JPH0498278A - electrophotographic equipment - Google Patents

Abstract

PURPOSE:To carry out a transfer operation and a destaticizing operation without generating ozone by carrying out the transfer operation and the destaticizing operation utilizing triboelectricity without utilizing a corona discharge phenomenon. CONSTITUTION:When a toner image formed on a photosensitive drum 2 is transferred to a transfer material P, a backside of a transfer material P is frictionally engaged with a transfer brush 31 upstream of a photosensitive drum 2 in a transfer material carrying direction. The brush 31 is formed to be on the same side of polarity (negative side) as the electrification polarity of the toner image, and since the backside of the transfer material P is electrified to the reverse polarity as the toner image (positive electrification), the toner image is transferred from the beforementioned drum 2. The brush 31 has bias voltage of a reverse polarity as the toner image impressed on it, and the transferring function is further improved. Then, the backside of the transfer material P part is frictionally engaged with the destaticizing brush 41, and the brush part 41 is formed to be the reverse polarity side (positive polarity side) as the electrification polarity of the toner image, and the backside is triboelectrified to the same polarity as the toner image and destaticizing is carried out by neutralizing the electrical charge (positive electrical charge). Therefore, in the transfer device 30 and the destaticizing device 40, since the transferring and destaticizing operations are carried out utilizing triboelectricity between each contact member and the transfer material P, no ozone is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electrophotographic devices such as laser printers, copying machines, and facsimiles.

[Conventional technology] FIG. 4 shows the general configuration of a conventional electrophotographic apparatus.

In the figure, 1 is an apparatus main body, and inside the apparatus main body 1, an image carrier (2), a charging device 3. Optical system 4. Developing device5. Fixing device6. A transfer device 10, a static eliminator 20, and the like are provided.

When printing using this electrophotographic apparatus, the peripheral surface of the photosensitive drum 2 as an image carrier is uniformly charged (for example, -650V) by the charging device 3. Then, the peripheral surface of the charged photosensitive drum 2 is irradiated with a laser beam 4a based on print data from the optical system 4. Toner in the developing device 5 is electrostatically adhered to the laser beam irradiated area. Here, the developing device 5 has a bias voltage (for example, -650V).
is being applied, and the toner is charged (-650V).

Then, in the transfer device 10, the back surface of the transfer material P fed through the paper feed unit 7 is charged with a charge (positive charge) of the opposite polarity to that of the toner by utilizing the corona discharge phenomenon, and the laser beam 4a The toner f image attached to the irradiated area is transferred from the photosensitive drum 2 to the surface of the transfer material P. Note that the transferred toner image is fixed onto the transfer material P by the fixing device 6.

By the way, normally, the transfer device 10, as shown in FIG.
In the figure, the shield case 11 is extended in a direction perpendicular to the plane of the paper.
Discharge wire 1 stretched inside this shield case 11
2 and a power supply device 13 for applying a high voltage (for example, +5 kV>) having a polarity opposite to that of 1 henna to the discharge wire 12.

On the other hand, the static eliminator 20 operates on a transfer material P to which the toner image has been transferred.
This is a means of removing static electricity from a portion. Specifically, the static eliminator 2
0 is a charge supplied to the back surface of the transfer material P on which the toner image has been transferred using a corona discharge phenomenon in the transfer device 10 by charging the back surface of the transfer material P with the same polarity (negative charge) as that of the toner image. It is formed to neutralize (positive charge) and eliminate static electricity. The static eliminator 20 includes a shield case 21 similar to the transfer device 10. Discharge wire 22
and the power supply device 23, etc.

[Problems to be Solved by the Invention] However, the electrophotographic apparatus described above has the following problems.

0 Ozone, which is harmful to the human body, is generated.

During printing, a large amount of ozone is generated as a result of corona discharge from each of the discharge wires 12 and 22 of the transfer device 10 and the static eliminator 20, but ozone has an adverse effect on the human body and poses a problem in terms of the working environment.

Therefore, for example, a roller-type transfer device 10 that can perform a transfer operation without generating ozone has been put into practical use. As shown in FIG. 6, this roller type transfer device presses an elastic roller 15 whose circumferential surface is made of conductive rubber or the like against the photosensitive drum 2, and applies a high voltage of about 1 kV to the elastic roller 15. is applied, and one henna image is transferred onto the transfer material P sent between the roller 15 and the photosensitive drum 2 by the electrostatic attraction force acting between the roller 15 and the toner image on the photosensitive drum 2. However, in such a roller-type transfer device, since the elastic roller 15 is used by pressing the photosensitive drum 2, the toner remaining on the photosensitive drum 2 adheres to the surface of the roller, and this adhered toner prevents the transfer. There may be an inconvenience that the back side of the material P gets dirty.

■It is difficult to downsize and reduce costs.

Recently, in order to expand the field of use of electrophotographic equipment, efforts have been made to simplify the structure, reduce the size, and lower the cost.
There is a need to aim for the improvement of Therefore, the transfer device 10 and the static eliminator 2, which are the main components of the electrophotographic device,
0 as well, there is a strong demand for smaller size and lower cost. However, both devices 10.20 have shield cases 11.20 and 11.20 in order to cause corona discharge to the transfer material P. ．． 21, and it is difficult to achieve miniaturization and low cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic apparatus that can perform transfer operations and static elimination operations without generating 11 ozone under the above circumstances, and that can be made smaller and lower in cost.

[Means for Solving the Problems] The present invention includes a transfer device that transfers a henna image not formed on an image carrier onto a transfer material, and a transfer device that is disposed downstream of the transfer device in a transfer material conveyance direction and that transfers a henna image that is not formed on an image carrier to a transfer material. In the electrophotographic apparatus, the transfer device includes a transfer contact capable of frictionally charging the back surface of the transfer material by frictionally engaging with the back surface of the transfer material upstream of the image carrier in the transfer material conveyance direction. Equipped with parts.

and at least a portion of the transfer contact member that comes into contact with the transfer material is formed to have the same polarity as the charged polarity of the toner image on the frictional charging chain between the transfer material and the static eliminator. is provided with a static elimination contact member capable of frictionally charging the back surface of the transfer material by frictionally engaging with the back surface of the transfer material at a position a predetermined distance downstream from the transferred portion of the image carrier in the transfer material conveying direction, and At least a portion of the static elimination contact member that comes into contact with the transfer material is formed to have a polarity opposite to the charged polarity of the toner image due to the frictional electrification series between the charge removal contact member and the transfer material. .

[Function] In the present invention, when a toner image formed on an image carrier is transferred to a transfer material, the back surface of the transfer material is frictionally engaged with a transfer contact member upstream from the image carrier in the transfer material conveyance direction. be done. Here, the portion of the transfer contact member that comes into contact with the transfer material is formed to have the same polarity as the charging polarity of the toner image on the frictional charging series between the transfer material and the back surface of the transfer material. is frictionally charged to have a polarity opposite to that of the toner image, and the toner image is transferred from the image carrier to the surface of the transfer material.

At this time, since the transfer contact member is provided upstream of the image carrier in the transfer material conveyance direction and does not come into contact with the image carrier, it is not contaminated by toner or the like remaining on the image carrier. Therefore, the back surface of the transfer material is not contaminated by the transfer contact member.

Next, the back surface of the transfer material is frictionally engaged with the static elimination contact member at a position a predetermined distance downstream in the transfer material conveyance direction from the transferred region of the image carrier. Here, the part that comes into contact with the static elimination contact member is formed to have a polarity opposite to the charging polarity of the toner 1 in the friction and frictional electrification series with the transfer material, so the transfer material The back surface is triboelectrically charged to have the same polarity as the toner image, and the charge (positive charge) supplied to the back surface is neutralized in the transfer device to perform static elimination.

In this way, in the above-mentioned transfer device and static eliminator, the transfer work and static eliminator work are performed using the frictional electricity generated between each contact member and the transfer material without using the corona discharge phenomenon. Does not occur. In addition, parts such as a shield case for corona discharge are not required, and miniaturization and cost reduction can be achieved.

[Example] An embodiment of the present invention will be described based on the drawings.

The electrophotographic apparatus according to this embodiment is an electrophotographic apparatus of a reversal development type, and is configured to perform a transfer operation and a static elimination operation using frictional electricity. Specifically, as shown in FIGS. 1 and 2, the present electrophotographic apparatus includes an apparatus main body 1. Image carrier (photosensitive drum 2), charging device 3. Optical system 4. Developing device5. Transfer device 30. It is configured to include a static eliminator 40, a support member 51, and the like.

Components that are the same as those shown in FIGS. 4 to 6 are denoted by the same reference numerals, and their explanations will be omitted or simplified.

Here, the transfer device 30 frictionally engages with the transfer material P and frictionally charges the transfer material P to a polarity opposite to that of the toner image on the photosensitive drum 2 (i.e., positive polarity), thereby transferring the toner image onto the transfer material P. It is a means of transferring onto.

Specifically, the transfer device 30 includes a transfer contact member that can frictionally engage with the back surface of the transfer material P and frictionally charge the back surface of the transfer material P upstream of the photosensitive drum 2 in the transfer material transport direction, and the transfer contact member that can frictionally charge the back surface of the transfer material P. At least a portion of the member that comes into contact with the transfer material P is formed to have the same polarity as the charging polarity of the toner image on the frictional charging series between the member and the transfer material P.

In this embodiment, the transfer contact member is the transfer brush 3.
It is formed from 1. Since the brush portion 31a of the transfer brush 31 has negative polarity since it is a 1-toner image, it is formed to be on the negative polarity side in the frictional charging series between it and the transfer material P. More specifically, the brush portion 31a of the transfer brush 31 is made of a material in which conductivity is imparted by dispersing carphone in polyester. Note that during the transfer operation, a bias voltage (for example, +1 kV) having a polarity opposite to that of the toner image is applied to the transfer brush 31 using a power supply device 33 in order to further improve the transfer performance.

On the other hand, the static eliminator 40 operates on a transfer material P to which the toner image has been transferred.
Means for frictionally engaging with the back surface of the portion to charge the transfer material P to the same polarity as the toner image, thereby neutralizing and eliminating the charge (i.e., positive charge) supplied to the transfer material P in the transfer device 30 It is.

Specifically, the static eliminator 40 frictionally engages with the back surface of the transfer material P at a position a predetermined distance downstream in the transfer material conveyance direction from the transfer target portion 2a of the photosensitive drum 2, and is capable of frictionally charging the back surface. A contact member for static elimination is provided, and at least a portion of the contact member for static elimination that contacts the transfer material P is on the opposite polarity side to the charging polarity of the toner image on the frictional charging series between the contact member and the transfer material P. is formed. In this embodiment, the static eliminating contact member is formed of a static eliminating brush 41. Since the toner image has negative polarity, the brush portion 41a of the static elimination brush 41 is formed so as to be on the positive polarity side in the frictional charging series between the brush portion 41a and the transfer material P.

Furthermore, the support member 51 positions and fixes the transfer contact member (31) near the photosensitive drum 2, and also moves the static elimination contact member (41) downstream from the transfer target area 2a of the photosensitive drum 2 in the transfer material conveyance direction. This is a means for positioning and fixing at a position separated by a predetermined distance. In this embodiment, five transfer material kite surfaces are formed using the upper surface of the support member 51 in order to achieve downsizing and cost reduction by sharing parts.

Next, the effect will be explained.

When transferring the toner image formed on the photosensitive drum 2 to the transfer material P, the back surface of the transfer material P is frictionally engaged with the transfer brush 31 upstream from the photosensitive drum 2 in the transfer material conveyance direction. Here, the transfer brush 31 is formed to have the same polarity as the charging polarity of the toner image (that is, the negative polarity side) in the frictional charging series ↓ between the transfer brush 31 and the transfer material P, so that the back surface of the transfer material P is It will be charged in the opposite phase to the toner image ('i charge),
A toner image is transferred from the photosensitive drum 2 onto the surface of the transfer material 2. At this time, the transfer brush 31 is supplied with a bias voltage (+1
kV> is applied, further improvement in transfer performance is guaranteed.

Next, the back surface of the portion of the transfer material P onto which the toner image has been transferred is frictionally engaged with the static elimination brush 41 . Here, static elimination brush 4
The brush portion 41 of No. 1 is formed so as to have a polarity opposite to that of the toner No. 1 (i.e., positive polarity side) on the frictional charging series between the brush portion 41 and the transfer material P. The back side is frictionally charged to the same polarity as the toner image and transferred to the transfer device 3.
At 0, the charge (positive charge) supplied to the back surface is neutralized and static electricity is removed.

As described above, in the transfer device 30 and the static eliminator 40,
Each contact member (31,
41) and the transfer material P to perform the transfer operation and the static elimination operation, so no ozone is generated. Furthermore, the transfer brush 31 is provided upstream of the photosensitive drum 2 in the transfer material conveyance direction, and does not come into contact with the photosensitive drum 2 . Therefore, the transfer brush 31 is connected to the photosensitive drum 2.
It will not be contaminated by toner etc. left on the surface.

As a result, the back surface of the transfer material P is not soiled by the transfer brush 31.

According to this embodiment, the transfer device 30 frictionally engages with the back surface of the transfer material P upstream of the image carrier (photosensitive drum 2) in the transfer material conveyance direction, and is capable of frictionally charging the back surface. A contact member (transfer brush 31) is provided, and at least a portion (31a) of the transfer contact member (31) that comes into contact with the transfer material P adjusts the charging polarity of the toner image on the frictional charging series between the transfer material P and the transfer material P. The static eliminator 40 is formed to have the same polarity as the back surface of the transfer material P at a position a predetermined distance downstream in the transfer material conveyance direction from the transferred region (2a) of the image carrier (2). A static elimination contact member (static elimination brush 41) capable of frictionally engaging with and frictionally charging the back surface thereof, and at least a portion (41a) of the static elimination contact member (41) that contacts the transfer material P or the transfer material Since it is formed so that the polarity is opposite to that of the toner image on the triboelectrification series between P and P, it is possible to perform transfer work and charge removal work without generating ozone, and it is also possible to reduce the size and Cost reduction can be achieved.

Further, since the transfer contact member (31) does not come into contact with the photosensitive drum 2 and is not contaminated by toner or the like remaining on the drum 2, there is no need to provide a special cleaning device. It is also possible to easily make the device smaller and lower cost.

In addition, a contact member for transfer (31) and a contact member for static elimination (
41) are integrated via the support member 51, it is possible to easily assemble the re-contact member <31.41) to the image carrier (2) while maintaining a constant positional relationship. Ru. Thereby, the transfer work and the static elimination work can be performed smoothly without mutual interference. Further, since the re-contact members (31, 41) are integrated via the support member 51, installation space can be saved, and miniaturization and cost reduction can be achieved.

Furthermore, the transfer contact member is composed of the transfer brush 31,
In addition, since the contact member for weight removal is configured with the static elimination brush 41, the re-contact members (31, 41) can be brought into surface contact with the back surface of the transfer material P so that the contact area is increased, and the back surface of the transfer material P is evenly coated. And it can be reliably charged.

Therefore, transfer performance and static elimination work can be improved.

In particular, in this embodiment, the power supply device 33 is used to apply a bias voltage (
For example, +1 kV) is applied, so the transfer performance can be further improved.

Note that even when the power supply device 33 is used, there is no need to increase the bias voltage, so miniaturization and cost reduction can be easily achieved.

Furthermore, since each brush 31a, 41a of the transfer brush 31 and the static elimination brush 41 has flexibility, it can be brought into contact with the transfer material P without strict positioning during assembly. Therefore, assembly becomes easy.

In the above embodiment, the transfer contact member and the static elimination contact member are connected to the transfer brush 31. Although the brush 41 is constructed from the static eliminating brush 41, it may be constructed in any manner as long as it can frictionally engage with the back surface of the transfer material P and frictionally charge the back surface.

For example, the transfer contact member may be composed of a rotating brush 35 as shown in FIG. Specifically, the rotating brush 35 includes a rotatably provided shaft 36 and a conductive and flexible brush 37 implanted on the circumferential surface of the shaft 36. The brush 37 is formed to have the same polarity as the charging polarity of the 1 henna image on the photosensitive drum 2 on the frictional charging line between the brush 37 and the transfer material P.

In a transfer device equipped with such a rotating brush 35, the back surface of the transfer material P upstream of the photosensitive drum 2 in the transfer material conveying direction is rubbed by the rotating brush 35 and positively charged, and the surface of the transfer material 2 is charged with a positive charge from the photosensitive drum 2. The toner image is transferred. At this time, if the rotating brush 35 is actively rotated using a driving means, the back surface of the transfer material P can be more effectively triboelectrically charged.

Similarly, the static elimination brush 41 may be formed using a rotating brush (not shown) that is formed to have a polarity opposite to the charged polarity of the toner image on the frictional charging line between it and the transfer material P. .

Furthermore, although at least the portion of the transfer contact member that contacts the transfer material P (such as the brush 31a of the transfer brush 31) is made of a material obtained by dispersing carphone in polyester and imparting conductivity, it is possible to It may be formed in any manner as long as it has the same polarity as the charging polarity of the toner image on the photosensitive drum 2 on the frictional charging series.

In addition, at least the portion of the static elimination contact member that contacts the transfer material P (brush 41a of the static elimination brush 41) is formed from polyamide, but due to the frictional charging series between the static elimination contact member and the transfer material P, the charged polarity of the toner image is opposite to that of the toner image. As long as it is on the polar side, it may be formed in any way.

Further, it is also possible to apply a bias voltage having the same polarity as the charged polarity of the toner image to the static elimination contact member (41) to more effectively eliminate static electricity.

Although the present invention has been applied to an electrophotographic apparatus using a reversal development method, it can also be applied to an electrophotographic apparatus using a regular development method.

[Effect of the invention 1] According to the present invention, the transfer work and the static elimination work are performed using triboelectricity without using the corona discharge phenomenon, so the transfer work and the static neutralization work can be performed without generating ozone. 2, size reduction and cost reduction can be achieved.

[Brief explanation of drawings]

Figures 1 to 3 are diagrams showing one embodiment of the present invention, with Figure 1 showing the main parts, Figure 2 not showing the overall configuration, and Figure 3 showing modification of the transfer contact member. It is a figure which shows an example. Figures 4 to 6
The figures show a conventional electrophotographic device, FIG. 4 shows the overall configuration, FIG. 5 shows a transfer device and a static eliminator,
FIG. 6 is a diagram showing a roller type transfer device. 2... Photosensitive drum (image carrier), 30... Transfer device, ... Transfer brush (contact member for transfer), ... Static eliminator, ... Static eliminator brush (contact member for weight removal).

Claims (1)

[Claims] (1) Electrophotography equipped with a transfer device that transfers a toner image formed on an image carrier onto a transfer material, and a static eliminator that is disposed downstream from the transfer device in the transfer material conveyance direction and removes static electricity from the transfer material. In the apparatus, the transfer device includes a transfer contact member capable of frictionally engaging with the back surface of the transfer material and frictionally charging the back surface upstream of the image carrier in the transfer material conveying direction, and At least a portion that comes into contact with the transfer material is formed to have the same polarity as the charging polarity of the toner image on the frictional charging series between the transfer material and the static eliminator, A charge-eliminating contact member capable of frictionally charging the back surface of the transfer material by frictionally engaging with the back surface of the transfer material at a position a predetermined distance downstream in the transfer material conveyance direction from the transfer site; An electrophotographic apparatus, characterized in that a portion that comes into contact with a transfer material is formed to have a polarity opposite to the charging polarity of the toner image on a frictional charging series between the portion and the transfer material.