JP2002116628A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming device preventing a defect in image formation caused by damage due to the insufficient durability of a transfer belt by improving a cleaning means for a transfer feeding belt, and capable of forming a stable high-quality image for a long time by preventing the transfer feeding belt from being damaged in advance. SOLUTION: This image forming device has a transfer feeding belt device carrying and feeding transfer material and transferring a toner image to the transfer material in a transfer area. In order to improve the durability of the transfer feeding belt constituting the transfer feeding belt device and stabilize cleaning ability, a stirring member easily peeling adhesive toner on the transfer feeding belt is provided at the downstream position in a feeding direction of the transfer nip position of the transfer feeding belt. Furthermore, a removing member for removing the adhesive toner is provided on the downstream position of the stirring member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved image forming apparatus for an electrophotographic image forming apparatus, in which an image forming apparatus does not cause an image forming defect due to damage due to insufficient durability of the transfer belt. The present invention also relates to an image forming apparatus that can stably produce high-quality images for a long time by preventing damage to a transfer conveyance belt.

[0002]

2. Description of the Related Art A transfer / transport belt device has excellent image uniformity when an image is transferred onto the entire surface of a transfer material, for example, a transfer sheet. There is a problem of insufficient durability that the belt surface is deteriorated by mechanical stress of a cleaning blade or the like for cleaning. On the other hand, in the case of the electrostatic cleaning method which is excellent in mechanical stress, the cleaning performance for removing the toner due to the development condition, the transfer condition, the toner charge amount and environment, and the change of the surface condition of the transfer belt may be unstable and insufficient. there were.

Further, there has been a case where a transfer defect occurs due to adhesion of foreign matter to the inner peripheral surface of the transfer / conveying belt or transfer deterioration due to promotion of belt surface deterioration. In addition, when the transfer material is separated from the transfer / conveyance belt, if discharge is insufficient, peeling discharge occurs to cause image defects in some cases.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and causes image defects such as transfer failure due to transfer omission or deterioration of the transfer conveyance belt, and image defects (transfer repelling) due to peeling discharge during transfer separation. It is an object of the present invention to provide an image forming apparatus capable of obtaining stable and high-quality images.

[0005]

This object is achieved by any of the following technical means (1) to (8).

(1) In an image forming apparatus having a transfer / transport belt device for carrying / transferring a transfer material and transferring a toner image to the transfer material in a transfer area, transfer of a transfer / transport belt constituting the transfer / transport belt device is performed. An image forming apparatus comprising: a disturbing member for disturbing the toner adhered on the transfer / conveying belt at a position downstream of the nip position in the conveying direction; and a removing member for removing the adhered toner at a downstream position.

(2) The image forming apparatus according to (1), wherein the disturbance member for the adhered toner is constituted by a brush.

(3) The removing member is a conductive roller made of metal, resin, or an elastic material, and a bias power supply for applying a bias of a polarity opposite to that of the toner is provided to the conductive roller. The image forming apparatus according to (1) or (2).

(4) In an image forming apparatus having a transfer / transport belt device for carrying / transferring a transfer material and transferring a toner image to the transfer material in a transfer area, the transfer of the transfer / transport belt used in the transfer / transport belt device is performed. A cleaning member is provided for cleaning the inside opposite to the side supporting the material, and for neutralizing the transfer conveyance belt at a position downstream of the transfer nip position and at a position upstream of the position where the transfer material separates from the belt. An image forming apparatus characterized in that:

(5) The image forming apparatus according to (4), wherein the charge removing member is a conductive fur brush.

(6) The image forming apparatus according to (4), wherein the charge removing member is a conductive blade.

(7) The image forming apparatus according to (4), wherein the charge removing member is a conductive metal roller or a conductive resin roller.

(8) The image forming apparatus according to (4), wherein the static elimination member is a conductive elastic roller.

That is, the first aspect of the present invention is to install a toner disturbing member upstream of the belt traveling direction and a toner removing member downstream of the belt as a cleaning member for the transfer and conveyance belt so as to make contact with the surface of the transfer belt. An electric bias having a polarity opposite to that of the toner is applied.

According to a second aspect of the present invention, there is provided a member for cleaning the inside of the belt on the side opposite to the side on which the transfer material is carried, and for removing electricity from the belt at a position downstream of the transfer nip and upstream of the transfer material separating from the belt. That is, a charge removing member for removing and cleaning the inner side surface (inner peripheral surface) of the transfer belt is provided in contact therewith.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described first with reference to a schematic configuration diagram of FIG.

An image forming apparatus 1 shown in FIG. 1 is an image forming apparatus of a digital system, and includes an image reading section A, an image processing section B, an image forming section C, and a transfer material conveying section D as a transfer material conveying means. It is configured.

An automatic document feeder for automatically transporting a document is provided above the image reading section A.
The original placed on the original 1 is moved by the original transport roller 12 to the original 1.
The sheets are separated and conveyed, and the image is read at the reading position 13a. The document for which the reading of the document has been completed is discharged onto the document discharge tray 14 by the document conveying roller 12.

On the other hand, the image of the original placed on the platen glass 13 is read in a V-shape by a reading operation at a speed v of a first mirror unit 15 comprising an illumination lamp and a first mirror constituting a scanning optical system. Reading is performed by moving the second mirror unit 16 including the second mirror and the third mirror located at the speed v / 2 in the same direction.

The read image is formed on a light receiving surface of an image pickup device CCD as a line sensor through a projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (brightness signal), and then A
After performing / D conversion and performing processing such as density conversion and filter processing in the image processing unit B, the image data is temporarily stored in the memory.

In the image forming section C, a drum-shaped photosensitive member 21 serving as an image carrier and a charger 22 serving as a charging unit, a developing unit 23, and a transfer conveyor belt serving as a transfer unit are provided as image forming units. A device 45, a photosensitive member cleaning unit 26, and a PCL (precharge lamp) 27 as a light removing unit are arranged in the order of operation. Photoconductor 2
Numeral 1 is a photoconductive compound formed on a drum substrate by coating. For example, an organic photoreceptor (OPC) is preferably used, and is driven and rotated clockwise in the drawing.

After the rotating photoreceptor 21 is uniformly charged by the charger 22, image exposure based on the image signal called from the memory of the image processing unit B is performed by the exposure optical system 30 as image exposure means. Done. An exposure optical system 30 serving as an image exposure means as a writing means uses a laser diode (not shown) as a light emission light source, passes through a rotating polygon mirror 31, an fθ lens 34, and a cylindrical lens 35, and the optical path is bent by a reflection mirror 32 to perform main scanning. In this case, image exposure is performed on the photoconductor 21 at the position Ao, and a latent image is formed by rotation (sub-scan) of the photoconductor 21. In one example of the present embodiment, a character portion is exposed to form a latent image.

The latent image on the photoreceptor 21 is subjected to reversal development by the developing device 23, and a visible toner image is formed on the surface of the photoreceptor 21. In the transfer material transport section D, paper feed units 41 (A) and 41 serving as transfer material storage means in which transfer materials P of different sizes are stored below the image forming unit.
(B) and 41 (C) are provided, and a manual paper feed unit 42 for performing manual paper feed is provided on the side, and a transfer material P selected from any of them is supplied to a guide roller 43.
The transfer material P is fed along the conveyance path 40, and the transfer material P is temporarily stopped by a pair of registration rollers 44 for correcting the inclination and deviation of the fed transfer material P, and then re-fed, and The transfer material is guided by the pre-transfer roller 43 a, the paper feed path 46, and the entry guide plate 47, and the toner image on the photoconductor 21 is placed and conveyed on the transfer conveyance belt 454 of the transfer conveyance belt device 45 at the transfer position Bo. P, and then the transfer material P is separated from the photoreceptor 21 surface,
The sheet is conveyed to the fixing device 50 by the transfer conveyance belt device 45.

The fixing device 50 has a fixing roller 51 and a pressure roller 52. By passing the transfer material P between the fixing roller 51 and the pressure roller 52, the toner is heated and pressurized. Weld. The transfer material P on which the toner image has been fixed is discharged onto the discharge tray 64.

The above is a description of a state in which an image is formed on one side of the transfer material. The image forming apparatus 1 of this embodiment performs reverse conveyance before discharging the transfer material P, and An image is formed on the back side, and double-sided transfer can be performed. However, since the double-sided transfer is not directly related to the present invention, the description is omitted.

Next, an embodiment of an improvement which the image forming apparatus of the present invention tried on the transfer / conveying belt device 45 in order to avoid insufficient transfer belt durability and image defects due to the image defect in the image formation. Front view of FIG. 2 and FIG.
This will be described with reference to the front view of FIG.

The transfer / transport belt 454 of the transfer / transport belt device 45 is made of, for example, CR rubber as a base material of an elastic body, and has a surface coat layer having a low coefficient of friction on the transfer material P carrying surface of the base material. And a driving member 451, driven rollers 452 and 453 as a supporting member and a driving member for winding and supporting the transfer conveyance belt 454.
A transfer bias applying roller 241 and a ground contact plate 244 are provided.

The transfer / conveying belt 454 is stretched about a natural length of about 4% in the longitudinal direction of the belt and stretched around a supporting member and a driving member, so that slip between the belt and the supporting member is avoided. Stable and accurate conveyance can be performed, and it can be maintained in a good state relatively easily.

The transfer section includes a transfer bias applying roller 241 installed inside the belt and a high-voltage bias power supply 24.
2, and supplies and applies a transfer current controlled by a constant current having a polarity opposite to that of the toner to the transfer conveyance belt 454.

The transfer bias applying roller 241 comes into contact with the inside of the transfer / transport belt 454, and the outer surface of the transfer / transport belt 454 comes into contact with the photosensitive member 21 immediately above (FIG. 3) or at a slightly upstream position (FIG. 2). The transfer nip is formed as a transfer position for the transfer material P with the contact position as the center.

As shown in the front view of FIG. 2, as a disturbance member of the cleaning means of the transfer conveyance belt 454,
A brush 5 as a disturbing member is provided in a downstream area of the transfer position in the direction of travel of the transfer conveyance belt 454 and an upstream area of a removing member for removing toner from the surface of the transfer conveyance belt 454.
The conductive roller 521 as a removing member for removing the adhered toner is installed at a downstream position, and is brought into contact with the transfer belt 454.

Further, a bias having a polarity opposite to that of the toner (negatively charged) was applied to the conductive roller 521 by a constant current control of +40 μA by a bias power supply 522. Note that it is desirable to use an elastic conductive sponge roller for the conductive roller 521.

The brush (fur brush) 511 was rotated in reverse with respect to the transfer belt 454 at a linear velocity ratio of 1: 2.

The conductive roller 521 is connected to the transfer belt 454.
Was rotated at a linear speed ratio of 1: 1 in forward rotation.

Further, a scraper 523 made of PET is in contact with the conductive roller 521 to scrape and collect the cleaned toner, thereby maintaining the cleaning performance of the transfer conveyance belt 454. As a result, the following results were obtained. (1) Fur brush 511 upstream of conductive roller 521
Is installed, a stable toner removal performance is maintained during the 100 kC actual test, and cleaning failures such as toner slip-through occur even with respect to the surface deterioration of the transfer / transport belt 454, fluctuations in the amount of toner to be cleaned and fluctuations in the charge amount, and environmental fluctuations. There was no outbreak. (2) Fur brush 511 upstream of conductive roller 521
When no was installed, the cleaning failure occurred after 50 kC, and the trouble of the transfer material back surface dirt frequently occurred.

Therefore, it was confirmed that the durability of the transfer belt can be maintained twice or more as compared with the transfer belt cleaning system in which the brush 511 as the adhered toner disturbing member is not provided upstream.

On the other hand, the fur brush 511, the conductive roller 521, and the PET scraper 523 abutted on the fur brush 511 and the conductive roller 521 shown in FIG. Instead, a conductive elastic roller (Rubicell) as a cleaning neutralizing member is provided on the inner peripheral surface of the transfer conveyance belt 454 and downstream of the transfer nip position and upstream of a position where the transfer material is separated from the transfer conveyance belt. 531 manufactured by Toyo Polymer Co., Ltd.).
The conductive elastic roller 531 is provided with a blade for removing foreign matter and the like. Then, a cleaning blade 455 was provided in contact with a downstream area of the transfer conveyance belt 454. And the following results were obtained. (1) In the case where the conductive elastic roller 531 was installed, the frequency of occurrence of transfer nuisance due to the adhesion of foreign matter on the inner side surface (inner peripheral surface) of the transfer / conveying belt was negligible during the actual shooting test at 50 kC.

The frequency of occurrence of transfer cissing was negligible during the actual shooting test at 50 kC under the LL environment. (2) In the case where the conductive elastic roller 531 is not installed, the frequency of occurrence of transfer danger due to adhesion of foreign matter on the inner surface of the belt is 1
It was about once during the actual shooting test at 0 kC.

The frequency of occurrence of transfer repelling was about once during a 1 kC actual shooting test under the LL environment.

In the above-described embodiment, the conductive elastic roller 531 is used as the charge eliminating member.
In addition to the conductive elastic roller 531, a conductive fur brush, a conductive blade, a conductive metal roller, and a conductive resin roller can be used, and all have substantially the same effect.

As described above, the conductive elastic roller is brought into contact with the inner side surface (inner peripheral surface) of the transfer / conveyance belt 454 to eliminate the charge on the transfer / conveyance belt. When P is peeled off from the transfer conveyance belt and is conveyed to the fixing device, the phenomenon that repelling defects occur in the image due to separation discharge and damage to the material of the transfer conveyance belt are avoided, and the durability is greatly improved. Was.

Therefore, the effectiveness of the cleaning static elimination member was confirmed.

[0043]

According to the present invention, when a transfer image is formed in an electrophotographic image forming apparatus, damage to the transfer conveyance belt due to insufficient durability can be avoided, cleaning can be performed efficiently and accurately, and image formation failure occurs. Therefore, stable and high-quality image formation can be performed for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus of the present invention.

FIG. 2 is a front view showing an example of an embodiment of a transfer / conveying belt device used in the image forming apparatus of the present invention.

FIG. 3 is a front view showing another example of the embodiment of the transfer / conveying belt device used in the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 21 Photoreceptor 22 Charging device 23 Developing device 26 Cleaning means 30 Exposure optical system 45 Transfer conveyance belt device 50 Fixing device 241 Transfer bias application roller 242 Bias power supply 244 Ground contact plate 451 Drive roller 452, 453 Follower roller 454 Transfer Conveying Belt 455 Cleaning Blade 511 Brush (Fur Brush) 521 Conductive Roller 522 Bias Power Supply 523 Scraper 531 Conductive Elastic Roller

Claims (8)

[Claims] An image forming apparatus having a transfer / transport belt device for carrying / transporting a transfer material and transferring a toner image to the transfer material in a transfer area, a transfer nip of a transfer / transport belt constituting the transfer / transport belt device An image forming apparatus, comprising: a disturbing member for disturbing the toner adhered on the transfer / conveying belt at a position downstream of the position in the conveying direction; and a removing member for removing the adhered toner at a downstream position. 2. The image forming apparatus according to claim 1, wherein the disturbance member for the adhered toner is constituted by a brush. 3. The method according to claim 1, wherein the removing member is a conductive roller made of metal, resin, or an elastic material, and a bias power supply for applying a bias having a polarity opposite to that of the toner is provided to the conductive roller. Item 3. The image forming apparatus according to item 1 or 2. 4. An image forming apparatus having a transfer / transport belt device for carrying / transferring a transfer material and transferring a toner image onto the transfer material in a transfer area, wherein the transfer material of the transfer / transport belt used for the transfer / transport belt device is provided. A cleaning member that cleans the inside opposite to the side that carries the transfer material and that removes electricity from the transfer conveyance belt at a position downstream of the transfer nip position and at a position upstream of the position where the transfer material separates from the belt. An image forming apparatus comprising: 5. The image forming apparatus according to claim 4, wherein said static elimination member is a conductive fur brush. 6. The image forming apparatus according to claim 4, wherein the charge removing member is a conductive blade. 7. The image forming apparatus according to claim 4, wherein the charge removing member is a conductive metal roller or a conductive resin roller. 8. The image forming apparatus according to claim 4, wherein the static elimination member is a conductive elastic roller.