JPS59208537A - Exposing method - Google Patents

Abstract

PURPOSE:To record a picture having high contrast by controlling the illumination of a non-exposure surface in accordance with the transmission light quantity of an original at the time of exposure of one surface. CONSTITUTION:In case of exposing only one surface of an original, a mode is switched to a one surface mode, by which a light source 5 illuminates the surface of the original by brightness required for an exposure, and a light source 5' is turned on by the brightness corresponding to a transmission light quantity of the original and illuminates the surface of the original. That is to say, the light source 5' is controlled in accordance with an output of a photodetector 7, and when the transmission light quantity of the original is large, the light emitting quantity of the light source 5' is decreased, and when the transmission light quantity is small, the light emitting quantity of the light source 5' is increased. Also, in case of exposing the surface only, an optical path for projeting the rear side of the original of the original to a film is closed by a shutter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure method used in cameras, copying machines, facsimile machines, etc., which selectively exposes both sides or one side of a document to a photoreceptor.

In an exposure device of a recording device such as a copying machine that can record both sides of a sheet-like original, an illumination light source for the front side of the original and an illumination light source for the back side of the original are placed opposite each other on both sides of the original, and double-sided exposure is possible. Both light sources were turned on and both sides of the document were illuminated with almost the same brightness regardless of the time or single-sided exposure. Therefore, during single-sided exposure, if the light transmittance of the document is high, the transmitted light from the document will be projected onto the photoreceptor, reducing the contrast of the recorded image. In some cases, there is a problem in that images on both the front and back sides are recorded on the photoreceptor in an overlapping manner.

The present invention aims to solve the above-mentioned disadvantages, and is an exposure method that prevents a decrease in contrast and overlapping of recorded images by controlling a light source that illuminates the non-exposed surface according to the amount of transmitted light of the original during single-sided exposure. Therefore, regardless of the type of document, an appropriate recorded image can always be obtained.

The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a document conveying section and an illumination section of a rotary camera to which the present invention is applied, and FIG. 2 is a schematic diagram of an optical section of the camera.

In FIG. 1, a document P is fed into the camera through paper feeds o-yi, 1', and then detected by a light-receiving element 4 arranged in the illumination section. When the light-receiving element 4 detects the document, an image of the document is generated. Start exposing the film below. The document P that has entered the illumination section is illuminated on both the front and back sides by the document front side illumination light source 5 and the document back side illumination light source 5'. The illuminated images on both sides are projected onto a film F by a lens 13 via reflecting mirrors 10 and 10' and slits 11 and 11', which are arranged at an angle of 45 degrees with respect to the original, and a mirror 12. In FIGS. 1 and 2, a document P is fed by the paper feed rollers 1 and 1', and when the leading edge of the document P is detected by the light receiving element 4, the film F starts to move in the longitudinal direction and the shutter 16 opens. . Original P is on glass plate 3, 3'
When the film F is moved between the two, the film F moves in synchronization with the original, and the original image is exposed to the film F. When the document P moves further and its trailing edge comes off the light-receiving element, a timer (not shown) is activated, and the signal output from the timer when the trailing edge of the document P comes off the glass plates 3, 3' causes the film to be moved. F is stopped, the shutter 16 is closed, and the photographing is completed. At this time, the manuscript P
The moving speed of the film F and the moving speed of the film F are determined in advance by reduction determined by the optical path length and the lens. 6 is a lamp that illuminates the original, and 7 is a light receiving element that measures the amount of light transmitted through the original.

When exposing images on both sides of the original onto film, use light source 5.
, 5I, respectively, are turned on to illuminate both sides of the document. In the embodiment, both sides are illuminated with substantially the same brightness, but each side may be illuminated with individual brightness. When exposing only one side (front side) of the original, the mode is switched to single-sided mode, whereby the light source 5 illuminates the front side of the original with the brightness necessary for exposure, and the light source 5' illuminates the front side of the original with the brightness necessary for exposure. The light will turn on and illuminate the front surface of the document. That is, the light source 5' is controlled according to the output of the light receiving element 7, and when the amount of transmitted light from the document is large, the amount of light emitted from the light source 5' is decreased, and when the amount of transmitted light is small, the amount of light emitted from the light source 5' is increased. control.

When only the front side is exposed, the optical path for projecting the back side of the document onto the film is closed by a shutter.

In addition, when exposing only one side of the original, set the film F in a position different from that shown in Fig. 2 by replacing the unit of the camera unit as known in the art. It is also possible to make the exposure twice as large.

FIG. 6 shows an illumination light source control circuit, in which 30
31.31' is a voltage control circuit that controls the amount of light emitted by the light sources 5 and 51; 32 is an exposure mode changeover switch; 33
, 34 are display lamps. 7 is a light receiving element for measuring the amount of transmitted light of the original.

The illumination light source 5 for the front side of the document described above is composed of a plurality of lamps connected in series, and the illumination light source 5 for the back side of the document described above is composed of a plurality of lamps connected in series.
' consists of a plurality of lamps connected in series, and in the double-sided exposure mode, each lamp is turned on at a predetermined brightness by the voltage control circuit 31 when the document is sent to the illumination section. The exposure mode changeover switch 32 is not a manual switch, and when connected to the changeover switch 36 and υ, a, the double-sided exposure mode is set, and in conjunction with this, the illumination light source 5' is connected to the voltage control circuit 31. , and the lamp 33 lights up to display the double-sided exposure mode. On the other hand, when the switch 32 is connected to b, the single-sided exposure mode is set, and in conjunction with this, the illumination light source 5' is connected to the voltage control circuit 31', and the 2 lamp 34 is turned on to indicate the single-sided exposure mode.

Therefore, when the double-sided exposure mode is selected by the switch 32, both light sources 5.5' are connected to the same voltage control circuit 61.
When the single-sided mode is selected, the illumination light source 5' is controlled by the voltage control circuit 31' and is turned on according to the transmission density of the document. The voltage control circuit 31' reduces the amount of light emitted from the lamp 5' when the amount of transmitted light from the document detected by the light receiving element 7 is large, so that the image on the back side does not overlap with the image on the front side and is exposed on the film. Light the lamp 5' to increase the contrast of the image on the front side of the transmitted light, and if the amount of transmitted light from the original is low, increase the amount of light emitted by the lamp 5' to prevent the image on the back side from being exposed to the film. At the same time, the lamp 5' is turned on so that the transmitted light (the image on the front surface) is high. The amount of light emitted from the lamp 5' is controlled so that the total amount of light is emitted. The method for controlling the amount of illumination light is not limited to the embodiment, and may be controlled by providing a rim in front of the lamp, or the number of lamps to be lit may be controlled.

In the embodiment described above, recording is performed using a slit exposure method, but the document and the photoreceptor may be kept stationary and recording may be performed using a so-called full-surface simultaneous exposure method.

Furthermore, various known photoreceptors can be used, and for example, a photoelectric conversion element such as a COD:) insensor may be used. It can be applied to fax machines by using a line sensor.

As described above, according to the present invention, images on both sides of a document are less likely to be recorded in an overlapping manner during single-sided exposure, and images with high contrast can be recorded.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a rotary camera showing one embodiment of the present invention, FIG. 2 is a perspective view of the camera, and FIG. 3 is a diagram showing a light source control circuit. 5, 5' -- illumination light source, 10, 10', 12, 0 mirror, Po-original, 6... light intensity lamp, 7... light receiving element. Applicant Nakayanon Co., Ltd.

Claims (1)

[Claims] Device θ that selectively exposes both sides or one side of a document to a photoreceptor
In this method, a means for measuring the amount of light transmitted through the original is provided, and when both sides of the original are to be exposed, both sides of the original are illuminated with the brightness necessary for exposure and each is projected onto a photoreceptor, and when one side is to be exposed, the amount of light transmitted through the original is The method is characterized in that the surface to be exposed is illuminated with a brightness necessary for exposure, the surface not to be exposed is illuminated with a brightness controlled according to the output of the measuring means, and only the surface to be exposed is projected onto the photoreceptor. exposure method.