JPS626243A - Original size detecting device for copying machine - Google Patents

Abstract

PURPOSE:To detect the size of an original securely without reference to its thickness by providing a switch which detects an original platen cover being closed and putting original size detection into effect with a start switch even when a copy is taken without closing the original platen cover. CONSTITUTION:Plural original size detectors 16 which irradiate light to the original platen glass 2 and receive reflected light from the original on the original platen glass 2, the original platen cover 3 which is opened and closed to cover the original platen cover 2, a switch for detecting the closure of the original platen cover 3, and the start switch for putting a copying machine in copying operation are provided under an optical system which scans the reverse surface of the original platen glass 2 and the copying machine body 1. The original size is detected by the operation of the switch for detecting the closure of the original platen cover and when the start switch is operated while said switch is not is operation, the original size is detected with a signal indicating the operation of the start switch.

Description

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

Conventional technology The conventional 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 original platen glass surface, and then measure the width of the original when it is set on the ADF. There is a method to detect the document size by reading the length. Another method is to paint the entire surface of the document table cover that holds the document in pale yellow or blue, or add a striped pattern, 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 size 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 fall down and a black line will appear around the periphery.

Preliminary scanning is still required, so if you use automatic magnification selection, for example, which automatically selects the magnification that matches the copy paper after reading the original size, it will take a considerable amount of time to start the normal copying operation. There is an inconvenience that this may occur.

Problems to be Solved by the Invention As mentioned above, copying machines using the original size detection method cannot detect the size of thick originals, stains appear on the periphery of copies, and problems occur when exposure is incorrect. The disadvantage is that it takes time to 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 irradiates light toward the bottom of the scanning optical system on the lower surface of the document glass of the copying machine body toward the document glass surface. a plurality of original size detectors adapted to receive reflected light from the originals; an openable and closable original glass cover that covers the original glass; a switch that detects when the original glass cover is closed; A start switch is provided for starting the copying operation of the machine body, and the document size is detected by the operation of the switch that detects that the document table cover is closed.
When the start switch is activated while the switch is not activated, the document size is detected based on the activation signal of the start switch.

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

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 6 to light. The optical system 6 is a constant velocity unit 1o equipped with 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 and a lens 14. ′
It consists of a mirror 16.

Constant velocity unit 10. As the half-speed unit 13 scans, optical images of the original 4 are sequentially projected onto the photoreceptor 5. Before starting 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 1o
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 a lens, and the light emitting surface of the light emitting element 17 is imaged on the upper surface 21 of the document table glass 2. The light-receiving element 19 is provided so that the image of its light-receiving surface is formed by a lens 20 at a focal position 21 where the image of the previous light-emitting surface is formed. Original 4 is placed on the original platen glass 2.
A certain part becomes bright because the light from the light emitting element 17 forms an image, and as a result, the bright part forms an image on the light receiving surface of the light receiving element 19, and as a result, an output signal is output from the light receiving element 19. Light emitting element 17. Since the light-receiving elements 19 are arranged in such a manner that they can be focused on the document surface by lenses 18 and 20, the output from the light-receiving elements 19 is large.

Since characters and pictures are written in black on the document surface, if the surface that is in focus at the focal point position 21 is made too small, the black portion will be mistakenly read as not being a document.

In the embodiment of the present invention, the imaging area of the light emitting element is set to be 6 mm to 10 mm in diameter, and in particular, the focal length of the lens is adjusted to form a circle of 8 mm, and the positional relationship between the lens, the light emitting surface, the light receiving surface, and the document platen glass 2 is adjusted. The optimal effect is obtained by setting .

The light emitting element 17 is illuminated in the area where there is no original on the original table glass 2.
Since the light passes through, 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 attached 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 go down from 8V if there is an Ov if there is no document. 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 obliquely to the surface of the document table glass 2, but the light emitting element 1 is located at 23, 24, 25° 26 as 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. A4. B4. B.5
Also, I try to distinguish between the horizontal position of person 4 and person B5.

Figure 4 23.24.25 for simplification of explanation.

Change the number of the original size detector that focuses on 26 to 2.
They are called 3.24 and 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 the combination of O mark and × mark, 3. M4, B4.

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.

The copying machine body 1 also includes a switch 29 that is activated when the document table cover 3 is completely closed, and a switch 3o that is pressed at one end of the hinge 27 when the document table cover 3 is opened 30' from the document table glass surface. be.

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 suddenly assumes that there is no document. Next 84
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 original size detector 24 is Ov.

In the embodiment of the present invention, 4V is set as the paper detection threshold level, so the detection signal is ○ for the document size detectors 23, 25, and 26, and × for 24, as shown in the second row of Fig. 6. The paper size can be detected.

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 cannot be detected. The output of the device 26 is, for example, 2V,
The output may be x and B6 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 a B4 original with a black photo in the area of the original size detector 26, as shown in FIG. 7, when the switch 30 is activated first, the combination of ○×○× is not activated, and then the switch 29 is activated. When the document size detector 24 detects the white sheet 28 on the document platen cover 3, the document size detector 24, which until now was marked "X" because there is no document, changes to "○" because it detects the white sheet 28 on the document table cover 3. 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 system detects the size of the original and automatically selects the appropriate copy paper according to the original size.
When copying paper is kept constant, the magnification changing mechanism of the copying machine optical system is set so that the magnification is automatically changed so that the entire surface of the document fits on the entire surface of the copying 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 29
Since it is never closed, operations such as paper size selection or magnification selection cannot be started. In the embodiment of the present invention, when the copy start switch on 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 29 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
The reason why only the detector 3 is activated and the remaining detectors start working after the original size detector 23 is activated is to wait for the document to be placed or not. Keeping the light-emitting element of the machine in constant operation consumes extra power, and although the user may leave the machine unattended with the document platen cover 3 open, generally the light-emitting element does not emit light. Elements with a lifespan of about 5 years, which is the lifespan of a copying machine, would be very expensive, so a long-life element corresponding to this element is used only in the document size detector 23, and is not used in the remaining document size detectors. Efforts are being made to lower the cost of copying machines by using light-emitting elements with shorter lifetimes.

Effects of the Invention As detailed above, according to the present invention, a switch is provided to detect when the document tray cover is closed, and the document size can be detected using the start switch even when copying is performed without closing the document tray cover. The size of the original can be reliably detected, even if the original is thin or thick, such as a book.

Conventionally, when detecting the size of an original using a copying machine, there are limitations on the types of originals that can be detected.Only sheet originals can be detected, and even if slightly thicker originals can be detected, there are limitations on the thickness. In the embodiment of the present invention, it is possible to detect a document of any thickness as long as it can be placed on the document table glass.

In particular, in the case of thin originals, a method is adopted in which signals are further compared after the document table cover is closed to further improve detection accuracy. Furthermore, since the present invention uses a method to read the document size even when the document glass cover is open, if you are unsure of the document size, simply place the document on the document glass and the size will be detected. Since it is displayed, it can also be used for size confirmation like this.

[Brief explanation of the drawing]

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 between the output signals of the detector for each document size, Figure 6 is a side view showing the 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. 3 is an explanatory diagram of an output signal. 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... Light receiving element, 18.20... Lens, 29°30... Switch. Name of agent: Patent attorney Toshio Nakao and one other person
3 Figure 4 1A

Claims (1)

[Claims] A plurality of originals that is configured to emit light toward the original glass below the optical system that scans the originals on the lower surface of the original glass of the copying machine, and to receive light reflected from the originals on the original glass. A size detector, an openable and closable document table cover that covers the document table glass, a switch for detecting that the document table cover is closed, and a start switch for causing the copying machine main body to perform a copying operation are provided. The document size is detected by the activation of the switch that detects that the document platen cover is closed, and when the start switch is activated while the above switch is not activated, the document size is detected by the activation signal of the start switch. A copying machine original size detection device characterized in that: