JPH0261911B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thermal transfer recording device that can perform good printing regardless of the smoothness of the ink-receiving surface of recording paper.

[Technical background of the invention and its problems]

There are two types of non-impact recording technology that can print on plain paper: thermal transfer recording and inkjet recording, both of which have been put to practical use, but inkjet recording has some unreliable aspects such as nozzle clogging due to ink drying. On the other hand, the thermal transfer recording method, which thermally transfers solid ink from an ink ribbon to plain paper, is highly reliable and uses a thermal head to press the three components of the thermal head, ink ribbon, and recording paper into contact. As a matter of fact, many products of the type that perform thermal transfer recording have been put into practical use.

A thermal transfer recording device brings an ink ribbon and recording paper into pressure contact via ink, and selectively heats the ink using a heating means such as a thermal head to make it sticky and adhere to the recording paper. An ink image is obtained on recording paper by peeling off the ink, but if recording paper with a large surface unevenness, such as PPC copying machine paper, is used, uneven transfer occurs. As a method to solve this problem, an ink image is transferred from an ink ribbon to an intermediate transfer member with good smoothness, and the ink image is then recorded from the intermediate transfer member onto plain paper (Japanese Patent Laid-Open No. 1986-1999).
127334), but the device configuration is complicated. Furthermore, by using a supercooled substance in the ink that remains in a molten state for a long time relative to the heating pulse time of the thermal head, the penetration time into the recording paper is extended and the ink fixing properties are improved (Japanese Patent Laid-Open No. 51 −
15446) is known, but since a heating means is used after the ink and recording paper are separated, uneven transfer of ink cannot be solved.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, provide a thermal transfer recording device that has a simple device configuration, and is capable of high-quality printing even on recording paper with poor smoothness.

[Summary of the invention]

This invention uses supercooled ink that maintains a melted and sticky state even after heating is completed, and a heating means that selectively heats the ink, and a superimposed ink that transfers the ink adhered to the recording paper onto the recording paper. By providing ink adhesion activating means between the ink ribbon and recording paper peeling means that separates the ribbon and recording paper, after the ink is heated by the heating means, it is melted and sticky due to supercooling properties. While the image is being displayed, the ink that is still in a non-contact state in the transfer area is forcibly brought into contact with the recording paper, so that the ink adheres to the recording paper.

〔Effect of the invention〕

According to this invention, high resolution printing is possible even on paper with poor smoothness such as PPC paper. In addition, good printing can be achieved regardless of the smoothness of the recording paper. Since there are no ink transfer errors, it is possible to reproduce colors as designed, and by using inexpensive medium-quality or high-quality paper instead of high-quality paper with good smoothness, print density with even density can be achieved. You can get an expensive hard copy of.

[Embodiments of the invention]

Hereinafter, this invention will be explained in detail with reference to the drawings. Figure 1 shows one of the thermal transfer recording devices according to the present invention.
This is an example. 1 is an ink ribbon, which is a base film that serves as an ink carrier.It is solid at room temperature and becomes molten or sticky when heated.After heating, the ink temperature is lowered to below the temperature at which it melts or becomes sticky (hereinafter referred to as the tackification temperature). Remains molten or sticky even when the temperature decreases. An ink exhibiting so-called supercooling properties is applied. Inks that exhibit such properties include Tokuko Sho 46-15479 and Tokko Sho 46-15479.
There is an ink shown in 46-15480. For example, N-ethyl-P-toluenesulfonamide, glycerin ester of hydrogenated rosin, chlorinated rubber, oil block BT dye, and carbon black are mixed, heated to uniformly disperse, and recrystallized. The mixture is then used as a film-forming binder. It can be obtained by uniformly dispersing it in Substances that exhibit supercooling include acetanilide, phenacetin, benztriazole, sebacic acid, phthalic anhydride, tribenzylamine, and the like.
By selecting these substances, the tackification temperature and tackification duration can be adjusted. Furthermore, by changing the dyes, pigments, etc., inks of various colors can be created.

2 is recording paper, which can be medium-quality paper such as PPC paper, uncoated paper such as high-quality paper, or coated paper such as lightweight coated paper. 3 has a plurality of heating resistive elements 4 provided at an element density of 8 elements/mm and electrically driven by a thermal head serving as an ink heating means. A platen roller 5 presses the ink ribbon 1 and the recording paper 2 against the heating resistor element 5 in cooperation with the thermal head 3. A rubber roller with a rubber hardness of 30 to 60 degrees or a metal roller coated with a thin rubber layer is used. 6,
Reference numeral 7 denotes a pair of pressure rollers which serve as ink adhesion activation means. The pressure rollers 6 and 7 are pressed from both sides by the pressure of a compression spring 8, which is a pressure urging means that connects the ink ribbon 1 and the recording paper 2 to the pressure roller 7. It is desirable that the pressing force be as large as possible within a range that does not hinder the conveyance of the ink ribbon 1 and the recording paper 2. Also, if it is too low, the effect will not be sufficient, and 400
A pressing force of g/cm or more is desirable. The pressure roller 6 is a metal roller with a coating layer of 1 mm thick made of rubber with a hardness of 60 degrees on the surface of the metal roller.
is a metal roller. The material and diameter of the pressure rollers 6 and 7 must be designed so that they do not bend under the pressure applied by the compression spring 8. Further, the pressure contacts 6 and 7 may both be metal rollers coated with high hardness rubber, or the metal rollers may be mutually connected, or the pressure contact roller 6 may be a fixed pin.
Rubber rollers 9, 10, and 11 are ink ribbon/recording paper peeling means. The ink ribbon 1 is sandwiched between rubber rollers 10 and 11, and is forcibly changed to a direction different from that of the recording paper traveling along the rubber roller 9.

Next, the operation of this device will be explained using FIGS. 1 and 2. The ink ribbon 1 and the recording paper 2 fed out from the ink ribbon supply roll 12 and the recording paper supply roll 13, respectively, are stacked on top of each other by a guide 14 with the ink in between, and are driven at a predetermined speed by a platen roller drive motor (not shown). The thermal head 3 is supplied under the heat generating resistor element 4 along the platen roller 5 which rotates at the same speed. The ink 20 on the ink ribbon 1 is heated by the heat generated by the heating resistor element 4, which is selectively energized by the action of a thermal head drive circuit (not shown) driven by a print signal, and the ink 20 on the ink ribbon 1 is heated to exceed the tackifying temperature. Then, it melts or becomes sticky and adheres to the recording paper 2 that comes into contact with it. However, due to the unevenness of the ink receiving surface of the recording paper 2, a region A is created in which the ink 20 does not adhere to the recording paper 2, although it is heated. The ink ribbon 1 and the recording paper 2 are conveyed under pressure rollers 6 and 7, which are ink adhesion activation means, while being overlapped. At this time, the temperature of the ink in the heated portion is below the tackification temperature, but due to the supercooling nature of the ink, it maintains its melting or tackiness. By pressure rollers 6 and 7. The ink ribbon 1 and the recording paper 2 are forcibly pressed into contact with each other, so that they come into close contact with each other, and after passing the pressure rollers 6 and 7, the ink area that was not attached to the recording paper 2 is left as shown in area B. It completely adheres to the recording paper 2. After that, the ink ribbon 1 passes through rubber rollers 9 and 10, which are the peeling means for the ink ribbon 1 and the recording paper 2, and then the ink ribbon 1 is moved to an ink ribbon take-up reel that is rotated by an ink take-up reel drive motor (not shown). The direction of travel changes to the direction of . The traveling direction of the recording paper 2 is changed to the paper discharge direction by a rubber roller 16 rotated by a drive motor (not shown) and a rubber roller 17 facing the rubber roller 17 . Because the traveling directions of the two are different in this way, the ink ribbon 1
The recording paper 2 is peeled off, and the ink adhering to the recording paper 2 is transferred onto the recording paper 2.

Using this device, Beck smoothness is 50 seconds, 200 seconds,
The solid line in FIG. 3 shows the recording density when solid printing was performed using recording paper for 500 seconds and 1000 seconds under the same thermal head driving conditions. As a comparative example, pressure rollers 6 and 7, which are ink adhesion activation means,
The dashed line indicates the case where printing was performed without the above, and the dashed line indicates the case where the ink ribbon was changed to one that does not exhibit supercooling properties and an ink adhesion activation means was provided. With the configuration of the present invention, almost the same recording density is obtained regardless of the smoothness of the recording paper, but in the comparative example, as the smoothness of the recording paper decreases, the area where ink is not attached to the recording paper increases. Therefore, the recording density decreases. In the configuration of the present invention, regardless of the recording paper,
The same resolution and good image quality was obtained when recording paper with low smoothness was used as when recording paper with high smoothness was used.

FIG. 4 shows an embodiment of a serial printer constructed according to the present invention. Reference numeral 41 denotes a carriage which performs printing when moved in the direction of arrow A by a driving means (not shown). The carriage 41 has a thermal head 4 in which an ink ribbon 42, an ink ribbon supply roll 43, and heating elements of take-up rolls 4 and 24 are arranged so as to be perpendicular to the moving direction of the carriage.
5. A plate-shaped heater 46 that serves both as an ink adhesion activation means and an ink ribbon/recording paper peeling means, and a temperature sensing element 47 that detects the temperature of the plate-shaped heater are arranged. Reference numeral 48 denotes a recording sheet, which is disposed facing the heating element of the thermal head 45 and is moved in a direction perpendicular to the direction of movement of the thermal head. The thermal transfer recording process is the same as the previous explanation, so it will be omitted.
I will explain the function of 7.

The ink portion (recording portion) of the ink ribbon 42 heated by the thermal head 45 moves below the plate-shaped heater 46 without being displaced from the recording paper as the carriage moves (in the direction of arrow A). The plate-shaped heater 46 has a built-in heating element 49, and is controlled by a heater energization control circuit (not shown) to have a temperature slightly lower than the adhesive temperature of the ink. This control can be performed accurately by feeding back the output of the temperature sensing element 7 attached to the plate heater 46 to the heater energization control circuit. While passing through the plate-shaped heater 46, the ink portion that remains molten or sticky due to supercooling even after heating is kept warm by the plate-shaped heater 46 and maintained in a low viscosity or highly sticky state, and By allowing the ink to adhere to the recording paper 48 for a long time, the heated ink portion adheres to the recording paper 48 accurately.

FIG. 5 shows an embodiment of a color thermal transfer recording apparatus constructed according to the present invention. 51 is an A4 width (210mm) color ink ribbon, with yellow, magenta, cyan, and black supercooled inks running in the longitudinal direction.
It was applied repeatedly with a pitch of 300 mm.
52 is PPC paper, and 53 is an A4 line thermal head having a heat generating resistor density of 8 elements/mm, which can be brought into contact with and separated from the platen roller 55 by means of a vertical movement mechanism 54. The platen roller 55 is a metal drum whose surface is coated with rubber with a thickness of 1 mm, and the hard rubber used is a hard rubber having a hardness of 50 degrees or more. This structure provides appropriate elasticity and good thermal conductivity. 56 is a heat roller which serves both as an ink adhesion activation means and an ink ribbon/recording paper peeling means. The outer surface temperature of the heat roller 56 is detected by a temperature sensing element (not shown) provided in contact with the outer surface of the heat roller 56, and the output is detected by a heat roller temperature control circuit (not shown). ) maintains the outer surface temperature of the heat roller 56 at a temperature slightly lower than the adhesive temperature of the ink on the ink ribbon 51. Further, the heat roller 56 is pressed against the platen roll 55 by a pressure urging means (not shown), and the pressure is 400 g/cm or more. In this apparatus, ink is transferred one color at a time over the entire screen, and color recording is obtained by overlapping ink four times: yellow, magenta, cyan, and black. At this time, in order to superimpose ink on the same paper surface, after one color recording is completed, the thermal head 53 is moved away from the platen roller 55 by the vertical movement mechanism means 54, and the ink ribbon guide 57 is also moved away from the platen roller 55, and the ink is The ribbon 51 is released from the pressed state with the platen roller 55 and the thermal head 53. Thereafter, the recording paper 52 is returned to the initial position by reversing the rotational direction from the printing direction by a platen roller driving means (not shown). This device uses pressure and heat rollers to ensure that the ink adheres to the recording paper and to the previously printed ink, ensuring accurate color reproduction and producing good color even on PPC paper with poor smoothness. I was able to record.

Lamp heating can also be effectively used as an ink adhesion activation means.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a thermal transfer recording apparatus which is an embodiment of the present invention, FIG. 2 is a diagram for explaining the action of the present invention, and FIG. 3 is a diagram for showing the effect of the present invention.
FIG. 4 is a block diagram of a serial printer which is an embodiment of the present invention, and FIG. 5 is a block diagram of a color thermal transfer recording device which is an embodiment of the present invention. 1... Ink ribbon, 2... Recording paper, 3...
Thermal head, 5...Platen roller, 6,7
... Pressure roller, 8 ... Compression spring, 46 ... Plate heater, 56 ... Heat roller.

Claims (1)

[Scope of Claims] 1. A heating means that selectively generates heat based on an image signal, and a supercooling property that changes from a solid state to a sticky or molten state by heating with the heating means, and maintains said state for a predetermined period of time even after heating is stopped. A thermal transfer recording device comprising an ink carrier carrying ink, a recording medium to which ink from the ink carrier adheres, and a peeling means for peeling the ink carriers from each other,
A thermal transfer recording apparatus characterized in that an ink adhesion activation means is provided in an ink carrier conveyance path between the heating means and the peeling means. 2. The thermal transfer recording apparatus according to claim 1, wherein the ink adhesion activation means is a pressure urging means for applying pressure to the ink carrier and the recording medium. 3. The thermal transfer recording apparatus according to claim 1, wherein the ink adhesion activation means is a heating means that applies a thermal bias to at least the ink carrier at a temperature below the adhesive temperature of the ink. 4. The thermal transfer according to claim 1, wherein the ink adhesion activation means is a heat-pressure urging means that presses the ink carrier and the recording medium under a thermal bias below the tackification temperature of the ink. Recording device.