JPS60210474A - Thermal transfer type printer - Google Patents

Abstract

PURPOSE:To enhance the rate of adhesion of an ink to a recording paper and prevent bluring of the ink from occurring, by impressing a voltage between a thermal head and a platen roller which clamp a transfer paper and a recording paper therebetween, thereby performing printing. CONSTITUTION:The figure shows the case wherein a positive voltage is impressed on the side of the thermal head 3 while a negative voltage is impressed on the side of the platen roller 4. In this case, positive charges appear on the recording paper 2 side (the ink 1a side) of the transfer paper 1, and negative charges appear on the transfer paper 1 side of the recording paper 2. Therefore, since the positive charges and the negative charges attract each other, when the thermal head 3 is heated to melt or sublime the ink 1a so that the ink 1a is freed from a film 1b, the ink 1a if securely adhered onto the recording paper 2 by the attractive force between the positive charges and the negative charges.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal transfer printing device, and particularly to a printing device that performs thermal transfer printing (recording) by driving a thermal head (group).

(Prior Art) In recent years, various printing devices such as wire tod type, inkjet type, shuttle type, and thermal transfer type have been developed as computer terminal printers (hard copy devices).

Among these, it is well known that thermal transfer printing devices are widely used because they have a simpler mechanism, faster recording speed, and are easier to handle than the other printing devices mentioned above.

FIG. 1 is a diagram showing a conventional thermal transfer printing device.

In this thermal transfer printing device, first, a transfer paper (ink sheet) 1 on which a heat-melting or heat-sublimating ink 1a is applied onto a film 1b and a recording paper 2 are placed, with the ink 1a side of the transfer paper 1 facing inside. The thermal heads are stacked and brought into close contact with each other, and then sent between a thermal head group (one line of thermal heads arranged in a row) 3 and a platen roller 4 to be sandwiched therebetween.

Next, when a current is applied to the heating resistor provided in the thermal head 3 to heat it, the transfer paper 1 is heated, and the heat-melting or heat-sublimating ink 1a coated on the transfer paper 1 is melted or sublimated. and is attached to the recording paper 2.

Furthermore, if a current is caused to flow in accordance with the information signal to be printed without flowing through the heating resistor of the thermal head 3, the ink 1a of the transfer paper 1 will adhere to the recording paper 2 in accordance with the predetermined information signal, and printing will be performed. It will be done.

After each printing operation for one line, the platen roller 4 is rotated by a small angle to sequentially print (record) the next line.

In such a conventional thermal transfer printing device, for example, when the heated area of the ink 1a is small, the adhesive force of the ink 1a to the film 1b side of the transfer paper 1 is strong, so that the ink 1a is attached to the recording paper. 2, and as shown in FIG. 2(a), the area to which the adhesive should actually be attached may become smaller than the area (dotted line in the figure). In this case, a similar problem occurs even if the recording paper 2 has poor smoothness.

In addition, when overlapping printing (recording) is performed using multiple ink sheets, such as color printing, Fig. 2 (b)
As shown in the figure, when an attempt is made to print (record) the second color ink 1a2 in a wider area than the first ink 1a+ on the part where the first ink 1a+ was attached, a step is created on the recording surface (ink surface). The ink no longer adheres to the protruding part (the dotted line part in the figure) which has a larger area than the initial ink 1a+.

Furthermore, when overlapping recording is performed as described above and the second color ink 1a2 is to be recorded (printed) on the area to which the first ink 1al has been deposited in approximately the same area as the first ink 1a+, the initial Since the ink 1a+ is heated again at the same time as the second color ink 1a2 is heated,
The initial ink 1a+ had problems such as spreading (dotted line area in the figure) and smearing laterally, resulting in inaccurate printing characteristics.

(Objective of the Invention) The object of the present invention is to provide a thermal transfer printing device that solves the problems of the prior art mentioned above, improves the adhesion rate of ink to recording paper, and further prevents ink from bleeding. Our goal is to provide the following.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a transfer paper coated with heat-melting or heat-sublimable ink on a film and a recording paper on the ink side of the transfer paper. A thermal transfer type in which the ink on the transfer paper is melted or sublimated by heating the thermal head group, and the ink on the transfer paper is adhered to the recording paper to perform printing. The present invention provides a thermal transfer printing device, characterized in that the printing device is configured to perform printing by applying a voltage between the thermal head and the platen roller that sandwich the transfer paper and the recording paper. be.

(Embodiment) An embodiment of the thermal transfer printing apparatus according to the present invention will be described below with reference to the drawings. In the following figures, the same parts as those in the previous figures are given the same reference numerals, and their explanations will be omitted.

FIG. 3 is a diagram showing an embodiment of a thermal transfer printing apparatus according to the present invention.

In the figure, 1 is a transfer paper (ink sheet) on which a heat-fusible or heat-sublimable ink 1a is applied onto a film 1b, 2 is a recording paper, 3 is a thermal head, and 4 is a platen roller.

Further, on the surface of the platen roller 4, conductive rubber 5 made of a rubber material containing conductive carbon or the like is provided approximately evenly, and furthermore, an insulating rubber 6 is provided on the inner circumferential side thereof. Then, between the conductive rubber 5 and the thermal head 4, a high voltage of, for example, 500 V or more, which does not cause discharge, is applied by a high voltage power source 7.

Note that the conductive rubber 5 of the rotating platen roller 4 is connected to the high voltage power source 7 via a slip ring or the like.

FIG. 4 is an enlarged view showing the transfer paper (ink sheet) 1 and recording paper 2 sandwiched between the thermal head 3 and platen roller 4 in FIG.

This figure shows a case where a voltage of 10 is applied to the thermal head 3 side and a voltage of - is applied to the platen roller 4 side.

By doing this, the recording paper 2 side of the transfer paper 1 (the ink 1a
A charge of 10 appears on the transfer paper 1 side of the recording paper 2, and a charge of - appears on the transfer paper 1 side of the recording paper 2. Therefore, the 10 charge and the - charge attract each other, so at this time, the thermal head 3 is heated to melt or sublimate the ink 1a, and the ink 1a is heated.
If a is released from the film 1b, the ink 1
A is reliably attached to the recording paper 2 by the force of attraction between the ten charge and the negative charge.

Therefore, the problem of ink not being properly adhered as shown in FIGS. 2(a) and 2(b) is eliminated.
The ink adhesion rate improves, allowing for better printing.

In addition, as shown in FIG. 5, around one tens charge 8, there are ten charges 9.10 on the left and right and - charges 11.12 above and below.
In this case, a phenomenon is observed in which the ten charge 8 is attracted to the upper and lower negative charges 11 or 12, and is repelled from the ten charge 9.10.

This phenomenon can be summarized as shown in FIG. 6.

That is, between the transfer paper 1 and the recording paper 2, the electric field A
In the same direction as the direction of
"compressive strain force" acts in the direction perpendicular to the direction to the electric field.
stress) C” occurs.

These strain forces are called Maxwell's strain forces (References: Institute of Electrical Engineers of Japan University Course "Electromagnetics"
This shows that the dissolved or sublimated ink moves in the same direction as the electric field, but not in the direction perpendicular to the electric field.

Therefore, even if the first ink 1a+ is melted or sublimated again when the second color ink 1a2 is heated, as shown in FIG. 2(G), it will not bleed horizontally, and as shown in FIG. 2(a).
And as in the case of FIG. 2(b), good printing can be performed.

(Application example) In the embodiments of the present invention shown in FIGS. 3 to 6, even if a negative voltage is applied to the thermal head 3 side and a positive voltage is applied to the 7- platen roller 4 side, the same results will be obtained. effect can be obtained. Furthermore, it is easily conceivable that voltages of →- and -volts may be alternately applied to the thermal head side and the platen roller side, respectively, in alternating cycles.

(Effects of the Invention) Since the thermal transfer printing device of the present invention has the above-described configuration, the adhesion rate of ink to the recording paper is improved, and furthermore, ink bleeding can be prevented and good printing can be achieved. It has the advantage of being able to perform

[Brief explanation of drawings]

Figure 1 shows a conventional thermal transfer printing device, Figure 2 (a
) to (C) are diagrams for explaining the problems of conventional thermal transfer printing devices, FIG. 3 is a diagram showing an embodiment of the thermal transfer printing device according to the present invention, and FIG. An enlarged view showing the transfer paper (ink sheet) 1 and recording paper 2 sandwiched between the thermal head 3 and the platen roller 4 in the figure, and FIGS. 5 and 6 are the thermal transfer printing apparatus according to the present invention. FIG. 8- 1... Transfer paper, 1a... Ink, 1b... Film, 2... Recording paper, 3... Thermal head, 4...
・Platen 0-ra, 5... Conductive rubber, 6... Insulating rubber, 7... High voltage power supply, 8-12... Electric charge, A.
...Electric field, B...tensile strain force, C...compressive strain force. Continued from page 1 0 Inventor Shigeru Kato In-house in Yokohama City 0 Inventor Tsutomu Kiuchi In-house in Yokohama City Inventor Hiroki Kitamura In-house in Yokohama City

Claims (1)

[Claims] Transfer paper on which heat-melting or heat-sublimable ink is applied onto the film and recording paper are stacked with the ink side of the transfer paper on the inside, and these are sandwiched between a group of thermal heads and a platen roller, and the thermal head In a thermal transfer printing device that performs printing by heating a group of transfer paper to melt or sublimate ink on the transfer paper and adhere it to the recording paper, the thermal head and the platen roller that sandwich the transfer paper and the recording paper are provided. A thermal transfer printing device characterized in that it is configured to perform printing by applying a voltage between the two.