JPH1016274A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer printer in which high image quality multilevel printing is performed with both thermal fusion ink and sublimation ink using a same thermal head. SOLUTION: The thermal transfer printer performs multilevel printing on an ink film coated with a sublimation ink or an ink film coated with a thermal fusion ink by heating the ink in the ink film by means of a thermal head arranged with heating elements 1 and transferring the ink onto a recording paper. The heating element 1 is split into a plurality of sections and has a length L substantially equal to the interval D of the heating element or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printing apparatus for performing multi-tone printing using a heat sublimable ink or a hot melt ink.

[0002]

2. Description of the Related Art In a conventional thermal transfer printing apparatus 10, as shown in FIG. 8, a recording paper 6 and an ink film 7 are pressed against each other by using a thermal head 9 and a platen roller 5, and a heating resistor of the thermal head 9 is formed. (Not shown) is energized to generate heat. With this heat, the ink applied to the ink film 7 is sublimated or melted and transferred to the recording paper 6. When performing color printing, Y (yellow), M (magenta), Cy
Each color is superimposed and printed in the order of (cyan).

When performing multi-tone printing in pixel units with a thermal transfer printing apparatus, when using a thermal sublimation ink, FIG.
The front shape of the heat generating resistor 3 is rectangular as shown in FIG. 9A, or is divided into two as shown in FIG. 9B. On the other hand, when the hot-melt ink is used, FIG.
As shown in FIG. 9C, the front shape of the heat generating resistor 3 is made substantially square, or as shown in FIG. That is, multi-gradation printing has been performed for the heat sublimable ink and the heat fusible ink by using heating resistors having different shapes.

In the case of a thermal sublimation ink, if a heating resistor having a rectangular or divided shape is used, the density gradation shown in FIG. The heat sublimation ink is sublimated into gas by heating the heating resistor, but has a property of hardly diffusing because it is used in close contact at a high temperature. In the case of the hot-melt ink, the area gradation shown in FIG. This hot-melt ink has a property of being melted by heating of the heating resistor and becoming a liquid to be diffused, and has a property of being easily affected by adjacent pixels.

However, in the case of a heat sublimation ink, if a square or heat concentration type heating resistor is used, the density of the heat sublimation ink is insufficient because the sublimation area during heating is hardly diffused, and the density of the heat sublimation ink is insufficient. Need to increase the heating power. Similarly, in the case of a heat-meltable ink, if a rectangular heating resistor is used, the ink transfer area becomes large and the minimum density required for a smaller transfer area cannot be secured. May have a thermal effect on the image quality and image quality may be degraded.

[0006]

In the case of performing multi-tone printing with a hot-melt ink and a hot-sublimable ink, if heat-generating resistors having different shapes are used, it takes time to replace the thermal head according to the ink. , There is a problem. Therefore,
There is a demand for a thermal transfer printing apparatus that can use both the heat-meltable ink and the heat-sublimable ink using the same thermal head and that performs high-quality multi-tone printing. Note that Japanese Patent Application Laid-Open No. 7-112
Japanese Patent Application Publication No. 538 discloses a thermal recording apparatus which uses both a fusion type recording method and a sublimation type recording method, but the present invention provides a thermal transfer type printing apparatus having a different configuration.

[0007]

According to the first aspect of the present invention, there is provided an ink film having a thermal head on which a heating resistor is arranged, wherein an ink film coated with a heat sublimable ink and an ink film coated with a heat fusible ink can be used. In a thermal transfer printing apparatus that performs multi-tone printing by heating the ink with a thermal head and transferring it to recording paper, the heating resistor has a plurality of divided shapes, and the heating resistor length is equal to the heating resistor interval. It is characterized by being substantially equal or less.

According to a second aspect of the present invention, in the thermal transfer printing apparatus according to the first aspect, the ink comprises a heat-fusible ink, and the recording paper comprises a porous recording medium having a porous layer on the surface.

According to a third aspect of the present invention, in the thermal transfer printing apparatus according to the first or second aspect, the heating resistor has a divided shape divided into two, and each of the divided portions has a width of about 65 μm. Is about 100 μm to about 160 μm, and the distance between the heating resistors is about 154 μm.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments shown in the drawings.

FIG. 1 is an enlarged view of a main part of a heating resistor arranged in a thermal head. The heating resistor 1 has a divided shape in which the space between the electrodes 2 and 2 facing each other is divided into two. The width P of each of the divided portions 1A and 1B is 65 μm, and the interval between the heating resistors between the adjacent heating resistors 1 is 2 μm. D is 154 μm. The electrode width H is 145 μm.

An experiment was conducted to determine how the print density characteristics of the heat sublimable ink and the heat fusible ink changed depending on the length L of the heat generating resistor corresponding to between the electrodes 2 and 2 facing each other. Here, the heating resistor is formed in a partial glaze, the heating power is 0.189 W / dot, and the heating area is 0.02 W / dot.
37 mm ² / dot (= 154 μm × 154 μm / do
t).

The printing time for one line is 1
3.3 msec, and the thermal sublimation ink is 33.3 msec.
c. The heating energy at this time is 1 line printing time × heating power ÷ heating area, and the heat-meltable ink is 106 m.
J / mm ² , and the thermal sublimation ink is 265 mJ / mm
It becomes ² . If one line is represented by 256 gradations,
One gradation period To is 13.3 msec /
256 = 52 μsec, and 3 for thermal sublimation ink
3.3 msec / 256 = 130 μsec.

[0014] The heat energy required for maximum density by actual measurement value, the hot-melt ink and 10 mJ / mm ^2, when the heat-sublimation ink and 85 mJ / mm ^2, which optionally heating time t of the same at each gradation On the other hand, the heat-meltable ink is 4.9 μsec, and the heat-sublimable ink is 39 μs.
ec. Actually, the density for each gradation is finely adjusted by the heating time, and, for example, the density characteristic of the color to be used is made a straight line for each gradation or a predetermined curve for correcting the input characteristic of the image signal.

Heating resistor length L = 100 μm, 160 μm
2 and FIG. 3 show the results of the experiment performed for the case of m and 220 μm. The heating time t was set to the above value.

Multi-tone printing is performed by using a recording paper made of a porous recording medium for the heat-meltable ink, and using a recording paper having a receptor layer coated on the surface with a polyester resin for the thermal sublimation ink. Was. In this case, the multi-gradation expression shown in FIG. 4 was obtained.

In the case of the thermal sublimation ink of FIG. 2, each gradation characteristic hardly changes, but the gradation characteristic of L = 100 μm has the highest density and good thermal efficiency. In the case of the hot-melt ink shown in FIG. 3, the gradation characteristic of L = 100 μm shows the best gradient change with the gentlest slope.

Therefore, the length of the heating resistor is L = 10
0 μm is the best, followed by L = 160 μm. L = 220
μm is not suitable for multi-tone printing because the gradient is steep in the case of the hot-melt ink.

As described above, when the heating resistor length L is substantially equal to or less than the heating resistor interval D, high-quality multi-tone printing is performed using both the heat-meltable ink and the heat-sublimable ink. Can be.

FIG. 5 shows a thermal transfer type printing apparatus 3 according to the present invention.
FIG. 2 is a block diagram showing the configuration of a block 0. This thermal transfer printing device 30
The thermal head 20 includes a shift register 20S, a latch circuit 20L, a gate circuit 20G, and a power supply circuit 2.
This power supply circuit 20P includes a heating resistor 1 and an electrode 2 arranged as shown in FIG.

When the interface circuit 11 receives a signal Vp composed of an image signal and a control signal from an image input device (not shown), it separates the image signal Vs and outputs it to the image storage device 15 and controls the image signal Vs from the control signal. The signal Pc is generated and output to the print control signal generator 12. The reference signal generator 13 outputs the reference clock Sc to the address generator 14, the address generator 14 outputs an address signal AD corresponding to the image signal Vs to the image memory 15, and the image memory 15 outputs the address signal AD. The image signal Vs is stored based on the image signal Vs.

When the storage of the image signal Vs by the image storage device 15 is completed, a print start signal Pe is output from the print control signal generation device 12 to the printing device drive system control device 21, and
Based on the drive control signal Pd from the interface circuit 21 and the print start signal Pe, the printing apparatus drive system controller 21
Outputs a drive signal Pa to the printing device driving unit 22, and the printing operation of the thermal transfer printing device 30 is started.

The print control signal generator 12 generates an ink color identification signal Sa at the start of the printing operation and outputs it to the heating signal generator 19, and the reference signal generator 13 reads the image signal Vs read timing signal and the ink color. The control signal Co including the identification signal is output.

The reference signal generator 13 outputs a color signal Cs to the print data converter 16 based on the ink color identification signal, and outputs a reference clock Sc to the address generator 14 based on the read timing signal. The address generator 14 generates an address signal AD based on the reference clock Sc, outputs the address signal AD to the image storage device 15, and reads out the stored image signal Vs in the form of three primary color signals RGB. In recent years, the image signal Vs has been compressed to reduce the capacity of the image storage device 15, and is used as it is at the time of storage, but is converted to three primary color signals RGB at the time of reading and used. In the thermal transfer printing device 30, the image storage device 15 has this conversion function.

The print data converter 16 outputs the three primary color signals R
GB is converted into a printing color signal YMC corresponding to the ink color specified by the color signal Cs. For example, if the color signal Cs is Y
If (yellow) is specified, it is converted to data of this color.

The gradation signal generator 18 outputs a gradation signal St to the parallel / serial converter 17 and the heating signal generator 19 based on the gradation reference signal Cl from the reference signal generator 13. The parallel / serial converter 17 compares the gradation signal St with the print color signal YMC, and outputs the heating data Ds corresponding to the number of the heating resistors to the shift register 20S for each gradation.
Output to Symbol Ck is a timing pulse for the shift register 20S.

The latch circuit 20L latches and holds heating data Ds for one gradation corresponding to the number of heating resistors,
The on / off signal of the power supply circuit 20P is supplied to the gate circuit 20.
Output to G. Symbol Cr is a timing pulse for the latch circuit 20L.

The heating signal generator 19 generates a heating signal Dh for one gradation corresponding to the ink color based on the gradation signal St and the ink color identification signal Sa, and outputs it to the gate circuit 20G. The gate circuit 20G turns on / off the power supply circuit 20P based on the heating signal Dh and the heating data Ds. When the power supply circuit 20P is in the on state, the heating resistor is energized to melt or sublime the ink of the ink film by one gradation. Is transferred onto a recording paper (not shown). This is repeated for the number of gradations,
Repeat for the number of ink colors.

FIG. 6 is a time chart of various signals of FIG. The parallel / serial converter 17 compares the gradation signal St with the printing color signal YMC in synchronization with the comparison signal, and outputs ON if the gradation signal St is equal to or less than the value of the printing color signal YMC.
When the value exceeds the value of the print color signal YMC, the output is turned off to generate the heating data Ds. Heating signal Dh to heating data D
What is controlled by s is Dh-3 or Dh-6 in FIG. Dh-3 corresponds to the case where the value of the gradation signal St is 3, and Dh-6 corresponds to the case where the value of the gradation signal St is 6. In the comparison, since the value of the gradation signal St starts from 0, there are four pulses in Dh-3 and seven pulses in Dh-6.

The heating time t of the heating signal Dh for one gradation is:
It is determined by the density to be set for each ink. For example, FIG.
As shown in FIG.
Control is performed by changing the heating times ta, tb, and tc in (b) and (c).

As the porous recording medium, a Beck smoothness of 5
The substrate has a mean pore diameter of 1 to 10 μm on a substrate having a print surfacity of 3 μm or less for not less than 00 seconds.
What formed the m porous layer may be used. The porous recording medium is described in detail in JP-A-7-125468.

The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment.

[0033]

According to the present invention, high-quality multi-tone printing can be performed using the same thermal head in both the thermal sublimation ink and the hot-melt ink. The trouble of replacing is eliminated. Further, since the same thermal head may be used, the manufacturing cost of the thermal transfer printing device can be reduced.

Further, according to the present invention, by printing on the porous recording medium with the hot melt ink, as shown in FIG. Therefore, it is possible to produce a smooth change in density in multi-tone printing.

In the case of the heat sublimable ink, as shown in FIG. 2, the density is higher and the heat efficiency is better when the heating resistor length L = 100 to 160 μm than when the heating resistor length L = 220 μm. In particular, the gradation characteristic with the heating resistor length L = 100 μm has the highest density, good thermal efficiency, and can reduce the power consumption of the thermal head. In the case of the heat-meltable ink, as shown in FIG. 3, when the heating resistor length L = 100 to 160 μm, the gradient of the gradation characteristic is gentler and the density changes better than when the heating resistor length L = 220 μm. . In particular, the gradation characteristic with the heating resistor length L = 100 μm has the gentlest gradient and a good density change, and the density gradation can be accurately controlled.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of a heating resistor arranged on a thermal head of a thermal transfer printing apparatus according to the present invention.

FIG. 2 is a characteristic diagram of heating energy and print density of a heat sublimable ink when a heating resistor length L is used as a parameter.

FIG. 3 is a characteristic diagram of heating energy and print density of hot-melt ink when a heating resistor length L is used as a parameter.

FIG. 4 is an explanatory diagram showing the gradation of the print density of the heat sublimable ink and the heat fusible ink.

FIG. 5 is a block diagram of a thermal transfer printing apparatus according to the present invention.

FIG. 6 is a time chart of various signals in FIG. 5;

FIG. 7 is a waveform diagram of a heating signal Dh.

FIG. 8 is a basic configuration diagram of a thermal transfer printing apparatus.

FIG. 9 is an explanatory view showing the shape of a conventional heating resistor.

FIG. 10 is an explanatory diagram showing the gradation of the print density of the heat sublimable ink and the heat fusible ink.

[Explanation of symbols]

1,3: heating resistor, 1A, 1B, 3A, 3B: divided portion, 2: electrode, 5: platen roller, 6: recording paper (printing paper), 7: ink film (ink sheet), 8A: for sending Roller 8A Roll-up roller 9 Thermal head 10, 30 Thermal transfer printer 11, Interface circuit (I / F circuit) 12, Print control signal generator 13, Reference signal generator , 14 an address generator, 15 an image storage device, 16 a print data converter, 17 a parallel / serial converter, 18 a gradation signal generator, 19 a heating signal generator, 20 a thermal head,
20G: gate circuit, 20L: latch circuit, 20P: power supply circuit, 20S: shift register, 21: printing device drive system control device, 22: printing device drive unit, D: heating resistor spacing, L: heating resistor length, P: width of the divided portion, H: electrode width.

Claims (3)

[Claims] An ink film coated with a heat-sublimable ink and an ink film coated with a heat-meltable ink are provided, and a thermal head having heating resistors arranged therein is provided, and the ink of the ink film is heated by the thermal head. In the thermal transfer printing apparatus for transferring to recording paper and performing multi-tone printing, the heating resistor has a divided shape divided into a plurality of pieces, and a heating resistor length is substantially equal to or less than a heating resistor interval. A thermal transfer printing device characterized by the following. 2. The thermal transfer printing apparatus according to claim 1, wherein the ink comprises a heat-meltable ink, and the recording paper comprises a porous recording medium having a porous layer on a surface. 3. The heating resistor has a divided shape divided into two, the width of each divided portion is about 65 μm, the length of the heating resistor is about 100 μm to about 160 μm, and the interval between the heating resistors is about The thermal transfer printing apparatus according to claim 1, wherein the thermal transfer printing apparatus has a thickness of 154 μm.