JPH05185634A - Hot-melt transfer type recording apparatus - Google Patents

Abstract

PURPOSE:To enhance printing quality, in a hot-melt transfer type recording apparatus, by releasing an ink sheet and recording paper in a molten state of ink to be transferred. CONSTITUTION:Function capable of imparting remaining heat to an ink sheet 4 even after printing is added to a thermal printing head 5 and the ink sheet and recording paper 2 are released immediately after they pass through a remaining heat part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fusion transfer type recording apparatus for recording an image on an image receiving paper by melting ink using a thermal print head.

[0002]

2. Description of the Related Art A printing mechanism in a conventional thermal melting transfer type recording apparatus will be described with reference to the drawings. FIG. 3 is a diagram showing an example of a printing mechanism of the type that prints on continuous paper. The image receiving paper 3 and the ink sheet 4 respectively discharged from the image receiving paper supply roll 1 and the ink sheet supply roll 2 are
Is conveyed to the printing portion so that the ink receiving surface of the ink sheet and the ink surface of the ink sheet 4 come into close contact with each other, and when passing through the portion where the thermal print head 5 and the platen 6 are in pressure contact, the printing energy is generated from the heating portion 7 according to the print signal. Receive. Even after receiving the printing energy, the image receiving paper 3 and the ink sheet 4
The image receiving paper 3 is ejected to the outside of the apparatus, and the ink sheet 4 is wound up on the roller 9 after being conveyed in close contact with the paper sheet and separated by the pinch roller 8. Here, as the thermal print head 5, a flat type thermal print head in which the heat generating portion 7 is arranged inside the end portion of the thermal print head is used.

[0003]

In the conventional mechanism as described above, it takes a long time for the ink sheet to receive the printing energy from the heat generating portion and to be peeled off from the image receiving paper. The ink melted in step 1 will be peeled off again in the solidified state. For this reason, the transferability of the ink to the image receiving paper is poor, and the printing quality cannot be improved. This problem becomes particularly noticeable when plain paper having low smoothness is used as the image receiving paper. That is, as shown in FIGS. 4 (A) and 4 (B), since the surface of the image receiving paper has fine irregularities due to fibers or the like, the ink adheres only to a part of the image receiving paper, and when the ink is solidified, the ink sheet is not formed. When the image-receiving paper is peeled off, the ink is not transferred to the recesses that do not come into contact with the ink on the surface of the image-receiving paper, and the print density cannot be increased. Also, the print dot shape, that is, the area and shape of the transferred ink differs for each print dot. This caused defects such as deterioration in image quality. Further, it is difficult to achieve gradation expression that requires precise control of the print dot shape, and the image quality of color expression is poor due to the superposition of inks of different colors. Had a problem.

[0004]

In order to solve the above problems, the present invention provides a thermal print head,
After the heat energy is applied to the ink, a residual heat function for holding the ink sheet at a temperature at which the ink does not melt is added, and a mechanism is provided for immediately separating the ink sheet and the image receiving paper from the residual heat portion.

[0005]

When the ink receives the print pulse, the temperature of the ink rises and falls according to the profile shown in FIG. Assuming that the time taken for the ink temperature to drop to the freezing point T _{C after the} temperature rise is t _C , t _C is about 100 msec. Since t >> t _{C when the} peeling time in the conventional printing mechanism is t, the ink is coagulated at the time of peeling the ink sheet and the image receiving paper, resulting in the above-mentioned deterioration of printing quality. ..

Therefore, if the thermal print head is provided with the residual heat function of the ink sheet, and the ink temperature is maintained to the extent that it does not reach the freezing point T _C even after the application of the printing energy at the heat generating portion, the ink temperature drop profile is shown in FIG. 5B. Then, the time to reach the freezing point is extended to t _{C '} . Therefore, after the printing energy is applied, the ink sheet and the image receiving paper can be peeled off in a melted state even after being conveyed for a certain distance, and the ink becomes uneven on the surface of the image receiving paper as shown in FIGS. 6 (A) and (B). The ink is transferred from the base film of the ink sheet to the image receiving paper in a familiar state, and then the ink is solidified. Therefore, the transfer amount and transfer shape of ink can be made uniform irrespective of print dots, and a high-quality image can be obtained without deterioration of print image quality due to unstable print dot shapes. Further, it becomes possible to control the area of the print dots with high accuracy, and it is possible to obtain a high-quality image such as gradation expression and color expression by ink superposition.

[0007]

EXAMPLE FIG. 1 shows an example of the present invention. The flat type thermal print head 5 has a residual heat portion 10 on the discharge side of the ink sheet 4 with respect to the heat generating portion 7, and the residual heat portion 10 is maintained at an ink melting temperature T _C or lower. The ink sheet 4 and the image receiving paper 3 receive the printing energy at the heat generating portion 7 and are then conveyed in contact with the residual heat portion 10 while being in close contact with each other. Due to the heat received from the residual heat portion, the time until the ink is solidified is extended, and the ink is in a molten state even when the portion receiving the printing energy is conveyed to the end portion 11 of the thermal print head 1. In this embodiment, the end portion 11 is used to convey the ink sheet 4 below the thermal print head 5 so that the ink sheet 4 is peeled off from the image receiving paper 3. The image receiving paper 3 can be peeled off without any trouble, and as a result, the improvement of the printing quality can be achieved as described in the section of the action.

The ink sheet and the image receiving paper are peeled off in the ink melted state immediately after passing through the heating portion by using a so-called end face type thermal print head in which a heating resistor is formed on the end face of the substrate. Can also be achieved. However, due to the structure of the end face type thermal print head, there are many problems that are difficult to solve in manufacturing in terms of film formation and pattern formation on a curved surface, heat dissipation efficiency, and the like, and it must be very expensive. In the embodiment of the present invention, the conventional flat type thermal print head has an improved structure for the thermal fusion transfer type, so that it is possible to improve the image quality while minimizing the increase in the manufacturing cost. In addition, no major change is required in the transport mechanism, and the cost increase can be suppressed from this point as well.

In order to provide the flat type thermal print head with a residual heat function after printing, for example, as shown in FIG. 2, a thin film heater 14 is added to a portion of the common electrode 12 through a protective layer 13 and is covered with a resin film 15 or the like. It is easily achieved by adopting such a structure.

[0010]

As described above, according to the present invention, the flat type thermal print head is provided with the residual heat function after printing, and the ink sheet and the image receiving paper are separated immediately after passing through the residual heat portion, so that the transfer is performed. It is possible to peel off the ink that should be melted in a molten state, and to make the shape of the print dots uniform regardless of the print dots. Due to these, the present invention can obtain a high-quality image with sufficient print density and no density variation even on an image receiving paper having low smoothness. Since it is possible to accurately control the size of the print dots, it is possible to easily achieve gradation expression and overlay color expression. This has the effect of minimizing the cost for achieving the above.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a thermal print head used in the present invention.

FIG. 3 is a schematic view showing an example of a conventional mechanism.

FIG. 4 is an explanatory diagram showing a conventional printing state.

FIG. 5 is an explanatory view of the operation of the present invention.

FIG. 6 is an explanatory diagram of a printing state of the present invention.

[Explanation of symbols]

 1 Image Receiving Paper Supply Roll 2 Ink Sheet Supply Roll 3 Image Receiving Paper 4 Ink Sheet 5 Thermal Print Head 6 Platen 7 Heat Generation Section 8 Pinch Roller 9 Roller 10 Preheated Area 11 Thermal Print Head Edge 12 Common Electrode 13 Protective Layer 14 Thin Film Heater 15 Resin film

Claims (1)

[Claims] 1. A thermal fusion transfer recording apparatus for recording using a thermal print head having a plurality of heating resistors arranged in a row, an ink sheet and an image receiving paper, wherein the thermal print head has a heating resistor. On the same surface as the main surface on which the body is formed, a residual heat heater is provided in the direction in which the ink sheet is discharged from the row in which the heat generating resistor is formed, and the ink sheet and the image receiving paper are the heat generating resistor. A thermal melting transfer type recording apparatus, characterized in that after passing through a portion where is disposed, it is peeled in contact with the surface of the residual heat heater.