JPS626241A - Original size detecting device for copying machine - Google Patents

Abstract

PURPOSE:To improve the precision of size detection by detecting original size by plural detectors while an original platen cover is open, and further closing the original platen cover. CONSTITUTION:Plural original size detectors 16 which each consist of a light emitting element 17 for irradiating light to original platen glass 2, a photodetecting element 19 for light receiving reflected light from a lens and an original on the original platen glass, and lenses 18 and 20, the original platen cover 3 which is opened and closed to cover the original platen glass 2, the 1st switch which detects the opening state of the original platen cover 2 from the opening/closing operation of the original platen cover 3, and the 2nd switch which detects the complete closing state are provided under an optical system which makes a scan on the reverse surface of the original platen glass 2 of a copying machine body 1. Then, signals of said detectors when the 1st switch is in operation are compared with those when the 2nd switch is in operation and it is judged that the original is not present where a signal is inverted, thus detecting the size of the original.

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.

2. Description of the Related Art 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 document table. There is a method to detect the document size by reading the width and length. Another method is to color 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 processor 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 taken into account so that even if the copy is made, the black color does not appear on the copied image. If the original platen cover on the back is tilted, a black line will appear around the periphery.

In addition, because preliminary scanning is required, it takes a considerable amount of time before the normal copying operation begins, for example, when performing automatic magnification selection that automatically selects the magnification that matches the copy paper after reading the original size. 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 as described above cannot detect the size of thick originals, stains appear on the periphery of copies, and problems with regular 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 that will be described in detail later. The object of the present invention is to provide 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 scanning optical system on 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 including a light-emitting element and a lens, and a light-receiving element and a lens for receiving reflected light reflected from the original on the document glass surface, and an openable/closable document size detector that covers the document glass surface. a document table cover; a first switch that detects an open state of the document table cover by opening and closing the document table cover;
A second switch for detecting a completely closed state is provided,
A portion where the signals of the plurality of detectors when the first switch is activated are compared with the corresponding signals of the detector when the second switch is activated, and the signals are inverted between them. The size of the original is detected on the assumption that there is no original.

Effect of the Invention With the above-described configuration, the present invention can accurately and quickly determine the size of a document placed on the glass surface of the document table without using a human DF, coloring the document table cover, or pre-scanning the optical system. Able to read and judge.

EXAMPLES Hereinafter, examples of the present invention will be described 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 at 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 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 a half-speed unit 13 consisting of two mirrors 11 and 12 that move at 1/2 the speed of the constant-speed unit 10, and a lens 14.
, and 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 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 half-speed unit 13.

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 table glass 2. The light-receiving element 19 is provided by a lens 2o so that the image of its light-receiving surface is formed at a focal point 21 where the previous image of its 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 1.
As a result of the image being formed on the light receiving surface of 9, an output signal is output from the light receiving element 19. Light emitting element 17. The light-receiving elements 19 are arranged so that they are focused on the document surface by the lenses 1, 8, and 20, respectively, so that the output from the light-receiving elements 19 is large.

Since characters and pictures are written in black on the document surface, if the field 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 set to 51 m to 10 m in diameter, and the focal length of the lens and the positional relationship between the lens, the light emitting surface, the light receiving surface, and the document platen glass 2 are adjusted so that the diameter is 51 m to 10 m. By setting it, you can get the best effect.

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 has a surface formed by the optical axes of the light emitting element and the light receiving element so that the light emitted from the light emitting element 17 is not reflected on the lower surface of the document table glass 2 and entering the light receiving element 19 as it is. 3.
As shown in the figure, it is installed at an angle of 20 degrees.

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 becomes lower, but the output becomes different depending on whether or not there is a document on the top surface of the platen glass 2. If there is Ov, an output of about 8V will be output. Tilt further to 30
If you tilt it more than a degree, it will gradually go down from 8V if there is no original or 8V if there is. As a result, in the embodiment of the present invention, the optimum angle of inclination is 20 degrees.

As explained above, the document size detector 16 is attached to the surface of the document glass 2 so as to be bent over the surface of the document glass 2.
Light emitting elements 17 are located at positions 23, 24, 25 and 26 shown in the figure.
Four of them are arranged so that the focal position of the light-receiving element 19 is the same, and 3. Mu4,84. A distinction is made between BS, Mu4, and B6 when placed horizontally.

To simplify the explanation, the numbers of the document size detectors that are in focus in Figure 4 are 23, 24, 25, and 25.
Call it 25.26.

In FIG. 5, the detectors that produce an output signal are marked O, and the detectors that do not produce an output signal are marked X, corresponding to each document size.

With this combination of O and X marks, 3. M4. B4. B5 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 SD 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 platen glass 2, the copying machine main body 1 assumes that there is no original document. Next 8
4, the document size detectors 23, 26 . '2
6 is activated, and an output of 8V is actually output from each document size detector. In contrast, the document size detector 24
The output of is OV. In the embodiment of the present invention, 4V is set as the paper detection threshold level, so the detection signal is O for the document size detectors 23, 25, and 26, as shown in the second row of FIG. , 24 becomes x, and the paper size can be detected.

In the case of a document with fine text written on ordinary white paper, the document size can be detected correctly with this method, but if there is a black photograph, etc. in the position that is exactly opposite to the document size detector 26, the document size The output of the detector 26 may be, for example, 2V, and the output may be x, resulting in detection of 86 size. In order to solve this problem, in this embodiment, switch 2
9 and 30 are provided, and when the document table cover 3 is closed from the glass surface to 300, 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 document with a black photo in the area of the document size detector 26, as shown in FIG. 7, when the switch 30 first operates, the combination becomes ○×○×, and then the switch 29 operates. Sometimes the original size detector 24, which until now would have failed because there was no original, is replaced by the original platen cover 3.
The white sheet 28 is detected and the value changes to 0. Other than that, nothing changes because I am reading the manuscript.

Here, we compare the output signals of the document size detector with switch 3o and switch 29 activated, and find that the areas where the mark changes from x to ○ are originally the areas where there was no original and the outside was being viewed through the glass surface. Recognize.

Therefore, even if this document is mistakenly detected as B5 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 copying paper is kept constant, the magnification is automatically changed and the magnification changing mechanism of the copying machine optical system is set 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 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 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 is pressed. The paper size 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 only detector 3 is activated and the remaining detectors (23) are activated is to wait until the document is placed or not, and after the document size detector 23 is activated, the remaining detectors (23) also begin to function. Leaving the light-emitting element of the device in constant operation consumes extra power, and the user may leave the device unattended with the document table cover 3 open. Generally, a light-emitting element with a lifespan of about 6 years, which is the lifespan of a copying machine, is very expensive, so a long-life element corresponding to this element is used only for the document size detector 23, and the remaining document size detectors In order to reduce the cost of copying machines, we are using light-emitting elements with a shorter lifespan.

Effects of the Invention As described in detail above, according to the present invention, the document size is first detected using a plurality of detectors with the document table cover open, and then the size of the document is detected by closing the document table cover. , which is characterized by improving the accuracy of size detection.

According to the present invention, it is possible to detect the document size with a very simple operation, and even though the document size is detected by the reflection of light on the document surface, even if there is a black part on the document, The detection accuracy is extremely high, with no false detections.

[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 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°3o.
····switch.

Claims (1)

[Claims] It is installed below the optical system that scans the original glass on the lower surface of the original glass of the copying machine body, and receives light reflected from the light emitting element and lens that radiates light toward the original glass and the original on the original glass. a plurality of document size detectors each comprising a light-emitting element and a lens for detecting the document size; a document cover that can be opened and closed to cover the document table glass; a first switch that operates when the document table cover is open; a second switch that detects a state, and detects signals from the plurality of document size detectors when the first switch is activated;
The size of the original is detected by comparing the corresponding signals of the plurality of original size detectors when the switch is activated, and assuming that there is no original in the area where the signal is reversed. A copier original size detection device characterized by the following.