JPH03189183A - Inking device forthermal transfer printer - Google Patents

Abstract

PURPOSE:To transfer an ink to an ink holding body efficiently by a method wherein the cylinder of an inner roller is made eccentric to the rotation center of an inking roller. CONSTITUTION:An eccentric distance 109 between a rotation center 104c of an inking roller 104 and the center 101c of an inner roller 101 is determined so that the inner circumferential surface of the inking roller 104 is in contact with or spaced a 0.1 - 0.5 mm gap from the outer circumferential surface of the inner roller 101 at one point. An ink 103 contained in the inner roller 101 is supplied to the small gap 105 by a surface tension through an opening 106 provided on the bottom thereof, furthermore being infiltrated into the material of the inking roller 104 by the capillary phenomenon of the sintered body. The ink 103 in the small gap 105 flows inside the small gap 105 with the movement of the inking roller 104 because of its high viscosity. A change in gap distance causes a static pressure 110 to be generated. The ink 103 is forcibly filtered to the outer circumferential surface of the inking roller 104, thereafter being transferred to an ink holding body 200 by the interfacial tension.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inking device that repeatedly recycles and uses an ink carrier in a printer using a thermal transfer recording method.

[Conventional technology]

Conventionally, the basic structure of a thermal transfer recording printer capable of recording on plain paper using a thermal head is to add a heat-melting material such as a binder agent such as ester wax and a coloring agent such as a pigment to a polyester film. An ink ribbon coated with ink with a relatively low melting point is sandwiched between a thermal head, which has multiple heating resistors arranged in series, and paper, and a printing signal is applied to the thermal head while applying an appropriate pressure. The heating resistor is heated in response to the ink, melting the ink on the ink ribbon, and transferring and recording.

Further, such a thermal transfer recording method has the feature that printing can be performed not only on plain paper but also on resin-based materials such as polyester such as OHP film as a recording medium.

However, the ink ribbon has the disadvantage that it cannot be used again after the ink has been transferred to the recording medium. Furthermore, there is an uneconomical aspect in that ink remains on the ink ribbon in areas other than those that have been thermally transferred and is discarded without being used, making the use of this type of printer very expensive. There was a problem. In contrast, the ink ribbon is replaced with a heat-resistant and durable belt-shaped ink holder, ink is stored in it, the ink is transferred to the recording medium by a thermal head, and after the transfer, ink is supplied to the ink holder again. These problems will be solved by this method. Some methods for this purpose are disclosed in JP-A-62-48594 and JP-A-62-56177, both of which use an ink holder as an ink supply device by dipping an ink holder in a large ink container. ), or the rotary roller is placed in a groove and sandwiched between pressure rollers, ink is supplied to the ink holding body, and excess ink is scraped off with a knife.

However, these inking devices have a pressure roller and a knife, which places an unnecessarily large load on the ink holder when it travels, and the use of an ink container for dipping, which makes the arrangement difficult. It was impossible to apply this method to a serial printer, which required the ink supply device to be turned upside down, and this posed a major problem in the practical application of the printer.

In order to solve the problems of this ink supply device, an inking device for thermal transfer printers by the same applicant [Applicant:
July 19, 1999]. As shown in FIG. 2(a), the inking device 207 uses hot melt ink (
It is porous so that it can store 203 (hereinafter referred to as ink),
A rotatable cylindrical inking roller 204 made of a heat-resistant material, and a cylinder provided inside the inking roller 204, storing ink 203 at the bottom, and having an opening 206 at the bottom. Ink 203 is supplied between the inner cylindrical surface of the inking roller 204 and the outer cylindrical surface of the inner roller 201 by surface tension, and the ink 203 is infiltrated into the main body of the inking roller 204. A minute gap 205 is formed,
Further, a heater 202 for melting ink 203 within the internal roller 201 is connected to the internal roller 201 . Subsequently, as shown in FIG. 2(b), the molten ink 203 in the inner roller 201 is passed through the opening 206 provided at the bottom to cause the inner cylindrical surface of the inking roller 204 and the outer cylindrical surface of the inner roller 201 to be mixed. The surface tension of the ink 203 fills the small gap 205 between them, and at the same time, the ink 203 permeates from the inner cylinder surface of the inking roller 204 to the outer cylinder surface, and is guided by the guide roller 208 to the outer cylinder surface of the inking roller 204. The ink 203 is transferred to the ink holding body 200 wrapped around the ink holder 200 .

Next, FIG. 3 shows an example of the configuration of a serial printer that records one line at a time by moving a carriage including a thermal head and an inking device 207 left and right. The ink holding body 200 has a length corresponding to the height of the characters to be printed, and a length corresponding to the length that the carriage 308 can move, that is, a length corresponding to the printing range. It is fixed to mounting plates 309L and 309R provided on the carriage 308, and a plurality of guide rollers 2 are mounted on the carriage 308.
08. Furthermore, an inking device 207 that supplies ink 203 to the ink holder 200 is provided on the carriage 308 . The ink holder 200 is fixed to the mounting plate 309L on the left side of the printer, passes through the inking device 207 from the left side, and then passes through the guide roller 2.
08, the thermal head 307 and platen 30
6 and recording paper (not shown), is guided by another guide roller 208, and is attached to a mounting plate 309 on the right side of the printer.
Tension it so that it is fixed at R. By doing so,
When printing by moving the carriage 308 in the direction of arrow A, the ink holding body 200 is fixed, but after printing, the thermal head 307 is retracted backward and the carriage 30
8 in the direction of arrow B, the ink holder 200
The recorded portion is again supplied with ink by the inking device 207 of the carriage 308 passing from the opposite side. Then, when performing the next recording operation, the ink holder 2
The ink on 00 is solidified, making it possible to record again and to use it repeatedly.

[Problem to be solved by the invention]

However, in the inking apparatus shown in FIGS. 2(a) and 2(b), the heat-melting ink 203 used is
has a viscosity of 150 to 750 cp (centipoise) when melted.
The inking roller 20 is tall and made of porous material.
The pressure loss when the ink 203 passes through the inking roller 204 is very large, and it is difficult to quickly penetrate the ink 203 to the outer peripheral surface of the inking roller 204 using only the penetrating force due to surface tension. Therefore, if a serial printer using this device prints continuously for a long time, it will eventually become impossible to uniformly apply the ink 203 to the ink holder 200.
As a result, a problem has arisen in that the recording density gradually decreases.

An object of the present invention is to provide an inking device for a thermal transfer printer that solves these problems.

[Means to solve the problem]

The inking device for a thermal transfer printer according to the present invention includes a rotatable cylindrical inking roller formed of a porous heat-resistant material that stores heat-melting ink, and a rotatable cylindrical inking roller provided inside the inking roller. The inking roller includes a cylindrical internal roller that stores heat-fusible ink and has an opening at its bottom, and a heater that is connected to the internal roller and melts the hot-fusible ink. A thermal transfer printer, wherein a minute gap is formed between an inner cylindrical surface and an outer cylindrical surface of the inner roller to supply the thermofusible ink by surface tension and allow the thermofusible ink to penetrate into the inking roller body. In the inking device, the cylindrical center of the internal roller is eccentric with respect to the rotation center of the inking roller.

[For production]

According to the present invention, ink is poured into the inner roller of the inking device in advance, and the molten ink is passed through the opening at the bottom to fill the minute gap between the inner cylindrical surface of the inking roller and the outer cylindrical surface of the inner roller. During recording, the pressure increases as the ink swirls and flows through a minute gap that changes from wide to narrow due to the eccentricity of the internal roller. , the ink is forcibly filtered from the inner cylindrical surface of the inking roller to the outer cylindrical surface, and transferred to an ink holder wound around the outer cylindrical surface of the inking roller.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a side sectional view showing an embodiment of the inking device of the present invention. The internal roller 101 is constantly set at a temperature of 80 to 150° C. by a connected heater 102, and is heated with heat-melting ink (hereinafter referred to as ink) 10.
3 is melted and stored at the bottom. Then, on the outside of the inner roller 101, a rotatable cylindrical inking roller is formed of a sintered metal that is a collection of countless capillary tubes connected to each other by sintering metal powder, for example. 104 is provided and heated by the heater 102. A minute gap of several mm or less is formed between the inner peripheral surface of the inking roller 104 and the outer peripheral surface of the inner roller 101.

FIG. 1(b) is a top sectional view of FIG. 1(a).

In FIG. 1(b), the rotation center 104c of the inking roller 104 and the center 101c of the internal roller 101 are
The inner circumferential surface of the inking roller 104 and the outer circumferential surface of the inner roller 101 are in contact at one place or 0.1 to 0.5 m
The eccentric distance 109 is set to create a gap of m. Next, the ink 103 stored in the internal roller 101 is supplied to the minute gap 105 through the opening 106 provided at the bottom of the inner roller 101 by surface tension, and the ink is The roller 104 also has the inking roller 1 due to the capillary action of the sintered body.
It is penetrated into the inside of the material of 04. That is, the inking roller 104 itself contains the ink 103. Then, the guide roller 108 moves the ink holder 200 so that the recording surface of the ink holder 200 and the outer peripheral surface of the inking roller 104 come into contact with each other for a predetermined length.
0 is wound around the inking roller 104 and the ink holding body 200 is run, the inking roller 104 rotates.

FIG. 1(C) is a diagram showing the generation of static pressure on the internal roller. In FIG. 1(C), the ink 103 in the minute gap 105 has a high viscosity, so it flows in the minute gap 105 together with the inking roller 104, and static pressure 110 is generated due to the change in the gap distance, and the ink 10B is forced to The ink is then filtered onto the outer peripheral surface of the inking roller 104. Then, the filtered ink 103 is transferred to the ink holder 20 due to its interfacial tension.
Transferred to 0. As a result, even if a serial printer using this device performs continuous recording for a long time, the ink holder 2
The diameter of the inking roller 104 can be adjusted so that the ink 103 can always be uniformly applied to the ink holder 200 without any decrease in recording density. By setting a large value, the contact time can be increased, and the traveling speed of the ink holder 200 can be increased, that is, the recording speed can be increased.

It should be noted that the description of this embodiment does not describe the limitations of the embodiment depending on the recording format of the printer, such as a serial printer or a line printer, and it is clear that the purpose of the present invention can be achieved with any recording format. .

〔Effect of the invention〕

As described above, the inking device described above solves the problems of economic efficiency, recording speed and recording density changes of conventional thermal transfer printers, efficiently transfers ink to the ink carrier, and achieves economical efficiency that can be recycled. A printer capable of high-speed recording with high speed can be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a side sectional view showing one embodiment of the present invention, FIG. 1(b) is a top sectional view of the same figure (a>), and FIG. 1(C) is the generation of static pressure on the internal roller. FIG. 2(a) is a side sectional view showing a conventional example, FIG. 2(b) is a top sectional view of FIG. 2(a), and FIG. 3 is a configuration of a thermal transfer printer using an inking device. It is a partial top view showing 101...inner roller, 103... ink, 104
... Inking roller, 105 ... Minute gap, 10
7... Inking device, 108... Guide roller,
109... Eccentric distance, 110... Static pressure, 200...
...Ink holder.

Claims (1)

[Claims] a rotatable cylindrical inking roller formed of a porous heat-resistant material for storing heat-melting ink; a cylindrical inner roller having an opening at the inner roller; and a heater connected to the inner roller for melting the heat-fusible ink, the inner cylindrical surface of the inking roller and the outer cylindrical surface of the inner roller. supplying the hot-melt ink by surface tension between
In the inking device for a thermal transfer printer in which a minute gap is formed in the inking roller body to allow the hot-melt ink to penetrate, the cylindrical center of the inner roller is eccentric with respect to the rotation center of the inking roller. Features of inking device for thermal transfer printers.