JPS6310167A - Electrophotographic recorder - Google Patents

Abstract

PURPOSE:To contrive the increase of the safety and the reduction of a trouble by providing a circuit for detecting the abnormal state of a voltage or a current of a high voltage supplied from a high voltage power source circuit, and operating a control circuit. CONSTITUTION:The titled device is provided with an abnormal state detecting circuit 9a for an electrifying power source circuit 8a, an abnormal state detecting circuit 9b for a developing bias power source circuit 8b, an abnormal state detecting circuit 9c for a transfer power source circuit 8c, and an abnormal state detecting circuit 9d for a separation power source circuit 8d. In such state, when a high voltage supplied to each discharge wire or a developing sleeve 10 from a high voltage power source circuit 8 consisting of a high voltage power source 81 and a power source circuit 82 becomes the abnormal state, each of said circuits detects it, and sends an abnormal state informing signal 212 to a control circuit 21. By such abnormal state informing signal 212, the control circuit 21 displays the abnormal state on the display part, etc., of a console panel, and also, executes a control for setting the power source circuit to an off state, etc. In such way, the abnormal state of discharge of the high voltage power source circuit 8 can be detected in an early state, and an electrophotographic copying device which is safe and scarcely causes the trouble is obtained.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an electrophotographic recording apparatus, and more particularly to an electrophotographic recording apparatus equipped with abnormality detection means for a high-voltage WL source.

[Conventional technology]

In a conventional electrophotographic copying apparatus, for example, as shown in the internal structure of FIG. After an electrostatic latent image of the original W4D is formed by the optical system 3, a developing sleeve 10 in the developing unit 4 is applied with a developing bias voltage by the developing bias power supply circuit 8b.
Development is performed using the developer b. The toner image on the photosensitive drum 1 obtained by the development is transferred onto the recording paper P by the transfer device 5. 11 paper P on which the toner image was transferred
is separated from the photosensitive drum 1 by a separator 6, fixed by a fixing device by a conveying means (not shown), and discharged from the apparatus. After the toner image has been transferred, the photosensitive drum 1 is cleaned by a cleaning device 7 and is ready for the next image formation. Each of the discharge wires 10a, 10c, 10d and the developing sleeve 10b of the charging device 2, developing device 4, transfer device 5, separator 6, etc. and the developing sleeve 10b have a charging power supply circuit 8m as a high voltage power source.
, development bias? I! source circuit 8b, transfer power supply circuit 8c,
A high DC or AC voltage is applied from the separate power supply circuit 8d. Poor connection of the wiring of this high voltage power supply circuit, discharge wire 10a
Abnormal discharge conditions may occur due to disconnection of the ylOc 110d, leakage due to dirt or scratches on the discharge wire 1o, or improper installation of the photoreceptor drum 1 or developing device 4, but conventionally, there is no way to immediately detect this abnormality. The judgment was made by looking at the state of the image on the recording paper P printed out by the electrophotographic copying apparatus. [Problems to be Solved by the Invention] As described above, in the past, for example, an abnormal state of the high voltage power supply of an electrophotographic copying machine could not be known until the copied image was actually seen. As a result, the discovery of the above abnormal condition was delayed and the second problem occurred. This is dangerous because it may lead to the occurrence of a third defective state or malfunction of the control system of the device main body due to abnormal discharge. The present invention was made to solve this problem, and
It is an object of the present invention to provide an electrophotographic copying apparatus that is safe and has fewer failures and can detect discharge abnormalities in the high-voltage power supply circuit at an early stage.

[Means to solve the problem]

The above-mentioned factors include a charging electrode that charges the image carrier, a developing bias voltage that is applied during development, a transfer W1 pole that transfers the toner image on the image carrier onto the transfer paper, or the transfer paper. This is achieved by an electrophotographic recording apparatus characterized in that an abnormality is detected by monitoring the voltage and/or current of a high-voltage power supply used for at least one of the separation electrodes that separate the image carrier from the image carrier. . Embodiment The present invention will be described above with reference to the illustrated examples. Fig. 1 is a schematic diagram showing the internal configuration of an embodiment of the present invention, Fig. 2 is a block diagram showing the relationship between the abnormality detection circuit, high voltage power supply circuit, and control system, and Fig. 3 is the abnormality detection circuit of Fig. 2. FIG. 4 is a circuit diagram showing an example of a constant current power source used in the abnormality detection circuit of FIG. 2. FIG. In FIG. 1, numerals 1 to 5 indicate the same or equivalent parts as those of the conventional device shown in FIG. 5. In FIG. 8b is an abnormality detection circuit, 9c is an abnormality detection circuit for transfer power supply circuit 8c, 9d is a separate power supply circuit, ac
This is an abnormality detection circuit for L. As shown in FIG.
A high voltage is supplied to each discharge wire or developing sleeve 10 from a high voltage power supply circuit 8 consisting of send. In response to this abnormality notification signal 212, the control circuit 21 displays the abnormality on a display section of an operation panel (not shown), and performs #JIII, such as turning off the power supply circuit 82. The high voltage power supply circuit 8 includes a DC constant current power supply used for the charger 2, an AC constant voltage power supply used for the separator 6, and the like. In this embodiment, as an example, the power supplies shown in the table below were used, and set values and allowable ranges for the set values were set. An example of an abnormality detection circuit used for the DC constant current is shown in FIG. 3, and an example of an abnormality detection circuit used for the AC constant voltage power supply is shown in FIG. In the detection circuit shown in Fig. 3, R1 is a resistor for current value detection, 91 is an operational amplifier, 92 is a comparator for detecting excessive current values, 93 is comparator B for detecting undercurrent values, and 98a is for the upper limit of the allowable range. 96b is a reference voltage generator B197 that supplies a reference voltage corresponding to the lower limit of the allowable range (off day), and 212 is an abnormality notification signal of 0 or more. Therefore, when the high-voltage current supplied from the high-voltage power supply circuit 8 reaches a value outside the permissible range, the abnormality notification signal 212 is sent to the control circuit 21, so that it can be used as a DC constant current power supply. In the detection circuit of FIG. 4, symbols 96a, 96b, 97
are the same or equivalent parts as in Fig. 3, 94 is a comparator for detecting an excessive voltage value, 95 is a comparator B for detecting an undervoltage value, and 98 is an absolute value amplifier %R2 and C1.
is a resistor and a capacitor for smoothing the output from the absolute value amplifier, and the 8 power of the high voltage power supply circuit 8 that supplies AC high voltage to the discharge wire 10d of the separator 6 is double-wave rectified by the absolute value amplifier 98. After that, it is smoothed by the resistor R2 and the capacitor C1, and then the comparator ^94 and the humpator 89
5, when the value is outside the allowable range, it is detected and an abnormality notification signal 212 is sent to the control circuit 21 via an OR date 97. In this case, it is used as an AC constant voltage power supply. With the above configuration, when the high voltage supplied from the high voltage power supply circuit 8 reaches a value outside the permissible range, the abnormality notification signal 212 is sent to the control circuit 21. In all of the embodiments described above, the same abnormality notification signal 212 is sent using the ORDATE 97 whether the current or voltage of the supplied high voltage exceeds the upper limit of the allowable range or falls below the lower limit of the allowable range. However, off date 9
It goes without saying that the signal exceeding the upper limit from the comparator B96a and the signal below the lower limit from the comparator B96b may be separately sent to the control circuit 21 without providing the signal +11°. Of course, it is also possible to immediately detect an abnormal state of the developing bias, display it, and turn off the developing bias power supply circuit 8b.

【Effect of the invention】

As explained above, the electrophotographic copying apparatus of the present invention is provided with a circuit that immediately detects abnormalities in the high voltage or current supplied from the high voltage power supply circuit, and activates the control circuit. The second problem was that the discovery was delayed. t
It is possible to keep the failures to be minor without causing IS3 failures, and it is possible to obtain a safe electrophotographic copying apparatus with fewer failures. It goes without saying that the present invention can also be used in copying machines and other side image recording means.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the internal configuration of an embodiment of the present invention, Fig. 2 is a block diagram showing the relationship between an abnormality detection circuit, a high voltage power supply circuit, and a control circuit, and Fig. 3 is a block diagram showing the relationship between an abnormality detection circuit, a high voltage power supply circuit, and a control circuit. FIG. 4 is a circuit diagram showing an example of a detection circuit, FIG. 4 is a diagram showing an example of an abnormality detection circuit used in an AC fixing voltage power supply, and FIG. 5 is a schematic diagram showing the internal configuration of a conventional electrophotographic copying apparatus. In the figure, 1... photoreceptor drum, 2... charger, 3...
...Optical system, 4...Developer, 5...
Transfer device, 6... Separator, 7... Cleaning device, 8... High voltage power supply circuit, 9... Abnormality detection circuit, 21... Control circuit, 212...
Abnormality notification signal, D: Original, P: Recording paper. Applicant: Konishi Roku Photo Industry Co., Ltd. Figure 3 Figure 2 Purchase Notification Signal Figure 4 Figure 5

Claims (1)

[Claims] A charging electrode that charges the image carrier, a development bias voltage that is applied during development, a transfer electrode that transfers the toner image on the image carrier onto the transfer paper, or separation of the transfer paper from the image carrier. An electrophotographic recording apparatus characterized in that an abnormality is detected by monitoring the voltage and/or current of a high-voltage power supply used for at least one of the separation electrodes that performs the process.