JPS61263778A - Thermal transfer recorder - Google Patents

Abstract

PURPOSE:To obtain a desired transfer recorded density and constant image quality, by a method wherein a thermal transfer recording sheet provide with a thermal transfer layer comprising assistant particles for ink transfer mixed in an ink material and a recording medium are released from each other by heating to a certain extent even after transfer recording. CONSTITUTION:By thermal energy supplied from the lower side of a base 110, a binder material contained in an ink material 121 of a transfer sheet 100 is melted and liquefied, with the result of a lowering of viscosity. Melting of the binder material spreads from the vicinity of high melting point assistant articles 122 contained in the binder material. After the binder material is adhered to the surface of the recording medium 200, heat is deprived of by the medium 200, whereby the viscosity of the binder material is increased, and the binder materials is hardened. After heating of the base 110 is completed and while the ink material 121 not making contact with the medium 200 is not solidified by cooling but is in a fluid state, the medium 200 and the transfer sheet 100 are released from each other, whereby the melted ink material 130 in the state of being adhered to the surfaces of the particles 122 is transferred onto the surface of the medium 200 together with the particles 122. Accordingly, the amount of the ink material is stabilized, and gradation recording with high image quality can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal transfer recording apparatus that thermally transfers and records monochromatic gradation images, color images, etc. on a recording medium in continuous gradation using a thermal head.

Conventional technology A conventional thermal transfer recording device creates a thermal transferable ink layer on the surface of a heat-resistant base sheet such as capacitor paper or polyethylene terephthalate (PICT) film by mixing a pigment coloring material with a binder material such as hot melt wax. Using a so-called melt transfer type thermal transfer recording sheet formed with
With the recording medium and the thermal transfer recording sheet in pressure contact, the temperature is selectively increased and recorded by the thermal recording head from the side of the base sheet on which the ink layer is not formed, that is, the back side of the base sheet, and as the binder material melts. This substantial reduction in the viscosity of the ink material has been used to transfer and adhere the ink to the recording medium (for example, Japanese Patent Publication No. 49-26245).

In that case, by providing a section in which the recording medium and the thermal transfer recording sheet run in close contact with each other until the thermal transfer recording sheet is peeled off from the recording medium after recording, or by further providing a sheet cooling means in that section, the average image You can obtain recorded images with high density and excellent image quality (
For example, Japanese Patent Application Laid-open No. 100172/1983).

In addition, as a structure of the thermal transfer layer, a thermal transfer recording sheet containing ink transfer auxiliary particles having a melting point or pouring point higher than that of the binder material and at least a part of which has a particle size larger than the thickness of the ink material is used. There is a device that records on a recording medium in continuous gradation (for example, Technical Report IPD92-6 of the Television Society of Japan).

Problems to be Solved by the Invention As described above, in a thermal transfer recording device using a thermal transfer sheet mixed with ink transfer auxiliary particles, the time required to peel off the thermal transfer recording sheet from the recording medium after recording or the cooling conditions have a large effect on image quality. It turned out to have an impact. In this case, if a long section is provided in which the recording medium and the thermal transfer recording sheet run in close contact with each other as in the past, the transferred ink material cools down and returns to its original solid form, making it difficult to pull the thermal transfer recording sheet off. Occasionally, uneven peeling occurs and image quality deteriorates.

The present invention has been made in view of the above, and an object of the present invention is to provide a thermal transfer recording device that can consistently obtain the desired transfer recording density and image quality using a thermal transfer sheet mixed with ink transfer auxiliary particles. It is said that

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has an ink material whose viscosity is controlled to be reduced by temperature increase recording control and is imparted transferability to a recording medium, and this ink Adding ink transfer auxiliary particles to the ink material, which have a melting point or pour point higher than that of the binder material, which is a constituent component of the material, and at least a part of which has a particle size greater than or equal to the thickness of the layer made of the ink material. A thermal transfer recording sheet, in which the mixed thermal transfer layer is placed on one side of a sheet-like heat-resistant substrate, and the recording medium are heated to some extent after transfer recording and then peeled off, resulting in stable high-quality images. It is possible to record the key.

Function The present invention is provided with a means for heating the transfer sheet after recording and before peeling the recording medium from the transfer paper, so that the transfer sheet and the recording medium can be peeled off while maintaining the temperature at which the ink material does not cool or solidify. The amount of ink material transferred is stable, and high-quality gradation recording can be performed.

Embodiment FIG. 1 is a block diagram of a thermal transfer recording apparatus in an embodiment of the present invention. 610 is a line type thermal head, and heating elements 620 are arranged at a density of, for example, 4 dots/mn+. The recording medium 200 and the transfer sheet 100 are sandwiched between the heating element 620 and the platen 610, and the platen 61
By rotation like arrow 611 of 0, arrows 612, 61
Feed the paper as shown in step 3. The heat generation of the heating element 520 is controlled by an electric signal given to the heating element 520, and the transfer sheet) 1
The ink material 121 on the recording medium 200 is melted and transferred to the surface of the recording medium 200 to form an image. Here, the heating element 52
A heating member 700 is provided behind the transfer sheet 100 at a position in contact with the back surface of the transfer sheet 100. The heating member 700 is configured by raising a part of the surface of the substrate of the thermal head 510 or adhering another member, so that the heat transmitted from the heating element 520 can be used to heat the surface of the thermal head 5100 to some extent during recording. The heating element 620 may be heated independently of the heating element 620 by another heat source. In either case, if the ink material 121 on the transfer sheet 100 is heated to a temperature higher than the melting point or pour point of the binder material contained therein, the recording characteristics will be affected, so it is necessary to maintain the ink material 121 at a temperature lower than that temperature. It is also possible to use sensors, etc. to control the temperature in order to maintain the same temperature.

At distance L1 from heating recording to tearing off,
Since the transfer sheet 1oO is in contact with the heating member 700, the ink material 121 is not easily cooled and is peeled off while maintaining its fluidity, so that high-quality recording can be performed.

FIG. 2 is a configuration diagram of a thermal transfer recording apparatus in another embodiment of the present invention. Reference numeral 530 denotes an end face thermal head having a plurality of heating elements 540 linearly arranged on the end face of a plate-like substrate having a substantially rectangular cross section. A recording medium 200 and a transfer sheet 1oO are sandwiched between a heating element 540 and a platen 610, and the paper is fed as shown by arrows 612 and 613 by rotation of the platen 610 as shown by an arrow 611. Here, a heating member 710 is provided behind the heating element 620 at a position in contact with the back surface of the transfer sheet 100. The heating member 710 also serves as a heat radiating plate for the purpose of radiating heat from the thermal head 530, and is designed to maintain a certain temperature during recording by the heat transmitted from the heating element 540. At distance L2 from heating recording to peeling off, the transfer sheet 100
is in contact with the heating member 710, so the ink material 121
The film is less likely to cool down and is peeled off while retaining its fluidity, making it possible to record high-quality images.

In this embodiment, a line type thermal head is used, and the thermal head equipped with a small number of heating elements is slid on a transfer sheet in a direction perpendicular to the feeding direction of the recording medium. The same applies to the configuration of a serial printer.

FIG. 3 is a diagram showing the principle of transfer recording using a thermal transfer sheet mixed with ink transfer auxiliary particles.

1oO is a thermal transfer recording sheet (hereinafter referred to as a transfer sheet), and 2oO is a recording medium. Transfer sheet 100
The binder material contained in the ink material 121 of the transfer sheet 1oo is melted and liquefied by the heat energy applied from the lower surface of the base 110, and the viscosity is reduced. On the other hand, if a material with a higher melting point or pouring point than the binder material is selected as the auxiliary particles 122, heat conduction from the auxiliary particles 122 to the binder material progresses, so that the melting of the binder material spreads from around the auxiliary particles 122. After the binder material on the surface of the auxiliary particles 122 adheres to the surface of the recording medium 2000, heat is removed by the recording medium 200, the viscosity increases, and further solidification occurs. After the heating from the bottom surface of the substrate 11o is completed, before the ink material 121 that does not contact the recording medium 200 cools down and returns to a solidified state, that is, while it is still in a fluid state, the recording medium 200 and the transfer sheet 100 are
When the ink material 130 is peeled off, the melted ink material 130 adheres to the surface of the auxiliary particles 122 and is transferred to the surface of the recording medium 200 together with the auxiliary particles 122 .

Therefore, the amount of ink material 130 transferred can be controlled by thermal energy. However, the recording medium 20
When the recording medium 200 and the transfer sheet 10o are separated after the ink material 121 that does not come into contact with the ink material 121 cools and solidifies,
The solidified ink material 131 is transferred onto the surface of the recording medium 200 without being limited to the area where it is melted by heating. Therefore, the transferred ink material 131 is
In some cases, a wider area around the auxiliary particles 122 is transferred, and in other cases, even if the particles are on the surface of the auxiliary particles 122 and are not transferred to the recording medium 2,
In some cases, only the portion that was in contact with 00 is transferred. Therefore, the appearance of the transferred ink material 131 cannot be controlled by thermal energy. The image quality deteriorates due to uneven recording density in units of a small area. Due to the configuration of the recording apparatus, there is a section where the recording medium 200 and the transfer sheet 100 run in contact even after recording, so cooling of the ink during that period is unavoidable. Therefore, a means is provided to heat the transfer sheet after recording and before it is peeled off, so that the ink material 130
The ink material 130 is transferred by running the ink material 130 to a peeling position while cooling and keeping it at a temperature where it does not solidify.
The amount of gradation is stable, and high-quality gradation recording can be performed. Further, since the ink material 130 is kept in contact with the recording medium 200 for a long time while maintaining its fluidity, a sufficient amount of the melted ink material 130 adheres to the recording medium or seeps into the recording medium after heating recording. Therefore, transfer recording is performed with higher efficiency with respect to the energy used for recording and heating after recording.

Effects of the Invention With the above configuration, the present invention expands the melted part of the ink material according to the amount of heat applied to the ink material from the thermal head, and after being transferred to the surface of the recording medium, the ink material is in a state where it is not solidified. Since the recording medium and transfer sheet are separated, a good halftone image can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a thermal transfer recording device according to an embodiment of the present invention, FIG. 2 is a block diagram of a thermal transfer recording device according to another embodiment of the present invention, and FIGS. 3 a and b are diagrams of a thermal transfer recording sheet according to the present invention. FIG. 2 is a diagram of the transfer principle. 1oO...Transfer sheet, 1qo...Thermal transfer layer, 121...Ink material, 122...
... Auxiliary particles, 200 ... Recording medium, 510
...Thermal head, 610...Platen Fig. 2

Claims (3)

[Claims] (1) It has a recording medium and an ink material whose viscosity is controlled to be reduced by temperature-raising recording control and imparts transferability to the recording medium, and has a melting point higher than that of the binder material that is a component of the ink material. A thermal transfer layer in which the ink material is mixed with ink transfer auxiliary particles having a pour point and at least a part of which has a particle size larger than the thickness of the layer made of the ink material is coated in a sheet-like form. A thermal transfer recording sheet installed on one side of a heat-resistant substrate, a platen, and a thermal head equipped with one or more heating elements, and the recording medium and the thermal transfer recording sheet are connected to the platen and the thermal head. A thermal transfer recording apparatus comprising a means for heating the thermal transfer recording sheet during a period after the recording is performed by nipping and pressing the thermal transfer recording sheet with a head and until the thermal transfer recording sheet is peeled off from the recording medium. (2) The thermal transfer recording apparatus according to claim 1, wherein the thermal transfer recording sheet is heated by the heat of the substrate near the heating element of the thermal head. (3) The thermal transfer recording apparatus according to claim 1, wherein the thermal transfer recording sheet is heated by heat from a heat sink of a thermal head.