JPS6365939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device for transferring a toner image on a photoreceptor to a transfer material such as paper in an electrophotographic copying machine.

Conventionally, as a transfer means in this type of transfer device, a transfer material is brought into close contact with the surface of a photoreceptor on which a toner image has been formed, and a Kontron discharges from the back side of the transfer material to transfer the toner image. There is known a method in which a transfer material is pressure-bonded and transferred onto the surface of a photoreceptor on which a bias voltage is applied using a roller to which a bias voltage is applied.

However, since the transfer means in conventional transfer devices generally brings the transfer material into direct contact with the photoreceptor surface, it is necessary to peel the transfer material from the photoreceptor surface, which may damage the photoreceptor surface when the transfer material is peeled off. In addition, when a paper jam occurs due to a mistake in peeling off the transfer material, the surface of the photoreceptor may be damaged.

The present invention has been devised in view of the above circumstances, and is capable of transferring a toner image on a photoreceptor to a transfer material without bringing the transfer material into direct contact with the surface of the photoreceptor. The purpose of the present invention is to provide a transfer device for an electrophotographic copying machine that prevents damage to the surface of a photoreceptor when a paper jam occurs due to a peeling error. A charging device 2 and an exposure device 3 for forming a charged electrostatic charge image A, and a developing device 4 for attaching toner of opposite polarity to the electrostatic charge image A to the electrostatic charge image A to form a toner image B. , a discharge electrode 10 that performs corona discharge of opposite polarity to the toner charging polarity onto the toner image formed on the photoreceptor surface 1a, and a toner charging polarity that transfers the toner image R from the photoreceptor surface 1a after the corona discharge. A conductive intermediate transfer member connected to a potential of the same polarity as and disposed opposite to the photoreceptor surface 1a with a gap therebetween, and a transfer material is brought into close contact with the intermediate transfer member to transfer the toner image onto the transfer material. The apparatus is characterized in that it includes a transfer means for transferring.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a static eliminator 6, a cleaning device 7, etc. are sequentially arranged around the photoreceptor 1, as in the conventional case. ing.

As shown in FIG.
A and a pressure roll 9 are disposed facing each other at a predetermined distance so as not to come into contact with the conductive roll 8.
A discharge corotron 1 serving as a discharge electrode is placed in pressure contact with the conductive roll 8 and the developing device 4.
0 is disposed facing the photoreceptor surface 1a.

In FIG. 1, 11 is an insulated guide, 12 is a pressing spring for pressing the pressing roll 9 against the conductive roll 8, 13 is a sheet of paper to be a transfer material,
14 is a peeling device for peeling the paper 13 from the conductive roll 8.

The conductive roll 8 is connected to a potential having the same polarity as the toner charging polarity, which will be described later, and the discharging corotron 10 applies a corona discharge having a polarity opposite to the toner charging polarity to the surface of the photoreceptor and the toner image after development. It is configured so that it will be carried out.

As shown in FIG. 2, an electrostatic charge image A is formed on the photosensitive layer 16 on the substrate 15 forming the photoreceptor 1 in accordance with the original image. The charged toner is adhered and developed, and as shown in FIG. 2, a toner image B corresponding to the electrostatic charge image A is formed.

Then, corona discharge with a polarity opposite to the toner charging polarity is performed on the toner image RO and the photoreceptor surface 1a by the discharging corotron 10, and as shown in FIG. 3, after the toner charging polarity is reversed, Become.

At this time, since the photosensitive layer 16 is electrically charged, the toner image 2 is easily separated from the photosensitive layer 16, that is, the photoreceptor surface 1a.

On the other hand, on the photoreceptor surface 1a, that is, the photosensitive layer 16,
As described above, a voltage of the same polarity as the toner charging polarity, that is, a voltage is applied to the conductive rolls 8 which are disposed facing each other with a gap between them, so that static electricity is generated between the conductive rolls 8 and the toner charged on the photosensitive layer 16. Because electric attraction is generated,
The aforementioned toner image B is transferred to the conductive roll 8,
The toner image transferred to the conductive roll 8 is transferred to the paper 13 fed between the conductive roll 8 and the pressure roll 9 by the pressing force of the pressure roll 9 in the same manner as in pressure fixing. .

The paper 13 to which the toner image B has been transferred is peeled off from the conductive roll 8 by a peeling device 14 .

As shown in FIG. 4, if a heater 17 connected to a power source 18 is provided inside the conductive roll 8 to control its surface temperature to the toner fusing temperature, the conductive roll 8 can also perform a heat fixing action. The toner image B can be transferred and thermally fixed onto the paper 13 at the same time. Further, according to the embodiment described above, the toner image on the conductive roll 8 is transferred onto the paper 13 by the pressing force of the pressure roll 9; The means is not limited to this, but it may be a conventional means for transferring the toner image on the surface of the photoreceptor onto paper, such as, for example, as described above, the paper is brought into close contact with the surface of the photoreceptor, and the transfer is performed by discharging the toner image from the back side of the paper using a corotron. Similarly to the above, it is possible to employ any conventionally known transfer means, such as bringing the paper 13 into close contact with the toner image on the conductive roll 8 and transferring it by discharging it with a corotron from the back side. be.

As described above, the present invention includes a charging device 2 and an exposure device 3 for forming an electrostatic charge image A charged to a predetermined polarity in accordance with an original image on a photoreceptor surface 1a;
A developing device 4 that attaches toner of opposite polarity to this electrostatic charge image A to form a toner image B.
, a discharge electrode 10 that performs corona discharge with a polarity opposite to the toner charging polarity onto the toner image formed on the photoreceptor surface 1a, and a
a conductive intermediate transfer member connected to a potential of the same polarity as the toner charging polarity for transferring the toner image from a to the photoreceptor surface 1a, and facing the photoconductor surface 1a with a gap therebetween;
Since the intermediate transfer member is provided with a transfer means for bringing the transfer material into close contact with the transfer material and transferring the toner image to the transfer material, the transfer material can be transferred onto the photoreceptor surface 1a without directly contacting the photoreceptor surface 1a with the transfer material. The toner image can be transferred to the transfer material, and therefore, unlike the conventional method in which the toner image is transferred to the transfer material by bringing the transfer material into direct contact with the photoreceptor surface 1a, when the transfer material is peeled off, or when the transfer material is peeled off incorrectly, the paper Photoconductor surface 1 when clogged
It does not cause any harmful effects such as damage to a. Further, since the toner image on the photoreceptor surface 1a is charged to the opposite polarity by the discharge electrode 10, the photoreceptor 1
The toner image B has the same polarity as the photoreceptor surface 1a, making it easier to separate from the photoreceptor surface 1a, and the toner image B and the intermediate transfer member have different polarities, creating electrostatic attraction between them. is efficiently transferred to
Transfer efficiency is improved and copies with excellent image quality can be obtained.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams of its operation, and FIG. 4 is a partially broken explanatory diagram showing another embodiment of the conductive roll. 1 is a photoconductor, 1a is a surface of the photoconductor, 8 is a conductive intermediate transfer member, 10 is a discharge electrode, and 13 is paper.

Claims (1)

[Claims] 1 A charging device 2 and an exposure device 3 for forming an electrostatic charge image A charged with a predetermined polarity according to the original image on the photoreceptor surface 1a, and an electrostatic charge image A having a polarity opposite to that of the electrostatic charge image A, A developing device 4 that adheres toner to form a toner image (R), a discharge electrode 10 that performs a corona discharge of opposite polarity to the toner charging polarity onto the toner image (R) formed on the photoreceptor surface 1a, and a A conductive intermediate transfer member connected to a potential of the same polarity as the toner charging polarity for transferring the toner image B from the photoreceptor surface 1a and disposed opposite to the photoreceptor surface 1a with a space therebetween; A transfer device for an electrophotographic copying machine, comprising a transfer means for transferring a toner image to a transfer material by bringing the transfer material into close contact with the transfer material.