JP6615038B2 - Thermal transfer printer and control method thereof - Google Patents

Description

  The present invention relates to a thermal transfer printer and a control method therefor, and more particularly, to a technique for preventing background contamination in which ink is transferred to a position on printing paper that is not based on printing data.

  A sublimation color thermal transfer printer applies heat from a thermal head to an ink sheet, and sublimates the ink by the heat to print an image on a printing paper. Some sublimation color thermal transfer printers use an ink sheet (ink film) in which ink regions of each color of yellow (Y), magenta (M), and cyan (C) are arranged in order in the transport direction. Such a thermal transfer printer forms a color image by overlapping each color ink on the same printing area on the printing paper.

  The maximum size of the print area by the thermal transfer printer is limited to the size of each ink area arranged on the ink sheet, that is, the length of each ink area. On the other hand, when printing an image smaller than the size of each ink area, for example, one sheet of L size (L size) is formed using an ink sheet having an ink area capable of printing a maximum of 2 L size (2 L size). When printing, only half of the Y, M, and C color ink areas are used for printing. In other words, the remaining half of the ink area is not used, and ink use efficiency is poor. Therefore, as a printing method for improving the use efficiency of ink, a method of printing two L-size images from a 2L-size ink region is known. In the printing method, first, the first L-size image is printed using the first half area located on the ink sheet winding side of each ink area. Next, once the ink sheet is rewound, the unused area of the ink area used in the previous printing, that is, the second half area located on the ink sheet supply side of each ink area, is used for the second L size. Print the image. According to the printing method as described above, two screens (two sheets) of an L size image can be printed from a set of ink regions of Y, M, and C.

  On the other hand, the following problems also exist in the above printing method. The thermal transfer printer prints the first (1/2) sheet of the second sheet, and then once removes the thermal head from the ink sheet and rewinds the ink sheet. When printing the second sheet (2/2 sheet), the thermal transfer printer brings the thermal head into contact with the ink sheet again. At this time, the first half area of the ink area used for the printing of the ½ sheet is immediately before the ink use start position for printing the second sheet, that is, on the side of the ink sheet winding direction from the second half area. Exists. Since the used first half area is damaged by the thermal energy applied from the thermal head, the ink sheet in the vicinity of the printing start position of the 2 / 2nd sheet cannot obtain an appropriate tension. Wrinkles are likely to occur.

  Therefore, in Patent Document 1, the ink on the ink sheet supply side (second half area) in the ink area is used for the 1/2 sheet print, and the ink sheet is wound in the ink area for the 2/2 sheet print. A printer is disclosed that suppresses the occurrence of wrinkles that occur in the vicinity of the ink use start position of the second-second sheet by using the side (first half region) ink. Further, Patent Document 2 predicts the degree of damage of an ink sheet after printing a 1/2 sheet based on the density of the entire image to be printed on the 1/2 sheet and the average gradation of the entire image. A sublimation printer printing control method is disclosed that determines whether the ink used for the 1/2 sheet printing is on the ink sheet winding side or the ink sheet supply side of the ink region. As described above, both of Patent Document 1 and Patent Document 2 disclose means for reducing print flaws that occur when printing is performed using half of the ink area provided in the ink sheet.

JP 2004-202941 A JP 2007-090897 A

  In addition to the problems described above, a thermal transfer printer that prints using an ink sheet in which a plurality of colors of ink are arranged in an ink region for each color also has the following problems. In the printing operation, the thermal transfer printer transfers the ink of the first color ink area to the printing paper, then conveys the ink sheet, and determines the ink use start position of the second color ink area and the position of the heating element of the thermal head. Match. This operation is referred to as a cueing operation. During the cueing operation, the thermal transfer printer transports the printing paper in the opposite direction to the printing area in order to transfer the second color to the same printing area as the printing area where the first color was transferred, and starts printing in the printing area. Align the position with the heating element of the thermal head. This operation is referred to as a pull back operation. When the length of the print area is shorter than the length of one ink area, the cueing operation of the ink sheet may continue even after completion of the photographic paper pull-back operation. As a result, the ink sheet and the printing paper rub against each other, and the ink is transferred to a certain position on the printing paper that is not based on the printing data. In this specification, the problem that ink is transferred to a certain position on the printing paper that is not based on the printing data is referred to as background smudge.

  The present invention has been made in order to solve the above-described problems, and the ink sheet and the printing paper are rubbed against each other, thereby suppressing the background stains where the ink is transferred to a position not based on the printing data on the printing paper. An object is to provide a thermal transfer printer.

  A thermal transfer printer according to the present invention is a thermal transfer printer that performs color printing by transferring an image of each color to a printing area on a printing paper, and a plurality of colors of ink are provided for each color in a plurality of ink areas divided in the transport direction. And a control unit configured to control conveyance of the arranged ink sheets and conveyance of the printing paper, and the plurality of ink areas include a first ink area including ink used for the first printing to the printing area, and a first ink area. And a second ink area containing ink used for the second printing to the printing area performed after the printing, and the control means performs the second printing from the ink use end position in the first ink area used for the first printing. For printing from the cue time required to transport the ink sheet to the ink use start position in the second ink area used for the printing, from the first print end position in the print area to the second print start position in the print area Time difference obtained by subtracting the pullback time required for conveying the can, so that within a predetermined specified value, controls the beginning time or pull back time.

  According to the thermal transfer printer of the present invention, it is possible to provide a thermal transfer printer that suppresses the background stains where the ink sheet and the printing paper rub against each other and the ink is transferred to a position not based on the printing data on the printing paper.

1 is a diagram illustrating a configuration of a thermal transfer printer in Embodiment 1. FIG. 2 is a diagram illustrating a configuration of an ink sheet and printing paper used by the thermal transfer printer according to Embodiment 1. FIG. FIG. 6 is a diagram illustrating a change in the conveyance speed of a printing paper and a change in the conveyance speed of an ink sheet during a printing operation of the thermal transfer printer according to the first embodiment. 3 is a flowchart illustrating a control method of the thermal transfer printer in the first embodiment. FIG. 10 is a diagram illustrating a change in the conveyance speed of a printing paper and a change in the conveyance speed of an ink sheet during a printing operation of the thermal transfer printer according to the second embodiment.

  Embodiments of a thermal transfer printer according to the present invention will be described below with reference to the drawings.

<Embodiment 1>
The thermal transfer printer according to the first embodiment is an image forming apparatus, and uses an ink sheet including an ink area of a predetermined size (for example, 2 L size) to print to a print area (for example, L size) less than the predetermined size. To do. At that time, the thermal transfer printer calculates and compares the time difference between the time required for the cueing operation of the ink sheet and the time required for the retraction operation of the printing paper. Then, the thermal transfer printer controls the printing operation so that the time difference is within a predetermined range so that the background is not smeared in the printing paper pull-back operation.

(Configuration of thermal transfer printer)
FIG. 1A is a diagram illustrating an outline of the configuration of the thermal transfer printer 100 according to the first embodiment. The thermal transfer printer 100 includes a thermal head 3 having a plurality of heating elements in the width direction of the printing paper 2 a and a platen roller 4 that presses the printing paper 2 a and the ink sheet 1 between the thermal head 3 during printing. The platen roller 4 is connected to driving means (not shown). By the driving means, the platen roller 4 is configured to be able to move the ink sheet 1 and the printing paper 2a to a position where they can be pressed against or retracted between the thermal head 3 and the platen roller 4 according to a printing operation. .

  The thermal transfer printer 100 further includes a grip roller 5 and a pinch roller 6 that convey the printing paper 2 a drawn from the roll paper 2 to the thermal head 3. Further, the thermal transfer printer 100 includes a drive source for the grip roller 5 and a printing paper transport control unit 7a. The drive source for the grip roller 5 is not shown. The photographic paper conveyance control unit 7a controls the conveyance speed of the photographic paper 2a by connecting to the drive source and controlling the rotational drive of the grip roller 5. The drive source of the grip roller 5 is, for example, a stepping motor. Switching of the conveyance speed of the printing paper 2a by the rotational driving of the stepping motor is performed, for example, by the printing paper conveyance control unit 7a specifying a predetermined number of stages in the speed table. The speed table is stored in advance in a memory provided in the thermal transfer printer 100.

  The thermal transfer printer 100 also includes an ink sheet supply unit 8a that supplies the ink sheet 1 between the thermal head 3 and the platen roller 4, an ink sheet take-up unit 8b that collects the supplied ink sheet 1, and an ink sheet supply. An ink sheet conveyance control unit 7b that is connected to the unit 8a and the ink sheet winding unit 8b to control conveyance of the ink sheet 1; The thermal transfer printer 100 further includes a cutter 9 for cutting the printing paper 2a after printing.

  FIG. 1B is a functional block diagram of the thermal transfer printer 100. The thermal transfer printer 100 according to the first embodiment further includes a control unit 7 that is connected to the printing paper conveyance control unit 7a and the ink sheet conveyance control unit 7b and controls each of them. The thermal transfer printer 100 includes a thermal head control unit 7 c that controls heating of the thermal head 3. That is, the control unit 7 controls the thermal head control unit 7c based on the print data input from the outside to heat the thermal head 3. When the control unit 7 has both the function of the printing paper conveyance control unit 7a and the function of the ink sheet conveyance control unit 7b, the thermal transfer printer 100 does not necessarily include both the printing paper conveyance control unit 7a and the ink sheet conveyance control unit 7b. There is no need to prepare. In this case, the control unit 7 is connected to the grip roller 5 to control the conveyance of the printing paper 2a, and further connected to the ink sheet supply unit 8a and the ink sheet take-up unit 8b to control the conveyance of the ink sheet 1. As described above, the control unit 7 comprehensively controls the printing operation.

  FIG. 1C is a diagram illustrating a configuration of a processing circuit included in the thermal transfer printer. The functions of the control unit 7, the printing paper conveyance control unit 7a, the ink sheet conveyance control unit 7b, and the thermal head control unit 7c are realized by a processing circuit provided in the thermal transfer printer 100. The processing circuit included in the thermal transfer printer 100 includes a CPU (Central Processing Unit) 7d and a memory 7e connected to each other, and the processing circuit executes a program stored in the memory 7e by the CPU 7d. That is, each function of the control unit 7, the printing paper conveyance control unit 7a, the ink sheet conveyance control unit 7b, and the thermal head control unit 7c is described in a program, and the program is stored in the memory 7e as software or firmware. The CPU 7d reads and executes the program as appropriate, thereby realizing the functions of the control unit 7, the printing paper conveyance control unit 7a, the ink sheet conveyance control unit 7b, and the thermal head control unit 7c. Note that the memory 7e is, for example, a volatile or nonvolatile semiconductor memory such as a RAM or a flash memory.

  The processing circuit included in the thermal transfer printer 100 may be dedicated hardware. In this case, the processing circuit is, for example, a programmed processor. The thermal transfer printer 100 may realize each control by including a plurality of dedicated hardware in each function of the control unit 7, the printing paper conveyance control unit 7a, the ink sheet conveyance control unit 7b, and the thermal head control unit 7c. And by providing one dedicated hardware, each function of each part may be realized collectively. In addition, some of the functions of the control unit 7, the printing paper conveyance control unit 7a, the ink sheet conveyance control unit 7b, and the thermal head control unit 7c are realized by dedicated hardware, and some of the functions are software or firmware. It may be realized with.

(Ink sheet configuration)
FIG. 2A is a plan view showing the configuration of the ink sheet 1 used by the thermal transfer printer 100, and shows a state before the ink on the ink sheet 1 is transferred to the printing paper 2a, that is, before the ink is used. In the ink sheet 1, a plurality of colors of ink are arranged for each color in a plurality of ink regions 10 partitioned in the transport direction. In order from the winding direction side of the ink sheet 1 by the ink sheet winding unit 8b (winding direction side in FIG. 2A), each ink region 10 has yellow (Y) ink and magenta (M) ink. , Cyan (C) ink and overcoat (OP) are arranged. In addition, the ink sheet 1 uses four ink regions in which Y, M, C, and OP are arranged as a set of color inks, and the set of color inks is periodically arranged in the transport direction of the ink sheet 1. Have a configuration. Note that the OP has a function of covering the surface of the printing paper 2a after each color is transferred and protecting the surface of the printing paper 2a.

  In the first embodiment, among the plurality of arranged ink regions 10, the ink region in which Y ink is arranged is the first ink region 10a, and the ink region in which M ink is arranged is the second ink region 10b. Called. The first ink region 10a is located closer to the winding direction of the ink sheet 1 than the second ink region 10b. Note that the color of the ink provided in each of the first ink region 10a and the second ink region 10b is not limited to the above. Further, the length of each ink region 10 may have a predetermined value that differs for each ink color. The value may be stored in advance in the thermal transfer printer 100 used, or may be read from the ink sheet 1 by the control unit 7 of the thermal transfer printer 100 during use. That is, the thermal transfer printer 100 according to the first embodiment can use ink sheets having ink regions of various lengths. The ink is, for example, a dye or a pigment. Each ink region 10 is formed by, for example, applying each ink to the ink sheet 1.

(Operation of thermal transfer printer)
FIG. 2C is a plan view showing the printing area 20 on the printing paper 2a on which the thermal transfer printer 100 performs printing. The thermal transfer printer 100 uses the ink sheet 1 described above to transfer an image of each color based on the print data to the print area 20 on the print paper 2a to perform color printing. Hereinafter, a printing operation of the thermal transfer printer 100 will be described with reference to FIGS. 1 and 2. The thermal transfer printer 100 supplies the printing paper 2 a and the ink sheet 1 between the thermal head 3 and the platen roller 4 when printing is performed. The printing paper 2a is conveyed from the roll paper 2 to the thermal head 3 by the rotation of the grip roller 5 under the control of the printing paper conveyance control unit 7a. At that time, the printing area 20 of the printing paper 2 a is temporarily conveyed in the direction of the cutter 9 after passing through the thermal head 3. Thereafter, the printing area 20 is conveyed in the reverse direction, that is, in the direction of the roll paper 2 from the cutter 9, and is printed when it passes through the thermal head 3 again. The conveyance direction of the printing paper 2a at the time of printing is assumed to be the conveyance direction at the time of printing as shown in FIG. At the time of printing, the ink sheet 1 is conveyed from the ink sheet supply unit 8a to the thermal head 3 by the ink sheet conveyance control unit 7b, and is wound and stored in the ink sheet winding unit 8b. The conveyance direction of the ink sheet 1 is shown as the winding direction in FIG. Note that the printing conveyance direction of the printing paper 2a shown in FIG. 1 and the winding direction of the ink sheet 1 correspond to the respective directions shown in FIG.

  The platen roller 4 presses the printing paper 2a and the ink sheet 1 between the thermal head 3 by the driving means (not shown) described above. In this state, the control unit 7 heats the heating elements of the thermal head 3 based on the input print data. The ink on the ink sheet 1 is sublimated by the heat, and an image based on the print data is transferred to the print area 20 of the print paper 2a. During the printing operation, the printing paper 2a is continuously conveyed in the printing conveyance direction shown in FIG. 1 by the control of the printing paper conveyance control unit 7a, and the ink sheet 1 is also taken up by the control of the ink sheet conveyance control unit 7b. Continue to be transported to. That is, the thermal transfer printer 100 transfers the ink in each ink area 10 to the printing area 20 of the printing paper 2a while conveying the ink sheet 1 and the printing paper 2a. Further, the thermal transfer printer 100 performs color printing by transferring Y, M, C, and OP to the same printing area 20 of the printing paper 2a. As will be described later, during each color printing operation, a pull-back operation for transporting the printing paper 2a in a pull-back direction opposite to the transport direction during printing and a cue-up operation accompanied by the transport of the ink sheet 1 are performed. During the retraction operation and cueing operation, the platen roller 4 is moved by the driving means to a position where it is retracted from the thermal head 3 so as not to hinder the conveyance of the printing paper 2a and the conveyance of the ink sheet 1. That is, the thermal transfer printer 100 releases the press-contact state between the thermal head 3 and the platen roller 4 during the pulling back operation and the cueing operation, and forms a clearance between them. Further, the thermal head 3 serves as a conveyance guide in the pulling back operation and the cueing operation.

  The thermal transfer printer 100 conveys the printing paper 2 a to the position of the cutter 9 after transferring each color to the printing area 20. The cutter 9 cuts the printing paper 2a to separate the printing region 20 from the printing paper 2a, and the thermal transfer printer 100 discharges the separated printing region 20 to the outside as a printed matter.

(Conveyance control of printing paper and ink sheet)
As described above, the thermal transfer printer 100 according to the first embodiment uses the ink sheet 1 to transfer an image of each color into the same printing area 20 on the printing paper 2a and perform color printing. The conveyance control of the printing paper 2a and the ink sheet 1 performed by the thermal transfer printer 100 when transferring the ink of each ink area 10 into the same printing area 20 will be described below. In the present invention, the print in which the thermal transfer printer 100 transfers the ink in the first ink region 10a located on the ink sheet winding direction side into the print region 20 is referred to as a first print. The control of the thermal transfer printer 100 by the control unit 7, the printing paper conveyance control unit 7a, and the ink sheet conveyance control unit 7b described below is realized by the CPU 7d executing a program stored in the memory 7e described above. .

  FIG. 2B is a plan view showing the state of the ink sheet 1 after the ink in the first ink region 10a is transferred in the first print. In addition, a print in which the ink in the second ink region 10b is transferred into the same print region 20 after the first print is referred to as a second print. In the first printing, the Y ink in the first ink region 10a is used from the ink use start position 11a to the ink use end position 12a. The length is equal to the length D1 of the print area 20 shown in FIG. For example, the ink use start position 11a is stored in advance in the thermal transfer printer 100, or the information is acquired by the control unit 7 from the ink sheet 1 to be used. The ink use end position 12a is determined based on the print data. In the first embodiment, the length D1 from the ink use start position 11a to the ink use end position 12a is the maximum usable ink length of the first ink region 10a, that is, in the transport direction of the first ink region 10a. Shorter than the length.

  In order to perform the second printing after the first printing, the printing paper transport control unit 7a prints the printing paper from the first printing end position 22 to the second printing start position 21 in the printing area 20 shown in FIG. 2a is conveyed. That is, the photographic paper conveyance control unit 7a conveys the photographic paper 2a so that the second printing start position 21 coincides with the position immediately below the heating element included in the thermal head 3. Since the second print of the first embodiment is performed in the print area 20 at the same position as the first print, the first print start position and the second print start position are equal, and the first print end position and the second print start position are the same. The print end position is also equal. In the present invention, the conveying operation of the printing paper 2a from the first printing end position 22 to the second printing start position 21 is referred to as a drawing-back operation of the printing paper 2a. Note that the conveyance direction of the printing paper 2a during the pull-back operation is shown in FIG. 1 as the pull-back direction. In FIG. 2C, the pullback direction is opposite to the conveyance direction during printing. In the first embodiment, the conveyance distance of the printing paper 2a during the pull-back operation, that is, the pull-back distance is equal to the length D1 of the print area 20. Further, in the first embodiment, the time required for the pull back operation is set as the pull back time T1.

  While the photographic paper conveyance control unit 7a performs the pull back operation of the photographic paper 2a, the ink sheet conveyance control unit 7b performs the ink use end position of the first ink region 10a shown in FIG. 2B for the second printing. The ink sheet 1 is conveyed from 12a to the ink use start position 11b of the second ink region 10b. That is, the ink sheet conveyance control unit 7b conveys the ink sheet 1 so that the position immediately below the heating element included in the thermal head 3 coincides with the ink use start position 11b. In the present invention, this conveyance operation is referred to as a cueing operation of the ink sheet 1, and a time required for the cueing operation is set as a cueing time T2. Further, the transport distance of the ink sheet 1 in the cueing operation, that is, the cue distance is a distance D2 from the ink use end position 12a of the first ink area 10a to the ink use start position 11b of the second ink area 10b. Therefore, the shorter the length D1 of the print region 20, the longer the cueing distance D2 of the ink sheet 1 in the cueing operation. The ink use start position 11b may be stored in the thermal transfer printer 100 in advance as in the ink use start position 11a, or the control unit 7 may acquire the information from the ink sheet 1 to be used. .

  FIG. 3A is a diagram showing a change in the conveyance speed of the printing paper 2a in the printing operation from the first printing to the second printing including the pulling back operation of the printing paper 2a. FIG. 3B is a diagram illustrating a change in the conveyance speed of the ink sheet 1 in the printing operation from the first printing to the second printing including the cueing operation of the ink sheet 1. In FIGS. 3A and 3B, the horizontal axis represents the conveyance time, the vertical axis represents the conveyance speed, and the area represents the conveyance distance. A solid line at the time of the pull-back operation in FIG. 3A represents a change in the conveyance speed of the printing paper 2a when the background stain occurs. 3A represents a change in the conveyance speed of the printing paper 2a according to the first embodiment to which the present invention, which is a means for improving background stains, is applied.

  First, the conveyance control represented by the solid line in the case where soiling occurs in FIG. In the first printing, the printing paper transport control unit 7a transports the printing area 20 from the first printing start position 21 to the first printing end position 22 by a distance D1. After the end of the first printing, the printing paper 2a is conveyed from the first printing end position 22 to the second printing start position 21 at a normal pulling speed V1 over a pulling time T1. As described above, since the first print start position 21 and the second print start position 21 are equal, the transport distance in the pull back operation, that is, the pull back distance is D1.

  Further, as shown in FIG. 3B, the ink sheet conveyance control unit 7b takes the cue time T2 at the normal cue speed V2 after the end of the first printing, and then in the first ink region 10a. The ink sheet 1 is conveyed from the ink use end position 12a to the ink use start position 11b of the second ink region 10b. This cue distance is D2 as described above.

  In this case, the cue time T2 of the ink sheet 1 is longer than the retraction time T1 of the printing paper 2a. Therefore, there is a possibility that the ink sheet 1 will rub against a certain position not based on the print data on the print paper 2a during the cueing operation (T2-T1) after the pull back operation is completed. When the rubbing occurs, the ink on the ink sheet 1 is unintentionally transferred to the printing paper 2a, resulting in background staining. Moreover, the occurrence frequency of the background stain increases as the time difference (T2-T1) increases. The condition for increasing the time difference (T2−T1) is when the cue time T2 is large and the pull back time T1 is small, which is from the ink use start position 11a to the ink use end position 12a in the first print. This is when the length D1 is short. That is, the smaller the print area 20 is smaller than the size of the ink area 10, the higher the occurrence frequency of background stains.

  Next, the conveyance control performed by the thermal transfer printer 100 according to the first embodiment of the present invention represented by a dotted line in FIG. 3A will be described. The controller 7 controls the pull back time T1 so that the time difference (T2−T1) between the cue time T2 and the pull back time T1 is within a predetermined value. In the first embodiment, the specified value is set to 0, and the control unit 7 prints the printing paper 2a from the first printing end position 22 to the second printing start position 21 when the time difference (T2-T1) is larger than 0. The pull-back speed V1 when transporting is reduced. In the present specification, a new pullback speed that is lower than the normal pullback speed V1 is referred to as V1 '. Further, the time required to complete the pull back operation at the new pull back speed V1 'is referred to as a new pull back time T1'. The control unit 7 calculates a new pullback speed V1 ′ so as to satisfy Expression 1 derived from the relational expression of (T2−T1 ′) ≦ 0. At this time, the pullback distance remains unchanged at D1. When a stepping motor is used as the drive source of the grip roller 5, the control unit 7 prepares a speed table of the stepping motor prepared in advance for the speed closest to the new pullback speed V1 ′ calculated from Equation 1. You may choose from.

  The control unit 7 outputs the new pullback speed V1 'calculated by Expression 1 to the printing paper transport control unit 7a. The printing paper transport control unit 7a transports the printing paper 2a from the first print end position 22 to the second print start position 21 at the new pull-back speed V1 'over a new pull-back time T1'.

  In the first embodiment, the control unit 7 controls the retraction speed V1 of the printing paper 2a in the retraction operation, while the indexing speed V2 by the ink sheet conveyance control unit 7b changes as shown in FIG. I won't let you. After completion of the first printing, the ink sheet conveyance control unit 7b takes the cueing time T2 at the normal cueing speed V2, and then the ink in the second ink region 10b from the ink use end position 12a in the first ink region 10a. The ink sheet 1 is conveyed to the use start position 11b. The conveyance distance, that is, the cueing distance is D2.

  The functions and operations of the control unit 7, the printing paper conveyance control unit 7a, and the ink sheet conveyance control unit 7b described above are described as a program and stored in a memory 7e included in the processing circuit. The program is executed by the CPU 7d included in the processing circuit. That is, in other words, the thermal transfer printer 100 performs ink from the ink use end position 12a in the first ink area 10a used for the first print to the ink use start position 11b in the second ink area 10b used for the second print. From the cue time T2 necessary for conveying the sheet 1, the pull-back necessary for conveying the printing paper 2a from the first printing end position 22 in the printing area 20 to the second printing start position 21 in the printing area 20 is performed. A processing circuit for controlling the pull back time T1 is provided so that the time difference (T2−T1) obtained by subtracting the time T1 is within a predetermined value. Further, when the time difference (T2−T1) obtained by subtracting the pull back time T1 from the cue time T2 is larger than the specified value, the thermal transfer printer 100 removes the printing paper 2a from the first printing end position 22 to the second printing. A processing circuit is provided that reduces the pull-back speed V1 of the printing paper 2a when transporting to the start position 21.

(effect)
In FIG. 3, as shown by the change in the conveyance speed of the printing paper 2a indicated by the dotted line, the timing for completing the cueing operation and the timing for completing the pull-back operation are synchronized. Therefore, the thermal transfer printer 100 according to the first embodiment does not continue the cueing operation after the pull back operation is completed, and thus can prevent background contamination. That is, even when the thermal transfer printer 100 prints on the print area 20 having a size smaller than that of the ink area 10, it is possible to obtain a print product with no background stain.

  Further, in the first embodiment, as shown in FIG. 3, the completion timing of the cueing operation and the completion timing of the retraction operation are synchronized, but the completion of the retraction operation is after the completion of the cueing operation. A new pullback speed V1 ′ may be set. Even in that case, soiling can be prevented.

  In summary, the thermal transfer printer 100 according to the first embodiment of the present invention is a thermal transfer printer 100 that performs color printing by transferring an image of each color to the printing area 20 on the printing paper 2a, and is divided in the transport direction. Control means (control unit 7) for controlling the conveyance of the ink sheet 1 in which a plurality of colors of ink are arranged for each color in the plurality of ink areas 10 and the conveyance of the printing paper 2a are provided. Includes a first ink area 10a containing ink used for the first printing on the printing area 20, and a second ink area 10b containing ink used for the second printing on the printing area 20 performed after the first printing. The controller 7 includes an ink use start position 11b in the second ink area 10b used for the second print from the ink use end position 12a in the first ink area 10a used for the first print. Required for transporting the printing paper 2a from the cue time T2 required for transporting the ink sheet 1 to the second print start position 21 in the print area 20 from the first print end position 22 in the print area 20. The pull back time T1 is controlled so that the time difference (T2−T1) obtained by subtracting the pull back time T1 is within a predetermined value. When the time difference (T2−T1) obtained by subtracting the pull back time T1 from the cue time T2 is larger than the specified value, the control unit 7 of the thermal transfer printer 100 removes the print paper 2a from the first print end position 22 to the first print end position 22. The pull-back speed V1 of the printing paper 2a when transporting to the 2-printing start position 21 is reduced. With the configuration described above, the thermal transfer printer 100 completes the pull-back operation after completion of the cueing operation, and therefore can prevent background contamination. That is, even when the thermal transfer printer 100 prints on the print area 20 having a size smaller than that of the ink area 10, it is possible to obtain a print product with no background stain.

  In recent years, thermal transfer printers have been put on the market that use an ink sheet in which ink regions having a predetermined size are arranged to print a printed matter having a size that is variously smaller than the ink region. In printing performed by such a thermal transfer printer, since the size of the printing area printed in one ink area in the ink sheet varies, the cue distance D2 of the ink sheet and the retraction distance D1 of the printing paper are also used. Many combinations will occur. The thermal transfer printer 100 according to the first embodiment of the present invention can suppress scumming even with such various combinations of the pullback distance D1 and the cueing distance D2. That is, the thermal transfer printer 100 provides a printed matter that is free from image defects such as background stains even when an image having a size smaller than the ink region 10 is printed using the ink sheet 1 having the ink region 10 having a predetermined size. Is possible.

  In addition, the thermal transfer printer 100 according to the first embodiment also prevents soiling while simultaneously performing the cueing operation and the pulling back operation. Therefore, the thermal transfer printer 100 according to the first embodiment does not increase the printing time as compared with the thermal transfer printer having a control method in which the pull-back operation is performed after completion of the cueing operation in order to avoid background contamination. Can prevent soiling. That is, the thermal transfer printer 100 according to the first embodiment can shorten the time for providing prints to the user and improve serviceability.

  In addition, in the conventional thermal transfer printer, in order to avoid rubbing between the ink sheet and the printing paper during the retraction operation, it is necessary to increase the retreat distance, that is, the clearance between the thermal head and the platen roller during the retraction operation. Since the thermal transfer printer 100 according to the first embodiment can reduce the contact between the ink sheet 1 and the printing paper 2a during the pull back operation, the clearance between the thermal head 3 and the platen roller 4 can be reduced. As a result, the thermal transfer printer 100 can reduce the size of the apparatus, which is useful for saving space when installed in a store, for example. Further, downsizing of the device size leads to cost reduction and resource saving by reducing the usage amount of the constituent members of the device.

(Control method of thermal transfer printer)
Next, a method for controlling the thermal transfer printer 100 according to the present invention will be described. The control method of the thermal transfer printer 100 according to the present invention is such that the control unit 7 controls the time difference (T2−T1) to be within a predetermined value before at least the second printing step for performing the second printing. A timing control step for controlling the cue time T2 or the pull back time T1 is provided. The control method for the thermal transfer printer 100 shown in the first embodiment includes a timing control step for controlling the pull-back time T1 before the first printing step for performing the first printing. The control method of the thermal transfer printer 100, that is, each step, by the control unit 7, the printing paper conveyance control unit 7a, and the ink sheet conveyance control unit 7b described below, is stored as a program in the memory 7e. The program is executed by the CPU 7d to realize each function.

  FIG. 4 is a flowchart illustrating a method in which the control unit 7 controls the pull back time T1 so that the time difference (T2−T1) between the cue time T2 and the pull back time T1 is within a predetermined value. First, print data is input to the control unit 7 from an external device such as a personal computer. Based on the print data, the control unit 7 calculates the length of the print region 20 and the use length of the ink in the first ink region 10a used in the first print, that is, the use length of the ink sheet 1 (step S1). . In the first embodiment, the length of the print area 20 and the length of the ink sheet used in the first print are the same as the length of the print area 20, and both are D1.

  Subsequently, the control unit 7 determines the distance from the ink use end position 12a in the first ink area 10a used for the first print to the ink use start position 11b in the second ink area 10b used for the second print, That is, the cueing distance D2 in the cueing operation of the ink sheet 1 is calculated (step S2). Details of the procedure for calculating the cue distance D2 will be described below. The ink use start position 11a in the first ink area 10a and the ink use start position 11b in the second ink area 10b shown in FIG. 2B are predetermined positions, and the position information is sent to the thermal transfer printer 100 in advance. May be stored, or the control unit 7 may acquire the position information from the ink sheet 1 to be used. The ink use end position 12a in the first ink region 10a is calculated by adding the ink use length D1 calculated in step S1 to the ink use start position 11a by the control unit 7. As described above, the distance from the ink use end position 12a in the first ink area 10a to the ink use start position 11b in the second ink area 10b, that is, the cueing distance D2 of the ink sheet 1 is calculated.

  Next, as shown in FIG. 4, the control unit 7 divides the cue distance D2 by the normal cue speed V2, and calculates a cue time T2 required for the cueing operation of the ink sheet 1 (step S3).

  Next, the control unit 7 calculates a distance from the first print end position 22 in the print area 20 to the second print start position 21 in the same print area 20, that is, a pull-back distance D1 in the pull-back operation of the printing paper 2a. In the first embodiment, the distance is equal to the length D1 of the print area 20. The controller 7 divides the pullback distance D1 by the normal pullback speed V1, and calculates a pullback time T1 required for the pullback operation of the printing paper 2a (step S4).

  The control unit 7 calculates a time difference (T2−T1) by subtracting the pullback time T1 calculated in step S4 from the cue time T2 calculated in step S3. Further, the control unit 7 determines whether or not the time difference (T2−T1) is within a predetermined value (step S5). In the first embodiment, the specified value is zero. That is, it is determined whether or not the cueing operation of the ink sheet 1 is continued after completion of the pulling-back operation of the printing paper 2a.

  When the time difference (T2−T1) is larger than 0 (No in step S6 in FIG. 4), the cueing operation of the ink sheet 1 continues even after the photographic paper 2a is pulled back. Therefore, during the cueing operation that continues even after completion of the pull-back operation, the ink sheet 1 rubs against one place on the printing paper 2a, that is, a certain position that is not based on the printing data, and stains occur. Therefore, the control unit 7 controls the pull-back time T1 so that the time difference (T2−T1) is within a predetermined value, that is, 0 or less. Specifically, the control unit 7 extends the pull-back time T1 by lowering the conveyance speed of the printing paper 2a in the pull-back operation, that is, the pull-back speed lower than the normal pull-back speed V1. Hereinafter, a method of calculating the pullback speed for extending the pullback time T1 will be described. In this specification, a new pullback speed in which the conveyance speed is lower than the normal pullback speed V1 is referred to as V1 ′, and the time required for performing the pullback operation at the pullback speed V1 ′ is a new pullback time. This is referred to as T1 ′. In order to set the time difference (T2−T1 ′) to 0 or less, the control unit 7 calculates a new pullback speed V1 ′ so as to satisfy the above formula 1. The controller 7 sets a new pull-back speed V1 'calculated according to Equation 1 in the photographic paper transport controller 7a (step S6).

  The control unit 7 is configured such that the printing paper conveyance control unit 7a performs the pulling back operation of the printing paper 2a at the new pulling back speed V1 ′, and the ink sheet conveyance control unit 7b further performs the ink sheet 1 at the normal cueing speed V2. It is decided to perform the cueing operation. The thermal transfer printer 100 performs the printing operation from the first printing step to the second printing step after performing the timing control step including steps S1 to S6 (step S7).

  In step S6, if the time difference (T2-T1) is equal to or less than 0 even if the pullback operation is performed at the normal pullback speed V1 (Yes in step S6 in FIG. 4), ink is returned after the pullback operation of the printing paper 2a is completed. The cueing operation of the sheet 1 does not continue and the background is not soiled. Therefore, in the control unit 7, the photographic paper transport control unit 7a performs the pull back operation of the photographic paper 2a at the normal pull back speed V1, and the ink sheet transport control unit 7b further performs the ink sheet transfer at the normal cueing speed V2. It is decided to perform 1 cueing operation. The thermal transfer printer 100 performs the printing operation from the first printing step to the second printing step after performing the timing control step including steps S1 to S6 (step S7).

(Effect of thermal transfer printer control method)
By the control method of the thermal transfer printer 100 as described above, the cueing operation of the ink sheet 1 of the thermal transfer printer 100 is completed at the same time as or before the completion of the pull-back operation of the printing paper 2a. Therefore, since the thermal transfer printer 100 does not continue the cueing operation after the pulling back operation is completed, it is possible to prevent background contamination. That is, even when the thermal transfer printer 100 prints on the print area 20 having a size smaller than that of the ink area 10, it can provide a print product with no background stain. In addition, the thermal transfer printer 100 according to the first embodiment shortens the printing time compared to other thermal transfer printers that have a control method that performs a pull-back operation after completion of the cueing operation in order to avoid scumming. While preventing soiling.

  The control method of the thermal transfer printer 100 is summarized as follows. In the control method of the thermal transfer printer 100 according to the first embodiment of the present invention, a plurality of colors of ink are colored in a plurality of ink regions 10 partitioned in the transport direction. A method of controlling the thermal transfer printer 100 that uses the ink sheets 1 arranged in the above-described manner to transfer an image of each color to the printing area 20 on the printing paper 2a to perform color printing, and includes a plurality of control means (control unit 7). A first printing step for performing the first printing on the printing area 20 using the ink of the first ink area 10a included in the ink area 10, and the control unit 7 includes the plurality of ink areas 10 after the first printing step. And a second printing step for performing a second printing on the printing area 20 using the ink in the second ink area 10b, and the control method of the thermal transfer printer 100 is at least a second printing. Prior to the step, the control unit 7 performs ink from the ink use end position 12a in the first ink area 10a used for the first print to the ink use start position 11b in the second ink area 10b used for the second print. From the cue time T2 necessary for conveying the sheet 1, the pull-back necessary for conveying the printing paper 2a from the first printing end position 22 in the printing area 20 to the second printing start position 21 in the printing area 20 is performed. There is further provided a timing control step for controlling the pull-back time T1 so that the time difference (T2−T1) obtained by subtracting the time T1 is within a predetermined value. The timing control step is performed when the control unit 7 conveys the printing paper 2a from the first printing end position 22 to the second printing start position 21 when the time difference (T2-T1) is larger than the specified value. The pull-back time T1 is extended by reducing the conveyance speed of the printing paper 2a. With the above configuration, the cueing operation of the ink sheet 1 included in the control method of the thermal transfer printer 100 is completed at the same time as or before the completion of the pulling-back operation of the printing paper 2a. Therefore, the control method of the thermal transfer printer 100 according to the first embodiment can prevent background contamination. That is, according to the control method described above, the thermal transfer printer 100 can obtain a print product free from background stain even when printing on the print region 20 having a size smaller than that of the ink region 10.

(Modification of Embodiment 1)
In the first embodiment, the specified value is 0, but the present invention is not limited to this. A new pull-back speed V1 ′ such that the time difference (T2−T1 ′) is equal to or less than the specified value t when the specified value is t is expressed by Equation 2.

  If the predetermined value t is set to a negative value in advance, the completion of the cueing operation of the ink sheet 1 is always completed earlier than the completion of the pulling-back operation of the printing paper 2a, which is effective in preventing the occurrence of background stains. .

<Embodiment 2>
In the first embodiment, when the time difference (T2−T1) obtained by subtracting the pull back time T1 from the cue time T2 is larger than the specified value, the control unit 7 performs control to reduce the pull back speed V1 of the printing paper 2a. In the second embodiment, when the time difference (T2-T1) is larger than the specified value, the control unit 7 performs control to increase the cue speed V2 and shorten the cue time T2. That is, the thermal transfer printer 100 according to the second embodiment stores, in the memory 7e, a program for increasing the cue speed V2 and shortening the cue time T2 when the time difference (T2-T1) is larger than a specified value. The CPU 7d includes a processing circuit that executes the program. Details of the second embodiment will be described below, but the description of the same configuration as that of the first embodiment will be omitted.

  FIG. 5A is a diagram illustrating a change in the conveyance speed of the printing paper 2a in the printing operation from the first printing to the second printing including the drawing back operation of the printing paper 2a. FIG. 5B is a diagram illustrating a change in the conveyance speed of the ink sheet 1 in the printing operation from the first printing to the second printing including the cueing operation of the ink sheet 1. A solid line at the time of the cueing operation in FIG. 5B represents a change in the conveyance speed of the ink sheet 1 when the background stain occurs. In addition, the dotted line at the time of the cueing operation in FIG. 5B represents a change in the conveyance speed of the ink sheet 1 in the second embodiment to which the present invention, which is a means for improving soiling, is applied.

  In FIG. 5B, the control unit 7 determines the time so that the time difference (T2−T1) between the cue time T2 and the pull back time T1 is within a predetermined value, and within 0 in the second embodiment. Control time T2. When the time difference (T2−T1) is greater than 0, the control unit 7 conveys the ink sheet 1 from the ink use end position 12a in the first ink area 10a to the ink use start position 11b in the second ink area 10b. The cueing speed V2 when increasing is increased. In this specification, a new cueing speed obtained by increasing the conveyance speed from the normal cueing speed V2 is referred to as V2 '. The time required for performing the cueing operation at the new cueing speed V2 'is referred to as a new cueing time T2'. The controller 7 calculates a new cueing speed V2 ′ from the relational expression (T2′−T1) ≦ 0 as in the first embodiment. Note that the cue distance does not change and is D2.

  The control unit 7 outputs the calculated new cueing speed V2 'to the ink sheet conveyance control unit 7b. The ink sheet conveyance control section 7b takes the new cueing time T2 ′ at the new cueing speed V2 ′ and removes the ink sheet 1 from the ink use end position 12a in the first ink region 10a to the second ink. The ink is conveyed to the ink use start position 11b in the area 10b.

  On the other hand, in the second embodiment, as shown in FIG. 5A, the pull back operation by the printing paper transport control unit 7a is not changed. After the end of the first printing, the printing paper transport control unit 7a transports the printing paper 2a from the first printing end position 22 to the second printing start position 21 at a normal pulling speed V1 over a pull-back time T1. The conveyance distance, that is, the pullback distance is D1.

  Further, regarding the control method of the thermal transfer printer 100 in the second embodiment, step S6 in the flowchart shown in FIG. 4 is changed. That is, instead of step S6, the control unit 7 calculates a cueing speed V2 'that satisfies the relational expression (T2'-T1) ≤0 and sets it in the ink sheet conveyance control unit (step S6'). Other steps are the same as those in FIG.

  As described above, the control unit 7 of the thermal transfer printer 100 according to the second embodiment of the present invention has a predetermined time difference (T2−T1) obtained by subtracting the pullback time T1 from the cue time T2. The cue time T2 is controlled so as to be within the specified value. When the time difference (T2-T1) is larger than the specified value, the control unit 7 moves the ink sheet 1 from the ink use end position 12a in the first ink area 10a to the ink use start position 11b in the second ink area 10b. The conveyance speed of the ink sheet 1 during conveyance is increased. With the configuration described above, the cueing operation of the ink sheet 1 performed by the thermal transfer printer 100 is completed at the same time as or before the completion of the pulling-back operation of the printing paper 2a. Therefore, the thermal transfer printer 100 can prevent soiling. In addition, since the controller 7 shortens the cue time T2, the printing time is shortened compared to the case where the conveyance speed of the printing paper 2a described in the first embodiment is reduced.

  Further, in the control method of the thermal transfer printer 100 according to the second embodiment of the present invention, at least before the second printing step, the control unit 7 subtracts the pull back time T1 from the cue time T2 ( There is further provided a timing control step for controlling the cue time T2 so that T2-T1) is within a predetermined value. Further, in the timing control step, when the time difference (T2−T1) is larger than the specified value, the control unit 7 moves the ink sheet 1 from the ink use end position 12a in the first ink region 10a to the second ink region 10b. The transport speed of the ink sheet 1 when transporting to the ink use start position 11b is increased. With the above configuration, the cueing operation of the ink sheet 1 included in the control method of the thermal transfer printer 100 is completed at the same time as or before the completion of the pulling-back operation of the printing paper 2a. Therefore, the control method of the thermal transfer printer 100 according to the second embodiment can prevent background contamination. In addition, since the controller 7 shortens the cue time T2, the printing time is shortened compared to the case where the conveyance speed of the printing paper 2a described in the first embodiment is reduced.

<Embodiment 3>
The thermal transfer printer 100 according to the third embodiment further includes a boundary detection sensor (not shown) that detects the boundary of each ink region 10 of the ink sheet 1. In the thermal transfer printer 100 or its control method shown in the second embodiment, if the controller 7 excessively increases the cueing speed V2 of the ink sheet 1, the boundary determination error of the boundary detection sensor becomes large. As a result, the positional accuracy when the ink sheet conveyance control unit 7b conveys the ink sheet 1 from the ink use end position 12a to the ink use start position 11b deteriorates. For example, when the ink sheet conveyance control unit 7b originally conveys the ink to the ink use start position 11b in the second ink region 10b, it conveys it to a certain position in the first ink region 10a due to an error of the boundary detection sensor. There is also a possibility. In this state, the thermal transfer printer 100 cannot print with the correct color based on the print data. Although it is possible to increase the length of each ink region 10 of the ink sheet 1 to avoid the error, such a measure leads to an increase in the cost of the ink sheet 1.

  Therefore, the control unit 7 of the thermal transfer printer 100 according to the third embodiment causes the pull back time T1 so that the time difference (T2−T1) obtained by subtracting the pull back time T1 from the cue time T2 is within a predetermined value. And the cue time T2 are controlled. That is, when the time difference (T2−T1) is larger than the specified value, the control unit 7 decreases the pull-back speed V1 of the printing paper 2a to extend the pull-back time T1, and the cue speed V2 of the ink sheet 1 Is increased to shorten the cue time T2. That is, the thermal transfer printer 100 according to the third embodiment stores a program for controlling both the pull back time T1 and the cue time T2 so that the time difference (T2−T1) is within a predetermined value. And a processing circuit for executing the program by the CPU 7d.

  Further, regarding the control method of the thermal transfer printer 100 according to the third embodiment, step S6 in the flowchart shown in FIG. 4 is changed. That is, the control unit 7 calculates a pullback speed V1 ′ and a cueing speed V2 ′ that satisfy the relational expression of (T2′−T1 ′) ≦ 0, and sends the pullback speed V1 ′ to the printing paper transport control unit 7a. Further, the cueing speed V2 ′ is set in the ink sheet conveyance control unit 7b (step S6 ″). Other steps are the same as those in FIG.

  As described above, the control unit 7 of the thermal transfer printer 100 according to the third embodiment of the present invention has a predetermined time difference (T2−T1) obtained by subtracting the pullback time T1 from the cue time T2. Both the cue time T2 and the pull-back time T1 are controlled so as to be within the specified value. When the time difference (T2−T1) is larger than the specified value, the control unit 7 decreases the conveyance speed of the printing paper 2a when the printing paper 2a is conveyed from the first printing end position 22 to the second printing start position 21. Thus, the pull-back time T1 is extended, and the ink sheet 1 is transported at a speed when the ink sheet 1 is transported from the ink use end position 12a in the first ink area 10a to the ink use start position 11b in the second ink area 10b. The cue time T2 is shortened by increasing. With the configuration described above, the cueing operation of the ink sheet 1 performed by the thermal transfer printer 100 is completed at the same time as or before the completion of the pulling-back operation of the printing paper 2a. Therefore, the thermal transfer printer 100 can prevent soiling. Further, the boundary detection sensor provided in the thermal transfer printer 100 can keep the boundary determination error of each ink region 10 within an allowable range. As a result, the thermal transfer printer 100 can improve the printing accuracy while suppressing an increase in the cost of the ink sheet 1.

  Further, in the control method of the thermal transfer printer 100 according to the third embodiment of the present invention, at least before the second printing step, the control unit 7 subtracts the pull-back time T1 from the cue time T2 ( There is further provided a timing control step for controlling both the cue time T2 and the pull back time T1 so that T2-T1) is within a predetermined value. The timing control step is performed when the control unit 7 conveys the printing paper 2a from the first print end position 22 to the second print start position 21 when the time difference (T2-T1) is larger than a specified value. The conveyance speed of the ink sheet 1 when the conveyance speed of the printing paper 2a is decreased and the ink sheet 1 is conveyed from the ink use end position 12a in the first ink area 10a to the ink use start position 11b in the second ink area 10b. Increase. With the above configuration, the cueing operation of the ink sheet 1 included in the control method of the thermal transfer printer 100 is completed at the same time as or before the completion of the pulling-back operation of the printing paper 2a. Therefore, the control method of the thermal transfer printer 100 according to the third embodiment can prevent background contamination. Further, the boundary determination error of the boundary detection sensor provided in the thermal transfer printer 100 can be within an allowable range. As a result, the thermal transfer printer 100 can improve the printing accuracy while suppressing an increase in the cost of the ink sheet 1.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  DESCRIPTION OF SYMBOLS 1 Ink sheet, 2a Printing paper, 7 Control part, 7a Printing paper conveyance control part, 7b Ink sheet conveyance control part, 10 Ink area, 10a 1st ink area, 10b 2nd ink area, 11a Ink use start position, 11b Ink Use start position, 12a Ink use end position, 20 print area, 21 print start position, 22 print end position, 100 thermal transfer printer, D1 pull back distance, D2 cue distance, T1 pull back time, T2 cue time, V1 pull back speed, V2 Cue speed, t Specified value.

Claims (6)

A thermal transfer printer that prints a color image by transferring an image of each color to a printing area on a printing paper,
Control means for controlling the conveyance of an ink sheet in which a plurality of colors of ink are arranged for each color in a plurality of ink regions partitioned in the conveyance direction and the conveyance of the printing paper;
The plurality of ink regions include a first ink region containing the ink used for the first printing on the printing region and the ink used for the second printing on the printing region performed after the first printing. A second ink region,
The control means conveys the ink sheet from an ink use end position in the first ink area used for the first print to an ink use start position in the second ink area used for the second print. The time difference obtained by subtracting the pull-back time required to transport the printing paper from the first print end position in the print area to the second print start position in the print area The thermal transfer printer, wherein the cue time or the pull back time is controlled so as to be within a predetermined value.   The said control means reduces the conveyance speed of the said printing paper at the time of conveying the said printing paper from the said 1st printing completion position to the said 2nd printing start position, when the said time difference is larger than the said regulation value. The thermal transfer printer according to 1.   When the time difference is larger than the specified value, the control means transports the ink sheet from the ink use end position in the first ink area to the ink use start position in the second ink area. The thermal transfer printer according to claim 1, wherein a conveyance speed of the ink sheet is increased. Control of a thermal transfer printer that prints a color image by transferring an image of each color to a print area on a printing paper using an ink sheet in which a plurality of colors of ink are arranged for each color in a plurality of ink areas divided in the transport direction A method,
A first printing step in which the control means performs a first print on the print area using the ink of the first ink area included in the plurality of ink areas;
The control means includes a second printing step of performing a second printing on the printing area using the ink of the second ink area included in the plurality of ink areas after the first printing step;
In the thermal transfer printer control method, at least before the second printing step, the control means is used for the second printing from the ink use end position in the first ink area used for the first printing. From the cue time required to transport the ink sheet to the ink use start position in the second ink area, the first print end position in the print area to the second print start position in the print area. A timing control step of controlling the cue time or the pull back time so that a time difference obtained by subtracting the pull back time required for transporting the printing paper is within a predetermined value set in advance; A control method for a thermal transfer printer. The timing control step includes:
When the time difference is larger than the specified value, the control means reduces the conveyance speed of the printing paper when conveying the printing paper from the first printing end position to the second printing start position. A method for controlling a thermal transfer printer according to claim 4. The timing control step includes:
When the control means conveys the ink sheet from the ink use end position in the first ink area to the ink use start position in the second ink area when the time difference is larger than the specified value. The method for controlling a thermal transfer printer according to claim 4, further comprising increasing a conveyance speed of the ink sheet.

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