JPH0612246B2 - Copier Original size detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic transfer type copying machine, and more particularly to a copying machine document size detecting apparatus for automatically detecting a document size.

2. Description of the Related Art Conventionally, as a method of detecting the size of an original to be copied by a copying machine, the width and length of the original placed on the ADF are set so that the original is fed onto the glass platen of the original. There is a method of continuously detecting the document size. As another method, the entire surface of the original plate cover that holds the original document is colored in light yellow or blue, or a stripe pattern is attached, and the original document is pre-scanned before the optical system scans it for scanning. There is a method of reading an original with an optical sensor attached to an optical system.

The former method has a disadvantage that the size of the original cannot be detected when a thick material such as a book is copied without using the ADF.

In the latter method, although the original cover is lightly colored and the copied image is not blackened even when copied, when the copy is dark, the original is small or misaligned. If it is scratched, the original platen cover of the back will be transferred and a black line will appear in the peripheral portion. In addition, since pre-scanning is required, for example, when automatic magnification selection such as automatically selecting the magnification that matches the copy paper after reading the original size, it takes a considerable amount of time before the normal copy operation starts. There is an inconvenience that it will take time.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in a copying machine using the above-described document size detection method, the size of a thick document cannot be detected, the periphery of the copy is smeared, or the regular exposure scanning is performed. There is a drawback that it takes time to get to.

The present invention makes it possible to detect the size of a manuscript regardless of whether it is a thick manuscript or a thin manuscript by the method described in detail later, and the copy image does not become dirty and the detection time is not required. It is an object of the present invention to provide a document size detecting device for a copying machine.

Means for Solving the Problems In order to solve the above problems, the present invention provides a light emission provided below the optical system for scanning the lower surface of the platen glass of the copying machine body so as to irradiate the platen glass with light. A plurality of document size detectors consisting of a light receiving element and a lens for receiving the reflected light reflected from the document on the glass platen surface of the platen glass are provided. The surface formed by the optical axes of the light emitting element and the light receiving element is inclined by about 20 degrees with respect to the normal line of the lower surface of the platen glass so that the light is not reflected and does not enter the light receiving element.

Operation With the above-described configuration, the present invention can accurately and quickly determine the size of the document placed on the platen glass surface without using the ADF, coloring the platen cover, or pre-scanning the optical system. Can be read and judged.

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

FIG. 1 is a schematic sectional view of a copying machine according to the present invention. In the figure, 1 is a copying machine main body, 2 is a document table glass provided on the upper portion of the copying machine body, and 3 is an openable / closable document table cover provided so as to cover the document table glass 2. Inside the lower side of the platen glass 2, a document 4 placed on the platen glass 2 is placed.
An optical system 6 is provided for scanning and exposing the photoconductor 5. The optical system 6 is a constant velocity unit 10 including a mirror 8 that moves from the left end to the right end of the document 4 integrally with the exposure lamp 7.
And two mirrors 1 that move at half the speed of the constant velocity unit 10
A half-speed unit 13 and a lens 14 composed of 1, 12;
It consists of a mirror 15. By scanning the constant speed unit 10 and the half speed unit 13, the optical image of the original 4 is sequentially projected onto the photoconductor 5. Prior to the start of the copying operation, the constant speed unit 10 and the half speed unit 13 are at the leftmost origin position in FIG. Constant speed unit 10 and half speed unit 13
A plurality of document size detectors 16 are provided at positions in a direction that does not interfere with the movement of the document 4 when scanning the document 4.

Each original size detector 16 is constructed as shown in FIG. The light emitted from the light emitting element 17 passes through the lens and an image is formed on the light emitting surface of the light emitting element 17 on the upper surface 21 of the original platen glass 2. The light receiving element 19 is provided so that the image of the light receiving surface of the light receiving element 19 is formed by the lens 20 at the focal position 21 where the image of the previous light emitting surface is formed. Document 4 on platen glass 2
The light from the light emitting element 17 is imaged at a certain portion and is bright, and as a result of the bright portion being imaged on the light receiving surface of the light receiving element 19, an output signal is output from the light receiving element 19. The light emitting element 17 and the light receiving element 19 are the lens 1 respectively.
Since the document surfaces 8 and 20 are arranged so as to be in focus on the document surface, a large output is obtained from the light receiving element 19. Since the characters and pictures are written in black on the document surface, if the focused screen at the focus position 21 is made too small, the black portion will be misread as the document does not exist. In the embodiment of the present invention, the image forming area of the light emitting element is set to a diameter of 5 mm to 10 mm, and the focal length of the lens, the positional relationship between the lens and the light emitting surface and the light receiving surface, and the platen glass 2 are set so as to have a circular shape of 8 mm. By doing so, the optimum effect is obtained. Since the light from the light emitting element 17 passes through a portion where there is no original on the original glass 2, the light receiving element 19 does not output.

The document size detector 16 and the document formed by the optical axes of the light emitting element and the light receiving element are arranged so that the light emitted from the light emitting element 17 is not reflected by the lower surface of the original table glass 2 and directly enters the light receiving element 19. As shown in FIG. 3, the base glass 2 is attached at an angle of 20 degrees with respect to the normal line to the lower surface.

When this angle is 0 degree, the output of the light receiving element becomes maximum, but the output itself is the light reflected by the surface of the platen glass 2 and even if an original is placed on the platen glass 2. The output does not change even if it does not exist. Therefore, it cannot be used to detect the document size. If this angle is gradually increased, the output from the light receiving element 19 will decrease, but there will be a difference in output depending on the presence or absence of a document on the upper surface of the document table glass 2, and if there is no document when tilted 10 degrees or more, When it is 0V, the output of about 8V comes out. When it is further tilted at an angle of 30 degrees or more, when there is no document, 0 V is applied and it gradually drops from 8 V. As a result, in the embodiment of the present invention, the angle of this inclination is optimally 20 degrees.

As described above, the document size detector 16 is attached to the surface of the document table glass 2 by bending it, but the light emitting element 1 is placed at the positions 23, 24, 25 and 26 shown in FIG.
7 and the light-receiving element 19 are arranged so that the focal points of the light-receiving element 19 and the light-receiving element 19 are located to distinguish between A3, A4, B4, B5 and A4 and B5 which are used in Japan.

For simplification of description, the numbers of the document size detectors focusing on FIGS.
Called 4, 25, 26.

In FIG. 5, detectors that output an output signal corresponding to each document size are indicated by a circle, and detectors that do not output are indicated by a cross. With this combination of ◯ and ×, A3, A4, B4, B5 and A4, B5
Vertical and horizontal can be distinguished.

FIG. 6 is a side view of the main body 1 of the copying machine.
A white original pressing sheet 28 is attached to the lower surface of the original plate cover 3 which can be opened and closed with a hinge 27 as a fulcrum so as to cover the. Further, the copying machine body 1 operates when the original plate cover 3 is completely closed. Switch 2
9 and a switch 30 which is pressed by one end of the bulge 27 when the platen cover 3 is opened 30 ° from the platen glass surface. A case will be described where the size of a document of size B4 placed on the platen glass 2 is detected. Open the platen cover 3. In this state, only the document size detector 23 is operating. Since there is nothing on the platen glass 2, it is assumed that the copying machine body 1 has no original. Next, when B4 paper is placed, the document size detectors 23, 25, 26 are activated,
Actually, the output of 8V is output from the document size detector. On the other hand, the output of the document size detector 24 is 0V.
Is. In the embodiment of the present invention, 4V is set as the threshold level for paper detection, and therefore the detection signals are as shown in the second stage of FIG.
◯, and 24 becomes x, and the paper size can be detected.

In the case of a manuscript in which fine characters are written on a general white paper, the size of the manuscript can be correctly detected, but if there is a black photograph at the position corresponding to the manuscript size detector 26, the manuscript size is detected. The output of the device 26 is, for example, 2V,
The output may be X, and the B5 size may be detected. In order to solve this, the switch 2 is used in the embodiment of the present invention.
9 and 30 are provided, and first, when the document table cover 3 is closed up to 30 ° from the glass surface, the output signal of each document size detector is read. Next, when the document table cover is completely closed and the switch 29 is activated, the output signals of the respective detectors are read again. In the case of a document with a black photograph in the document size detector 26 at B4, as shown in FIG. 7, when the switch 30 first operates, the combination becomes XX and then the switch 29 operates. Sometimes the original size detector 24, which used to be X because there is no original, detects the white sheet 28 of the original plate cover 3, and changes to O. Other than that, it does not change because it is reading the manuscript.

Here, the output signals of the document size detector with the switch 30 and the switch 29 in operation are compared, and it can be seen that the place where x changes to ◯ is the place where there was no original and the outside was seen through the glass surface. . Therefore, even if the original is mistakenly detected as the B5 size when the original cover 3 is opened, the correct B4 size can be finally detected.

In the embodiment of the present invention, the size of the original is detected, and a copy sheet suitable for the original size is automatically selected,
When the copy paper is kept constant, the magnification is automatically converted and the magnification input of the optical system of the copying machine is set so that the entire surface of the original is placed on the entire copy paper. The operation of selecting the paper size or the magnification is started when the document table cover 3 is completely closed and the switch 29 is operated.

However, when a thick book or the like is to be copied, the original plate cover 3 is not closed and the copy is performed. Therefore, switch 2
Since 9 is not closed, the operation for selecting the paper size or the magnification is not entered. In the embodiment of the present invention, when the copy start switch of the copying machine body 1 is pressed without the switch 29 being closed, the paper size is judged by the signal output from the document size detector 12 at the time of pressing the paper size. The operation of selection or magnification selection is entered.

Even after the copy operation is completed, until the platen cover 3 is opened,
Continue to judge the same original size. Once the platen cover 3 is opened, the size determination described above is performed again.
When the platen cover 3 is opened, first the document size detector 2
One of the reasons why only 3 is operating and waiting for the document to be placed, and that the document size detector 23 works and then the remaining detectors also work is as follows.
Keeping some of the light-emitting elements always in operation consumes extra power for this purpose, and the user may leave the equipment with the platen cover 3 open. Generally, a light emitting element having a life of about 5 years, which is the life of a copying machine, is very expensive. Therefore, a long-life element corresponding to this is used only for the document size detector 23.
The remaining document size detector uses light emitting elements with shorter lifespan to reduce the cost of the copying machine.

As described in detail above, according to the present invention, the light emitted from the light emitting element is reflected by the document surface and enters the light receiver for detection, and the light reflected by the lower surface of the document table is not received by the light receiver. In order to prevent it from entering, each of the plurality of detectors is mounted by tilting.

As a result, the mechanism for detecting the size of the original is all contained in the main body of the copying machine, which is compact and highly reliable. Further, the accuracy of detecting the document size is also high.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a copying machine according to an embodiment of the present invention, FIGS. 2 and 3 are sectional views of a document size detector of the present invention, and FIG. 4 is a layout diagram of the same detector. FIG. 6 is a correspondence diagram of output signals corresponding to respective document sizes of the detector, FIG. 6 is a side view showing opening and closing of the document table cover, and FIG. 7 is a case where size detection accuracy is improved by opening and closing the document table cover. It is explanatory drawing of an output signal. 1 ... Copying machine main body, 2 ... Original platen glass, 3 ... Original platen cover, 4 ... Original, 6 ... Optical system, 16 ... Original size detector, 17 ... Light emitting element, 19 ... Light receiving Element, 1
8, 20 ... Lens, 29, 30 ... Switch.

Claims (1)

[Claims] 1. A light-emitting element and a lens provided below the optical system for scanning the lower surface of the platen glass of the copying machine body so as to irradiate light toward the platen glass, and a document on the platen glass surface. Providing a plurality of document size detectors consisting of a light receiving element and a lens for receiving the reflected light so that the light emitted from the light emitting element will not be reflected on the lower surface of the platen glass and enter the light receiving element. A document size detecting apparatus for a copying machine, wherein surfaces formed by the optical axes of the light emitting element and the light receiving element are tilted by 10 to 30 degrees with respect to the glass surface normal.