JPS62273518A - Picture forming device - Google Patents

Abstract

PURPOSE:To eliminate ghosts produced when a color correction filter is inserted in a picture forming device which is provided with the color correction filter at the principal point section of lenses under a movable state and exposure glass in the exposure window of a photosensitive window, by making the exposure glass oblique to the optical path. CONSTITUTION:A colored original on platen glass 1 is exposure-scanned by a light source 2 which moves in the direction (a) at a uniform speed and the image light beams obtained by reflection are made incident on an exposure window 7 through a mirror 3 which is united with the light source 2, mirrors 4 and 5 which more in the same direction as the moving direction of the light source 2 at a speed which is half as fast as the moving speed of the light source 2 and are united with each other, and a lens system 6. Image forming lenses 61 and 62 are provided along an optical path (c) and the 1st and 2nd filter plates 64 and 65 and a diaphragm 66 are installed to the principal point section 63 of the lenses 61 and 62. The exposure glass 71 fitted in the exposure window 7 is made oblique to the optical path (c) and, when part of transmitted light is reflected by the glass 71, the reflecting light C' is made to get out of the optical path (c). Therefore, the reflecting light beams from the exposure glass 71 do not reach the filters inserted into the principal point section and occurrence of a ghost can be prevented.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to an image forming apparatus such as a color copying machine.

[Background of the invention]

Generally, this type of image forming apparatus exposes and scans a color original placed on a platen glass using a light source that moves at a constant speed.
The image light obtained by reflection is incident on an exposure window fitted with glass through a mirror that is integrated with the light source, a mirror that moves in the same direction as the light source, and a lens system. A color photosensitive material that moves in synchronization with the movement of a light source is sequentially exposed to light.

After exposure, the color photosensitive material is developed according to a certain development process to obtain a color copy image.

In the color image forming apparatus, it is necessary to correct the color of the image light according to the spectral sensitivity characteristics of each color of the color photosensitive material and to adjust the hue of the exposure light according to the color tone of the original. Three-color filters are provided at the principal point of the lens so that they can go in and out, and the amount (ratio) of each filter inserted is controlled. As such a three-color filter, a filter that absorbs a specific hue wavelength is used. Specifically, a yellow filter that absorbs blue light, a magenta filter that absorbs green light, and a cyan filter that absorbs red light are used.

However, when such filters are inserted into the principal point of the lens, a portion of the transmitted light may hit the exposure glass fitted in the exposure window and be reflected, and the reflected light may be re-reflected by the filter. This re-reflected light creates a secondary light source at the principal point of the lens and forms an image on the photosensitive surface of the photosensitive material, causing a ghost.

[Purpose of the invention]

In view of the above points, it is an object of the present invention to provide an image forming apparatus capable of eliminating ghosts caused by insertion of a filter.

[Structure of the invention]

In order to achieve the above object, the present invention provides a color correction filter that can be moved in and out of the lens principal point.

In an image forming apparatus in which an exposure glass is installed in an exposure window of a photosensitive material, the exposure glass is provided obliquely with respect to an optical path.

〔Example〕

The present invention will be described below based on embodiments shown in the accompanying drawings.

FIG. 1 is a diagram showing the exposure part in a color copying apparatus. A color original (not shown) placed on a platen glass 1 is exposed and scanned by a light source 2 moving at a constant speed in the direction of arrow a, and the light reflected there The obtained image light is transmitted to a mirror 3 which is integrated with the light source 2. 1/2 in the same direction as the moving direction of light source 2
integral mirror 4.5 and lens system 6 moving at a speed of
The light enters the exposure window 7 in which the exposure glass 71 is fitted. Outside the exposure window 7, the color photosensitive material R moves in the direction of arrow A in synchronization with the movement of the light source 2, and is sequentially exposed, and the exposed color photosensitive material undergoes color development, fixing, and bleaching.

The image is sent to a development processing section such as drying, so that a color copy image corresponding to a color original can be obtained.

FIG. 2 shows the lens system 6 and the exposure window 7. Imaging lenses 61 and 62 are arranged along the optical path C, and a first filter plate 64, a second filter plate 65 and It is equipped with an aperture 66.

The first filter plate 64 has yellow filters (Y filters) 64Y and magenta filters (M
A filter) 64M is arranged, and the center is a transparent part 64T.

The second filter plate 65 has a Y filter 64Y and a cyan filter (C filter) 65C arranged at both ends, and a transparent portion 64T in the center.

Both filter plates 64 and 65 have home positions at positions where the center of the M filter 64M and the center of the C filter 65C coincide with the optical axis C, and the arrows d in the opposite directions, respectively.
It is movable in the e direction (horizontal direction across the optical path C) in the range of insertion to 100% by a stepping motor 67°68.

The aperture 66 is connected to the exposure window 7 of the optical path C, as shown in FIG.
It consists of two diaphragm pieces 55a and 66b arranged so as to face from the top and bottom of the window 8 corresponding to the window 8 (vertical direction across the optical path C), and are controlled by a stepping motor 69 to approach and move away from each other. ing. The aperture piece 66a
and 66b allow the window 8 to be moved from the center of the opening range to either the open side or the closed side.

The exposure glass 71 fitted in the exposure window 7 is oblique with respect to the optical path C. This is when the first filter plate 4 and the second filter plate 65 are inserted into the principal point of the lens.
When the transmitted light hits the exposure glass 71 fitted in the exposure window and is partially reflected, the reflected light C' becomes (
This is to make it deviate from the optical path C. This results in
The reflected light from the exposure glass 71 does not reach the filter inserted into the principal point of the lens, thereby preventing the creation of a secondary light source here.

〔Effect of the invention〕

As described above, the present invention provides an image forming apparatus in which a color correction filter is removably provided at the principal point of a lens, and an exposure glass is provided in an exposure window of a photosensitive material, in which the exposure glass is provided obliquely with respect to the optical path. Because of this feature, even if some of the transmitted light that has passed through the one-color correction filter hits the exposure glass and is reflected, the reflected light will deviate from the optical path.

It does not reach the filter, does not create a secondary light source at the principal point of the lens, and has the excellent effect of effectively preventing ghosts.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the exposure scanning portion of a color copying apparatus according to an embodiment of the present invention, FIG. 2 is a schematic explanatory diagram of the lens system, FIG. 3 is an explanatory diagram of driving the filter plate, and FIG. The figure is an explanatory diagram of driving the aperture. 2-Light source 6- Lens system 61, 62-Imaging lens 63--Principal point portion 64--First filter plate 65--Second filter plate 7--Exposure window 71--Exposure glass Patent Applicant Roku Konishi Photo Industry Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] An image forming apparatus in which a color correction filter is removably provided at a principal point of a lens, and an exposure glass is provided in an exposure window of a photosensitive material, wherein the exposure glass is provided obliquely with respect to an optical path. Forming device.