JP2014008686A - Image forming device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which enables rerecording onto a recorded medium having data recorded thereon with high-speed and a simple structure, and a control method thereof.SOLUTION: An image forming device 1 has a recording head 111, an ink film cartridge 112, a recording control part 12, a head drive part 13, and a recording paper conveyance part 14. The ink film cartridge 112 has a printing ink film and an erasing ink film having a similar color to a printing surface of a recorded medium. The erasing ink film is arranged in the upstream side in a sub-scanning direction relative to the printing ink film.

Description

  The present invention relates to an image forming apparatus and a control method thereof.

  In recent years, due to increasing interest in effective use of resources, there has been a movement to save recording paper by double-sided printing, Nin1 printing that prints a plurality of pages on one sheet, backing paper printing, and the like. However, the recording paper once printed on both sides cannot be used again. In Nin1 printing, a plurality of pages are reduced to fit on one sheet, so that the character size is smaller than the original character. In the case of backing paper printing, there is a risk that the side that was originally printed will be mistaken for the side that was printed by reuse.

  Patent Document 1 discloses a printer device that includes an erasing roller and a drying roller. The printer device described in Patent Document 1 applies an erasing liquid onto a printed surface using an erasing roller. Then, the printer device dries the liquid using a drying roller. Thereafter, the printer device prints again on the side from which the record is erased.

  Patent Document 2 discloses a thermal transfer printer in which a printing thermal head and an erasing thermal head are arranged along a platen. In the thermal transfer printer of Patent Document 2, the printing thermal head performs reprinting on the portion where the recording is erased by the erasing thermal head.

JP-A-6-286269 JP-A-1-44768

  However, the printer device described in Patent Document 1 requires a special liquid agent for erasing. In addition, electrical and mechanical parts for erasing are required. Therefore, there is a problem that the configuration is complicated as compared with a normal printer.

  In the thermal transfer printer described in Patent Document 2, the thermal head for printing and the thermal head for erasing are arranged side by side along the platen, that is, along the main scanning direction. Therefore, in order for the printing thermal head to perform reprinting on the portion where the recording has been erased by the erasing thermal head, it is necessary that the erasing thermal head be at the head and the carriage move in the main scanning direction. For this reason, during printing, there is a problem in that the moving direction of the carriage in the main scanning direction is limited and printing takes time.

  The present invention has been made to solve such a problem, and provides an image forming apparatus capable of re-recording on a recorded medium with a high-speed and simple configuration, and a control method therefor. It is aimed.

  An image forming apparatus according to an aspect of the present invention includes a medium conveying unit that conveys a recording medium in a sub-scanning direction, an ink cartridge having a printing ink and an erasing ink having a color similar to the printing surface of the recording medium. A recording head that is movable in the main scanning direction of the recording medium and that prints on the recording medium using ink of the ink cartridge; and a head driving unit that drives the recording head in the main scanning direction. The erasing ink is disposed upstream of the printing ink in the sub-scanning direction.

  An image forming apparatus control method according to an aspect of the present invention includes: an ink cartridge having a printing ink and an erasing ink having a color similar to a printing surface of a recording medium; and the ink in the ink cartridge. And a recording head for printing on a recording medium, wherein the recording medium is conveyed in a sub-scanning direction, the recording head is moved in a main scanning direction of the recording medium, and the printing is performed. The erasing ink is printed on the recording medium on the upstream side in the sub-scanning direction from the position where the printing ink is printed on the recording medium.

  According to the present invention, it is possible to provide an image forming apparatus capable of re-recording on a recording medium that has been recorded with a high-speed and simple configuration, and a control method therefor.

1 is a block diagram of an image forming apparatus according to a first embodiment. FIG. 6 is a diagram for explaining the operation of the head unit according to the first embodiment; FIG. 4 is a diagram for explaining the operation of the image forming apparatus according to the first embodiment. FIG. 4 is a diagram for explaining the operation of the image forming apparatus according to the first embodiment. FIG. 3 is a block diagram of an image forming apparatus according to a second embodiment. FIG. 10 is a diagram for explaining an operation of the image forming apparatus according to the second embodiment. FIG. 10 is a diagram for explaining an operation of the image forming apparatus according to the second embodiment.

<Embodiment 1>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 is a thermal transfer recording apparatus that can print input print data on a recording sheet using a thermal transfer method. The print data is data transmitted from a PC (Personal Computer), a scanner, or the like, and is data indicating the shape, color, etc. of the image to be printed on the recording paper.

<Configuration of Image Forming Apparatus 1>
The image forming apparatus 1 includes a head unit 11, a recording control unit 12, a head driving unit 13, and a recording paper transport unit 14.

  The head unit 11 is a part that scans the recording surface of the recording paper and prints an image (character). The scanning operation of the head unit 11 will be described with reference to FIG. The head unit 11 is supported by the shaft unit 15 and disposed on the recording surface of the recording paper 90. The head part 11 is movable in the axial direction of the shaft part 15. In the following description, the direction in which the recording paper 90 is conveyed (vertical direction in FIG. 2) is the sub-scanning direction, and the direction substantially perpendicular to the sub-scanning direction (the direction in which the head unit 11 is movable, that is, FIG. 2). Is the main scanning direction.

  The head unit 11 includes a recording head 111 and an ink film cartridge 112. The recording head 111 has a plurality of heating elements formed in a matrix. Specifically, the recording head 111 has a heating element composed of a matrix of n in the main scanning direction and (m × 5) in the sub scanning direction. For example, when the resolution is 600 dpi, the pitch of the heating elements is about 0.042 mm.

  The ink film cartridge 112 stores a tape-shaped ink film. In the present embodiment, ink films of five colors of white, cyan, magenta, yellow, and black are arranged in a strip shape on the ink film. More specifically, a white band, a cyan band, a magenta band, a yellow band, and a black band are arranged from the upstream side in the sub-scanning direction. The upstream side in the sub-scanning direction is the side on which the recording paper is supplied, and means the side opposite to the recording paper discharge side (the lower side in FIG. 2). The width of each color band corresponds to the length of m heating elements arranged in the sub-scanning direction of the recording head 111.

  The recording control unit 12 includes a CPU (Central Processing Unit), and outputs a control signal to each block shown in FIG. 1 based on a control program stored in a memory (not shown) to perform a printing operation of the image forming apparatus 1. Control.

  Specifically, the recording control unit 12 supplies power to the heating element of the recording head 111 based on the input print data. As a result, the recording control unit 12 causes the heating element to perform thermal transfer. The recording control unit 12 uses the head driving unit 13 to reciprocate the head unit 11 in the sub-scanning direction. Further, the recording control unit 12 causes the recording paper conveyance unit 14 to execute conveyance of the recording paper.

  The head drive unit 13 moves the head unit 11 in the sub-scanning direction using a motor (not shown) according to a command from the recording control unit 12. The head driving unit 13 winds up the ink film having the same length as the movement amount from the ink film cartridge 112 in accordance with the movement of the head unit 11.

  The recording paper transport unit 14 moves the recording paper in the sub-scanning direction using a motor (not shown) according to a command from the recording control unit 12. Specifically, the recording paper transport unit 14 sub-scans the recording paper by a distance corresponding to m heating elements of the recording head 111 each time the head unit 11 moves from one end to the other end of the recording paper in the main scanning direction. Move in the direction. That is, the recording paper transport unit 14 moves the recording paper by the width of the band of the ink film every time the head unit 11 moves from one end to the other end of the recording paper in the main scanning direction.

<Operation Example of Image Forming Apparatus 1>
Subsequently, an operation example of the image forming apparatus 1 according to the present embodiment will be described with reference to FIGS. 3 and 4. 3 and 4 are diagrams showing changes in the image recorded on the recording paper 90, in which changes in the image on the recording paper 90 from time t1 to time t10 are arranged in time series.

  3 and 4 are views of the recording paper 90, the heating element, and the ink film cartridge 112 as viewed from the side, and show the positional relationship in the sub-scanning direction. As described above, the lines of each color of the ink film are arranged adjacent to white, cyan, magenta, yellow, and black from the upstream side in the sub-scanning direction (lower side in FIGS. 3 and 4). Further, heating elements 111a to 111e are arranged corresponding to the ink films of the respective colors.

  That is, the white (erased color) ink film is disposed on the upstream side in the sub-scanning direction with respect to the ink films of other colors (cyan, magenta, yellow, black, hereinafter also referred to as print color). Therefore, the recording head 111 prints white ink on the recording paper 90 on the upstream side in the sub-scanning direction from the printing position of the printing color ink.

  The white ink film and the printing color ink film are formed on the same ink film. Further, the white heating element 111 a and the other color heating elements 111 b to 111 e are formed on the same recording head 111. With such a configuration, a separate member for erasing is not required, so that the configuration of the image forming apparatus 1 can be simplified.

  At time t1, as an initial state, it is assumed that black, round, cross, triangle and square figures have already been printed on the recording paper 90 from the left. The image forming apparatus 1 erases these figures and reprints them. The recording head 111 thermally transfers white and print colors for each line (lines L1 to L5) that is substantially the same width as the width of the white ink film in the sub-scanning direction and extends in the main scanning direction based on the print data. To do.

  At time t2, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, white ink is printed on the line L1 of the recording paper 90. As a result, the image previously printed on the line L1 is deleted.

  At time t3, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L2. A cyan ink film is disposed on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, the white ink is printed on the line L2 of the recording paper 90. As a result, the image previously printed on the line L2 is deleted.

  Further, it is assumed that the input print data includes data to be printed in cyan on the line L1 of the recording paper 90. Therefore, the head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111b corresponding to the cyan ink film at a timing according to the print data. As a result, cyan is printed on the line L1 from which the image is erased at time t2. That is, while the head unit 11 moves from one end of the recording paper 90 to the other end, white ink is printed on the line L2 of the recording paper 90 and cyan is printed at a position corresponding to the print data of the line L1. The

  At time t4, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L3. A cyan ink film is disposed on the line L2. A magenta ink film is disposed on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, the white ink is printed on the line L3 of the recording paper 90. As a result, the image previously printed on the line L3 is deleted.

  Further, it is assumed that the input print data includes data to be printed in magenta color on the line L1 of the recording paper 90. It is assumed that there is data to be printed in cyan on the line L2. Therefore, the head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111b corresponding to the cyan ink film and the heating element 111c corresponding to the magenta ink film at a timing according to the print data. As a result, the magenta color is printed on the line L1 from which the image is erased at time t2. Further, cyan is printed on the line L2 from which the image is erased at time t3. Note that white, cyan, and magenta are simultaneously printed while the head unit 11 moves from one end of the recording paper 90 to the other end, as at time t3. That is, between the times t3 and t4, the head unit 11 reciprocates both ends of the recording paper 90 in the main scanning direction.

  At time t5, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L4. A cyan ink film is disposed on the line L3. A magenta ink film is disposed on the line L2. A yellow ink film is disposed on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, the white ink is printed on the line L4 of the recording paper 90. As a result, the image previously printed on the line L4 is deleted.

  Further, it is assumed that the input print data includes data to be printed in yellow on the line L1 of the recording paper 90. It is assumed that there is data to be printed in magenta color on the line L2. Assume that there is data to be printed in cyan on the line L3. Therefore, the head drive unit 13 moves the head unit 11 in the main scanning direction. The recording control unit 12 supplies power to the heating element 111b corresponding to the cyan ink film, the heating element 111c corresponding to the magenta ink film, and the heating element 111d corresponding to the yellow ink film at a timing according to the print data. To do. As a result, the yellow color is printed on the line L1 from which the image is erased at time t2. The magenta color is printed on the line L2 from which the image is erased at time t3. The cyan color is printed on the line L3 from which the image is erased at time t4.

  At time t6, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L5. A cyan ink film is disposed on the line L4. A magenta ink film is disposed on the line L3. A yellow ink film is disposed on the line L2. A black ink film is disposed on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, the white ink is printed on the line L5 of the recording paper 90. As a result, the image previously printed on the line L5 is deleted. That is, all the images that have been printed in advance at time t1 are deleted.

  Further, it is assumed that the input print data includes data to be printed in black on the line L1 of the recording paper 90. Assume that there is data to be printed in yellow on the line L2. It is assumed that there is data to be printed in magenta color on the line L3. It is assumed that there is data to be printed in cyan on the line L4. Therefore, the head drive unit 13 moves the head unit 11 in the main scanning direction. The recording control unit 12 prints on the heating element 111b corresponding to the cyan ink film, the heating element 111c corresponding to the magenta ink film, the heating element 111d corresponding to the yellow ink film, and the heating element 111e corresponding to the black ink film. Power is supplied at a timing according to the data. As a result, black is printed on the line L1 from which the image is erased at time t2. A yellow color is printed on the line L2 from which the image is erased at time t3. The magenta color is printed on the line L3 from which the image is erased at time t4. A cyan color is printed on the line L4 from which the image is erased at time t5.

  At time t7, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction. Thereby, the cyan ink film is arranged on the line L5. A magenta ink film is disposed on the line L4. A yellow ink film is disposed on the line L3. A black ink film is disposed on the line L2.

  Then, the recording control unit 12 prints on the heating element 111b corresponding to the cyan ink film, the heating element 111c corresponding to the magenta ink film, the heating element 111d corresponding to the yellow ink film, and the heating element 111e corresponding to the black ink film. Power is supplied at a timing according to the data. As a result, black is printed on the line L2 from which the image is erased at time t3. A yellow color is printed on the line L3 from which the image is erased at time t4. The magenta color is printed on the line L4 from which the image is erased at time t5. A cyan color is printed on the line L5 from which the image is erased at time t6.

  Similarly, from time t7 to t10, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction at each time. Then, while the head driving unit 13 moves the head unit 11 in the main scanning direction, the recording control unit 12 supplies power to the heating elements 111b to 111e based on the print data. Thereby, each print color is printed at a position corresponding to the print data.

  As described above, according to the configuration of the image forming apparatus 1 according to the present embodiment, the recording paper transport unit 14 transports the recording paper 90 in the sub-scanning direction. The ink film cartridge 112 includes a printing ink film and an erasing ink film. The erasing ink film is disposed on the upstream side in the sub-scanning direction with respect to the printing ink film. Therefore, the image forming apparatus 1 can convey the recording paper 90 while erasing the image using the erasing ink film on the upstream side of the printing ink film even if the image is printed on the recording paper 90 in advance. Accordingly, the recording paper 90 printed by the printing ink film is in a state where the image is erased. As a result, it is possible to print again on the recording surface of the printed recording paper 90.

  Further, the image forming apparatus 1 can erase printed image data only by adding a white ink film and a corresponding heating element 111a in addition to a normal printing color. Therefore, no special liquid agent or configuration is required. Therefore, the reuse of the printed recording paper 90 can be realized at low cost. In addition, size reduction of the image forming apparatus 1 can be realized.

  Further, in the image forming apparatus 1, the white ink film is disposed on the upstream side in the sub-scanning direction with respect to the print color ink film. Therefore, the printed image data for two lines can be erased while the head unit 11 reciprocates once in the main scanning direction. For example, when the white ink film is arranged in the main scanning direction with respect to the printing color ink film, the printed image data can be erased only when the white ink film moves at the head in the main scanning direction. is there. For this reason, the printed image data can be erased only for one line while the head unit 11 reciprocates once in the main scanning direction. That is, according to the configuration of the image forming apparatus 1 according to the present embodiment, the erasing operation can be performed efficiently, and the printing time can be shortened.

<Embodiment 2>
A second embodiment according to the present invention will be described. FIG. 5 is a block diagram of the image forming apparatus 2 according to the present embodiment.

<Configuration of Image Forming Apparatus 2>
The image forming apparatus 2 includes a reading element 21 in addition to the configuration of the image forming apparatus 1 shown in FIG. Since the other configuration is the same as that of the image forming apparatus 1, description thereof will be omitted as appropriate.

  The reading element 21 is provided adjacent to the heating element of the recording head 111. More specifically, the reading element 21 is provided on the upstream side in the sub-scanning direction with respect to the heating element. The reading element 21 detects whether an image is printed on the recording paper. That is, the reading element 21 is a sensor that detects the presence or absence of an image printed on recording paper. A known technique can be used to detect an image using the reading element 21. For example, the reading element 21 detects whether or not an image is printed on the recording paper based on the light reflectance, color information, and the like of the recording paper.

  The head drive unit 13 controls the movement of the head unit 11 in the main scanning direction based on the detection result of the reading element 21. Specifically, the recording control unit 12 outputs a control signal for moving the head unit 11 in the main scanning direction to the head driving unit 13 based on the detection result of the reading element 21. The head drive unit 13 moves the head unit 11 in the main scanning direction in accordance with a control signal from the recording control unit 12.

  The recording paper transport unit 14 changes the transport amount of the recording paper based on the detection result of the reading element 21. Specifically, the recording control unit 12 outputs a control signal for changing the conveyance amount of the recording paper to the recording paper conveyance unit 14 based on the detection result of the reading element 21. The recording paper transport unit 14 changes the transport amount of the recording paper according to the control signal from the recording control unit 12.

<Operation Example of Image Forming Apparatus 2>
Subsequently, an operation example of the image forming apparatus 2 according to the present embodiment will be described with reference to FIGS. 6 and 7. 6 and 7 correspond to FIGS. 3 and 4 in the first embodiment. The color order of the ink films is the same as the order shown in FIGS. However, it differs from FIGS. 3 and 4 in that the reading element 21 is provided adjacent to the upstream side of the heating element 111a in the sub-scanning direction.

  At time t11, as an initial state, it is assumed that a plurality of black lines extending in the main scanning direction are printed in advance on the recording paper 90. The image forming apparatus 2 erases these prints and reprints them.

  At this time, the reading element 21 detects whether an image is printed on the first and second lines ahead of the line on which the white ink film is arranged. In FIG. 6, at time t11, the reading element 21 detects whether or not images are printed on the lines L1 and L2.

  In FIG. 6, an image is printed on a line L1 that is one line ahead of the line on which the white ink film is arranged. The reading element 21 outputs a detection result indicating that an image is printed one line ahead to the recording control unit 12. In addition, the reading element 21 outputs a detection result indicating that an image is not printed two lines ahead to the recording control unit 12.

  Since the image is printed on the line L1 that is one line ahead of the line where the white ink film is arranged, it is necessary to erase the image printed on the line L1 with the white ink. Therefore, the recording control unit 12 instructs the recording paper transport unit 14 to transport the recording paper 90 by the line width of the white ink film.

  At time t12, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction in accordance with an instruction from the recording control unit 12. Thereby, a white ink film is arrange | positioned on the line L1.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, white ink is printed on the line L1 of the recording paper 90. As a result, the image previously printed on the line L1 is deleted.

  Further, the reading element 21 detects whether or not an image is printed on one line ahead (line L2) and two lines ahead (line L3) while the head unit 11 moves in the main scanning direction. Then, the reading element 21 outputs to the recording control unit 12 that an image is not printed at one line ahead and an image is printed at two line ahead.

  The recording control unit 12 recognizes that no image is printed one line ahead based on the detection result of the reading element 21. That is, the recording control unit 12 recognizes that it is not necessary to print white ink at one line ahead.

  In the print data in this example, it is assumed that the line L1 does not include data to be printed in cyan. Therefore, the recording control unit 12 recognizes that there is no data to be printed in cyan on the line (line L1) where white is currently printed based on the print data. Therefore, even if the recording paper 90 is transported by one line in the sub-scanning direction by the recording paper transporting unit 14, it is not necessary to move the head unit 11 in the main scanning direction.

  Therefore, the recording control unit 12 outputs an instruction to the head driving unit 13 that the head unit 11 is not moved in the main scanning direction in a state where the white ink film is arranged on the line L2. In addition, the recording control unit 12 outputs an instruction to the recording paper conveyance unit 14 to convey the recording paper 90 in the sub-scanning direction by two lines, that is, twice the line width of the white ink film. .

  At time t13, the recording paper transport unit 14 transports the recording paper 90 in the sub-scanning direction by twice the line width of the white ink. Thereby, a white ink film is arrange | positioned on the line L3. A cyan ink film is disposed on the line L2. A magenta ink film is disposed on the line L1. That is, as shown by tx in FIG. 6, the state in which the recording paper 90 has advanced by one line from time t12 is skipped.

  The head drive unit 13 moves the head unit 11 in the main scanning direction. Then, the recording control unit 12 supplies power to the heating element 111a corresponding to the white ink film. As a result, the white ink is printed on the line L3 of the recording paper 90. As a result, the image previously printed on the line L3 is deleted.

  Further, it is assumed that the input print data includes data to be printed in magenta color on the line L1 of the recording paper 90. It is assumed that there is data to be printed in cyan on the line L2. Therefore, the recording control unit 12 supplies power to the heating element 111b corresponding to the cyan ink film and the heating element 111c corresponding to the magenta ink film at a timing according to the print data. As a result, the magenta color is printed on the line L1 from which the image is erased at time t12. A cyan color is printed on the line L2.

  The reading element 21 detects whether an image is printed on one line ahead (line L4) and two lines ahead (line L5). Then, the reading element 21 outputs to the recording control unit 12 that an image is not printed at one line ahead and an image is printed at two line ahead.

  The recording control unit 12 recognizes that no image is printed one line ahead based on the detection result of the reading element 21. That is, the recording control unit 12 recognizes that it is not necessary to print white ink at one line ahead.

  However, in the print data in this example, it is assumed that the line L3 includes data to be printed in cyan. Therefore, the recording control unit 12 recognizes that there is data to be printed in cyan on the line (line L3) where white is currently printed based on the print data. Therefore, after the recording paper 90 is conveyed by one line in the sub-scanning direction, it is necessary to move the head unit 11 in the main scanning direction in order to print cyan.

  Therefore, the recording control unit 12 outputs an instruction to the head driving unit 13 to move the head unit 11 in the main scanning direction with the cyan ink film disposed on the line L3. The recording control unit 12 outputs an instruction to the recording paper conveyance unit 14 to convey the recording paper 90 in the sub-scanning direction by one line, that is, the line width of the white ink film.

  At time t14, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink in the sub-scanning direction. Thereby, a white ink film is arrange | positioned on the line L4. A cyan ink film is disposed on the line L3. A magenta ink film is disposed on the line L2. A yellow ink film is disposed on the line L1.

  It is assumed that the input print data includes data to be printed in yellow on the line L1 of the recording paper 90. Assume that there is data to be printed in magenta color on the line L2. Assume that there is data to be printed in cyan on the line L3. Therefore, the head drive unit 13 moves the head unit 11 in the main scanning direction. The recording control unit 12 supplies power to the heating element 111b corresponding to the cyan ink film, the heating element 111c corresponding to the magenta ink film, and the heating element 111d corresponding to the yellow ink film at a timing according to the print data. To do. Thereby, the yellow color is printed on the line L1 from which the image is erased at time t12. A magenta color is printed on the line L2. A cyan color is printed on the line L3 from which the image is erased at time t13.

  At time t14, as detected by the reading element 21, image data to be erased is not printed. Therefore, the recording control unit 12 does not supply power to the heating element 111a corresponding to the white ink film based on the detection result of the reading element 21. Thereby, while the head unit 11 moves in the main scanning direction, the printing colors (cyan, magenta, yellow) are printed, but white printing is not performed.

  Similarly, at time t15, t16, and t18, the recording paper transport unit 14 transports the recording paper 90 by the line width of the white ink film in the sub-scanning direction at each time. Then, while the head driving unit 13 moves the head unit 11 in the main scanning direction, the recording control unit 12 supplies power to the heating elements 111b to 111e based on the print data. Thereby, each print color is printed at a position corresponding to the print data.

  However, at time t17, similarly to time t13, even if the recording paper 90 is conveyed by one line in the sub-scanning direction, it is not necessary to print the printing color and white ink. Therefore, the recording control unit 12 outputs an instruction to the head driving unit 13 that the head unit 11 is not moved in the main scanning direction. Further, the recording control unit 12 sets the recording paper 90 by two lines, that is, twice the line width of the white ink film with respect to the recording paper transport unit 14 based on the detection result of the reading element 21 and the print data. Is instructed to be conveyed in the sub-scanning direction. That is, as shown by ty in FIG. 7, the state where the recording paper 90 has advanced by one line from time t16 is skipped.

  As described above, according to the configuration of the image forming apparatus 2 according to the present embodiment, the reading element 21 detects the presence or absence of image data one line ahead of the line on which the white ink film is arranged. The head driving unit 13 controls the movement of the recording head 111 in the main scanning direction based on the detection result of the reading element 21 and the input print data. That is, the head driving unit 13 does not move the recording head 111 in the main scanning direction when there is no image data to be erased and there is no data to be printed. Therefore, a wasteful operation of the recording head 111 can be omitted compared to a printing operation in which an erasing operation is performed regardless of the presence or absence of image data to be erased. As a result, the printing time can be shortened.

  In addition, the recording paper transport unit 14 controls the transport amount of the recording paper 90 in the sub-scanning direction based on the detection result of the reading element 21 and the input print data. That is, the recording paper transport unit 14 transports the recording paper 90 two lines at a time in accordance with an instruction from the recording control unit 12 when there is no image data to be erased and no data to be printed. Let As a result, the printing time can be further shortened.

  Further, the reading element 21 detects not only one line ahead of the line on which the white ink film is arranged but also the presence / absence of image data of two lines ahead. Thereby, the printing time can be further shortened.

  Specifically, considering a configuration in which the reading element 21 detects only image data one line ahead, if there is no image data to be erased one line ahead, that one line can be skipped. However, since the presence / absence of image data is not detected in the line where the white ink film is arranged after being skipped, it is necessary to perform an erasing operation regardless of the presence / absence of image data.

  On the other hand, when the reading element 21 detects the presence or absence of the image data of two lines ahead (second line), the recording control unit 12 skips one line (line 2 where the white ink film is arranged). The presence / absence of image data on the (line) can also be recognized. Therefore, when there is no image to be erased two lines ahead (second line), the head driving unit 13 skips one line (that is, when the white ink film is arranged on the second line). The head unit 11 is not moved in the main scanning direction. Thereby, the printing time can be further shortened. Of course, the reading element 21 may detect the presence or absence of an image up to two or more lines ahead of the line where the white ink film is arranged.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed and combined without departing from the spirit of the present invention. For example, in the above description, the case where the image forming apparatuses 1 and 2 perform printing using the thermal transfer method is described, but the present invention is not limited to this, and the present invention can also be applied to an inkjet printing method. However, since sufficient ink quick drying is required, the image forming apparatus is preferably a thermal transfer system.

  In the embodiment described above, paper is used as a recording medium, but the present invention is not limited to this. The recording medium may be a film or sheet containing components other than paper as long as it is a printable medium.

  Furthermore, in the above-described embodiment, white is used as the erasing color, but the present invention is not limited to this. The erasure color may be a color similar to that of the recording paper (recording medium), and may be a color other than white.

DESCRIPTION OF SYMBOLS 1, 2 Image forming apparatus 11 Head part 12 Recording control part 13 Head drive part 14 Recording paper conveyance part 15 Shaft part 21 Reading element 90 Recording paper 111 Recording head 112 Ink film cartridge

Claims (10)

Medium conveying means for conveying the recording medium in the sub-scanning direction;
An ink cartridge having a printing ink and an erasing ink of the same color as the printing surface of the recording medium;
A recording head that is movable in a main scanning direction of the recording medium and that prints on the recording medium using ink of the ink cartridge;
Head driving means for driving the recording head in the main scanning direction,
The image forming apparatus, wherein the erasing ink is disposed upstream of the printing ink in a sub-scanning direction. A reading unit provided on the upstream side of the recording head and detecting the presence or absence of an image printed on the recording medium;
The image forming apparatus according to claim 1, wherein the head driving unit controls movement of the recording head in a main scanning direction based on a detection result of the reading unit.   The image forming apparatus according to claim 2, wherein the medium conveyance unit changes a conveyance amount of the recording medium based on a detection result of the reading unit. The ink cartridge has a printing ink film and an erasing ink film disposed on the upstream side thereof,
The medium conveying means conveys the recording medium in the sub-scanning direction by the width in the sub-scanning direction of the erasing ink film,
The recording head includes a heating element that thermally transfers the printing ink and the erasing ink to the recording medium, and the printing ink is provided for each line having a width substantially the same as the width in the sub-scanning direction of the erasing ink film. And thermally transferring the erasing ink to the recording medium,
The reading means detects the presence or absence of an image recorded on a first line located adjacent to a line on which the erasing ink is printed and located on the upstream side;
The head driving means does not move the recording head in the main scanning direction when the erasing ink film is positioned on the first line when no image is recorded on the first line. The image forming apparatus according to 3. The reading means further detects the presence or absence of an image printed on a second line adjacent to the upstream side of the first line;
5. The head driving unit according to claim 4, wherein when the image is not recorded on the second line, the head driving unit does not move the recording head in the main scanning direction in a state where the erasing ink film is positioned on the second line. The image forming apparatus described.   The said medium conveyance means conveys the said to-be-recorded medium for the distance of double the width | variety of the subscanning direction of the said erasing ink film, when the image is not printed on the said 1st line. Image forming apparatus.   The image forming apparatus according to claim 4, wherein the printing ink film and the erasing ink film are provided on the same ink film.   The image forming apparatus according to claim 4, wherein the heating element for printing and the heating element for erasure are formed integrally.   The image forming apparatus according to claim 1, wherein the erasing ink is white. An image forming apparatus comprising: an ink cartridge having a printing ink and an erasing ink of the same color as the printing surface of the recording medium; and a recording head for printing on the recording medium using the ink of the ink cartridge. A control method,
Transport the recording medium in the sub-scanning direction;
Moving the recording head in the main scanning direction of the recording medium;
A control method for an image forming apparatus, wherein the erasing ink is printed on the recording medium upstream of a position where the printing ink is printed on the recording medium in a sub-scanning direction.

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