JPH04238382A - Image flow preventing metho on image forming device - Google Patents

Abstract

PURPOSE:To prevent 'flow of image' which occurs when a new toner disturber brush is used, in an image forming device provided with a cleaning means a cleaning device and a toner disturber brush arranged on the upper stream of the cleaning means. CONSTITUTION:In the image forming device having the cleaning device 30 having the cleaning means arranged close to a photosensitive body for cleaning residual toner on a mobile organic system photosensitive body, and the roll-like toner disturber brush 17 being in contact with the photosensitive body and rotated, at the position of the upper stream of the cleaning and formed by planting resin fiber, the uniform electrification of the photosensitive body, the development of an uniformly electrified part with toner, and the cleaning of the photosensitive body by the cleaning device, are carried out, after the new roll-like toner disturber brush 17 is loaded and before an image forming action is carried out, so that the developing toner of a fixed quantity or more is supplied to the toner disturber brush 17.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for preventing image fading in an image forming apparatus such as an electrophotographic copying machine, a printer, or a facsimile machine that uses toner to develop an electrostatic latent image. The present invention relates to a method for preventing image deletion in an image forming apparatus using a cleaning device equipped with a toner deturbator brush disposed in a toner deturbator brush.

0002

2. Description of the Related Art Recently, in electrophotographic copying machines, an organic photoreceptor called OPC has been used instead of an inorganic photoreceptor such as selenium. As shown in FIG. 9(a), the OPC photoreceptor has a three-layer structure in which an undercoat layer UCL, a charge generation layer CGL, and a charge transport layer CTL are sequentially provided on a conductive substrate CB, or figure(
As shown in b), a charge generation layer CG is formed on the conductive substrate CB.
Some photoreceptors have a two-layer structure in which L and charge transport layer CTL are provided in this order, and are laminated photoreceptors. Undercoat layer UCL
The charge generation layer CGL usually has a thickness of 1 μm or less, and the charge transport layer CTL has a thickness of 10 to 30 μm. Among these layers, the charge transport layer CTL, which is in direct contact with the cleaning member and the developing member, is made of an organic material and is therefore generally fragile and easily abraded. This wear may be caused by the developing system, contact with copying paper, etc., but the most common cause is the cleaning member (blade, fur brush). For this reason, a binder polymer is selected that has electrical properties such as chargeability and ozone resistance, and is also resistant to wear and scratches. In general,
Polycarbonate resin, polyester resin, methacrylic resin, etc. are used.

By the way, "filming" and "image blur" are phenomena that are often observed in image forming apparatuses that combine an OPC photoreceptor and a blade cleaner. "Filming" is a phenomenon in which components in the toner adhere to the surface of the OPC photoreceptor, gradually grow, and the area becomes no longer attenuated by light, resulting in a high potential and printout. This phenomenon is particularly common in magnetic one-component development systems, and is likely to occur when originals with the same pattern are repeatedly copied under high temperature and high humidity conditions. Furthermore, "image blur" is a phenomenon of image loss caused by electrostatic loss that occurs under high temperature and high humidity conditions. This is because: ■Paper powder such as talc, rosin, starch, etc. contained in the transfer paper adheres to the surface of the photoreceptor during the transfer process and is strongly rubbed against the photoreceptor by the cleaning blade.■This absorbs water under high humidity. Furthermore, ■ corona discharge equipment always produces a large amount of discharge products (
NOx, O3) are generated, and the water-soluble components of these dissolve into the paper dust attached to the photoreceptor surface and dissociate into ions, resulting in an extremely low electrical resistance on the photoreceptor surface and the formation of a latent image. This is a phenomenon that occurs when the three conditions (1) to (2) of creeping leakage occur, and especially occurs under high temperature and high humidity conditions. By removing any one of these conditions, "image blurring" can be prevented, but since the moisture in (2) is supplied by the paper, it is difficult to remove. Furthermore, it is also difficult to prevent the discharge products (3). Also, even if we exclude ■ and ■, ■
When talc adheres to the photoreceptor surface, "talc fog" occurs.
A so-called skin fogging occurs. In order to eliminate the condition (①) above and prevent "image blurring," the cleaning blade should either increase the hardness of the urethane rubber that makes up the blade or increase the pressure of the blade to clean the surface of the photoreceptor. It is effective to mechanically scrape off the deposits on the surface of the photoreceptor by rubbing more strongly. However, if you try to obtain this scraping effect only with a cleaning blade, you will inevitably have to use it to scrape the charge transport layer CTL more aggressively, which will worsen the scratches on the photoreceptor and cause the problems mentioned above. . Under these circumstances, as a measure to prevent "image drift" and "talc fogging" caused by talc adhesion, untransferred toner and paper dust are removed from the photoconductor upstream of the cleaning blade or disturbed on the photoconductor to strengthen the adhesion. The present applicant has already proposed a toner deturbator brush that weakens the
Utility Model No. 63-160576). By appropriately selecting the parameters of the mechanical contact state of the deturber brush to the photoreceptor, the pressure and hardness of the cleaning blade can be minimized, and the charge transport layer formed by the deturber brush itself can be minimized. It becomes possible to minimize wear of the CTL.

0004

[Problems to be Solved by the Invention] However, cleaning using a toner destabilizer brush located upstream of the cleaning blade as described above removes untransferred toner and paper dust from the photoconductor or disturbs it on the photoconductor to weaken its adhesion. For example, when the photoreceptor unit consisting of the photoreceptor drum and cleaning device is replaced with a new one, or the cleaning device is replaced with a new one and about 300 copies are made, "image deletion" and "talc fogging" may occur. ' was found to increase rapidly.

[0005] Therefore, the object of the present invention is particularly to
In image forming apparatuses such as electrophotographic copying machines, printers, facsimile machines, etc. that use a photoreceptor drum, and that use a cleaning device that is equipped with a cleaning device and a toner deturbator brush disposed upstream of the cleaning device, new An object of the present invention is to provide a method for preventing "image washing" that occurs when using a cleaning device, especially a new toner deturbator brush.

[0006]

[Means for Solving the Problems] The present invention was completed as a result of pursuing the cause of "image drift" that occurs when using a new toner deturbator brush as described above, and has achieved the above object. A first method for preventing image blur in the image forming apparatus of the present invention includes a cleaning means disposed close to the photoconductor and a cleaning device located upstream thereof, in order to clean residual toner on the moving organic photoconductor. In an image forming apparatus having a cleaning device equipped with a rolled toner deturbator brush formed by flocking resin bristles that rotate in contact with a photoconductor, at least a new rolled toner deturbator brush is loaded. After that, before performing an image forming operation by uniformly charging the photoreceptor, image exposure, developing an electrostatic latent image with toner, and transferring the developed toner image to paper, uniformly charging the photoreceptor, This method is characterized in that a uniformly charged portion is developed with toner, a photoreceptor is cleaned by the cleaning device, and a predetermined amount or more of developing toner is supplied to the toner deturbator brush.

[0007] Furthermore, the second image forming apparatus of the present invention
The method for preventing image blurring is to clean residual toner on a moving organic photoreceptor by using a cleaning means disposed close to the photoreceptor and a resin material rotating in contact with the photoreceptor at a position upstream of the cleaning means. The cleaning device is equipped with a roll-shaped toner deturbator brush formed by flocking hairs of In an image forming apparatus that uniformly charges a photoreceptor, uniformly exposes it, develops it with toner, and cleans it, uniformly charges the photoreceptor at least 300 times from the beginning after loading at least a new rolled toner deturbator brush. , during image forming operations such as image exposure, development of an electrostatic latent image with toner, and transfer of the developed toner image to paper, the toner destar is This method is characterized by supplying a predetermined amount or more of developing toner to the bar brush.

[0008] In both the first method and the second method, the effect is great when the toner is a magnetic one-component toner.

[0009]

[Operation] In the first method of the present invention, before performing an image forming operation, the photoreceptor is uniformly charged, the uniformly charged portion is developed with toner, and the photoreceptor is cleaned by the cleaning device. In the second method, the photoreceptor is uniformly charged, image exposed, and statically charged by the toner at least within 300 times from the beginning. During image forming operations such as developing an electrostatic latent image and transferring the developed toner image onto paper, at least a portion of the uniform exposure of the interimage area is stopped to apply a predetermined amount or more to the toner deturbator brush. Since developing toner is supplied, at least before "image deletion" occurs, the collected toner enters between the flocked resin bristles of the rolled toner deturbator brush and adheres to the bristles. This increases the mechanical hardness, and by preventing hairs from falling, the ability to remove talc exceeds the amount of talc deposited, so "image blur" due to talc can be prevented.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method for preventing image blur in an image forming apparatus according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the overall configuration of an example of an image forming apparatus to which the image blur prevention method of the present invention is applied. The apparatus shown in FIG. 1 is an example of a two-color copying machine. This device includes an exposure device 110 fixed to the device, an OPC photosensitive drum 3,
Photoconductor unit 1 consisting of cleaning device 30 and charging device 61, developer units 92a, 92b, transfer device unit 111, fixing device unit 112, paper tray 10
0, and each of these units is configured to be able to be pulled out independently toward the front of the device, so that each unit can be removed from the device for maintenance such as cleaning, cleaning, etc. The photoreceptor unit 1 is configured to be replaced with a new one every 100,000 copies, for example. During 100,000 copies,
The residual toner collected from the photoreceptor drum by the cleaning device of the present invention is automatically and reliably collected and stored in the photoreceptor unit, and the user does not come into contact with the residual toner collected in the photoreceptor unit. In FIG. 1, this copying machine includes mirrors 83, 84, 85, 87, 88, and 8 along with an exposure lamp 82 located below a platen 81.
When scanning the original 80 on the platen 81, the light emitted from the exposure lamp 82 and reflected on the surface of the original 80 is reflected by the mirrors 83, 8.
4, 85, lens 86, and mirrors 87, 88, 89
The photoreceptor drum 3 is guided to the exposure position via the photoreceptor drum 3. A charger 61 and a first developer 9 for red toner are installed around the photoreceptor drum 3 to execute the image forming process.
2a, a second developing device 92b for black toner, a transfer device 93, and a peeling corotron 94 are arranged, and furthermore, in the latter stage, a peeling claw 95, a toner deturbator brush 17 rotating in contact with the surface of the photosensitive drum 3, and a photosensitive drum 3. A cleaning device 30 having a cleaning blade 23 that slides on the surface of the body drum 3 is disposed. In addition, the first developing device 92a
An interimage lamp 97 is arranged in front of the photoreceptor drum 3 for optically eliminating charges in the interimage section, and a cleaning blade 23 and a charging device 61 are also arranged.
An erase lamp 113 is provided between them. Then, the paper sent out from the paper tray 100 is supplied to the transfer position (transfer device 93, peeling corotron 94 arrangement position) via the paper feed conveyance path 102, and after the toner image is transferred, the paper is sent to the fixing device 105 via the conveyance path 104. The image is then sent to and fixed. After that, the fixed paper is discharged to the conveyance path 1.
06 to the tray 108. Note that a return conveyance path 103 is provided downstream of the fixing device 105 to return the paper on which an image has been fixed once for multiple copying or backside copying to an intermediate tray (not shown), and the return conveyance path 103 A gate 107 performs sorting of sheets between the discharge transport light path 106 and the return transport light path 103.

FIG. 2 shows a cross section taken perpendicular to the rotation axis of the photosensitive drum of the photosensitive unit 1 of the copying machine shown in FIG. 1, and FIG. 3 shows a cross section taken along the line III-III' in FIG. A cross section taken about is shown. In the figure, die-cast cylindrical side plates 5 and 7 are fitted into both ends of the photoreceptor drum 3, and the space partitioned by the photoreceptor drum 3 and the side plates 5 and 7 serves as a first space for storing residual toner. It constitutes a container 4. A rotation shaft 9 is integrally provided at the center of the side plate 7 of the photoreceptor drum 3 on the back side of the apparatus, and is rotatably attached to the housing 11 of the photoreceptor unit 1 via a bearing. A circular opening is provided at the center of the front side plate 5, and is rotatably fitted into a cylindrical portion 13 protruding from the housing 11 to the inside of the unit via a bearing. Also, a gear 15 is cut on the outer periphery of the side plate 7 on the back side, and when the unit 1 is pushed into the device body from the front and set, it meshes with a drum rotation drive gear (not shown) on the device body side. ing. Note that the device body has a positioning hole (not shown) into which the tip of the rotating shaft 9 protruding outward from the housing 11 is fitted, and a shaft (not shown) into which the tip of the rotating shaft 9 fitted into the positioning hole 16 provided in the housing 11 of the unit 1 is fitted. ), which constitutes a positioning mechanism when the unit 1 is pushed into the main body of the apparatus and set.

A roll-shaped toner deturbator brush (hereinafter referred to as an auxiliary brush) 17 is rotatably attached via a bearing between the extended side walls of the housing 11 provided at both ends of the photosensitive drum 3. As shown by the arrow in the figure, this auxiliary brush 17 rotates in the same direction as the moving direction of the photoreceptor drum 3 at the contact position with respect to the photoreceptor drum 3, so that the auxiliary brush 17 remains on the drum 3 without being transferred by the transfer device. It removes toner, talc, paper powder, etc. from copy paper to prevent them from adhering to the surface of the photoreceptor, causing image blur, comets, fog, etc. in the copied image and deteriorating the image. This prevents toner from sticking to the surface of the photoconductor and causing filming that cannot be removed, and a part of the toner staying in the auxiliary brush 17 is constantly supplied to the cleaning blade 23 as a lubricant. The auxiliary brush 17 is formed into a roll by planting resin bristles, such as polypropylene, at a high density around the entire circumference of the rotating shaft 19. A gear 21 is fixed and meshes with a gear 29 for rotationally driving a toner transport rotary paddle 27, which will be described later. Furthermore, an elastic cleaning blade 23 is provided downstream of the point of contact between the photosensitive drum 3 and the auxiliary brush 17, with one side fixed to the housing 11 and the other side touching the drum 3 at an acute angle with respect to its rotating direction. The toner, talc, paper powder, etc. left behind by the auxiliary brush 17 are scraped off from the photoreceptor drum 3. Further, a scraping member 22 for scraping off toner adhering to the auxiliary brush 17 is attached to a partition wall 32 to be described later.
The tip is attached to the auxiliary brush 17. Furthermore, in order to convey the residual toner scraped off onto the bottom plate 25 of the housing 11 by the auxiliary brush 17 and the cleaning blade 23 in the direction away from the cleaning device 30, the rear side of the auxiliary brush 17 in the housing 11 (from the drum 3 A toner conveying rotary paddle 27 is rotatably provided on the far side) parallel to the toner conveying paddle 27 via a bearing. A gear 29 is fixed to the shaft rear end of the rotary paddle 27, and meshes with a gear 21 for rotating the auxiliary brush 17, so that the rotary paddle 27 and the auxiliary brush 17 rotate in the direction of the arrow shown. Incidentally, the housing 11 forms a toner collection box 31, which is a second container for storing residual toner, on the rear side of the cleaning device 30, which is composed of the auxiliary brush 17, the cleaning blade 23, and the toner conveying rotary paddle 27. Cleaning device 3
0 and the toner collection box 31 are partially separated by a partition wall 32. An elastic plate member 34 is provided with one end fixed to the partition wall 32 and extending downward, and its lower end is in elastic contact with the plane of the rotary paddle 27. The rotary paddle 27 has a regular polygonal cross section as shown in the figure, and by rotating in the direction of the arrow shown in the figure, serves to scrape out residual toner accumulated on the rear side of the auxiliary brush 17 into the toner collection box 31. . The plate-like member 34 whose tip is in elastic contact with the polygonal cross-sectional surface has the effect of scraping off the toner adhering to the surface and preventing the toner accumulated in the toner collection box 31 from returning to the cleaning device 30. It acts to prevent

A rotary shaft 33 is rotatably provided in the rear housing 11 near the bottom of the toner collection box 31, and a strip-shaped plate member is attached to the toner collection box 31 side with the normal line of the surface thereof. An elastic toner conveying auger 35 formed in a helical shape (spiral shape) so that the toner is oriented in the axial direction of the cylinder is coaxially fixed. Further, a gear 37 for rotating the auger is attached to the rear end of the rotating shaft 33 via a torque limiter mechanism 38 that disconnects when a torque exceeding a predetermined value is applied. The toner transport auger 35 extends along the bottom of the toner collection box 31 in parallel with the toner transport rotary paddle 27 and the like, and its tip is connected to the circular opening 3 provided in the front wall of the housing 11.
It has a length that protrudes through 9. The circular opening 39 and the inner hole 41 of the cylindrical portion 13 protruding from the housing 11 are connected by a pipe 43 having an inner diameter slightly larger than the cross section of the toner conveying auger 35. The toner conveying auger 35 bends along this pipe 43, and its tip 45 protrudes into the internal space 4 of the drum 3. As mentioned above, the toner conveyance auger 35 has the shape of a flexible helical spring, and when it is rotated, it conveys the toner that has entered between its blades in the axial direction using the principle of a helical pump. It is something to do. Therefore, the toner collection box 31
By rotating it within the drum 3, the residual toner at the bottom of the toner collection box 31 can be conveyed along the pipe 43 to the space 4 within the drum 3. Note that both the gear 37 for rotating the toner conveying auger 35 and the gear 29 for rotating the rotary paddle 27 are engaged with a driving gear 47 rotatably provided on the rear wall of the housing 11. , the driving gear 47 engages with a driving gear (not shown) provided on the main body when the photoreceptor unit 1 is set in the main body of the apparatus, and drives the cleaning brush 17, the toner transport rotating paddle 27, and the toner transport auger 35. Rotate. In addition to the helical spring shape as described above, the toner conveying auger 35 may be, for example, a flexible wire having a spiral plate-like protrusion around its periphery.

Inside the toner collection box 31 is a float member 49 that floats from below with the accumulated toner when the residual toner contained therein exceeds a predetermined amount.
An opaque shielding member 51 is integrally provided above the float member 49. A protrusion 53 made of a transparent wall is provided at the upper part of the housing 11 and forms a space into which the shielding member 51 enters from below when the float member 49 floats and rises. On the other hand, the main body of the apparatus is provided with a groove 55 into which the protrusion 53 enters when the photoreceptor unit 1 is set.
A light emitting element 57 and a light receiving element 59 are arranged opposite to each other on both sides of the groove 55.
is provided. Therefore, when the residual toner in the toner collection box 31 exceeds a predetermined amount, the float member 49
rises to follow the surface, and the shielding member 51
will also rise. This shielding member 51 rises within the protrusion 53 and, when it reaches a certain height, blocks the optical path that exits the light emitting element 57, passes through the protrusion 53, and reaches the light receiving element 59. Therefore, by detecting this interruption, it is possible to detect that the toner collection box 31 is full of collected residual toner. For details of this full detection mechanism 60, please refer to Utility Model Application No. 63-39259, which was previously filed by the present applicant as Utility Model Application No. 1983-132700, and is a publication thereof. It should be noted that the fullness detection mechanism 60 is not limited to the one described above, and it is obvious that various types of known types can be used.

Note that in FIG. 2, the photoreceptor unit 1
A charger 61 is integrally provided downstream of the cleaning blade 23 to uniformly charge the photosensitive drum after cleaning for forming a latent image.

The operation of the photoreceptor unit equipped with the cleaning device configured as above will be explained.

The photosensitive drum 3 uniformly charged by the charger 61 undergoes image exposure in the exposure section 110.
An electrostatic latent image is formed on the surface of the photoreceptor drum 3. Next, toner charged to a polarity opposite to that of the electrostatic latent image by the developing device 92a or 92b is brought into contact with the surface of the photoreceptor drum 3 to form a toner image. This toner image is brought into contact with a sheet of paper conveyed at a speed equal to the circumferential speed of the photosensitive drum 3 in a transfer device 111 provided at the next position, and is transferred onto this sheet of paper. The paper onto which the toner image has been transferred is conveyed to the fixing device 112, where the toner image is fixed on the paper.
Ejected from the device.

On the other hand, the photosensitive drum 3 reaches the cleaning device 30, and the toner remaining on its surface without being transferred by the transfer device 111 is scraped up from below by a rotating roll-shaped auxiliary brush 17. removed. A part of the removed toner adheres to the auxiliary brush 17 and reaches the position of the scraping member 22, and the auxiliary brush 1
7 collides with this scraping member 22, and is thrown off and scraped onto the bottom plate 25 of the housing 11. Further, a portion of the toner removed by the auxiliary brush 17 and a portion of the toner remaining within the auxiliary brush 17 are scattered toward the cleaning blade 23 and are constantly supplied as a lubricant to the cleaning blade 23 . The auxiliary brush 17 removes not only residual toner but also talc, paper powder, etc. generated from the copy paper and attached to the surface of the photoreceptor drum 3, which causes deterioration of the copied image such as image deletion, comets, and fog. act. Toner remaining on the photoreceptor drum 3 without being scraped off by the auxiliary brush 17 is scraped off by the cleaning blade 23 and similarly falls onto the bottom plate 25 of the housing 11. Note that the cleaning blade 23 is made of an elastic material such as polyurethane rubber, and is disposed in contact with the surface of the photoreceptor drum 3 at an acute angle with respect to the rotation direction of the photoreceptor drum 3 as shown in the figure. If there is no blade, the friction with the photoreceptor drum 3 will cause the blade to be rolled up in the circumferential speed direction of the photoreceptor drum 3 (in the direction of the arrow in the figure), causing chattering and causing the blade to no longer function as a cleaning means. . Therefore, as described above, the auxiliary brush 17
A configuration in which a portion of the toner removed from the toner is constantly supplied to the cleaning blade 23 as a lubricant is important, especially in a cleaning device that employs a blade-shaped cleaning means. In addition, auxiliary brush 1
It is also conceivable that the rotating direction of the photosensitive drum 7 is opposite to that shown in the figure, so that the rotation direction of the photosensitive drum 3 is made to move in opposite directions at the point of contact with the photosensitive drum 3.

Auxiliary brush 17 and cleaning blade 2
The residual toner scraped off by the cleaning device 30 and accumulated on the bottom plate 25 of the housing 11 is removed by the toner conveying rotary paddle 27 rotating at this position.
The toner is scraped out into a toner collection box 31 provided adjacent to the toner. The residual toner scraped out into the toner collection box 31 is transferred to the photoreceptor through the pipe 43 by the rotation of a toner transport auger 35 provided near the bottom of the toner collection box 31, preferably near the toner transport rotation paddle 27. It is conveyed to the space 4 within the drum 3. Note that even within the pipe 43, the toner conveying auger 35 can rotate around the axis while being bent due to its elasticity to convey the residual toner in the axial direction. During this time, the residual toner scraped into the toner collection box 31 is sequentially transported to the space 4 within the photosensitive drum 3 by the toner transport auger 35, so that the residual toner does not accumulate within the toner collection box 31. When the space 4 inside the photoreceptor drum 3 is filled with residual toner, a large resistance begins to be applied to the toner transport auger 35. When this resistance exceeds a predetermined level, the torque limiter mechanism 38 provided between the rotating shaft 33 of the toner transport auger 35 and the auger rotation gear 37 acts, and the toner transport auger 35 rotates. The residual toner is no longer conveyed to the space 4 within the photoreceptor drum 3, and the conveyance of the residual toner to the space 4 within the photoreceptor drum 3 is stopped. Therefore, the toner transport rotating paddle 27
The residual toner scraped out by the toner begins to accumulate in the toner collection box 31. When the residual toner contained therein reaches a predetermined amount or more, the float member 49 rises to follow the surface thereof, and the shielding member 51 also rises together. When the shielding member 51 rises inside the protrusion 53 and reaches a certain height, it blocks the optical path that exits the light emitting element 57, passes through the protrusion 53, and reaches the light receiving element 59. It is possible to detect that the collection box 31 is full of collected residual toner. The copying device may be stopped by this signal, but at the position where the shielding member 51 first blocks the optical path from the light emitting element 57 to the light receiving element 59, a predetermined amount of residual toner is further stored in the toner collection box 31. This signal is used as a warning signal to warn that the space 4 inside the photosensitive drum 3 and the toner collection box 31 will be filled with collected residual toner after a predetermined number of copies have been made. You can also use it. The photoreceptor unit 1 filled with residual toner is replaced with a new one.

By the way, when using an OPC photoreceptor and using magnetic one-component toner as the toner, the photoreceptor unit 1
We investigated the changes in ``image blur'' and ``talc fogging'' with respect to the number of copies made when the original was replaced with a new one. The results are shown in FIG. In this measurement, "image blur" and "talc fog" were evaluated using a five-level grade evaluation. The diameter of the photoreceptor drum 3 is 84 mm, and the ratio of the peripheral speed of the auxiliary brush 17 to the peripheral speed of the photoreceptor drum 3 is 1.6.
, the nip amount of the auxiliary brush 17 with respect to the photoreceptor drum 3 is 1.0 mm, and the auxiliary brush 17 has an outer diameter of 18 mm.
．． 5mm, shaft diameter 6mm, the bristles are made of polypropylene resin, 17 denier, and the density is 60,000 bristles/hair.
in2, pile height is 5.5 mm, and the cleaning blade 23 is made of thermosetting polyurethane, hardness 70°Hs, width 10 mm, thickness 2.
mm, and the contact angle θ shown in FIG. 2 was 22°. As is clear from FIG. 4, when the cleaning device 30 is renewed, the amount of talc deposited on the photoreceptor 3 increases as the number of copies increases while several hundred copies are made. When the number of copies reaches about 300, "image drift" occurs.
begins to occur, and becomes worst when the number of sheets is around 800. Thereafter, the amount of talc deposited begins to decrease, and when the number of sheets reaches about 1,500 sheets, "image deletion" hardly becomes a problem. As a result of investigating the cause of the change in the amount of talc deposited on the photoreceptor when the cleaning device is replaced, it was found that the cause was the auxiliary brush 17.

That is, as mentioned above, the auxiliary brush 17 rotates while contacting the photoreceptor drum 3, so that the auxiliary brush 17 is not transferred by the transfer device and is transferred to the drum 3.
This removes residual toner, talc, paper powder, etc. from the copy paper, and prevents them from adhering to the surface of the photoreceptor, resulting in blurred images, comets, fog, etc., and deterioration of the image. This function prevents toner from adhering to the photoreceptor surface and causing filming that cannot be removed, and also constantly supplies part of the toner staying in the auxiliary brush 17 to the cleaning blade 23 as a lubricant. It is something that does. However, when the photoreceptor unit 1 is replaced with a new one, the auxiliary brush 17 is also replaced with a new one. The collected toner has not yet entered between the flocked high-density resin bristles of the new auxiliary brush 17, and the bristles will fly off when they come into contact with the photoreceptor drum 3. , the ability of the auxiliary brush 17 to remove the above-mentioned talc etc. cannot be fully demonstrated. Therefore, while the auxiliary brush 17 is new, the amount of talc deposited on the photoreceptor 3 from the paper is the same as that of the auxiliary brush 17.
Since the amount of talc scraped off is greater than the amount of talc scraped off in step 7, as shown in FIG. When the number of sheets reaches about 300, "image blur" begins to occur. However, when a certain number of copies are made, the collected toner enters and adheres between the flocked bristles of the auxiliary brush 17, reducing the tendency of the bristles to fall down, and causing the bristles to stand up and cause mechanical hardness. The amount of talc scraped off by the auxiliary brush 17 is greater than that of the photoconductor 3 because the adhering magnetic monocomponent toner itself has high hardness and has the ability to remove talc and the like. The amount of talc deposited from the paper begins to exceed that of the paper. From Figure 4, this point is thought to be around 800 sheets. Therefore, when the number of copies exceeds this point, the amount of talc deposited begins to decrease and reaches about 1,500 copies, which is below the level where the amount of talc deposited becomes a problem, and the problem of "image blur" almost disappears. The relationship between the amount of talc deposited and the amount of talc scraped off is conceptually expressed as shown in FIG. In addition, at the beginning of replacing the auxiliary brush 17, it is possible to increase the hardness of the bristles of the auxiliary brush 17 in order to prevent "image blur" due to talc adhesion as shown in FIG. As a result, the OPC photoreceptor 3 is severely worn, and its lifespan is shortened. Therefore, this solution has limitations.

Now, in order to prevent the above-mentioned "image deletion" at the beginning of replacing the auxiliary brush 17, as is clear from the mechanism, residual toner must be actively supplied to the cleaning device 30 at the beginning of replacing the auxiliary brush 17. Just do it. Instead, it is possible to sprinkle toner on the auxiliary brush 17 in advance, but unless the toner is electrically charged, the toner will enter between the bristles of the auxiliary brush 17 and will not adhere, making it impossible to achieve the purpose. To supply residual toner to the cleaning device 30 at the beginning of replacing the auxiliary brush 17,
There are several methods that can be considered, but a simple method is when the cleaning device 30 including the auxiliary brush 17 is replaced (in the embodiments shown in FIGS. 1 to 3, when the photoreceptor unit 1 is replaced). time), before you start copying.
The entire surface of the photoreceptor drum 3 is charged without exposure, and the developing device 9
2, the toner is deposited to make it solid black, the toner is sent to the cleaning device 30, and the auxiliary brush 17 and the cleaning blade 23 collect the toner. In the example shown in FIG. 4, the amount of toner that ultimately adheres to the auxiliary brush 17 is 500 to 600 mg, and if this amount of residual toner adheres to the auxiliary brush 17, the ability to scrape off talc is sufficient. On the other hand, since approximately 100 mg of residual toner is collected when the area of one copy is made solid black, it is necessary to supply toner to the cleaning device 30 as described above for the amount equivalent to several copies before starting copying. Bye. A timing chart for each process of the copying machine shown in FIG. 1 is shown in FIG. That is, before replacing the photoreceptor unit 1 with a new one and starting copying, only the charger 61, the developer 92, and the cleaning device 30 are operated, and the exposure lamp 82, interimage lamp 97, and paper feed conveyance path 106 are operated. etc., paper feeding system, transfer device 11
1 is not operated, and a solid black image is developed on the photoreceptor drum, and this is applied to the auxiliary brush 17 of the cleaning device 30. Since the bristles of the auxiliary brush 17 are triboelectrically charged to the opposite polarity to the toner, almost no The remaining toner is removed by the auxiliary brush 17.
It is adsorbed between the hairs of the skin. If this operation is performed for a time corresponding to several copies as described above, and then normal copying is started, "image deletion" and "talc fogging" as shown in FIG. 7 will hardly occur. Note that FIG. 7 was measured under the same conditions as in FIG. 4. By the way, in the normal copying process, as shown in FIG.
1. Although only the developing device 92 and the cleaning device 30 are not operated, a self-diagnosis function provided in the copying machine may be used to perform such operations. Also,
It is also easy to provide a special mode for such selective operation.

Another method of supplying the residual toner to the cleaning device 30 at the beginning of replacing the auxiliary brush 17 is to actively supply the residual toner to the cleaning device 30 during the initial copying, instead of supplying it before the start of copying. The intermediate image area located between one image exposure and the next image exposure is made solid black and used. That is, in FIG. 1, in the interimage lamp 97, the charger 6 is originally located between the images (interimage area).
1 and is not exposed to light, the charged portion is developed into a solid black toner image by the developing device 92 and reaches the cleaning device 30 without being transferred by the transfer device 93, thereby preventing the cleaning ability of the cleaning device from being degraded. In order to do this, the interimage area is uniformly exposed to light to eliminate static electricity. However, as is clear from FIG. 4, the interimage lamp 97 is partially inactivated until the number of copies reaches 300 or less, and this section is used to remove the necessary amount of residual toner from the auxiliary brush 17. can be supplied, thereby preventing "image drift". 8th
The figure shows a timing chart of each process when the copying machine of FIG. 1 is configured in this manner. Charger 61 and exposure lamp 8 from the start of copying after replacing photoconductor unit 1
2, developing device 92, transfer device 111, cleaning device 3
The operation of 0 is the same as normal, but from the beginning there are N sheets (N≦3
00), the inter-image lamp 97 is turned off only for a time t or a shorter time Δt out of the exposure time t of each interim image portion. In this way, the developing device 92 develops a solid black toner image by a length corresponding to Δt of the interimage area, and this toner image is not transferred onto the paper by the transfer device 93 (the paper is not transferred to the interimage due to the timing). (When the part is at the transfer position, it has not reached the transfer position.), it reaches the cleaning device 30 and is attracted between the bristles of the auxiliary brush 17. The above time Δt is
500~ to the auxiliary brush 17 within the number N of 300 or less
Selected to provide 600 mg of residual toner.

[0025] Before starting copying in the former case, a charger,
Comparing the method of supplying residual toner by operating only the developing device and cleaning device, and the latter method of supplying residual toner during initial copying by using the intermediate image section, the latter method uses only the developing device and cleaning device to supply residual toner during initial copying. This method is more desirable because it does not cause a drop in density due to sudden load on the surface, and it does not cause poor cleaning.

By the way, in addition to the above-mentioned method of supplying residual toner to the auxiliary brush 17 to increase its talc scraping ability from the beginning to prevent "image deletion," there is also a method to prevent talc from adhering to the surface of the photoreceptor. As a method to
One idea is to prevent the paper onto which the toner image is transferred from coming into contact with the surface of the photoreceptor as much as possible. To achieve this, the surface of the photoreceptor is made rough rather than a mirror surface, so that the photoreceptor and the paper come into point contact, thereby reducing the contact area of the photoreceptor with the paper, and as a result, the amount of talc deposited can be reduced. Furthermore, by making the surface of the photoreceptor rough in this way, the attached talc can be easily removed. To make the OPC photoreceptor surface rough,
The surface of the CTL (see FIG. 9) may be buffed to increase its surface roughness.

[0027]

Effects of the Invention In the first method of the present invention, before an image forming operation is performed, the photoreceptor is uniformly charged, the uniformly charged portion is developed with toner, and the photoreceptor is cleaned by the cleaning device. Cleaning is performed to supply a predetermined amount or more of developing toner to the toner deturbator brush, and in the second method, uniform charging of the photoconductor, image exposure, and toner cleaning are performed at least within 300 times from the beginning. During the image forming operation by developing an electrostatic latent image and transferring the developed toner image onto paper, at least a part of the uniform exposure of the interimage area is stopped, so that a predetermined amount of toner is applied to the toner deturbation brush. Since the above-mentioned developing toner is supplied, at least before "image deletion" occurs, the toner collected will infiltrate and adhere between the flocked resin bristles of the roll-shaped toner deturbator brush. The bristles stand up, increasing mechanical hardness, and by preventing the bristles from falling down, the ability to remove talc exceeds the amount of talc deposited, so "image blur" caused by talc can be prevented.

As described above, according to the method for preventing image blurring in an image forming apparatus of the present invention, it is possible to use a special material without making any special modification to the image forming apparatus or with a slight program change. With a simple method, it is possible to prevent "image drift" that occurs at the initial stage of replacing the toner deturbator brush.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an example of an image forming apparatus to which an image blur prevention method of the present invention is applied.

FIG. 2 is a sectional view taken perpendicular to the rotation axis of the photoreceptor drum of the photoreceptor unit of the copying machine shown in FIG. 1;

3 is a sectional view taken along line III-III' in FIG. 2; FIG.

FIG. 4 is a diagram showing changes in image blur and talc fogging with respect to the number of copies when the photoreceptor unit is replaced with a new one.

FIG. 5 is a conceptual diagram showing the relationship between the amount of talc deposited and the amount of talc scraped off.

6 is a timing chart of each step when the first method of the present invention is applied to the copying machine of FIG. 1. FIG.

FIG. 7 is a diagram similar to FIG. 4 in that case.

8 is a timing chart of each step when the second method of the present invention is applied to the copying machine of FIG. 1. FIG.

FIG. 9 is a cross-sectional view of an OPC photoreceptor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Photosensitive unit, 3... Photosensitive drum, 4... Space inside the photosensitive drum, 5, 7... Cylindrical side plate, 9... Rotating shaft, 11... Housing, 13... Cylindrical part protruding from the housing to the inside of the unit, 15 ...Gears cut on the outer periphery of the side plate, 1
6...Positioning hole, 17...Brush for toner deturbator,
19... Rotating shaft of the toner deturbator brush, 21... Gear fixed to the rotating shaft of the toner deturbator brush,
22...Scraping member, 23...Cleaning blade,
25...Bottom plate of the housing, 27...Toner transport rotating paddle, 29...Toner transport rotating paddle rotation drive gear, 30...
Cleaning device, 31... Toner collection box, 32...
Partition wall between cleaning device and toner collection box, 3
3... Rotating shaft, 34... Plate member, 35... Toner transport auger, 37... Gear for auger rotation, 38... Torque limiter mechanism, 39... Circular opening provided in the front wall of the housing, 41... Hole, 43 ... Pipe, 45... Tip of auger, 47... Drive gear rotatably provided on the rear wall of the housing, 49... Float member, 51... Shielding member, 53... Projection made of transparent wall, 55... Groove into which the protrusion enters, 57... Light emitting element, 59... Light receiving element, 60... Full detection mechanism, 61... Charger, 80... Document, 81... Platen, 82... Exposure lamp, 83, 84, 85, 87, 88,
89...Mirror, 86...Lens, 92a...First developer for red toner, 92b...Second developer for black toner, 93...Transfer device, 94...Peeling corotron, 95...Peeling claw, 97...Interimage lamp , 100...Paper tray, 102...
Paper feed conveyance path, 103... Return conveyance path, 104... Conveyance path,
DESCRIPTION OF SYMBOLS 105...Fuser, 106...Discharge conveyance path, 108...Tray, 107...Gate, 110...Exposure device, 111...Transfer unit, 112...Fuser unit, 113...Erase lamp

Claims (1)

[Claims] 1. In order to clean residual toner on a moving organic photoreceptor, a cleaning means is arranged close to the photoreceptor, and resin bristles rotate in contact with the photoreceptor at a position upstream of the cleaning means. In an image forming apparatus having a cleaning device equipped with a rolled toner deturbator brush formed by flocking, at least after loading a new rolled toner deturber brush, uniform charging of the photoreceptor and image exposure are performed. , before performing an image forming operation by developing an electrostatic latent image with toner and transferring the developed toner image onto paper, uniformly charging the photoreceptor, developing the uniformly charged portion with toner, and cleaning the cleaning device. 1. A method for preventing image deletion in an image forming apparatus, the method comprising: cleaning a photoreceptor by cleaning a photoreceptor, and supplying a predetermined amount or more of developing toner to the toner deturbator brush. 1. In order to clean residual toner on a moving organic photoreceptor, a cleaning means is arranged close to the photoreceptor, and resin bristles rotate in contact with the photoreceptor at a position upstream of the cleaning means. The cleaning device is equipped with a roll-shaped toner deturbator brush formed by flocking, and forms an adjacent electrostatic latent image on the photoreceptor through the interimage area, and In an image forming apparatus that performs uniform charging, uniform exposure, development with toner, and cleaning, uniform charging of the photoreceptor and image formation at least within 300 times from the beginning after loading at least a new rolled toner deturbator brush. During image forming operations such as exposure, development of an electrostatic latent image with toner, and transfer of the developed toner image to paper, the toner deturbation process is performed by stopping at least a part of the uniform exposure of the interimage area. A method for preventing image deletion in an image forming apparatus, the method comprising supplying a predetermined amount or more of developing toner to a brush. 1. A method for preventing image deletion in an image forming apparatus according to claim 1, wherein the toner is a magnetic one-component toner.