to the width that makes the color tone white is calculated according to the number of printed sheets. Therefore, even if the temperature of the thermal head increases due to continuous printing, color mixing can be prevented from occurring at the boundary between the character and the background.

  A print data processing program according to a second aspect of the present invention is image data for printing a character on a print medium using a thermal printer, and a background constituting a character pixel constituting the character and a background of the character A pixel extraction step for extracting the character pixel at a position that forms a boundary with the background pixel from the image data including the pixel as a contour pixel; and at least one pixel along the contour pixel extracted in the pixel extraction step And a color tone conversion step of converting the color tone of the background pixel to white with a width of. By causing the computer to execute the print data processing program of this aspect, it is possible to form a white portion along the outline of the character. Therefore, color mixing can be prevented from occurring at the boundary between the character and the background.

2 is a plan view of the printing apparatus 1. FIG. FIG. 2 is a block diagram illustrating an electrical configuration of the printing apparatus 1. It is a flowchart of a printing process. 6 is a flowchart of print data processing. It is a flowchart of an outline pixel extraction process. It is a figure for demonstrating the specific example of the pixel extraction in 1st Embodiment. 6 is a flowchart of adjacent pixel correction processing 1; 10 is a flowchart of adjacent pixel correction processing 2 (second embodiment). It is a figure for demonstrating the specific example of the pixel extraction in 2nd Embodiment.

  Hereinafter, a printing apparatus 1 according to a first embodiment of the present invention will be described with reference to the drawings. These drawings are used to explain technical features that can be adopted by the present invention, and the described apparatus, the configuration of the apparatus, flowcharts of various processes, and the like are merely illustrative examples.

  A physical configuration of the printing apparatus 1 will be described with reference to FIG. The printing apparatus 1 is provided with a keyboard 6 and a liquid crystal display 7 (hereinafter referred to as LCD 7) on the front side of the upper surface. The keyboard 6 includes a character input key 2, a print key 3, a return key 4, a cursor key 10, and the like. The printer 1 is provided with a cassette housing portion 8 on the rear side of the upper surface. The cassette storage unit 8 stores a tape cassette (not shown). The cassette storage portion 8 is covered with a storage cover 8A. A thermal head 9 is provided in the cassette housing portion 8. The thermal head 9 includes a plurality of heating elements. The printer 1 generates heat by controlling the energization amount of the heating element. A print medium such as thermal paper is conveyed to the thermal head 9 that generates heat. Predetermined printing is performed on the printing medium in contact with the thermal head 9. A label discharge port 16 is formed in the left side surface portion of the cassette housing portion 8. The label discharge port 16 discharges the printed print medium. A control board 12 is disposed below the keyboard 6.

  The electrical configuration of the printing apparatus 1 will be described with reference to FIG. The printing apparatus 1 includes a control circuit unit 20 on a control board 12 (see FIG. 1). The control circuit unit 20 includes a CPU 21, an input / output interface 23 connected to the CPU 21 via a data bus 22, a CGROM 24, a dot pattern ROM 25, a ROM 26, and a RAM 27.

  The CGROM 24 stores dot pattern data for display corresponding to code data for each of a plurality of characters. The ROM 25 classifies dot pattern data for printing for each of a plurality of characters for printing characters such as alphabetic characters and symbols for each typeface (Gothic typeface, Mincho typeface, etc.). Six types of print character sizes (16, 24, 32, 48, 64, and 96 dot sizes) are stored corresponding to the code data. The ROM 25 also stores graphic pattern data for printing a graphic image.

  The ROM 26 reads a display drive control program for controlling the LCDC 28 described later corresponding to character code data such as characters and numbers inputted from the character input key 2 and data of the print buffer 272 described later to read the thermal head 9 and the like. A program for executing each process such as a print drive control program for driving a tape feed motor 30 to be described later is stored.

  The RAM 27 is provided with a text memory 271, a print buffer 272, a line print dot number memory 273, a total print dot number memory 274, a pixel memory 275, a print number memory 276, and the like. The text memory 271 stores character data input from the character input key 2. In the print buffer 272, dot patterns for printing such as a plurality of characters and symbols, the number of applied pulses that are the amount of energy for forming each dot, and the like are stored as dot pattern data. The line print dot number memory 273 stores a count value of the number of print dots for one line printed by the thermal head 9. The total print dot number memory 274 stores the total print dot number from the start of printing by the thermal head 9. The pixel memory 275 stores coordinate data of extracted pixels, which will be described later. The number of printed sheets memory 276 stores the number of printed sheets of paper, which is the printing medium, counted by the number of printed sheets sensor 32.

  The input / output interface 23 includes a keyboard 6, the thermistor 13, a display controller (hereinafter referred to as LCDC) 28, a drive circuit 29 for driving the thermal head 9, a drive circuit 31 for driving the tape feed motor 30, and printing. A number sensor 32 and the like are connected to each other. The thermistor 13 detects the temperature of the thermal head 9. The LCDC 28 has a video RAM 281 for outputting display data to the LCD 7. The print number sensor 32 detects the number of printed sheets. When characters or the like are input through the character keys of the keyboard 6, the text (document data) is sequentially stored in the text memory 271, and the keyboard 6 is controlled based on the dot pattern generation control program and the display drive control program. A dot pattern corresponding to a character or the like input via the screen is displayed on the LCD 7. The thermal head 9 is driven via the drive circuit 29 to print the dot pattern data stored in the print buffer 272, and the tape feed motor 30 performs tape feed control via the drive circuit 31 in synchronism with this. .

  The printing process executed by the CPU 21 will be described with reference to the flow of FIG. This process is realized by the CPU 21 executing a program stored in the ROM 26. The CPU 21 initializes the data stored in each memory of the RAM 27 (S11), and sets the value of the variable N indicating the number of prints stored in the print number memory 276 to 0 (S13). Next, it is determined whether or not an instruction for changing the background has been given via the keyboard 6 (S15). When it is determined that an instruction to change the background has been made (S15: YES), the background image is changed by the graphic pattern data stored in the ROM 25 (S17), and a variable N indicating the number of prints is set to 0 (S19). Proceed to step S57.

  On the other hand, if it is determined in step S15 that an instruction to change the background has not been given (S15: NO), it is determined whether or not a character is input from the character input key 2 (S21). If it is determined that a character has been input (S21: YES), character data is created using the dot pattern data stored in the ROM 25 (S23) and stored in the text memory 271 (see FIG. 2). Next, a variable N indicating the number of prints is set to 0 (S25), and the process proceeds to step S57. On the other hand, if it is determined in step S21 that no character has been input (S21: NO), it is determined whether or not an instruction for data processing for correcting the contour of the character has been issued via the return key 4 (S27). If it is determined that the data processing instruction has been issued (S27: YES), the print data processing shown in FIG. 4 is performed (S29). Next, the print data processed in the print data processing is transmitted to the text memory 271 (S50), and the process proceeds to step S57. On the other hand, if it is determined that the data processing instruction has not been given (S27: NO), other processing such as internal data change is executed according to the instruction from the user (S53), and the value of the variable N indicating the number of prints is set to zero. (S55), the process proceeds to step 57.

  The print data processing performed in step S29 in FIG. 3 will be described with reference to the flow in FIG. This process is realized by the CPU 21 executing a program stored in the ROM 26. A background pixel means a pixel constituting a background image. A contour pixel is a pixel that is a character pixel and one of the adjacent upper, lower, left, and right pixels is a background pixel. The CPU 21 first determines whether or not character data is stored in the text memory 271 (S31). If it is determined that character data is not stored (S31: NO), the process is terminated, and the step of FIG. Return to S29. On the other hand, when it is determined that character data is stored (S31: YES), a contour pixel extraction process, which is a process of extracting a contour pixel from the character pixels constituting each character, is performed (S33).

  With reference to the flow of FIG. 5, the outline pixel extraction process executed in step S33 of FIG. 4 will be described. This process is realized by the CPU 21 executing a program stored in the ROM 26. First, the CPU 21 extracts character pixels constituting each character based on the character data stored in the text memory 271 (S331), and stores it in the pixel memory 275. Next, it is determined whether or not all of the pixels above, below, left, and right with respect to one of the character pixels stored in the pixel memory 275 are character pixels (S333). For example, with respect to the character pixel L shown in FIG. 6A, the pixel L5 above the character pixel L, the pixel L6 on the right side of the character pixel L, the pixel L7 below the character pixel L, and the character pixel It is determined whether or not all of the pixels L8 on the left side of L are character pixels. This determination is made by collating the coordinates of the pixel L5, the coordinates of the pixel L6, the coordinates of the pixel L7, and the coordinates of the pixel L8 with the coordinates of the character pixel.

  When at least one of the upper, lower, left, and right pixels adjacent to the extracted character pixel is a background pixel (S333: NO), the extracted character pixel is set as a contour pixel (S335), and the coordinates are stored in the text memory 271. Then, the process proceeds to Step 337. On the other hand, if it is determined in step S333 that all the adjacent pixels in the vertical and horizontal directions are character pixels (S333: YES), the process proceeds to step S337. For example, in the character pixel L shown in FIG. 6A, since the pixel L5 and the pixel L8 are not character pixels, the pixel L is set as a contour pixel and stored in the pixel memory 275. The CPU 21 determines whether or not all the character pixels have been extracted (S337). That is, the CPU 21 determines whether or not all the pixels on the top, bottom, left and right are character pixels with respect to all the character pixels constituting each character. It is determined whether or not. This determination is made based on the coordinates of the character pixel. If it is determined that extraction of all character pixels is not completed (S337: NO), the process returns to step S331, and steps S331 to S337 are repeated until all character pixels are extracted. On the other hand, when it determines with having performed with respect to all the character pixels (S337: YES), a process is complete | finished and it returns to step S33 of FIG. Next, in FIG. 4, the coordinates of the contour pixel set in step S335 of FIG. 5 and stored in the pixel memory 275 are read from the pixel memory 275 (S35), and the process proceeds to the adjacent pixel correction process 1 in step S37.

  The adjacent pixel correction process 1 will be described with reference to the flow of FIG. In the following description, the transport direction of the print medium is referred to as a downstream direction, and the direction opposite to the transport direction of the print medium is referred to as an upstream direction. As shown in FIG. 6A, the CPU 21 extracts the coordinates (Xn−1, Yn) of the first adjacent pixel A1 adjacent to the contour pixel R1 (Xn, Yn) (S371). The first adjacent pixel is a pixel that constitutes the background image and is adjacent to the contour pixel. Next, it is determined whether or not the pixel C1 (X-2, Yn) in the downstream direction of the first adjacent pixel A1 is a contour pixel (S373). This determination is performed by collating the coordinates of the pixel C1 with the coordinates of the contour pixel stored in the pixel memory 275. Here, since the pixel C1 is not a contour pixel (S373: NO), only the color of the first adjacent pixel A1 is set to white (S383). Further, since the adjacent pixel of the contour pixel R1 includes the first adjacent pixel A2 (S381: NO), the coordinates (Xn, Yn + 1) of the first adjacent pixel A2 are also extracted (S371). Since the pixels in the downstream direction of the first adjacent pixel A2 are not contour pixels (S373: NO), only the first adjacent pixel A2 is set to white (S383). The first adjacent pixel A2 is a common first adjacent pixel for the contour pixel R1 and the contour pixel R2, but the processing for the first adjacent pixel A2 is performed by each of the contour pixel R1 and the contour pixel R2. And

  On the other hand, when the coordinates (Xn + 1, Yn) of the first adjacent pixel A4 adjacent to the contour pixel R3 (Xn, Yn) are extracted (S371), the pixel in the downstream direction of the first adjacent pixel A4 is the contour pixel R3. (S373: YES), the coordinates (Xn + 2, Yn) of the pixel B1 in the upstream direction of the first adjacent pixel A4 (hereinafter referred to as “second adjacent pixel”) are extracted (S375). Here, the second adjacent pixel is a pixel adjacent to the first adjacent pixel, but not adjacent to the contour pixel. Next, the color tone of the first adjacent pixel A4 is set to white (S377), the color tone of the second adjacent pixel B1 is set to white (S379), and the process proceeds to step S381. Further, the pixels adjacent to the contour pixel R3 include the first adjacent pixel A3 (Xn, Yn + 1), and the pixel C2 (Xn-1, Yn + 1) in the downstream direction of the first adjacent pixel A3 is not a contour pixel (S373). : NO), the color tone of only the first adjacent pixel A3 is set to white (S383), and the process proceeds to step S381.

  In step 381, it is determined whether all the first adjacent pixels have been extracted (S381). This determination is made based on the coordinates of the first adjacent pixel. If all the first adjacent pixels have not been extracted (S381: NO), the process returns to step S371, and steps S371 to S383 are repeated until all the first adjacent pixels are extracted. On the other hand, if it is determined that all the first adjacent pixels have been extracted (S381: YES), the process ends, the process returns to step S37 in FIG. 4, and the process proceeds to step S39. By performing the adjacent pixel correction process 1, as shown in FIG. 6B, the background pixel in the downstream direction of the contour pixel is equivalent to one pixel (for example, the first adjacent pixel A1 and the first adjacent pixel). Only pixel A2) is set to white. On the other hand, the background pixels in the upstream direction of the contour pixels are set to white for only two pixels (for example, the first adjacent pixel A4 and the second adjacent pixel B1).

  In step S39 of FIG. 4, it is determined whether or not all the contour pixels have been extracted. If it is determined that all the contour pixels have not been extracted (S39: NO), the process returns to step S35, and all the contour pixels are determined. Steps S35 to S39 are repeated until extraction. On the other hand, if it is determined that all the contour pixels have been extracted (S39: YES), the background image and the character data are combined and stored in the print buffer 272 (S41), and the process returns to step S29 in FIG. The process of S50 is performed, and the process proceeds to step S57.

  In step S57, it is determined whether or not there is a print instruction via the return key 4. If there is a print instruction (S57: YES), the print data is read from the print buffer 272 and printed (S59). 1 is added to N (S61), and the process proceeds to step 63. On the other hand, if there is no print instruction (S57: NO), the process returns to step S15 and the process is repeated. In step 63, it is determined whether or not there is an instruction to end the printing process by operating the keyboard 6 by the user. If the CPU 21 determines that an end instruction has been given (S63: YES), the process ends. On the other hand, if it is determined that there is no termination instruction (S63: NO), the process returns to step S15 and the process is repeated.

  As described above, in the printing apparatus 1 according to the first embodiment, even when the thermal head 9 stores heat, a white region that does not need to apply heat to the thermal head 9 during printing is set. In the white region, the thermal head 9 is cooled. Therefore, color mixing that occurs at the boundary between the background and the characters can be prevented. Furthermore, in the background pixels located in the upstream direction where color mixing is likely to occur, the number of pixels corresponding to the width for converting the color tone to white is increased. This can more reliably prevent color mixing that occurs at the boundary between the character and the background.

  Next, a printing apparatus according to the second embodiment of the present invention will be described. The CPU of the printing apparatus according to the second embodiment executes the adjacent pixel correction process 2 in S37 of the print data process in FIG. The adjacent pixel correction process 2 changes the number of background pixels to be white based on the temperature of the thermal head 9 and the number of printed sheets. The external configuration and electrical configuration of the printing apparatus according to the second embodiment are the same as those of the first embodiment.

  The adjacent pixel correction process 2 executed by the CPU will be described with reference to the flow of FIG. This process is realized by the CPU executing a program stored in the ROM 26. As shown in FIG. 9A, the CPU extracts the coordinates (Xn−1, Yn) of the first adjacent pixel A1 adjacent to the contour pixel R (Xn, Yn) (S400), and sets the first adjacent pixel A1. The color tone is set to white (S401) and stored in the pixel memory 275. Next, the temperature of the thermal head 9 is detected by the thermistor 13 to determine whether or not the temperature of the thermal head 9 is 65 ° C. or higher (S402), and when it is determined that the temperature is 65 ° C. or higher (S402). : YES), the process proceeds to step S407. On the other hand, when it is determined that the temperature is less than 65 ° C. (S402: NO), the value of the variable N indicating the number of printed sheets counted by the number-of-printed-number sensor 32 (see FIG. 2) and stored in the number-of-printed-number memory 276 is 3 or more. It is determined whether or not there is (S403). If the value of N is less than 3 (S403: NO), the process proceeds to step S405. On the other hand, if the value of N is 3 or more (S403: YES), the process proceeds to step S407.

  In step S407, as shown in FIG. 9A, the coordinates (Xn-2, Yn) of the second adjacent pixel B1 adjacent to the first adjacent pixel A1 in the downstream direction are extracted (S407), and the extracted second adjacent The color tone of the pixel B1 is set to white and stored in the pixel memory 275 (S408). Next, it is determined whether all the second adjacent pixels have been extracted (S409). For example, in FIG. 9A, since there is a second adjacent pixel B2 adjacent to the first adjacent pixel A1 (S409: NO), the process returns to step S407, and steps S407 to S409 are executed. On the other hand, if it is determined that all the second adjacent pixels have been extracted (S409: YES), the process proceeds to step S405.

  In step S405, it is determined whether all the first adjacent pixels have been extracted. If it is determined that all the first adjacent pixels have not been extracted (S405: NO), the process returns to step S400, and all the first adjacent pixels have been extracted. Steps S400 to S405 and steps S407 to S409 are repeated until one adjacent pixel is extracted. On the other hand, when it is determined that all the first adjacent pixels have been extracted (S405: YES), the process returns to step S37 in FIG. By performing the adjacent pixel correction process 2, as shown in FIG. 9B, two background pixels (first adjacent pixel A1, second adjacent pixel B1, and first adjacent pixel) among the background pixels adjacent to the contour pixel. The color tone is set to white only by A2 and the second adjacent pixel B2).

  As described above, in the printing apparatus according to the second embodiment, the number of pixels corresponding to the width for converting the color tone to white is calculated according to the temperature of the thermal head 9. When the temperature of the thermal head 9 is high, color mixing tends to occur at the boundary between the character and the background. Therefore, in the second embodiment, when the temperature of the thermal head 9 is high, the number of pixels corresponding to the width for converting the color tone to white is increased. This prevents color mixing that occurs at the boundary between the character and the background. Moreover, the temperature of the thermal head 9 becomes high by continuous printing. Therefore, in the second embodiment, when the number of printed sheets exceeds a predetermined number, the number of pixels corresponding to the width that makes the color tone white is increased. This prevents color mixing that occurs at the boundary between the character and the background.

  The present invention is not limited to the first and second embodiments, and various modifications can be made. For example, in the flow of FIG. 8, when the temperature satisfies 65 degrees or more (S402: YES) and the number of printed sheets satisfies 3 or more (S403: YES), up to the second adjacent pixel extracted in the background pixel Is also set to white. However, the present invention is not limited to this, and any temperature or any number of printed sheets may be used. Further, although the number of pixels for setting the color tone to white is 1 pixel or 2 pixels, the present invention is not limited to this, and the color tone of an arbitrary number of pixels may be set to white.

  In the above embodiment, the printing apparatus 1 shown in FIG. 1 has been described as the “print data processing apparatus” of the present invention, but it may be a PC (personal computer) connected to the printing apparatus or a single apparatus. .

  In the above description, the CPU 21 that executes step S33 of FIG. 4 is an example of “image extracting means”. The CPU 21 that executes Step S377, Step S379, and Step S383 in FIG. 7 and the CPU that executes Step S401 and Step S408 in FIG. 8 are examples of “color tone conversion unit”. The thermistor 13 shown in FIG. 2 is an example of “temperature detection means”, and the CPU that executes Step S402: YES in FIG. 8 and S407 is an example of “first calculation means”. The print number sensor 32 shown in FIG. 2 is an example of “counting means”, and the CPU that executes Step S403: YES in FIG. 8 and S407 is an example of “second calculation means”.

1 Printing Device 9 Thermal Head 13 Thermistor 21 CPU
26 ROM
27 RAM
32 Print number sensor

Claims (5)

Image data for printing a character on a print medium using a thermal printer, the image data including character pixels constituting the character and background pixels constituting the background of the character, the background pixel and the boundary are defined. Pixel extracting means for extracting the character pixel at a position to be formed as a contour pixel;
A print data processing apparatus comprising: a color tone conversion unit that converts the color tone of the background pixel to white with a width of at least one pixel along the contour pixel extracted by the pixel extraction unit. Temperature detecting means for detecting the temperature of a thermal head provided in the thermal printer;
In accordance with the detection result of the temperature detection unit, the color tone conversion unit includes a first calculation unit that calculates the number of pixels corresponding to a width for converting the color tone of the background pixel to white,
2. The print data processing apparatus according to claim 1, wherein the color tone conversion unit converts the color tone of the background pixel into white with a width of the number of pixels calculated by the first calculation unit.   When the print medium feeding direction at the time of printing by the thermal printer is the downstream direction, and the opposite direction is the upstream direction, the color tone conversion means sets the color tone of the background pixel located in the upstream direction of the contour pixel to white. 3. The print data processing according to claim 1, wherein the number of pixels corresponding to the width to be converted into the number of pixels is greater than the number of pixels corresponding to the width in which the color tone of the background pixel located in the downstream direction is converted to white. apparatus. Counting means for counting the number of printed sheets printed by the thermal printer;
According to the counting result of the counting means, the color tone conversion means comprises second calculation means for calculating the number of pixels corresponding to the width for converting the color tone of the background pixels to white,
4. The print data processing apparatus according to claim 1, wherein the color tone converting unit converts the color tone of the background pixel into white with a width of the number of pixels calculated by the second calculating unit. 5. Image data for printing a character on a print medium using a thermal printer, the image data including character pixels constituting the character and background pixels constituting the background of the character, the background pixel and the boundary are defined. A pixel extraction step of extracting the character pixel at a position to be formed as a contour pixel;
In the pixel extraction step, a print data processing program causing a computer to execute a color tone conversion step of converting the color tone of the background pixel to white with a width of at least one pixel along the extracted outline pixel.

Images