JP5720223B2 - Thermal printer - Google Patents

Description

  The present invention relates to a thermal printer that prints on a recording medium by heating control of a thermal head.

  As exemplified in Patent Document 1, for example, a thermal printer conveys a recording medium while sandwiching a recording medium such as paper between a conveying roller having a microprojection on a surface and a pinch roller, and performs thermal printing according to a print command. This is a printing apparatus that prints by transferring a transfer material such as ribbon ink or laminate onto a recording medium by controlling the heating of the head. In thermal printers, the greater the amount of heat of the thermal head, the greater the amount of transfer of the transferred material to the recording medium, and the higher the apparent density, and the smaller the amount of heat of the head, the less transferred the amount of transferred material to the recording medium. Utilizing the fact that the density is reduced, the print content related to the print command is expressed by the print gradation for each dot, and the desired printing is performed by controlling the heating of the thermal head so that the amount of heat corresponding to the print gradation is obtained. Is to do.

JP 2000-15886 A

  However, in the above-described conventional thermal printer, printing is performed with the same print gradation (heat amount) in both the grip area sandwiched by the portion of the recording roller where the micro protrusions are provided and the non-grip area that is not sandwiched. As a result, the grip area is printed lighter than the non-grip area even though printing is performed with the same print gradation. In this case, the print result in the grip region is shifted from the desired print result, and the print quality is impaired. In addition, the grip area becomes conspicuous even in relation to the non-grip area due to the printing result deviation of the grip area, and the print quality of the entire recording medium is also impaired. This problem is caused by pinching at a portion of the transport roller where there is a minute protrusion, forming a protrusion mark, also called a grip mark, in the grip area. This is considered to be caused by a decrease in the apparent density without adhering to the marks.

  The present invention has been made paying attention to such a problem. The object of the present invention is to convey a recording medium by a conveyance roller having minute protrusions, and to a grip region sandwiched by the conveyance roller. It is to provide a thermal printer with improved print quality when printing.

  In order to achieve this object, the present invention takes the following measures.

That is, the thermal printer of the present invention conveys the recording medium while sandwiching the recording medium by a conveying roller having a minute protrusion at one part of the surface, and includes a plurality of heating resistors arranged in the axial direction of the conveying roller. sandwiched site in grip region sandwiched by the site of microprojections of the conveying rollers of the transcript recording medium of the ribbon with the microprotrusions of the conveying roller by the heating control in response to a print command to a thermal head having A thermal printer that transfers heat to a non-grip area that has not been subjected to heat, which is related to the amount of heat that is associated in advance according to the printing gradation so as to obtain a desired printing result on the condition that heat transfer is performed to the non-grip area. The thermal data corresponding to the print gradation according to the print command is acquired from the data, and the heat amount corresponding to the thermal data is obtained. A heating control unit that controls the heating of the thermal head, and a correction unit that corrects thermal data corresponding to the print gradation according to the print command in a direction in which the amount of heat increases, and the grip area and the non-grip area for the thermal head acquiring position information of the amount of heat the heating control unit, for at least a portion of the heating resistor opposed to the grip region according to the location information, corresponding to the thermal data corrected by the pre-Symbol corrector while the thermal transfer pulsed current so that the amount of heat corresponding to the heat data not corrected for at least a portion of the heating resistor, the front Symbol corrector that faces the non-gripping area according to the location information Thus, the thermal transfer is performed by applying a pulse current .

Thus, for at least a portion of the heating resistor thermal data corresponding to the printing gradation according to the print command is corrected by the correction section in the direction of increasing the amount of heat, opposite to the grip region according to the position information Te, as well as thermal transfer pulsed current so that a corresponding amount of heat to the heat data after correction, to at least a portion of the heating resistor opposed to the non-gripping area according to the location information, the auxiliary Tadashibu Since heat transfer is performed by applying a pulse so that the amount of heat corresponds to the uncorrected heat data, the heat amount when heat transfer is performed with uncorrected heat data in at least a part of the non-grip area even with the same print gradation. Heat transfer to at least a part of the grip area with an amount of heat increased compared to the print area, increasing the transfer amount of the transferred material to this grip area to increase the density, and printing results in the grip area It is possible to improve print quality in the grip region close to the desired printing result. In addition, since the shift of the print result in the grip area is reduced or eliminated, the grip area becomes less noticeable or less noticeable than the non-grip area, and the print quality of the entire recording medium can be improved.

  In order to avoid the print quality from being impaired by the correction, the correction unit gradually increases the correction value of the heat amount along the direction orthogonal to the recording medium conveyance direction in the vicinity of the boundary between the non-grip area and the grip area. It is preferable to increase it.

To improve print quality by increasing the correction accuracy by avoiding insufficient excessive correction and correction, the correction unit, the unit gray level of the printing gradation in thermal data about the amount of heat that is pre-associated with each indicia Surikaicho It is desirable to perform correction using a correction value having a magnitude corresponding to the amount of change in heat per difference.

  In order to reduce problems caused by misalignment of the recording medium, the correction unit performs the correction in an area narrower than a width dimension along a direction perpendicular to the conveyance direction of the recording medium in the grip area. It is effective.

  In order to realize an accurate correction corresponding to the positional deviation of the recording medium, a position sensor for detecting the position of the recording medium is provided, and the position between the position sensor and a portion of the conveying roller where the minute protrusion is provided is provided. The relationship and the positional relationship between the position sensor and the thermal head are set in advance, and after the first surface of either side of the recording medium is sandwiched and transported by the transport roller, it is transported once. When the recording medium is separated from the roller, and then printing is performed on the first surface while the back surface of the first surface of the recording medium is nipped and conveyed by the conveyance roller, the conveyance roller is The position information of the grip area and the non-grip area on the first surface is acquired based on the detection result of the position sensor when holding the grip, and the acquired position information and the conveyance roller sandwich the back surface of the first surface. It is preferably configured to acquire location information of the grip region and the non-gripping regions of the first surface with respect to the thermal head on the basis of the detection result of the position sensor when you are.

  Since the present invention has the above-described configuration, the grip is performed with an amount of heat increased as compared with the amount of heat when heat transfer is performed with heat data that is not corrected in at least a part of the non-grip region even with the same print gradation. Heat transfer to at least a part of the area, increase the transfer amount of the transferred material to the grip area to increase the density, and bring the print result in the grip area closer to the desired print result to improve the print quality in the grip area Is possible. In addition, since the shift of the print result in the grip area is reduced or eliminated, the grip area becomes less noticeable or less noticeable than the non-grip area, and the print quality of the entire recording medium can be improved. Therefore, it is possible to provide a thermal printer with improved printing quality.

1 is a diagram schematically showing an overall configuration of a thermal printer according to an embodiment of the present invention. The figure which shows typically the heating control part of the thermal printer, and the structure relevant to it. Explanatory drawing regarding the operation | movement of double-sided printing in the thermal printer. Explanatory drawing regarding the operation | movement of double-sided printing in the thermal printer. Explanatory drawing regarding the operation | movement of double-sided printing in the thermal printer. The figure which shows typically the heat information and correction information which are preset to the thermal printer. The comparison figure which shows typically the thermal printer of this embodiment about the amount of heat and the printing result by it, and this embodiment. The figure which shows typically the correction value which concerns on other embodiment of this invention.

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

  As shown in FIG. 1, the thermal printer is configured to thermally transfer a paper feeding unit 1 that holds a recording medium Pa such as a rolled roll paper and a ribbon Rb coated with ink or a laminate layer to the recording medium Pa by thermal transfer. A plurality of printing units 2 and 3 that perform printing, a main path Li0 that transports the recording medium Pa supplied from the paper supply unit 1, and a main path Li0 that is connected to the main path Li0 via a branching unit 53. Branch paths Li1 and Li2 that communicate with the printing sections 2 and 3, a transport roller section 5 that transports the recording medium Pa on the branch paths Li1 and Li2, and transport control and printing sections 2 and 3 of the recording medium Pa. And a control unit 6 that performs printing control of the recording medium Pa. The recording medium Pa held in the paper feeding unit 1 through the conveyance roller unit 5 is sequentially conveyed to the printing units 2 and 3 to perform double-sided printing on the recording medium Pa. is there.

  As shown in FIG. 1, the paper feeding unit 1 rotatably holds a recording medium Pa wound in a roll shape, and the recording medium Pa is centered on a roll axis C <b> 1 by a power unit such as a motor (not shown). The recording medium Pa is configured to be able to perform forward and reverse rotations so that the recording medium Pa can be fed out and rewound, and is supplied toward the printing units 2 and 3 while holding the recording medium Pa between the pair of feed rollers 12 and 12. To do.

  The branching unit 53 serves as a switching unit that switches the transport destination of the recording medium Pa on the trunk path Li0 to either the branching path Li1 or the branching path Li2. The switching is controlled by the control unit 6.

  The conveyance roller unit 5 is disposed inside both the branch paths Li1 and Li2, and includes a conveyance roller 51 called a metal microgrip roller that obtains a driving force for conveying the recording medium Pa from a power unit such as a motor (not shown). The roller 51 has pinch rollers 52 and 52 that sandwich the recording medium Pa in the branch path Li1 and the branch path Li2, respectively, and the conveyance roller 51 is rotated in a state where the recording medium Pa is sandwiched between the rollers 51 and 52. To transport the recording medium Pa. As shown in FIG. 2, the transport roller 51 extends over the entire surface in the circumferential direction at a position that sandwiches two positions on both ends of the recording medium Pa in the width direction (main scanning direction) orthogonal to the transport direction of the recording medium Pa. Thus, a minute protrusion t is formed, and the minute protrusion t increases the frictional force with the recording medium Pa, thereby enabling highly accurate conveyance. In this specification, as shown in FIG. 2, the recording medium Pa sandwiched by the conveyance roller 51 having the minute protrusions is defined as a grip area. The area that is not sandwiched by the portion where the minute protrusion t of the transport roller 51 is located is referred to as Ar1 and is referred to as a non-grip area Ar2. A projection mark is formed on the surface of the grip region Ar1 by the minute projection t.

As shown in FIG. 1, the printing unit 2 uses a ribbon Rb in which a transfer material such as ink is applied to a recording medium Pa supplied from the paper feeding unit 1 via the trunk path Li0 and the branch path Li1. Then, the transfer product of the ribbon Rb is thermally transferred (printed). The printing unit 3 has substantially the same configuration as the printing unit 2, and performs thermal transfer (printing) on the recording medium Pa supplied from the paper feeding unit 1 via the trunk path Li0 and the branch path Li2. On the ribbon Rb, a transfer product of yellow, magenta, cyan, and overcoat layer is applied in order along the ribbon feeding direction. As shown in FIG. 1, the printing units 2 and 3 have a thermal head 21 in which a plurality of heating resistors 21 a that generate heat when energized are arranged so as to form one line along the axial direction of the transport roller 5. (Refer to FIG. 2), a platen roller 22 facing the thermal head 21, and a ribbon transport unit 23 that feeds the ribbon Rb to the thermal head 21 and forms a pair for winding the ribbon Rb reaching the thermal head 21. The thermal head 21 and the platen roller 22 are configured to be relatively close to and away from each other.

  As shown in FIG. 2, a plurality of heating resistors 21a are arranged corresponding to each pixel (dot) constituting one line, and a transfer material such as ink on the ribbon Rb or a laminate layer is transferred to the recording medium Pa by heat generated by energization. The corresponding pixel is printed by transferring to the pixel, and the recording medium Pa is moved in the printing direction which is one of the sub-scanning directions to supply the pixels in the main scanning direction in line units. The pixels are printed in order along the printing direction while printing.

  1 and 2, for example, as shown in FIG. 3, the control unit 6 supplies the recording medium Pa from the paper feeding unit 1 to the printing unit 2 by sandwiching the conveyance roller unit 5, and the printing unit 2 uses the recording medium 2. When printing is performed on a certain surface f of Pa and printing in the printing unit 2 is completed, the recording medium Pa is wound around the paper feeding unit 1 as shown in FIG. 5, and then, as shown in FIG. 5, the conveyance destination by the branching unit 53 is switched, the recording medium Pa is fed out again to the conveyance roller unit 5, and the recording medium Pa is sandwiched by the conveyance roller unit 5, and the printing unit A series of operations and other requirements necessary for double-sided printing in which the recording medium Pa is supplied to the sheet 3 by the conveyance roller unit 5 and the printing unit 3 performs printing on the back surface b of the certain surface f of the recording medium Pa. In order to perform the above operations, the driving of the respective units 1 to 5 is controlled. The control unit 6 is configured by a normal microcomputer unit having a CPU, a memory, and an interface as in a known thermal printer, and a necessary program such as a print control processing routine (not shown) is written in the memory. As shown in FIG. 2, the CPU calls and executes necessary programs as appropriate to cooperate with the peripheral hardware resources, and to the heat generating resistor 21a so as to obtain a heat amount corresponding to the print gradation related to the print command. The heating control unit 61 that controls the heating of the thermal head 21 is realized by controlling the energization.

  As shown in FIG. 2, the heating control unit 61 stores, in a memory, heat data relating to the amount of heat with which a desired print result can be obtained on the condition that a transfer is performed on the non-grip area Ar2 in advance for each print gradation. The thermal data 62, the thermal data acquisition unit 63 that acquires thermal data corresponding to the print gradation according to the print command based on the thermal information 62, and pulses the heating resistor 21a so as to obtain a heat quantity corresponding to the thermal data. And an energization section 64 for energizing. The amount of heat and heat data here correspond to the amount of energization (number of pulses) energized to the heating resistor 21a and are also referred to as energization amount and energization data.

In the present embodiment, as shown in FIG. 6, the heat information 62 is information that associates heat data related to the amount of heat (number of energized pulses) for each print gradation so that appropriate color expression (desired print result) can be obtained. As a result, the amount of heat (number of energized pulses) does not change linearly according to the printing gradation, but the amount of change Δ (slope) of the amount of heat per unit gradation difference of the printing gradation is Δ _{1 in the} figure. And Δ ₂ are set so as to change depending on the print gradation.

  In the present embodiment, the following configuration is further added to the above configuration. That is, as shown in FIG. 1, the branch paths Li1 and Li2 between the conveying roller unit 5 and the thermal head 21 are provided with light-shielding type position sensors 7 and 7 for detecting the position of the recording medium Pa, respectively. . As shown in FIG. 2, these position sensors 7 are set in advance in relation to the positional relationship with the portion of the transport roller 51 where the minute protrusions t are provided, and are connected to the heating resistor 21 a of the thermal head 21. Are set in advance in association with each other. Specifically, the position sensor 7 detects the relative position of the side edge eg in the main scanning direction (width direction) of the recording medium Pa with the reference position X0 set in advance as a base point. As a specific example, in the example shown in FIG. 2, the reference position X0 is set to X coordinate value 0 with the main scanning direction as the X coordinate axis, and the position sensor 7 has the width direction side edge eg of the recording medium Pa as X coordinate value X1. To detect. In addition, the portion of the transport roller 51 where the minute protrusion t is provided is set to have a coordinate value X2 to an X coordinate value X3 with the reference position X0 as a base point. Further, the heating resistor 21a of the thermal head 21 is set in association with the X coordinate having the reference position X0 as a base point.

  Further, as shown in FIG. 2, the control unit 6 obtains position information of the grip area Ar1 and the non-grip area Ar2 with respect to the thermal head 21 (heating resistor 21a) based on the detection result of the position sensor 7. An acquisition unit 65 is provided. The position information acquisition unit 65 is configured to be able to acquire position information of the grip area Ar1 and the non-grip area Ar2 in the recording medium Pa based on the preset positional relationship and the detection result of the position sensor 7. Based on the positional information of the grip area Ar1 and non-grip area Ar2 in the acquired recording medium Pa, the preset positional relationship and the detection result of the position sensor 7, the grip area Ar1 and the non-grip with respect to the thermal head 21 (heating resistor 21a). The position information of the grip area Ar2 can be acquired. Specifically, as shown in FIG. 2, when the position sensor 7 detects that the position of the side edge eg of the recording medium Pa is X1 (X0 is zero), the position of the grip area Ar1 in the recording medium Pa is Obtained from the X coordinate value (X2-X1) to the X coordinate value (X3-X1) starting from one side edge eg of the recording medium Pa in the width direction, and the other area is the non-grip area Ar2. And get. Under this specification, when the recording medium Pa is displaced in the width direction and the position sensor 7 detects that the position of the side edge eg of the recording medium Pa is X1 ′ (X0 is zero), the grip area Ar1 for the thermal head 21 is detected. Is acquired from the X coordinate (X2−X1 + X1 ′) to the X coordinate (X3−X1 + X1 ′) with the reference position X0 as a base point, and is acquired when the other region is the non-grip region Ar2.

Further, as shown in FIG. 2, the control unit 6 is provided with a correction unit 66 that corrects the heat data corresponding to the print gradation related to the print command in the direction in which the amount of heat increases. Then, the control unit 6 refers to the position information of the grip area Ar1 and the non-grip area Ar2 acquired by the position information acquisition unit 65, and transfers the transfer product of color inks such as yellow, magenta, and cyan at least part of the grip area Ar1. per to do thermal transfer with respect to a pulse current to the heating resistor 21a which conducting portion 64 so as to heat corresponding to the heat data corrected by the correction unit 66 is opposed to at least a portion of said grip region Ar1 to together, carrying out a thermal transfer with respect to transcripts of the color inks at least a portion of the non-gripping regions Ar @ 2, the correction unit conducting portion 64 so as to heat corresponding to the heat data not corrected by 66 the non It is configured to pulse current to the heating resistor 21a which faces at least a portion of the grip region Ar2 That.

  As shown in FIG. 2, the correction value of the heat amount in the grip area Ar1 by the correction unit 66 is stored in advance as correction information 66a in association with each print gradation, and as schematically shown in FIG. As the information 62, a correction value having a magnitude corresponding to the amount of change Δ (slope) of the amount of heat per unit gradation difference of the print gradation is set in the heat data relating to the amount of heat associated beforehand according to the print gradation. That is, the correction value is set to increase as the change amount Δ of the heat amount per unit gradation difference of the printing gradation increases (that is, as the inclination becomes steeper), and conversely, The correction value is set to be smaller as the change amount Δ of the heat amount is smaller (that is, the gradient is gentler). This is because when the same correction value is used regardless of the amount of heat change Δ per unit gradation difference, correction is insufficient for printing gradations with a large amount of heat change Δ, while printing with a small amount of heat change Δ is small. This is because the tone is overcorrected, and the correction accuracy is improved by avoiding overcorrection and insufficient correction.

  Further, as shown in FIG. 7B, the correction unit 66 shown in FIG. 2 has a width direction (main scanning direction) orthogonal to the conveyance direction of the recording medium Pa in the vicinity of the boundary between the non-grip area Ar2 and the grip area Ar1. The heat amount correction value is gradually changed along Specifically, as shown in FIG. 7B, the correction value of the heat amount is gradually increased from the non-grip region Ar2 toward the grip region Ar1. This avoids an abrupt change in heat and prevents the sudden change in heat from being recognized as a boundary by the viewer. In the present embodiment, the grip area Ar1 is corrected as the distance from the grip area Ar1 is increased on both sides in the width direction with respect to the correction value of the grip area Ar1 expressed in a rectangular shape along the width direction (main scanning direction) of the recording medium Pa. A relaxation part as (annealing part) that gradually becomes the correction value 0 from the size of about a quarter of the value H2 is provided. In other words, in this annealed portion, the correction value of the heat amount is gradually decreased from the grip area Ar1 toward the non-grip area Ar2 along the width direction (main scanning direction). As shown in FIG. 7B, the relaxation part as (annealing part) may be provided in the non-grip area Ar2 as long as it does not appear in the printing result. The grip area Ar1 and the non-grip area You may provide over both area | regions Ar1 and Ar2 of Ar2. In other words, the correction unit 66 may correct the heat transfer to the non-grip area Ar2.

  The operation of the thermal printer having the above configuration will be described. As shown in FIG. 3, the recording medium Pa is supplied from the paper feeding unit 1 to the printing unit 2, and either one of the first surfaces b of both sides of the recording medium Pa is provided. Is printed on the back surface f of the first surface b while being nipped by the transport roller 51 and transported. In this case, the position information of the grip area Ar1 and the non-grip area Ar2 on the first surface b is acquired based on the detection result of the position sensor 7 when the transport roller 51 holds the first surface b.

  When the printing in the printing unit 2 is completed, as shown in FIG. 4, the recording medium Pa is wound around the paper feeding unit 1, and the recording medium Pa is once separated from the conveying roller 51, and thereafter, as shown in FIG. The recording medium Pa is again fed out to the printing unit 3 through the conveyance roller unit 5, and the conveyance roller clamps the back surface f of the first surface b. In this case, based on the already acquired position information of the grip area Ar1 and the non-grip area Ar2 in the recording medium Pa and the detection result of the position sensor 7 when the transport roller 51 holds the back surface f of the first surface b. The position information of the grip area Ar1 and the non-grip area Ar2 of the first surface b with respect to the heating resistor 21a of the thermal head 21 is acquired.

And when printing on the 1st surface b, as shown in FIG. 2, the thermal data acquisition part 63 is the thermal data (heat amount H1) corresponding to the printing gradation P which concerns on a printing command for every heating resistor 21a. ) Based on the heat information 62. Here, for simplification of description, it is assumed that the print gradations of all the heating resistors (all print regions including the grip region Ar1 and the non-grip region Ar2) are the same. When printing is performed with the heat quantity H1 corresponding to the thermal data acquired by the thermal data acquisition unit 63, the same print gradation (see FIG. 7A), as schematically showing the apparent density recognized by the viewer. Despite the heat quantity H1), the apparent density of the grip area Ar1 is lower than the apparent density N1 (desired printing result) of the non-grip area Ar2. Therefore, the relative grip region Ar1, as schematically shown in FIG. 7 (b), the correction unit 66, using the correction value H2 etc. of heat according to the print tone P stored as correction information 66a Then, the heat data is corrected in the direction of increasing the heat amount, and thermal transfer is performed with the heat amount (H1 + H2) corresponding to the corrected heat data. Also, for some of the non-gripping regions Ar @ 2, as schematically shown in FIG. 7 (b), performs thermal transfer in heat (H1) corresponding to the heat data not corrected by the correction unit 66, the non and to other regions of the grip region, as schematically shown in FIG. 7 (b), performing the transfer by the heat data after corrected corrected as relaxation sites as (smoothing site) by the correction unit 66. Then, as schematically shown in the figure, the transfer amount of the transferred material to the grip area Ar1 increases, the visual density recognized by the viewer increases, and the print result in the grip area Ar1 is brought closer to the desired print result. Is possible.

  As described above, the thermal printer according to the present embodiment transports the recording medium Pa while sandwiching the recording medium Pa by the transport roller 51 having the minute protrusions t at one part of the surface, and the thermal head according to the print command. 21, the transfer product of the ribbon Rb is sandwiched between the grip region Ar <b> 1 sandwiched by the portion with the minute protrusion t of the transport roller 51 and the portion with the minute protrusion t of the transport roller 51. Thermal printer that performs thermal transfer to a non-grip region Ar2 that is not associated with the print data, and that is associated with the amount of heat in advance in accordance with the print gradation so as to obtain a desired print result on the condition that thermal transfer is performed to the non-grip region Ar2. Heat data corresponding to the print gradation P related to the print command is acquired, and the heat amount H1 corresponding to this heat data is obtained. A heating control unit 61 that controls the heating of the thermal head 21 is provided, and a correction unit 66 that corrects the heat data (heat amount H1) corresponding to the print gradation P related to the print command in the direction of increasing the heat amount is provided. When the position information of the grip area Ar1 and the non-grip area Ar2 is acquired and thermally transferred to at least a part of the grip area Ar1 related to the position information, the heating control is performed by the heat data (heat quantity H1 + H2) corrected by the correction unit 66. When the part 61 performs thermal transfer, and when performing thermal transfer on at least a part of the non-grip area Ar2 related to the position information, the heating control unit 61 performs thermal transfer using thermal data (heat amount H1) that is not corrected by the correction unit 66. I am doing so.

  As described above, when heat transfer is performed on at least a part of the grip area Ar1, the correction unit 66 corrects the heat data (heat amount is H1) corresponding to the print gradation P related to the print command in the direction in which the heat amount increases. When heat transfer is performed with the corrected heat data (heat amount is H1 + H2), and heat transfer is performed with respect to at least a part of the non-grip area Ar2, heat transfer is performed with heat data (heat amount H1) not corrected by the correction unit 66. Even at the same print gradation, at least a part of the grip area Ar1 with the amount of heat (H1 + H2) increased compared to the amount of heat H1 when heat transfer is performed with the heat data not corrected in at least a part of the non-grip area Ar2. Heat transfer to the grip area Ar1, increase the transfer amount of the transferred material to the grip area Ar1 to increase the density, and print the print result in the grip area Ar1 as desired. It is possible to improve print quality in the grip region Ar1 close to the result. In addition, since the printing result deviation in the grip area Ar1 is reduced or eliminated, the grip area Ar1 is less noticeable or less noticeable than the non-grip area Ar2, and the print quality of the entire recording medium can be improved.

  In particular, there is a portion where the amount of heat changes suddenly due to the correction and the printing result changes rapidly, and this portion is recognized by the viewer. The unit 66 gradually increases the correction value of the heat amount from the non-grip area Ar2 toward the grip area Ar1 in a direction orthogonal to the conveyance direction of the recording medium Pa in the vicinity of the boundary between the non-grip area Ar2 and the grip area Ar1. Therefore, it is possible to suppress a sudden change in the amount of heat due to the correction and to prevent the print quality from being impaired by the correction.

  Further, in the present embodiment, when the correction unit 66 performs thermal transfer to at least a part of the grip area Ar1, the heat amount per unit gradation difference of the print gradation in the heat data related to the heat amount associated in advance for each print gradation. Since the correction is performed using the correction value having a magnitude corresponding to the change amount Δ, it is possible to avoid overcorrection and insufficient correction, improve the correction accuracy, and improve the print quality.

  In addition, in this embodiment, the position sensor 7 for detecting the position of the recording medium Pa is provided, the positional relationship between the position sensor 7 and the portion of the transport roller 51 where the minute protrusion t is provided, and the position sensor 7 and the thermal sensor. The positional relationship with the head 21 is set in advance in association with each other, and after the first surface b of either side of the recording medium Pa is sandwiched and transported by the transport roller 51, recording is once performed from the transport roller 51. When the medium Pa is separated and then printing is performed on the first surface b while the back surface f of the first surface b of the recording medium Pa is nipped and transported by the transport roller 51, the transport roller 51 Based on the detection result of the position sensor 7 when the first surface b is sandwiched, the position information of the grip region Ar1 and the non-grip region Ar2 on the first surface b is acquired, and the acquired position information and Position information of the grip area Ar1 and the non-grip area Ar2 of the first surface b with respect to the thermal head 21 based on the detection result of the position sensor 7 when the transport roller 51 holds the back surface f of the first surface b. Since the positional information of the grip area Ar1 and the non-grip area Ar2 with respect to the thermal head 21 can be acquired even when the recording medium Pa is separated from the conveyance roller 51, the recording medium Pa is conveyed. Accurate correction can be performed in accordance with the positional deviation of the recording medium Pa that may occur when the roller 51 is separated from the roller 51.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not only by the above description of the embodiments but also by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the present embodiment, correction is performed on the thermal data relating to the area matched to the width dimension of the grip area Ar1 in the direction (width direction) orthogonal to the conveyance direction of the recording medium Pa. FIG. And as shown in FIG.8 (b), you may make it correct | amend in the area | region where width w2 is narrower than the width dimension w1 of grip area | region Ar1 (w1> w2). If correction is performed on the thermal data related to the grip area, if the position of the recording medium Pa is shifted in the width direction, printing is performed with an excessive amount of heat for a part of the non-grip area Ar2. However, in the case of the present invention, the thermal data related to the region w2 narrower than the width dimension w1 of the grip region Ar1 is corrected. First, even when the position of the recording medium Pa is shifted in the width direction, the shift can be absorbed by the grip area Ar1, and problems due to the position shift can be reduced.

  Further, in this embodiment, the relaxation site as (smoothing site) is provided for the correction value. However, this can be omitted, and the mode of change of the relaxation site as is a linear change. The present invention is not limited to this, and various other forms such as a curved shape, a wave shape, and a step shape can be adopted. In this embodiment, the correction unit 66 performs correction to increase the amount of heat with respect to the thermal data corresponding to the print gradation related to the print command. However, the correction unit 66 performs heat correction corresponding to the print gradation related to the print command. Correction for increasing or decreasing the amount of heat with respect to the data may be performed, and the correction unit may be configured such that the correction value of the heat amount of the grip region is relatively increased with respect to the non-grip region.

  In this embodiment, when transferring a color ink transfer material such as yellow, magenta, and cyan, the grip area Ar1 is made inconspicuous by increasing the density of the grip area Ar1 higher than the density of the non-grip area Ar2. Another means for making the grip region Ar1 inconspicuous is to make the amount of heat in the grip region Ar1 different from the amount of heat in the non-grip region Ar2 when the overcoat layer, which is a transparent protective layer, is thermally transferred. Specifically, in the non-grip area Ar2, the amount of heat is kept substantially constant and glossy is printed with gloss, while in the grip area Ar1, the amount of heat is changed randomly or with a specific pattern to give a gradation difference. For example, performing mat printing. In this case, the overcoat layer in the grip area Ar1 becomes rough due to the gradation difference (transfer amount difference) due to mat printing, and the print result deviation in the grip area Ar1 may be made inconspicuous. Furthermore, the printing result deviation of the grip area Ar1 can be made inconspicuous by performing mat printing in which the amount of heat is changed randomly or in a specific pattern over the entire print area including the grip area Ar1 and the non-grip area Ar2. There is.

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

21 ... thermal head 51 ... transport roller 61 ... heating control unit 7 ... position sensor Ar1 ... grip area Ar2 ... non-grip area b ... first surface f ... back surface t of the first surface ... minute projection Pa ... recording medium Rb ... Ribbon P ... Print gradation H1 ... Heat amount corresponding to thermal data? ... Change amount of heat per unit gradation difference of print gradation w1 ... Width dimension of grip region

Claims (5)

In response to a print command, a thermal head having a plurality of heating resistors arranged in the axial direction of the transport roller is transported while the recording medium is sandwiched by a transport roller having a microprojection at a portion of the surface. By controlling the heating, the transfer of the ribbon is thermally transferred to a grip area of the recording medium that is sandwiched between the portions having the minute protrusions of the conveying roller and a non-grip region that is not sandwiched between the portions having the minute protrusions of the conveying roller. A thermal printer that
Thermal data corresponding to the print gradation related to the print command out of thermal data relating to the heat quantity associated in advance according to the print gradation so as to obtain a desired print result on the condition that the non-grip area is thermally transferred. And a heating control unit that controls the heating of the thermal head so that the amount of heat corresponding to the heat data is obtained, and the heat data corresponding to the print gradation according to the print command is corrected in the direction of increasing the amount of heat. Provide a correction unit,
Acquiring position information of the grip region and the non-gripping regions against the thermal head, the heating control unit, for at least a portion of the heating resistor opposed to the grip region according to the position information, pre-Symbol corrector and pulse current such that the corresponding amount of heat to the thermal data corrected by the addition to thermal transfer, to at least a portion of the heating resistor opposed to the non-gripping area according to the location information, the pre-Symbol corrector A thermal printer characterized in that heat transfer is performed by applying a pulse so that the amount of heat corresponds to uncorrected heat data.   2. The thermal printer according to claim 1, wherein the correction unit gradually increases a correction value of the heat amount along a direction orthogonal to the recording medium conveyance direction in the vicinity of the boundary between the non-grip region and the grip region. The correction unit according to claim for performing correction using the magnitude of the correction value in accordance with the change amount of heat quantity per unit gray level difference of the printing gradation in thermal data about the amount of heat that is pre-associated with each indicia Surikaicho The thermal printer according to 1 or 2.   The thermal printer according to claim 1, wherein the correction unit performs the correction in an area narrower than a width dimension along a direction orthogonal to a conveyance direction of the recording medium in the grip area. In addition to providing a position sensor for detecting the position of the recording medium, the positional relationship between the position sensor and the portion of the transport roller where the minute protrusion is provided, and the positional relationship between the position sensor and the thermal head are set in association with each other. Leave
After one of the two surfaces of the recording medium is nipped by the conveying roller and conveyed, the recording medium is once separated from the conveying roller, and then the back surface of the first surface of the recording medium is the conveying roller. When printing is performed on the first surface while being nipped and conveyed, the grip region on the first surface based on the detection result of the position sensor when the conveyance roller is nipping the first surface, and The position information of the non-grip area is acquired, and the grip of the first surface with respect to the thermal head is acquired based on the acquired position information and the detection result of the position sensor when the transport roller is holding the back surface of the first surface. The thermal printer according to any one of claims 1 to 4, wherein the thermal printer is configured to acquire position information of a region and a non-grip region.

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