JPH0782202B2 - 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 copy document size detection device for automatically detecting a document size.

2. Description of the Related Art Conventionally, as a method of detecting the size of a document to be copied by a copying machine, the ADF is used to feed the document onto the platen glass surface, and the width when the document is set in the ADF There is a method of reading the length and 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. Further, since pre-scanning is required, for example, when automatic magnification selection such as automatically selecting a magnification suitable for copy paper after reading the document size, it takes a considerable amount of time before the regular copy operation starts. There is an inconvenience that it will take.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in the copying machine of the document size detection system as described above, the size of the thick document cannot be detected, the peripheral portion of the copy becomes dirty, and 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 irradiates light toward the platen glass below the optical system for scanning an original from the lower surface of the platen glass of the copying machine main body, and the platen A plurality of document size detectors that are always in an operating state while receiving reflected light from the document on the glass surface, and a discriminating unit that discriminates the document size from the signal read by the document size detector. Display means for displaying the document size discriminated by the discriminating means, a document table cover provided with an openable and closable white document pressing sheet covering the document table glass, and detecting that the document table cover is closed A switch and a start switch for making a copy operation of the main body of the copying machine are provided, and the document size detector constantly detects the size of the document on the platen glass surface and detects the detected document size. Is displayed on the display means, and when it is detected that the platen cover is closed, the discriminating means is a signal indicating the presence or absence of the document detected by the document size detector before and after closing the platen cover. In comparison with the above, the detection accuracy is improved by re-determining that the document exists at the detection location of the document size detector that is outputting the signal of no document when the platen cover is closed. When the start switch is operated without closing the platen cover, the copy operation is performed with the inaccurate original size discriminated from the signal of the original size detector at that time by the start switch operation signal. I am trying to move.

Effect of the Invention The present invention has the above-described configuration, without using an ADF, without coloring the platen cover or preliminarily scanning the optical system, the size of the document placed on the platen glass surface can be accurately and quickly read and judged. can do.

Further, since the document size is always detected even when the document cover is not closed, if the user places the document on the platen glass, the size is instantly and automatically determined. When the platen cover is closed, the size detection error that occurs in the case of a special document is prevented, and high-precision size detection is performed.

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 composed of a constant velocity unit 10 having a mirror 8 that moves from the left end to the right end of the original 4 integrally with an exposure lamp 7 and two mirrors 11 and 12 that move at half the speed of the constant velocity unit 10. It comprises a speed unit 13, a lens 14, and a mirror 15.

By scanning the constant speed unit 10 and the half speed unit 13, the original 4
Optical images are sequentially projected onto the photoconductor 5. Before the start of the copying operation, the constant speed unit 10 and the half speed unit 13 are at the origin position at the leftmost end in FIG. 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 the constant velocity unit 10 and the half velocity unit 13 scan the document 4.

Each original size detector 16 has a structure 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. The light from the light emitting element 17 is imaged on the part where the document 4 is on the platen glass 2 and is bright, and the bright part is imaged on the light receiving surface of the light receiving element 19. Produces an output signal. Since the light emitting element 17 and the light receiving element 19 are arranged so that the surfaces of the originals are in focus by the lenses 18 and 20, respectively, the output from the light receiving element 19 is large.

Since the characters and pictures are written in black on the document surface, the focus position
If the focus surface of 21 is too small, the black part will be misread as there is no original. In the embodiment of the present invention, the image forming area of the light emitting element is set to 5 mm to 10 mm in diameter, 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 table glass 2, the light receiving element 19 does not output.

The document size detector 16 includes a surface formed by the light emitting element and the optical axis of the light receiving element and the original so that the light emitted from the light emitting element 17 is not reflected by the lower surface of the platen 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 of the base glass 2.

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 whether or not there is a document on the upper surface of the document table glass 2.
If it is tilted more than 10 degrees, it will output about 8V when there is no original and 0V. If you tilt it further and tilt it more than 30 degrees, it will gradually drop from 8V if there is no document and 8V if there is no document. 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.
Four light-emitting elements 17 and light-receiving elements 19 are placed so that the focal points of the light-emitting element 17 and the light-receiving element 19 are located at the positions 23, 24, 25, and 26 shown in the figure, and the A3, A4, B4, B5 and A4 and B5 used in Japan are I am trying to distinguish between horizontal placement.

For simplification of explanation, the numbers of the document size detectors focused on FIGS. 23, 24, 25 and 26 in FIG. 4 are referred to as 23, 24, 25 and 26 as they are.

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.

The combination of the ○ mark and the X mark allows the vertical and horizontal sides of A3, A4, B4, B5 and A4, B5 to 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 cover. Further, the copying machine main body 1 has a switch 29 that operates when the document table cover 3 is completely closed and a hinge when the document table cover 3 is opened 30 ° from the platen glass surface.
There is a switch 30 that is pressed at one end of 27.

A case where a document of size B4, for example, is placed on the platen glass 2 to detect the size will be described.

Open the platen cover 3. In this state, the original size detector
Only 23 are working. 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, and 26 work, and in fact, 8 V output from each document size detector. On the other hand, the output of the document size detector 24 is 0V. In the embodiment of the present invention, since 4V is set as the threshold level for paper detection, the detection signal is ◯ for the document size detectors 23, 25, 26 as shown in the second stage of FIG. 5, and 24 is x. The paper size can be detected.

In the case of an original with fine characters written on general white paper, the original size can be detected correctly, but if there is a black photo etc. at the position corresponding to the original size detector 26, the original size will be detected. The output of the device 26 becomes, for example, 2 V, and the output becomes x, which may detect the B5 size. In order to solve this, in the embodiment of the present invention, the switch 29 and
30 is 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. Then close the platen cover completely and switch
When 29 works, read the output signal of each detector again. In the case of an original with a black photograph in the original size detector 26 at B4, as shown in FIG. 7, when the switch 30 first operates, a combination of ○ × ○ × is obtained, and then the switch 29 operates. The document size detector 24, which used to be X due to the absence of a document until now, detects the white sheet 28 of the document table cover 3 and changes to O. Other than that, it does not change because it is reading the manuscript.

Here, comparing the output signals of the document size detector with the switch 30 and the switch 29 in operation, it can be seen that the place where X changed 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 variable magnification mechanism 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 for 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, since the switch 29 is not closed, the operation such as paper size selection or magnification selection cannot be 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 the pressing. 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 23
The only reason is that only the originals are working and waiting for the original to be placed, and the original size detector 23 works and then the remaining detectors also work. Keeping the machine always operating consumes extra power for this purpose, and the user may leave the machine open with the platen cover 3 open. A device with a life of about 5 years, which is the life of the machine, is very expensive, so a long-life device corresponding to this is used only for the document size detector 23, and the remaining document size detector has a longer life. The cost of the copying machine is reduced by using a short light emitting element.

As described above in detail, according to the present invention, the switch for detecting the closing of the platen cover is provided, and the original size is detected by the start switch even when copying is performed without closing the platen cover. In this way, the original size can be detected reliably even for thin originals and hot originals such as books.

Conventionally, when detecting a document size with a copying machine, there is a limit to the document that can be detected, and only a sheet-like document can be detected, and even if a slightly thick document is possible, there is a limit to the thickness. In the embodiment of the present invention, as long as the document is placed on the platen glass, it can be detected at any thickness.

In particular, in the case of a thin original, the method of further improving the detection accuracy by closing the original cover and then comparing the signals is adopted to further increase the detection accuracy. Further, according to the present invention, since the original size is read even when the original cover is opened, if the original size is uncertain, once the original is placed on the original glass, the size is detected. Since it is displayed, it can be used for such size confirmation.

[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 ... Receiving light Element, 18, 20 ……
Lens, 29,30 ... Switch.

Claims (1)

[Claims] 1. An apparatus for irradiating light toward an original plate glass below an optical system for scanning an original from a lower surface of the original plate glass of a copying machine body, and receiving reflected light from the original on the original plate glass surface. In addition, a plurality of manuscript size detectors which are always in operation, a judging means for judging the manuscript size from the signals read by the manuscript size detector, and a display means for displaying the manuscript size judged by the judging means. A document table cover provided with an openable and closable white document pressing sheet for covering the document table glass, a switch for detecting that the document table cover is closed, and a start switch for making a copy operation of the copying machine body. The document size detector always detects the size of the document on the glass surface of the document table, displays the detected document size on the display means, and confirms that the document cover is closed. When it is detected that the document presence / absence is detected, the discriminating means compares the signals of presence / absence of the document detected by the document size detector before and after the document table cover is closed, and when the document table cover is closed, there is no document. The detection accuracy is improved by re-determining that the original is present at the detection location of the original size detector that is issuing a signal, and the start switch is operated without closing the original cover. At this time, the copying machine manuscript size detecting device is characterized in that the manuscript size detecting device shifts to the copying operation with the manuscript size not being highly accurate, which is discriminated from the signal of the manuscript size detector at that time by the signal of the start switch operation. .