JP2002182490A - Transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer device by which a dielectric belt is sufficiently destaticized and also developer stuck to the surface of the dielectric belt is surely removed without providing an exclusive cleaning blade and an exclusive cleaning roller directly used for the dielectric belt for the cleaning of the dielectric belt. SOLUTION: In this transfer device, a static eliminating roller (11) to eliminate static electricity the dielectric belt (10) is arranged at the dielectric belt (10) laid by several supporting rollers (8 and 9) so as to press one of the supporting rollers (9) via the dielectric belt (10), and also a cleaning roller (12) is provided so as to abut on the outer peripheral surface of the static eliminating roller (11), and also a cleaning blade (13) to scrape off the developer stuck to the cleaning roller (12) is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer apparatus using a dielectric belt for conveying a sheet material in a transfer area, and more particularly to a cleaning means for removing foreign matters such as a developer adhered on the dielectric belt. And a transfer device having the same.

[0002]

2. Description of the Related Art Conventionally, in many image forming apparatuses such as copying machines and printers utilizing electrophotography, a developer image formed on an image carrier such as a photoreceptor is applied with an appropriate transfer bias in a transfer area. And transferring to a sheet material. As one mode of such a process, a sheet material is electrostatically attracted onto a charged dielectric belt, and the sheet material is conveyed to a transfer area T where the surface of the image carrier and the sheet material are in contact with each other. 2. Related Art A transfer device that transfers a formed developer image onto a sheet material is known.

As one of such transfer devices, for example, as shown in FIG. 2, a dielectric belt 10 is stretched by a pair of support rollers 8 and 9 and moves at the same surface speed as the peripheral speed of the image carrier 1. And the back surface thereof is charged to a specific polarity by the bias roller 15, so that the sheet material can be electrostatically attracted. The surface of the dielectric belt 10
The specific polarity, that is, the image bearing, is determined by the voltage applied by the charging roller 14 which is disposed on the back side of the dielectric belt 10 in the transfer region T where the sheet material contacts the image carrier 1 and is provided so as to contact the back surface of the belt. The developer is charged to a polarity opposite to the polarity of the developer on the body 1. As a result, the surface of the dielectric belt 10 is charged by the charging roller 14 due to the dielectric polarization in the dielectric belt.
, That is, a polarization having a polarity opposite to the polarity of the developer on the image carrier 1.

[0004] The surface of the sheet material conveyed by the dielectric belt 10 is also polarized in the transfer region T to a polarity opposite to the charged polarity of the developer. Due to this polarization, the developer image formed on the surface of the image carrier 10 is transferred onto the sheet material. Then, the sheet material on which the developer image has been transferred is conveyed while being electrostatically held on the dielectric belt 10, and separated from the dielectric belt 10 by the strength of the sheet material at the curvature portion of the support roller 8, The sheet is transported to a fixing device (not shown).

In such a transfer device, it is necessary to provide a device for removing electricity from the dielectric belt 10 and a device for cleaning the dielectric belt 10. That is, the dielectric belt 10 is charged even after the sheet material is separated. Therefore, the charge of the dielectric belt 10 is erased, that is, the charge is removed, so that the same transfer conditions are obtained in the next sheet material transfer step. There is a need. If the charge elimination of the dielectric belt 10 is insufficient, the transfer conditions are changed due to the accumulation of electric charges, and a stable transfer image cannot be obtained. For this reason, it is preferable that the conductive static elimination roller 1 be grounded.
1 is arranged so as to be pressed against a support roller 9 which is preferably grounded via a dielectric belt 10, and the charge is removed from both sides of the dielectric belt to prepare for transfer of the next sheet material.

On the other hand, with respect to cleaning, in a transfer apparatus using the above-described dielectric belt, when images are continuously formed on a plurality of sheets, the sheets are spaced at a predetermined interval. Is being transported. In addition, when the apparatus is idling, the image carrier 1 and the dielectric belt 10 may be idled without the interposition of the sheet material, and the surface of the dielectric belt 10 may directly contact the surface of the image carrier 1. In such a case, the developer remaining on the surface of the image carrier 1 adheres to the dielectric belt 10,
Alternatively, the developer flowing in the apparatus is the dielectric belt 1
It is adsorbed on the surface of zero.

[0007] The developer adhered to the dielectric belt 10 causes back contamination of the sheet material, lowers the transfer efficiency due to uneven charging and uneven discharging, and causes uneven transfer. Therefore, in order to remove the developer adhered to the dielectric belt 10, a cleaning blade 13 is conventionally provided so as to be in contact with the dielectric belt 10, and the developer is removed.

[0008]

However, in the case where the cleaning blade 13 is used in contact with the dielectric belt 10, the frictional heat generated between the cleaning blade 13 and the moving dielectric belt 10 causes the dielectric material to move. There is a problem that the developer is fused to the belt 10 and causes the above-mentioned transfer unevenness. Further, since the developer is electrostatically attached to the dielectric belt 10, it is insufficient to physically scrape the developer by the contact of the cleaning blade 13.

Furthermore, instead of the cleaning blade 13, a cleaning roller (not shown) that is driven by the movement of the dielectric belt 10 may be provided so as to sufficiently contact the dielectric belt 10, but the cleaning roller may be provided. In order to sufficiently contact the dielectric belt 10, the cleaning effect cannot be enhanced unless the cleaning roller is made of an elastic or flexible material. In this case, the developer on the dielectric belt 10 adheres to the cleaning roller, and the developer can be removed from the dielectric belt 10.

Next, it is necessary to remove the developer adhering to the cleaning roller. However, removing the developer adhering to the surface of the elastic (or flexible) cleaning roller by contact of the cleaning blade means that the cleaning roller is elastic. However, it is difficult to do. Alternatively, the generation of frictional heat causes fusion of the developer to the cleaning blade 13 and / or the cleaning roller.

Further, when the cleaning roller is made of a rigid material such as metal, a sufficient contact width and closeness cannot be formed with respect to the dielectric belt 10, so that the contact with the dielectric belt 10 is not uniform. As a result, the removal of the developer from the dielectric belt 10 becomes insufficient, which causes back contamination of the sheet material and uneven transfer.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problem, and is a cleaning blade exclusively used for a dielectric belt for cleaning the dielectric belt while sufficiently removing static electricity from the dielectric belt. It is an object of the present invention to provide a transfer device capable of reliably removing a developer adhered to the surface of a dielectric belt without providing a cleaning roller.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a static elimination roller for eliminating static electricity from a dielectric belt stretched by a plurality of support rollers, and the dielectric belt to the static electricity. The cleaning roller is disposed so as to press one of the support rollers through the cleaning roller, and further provided with a cleaning roller so as to be in contact with the outer peripheral surface of the charge removing roller, and a cleaning blade for scraping the developer adhered to the cleaning roller. It is characterized by having been provided.

Further, the charge eliminating roller is an elastic roller, and the charge eliminating roller has a volume resistance of 10 ^4.
Characterized in that it is a to 10 ⁸ [Omega] cm.

Further, the dielectric belt has a volume resistance of 10
⁹ Ωcm or more, preferably 10 ¹⁰ to 10 ¹⁶
Ωcm, the cleaning roller is a rigid body, a conductive Teflon resin is provided on the surface of the cleaning roller, and the cleaning roller has the dielectric belt. A voltage having a polarity opposite to the polarity of the charged developer of the developer is applied.

Further, a grounded elastic neutralizing roller for neutralizing the dielectric belt stretched by a plurality of supporting rollers is provided to the dielectric belt, and the dielectric belt is grounded to one of the grounded supporting rollers. Cleaning roller, which is disposed so as to be pressed through the cleaning roller, and is further applied with a voltage having a polarity opposite to that of the developer charged on the dielectric belt, which is rigid so as to contact the outer peripheral surface of the charge removing roller. And a cleaning blade for scraping the developer adhered to the cleaning roller so as to contact the outer peripheral surface of the cleaning roller, wherein one of the support rollers, the charge removing roller, The center of each of the cleaning rollers is arranged substantially on a straight line.

With this configuration, the dielectric belt is neutralized by contacting the grounded supporting roller and the grounded neutralizing roller from both the front and back surfaces of the dielectric belt, and the developing belt adhered to the dielectric belt. The agent adheres to the peripheral surface of the charge eliminating roller due to a potential difference between the developer and the charge eliminating roller. The elastic static elimination roller forms a sufficient contact width and degree of contact with the dielectric belt, so that stable static elimination is performed, and the developer attached to the dielectric belt is also almost transferred to the peripheral surface of the static elimination roller. .

The developer adhering to the charge eliminating roller further adheres to the peripheral surface of the rigid cleaning roller in contact with the charge eliminating roller. That is, since the cleaning roller is applied with a voltage having a polarity opposite to the charging polarity of the developer, the developer on the discharging roller is charged on the peripheral surface of the cleaning roller by a potential difference between the grounding discharging roller and the cleaning roller. Adheres to Next, the developer adhered to the cleaning roller is scraped off by the cleaning blade in contact with the cleaning roller.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a transfer device according to the present invention. The parts having the same functions shown in FIG. 2 are described by the same reference numerals. In the figure, reference numeral 1 denotes an image carrier having an electrophotographic photosensitive member or the like on its surface, and has, for example, a drum shape. The image carrier 1 rotates in the direction of arrow A, and a corona charger 2 that uniformly charges the image carrier around the image carrier 1, the image carrier 1
An exposure device 3 for forming an electrostatic latent image on the surface; a developing device 4 for developing the electrostatic latent image formed on the surface of the image carrier 1 with a developer to visualize it as a developer image; Transfer device 5 for transferring a developer image formed on a body to a sheet material, image carrier 1
A cleaner 6 that removes the developer remaining on the body and an eraser lamp 7 that removes the charge remaining on the surface of the image carrier 1 are arranged so as to sequentially act to form a known image.

The transfer device 5 includes support rollers 8 and 9 spaced from each other with the transfer region T interposed therebetween, a dielectric belt 10 stretched between the support rollers 8 and 9, and a supporter via the dielectric belt 10. The charging roller 11 is disposed so as to press the roller 9, the cleaning roller 12 is in contact with the outer peripheral surface of the discharging roller 11, the cleaning blade 13 for scraping the developer adhered to the cleaning roller 12, and the dielectric belt 10 is charged. And a charging roller 14 to be used.

Each of the supporting rollers 8 and 9 has a diameter of 20 m.
m and a conductive roller made of metal or the like having a diameter of 30 mm. One of the supporting rollers 8 or 9 rotates by receiving a drive from a driving source (not shown), and the other supporting roller 9 or the supporting roller 8 is driven. Cooperates with the dielectric belt 10
Is moved in the direction of arrow B so that the surface speed becomes the same as the rotation speed of the image carrier 1. In the embodiment, the supporting roller to be driven is 8 and the supporting roller to be driven is 9, but is not limited to this. The support roller 9 is grounded through its shaft 16, and the grounding roller 1 is similarly grounded.
1, the static electricity of the dielectric belt 10 is eliminated. The support roller 8 located on the downstream side in the conveying direction of the sheet material has a small diameter for separating the sheet material on the dielectric belt 10, and the small curvature and the strain of the sheet material facilitate the separation of the sheet material. ing.

The dielectric belt 10 is provided so as to have a tension that does not bend so that the sheet material is conveyed by the support rollers 8 and 9. Further, the thickness of the dielectric belt 10 is preferably 0.05 to 0.2 mm, and in the embodiment, it is 0.1 mm, which is wider than the width of the maximum size sheet material. The volume resistance of the dielectric belt 10 is 10 ⁹ Ωcm or more, preferably 10 ⁹ Ωcm.
¹⁰ to 10 ¹⁶ Ωcm. If the resistance value of the dielectric belt 10 is low, the dielectric polarization is not sufficient, and the dielectric belt 10
Is insufficiently charged, resulting in poor transfer.

The static elimination roller 11 is provided so as to press the support roller 9 via the dielectric belt 10 and is grounded through a shaft 17. The charge removing roller 11 is preferably an elastic roller, and is 0.5 to 3 with respect to the dielectric belt 10.
By forming a conductive or semiconductive contact width (nip width) of 1 mm, uniform and sufficient static elimination can be performed. The volume resistance value of the charge removing roller 11 is 10 ⁴ to 10.
^When the resistance of the discharging roller 11 is higher than 10 ⁸ Ωcm, the discharging efficiency is reduced. When the resistance of the discharging roller 11 is lower than 10 ⁴ Ωcm, the applied voltage from the cleaning roller 12 described later is used. And abnormal discharge easily occurs in the dielectric belt 10.

The cleaning roller 12 is preferably a conductive rigid body made of metal or the like, and presses the elastic charge removing roller 11. As a result, a sufficient nip width can be formed on the charge removing roller 11, and the applied voltage having the opposite polarity to the charging polarity of the developer is applied to the charge removing roller 11 electrostatically by applying the voltage through the shaft 18. The developer can be moved to the cleaning roller 12. Further, the fact that the cleaning roller 12 is a rigid body means that pressing against the charge removing roller 11 requires only a small force, the generation of frictional heat is suppressed, and the developer on the charge removing roller 11 is efficiently transferred without fusing. Can be. In particular, by smoothing the surface of the cleaning roller 12, the developer can be easily scraped off by a cleaning blade described later.
Further, by applying a resin such as conductive Teflon resin (fluororesin) to the surface of the cleaning roller to reduce the frictional resistance, the frictional force between the cleaning blade and the cleaning roller is reduced, so that no load is applied. For example, chattering or entanglement of the cleaning blade with the cleaning roller is eliminated.

In the embodiment, the discharging roller 11 is driven by the movement of the dielectric belt 10, and the cleaning roller 12 is
It rotates following the rotation of the charge removing roller 11. Furthermore,
As shown in FIG. 1, the support roller 9 and the neutralizing roller 11
And the center of each of the cleaning rollers 12 is preferably arranged substantially on a straight line. By arranging each roller on a straight line, it is easy to adjust the pressing force on each roller.

The operation of the transfer device having such a configuration will be described. At such a timing that the developer image formed on the image carrier in the transfer area coincides with the position of the sheet material,
Sheet materials are conveyed one by one from a paper supply unit (not shown). For example, the sheet material and the dielectric belt 10 are charged by a voltage applied through a shaft 20 of a bias roller 15 disposed so as to press the support roller 9 via the dielectric belt 10, and the sheet material is attracted to the dielectric belt 10. And transport. In the embodiment, a negative voltage is applied.

The sheet material that has reached the transfer area T is charged by the charging roller 1
4 is charged. The charging roller 14 applies a voltage of a polarity (negatively charged in the embodiment) of the developer.
Due to the dielectric polarization, the sheet material is induced to have a polarity opposite to the charging polarity of the developer. As a result, the developer carried on the image carrier 1 in the transfer area T is transferred onto the sheet material. The sheet material on which the developer has been transferred is further conveyed, separated from the dielectric belt 10 by the strength of the sheet material at the position of the support roller 8 at the curvature portion of the support roller 8, and conveyed to a fixing device (not shown). After the developer on the sheet material is fixed as a permanent image, the developer is discharged outside the apparatus.

On the other hand, the dielectric belt 10 after the sheet material is separated is charged, and when passing between the grounded support roller 9 and the grounded neutralizing roller 11, both sides of the dielectric belt 10 are almost simultaneously. Static electricity is removed. Dielectric belt 10
The developer adhered when the dielectric belt 10 comes into contact with the image carrier 1 remains on the upper portion. The remaining developer adheres to the surface of the charge removing roller 11 due to a potential difference between the grounded charge removing roller 11 and the charged developer. The developer adhered to the charge eliminating roller 11 further adheres to the cleaning roller 12 due to a potential difference caused by a voltage applied to the cleaning roller 12 pressing the charge eliminating roller 11. The developer adhering to the cleaning roller 12 is scraped off by the cleaning blade 13 in contact with the cleaning roller 12, and is removed. In the embodiment, the support roller 9 and the neutralizing roller 11 are grounded, but a bias for canceling the charging of the dielectric belt 10 may be applied. Further, in the embodiment, the configuration in which the static elimination roller 11 and the cleaning roller 12 are provided on the support roller 9 via the dielectric belt 10 has been described, but the static elimination roller 11 and the cleaning roller are provided at the position of the support roller 8. A configuration may be used.

[0029]

According to the present invention, static electricity can be removed from the dielectric belt without using a cleaning blade or a cleaning roller dedicated to cleaning that comes into contact with the dielectric belt, and the developer attached to the surface of the dielectric belt can be removed by the charge eliminating roller. .

In order to remove the developer from the dielectric belt by a potential difference and adhere to the discharging roller, and from the potential removing roller to the cleaning roller and remove the developer from the rigid cleaning roller by a cleaning blade. The physical load on the dielectric belt and the charge eliminating roller is minimized, and the life of the dielectric belt and the charge eliminating roller is extended. Further, by applying a conductive Teflon resin to the surface of the cleaning roller, the physical load is further reduced.

Since the cleaning roller is rigid,
The cleaning blade is reliably brought into contact with the cleaning roller with a small force, and the generation of frictional heat between the cleaning roller and the cleaning blade is small, and the fusion of the developer to the cleaning roller and the cleaning blade is minimized.

By arranging the centers of the support roller, the charge eliminating roller, and the cleaning roller substantially on a straight line, the pressing force applied to each roller can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a transfer device according to the present invention.

FIG. 2 is a schematic view showing a conventional transfer device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Cleaner 7 Eraser lamp 8 Support roller 9 Support roller 10 Dielectric belt 11 Static elimination roller 12 Cleaning roller 13 Cleaner blade 14 Charging roller 15 Bias roller 16 Shaft 17 Shaft 18 axes 19 axes 20 axes

Claims (10)

[Claims] A static electricity removing roller for removing electricity from a dielectric belt stretched by a plurality of supporting rollers is arranged so as to press one of the supporting rollers via the dielectric belt. A transfer roller provided with a cleaning roller so as to be in contact with an outer peripheral surface of the charge removing roller, and a cleaning blade for scraping off a developer adhered to the cleaning roller; 2. The transfer device according to claim 1, wherein the charge removing roller is an elastic roller. 3. A volume resistance value of the charge eliminating roller is 10 ⁴ or more.
3. The method according to claim 1, wherein said resistance is 10 ⁸ Ωcm.
The transfer device according to any one of the above. 4. The dielectric belt has a volume resistance of 10 ⁹ Ω.
cm or more, preferably 10 ¹⁰ to 10 ¹⁶ Ωc
4. The transfer device according to claim 1, wherein m is m. 5. The transfer device according to claim 1, wherein the cleaning roller is a rigid body. 6. The transfer device according to claim 5, wherein a conductive Teflon (registered trademark) resin is provided on a surface of the cleaning roller. 7. The transfer device according to claim 1, wherein a voltage having a polarity opposite to a charge polarity of a developer attached to the dielectric belt is applied to the cleaning roller. . 8. An elastic static elimination roller for eliminating static electricity from a dielectric belt stretched by a plurality of support rollers against one of the support rollers via the dielectric belt. And a cleaning roller to which a voltage having a polarity opposite to that of the developer charged on the dielectric belt, which is rigid so as to contact the outer peripheral surface of the charge removing roller, is provided. A transfer device comprising a cleaning blade for scraping off a developer attached to a cleaning roller so as to contact an outer peripheral surface of the cleaning roller. 9. The transfer device according to claim 8, wherein the support roller and the charge removing roller are each grounded. 10. The apparatus according to claim 8, wherein the centers of one of said support rollers, said charge eliminating roller, and said cleaning roller are arranged substantially on a straight line.
Or the transfer device according to 9.