JP2002049246A - Transfer-carrying belt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer carrying belt device, capable of avoiding damage to a transfer belt caused due to insufficient durability and forming a stable high-quality image over a long time, without causing defects in image forming, and to improve the stability of the device further by stopping the device by catching information on failure to cause damages to the transfer carrying belt in advance, if the sign of such failure is shown. SOLUTION: In this transfer carrying belt device, by which the transfer material is carried and fed and a toner image is transferred to the transfer material in a transfer area, at least one of a driving roller, a driven roller and a support member, over which the transfer carrying belt used for the device is stretched and laid is formed as a drum-type roller, whose outside diameter is made larger at the center part than at both ends and which is provided with a maximum uniform outside diameter area at the center part. The width of the maximum uniform outside diameter area is made larger than the maximum effective image width of the transfer carrying belt but smaller than the width of the transfer carrying belt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, which is capable of preventing image formation failure due to damage of a transfer belt due to insufficient durability during transfer image formation and preventing the transfer conveyance belt from being damaged. The present invention relates to the provision of a transfer / conveying belt device capable of performing a stable operation for a long time by preventing it beforehand.

[0002]

2. Description of the Related Art A transfer and transfer belt transfers a toner image formed on a photoreceptor onto a transfer material while transferring a transfer material such as transfer paper on a seamless endless belt and conveying the transfer material at the same speed as the belt. An image is obtained, and the uniformity of image quality when transferring the entire surface of the transfer material from the front end portion to the rear end portion in the transport direction of the transfer material is excellent, but the belt deviation control mechanism of the transfer transport belt is relatively simple. Many transfer conveyance belts using an elastic material as a base material, which can be manufactured at low cost, have a surface coat layer having a low friction coefficient on a transfer material carrying surface for protection and improvement of cleaning properties. However, it is not so strong in terms of strength, and the base material and the surface of the belt are easily deteriorated by mechanical stress such as prevention of slippage in the conveyance direction of the belt and deviation control in a direction perpendicular thereto, and there is a problem of insufficient durability. Further, the transferred image in a part where the coat layer is easily damaged may be accompanied by an image defect.

In addition, there is a problem that the transfer material cannot be separated from the belt when the transfer material is conveyed, so that the transfer material is entangled in the cleaning portion of the belt, and the belt cleaning blade is turned up. In this case, if these problems are left unattended, the surface of the belt is damaged, transfer failure or image contamination occurs, and the belt must be replaced.

[0004]

SUMMARY OF THE INVENTION The present invention eliminates such problems, and a structure in which mechanical stress is less likely to be applied so as to always obtain a stable transfer image, or a transfer material is likely to be caught in a cleaning blade or the like. It is an object of the present invention to provide a transfer / conveyance belt device having a structure capable of detecting such a condition beforehand and stopping the device.

[0005]

This object is achieved by any of the following technical means (1) to (3).

(1) In 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 driving roller and a driven roller on which a transfer / transport belt used for the device is stretched And at least one of the support members
One is a drum-shaped roller in which the outer diameter at the center is larger than both ends and a maximum uniform outer diameter area is provided at the center, and the width of the maximum uniform outer diameter area is the maximum effective image of the transfer conveyance belt. A transfer conveyance belt device characterized in that the width is larger than the width and smaller than the width of the transfer conveyance belt.

(2) In a transfer / transport belt device for carrying / transferring a transfer material and transferring a toner image onto the transfer material in a transfer area, a traveling speed detecting means for detecting a traveling state of the transfer / transport belt used in the device is provided. Control means for stopping image formation immediately when the traveling speed of the transfer / conveying belt falls below a specified value and stopping the traveling of the transfer / conveying belt; And a display output means for displaying a transfer belt drive abnormality on a display section of the apparatus.

(3) The running speed detecting means is obtained by detecting a light receiving interval time of an optical sensor which receives light reflection between adjacent markers provided at equal intervals in a non-image area of the transfer / conveying belt. The transfer-conveying belt device according to item (2), wherein

The width of a maximum uniform outer diameter region provided at the center of each of a driven roller and a driving roller which stretches and supports or drives the transfer conveyance belt is larger than the maximum effective image width of the transfer conveyance belt. In addition, the meandering of the transfer conveyance belt can be automatically corrected, and the belt can be prevented from being damaged. That is, the phenomenon that a part of the belt back surface is strongly contacted and rubbed also in the width direction at a place where the meandering is lost and the outer diameter of the roller changes is avoided, and even if the strongly contacted portion may be slightly damaged. Since that portion is outside the effective image width of the transfer conveyance belt, it can be said that there is no adverse effect on the image portion.

When the transfer material is conveyed, the transfer material cannot be separated from the belt due to a change in electric resistance value of the transfer material due to an environmental change and a difference in surface smoothness depending on the type of the transfer material. Or the belt cleaning blade may be turned up. In this case, if these problems are left unattended, the surface of the belt will be damaged, transfer failure will occur, and the belt will need to be replaced. I tried to prevent it.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus to which the present invention is applied 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 conveying 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 sensor 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, 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, an 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 the 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 43a, the paper feed path 46, and the entrance guide plate 47, and the toner image on the photoconductor 21 is placed and transported on the transfer transport belt 454 of the transfer transport 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 conveying 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.

While the above description has been made of the state in which an image is formed on one side of the transfer material, the image forming apparatus 1 of the present embodiment performs reverse conveyance before discharging the transfer material P, 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, the transfer conveying belt device of the present invention will be described with reference to the front view of FIG. 2A, the plan view of FIG. 2B and the plan 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 friction coefficient on the transfer material P carrying surface of the base material. The belt 45 has a length equal to or longer than the transfer / conveying belt 454.
Roller 4 as a supporting member and a driving member for supporting
51, the driven rollers 452 and 453, the transfer bias applying roller 241, and the ground contact plate 244 were set to respective widths. Of these, the driven roller 452 has a width of the maximum uniform outer diameter area at the center, and the width is equal to or greater than the maximum image width and equal to or less than the width of the belt 454, and is outside the area. A drum-shaped roller with gradually narrowing both ends was adopted. Also,
The cleaning blade 455 of the transfer conveyance belt 454 is set to be equal to or larger than the maximum image width and equal to or smaller than the width of the transfer conveyance belt 454.

The transfer / conveying belt 454 is stretched on the supporting member and the driving member in a state where the transfer / conveying belt 454 extends about 4% of the natural length in the longitudinal direction of the belt, so that slip between the supporting member and the supporting member is avoided. The belt can be stably and accurately conveyed, and the belt and its coated surface can be maintained in a good state without impairing the durability.

The transfer section includes a transfer bias applying roller 241 installed inside the belt and a high-voltage bias power supply 242.
, And supplies a transfer current controlled by a constant current having a polarity opposite to that of the toner to the transfer conveyance belt 454.

The cleaning blade 455 for belt cleaning is a urethane rubber blade in contact with a counter system.

In this way, an A4 size paper passing running test was performed in a general environment.

In the durability evaluation, an A4 full size full-size halftone image and a full-color solid black image were drawn, and the image quality was determined by the presence or absence of image quality defects caused by cracks on the surface of the transfer belt.

That is, under the above-described conditions of the present invention, when the width of the maximum uniform outer diameter area of the driven roller 452 is equal to or larger than the effective maximum image width of the transfer / transport belt 454 and equal to or smaller than the width of the belt 454, 250,000. There was no image quality failure even after copying.

However, in the state where the maximum uniform outer diameter region width of the one driven roller 452 among the support members was set to be equal to or less than the effective image width of the transfer conveyance belt 454, there was no deviation of the belt, but 100,000. After the copying, a crack-like image defect occurred at the end of the belt contacting the support member.

In the loop for returning from the position of the cleaning blade 455 of the transfer / conveyor belt device 45 to the position of the cleaning blade 455 via the transfer position Bo and returning to the position of the cleaning blade 455, a semiconductor optical sensor is provided between the position of the cleaning blade 455 and the transfer position Bo. 457 is installed and the sensor 45 is installed.
7, light reflection members 458 are attached as marks at regular intervals on a surface close to the edge of the transfer and conveyance belt 454 and outside the maximum image forming area.

The time interval of the reflected light output from the optical sensor 457 is measured as shown in the graph of FIG. 4 and is compared with a reference value to calculate the speed of the transfer / transport belt 454, which is delayed more than 5% of the reference time. In this case, the image formation and the belt driving are stopped.

Then, as shown in the flowchart of FIG. 5, the drive of the transfer / conveyance belt device is started in ST1, and
In ST2, the speed of the transfer conveyance belt is detected, and the difference between the detection value detected in ST2 and the reference value or the delay time due to the speed difference is compared by the comparator in ST3.
%, The image formation and the transfer are continued as it is in ST4, and if it exceeds 5%, the driving of the image formation is stopped in ST5 and displayed on the display unit.
After removing and correcting the M and the like, the operation is returned to the driving start of ST1 and the flow is repeated.

In the above-described manner, the transfer / transport belt 45 of the transfer material
4 and the occurrence of the turning of the cleaning blade 455 of the belt can be detected in advance, the emergency stop can be performed, the necessary measures can be completed, and the operation can be continued in good order.

[0034]

According to the present invention, when forming a transferred image in an electrophotographic image forming apparatus, damage to the transfer belt due to insufficient durability can be avoided, and a high-quality image which is stable for a long time without causing image forming defects. It can be formed. In addition, if a sign of a problem that may cause damage or the like of the transfer conveyance belt appears, it can be caught in advance, and the stability of the transfer conveyance belt device is further improved.

[Brief description of the drawings]

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

FIG. 2A is a front view of a transfer and conveyance belt device of the present invention, and FIG. 2B is a plan view of the transfer and conveyance belt.

FIG. 3 is a plan view of the transfer and conveyance belt device of the present invention.

FIG. 4 is a graph schematically showing a detection result of a change in the transport speed of the transfer transport belt of the transfer transport belt device of the present invention.

FIG. 5 is a flowchart illustrating a processing method based on speed detection of the transfer and conveyance belt device 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 High voltage bias power supply 244 Ground contact plate 451 Driving roller 452, 453 Driving roller 454 Transfer / transport belt 455 Cleaning blade

Claims (3)

[Claims] 1. A transfer and transport belt device for carrying and transferring a transfer material and transferring a toner image to the transfer material in a transfer area, wherein a driving roller, a driven roller, and a transfer roller on which a transfer and transfer belt used for the device are stretched. At least one of the support members is a drum-shaped roller having an outer diameter at a central portion larger than both end portions and a maximum uniform outer diameter region provided at a central portion, and the width of the maximum uniform outer diameter region is defined as the transfer conveyance. A transfer / conveying belt device, wherein the width is larger than the maximum effective image width of the belt and smaller than the width of the transfer / conveying belt. 2. A transfer belt device for carrying and transferring a transfer material and transferring a toner image to the transfer material in a transfer area, wherein a running speed detecting means for detecting a running state of the transfer transfer belt used in the transfer device is provided. Control means for immediately stopping image formation and stopping travel of the transfer conveyance belt when the traveling speed of the transfer conveyance belt falls below a specified value; and an image forming apparatus to which the transfer conveyance belt device is attached. And a display output means for displaying an abnormality in the drive of the transfer conveyance belt on a display section of the transfer conveyance belt device. 3. The apparatus according to claim 1, wherein the traveling speed detecting means is obtained by detecting a light receiving interval time of an optical sensor receiving light reflection from adjacent markers adjacent to the markers provided at equal intervals in a non-image area of the transfer / conveying belt. The transfer conveyance belt device according to claim 2, wherein: