JPS58105273A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To remove a cleaning member for deteriorating a photosensitive material of a photoreceptor, by executing the transfer by DC bias in the first cycle, and executing the cleaning by AC bias in the second cycle, by an intermediate transfer body. CONSTITUTION:A transfer device 6 is constituted of an intermediate transfer body 8 and a transfer body 9, and either an electric power supply 12 or an electric power supply 13 is connected to the transfer body 8. To the transfer body 9, DC bias of the same polarity as a photoreceptor 1 is applied from an electric power supply 14, and it is provided so as to be attachable and detachable to and from the transfer body 8. In the first cycle, DC bias of the same polarity as the photoreceptor 1 is applied to the transfer body 8 from the electric power supply 12 and the transfer is executed. In the second cycle, the transfer body 9 is separated, and AC bias to which DC has been superposed from the electric power supply 13 is applied to the transfer body 8, a toner of positive and opposite polarity of the photoreceptor 1 is attracted, and cleaning is executed exactly. Therefore, it is possible to remove a cleaning member for deteriorating a sensitized material of the photoreceptor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic apparatus, and more specifically, in the first cycle of a photoreceptor, charging, exposure, transfer, and transfer steps are performed, and in the second cycle, charge is removed from the surface of the photoreceptor, and a cleaning process is performed. The present invention relates to an electrophotographic apparatus that performs a two-cycle, one-copy process.

Conventionally, these seven types of electrophotographic IIT have generally been equipped with devices for carrying out each process around a photoreceptor.

The transfer device used to carry out the above-mentioned transfer process is one in which the paper is brought into close contact with the surface of the photoconductor, and a cicorotron is used to discharge electricity between the sheets to transfer the paper, and a roller to which a bias voltage is applied is used to transfer the paper to the surface of the photoconductor. There are known methods in which the image is transferred by crushing it.

”-However, with any transfer device, the paper is transferred to the surface of the photoreceptor.
Since the paper was designed to be touched for 1 m, it was necessary to peel the paper from the photoconductor surface, and the photoconductor surface was damaged when the paper was peeled off).
When a paper jam occurs due to paper peeling, etc., the surface of the photoreceptor is damaged, resulting in a problem.

Therefore, electrophotography has been developed that allows the toner image on the photoreceptor to be transferred without the paper coming into contact with the photoreceptor surface, so that the surface of the photoreceptor is not damaged when the paper is peeled off or when the paper is jammed after being peeled off. Using a transfer device of a copying machine, specifically an intermediate transfer member, toner gI! on the surface of the -1 photoreceptor is transferred. A transfer device is known that transfers the image to an intermediate transfer member and then retransfers it to a sheet of paper.

However, pressing the intermediate transfer member against the surface of the photoreceptor is disadvantageous in terms of space and cost. It is very uneconomical to do so.

On the other hand, as a cleaning am for carrying out a cleaning process, one in which a cleaning member such as a blade is brought into contact with the surface of a photoreceptor is known.

However, this structure has the disadvantage that the cleaning member deteriorates and peels off the sensitive material on the surface of the photoreceptor, resulting in a shortened lifespan of the photoreceptor.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an electronic triple-transfer device that is capable of carrying out a transfer process and a cleaning process using an intermediate transfer member that is pressed against the surface of a photoreceptor. marry

The present invention will now be described in detail with reference to FIG. 1ili'.

There is a charge of 1 around the photoreceptor 1! [2. An image exposure device 3, a developing device 4, a static eliminator 5, a transfer device 6, etc. are arranged in this order.

The transfer device 6 presses the intermediate transfer body 8 and the transfer body 9,
The intermediate transfer member 8 is pressed against the photoreceptor surface FjjJ lm.

The intermediate transfer body g has an insulating layer 8b on the surface of the conductive layer 8a, and the conductive layer 8 is connected to either the first power source 12 or the second power source 13 via the switch 11. Connected by the copy cycle tying signal.

The transfer body 9 is a roll-shaped conductive layer with an insulating layer provided on the surface of the conductive layer 9m. It is connected to the aFiJIg3 power supply 14.

The first power source 12 has the same polarity as the photoreceptor charging polarity (
It becomes a DC bias power supply with the opposite polarity to the toner image, and
Power source 13 Fi AC bias it source 131 and DC bias power source 13 with the same polarity as the photoreceptor charging polarity! Toyoshi Sei), 3rd
The power supply 14 is the same DC bias power supply as the first power supply 12, and has a voltage of 4i16 from the first power supply port 2.

Then, the paper 1o is inserted and conveyed into the nip area between the intermediate transfer body 8 and the transfer body 9.

The cleaning device 20 #i is equipped with a cleaning member 21 such as a brush that comes into contact with the intermediate transfer body 8 .

Said transcript? t1 As shown in FIG. 2, the swing lever 15 is supported via the support shaft 1, and the swing lever 15 is urged to swing upward by a spring 16, and one cam 17 comes into contact with the swing lever 15.
When the lower @17m of the cam 17 comes into contact with the swing lever 15, the second
As shown by the solid line in the figure, the position is in pressure contact with the intermediate transfer body 8)
When the height 1177b of cam #7 comes into contact with the cam #7, the cam #7 is in a position separated from the intermediate transfer body 6 as shown by the imaginary line in FIG.

The operation of the cam 17 is controlled by a timing signal (not shown) from the copying cycle.

Therefore, the 101st rotation of the photoreceptor (that is, the cycle)
The charging device 2, the exposure device fa13, and the image forming device 4 operate sequentially to carry out charging, image exposure, and block image processes, and an electrostatic charge image corresponding to the original image and its electrostatic charge are formed on the photoreceptor surface [11aKti]. A toner writing opening corresponding to image A is formed.

When the toner particles reach the nip area with the intermediate transfer body g, they are adhered to and transferred to the intermediate transfer body 8, and transferred again to the paper 10 being conveyed in the direction of the arrow in the nip area with the transfer body 9.

At this time, the cam 17 and the switch 1 are controlled by a timing signal (not shown), so that the transfer body 9 is in pressure contact with the intermediate transfer body 8, and the conductive layer 8m of the intermediate transfer body 8
is connected to the first power supply 12.

For this purpose, a DC bias voltage having the same polarity as the photoreceptor charging polarity is applied to the intermediate transfer member 8, so that the photoreceptor surface Ia
The upper reverse polarity toner 8 does not adhere to the intermediate transfer member 8, and the fogging phenomenon due to the reverse polarity toner adhesion does not occur on the copy, so that an enviable copy can be obtained.

In other words, the reverse polarity toner is generated due to developer deterioration and is charged to the same polarity as the photoreceptor charge polarity, and as shown in FIG. -cI (toner image) adheres to the image area 1' where the surface potential of the photoreceptor is high.

Therefore, if a DC bias voltage of the same polarity as the photoconductor charging polarity is applied to the intermediate transfer member 8, toner of opposite polarity will repel each other and will not be transferred, and only toner of positive polarity will be transferred.

Then, when the photoconductor 1 rotates once and reaches the second rotation (second cycle), the static eliminator 5 operates to carry out the static elimination process, and the toner remaining on the photoconductor surface 1a is removed from the photoconductor surface 1a. ] It becomes easier to leave.

At this time, the operation of the cam 17 and the switch 11 is controlled by a timing signal not shown, and the conductive layer εa/d of the intermediate transfer body 8 is connected to the second power supply 13, and the transfer body 9 is moved as shown in FIG. It is moved tK away from the intermediate transfer body S.

When the residual toner reaches the nip area with the intermediate transfer body 8, it is attached to the intermediate transfer body 8, and the front surface 1a of the photoconductor is cleaned.

At this time, the intermediate transfer body 8 is connected to the second power source 13 and an AC bias voltage superimposed on the current bias voltage tube is applied, so that the positive and reverse polarity toners remaining on the photoreceptor surface 1 are transferred to the intermediate transfer body 13. It is attracted to the body 8, and the surface 1m of the photoreceptor is reliably bent.

The bias voltage applied to the intermediate transfer body 8 is the fifth
With the waveform shown in the table in the figure], when a positive half wave +V is applied, the positive polarity toner of θ is attracted, and when the negative half wave -V is applied, the opposite polarity toner of ■ is attracted. .

Since the transfer body 9 has been moved to a position apart from the intermediate transfer body 6, the residual toner attached to the intermediate transfer body 6 is removed by the cleaning member 21 and deposited inside the housing 22. do.

Note that the second power source I3 may be configured as an AC bias power source to apply an AC bias voltage.

As described above, the present invention is economical because the transfer process and cleaning process can be performed using the intermediate transfer member 8, and there is no need to provide a cleaning member around the photoreceptor 1. Moreover, since the cleaning member does not deteriorate or peel off the photosensitive material on the surface of the photoreceptor, the life of the photosensitive material can be improved.

In addition, when performing the transfer process, a DC bias voltage having the same polarity as the photoconductor charging polarity is applied to the intermediate transfer body 8, so that
The reverse polarity toner on the photoreceptor surface 11 is not attracted to the intermediate transfer member 8, and it is possible to prevent the occurrence of the fogging phenomenon due to the reverse polarity toner adhering to the copy.

In addition, when performing cleaning @, an AC bias voltage is applied to the intermediate transfer member S, so that the toner of opposite polarity and the toner of positive polarity remaining on the sensing body surface Is can be adsorbed.
The photoreceptor surface 1- can be reliably cleaned.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall front view, FIG. 2 is an explanatory diagram of installing the transfer body, FIG. 3 is an explanatory diagram of reverse polarity and positive polarity toner, and FIG. FIG. 5, which is an explanatory diagram of the operation during cleaning, is a table showing the waveform of the bias voltage applied to the intermediate transfer body during cleaning. 1 is a photoreceptor, #- is a table, gFi intermediate zero body, and 10 is paper. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto

Claims (1)

[Claims] Electrophotography in which charging, image exposure, and development processes are performed in the first cycle using photoreceptor 1, and charge removal and cleaning processes on the photoreceptor surface fa are performed in the second cycle! At position j, an intermediate transfer member ε faces the photoreceptor surface Lm.
In the first cycle, a transfer process is carried out to transfer the toner image on the photoreceptor surface 1a to the paper 10, and in the second cycle, a cleaning process is carried out to remove the residual toner on the sensor surface M1. , the electrophotographic f! is characterized in that the bias voltage applied to the intermediate transfer member g is a direct current voltage having the same polarity as the photoreceptor charging polarity, and the second cycle is an alternating current voltage. Place.