JPH0786640B2 - Thermal copying machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive copying apparatus in which a copy original and a material to be copied are brought into close contact with each other and heat-sensitive copying is performed by irradiation of light from an exposure light source.

2. Description of the Related Art In recent years, an image forming apparatus using light rays as a thermal copying apparatus has been widely used in an electronic flash discharge tube type plate making machine, an OHP original making machine, and the like.

A thermal copying machine that forms a temperature difference pattern by irradiating light from an exposure light source and performs thermal copying is a method of forming a temperature difference pattern, in which a temperature difference is caused by a difference in light absorption between an image portion and a non-image portion of a copy original. There are a method of forming a difference pattern, a method of using a mask sheet having a means capable of selectively transmitting light, and the like.

An example of the above-described conventional thermal copying apparatus will be described below with reference to the drawings.

FIG. 4 shows an example of a transfer portion of a conventional thermal copying apparatus. In FIG. 4, 11a and 11b are exposure light sources, and 12 is a reflecting material. Reference numeral 13 denotes a transparent member, which faces the facing member 14 and holds the copy original 15 and the non-copying material 16 so that they are in close contact with each other.

The operation of the heat-sensitive copying apparatus configured as described above will be described.

The copy original 15 and the copy material 16 are in close contact with each other between the transparent member 13 and the facing member 14, and when the exposure light sources 11a and 11b are made to emit light, the light emitted from the exposure light sources 11a and 11b is directly or reflected. Copy original reflected by material 12 and transmitted through transparent member 13
Irradiated to 15. At this time, in the portion recorded as the image portion, after the photothermal conversion, the ink applied to the copy original 15 is melted and transferred to the copy material 16 (for example, Japanese Patent Application No. 60-
No. 281351).

However, in the configuration as described above, the exposure light source 11a, 11b
The further irradiated light is reflected by a portion having a high reflectance in the transfer area of the copy original 15, that is, a non-image portion, and the reflected light is reflected again by the reflecting material 12 and is again irradiated on the copy original 15. Therefore, even if the energies of the light emitted from the exposure light sources 11a and 11b are the same, the ink transferred to the material 16 to be copied depends on the proportion and position of the non-image portion in the transfer area of the copy original 15. There is a problem that the density (hereinafter referred to as transfer density) changes. Further, there is a problem that the transfer density of a portion near the end of the area in the transfer area becomes lower than the transfer density in the center of the area due to the positional relationship between the exposure light sources 11a and 11b and the reflected light of the non-image area of the copy document 15. Was.

In view of the above problems, the present invention compensates for the change in the transfer density even when the ratio and position of the non-image portion of the copy document 15 change, and the density difference between the end of the transfer area and the center of the transfer area. The present invention provides a thermal copying apparatus which always outputs an image of uniform density by compensating for the above.

Means for Solving the Problems In order to solve the above problems, a thermal copying apparatus of the present invention is placed between a plurality of exposure light sources so as to face a transparent member, and the surface of the transparent portion direction is a light absorbing material and the opposite direction. The surface has a reflection absorbing material which is a reflecting material.

Operation According to the present invention having the above-described structure, the light reflected by the non-image portion of the copy original at the time of copying is absorbed by the light absorbing material on the surface of the reflection absorbing material in the direction of the transparent member, and the reflected light is irradiated to the copy original again. Since it does not affect the transfer density, the light emitted from the exposure light source in the direction opposite to the direction of the transparent member does not affect the transfer density. Since the light is reflected by the reflection material on the surface in the opposite direction and mainly irradiates the end portion of the transfer area, the transfer density at the end portion of the transfer area is prevented from lowering. Therefore, regardless of the proportion, position, and edge or center of the transfer area of the non-image part of the copy document,
An image with uniform density can always be obtained.

Embodiment A thermal copying machine according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a transfer portion of a thermal copying machine according to a first embodiment of the present invention. In FIG. 1, the recording paper 6 of the copy original 5 is supported by the drum 4, and is pressed against the drum 4 by a predetermined force by the glass plate 3 having a predetermined curvature to be in close contact with each other. Below the glass plate 3 is an exposure light source 2
The xenon flash lamps 1a and 1b of the book are facing each other,
In the meantime, a reflection / absorption material having a light absorbing material on the surface facing the transparent member and a reflecting material on the opposite surface is attached, and a reflecting mirror 2 is arranged around the xenon flash lamps 1a, 1b.

As shown in FIG. 2, the copy original 5 is provided with an aluminum vapor deposition layer 5b on one surface of a transparent sheet 5a and a heat-melting ink 5c on the other surface.
Is applied. Then, the aluminum vapor deposition layer 5b is removed by discharge breakdown recording according to the pattern to be copied (hereinafter, the copy original having this structure is referred to as a mask sheet). The recording paper 6 and the copy original 5 are overlapped on the surface coated with the hot-melt ink 5c.

The operation of the heat-sensitive copying apparatus configured as described above will be described below with reference to FIGS. 1 and 2.

When the xenon flash lamps 1a and 1b emit light, the light emitted from the xenon flash lamps 1a and 1b is directly or reflected by the reflecting mirror 2 and transmitted through the glass plate 3 to be applied to the mask sheet 5. At this time, the portion where the aluminum vapor deposition layer 5b is removed as the image portion is transmitted through the transparent sheet 5b and is irradiated with the heat-meltable ink 5c, and the heat-meltable ink 5c is melted after the photothermal conversion and is recorded on the recording paper 6. Transcribed. Therefore, there is almost no light reflected back from the image part and there is no problem, but in the part where the aluminum vapor deposition layer 5b remains as the non-image part, most of the irradiated light is the aluminum vapor deposition layer.
Reflected by 5b. This reflected light passes through the glass plate 3 again and returns. Regarding the light that tries to pass between the xenon flash lamps 1a and 1b among the reflected light,
It is absorbed by the light absorbing material 7a on the upper surface of the reflection absorbing material 7.
Further, the light passing between the xenon flash lamp 1a or 1b and the reflecting mirror is repeatedly attenuated by the reflecting mirror 2 and the reflecting material 7b on the lower surface of the reflecting / absorbing material 7 several times. Therefore, the change of the transfer density depending on the position and the position of the non-image portion of the copy document 5 is compensated.

Also, when the xenon flash lamps 1a, 1b emit light, the light emitted from the bottom of the xenon flash lamps 1a, 1b is
The light is reflected by the reflecting mirror 2 and the reflecting material 7b and is mainly irradiated to the end portion of the transfer area. Therefore, the difference in the transfer density between the end portion and the central portion of the transfer area is improved.

Considering the above-mentioned role, the reflection absorbing material 7 exerts a remarkable effect if the effective length in the distance direction between the xenon flash lamps 1a and 1b is about 70% or more of the distance between the xenon flash lamps 1a and 1b. You can

As described above, according to the present embodiment, by providing the reflection absorbing material 7 between the xenon flash lamps 1a and 1b, the surface in the transparent member direction is the light absorbing material 7a and the surface in the opposite direction is the reflecting material 7b, It is possible to always obtain an image having a uniform density regardless of the proportion and position of the non-image portion of the copy document 5 and the end portion or the central portion of the transfer area.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows a transfer portion of a thermal copying machine showing a second embodiment of the present invention. In FIG. 3, reference numeral 2 is a reflecting mirror, 3 is a glass plate, 4 is a drum, 5 is a copy original, and 6 is a recording sheet. The above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that there are three xenon flash lamps 1a, 1b, 1c and two sets of reflection absorbing materials 7, 8 are provided between the xenon flash lamps 1a, 1b, 1c.

The operation of the heat-sensitive copying apparatus configured as described above will be described below with reference to FIGS. 2 and 3.

Of the light emitted by the xenon flash lamps 1a, 1b, 1c, reflected by the aluminum vapor deposition layer 5b in the non-image part of the copy document 5, and returned, between the xenon flash lamps 1a, 1b and between the xenon flash lamps 1b, 1c. The light that is going to pass through is absorbed by the light absorbing materials 7a and 8a on the upper surfaces of the reflection absorbing materials 7 and 8, respectively. The light passing between the xenon flash lamp 1a or 1c and the reflecting mirror 2 is repeatedly reflected and attenuated by the reflecting mirror 2 and the reflecting materials 7b and 8b on the lower surfaces of the reflecting and absorbing materials 7 and 8 several times. Therefore, the change in the transfer density due to the reflected light is compensated.

Also, when the xenon flash lamps 1a, 1b, 1c emit light, the light emitted from the lower part of the xenon flash lamps 1a, 1b, 1c is reflected by the reflecting mirror 2 and the reflecting materials 7b, 8b, and the end portion of the transfer area. Is irradiated. Therefore, the difference in the transfer density between the edge and the center of the transfer area is improved.

Here, the reflection absorbing materials 7 and 8 are the same as in the case of the first embodiment,
If the effective length in the distance direction between the xenon flash lamps 1a, 1b or 1b, 1c is about 70% or more of the distance between the xenon flash lamps 1a, 1b or 1b, 1c, a remarkable effect can be obtained.

Further, by using three xenon flash lamps 1a, 1b, 1c, it becomes possible to irradiate light in a wider area than in the case of two xenon flash lamps, and thus the transfer area can be made large. In addition, when making a copy of a larger area than the transfer area, this is divided into several times, but as described above, the transfer area can be made wider than in the case of two xenon flash lamps. Can be reduced. Therefore, the temperature rise of the glass plate 3 can be suppressed low. (When copying, the temperature of the glass plate 3 rises due to the emission of the xenon flash lamps 1a, 1b, 1c. When the temperature of the glass plate 3 changes, the transfer density also changes, so it is surrounded by the reflector 2 and the glass plate 3. It is also possible to cool the glass plate 3 by blowing air to the exposed part with a fan. Therefore, in this case, it can be said that the glass plate 3 can be easily cooled.) Also, the xenon flash lamps 1a, 1b, 1c Since the inner portions 1a and 1c mainly irradiate the end portion of the transfer region with light, it is possible to improve the density difference between the end and the center of the transfer region.

As described above, by providing three xenon flash lamps 1a, 1b, 1c and two sets of reflection absorbing materials 7, 8 between them, the first
In the case of the embodiment described above, it is possible to obtain an image having a uniform density in a wider transfer area, and at the same time suppress the temperature rise of the glass plate 3.

In the first and second embodiments, the member for bringing the copy original and the material to be copied into close contact with each other is a glass plate, but a transparent resin member may be used. Although the material to be copied is a recording sheet, other materials to be copied may be used. Further, although the drum for holding the recording sheet has a cylindrical shape, it may have a flat surface. Although the copy original is a sheet that transmits light according to the pattern, a general original is used as the copy original and a heat-sensitive color-forming transparent sheet is used as the material to be copied to heat the colored portion of the general original to generate heat-sensitive transparent color. The sheet may be colored, or may be a transparent original and a thermosensitive coloring sheet. Although the exposure light source is a xenon flash lamp, other light sources may be used. Further, although the number of light sources is two or three, four or more light sources may be used. Along with this, one or more sets of reflection absorbing materials between the xenon flash lamps may be used. Although the position of the reflection absorbing material between the xenon flash lamps is on the line connecting the centers of the xenon flash lamps, it may be shifted from that position toward the transparent member or in the opposite direction, and the angle facing the transparent member may be changed. You may. Further, although the shape of the reflection / absorption material is a flat plate, other shapes may be used.

EFFECTS OF THE INVENTION As described above, the present invention is to provide a reflection / absorption material that is placed between exposure light sources so as to face a transparent member and has a surface in the transparent member direction as a light absorbing material and a surface in the opposite direction as a reflecting material. Thus, it is possible to always obtain an image with a uniform density by compensating for the influence on the transfer density due to the reflected light from the non-image portion of the copy document and the unevenness of the transfer density in the transfer area due to the position of the exposure light source and the like. .

[Brief description of drawings]

FIG. 1 is a front view showing a transfer portion of a heat-sensitive copying apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view of a copy original, and FIG. 3 is a heat-sensitive portion according to a second embodiment of the present invention. FIG. 4 is a front view showing the transfer section of the copying machine, and FIG. 4 is a front view showing the transfer section of the conventional thermal copying machine. 1a, 1b …… Xenon flash lamp, 2 …… Reflector,
3 ... glass plate, 4 ... drum, 5 ... copy manuscript, 6 ...
… Recording paper, 7,8 …… Reflective absorber, 7a, 8a …… Light absorber,
7b, 8b …… Reflective material.

Claims (1)

[Claims] 1. A transparent member, a facing member facing the transparent member, a copy original and a material to be copied, which are in close contact between the transparent member and the facing member, are irradiated with light to perform copying. ,
A plurality of light sources placed in a direction opposite to the direction of the facing member when viewed from the transparent member, and a reflector that is in the vicinity of the plurality of light sources and collects light from the plurality of light sources in the direction of the transparent member. A heat-sensitive material that is placed between the plurality of light sources so as to face the transparent member, and has a reflection-absorbing material whose surface facing the transparent member is a light-absorbing material and the opposite surface is a reflecting material. Copying device.