JPS626105A - Original size detector for copying machine - Google Patents

Abstract

PURPOSE:To constitute the titled compact detector by providing plural photocouplers at a prescribed place so that the surface formed by the optical axes of a light emitting element and a photodetecting element is inclined by about 20 deg. with normal of original platen glass below the original platen glass. CONSTITUTION:Original size detectors 16 are fixed at plural places 23-26 below the original platen glass 2 on which an original 4 is put. Then, the detector 16 forms a spot with a diameter of 8mm on the underside of the original 4 with the light from the light emitting element 17 by a lens 18 and the reflected light is condensed on the photodetecting element 19 by a lens 20. Further, the light is projected slantingly so that the surface formed by the optical axes of the light emitting element 17 and the photodetecting element 19 is inclined by about 20 deg. with the normal of the original platen glass 2. As to the detectors 16, the presence or absence of the original is detected by the detector at the fist 23 position and when there is he original, the detector at other position is operated. hereby, the presence or absence and the size of the original can be detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic transfer type copying machine, and more particularly to a copying machine document size detection device that automatically detects the document size.

Conventional technology Conventionally, a method for detecting the size of an original to be copied using a copying machine is to use a multi-function DF to feed the original onto the glass surface of the original platen, and to measure the width of the original when the original is set on the multi-function DF. There is a method of detecting the document size by following the length. Another method is to attach a pale yellow or blue colored stripe or striped pattern to the document table cover that holds the document, and then perform a preliminary scan of the document before the optical system scans it for exposure. There is a method of reading a document using an optical sensor attached to an optical system.

The former method has the disadvantage that the dimensions of the document cannot be detected when copying a thick object such as a book without using a DF.

In the latter method, the color of the document cover is light and the color of the document cover is light so that even if the copy is made, the black color does not appear on the copied image. If it is placed on the back, the document table cover on the back will slide down and a black line will appear around the periphery.

In addition, because preliminary scanning is required, for example, when performing automatic magnification selection that automatically selects the magnification that matches the copy paper after reading the original size, it takes a considerable amount of time before the regular copying operation begins. There is an inconvenience that it takes a while.

Problems to be Solved by the Invention As mentioned above, copying machines that use the original size detection method described above cannot detect the size of thick originals, have dirt on the periphery of copies, and have problems with regular copies. The disadvantage is that it takes time to perform the exposure scan.

The present invention makes it possible to detect the size of a document regardless of whether it is a thick document or a thin document by a method described in detail later, and also prevents the copying image from becoming smudged and requires a long detection time. The object of the present invention is to provide a copying machine document size detection device that does not require a copying machine document size detection device.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a light emitting device which is provided below the optical system that scans the lower surface of the document table glass of the main body of the copying machine so as to irradiate light toward the document table glass. A plurality of document size detectors each consisting of an element, a lens, and a light-receiving element and a lens are provided to receive light reflected from the document on the document glass surface, and the light emitted from the light emitting element is detected on the bottom surface of the document glass platen. To prevent light from being reflected and entering the light receiving element, the surface formed by the optical axis of the light emitting element and the light receiving element is tilted at approximately 20 degrees with respect to the normal to the lower surface of the document table glass.

Effects of the present invention With the above-described structure, the size of the original placed on the glass surface of the document table can be accurately determined without using a DF or without the need for preliminary scanning of an optical system with a colored document table cover. and can read and judge quickly.

Example 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, reference numeral 1 denotes a main body of the copying machine, reference numeral 2 denotes a document table glass provided on the upper part of the copy machine main body, and reference numeral 3 denotes an openable and closable document table cover provided so as to cover the document table glass 2. As shown in FIG. A document 4 placed on the document table glass 2 is placed inside the lower side of the document table glass 2.
An optical system 6 is provided that scans and exposes the photoreceptor 5 to light. The optical system 6 includes a constant velocity unit 10 that includes an exposure lamp 7 and a mirror 8 that moves from the left edge to the right edge of the original 4.
and two mirrors 11 that move at the same speed as the constant velocity unit 10.
, 12, a half-speed unit 13, a lens 14, and a mirror 16.

As the constant speed unit 10 and the half speed unit 13 scan, the optical image of the original 4 is sequentially projected onto the photoreceptor 5. Before the start of the copy operation, the constant speed unit) 10 and the half speed unit 13
is located at the origin position at the leftmost end of FIG. Constant velocity unit 10
When the half-speed unit 13 scans the original 4, a plurality of original size detectors 16 are provided at positions that do not interfere with the movement of the original 4.

Each document size detector 16 has a configuration as shown in FIG. The light emitted from the light emitting element 17 passes through the lens, and the light emitting surface of the light emitting element 17 is imaged on the upper surface 21 of the document platen glass 2. The light-receiving element 19 is provided by the lens 20 so that the image of its light-receiving surface is formed at a focal point 21 where the previous image of the light-emitting surface is formed. The part where the original 4 is placed on the original table glass 2 becomes bright because the light from the light emitting element 17 forms an image, and the bright part is the part where the original 4 is placed on the light receiving element 19.
As a result, an output signal is output from the light receiving element 19. Since the light-emitting element 17 and the light-receiving element 19 are arranged so that the document surface is in focus with the lenses 18 and 20, respectively, the output from the light-receiving element 19 is large. Since characters and pictures are written in black on the document surface, if the screen that is in focus at the focal point position 21 is made too small, the black portions will be mistakenly read as there is no document. In the embodiment of the present invention, the imaging area of this light emitting element is 511M to 10M in diameter.
In particular, the optimum effect is obtained by setting the focal length of the lens, the positional relationship between the lens, the light-emitting surface, the light-receiving surface, and the document platen glass 2 so that it forms an 8'InII circle. Since the light from the light emitting element 17 passes through the portion where there is no original on the original table glass 2, there is no output to the light receiving element 19.

The document size detector 16 is installed between the surface formed by the optical axes of the light emitting element and the light receiving element and the original so that the light emitted from the light emitting element 17 does not reflect off the lower surface of the document platen glass 2 and enter the light receiving element 19 as it is. The base glass 2 is installed at an angle of 20 degrees with respect to the normal to the lower surface of the base glass 2, as shown in FIG.

When this angle is 0 degrees, the output of the light-receiving element is maximum, but the output itself is light reflected by the two surfaces of the document glass platen, so even if there is an original on the document glass platen 2, Even if it is not there, the output will not change. Therefore, it cannot be used to detect the document size. As this angle is gradually increased, the output from the light-receiving element 19 will decrease, but the output will differ depending on whether there is an original on the top surface of the original platen glass 2, and if it is tilted more than 10 degrees, the If OV is present, an output of about 8v will be output. If you tilt it further by more than 30 degrees, it will gradually drop from 8v if there is no document or if there is OV. As a result, in the embodiment of the present invention, the optimum angle of inclination is 20 degrees.

As described above, the document size detector 16 is mounted 9 overhanging the surface of the document table glass 20, and the light emitting elements 1 are located at positions 23, 24, 25, and 26 shown in FIG.
7 and the light receiving element 19 are arranged in such a way that the focal positions of the light receiving elements 19 and 3. M4. B4. A distinction is made between B5, Mu4, and B6 when placed horizontally.

To simplify the explanation, the numbers 23, 24 of the document size detectors that are in focus are the same as those shown in Figure 4, 23, 24, 25, and 26.
, 25, 26.

In FIG. 6, the detectors that produce output signals are marked with ○, and the detectors that do not produce signals are marked with X, corresponding to each document size. With this combination of O and X marks, 3. M4. Ba.

B6 and Mu4. You can distinguish between the vertical and horizontal sides of B6.

FIG. 6 is a side view of the copying machine main body 1, and the original platen glass 2
A white document holding sheet 28 is attached to the lower surface of the document table cover 3, which can be opened and closed using a hinge 27 as a fulcrum.

Further, the copying machine main body 1 operates when the document table cover 3 is completely closed. There are a switch 29 and a switch 30 that is pressed at one end of the hinge 27 when the document table cover 3 is opened 30 degrees from the document table glass surface.

A case will be described in which, for example, a B4 size document is placed on the document table glass 2 and its size is detected.

Open the document table cover 3. In this state, only the document size detector 23 is operating. Since there is nothing on the document table glass 2, the copying machine main body 1 naturally assumes that there is no document. Next B4
When a sheet of paper is placed, the original size detectors 23, 25, and 26 are activated, and an output of 8V is actually output from each original size detector. On the other hand, the output of the document size detector 24 is Ov. In the embodiment of the present invention, 4V is set as the threshold level for paper detection, so the detection signal is sent to the document size detector 23.25 as shown in the second row of FIG.
．． The paper size is detected as ○ for 26 and x for 24.

In the case of a document with fine text written on regular white paper, the document size can be detected correctly with this method, but if there is a black photograph, etc. at the position corresponding to the document size detector 26, the document size will be detected. The output of the device 26 is, for example, 2V,
The output may be x and 86 size may be detected. In order to solve this problem, in the embodiment of the present invention, the switch 2
9 and 3o are provided, and when the document table cover 3 is closed to 30 degrees from the glass surface, the output signals of the respective document size detectors are read. Next, when the document table cover is completely closed and the switch 29 is activated, the output signals of each detector are read again.

In the case of the original with a black photo on the original size detector 26 in step 84, as shown in FIG. 7, when the switch 30 is activated first, the combination of ○×○× is obtained, and then the switch 29 is activated. In some cases, the original size detector 24, which until now was marked x because there was no original, detects the white sheet 28 on the original platen cover 3 and changes to ○. Other than that, nothing changes because I am reading the manuscript.

Here, by comparing the output signals of the document size detector with switch 3o and switch 29 activated, it can be seen that the areas where the mark changes from x to ○ are originally the areas where there was no document and the outside was looked through the glass surface. .

Therefore, even if this document is mistakenly detected as B6 size when the document table cover 3 is open, the correct B4 size will eventually be detected.

In the embodiment of the present invention, the size of the original is detected and the appropriate copy paper is automatically selected according to the original size.
When the copy paper is kept constant, the magnification is automatically changed and the magnification input of the optical system of the copying machine is set so that the entire surface of the document fits on the entire surface of the copy paper. The paper size selection or magnification selection operation is started when the document table cover 3 is completely closed and the switch 29 is activated.

However, when copying a thick book or the like, copy without closing the document table cover 3. Therefore, switch 2
9 is never closed, so operations such as paper size selection or magnification selection cannot be started. In the embodiment of the present invention, when the copy start switch of the copying machine main body 1 is pressed without the switch 29 being closed, the paper size is determined based on the signal output from the document size detector 12 at the time the switch is pressed, and the paper size is determined. The selection or magnification selection operation is started.

Even after the copying operation is completed, until the document cover 3 is opened,
Continue to judge the same document size. Once the document table cover 3 is opened, the size determination described above will be performed again.

When opening the document platen cover 3, the document size detector 2 first
One of the reasons why the remaining detectors start working after the original size detector 23 is activated and the original size detector 23 is activated is to wait until the original is placed.
Leaving several light-emitting elements in constant operation consumes extra power, and the user may leave the equipment unattended with the document platen cover 3 open. Generally, a light-emitting element with a lifespan of about 6 years, which is the lifespan of a copying machine, would be very expensive, so an element with a corresponding long lifespan is used only for the document size detector 23.
The remaining document size detectors use light emitting elements with shorter lifetimes to reduce the cost of the copying machine.

Effects of the Invention As described in detail above, according to the present invention, the light emitted from the light emitting element is reflected from the surface of the document and enters the light receiver for detection, and the light reflected from the lower surface of the document table is not transmitted to the light receiver. To prevent them from entering, each of the multiple detectors is mounted at an angle.

As a result, all the mechanisms for detecting the document size are housed inside the main body of the copying machine, making it compact and highly reliable. Furthermore, the accuracy of document size detection is also high.

[Brief explanation 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, FIG. 4 is a layout diagram of the same detector, and FIG. The figure shows the correspondence of output signals corresponding to each document size of the detector, Figure 6 is a side view showing opening and closing of the document platen cover, and Figure 7 shows the case where size detection accuracy is increased by opening and closing the document platen cover. FIG. 2 is an explanatory diagram of an output signal of FIG. 1...Copier body, 2...Original platen glass, 3...Original platen cover, 4...Original, 6...Optics System, 16... Original size detector, 17... Light emitting element, 19 Old... Light receiving element, 18.20... Lens, 29°30...
····switch.

Claims (1)

[Claims] A light-emitting element and a lens are installed below the optical system that scans the lower surface of the document glass of the copying machine to irradiate light toward the document glass, and reflected light reflected from the original on the document glass surface. A plurality of document size detectors each including a light-receiving element and a lens for receiving light are provided, and the light-emitting element and A copying machine document size detection device characterized in that a surface formed by an optical axis of a light receiving element is inclined by 10 degrees to 30 degrees with respect to the normal line of the glass surface.