JP2010201736A - Sublimation type printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sublimation type printer that makes a dot print processing mark on a surface inconspicuous, thereby improving the quality of a print on the surface, and furthermore, prevents variation in the density of a print on a back, which results from a dot print process. <P>SOLUTION: The sublimation type printer 1 includes a surface printing section 3 for performing a sublimation print process on the surface of the paper S, and a back printing section 4 for performing the dot print process on the back of paper S. In this printer 1, a dot print power supply time, which is the time for which a dot pin 41a is pressed against the back of the paper S is the one in which a basal power supply time, which is a power supply time that should be essentially ensured, is corrected by a first correcting power supply time determined based on the density of an image printed on the surface of the paper S by the surface printing section 3 and a second correcting power supply time determined based on the temperature of the periphery of the back printing section 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sublimation type printer that performs sublimation print processing on the front surface of a sheet and performs dot print processing on the back surface.

  2. Description of the Related Art Conventionally, there is known a sublimation type printer in which ink is sublimated by applying heat to an ink ribbon with a thermal head, and the ink is adhered to a paper coated with, for example, a polyester resin. This type of sublimation printer can finely change the print density by controlling the heat applied to the thermal head, and can express continuous tone that is difficult in other printing methods.

  On the other hand, a printer configured to print incidental information such as information on the content printed on the front side of the paper on the back side of the paper by a dot impact print (hereinafter referred to as “dot print”) process is also considered. (See Patent Document 1). As is well known, in the dot print process, a dot print head having a plurality of dot pins arranged vertically and horizontally is positioned on the back surface side of the paper, and the pressure on the back surface of the paper is struck with the dot pins via the ink ribbon. In this process, printing is performed by attaching ink to the back surface of the paper. Each dot pin is controlled by the control unit so as to move into and out of the paper (advance / retreat operation).

Japanese Patent Laid-Open No. 10-90805

  As a sublimation type printer capable of performing sublimation print processing on the surface of paper by the above-described sublimation print method, a new type of sublimation printer having a back surface print function for performing dot print processing on the back surface of paper by the dot print method. When the present inventors repeated trial and error toward commercialization of the following, the following problems occurred.

  The first problem is that when dot printing processing is performed in which the dot pin is pressed against the back surface of the paper and local pressure is applied, the dot printing processing is performed on the front surface Sa ′ of the paper S ′ as shown in FIG. There is a case where the mark m (hereinafter referred to as “dot print process mark”) is conspicuous, and the quality of the surface print that is finished with high quality by the sublimation printer process can be lowered.

  In view of such problems, the present invention provides a sublimation-type printer that performs surface printing by sublimation printing processing and backside printing by dot printing processing, making the dot printing processing traces that appear on the surface of the paper inconspicuous, An object of the present invention is to provide a sublimation type printer capable of improving the print quality.

  The present inventors have pondered the above-described problems and conducted intensive studies on the control of the back surface printing by the dot printing process. As a result, they have found the following points.

  In other words, even when the dot pin energization time during the dot printing process, that is, the time for pressing the dot pin against the back side of the paper is the same, if a dark gradation (black) image is printed on the front side of the paper, It has been found that while the print processing trace is conspicuous, the dot print processing trace is not conspicuous when an image with a thin gradation is printed on the surface. Note that the energization time of the dot pin is equal to or substantially equal to the time (strobe time) in which the strobe signal is applied to the dot print head (specifically, the dot pin).

  The sublimation type printer of the present invention has been devised based on such knowledge.

  That is, the sublimation printer of the present invention includes a surface print unit that performs sublimation print processing on a surface of the paper by pressing an ink ribbon against the surface of the paper with a thermal head and heating the surface. A dot print head, and a back surface print unit having a control unit that controls a dot print energization time, which is a time for pressing the dot pin against the back surface of the paper, and the back surface print unit performs dot printing based on the dot print energization time. This is a sublimation type printer in which dot printing processing is performed on the back surface by pressing a pin against the back surface of the paper. In such a sublimation type printer, the controller prints the basic energization time, which is the energization time to be ensured in order to establish the dot print processing by the back surface print unit, on the image printed on the surface of the paper by the front surface print unit or Correction is performed by the first correction energization time determined based on the density of the front surface printed image, which is an image printed on the surface of the paper, and the operation of the dot pin is controlled using this corrected time as the dot print energization time. It is characterized by.

  As described above, the sublimation printer of the present invention is based on the above-described knowledge, and the energization time of the dot pin, which is constant in the conventional dot printer, is used as a parameter by the image printed on the surface of the paper by the front surface printing unit. By adopting the new technical idea of correcting, it is possible to suppress the occurrence of dot print processing marks on the surface of the paper and improve the quality of the surface print. In addition, in a mode in which dot printing processing by the back surface printing unit is performed after the sublimation printing processing by the front surface printing unit, the “front surface printing image” means an image printed on the surface of the paper by the front surface printing unit, and the first correction The energization time is determined based on the density of the image printed on the surface of the paper by the front surface printing unit. On the other hand, if the dot print process is performed by the back surface print unit before the sublimation print process by the front surface print unit, the “front surface print image” means an image printed on the surface of the paper by the front surface print unit. The correction energization time is determined based on the density of the image printed on the surface of the paper by the front surface printing unit. In the sublimation printer according to the present invention, in the relationship between the dot pin and the paper, only the dot pin moves in a direction in which the dot pin comes in contact with and separates from the paper, and in which the paper moves in a direction in which the paper comes in contact with and separates from the dot pin Any of these embodiments is also included.

  In addition, as a sublimation type printer that can perform sublimation print processing on the surface of paper by the sublimation printing method, a new type of sublimation printer that has a back surface printing function that performs dot print processing on the back surface of paper by the dot printing method. As a result of repeated trials by the present inventors toward commercialization, the density of the back surface printing due to the dot printing process varied, and the problem that the quality of the back surface printing was not constant (second problem) occurred. . And, as a result of studying the above-mentioned problems and intensively studying the control of the back surface printing by the dot printing process, the present inventors have found that the second problem is the temperature condition at the time of performing the dot printing process. I found that had a big influence. Specifically, it has been found that even when the energization time of the dot pins is the same, the concentration is high (high) in a high temperature environment and low (light) in a low temperature environment. Furthermore, the present inventors have found that the density of the backside print by the dot print process varies depending on the energization time of the dot pin. Specifically, if the energization time of the dot pin is long, the backside print by the dot print process It has also been found that the density of the back surface printed by the dot printing process decreases if the density increases and the dot pin energization time is short.

  Therefore, in the sublimation type printer of the present invention, the control unit sets the basic energization time, the above-described first correction energization time, and the density of the image printed on the front surface of the paper or the back surface at the time of the dot print process or immediately before the dot print process. It is also possible to control the operation of the dot pin using the time corrected by the second correction energization time determined based on the temperature around the print unit as the dot print energization time. In such a sublimation type printer, based on the above-described knowledge, in addition to the image printed on the surface of the paper by the surface print unit, the energization time of the dot pin, which was constant in the conventional dot printer, By adopting a new technical idea of correcting the density of the image printed on the paper surface and the temperature around the back printed part at the time of the dot printing process or immediately before the dot printing process as a parameter, dots are printed on the paper surface. It is possible to improve the quality of the front surface print by suppressing the occurrence of print processing traces, and to improve the quality of the back surface print by suppressing variations in the density of the back surface print.

  If the control unit obtains the dot print energization time by a simple calculation process, it contributes to reducing the burden on the control unit and improving the processing speed. From this point of view, in the sublimation printer of the present invention, the control unit is set to control the operation of the dot pin using the time corrected by adding the first correction energization time to the basic energization time as the dot print energization time. In addition, it is preferable that the dot pin energization time be set to control the operation of the dot pin with the time corrected by adding the first correction time and the second correction energization time to the basic energization time.

  In such a sublimation printer, when determining the first correction energization time, the density of the surface print image itself is directly detected, and the first correction energization time is determined based on the detected density of the surface print image itself. However, as a preferred embodiment for determining the first correction energization time by an approach different from this, the first correction energization time is the gradation value of the surface print image which is a factor for determining the density of the surface print image. And a mode determined based on the temperature of the thermal head of the front surface print unit or the temperature of the sublimation printer itself. Here, in the case where the dot print process is performed by the back surface print unit after the sublimation print process by the front surface print unit, the “tone value of the front surface print image” is the level of the image printed on the surface of the paper by the front surface print unit. This means a tone value, and if it is an aspect in which dot printing processing is performed by the back surface printing unit before sublimation printing processing by the front surface printing unit, the “tone value of the front surface printing image” is printed on the surface of the paper by the front surface printing unit. Means the gradation value of the image. In the sublimation printer of the present invention, the first correction energization time is determined based on the gradation value of the surface print image which is a factor for determining the density of the surface print image, the temperature of the thermal head of the surface print portion, and the temperature of the sublimation printer itself. , An aspect defined based on only one of these three factors (parameters), an aspect defined based on two requirements (parameters), or an aspect defined based on these three factors (parameters), these Any aspect is included.

  Further, in such a sublimation printer, when determining the second correction energization time, the temperature itself around the back surface printed portion at the time of the dot print processing by the back surface print portion or immediately before the dot print processing is directly detected, and the detected temperature itself The second correction energization time may be determined based on the second correction energization time, but as a preferred embodiment for determining the second correction energization time by an approach different from this, the second correction energization time may be set at the time of dot print processing or There is a mode in which the temperature is determined based on the temperature of the dot print head, which is a factor for determining the temperature around the back surface print portion immediately before the dot print processing, the temperature of the sublimation printer itself, or the temperature of the paper. Here, in the sublimation printer of the present invention, the second correction time is determined by the temperature of the dot print head, which is a factor that determines the temperature around the back surface print unit at the time of the dot print process or immediately before the dot print process, the sublimation printer itself. Mode determined based on temperature, paper temperature, one of these three factors (parameters), mode determined based on two requirements (parameters), or based on these three factors (parameters) And any of these aspects.

  Furthermore, after performing the sublimation printing process by the front surface printing unit, if the sublimation type printer that performs the dot printing process by the back surface printing unit, the temperature of the paper when performing the dot printing process or immediately before performing the dot printing process, Considering this point, the temperature of the paper, which is one parameter for determining the second correction energization time, is set to the temperature of the paper before the sublimation printing process. It may be determined based on the amount of heat given to the paper by the sublimation printing process.

  According to the sublimation type printer of the present invention, by correcting the dot print energization time based on the image printed on the surface of the paper by the sublimation print processing, it is possible to suppress the occurrence of dot print processing traces on the surface of the paper. The surface print quality can be improved. In addition, by correcting the dot print energization time based on the environmental temperature around the back surface print unit at the time of the dot print process or immediately before the dot print process, it is possible to suppress variations in the density of the back surface print due to the dot print process, It is also possible to improve the quality of the backside print.

1 is a schematic configuration diagram of a sublimation printer according to an embodiment of the present invention. FIG. 2 is an overall perspective view of the sublimation printer according to the embodiment. The figure which looked at the paper printed by the sublimation type printer concerning the embodiment from the surface side. The figure which looked at the paper printed by the sublimation type printer concerning the embodiment from the back side. FIG. 3 is a functional block diagram of a surface print control unit in the sublimation printer according to the embodiment. The functional block diagram of the back surface print control part in the sublimation type printer which concerns on the same embodiment. FIG. 4 is a view showing a sheet on which the dot print marks are conspicuous on the surface, corresponding to FIG. 3.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 4, the sublimation printer 1 according to the present embodiment performs a sublimation print (see FIG. 3) process on the front surface Sa of the paper S, and the back surface Sb of the paper S. A dot print (see FIG. 4) process is performed. As shown in FIG. 1, the sublimation printer 1 includes a paper feed unit 2, a surface print unit 3 that performs a sublimation print process on the surface Sa of the paper S supplied from the paper feed unit 2, and a paper S A back surface print unit 4 that performs dot print processing on the back surface Sb and a paper discharge unit 5 (specifically, a paper discharge port 5 shown in FIG. 2) are provided. In the present embodiment, the front surface print unit 3 is provided on the paper feed unit 2 side, and the back surface print unit 4 is provided on the paper discharge unit 5 side. That is, the sublimation printer 1 according to the present embodiment first performs sublimation printing processing on the front surface Sa of the paper S by the front surface printing unit 3, and then performs dot printing processing on the rear surface Sb of the paper S by the back surface printing unit 4. is there. As shown in FIG. 2, the sublimation printer 1 includes a paper feed unit 2, a front surface print unit 3, a back surface print unit 4, a paper discharge unit 5, and a paper transport mechanism, which will be described later, in a common housing C. 6 is provided.

  The paper feed unit 2 can accommodate the paper S wound in a roll shape. The sublimation printer 1 according to the present embodiment transports the paper S accommodated in a roll shape in the paper feed unit 2 along a transport path formed between the paper feed unit 2 and the paper discharge unit 5. A paper transport mechanism 6 is provided. In the following description, “upstream side” means “sheet feeding unit side”, and “downstream side” means “sheet discharge unit side”.

  The paper transport mechanism 6 includes an upstream transport mechanism 61 that transports the paper S mainly from the paper feed unit 2 toward the downstream side of the front surface print unit 3, and a paper discharge unit 5 mainly from the downstream side of the front surface print unit 3. And a downstream side transport mechanism 62 for transporting toward the rear.

  The upstream transport mechanism 61 includes a pair of a paper feed roller 611 and an upstream first pinch roller 612 arranged in order from the paper feed unit 2 side to the paper discharge unit 5 side, and an upstream feed roller 613 and an upstream side The two-pinch roller 614 is used in combination. A set of the paper feed roller 611 and the upstream first pinch roller 612 is arranged upstream of the front surface printing unit 3, and a set of the upstream feed roller 613 and the upstream second pinch roller 614 is from the front surface printing unit 3. Is also arranged downstream. Note that FIG. 1 shows a mode in which a paper feed guide roller 615 is disposed further upstream than the paper feed roller 611.

  The downstream side transport mechanism 62 includes a set of a downstream side feed roller 621 and a downstream side first pinch roller 622 arranged in order from the front surface printing unit 3 side toward the paper discharge unit 5 side, and a paper discharge roller 623. This is configured using a pair with the downstream second pinch roller 624. A set of the downstream feed roller 621 and the downstream first pinch roller 622 is arranged on the upstream side of the back surface printing unit 4, and a set of the paper discharge roller 623 and the downstream side second pinch roller 624 is from the back surface printing unit 4. Is also arranged downstream. Further, the sublimation printer 1 according to the present embodiment includes the cutter unit 7 that cuts the paper S between the downstream feed roller 621 and the downstream first pinch roller 622 and the back surface print unit 4.

  The front surface printing unit 3 transports the thermal head 31, the platen roller 32 disposed at a position facing the thermal head 31, the ink ribbon 33, and the ink ribbon 33 between the thermal head 31 and the platen roller 32. An ink ribbon transport mechanism 34 and a front surface print control unit 35 (not shown in FIG. 1 and refer to FIG. 5) for controlling the operation of at least the thermal head 31 are provided.

  The thermal head 31 is a known one that prints on the paper S by generating heat from a heating element (not shown). In this embodiment, the thermal head 31 is set so as to be movable between a position where the paper S can be sandwiched between the platen roller 32 and a position where the thermal head 31 cannot be sandwiched by a head drive motor (not shown).

  The platen roller 32 can sandwich the paper S with the thermal head 31, and has a function of sequentially transporting the paper S to the downstream side while rotating. Accordingly, the platen roller 32 serves as a part of the upstream transport mechanism 61 described above.

  The ink ribbon 33 is obtained by applying, for example, yellow, magenta, and cyan inks to a long base film. The yellow, magenta, and cyan inks applied to the base film are formed using a dye that sublimes by heat.

  The ink ribbon transport mechanism 34 includes a supply-side ribbon core 341 around which an unused ink ribbon 33 (in which a base film is coated with ink) is wound, and a used ink ribbon 33 (part of ink from the base film or A ribbon-side ribbon core 342 that winds up), a supply-side ribbon guide 343 that guides the ink ribbon 33 unwound from the supply-side ribbon core 341 to the thermal head 31 side, and after passing through the thermal head 31 A take-up ribbon guide 344 for guiding the ink ribbon 33 peeled from the paper S toward the take-up ribbon core 342 is provided. The supply side ribbon core 341 and the supply side ribbon guide 343 are arranged on the downstream side of the thermal head 31, and the take-up side ribbon core 342 and the take-up side ribbon guide 344 are arranged on the upstream side of the thermal head 31. Therefore, the ink ribbon 33 wound around the supply-side ribbon core 341 is unwound to the thermal head 31 side by the supply-side ribbon guide 343 and the take-up side ribbon guide 344, and is subjected to the sublimation printing process, and then the take-up side. The ribbon core 342 is sequentially wound up. In this embodiment, the ink ribbon 33 and the ink ribbon transport mechanism 34 are unitized and configured to be detachable from the thermal head 31 and the platen roller 32.

  The front surface printing unit 3 constituted by each unit has a function of printing (forming) a color image on the front surface Sa of the paper S by sublimating each color ink of yellow, magenta, and cyan by the heat of the thermal head 31. Demonstrate. The front surface print unit 3 can perform gradation printing in which the print density level is changed by adjusting the temperature of the thermal head 31, and prints a high-quality color image on the front surface Sa of the paper S. It is possible. Specifically, when the temperature of the thermal head 31 is high, the density of the image printed on the surface Sa of the paper S is relatively high and becomes a dark gradation, while when the temperature of the thermal head 31 is low, the density is relatively high. The density of the image printed on the front surface Sa of the paper S becomes low and the gradation becomes light.

  Temperature adjustment and operation of the thermal head 31 are controlled by the front surface print control unit 35. The front surface print control unit 35 is configured according to a program stored in an internal memory or an external storage device provided in the sublimation printer 1 and each component or element such as a CPU of a microprocessor provided in the sublimation printer 1. 5, as shown in FIG. 5, image information storage means 351 for storing information on an image to be printed on the surface Sa of the paper S temporarily or in a rewriteable manner, and stored in the image information storage means 351. The thermal head temperature control means 352 for adjusting the temperature of the thermal head 31 by setting the energization time of the thermal head 31 based on the information relating to the image being held, and the position where the paper S can be sandwiched between the thermal head 31 and the platen roller 32 At least a function as a thermal head movement control means 353 for moving between a position where it cannot be sandwiched Those having.

  On the other hand, as shown in FIG. 1, the back surface print unit 4 includes a dot print head 41 having a plurality of dot pins 41 a, a plastic template 42 disposed at a position facing the dot print head 41 across the paper S, The apparatus includes an ink ribbon 43 and a back surface print control unit 44 (corresponding to a “control unit” in the present invention, not shown in FIG. 1, but refer to FIG. 6) that controls at least the protrusion and subtraction operation of the dot pin 41a. is there.

  The dot print head 41 includes a head main body 41b and a plurality of dot pins 41a (for example, nine lines in this embodiment) arranged in a single row or matrix on the head main body 41b, and prints on the back surface Sb of the paper S. A predetermined dot pin 41a selected according to a character, a symbol, or the like to be projected can protrude in a direction approaching the paper S. In other words, each dot pin 41a can project and retract in a direction in which the dot pin 41a approaches and separates from the paper S. In FIG. 1, the dot print head 41 is schematically shown in order to clearly show the dot pin 41a in the protruding state.

  The plastic template 42 can sandwich the paper S with the dot print head 41. The platen roller 32 of the present embodiment is between a pressing position where the paper S can be sandwiched between the dot print head 41 and a retracted position where the paper S is retracted to a position where the paper S cannot be sandwiched between the dot print head 41. In the case where the back side printing process is performed, it is positioned at the pressing position, and when the back side printing process is not performed, it is positioned at the retracted position.

  The ink ribbon 43 is obtained by applying, for example, black ink to a base film. The ink ribbon 43 is conveyed by an ink ribbon conveyance mechanism (not shown) so that the ink ribbon 43 can pass (slide) on the tip of the dot print head 41. When the paper S passes above the ink ribbon 43, the dot pin 41a is projected to press the ink ribbon 43, and ink is attached to the back surface Sb of the paper S to print additional information such as characters and symbols. . Each time the dot printing process is completed, the used (engraved) ink ribbon 43 is wound around a take-up ribbon core (not shown), and the wound ink ribbon 43 is fed from a supply-side ribbon core (not shown). It is configured to be supplied and face the dot print head 41. That is, the ink ribbon 43 is used repeatedly until the ink runs out.

  The back surface print control unit 44 stores each component and each element such as a microprocessor CPU provided in the sublimation printer 1 in accordance with a program stored in the internal memory or external storage device provided in the sublimation printer 1. By operating, as shown in FIG. 6, the auxiliary information storage unit 441 and the auxiliary information storage unit 441 store the information related to the auxiliary information to be printed on the back surface Sb of the paper S temporarily or in a rewritable manner. The dot pin 41a to be protruded is selected based on the information related to the attached information, and the dot pin protrusion / retraction control means 442 for controlling the protrusion / retraction operation of the selected dot pin 41a, the dot pin 41a is pressed against the back surface Sb of the paper S. The function as the dot print energization time control means 443 for controlling the dot print energization time, which is the time, is small. Those having also.

  In the sublimation printer 1 according to the present embodiment, the back surface print control unit 44 uses the dot print energization time control unit 443 to perform the energization time that should be ensured during the dot print process, in other words, the dot print process by the back surface print unit. The first energization time determined based on the density of the image printed on the front surface Sa of the paper S by the front surface print unit 3 is set as the basic energization time. In addition, the second correction energization time determined based on the temperature is added to correct the dot print energization time (dot print energization time correction means 444).

  The “first correction energization time determined based on the density of an image printed on the front surface Sa of the paper S by the front surface print unit 3 (hereinafter referred to as“ front surface print image ”) is, so to speak, the front surface print unit 3. Is a correction value corresponding to the time during which the signal for generating heat from the thermal head 31 is given (in other words, the energization time to the thermal head 31). The correction energization time is determined based on the temperature of the thermal head 31 to be configured and the temperature of the sublimation printer 1 itself. As described above, if the temperature of the thermal head 31 is increased, the density of the surface print image is relatively high and shows a deep (high) gradation value, while if the temperature of the thermal head 31 is decreased, the surface print image is relatively relatively high. Is low and shows a light (low) gradation value. From this, when the density of the surface print image is high, the gradation value of the surface print image and the temperature of the thermal head 31 are also relatively high, and the temperature of the thermal head 31 is high, which means that the temperature of the sublimation printer 1 itself is high. Can be grasped as a relatively high relationship. On the other hand, when the density of the surface print image is low, the gradation value of the surface print image and the temperature of the thermal head 31 are relatively low, and the temperature of the thermal head 31 is low, which means that the temperature of the sublimation printer 1 itself is also relative. Can be grasped. Therefore, it is possible to indirectly grasp the density of the surface print image by detecting the gradation value of the surface print image, the temperature of the thermal head 31 constituting the surface print unit 3, and the temperature of the sublimation printer 1 itself. it can.

  In the present embodiment, the gradation value of the front surface print image is acquired from information about the image stored in the image information storage unit 351 of the front surface print control unit 35, and the temperature of the thermal head 31 and the temperature of the sublimation printer 1 itself are acquired. Are detected and acquired by a temperature detection unit (not shown) such as a thermistor provided individually.

  The sublimation printer 1 according to the present embodiment uses the dot print energization time correction unit 444 in the back surface print control unit 44 to set the tone value of the front surface print image, the temperature of the thermal head 31, and the temperature of the sublimation printer 1. A table corresponding to or closest to the detected tone value of the surface print image, the temperature of the thermal head 31 and the temperature of the sublimation printer 1 is referred to (selected) from a plurality of tables (not shown) as parameters. To set the first correction energization time. The plurality of tables using the tone value of the front surface print image, the temperature of the thermal head 31 and the temperature of the sublimation printer 1 as parameters are predetermined recordings such as an internal memory or an external storage device in the sublimation printer 1. Stored on the device.

  Here, the reason why the present inventors have come up with the necessity of correcting the dot print energization time based on the density of such a surface print image is as follows.

  That is, as a result of searching for the cause of the problem that a dot print process mark (hereinafter referred to as “dot print process mark”) is conspicuous on the surface Sa of the paper S, the present inventors have found that the dot pin 41a is Even when the energization time, that is, the time for pressing the dot pin 41a against the back surface Sb of the paper S is the same, the dot is not printed when a dark gradation image, that is, a high density image is printed on the front surface Sa. It has been found that while the print processing traces are conspicuous, the dot print processing traces are difficult to be noticed when a thin gradation image, in other words, a low density image is printed on the surface Sa. The inventors set the energization time relatively short when the density of the surface print image is high, and set the energization time relatively long when the density of the surface print image is low. The verification result that the dot print processing trace becomes inconspicuous was obtained.

  Based on such a verification result, the sublimation printer 1 of the present embodiment determines the gradation value of the surface print image that can regulate the density of the surface print image, the temperature of the thermal head 31, and the temperature of the sublimation printer 1 itself. By adopting a novel technical idea of correcting the dot print energization time from the data acquired with respect to the gradation value and temperature as a correction parameter, it is possible to suppress the occurrence of dot print processing traces on the surface Sa of the paper S. It became something that could be done. More specifically, when the tone value of the surface print image, the temperature of the thermal head 31 and the temperature of the sublimation printer 1 itself are high, that is, the density of the surface print image is high (dark), the dot print energizing time is set. When the tone value of the surface print image, the temperature of the thermal head 31 and the temperature of the sublimation printer 1 itself are low, that is, the density of the surface print image is low (thin), the dot print energization time is set to be relatively short. Correction is made to make it relatively long.

  On the other hand, the “second correction energization time determined based on the temperature” is a correction value of the energization time determined based on the temperature around the back surface printing unit 4 when performing the dot print processing. The correction energization time is determined based on the temperature of the dot print head 41 (specifically, the temperature of the dot pin 41a), the temperature of the sublimation printer 1 itself, and the temperature of the paper S. Normally, the temperature of the paper S is equal to or substantially equal to the temperature of the sublimation printer 1 itself. However, the sublimation printer 1 of the present embodiment has the front surface print unit 3 disposed upstream of the back surface print unit 4 and the paper. Since the dot printing process is performed on the back surface Sb of the paper S after the sublimation printing process is performed on the front surface Sa of the S, the temperature of the paper S changes before and after the sublimation printing process. Therefore, in this embodiment, since it is desired to grasp the temperature of the paper S at the time of dot printing processing or immediately before the dot printing processing, the “temperature of the paper S” used as the correction parameter is set to the time before the sublimation printing processing. The temperature of the sublimation printer 1 itself, which is equivalent to the temperature, and the temperature rise calculated from the amount of heat given to the paper S in the sublimation printing process, that is, the temperature rise calculated from the time during which a signal for causing the thermal head 31 to generate heat is given. And so on. Further, in the sublimation type printer 1 of the present embodiment, the temperature of the dot print head 41 and the temperature of the sublimation type printer 1 itself are set to be detected and acquired by a temperature detection unit such as a thermistor provided individually. ing.

  In the sublimation printer 1 according to the present embodiment, the dot print energizing time correction unit 444 in the back surface print control unit 44 uses the temperature of the dot print head 41, the temperature of the sublimation printer 1, and the temperature of the paper S as parameters. A table corresponding to or closest to the detected temperature of the dot print head 41, the temperature of the sublimation printer 1, and the temperature of the paper S is selected (selected) from a plurality of tables (not shown). Set the correction energization time. A plurality of tables using the temperature of the dot print head 41, the temperature of the sublimation printer 1 and the temperature of the paper S as parameters are stored in a predetermined recording device such as an internal memory or an external storage device in the sublimation printer 1, for example. Stored.

  Here, the reason why the present inventors have come up with the necessity of correcting the dot print energizing time based on the temperature around the back surface printing unit 4 during such dot print processing is as follows.

  That is, as a result of searching for the cause of the problem that the density of the back surface print due to the dot print process varies, the present inventors have found that various temperature conditions when performing the dot print process, in particular, the temperature conditions around the back surface print unit 4. I found that it had a big influence. Specifically, even when the energization time of the dot pin 41a, that is, the time for hitting the dot pin 41a against the back surface Sb of the paper S is the same, the density of the back surface print by the dot print process is high (dark) in a high temperature environment. It has been found that the density of the back side print by the dot print process is low (light) in the low temperature environment. Furthermore, the present inventors have found that the backside print density varies depending on the energization time of the dot pin 41a. Specifically, if the energization time of the dot pin 41a is long, the backside print density is high. It has also been found that the backside print density is low if the energization time of 41a is short. The inventors set the energization time relatively short during the dot print process or immediately before the dot print process to set the energization time relatively short, and immediately before the dot print process or just before the dot print process. When the temperature around the back surface printed portion 4 is low, a verification result has been obtained that it is difficult to cause variations in the density of the back surface print by setting the energization time relatively long.

  Based on such a verification result, the sublimation type printer 1 of the present embodiment is capable of considering the temperature of the dot print head 41 as a factor that can be regarded as the temperature around the back surface print unit 4 at the time of the dot print process or immediately before the dot print process. Back printing by dot print processing by adopting a novel technical idea of correcting the temperature of the sublimation printer 1 and the temperature of the paper S as correction parameters and correcting the dot print energization time from the data acquired for these temperatures. It was difficult for variations in the concentration of to occur. More specifically, when the temperature of the dot print head 41, the temperature of the sublimation printer 1, and the temperature of the paper S are high, that is, when the temperature around the back surface printing unit 4 is high at the time of the dot print process or immediately before the dot print process. The dot print energization time is relatively shortened, and the temperature of the dot print head 41, the temperature of the sublimation printer 1, and the temperature of the paper S are low, that is, the periphery of the back surface print unit 4 at the time of the dot print process or just before the dot print process. When the temperature is low, the dot print energization time is corrected to be relatively long.

  Further, the sublimation printer 1 according to the present embodiment uses the dot print energization time correction unit 444 to obtain the first correction energization time obtained by using the density of the surface print image as a correction parameter during the basic energization time described above, and the dot print. The time during which the dot pin 41a is pressed against the back surface Sb of the paper S is corrected by adding the second correction energization time obtained using the temperature around the back surface print unit 4 as a correction parameter at the time of processing or immediately before the dot print processing. Set as a certain dot print energizing time. The first correction energization time and the second correction energization time can be either a positive value or a negative value. The back surface print control unit 44 activates each dot pin 41a based on the dot print energization time set in this way, so that incidental information such as predetermined characters and symbols on the back surface Sb of the paper S varies in density. It is printed in a state where there is no or almost no state, and the occurrence of dot print processing marks on the surface Sa of the paper S can be suppressed.

  As described above, the sublimation printer 1 according to the present embodiment is a process in which the sheet transport mechanism 6 transports the sheet S from the sheet feeding unit 2 toward the sheet discharge unit 5. Sublimation printing processing is performed on Sa, and then dot printing processing is performed on the back surface Sb of the paper S by the back surface printing unit 4, and the roll-shaped paper S is cut by the cutter unit 7 at the same time or almost simultaneously with the dot printing processing. The sheet discharge roller 623 and the downstream second pinch roller 624 are set to discharge from the sheet discharge portion (sheet discharge port 5).

  As described above, in the sublimation printer 1 according to the present embodiment, the back surface print control unit 44 in the back surface print unit 4 has the density of the front surface print image and the temperature around the back surface print unit 4 at the time of the dot print process or immediately before the dot print process. A time obtained by correcting the basic energization time using the correction energization time (first correction energization time, second correction energization time) determined based on the dot print energization time is set as the dot print energization time. Since the energizing time of the dot pin 41a (specifically, the dot pin 41a) is controlled, the front surface Sa of the paper S is subjected to the sublimation printing process by the front surface printing unit 3, and the back surface of the paper S is back to the back surface Sb. Although the print unit 4 performs the dot print process, the dot printer process trace is formed on the surface Sa of the paper S. It is possible to suppress the raw, Further, it is possible to effectively prevent the variation in the concentration of the back surface printing taking the dot printing process due to the influence of temperature.

  In addition, this invention is not limited to embodiment mentioned above. For example, in the above-described embodiment, the first correction energization time determined based on the density of the image printed on the surface of the paper by the front surface print unit is the gradation value of the front surface print image, and the thermal head constituting the front surface print unit. The temperature is set based on the temperature of the sublimation printer and the temperature of the sublimation printer itself. However, the gradation value of the surface print image, the temperature of the thermal head constituting the surface print section, and the temperature of the sublimation printer itself are described. The first correction energization time may be set based only on at least one of the parameters.

  Further, in the aspect, the density itself of the image printed on the surface of the paper by the front surface printing unit is directly detected by an appropriate means, and the first correction energization time is set based on the detected density of the front surface printed image itself. Also good.

  Similarly, in the above-described embodiment, the second correction energization time determined based on the temperature around the back surface print unit at the time of the dot print process or immediately before the dot print process is the temperature of the dot print head, the temperature of the sublimation printer, and Although the mode set based on the temperature of the paper is illustrated, the second correction energization time is based on only the temperature of the dot print head, the temperature of the sublimation printer, and the temperature of the paper, and at least one of these three parameters. May be set.

  Further, the temperature itself around the back surface printed part at the time of the dot printing process or immediately before the dot printing process is directly detected by a temperature detecting part such as a thermistor, and the second correction energization time is set based on the detected temperature itself. May be.

  As a method for calculating the dot print energization time in the control unit (back surface print control unit), the embodiment described above exemplifies a method of calculating by adding the first correction energization time and the second correction energization time to the basic energization time. The dot print energization time may be determined by correcting the basic energization time using the first correction energization time and the second correction energization time by a method other than such addition. For example, a calculation method such as a method of multiplying the first correction energization time or the second correction energization time by a constant for weighting and adding to the basic energization time can be mentioned.

  Furthermore, in the above-described embodiment, the sublimation type printer that performs the sublimation printing process on the back surface of the paper by the back surface printing unit after performing the sublimation printing process on the front surface of the paper is exemplified. A sublimation type printer that performs a sublimation printing process on the front surface of a sheet of paper after a dot printing process is performed on the back surface of the paper by a front surface printing unit may be applied to the present invention. In this case, the first correction energization time is determined based on the density of the image printed on the surface of the paper by the front surface printing unit, and determines the density of the image printed on the front surface of the paper by the front surface printing unit. One factor “the gradation value of the front surface printed image” is the gradation value of the image printed on the surface of the paper by the front surface printer unit. On the other hand, when the paper temperature is used as a parameter for determining the second correction energization time, the temperature of the paper at the time of the dot printing process or immediately before the dot printing process is the temperature before being affected by heat by the sublimation printing process, that is, the temperature of the sublimation printer. It can be understood as temperature itself.

  In the above-described embodiment, an example in which the first correction energization time and the second correction energization time are determined by the table processing method is illustrated. However, the value of each correction parameter obtained is applied to a preset calculation formula. A function processing method for calculating the first correction energization time and the second correction energization time may be employed.

  Further, a single control unit that integrates the front side print control unit and the back side print control unit may be configured to control the sublimation print processing on the front side of the paper and the dot print processing on the back side of the paper.

  Further, in the above-described embodiment, the control unit performs sublimation in a mode in which the operation of the dot pin is controlled using the time when the basic energization time is corrected by the first correction energization time and the second correction energization time as the dot print energization time. However, it may be a sublimation type printer in which the control unit controls the operation of the dot pin using the time when the basic energization time is corrected only by the first correction energization time as the dot print energization time. If this is the case, the problem of "dot print processing traces on the surface of the paper" that is a problem peculiar to sublimation printers that perform front surface printing by sublimation printing processing and back surface printing by dot printing processing is solved. In addition, the surface print quality can be improved.

  Further, in the above-described embodiment, the mode in which only the dot pin moves in the direction in which the dot pin is in contact with or separated from the paper in the relationship between the dot pin and the paper is illustrated, but the present invention is not limited thereto, and the paper is in contact with the dot pin. It may be an aspect of moving in the direction of separation.

  Further, when applying the temperature of the sublimation printer itself (temperature in the sublimation printer) as a correction parameter for the dot print energization time, members that can be in direct contact with the paper, for example, various members that constitute the paper transport mechanism in the above-described embodiment ( The temperature of the sublimation printer (the temperature in the sublimation printer) may be obtained by detecting the temperature of the paper feed roller 611 and the like.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Sublimation type printer 3 ... Front surface print part 31 ... Thermal head 4 ... Back surface print part 41 ... Dot print head 41a ... Dot pin 44 ... Control part (back surface print control part)
S ... paper

Claims (7)

A sublimation type printer provided with a surface print section for performing a sublimation print process on the surface by pressing an ink ribbon against the surface of the paper with a thermal head and heating it,
A dot print head having a plurality of dot pins, and a control unit that controls a dot print energization time that is a time for pressing the dot pins against the back surface of the paper; Further comprising a back side print unit that performs dot printing on the back side by pressing against the back side of
The controller prints the basic energization time, which is the energization time to be ensured in order to establish the dot print processing by the back surface print unit, on the image printed on the paper surface or the paper surface by the front surface print unit. The correction is performed by a first correction energization time determined based on the density of the surface print image which is a printed image, and the operation of the dot pin is controlled using the corrected time as the dot print energization time. Sublimation printer. The control unit determines the basic energization time as the first correction energization time and the second correction energization determined based on the temperature around the back surface print unit at the time of the dot print process by the back surface print unit or immediately before the dot print process. 2. The sublimation type printer according to claim 1, wherein the operation of the dot pin is controlled by using the corrected time as the dot print energizing time. 2. The sublimation printer according to claim 1, wherein the control unit controls the operation of the dot pin using the dot print energization time as a time corrected by adding the first correction energization time to the basic energization time. . The control section controls the operation of the dot pin using the time corrected by adding the first correction energization time and the second correction energization time to the basic energization time as the dot print energization time. 2. A sublimation printer according to 2. The first correction energization time is determined based on the gradation value of the front surface print image, which is a factor that determines the density of the front surface print image, the temperature of the thermal head of the front surface print unit, or the temperature of the sublimation printer itself. The sublimation printer according to any one of claims 1 to 4. The second correction energization time is a factor for determining the temperature around the back surface print unit at the time of the dot print process by the back surface print unit or immediately before the dot print process, the temperature of the dot print head, the temperature of the sublimation printer itself, The sublimation printer according to claim 2 or 4, wherein the sublimation printer is determined based on a temperature of the paper. After performing the sublimation printing process by the front surface printing unit, the dot printing process by the back surface printing unit is performed,
The sublimation printer according to claim 6, wherein the temperature of the paper is determined based on a temperature of the paper before the sublimation printing process and a heat amount given to the paper by the sublimation printing process.

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