JPS5855942A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain a copying machine of high safety at a low cost by starting the operation of a process means such as a corona charger and the like only after the rotation of a rotating body is confirmed. CONSTITUTION:A series of pulses DP complying with the revolutions of a photosensitive drum are generated with a light emitting diode 54 and a photodetector 55 provided to face the holes 52 of a disc 51 which rotates coaxially with the drum. When a power switch is turned on, a microcomputer M starts program processing, and decides the inputting of a copying button signal CPB through an input port I1. A main motor is turned on. The microcomputer decides whether the pulse state signal PS of a circuit A, which is 0 when the pulses DP are inputted repeatedly and is otherwise 1, is 1 or 0 through an input port I2. When said signal is 1 despite N times of the decision, the microcomputer displays the abnormality of the drum by outputting a DISP, and shuts off electric power sources V10, V24. On the other hand, when the output of the circuit A is 0, the microcomputer outputs HVT1, HVT2 and AEX to operate chargers and lamps. Thus the cost is reduced and the safety is improved.

Description

[Detailed description of the invention] The present invention relates to an image forming apparatus K such as a transfer type copying machine.

Conventionally, among copying machines that perform corner charging, exposure, development, corona transfer, and afterimage removal while rotating a photoreceptor, there is one that turns on a four-way charger and a static eliminator at the same time the photoreceptor starts rotating. .

In this case, if the photoreceptor does not rotate for some reason despite the copy start command, the high voltage generated by the Fusina charger operated in accordance with the command may cause local charging unevenness on the photoreceptor that is difficult to remove.

In some cases, the photoreceptor may be deteriorated.

In order to eliminate the above-mentioned drawbacks, the present invention starts the operation of a process means such as a corona diaphragm only after the rotation of the rotating body is confirmed, and the rotation confirmation is usually performed for timing control of the process. This is done using signals.

The present invention will be explained below with reference to FIG. 1 of an example of a copying machine.

This is an electrophotographic copying machine using a powder development transfer method, and 1 places the original 08 to be copied on a transparent document placing table with the leading edge of the document 08 aligned with the standard position of the document placing table, and holds it with the document cover 2. . Below the document table 1, a document illumination lamp 6, movable counters 4 and 5, a fixed set of lenses 6 and 7, and a photosensitive drum 8 are arranged as indicated by solid lines in the figure. Further, a fan 50 is disposed around the entire document mounting table heated by the document illumination lamp.

When the unillustrated hubby key is pressed, the photosensitive drum 8 starts rotating in the clockwise direction shown in the figure, and each charger and each lamp, which will be described later, starts operating, and at the same time, the movable parts of the optical system, such as the manuscript illumination lamp 6, the movable cellar 4, 5 moves to the position indicated by the broken line in the figure. When the photosensitive drum 8 completes a predetermined rotation, a signal to start exposure is issued, and the document illumination balance 6 and the first electric tip 4 move rightward from the position shown by the broken line at the same speed as the circumferential speed of the photosensitive drum 8. , 21st to 5 starts to move rightward from the position shown by the broken line at half the speed, but is illuminated from below by the document illumination lamp 6, and the image of 9i@On is moved from the movable mirror 4, 5. Inseller lens 6. An image is formed on the photosensitive drum 8 at the exposure section 9 by an optical system consisting of an S2 7 and the like. When the exposure is completed according to the signal according to the size, the original s
Turn off WA light lamp 6, turn off lamp 3, moveable cellar 4.5
stops moving to the right in the figure and immediately returns to the opposite direction, that is, to the left in the figure. The above operation is repeated according to the number of copies specified in advance by a key (not shown). When the exposure for the specified number of sheets is completed, it returns to the original illumination fan position and stops. Note that the speed of movement to the left in the drawing increases the copying efficiency faster than the speed of movement to the right in the drawing. here 51
is a blanking lamp that is lit when the lamp 3 is off and off when it is on, and minimizes toner retention during non-exposure.

The photosensitive drum 8 has a transparent insulating layer formed on a photosensitive layer, and rotates clockwise in the drawing as described above. The photosensitive drum 8 is first supplied with an AC high-voltage current from a high-voltage power source (not shown), and is then subjected to AC charge removal by an AC static eliminator 10 and simultaneously exposed to light from a lamp 11 to erase charges on the surface of the insulating layer and inside the photosensitive layer. , followed by a primary charger 12 to which the high voltage current (A) is supplied from a high voltage power source (not shown).
It is charged to (10) by (10). Then, when it reaches the exposure part 9,
The image from the illumination unit 16 is illuminated by a sliver), and at the same time, an AC static eliminator 14 is supplied with an AC high voltage current from a high voltage power source (not shown).
The AC static electricity is removed by And then rung 15
All over J! The light forms an electrostatic latent image on the surface of the photosensitive drum, which enters the developing device 16. The developing device 16 consists of a container 17 containing developer, a developing p-roller 18, and a doctor blade 19. The latent image is converted into a JII image.

Next, the I-light transfer paper P is fed from the paper feed section and placed on the photosensitive drum 8.
The image on the photosensitive drum 8 is transferred onto the transfer paper P by being charged by the (+) high-voltage electricity tIL from the high-voltage power supply by the transfer charger 20. After the transfer is completed, the static electricity is removed by the separation static eliminator 21 to which AC high-voltage current is supplied from the high-voltage power source, and the adhesion force with the photosensitive drum 8 is weakened. The transfer paper Pa22 is sucked by the roller 2511C, separated from the photosensitive drum 8, and guided to the fixing section 26 by the belt 24 and guide 25. The remaining developer on the photosensitive drum 8 is wiped off by the edge s27 of the blade cleaner 27 pressed against it, and the next cycle is repeated again.

After repeating the cycle for a predetermined number of sheets, the rotation is continued, and the internal charge of the photosensitive layer is removed by the above-mentioned static elimination using the AC static eliminator 14 and full rain exposure using the lamp 15, in order to prepare for the next time. It stops after the lid has rotated a specified amount.

FIG. 2 is a cross-section of a disk 51 that rotates coaxially with the photosensitive drum for detecting the rotational state of the photosensitive drum.

It is a plan view and has a hole 52. 53#'i is a photo-in rack with a light emitting diode 54, a receiver jt, and an element 55 provided opposite to the number 6, and a series of pulses DP are generated from the receiver Jjt and the element 55 in accordance with the rotation of the drum.

Figure 6 shows a circuit for determining the rotating state of the drum and controlling the sequence of each process. The program memory 11 (which has an OM) shown in the flowchart performs the above judgment and control.When the pulse DP is repeatedly input, the output is 0. Otherwise, the output is 1.The CPB is a circuit that outputs 1 using a copy button (not shown). The signals, Vse and Vza are drive power supplies, Ml is a drive signal for the main motor that rotates the drum, HVTI is a signal for applying high voltage to the front primary charger 10.12 and the transfer charger 20, and HVTx is a binary charger. a signal for applying high voltage to the charger 14 and the separation charger 21;
AKX is front rung 11. IKX is a signal to turn on the front rung 15, IKX is a signal to start scanning, a signal to start feeding paper from the PFd cassette, and a rounded signal to display a DISP Hiro error warning. The input and output are connected to.

In FIG. 4, when a power switch (not shown) is turned on, the microcomputer M starts Gudaram processing and turns on the motor (step 2). Next, it is determined via the input port 8 whether the input of the pulse state signal PS is 1 or 0 (step 6).

Even if the determination routine is repeated N times (step 4), if the result is 1, that is, no pulse is generated, DISP is output to indicate an abnormality in the drum, and the power to vl and Vxa is cut off (step 5). . Routine time for N times
v is longer than the cycle of P, and corresponds to a time that is several times to ten times as long. In addition, more than 60 pulses are output for every five rotations of the drum. If a predetermined number of pulses DP are input to circuit A before the routine is completed N times, the output of circuit A becomes O, and the microcomputer determines this and outputs HV'I°5.

Output HVTx and AEX, and operate the charger and rung (step 6). In other words, it is safe to perform charging etc. only after confirming that the drum is normal.

Input the next pulse DP and start counting 1 island through I3, and start image exposure until the end of f%.
Expect. During this time, the drum is cleaned and preparations are made for sensitivity correction, potential stabilization, etc. When %1 is counted, IEX, F, and AD are output, and the latent image forming process begins (step 8). Further, when the pulse CLK is counted by nx, PF is output and paper is fed. When the transfer is completed, it is determined whether the predetermined copying is completed or not, and the latent image formation is repeated. When copying is complete, first turn off HVT1, then turn off HVTz a little later.
Turn off.

1 Next, count the pulse CLK 3 times a day, turn off Ml and AEX, stop the entire sequence, and wait. When the copy button is turned on again, a similar routine begins again.

As mentioned above, since the sequence is started only after confirming the rotation of the drum in case of a misfire ψ, it is possible to provide a copying machine with a high degree of safety at low cost.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copying machine to which the present invention can be applied, FIG. 2 is a plan view of a means for detecting the state of a rotating body in the present invention, FIG. 3 is an example of a control circuit in the present invention, and FIG. The figure is a control 70-chart diagram of FIG. 6, and 8 in the figure is a drum,
51 Koku disk, 14.20 is Corona Teidenki〇

Claims (1)

[Claims] a rotating body, and a plurality of process means for image formation, transfer, and afterimage removal, including means for charging or neutralizing the rotating body;
and a pulse generating means for controlling the timing of at least one of the process means, and the charging or discharging means starts operating only after confirming that the rotating body is not in an abnormal state after an image formation start command is issued. An image forming apparatus characterized in that the image forming apparatus is configured to determine the confirmation using an upper d-pipulse.