JPH01108076A - thermal transfer printer - Google Patents

Abstract

PURPOSE:To obtain an inexpensive small-type thermal transfer printer having excellent gradation recording properties and using a heat-fusible ink, by setting the feed velocities of an ink film and a recording paper at an ink-heating part to be slightly different from each other. CONSTITUTION:An ink film 3 and a recording paper 4 are fed respectively in the directions of arrows Q and P by a film-feeding means 5 and a paper- feeding means 7. The ink film 3 is given a back tension by a loading means 6, and the paper 4 is given a back tension by a platen 2 or a loading means. At a part T, an ink 3-1-a melted by heating receives shearing forces, indicated by arrows R and S, acting between a base film 3-2 and the recording paper 4. At this moment, the tack between the melted ink 3-1-a and the paper 4 is much greater than that between the ink 3-1-a and the base film 3-2, and the tack of the ink 3-1 in the vicinity of the melted ink is extremely slight, so that only the melted part of the ink is appropriately transferred.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention applies to thermal transfer printers that use heat-melting ink, and particularly to image printers that require gradation expression.

[Conventional technology]

Conventionally, the configuration of the transfer section of a thermal transfer printer using heat-melting ink has been disclosed in Japanese Patent Application Laid-open No. 105278 and Japanese Patent Application Laid-open No. 1989-1999.
68282, the ink film and recording paper are compressed by a head and a platen in an ink heating section, and the ink film and recording paper are pressed together by pressing rollers provided before and after the ink heating section, and the ink film and recording paper are wrapped around the platen. The purpose of such a suppression roller is the following two. First, a suppression roller installed in front of the ink heating section compresses the ink film and recording paper between it and the platen, and wraps the ink film and recording paper around the platen to increase the frictional force between the ink film and the recording paper, so that both It is provided to be transported at a constant speed. In addition, the suppression roller provided behind the ink heating section (in the conveying direction of the ink film and recording paper) plays the same role as the suppression roller provided in front of the ink heating section. ,1
8. When the ink that has been melted and attached to the recording paper is partially or completely solidified again after a predetermined period of time after heating, the ink film and the recording paper are separated and the ink is transferred. ing.

[Problem that the invention seeks to solve]

However, in the conventional technology described above, the ink film and the recording paper are transported at a constant speed, and when the ink has partially or completely solidified again after a predetermined period of time has elapsed, the ink film and the recording paper are transported at a constant speed. For separation, as shown in FIG. 6, when the applied energy is small and the melted part 3-1-a of the ink 3-1 is small, the VCU force between the re-solidified part 3-1-b and the recording paper 4 is The cohesive force between the coagulated portion 3-1-b and the surrounding ink 3-1 and the bone contact force between the base film 3-2 are smaller than the transfer force. Further, as shown in FIG. 7, the applied energy reaches a certain level, and the distance 3-1 between the molten part 3-1-a and the adjacent t8@part 3-1-a increases.
When 1-c becomes smaller, m Fa between parts 3-1
- From the tffiU force between c and base film 3-2,
Since the cohesive force with the surrounding ink 3-1 is large, the space between the fused parts 3-1-c is also transferred. For that reason,
When performing gradation recording by modulating applied energy, the relationship between applied energy and transfer density (or transfer area) is
There is a problem in that the value C according to the prior art shown in FIG. 5 deviates greatly from the ideal value, making it impossible to obtain beautiful gradation recording.

In addition, since not only the head but also the pressure rollers installed at the front and rear of the platen press against the platen, the alignment mechanism to make the pressing force uniform becomes complicated and requires a large number of parts (lower price, smaller size). It was becoming a negative influence.

The present invention solves the problems of the prior art,
The purpose is to provide a low-cost, small-sized thermal transfer printer that uses heat-melting ink and has excellent gradation recording performance.

[Means for solving problems]

The thermal transfer printer of the present invention is characterized in that the transport speeds of the ink film and the recording paper in the ink heating section are slightly different.

〔Example〕

FIG. 1 is a diagram showing an outline of a thermal transfer printer according to the present invention, in which 1 is a head, 2 is a platen, and an ink film 3 and a recording paper 4 are moved by film feeding means 5 and paper feeding means 7, respectively, by an arrow Q and I) at slightly different speeds, and the ink film 3 has
A buff tension is applied to the recording paper 4 by the loading means 6 via the platen 2 or a separately provided loading means (not shown).

With this configuration, the heating of the ink film 3 and the recording paper 4 and the ink transfer at the transfer portion T will be explained with reference to FIGS. 2, 3, and 4.

In the T part, since the ink film 3 and the recording paper 4 are being conveyed at slightly different speeds to the heated and melted base film 3-1-a, the shearing force indicated by the arrows R1 and S is applied to the base film 3-1-a. 2 and recording paper 4. At this time, the melted I/R 3-1-a and the base film 3-2
When comparing the adhesive force acting between the base film 3 and the EU paper 4, PET, which is generally used as the base film 3, has no permeability and has a smooth surface because it is extruded into a thin film. The recording paper 4 has many small irregularities on its surface and has high ink permeability, and as shown in FIG. The adhesive force between the melted ink 3-1-a and the molten ink 3-1-a is significantly greater than that between the molten ink 3-1-a and the surrounding ink 3-1. Because it is different, it is extremely small, and ink 3-1 is
Only the melted portion 3-1-a is properly transferred. Therefore,
Even if the melted part 3-1-a is small as shown in FIG. 2, or if the melted part 3-1-a is large as shown in FIG.
Even if 1-c is small, transfer may not occur or 3-c between the melted parts
1-c is not transferred, and in gradation recording,
The relationship between applied energy and 0 degrees of transfer is extremely close to the ideal value A, as shown in B in FIG.

〔Effect of the invention〕

As described above, according to the present invention, since the ink heating and the conveying speed of the ink film and the recording paper in the ink transfer section are slightly different, the shear force that acts between the base film and the melted ink that has adhered to the recording paper is generated. The ink is separated and transferred using a Beautiful gradation recording performance can be obtained.

Furthermore, in order to equalize the transport speed of the ink film and the recording paper, there is no need to install a pressure roller near the head platen, which requires uniform pressure teeth, making it easier to reduce the price and size of the printer. It has the effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a thermal transfer printer according to the present invention, and FIGS. Figure 5 is
Graph showing gradation recording performance according to the present invention, FIG. 6(a) (
b), FIGS. 7(a) and 7(b) are schematic % formulas showing the state of transfer in the prior art. Patent Attorney Tsutomu Mogami and 1 other person Figure 1 (Q) Figure 2 + (71 Figure 3 Figure 4 A--Kazuo Ichiori Direct B-m-Honcho 5th Hal:, 1- 2) I J (c-i, tki moxibustion book 1: ↓3 Il Figure 5 IQ+ Figure 6 Figure 7

Claims (1)

[Claims] (1) In a thermal transfer printer that presses an ink film coated with heat-melting ink onto a recording paper and transfers the heated and melted ink to the recording paper, the heating section (
A thermal transfer printer characterized in that the conveyance speed of the ink film and the conveyance speed of the recording paper in the transfer section (transfer section) are slightly different.