JP2787791B2 - Copy camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffusion transfer type copying camera which is used for producing a printing plate.

[0002]

2. Description of the Related Art In a diffusion transfer type copying camera, a latent image is formed by exposing a planar image of an original to a photosensitive material called negative paper, and an image receiving material called positive paper is formed on the exposed photosensitive material. Are superimposed on each other, and this is put into a developer, and the image recorded on the photosensitive material is diffused and transferred to the image receiving material. In order to form a latent image on the photosensitive material, the type of imaging a document by copying camera, must be without distortion can accurately record up large document about A ₃ size, and have a scaling function To do so, the copying camera becomes very large and heavy. Therefore, when the surface of a document placed on a platen made of transparent glass is scanned while exposing it in a slit shape by an exposure unit from below, light reflected from the document is irradiated on a photosensitive material through a lens. Is simple and compact, and can be copied as if it were a copy. Also, in order to provide a reduction / enlargement function, the ratio of the optical path length from the original to the lens and from the lens to the photosensitive material can be changed, and the ratio between the scanning speed of the exposure unit and the feeding speed of the photosensitive material can be adjusted. It is.

[0003]

In such a copying camera, it is necessary to adjust the exposure amount according to the sensitivity of the photosensitive material. For example, if you want to reverse the black and white of a manuscript and make a block of white characters, use a negative sheet (reversed film) on the photosensitive material.
However, this negative sheet requires a much larger exposure than that of a positive sheet (normal film). Therefore, conventionally, the exposure time has been increased to increase the exposure amount. That is, the scanning speed of the exposure unit is reduced to increase the amount of exposure. Therefore, although the processing time becomes longer, if the magnification is not changed, it is necessary to slow down the feeding speed of the photosensitive material so as not to change the ratio with the scanning speed of the exposure unit. There is also a problem that becomes complicated.

Accordingly, the present invention provides a diffusion-transfer-type copying camera in which the amount of exposure can be adjusted very easily, regardless of whether a positive or negative sheet is used as a photosensitive material, and the processing time is not extended. The purpose is to do.

[0005]

In order to achieve the above object, the present invention is to expose a slit-shaped image of a document on a sheet-like photosensitive material, superimpose an image-receiving material on the exposed photosensitive material, and apply the image-receiving material to the photosensitive material. In a diffusion transfer type copying camera for transferring a recorded image to an image receiving material, a selection mode for switching the amount of radiation of a light source lamp is provided according to whether a photosensitive material to be used is a positive sheet or a negative sheet.

[0006]

In other words, even if the sensitivity is different by using either a positive sheet or a negative sheet as the photosensitive material, the light emission amount of the light source lamp is changed without changing the exposure time.
Since the switching is made in accordance with the scanning mode , there is no need to change the scanning speed of the exposure unit and the feeding speed of the photosensitive material. Therefore, the processing time is not extended, the operation is simple, and the exposure amount can be adjusted very easily.

[0007]

FIG. 1 conceptually shows a diffusion transfer type copying camera. In Figure 1, on the upper surface of the casing 10, for example up to A ₃ platen 11 clear glass of the document 50 can be mounted in size and is located, has become tabletop. An exposure unit 20 is arranged directly below the document table 11 so as to be movable at a variable speed V. The exposure unit 20 is a two-lamp type equipped with two tube-shaped light source lamps 21 each surrounded by a gutter-shaped mirror 22, and exposes the document 50 in a slit shape. M ₁ is disposed.
Thus, the exposure unit 20 Moving exposed by scanning the entire surface of the document 50, the reflected light of the document 50 is emitted horizontally in the mirror M _1. Here, the light source lamp 21 has a rated voltage of 100 V and a rated power consumption of 330 W. However, the casing 10 is provided with a mode selection button 13 so that the voltage applied to the light source lamp 21 can be, for example, two steps of 85 V and 66 V. The mode can be switched. That is, the amount of radiation of the light source lamp 21 is switched.
A selection mode is provided for the photosensitive material 60 described later.
Can be switched according to a positive sheet or a negative sheet .

The first mirror unit 31 and the second mirror unit 32 have a pair of plane mirrors M ₂ and M ₃ and a pair of plane mirrors M ₄ and M ₅ mounted on a roof at an angle of 45 °. The optical axis is disposed on both sides of the lens 40 in the horizontal direction. Accordingly, the lens optical reflection of the original 50 is reflected by the mirror M ₁ is reflected by the mirror M _2, M ₃ 40
Incident on the lens and exiting the lens 40 are reflected by mirrors M ₄ and M ₅
In reflected to form an image on the photosensitive member 60 further moves in the horizontal direction at a speed V ₀ is reflected by the plane mirror M _6. Here, the first mirror unit 31 moves in the same direction as the exposure unit 20 at a speed of 1/2 V, that is, half the speed of the exposure unit 20, and moves the original 50 with the movement of the exposure unit 20.
The optical path length from to the lens 40 does not change. The initial position of the first mirror unit 31 (position at which the movement starts) and the installation position of the second mirror unit 32 can be changed.
By changing the optical path length from 0 to the lens 40 and from the lens 40 to the photosensitive material 60, the reduction magnification can be set. However, the scaling factor in the direction perpendicular to the scanning of the exposure unit 20 can be set by changing the optical path length from the original 50 to the lens 40 and from the lens 40 to the photosensitive material 60. For the magnification, it is necessary to further adjust the ratio between the scanning speed V of the original 50 and the moving speed V ₀ of the photosensitive material 60. For this reason, the scanning speed V is changed in conjunction with the reduction / enlargement magnification, and the reduction / enlargement magnification in the scanning direction and the direction perpendicular to the scanning are made the same.

The photosensitive material 60 is obtained by attaching a photosensitive layer to the surface of a support made of paper or film. When exposed as described above, a latent image of the document 50 is formed on the photosensitive layer.
The photosensitive material 60 is contained in a magazine 61 in the form of a roll. The photosensitive material 60 is fed horizontally by a transport roller 63 and cut into a predetermined length by a cutter 62 to form a sheet. Then, as described above, the slit-shaped image of the original 50 is sequentially exposed on the sheet-shaped photosensitive material 60. Next, the image receiving material 70 is obtained by attaching an image receiving layer to the surface of a support made of paper or film, and is sent out from a magazine 71 by a transport roller 73. Then, the image receiving material 70 is overlapped with the exposed photosensitive material 60, enters the developing solution in the tray 80, and is pressed by the squeezing roller 81. In this developer, the latent image of the photosensitive layer is developed into blackened silver, while the unexposed portion of silver halide is converted into a water-soluble silver salt, and the image receiving material is exposed to light.
To the image receiving layer. Then, the silver salt in the image receiving layer is reduced by the developer to form a black silver image. In other words, the manuscript
The fifty images are copied on the image receiving material 70, and the image receiving material 70 and the photosensitive material 60 are taken out from the outlet 12.

However, in the case of normal copying without inverting the black and white of the image of the original 50, the non-inverting type photosensitive material 6
A positive sheet of 0 is used. However, since the photosensitive material 60 has high sensitivity, the mode selection button 13 is set to 66 V and copying is performed in the above-described procedure. Next, when copying the image of the original 50 by inverting the black and white, the inverting type photosensitive material 60 is used.
However, this photosensitive material 60 has a low sensitivity. For this reason, the mode selection button 13 is set to 85 V to increase the amount of radiation of the light source lamp 21. Therefore, the necessary exposure amount can be secured without lowering the scanning speed V of the exposure unit 20, and clear copying can be performed.

[0011]

As described above, in the diffusion transfer type copying camera of the present invention, the amount of radiation of the light source lamp is switched according to whether the photosensitive material to be used is a positive sheet or a negative sheet.
A selection mode is provided to allow the photosensitive material to be
Regardless of which negative sheet is used, the amount of radiation of the light source lamp is switched without changing the exposure time, so that the processing time does not increase, the operation is simple, and the exposure amount can be adjusted very easily. .

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a diffusion transfer type copying camera.

[Explanation of symbols]

 Reference Signs List 10 casing 11 platen 13 mode selection button 20 exposure unit 21 light source lamp 40 lens 50 document 60 photosensitive material 70 image receiving material

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 27/32 G03B 27/72

Claims (1)

(57) [Claims] 1. A diffusion transfer type copying camera for exposing a slit-shaped image of a document on a sheet-like photosensitive material, overlaying an image-receiving material on the exposed photosensitive material, and transferring an image recorded on the photosensitive material to the image-receiving material. In, depending on whether the photosensitive material used is a positive sheet or a negative sheet,
A copying camera having a selection mode for switching the amount of radiation of a light source lamp.