JP7183029B2 - Cleaning device, cartridge and image forming device - Google Patents

Description

The present invention relates to a cleaning device, a process cartridge, and an image forming apparatus for removing developer remaining on a photoreceptor after transferring a developer image from the electrophotographic photoreceptor to a recording medium.

2. Description of the Related Art Conventionally, in image forming apparatuses such as copiers and printers, electrostatic recording systems, electrophotographic recording systems, and the like are often used. In this image forming apparatus, an image is formed by forming an electrostatic latent image on a photoreceptor and then transferring the developer image onto a recording material. In such an image forming apparatus, the developer that has not been completely transferred remains on the photoreceptor after transfer, so the developer is usually removed by a cleaning device using an elastic blade or the like.
Further, in recent years, there is a tendency to use developer (toner) having a small average particle size in order to improve image quality such as high definition. However, the small particle size toner cannot be sufficiently removed by a conventional cleaning device using an elastic blade or the like, and the amount of toner slipping between the elastic blade and the image bearing member increases, which may result in poor cleaning.
For this reason, Japanese Patent Laid-Open No. 2002-100003 discloses a configuration in which a charger is arranged between a transfer portion that transfers the developer onto a recording material and a cleaning blade to neutralize residual toner that has not been transferred.

JP-A-06-130870

However, the use of conventional process cartridges has the following problems. In the process cartridge disclosed in Japanese Patent Application Laid-Open No. 2002-200302, a charger is used for neutralizing residual toner that has not been transferred between a transfer portion that transfers developer onto a recording material and a cleaning blade. As a result, the cost is high and a space for a charging device, a high-voltage output device, etc. is required, so that the process cartridge and the image forming apparatus are large in size.
Furthermore, in Patent Document 1, in the static elimination process of the residual toner, only the surface of the toner surface facing the static elimination device is eliminated, and the surface in contact with the photosensitive drum is not sufficiently eliminated. Occur. For this reason, residual toner such as toner with a small particle size has a large electrostatic adhesion force to the drum surface, and the static eliminator cannot remove static electricity from the drum surface. Therefore, the residual toner must be removed with a cleaning blade. is difficult and may result in image defects.

The present invention has been made to solve these problems. That is, even when a toner with a high charge amount or a toner with a small particle size is used, the cleaning blade can effectively remove residual toner and maintain good image formation in a low-cost, small-size configuration. The purpose is to provide an apparatus.

In order to achieve the above object, the cleaning device of the present invention comprises:
a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with a rotatable image carrier that carries a developer image made of developer, and removes the cleaning material from the image carrier. a cleaning member for removing the developer remaining on the image carrier after the developer image is transferred;
a charging member attached to the cleaning frame for charging the image carrier;
A shaft having one end attached to the cleaning frame and the other end contacting the image carrier at a position upstream of the contact position of the cleaning member and the image carrier in the rotational direction of the image carrier . a sheet member;
A cleaning device comprising:
An alternating voltage can be applied to the charging member,
A work function W(D) of the developer and a work function W(S) of the sheet member satisfy the following formula (A).
0≦W(D)−W(S)≦0.23 (A)

Further, in order to achieve the above object, the cartridge of the present invention comprises:
an image carrier that carries a developer image made of developer and is rotatable;
a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with the image carrier, and after the developer image is transferred from the image carrier, the cleaning member contacts the image carrier. a cleaning member for removing residual developer;
a charging member attached to the cleaning frame for charging the image carrier;
A shaft having one end attached to the cleaning frame and the other end contacting the image carrier at a position on the upstream side in the rotation direction of the image carrier relative to the contact position between the cleaning member and the image carrier. a cleaning device having a coating member;
A cartridge that is detachable from the main body of an image forming apparatus,
An alternating voltage can be applied to the charging member,
The work function W(D) of the developer and the work function W(S) of the sheet member are expressed by the following formula (A
) is satisfied.
0≦W(D)−W(S)≦0.23 (A)

Furthermore, in order to achieve the above object, the image forming apparatus of the present invention includes:
an image carrier that carries a developer image made of developer and is rotatable;
a transfer member that transfers the developer image formed on the image carrier carried by the image carrier onto a recording material;
a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with the image carrier, and after the developer image is transferred from the image carrier, the cleaning member contacts the image carrier. a cleaning member for removing residual developer;
a charging member attached to the cleaning frame for charging the image carrier;
A shaft having one end attached to the cleaning frame and the other end contacting the image carrier at a position upstream of the contact position of the cleaning member and the image carrier in the rotational direction of the image carrier . a cleaning device having a coating member;
An image forming apparatus for forming an image on the recording material,
An alternating voltage can be applied to the charging member,
A work function W(D) of the developer and a work function W(S) of the sheet member satisfy the following formula (A).
0≦W(D)−W(S)≦0.23 (A)

In the present invention, even when a toner with a high charge amount or a toner with a small particle size is used, residual toner can be satisfactorily removed by a cleaning blade in a low-cost, small-size configuration, and good image formation can be maintained for a long period of time. be able to.

Schematic cross-sectional view of an image forming apparatus according to the present invention Schematic cross-sectional view of a process cartridge according to the present invention 1 is a perspective view of a charging roller according to the present invention; Explanatory drawing of the amount of penetration and the set angle of the recovery sheet member according to the present invention. Explanatory diagram for calculating the contact pressure of the collection sheet member according to the present invention. Measurement results of the work function of the collection sheet member and the toner according to the present invention Schematic cross-sectional view of a photosensitive drum unit according to the present invention Toner Charge Amount After Passing Collection Sheet Members in Example 1 and Comparative Example 4 Toner Charge Amount After Passing Collection Sheet Members in Examples 1 and 5

BEST MODE FOR CARRYING OUT THE INVENTION A mode for carrying out the present invention will be exemplarily described in detail below based on an embodiment with reference to the drawings. However, the dimensions, materials, shapes and relative arrangement of the components described in this embodiment should be appropriately changed according to the configuration of the device to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments.

Embodiment 1 of the present invention will be described below.

<Example 1>
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment>
<Image forming apparatus>
An image forming process of the image forming apparatus used in the embodiment will be described together with members of the image forming apparatus with reference to FIG. A sheet P as a recording material such as paper is conveyed from the sheet cassette 12 of the image forming apparatus main body A of the image forming apparatus by a conveying roller (not shown), and is synchronized with the sheet conveying. , the photosensitive drum 1 is charged by a charging roller 2 as a charging member. After that, the exposure device 3 selectively exposes the surface of the photosensitive drum 1 to form an electrostatic latent image. The photosensitive drum 1 and the charging roller 2 are rotating bodies, and rotate in the direction of arrow C. As shown in FIG. The exposure device 3 reflects the laser by a polygon mirror and exposes the surface of the photosensitive drum 1 in the main scanning direction and the sub-scanning direction.
A magnetic one-component developer T is supplied from a developer storage chamber 4 by a stirring member 5 to the vicinity of a developer carrying member (hereinafter referred to as a developing sleeve) 6 . The developing sleeve 6 is a hollow rotating body, and a magnet roller (not shown) as a conveying member is arranged inside. The developer T is carried and conveyed on the surface by the magnetic force of this magnet roller. Further, a desired amount of developer T is carried on the surface of the developing sleeve 6 by the developing blade 7 as a thin layer.

Next, by applying a developing bias to the developing sleeve 6, the developer T is supplied to develop a developer image on the photosensitive drum 1 corresponding to the latent image. This image is transferred onto a sheet P as a synchronized recording material by applying a bias to a transfer roller 10 as a rotatable member and as a transfer member. The sheet P is transported to the fixing device 11, where the image is fixed, and is discharged to the paper discharge section 13 at the top of the device by a paper discharge roller (not shown).
Residual toner remains on the photosensitive drum 1 after the transfer is completed. This residual toner is cleaned by an elastic cleaning member (cleaning blade) 8 as cleaning means. Residual toner, which is the developer removed by the cleaning member, is stored as waste toner in a recovery container 9 as a storage section for storing the developer. Waste toner is prevented from leaking out of the collection container 9 by the collection sheet member 14 which also serves as the sealing member 14 .

<Process cartridge>
Next, the overall structure of the process cartridge B according to this embodiment will be described with reference to FIG. The process cartridge B is composed of a photosensitive unit 21 having the photosensitive drum 1 and the like and a developing unit (developing device) 20 having the developing roller 6 and the like, and is detachable from the apparatus body A of the image forming apparatus. The photoreceptor unit 21 is composed of a cleaning device 22 for removing residual toner remaining on the photoreceptor drum 1 and the photoreceptor drum 1 . The cleaning device 22 has at least a cleaning member 8 , a collection sheet member (sheet member) 14 and a collection container (accommodation container) 9 . In this embodiment, a charging roller 2 is also provided in addition to that. In the cleaning device 22 , the toner remaining on the surface of the photosensitive drum 1 is removed by contacting the cleaning member 8 with the photosensitive drum 1 .

The photosensitive drum 1 is rotatably attached to the photosensitive unit 21 via a bearing (not shown). The photosensitive drum 1 receives a driving force from a driving motor (not shown), and is rotationally driven in the direction of arrow C according to the image forming operation. Further, the photoreceptor unit 21 has a charging roller 2 , a cleaning member 8 , a collection sheet member 14 and a collection container 9 . The charging roller 2 , the cleaning member 8 and the recovery sheet member 14 are arranged so as to contact the photosensitive drum 1 .
The photosensitive drum 1 has a diameter of 24 mm and is composed of a charge transport layer, a charge generation layer, an undercoat layer, and an aluminum cylinder. The rotational speed of the photosensitive drum 1 is 200 mm/sec.

FIG. 3 shows a perspective view of the charging roller 2 according to this embodiment. The charging roller 2 has a structure in which a shaft portion 2a made of a metal core bar is provided in the center, a resistance adjustment layer 2b1 is provided on the outer side of the shaft portion 2a, and a surface layer 2b2 is provided as the outermost layer. The shaft portion 2a is made of a highly rigid and conductive metal ^such as stainless steel or aluminum having a diameter of 8 ^to 20 mm. It may be made of a conductive resin or the like having high rigidity with a size of 1 cm or less.

The resistance adjusting layer 2b1 preferably has a volume resistivity of 1×10 ⁵ Ω·cm to 1×10 ⁹ Ω·cm and a thickness of about 1 to 2 mm.
The surface layer 2b2 preferably has a volume resistivity of 1×10 ⁶ Ω·cm to 1×10 ¹² Ω·cm and a thickness of about 10 μm. The volume resistivity of the surface layer is preferably higher than the electrical resistivity of the resistance adjusting layer 2b1. Although the charging roller 2 has a two-layer structure consisting of the resistance adjusting layer 2b1 and the surface layer, it is not limited to this structure, and may have a single layer structure or a three-layer structure.
The resistance adjusting layer 2b1 is formed by extruding or injection molding a resin composition to provide a rubber material such as foamed urethane rubber, silicon rubber, hydrin rubber, etc. on the peripheral surface of the core metal 2a. In order to prevent the resistance adjustment layer 2b1 from deforming with time and changing the gap between the photoreceptor 1 and the charging roller 2, the resistance adjustment layer 2b1 should have a JIS-D hardness of 45 degrees or more.
The thermoplastic resin used for the surface layer 2b2 is not particularly limited as long as it can maintain the JIS-D hardness after molding. However, the use of general-purpose resins such as polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), polystyrene (PS) and copolymers thereof (AS, ABS, etc.) facilitates molding. preferable.
Conductive materials such as polymeric ionic conductive agents, carbon black, and metal powders can be used to adjust electrical resistance.

The charging roller 2 is connected to a power supply section 17 as voltage applying means, and is configured to be able to apply a predetermined voltage. The voltage used in the present invention is an alternating voltage. Preferably, it is a DC voltage superimposed with an alternating current (AC) voltage. Although the AC voltage is a sine wave in this embodiment, the AC voltage is not limited to this, and may be a rectangular wave or the like. By applying the AC voltage, the surface of the photoreceptor 1 can be charged more uniformly. In this embodiment, the AC voltage is superimposed on the DC voltage.
The charging roller 2 is urged by an urging spring (not shown) to roll on the surface of the photosensitive drum 1 . A charging voltage obtained by superimposing an AC voltage and a DC voltage is applied to the charging roller 2 from a power supply unit 17 of the apparatus main body, and the surface of the photosensitive drum 1 is charged to a uniform potential. Specifically, a charging voltage in which an AC voltage having a peak-to-peak voltage value Vpp of 1500 V is superimposed on a DC voltage of -400 V is applied to the charging roller 2, thereby reducing the surface of the photosensitive drum 1 to -400 V. It can be uniformly charged. In the embodiments, the peak value of the peak-to-peak voltage applied to the charging roller 2 is the amplitude of a sine wave (Peak to Peak), but it also represents the amplitude (Peak to Peak) when a rectangular wave is employed. and The charging roller 2 is urged by an urging spring (not shown) to roll on the surface of the photosensitive drum 1 to charge the photosensitive drum 1, and is a contact type charging device. Compared to the conventional corona charging method, this contact-type charging device generates an extremely small amount of discharge products, lowers the cost of the power supply due to the low applied voltage, and facilitates the design of electrical insulation. has the advantage of Of course, the problems caused by ozone, nitrogen oxides, etc. are also reduced.

In this embodiment, the thickness of the metal support constituting the cleaning member 8 is 1.2 mm to 2.0 mm, and the hardness of the polyurethane rubber is 60° to 80° (Wallace hardness). As the polyurethane rubber, it is also possible to use a tip hardened blade obtained by hardening the portion of the polyurethane rubber that contacts the photosensitive drum. The cleaning member 8 removes toner remaining on the photosensitive drum 1 after the toner is transferred from the photosensitive drum 1 to the recording material P. As shown in FIG. The toner removed by the cleaning member 8 is stored in the collection container 9 . One end of the cleaning member 8 is a fixed end that is fixed to the frame 15 , and the other end of the cleaning member 8 is a free end that contacts the photosensitive drum 1 . A free end (tip) of the cleaning member 8 extends from the downstream side to the upstream side in the rotational direction of the photosensitive drum 1 and contacts the photosensitive drum 1 . That is, the direction in which the cleaning member 8 extends from the fixed end toward the free end is opposite to the rotating direction of the photosensitive drum 1 in the area where the free end of the cleaning member 8 abuts.

<Collection sheet member>
Next, the recovery sheet member 14 will be described. As shown in FIG. 2, the collection sheet member 14 is a constituent element of a photoreceptor unit 21 having a photosensitive drum 1, a charging roller 2, a cleaning member 8, and a collection container 9. As shown in FIG. The collection sheet member 14 is arranged upstream of the cleaning member 8 in the rotational direction of the photosensitive drum 1 . After the toner image has been transferred to the recording material P, the toner remaining on the photosensitive drum 1 is removed by the cleaning member 8 , and the removed toner is accommodated in the recovery container 9 . The collection sheet member 14 prevents the contained toner from leaking out of the collection container 9 .

In this embodiment, the collection sheet member 14 is adhered to an adhesive surface provided on a frame (cleaning frame) 15 constituting the collection container 9 by double-sided tape, laser welding, or the like. Here, the collection sheet member 14 extends in the axial direction of the rotation center of the photosensitive drum 1 and is adhered to the frame so as to contact the photosensitive drum 1 . One end of the collection sheet member 14 is a fixed end that is fixed to the frame 15 , and the other end of the collection sheet member 14 is a free end that contacts the photosensitive drum 1 . In a state in which the recovery sheet member 14 is adhered to the frame 15 , the free end side (front end side) of the recovery sheet member 14 extends from the upstream side to the downstream side in the rotation direction of the photosensitive drum 1 and extends along the photosensitive drum 1 . abutting. That is, the direction extending from the fixed end of the collection sheet member 14 toward the free end is substantially the same as the rotation direction of the photosensitive drum 1 in the area where the free end of the collection sheet member 14 abuts. Further, the collection sheet member 14 contacts the outer peripheral surface of the photosensitive drum 1 upstream of the contact position of the cleaning member 8 with respect to the photosensitive drum 1 in the rotational direction of the photosensitive drum 1 . The collection sheet member 14 closes the gap between the photosensitive drum 1 and the frame 15 so that the toner stored in the collection container 9 does not leak out from the gap between the photosensitive drum 1 and the frame.

The cleaning member 8 contacts the photosensitive drum 1 in the counter direction of the rotation direction (direction C) of the photosensitive drum 1 , and the collection sheet member 14 contacts in the rotation direction of the photosensitive drum 1 . Since the facing space between the cleaning member 8 and the collection sheet member 14 is connected to the inside of the collection container 9, the toner removed from the photosensitive drum 1 is collected from the gap between the photosensitive drum 1 and the frame 15. It is stored in the collection container 9 without leaking out of the container 9. - 特許庁

In Example 1, the following materials are used for the recovery sheet member 14 .
Material: PPS (polyphenylene sulfide) sheet Thickness: 38 μm
Work function: 5.80 eV
Young's modulus: 3000 N/m ²
Poisson's ratio: 0.38
In addition, the cleaning frame 15 is adhered to the cleaning frame 15 by laser welding so that the condition of contact with the photosensitive drum 1 is as follows.
Penetration amount: 3.4 [μm]
Setting angle: 28.6 [°]
Deflection amount δ: 1.24 [mm]
Contact pressure: 8.72×10 ⁻⁴ [N/mm]

Here, the amount of penetration and the set angle will be described with reference to FIG.
α shown in FIG. 4 is defined as the penetration amount [mm], and β is defined as the set angle [°]. α represents the amount by which the recovery sheet member 14 intrudes into the outer shape of the photosensitive drum 1 when the photosensitive drum 1 is not present. That is, it is the distance from the surface of the photosensitive drum 1 to the free end (tip) of the collection sheet member 14 when it is assumed that the photosensitive drum 1 is not present. The recovery sheet member 14 assuming that the photosensitive drum 1 is not present is indicated as a recovery sheet member 14'. Also, the set angle β is between the tangent line on the photosensitive drum 1 at the intersection of the outer shape of the photosensitive drum and the collecting sheet member 14′ in the absence of the photosensitive drum 1 and the collecting sheet member 14′ in the absence of the photosensitive drum 1. represents the angle formed by Here, a straight line S3 extending perpendicularly to a straight line S2 extending along the collecting sheet member 14' from the fixed end to the free end of the collecting sheet member 14' toward the free end thereof, and the straight line S3 starting from the point Q and the line between the photosensitive drum 1 and the Let M be the distance from the center point (rotational center position) O. A point Q is an arbitrary point on the edge portion of the free end (tip) of the collection sheet member 14 ′ and is arranged on the center point O side of the photosensitive drum 1 . Further, the distance between a straight line S4 starting at a point Q forming an angle of 45° in the direction toward the collection container 9 with respect to a straight line S3 perpendicular to the straight line S2 starting at the point Q and the point O is N. and By measuring these distances M and N and applying them to the following equations, it is possible to calculate the penetration amount α and the set angle β. Here, r represents the radius [mm] of the photosensitive drum.

Also, a method of calculating the contact pressure will be described with reference to FIG.
5, the collection sheet member 14 is flexed by contacting the photosensitive drum 1 with the free end (tip) of the collection sheet member 14 adhesively fixed to the seat surface 16. As shown in FIG. The calculated value of the contact pressure P [N] of a unit length (1 mm) in the longitudinal direction of a very thin collection sheet member with respect to the photosensitive drum 1, such as that used in the image forming apparatus A, is 1.32×10 ⁻⁵ or more. It is preferably 1.74×10 ⁻² or less. The calculated value of the contact pressure P[N] is calculated by calculating the consideration conditions described later in the following formula (3) using a general formula for the load and deflection applied to the cantilever spring.
Here, the amount of deflection of the collection sheet member 14 is δ [mm], and the distance (free length) from the fixed end of the collection sheet member 14 to the contact nip between the photosensitive drum 1 and the free end of the collection sheet member 14 is L. [mm], and the thickness of the collection sheet member 14 is h [mm]. Here, E=Young's modulus [N/mm ² ] of the collection sheet member 14, and ν=Poisson's ratio of the collection sheet member 14. FIG.
P=δEh ³ /{4L ³ (1−ν ² )} (3)

In this embodiment, other embodiments, and comparative examples, almost the tip of the recovery sheet member 14 is in contact with the photosensitive drum 1 . Therefore, the distance L from the fixed end of the collecting sheet member 14 to the contact nip between the photosensitive drum 1 and the free end of the collecting sheet member 14 is approximated by the distance from the fixed end to the free end of the collecting sheet member 14. I am using The amount of deflection δ of the collecting sheet member 14 is determined by the contact portion of the free end of the collecting sheet member 14 with the photosensitive drum 1 and the edge portion of the free end of the collecting sheet member 14A on the side of the center point O of the photosensitive drum 1. is approximated by the distance between

The present invention was investigated in the following range.
Radius of photosensitive drum = 12 [mm],
M = 1.69 to 3.06 [mm]
N = 5.31 to 6.30 [mm]
Penetration amount δ = 2.62 to 4.13 [mm]
Thickness of collection sheet member h = 10 to 100 [μm]
Free length L of collection sheet member = 3.39 to 4.79 [mm]

<Toner>
In the toner used in this embodiment, the binder resin is a styrene resin, and the release agent is an ester compound. The ester compound moderately acts on the styrenic resin to soften the binder resin. Since the ester compound has a high sharp-melt property, the ester compound that is not compatible with the styrene-based resin melts quickly in the fixing area. Further, crystalline polyester is finely dispersed in the toner in order to improve the low-temperature fixability of the toner. By uniformly dispersing the highly crystalline polyester in the toner, it is possible to rapidly plasticize the entire toner particles. In order to finely disperse the crystalline polyester, it is important to form a large amount of crystal nuclei of the ester compound inside the toner particles. For this purpose, it is necessary to suppress the crystallinity of the ester compound to some extent. When the composition of the ester compound has a distribution, the crystallization rate of the ester compound is lowered and a large amount of crystal nuclei are likely to be generated as compared with an ester compound having a single composition. Therefore, it is preferable that the composition of the ester compound has a distribution.

Also, in order to modify the surface properties of the toner, it is possible to form an inorganic substance on the surface of the toner and use it. Examples of inorganic substances formed on the toner surface include silica, alumina, titanium oxide, aluminum oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, and clay. can do. Furthermore, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. can also be used. . Further, the inorganic substance formed on the toner surface is preferably formed in the form of fine inorganic particles by adhering to the toner surface and used. In the present invention, it is preferable to use one of the above inorganic substances alone or two or more of them in combination.

In this embodiment, negatively chargeable magnetic toner produced by suspension polymerization and having a volume average particle diameter of about 8 μm is used. Although the toner produced by the suspension polymerization method was used in this embodiment, the present invention is not limited to this. For example, it may be a toner manufactured using a pulverization method or another polymerization method such as an emulsion polymerization method. Here, the volume average particle diameter of the toner is measured by a precision particle size distribution measuring device Multisizer 3 manufactured by Beckman Coulter, Inc.
In this embodiment, silicon oxide particles and titanium oxide particles are uniformly adhered to the surface of the toner and used as inorganic substances formed on the surface of the toner. In this embodiment, silicon oxide particles having a number average particle diameter of about 20 nm are added to about 1.5% of the toner weight, silicon oxide particles having a number average particle diameter of about 50 nm are added to about 0.8% of the toner weight, and titanium oxide is used. About 0.1% of the toner weight of the particles is used.

The work function of the toner used in this embodiment is 6.03 eV. (Details of the measurement method will be described later.) The material of the toner matrix and the work function of the toner used in other examples will be described for each example.

Next, Comparative Examples 1 to 3 for confirming the effect of Example 1, Example 2 of the present invention, and Examples 3 to 5 for increasing the effect of the present invention will be described. The configurations of Comparative Examples 1 to 3 and Examples 2 to 4 are practically the same as those of the present example except for the points specifically described below. In Comparative Examples 1 to 3 and Examples 2 to 5, the same reference numerals are given to elements that have functions or have the same functions as those of the present embodiment.

<Comparative Example 1>
The difference between this comparative example and the first embodiment is that the bias power supply (high voltage power supply) applied to the charging roller is changed to a DC voltage. In this comparative example, a DC voltage of −900 V is applied to the charging roller to charge the surface of the photosensitive drum to −400 V as in the first embodiment.

<Comparative Example 2>
This comparative example differs from the first example in that the material of the collection sheet member 14 and the material of the toner base are changed. In this comparative example, the following materials are used for the collection sheet member and the toner.
・Collection sheet member Material: PET sheet (manufactured by Toray Industries, Inc.: Lumirror (registered trademark))
Thickness: 38 [μm]
Work function: 5.33 [eV]
Flexural modulus: 2000 [N/m ² ]
Poisson's ratio: 0.21
Further, contact conditions of the recovery sheet member 14 with respect to the photosensitive drum 1 are shown below. The collection sheet member 14 is adhered to the cleaning frame 15 by laser welding.
Penetration amount: 3.4 [μm]
Setting angle: 28.6 [°]
Deflection amount δ: 1.24 [mm]
Contact pressure: 5.20×10 ⁻⁴ [N/mm]

Toner In the magnetic toner of Comparative Example 2, the binder resin is a styrene-based resin and the release agent is an ester compound. A different point from Example 1 is that no crystalline polyester is blended. Since the material used for the toner matrix is different, the work function is different. The work function of the toner of Comparative Example 1 is 5.65 eV.

<Comparative Example 3>
The difference between this comparative example and the first example is that the material of the collection sheet member 14 is changed.
・Collection sheet member Material: PET sheet (manufactured by Toray Industries, Inc.: Lumirror (registered trademark))
Thickness: 38 [μm]
Work function: 5.33 [eV]
Flexural modulus: 2000 [N/m ² ]
Poisson's ratio: 0.21
Further, contact conditions of the recovery sheet member 14 with respect to the photosensitive drum 1 are shown below. The recovery sheet member 14 is adhered to the cleaning frame by laser welding.
Penetration amount: 3.4 [μm]
Setting angle: 28.6 [°]
Deflection amount δ: 1.24 [mm]
Contact pressure: 5.20×10 ⁻⁴ [N/mm]

<Comparative Example 4>
This comparative example differs from Example 1 in that the conditions of the toner base are changed to the same conditions as in Comparative Example 2. FIG.

<Example 2>
The second embodiment differs from the first embodiment in that the material of the collection sheet member 14 is changed.
・Collection sheet member Material: PTFE (polytetrafluoroethylene) sheet (Teflon (registered trademark))
Thickness: 50 [μm]
Work function: 6.0 [eV]
Flexural modulus: 560 [N/m ² ]
Poisson's ratio: 0.46
Further, contact conditions of the recovery sheet member 14 with respect to the photosensitive drum 1 are shown below. The recovery sheet member 14 is adhered to the cleaning frame by laser welding.
Penetration amount: 3.4 [μm]
Setting angle: 28.6 [°]
Deflection amount δ: 1.24 [mm]
Contact pressure: 4.02×10 ⁻⁴ [N/mm]

<Example 3>
The third embodiment differs from the first embodiment in the method of attaching the collection sheet member 14 to the collection container 9 . In this embodiment, a double-faced tape is applied to the cleaning frame, and the recovery sheet member is placed thereon to fix the recovery sheet to the cleaning frame. The contact conditions of the collection sheet member 14 with respect to the photosensitive drum 1 are shown below.
Penetration amount: 4.9 [μm]
Setting angle: 37.3 [°]
Deflection amount δ: 2.24 [mm]
Contact pressure: 1.57×10 ⁻³ [N/mm]

<Example 4>
The fourth embodiment differs from the first embodiment in that the thickness of the collection sheet member is changed. In this embodiment, a PPS sheet having a thickness of 60 μm is adhered to the cleaning frame by laser welding so that the collection sheet member 14 contacts the photosensitive drum 1 under the following conditions.
Penetration amount: 3.4 [μm]
Setting angle: 28.7 [°]
Deflection amount δ: 1.24 [mm]
Contact pressure: 1.99×10 ⁻³ [N/mm]

<Example 5>
This embodiment differs from the first embodiment in that the peak-to-peak voltage value Vpp during non-image formation is set to 1700 V, which is higher than that during image formation.

<Combination of collection sheet member and toner>
Next, the combination of the AC charging method, the recovery sheet member, and the toner, which is the point of the invention, will be described. The inventors of the present invention have found that the size relationship between the work function (details of the measuring method will be described later) between the collection sheet member 14 and the toner greatly affects the cleaning performance of the toner remaining on the photosensitive drum. Furthermore, the inventors have found that the use of an AC charging method can maintain good cleaning performance over a long period of time. The evaluation method and evaluation results will be described in detail below.

<Evaluation method for each example and comparative example>
Work function measurement In the present invention, focusing on the positional relationship in the electrification series between the collection sheet member and the toner, the three types of collection sheet members 14 used in the experiment and the two types of toner A and B were measured by the following measurement method. Evaluated by the measured work function.
Here, the work function (Φ) is the energy required to extract electrons from the substance. If the work function difference between the two members is large, the electric field generated by triboelectrification between the two members will be large, and if the work function difference between the two members is small, The electric field generated by triboelectrification becomes smaller.

- Measurement method of work function The work function can be measured by the following measurement method. It is quantified as the energy (eV) for extracting electrons from the substance, and can evaluate the charge polarity of the collection sheet member and the toner.
The work function (Φ) is measured using a surface analyzer (AC-2, manufactured by Riken Keiki Co., Ltd.). In the surface analysis device, a deuterium lamp is used, the irradiation light intensity is set appropriately, monochromatic light is selected with a spectroscope, the spot size is 4 [mm] × 4 [mm], and the energy operation range is 3.4 to 6.2. The sample is irradiated with [eV] and a measurement time of 10 [sec/1 point]. A work function is obtained by detecting photoelectrons emitted from the surface of the sample and performing arithmetic processing using work function meter software incorporated in the surface analysis apparatus. The work function is measured with a repeatability (standard deviation) of 0.02 [eV].
The work functions of the collection sheet member 14 and the toner were measured before image formation. In addition, the collection sheet member 14 was measured after dust on the surface was removed by air blowing.
In order to ensure data reproducibility, a measurement sample was prepared by leaving it for 24 hours under conditions of a working temperature of 25° C. and a humidity of 55% RH after the above image formation.
When measuring a sheet-shaped sample such as the collection sheet member 14, the measurement light is irradiated with a spot of 4 [mm] x 4 [mm] as described above, so the sample piece is at least 1 [cm]. ] x 1 [cm], fixed on a sample table, and measured.

Similarly, when measuring a powder sample such as toner, the sample should be placed in a shallow dish-shaped container with a size of at least 1 [cm] x 1 [cm], and the toner should be arranged smoothly without gaps. Measured fixed to a table.
In the above surface analysis, when the excitation energy of monochromatic light is scanned from low to high, photon emission starts at a certain energy value [eV], and this energy threshold is taken as the work function [eV]. FIG. 6 shows an example of a chart obtained using a surface analysis apparatus for recovered sheet members. ◯ in the figure indicates the measurement results, and the dashed line is an approximation line connecting the ◯. In FIG. 6, the horizontal axis is photon energy [eV], and the vertical axis is EmissionYield [cps0.5] (the 0.5th power of the photoelectron yield per unit photon). From FIG. 6, a constant slope [EmissionYield/photon energy] is obtained. In the case of FIG. 6, the work function is indicated by the excitation energy [eV] at the inflection point of the dashed line ((B) in the figure). In FIG. 6, it is 5.33 [eV].

Cleaning Evaluation In this evaluation, image defects such as streaks caused by toner slipping through the cleaning blade 8 on the recording material P were evaluated.
・Cleaning evaluation (initial)
In this evaluation, first, the developing unit of the process cartridge B is filled with toner. After the process cartridge B was left in an environment of 7.5° C. and 30% RH for 24 hours, a recorded image with an image ratio of 4% was formed by a plurality of horizontal lines (lines along the axial direction of the photosensitive drum). is continuously printed on 200 sheets of A4 size paper. The presence or absence of streak-like image defects was checked for all 200 printed sheets.

・Cleaning evaluation (after endurance)
This evaluation was performed after the cleaning evaluation (initial stage) described above. A recording image with an image ratio of 4% formed by a plurality of horizontal lines (lines along the axial direction of the photosensitive drum) is intermittently printed on 10,000 sheets of A4 size paper. Here, "intermittently" means a printing method in which the printing operation of the process cartridge is temporarily stopped after printing a predetermined number of sheets, and then the printing operation is resumed. After printing 10,000 sheets, a recorded image with an image ratio of 4% formed by multiple horizontal lines is printed continuously on 200 sheets of A4 size paper. I checked the presence or absence of Table 1 shows the results of this evaluation.
In addition, evaluation criteria for cleaning evaluation are shown below.
1: No streak-like image defects are recognized.
2: A streak-like image defect is recognized on 1 or more and less than 10 sheets.
3: Image defects such as streaks are recognized on 10 sheets or more and less than 50 sheets.
4: Image defects such as streaks are recognized on 50 or more sheets.

Table 1 shows the measurement results of the work functions of the collecting sheet member and the toner in Examples 1 to 4 and Comparative Examples 1 to 4, and the contact pressure and cleaning evaluation results of the collecting sheet member.

<Superiority of the present invention over comparative technology>
The superiority of the present invention will be described by comparing each example with a comparative technique.
First, the superiority of the present invention over Comparative Example 1, which is the prior art, will be described. As a result of extensive studies, the inventors of the present invention have found that by using an AC charging method in which an AC voltage is applied to the charging roller 2, it is possible to keep the residual toner from becoming strongly negative due to the recovery sheet member 14 over a long period of use. I found out what I can do. It should be noted that the strong negative of the residual toner means that the residual toner is excessively charged.

The above mechanism will be explained by comparing Example 1 and Comparative Example 1. FIG. In Example 1, AC voltage and DC voltage are superimposed and applied to the charging roller 2 (AC charging method). On the other hand, Comparative Example 1 differs in that only a DC voltage is applied to the charging roller 2 (DC charging method). Since Example 1 and Comparative Example 1 use the same toner A and the same PPS as the collection sheet member, the value of work function difference is the same, 0.23 eV. As a result of the cleaning evaluation, in Example 1, the occurrence of vertical streak images was slight at the initial stage, and the slight level was maintained until after the endurance. On the other hand, in Comparative Example 1, vertical streak images occurred at a slight level at the initial stage, but at a bad level after the endurance test. It is considered that the reason for this is that the charging method affects the strong negative suppressing effect. It is conceivable that the toner and the external additive remain in the contact portion between the collecting sheet member 14 and the photosensitive drum 1 due to the long-term printing operation. When actually observing the process cartridge B after the evaluation in Comparative Example 1, it was found that toner and external additives adhered to the surface of the collection sheet member 14 . For this reason, in Comparative Example 1, toner and external additives adhere to the surface of the collection sheet member 14 due to long-term printing operation. It is considered that a vertical streak image of a bad level was generated in the evaluation.

On the other hand, in Example 1, the reason why the vertical streak image is maintained at a slight level even after the endurance test will be described below.
FIG. 7 shows a schematic diagram of the charging roller 2 and the photosensitive drum 1 in the image forming apparatus of the first embodiment. Example 1 is an AC charging system. Therefore, in the image forming apparatus, between the metal core 2a of the charging roller 2 connected to the AC voltage power supply 17a included in the power supply section 17 as voltage applying means and the metal base tube 100 of the photosensitive drum 1 connected to the ground. , an alternating electric field is generated by the alternating voltage. An alternating electric field causes electrostatic attraction between the charging roller 2 and the photosensitive drum 1, and the force changes with the cycle of the alternating electric field. Due to this changing electrostatic attraction, the charging roller 2 made of an elastic material vibrates minutely. Since the charging roller 2 is in contact with the photosensitive drum 1 by spring pressure (not shown), the vibration of the charging roller 2 is transmitted to the photosensitive drum 1, and the photosensitive drum 1 also slightly vibrates. In other words, the photosensitive drum 1 slightly vibrates in the first embodiment, which uses the AC charging method. It is believed that this makes it easier for the toner to roll at the contact portion between the photosensitive drum 1 and the recovery sheet member 14, thereby suppressing the retention of the toner.

When actually observing the surface of the collection sheet member after evaluation in Example 1 and Comparative Example 1, it was found that more toner and external additives adhered to the surface of the collection sheet 14 in Comparative Example 1 than in Example 1. rice field. For this reason as well, in the first embodiment, it is possible to prevent the toner and the external additive from continuously adhering to the surface of the collection sheet member 14, and to prevent the effect of the collection sheet member 14 of suppressing the residual toner from becoming strongly negative. can. As a result, the same image level as the initial image level can be maintained even after endurance. Here, the vibration of the photosensitive drum 1 is very small, and the cleaning blade 8 is in contact with the photosensitive drum 1 with a sufficiently high contact pressure. 1 does not cause air gaps. Therefore, the vibration of the photosensitive drum 1 by the AC charging method can cause the toner to roll at the contact portion between the collection sheet member 14 and the photosensitive drum 1, while the contact portion between the cleaning blade 8 and the photosensitive drum 1 can cause the toner to roll. Toner slipping through does not occur in .

Next, the combination of the collection sheet member 14 and the toner, which is the point of the invention, will be described. The present inventors have found that the size relationship between the work function (details of the measuring method will be described later) between the collection sheet member and the toner greatly affects the cleaning performance of the toner remaining on the photosensitive drum. The above mechanism will be explained by comparing Examples 1 and 2 with Comparative Examples 2 and 3.
Comparative Example 2 is an example in which PET is used as the material of the collection sheet member 14 and toner B is used as the toner. In Comparative Example 2, a large number of vertical streak images occurred due to poor cleaning in the cleaning evaluation. This is because residual toner on the photosensitive drum rubs against the collecting sheet member 14 when it passes through the contact portion between the collecting sheet member 14 and the photosensitive drum 1, thereby becoming a strong negative image. Since a strong electrostatic adhesion force acts between the strongly negative residual toner and the photosensitive drum 1 , it becomes difficult to scrape and remove the residual toner from the photosensitive drum 1 with the cleaning blade 8 . Therefore, particularly in this embodiment, in which the toner has a high degree of circularity and uses polymerized toner, the toner easily slips through the cleaning blade 8, and the slipped toner remains on the photosensitive drum, and is deposited on the recording paper during subsequent image formation. Vertical streaks appear on the transferred image.
Comparative Example 3 is an example in which toner A is used instead of the toner in Comparative Example 2. FIG. As a result of the cleaning evaluation, compared with Comparative Example 2, more vertical streak images occurred.

On the other hand, in Example 1, PPS is used as the material of the collection sheet member 14 and toner A is used. In Example 1, as a result of the cleaning evaluation, no vertical streak image occurred. This is because the remaining toner on the photosensitive drum is prevented from becoming strongly negative due to rubbing of the residual toner on the contact portion between the collection sheet member 14 and the photosensitive drum 1, and the charge amount is maintained at an appropriate level. is the factor. This is probably because the electrostatic adhesion force between the photosensitive drum 1 and the residual toner is low and the residual toner can be easily removed by the cleaning blade 8 . FIG. 8 shows a comparison of the toner charge amount before and after passing through the collection sheet between Comparative Example 3 and Example 1. As shown in FIG. From FIG. 8, in Comparative Example 3, the toner charge amount after the residual toner passed through the collecting sheet member 14 greatly increased, whereas in Example 1, the toner charge amount after passing through the collecting sheet member 14 It can be seen that the increase in

The mechanism that is considered to have caused the difference in the amount of increase in the charge amount of the residual toner due to the collecting sheet member between Example 1 and Comparative Examples 2 and 3 will be described below.

As a result of extensive studies, the inventors of the present invention have found that the difference between the work function of the toner and the work function of the collection sheet member 14 (work function difference) is greater than the charge amount increase of the residual toner due to passing through the collection sheet member 14. It was found that It is considered that when resin materials having different work functions are rubbed, a negative charge moves from a material with a lower work function to a material with a higher work function. The low work function material is thereby positively charged and the high work function material is negatively charged.
In Comparative Example 2, as shown in Table 1, the work function difference ((work function of toner)-(work function of collection sheet member)) is 0.32 eV. Moreover, the work function difference of Comparative Example 3 is 0.7 eV. In Comparative Examples 2 and 3, since the collection sheet member and the toner have a large work function difference, it is considered that the residual toner becomes strongly negative. In addition, the reason why comparative example 3 has more vertical streak images than comparative example 2 is considered to be the combination of the collection sheet member and the toner having a work function difference larger than that of comparative example 2. FIG. On the other hand, in Example 1, the combination of the collection sheet member and the toner was PPS and toner A, and the work function difference was as small as 0.23 eV. presumably did not occur.

Further, Example 2 is an example in which PTFE is used as the material of the collecting sheet member 14 and toner A is used as the toner. The work function difference is a very small value of 0.03 eV, and no vertical streak image occurs in the cleaning evaluation.

Next, Comparative Example 4 will be described.
Comparative Example 4 is an example in which PPS is used as the material of the collection sheet member 14 and Toner B is used as the toner. In the cleaning evaluation, many vertical streak images are generated. The reason for this is considered to be that the work function difference is a negative value. Unlike Examples 1 and 2 and Comparative Examples 1 to 3, the work function value of the collection sheet member 14 is greater than the work function value of the toner, so the collection sheet is negatively charged and the toner is positively charged. It is thought that there is a trend. The residual toner rubbed against the collection sheet member 14 has a smaller charge amount than before rubbing, and the electrostatic adhesion force between the photosensitive drum 1 and the residual toner becomes too small. It is thought that it becomes easier to adhere to the collection sheet member 14 away from. As a result, the toner that adheres to the collection sheet member 14 and stagnates at the contact portion between the collection sheet member 14 and the photosensitive drum 2 is generated, so that the residual toner on the photosensitive drum 1 rubs against the collection sheet member 14 . It is thought that the effect of suppressing strong negative conversion is lost. For the above reasons, it is preferable to suppress the residual toner from becoming strongly negative, and ideally, it is preferable to charge the toner to a weak charge amount. However, it is not preferable to reduce the charge amount to a value close to zero. As a condition for realizing this, the work function difference between the toner and the collecting sheet member 14 is preferably 0 eV or more and 0.23 eV or less.

According to the present invention, by using a combination in which the work function difference between the toner and the collection sheet member 14, that is, the value of (the work function of the toner)-(the work function of the collection sheet member) is 0 eV or more and 0.23 eV or less. , it is possible to suppress the residual toner from becoming strongly negative. Furthermore, by using the AC charging method, it is possible to maintain the effect of suppressing strong negative image formation for a long period of time. As a result, the remaining toner can be easily removed by the cleaning blade 8, and the occurrence of vertical streak images can be prevented for a long period of time.

Examples for making the effects of the present invention more remarkable will be described below.
Examples 3 and 4 will be described as examples in which the effect is more remarkable than that of the first example.
In Example 3, compared with Example 1, the result of the cleaning evaluation was even better, and no vertical streak image occurred. This is probably because the contact pressure of the collection sheet member 14 against the photosensitive drum 1 was increased by the thickness of the double-sided tape of 1 mm by adhering the collection sheet member 14 to the cleaning frame with the double-sided tape. That is, by increasing the contact pressure of the collection sheet member 14 against the photosensitive drum 1, the residual toner layer is made uniform at the contact nip between the collection sheet member and the photosensitive drum, and the toner rubs against the collection sheet member. Opportunities are likely to increase. It is believed that this further promoted the effect of suppressing the toner from becoming strongly negative.

Also, in Example 4, the result of the cleaning evaluation is even better than in Example 1, and vertical streak images do not occur. The reason for this is thought to be that the use of a collection sheet member having a thickness of 50 μm increased the contact pressure on the photosensitive drum. Further, by setting the thickness of the collection sheet member 14 to 50 μm, waviness when the collection sheet member 14 is attached to the seating surface of the cleaning frame 15 is reduced, and a high contact pressure against the photosensitive drum 1 can be applied in the longitudinal direction. can be formed in the same way. The thickness of the recovery sheet member 14 may be 50 μm or more and 100 μm or less. This is because if the collection sheet member 14 that is too thick is used, the photosensitive drum 1 may be scratched. FIG. 9 shows the toner charge amount distribution after the residual toner passes through the collection sheet member 14 in Examples 1 and 4. As shown in FIG. As shown in FIG. 9, in Example 4, the contact pressure of the collection sheet member 14 against the photosensitive drum 1 was increased in the same manner as in Example 3, thereby promoting the effect of suppressing the toner from becoming strongly negative. I understand.

In addition, Example 5 will be described as another embodiment of the present invention.
Example 5 differs from Example 1 in that an AC peak-to-peak voltage Vpp=1700 V, which is higher than that during image formation, is applied during non-image formation. As a result of cleaning evaluation, the image level after running was better than that of Example 1. This is because increasing the peak-to-peak voltage Vpp prevents the toner and the external additive from continuously adhering to the surface of the collection sheet member. This embodiment uses the optimum Vpp value for uniform charging of the photosensitive drum during image formation, and is effective in cleaning the collection sheet member 14 when no toner remains on the photosensitive drum during non-image formation. , using large Vpp values. The greater the peak voltage Vpp, the greater the vibration of the photosensitive drum 1, and the greater the rolling of the toner at the contact portion between the collection sheet member and the photosensitive drum. As a result, toner adhesion to the surface of the collection sheet member 14 is suppressed, and the effect of suppressing strong negative image formation can be maintained.

From the above, when an AC voltage is applied to the charging member by the voltage applying means provided in the apparatus main body of the image forming apparatus, the work function W(D) of the developer and the work function W(S) of the sheet member 14 are as follows. It is preferable to satisfy the relational expression (A) of As a result, it is possible to prevent the residual toner from reaching the cleaning blade while being strongly negatively charged. As a result, it is possible to prevent image damage due to poor cleaning.

0≦W(D)−W(S)≦0.23 (A)

Moreover, the present invention is not limited to the configuration of the above embodiment. In the above embodiment, one type of material was used as the collection sheet member 14, but instead of PPS, a two-layer structure in which the base material is formed of a PET sheet and the PPS sheet is laminated thereon is used. may The effects of the present invention can be exhibited if the work function difference between the material of the surface in contact with the photosensitive drum and the toner satisfies the formula (A).

Further, in the above embodiment, the toner A has a styrene-based resin as the binder resin, an ester compound as the releasing agent, and finely dispersed crystalline polyester in the toner. The present invention is not limited to this toner A. Even when other materials are used, the effect of the present invention can be exhibited if the work function difference between the toner and the collection sheet member satisfies the formula (A).

Further, in Example 5, Vpp during non-image formation is changed to a larger value than during image formation. The present invention is not limited to this embodiment, and can clean off toner adhering to the surface of the collection sheet member by increasing Vpp as a non-image forming operation at a desired timing and rotating the photosensitive drum for a desired time. .
INDUSTRIAL APPLICABILITY The present invention can be used for image forming apparatuses such as copiers and printers and process cartridges used therein.

DESCRIPTION OF SYMBOLS 1... Photosensitive drum 2... Charging roller 8... Cleaning member 14... Recovery sheet member B... Cartridge

Claims (12)

a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with a rotatable image carrier that carries a developer image made of developer, and removes the cleaning material from the image carrier. a cleaning member for removing the developer remaining on the image carrier after the developer image is transferred;
a charging member attached to the cleaning frame for charging the image carrier;
A shaft having one end attached to the cleaning frame and the other end contacting the image carrier at a position upstream of the contact position of the cleaning member and the image carrier in the rotational direction of the image carrier . a sheet member;
A cleaning device comprising:
An alternating voltage can be applied to the charging member,
A cleaning device, wherein a work function W(D) of the developer and a work function W(S) of the sheet member satisfy the following formula (A).
0≦W(D)−W(S)≦0.23 (A) The other end of the sheet member is a free end,
δ is the deflection amount of the sheet member, E is Young's modulus, h is the thickness, L is the distance from one end of the sheet member to the contact nip between the sheet member and the image carrier, and Poisson's ratio of the sheet member is 1. The contact pressure P of the sheet member calculated by the following formula (B) is 1.32×10 ⁻⁵ or more and 1.74×10 ⁻² or less, where ν. The cleaning device according to .
P=δEh ³ /{4L ³ (1−ν ² )} (B) The other end of the sheet member is a free end,
2. A direction extending from one end of the sheet member to the other end of the sheet member is the same as the direction of rotation of the image carrier in a region with which the other end of the sheet member abuts. 3. The cleaning device according to 2. 2. A direction extending from one end of said cleaning member to the other end of said cleaning member is opposite to said rotating direction of said image carrier in a region with which said other end of said cleaning member abuts. 4. The cleaning device according to any one of 3. The cleaning device according to any one of claims 1 to 4, wherein the material of the sheet member is polyphenylene sulfide (PPS). The cleaning device according to any one of claims 1 to 4, wherein the material of the sheet member is polytetrafluoroethylene (PTFE). 7. The cleaning device according to claim 1, wherein the sheet member has a thickness of 50 μm or more and 100 μm or less. The sheet member is adhered to the cleaning frame constituting an accommodating portion that accommodates the developer removed by the cleaning member together with the cleaning member, and the developer removed by the cleaning member is discharged from the accommodating portion to the outside. 8. The cleaning device according to any one of claims 2 to 7, which also serves as a sealing member for preventing leakage. The charging member includes
9. The method according to any one of claims 1 to 8, wherein an AC peak-to-peak voltage having a voltage value higher than that of the AC peak-to-peak voltage that can be applied during image formation can be applied during non-image formation. Cleaning device as described. 10. The cleaning device according to claim 1, wherein the developer contains an external additive. an image carrier that carries a developer image made of developer and is rotatable;
a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with the image carrier, and after the developer image is transferred from the image carrier, the cleaning member contacts the image carrier. a cleaning member for removing residual developer;
a charging member attached to the cleaning frame for charging the image carrier;
A shaft having one end attached to the cleaning frame and the other end contacting the image carrier at a position upstream of the contact position of the cleaning member and the image carrier in the rotational direction of the image carrier . a cleaning device having a coating member;
A cartridge that is detachable from the main body of an image forming apparatus,
An alternating voltage can be applied to the charging member,
A cartridge, wherein the work function W(D) of the developer and the work function W(S) of the sheet member satisfy the following formula (A).
0≦W(D)−W(S)≦0.23 (A) an image carrier that carries a developer image made of developer and is rotatable;
a transfer member that transfers the developer image formed on the image carrier carried by the image carrier onto a recording material;
a cleaning frame;
A cleaning member, one end of which is attached to the cleaning frame and the other end of which is a free end, is in contact with the image carrier, and after the developer image is transferred from the image carrier, the cleaning member contacts the image carrier. a cleaning member for removing residual developer;
a charging member attached to the cleaning frame for charging the image carrier;
One end is attached to the cleaning frame, and the other end abuts on the image carrier at a position upstream of the contact position of the cleaning member and the image carrier in the rotational direction of the image carrier.
a cleaning device having a sheet member;
An image forming apparatus for forming an image on the recording material,
An alternating voltage can be applied to the charging member,
An image forming apparatus, wherein a work function W(D) of the developer and a work function W(S) of the sheet member satisfy the following formula (A).
0≦W(D)−W(S)≦0.23 (A)

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