JPH01209461A - Start position detector for optical scanning body of copying machine - Google Patents

Abstract

PURPOSE:To abolish a dedicated optical scanning body start point detection switch and to simplify the mechanism and circuit by using an exposure sensor which detects the light and shade of a document and providing the exposure sensor with a start position detecting function for an optical scanning body. CONSTITUTION:The exposure sensor 21 is provided which detects the light and shade of the document 19 so as to adjust the quantity of light of a copy lamp 20 automatically. Then a copying machine main body 2 is provided with a detection plate 22 which reflects light on the exposure sensor 21 at the start position A of the optical scanning body 18 and the exposure sensor 21 is provided with the start position detecting function for the optical scanning body 18. Consequently, the dedicated optical scanning body start position detection switch is abolished and the mechanism and circuit are simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a device for detecting the starting position of an optical scanning body movably guided to a copying machine body, and is used in, for example, an electrostatic transfer copying machine. Ru.

<Prior Art> Generally, in a copying machine that performs exposure by moving a copy lamp, the movement timing and starting position (home position) of an optical scanning body such as a mirror base unit are important factors in copying. Therefore, conventionally, a dedicated detection switch was provided to detect the starting position of the optical scanning body, and the starting position was detected by turning on this switch when the optical scanning body returned to the home position.

Problems to be Solved by the Invention However, the conventional technology requires a dedicated detection switch and its accompanying circuit, which makes the mechanism and circuit complicated and increases the cost.

In view of the above, it is an object of the present invention to provide an optical scanning body starting point position detection device that has a simplified mechanism and circuit.

Means for Solving the Problems> The means for solving the problems according to the present invention is as shown in FIG.
, a copy lamp 20 that irradiates light onto the original 19 placed on the original table 1 of the copy Isomoto book 2; and the copy lamp 20.
In a copying machine equipped with an exposure sensor 21 that detects the density of the original 19 in order to automatically adjust the light amount of the original 19, the copying machine body 2 includes a detection device that reflects light onto the exposure sensor 21 at the starting position A of the optical scanning body 18. A plate 22 is provided, and the exposure sensor 21 has a function of detecting the starting position of the optical scanning body 18.

In the above-mentioned problem solving means, the exposure sensor 21 that detects the density of the original 19 is used, and the exposure sensor 21 has a function of detecting the starting position of the optical scanning body 18, so that a dedicated optical scanning body can be used. The starting position detection switch can be eliminated, and the mechanism and circuit can be simplified.

<Example> Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the optical scanning body starting position detection device of the present invention, FIG. 2 is a starting point position detection circuit diagram, FIG. 3 is an output waveform diagram of the exposure sensor, and FIG. 4 is an overall configuration diagram of a copying machine.

First, to explain the overall configuration of the copying machine shown in FIG. 4 is a photoreceptor whose surface is uniformly charged by a charger 5 and on which an image is projected by the optical means 3;
6 is a developing device that visualizes the electrostatic latent image formed on the surface of the photoreceptor 4; 7 is a developing device that exposes the paper that is selectively fed from the paper feed section 8 and sent through the registration rollers 9; A transfer charger 10 transfers the developed image on the photoreceptor 4; a cleaning device 11 removes the developer of the developed image remaining on the photoreceptor 4;
is a static eliminating means that uniformly eliminates the potential on the surface of the photoreceptor 4. Note that after the transfer, the paper is peeled off from the photoreceptor 4 and conveyed to the fixing section 12, where the transferred image is fixed.

Further, in the figure, 14 is a paper discharge tray, 15 is a composite double-sided copying device, 16 is an intermediate tray thereof, and 17 is an automatic feeding device.

In the copying machine of the present invention, the optical scanning body 18 is movably guided to the copying machine main body 2, and the document table 1 of the copying machine main body 2 is provided.
A copy lamp 2 that irradiates light onto a document 19 placed above.
0, and an exposure sensor 21 that detects the darkness of the original 19 in order to automatically adjust the light intensity of the copy lamp 2°,
The copying machine main body 2 is provided with a detection plate 22 that reflects light to a starting point position A″C exposure sensor 21 of the optical scanning body 18,
The exposure sensor 21 has a function of detecting the starting position of the optical scanning body 18.

The optical scanning body 18 consists of a copy lamp unit 24 and a mirror base unit 25, as shown in FIG. The copy lamp unit 24 includes a reflecting mirror 24b having a C-shaped cross section attached to a unit body 24a, and a reflecting mirror 24b.
The copy lamp 20 is fixed inside the copy lamp 20. Further, the mirror base z knit 25 includes a base unit main body 25a fixed to the lower surface of the main body 24a of the copy lamp unit 24, a mirror 27 attached to the main body 25a, and the unit main body 25a. The exposure sensor 21 is disposed inside the sensor case 28 at the bottom of the exposure sensor 21. Above the exposure sensor 21, light is incident on the exposure sensor 21 through a copy lamp unit 24 and a mirror base unit 25, respectively. Through holes 29 and 30 are formed for the purpose of the optical scanning body 18.As shown in FIG. 1, the optical scanning body 18 is movable in the X direction by a drive motor and a drive wire (both not shown).

Further, the starting point A of the optical scanning body 18 is as shown in FIG.
The detection plate 22 is set at a position in front of the leading edge 19a of the original 19 in the original transport direction Y, and is attached to the back surface of the opaque copying machine main body 2 adjacent to the transparent original table 1. Detection plate 2
2 is color-coded in the document conveyance direction Y from the starting point A, with the front part being white and the rear part being black. The configuration is such that the color components are reflected at the boundary Z and enter the exposure sensor 21 directly below it.

The exposure sensor 21 is a photosensor, and is connected to a first amplifier 32 and a second amplifier 33 as shown in FIG. The positive input terminal of the comparator 34 is connected to the midpoint of resistors R1 and R2, and the output terminal of the comparator 34 is connected to a control circuit (CPU) 35, and the output signal (H or L) of the comparator 34 is used to control the optical scanning body 18.
The controller is configured to detect that the controller returns to the starting position A.

In the above configuration, when the optical scanning body 18 is driven in the X direction in FIG. 1, the exposure sensor 21 reads the density of the document, and the automatic exposure function automatically adjusts the light amount of the copy lamp 20. Further, the mirror base unit 25 serving as the optical scanning body 18 returns to the starting position A again after scanning the original. Therefore, if a detection plate 22 having white and black areas is provided at a position in front of the leading edge of the document in the document transport direction Y, the mirror base unit 25 of the optical scanning body 18
When the light returns to the starting point A, the exposure sensor 21 reads the difference in output between white and black, and based on this output difference, an H or L signal is output from the comparator of the detection circuit, allowing the starting point A to be detected. . Exposure sensor 2 at this time
Figure 3 shows the output changes of 1. The output is amplified by first and second amplifiers 32 and 33 as shown in FIG.
It is compared with the voltage W by a comparator 34 and outputs a starting point position signal P. By having the control circuit 35 determine this, the mirror base unit 25 of the optical scanning body 18
It is detected that has returned to the starting position A (home position).

In this way, when the starting point position detection function by the exposure sensor 21 is used, there is no need for a dedicated starting point position detection switch unlike in the past, the mechanism and circuit can be simplified, and the cost can be reduced.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, the detection plate 22 is not limited to being color-coded into two colors, white and black, as in the above-mentioned embodiment, but the same color but with different tones can be used to achieve the same effect as described above.

Furthermore, the present invention is not limited to the method in which the copy lamp 20 is moved as in this embodiment, but can also be applied to a method in which the document table is moved. Furthermore, the position of the detection plate 22 is as in the above embodiment (,
It is sufficient to adopt a method in which the light enters not only directly above the exposure sensor 21 but also at the starting position A in relation to the copy lamp 20.

Further, the exposure sensor 21 may have not only a light receiving function as in the above embodiment but also a light emitting function.

<Effects of the Invention> As is clear from the above description, according to the present invention, an exposure sensor that detects the density of a document is used, and this exposure sensor has a function of detecting the starting position of the optical scanning body. This has the advantageous effect that the optical scanning body starting position detection switch can be eliminated, and the mechanism and circuit can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the optical scanning body starting position detection device of the present invention, FIG. 2 is a starting point position detection circuit diagram, FIG. 3 is an output waveform diagram of the exposure sensor, and FIG. 4 is the overall configuration of the copying machine. 1: Original table, 2: Copying machine main body, 18: Optical scanning body, 19
: Original, 20: Copy lamp, 21: Exposure sensor, 2
2: Detection plate, A: Starting position. Applicant Sharp Corporation

Claims (1)

[Claims] An optical scanning body movably guided to the copying machine body, a copy lamp that irradiates light onto the original placed on the document table of the copying machine body, and an optical scanner that irradiates light onto the original placed on the original platen of the copying machine main body, and an optical scanner that illuminates the original to automatically adjust the light intensity of the copy lamp In a copying machine equipped with an exposure sensor that detects density, a detection plate is provided on the copying machine body to reflect light to the exposure sensor at a starting position of the optical scanning body, and the exposure sensor detects the starting position of the optical scanning body. What is claimed is: 1. A device for detecting the starting point position of an optical scanning body of a copying machine, characterized in that the device has the following functions: