JPH0833577B2 - Automatic exposure equipment for copiers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic exposure apparatus applied to a copying machine or the like, and in particular, by performing feature extraction of an image or a character described on a subject, The present invention relates to an automatic exposure device for a copying machine that performs copying under optimum copying conditions based on various information such as characters, pictures and photographs.

[Prior art]

In a conventional copying machine, a subject (a manuscript, etc.) that contains a lot of high-contrast information such as a character or a graph is distinguished from a subject that contains many halftones, such as a photograph or a printed matter, and the characteristics of each are distinguished. Attempts have been made to make clearer copies by processing according to the difference.

For this reason, photometry (prescanning) is performed in advance before copying an original to obtain image information, and then exposure is performed by reading scanning in a continuous process subsequent to this photometry. When photometrically measuring the document in advance, the document and the slit are moved relative to each other for scanning, and the light from the document is focused on the detection sensor.

By the way, the photometric area by the detection sensor is, for example, the second area.
As shown in the drawing, the vicinity of the center along the moving direction of the slit 58 of the document table 14 is set as a photometric area. This is provided in consideration of the fact that most of the originals are E size or larger in the photograph, and is assumed to be less affected by the reflected light from the original pressing plate and to extract many features of the originals.

(Problems to be Solved by the Invention) However, in some documents, the main part thereof may not be clearly metered. For example, this is a case where the main pattern is arranged in the peripheral portion of the document. Also,
Particularly in a color copying machine, there is a special application in which it is desired to set a color or density based on a part of an image outside the photometric area.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an automatic exposure apparatus capable of reducing defects in photometry, improving functions, and performing clear copying.

(Means and Actions for Solving the Object) That is, the above-mentioned object of the present invention is to scan light from a light source onto a document placed on a document table, perform photometry by the first scanning, and In an automatic exposure apparatus of a copying machine that performs exposure by scanning the scanning, a fully automatic exposure mode in which an original is placed on an original table and the first scanning and the second scanning are continuously performed,
A switching unit capable of arbitrarily selecting a semi-automatic exposure mode in which the document is placed at a desired position on the document table, the first scanning is performed, the document is moved to a predetermined position, and then the second scanning is performed. And an automatic exposure device of a copying machine.

Since a fully automatic exposure mode in which photometric scanning and exposure scanning are continuous and a non-continuous semi-automatic exposure mode in which photometric scanning and exposure scanning are separated, for example, in the case of a document whose main part is out of the photometric area, , The semi-automatic exposure mode is selected, the main portion is arranged so as to be in the photometric region, and after the photometry, the document is relocated to the standard exposure position and the exposure scanning can be restarted.

Embodiment An embodiment of the automatic exposure apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of a silver salt photographic color copying machine 12 to which an automatic exposure device for a copying machine according to the present invention is applied.

As shown in FIG. 1, the color document 16 is placed on the transparent document table 14 with the document surface facing down. The color original 16 is pressed from above by an original pressing plate 18 having a white lower surface. Further, a white standard plate 20 is attached to the lower surface of the document table 14 at the left end, and by measuring the reflected light, changes with time of the light source and the color filter are corrected.

The light source unit 22 includes a light source 24, a reflector 26, and a mirror 28.
The color original 16 is slit-illuminated by reciprocating in parallel with the original table 14. The mirror unit 30 holds two mirrors 32 and 34 extending in a direction perpendicular to the plane of the drawing, and returns the light from the light source unit 22 in parallel. Also,
The mirror unit 30 moves in the direction of the arrow when converting the magnification.

The lens unit 36 moves in the direction of the arrow when converting the magnification. In this lens unit 36, a yellow filter Y, a magenta filter M, and a cyan filter C are arranged between a front lens group 38 and a rear lens group 40. These color filters Y, M, and C are movable in a direction orthogonal to the optical axis, and the quality of slit light is adjusted by the insertion amount to correct the color balance. Further, behind the rear group 40, two diaphragm plates 42 and 44 which move in mutually opposite directions are arranged.

The light passing through the lens unit 36 reaches an optical path switching mirror 48 having a shaft 46 as a rotation center. During the prescan, the optical path switching mirror 48 moves into the optical path as shown by the solid line, and the reflected light from the color original 16 is condensed by the condensing lens arranged in the image forming plane in the photometric device 10 and irradiated on the sensor. To do.

The automatic exposure apparatus according to the present invention includes the photometric device 10 and a transport system and a control system for guiding the photosensitive material 62 to the exposure position.

As shown in FIG. 3, a mirror 50 for guiding the reflected light from the color original 16 reflected by the optical path switching mirror 48 in a direction substantially horizontal to the color original is disposed in the photometric device 10. A condenser lens 52 arranged on the image plane is arranged in front of the mirror 50, and a diffusion plate 54 is arranged in front of it.

A Fresnel lens is used as the condenser lens 52, and the slit light from the color original 16 is condensed and put into the diffusion plate 54. The diffusion plate 54 is made of, for example, ground glass and diffuses the condensed slit light. The diffused slit light is incident on the sensor unit 56 which is a photometric means.

The condenser lens 52 is arranged around the optical axis, and the width of the light incident on the condenser lens 52 is not affected by the reflected light from the document holding plate 18, and many features of the document are extracted.
It is about 10cm. That is, the photometric area shown on the document table 14 is an area along the moving direction of the slit 58 substantially corresponding to the width of the photometric device 10, as indicated by a broken line frame 70 in the plan view of the copying machine in FIG. The reference position of the color original document 16 placed on the original document table 14 is set to a position shown in the figure such that the photometric area 70 is near the center when the normal fully automatic exposure mode described later is selected.

Returning to FIG. 1, the photosensitive material 62 is stored in the magazine 60 in a rolled state. The photosensitive material 62 is pulled out from the magazine 60 for a certain length and then cut by a cutter (not shown), and stopped at a position where its tip end is sandwiched by the pair of rollers 64 and 66. A pair of rollers facing the pair of rollers 64 and 66.
68 and 69 are arranged, a slit exposure position is formed between these four roller pairs, and light from the lens unit 36 enters.

The photosensitive material 62 exposed by the light from the lens unit 36 is developed, bleached and fixed by a processing unit (not shown) after the exposure.
Each process of washing with water is performed, and after drying, it is sent out onto a take-out tray (not shown).

Next, the control system of the exposure apparatus of the present invention will be described. FIG. 4 is a schematic block diagram showing the control system of the exposure apparatus of the copying machine. The control unit 80 of this control system controls the lighting of the light source 24 based on an instruction from the console 90, and the light source unit.
The movement control of 22 and the mirror unit 30 and the lens unit 36, the insertion amount of the color filters Y, M and C into the optical path and the position control of the diaphragm plates 42 and 44, the position control of the optical path switching mirror 48, and the photosensitive material 62. The transport drive system 100 is controlled.

The control system will be described with reference to FIG. 5 together with the operation of the exposure apparatus.

After the color original 16 to be copied is placed at the standard position on the original table 14 and pressed by the original pressing plate 18, when the operator instructs the console 90 to start copying, the control unit
Reference numeral 80 executes feeding of the photosensitive material 62 and start of prescan. At this time, if the operator operates the changeover switch 91 (see FIG. 4) on the console to select the fully automatic exposure mode, the operations described below are executed as a series of continuous operations. First, the control unit 80 controls the document illuminated by the light source 24 and the slit (a predetermined area formed on the document table 14).
A pre-scan is performed by the first scan in which and are relatively moved. Therefore, the control unit 80 controls the optical path switching mirror 48
(See FIG. 1) into the optical path, and the diaphragm plates 42, 44
Is set at the standard position, and the reflected light from the color original 16 is guided into the photometric device 10 for measurement. The measurement of the color original, which is performed during the relative movement of the original and the slit, is intermittently performed with a cycle, and the result is amplified by the amplifier 63 and then the A / D converter 66 as shown in FIG. Will be digitized in. The digitized photometric data is supplied to the microcomputer 67 and is compared with the reference signal stored in the microcomputer to calculate the optimum color and density. Further, the microcomputer 67 calculates the replenishment amount of the developer. The control unit 80 controls copying conditions such as a color filter, an exposure amount, a charge amount, and a developing bias amount based on these calculation results. When the pre-scan ends, the control unit 80 retracts the optical path switching mirror 48 from the optical path and re-moves the light source unit 22 that has moved back and returned to the initial position to perform the second scanning.
Thereby, the reflected light of the original 16 is projected on the surface of the photosensitive material 62 to expose the photosensitive material. When one exposure is completed, the control unit
The reference numeral 80 conveys the photosensitive material 62 in synchronization with the movement of the light source unit 22, and then repeats the above-mentioned operation based on an instruction from the console 90 to expose a predetermined number of photosensitive materials.

Next, when the changeover switch 91 on the console 90 is changed over and the semi-automatic exposure mode is selected,
A description will be given with reference to FIGS. 6 and 7. In this case, the pre-scan is the same as the fully automatic exposure mode shown in FIG. However, when this mode is selected, the prescan and the exposure operation can be temporarily interrupted, so that the operator first puts the original 16 so that the main part of the color original 16 comes into the photometric area 70, as shown in FIG. Is placed on the document table 14. In the figure, the main part shown by the shaded area is located at the lower side of the document, and therefore the document is moved to a position above the paper surface for prescanning. After the completion of the prescan by the first scan, the operator returns the original document to the standard position again. That is, after moving the original 16 to the lower position shown on the paper and setting it at the central position of the original table, the operator issues a command from the console 90,
A second scan is performed to perform the exposure operation. The following operation is the same as the fully automatic exposure mode.

(Effects of the Invention) As described above, according to the automatic exposure apparatus of the present invention, since the semi-automatic exposure mode in which the prescan and the exposure operation can be performed separately is provided, the main part of the document is moved to the photometric area. It is possible to perform photometry, so that even if the document is a document whose main portion is off the center of the document, suitable photometry can be performed, and preferable copying is performed by image exposure.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a silver salt photographic color copying machine to which an embodiment of the present invention is applied, FIG. 2 is a plan view of the copying machine for explaining a fully automatic exposure mode, and FIG. 4 is a block diagram for explaining the control system, FIGS. 5 and 6 are flowcharts for explaining the operation of the control system, and FIG. 7 is for explaining the semi-complete exposure mode. FIG. 3 is a plan view of a copying machine for carrying out. 10 ... Photometer of copy machine, 14 ... Platen, 16 ... Color original, 48 ... Optical path switching mirror, 70 ... Photometric area, 80 ...
… Control unit, 90… Console, 91… Changeover switch,
100: Transport drive system

Claims (1)

[Claims] 1. An automatic exposure apparatus for a copying machine, wherein light from a light source is scanned on a document placed on a document table, photometry is performed by a first scan, and exposure is performed by a second scan. A fully automatic exposure mode in which a document is placed on the table and the first scanning and the second scanning are continuously performed, and a document is placed in a desired position on the document table and the first scanning is performed. An automatic exposure apparatus for a copying machine, which has a switching means capable of arbitrarily selecting a semi-automatic exposure mode in which a rear original is moved to a predetermined position and then a second scanning is performed.