JPH01237165A - Color thermal transfer recorder - Google Patents

Abstract

PURPOSE:To allow thermal transfer recording to be performed in color and at high speed with a simple and compact structure by maintaining an electric current to be supplied at a constant value and changing a drive duration of time by means of a pulsed signal. CONSTITUTION:A thermal head 3 with a plurality of heat-generating elements is allowed to heat a transfer sheet consisting of two different kinds of heat- melting ink layer with different melting points applied on a base, and these inks are melted and transferred to a material to be transferred. An image signal containing color information of each image of an original image to be recorded, is input to a pulse width control circuit 1, and the pulse width control circuit 1 outputs a pulsed signal with a pulse width which is set based on an entered image signal per pixel. A thermal head drive circuit 2 is allowed to drive the heat-generating elements of the corresponding pixels by time set by pulse width. Consequently, each heat-generating element permits a calorific value to be changed by the pulsed width to be applied to each heat-generating element without changing an electric current value. After this, the heat- generating elements melt the heat-melting ink at a temperature corresponding to each melting point to perform multicolor thermal transfer recording.

Description

[Detailed description of the invention] (Table of contents) Overview Industrial field of application Conventional technology Problems to be solved by the invention Means for solving the problems (Fig. 1) Effect (Fig. 1) Examples (Fig. 2) ~Figure 6) Effects of the invention [Summary] A transfer sheet formed by applying two or more types of heat-melting inks having different melting points on a base material in a layered manner is heated by driving a thermal head having a plurality of heating elements. Regarding a color thermal transfer recording device that melts and transfers this ink to a transferred object, the purpose of this invention is to provide a color thermal transfer recording device that can perform color thermal transfer at high speed with a simple structure, and to create a color that corresponds to each pixel of the original image. a pulse width control circuit that outputs a pulse signal having a pulse width determined based on an image signal containing information; and a thermal head drive circuit that drives the heating element at a corresponding pixel position based on the pulse width of the pulse signal. This is a configuration having the following.

[Industrial application field]

The present invention relates to a color thermal transfer recording device, and in particular, drives a thermal head having a plurality of heating elements to heat a transfer sheet formed by coating two or more types of heat-melting inks with different melting points on a base material in layers. The present invention relates to a color thermal transfer recording device that performs melt transfer onto a transfer target.

[Conventional technology]

Conventionally, color thermal transfer recording devices use a transfer sheet that is painted in sequential order, and when recording, the first color is recorded, and then the second color is overlaid and recorded, and this process is repeated. There was one that recorded multiple colors, so-called surface sequential recording.

In addition, there are line printer devices that record multiple colors by having multiple recording units of sheet rolls, thermal heads, and platens for each different color, and line printers that record multiple colors on a sheet-like base material. This is a color thermal transfer recording device that drives a thermal head to heat a transfer sheet made of a layered ink and melts it and transfers it to the transfer object. There was one that supplied it to an element to drive a thermal head.

(Problems to be Solved by the Invention) By the way, conventional color thermal transfer recording devices that perform field-sequential recording require time to reciprocate the recording paper as the transfer target, which slows down the recording speed. There is a problem in that an apparatus having a plurality of recording units including separate sheet rolls, thermal heads, and platens for each color increases the size of the apparatus.

Furthermore, unlike conventional color thermal transfer recording devices, which print multicolors on a transfer material by driving a thermal head onto a transfer sheet made by layering two or more types of heat-melting inks with different melting points on a base material, However, since the thermal head is driven by supplying currents of different magnitudes to each heating element according to the melting point, there is a problem in that it is not possible to control the intensity of each heating element. Ta.

Therefore, it is a technical object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide a color thermal transfer recording device that has a simple structure and can perform color thermal transfer at high speed. be.

[Means to solve the problem]

In order to solve the above technical problems, the present invention drives a thermal head 3 having a plurality of heating elements as shown in FIG. In a color thermal transfer recording device that heats a transfer sheet coated with ink and melts and transfers this ink to a transfer object, the ink has a pulse width determined based on an image signal containing color information corresponding to each pixel of the original image. The apparatus includes a pulse width control circuit 1 that outputs a pulse signal, and a thermal head drive circuit 2 that drives each heat generating element at a corresponding pixel position based on the pulse width of the pulse signal.

(Operation) When performing color thermal transfer recording according to the present invention, as shown in FIG. 1, an image signal containing color information of each pixel of an original image to be recorded is input to the pulse width control circuit 1.

The pulse width control circuit 1 outputs a pulse signal having a pulse width determined based on the input image signal for each pixel.

Here, the pulse width determined based on the image signal refers to each melting point applied to the transfer sheet in order to display the color information represented by the image signal on the transferred object, and each heating element of the thermal head. It is determined based on the properties of the motor and the energy used to drive it.

The thermal head drive circuit 2 drives the heating element of the corresponding pixel for a time determined by the pulse width.

As a result, each heating element changes the amount of heat generated by the pulse width applied to each heating element without changing the current value, melting the thermofusible ink at a temperature corresponding to each melting point, and performing multicolor thermal transfer recording. be able to.

(Example) A line printer device according to an example of the present invention will be described.

As shown in FIG. 2, this apparatus includes a color image memory 14 that stores color information regarding the color of each pixel of an original image to be recorded, and an image that contains color information read out from the color image memory 14. It has a thermal head control unit 20 that controls the thermal head 13 of the printer device based on signals, a thermal head 13 in which a plurality of heating elements are arranged in a line, and a transfer sheet roll 17 and a transfer target. It has recording paper 19 as a body and a platen 18.

Further, the thermal head control section 20 includes a readout control section 15 that sequentially reads out image signals for each pixel in the order of scanning lines from the color image memory 14 and outputs them, and a readout control section 15 that sequentially outputs image signals from the color image memory 14 in the order of scanning lines, and a readout control section 15 that outputs a corresponding image signal based on the read out image signal. a pulse width control circuit 11 that sequentially outputs a pulse signal having a width for each pixel;
The thermal head drive circuit 12 drives a heat generating element at a corresponding pixel position based on the output pulse width.

Further, as a transfer sheet used in this example, for example, a fifth
There is a two-color transfer sheet shown in the figure or a three-color transfer sheet shown in FIG.

The two-color transfer sheet is a black coloring material with a melting point of 150 on the base material 61.
An ink layer A62 made of a binder with a high melting point of 70° C. and an ink layer B63 made of a red coloring material with a low melting point binder of 70° C. are laminated in this order.

Further, a pigment is used as the coloring material of the high melting point ink layer A62 on the side of the base material 61, and a low melting point ink layer B63 formed thereon.
A dye is used as the coloring material, and an incompatible material is used as the binder of the two ink layers.

Here, as the base material 61, polyester film, polycarbonate, polyamide, nylon, polyimide,
Capacitor paper or the like is used.

Pigments used as coloring materials for the high melting point ink layer A62 include general inorganic or organic pigments, and dyes used as coloring materials for the low melting point ink layer 863 include oil-soluble dyes, disperse dyes, etc. .

As the incompatible binder materials, for example, an oil-soluble wax-based binder is used on one side, and an oil-insoluble resin-based binder is used on the other side.

Wax binders include beeswax, lanolin,
Natural waxes such as carnauba wax, candelilla wax, and montan wax; Petroleum waxes such as paraffin wax and microcrystalline wax; Synthetic waxes such as oxidized wax, ester wax, and low molecular weight polyethylene; Lauric acid, palmitic acid, stearic acid, etc. In addition to higher fatty acids, higher alcohols, esters, amides, and mixtures thereof can be used.

Examples of resin binders include polyamide resin, polyester resin, epoxy resin, polyurethane resin,
Polyacrylic resins, polystyrene resins, SBR, phenolic resins, natural rubber, vinyl acetate resins, and mixtures thereof can be used.

In this way, the coloring material of the high melting point ink layer A62 is a pigment, and the coloring material of the low melting point ink layer B63 is a dye, and since the binders of these two ink layers are not compatible, color mixing between the two colors is prevented. Can be done. That is, in general, pigment-based coloring materials have larger particles than dye-based coloring materials and do not dissolve in the heat-melting binder used for thermal transfer, and the color becomes younger by dispersion.

Therefore, if a pigment is used on the high melting point ink layer A62 side,
When the low melting point ink layer B63 is melt-transferred with low heating energy, the pigment on the high melting point ink layer A62 side does not dissolve into the low melting point ink layer B63 side, and color mixing does not occur.

Furthermore, "If the same type of material is used for the heat-melting binders of the two ink layers A62 and B63, color mixing will occur due to mixing and adhesion due to melting or softening, but the low melting point ink layer B63
Since incompatible materials are used, for example, a wax-based binder is used for the ink layer A62, and a resin-based binder is used for the high melting point ink layer A62, adhesion between the two layers can be prevented.

A high melting point ink layer A62 and a low melting point ink layer B63 having the following composition ratios are coated on a 6 gm thick polyethylene terephthalate film (substrate 61) using an ink coating device (barcoder) so that each has a thickness of 3 gm.

Low melting point ink layer - Paraffin wax 30ffi4LJ - Amide wax 65 parts by weight - Dye (oil-soluble dye) Red 5 parts by weight High melting point ink layer - Polyester resin 70 parts by weight - Polyamide resin 10 parts by weight - Pigment (carbon black) 20 parts by weight The low melting point ink layer 863 uses paraffin wax with a melting point of about 60°C and amide wax with a melting point of about 77°C, so that the melting point of the entire ink layer is about 70°C. On the other hand, the high-melting point ink layer A62 also had different melting points, and was set to have an overall melting point of about 150°C.

Recording was evaluated using a printer evaluation machine using the two-color thermal transfer ink sheet obtained in the above manner. Recording power 0.3w/
dot, period 10m5/1ine, recording pulse width 1
ms and 4 ms, it was possible to obtain a red image without color mixture under the condition of a pulse width of 1 ms with low thermal energy, and a black image under the condition of a pulse width of 4 ms with high thermal energy without color mixture.

In addition, when obtaining a three-color thermal transfer ink sheet, as shown in FIG.
A high melting point ink layer C72 using a dye as a coloring material, a medium melting point ink layer D73 using a pigment as a coloring material, and a low melting point ink using a dye as a coloring material, each having a thickness of 3 m from the side. The layer E74 is made of a material in which the binders of adjacent ink layers are incompatible.

High melting point ink layer C72 (melting point 160°C), amide wax (melting point 160°C) 95 parts by weight, black dye 5 parts by weight Medium melting point ink layer D73 (melting point 120°C), polyamide resin (melting point 130°C) 80 parts by weight Pigment (cyan) 20 parts low melting point ink layer E74 (melting point 70°C) Paraffin wax 30 parts by weight Amide wax (melting point approximately 77°C) 65 parts by weight Dye (oil-soluble dye) Red 5 parts by weight, medium melting point In the case of ink layer D73, if cyan disperse dye or oil-soluble dye is used, it will dissolve in ink layers C72 and D74, so it is recommended to use pigment. good.

The recording pulse width was set to 1 ms, 3 ms, and 5 ms, and recording was performed under the same conditions as with the two-layer ink sheet. When the recording pulse width was 1 ms, O, D
, pink color with a value of 1.2, O, D when the recording pulse width is 3 ms, blue color with a value of 1.3, and a recording pulse width of 5 ms.
In this case, a three-color recording of O, D, and black with a value of 1.5 is obtained.

FIG. 3 is a diagram showing the internal configuration of the pulse width control circuit 11, thermal head drive circuit 12, and thermal head 13 according to this embodiment shown in FIG. 2.

The pulse width control circuit 11 is a shifter that sequentially and serially inputs the pulse number 33 value while moving it based on a clock signal and outputs the pulse signal value held for one micropulse in parallel to perform serial-parallel conversion. The thermal head drive circuit 12 is configured to include a register Ilb and a latch circuit 11a that holds the pulse signal value for the 1 (Atsushi small pulse), and the thermal head drive circuit 12 uses the pulse signal value held in the latch circuit 11a for printing. Gate element 121b outputs based on a strobe signal input at timing
, 122b, ---12nb, and the gate element 121
The transistors 121a, . . . 12nb receive the pulse signal values outputted by the transistors 121a, .

The thermal heads 13 are arranged in a line, and
A heating element 131. is made of a resistor having a predetermined resistance value, and is supplied with a current by a DC power source ■co having a predetermined voltage value, and the opening/closing of the current is controlled by the transistors 121a, . . . , 12na. ...It has 13n.

Next, the operation of this embodiment will be explained using the time chart of FIG.

For example, an image signal corresponding to each pixel is read out by the readout control section 15 from the color image memory 14 shown in FIG.

The image signal is input to the pulse width control circuit 11.

This image signal is transmitted to the heating element 131 of the thermal head 13.
. . . When there are 1024 13n, the configuration is as shown in FIG. 4(a).

That is, one line consists of bit data of 1024 pixels x 4 columns = 4096 bits (the solid line portion indicates bit "1" and the dotted line section indicates bit "0").

The color image memory 14 stores the first pixel of the 0th column, ... 1024th pixel, the first pixel of the ■th column, ..., the
The data is stored as rl, l rO, in the order of the 1024th pixel in the column, and is read out in this order by the readout control unit 15.

Therefore, the readout control unit 15 sequentially reads out the image signals from the color image memory 14, and stores them in a shift register ll having a storage area for 1024 pixels in the pulse width control circuit 11.
b is sequentially moved bit by bit in synchronization with the clock to hold data for 1024 pixels in the 0th column.

Then, by inputting a data set signal to the latch circuit 11a via a control signal line (not shown) at the timing when the data for 1024 pixels in the 0th column is stored in the shift register llb, the data is stored in the shift register llb. Data is set in latch circuit 11a.

Next, gate elements 121b, 122b, . . . 12nb
By supplying a strobe signal “HII” having a time width of 1 ms from a control circuit (not shown) to
The gate element corresponding to the pixel position of the latch circuit holding " is opened, and the corresponding transistor is driven. That is, in the 0th column, the data is the 1st. Second.
4th. Since the fifth pixel... is "1", as shown in Fig. 4 (b
), gate elements 121b, 122b.

124b, 125b-... are output for 1ms or ii
It becomes H++.

At the same time, the data of the 1024 pixels of the 1st column, which is applied through the data input terminal, is sequentially shifted and stored in the shift register llb, and then set in the latch circuit 11a.

Incidentally, the shifting operation of the 1024 pixels of the shift register llb and the setting operation to the latch circuit 11a are completed within 1 ms.

Therefore, the output of the strobe signal becomes "H11" for another 1 ms, so that the gate elements 121b, 124b,
125b-... becomes "H" for an additional 1 ms.

Thereafter, in the same manner, the gate elements 121b are set corresponding to the data of 1024 pixels in the Ⅰth column and the 0th column.

124b, 125b, . . . become "H'".

After all, the first pixel, the fourth pixel, the fifth pixel...
The heating element of is driven for 4ms, and the second pixel
The heating elements of the third pixel, etc. are driven for a period of 1 ms, and the heating elements of the third pixel, etc. are not driven at all.

In this way, each heating element has a predetermined time width depending on the input data, that is, 4ms for black and 1ms for red.
, white is driven for a time of Oms.

As a result, the amount of heat necessary to melt each ink layer is applied, and the ink of the corresponding color is transferred to the recording paper.

In this way, in this embodiment, a conventionally used circle head drive device capable of pulse width driving is used, and the data given to it is simply assigned a different number of bits for each color as shown in FIG. By controlling the pulse width, it is possible to transfer only a desired ink layer.

Further, although the explanation has been made assuming that the data shown in FIG. 4(a) is stored in the color image memory 14 in advance, for example, the color image reading device
The data may be stored in an image memory (line buffer) of 024 pixels x 4 columns.

In this case, a black pixel is stored as a bit "1" in each column, a red pixel is stored as a bit "1" only in the first column, and a white pixel is stored as a bit "0" in each column.

Also, this can be achieved in the same manner in the case of a three-color ink sheet, except that the number of data strings increases.

〔Effect of the invention〕

As explained above, in the present invention, when each heating element of a thermal head is driven to melt and transfer two or more types of thermal transfer sheets having different melting points, a pulse signal is used to melt and transfer the sheets.
Since the current value to be supplied is constant and the driving time width is varied, thermal transfer recording can be performed in color at high speed with a simple structure and without increasing the size of the device.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the invention, Fig. 2 is a block diagram showing a thermal transfer recording device according to an embodiment, Fig. 3 is a diagram showing the internal configuration of the circuit shown in Fig. 2, and Fig. 4 is a time chart. , FIG. 5 is a diagram showing a two-color transfer sheet according to an example, and FIG. 6 is a diagram showing a three-color transfer sheet according to an example. 1.11... Pulse width control circuit 2.12... Thermal head drive circuit 3.13...
Thermal head U-Ryoyo @ l Prisoner φ--1024 Ayu? -----------1234
567519101112''---IWO10221
024+ 2345 Time chart 4th! ! 1m

Claims (1)

[Claims] A thermal head (3) having a plurality of heating elements is driven to heat a transfer sheet formed by applying two or more kinds of heat-melting inks having different melting points on a base material in a layered manner, In a color thermal transfer recording device that melts and transfers this ink to a transfer object, a pulse width control circuit (1) outputs a pulse signal having a pulse width determined based on an image signal containing color information corresponding to each pixel of the original image. ), and a thermal head drive circuit (2) that drives each of the heating elements at the corresponding pixel position based on the pulse width of the pulse signal.