JPH03116128A - Image forming device - Google Patents

Abstract

PURPOSE:To always obtain a stable picture even when a discharge tube is used as an exposure lamp by allowing the rate of plural filters occupied in the optical path of light reflected from an original or light transmitted through the original based on a tone correction value corresponding to the temperature of the exposure lamp to be changed and keeping the tone of the reflected light or transmitted light constant. CONSTITUTION:A temperature measuring means B measures the temperature of the discharging tube A; a control means C reads the tone correction value corresponding to the temperature, from a storage means D. The control means C controls a driving means E based on the read tone correction value; the driving means E drives plural filters F. The plural filters F allow the rate of occupancy to the optical path of the reflection light generated by reflecting the light emitted from the discharging tube to the original or the transmitted light generated by transmitting the original to be changed. Thus, even when the discharge tube is used as the exposure lamp, a stable picture is always obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to an image forming apparatus, and more particularly to a full-color image forming apparatus that exposes photosensitive paper using light from an exposure lamp.

In conventional image forming devices such as full-color copiers,
A halogen lamp was used as the exposure lamp.

Problem B1 to be Solved by the Invention In general, in a copying machine, when the sensitivity of photosensitive paper is the same, the greater the amount of light, the shorter the exposure time, and as a result, the copying speed can be increased.

However, it was not possible to increase the copying speed beyond a certain value with the light intensity of the halogen lamp.

Therefore, it has been considered to use a discharge tube such as a metal halide lamp as the exposure lamp. For example, in the case of a metal halide lamp, it is possible to obtain approximately three times the amount of light as a halogen lamp with the same electric power, and as a result, it is possible to increase the copying speed. However, a drawback of discharge tubes is that the color tone of the emitted light changes as the temperature changes. If the color tone of the light changes, it is impossible to obtain a stable image.

The present invention has been made to solve the above-mentioned problem α, and aims to provide an image forming apparatus that can always obtain stable images even when a discharge tube is used as an exposure lamp. .

[Means for Solving the Problems] In order to solve the above-mentioned problems, the image forming apparatus of the present invention includes a discharge tube used as an exposure lamp and a light emitted from the discharge tube that is reflected on the original. a plurality of filters for correcting the color tone of reflected light or transmitted light generated by passing through an original, a driving means for selectively moving the plurality of filters into and out of an optical path of the reflected light or transmitted light, and the discharge tube. temperature measuring means for measuring the temperature of the temperature measuring means; storage means for storing a color tone correction value corresponding to the temperature measured by the temperature measuring means; and control means for changing the ratio occupied by the plurality of filters.

[Operation] The temperature of the discharge tube is measured by the temperature measuring means, and the control means reads out the color tone correction value corresponding to the temperature from the storage means. The control means controls the driving means based on the read color tone correction value, and the driving means drives a plurality of filters, and the plurality of filters reflect the light emitted from the discharge tube onto the original. The ratio of the generated reflected light or transmitted light transmitted through the original document to the optical path is changed.

[Embodiment 1] Hereinafter, a full-color copying machine 40 embodying the present invention will be described.

FIG. 2 is a sectional view of the full color copying machine of the present invention.

Note that the photosensitive paper (consisting of microcapsule paper and color developer paper) that enables such copying is disclosed in Japanese Patent Application Laid-Open No. 58-88739.
This method has been proposed in a number of publications, etc., and will not be discussed in detail here.

The full-color copying machine 40 includes a document table glass 2 and a document table cover 1, the top plate of which is movable in the left and right directions, as shown in the figure.
A desired document can be placed face down on the document table plus 2. Full color copy machine 4
A light source consisting of a cylindrical metal halide lamp 3 and a semi-cylindrical reflection gt 4 arranged so as to surround it is fixed to the upper right side of the 0, and the document table irradiates a line of light toward the lath 2. do.

Therefore, the light emitted from the metal halide lamp 3 can sequentially illuminate the entire surface of the document table glass 2 from the left end to the right end by moving the document table glass 2 in the left-right direction. The light emitted from the light source passes through the transparent document table glass 2 and is reflected by the document placed on it, but the document table is placed on the glass plate 2 to prevent this reflected light from leaking from areas other than the document. A document table cover 1 that covers the top surface is provided.

In addition, in order to use the light emitted from the metal halide lamp 3 to irradiate the original with high efficiency, a beam 7 and a reflector 5 are placed on the left side of the light source to reflect the light that does not go directly to the original and use it again to irradiate the original. There is.

Note that the metal halide lamp 3 has a characteristic that the color tone of the light it generates changes depending on its temperature.

On the right side of the metal halide lamp 3, a seven-hole 6 and a louver 7 for introducing air from the outside are provided. As a result, air can be efficiently applied to the document table glass 2. Light emitted from the metal halide lamp 3 and reflected from the document placed on the document table glass 2 passes through the filter 8 and enters the lens 9.

The filter 8 is used to change the light transmission characteristics according to the sensitivity characteristics of the microcapsule paper 37 and adjust the color tone of the copied image, and includes three types of filters 8 a for the three primary colors of light.
It consists of t 8 b and 8 c. Filters 8a, 8
b, 8c and 8c are selectively driven by the filter driving device 55, and the ratio of their occupancy to the optical path of the reflected light is changed. The filter drive device 55 is, for example, disclosed in Japanese Utility Model Application No. 63-4516.
As disclosed in No. 7, a device that selectively drives three filters using two motors and two gears may be used, or other devices may be used. The lens 9 is attached to a lens mounting plate 10, and allows minute angle adjustment with respect to the optical path.

The light focused by the lens 9 is changed direction by 180 degrees by two reflection mirrors 11, and is imaged on the microcapsule paper 37 closely positioned below the exposure stage 19. The two reflecting mirrors 11 are fixed to a mirror mounting plate 12, and the optical path length and focus are adjusted by finely adjusting the mounting position of the mirror mounting plate 12.

On the other hand, a strip-shaped microcapsule paper 37 is wound around a cartridge shaft 14 and housed in a removable cartridge 13 disposed below the platen glass 2. and pressure developing device 20ft:3
1, the winding pongee reaches 25.

That is, the microcapsule paper 37 coming out from the lower part of the cartridge 7 13 is guided by the feed roller 15 and the tie roller 17 and passes below the exposure table 19, and then is transferred to the pressure developing device 2.
0. Thereafter, the microcapsule paper 37 that has passed through the pressure developing device 20 is guided to a peeling row 223 and a meandering adjustment roller 24, and then wound onto a winding pongee 25.

The unexposed microcapsule paper 37 after leaving the cartridge 13 is maintained in an unexposed state by the light shielding cover 16.

The transport speed of the microcapsule paper 37 is capsule paper feed a.
- The latent images of predetermined lines of the document are sequentially formed on the microcapsule paper 37 as it passes through the exposure table 19 because it is controlled at a constant speed by It is formed.

Further, a developer paper cassette 32 containing cut paper type developer paper 38 is provided below the pressure developing device 20, and the developer paper 38 is taken out one by one by a half-moon roller 33, and the developer paper cassette 32 is taken out one by one by a half moon roller 33, After the leading end is aligned by the registration gate 35, the paper is transported to the paper entrance of the pressure developing device 20.

Therefore, the microcapsule paper 37 and the color developer paper 38 are supplied to the pressure developing device 1120 in a state in which they are in close contact with each other and are integrated. The pressure developing device 20 is composed of a small diameter roller 21 and a backup roller 31. The microcapsule surface on which the latent image of the microcapsule paper 37 is formed and the color developer paper 3
The roller 8 is sandwiched between the small diameter roller 21 and the backup roller 31 while being in contact with the color developer coated surface of the roller 8 on the inside, and pressure is applied thereto. This pressure breaks the unexposed microcapsules! An image is formed on the color developing paper 38.

The microcapsule paper 37 and the color developer paper 38 that have come out of the pressure developing device are carried out by the capsule paper feed a-222, and the microcapsule paper is moved upward by the peeling roller 23, and the color developer paper 3
8 are orthogonally separated.

After the color development of the color developing paper 38 is promoted by the heat fixing device and an image is formed, the color developing paper 38 is conveyed to the first tray 27 with the image side facing up. The heat fixing device is composed of a hollow heat roller 29 having a heater 30 inside and a color developing paper feed row 228.

The separated microcapsule paper passes through a meandering adjustment row 224 and is wound onto a take-up pongee 25.

Next, the configuration of the main parts of the present invention will be explained using the block diagram of FIG. A cPU 51 as a control means, a ROM 52 as a storage means, and a lamp driver 53.
A/D converter 54. A filter drive device 55 is connected to each. The ROM 52 stores a program for the entire apparatus as well as six color tone correction values. The color tone correction value is a combination of two values indicating which color filter should be moved and how much, and this value corresponds to the temperature of the metal halide lamp 3. A metal halide lamp 3, which is a discharge tube, is connected to the lamp driver 53, and a thermocouple 57 is in contact with the base of the metal halide lamp 3.

A thermocouple 57 is connected to the A/D converter 54.

Next, the operation of each component during copying will be explained.

Now, after opening the document platen cover 1 and placing the original on the document platen glass 2, if you press the start button (not shown), the document platen glass 2 will first move to the right in FIG. The base glass 2 stops at a position where the left end faces the light source. Thereafter, with the metal halide lamp 3 turned on, the document table plus 2 is moved to the left. The light emitted from the metal halide lamp 3 is reflected by the original, and then passes through the filter 8. After being reflected by the lens 9 and the two reflecting mirrors 11, an image is formed on the microcapsule paper 37 located below the exposure table 19. At this time, the microcapsule paper 37 is moved to the left on the exposure table 19 at the same speed as the moving speed of the document table lath 2, so the image on the document is formed as a latent image on the microcapsule paper 37. be done.

As the document platen glass 2 moves to the left, the half-moon roller 3
3, the gray colored paper 38 is taken out from the developing paper sheet 32 and supplied to the pressure developing device 20 in a superimposed state with the exposed microcapsule paper 37, where the latent image on the microcapsule paper 37 is developed. The image is transferred onto developer paper 38.

Thereafter, the developing paper 38 is thermally fixed by a thermal fixing device and then discharged outside the full-color copy W140. On the other hand, the microcapsule paper 37 that has passed through the pressure developing device 20 is
8 are sequentially wound on the winding shaft 25. When the document table plus 2 finishes moving to a position where its right end faces the light source, copying of the document is completed and the metal halide lamp 3 is turned off.

Now, a method of controlling the metal halide lamp 3 and filter 8 during the formation of the above-mentioned latent image will be explained using chart 70 in FIG. 4.

In step S1 (hereinafter simply referred to as S1).

The same applies to other steps. ) The lamp driver 53 turns on the metal halide lamp 3 in response to a signal from cpusl. In S2, the thermocouple 57 measures the temperature of the base of the metal halide lamp 3, and the A/D converter 54 converts it into an electrical signal and sends it to the CPU 51. S
In step 3, the CPU 51 reads out the color tone correction value corresponding to the temperature input as an electric signal from the ROM 52, and
The smell determines which color filters 8a, 8b, and 8c should be moved and how much. In S5, the filter driving device 55 moves the determined filter 8 by the determined amount in response to a signal from the CPU 51.
- S6 are repeated, and even if the temperature changes during the process, the driving amount of the filter 8 changes, and the reflected light is maintained at a constant color tone.

When it is confirmed that the exposure is completed in S6, the lamp driver 53 is activated in response to a signal from the CPU 51 in S7.
The metal halide lamp 3 is turned on.

As detailed above, in the full-color copying machine 40 of the present invention, the ratio of the three filters 8ay, sbl, and 8c to the light reflected from the document is changed by the color tone correction value corresponding to the temperature of the metal halide lamp 3. Since the color tone of the reflected light is kept constant, a stable image can always be obtained regardless of the temperature of the metal halide lamp 3.

In this embodiment, the temperature of the metal halide lamp 3 is measured with a thermocouple 57 that is in contact with the base.
Other methods are also possible.

Further, in this embodiment, a metal halide lamp was used as the exposure lamp, but other lamps such as a xenon lamp or a high-pressure sodium lamp may also be used.

Furthermore, it can also be used in an image forming apparatus that allows light from an exposure lamp to pass through the original.

Other changes are possible without departing from the spirit of the invention.

[Effects of the Invention] As is clear from the detailed description above, in the image forming apparatus of the present invention, a plurality of filters occupying the optical path of reflected light or transmitted light from the document are controlled by the color tone correction value corresponding to the temperature of the exposure lamp. Since the color tone of the reflected light or transmitted light is kept constant by changing the ratio of I can do it.

[Brief explanation of drawings]

@Figures 1 to 4 show embodiments embodying the present invention. Figure 1 is a block diagram conceptually illustrating the present invention, and Figure 2 is a full-color copy embodying the present invention. FIG. 3 is a block diagram showing the configuration of the main parts of the present invention in this embodiment, and FIG. 4 is a 70-chart diagram showing the control method of the metal halide lamp and filter in this embodiment. It is. 3...Metal halide lamp, 8...Filter, 5
1... CPU, 52... ROM, 53... lamp driver, 5... filter drive device.

Claims (1)

[Claims] 1. A discharge tube used as an exposure lamp, and correcting the color tone of reflected light generated when the light emitted from the discharge tube is reflected on an original, or transmitted light generated when transmitted through the original. a plurality of filters, a driving means for selectively moving the plurality of filters into and out of the optical path of the reflected light or transmitted light, a temperature measuring means for measuring the temperature of the discharge tube, and a temperature measured by the temperature measuring means. A storage means for storing a color tone correction value corresponding to temperature; and a control means for controlling the driving means based on the color tone correction value and changing the proportion of the plurality of filters in the optical path. Features of the image forming device.