KR850002616Y1 - Exposure lamp control circuit of electronic duplicator - Google Patents

Abstract

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Description

Exposure Lamp Control Circuit of Electrophotographic Copier

1 is a configuration diagram of an exposure lamp driving circuit of the present invention.

2 is an output waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: exposure lamp 2: triac

3: triac driving circuit 4, 9: rectifying circuit

5, 10: comparator 6, 11: single pulse generator

8: 90 degrees or more 7, 12: endgate

13: Oagate

The present invention relates to an exposure lamp control circuit of an electrophotographic copier, and in particular, when the drive signal of the exposure lamp is input by preheating the exposure lamp from the time when the drive signal of the main motor is input, the exposure lamp returns to normal brightness within a short time. An exposure lamp control circuit of an electrophotographic copying machine that enables exposure.

An electrophotographic copying machine injects a constant charge into a photoconductive layer such as ceranium, and forms a charge corresponding to the original by using an optical system in the surface photoconductive layer. The white portion of the original discharges the charge of the photoconductive layer, In the portion leaving the charge intact, the discharge of the charge on the white portion is proportional to the intensity of the exposure of the exposure lamp. Therefore, in order to perform high-performance radiation, the exposure amount of the exposure lamp must be sufficiently stable before the optical system moves.

For this purpose, the exposure lamp is conventionally started after the exposure lamp is turned on, and the exposure amount has been waited for sufficient time to stabilize. There was no flaw. In addition, in order to eliminate the time it takes for the exposure lamp to stabilize as described above, the exposure lamp is constantly turned on, but this is caused by heating the exposure lamp support and its peripheral devices due to the heat continuously emitted from the exposure lamp when the exposure lamp is turned on.

The present invention has been devised to solve the above-mentioned shortcomings. When the driving signal of the main motor is input and the motor is driven, the exposure lamp is lightly turned on and preheated, and then the exposure signal is input when the driving signal of the exposure lamp is input. The lamp is normally turned on to shorten the stabilization time of the exposure lamp.

In order to explain the present invention, the procedure of copying of an electrophotographic copying machine will be described.

If the temperature of the fixing unit in the copier is sufficiently high and there is no abnormality inside, the copier is ready for copying. In such a state, when the copy start key is pressed from the outside, the main motor of the copier and the drum of the copier first rotate about one revolution, and after inspecting the drum and each process, if there is no problem, the optical system moves to start exposure. If the exposure lamp is lightly turned on when the main motor is idling, the exposure lamp is preheated at that time, so the brightness becomes normal within a short time at the start of exposure.

This invention is described in detail by the accompanying drawings as follows.

FIG. 1 is an overall system diagram showing an embodiment of the present invention, and as shown therein, a triac 2 having a primary side connected to an AC power source AC through an exposure lamp 1 is connected to a triac driving circuit 3. In the electrophotographic copying machine controlled by the controller, the AND gate (7) in which a main motor driving signal (i) is input to one input terminal of a secondary side of a transformer (T) having a primary side connected to the AC power source (AC). The rectifier circuit (4), the comparator (5), and the monostable pulse generator (6) are connected to the other input terminal of the output terminal, and the exposure lamp driving signal (j) is connected to the input terminal of the secondary side of the transformer (T). It is connected to the other input terminal of the end gate 12 which is made to be input through 90 degree | times or more, the rectifier circuit 9, the comparator 10, the monostable pulse generator 11, and the AND gate 7, After connecting the output terminal of (12) to the input terminal of the oragate 13, the output terminal of the triac driving circuit (3) Air that is configured to connect to the input terminal, in this way will be described in detail the operational effect of the present design is configured as follows.

When AC power is applied, the AC waveform is output to the rectifier circuit 4 on the secondary side of the transformer T as shown in FIG. 2 (a). As shown, a rectified waveform is output, and this rectified waveform is compared with the reference voltage (h) in the comparator 5 only when the voltage is lower than the reference voltage (h), as shown in FIG. The signal is output. In this way, since the square wave output from the comparator 5 is applied to the monostable pulse generator 6, the pulse signal is generated as shown in FIG. 2 (g) at the time when the square wave is applied, and the other input of the AND gate 7 is input. Is applied to the terminal.

In addition, the AC waveform output from the secondary side of the transformer T is output by shifting the phase by 90 degrees as shown in the second (b) degree from the ninety degree or more phase 8 (8). Since the output signal of is applied to the rectifier circuit 9, the rectified waveform is outputted to the output side thereof as shown in the second (d), which is compared with the reference voltage h in the comparator 10 and Only when the voltage h is lower, a high potential signal is output as shown in FIG. 2 (f). In this way, since the square wave output from the comparator 10 is applied to the monostable pulse generator 11, when the square wave is applied

In such a state, when the main motor driving signal i, which is a high potential signal, is applied to one input terminal of the AND gate 7 by pressing the copy operation key, the pulse signal output from the monostable pulse generator as described above is an AND gate. (7) and the oak gate 13 are applied to the control input terminal of the triac driving circuit 3, so that a pulse signal is output to the output side thereof, and is applied to the gate of the triac 2, whereby the triac 2 ) Is conducted when the pulse signal is output from the triac driving circuit 3 as shown by the solid line in FIG. 2 (i), and the phase of the AC power source AC is reversed.

Thus, while the main motor driving signal (i) is applied and the main motor is idling, the triac 2 conducts for only a short time to turn on the exposure lamp 1, so that the holder of the exposure lamp and its peripherals are not heated. Only the exposure lamp 1 is preheated.

In this way, when the exposure lamp driving signal j is applied to one input terminal of the AND gate 12 while the exposure lamp 1 is preheated, the pulse signal output from the monostable pulse generator 11 as described above (the Since 2 (h) is applied to the triac driving circuit 3 through the end gate 12 and the oragate 13, a pulse signal is output to the output side thereof and is applied to the gate of the triac 2, and thus the triac The evil (2) is turned on when the pulse signal is output from the triac driving circuit (3) as shown by the solid line in FIG. 2 (j), and at the time when the phase of the AC power source AC is reversed.

As described above, the present invention illuminates and exposes the exposure lamp only for a short time while the main motor is idling, so that normal exposure can be performed immediately after the exposure lamp driving signal is applied, and during the preheating of the exposure lamp. Since the exposure lamp is turned on only for a short time, the exposure lamp holder and its peripheral devices are not heated, so that the performance of the optical system can be maintained at an optimal state.

Claims (1)

(Correct) In an electrophotographic copying machine which controls a triac 2 connected to both ends of an alternating current power source via an exposure lamp 1 with a triac driving circuit 3, a transformer T having a primary side connected to the alternating current power source. The rectifier circuit (4), the comparator (5), and the monostable pulse generator (6) are connected to the other input terminal of the AND gate (7) in which the secondary side of the main circuit driving signal (i) is input to one input terminal of And a rectifier circuit 9 or more than 90 degrees to the other input terminal of the end gate 12 through which the exposure lamp driving signal j is input to the secondary input terminal of the transformer T on one side input terminal. ) And the output terminals of the end gates 7 and 12 are connected to each other through the comparator 10 and the monostable pulse generator 11 and the ora gate 13 controls the triac driving circuit 3. An exposure lamp control circuit for an electrophotographic copy machine, characterized in that it is connected to an input terminal.