JP2007038412A - Thermal transfer printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer printer which prevents a printing density from differing for every color at both faces. <P>SOLUTION: The thermal transfer printer is configured to carry out printing by thermally transferring ink (Y, M, C, K and L) of each ink region in an ink ribbon (9) equipped with the ink regions corresponding respectively to the ink (Y, M, C, K and L) of a plurality of colors one by one to predetermined faces of a member (1) to be printed. The predetermined faces are one surface (1a) and its opposite surface (1b) of the member to be printed. The thermal transfer printer has both a thermal head (8d) which carries out printing to the opposite surface (1b) after printing to the one surface (1a) and heats the ink regions, and a control part (20) which controls an amount of heat energy applied to the thermal head (8d). The control part (20) controls on the basis of the amount (Vcor) of heat energy applied to the thermal head (8d) in printing to the one surface (1a), the heat energy applied to the thermal head (8d) in printing to the opposite surface for every thermal transfer action for each of a plurality of the colors of the ink (Y, M, C, K and L). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal transfer printing apparatus, and more particularly, to a thermal transfer printing apparatus that performs printing on both sides of a substrate.

A so-called thermal transfer printing apparatus is known that heats a thermal head and prints ink on an ink ribbon on a substrate by a thermal transfer method.
Examples of the substrate include a resin card and paper.
The thermal transfer method uses, for example, an ink ribbon in which a plurality of color ink regions such as yellow (Y), magenta (M), cyan (C), and black (K) are sequentially formed on a belt-like sheet, The sensor 8f detects the color of the ink area on the ink ribbon and cues the area, and sublimates the ink on the ink ribbon by heating the thermal head corresponding to the image information of the image to be printed with each ink color. By melting, the image is printed by thermal transfer onto the substrate.

  As a method for cueing the ink area, a positioning detection mark is provided in each ink area, and this is detected by an optical sensor, or positioning is performed only for an ink area of a specific color. There is a method in which a detection mark is detected by an optical sensor, and the ink area of each color is positioned by counting the amount of ink ribbon feed based on this position.

Further, when the thermal head is heated and repeatedly sublimates and melts and transfers ink, heat accumulates (stores heat), and the temperature gradually increases.
When the temperature of the thermal head rises due to the thermal storage of the thermal head, the energy for sublimating or melting the ink increases, so that the print density increases with this increase.
That is, when the printing is performed a plurality of times intermittently, there is a problem that the printing density gradually increases with respect to the initial printing density.
Therefore, in order to always obtain a stable print density in a continuous printing operation, it is necessary to perform a correction that suppresses heat storage of the thermal head.
As a correction method, a temperature sensor (thermistor) is incorporated in the thermal head, the temperature of the head is detected by this sensor, and the thermal energy supplied to the thermal head is reduced when the temperature becomes higher than a set value. Has been done.

On the other hand, the density change due to thermal storage of the thermal head causes a problem that, in the case of single-sided printing on the printing material as described above, the printing density printed later becomes higher than the printing density printed earlier. In the case of double-sided printing, this causes another problem.
That is, in the printing operation on the first surface (hereinafter also referred to as the front surface), the temperature of the printed material rises due to the heat applied from the thermal head, and the second surface (hereinafter also referred to as the back surface for convenience). When printing on the second surface, printing is performed on the second surface having a higher surface temperature. Therefore, the print density on the second surface (for example, the back surface) is higher than the print density on the first surface (for example, the front surface). The problem is that the print density on the back side is different.

As a first example of the double-sided printing method, the substrate is paper, and the paper is supplied to the first and second printing units arranged in the transport direction. After printing on the side, there is a method of printing on the back side with the second printing unit, which is disclosed in Patent Document 1.
As a second example of the double-sided printing method, the object to be printed is a resin card. First, the card is transported to a printing unit with a thermal head and printed on the front side, and then the card is printed from the printing unit. A method is known in which the card is ejected and turned upside down by a reversing machine, and the card turned upside down is again carried into the printing unit and subjected to thermal transfer printing on the back side.
In Patent Document 1, the heat generation energy applied to the second thermal head in the second printing unit is made smaller than the heat generation energy applied to the first thermal head in the first printing unit, and printing in the first printing unit is performed. It is described that the printing density on both sides is corrected to be the same in consideration of the temperature of the paper raised by the operation.
JP 2001-199095 A

By the way, in recent years, higher-speed color duplex printing has been demanded for thermal transfer printing apparatuses.
The density change due to the heat generation energy supplied to the thermal head as described above becomes more significant as the printing speed is higher, and more precise and highly accurate density correction is required.

On the other hand, in the case of color printing, as described above, printing is performed using an ink ribbon having ink areas of a plurality of colors, but the temperature of the printing surface during printing and the applied heat from the thermal head added thereto are added. Even if the ink transfer temperature (this temperature is, of course, the sublimation temperature of the ink or higher) determined by the temperature rise due to is the same, printing is performed at a different density for each ink color.
This is because the sublimation start temperature is different for each ink.
Therefore, with the conventional density correction, although the density of the entire printed image can be corrected to some extent, it is not possible to correct the density characteristics that differ for each color, and density unevenness based on the characteristics cannot be avoided. This is, for example, density unevenness for each color such that the yellow (Y) color is dark and the magenta (M) color is light.

In addition, the temperature rise on the second surface after printing on the first surface differs depending on the heat transfer characteristics of the material of the printed material, so the printing density on the front and back surfaces varies depending on the material of the printed material, There is also a problem that the density is different for each color.
In color double-sided printing, although the card made of resin (mainly PVC (vinyl chloride)) is often used, PC in the case of other materials such as PET (polyethylene terephthalate) cards and transparent cards A card made of (polycarbonate) is also used.
In this case, there is a problem that the density of each color in the printed image differs depending on the card material, and there is room for improvement as a printing apparatus in order to ensure versatility.

  Therefore, the problem to be solved by the present invention is that even when color double-sided printing is performed on a substrate, the print density does not differ on both sides, and the density unevenness of each color of the printed card is different. It is an object of the present invention to provide a thermal transfer printing apparatus in which no occurrence occurs.

In order to solve the above problems, the present invention provides the following thermal transfer printers [1] and [2].
[1] Ink (Y, M, C, K, L) in each of the ink regions in the ink ribbon (9) having ink regions corresponding to each of a plurality of colors of ink (Y, M, C, K, L) Is a thermal transfer printing apparatus that performs printing by sequentially transferring heat to a predetermined surface of the printing member (1),
The predetermined surface is one surface (1a) of the member to be printed and the opposite surface (1b). After printing on the one surface (1a), printing on the opposite surface (1b) is performed. A thermal head (8d) for heating the ink area; and a control unit (20) for controlling the amount of thermal energy applied to the thermal head (8d). Based on the amount (Vcor) of thermal energy applied to the thermal head (8d) in printing on (1a), the thermal energy applied to the thermal head (8d) in printing on the opposite surface is set for each of the plurality of colors. The thermal transfer printing apparatus (50) is characterized in that control is performed for each thermal transfer operation of ink (Y, M, C, K, L).

[2] A temperature rise value (ΔTc) of the opposite surface (1b) that rises due to printing on the one surface (1a) is obtained, and each of the plurality of inks (Y, M, Y) is obtained based on the temperature rise value (ΔTc). C, K, and L) are provided with thermal energy setting means (23) for setting a color-specific thermal energy amount to be applied to the thermal head (8d), and the control unit (20) includes the thermal energy setting means ( 23) The thermal energy applied to the thermal head (8d) in printing on the opposite surface based on the color-specific thermal energy amount (Ecor) set in step 23) is used for each of the plurality of color inks (Y, M, C, The thermal transfer printing apparatus (50) according to [1], wherein the thermal transfer printing apparatus (50) is controlled for each thermal transfer operation of K, L).

  According to the present invention, even when color double-sided printing is performed on an object to be printed, the printing density does not differ on both sides, and density unevenness for each color of the printed card does not occur. There is an effect.

The preferred embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a structural diagram illustrating an embodiment of a thermal transfer printing apparatus according to the present invention.
FIG. 2 is a view for explaining an ink ribbon used in an embodiment of the thermal transfer printing apparatus of the present invention.
FIG. 3 is a schematic flowchart for explaining density correction in the embodiment of the thermal transfer printing apparatus of the present invention.
FIG. 4 is a block diagram for explaining an embodiment of the thermal transfer printing apparatus of the present invention.
FIG. 5 is a graph for explaining the sublimation start temperature of the ink of the ink ribbon used in the embodiment of the thermal transfer printing apparatus of the present invention.

First, the overall configuration of an embodiment of the thermal transfer printing apparatus of the present invention will be described with reference to FIG. Further, in this figure, a plurality of cards 1 are shown on the operation path, but the card positions in each operation are shown. In this case, (1) is attached to reference numeral 1.
The thermal transfer printing apparatus 50 includes a main body portion 50A having a housing 51 and a card stacker portion 50B attached to an outer surface of the housing 51 in appearance.
Hereinafter, the internal configuration of the housing 51 will be described.

A card cassette 2 capable of storing a plurality of cards 1 to be printed as shown in FIG. 1 is provided on the opposite side of the card stacker unit 50B.
The card cassette 2 is detachable so that it can be removed when the card is replenished.
The card 1 is a rectangular IC card or magnetic recording card, and is stored in the card cassette 2 so that the short side thereof is the front side of the figure.
The cards 1 are taken out one by one from the bottom surface of the card cassette 2 by the supply roller 3, passed between the pair of cleaning rollers 4, and carried into the reversing machine 5.
The reversing machine 5 can be conveyed to the encoder unit 6 after rotating 90 ° clockwise with the card 1 fixed.

The encoder unit 6 includes a magnetic encoder 6a, a contact type IC encoder 6b, and two pairs of conveying rollers 6c.
In this figure, the IC encoder 6b is arranged on the right side of the card 1, which corresponds to the case where the card 1 is an ISO standard card, but is arranged on the left side of the card 1 in the case of a JIS standard card. Is done.
The card 1 magnetically or IC-recorded by the encoder unit 6 is conveyed again to the reversing machine 5 by the conveying roller 6c when the recording is correctly performed. Then, the reversing machine 5 rotates the card 1 90 degrees counterclockwise to make it a horizontal position.

On the other hand, if the recording is not correctly performed on the card 1 by the encoder unit 6, the card 1 is determined to be defective, and the reversing machine 5 stops at an angular position where the card 1 can be discharged from the discharge port 7, and the The defective card 1 is discharged from the discharge port 7.
The normal card 1 placed in the horizontal position by the reversing machine 5 is conveyed to the printing unit 8 by a pair of conveying rollers 5 a in the reversing machine 5.

Here, thermal transfer printing on the card 1 in the printing unit 8 will be described.
The printing unit 8 includes two pairs of transport rollers 8a, a platen roller 8c disposed between them along the transport path, a thermal head 8d disposed at a position facing the platen roller 8c, and the thermal head 8d. And a pair of guide poles 8e for guiding the ink ribbon.
The ink ribbon 9 is suspended through the pair of guide poles 8e so as to pass between the platen roller 8c and the thermal head 8d, and both ends of the ink ribbon 9 are respectively provided with a supply reel 10 and a take-up reel. 11 is wound around.
One surface of the ink ribbon 9 is an ink application surface 9a, and the ink application surface is suspended so as to face the platen roller 8c.

The ink application surface 9a of the ink ribbon 9 will be described with reference to FIG.
The ink ribbon 9 is made of a total of four inks on a belt-like base film 9b: sublimable yellow (Y), magenta (M) and cyan (C) ink, and meltable black (K) ink. In addition, a total of five colors of ink, including a meltable protective ink (L) for protecting the printed surface after printing, are applied periodically as a unit of printing screen.
The size of each ink application surface is set slightly larger than the printing range of the card 1.

Returning to the description of the operation again, the card 1 carried into the printing unit 8 by the conveying roller 5a of the reversing machine 5 is the ink application surface 9a of the ink ribbon 9 and the first printing surface 1a of the card 1 (on the upper surface in the figure). And also referred to as a surface for convenience).
At that time, when the rear end of the card 1 is detected by the sensor 8b, the transport roller 8a stops and the card 1 is held at that position. This position is a printing start position on the first printing surface 1a of the card 1.

On the other hand, the ink ribbon 9 is driven by a drive source (not shown) in the direction of being wound around the take-up reel 11, and the leading end position 9 c of the yellow (Y) region of the ink ribbon 9 (adjacent print screen protective ink (L)). Is bordered with the thermal head 8d and stops at that position. A known method can be applied to the color detection and positioning of the ink ribbon 9.
When the tip position 9c of the yellow (Y) area of the ink ribbon 9 coincides with the thermal head 8d, the thermal head 8d moves in the direction of the platen roller 8c, and the ink ribbon 9 and the card 1 are moved to the platen roller 8c. Press on.

  A signal corresponding to a yellow (Y) component in an image to be transferred and printed is sequentially supplied to the thermal head 8d from an image signal processing circuit (not shown), and the platen roller 8c and the take-up reel 11 are not shown. By rotating and driving the card 1 and the ink ribbon 9 according to an instruction from the unit, the image of the yellow (Y) component is transferred to the predetermined printing area 1a1 on the first printing surface 1a of the card 1.

Next, while the thermal head 8d is separated from the platen roller 8c, the transport roller 8a is reversed, and the card 1 is returned to a position where the rear end is detected by the sensor 8b.
Then, magenta (M), cyan (C), and black (K) are repeatedly transferred in the same process as the above-described yellow (Y) ink transfer, and color printing on the first printing surface 1a is completed. To do.
Furthermore, if necessary, the protective ink (L) for protecting the printing surface is transferred by the same process.

  When the printing is single-sided printing and the printing is completed only on the first printing surface 1 a of the card 1, the card 1 is discharged from the card discharge port 13 by the pair of discharge rollers 15 and stacked on the card stacker 14.

Next, a case where printing is performed on the second printing surface 1b of the card 1 (the lower surface in FIG. 1 and also referred to as the back surface for the sake of convenience) will be described.
The card 1 on which the color printing on the first printing surface 1a is completed is returned to the reversing machine 5 and held there. Then, the reversing machine 5 rotates 180 ° in this state, reverses the card 1 and turns it back into the printing unit 8.
Then, color thermal transfer printing is performed on the second printing surface 1 b (back surface) of the card 1.
At that time, the printing operation of the card 1, the ink ribbon 9, the platen roller 8c, and the like is the same as in the case of printing on the first printing surface 1a (front surface) described above.
However, at the time of printing on the second printing surface 1b, the temperature of the card 1 is increased by the printing operation in the thermal transfer printing on the first printing surface 1a, so that the printing density of the ink of each color is not increased. Correction is performed so as to suppress the energy supplied to the head 8d.

The series of printing operations and the like detailed above are controlled by a control unit (CPU) 20 provided in the main body 50A. Further, basic data, programs, and the like necessary for control are stored in a storage unit (memory) 21 that is also provided in 50A.
Further, a communication means that enables communication with the outside may be provided. In this case, it is needless to say that the above-described control or the like may be performed from an external control device or the like.

Here, the configuration of the thermal transfer printing apparatus 50 of the embodiment will be described with reference to FIG. 4 which is a block diagram.
4A, the thermal transfer printing apparatus 50 includes the control unit 20 that controls a series of operations as described above.
The controller 20 receives signals from a sensor group 8g such as a sensor 8b for detecting the position of the card 1 and a sensor 8f for positioning the ink ribbon.
The control unit 20 drives a drive source group M of a plurality of motors (not shown) connected to the supply roller 3, the platen roller 8c, the cleaning roller 4 and the like based on an input signal from the sensor group 8g. Control.
Further, the control unit 20 controls the energization amount to the thermal head 8d to the thermal head driving unit 8h so that predetermined thermal energy is supplied to the thermal head 8d.

The input unit 22 is for a user to input a setting value or the like from the outside, and the input signal is sent to the control unit 20.
The correction amount setting unit 23 cooperates with the control unit 20 to set the correction amount of the thermal energy supplied to the thermal head 6d and the corrected thermal energy.
The controller 20 controls energization so as to supply the thermal head 6d with thermal energy corrected according to the correction amount.

Details of the correction amount setting unit 23 are shown in FIG. The correction amount setting unit 23 is based on a print information acquisition unit 23a that acquires print information indicating whether or not printing has been performed for each color from the control unit 20, and the print information acquired by the print information acquisition unit 23a. A residual heat amount setting unit 23b that sets the amount of residual heat for each color, a correction reference amount setting unit 23c that calculates a correction reference amount by summing up the residual heat amounts set by the residual heat amount setting unit 23b, and the correction reference amount setting unit 23c And a correction amount determination unit 23d for determining a final correction amount for each color based on the correction reference amount obtained in step 1 and the density characteristic data of each color obtained from the function or table stored in the storage unit 21. is doing.
The correction amount setting unit 23 will be described in detail in the following description of the correction processing flow.

FIG. 3 is a schematic diagram illustrating a correction processing flow when performing thermal transfer printing on the second printing surface 1b of the card 1 in the thermal transfer printing apparatus of the embodiment.
In this flow, the control of each process is executed by the control unit (CPU) 20, the storage unit (memory) 21, and the correction amount setting unit 23 that are also provided in the thermal transfer printing apparatus 50 and that also perform drive control of conveyance and the like. However, as described above, the communication unit may be provided and controlled by an external control unit or the like.

In the figure, process <1> is a step for obtaining the presence / absence of printing for each color as print information. This is executed by the print information acquisition unit 23a and the like.
Specifically, it is detected whether or not the color ink (Y), (M), (C), the black ink (K), and the protective ink (L) are printed on the first printing surface 1a of the card 1, respectively. To do.

Process <2> is a step of setting a factor-specific residual heat amount according to the print information obtained in process <1>. This is executed by the remaining heat amount setting unit 23b and the like.
This factor-specific residual heat amount indicates the preheat amount for each color during printing on the first printing surface 1a.
Specifically, taking Y printing as an example, when Y color printing is performed, the amount of remaining heat Vy associated with the printing is set, and when there is no printing, the preheating amount is set to zero.

This remaining heat amount will be described.
The thermal transfer printing apparatus 50 of the embodiment performs an operation of passing the card 1 between the thermal head 8d and the platen roller 8c, for example, when transferring (printing) Y-color ink.
Therefore, in order to consider the amount of heat applied from the thermal head 8d to the card 1 during this operation, this residual heat amount Vy is set.
Similarly, the remaining heat amounts Vm, Vc, Vb, and VL are set for the other colors.

Process <3> is a step for obtaining a correction reference amount by totalizing the amount of residual heat set in process <2>. This is executed by the correction reference amount setting unit 23c and the like.
This corrected reference heat amount is obtained as a total heat amount Vcor based on energization to the thermal head 8d when the printing operation for the first printing surface 1a of the card 1 is executed.
This total heat quantity Vcor is the sum of the residual heat quantities [Vy,..., VL or 0 (zero)] selected according to the presence or absence of printing of each color, as shown in the note of FIG.

Process <4> is a step of determining a specific correction amount for each color and thermal energy Ecor for each color to be applied to the thermal head 8d from the correction amount based on the correction reference amount Vcor obtained in process <3>. . This is executed by the correction amount determination unit 23d and the like.
As described above, the ink sublimation start temperature is different for each color. Further, the energization rate of the current applied when printing is performed while maintaining a predetermined gradation is different for each color.
Therefore, in each color ink, the relationship between the amount of residual heat applied and the actually obtained density is obtained in advance as a function (FY, FM,..., FL), and the correction obtained in <Process 3> using this function. The correction amount is obtained from the reference heat amount. This correction amount is given as a ratio (%), for example.
The functions (FY, FM,..., FL) may be stored in the storage unit 21 in advance, and may be obtained by calculating the correction amount using the function each time printing is performed, or a table of calculation results obtained in advance. May be stored in the storage means 21.

Next, this correction amount will be described in detail with reference to FIG.
As described above, the sublimation start temperature differs depending on the ink color. For the sake of easy understanding, this will be described using the temperature control graph of the thermal head, representative of the two colors yellow (Y) and magenta (M). To do.

FIG. 5 is a graph showing the relationship between the one-line energization period during printing and the temperature TH of the heating element of the thermal head controlled during that period.
A solid line corresponds to yellow (Y), and a broken line corresponds to magenta (M).
As can be seen from this figure, the sublimation start temperature Ty0 of the yellow (Y) ink is lower than the sublimation start temperature Tm0 of the magenta (M) ink. That is, the sublimation start temperature is different.
Therefore, the temperature rising gradient from the temperature base point TH0 of the heating element temperature TH is set differently for each color so as to start sublimation at the same timing.

Further, the temperature TH is maintained at the maintenance temperatures Ty1 and Tm1 at which the predetermined print density is obtained after ink sublimation. The difference (YΔt, MΔt) between this temperature and the sublimation start temperature, that is,
YΔt = Ty1-Ty0
MΔt = Tm1−Tm0
Also different for each color.
This is due to the fact that each color has a different γ characteristic and is adjusted to this.
Further, the energization rates (Yduty, Mduty) for maintaining this temperature difference (YΔt, MΔt) within the gradation energization period are also different values.

Accordingly, the sublimation energies Ey and Em required for printing are respectively
Ey = YΔt × Yduty × Y number of gradations Em = MΔt × Mduty × M number of gradations

The fact that the temperature of the second print surface increases due to the printing on the first print surface means that the temperature base point TH0 in this graph increases.
On the other hand, since the sublimation start temperatures Ty0 and Tm0 and the maintenance temperatures Ty1 and Tm1 do not change, the surplus energy ΔEy and ΔEm to be considered due to the temperature increase of the second printing surface is the temperature increase of the second printing surface as ΔTc. Then
ΔEy = ΔTc × Yduty × Y number of gradations ΔEm = ΔTc × Mduty × M number of gradations.

Since the correction in this embodiment is a method performed in the gradation cycle, the correction amount (Y_cor, M_cor) of each color is
Y_cor = −ΔEy = −ΔTc × Yduty
M_cor = −ΔEm = −ΔTc × Mduty
By doing so, it is possible to perform printing while offsetting the surplus energy.

In this case, the temperature rise of the second printing surface should be set to an optimum value according to the material or thickness of the substrate (card or the like), specifically according to the heat capacity or temperature gradient. Therefore, extremely accurate correction is possible.
The storage unit 21 stores values such as temperature characteristics in advance. However, when the material or shape of the printing material is changed, the value input by the user from the input unit 22 (see FIG. 4) is replaced. Or, it is good also as a structure memorize | stored in the memory | storage part 21 collectively.

  As described above, the correction amount described in detail is to obtain an independent correction amount for each color. However, in a case where a simple correction is sufficient, a color that approximates the correction amount may be processed with the same correction amount.

Next, an example of correction amount setting in the thermal transfer printing apparatus 50 of the embodiment will be described.
This apparatus sets the following correction amounts based on the density characteristics of the ink used.
When transferring in addition to the printing operation, a common correction value of −0.28% is applied to yellow (Y), magenta (M), and cyan (C), and −0.08 is applied to black (K). % Is applied, and -0.41% is applied for the protective ink (L).
Therefore, the correction amount E when executing the transfer printing on the second printing surface 1b is
E = −0.28 × 3-0.08−0.41 = −1.33 (%).

As described above, the energy supplied to the thermal head 8d at the time of printing each color is corrected based on the correction amount of each color obtained by the detailed configuration and method, and printing on the second printing surface is performed.
As a result, when printing on the second printing surface whose temperature has been raised by printing on the first printing surface of the card, in addition to the temperature rise on the surface and the image content to be printed, it is obtained for the increased temperature. Since the energy supplied to the thermal head is corrected in consideration of the difference in print density for each color, there is no uneven color density regardless of the number of printed sheets, as well as the first print surface and the second print surface. The unevenness of color density with respect to the printing surface is eliminated, and an extremely high-quality double-sided printing card can be obtained.

  In addition, even if there are colors that are not printed, correction is made in consideration of the amount of heat applied to the card during the printing operation, so a stable print image without color density unevenness can be applied to any print image. An image capable of obtaining a printed double-sided printing card can be obtained.

  In addition, functions and tables that serve as the basis for obtaining correction amounts can be arbitrarily optimized for different printing speeds, different card materials and thicknesses (different thermal properties), and different ink types. An extremely versatile thermal transfer printing apparatus can be obtained.

The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.
For example, the ink of the ink ribbon has been described as an example of the sublimation type, but it goes without saying that it may be a melt type.

1 is a structural diagram illustrating an embodiment of a thermal transfer printing apparatus according to the present invention. It is a figure explaining the ink ribbon used in the Example of the thermal transfer printing apparatus of this invention. It is a schematic flowchart explaining density correction in the embodiment of the thermal transfer printing apparatus of the present invention. It is a block diagram explaining the Example of the thermal transfer printing apparatus of this invention. It is a graph explaining the sublimation start temperature etc. of the ink of the ink ribbon used in the Example of the thermal transfer printing apparatus of this invention.

Explanation of symbols

1 card (substrate)
1a First printing surface (front surface)
1a1 Print area 1b Second print surface (back surface)
2 Card cassette 3 Supply roller 4 Cleaning roller 5 Reversing machine 6 Encoder unit 6a Magnetic encoder 6b IC encoder 6c Conveying roller 8 Printing unit 8b Sensor 8c Platen roller 8d Thermal head 8e Guide pole 8f Sensor 8h Thermal head drive unit 9 Ink ribbon 9a Ink Coating surface 9b Base film 14 Card stacker 20 Control unit (CPU)
21 Memory (memory)
22 Input unit 23 Correction amount setting unit 23a Print information acquisition unit 23b Remaining heat amount setting unit 23c Correction reference amount setting unit 23d Correction amount determination unit 50 Thermal transfer printer 50A Main unit 50B Card stacker unit 51 Case

Claims (2)

A thermal transfer printing apparatus that performs printing by sequentially transferring the ink of each ink region in an ink ribbon having an ink region corresponding to each of a plurality of colors of ink onto a predetermined surface of a printing member,
The predetermined surface is one surface of the member to be printed and its opposite surface, and after printing on the one surface, it is configured to perform printing on the opposite surface,
A thermal head for heating the ink area;
A control unit for controlling the amount of thermal energy applied to the thermal head,
The control unit
Based on the amount of thermal energy applied to the thermal head in printing on the one surface, the thermal energy applied to the thermal head in printing on the opposite surface is controlled for each thermal transfer operation of the plurality of colors of ink. A thermal transfer printing device. Thermal energy for obtaining a temperature rise value of the opposite surface that rises due to printing on the one surface and setting a color-specific thermal energy amount to be applied to the thermal head for each of the plurality of colors of ink based on the temperature rise value Comprising setting means,
The control unit applies thermal energy applied to the thermal head in printing on the opposite surface based on the color-specific thermal energy amount set by the thermal energy setting unit for each thermal transfer operation of the plurality of colors of ink. The thermal transfer printing apparatus according to claim 1, wherein the thermal transfer printing apparatus is controlled.

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