JP2000227743A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device making paper dust surely removed even in the case of adopting acidic paper as transfer material, and being free from the occurrence of filming on a photoreceptor or an intermediate transfer body. SOLUTION: On a leading end part of urethane sheet 82 composed of the urethane rubber, non-woven cloth 81 is affixed by double coated adhesive tape, and the urethane sheet 82 is affixed by double coated adhesive tape on the top surface of a holder 83, so that the trailing end part of the urethane sheet 82 is held in contact with a positioning project part 84 on the holder 83. The length of this urethane sheet 82 and the position of the positioning project part 84 is respectively set so that the non-woven cloth 81 is held in contact with the photosensitive drum in a state of loosening the urethane sheet 82. Moreover, the loosening direction is made to match with the rotary direction of the photoreceptor drum 20. In this way, the paper dust removing device is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper dust removing method for removing a paper dust on a photoconductor or an intermediate transfer member by bringing the toner image into contact with a photosensitive member or an intermediate transfer member which carries and transports a toner image to a transfer material. It belongs to the technical field of an image forming apparatus provided with a means.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus for forming an image by transferring a toner image on a photosensitive member or an intermediate transfer member to paper, transfer residual toner on the photosensitive member or the intermediate transfer member is bladed or the like. A so-called cleaner-less development system in which a developer is collected and reused without scraping is used. In such a method, it is not necessary to provide a cleaner device, so that it has an advantage that the device can be reduced in size and cost. On the other hand, the paper dust generated from the paper is also collected by the developing device, and the paper is removed. There is a disadvantage that the powder is developed on a base or the like and printing defects occur.

[0003] In particular, when acidic paper is used as printing paper,
Talc, a filler contained in the acid paper, is mixed into the developing unit,
There is a problem that remarkable printing defects occur.

Therefore, an image forming apparatus has been proposed in which a paper dust removing means comprising a rotary brush is provided between the transfer means and the developing device. According to this image forming apparatus, the fibers contained in the paper dust can be satisfactorily removed by the rotary brush, and printing defects can be reduced.

[0005]

However, when a rotary brush is used as in the conventional image forming apparatus, the fibers contained in the paper dust can be removed satisfactorily by brushing. It is difficult to remove a filler component such as talc with a brush, so that talc cannot be removed, and there is a problem that talc is mixed into a developing device.

In order to solve this problem, there has been proposed an improvement such as making the brush fibers loop-shaped, for example, in Japanese Patent Laid-Open No. 1-116.
Although disclosed in Japanese Patent Application Laid-Open No. 677, 677, etc., even when such an improved brush was used, talc could not be sufficiently removed.

In order to solve such a problem, a method has been proposed in which a non-woven fabric is wound around a rotating elastic body, and the paper dust is removed by rotating the non-woven fabric so as to come into contact with a photoreceptor. 62-181973).

However, in this method, the nonwoven fabric is pressed against the photoreceptor, so that the paper dust can be removed satisfactorily. However, the paper dust captured by the nonwoven fabric is strongly rubbed against the photoreceptor. Another problem is that filming by talc occurs on the photoreceptor.

Further, in this method, a mechanism for rotating and driving the elastic body is required, so that the structure is complicated, and there is a problem that the process cartridge including the photosensitive drum becomes large.

In view of the above problems, the present invention can reliably remove paper dust even when acidic paper is used as a transfer material, and cause filming on a photosensitive member or an intermediate transfer member. It is an object of the present invention to provide an image forming apparatus that does not have any problem.

[0011]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: developing an electrostatic latent image formed on a photoreceptor with a developer to form a visible image; An image forming apparatus for forming an image by forming and transferring the visible image to a transfer medium, comprising: a visible image carrier that carries and conveys the visible image to the transfer position; Paper dust removing means for removing paper dust on the body, wherein the paper dust removing means is made of a fiber made of any one of a nonwoven fabric, a woven fabric, or a knitted material on a substrate made of a sheet-like member. A member is attached, and the base member is positioned so as to bring the fiber member into contact with the visible image carrier.

According to the image forming apparatus of the first aspect,
When the visible image carrier carries and transports a visible image composed of a developer to a transfer position, the visible image is transferred to a transfer medium,
When paper is used as the transfer medium, paper powder adheres to the visible image carrier in this transfer step. However, since the visible image carrier is provided with a fibrous member made of any one of a nonwoven fabric, a woven fabric, and a knitted material on a base material made of a sheet-shaped member, paper powder is reliably removed. To be removed. After the removal, there is also paper dust accumulated in the contact portion between the fiber member and the visible image carrier. However, the fiber member is caused by the bending of the base member made of a sheet-like member. , The contact pressure is low, and there is no occurrence of damage or filming of the visible image carrier due to accumulated paper dust.

According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the image forming apparatus according to the first aspect, the base material of the paper dust removing means has at least the visible image carrying means. When the body is driven, it is positioned so as to be elastically deformed in the same direction as the direction in which the visible image is carried and conveyed by the visible image carrier.

According to the image forming apparatus of the second aspect,
When the visible image carrier is driven, the base material of the paper dust removing unit is elastically deformed in the same direction as the direction in which the visible image is carried and conveyed by the visible image carrier. Therefore, even if paper dust conveyed in the same direction as the direction in which the visible image is carried and conveyed accumulates in the contact portion between the fiber member and the visible image carrier, the base material prevents elastic deformation in the direction. Therefore, the pressing force against the paper powder hardly increases. As a result, the damage or filming is more reliably prevented.

According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect, wherein the fiber member and the visible image carrier are connected to each other. A paper dust removing means comprising a brush-like member is further provided between the contact position and the transfer position at which the transfer is performed.

According to the image forming apparatus of the third aspect,
The paper dust adhered to the visible image carrier after the transfer is conveyed by the visible image carrier to the contact position of the fiber member with the visible image carrier, but between the transfer position and the contact position. Since the paper dust removing means comprising a brush-like member is further provided, of the paper dust, fibrous large paper dust is removed by this brush-like member, and the fiber member and the visible image carrier are removed. It does not reach the contact position. As a result, accumulation of large fibrous paper dust at the contact position of the fiber member with the visible image carrier is reliably prevented, and damage to the visible image carrier is more reliably prevented. . In addition, the accumulation locations of the paper dust are dispersed in two places, and the life of the paper dust removing means is prolonged.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the base material is a resin sheet. It is characterized by being formed from a shaped member.

According to the image forming apparatus of the fourth aspect,
The fiber member is attached to a substrate formed from a resin sheet member. Therefore, the fiber member comes into contact with the visible image carrier with an extremely small contact pressure, and damage or filming of the visible image carrier is reliably prevented.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the base material is a rubber sheet. It is characterized by being formed from a shaped member.

According to the image forming apparatus of the fifth aspect,
The fiber member is attached to a base member formed from a rubber sheet member. Therefore, the fiber member comes into contact with the visible image carrier with an extremely small contact pressure, and damage or filming of the visible image carrier is reliably prevented.

According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the developer is obtained by polymerization. Characterized in that it is a polymerized toner.

According to the image forming apparatus of the sixth aspect,
Since the developer is a polymerized toner obtained by polymerization, it has a smoother surface shape and higher fluidity than the pulverized toner, and is less likely to adhere to the paper dust removing means. Further, since the fluidity is high, rubbing between toners is small, and toner remaining after transfer is reduced. As a result, the toner is hardly captured at the contact position of the fiber member with the visible image carrier, and the ability of the fiber member to remove paper dust is not reduced.

According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, in order to solve the above-mentioned problem, the transfer residual developer is supplied to the developing device. And a cleaner-less developing method in which the developer is used again for development.

According to the image forming apparatus of the present invention,
The untransferred developer remaining on the visible image carrier after the transfer step is collected by a developing device and subjected to development again, but the paper dust on the visible image carrier is removed by the above-described paper dust removing means. Therefore, paper powder is not mixed when the transfer agent developer is collected in the developing device. Therefore, image defects such as fogging do not occur.

According to an eighth aspect of the present invention, there is provided an image forming apparatus as set forth in any one of the first to seventh aspects, wherein the visible image carrier is
It is characterized in that the photoreceptor doubles.

According to the image forming apparatus of the present invention,
The visible image formed by development is carried on the photoconductor,
It is carried and conveyed to a transfer position and is transferred to a transfer medium. Accordingly, paper dust adheres to the photoreceptor, but the paper dust is surely removed by the paper dust removing means, so that an image defect does not particularly occur when a visible image is formed on the photoreceptor.

According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the visible image carrier may be It is characterized by comprising an intermediate transfer member provided endlessly movably facing the photosensitive member.

According to the image forming apparatus of the ninth aspect,
The visible image formed by development is carried on the photoconductor,
The image is transferred to an intermediate transfer member that is provided so as to be movable endlessly opposite to the photoconductor. Then, the image is retransferred from the intermediate transfer member to a transfer medium. Therefore, paper dust adheres to the intermediate transfer member, but the paper dust is surely removed by the paper dust removing means, so that the transfer of the paper dust from the intermediate transfer member to the photoconductor or the intermediate transfer Prevents transfer of paper powder from the body to the transfer medium, and does not cause image defects.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a sectional view showing a schematic configuration of a laser beam printer 1 as an embodiment of the image forming apparatus of the present invention. In FIG. 1, the laser beam printer 1 includes a feeder unit for feeding paper (not shown) at the bottom of a main body case 2. The feeder unit includes a sheet pressing plate 10 urged upward by a spring (not shown), a sheet feeding roller 11, and a sheet feeding roller 11.
And a friction separating member 14 pressed against The paper stacked on the paper pressing plate 10 is pushed up so as to come into contact with the paper feed roller 11, and is fed at a predetermined timing.
Is rotated in the direction of the arrow in FIG. 1 so that only the uppermost sheet is separated and supplied between the sheet feeding roller 11 and the friction separating member 14.

A pair of registration rollers 12 and 1 are located on the downstream side in the sheet conveyance direction due to the rotation of the paper feed roller 11.
3 is rotatably supported, and conveys a sheet at a predetermined timing to a transfer position formed by a photosensitive drum 20 and a transfer roller 21, which will be described later.

The photosensitive drum 20 as a visible image carrier is
It is made of a positively chargeable material, for example, an organic photoreceptor mainly containing positively chargeable polycarbonate. More specifically, the photosensitive drum 20 has, for example, a cylindrical aluminum sleeve as a main body, and has a predetermined thickness (for example, about 20 μm) in which a photoconductive resin is dispersed in polycarbonate on an outer peripheral portion thereof.
m) is constituted by a hollow drum formed with a photoconductive layer, and is rotatably supported by the main body case 2 with the cylindrical sleeve grounded. Further, the photosensitive drum 20 is driven to rotate in a direction indicated by an arrow by driving means (not shown).

The charger 30 is, for example, a scorotron-type charger for positive charging that generates corona discharge from a charging wire made of tungsten or the like.

The laser scanner unit 40 includes a laser generator (not shown) for generating a laser beam L for forming an electrostatic latent image on the photosensitive drum 20, and a polygon mirror (pentahedral mirror) 41 which is driven to rotate. , A pair of lenses 42 and 4
5 and reflection mirrors 43, 44 and 46.

The developing device 50 has a case 51 in which a toner storage chamber 52 as a developer chamber is formed.
An agitator 53 is provided inside 2 so as to be rotatable around a rotation shaft 54. The toner stored in the toner storage chamber 52 is a positively chargeable non-magnetic one-component developer,
A particle size of 6 μm obtained by adding a well-known coloring agent such as carbon black and a charge controlling agent such as nigrosine, triphenylmethane and quaternary ammonium salt to a styrene-acrylic resin formed into a spherical shape by suspension polymerization. It has toner base particles having a particle diameter of 10 μm to 10 μm and an average particle diameter of 8 μm. The toner 55 is configured by adding silica as an external additive to the surface of the toner base particles.

The photosensitive drum 20 in the toner storage chamber 52
On the side, a developing chamber 55 for performing development by communicating with the toner storage chamber 52 through an opening A is formed, and a supply roller 56 and a developing roller 57 are rotatably pivotally supported. The toner on the developing roller 57 is regulated to a predetermined layer thickness by a layer-thickness regulating blade 58 provided with a contact portion made of silicone rubber at the tip of a thin plate-like elastic metal plate, and is used for development.

The transfer roller 21 is rotatably pivotally supported,
It is made of a conductive foamed elastic body made of silicone rubber or urethane rubber. The transfer roller 21 is configured to reliably transfer the toner image on the photosensitive drum 20 to the paper by the applied voltage.

The fixing unit 70 includes the registration roller 12
The heating roller 71 and the pressing roller 72 are provided on the further downstream side in the sheet conveyance direction from the sheet feeding roller 13 to the pressure contact portion between the photosensitive drum 20 and the transfer roller 21. The toner image transferred to the sheet is pressed while being heated and is fixed on the sheet.

A pair of transport rollers 73 for transporting the paper are provided downstream of the fixing unit 70 in the transport direction, and a pair of discharge rollers 7 are located downstream of the transport roller 73.
4 and a paper discharge tray 75 are provided in this order.

Further, a paper dust removing device 80 provided as a paper dust removing means provided adjacent to the photosensitive drum 20 is provided with a holder 8.
3 and a urethane sheet 82 whose base end is supported on the upper part of the holder 83 and whose front end is covered with a nonwoven fabric 81.

As the nonwoven fabric 81 as a fiber member, a nonwoven fabric integrated by confounding constituent fibers was used. This is because it is preferable to use a constituent fiber having a high degree of freedom in capturing fine paper powder between the fibers. As a constituent material, for example, synthetic fibers such as polyester fibers, polyamide fibers, polyolefin fibers, acrylic fibers, or composite fibers using resins of these fibers, semi-synthetic fibers such as acetate fibers, Alternatively, a recycled fiber such as cupra or rayon, a natural fiber such as wire, hemp, wool, or a fiber member such as a cotton blend is used.

The nonwoven fabric 81 is impregnated with an oil agent. As the oil agent, an oil agent containing at least one of mineral oil, synthetic oil, silicone oil and surfactant was used. As the mineral oil, paraffinic hydrocarbons, naphthenic hydrocarbons, aromatic hydrocarbons and the like are used. As the synthetic oil, an alkylbenzene oil, a polyolefin oil, a polyglycol oil, or the like is used. Further, as the silicone oil, chain dimethylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, various modified silicones and the like are used. As the surfactant, a quaternary ammonium salt type or the like is preferable as a cationic type, and a polyethylene glycol type or a polyhydric alcohol type or the like is preferable as a nonionic type. In the present embodiment, such an oil agent is supported at a ratio of 1 to 20% based on the weight of the nonwoven fabric 81.

In the present embodiment, the above-described nonwoven fabric 81 is formed by combining the non-woven fabric 81 with a length substantially equal to the length of the photosensitive drum 20 in the longitudinal direction.
It was formed so as to have a length in the longitudinal direction of 25 mm, and was attached to the front end portion of a urethane sheet 82 as a substrate made of a sheet-like member using a double-sided tape. As shown in FIG. 2, which is an enlarged view showing the periphery of the paper dust removing device 80 in FIG. 1, the nonwoven fabric 81 was attached to the front end of the urethane sheet 82 so as to be folded in two from the center. Then, positioning was performed such that the rear end of the urethane sheet 82 was brought into contact with a positioning projection 84 formed on the upper part of the holder 83. As shown in FIG. 3, which is a perspective view showing the holder 83, the positioning projection 84 is formed integrally with the holder 83 on the upper surface of the holder 83.

The urethane sheet 82 as a base material is a sheet member made of urethane rubber and has a hardness of 9
2 ゜ Hs (JIS K-6301). As for the size, the thickness was 100 μm, the width was 6 mm, and the length in the longitudinal direction was 225 mm.

When the rear end of the urethane sheet 82 is brought into contact with the positioning projection 84, the front end of the urethane sheet 82 and the nonwoven fabric 81 are indicated by a dotted line in FIG. As shown, the length reaches the position where the photosensitive drum 20 is provided. Therefore, when the photosensitive drum 20 is provided at a predetermined position as shown in FIG. 2, the urethane sheet 82 to which the nonwoven fabric 81 is adhered is bent as shown in FIG.
Will be in contact with As a result, the nonwoven fabric 81 comes into contact with the urethane sheet 82 by the pressing force due to the elasticity of the urethane sheet 82 over substantially the entire width in the longitudinal direction of the photosensitive drum 20. Note that the bending direction of the urethane sheet 82 at this time is set to a direction that coincides with the rotation direction when the photosensitive drum 20 is driven to rotate.

Since the hardness of the urethane sheet 82 is as low as 92 ° Hs, the length of the free length portion of the urethane sheet 82 that causes the flexure of the urethane sheet 82 can be reduced. Therefore, there is an advantage that the paper dust removing device 80 can be made compact. Further, since the hardness is low, even when the urethane sheet 82 is bent as described above, the nonwoven fabric 81 at the leading end can be softly brought into contact with the photosensitive drum 20. In the present embodiment, the pressing force of the nonwoven fabric 81 supported by the urethane sheet 82 against the photosensitive drum 20 was as low as 2.5 gf / cm when measured using a dial tension gauge.

The holder 83 has substantially the same length as the photosensitive drum 20 in the longitudinal direction of the photosensitive drum 20, and supports the photosensitive drum 20 at both ends in the longitudinal direction with screws 91. Screwed to the frame.
Further, a paper powder storage chamber is formed inside the photosensitive drum 2.
An opening is formed on the side opposite to 0. Further, a urethane film 87 is attached to a lower portion of the holder 83. The base end of the urethane film 87 is attached to the holder 83 using a double-sided tape, and the free end side is in contact with the photosensitive drum 20. By providing such a urethane film 87, it is possible to prevent paper powder from falling from the storage chamber of the holder 83. Further, as described above, the positioning projection 84 shown in FIG. 3 is formed on the upper portion of the holder 83, and the urging surface 8 of the urethane sheet 82 is provided in front of the positioning projection 84.
5 are provided. The urethane sheet 82 is attached to the attachment surface 85 using a double-sided tape.

In the laser beam printer 1 of the present embodiment as described above, the surface of the photosensitive drum 20 is
When the laser beam L modulated according to image information is emitted from the laser scanner unit 40, an electrostatic latent image is formed on the surface of the photosensitive drum 20.
This electrostatic latent image is visualized with toner by the developing device 50, and the visible image formed on the photosensitive drum 20 is transported by the photosensitive drum 20 to a transfer position. At the transfer position, the paper is supplied via the paper feed roller 11 and the registration rollers 12 and 13, and the visible image is transferred to the paper by a transfer bias applied by the transfer roller 21.

Next, the sheet is conveyed to the fixing unit 70, and is nipped and conveyed by the heating roller 71 and the pressing roller 72 of the fixing unit 70. The visible image on the sheet is pressed and heated to be fixed on the sheet. You. Then, the sheet is discharged to the discharge tray 75 above the laser beam printer 1 by the pair of transport rollers 73 and the discharge rollers 74, and the image forming operation is completed.

On the other hand, the toner remaining on the photosensitive drum 20 after the transfer is collected by the developing device 50 and is again subjected to development. As described above, the laser beam printer 1 of the present embodiment
Employs a so-called cleaner-less development method.
Therefore, since a waste toner storage container for scraping and storing the toner remaining on the photosensitive drum 20 is not required, the size of the apparatus can be reduced, and the toner can be effectively used.

Paper dust adheres to the photosensitive drum 20 after the transfer, and this paper dust is transported to the pressing portion between the nonwoven fabric 81 of the paper dust removing device 80 and the photosensitive drum 20 with the rotation of the photosensitive drum 20. Is removed by the nonwoven fabric 81.

In this embodiment, the pressing force of the nonwoven fabric 81 against the photosensitive drum 20 is set to an extremely low value of 2.5 gf / cm. However, since the nonwoven fabric 81 is removed by entanglement of the paper dust, Paper powder can be reliably removed even with such a low pressing force. Although the paper powder contains the fiber component and the filler, the nonwoven fabric 81 can reliably remove both the fiber component and the filler. Also,
Since the pressing force of the non-woven fabric 81 against the photosensitive drum 20 is kept low, the damage of the surface of the photosensitive drum 20 due to the fiber component of the paper powder and the filming due to the filler do not occur.

Here, the relationship between paper dust, damage to the surface of the photosensitive drum 20 and filming will be described in detail.
In addition to pulp fiber (cellulose extracted from hardwood and softwood), which is the main raw material for paper, fillers that make paper opaque and white, internal sizing agents to prevent ink bleeding, and sizing agents And an internal-size fixing agent that causes pulp fibers to be adsorbed. The above-mentioned acidic paper mainly uses talc or clay as a filler, a rosin sizing agent as an internal sizing agent, and a sulfate band (aluminum sulfate) as an internal sizing agent.

Among these, pulp fibers and filler talc are particularly adversely affecting the electrophotographic process. When pulp fibers are mixed in a developing device using a non-magnetic one-component developer, the pulp fibers may be caught between the layer thickness regulating blade and the developing roller, and may damage the layer thickness regulating blade and the developing roller. Further, when the pulp fiber passes through the layer thickness regulating blade together with the toner stuck to the pulp fiber and adheres to the paper, and is discharged as it is through the fixing process, it is conspicuous particularly when it adheres to a white background portion. It will be recognized by the naked eye as garbage. On the other hand, talc is a very strongly negatively charged substance, and in a process using a positively charged toner, if it is mixed in a developing device, the amount of charge of the toner is reduced to cause printing fog. Further, in a process using a negatively charged toner, similarly, it may cause print fogging, or even if not fog, the charge amount of the toner becomes excessively high, causing a decrease in image density. is there.

In order to remove such paper dust, an apparatus in which a paper dust removing means using a brush roller, a nonwoven fabric roller or the like is brought into contact with a photosensitive drum has been proposed. Although the fiber component can be captured, the small filler component cannot be sufficiently captured.

On the other hand, the non-woven fabric roller can capture both the fiber component and the filler component of the paper powder. For this purpose, a structure is used in which the non-woven fabric roller is strongly pressed against the photosensitive drum, and the captured hard pulp fiber is used for the photosensitive drum. There was a problem of damaging the surface. Further, when the filler is accumulated on the nonwoven fabric roller, while the soft filler is pressed and rubbed between the photosensitive drum surface and the nonwoven fabric roller or between the photosensitive drum surface and the pulp fiber accumulated on the nonwoven fabric roller,
The filler thinly adheres to the surface of the photosensitive drum, and a phenomenon called filming occurs. When filming occurs, the charged potential of the photosensitive drum surface before and after the exposure changes, making it impossible to form an appropriate image or causing poor transfer of the toner due to poor toner releasability. was there.

On the other hand, in the present embodiment, in order to solve the above-mentioned problems, the nonwoven fabric 81 is formed by the elastic force of the urethane sheet 82 having a low hardness.
And the pressing force of the nonwoven fabric 81 against the photosensitive drum 20 is suppressed to an extremely low value of 2.5 gf / cm. Therefore, the hard pulp fibers captured by the nonwoven fabric 81 do not damage the surface of the photosensitive drum 20, and filming due to the filler does not occur.

Since the nonwoven fabric 81 is attached to the front end of the urethane sheet 82 so as to be folded from the center, the contact area of the front end of the nonwoven fabric 81 with the photosensitive drum 20 is very small, and The occurrence of filming can be more reliably prevented.

Further, the bending direction of the urethane sheet 82 is
Since it is set in the same direction as the rotation direction of the photosensitive drum 20, even if paper dust accumulates at the pressing portion between the nonwoven fabric 81 and the photosensitive drum 20, the pressure against the paper dust is hard to increase, and the above-described damage and filming Can be more reliably prevented.

On the other hand, since the nonwoven fabric 81 is removed by entanglement of the paper dust, the paper dust can be reliably removed even when such a low pressing force is set, and the paper dust is mixed into the developing device 50. To prevent the occurrence of image defects.

Further, since the nonwoven fabric 81 is impregnated with the above oil agent, paper powder such as pulp fiber or talc can be reliably removed by the cohesive force of the oil agent.
In particular, even when acidic paper is used as the paper, the components of the paper (particularly, talc) can be reliably removed, and image defects such as fog can be reliably prevented.

In this embodiment, the nonwoven fabric 81
Is low, the amount of transfer of the oil agent to the photosensitive drum 20 is minimized, whereby the oil agent does not adhere to the photosensitive drum 20 in a large amount, and filming by the oil agent is prevented. Can be prevented. Further, filming due to soft talc as described above can be prevented.

Further, in the present embodiment, since the polymerized toner produced by the polymerization method is used as the toner, the toner base particles have a substantially spherical and gentle surface shape, and the transfer efficiency is high due to the high fluidity. And the residual toner itself is very small. Even if a very small amount of toner remains on the photosensitive drum 20, the nonwoven fabric 81
And is reliably collected by the developing device 50. As a result, the toner is not caught by the pressing portion between the non-woven fabric 81 and the photosensitive drum 20, and the non-woven fabric 8
1 does not lower the paper powder removing ability.

As described above, according to the present embodiment, it is possible to reliably remove the paper dust composed of the fiber component and the filler by the paper dust removing device 80 without causing damage to the surface of the photosensitive drum 20 or filming. Since pulp fibers and talc are not mixed into the developing device 50 and transfer of the pulp fibers to the paper does not occur, image defects such as fog or paper stains can be reliably prevented. As an example, when an experiment was performed to form a continuous image of up to 15,000 sheets using acidic paper, no damage or filming of the photosensitive drum 20 occurred, and the image was good.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, as shown in FIG. 4, a brush-like member 86 for scraping paper dust is provided upstream of the nonwoven fabric 81 attached to the urethane sheet 82 in the rotation direction of the photosensitive drum 20. However, this is different from the first embodiment.

By providing such a brush-like member 86, large fibrous paper dust is caught by the brush-like member 86, and large fibrous paper dust accumulates at the pressing portion between the nonwoven fabric 81 and the photosensitive drum 20. Can be reliably prevented.

As a result, streak-like damage on the surface of the photosensitive drum 20 due to fibrous paper dust can be reliably prevented. The fibrous paper dust also accumulates at the contact portion between the brush-like member 86 and the photosensitive drum 20.
Is extremely low, so that no streak-like damage is generated on the surface of the photosensitive drum 20.

As described above, the portion where the paper dust accumulates is the contact portion between the brush-like member 86 and the photosensitive drum 20,
Since it is dispersed at two places of the pressing part between the nonwoven fabric 81 and the photosensitive drum 20, the paper dust removing ability at the contact part and the pressing part can be favorably maintained for a long time, and the height of the paper dust removing device 80 can be improved. Life extension can be realized.

The brush-like member 86 may be a sheet on which fibers are planted. In the present embodiment,
A brush made of acrylic fiber, 500D (denier) / 50F (filament), and density of 50,000F (per square inch) was used. Further, large fibrous paper dust accumulates at the contact portion between the brush-like member 86 and the photosensitive drum 20, and fine paper dust such as filler accumulates at the pressing portion between the nonwoven fabric 81 and the photosensitive drum 20, so that the photosensitive drum The non-woven fabric 81 and the photosensitive drum 2 are larger than the space on the upstream side of the contact portion between the brush member 86 and the photosensitive drum 20 in the rotation direction of the photosensitive drum 20.
The space on the upstream side of the pressing portion with 0 may be narrow.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

This embodiment is different from the above-described embodiment in that PET (polyethylene terephthalate) is used as the sheet-like member for supporting the nonwoven fabric 81 instead of urethane rubber.

PET is generally higher in hardness than urethane rubber, but increases the length of a free-length portion causing deflection.
In addition, if the pressure on the photosensitive drum 20 can be suppressed by reducing the thickness, the sheet-shaped member can be used instead of urethane rubber.

In the present embodiment, a PET sheet having a thickness of 50 μm, a width of 16 mm, and a length of 225 mm in the longitudinal direction was formed, the thickness was smaller than the urethane sheet 82, and the width was larger than the urethane sheet 82. Then, as shown in FIG. 5, the urethane sheet 89 is attached to the holder 87 using a double-sided tape so that the rear end of the PET sheet 89 comes into contact with the positioning protrusion 88 formed on the upper surface of the holder 87. Pasted. The holder 87 has a sticking surface 90 formed larger than the holder 83 as shown in FIG. 6 in order to stick a PET sheet 89 having a width larger than that of the urethane sheet 82. Was attached to the attachment surface 90 using a double-sided tape. The positioning projection 88 provided on the upper surface of the holder 87 extends in the longitudinal direction by integral molding with the holder 87.

The length of the PET sheet 89 is such that when the rear end thereof is brought into contact with the projection 88 of the holder 87 and the photosensitive drum 20 is not provided, the leading end of the PET sheet 89 and the nonwoven fabric 81 are indicated by a dotted line in FIG. Is the length that reaches the position where the photosensitive drum 20 is provided.

Therefore, as shown in FIG.
Is placed at a predetermined position, the PET sheet 89 bends as shown in FIG.
The photosensitive drum 20 is brought into contact with the pressing force due to the elasticity of the photosensitive drum 20. Note that the bending direction of the PET sheet 89 is the same as the rotation direction of the photosensitive drum 20, as in the above-described embodiment.

The pressing force of such a PET sheet 89 is
When measured using a dial tension gauge as in the first embodiment, the value was as extremely low as 1.2 gf / cm.

Then, as in the first embodiment, when an experiment was performed to continuously form images on 15,000 sheets using acidic paper, damage to the surface of the photosensitive drum 20 and filming occurred. It was confirmed that the paper dust could be removed without any problem. The image was also good.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

Further, in the above-described embodiment, the paper dust removing means is brought into contact with the photosensitive drum as the visible image carrier. However, the present invention is not limited to this, and as shown in FIG. The paper dust removing means may be brought into contact with an intermediate transfer belt (intermediate transfer member) as a visible image carrier.

The image forming apparatus 200 shown in FIG. 7 is a color copying apparatus for forming a color image using four color toners. Feeder unit 10, photosensitive drum 20, charger 30, laser scanner unit 40, fixing unit 70
1 is common to the apparatus shown in FIG. 1, but as a developing device, a developing device 50 having a yellow toner is used.
The difference is that a developing device 50M having a Y and magenta toner, a developing device 50C having a cyan toner, and a developing device 50Bk having a black toner are provided. Further, in the laser beam printer 1 shown in FIG. 1, the toner image is directly transferred from the photosensitive drum 20 to the sheet. In the apparatus shown in FIG. 7, however, the laser beam printer shown in FIG. It is different from the printer 1. The intermediate transfer belt 201 is, for example, formed by forming a chargeable polyimide into a belt shape. When a voltage is applied while the intermediate transfer belt 201 is pressed against the toner on the photosensitive drum 20, the toner is transferred to the intermediate transfer belt 201 by electrostatic force. afterwards,
When a voltage having a polarity opposite to that of the toner and higher than that of the intermediate transfer belt is applied to the transfer roller 202, the toner is re-transferred to the sheet by the electrostatic force. Thus, in this copying apparatus, it is not the photosensitive drum 20 that directly contacts the paper,
It is an intermediate transfer belt 201. Therefore, in this case,
The nonwoven fabric 81 of the paper dust removing device 80 shown in FIG. 7 is brought into contact with the intermediate transfer belt 201, for example. As a result, paper dust on the intermediate transfer belt and 201 can be reliably removed, and image defects can be prevented.

In each of the embodiments described above, an example was described in which a nonwoven fabric was used as the fiber member attached to the sheet-like member. However, the present invention is not limited to this. , Woven or knitted fabrics can be used.

[0083]

According to the image forming apparatus of the present invention, a fiber member made of any one of a nonwoven fabric, a woven fabric and a knitted fabric is mounted on a base material made of a sheet-shaped member. A paper dust removing means is provided, and the base is positioned so that the fiber member is brought into contact with the visible image carrier. The visible image carrier can be contacted with a low contact pressure, and the paper dust can be reliably removed while reliably preventing the visible image carrier from being damaged or filmed by paper dust.

According to the image forming apparatus of the second aspect,
Since the base material of the paper dust removing means is positioned so as to be elastically deformed in the same direction as the direction in which the visible image is carried and conveyed by the visible image carrier, at least at the time of driving the visible image carrier, Even when the paper dust is accumulated in the contact portion between the fiber member and the visible image carrier, the base material does not hinder the elastic deformation in the above-described direction and can suppress an increase in the pressing force against the paper dust. it can. As a result, the damage or filming can be more reliably prevented.

According to the image forming apparatus of the third aspect,
Between the contact position of the fiber member with the visible image carrier and the transfer position at which the transfer is performed, a paper dust removing unit made of a brush-like member is further provided. The large paper dust is removed by the brush-like member, and the accumulation of the fiber member at the contact position with the visible image carrier can be more reliably prevented. As a result, damage to the visible image carrier can be prevented more reliably. In addition, the accumulation points of the paper dust are dispersed in two places, and the life of the paper dust removing means can be prolonged.

According to the image forming apparatus of the fourth aspect,
Since the base material is formed of a sheet-shaped member made of resin, the fiber-made member comes into contact with the visible image carrier with a very small contact pressure, and damage or filming of the visible image carrier is ensured. Can be prevented.

According to the image forming apparatus of the fifth aspect,
Since the base material is formed of a rubber sheet-shaped member, the fiber member comes into contact with the visible image carrier with an extremely small contact pressure, so that damage or filming of the visible image carrier is ensured. Can be prevented.

According to the image forming apparatus of the sixth aspect,
Since the developer is a polymerized toner obtained by polymerization, it has a smoother surface shape, higher fluidity, and is less likely to adhere to the paper dust removing means than a pulverized toner. Further, since the fluidity is high, rubbing between toners is small, and toner remaining after transfer is reduced. As a result, the toner is hardly captured at the contact position of the fiber member with the visible image carrier, and it is possible to reliably prevent the paper member removing ability of the fiber member from lowering.

According to the seventh aspect of the present invention, since the cleaner-less developing method is used in which the transfer residual developer is collected by the developing device and used for the development again, the paper dust is reliably removed by the paper dust removing means, and the transfer is performed. When collecting the developer into the developing device,
Paper dust can be reliably prevented from being mixed, and image defects such as fog can be reliably prevented from occurring.

According to the image forming apparatus of the present invention,
Since the visible image carrier also serves as the photoconductor, paper dust adhering to the photoconductor can be reliably removed by the paper dust removing unit, and particularly, an image defect at the time of forming a visible image on the photoconductor. Can be reliably prevented.

According to the image forming apparatus of the ninth aspect,
Since the visible image carrier is made of an intermediate transfer member provided to be movable endlessly opposite to the photoreceptor, paper powder adhering to the intermediate transfer member is reliably removed, and the photoreceptor is removed from the intermediate transfer member. The transfer of paper dust to the transfer medium or the transfer of paper dust from the intermediate transfer member to the transfer medium can be reliably prevented, and the occurrence of image defects can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged view around a paper dust removing device in the image forming apparatus of FIG. 1;

FIG. 3 is a perspective view showing a holder in the paper dust removing device of FIG. 2;

FIG. 4 is a cross-sectional view illustrating a periphery of a paper dust removing device according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a periphery of a paper dust removing device according to a third embodiment of the present invention.

FIG. 6 is a perspective view showing a holder in the paper dust removing device of FIG. 5;

FIG. 7 is a sectional view illustrating a schematic configuration of an image forming apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 laser beam printer 20 photosensitive drum 80 paper dust removing device 81 nonwoven fabric 82 urethane sheet 86 brush-like member 89 PET sheet 200 image forming apparatus (color copying apparatus) 201 intermediate transfer belt

Claims (9)

[Claims] An image forming apparatus for developing an electrostatic latent image formed on a photoreceptor with a developer to form a visible image and transferring the visible image to a transfer medium to form an image. A visible image carrier that carries and conveys the visible image to the transfer position; and a paper dust removing unit that removes paper dust on the visible image carrier. On a substrate made of a sheet-like member,
A non-woven fabric, a woven fabric, or a fibrous member made of any one of a knit is attached, and the base member is positioned so as to contact the fibrous member with the visible image carrier. An image forming apparatus comprising: 2. The method according to claim 2, wherein the substrate of the paper dust removing unit is elastically deformed in at least a direction in which the visible image is carried and conveyed by the visible image carrier when the visible image carrier is driven. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is positioned as described above. 3. A paper dust removing means comprising a brush-like member between a contact position of the fiber member with the visible image carrier and a transfer position at which the transfer is performed. The image forming apparatus according to claim 1 or 2, wherein 4. The image forming apparatus according to claim 1, wherein the base member is formed of a resin sheet member. 5. The image forming apparatus according to claim 1, wherein the base member is formed from a rubber sheet member. 6. The method according to claim 1, wherein the developer is a polymerized toner obtained by polymerization.
The image forming apparatus according to claim 1. 7. The image forming apparatus according to claim 1, wherein a cleaner-less developing system is used in which the transfer residual developer is collected by a developing device and is used again for development. apparatus. 8. The image forming apparatus according to claim 1, wherein the photoconductor also serves as the visible image carrier. 9. The image forming apparatus according to claim 1, wherein the visible image carrier is formed of an intermediate transfer member that is provided so as to be movable endlessly so as to face the photoconductor. The image forming apparatus according to claim 1.