JPH01202740A - Thermal copying device - Google Patents

Abstract

PURPOSE:To make compensation for the influence on transfer density and to always obtain a uniform density image by arranging a reflecting material brought into contacted with a plane opposing to the transparent part material of exposure light sources or close to the plane and permitting the specific projection area on the transparent part material and reflecting again only such reflected light to the transparent part material. CONSTITUTION:The reflecting material 7a and 7b which permit the projection area of 50% or less of the effective copying region on the transparent part material are arranged so as to be brought into contact with or close to at least the light source planes opposing to the transparent part material. Most of the light of the exposure light sources is condensed in the direction of the transparent part material at the reflecting material 7a and 7b, and the light to be projected again to a copying original 5 among the light reflected by the non-image part of the copying original 5 is almost completely reduced. Therefore, most of the reflecting light caused by the non-image part of the copying original 5 is removed without reducing the exposure light source efficiency, and regardless of the occupation rate and position of the non-image part, the transcription density change is compensated. Thus, the uniform density image is always obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal copying apparatus that brings a copy original into close contact with a material to be copied and performs thermal copying by irradiating light from an exposure light source.

2. Description of the Related Art In recent years, image forming apparatuses that utilize light beams as thermal copying apparatuses have been frequently used in electronic flash discharge tube plate making machines, OHP document producing machines, and the like.

A thermal copying device that performs thermal copying by forming a temperature difference pattern by light irradiation from an exposure light source has a method of forming a temperature difference pattern by creating a temperature difference pattern based on the difference in light absorption between the image area and the non-image area of the copy document. There are a method of forming a differential pattern, a method of using a mask sheet having a means for selectively transmitting light, and the like.

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

FIG. 5 shows an example of a transfer section of a conventional thermal copying apparatus. In FIG. 5, lla and 1)b are exposure light sources, and 12 is a reflective material. 13 is a transparent member, and the opposing member 1
4, a copy original 15 and a non-copy material 16 are sandwiched and brought into close contact with each other.

The operation of the thermal copying apparatus configured as described above will be explained.

The copy original 15 and the non-copy material 16 are brought into close contact between the transparent member 13 and the opposing member 14, and the exposure light sources 1) a, ll
When exposure light sources 1) a and llb emit light, the light emitted from the exposure light sources 1) a and 1) is reflected directly or by the reflective material 12, passes through the transparent member 13, and is irradiated onto the copy original 15. At this time, in the area recorded as an image area, after 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. 60-281351).

Problems to be Solved by the Invention However, in the above configuration, the exposure light source 1) a;
The light irradiated from the copy original 15 is reflected by a high reflectance portion in the transfer area of the copy original 15, that is, a non-image area, and this reflected light is reflected again by the reflective material 12 and is irradiated onto the copy original 15 again. For this reason, the exposure light filla,
Even if the energy of the light irradiated from Ilb is the same, the density of the ink transferred to the non-copying material 16 (hereinafter referred to as transfer density) depends on the proportion and position of the non-image area in the transfer area of the copy original 15. However, there was a problem in that the amount of energy (described in detail) changes.

Another method is to place a light absorbing material on the bottom surface of the reflective material 12 facing a plurality of light sources to absorb the light reflected by the non-image area of the copy original 15 and compensate for the transfer density. However, since the light emitted from the lower surface of the exposure light source is absorbed by the absorbing material, there is a problem in that the efficiency of the exposure light source becomes extremely poor.

In view of the above-mentioned problems, the present invention always outputs an image of uniform density by compensating for the change in transfer density even if the ratio and position of the non-image area of the copy original 15 changes, and by the compensation, the exposure light source 1) a.

1) To provide a thermal copying apparatus that does not reduce the efficiency of b.

Means for Solving the Problems In order to solve the above problems, the thermal copying apparatus of the present invention is arranged in contact with or close to at least the surface of the exposure light source in the direction opposite to the direction of the transparent member, and the projection light onto the transparent member is A reflective material whose area is 50% or less of the effective copying area on the transparent member is provided, and other than this reflective material, there is no reflective material that reflects the light reflected by the non-image area of the copy original back toward the transparent member. It has the following configuration.

According to the above-described structure, most of the light from the exposure light source is focused toward the transparent member by the reflective material, and most of the light reflected by the non-image area of the copy document is irradiated again to the copy developer. This feature removes most of the light reflected by the non-image areas of the copy original without reducing the efficiency of the exposure light source, and it is possible to always obtain images with uniform density regardless of the proportion and position of the non-image areas of the copy original. DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal copying apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a transfer section of a thermal copying apparatus according to a first embodiment of the present invention. In FIG. 1, a copy manuscript 5 and a recording paper 6
is supported by a drum 4 and has a predetermined curvature.
are pressed against the drum 4 with a predetermined force and are brought into close contact with each other. Two xenon flash lamps la and lb, which are exposure light sources, face the lower side of the glass plate 3, and the glass plate 3 of the xenon flash lamps la and lb
Is there aluminum on the opposite side? a and 7b are deposited.

As shown in FIG. 2, the copy original 5 has an aluminum vapor deposition layer 5b provided on one side of a transparent sheet 5a, and a heat-melting ink 5C coated on the other side. The aluminum evaporation layer 5b is then removed by discharge breakdown recording in accordance with the pattern to be copied (hereinafter, a copy original having this configuration will be referred to as a mask sheet).

The recording paper 6 and the copy original 5 are overlapped with one surface coated with the heat-melting ink 5C.

The operation of the thermal copying apparatus constructed as described above will be explained below with reference to FIGS. 1 and 2.

When the xenon flash lamps LA and LB emit light,
The light emitted from the top surface of the xenon flash lamps la, lb is directly emitted from the top surface, but the light emitted from the bottom surface is reflected by the aluminum 7a, 7b deposited on the bottom surface of the xenon flash lamps la, lb. The light is irradiated from the upper surface of the xenon Franche lamps la and lb. Therefore, the xenon flash lamp la
.

All the light from 1b is irradiated onto the upper surface so as not to reduce the efficiency of the xenon Franche lamps la and lb.

Light irradiated from the xenon flash lamps la and lb passes through the glass plate 3 and is irradiated onto the mask sheet 5. At this time, the portion where the aluminum vapor deposition 15b has been removed as an image area is irradiated with the heat-fusible ink 5c through the transparent sheet 5b, and after photothermal conversion, the heat-fusible ink 5G is melted and transferred to the recording paper 6. be done. Therefore, almost no light is reflected back from the image area and there is no problem, but in the area where the aluminum vapor deposition layer 15b remains as a non-image area, most of the irradiated light is reflected by the aluminum vapor deposition layer 5b. . This reflected light passes through the glass plate 3 again and returns.However, the reflecting mirror that reflects the light again is aluminum 7a deposited on the bottom surface of the xenon flash lamps la and lb.

There is none other than 7b, but this aluminum 7a, 7
The light incident on b is from xenon flash lamps la, l.
It has passed through the glass wall of b and the gas inside, and the aluminum 7a.

The light reflected by 7b must also pass through the glass walls and internal gas of the xenon flash lamps la and Ib. In particular, since the attenuation of light due to transmission through gas is large, the light irradiated onto the mask sheet 5 again does not affect the transfer density. Therefore, the change in transfer density due to the ratio 1 position occupied by the non-image area of the copy original 5 is compensated.

As described above, according to this embodiment, aluminum 7 is used as a reflective material on the lower surface side of the xenon flash lamps la and lb.
a, 7b, xenon flash lamp la, lb
By adopting a configuration in which there is no reflective material other than aluminum 7a and 7b near the xenon Franche lamp la.

It is possible to always obtain an image of uniform density regardless of the position of the non-image portion of the copy document 5 without reducing the efficiency of the image forming apparatus 1b.

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

FIG. 3 shows a transfer section of a thermal copying apparatus showing a second embodiment of the present invention. In FIG. 3, la.

1b is a xenon flash lamp, 3 is a glass plate, 4 is a drum, 5 is a copy original (mask sheet), 6 is a recording paper, ? a and 7b are aluminum.

The above configuration is similar to the configuration shown in FIG. The difference from the configuration shown in Fig. 1 is that the reflector 2 is provided on the side of the xenon flash lamps la and lb so that the light from the xenon flash lamps la and lb is irradiated to the end portion of the transfer area. It is.

The operation of the thermal copying apparatus configured as described above will be explained below using FIGS. 2 and 3. When the xenon flash lamps la and lb emit light, the light reflected by the reflecting mirror 2 mainly irradiates the edge portions of the transfer area, thereby compensating for the density difference between the edge portions and the center portion of the transfer area. Further, since the reflecting mirror 2 is oriented in a direction to remove the light reflected by the non-image area 5b of the copy original 5, the reflected light from the non-image area 5b is removed in the same manner as in the first embodiment. The copy document is hardly irradiated again and the transfer density is not affected. As described above, by providing the reflecting mirror 2 at a position where the light from the xenon flash lamps la and lb illuminates the end portion of the transfer area, the transfer area is not affected by the reflected light from the non-image area 5b. It is possible to compensate for the difference in density between the edges and the center of the image.

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

FIG. 4 shows a transfer section of a thermal copying apparatus showing a third embodiment of the present invention. In FIG. 4, La.

1b is a xenon flash lamp, 3 is a glass plate, 4 is a drum, 5 is a copy original (mask sheet), 6 is a recording paper, and 7a and 7b are aluminum.

The above configuration is similar to the configuration shown in FIG. The difference from the configuration shown in Figure 1 is that the reflector 2 is replaced by a xenon flash lamp.
The two points are that the xenon flash lamps are arranged around the xenon flash lamps la and lb, and that a light absorbing material 8 is provided on the reflecting mirror 2 below the xenon flash lamps la and lb.

The operation of the thermal copying apparatus constructed as described above will be described below with reference to FIGS. 2 and 4.

The xenon flash lamps la and lb emit light, and most of the light that is reflected by the aluminum vapor deposited layer 5b in the non-image area of the copy document 5 and returns to the light absorption material 8 below the xenon flash lamps la and lb. Absorbed. Therefore, changes in transfer density due to this reflected light are compensated for.

Further, the reflecting mirror 2 is a xenon flash lamp la.

The light from the xenon Franche lamps la and lb is reflected and irradiated onto the edge of the transfer area to compensate for the transfer density at the edge of the transfer area.
It is arranged so as not to leak to the outside of the reflecting mirror 2 except for the direction. In addition, the reflector 2 also serves as a frame that supports the glass plate 3 and the light absorbing material 8, and can also be used as a ventilation path for cooling the glass plate 3. temperature increases).

As mentioned above, the xenon flash lamp LA.

A reflecting mirror 2 is arranged around the xenon fluorescent lamp 1b, and a light absorbing material 8 is provided on the reflecting mirror 2 below the xenon flash lamps la and lb to ensure that the reflected light from the copy original 5 is absorbed and the copy original The proportion occupied by the non-image area of 5.

An image with uniform density can always be obtained regardless of the position and regardless of whether it is at the edge or the center of the transfer area.

Further, the reflecting mirror 2 can be used as a frame and as a ventilation passage for cooling the glass plate 3 while preventing light from leaking to the outside of the reflecting mirror 2.

In the embodiment, a glass plate is used as a member for bringing the copy original into close contact with the material to be copied, but a transparent resin member may also be used. Furthermore, although recording paper is used as the copying material, other copying materials may be used. Furthermore, although the drum that holds the recording paper is cylindrical, it may also be flat. In addition, the original to be copied was made into a sheet that transmits light according to the pattern, but a general original was used as the original to be copied, and a thermochromic transparent sheet was used as the material to be copied. A transparent sheet may be used to develop color, or a transparent original and a thermosensitive coloring sheet may be used.Also, although a xenon flash lamp was used as the light source for exposure, other light sources may be used.
Furthermore, although the number of light sources is two, it may be one, three or more.

Although aluminum is used as the reflective material, other reflective materials may also be used. Also, aluminum was vapor-deposited on the xenon flash lamp, but an aluminum reflective material may be attached to the xenon flash lamp or placed close to the xenon flash lamp. Also, although the light absorbing material is provided on the reflecting mirror, it may be provided near the reflecting material.

Effects of the Invention As described above, the present invention provides a reflective material in contact with or in close proximity to at least the surface of the exposure light source in the direction opposite to the direction of the transparent member, so that the reflected light from the non-image area of the copy document is reflected back to the transparent member. By adopting a configuration in which a reflective material that reflects in the direction is not provided or a light absorbing material is provided, the influence of reflected light from the non-image area of the copy original on the transfer density can be compensated for without reducing the efficiency of the exposure light source. However, images with uniform density can always be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a transfer section of a thermal copying apparatus according to a first embodiment of the present invention, FIG. 2 is a sectional view of a copy document, and FIG. 3 is a thermal copying apparatus according to a second embodiment of the present invention. FIG. 4 is a front view showing the transfer section of a thermal copying device according to a third embodiment of the present invention, and FIG. 5 is a front view showing the transfer section of a conventional thermal copying device. It is a diagram. la, lb...Xenon flash lamp, 2
...Reflector, 3...Glass plate, 4...
...Drum, 5...Copy manuscript, 6...
... Recording paper, 7a, 7b... Aluminum,
8...Light absorbing material. Name of agent: Patent attorney Toshio Nakao (1 person) Figure 1: Ten Thousand Aluminum Figure 2

Claims (3)

[Claims] (1) In order to perform copying by irradiating light onto a copy original and a material to be copied that are in close contact between a transparent member, a facing member facing the transparent member, and the transparent member and the facing member, A light source placed in a direction opposite to the direction of the opposing member when viewed from the transparent member, and a light source placed in contact with or close to at least a surface of the light source in a direction opposite to the direction of the transparent member, and projected onto the transparent member. and a reflective material whose area is 50% or less of the effective copying area on the transparent member. (2) In order to collect light from the light source toward the transparent member, a reflecting member is provided close to the light source and positioned to sandwich the light source. Thermal copying device. (3) In order to collect the light from the light source in the direction of the transparent member, a reflective material placed near the light source and a reflective material facing the light source placed in the opposite direction to the transparent member as seen from the light source. The thermal copying apparatus according to claim 1, further comprising an absorbent material.