JPH06318026A - High voltage power source for image forming device - Google Patents

Abstract

PURPOSE:To receive an output instruction value or an output monitor value from a high voltage power source which feeds back to a CPU by one system of receiving port of the CPU. CONSTITUTION:The high voltage power source 20 is constituted of a high voltage generation circuit 21, an output value detection circuit 23 and a switching circuit 24, and connected to the CPU 25 for controlling an image forming device. The output instruction value from the CPU 25 is inputted in the switching circuit 24, and the output monitor value from the detection circuit 23 is inputted in the switching circuit 24. The output instruction value and the output monitor value are selectively outputted from one terminal 24a of the switching circuit 24 according to a switching signal from the CPU 25 and received by one receiving port 25a of the CPU 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage power supply for an image forming apparatus for supplying power to a belt electrode or a developing device provided in an electrophotographic image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Generally, a copying machine, which is an electrophotographic image forming apparatus, comprises a platen on which a document is placed, a document irradiation lamp reciprocating below the platen, a reflecting mirror, and a fixed projection lens and a reflecting mirror. A scanning optical system that rotates, and a photoconductor that rotates by being charged with a predetermined potential by a band electrode,
A developing device for applying toner to the electrostatic latent image formed on the surface of the photoconductor by the scanning optical system to develop the electrostatic latent image, and a toner image on the surface of the recording paper which is a transfer material conveyed toward the surface of the photoconductor. A transfer electrode for transferring, a separation electrode and a removing electrode, a fixing device for fixing the toner image transferred on the surface of the recording paper, and a toner and paper dust remaining on the surface of the photoconductor after the transfer. And a cleaning device.

Then, desired toner images are successively recorded on the surface of the recording paper conveyed along a predetermined conveying path.

The cleaned photoreceptor is recharged according to a predetermined sequence and enters the next image forming process.

A control CPU provided in the copying machine
Check the output value of the high-voltage power supply and the function to instruct the high-voltage power supply to output from the CPU between the high-voltage power supply that supplies power to the strip electrode, developing device, transfer electrode, separation electrode, or removal electrode. C
The PU has a function of monitoring, and the output instruction value and the output voltage value and current value are constantly fed back to the CPU to confirm both data.

In connection with the conventional technique, for example, Japanese Patent Laid-Open No. 2-2282
Japanese Patent Publication No. 50 is disclosed.

[0007]

However, for example, C
When adding a function to check the output instruction value from the PU to the high voltage power supply, the CPU for controlling the copying machine is provided with a port for the output instruction value monitor to be added one by one in addition to the output monitor value receiving port. Need to increase. Therefore, each time one confirmation signal is added to each charging unit or developing device, the CPU needs a port corresponding to this, and if many confirmation signals are added in the copying machine, one CPU inevitably corresponds. Therefore, a plurality of CPUs or large-sized CPUs must be prepared, which is very disadvantageous in terms of space and cost. The present invention solves such a problem, and even if many confirmation signals are added in the image forming apparatus, it is possible to perform transmission and reception without increasing the number of receiving ports of the CPU for receiving this. The purpose is to provide a high-voltage power supply for use.

[0008]

This object is to provide at least a charging means, a transfer means, a separating means, an electrophotographic image forming apparatus,
In the high-voltage power supply in the apparatus for supplying electricity to the charge removing unit and the developing unit, a control C provided in the image forming apparatus
The same output is provided in the high-voltage power supply, which has a function of transmitting an output value from the CPU to the high-voltage power supply between the PU and the high-voltage power supply, and a function of checking the output value of the high-voltage power supply and monitoring it by the CPU. This is achieved by a high-voltage power supply for an image forming apparatus, which is provided with a switching circuit that selects either an output monitor value or an output instruction value from a terminal and feeds it back to the CPU.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is a block diagram showing the structure of a high voltage power source provided with a switching circuit shown in FIG. 1, a diagram showing the connection between a band electrode and a high voltage power source shown in FIG. A side cross-sectional view showing the configuration of the device will be described. However, the present invention is not limited to this embodiment.

As shown in FIG. 3, an electrophotographic image forming apparatus (hereinafter simply referred to as an image forming apparatus) 18 is provided with a platen glass P on which an original M is placed on the upper surface of the main body 1, and the platen glass P in the main body 1 is provided. A scanning optical device 2 is provided below. The scanning optical device 2 comprises a reciprocating document irradiation lamp 2a, a first mirror 2b, second and third mirrors 2c forming a V shape, a fixed projection lens 2d and a fourth mirror 2e. A photoconductor drum 3 is rotatably provided in the center of the inside of the main body 1 in the direction of the arrow, and in the periphery thereof, a belt electrode 4 for uniformly charging the photoconductor 3a along the rotation direction and a toner replenishing device. 5, the toner is replenished with toner, the developing device 6 including the developing sleeve 6a, the transfer electrode 7,
The separation electrode 8, the static elimination electrode 9, and the cleaning device 10 are sequentially arranged. Two kinds of recording papers of different sizes are housed in the paper feed cassettes 11 and 11 'and set in the main body 1. Reference numeral 12 denotes a first paper feed roller that feeds the recording paper stored in the paper feed cassette 11 to a standby position before the second paper feed roller 13, and a belt is provided to prevent double feeding of the recording paper. It is composed of rotating rollers 12a, 12a and a stop roller (also referred to as a separating roller) 12b. 13 is an appropriate timing so that the recording paper fed by the first paper feed roller 12 is temporarily stopped at the standby position, and then the leading edge of the visible image on the photoconductor 3a and the leading edge of the recording paper are aligned at the transfer position. The second paper feed roller 14 for re-feeding the paper toward the transfer position is a guide plate for guiding the recording paper fed by the first paper feed roller 12 to the position of the second paper feed roller 13. Reference numeral 15 denotes a conveying device that conveys the recording sheet after transfer to the fixing position, and the fixing device 16 includes a heating roller 16a and a pressure roller 16b. Reference numeral 17 denotes a paper discharge roller that discharges the recording paper after fixing to the outside of the main body.

When the copy button is operated in the above apparatus, the original M on the platen glass P is exposed and scanned by the scanning optical device 2, and an electrostatic latent image of the original M is formed on the photoconductor 3a of the photoconductor drum 3. It This electrostatic latent image is developed by the developing device 6.
Is converted into a visible image by the transfer electrode 7 and transferred to the recording paper fed from one of the paper feed cassettes 11 and 11 'of the main body 1. After the transfer, the recording sheet is separated from the photoconductor 3a by the separation electrode 8 and is fixed by the transport device 15.
The sheet is conveyed to 16, is fixed there, and is ejected by the ejection roller 17. In this way, desired toner images are successively recorded on the recording paper surface.

Next, the high voltage power source of the present invention will be described.

FIG. 2 shows, for example, a high-voltage power supply connected to the discharge wire 4a of the band electrode 4, 26 is an AC power supply for applying an AC voltage to the discharge wire 4a, and 27 is a DC power supply for superimposing a DC voltage on the AC voltage. Power.

Generally, the AC voltage, which is an AC component, is 7 to 8.
In the range of KV (Peak to Peak), the direct current voltage, which is a direct current component, is set in the range of 1 KV to 4 KV and is applied so as to be superimposed on the discharge wire 4a.

FIG. 1 is a block diagram showing the configuration of the high-voltage power supply and the connection with the control CPU of the image forming apparatus. In the high-voltage power supply 20, a high-voltage generation circuit 21, an output value detection circuit 23, and a switching circuit.
24 and are provided.

When the output instruction value previously stored in the CPU 25 for controlling the image forming apparatus 18 is input to the high voltage generation circuit 21 by PWM having a predetermined pulse width, the output terminal of the high voltage generation circuit 21. A predetermined voltage based on the output instruction value is applied from 22 to the band electrode 4, for example. The output voltage value or output current value that has been output is input to the output value detection circuit 23 indicated by the arrow for confirmation. The switching circuit 24 provided in the high voltage power source 20 has a C
The output instruction value data from the PU 25 is once input and fed back to the CPU 25. On the other hand, each output monitor value of the output voltage value or the output current value input to the output value detection circuit 23 described above is also input to the switching circuit 24 as indicated by an arrow.

Based on the switching instruction signal of the CPU 25, either the output instruction value or the output monitor value input to the switching circuit 24 is selectively taken out, and the terminal 24a.
To the receiving port 25 which is the PWM measuring terminal of the CPU 25
It is fed back to a. Therefore, in one receiving port 25a of the CPU 25, an output instruction value for the high-voltage power supply 20 and an output monitor value such as an output voltage value or current value are provided in the switching circuit.
It is fed back from one terminal 24a of 24.

Therefore, conventionally, a separate port was provided for confirming the output instruction value added outside the reception port for the output monitor value, and two systems were used to cope with this, but the switching circuit 24 of the present invention is used.
Due to the arrangement, the CPU 25 has one receiving port 25a
Now it is possible to receive both data.

The high-voltage power supply 20 of the present invention has been described as an example in which a high voltage is applied to the band electrode 4 of the image forming apparatus 18. However, in addition to this, the developing device 6, the transfer electrode 7, the separation electrode 8 or the static elimination electrode 9 is used. The output monitor value and the output instruction value of the voltage value and the current value applied to, for example, can also be received by the receiving port of the CPU 25 which is set to one system by the switching circuit 24 in the same manner as described above.

[0020]

According to the high voltage power supply provided with the switching circuit of the present invention, the output instruction value for the high voltage power supply from the CPU in the image forming apparatus and the output monitor value such as the output voltage value or current value is one of the switching circuit. Since it is possible to receive from one terminal to one receiving terminal of the CPU, even if the confirmation function of each part of the above device is added, the size of the CPU is not particularly increased, so that space or cost is reduced. It was a great advantage.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a high voltage power supply according to an embodiment of the present invention.

FIG. 2 is a diagram showing connection of a high voltage power supply.

FIG. 3 is a side sectional view showing the configuration of the image forming apparatus.

[Explanation of symbols]

 3 Photosensitive drum 4 Electrode 18 Image forming device 20 High voltage power supply 21 High voltage generation circuit 23 Output value detection circuit 24 Switching circuit 24a terminal 25 CPU 25a Reception port

Claims (1)

[Claims] 1. A control CPU provided in the image forming apparatus in a high-voltage power supply for supplying power to a charging means, a transfer means, a separating means, a discharging means, and a developing means of an electrophotographic image forming apparatus. , CP between the high voltage power supply
The output monitor value or the output instruction value from the same output terminal is provided in the high voltage power supply that has a function of transmitting an output value from U to the high voltage power supply and a function of confirming the output value of the high voltage power supply and monitoring it by the CPU. A high-voltage power supply for an image forming apparatus, comprising a switching circuit for selecting any one of them and feeding back to the CPU.