JPS63267590A - Thermal transfer recording device - Google Patents

Abstract

PURPOSE:To enhance a recording density and a stability of image quality and to obtain a high reliability in carrying an image receiving paper and a thermal transfer sheet, by a method wherein a means driving the thermal transfer sheet at a fixed tension is disposed between a sheet release position and a sheet take-up reel for always setting an optimum sheet release condition. CONSTITUTION:A thermal transfer sheet 2 is separated from an image receiving paper 1 at a release position 10 of a release roller 7 and taken up by a take-up reel 6 in a direction of an arrow (a) through a sheet feed roller 11. The sheet feed roller 11 constantly rotates at a fixed torque in a direction of an arrow (a) during recording, thus imparting a fixed force T to the thermal transfer sheet 2 in pressure contact therewith due to the frictional force on the surface. The take-up reel similarly rotates at a fixed torque while varying in diameter in accordance with varying sheet take-up amount, thus imparting various tensions T1-T2 to the sheet. These forces can be set sufficiently low in comparison with the force T because the requirement is only a stable sheet carrying from the sheet feed roller 11 to the take-up reel 6. Therefore, the force at the sheet release position 10 is set to be substantially a fixed value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal transfer recording device useful as a hard copy device for outputting character images for televisions, computers, etc.

2. Description of the Related Art FIG. 3 shows a schematic configuration of a conventional thermal transfer recording apparatus. The thermal transfer sheet 2 coated with thermal transfer ink is wound around a supply reel 6, and while being unwound from the supply reel 6, it is overlapped with the image receiving paper 1 and is pressed into contact with a line-type thermal head 3 and a platen roller 4. , recording is performed by selective heating from the thermal head 3. Thereafter, the thermal transfer sheet 2 and the image receiving paper 1 are separated at the position of the peeling roller 27, the image receiving paper 1 is conveyed by the paper feed roller 8 and the paper pressing roller 9, and the thermal transfer sheet 2 is transferred to the take-up reel 6 in the direction of the arrow &. be wound up.

Here, the image-receiving paper 1 is conveyed at a constant speed by driving the paper feed roller 8 at a constant speed in the direction indicated by the arrow. Up to the peeling position 10, the sheet is conveyed together with the image receiving paper 1 because it is in close contact with the image receiving paper 1, and after passing the peeling position 10, it is conveyed by the torque of the take-up reel 6 and is wound up. ζIf the peeling conditions between the thermal transfer sheet 2 and the image-receiving paper 1 change, the ink transferability changes, causing a difference in the density and quality of the recorded image. Therefore, JP-A-61-68
As in Japanese Patent No. 279, there is an idea to adjust and control the peeling conditions. Here, the peeling conditions indicate a peeling angle, a peeling speed, and a peeling time. Ink transferability is improved by optimizing these conditions according to the transfer ink or transfer color order.

Problems to be Solved by the Invention In the conventional thermal transfer recording device, the sheet peeling position 10
The tension of the sheet that applies K was given by the rotational torque of the take-up reel 6. Since the diameter of the take-up reel 6 substantially increases as the amount of sheet taken up increases, the tensicon of the sheet decreases as the diameter increases when rotating with a constant torque. When the amount of change is large, it ranges from A to false. Moreover, if the sheet tension between the sheet peeling position 10 and the take-up reel 6 is too large,
The conveying force of the image receiving paper 1 is increased more than necessary in the portion that is in close contact with the image receiving paper 1, and even though the image receiving paper 1 is being conveyed at a constant speed by the paper feed roller 8, the thermal head 3 The receiving paper 1 is fed at a speed higher than the feed speed of the paper feed roller 8 at the pressure contact portion with the paper feed roller 8. In this case, misalignment of the recorded image, paper jams, etc. occur. Moreover, an excessively large sheet tensicon may cause damage to the sheet.

Therefore, the winding tension of the winding reel 6 cannot be made very strong at the beginning of winding, and at the end of winding, the tension becomes even more false.

Thermal transfer sheet 2. Some combinations of image-receiving papers 10 require a certain amount of sheet peeling force after recording. In that case, if the sheet tension at the sheet peeling position 1o is insufficient, the sheet will not be completely peeled off at the sheet peeling position 1o, but will peel off at another position. Therefore, the peeling conditions change and the ink transfer properties change. Therefore, the density of the recorded image 2
There will be a difference in image quality. Further, if the thermal transfer sheet 2 reaches the position of the paper feed roller 8 without being peeled off, a paper jam occurs.

Therefore, it was necessary to maintain the sheet tensicon at the sheet peeling position 1o at an optimal value, but this was very difficult with the conventional configuration.

Means for Solving the Problems In order to solve the above problems, the present invention provides means for driving the thermal transfer sheet roller with a constant tension between the sheet peeling position and the sheet take-up reel.゛Operation With the above-described configuration, the present invention improves the stability of ink transfer performance, that is, the recording density and image quality by keeping the tension at the sheet peeling position of the thermal transfer sheet at an optimum value and always optimizing the sheet peeling conditions. Furthermore, it is possible to obtain a recording apparatus in which the reliability of conveyance of the image receiving paper and the thermal transfer sheet is improved.

Embodiment Hereinafter, the configuration of an embodiment of the present invention will be explained based on the accompanying drawings.

FIG. 1 is a basic configuration diagram showing a recording apparatus in an embodiment of the present invention, in which 1 is an image receiving paper, 2 is a thermal transfer sheet, 3 is a thermal head in which a plurality of heating elements are arranged linearly, and 4
is a platen roller, 6 is a supply reel for the thermal transfer sheet 2,
6 is a take-up reel, 7 is a peeling roller that determines the peeling position 1o between the thermal transfer sheet 2 and the image receiving paper 1, and 11 is the thermal transfer sheet 2
The sheet feeding roller 12 conveys the thermal transfer sheet 2, and the sheet pressing roller 12 presses the thermal transfer sheet 2 against the sheet feeding roller 11. Reference numerals 8 and 9 denote a paper feed roller and a paper press roller for conveying the image receiving paper 1 at a constant speed.

The thermal transfer sheet 2 is overlapped with the image receiving paper 1 and pressed against the thermal head 3 and the platen row 24 to perform transfer recording. Thereafter, the image-receiving paper 1 is conveyed at a constant speed by the paper feed roller 8, and the thermal transfer sheet 2 is peeled off from the image-receiver paper 1 at the peeling position 1o of the peeling roller 7, and is transferred to the take-up reel 6 in the direction of arrow a via the sheet feed roller 11. is wound up. The sheet feed roller 11 always rotates in the direction of the arrow a with a constant torque during recording, and therefore applies a constant force (tension) T to the thermal transfer sheet 2 that is in pressure contact with it due to the frictional force on the surface. Similarly, the reel rotates with a constant torque, but its diameter changes as the amount of winding of the sheet changes, so the tension applied to the sheet is T.
, ~T2. Therefore, the tension T3 between the sheet peeling position 1o and the sheet feed roller 11 is (T+T,
) to (T+T2). Here, the tension T, ~T2 applied to the sheet by the take-up reel 6 must be sufficiently reduced relative to T, since the only condition is to ensure stable conveyance of the sheet between the sheet feed roller 11. Therefore, fluctuations in (T+T, ) to (T+T2) are reduced, and the sheet tension at the sheet peeling position 1o becomes an approximately constant value.

Now, the tension required to reliably peel off the thermal transfer sheet 2 at the sheet peeling position 1o is 2ogZa or more,
Further, it is assumed that when the amount exceeds 3 ol/CM, the image receiving paper 1 becomes misaligned on the thermal head 3. Sheet feed roller 1
The tension that drives the thermal transfer sheet on the surface of 1 is T=2
29/CM, the tension given by the take-up reel is T at the beginning of winding.

=6g/cIII At the end of the roll υ, T2 =211/aII, then the tension at the sheet peeling position 10 is T3=
27 to 24 g/cIII, which can easily satisfy the above conditions.

FIG. 2 is a basic configuration diagram showing a recording apparatus in another embodiment of the present invention. Here, the thermal transfer sheet 2 is sufficiently wrapped around the sheet feed roller 10 to generate a frictional force to drive the sheet. In this case, the configuration is simpler than the embodiment shown in FIG.

In the embodiment, the sheet peeling position 1o is located around the peeling roller rough, but the peeling position may be at the end of the thermal head 3, excluding the peeling roller 7.
Other peeling members may be provided or thermal head 3
Although this is a line type with multiple heating elements lined up, it may also be made of a single heating element.In addition, in the case of an electric thermal transfer method in which the thermal transfer sheet itself generates heat, a thermal head with heating elements lined up can be used instead. A current-carrying head may be used for this purpose, or thermal transfer recording may be performed using a laser beam or the like.

Furthermore, the image-receiving paper is transported at a constant speed by the paper feed roller, but a method may also be adopted in which the platen roller is rotated at a constant speed to convey the image-receiving paper, and the paper feed roller feeds the image-receiving paper at a constant tension.

In addition to the frictional force with the sheet, a tractor feed system in which the sheet is fed using a sprocket pin may also be used.

Effects of the Invention The present invention maintains the tension at the sheet peeling position of the thermal transfer sheet at an optimal value and always optimizes the sheet peeling conditions, thereby improving the stability of ink transferability, that is, the recording density 2 image quality, and It is possible to obtain a recording device with improved reliability in conveying the image receiving paper and the thermal transfer sheet.

[Brief explanation of drawings]

FIG. 1 is a side view showing a schematic configuration of a recording device in one embodiment of the present invention, FIG. 2 is a side view showing a schematic configuration of a recording device in another embodiment, and FIG. 3 is a schematic diagram of a conventional recording device. FIG. 3 is a side view showing the configuration. 1... Image receiving paper, 2... Thermal transfer sheet,
3...Thermal head, 6...Take-up reel, 7...Peeling roller, 11...
Sheet feed roller.

Claims (3)

[Claims] (1) A recording unit that performs thermal transfer recording by pressing the thermal transfer sheet and the image-receiving paper, a means for conveying the image-receiving paper, a winding reel that peels the thermal transfer sheet from the image-receiving paper and winds it, and a peeling position of the thermal transfer sheet. 1. A thermal transfer recording device having a regulating means, further comprising means for driving the thermal transfer sheet at a constant tension between a peeling position of the thermal transfer sheet and a sheet take-up reel. (2) The means for driving the thermal transfer sheet is composed of a sheet feeding roller that rotates with a constant torque, and the thermal transfer sheet is driven by the frictional force generated between the outer peripheral surface of the sheet feeding roller and the thermal transfer sheet in contact with it. A thermal transfer recording device according to claim 1. (3) The thermal transfer recording device according to claim 2, further comprising at least one roller that presses the thermal transfer sheet against the outer peripheral surface of the sheet feeding roller.