JPH0414480A - Light heat converting type recording method and recording device - Google Patents

Abstract

PURPOSE:To prevent a recording head from deteriorating and make speed-up of recording and free setting of picture element number or resolution possible by a method wherein on a light permeable hollow cylindrical shaped base, at least a transparent conductive layer, light conductive layer and electric conductive layer are laminated in this order, and between the transparent conductive layer and electric conductive layer, a rotatable heating drum to which voltage is added is used as a recording element. CONSTITUTION:When a light L is cast upon a light conductive layer 3 through a light permeable hollow cylindrical shaped base 1 and transparent conductive layer 2, the cast part (diagonally lined part) shows conductivity and a resistance value decreases. Since the transparent conductive layer 2 and an electric conductive layer 4 are connected to a power source 6, Joule heat is generated. When the casting of the light is stopped, the light conductive layer 3 begins to have insulating property and electric current stops running, and Joule heating stops generating. Therefore, by bringing a heat-sensitive recording material such as a heat- sensitive coloring material, heat-sensitive molten transfer material or heat-sensitive sublimation transfer material, etc. into linear-contact with the electric conductive layer 4 to be pressure- bonded, and carrying a recording material while synchronizing with the rotation of a heating drum 5, and at the same time, controlling the light casting to the light conductive layer 3 in response to image information, an optional image recording can be performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photothermal conversion type recording method and recording device in which light is irradiated to make it conductive, energize it and generate heat, and convert it into heat for recording. It is something.

[Conventional technology]

BACKGROUND ART Conventionally, there are widely used thermal recording methods in which a thermal head is used as a heating element and recording is performed using a thermal color recording material, a thermal melt transfer recording material, or a thermal sublimation transfer recording material.

In thermosensitive color recording, for example, a coloring layer in which fine particles of leuco dye and color developer are dispersed in a binder is formed on cellulose fiber paper,
Heat-sensitive coloring paper provided on a base material such as synthetic paper is used as recording paper, and it is held between the thermal head and the platen roller so that the surface of the coloring layer of the heat-sensitive coloring paper is in contact with the thermal head. Recording is performed by coloring heat-sensitive coloring paper, and recording is performed continuously by conveying the heat-sensitive coloring paper by rotation of a platen roller.

Heat-sensitive melt transfer recording uses a heat-sensitive transfer film with a coloring material layer mainly made of pigment and wax on one side of a base material such as polyester film, and recording paper such as cellulose fiber paper, synthetic paper, or plastic film. A thermal head and a platen roller press the color material layer of the heat-sensitive transfer film and the recording paper, and the heat generated by the thermal head melts the color material layer of the heat-sensitive transfer film and transfers it to the recording paper. , recording is performed continuously by transporting the thermal transfer film and the recording paper.

Heat-sensitive sublimation transfer recording uses a heat-sensitive transfer film with a dye layer consisting of a sublimable dye and a binder on one side of a base material such as a polyester film, and a base material such as cellulose fiber paper, synthetic paper, or plastic film. An image receiving paper with a receiving layer is used, and the dye layer of the thermal transfer film and the receiving layer of the image receiving paper are pressed together with a thermal head and a platen roller so that they are in contact with each other, and the dye layer of the thermal transfer film sublimates due to the heat generated by the thermal head. The image is then transferred onto image-receiving paper, and recording is performed continuously by conveying the thermal transfer film and the image-receiving paper.

In addition, conductive layers are formed on both sides of a flat photoconductive layer, and a voltage is applied between both conductive layers to expose the photoconductive layer. This takes advantage of the fact that current flows through the photoconductive layer in the light-irradiated area and generates heat. A flat photothermal conversion type thermal recording device has also been proposed, in which a thermal recording paper is pressed into contact with the thermal recording device.
No. 47561 and Japanese Unexamined Patent Publication No. 64-11849 [Problems to be Solved by the Invention] However, thermal recording using a thermal head and a thermal recording material has the following problems.

■Thermal coloring paper and thermal transfer film are conveyed while being in pressure contact between the thermal head and the platen roller, so the thermal coloring paper and thermal transfer film are subjected to friction between the thermal head and the thermal head under heating conditions. Large mechanical load.

As a result, there are problems such as wrinkles appearing on the thermal coloring paper and thermal transfer film during printing, and residues scraped from the thermal coloring paper and thermal transfer film adhering to the thermal head, resulting in deterioration of printing quality. Easy to occur.

(2) If the recording speed is increased, heat will accumulate in the thermal head and the recording density will change, so there is a limit to how much recording time can be shortened, and it is difficult to increase the recording speed.

(2) Since the number of pixels and resolution of a recorded object are determined by the number and density of heating elements of the thermal head, it is not possible to perform recording with different numbers of recording pixels and resolutions using the same thermal head.

In addition, in flat photothermal conversion type thermal recording devices, when the recording area is increased, it is difficult to uniformly contact the conductive layer of the flat recording device and the thermal recording material, resulting in uneven printing and poor print quality. In addition, the mechanism for ensuring uniform contact between the conductive layer and the recording paper and the paper feeding mechanism become complicated, resulting in an increase in the size of the apparatus.

Furthermore, when a laser beam is used as a light source, there is a problem in that the mechanism becomes complicated because the beam needs to be scanned two-dimensionally.

The present invention is intended to solve the above-mentioned problems, and it is possible to freely set the number of pixels and resolution without causing wear or heat accumulation of the recording head, and to easily equalize the contact between the recording head and the recording paper. It is an object of the present invention to provide a photothermal conversion type recording method and a recording device that can simplify the device.

[Means to solve the problem]

The present invention provides a recording element comprising a rotatable heating drum in which at least a transparent conductive layer, a photoconductive layer, and a conductive layer are laminated in this order on a light-transmitting hollow cylindrical substrate, and a voltage is applied between the transparent conductive layer and the conductive layer. It is characterized by being used as

[Effect]

In the present invention, when image exposure is performed from inside a light-transmitting hollow cylinder,
Light is irradiated onto the photoconductive layer through the hollow cylindrical base material and the transparent conductive layer, and the exposed portion of the photoconductive layer becomes conductive, causing a current to flow between the transparent conductive layer and the conductive layer, generating heat in the photoconductive layer.
By transmitting this heat to the recording material through the conductive layer, light can be converted into heat and recorded.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

FIGS. 1 and 2 are diagrams for explaining the thermal recording principle of the present invention. In the figure, 1 is a light-transmitting hollow cylindrical base material, 2 is a transparent conductive layer, 3 is a photoconductive layer, 4 is a conductive layer, and 5 is a heat generating drum.

As shown in FIG. 1, the heating drum 5 is constructed by laminating a transparent conductive layer 2, a photoconductive layer 3, and a conductive layer 4 on a light-transmissive hollow cylindrical base material 1, and the heating drum 5 is constructed by laminating a transparent conductive layer 2, a photoconductive layer 3, and a conductive layer 4 on a light-transmissive hollow cylindrical base material 1. During recording, the recording material is rotated in the same direction as the conveyance direction of the heat-sensitive recording material.

The light-transmitting hollow cylindrical base material l has a transparent conductive layer 2 and a photoconductive layer 3.
, has a function of supporting the conductive layer 4 and transmitting light irradiated from the inside of the heat generating drum 5 by an exposure means (not shown) to reach the photoconductive layer 3 . Transparent conductive layer 2
is for transmitting light from the exposure means and is connected to the power source 6 to apply a voltage between it and the conductive layer 4, and may be made of, for example, an indium-tin oxide thin film. The photoconductive layer 3 is made of a material whose electrical resistance decreases when exposed to light, such as selenium or amorphous silicon. As the material constituting the photoconductive layer 3, a wide variety of conventionally known photoconductive materials used in electrophotographic photoreceptors, photodiodes, and phototransistors can be used. The conductive layer 4 is used to apply a voltage between it and the transparent conductive layer 2, and also transmits the Joule heat generated in the light-exposed portion of the photoconductive layer 3 to the heat-sensitive recording material pressed against the conductive layer 4. A wide variety of conventionally known good conductors can be used. Note that the conductive layer 4 needs to efficiently transmit the heat generated in the photoconductive layer to the recording material, so the conductive layer 4 has a thickness of several microns in order to reduce its heat capacity.
It is preferable to set the thickness to approximately 100 m. In addition, the transparent conductive layer 2
and photoconductive layer 3 and/or between photoconductive layer 3 and conductive layer 4
If necessary, a resistance layer may be provided between the two to generate heat.

The heating drum 5 having such a structure selectively generates heat only in the portions irradiated with light from an exposure means (not shown). This selective heat generation process will be explained with reference to FIG.

When the photoconductive layer 3 is irradiated with light through the light-transmitting hollow cylindrical substrate 1 and the transparent conductive layer 2, the irradiated area (the shaded area in FIG. 2) exhibits conductivity and its resistance value decreases. Photoconductive layer 3
The transparent conductive layer 2 and the conductive layer 4, which are provided on both sides of the photoconductive layer 2, are connected to a power source 6 and a voltage is applied to them, so when the resistance value of the photoconductive layer 3 decreases, a current flows in the thickness direction and Joule heat is generated. Occur. Next, when the light irradiation is stopped, the photoconductive layer 3 becomes insulating and no current flows (and no Joule heat generation occurs). In other words, the same operation as a thermal head can be performed.

Therefore, the conductive layer 4 includes a heat-sensitive coloring material, a heat-sensitive melt transfer material,
Alternatively, a heat-sensitive recording material such as a heat-sensitive sublimation transfer material is brought into line contact and pressure-contacted, and the recording material is conveyed in accordance with the rotation of the heat-generating drum 5, and the photoconductive layer 3 is conveyed in accordance with the image information.
Any desired image recording can be performed by controlling the light irradiation.

Exposure means used in the present invention include (1) a combination of a laser light source such as a semiconductor laser, an Ar laser, or a He-Ne laser, a modulation means, and a scanning means;
Exposure heads in which light emitting elements such as LEDs and plasma light emitting cells are arranged in one or two dimensions, ■ combinations of liquid crystal arrays in which liquid crystal cells with a shutter function are arranged in one or two dimensions, and light sources; A combination of a negative original, a light source, and an optical system that images transmitted light or reflected light from the negative original onto a conductive layer can be used, but the present invention is not particularly limited thereto.

FIG. 3 is a diagram showing an embodiment of the present invention using a thermosensitive coloring material. In the figure, the same numbers as in FIGS. 1 and 2 indicate the same contents, 7 is a platen roller, 8 is a guide. Laura, 9
is a thermosensitive coloring paper.

In this embodiment, the heat-sensitive coloring paper 9 is continuously conveyed by a guide roller 9 in accordance with the rotational speed of the heat generating drum, and is pressed against the heat generating tram 5 by a platen roller 7 so as to be in line contact with the heat generating tram 5. On the other hand, one-dimensional exposure means (not shown) provided in the drum
When exposed to light, the portion of the photoconductive layer 3 irradiated with the light generates heat as described above, whereby the thermosensitive coloring paper 9 develops color and recording can be performed. In this case, by keeping the rotational speed of the heating drum and the conveying speed of the heat-sensitive recording material the same, friction will not occur between the drum and the heat-sensitive recording material. In addition, the heating drum is cylindrical and rotates, and the same part only generates heat after one rotation, so it is sufficiently cooled during that time, so even if the printing speed is increased, there will be no thermal or rad damage, as seen with RAD. There is no effect of heat storage. In addition,
By increasing the width of the contact line between the conductive layer and the recording material and selecting the appropriate exposure means, it is possible to simultaneously record multiple lines and increase the speed of printing.

Furthermore, if the opposite side of the heat generating drum is exposed in the same way, recording can be performed on both sides, and recording efficiency can be improved. However, in this case, the recording material is transported in opposite directions on both sides.

Further, linear pressure is applied to the portion of the heat-sensitive drum in contact with the recording material, and the contact state can be easily made uniform.

FIG. 4 is a diagram showing another embodiment of the present invention using a heat-sensitive melt transfer material. In the figure, IO is a thermal transfer film, 11
is recording paper.

This example uses a heat-sensitive melt transfer material as the recording material, and when a portion of the photoconductive layer 3 generates heat due to light irradiation,
The melt transfer layer (wax) of the heat-sensitive transfer film is melted and transferred to the recording paper 11 when the amount of heat applied is greater than a predetermined value. Note that if the amount of heat applied is less than a predetermined value, the image will not be transferred and will be binarized and recorded dot by dot. The gradation is expressed by the ratio of the number of recorded dots to the number of dots constituting one pixel.

FIG. 5 is a diagram showing another embodiment of the present invention using a heat-sensitive sublimation transfer material. In the figure, 12 is a thermal transfer film, 13
is the receiving paper.

This example uses a heat-sensitive sublimation transfer material as the recording material, and when the photoconductive layer 3 generates heat due to light irradiation,
The sublimation transfer dye in the sublimation transfer layer of the heat-sensitive transfer film is sublimated by heating, and is attached to and dyed on the image-receiving paper. In this case, since the sublimation transfer dye is vaporized by the amount of heat applied and transferred to the image receiving paper, a gradation corresponding to the amount of heat is recorded for each pixel dot.

〔Effect of the invention〕

As described above, according to the present invention, there is no friction with the heat-sensitive recording material compared to the conventional thermal head, so the thermomechanical load on the material is significantly reduced, and the occurrence of wrinkles during printing and on the head. It is possible to prevent deterioration of printing quality due to the adhesion of residue.

In addition, since the heating drum is cylindrical and rotates, the same part does not generate heat repeatedly, so even if the printing speed is increased, there is no effect of heat accumulation like that seen with thermal heads.
By selecting the exposure means, it is possible to record multiple lines at the same time, thereby increasing the speed of printing.

In addition, since linear pressure is applied to the part of the thermal drum that contacts the recording material, the contact condition is uniform and good, which greatly improves printing quality compared to flat photothermal conversion recording. In addition, the device can be made more compact.

Furthermore, by appropriately selecting the exposure means, the same heat-generating drum can be used for recording at various resolutions.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams for explaining the heat-sensitive recording principle of the present invention, Figure 3 is a diagram showing an embodiment of the present invention using a heat-sensitive coloring material, and Figure 4 is a diagram showing an embodiment of the present invention using a heat-sensitive melt transfer material. FIG. 5 is a diagram showing another example of the present invention using a heat-sensitive sublimation transfer material. l...Light-transparent hollow cylindrical base material, 2...Transparent conductive layer,
3... Photoconductive layer, 4... Conductive layer, 5... Heat generating drum, 7... Platen roller, 8... Guide roller,
9...Thermal coloring paper, 10...Thermal transfer film, 1
1... Recording paper, 12... Thermal transfer film, 13.
...Receiving paper. Applicant Dai Nippon Printing Co., Ltd. Agent Patent Attorney Masanobu Hirukawa (7 others) Figure 6, Source 2 Figure 87 Fuitlow 7 9, Kinnetsuharu Shikishi

Claims (2)

[Claims] (1) A hollow cylindrical rotatable heating drum in which at least a transparent conductive layer, a photoconductive layer, and a conductive layer are laminated in this order on a light-transmissive hollow cylindrical substrate, and a voltage is applied between the transparent conductive layer and the conductive layer. Photothermal conversion is characterized by irradiating light from inside, making the photoconductive layer conductive, energizing it and generating heat, pressing the recording material against a heat-generating drum, conveying it at the rotational speed of the heat-generating drum, and recording. Type recording method. (2) At least a transparent conductive layer, a photoconductive layer, and a conductive layer are laminated in this order on a light-transmissive hollow cylindrical substrate, and a rotatable heating drum is provided in which a voltage is applied between the transparent conductive layer and the conductive layer. , a photothermal conversion type recording device characterized in that the heating drum is used as a recording element.