JPH07239613A - Cleanerless image forming device - Google Patents

Abstract

PURPOSE:To prevent the toner on a photoreceptor from scattering outside the toner recoverable width of the developing device and to prevent a recording paper from soiling by the toner due to the cleaning defect. CONSTITUTION:The residual toner on a photoreceptor drum 2 after transferring is disturbed with a memory clearing blush 14 and uniformly dispersed on the photoreceptor drum 2. A developing unit 6 is provided with a developing roller 9 equipped with a magnet 22 inside, thus the residual toner dispersed on the photoreceptor drum 2 is recovered in the developing unit 6 by the electrostatic attracting force of the developing roller 9. A pair of a sponges 20 are arranged on the both end side in the width direction of the memory clearing blush 14 and closely stuck on the both end outer circumference of the photoreceptor drum 2. The distance H3 between the both sponges 20 is set a little shorter than the width H2 of the magnet 22 of the developing roller 9. The contact width of the memory clearing blush 14 with the photoreceptor drum 2 is regulated <= the distance H3 between the both sponges 20, even if bristles of the both end of the memory clearing blush 14 tends to extend outward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleanerless image forming apparatus applied to an electrophotographic recording type facsimile apparatus, a copying machine or the like.

[0002]

2. Description of the Related Art Generally, in an electrophotographic recording type image forming apparatus, after an electrostatic latent image is formed on a photosensitive drum by an exposing device, toner is attached to the electrostatic latent image by a developing device, and the electrostatic latent image is transferred by a transferring device. The toner is transferred onto recording paper. In this case, untransferred toner may remain on the photosensitive drum, but this residual toner should be collected by the developing device by electrostatic attraction at the same time as the toner is attached to the photosensitive drum by the developing device. There is a so-called cleanerless image forming apparatus.

As shown in FIG. 4, in this cleanerless image forming apparatus, the conductive brush 31 is arranged so as to extend along the axial direction of the photosensitive drum 32, and the tips of the respective bristles are the outer peripheral surface of the photosensitive drum 32. Is in contact with. Then, as the photosensitive drum 32 rotates, the toner remaining on the photosensitive drum 32 after the transfer is disturbed by the brush 31 and is uniformly dispersed on the photosensitive drum 32. Further, the developing device 33 is provided with a developing roller 34 for supplying the toner in the developing device 33 onto the photosensitive drum 32. At the same time as the toner supply operation by the developing roller 34, the residual toner dispersed on the photosensitive drum 32 is removed by the developing roller 3
The electrostatic attraction force of No. 4 causes the toner to be attracted onto the roller 34 and returned to the developing device 33. The developing roller 34 includes a cylindrical sleeve 34a that is positively rotated and a magnet 34b that is arranged inside the sleeve 34a. Then, the developing roller 34 is within the width H2 of the magnet 34b,
The toner T is supplied to and collected from the photosensitive drum 32. As described above, in the cleanerless image forming apparatus, the developing device 33 performs the developing operation and the cleaning operation in parallel without providing a dedicated cleaner for collecting the residual toner.

[0004]

By the way, in order to surely disperse the residual toner on the photosensitive drum 32 by the brush 31, the tips of the bristles of the brush 31 are arranged at the photosensitive drum 32.
It is necessary to press it to the outer peripheral surface with some force.
However, as shown in FIG. 4, in the conventional device, both widthwise end sides of the brush 31 are open, so that the brush 31 pressed against the photosensitive drum 32 has both ends in contact with the rotation of the photosensitive drum 32. Hair spreads out. Then, the contact width H1 of the brush 31 to the photosensitive drum 32 becomes larger than the width H2 of the magnet 34b of the developing roller 34, and the residual toner on the photosensitive drum 32 may be scattered to the outside of the magnet 34b. . In such a case, since the magnetic brush of toner is not formed on the portion outside the magnet 34b of the developing roller 34, the residual toner scattered to the outside cannot be collected by the developing device 33. Then, as shown in the same figure, the cleaning failure toner T is left in a streak-like state on the outer periphery of both ends of the photosensitive drum 32. As a result, during the transfer by the transfer device, the toner T having the cleaning failure is transferred to both ends of the recording paper, and the recording paper is contaminated.

The present invention has been made to solve the above problems, and an object thereof is to prevent the toner on the photoconductor from being scattered to the outside of the recoverable width of the toner by the developing device. An object of the present invention is to provide a cleanerless image forming apparatus which can be formed and in which the recording paper is not contaminated with toner that is poorly cleaned.

[0006]

In order to achieve the above-mentioned object, in the invention according to claim 1, the toner arranged on the photoconductor so as to be in contact therewith, and the toner remaining on the photoconductor after transfer is dispersed. In a cleanerless image forming apparatus including a brush for cleaning and a developing device for collecting the dispersed toner from a photoconductor, a contact width of the brush with respect to the photoconductor is provided on both end sides in the width direction of the brush. A regulation member is provided to regulate the width of the toner to be less than the recoverable width.

According to the second aspect of the invention, the developing device is provided with a developing roller having a magnet inside and adsorbing the residual toner on the photoconductor and returning it to the inside of the developing device. The interval is set to be equal to or less than the width of the magnet in the developing roller.

Further, in the invention as defined in claim 3, the regulating member is formed by a flexible member which is in close contact with the outer periphery of both ends of the photosensitive member.

[0009]

Therefore, according to the first aspect of the invention, the contact width of the brush with respect to the photoconductor is regulated by the regulation member to be equal to or less than the width in which the toner can be collected by the developing device. Therefore, even if the residual toner on the photoconductor is dispersed by the brush, the toner is not scattered outside the recoverable width of the toner by the developing device.

Further, according to the second aspect of the invention, the distance between the regulating members provided on both ends of the brush in the width direction is set to be equal to or less than the width of the magnet in the developing roller. The width of contact of the brush with respect to the width of the magnet does not exceed the width of the magnet, that is, the width in which the toner can be collected by the developing device.

Further, according to the third aspect of the invention, since the regulating member is in close contact with the outer periphery of both ends of the photoconductor, when the bristles at both ends of the brush try to spread outward, the bristles are regulated. There is no possibility of getting in between the member and the photoconductor. Therefore, the contact width of the brush with respect to the photoconductor is reliably prevented from exceeding the gap between the regulating members. Further, since the regulating member is formed of a flexible member, even if the regulating member is in close contact with the photoconductor, there is no possibility of damaging the photoconductor.

[0012]

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a photosensitive drum unit Y is arranged inside the apparatus frame 1.
The photosensitive drum 2 as a photosensitive member is supported in the photosensitive drum unit Y so as to be positively rotatable, and the photoconductive film 3 is provided on the outer peripheral surface thereof.
Are formed. The charger 4 is also arranged in the photosensitive drum unit Y and uniformly charges the photoconductive film 3 on the photosensitive drum 2 to a predetermined potential. The exposure device 5 is arranged above the photosensitive drum unit Y and forms an electrostatic latent image of a predetermined potential on the photosensitive drum 2 by irradiation of light.

The developing device 6 includes a toner case 7 for containing the toner T, a toner cartridge 8 detachably mounted on the toner case 7, and a lower end of the toner case 7 so as to face the photosensitive drum 2 closely. The developing roller 9 is provided in the opening. Then, the toner T in the toner case 7 is supplied onto the photosensitive drum 2 by the developing roller 9 while being charged to a predetermined potential, and based on the difference between the potential of the toner T and the potential of the electrostatic latent image. The toner T is attached to the electrostatic latent image, and the electrostatic latent image is visualized as a toner image.

The transfer device 10 and the guide roller 11 are arranged so as to face the photosensitive drum 2 with a sheet transfer path interposed therebetween. The guide roller 11 causes the photosensitive drum 2
The recording paper P is brought into close contact with the recording paper P, and a predetermined potential is applied to the close contact portion by the transfer device 10. Based on the difference between the potential and the potential of the toner image on the photosensitive drum 2, the toner image is recorded on the recording paper. Transcribed on P. After that, the recording paper P is sent to a heating fixing device (not shown), and the toner image on the recording paper P is heated and fixed by the heating fixing device.

The discharge lamp 12 is used for the photosensitive drum 2 after transfer.
The outer peripheral surface of is exposed to lower its surface potential,
Make the potential distribution uniform. The cleaning brush 13 is arranged in the photosensitive drum unit Y and removes paper dust and the like adhering to the photosensitive drum 2 after transfer. Memory removal brush 14 consisting of a large number of electrically conductive bristles such as carbon fibers
Is disposed in the photosensitive drum unit Y so as to face the outer peripheral surface of the photosensitive drum 2, and disturbs the toner T remaining on the photosensitive drum 2 after transfer, and uniformly disperses the toner T on the photosensitive drum 2. . The developing device 6 also performs a cleaning operation for collecting the residual toner T on the photosensitive drum 2 dispersed by the memory removing brush 14 by electrostatic attraction, in parallel with the developing operation. That is, at the same time when the toner T is supplied by the developing roller 9, the residual toner T dispersed on the photosensitive drum 2 is attracted onto the roller 9 by the electrostatic attraction force of the developing roller 9 and returned to the toner case 7. Be done.

As shown in FIGS. 1 and 3, the developing device 6
Of the developing roller 9 extends along the axial direction of the photosensitive drum 2. The developing roller 9 includes a cylindrical magnet 22 fixed on a support shaft 21, and a cylindrical sleeve 2 rotatably supported around the magnet 22.
3 and 3. This sleeve 23 is for the magnet 2
The bearings 24 are supported on the support shaft 21 at both widthwise end sides of the bearing 2, and are positively rotated by a motor (not shown). Then, the developing roller 9 supplies and collects the toner T to the photosensitive drum 2 described above within the range of the width H2 of the magnet 22.

As shown in FIGS. 1 to 3, a casing 15 is fixed to the lower portion of the photosensitive drum unit Y by screws 16. The casing 15 has a substantially U-shaped cross section and extends along the axial direction of the photosensitive drum 2.
The cleaning brush 13 is attached to the internal space of the casing 15. In addition, a support frame 17 made of sheet metal is suspended and fixed by screws 18 in the internal space of the casing 15, and the memory removal brush 14 is fixed by screws 19 at the lower end of the support frame 17. The memory removing brush 14 is arranged so as to extend along the axial direction of the photosensitive drum 2, and the tips of the bristles thereof are pressed against the outer peripheral surface of the photosensitive drum 2.

The pair of sponges 20 as the regulating members are
The memory removing brush 14 is attached to both end portions of the casing 15 so as to be located on both end sides in the width direction, and is in close contact with outer peripheral surfaces of both ends of the photosensitive drum 2. The interval H3 between the sponges 20 is set to be slightly smaller (about several millimeters) than the width H2 of the magnet 22 of the developing roller 9. The width of the memory removal brush 14 located between the sponges 20 is equal to the space H3 between the sponges 20.
It is set to be slightly smaller (a few millimeters).

In the present embodiment, when the photosensitive drum 2 is rotated and the image forming operation is started, the toner T remaining on the photosensitive drum 2 after transfer is disturbed by the memory removing brush 14, It is evenly dispersed on the photosensitive drum 2. At this time, the bristles at both ends in the width direction of the memory removal brush 14 pressed against the photosensitive drum 2 try to spread outward as the photosensitive drum 2 rotates. However, in the present embodiment, the pair of sponges 20 are disposed on both widthwise end sides of the memory removal brush 14. Therefore, even if the bristles on both ends of the memory removing brush 14 try to spread outward, the bristles are prevented from coming into contact with the sponge 20 and spreading, so that the contact width of the memory removing brush 14 with respect to the photosensitive drum 2 is reduced. The distance between the sponges 20 is regulated to the distance H3 or less. In addition, in this embodiment, both sponges 20 are used.
The interval H3 between them is the width H2 of the magnet 22 of the developing roller 9.
Since it is set to be slightly smaller, the contact width of the memory removal brush 14 with respect to the photosensitive drum 2 does not exceed the width H2 of the magnet 22, that is, the recoverable width of the toner T by the developing device 6.

Therefore, the residual toner T on the photosensitive drum 2 is
However, it is not scattered outside the magnet 22 of the developing roller 9 due to the disturbing operation by the memory removing brush 14. Therefore, all the residual toner T on the photosensitive drum 2 can be reliably collected in the developing device 6 by the developing roller 9, and as a result, unlike the prior art, the recording paper P is the toner T that is not cleaned properly. There is no possibility of getting dirty.

Further, in this embodiment, since the sponge 20 is in close contact with the outer peripheral surfaces of both ends of the photosensitive drum 2, when the bristles on both ends of the memory removing brush 14 try to spread outward, the bristles are sponged. There is no possibility of getting in between the and the photosensitive drum 2. Therefore, it is possible to reliably prevent the contact width of the memory removal brush 14 from the photosensitive drum 2 from exceeding the interval H3 between the sponges 20. Further, since the member that is in close contact with the photosensitive drum 2 is the flexible sponge 20, the sponge 20 allows the photosensitive drum 2 to move.
There is no possibility that the upper photoconductive film 3 will be damaged. Moreover, even if the sponge 20 slides on the photosensitive drum 2, since a large frictional force does not act, the rotation of the photosensitive drum 2 is not hindered.

The present invention is not limited to the above-mentioned embodiment, and the constitution of each part may be modified and embodied as follows. (1) The distance H3 between both sponges 20 is made equal to the width H2 of the magnet 22 of the developing roller 9. Alternatively, the width of the memory removal brush 14 should be the same as the space H3 between the sponges 20. Even in such a case, it is possible to obtain the same effects as those of the above-mentioned embodiment.

(2) Use felt instead of the sponge 20 as the regulating member. Even in this case, it is possible to obtain the same effect as that of the sponge 20. (3) As the memory removal brush 14, a brush having a large number of bristles radially provided on the rotating shaft is used, and the brush is used to disturb the residual toner T on the photosensitive drum 2 while actively rotating. .

[0024]

As described above in detail, according to the present invention,
It is possible to prevent the toner on the photoconductor from being scattered to the outside of the recoverable width of the toner by the developing device, and it is possible to exert an excellent effect that the recording paper is not contaminated with the toner that is not cleaned well. Further, there is an effect that the contact width of the brush with respect to the photoconductor can be reliably prevented from exceeding the gap between the regulating members, and the photoconductor is not damaged.

[Brief description of drawings]

FIG. 1 is a partial side sectional view showing an embodiment of a cleanerless image forming apparatus embodying the present invention.

FIG. 2 is a front view of relevant parts showing a memory removal brush attached to a casing and sponges located on both end sides thereof.

FIG. 3 is a plan view of relevant parts showing the relationship between the distance between both sponges and the width of the magnet of the developing roller.

FIG. 4 is a plan view of relevant parts showing a relationship between a contact width of a brush with respect to a photosensitive drum and a width of a magnet of a developing roller in a conventional technique.

[Explanation of symbols]

2 ... Photosensitive drum as photoconductor, 6 ... Developing device, 9 ... Developing roller, 14 ... Memory removing brush, 15 ... Casing,
20 ... Sponge as a regulating member, 22 ... Magnet,
T ... toner, H2 ... magnet width, H3 ... spacing between sponges.

Claims (3)

[Claims] 1. A brush, which is arranged so as to be in contact with a photoconductor and which disperses toner remaining on the photoconductor after transfer,
In a cleanerless image forming apparatus equipped with a developing device for collecting the dispersed toner from the photoconductor, the width of contact of the brush with the photoconductor is set at both ends in the width direction of the brush, and the toner is collected by the developing device. A cleanerless image forming apparatus provided with a regulation member that regulates the width to be less than or equal to the possible width. 2. The developing device includes a developing roller having a magnet inside and adsorbing the residual toner on the photoconductor to return the toner to the inside of the developing device, and the gap between the regulating members is set to a value of the magnet in the developing roller. The cleanerless image forming apparatus according to claim 1, wherein the width is less than or equal to the width. 3. The cleanerless image forming apparatus according to claim 1, wherein the regulating member is formed of a flexible member that is in close contact with outer circumferences of both ends of the photoconductor.