JPH073554B2 - 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 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. Alternatively, the original plate cover that holds the original document may be colored in light yellow or blue over the entire surface, or a stripe may be attached, and the original document may be scanned before exposure scanning by the optical system. There is a method of reading an original with an optical sensor attached to the 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-mentioned problems, the present invention is provided below an optical system for scanning the platen from the lower surface of the platen glass of the copying machine body, and irradiates the platen glass with light. A plurality of document size detectors each including a light emitting element and a lens, and a light receiving element and a lens that receives reflected light from a document on the platen glass surface, and an openable and closable platen cover that covers the platen glass. A switch for detecting the open state of the platen cover is provided, and signals of a plurality of document size detectors when the platen cover is opened and a plurality of document size detectors when the platen cover is closed are provided. Signal of
Even if it is detected that there is no document because the relevant part of the document is black when the platen cover is open, it is considered that there is a document if the signal does not reverse with the platen cover closed, The size of the document is detected by assuming that there is no document in the portion where the signal is inverted.

Operation The present invention has the above-mentioned configuration without using the ADF.
Further, it is possible to accurately and quickly read and determine the size of the original placed on the glass surface of the original plate without coloring the original plate cover or preliminarily scanning the optical system.

Also, if the original size is detected using a reflective original size detector and the black portion of the original is read and it must be detected that there is an original, it is falsely detected that there is no original. Even in this case, the error can be corrected by comparing the signals of the document size detector when the platen cover is closed, and the size detection accuracy is improved.

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 is composed of 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 optical image of the original 4 is 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. Constant velocity unit
A plurality of document size detectors 16 are provided at positions in a direction that does not hinder the movement of the document 4 when the 10 and the half-speed 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 the light emitting surface of the light emitting element 17 is imaged on the upper surface 21 of the platen glass 2. The light receiving element 19 is provided by a lens 20 so that an image of its light receiving surface is formed at a focal position 21 where an image of the previous light emitting surface is formed. Since the light from the light emitting element 17 is imaged on the part where the document 4 is on the platen glass 2, it is bright and the bright part is imaged on the light receiving surface of the light receiving element 19. An output signal is output from. Light emitting element 1
7. The light receiving element 19 is arranged so that the surface of the original is focused by the lenses 18 and 20, respectively.
The output from 19 is large.

Since the characters and pictures are written in black on the document surface, the focus position
If the 21 focused screen is made 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 this light emitting element is 5 mm to 10 mm in diameter, and
Optimum results are obtained by setting the focal length of the lens, the positional relationship between the lens and the light emitting surface and light receiving surface, and the platen glass 2 so as to form a circle of mm.

Since the light from the light emitting element 17 passes through the 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 has a surface formed by the light emitting element and the optical axis of the light receiving element so that the light emitted from the light emitting element 17 does not reflect on the lower surface of the original platen glass 2 and directly enter the light receiving element 19. As shown in FIG. 3, the platen 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 whether or not there is a document on the upper surface of the platen glass 2. If there is no document when tilted by 10 degrees or more. 8V if there is 0V
The output of the degree comes out. If you tilt it further and tilt it more than 30 degrees, it will gradually drop from 8V when there is 0V when 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 original size detector 16 is the original glass 2
The light emitting element 17 and the light receiving element 1 are attached at 23, 24, 25 and 26 shown in FIG.
Four of them are arranged so that the focal position of 9 comes, and the horizontal placement of A3, A4, B4, B5 and A4 and B5 used in Japan is distinguished.

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 are indicated by a circle, and detectors that do not output are indicated by a cross, corresponding to each document size.

This combination of O and X 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 includes a switch 29 that operates when the original platen cover 3 is completely closed, and a switch 30 that is pressed by one end of the hinge 27 when the original platen cover 3 is opened 30 ° from the original platen glass surface. There is.

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 document. Next, when B4 paper is placed, the document size detectors 23, 25, and 26 are activated, and in fact, the document size detector outputs 8V. On the other hand, the output of the document size detector 24 is 0V. In the embodiment of the present invention, 4V is set as the threshold level for paper detection, so that the detection signal is ◯ for the document size detectors 23, 25, 26 as shown in the second row of FIG.
And, 24 becomes x, and 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 may be, for example, 2V, and the output may be x, and the B5 size may be detected.
In order to solve this, in this embodiment, the switch 29 and
30 is provided, and first, when the document table cover 3 is closed 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 original size detector 24, which used to be X because there are no originals until now, detects the white sheet 28 of the original platen 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 switch 30 and switch 29 in operation are compared, and the place where X changes to ○ is that there was originally no document and the outside was seen through the glass surface. Recognize. Therefore, even if this document is erroneously detected as B5 size when the platen 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 zooming mechanism of the optical system of the copying machine is set so that the entire surface of the original document fits on the entire copy paper.

The operation of selecting the paper size or the magnification is started when the document 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 29
Does not close, so it cannot enter operations such as paper size selection or magnification selection. In the embodiment of the present invention,
When the copy start switch of the copying machine body 1 is pressed without closing the switch 29, the paper size is judged by the signal output from the document size detector 12 at the time of pressing the switch.
The operation of selecting the paper size or the magnification is started.

Even if the Coby 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 scanner always operating consumes extra power for this purpose, and the user may leave the equipment with the platen cover 3 open. Therefore, the element with a life of about 5 years, which is the life of the copying machine, is very expensive, so the long-life element corresponding to this is used only for the original size detector 23, and the remaining original size detector is The cost of the copying machine is reduced by using a light-emitting element having a short life.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the size of a document is detected by first detecting the document size with a plurality of detectors in a state where the document cover is opened, and then the document cover is closed. The feature is that the detection accuracy is improved.

According to the present invention, it is possible to detect a document size with a very simple operation. Even if the document size is detected by the reflection of light on the document surface, it is assumed that the document has a black portion. Even if it is not detected, the detection accuracy is very high.

BRIEF DESCRIPTION OF THE 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. Fig. 5 is a layout of the scanner, Fig. 5 is a correspondence diagram of output signals corresponding to each document size of the detector, Fig. 6 is a side view showing the opening and closing of the platen cover, and Fig. 7 is a size when the platen cover is opened and closed. It is an explanatory view of an output signal when detecting accuracy is raised. 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. A light-emitting element and a lens, which are provided below an optical system for scanning the platen from the lower side of the platen glass of the main body of the copying machine, and emit light toward the platen glass, and an original on the platen glass surface. A plurality of document size detectors each comprising a light receiving element and a lens for receiving the reflected light, a document table cover that can be opened and closed to cover the document table glass, and a switch that detects the open state of the document table cover are provided. , Compare the signals of multiple original size detectors with the platen cover open and the signals of multiple original size detectors with the original cover closed, and then open the original cover Even if it is detected that there is no document because the relevant part of the document is black, it is considered that there is a document if the signal does not reverse with the platen cover closed, and the signal is reversed. In Copier document size detection apparatus as draft is considered without, characterized in that it was to detect the size of the document.