JP2017213795A - Curl correction apparatus and thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curl correction apparatus which can efficiently and appropriately correct curl of a photographic paper occurring upon printing.SOLUTION: There is provided the curl correction apparatus for correcting curl of a photographic paper in which printing is performed by heating the photographic paper from the printing surface side of the photographic paper using a thermal head. The curl correction apparatus comprises: a conveyance path which conveys the photographic paper; characteristic distribution measurement means which is provided on the printing surface side or the rear side of the printing surface of the photographic paper conveyed in the conveyance path and measures the characteristic distribution of the photographic paper; heating means which is provided on the rear side of the photographic paper conveyed in the conveyance path and applies heat to the photographic paper from the rear side; and heating control means which controls heat on the basis of the characteristic distribution.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a curl correction apparatus and a thermal printer, and more particularly to a technique for correcting curling of photographic paper.

  A thermal printer that can correct curling of photographic paper has a curling head in addition to the thermal head for printing. The curling head heats the photographic paper from the opposite side of the printing screen, that is, from the back. to correct. The curl correction device provided in the thermal printer described in Patent Document 1 is a device that heats and uniformly corrects photographic paper. For a photographic paper having a certain curl like a rolled photographic paper. Can be an appropriate means of correction.

JP 2000-318194 A

  However, the curl correction apparatus described in Patent Document 1 is not an appropriate correction means for photographic paper whose curl amount is not constant. In actual printing by a thermal printer, curling occurs due to printing heat corresponding to the printing density, so the curl amount after printing is not uniform within the printing paper surface. If the curl correction device heats photographic paper with a non-uniform curl amount in the surface uniformly, the curl amount may be insufficient due to insufficient correction amount depending on the location, or conversely, the correction amount is excessive and heated. There was a problem that the curl was stronger than before.

  In addition, the curl correction device that uniformly heats as described above may add excessive heat to the photographic paper that exceeds the amount of heat necessary for correction, and there is a problem that the power consumption of the thermal printer increases.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a curl correction apparatus that can efficiently and appropriately correct curling of photographic paper that occurs during printing.

  The curl correction apparatus according to the present invention is a curl correction apparatus that corrects curling of photographic paper printed by a thermal head heated from the printing screen side of the photographic paper, a conveyance path for conveying the photographic paper, Provided on the printing screen side or back side of the photographic paper transported in the transport path, provided on the back side of the photographic paper transported in the transport path, characteristic distribution measuring means for measuring the characteristic distribution of the photographic paper, A heating unit that applies heat to the photographic paper from the back side and a heating control unit that controls the amount of heat based on the characteristic distribution are provided.

  According to the curl correcting apparatus according to the present invention, it is possible to provide a curl correcting apparatus that can efficiently and appropriately correct curling of photographic paper generated during printing. Moreover, according to the thermal printer provided with the curl correction apparatus according to the present invention, it is possible to perform correction according to the curl amount generated at the time of printing, and it is possible to obtain a thermal printer capable of printing with good finished quality.

1 is a cross-sectional view illustrating a configuration of a thermal printer in a first embodiment. 1 is a block diagram illustrating a configuration of a thermal printer in Embodiment 1. FIG. 1 is a perspective view showing a configuration of a thermal printer in Embodiment 1. FIG. 3 is a flowchart illustrating a curl correction operation in the first embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a thermal printer in a second embodiment. FIG. 5 is a block diagram illustrating a configuration of a thermal printer in a second embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a thermal printer in a second embodiment. 10 is a flowchart showing a curl correction operation in the second embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a thermal printer in a third embodiment. 10 is a flowchart showing a curl correction operation in the third embodiment. FIG. 10 is a cross-sectional view showing a configuration of a curl correction apparatus in a fourth embodiment. FIG. 10 is a block diagram showing a configuration of a curl correction apparatus in a fourth embodiment. 10 is a flowchart illustrating a curl correction operation in the fourth embodiment.

  Embodiments of a curl correction apparatus and a thermal printer according to the present invention will be described.

<Embodiment 1>
(Configuration of curl correction device and thermal printer)
In the first embodiment, an example in which a thermal printer includes a curl correction device is shown. FIG. 1 is a cross-sectional view showing the configuration of the thermal printer 100 according to the first embodiment. The thermal printer 100 is a printer that prints on a photographic paper 10a fed from a photographic paper roll 10 wound in a roll shape. The thermal printer 100 includes a conveyance path 2 through which the photographic paper 10a is conveyed. Further, the thermal printer 100 is a printing in which a plurality of heating elements are arranged in the width direction of the printing paper 10a (vertical direction in FIG. 1) on the printing screen 1a side of the printing paper 10a conveyed in the conveyance path 2. A thermal head 3 is further provided, and a platen roller 4 is further provided at a position facing the thermal print head 3 with the conveyance path 2 interposed therebetween. During printing, the platen roller 4 presses the printing paper 10a between the printing thermal head 3 and the printing thermal head 3 heats the printing paper 10a from the printing screen 1a to print. The thermal printer 100 includes a pinch roller 5 and a grip roller 6 at positions different from the printing thermal head 3 so as to face each other with the conveyance path 2 therebetween, and driving means (not shown) for driving them. The grip roller 6 and the pinch roller 5 convey the photographic paper 10a drawn from the photographic paper roll 10 while pinching it. The conveying direction of the photographic paper 10a is a direction in which the photographic paper roll 10 and the thermal head 3 for printing are connected. The thermal printer 100 also includes a position sensor 7 that detects the position of the photographic paper 10a in the transport direction, a cutter 8 that cuts the printed photographic paper 10a to a predetermined length, and the cut photographic paper 10a to the outside. And a paper discharge port 9 for paper discharge.

  The curl correction apparatus according to the first embodiment is built in the thermal printer 100, and the conveyance path included in the curl correction apparatus is the conveyance path 2 included in the thermal printer 100. Further, the curl correction apparatus includes a print density sensor 23 on the printing screen 1a side of the printing paper 10a conveyed in the conveyance path 2. The print density sensor 23 is a characteristic distribution measuring device that measures the characteristic distribution of the photographic paper 10a, and is an example of a characteristic distribution measuring unit. In the first embodiment, the print density sensor 23 measures the print density distribution of the photographic paper 10a. In particular, the print density sensor 23 according to the first embodiment is a print density measurement line sensor in which a plurality of print density measurement elements are arranged in a line in the width direction of the photographic paper 10a. Measure the concentration distribution at once. The print density sensor 23 or the print density measuring element includes, for example, an optical sensor, and the optical sensor is, for example, a semiconductor light receiving element. The print density sensor 23 may have a spectral function. Since the print density sensor 23 has a spectral function, the density of the color print can also be measured.

  The curl correction apparatus further includes a correction thermal head 21 that is a heating device for curl correction processing of the photographic paper 10a on the back surface 1b side of the photographic paper 10a conveyed in the conveyance path 2. The correction thermal head 21 is a heating element array in which a plurality of heating elements are arranged in a line in the width direction of the photographic paper 10a. Further, the curl correction apparatus further includes a platen roller 22 at a position facing the correction thermal head 21 across the conveyance path 2. During the curl correction operation, the platen roller 22 presses the printing paper 10a between the correction thermal head 21 and the correction thermal head 21 heats the printing paper 10a from the back surface 1b side of the printing paper 10a. The correction thermal head 21 shown in the first embodiment is an example of a heating unit, and may be another heating device.

  FIG. 2 is a block diagram of the thermal printer control unit 11 provided in the thermal printer 100. The thermal printer control unit 11 includes a printing thermal head control unit 15 connected to the printing thermal head 3 and a position sensor control unit 16 connected to the position sensor 7. The printing thermal head control unit 15 controls the heating of the printing thermal head 3 based on the printing data, and the position sensor control unit 16 controls the operation of the position sensor 7 to control the position measurement of the printing paper 10a. . The thermal printer control unit 11 further includes a drive system control unit 17 connected to the pinch roller 5, the grip roller 6, and the cutter 8, and the drive system control unit 17 controls the operations of the pinch roller 5 and the grip roller 6. Then, the conveyance of the photographic paper 10a is controlled, and the operation of the cutter 8 is controlled to control the cutting of the photographic paper 10a.

  Further, as described above, in the first embodiment, the curl correction apparatus is built in the thermal printer 100. Therefore, the curl correction device control unit 25 included in the curl correction device is built in the thermal printer control unit 11 of the thermal printer 100. The curl correction apparatus control unit 25 includes a correction thermal head control unit 26 connected to the correction thermal head 21 and a print density sensor control unit 27 connected to the print density sensor 23. The correction thermal head control unit 26 is an example of a heating control unit in the curl correction processing operation. Although the detailed control operation of each control unit will be described later, the print density sensor control unit 27 controls the print density sensor 23 to acquire the print density distribution of the print screen 1a, and the correction thermal head control unit 26 acquires the print density distribution. Based on the print density distribution, the amount of correction heat applied to the photographic paper 10a is calculated, and the correction thermal head 21 is heated with the calculated amount of correction heat.

  Further, the thermal printer 100 includes a processing circuit (not shown in detail) for realizing each control operation of each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25. In the first embodiment, the processing circuit includes a CPU 12 and a memory 13 connected to each other. That is, in the thermal printer 100, the print density sensor control unit 27 controls the print density sensor 23 to acquire the print density distribution of the print screen 1a, and the correction thermal head control unit 26 based on the acquired print density distribution. And a processing circuit for calculating the amount of correction heat applied to the photographic paper 10a and heating the correction thermal head 21 with the calculated amount of correction heat. The above functions of the correction thermal head control unit 26 and the print density sensor control unit 27 are described as programs, and the programs are stored in the memory 13 as software or firmware. The processing circuit reads the program stored in the memory 13 and executes it by the CPU 12. Thereby, the operations of the correction thermal head control unit 26 and the print density sensor control unit 27 are realized. Note that the memory 13 is, for example, a volatile or nonvolatile semiconductor memory such as a RAM or a flash memory. In the first embodiment, each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25 is connected to the CPU 12, and each operation of each control unit is realized by the CPU 12. Each control unit may include each CPU individually, and each individual CPU may realize each operation in each control unit.

  The processing circuit included in the thermal printer 100 may be dedicated hardware. In this case, the processing circuit is, for example, a programmed processor or a parallel programmed processor. The processing circuit may be provided with a plurality of dedicated hardware corresponding to the functions of the correction thermal head control unit 26 and the print density sensor control unit 27, thereby realizing each operation of each unit, or one dedicated hardware. By providing, each operation may be realized collectively. Further, the thermal printer 100 realizes a part of each function and each operation of the correction thermal head control unit 26 and the print density sensor control unit 27 with dedicated hardware, and a part thereof with software or firmware. You may do it.

  In the first embodiment, as shown in FIG. 2, the curl correction apparatus control unit 25 includes a print density sensor control unit 27 and a correction thermal head control unit 26. This configuration is an example. . For example, the curl correction apparatus control unit 25 may include a control unit that collectively has the functions of the print density sensor control unit 27 and the correction thermal head control unit 26. The control unit may be connected to the correction thermal head 21 and the print density sensor 23 to control the above operation, and the operation may be realized by the above processing circuit.

  Further, the thermal printer control unit 11 further includes a print data receiving unit 14 connected to the memory 13. In the first embodiment, the print data receiving unit 14 is connected to the memory 13 via the CPU 12. The print data receiving unit 14 is connected to an external device and receives print data. The received print data is stored in the memory 13, for example, and the CPU 12 reads the print data from the memory 13 and processes it as necessary. The external device is, for example, a PC.

(Printing operation and curl correction operation)
FIG. 3 is a perspective view showing the configuration of the thermal printer according to the first embodiment, and is a view as seen from the printing screen 1a side of the printing paper 10a conveyed in the conveyance path 2, that is, the printing thermal head 3 side. . FIG. 4 is a flowchart showing the printing operation and the curl correction operation of the thermal printer 100. The printing operation and curl correction operation of the thermal printer 100 will be described with reference to FIGS.

  First, the print data receiving unit 14 inputs print data from an external device such as a PC (step S10). The input of the print data and the following print operation and curl correction operation are executed by, for example, a print instruction from the user. The printing thermal head control unit 15 calculates the amount of printing heat required for printing by each heating element included in the printing thermal head 3 based on the printing data received by the printing data receiving unit 14 (step S20). .

  The printing thermal head controller 15 causes each of the heating elements of the printing thermal head 3 to generate heat with the amount of printing heat calculated in step S20 (step S30). The amount of heat for printing based on the printing data is given to the printing paper 10a from the printing screen 1a side, and printing is executed on the printing screen 1a. At the time of printing, the photographic paper 10a is nipped by the pinch roller 5 and the grip roller 6 from the photographic paper roll 10, and is printed by the thermal print head 3 while being conveyed in the direction of arrow A in FIG. The conveyance operation of the photographic paper 10a is controlled by the drive system controller 17. The position sensor 7 measures the position of the photographic paper 10a under the control of the position sensor control unit 16, and the printing thermal head control unit 15 uses the position to grasp the position of the photographic paper 10a.

  The printed screen 1a after printing includes a printing density distribution. For example, as shown in FIG. 3, the print density distribution includes a low density area 1c having a relatively low print density and a high density area 1d having a higher print density than the low density area 1c. Further, the printed screen 1a after printing has a curl amount corresponding to the printing density distribution. For example, the curl amount of the high-concentration region 1d given a high heat amount is different from the curl amount of the low-concentration region 1c given a low heat amount.

  After step S30, the printing paper 10a is conveyed to the printing density sensor 23. The print density sensor 23 measures the print density distribution on the print screen 1a under the control of the print density sensor control unit 27 (step S40). For example, the print density sensor control unit 27 controls the print density sensor 23 so as to continuously measure the print density distribution on the photographic paper 10a conveyed in the conveyance path 2. The print density sensor 23 according to the first embodiment is a line sensor, and collectively measures the print density distribution in the width direction of the photographic paper 10a. The print density sensor control unit 27 outputs the print density distribution data measured by the print density sensor 23 to the correction thermal head control unit 26.

  After step S40, the correction thermal head control unit 26 performs correction necessary for each heating element included in the correction thermal head 21 to perform curl correction based on the print density distribution data measured by the print density sensor 23. The amount of heat is calculated (step S50). In the first embodiment, the correction thermal head 21 is a heating element array including a plurality of heating elements arranged in the width direction of the photographic paper 10a. Therefore, the correction thermal head control unit 26 includes the photographic paper described above. The amount of heat for correction of each heating element is calculated according to the print density distribution in the width direction 10a. The straightening thermal head control unit 26 calculates a voltage to be applied to each heating element based on each straightening heat amount. In the first embodiment, the correcting thermal head control unit 26 sets a higher applied voltage to the heating element facing the high concentration region 1d than the heating element facing the low concentration region 1c, so that the low concentration region 1c is set. An applied voltage lower than that of the heating element facing the high-concentration region 1d is set to the heating element facing to the high concentration region 1d.

  The relationship between the applied voltage set to each heating element of the thermal head 21 for correction and the print density measured by the print density sensor 23 is given by, for example, a predetermined table or a predetermined calculation formula. The expression is stored in the memory 13, for example. Then, the CPU 12 reads and uses these tables and calculation formulas as appropriate. That is, the correction thermal head control unit 26 uses the relationship between the applied voltage set to each heating element given by a predetermined table or a predetermined calculation formula and the print density distribution measured by the print density sensor 23. The amount of heat for correction is calculated. The correction thermal head control unit 26 controls the amount of heat so that the amount of heat for correction does not affect the coloring of the stamp screen 1a. For example, the amount of heat for correction that the thermal head 21 for correction gives to the printing paper 10a in step S50 is smaller than the amount of heat for printing that the thermal head 3 for printing gives to the printing paper 10a in step S30.

  Further, after step S40, the photographic paper 10a is conveyed to the correcting thermal head 21. This conveyance operation and the processing in step S50 may be executed in parallel.

  After step S50, the correction thermal head controller 26 causes each heating element of the correction thermal head 21 to generate heat with the correction heat amount calculated in step S50 (step S60). As a result, the amount of correction heat based on the print density distribution is applied to the photographic paper 10a from the back surface 1b side, and the curl correction processing is performed. In the first embodiment, the correction thermal head 21 applies a higher amount of heat to the high concentration region 1d than the low concentration region 1c, and applies a lower amount of heat to the low concentration region 1c than the high concentration region 1d. . In the first embodiment, the photographic paper 10a is heated by the correcting thermal head 21 while being conveyed in the conveyance path 2. Therefore, in order for the correction thermal head 21 to perform the curl correction processing according to the print density distribution in the transport direction, the correction thermal head control unit 26 determines the position in the transport direction of the printing paper 10 a and the correction thermal head 21. It is necessary to match the timing of heating each heating element. Control of the heating timing in the transport direction by the thermal head control unit 26 for correction may be controlled using the position data of the photographic paper 10a output from the position sensor control unit 16, or stored in the memory 13 in advance. The heating timing may be calculated and controlled from the installed position of the print density sensor 23, the installed position of the correction thermal head 21, and the conveyance speed of the photographic paper 10a. After the curl correction processing by the correction thermal head 21, the photographic paper 10a is conveyed to the position of the cutter 8, cut, and discharged from the discharge port 9 (step S70).

  As described above, in the first embodiment, the control of the printing operation and the curl correction operation by each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25 is described as a program in the memory 13 described above. Is realized by the CPU 12 executing. In addition, when each control part is provided with each CPU separately, each CPU may implement | achieve each operation | movement in each control part.

(effect)
In summary, the curl correction apparatus according to the first embodiment corrects the curl of the photographic paper 10a that is printed by the thermal head 3 for printing by heating the photographic paper 10a from the printing screen 1a side of the photographic paper 10a. A device that is provided on the conveyance path 2 that conveys the photographic paper 10a and the print screen 1a side or the back surface 1b side of the photographic paper 10a that is conveyed in the conveyance path 2 and that measures the characteristic distribution of the photographic paper 10a. A distribution measuring means, a heating means (correction thermal head 21) provided on the back surface 1b side of the photographic paper 10a conveyed in the conveyance path 2 and applying a correction heat quantity to the photographic paper 10a from the back surface 1b side; Heating control means (correction thermal head control unit 26) for controlling the amount of heat for correction based on the distribution is provided. With the configuration as described above, the curl correction apparatus reads the characteristic distribution of the photographic paper 10a after printing and calculates the optimum amount of correction heat. Therefore, even when the curl amount is not uniform in the plane of the photographic paper 10a, Correction according to the curl amount can be performed. As a result, the curl correction apparatus provides efficient and appropriate curl correction as compared to curl correction when uniform heat is applied. In addition, the curl correction apparatus described above can prevent the amount of heat necessary for correction from being applied to the photographic paper 10a and can reduce power consumption.

  Further, the characteristic distribution measuring means provided in the curl correction apparatus in the first embodiment is provided on the printing screen 1a side of the printing paper 10a conveyed in the conveyance path 2, and the printing density of the printing screen 1a included in the characteristic distribution. It further includes a print density distribution measuring means (print density sensor 23) for measuring the distribution, and the heating control means (correction thermal head control unit 26) controls the amount of heat for correction based on the print density distribution. With the configuration described above, the curl correction apparatus can perform curl correction according to the amount of heat for printing applied to the printing paper 10a by the printing thermal head 3 during printing. As a result, the curl correction apparatus can efficiently and appropriately correct the curl of the photographic paper 10a according to the curl amount generated by the heat amount at the time of printing.

  Further, the print density distribution measuring means (print density sensor 23) provided in the curl correction apparatus according to the first embodiment has a plurality of print density measuring elements in a line shape in the width direction of the printing paper 10a conveyed in the conveyance path 2. Are printed density measurement line sensors that measure the print density distribution in the width direction of the photographic paper 10a, and the heating means (correction thermal head 21) is arranged in the width direction of the photographic paper 10a conveyed in the conveyance path 2. A heating element array in which a plurality of heating elements are arranged in a line, and the heating control means (correction thermal head control unit 26) is arranged on the heating element array based on the print density distribution in the width direction of the photographic paper 10a. Each amount of correction heat applied to each included heating element is controlled. With the configuration as described above, the curl correction apparatus can perform curl correction not only according to the print density distribution in the conveyance direction of the photographic paper 10a but also according to the print density distribution in the width direction. As a result, the curl correction apparatus can accurately correct the curl generated in the surface of the photographic paper 10a for each position in the surface.

  The thermal printer 100 according to the first embodiment is provided on the printing screen 10a side of the printing paper 10a conveyed in the conveyance path 2 with the curl correction device, and heats the printing paper 10a from the printing screen 1a side. And a printing thermal head 3 capable of printing on the printing screen 1a. With the above-described configuration, the thermal printer 100 can perform correction according to the amount of curl in the surface of the photographic paper 10a generated at the time of printing, and provide a printed matter with a better finished quality with less curling than before. Make it possible.

<Embodiment 2>
The curl correction apparatus and the thermal printer in the second embodiment will be described. The description of the same configuration and operation as in the first embodiment is omitted.

(Configuration of curl correction device and thermal printer)
FIG. 5 is a cross-sectional view showing the configuration of the thermal printer 200 according to the second embodiment. Similar to the thermal printer 100 described in the first embodiment, the thermal printer 200 includes a curl correction device. The curl correction apparatus provided with the thermal printer 200 includes a distance sensor 24 instead of the print density sensor 23 described in the first embodiment in the characteristic distribution measurement apparatus that measures the characteristic distribution of the photographic paper 10a. In the second embodiment, the distance sensor 24 is arranged on the printing screen 1a side of the photographic paper 10a conveyed in the conveyance path 2. Other configurations included in the thermal printer 200 and the curl correction apparatus according to the second embodiment are the same as those of the thermal printer 100 and the curl correction apparatus described in the first embodiment.

  The distance sensor 24 is a distance distribution measuring unit that measures the distance distribution between the stamp screen 1 a and the distance sensor 24. In the second embodiment, the distance distribution between the printing screen 1a and the distance sensor 24 is a characteristic distribution of the photographic paper 10a. The distance corresponds to the amount of warp of the photographic paper 10a, that is, the curl amount. That is, the distance sensor 24 measures the amount of curl in the surface of the photographic paper 10a. The distance sensor 24 according to the first embodiment is a distance measuring line sensor in which a plurality of distance measuring elements are arranged in a line in the width direction of the photographic paper 10a, and the printing screen 1a in the width direction of the photographic paper 10a. And the distance to each distance measuring element are collectively measured. The distance sensor 24 or the distance measuring element is, for example, an optical sensor or an ultrasonic sensor. For example, the distance sensor 24 includes a semiconductor light emitting element or a semiconductor light receiving element. The distance sensor 24 in the second embodiment is provided on the printing screen 1a side of the photographic paper 10a conveyed in the conveyance path 2, but may be disposed on the back surface 1b side of the photographic paper 10a. In this case, the distance sensor 24 measures the distance between the back surface 1b of the photographic paper 10a and the distance sensor 24 as a characteristic distribution of the photographic paper 10a.

  FIG. 6 is a block diagram of the thermal printer control unit 11 provided in the thermal printer 200. The curl correction device built in the thermal printer 200 includes a curl correction device control unit 25, and the curl correction device control unit 25 is built in the thermal printer control unit 11. The curl correction apparatus control unit 25 includes a distance sensor control unit 28 instead of the print density sensor control unit 27 described in the first embodiment, and the distance sensor control unit 28 is connected to the distance sensor 24 to control the distance measurement operation. To do. Although the detailed control operation will be described later, the distance sensor control unit 28 controls the distance sensor 24 to acquire the distance distribution between the stamp screen 1a and the distance sensor 24, and the correction thermal head control unit 26 acquires the acquired distance distribution. Based on the above, the amount of correction heat applied to the photographic paper 10a is calculated, and the correction thermal head 21 is heated with the calculated amount of correction heat. The correction thermal head control unit 26 is an example of a heating control unit in the curl correction processing operation.

  Similarly to the first embodiment, the thermal printer 100 includes a processing circuit (not shown in detail) that realizes each control operation of each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25. The processing circuit includes a CPU 12 and a memory 13 connected to each other. That is, in the thermal printer 100, the distance sensor control unit 28 controls the distance sensor 24 to acquire the distance distribution between the stamp screen 1a and the distance sensor 24, and the correction thermal head control unit 26 is based on the acquired distance distribution. And a processing circuit for calculating the amount of heat for correction to be applied to the photographic paper 10a and heating the heat-correcting thermal head 21 with the calculated amount of heat for correction.

(Printing operation and curl correction operation)
FIG. 7 is an enlarged cross-sectional view of the vicinity of the printing thermal head 3 and the distance sensor 24 of the thermal printer 200. FIG. 8 is a flowchart showing the printing operation and curl correction operation of the thermal printer 200. The printing operation and curl correction operation of the thermal printer 200 will be described below with reference to FIGS.

  The printing operation from step S10 to step S30, that is, the printing operation on the printing screen 1a by the printing thermal head 3 is the same as in the first embodiment. After step S30, the photographic paper 10a is conveyed to the distance sensor 24. The photographic paper 10a is conveyed in the right direction in FIG. The distance sensor 24 measures the distance distribution between the stamp screen 1a and the distance sensor 24 under the control of the distance sensor control unit 28 (step S41). For example, the distance sensor control unit 28 controls the distance sensor 24 to continuously measure the distance distribution with respect to the photographic paper 10a conveyed in the conveyance path 2. The distance sensor 24 according to the second embodiment is a line sensor, and measures the distance distribution in the width direction of the photographic paper 10a at once. The distance sensor control unit 28 outputs the distance distribution data measured by the distance sensor 24 to the correction thermal head control unit 26.

  After step S41, the correction thermal head control unit 26 determines the amount of correction heat necessary for each heating element included in the correction thermal head 21 to perform curl correction based on the distance distribution data measured by the distance sensor 24. Calculate (step S51). In the second embodiment, the correcting thermal head 21 is a heating element array including a plurality of heating elements arranged in the width direction of the photographic paper 10a. Therefore, the correcting thermal head control unit 26 includes the photographic paper described above. The amount of heat for correction of each heating element is calculated according to the distance distribution in the width direction of 10a. The straightening thermal head control unit 26 calculates a voltage to be applied to each heating element based on each straightening heat amount.

  As shown in FIG. 7, the distance between the printing screen 1a measured by the distance sensor 24 and the distance sensor 24 is related to the curl amount of the photographic paper 10a. The distance D2 between the photographic paper 10a and the distance sensor 24 in the small curl area 1f having a smaller curl amount than the large curl area 1e is larger than the distance D1 in the large curl area 1e. Therefore, the correcting thermal head control unit 26 applies a higher applied voltage to the heating element facing the large curled area 1e having the distance D1 shorter than the distance D2 than to the heating element facing the small curled area 1f having the distance D2. Set. Further, the correcting thermal head control unit 26 applies a lower applied voltage to the heating element facing the small curled area 1f having the distance D2 longer than the distance D1 than the heating element facing the large curled area 1e having the distance D1. Set.

  The relationship between the applied voltage set to each heating element of the thermal head 21 for correction and the distance measured by the distance sensor 24 is given by, for example, a predetermined table or a predetermined calculation formula. Stored in the memory 13. Then, the CPU 12 reads and uses these tables and calculation formulas as appropriate. That is, the correction thermal head control unit 26 corrects using the relationship between the applied voltage set to each heating element given by a predetermined table or a predetermined calculation formula and the distance distribution measured by the distance sensor 24. Calculate the amount of heat used. The correction thermal head control unit 26 controls the amount of heat so that the amount of heat for correction does not affect the coloring of the stamp screen 1a. For example, the amount of heat for correction that the thermal head 21 for correction gives to the photographic paper 10a in step S51 is smaller than the amount of heat for printing that the thermal head 3 for printing gives to the photographic paper 10a in step S30. When the distance sensor 24 is installed on the back surface 1b side of the photographic paper 10a conveyed in the conveyance path 2, the distance between the distance measured by the distance sensor 24 and the amount of correction heat applied to the correction thermal head 21 is small or large. The relationship is reversed from the above relationship.

  Further, after step S41, the photographic paper 10a is conveyed to the correcting thermal head 21. This conveyance operation and the control in step S51 may be executed in parallel.

  After step S51, the correction thermal head controller 26 causes each heating element of the correction thermal head 21 to generate heat with the correction heat amount calculated in step S50 (step S61). Then, the amount of heat for correction based on the distance distribution is given to the photographic paper 10a from the back surface 1b side, and the curl correction processing is performed. In the second embodiment, the correction thermal head 21 applies a higher amount of heat to the large curled region 1e than the small curled region 1f, and applies a lower amount of heat to the small curled region 1f than the large curled region 1e. . Step S70 performed after step S61 is the same as that in the first embodiment.

  As described above, in the second embodiment, the control of the printing operation and the curl correction operation by the respective control units included in the thermal printer control unit 11 and the curl correction device control unit 25 are described as programs in the memory 13 described above. Is realized by the CPU 12 executing. In addition, when each control part is provided with each CPU separately, each CPU may implement | achieve each operation | movement in each control part.

(effect)
As described above, the characteristic distribution measuring means included in the curl correction apparatus according to the second embodiment further includes the distance distribution measuring means (distance sensor 24), and the distance distribution measuring means is a print conveyed in the conveyance path 2. The distance distribution between the printing screen 1a of the printing paper 10a and the distance distribution measuring means included in the characteristic distribution is provided on the printing screen 1a side of the paper 10a, or the printing paper 10a conveyed in the conveyance path 2 is measured. A distance distribution between the back surface 1b of the photographic paper 10a provided on the back surface 1b side and included in the characteristic distribution and the distance distribution measuring unit is measured, and the heating control unit (correction thermal head control unit 26) is based on the distance distribution. Control the amount of heat for correction. With the configuration described above, the curl correction apparatus can perform correction according to the curl amount originally possessed by the photographic paper in addition to the curl generated during printing. As a result, the curl correction apparatus can correct the curl of the photographic paper 10a efficiently and appropriately. Also, even if the storage history of the photographic paper 10a and the environmental conditions such as environmental temperature and humidity at the time of printing change, the curl correction device directly measures the curl amount of the photographic paper 10a after printing. The curl of the photographic paper 10a can be corrected.

  Further, the distance distribution measuring means (distance sensor 24) provided in the curl correcting apparatus according to the second embodiment has a plurality of distance measuring elements arranged in a line in the width direction of the photographic paper 10a conveyed in the conveying path 2. The distance measuring line sensor measures the distance distribution in the width direction of the photographic paper 10a, and the heating means (correction thermal head 21) includes a plurality of heating elements in the width direction of the photographic paper 10a conveyed in the conveyance path 2. Are heating element arrays arranged in a line, and the heating control means (correction thermal head control unit 26) applies each heating element included in the heating element array based on the distance distribution in the width direction of the photographic paper 10a. Control the amount of heat applied for each correction. With the configuration as described above, the curl correction apparatus can perform curl correction corresponding to each position in the width direction of the photographic paper 10a. As a result, the curl correction apparatus can accurately correct the curl generated in the surface of the photographic paper 10a for each position in the surface.

  The thermal printer 200 according to the second embodiment is provided on the printing screen 1a side of the curling correction device and the printing paper 10a conveyed in the conveyance path 2, and heats the printing paper 10a from the printing screen 1a side. And a printing thermal head 3 capable of printing on the printing screen 1a. With the above-described configuration, the thermal printer 200 can perform correction according to the curl amount originally possessed by the photographic paper in addition to the curl generated at the time of printing. Providing good prints. Further, even if the storage history of the photographic paper 10a before printing and the environmental conditions such as environmental temperature and humidity at the time of printing change, the curl correction device directly measures the curl amount of the photographic paper 10a after printing. Therefore, the thermal printer 200 can effectively and accurately correct the curling of the photographic paper 10a, and can provide a printed matter with a good finished quality with curling reduced as compared with the related art.

<Embodiment 3>
A thermal printer according to the third embodiment will be described. Note that the description of the same configuration and operation as in the first embodiment will be omitted. The thermal printer 100 described in the first embodiment uses the print density sensor 23 to measure the print density distribution in the plane of the print screen 1a. However, the thermal printer in the third embodiment has the print density distribution. Calculated from print data. FIG. 9 is a cross-sectional view showing the configuration of the thermal printer 300 according to the third embodiment. The thermal printer 300 does not need to include the print density sensor 23 which is a characteristic measuring unit of the printing paper 10a. Other configurations are the same as those of the thermal printer 100 of the first embodiment, and the correction thermal head 21 provided in the thermal printer 300 is a heating element in which a plurality of heating elements are arranged in a line shape in the width direction of the photographic paper 10a. An array.

  The CPU 12 processes the print data input by the print data receiving unit 14 and calculates the print density distribution in the plane of the print screen 1a. That is, the correction thermal head control unit 26 calculates a print density distribution from the print data, and calculates a correction heat amount to be applied to the photographic paper 10a based on the calculated print density distribution. The straightening thermal head controller 26 heats the straightening thermal head 21 with the calculated amount of straightening heat.

  The thermal printer 300 operates as described above, that is, the correction thermal head control unit 26 calculates the print density distribution from the print data, and calculates the correction heat amount to be applied to the photographic paper 10a based on the calculated print density distribution. A processing circuit for calculating and heating the correction thermal head 21 with the calculated amount of correction heat is included.

  FIG. 10 is a flowchart showing the printing operation and curl correction operation of the thermal printer 300. The printing operation of the thermal printer 300 is the same as that in the first embodiment from step S10 to step S30. In the third embodiment, the thermal printer 300 does not need to measure the print density of the print screen 1a. Therefore, step S40 shown in the first embodiment is not performed in the third embodiment. After step S30, the correction thermal head controller 26 determines the amount of correction heat applied by the correction thermal head 21 to the photographic paper 10a based on the print density for each in-plane position of the photographic paper 10a included in the print data. Calculate (step S52). The relationship between the applied voltage set to each heating element of the thermal head 21 for correction and the print density calculated from the print data is given by, for example, a predetermined table or a predetermined calculation formula. Stored in the memory 13. Then, the CPU 12 reads and uses these tables and calculation formulas as appropriate. That is, the correction thermal head control unit 26 corrects using the relationship between the applied voltage set to each heating element given by a predetermined table or a predetermined calculation formula and the print density distribution calculated from the print data. Calculate the amount of heat used. The correction thermal head control unit 26 controls the amount of heat so that the amount of heat for correction does not affect the coloring of the stamp screen 1a. Note that the timing of performing step S52 does not have to be after step S30, and may be performed at an appropriate timing until subsequent step S60 is performed.

  After step S52, the correction thermal head 21 performs the curl correction processing by applying the correction heat amount calculated in step S52 to the photographic paper 10a from the back surface 1b side (step S62). Step S70 performed after step S62 is the same as that in the first embodiment.

  As described above, in the third embodiment, the control of the printing operation and the curl correction operation by each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25 is described as a program in the memory 13 described above. Is realized by the CPU 12 executing. In addition, when each control part is provided with each CPU separately, each CPU may implement | achieve each operation | movement in each control part.

(effect)
As described above, the thermal printer 300 according to the third embodiment is provided on the conveyance path 2 that conveys the photographic paper 10a and the printing screen 10a that is conveyed in the conveyance path 2 and is input from the outside. The printing thermal head 3 capable of printing on the printing screen 1a by heating the printing paper 10a from the printing screen 1a side based on the printing data to be printed, and the back surface 1b side of the printing paper 10a conveyed in the conveyance path 2 Then, based on the heating means (correcting thermal head 21) for applying the correction heat quantity to the photographic paper 10a from the back surface 1b side, and the print density for each in-plane position of the photographic paper 10a included in the print data, the correction heat quantity. Heating control means (correction thermal head control unit 26). With the above-described configuration, the thermal printer 300 can perform curl correction according to the amount of heat for printing applied to the printing paper 10a by the printing thermal head 3 during printing. As a result, the curl correction apparatus can efficiently and appropriately correct the curl of the photographic paper 10a according to the amount of curl generated by the amount of heat at the time of printing. It can be provided.

  The heating means (correcting thermal head 21) provided in the thermal printer 300 according to the third embodiment has a plurality of heating elements arranged in a line in the width direction of the photographic paper 10a conveyed in the conveyance path 2. The heating element array, and the heating control means (correction thermal head control unit 26) controls each amount of correction heat applied to each heating element included in the heating element array based on the print density for each in-plane position. . With the above configuration, the thermal printer 300 can perform curl correction not only according to the print density distribution in the width direction but also in the conveyance direction of the photographic paper 10a. As a result, the curl correction apparatus can accurately correct the curl generated in the surface of the photographic paper 10a for each position in the surface, and provide a printed matter with a better finished quality with reduced curl than before. Make it possible.

<Embodiment 4>
A curl correction apparatus according to the fourth embodiment will be described. The thermal printer 100 described in the first embodiment or the thermal printer 200 described in the second embodiment incorporates a curl correction device. In the fourth embodiment, an example of a curl correction device independent of the thermal printer is shown. .

(Configuration of curl correction device)
FIG. 11 is a cross-sectional view showing a configuration of curl correction apparatus 400 in the present embodiment. The curl correction apparatus 400 is a curl correction apparatus that corrects curling of photographic paper that is printed by a thermal head of a thermal printer (not shown) heated from the printing screen side of the photographic paper. The curl correction apparatus 400 includes a conveyance path 2 through which the photographic paper 10a is conveyed. The curl correction apparatus 400 further includes a paper feed port 19 for introducing the photographic paper 10a from the outside to the transport path 2 and a paper discharge port 9 for discharging the photographic paper 10a from the transport path 2 to the outside. Further, the curl correction device 400 is used for the curl correction processing of the photographic paper 10a on the back surface 1b side opposite to the printing screen 1a and the printing density sensor 23 on the printing screen 1a side of the photographic paper 10a conveyed on the conveyance path 2. The thermal head 21 for correction is further provided as a heating means. The configurations of the print density sensor 23 and the correction thermal head 21 are the same as those in the first embodiment. In addition, the curl correction apparatus 400 further includes a platen roller 22 at a position facing the correction thermal head 21 with the conveyance path 2 interposed therebetween. Further, the curl correction apparatus 400 further includes a pinch roller 5 and a grip roller 6 at positions different from the correction thermal head 21 so as to face each other with the conveyance path 2 interposed therebetween. Further, the curl correction apparatus 400 further includes a position sensor 7 that detects a position of the photographic paper 10a in the transport direction. Each configuration provided in the curl correction apparatus 400 described above has the same functions as those in the first embodiment. The curl correction apparatus 400 according to the fourth embodiment does not include the thermal print head 3 included in the thermal printer 100 according to the first embodiment.

  FIG. 12 is a block diagram of the curl straightening device control unit 25 provided in the curl straightening device 400. The curl correction device control unit 25 further includes a position sensor control unit 16 that is connected to the position sensor 7 and controls the operation of the position sensor 7. In addition, the curl correction device control unit 25 further includes a drive system control unit 17 that is connected to the pinch roller 5 and the grip roller 6 and controls the drive thereof. The curl correction device control unit 25 is connected to the correction thermal head 21 and connected to the correction thermal head control unit 26 for controlling the heating operation in the curl correction process and the print density sensor 23 to control the print density measurement operation. And a print density sensor control unit 27. Although the detailed control operation of each control unit will be described later, the print density sensor control unit 27 controls the print density sensor 23 to acquire the print density distribution of the print screen 1a, and the correction thermal head control unit 26 acquires the print density distribution. Based on the print density distribution, the amount of correction heat applied to the photographic paper 10a is calculated, and the correction thermal head 21 is heated with the calculated amount of correction heat.

  Further, the curl correction apparatus 400 includes a processing circuit (not shown in detail) for realizing each control operation of each control unit included in the curl correction apparatus control unit 25. The processing circuit includes a CPU 12 and a memory 13 connected to each other. That is, in the curl correction apparatus 400, the print density sensor control unit 27 controls the print density sensor 23 to acquire the print density distribution of the print screen 1a, and the correction thermal head control unit 26 based on the acquired print density distribution. And a processing circuit for calculating the amount of heat for correction to be applied to the photographic paper 10a and heating the heat-correcting thermal head 21 with the calculated amount of heat for correction.

(Curl correction operation of the curl correction device)
FIG. 13 is a flowchart showing the curl correction operation of the curl correction apparatus 400. Hereinafter, the curl correcting operation of the curl correcting apparatus 400 will be described with reference to FIGS.

  First, the photographic paper 10a is fed into the transport path 2 from the paper feed port 19 with the print screen 1a facing the print density sensor 23 (step S11). The photographic paper 10 a is conveyed while being sandwiched between the pinch roller 5 and the grip roller 6, and reaches the print density sensor 23. These transport operations are controlled by the drive system controller 17. After step S11, the print density sensor 23 measures the print density of the print screen 1a under the control of the print density sensor control unit 27 (step S40). Thereafter, the curl correcting operation performed by the curl correcting apparatus 400 from step S40 to step S70 is the same as that in the first embodiment.

  As described above, the control of the printing operation and the curl correction operation by each control unit included in the thermal printer control unit 11 and the curl correction device control unit 25 is described as a program in the memory 13 described above, and is realized by the CPU 12 executing the program. Is done. In addition, when each control part is provided with each CPU separately, each CPU may implement | achieve each operation | movement in each control part.

(effect)
In summary, the curl correcting apparatus 400 according to the fourth embodiment curls the curling of the photographic paper 10a printed by the photographic printing head 10a by heating the photographic paper 10a from the printing screen 1a side of the photographic paper 10a. A correction device, provided on the side of the printing screen 1a of the photographic paper 10a conveyed in the conveyance path 2 and the conveyance path 2 that conveys the photographic paper 10a, and measures the characteristic distribution (print density distribution) of the photographic paper 10a. Characteristic distribution measuring means (print density sensor 23) for heating and heating means (correction) provided on the back surface 1b side of the photographic paper 10a conveyed in the conveyance path 2 and applying a correction heat quantity to the photographic paper 10a from the back surface 1b side. Thermal head 21) and heating control means (correcting thermal head controller 26) for controlling the amount of heat for correction based on the characteristic distribution. With the configuration as described above, the curl correction apparatus 400 can correct the curl of the photographic paper printed by the thermal printer without being incorporated in the thermal printer. For example, the same effect as that of the first embodiment can be obtained by connecting the paper feed port 19 of the curl correction apparatus 400 to the paper discharge port of an existing thermal printer. In the fourth embodiment, the curl correction apparatus 400 includes the print density sensor 23 in the characteristic distribution measuring unit. However, as in the second embodiment, the curl correction apparatus 400 includes a distance sensor on the print screen 1a side or the back surface 1b side. Also good. Such a curl correction device has the same effect as that of the second embodiment.

  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.

  1a printing screen, 1b back surface, 2 transport path, 3 printing thermal head, 10a printing paper, 21 correction thermal head, 23 printing density sensor, 24 distance sensor, 25 curl correction device control unit, 26 correction thermal head control unit 27, print density sensor control unit, 28 distance sensor control unit, 100 thermal printer, 200 thermal printer, 300 thermal printer, 400 curl correction device.

Claims (8)

A curl correcting device that corrects curling of the photographic paper printed by heating the photographic paper from the printing screen side,
A conveyance path for conveying the photographic paper;
A characteristic distribution measuring means for measuring a characteristic distribution of the photographic paper, provided on the printing screen side or the back side of the photographic paper conveyed in the conveyance path;
A heating unit that is provided on the back side of the photographic paper transported in the transport path and applies a heat amount to the photographic paper from the back side;
A curl correction apparatus comprising: a heating control unit that controls the amount of heat based on the characteristic distribution. The characteristic distribution measuring unit further includes a print density distribution measuring unit that is provided on the printing screen side of the printing paper conveyed in the conveyance path and that measures the printing density distribution of the printing screen included in the characteristic distribution. Including
The curl correction apparatus according to claim 1, wherein the heating control unit controls the amount of heat based on the print density distribution. The printing density distribution measuring unit measures the printing density distribution in the width direction of the photographic paper by arranging a plurality of printing density measuring elements in a line in the width direction of the photographic paper conveyed in the conveyance path. Print density measurement line sensor
The heating means is a heating element array in which a plurality of heating elements are arranged in a line in the width direction of the photographic paper transported in the transport path,
The curl correction apparatus according to claim 2, wherein the heating control unit controls the amount of heat applied to each of the heating elements included in the heating element array based on the print density distribution in the width direction of the photographic paper. . The characteristic distribution measuring means further includes a distance distribution measuring means,
The distance distribution measuring means is provided on the printing screen side of the photographic paper conveyed in the conveying path, and the distance distribution between the printing screen of the photographic paper included in the characteristic distribution and the distance distribution measuring means. Or measuring the distance distribution between the back surface of the photographic paper and the distance distribution measuring means included in the characteristic distribution provided on the back surface side of the photographic paper transported in the transport path,
The curl correction apparatus according to any one of claims 1 to 3, wherein the heating control unit controls the amount of heat based on the distance distribution. The distance distribution measuring means is a distance measurement line for measuring the distance distribution in the width direction of the photographic paper in which a plurality of distance measuring elements are arranged in a line shape in the width direction of the photographic paper conveyed in the conveyance path. Sensor,
The heating means is a heating element array in which a plurality of heating elements are arranged in a line in the width direction of the photographic paper transported in the transport path,
The curl correction apparatus according to claim 4, wherein the heating control unit controls the amount of heat applied to each of the heating elements included in the heating element array based on the distance distribution in the width direction of the photographic paper. The curl correction device according to any one of claims 1 to 5,
A thermal printer provided with the thermal head provided on the printing screen side of the printing paper conveyed in the conveyance path and capable of printing on the printing screen by heating the printing paper from the printing screen side. A transport path for transporting photographic paper;
A thermal head which is provided on the printing screen side of the photographic paper conveyed in the conveyance path and which can print on the printing screen by heating the photographic paper from the printing screen side based on printing data input from the outside. When,
A heating unit that is provided on the back side of the printing screen of the photographic paper transported in the transport path, and applies a heat amount to the photographic paper from the back side;
A thermal printer, comprising: a heating control unit that controls the amount of heat based on a printing density for each in-plane position of the printing paper included in the printing data. The heating means is a heating element array in which a plurality of heating elements are arranged in a line in the width direction of the photographic paper transported in the transport path,
The thermal printer according to claim 7, wherein the heating control unit controls each amount of heat applied to each of the heating elements included in the heating element array based on the print density for each in-plane position.

Images