JPH051925B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a xerographic copying apparatus.

Conventional structure and its problems Conventionally, when copying a large original, you would place the part you want to copy on the original glass, make a copy at the maximum copy size, and then cut out the necessary part. Otherwise, it was necessary to make several trial copies to obtain a copy of the required size, resulting in unnecessary loss of time and waste of paper. In addition, the copy start switch that comes with the main unit,
In the case of large-format originals, this has the disadvantage that the starting operation is difficult to perform because it is located at the bottom of the original.

Purpose of the Invention The present invention aims to eliminate the drawbacks of the above-mentioned conventional example, and when copying a large original that is outside the specified size, it is possible to recognize the placement of the original and to make necessary copies. It is an object of the present invention to provide a dry copying device that can easily and accurately copy parts.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a copying apparatus in which an original image on an original placing glass is formed as a latent image on a photoreceptor through a mirror and a lens by reciprocating movement of an exposure lamp. The feature is that the scan speed of the exposure lamp and the exposure voltage are varied, and that only the optical system is controlled to operate.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a dry type copying apparatus. When a document is placed on a document placement glass 1 and a copy start switch (not shown) is turned on, a constant velocity unit consisting of an exposure lamp 2 and a first mirror 3, A half-speed unit consisting of mirrors 4 and 5 and moving at half the speed of the constant-speed unit scans the photoreceptor 10 through an optical path consisting of a through lens 6 and fixed mirrors 7, 8, and 9, exposing the original. A latent image corresponding to is formed on the photoreceptor 10. This latent image is then developed by a developing device 11, and a toner image is created on the photoreceptor 10. On the other hand, copy paper is fed from the cassette 12 and transferred to the transfer device 13.
The image on the photoreceptor 10 is transferred to copy paper, fixed by the fixing device 14, and stored in the paper discharge section 15.

In this embodiment, before carrying out such a copying process, the light amount of the exposure lamp 2 is controlled,
Furthermore, by scanning at a controlled speed with a constant velocity unit consisting of an exposure lamp and the first mirror, it is possible to correctly position the range of the document to be copied on the document placement glass 1 in the case of large documents. This is what I did.

FIG. 2 is a block diagram of a control circuit for an optical motor, and the explanation will be based on this. First, the speed sensor 17 built into the motor detects the rotation speed of the motor 16.
A speed signal is output from the amplifying circuit 18, and the amplifying circuit 18 amplifies this signal. That is, this speed signal changes depending on the rotation speed of the motor. On the other hand, an oscillator 19 such as a crystal oscillator
The signal from the CPU (Central Processing Unit) 22 is frequency-divided by the frequency divider 20 and input to the decoder 21 as a reference signal, and the reference signal selected by the signal from the CPU (Central Processing Unit) 22 is input to the phase comparison circuit 23. . The phase comparison circuit 23 compares the signal input from the speed sensor 17 with the above-mentioned reference signal, and when the motor speed is slow, the effective voltage of the motor is increased, and when it is fast, the speed is corrected in the direction of lowering the effective voltage. It is determined by the circuit 24, controls the ON time of the drive circuit 25, and rotates the optical motor at a constant speed.

Therefore, the reference signal can be changed by the select signal from the CPU 22, and the optical lamp can be scanned at a constant variable speed as required. In this embodiment, the light amount of the exposure lamp is further controlled so as to be variable depending on the thickness of the document.

FIG. 3 is a block diagram of a light amount control circuit for an exposure lamp. To explain this circuit, first, the voltage of the exposure lamp 26 is detected by an exposure voltage detection circuit 27, and this is used as an exposure amount control signal to be sent to a light amount stabilizing circuit 28. Enter. The level of this signal changes depending on the lamp voltage. On the other hand, the reference signal generated by the exposure amount control circuit 29 is input to the decoder 30, and based on the light amount switching signal from the CPU 31, a constant exposure amount control signal is also input from the decoder to the light amount stabilization circuit 28, and the two The output level is determined by two signals. That is, when the voltage of the exposure amount control signal obtained from the lamp voltage is increased, the output level decreases, and conversely, when the voltage of the exposure amount control signal obtained from the lamp voltage is decreased, the output level increases. This output level is input to the light amount determining circuit 32 to generate a trigger pulse, and if a triax, for example, of the drive circuit 33 is used, the gate of the triax is triggered to control the brightness of the exposure lamp. That is, an arbitrary exposure lamp voltage can be obtained depending on the level of the reference signal of the exposure amount control circuit 29, and therefore, the brightness of the exposure lamp can be controlled.

By making the scanning speed and exposure voltage of the exposure lamp variable in this way, by pressing a specific switch, the document surface will be scanned by the trading company at the preset brightness and scan speed. This makes it possible to easily determine which parts will be copied. Furthermore,
By programming on the CPU, after pressing a specific function switch, for example, using the numeric keypad switch, it is possible to set the desired brightness and scan speed. It is possible to fully adapt to the thickness of the base paper.

When determining the document placement position by visual observation using transmitted light from an exposure lamp, it is not preferable to operate an image forming process centered on an optical system and a photoreceptor because of fatigue of the photoreceptor and consumption of toner. Therefore, in this embodiment, the optical system, photoreceptor, and other drive systems are configured to be driven by separate motors. Therefore, only the optical system is controlled by operating the changeover switch.

In addition, in the case of large-sized originals, the original is usually placed on the copy start switch, making it difficult to press the copy start switch. In this case, by attaching a wired remote switch, it can be easily operated, and has the effect of reducing copy loss and making it very easy to set up the original.

If this wired remote switch is provided with a copy start switch, variable operation switches for scan speed, exposure voltage, etc., the operation will be easier.

Effects of the Invention As detailed above, according to the present invention, for example,
By pressing a specific switch, the document surface can be illuminated and scanned at the preset brightness and scan speed, making it easy to determine which parts will be copied. Furthermore, if you program on the CPU, after pressing a specific function switch, you can set the desired brightness and scan speed using the numeric keypad switch, for example, and set the desired scan speed. It is possible to fully adapt to the transparency and thickness of the base paper.

In addition, in the case of large-sized originals, the original is usually placed on the copy start switch, making it difficult to press the copy start switch. In this case, by attaching a wired remote switch, it can be easily operated, and has the effect of reducing copy loss and making it very easy to set up the original.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a dry copying apparatus, FIG. 2 is a block diagram of a control circuit for an optical motor according to the present invention,
FIG. 3 is a block diagram of a light amount control circuit for the exposure lamp. 1...Original placement glass, 2...Exposure lamp, 1
0...Photoreceptor.

Claims (1)

[Scope of Claims] 1. A copying device that forms a latent image on a photoreceptor through a mirror and a lens by reciprocating an exposure lamp by reciprocating an original image on a document placement glass, the scanning speed of the exposure lamp What is claimed is: 1. A dry type copying apparatus comprising means for controlling an exposure voltage to be varied and operating only an optical system. 2. Claim 1, characterized in that the control means controls the means for issuing the copy start signal by a wire connected to the main body of the copying apparatus.
Pyrophotographic copying device as described in Section 1.