JPS63220233A - Heat sensitive copying device - Google Patents

Abstract

PURPOSE:To obtain an image of uniform density by unevenly projecting the light to a copy original to compensate the variance of temperature of a transparent member due to the cooling effect of the copy original or a material to be copied during the copying operation. CONSTITUTION:A transparent member 14, a counter member 13 facing the member 14, and plural light sources 15a and 15b which project the light to a copy original 11 and a material 12 to be copied, which are closely brought into contact with each other between the transparent member 14 and the counter member 13, to copy the original are provided, and each light source unevenly projects the light to the copy original 11 to compensate the variance of temperature of the transparent member 14. Consequently, the unevenness of copy density, which occurs because a part of the transparent member 14 is cooled by the copy original 11 or the material 12 to be copied which is fed during the copying operation, is compensated. Thus, the copy image of throughout uniform density is 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. It concerns compensation.

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

Exposure light source Q A thermal copying apparatus that forms a temperature difference pattern by light irradiation and performs thermal copying uses a method of forming a temperature difference pattern based on the difference in the amount of light absorption between the image area and the non-image area of the copy document. There are a method of forming a temperature difference pattern, a method of using a mask sheet having a means for selectively transmitting light, and the like. However, in a thermal copying device that uses light irradiation as described above, even if the image is transferred with a constant energy, the image density changes due to the temperature difference in the transfer section, so it is necessary to control the energy according to the temperature of the transfer section.

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

FIG. 5 shows a transfer section of a conventional thermal copying apparatus. In FIG. 5, 61 is an exposure light source, and 62 is a reflecting mirror. A glass plate 63 faces the drum 64 and holds the copy original 65 and the recording paper 66 in close contact with each other. 67 and 68 are guide rollers.

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

The copy original 65 and the recording paper 66 are fed from the left side of the figure between the glass plate 63 and the drum 64 and brought into close contact with each other.

Thereafter, the exposure light source 61 is made to emit light to melt the ink applied to the copy document 65 according to the light transmission pattern of the copy document 65, and transfer it onto the recording paper 66. Light is emitted every time the copy document 65 is fed a certain distance. (For example, Japanese Patent Application No. Sho 60-281351) Problems to be Solved by the Invention However, in the above configuration, the copy original 65 is fed while being in contact with the glass plate 63.
The surface temperature of is as shown in FIG. That is, the exposure light source 6
1, the temperature of the glass plate 63 rises compared to the ambient temperature, but on the A side where the copy original 65 is fed, the copy original 65 whose temperature is lower than the surface of the glass plate 630 and is approximately equal to the ambient temperature. Since the glass plate 63 is fed in, the surface temperature of the glass plate 63 becomes low on the A side as shown in FIG. If there is a temperature difference on the surface of the glass plate 63 as described above, there is a problem in that an uneven temperature bias is applied to the copy original 65, resulting in uneven copy density. In addition, since each copy is performed in an overlapping manner, the effective copying area is the area excluding both ends of the glass plate 63 as shown in the figure, and if the overlamp amount is large, only the area where the temperature is constant is effective. However, there are problems such as the effective copying area becomes narrow, the copying speed decreases, and the utilization efficiency of copying energy decreases, resulting in an increase in power consumption.

In view of the above-mentioned problems, the present invention compensates for non-uniformity of copy density due to the cooling effect of the transparent member caused by the original to be copied or the material to be copied during the copying operation using a simple method, and provides a thermosensitive sensor that always outputs images with uniform density. It provides a copying device.

Means for Solving the Problems In order to solve the above problems, the thermal copying apparatus of the present invention has the following features:
A transparent member, a facing member facing the transparent member, and a plurality of light sources that perform copying by irradiating light onto a copy original and a material to be copied that are brought into close contact between the transparent member and the facing member, each of which The light source is configured to non-uniformly illuminate the copy document in order to compensate for temperature irregularities in the transparent member.

Effect of the present invention With the above-described configuration, the present invention compensates for non-uniformity in copy density caused by cooling of a portion of the transparent member by the copy original or copy material sent during the copying operation.
A copy image with uniform density can be obtained over the entire surface.

EXAMPLE Hereinafter, a thermal copying apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a transfer section of a thermal copying apparatus in one embodiment of the present invention. In FIG. 1, a copy document II and a recording paper 12 are supported by a drum 13, and are pressed against the drum 13 with a predetermined force by a glass plate 14 having a predetermined curvature, so that they are brought into close contact with each other.

Two xenon flash lamps 15a and 15b, which are light sources for exposure, face each other in the vicinity of the glass plate 14, and a reflecting mirror 16 is arranged around the xenon flash lamps 15a and 15b.

As shown in FIG. 2, the copy original 1) is made of transparent sheet 1) a
An aluminum vapor deposited layer 1)b is provided on one side of the plate, and a heat-melting ink IIG is coated on the other side. Then, according to the pattern to be copied, the aluminum vapor deposited layer 1 is
)'b has been removed. Recording paper 12 and copy manuscript 1
) are coated with hot-melt ink llc and overlapped on one side.

In addition, the xenon Franche lamps 15a and 15b are connected to the discharge capacitors 33a and 31, as shown in FIG.
It is connected in parallel with 3b. 34 is a switch for making each circuit independent when the xenon flash lamps 15a and 15b emit light. The discharge capacitors 33a and 33b are charged by the power source 31, and the switch 34
After opening, the xenon flash lamps '15a and 15b emit light by a trigger pulse of the high voltage trigger electric m32.

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

The copy original 1) sent onto the drum 13 is
The glass plate 1 is overlapped with the recording paper 12 held on the glass plate 1.
4, it can be brought into close contact with a predetermined force. Then, when the xenon flash lamps 15a and 15b are turned on, the copy original 1
), where the aluminum evaporated layer 1) b is removed, the light passes through, and the area where the aluminum evaporated layer 1) b remains reflects the light, so the thermofusible ink llc receives light according to the pattern. It generates heat, melts, and transfers it to the recording paper 12.

Recording paper 12 held on drum 13, copy original 1)
Since it is continuously fed, it is fed together with the copy original 1) and rotates together with the drum 13.

The glass plate 14 is held in a predetermined position, and the copy document 1) advances while sliding on the surface of the glass plate 14. Then, each time the copy original 1) and recording paper 12 are fed a predetermined distance, light is emitted and copies are made.

When copying is performed as described above, the xenon flash lamps 15a, 15
The temperature of the glass plate 14 rises compared to the surrounding temperature due to the light emitted by the light source b. However, the side of the glass plate 14 into which the copy original 1) is fed (indicated by ``into'' in the figure) is cooled because the temperature of the copy original 1) is lower than that of the glass plate 14, and the side from which the copy original 1) exits. (indicated by B in the figure). The fed copy original 1) is heated by the glass plate 14 to the temperature of the glass plate 14, so that a temperature difference occurs in the copy portion. If the temperature of the copy document 1) differs, the amount of heat required to heat the thermofusible ink llc to its melting point varies, and therefore the energy required for copying also changes. Therefore, the xenon flash lamps 15a and 15b do not emit the same amount of light, and the discharge capacitors 33a and 33b have different capacities, so that the xenon flash lamp 15a on the side A, which has a lower temperature, emits light as shown in FIG. The xenon flash lamp 15b on the B side, which has a higher temperature, is configured to emit less light. Irradiation with a light intensity distribution as shown in FIG. 4 makes it possible to compensate for temperature irregularities on the glass plate 14 and to perform uniform copying.

As described above, according to this embodiment, the glass plate 14 is cooled by the copy original 1), thereby making it possible to compensate for non-uniform copying.

Further, as a second embodiment of the present invention, in FIG.
By arranging the xenon flash lamp 15a on the side into which the copy document 1) is fed (indicated by ``inward'' in the figure) shifted from the center line to the A side, the copy document 1) can be non-uniformly irradiated.

Further, as another embodiment of the present invention, it is also possible to make the shape of the reflecting mirror 16 asymmetrical so that the copy original 1) is irradiated non-uniformly.

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 member such as a transparent resin may also be used. Furthermore, although the drum that holds the recording paper has a cylindrical surface, it may also have a flat surface. In addition, we used a sheet that transmits light according to the pattern on the original to be copied, but we used a general original as the original to be copied and a thermochromic transparent sheet as the material to be copied. A transparent sheet may be colored, or a translucent original and a heat-sensitive coloring sheet may be used. Furthermore, 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 set to two, there is no problem in using three or more light sources.

Effects of the Invention As described above, the present invention compensates for the temperature unevenness of the transparent member that resides due to the cooling effect of the copy original and copying material during the copying operation by employing a configuration that non-uniformly irradiates the copy original. It is possible to obtain an image with uniform density.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the transfer section of a thermal copying apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a copied document, FIG. 3 is a circuit diagram of a xenon flash lamp, and FIG. FIG. 5 is a front view showing a transfer section of a conventional thermal copying device; FIG. 6 is a characteristic diagram showing the surface temperature of a transparent member of a conventional thermal copying device during a copying operation. . 1)...Copy manuscript, 12...Recording paper, 13...Drum, 14...Glass plate, 15a, 15b...Xenon Flash lamp, 16...Reflector. Name of agent Patent attorney Toshio Nakao 1 figure 1 fan 2 flash 15a 151 -1-binonfra, nslump early binonfurafumempu 4 figure 17〃I childish precepts

Claims (3)

[Claims] (1) A transparent member, a facing member facing the transparent member, and a light source that performs copying by irradiating light onto a copy original and a material to be copied that are in close contact between the transparent member and the facing member. A thermal copying apparatus, wherein the light source is configured to non-uniformly illuminate the copy original in order to compensate for non-uniform copy density caused by non-uniform temperature of the transparent member. (2) A thermal copying apparatus according to claim (1), characterized in that a plurality of light sources are arranged, and the light intensity of each light source is non-uniform so that the copied document is non-uniformly irradiated. (3) The light source is an electronic flash discharge tube, a plurality of the electronic flash discharge tubes are connected in parallel, and a discharge capacitor is connected with a different capacity for each electronic flash discharge tube, so that the light intensity of each light source can be adjusted. Claims (1) or (2), characterized in that the method is configured to non-uniformly irradiate the copied original.
The thermal copying apparatus according to any one of paragraphs.