JP2014170122A - Cleaning blade, cleaning device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade that controls a supply amount of lubricant according to a slide state with a cleaning target member.SOLUTION: A cleaning blade contains, in an area including a part in contact at least with a cleaning target member (contact corner part 3A), a thixotropic composition that includes lubricant and satisfies the following formula (A): η(1)/η(100)≥18, in which η(1) represents a viscosity (Pa s) of the thixotropic composition when a shear force 1 sis applied at 30°C; and η(100) represents a viscosity (Pa s) when a shear force 100 sis applied at 30°C.

Description

  The present invention relates to a cleaning blade, a cleaning device, a process cartridge, and an image forming apparatus.

  2. Description of the Related Art Conventionally, in electrophotographic copying machines, printers, facsimiles, and the like, a cleaning blade has been used as a cleaning means for removing residual toner and the like on the surface of an image carrier such as a photoconductor. The cleaning blade is not particularly limited to these, and is used as a means for cleaning the surfaces of various members to be cleaned.

For example, Patent Document 1 discloses that a low-friction film is formed on the surface of a photoreceptor belt by applying a toner made of polymer resin powder, zinc stearate powder, silica powder, or the like, or zinc stearate powder. An image forming apparatus is disclosed in which the low friction film is formed in a predetermined area on the upstream side in the moving direction of the photosensitive belt from the contact position of the cleaning blade.
Patent Document 2 also proposes a method of supplying a thixotropic lubricant onto the photoreceptor.

JP-A-5-119676 JP 2008-70499 A

  An object of the present invention is to provide a cleaning blade in which the amount of lubricant supplied is controlled in accordance with the state of sliding with a member to be cleaned.

In order to achieve the above object, the following invention is provided.
The invention according to claim 1
A cleaning blade containing a thixotropic composition satisfying the following formula (A) and containing a lubricant in a region including at least a portion in contact with a member to be cleaned.
Formula (A): η (1) / η (100) ≧ 18
(In formula (A), η (1) indicates the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C. η (100) indicates a temperature of 30 The viscosity (Pa · s) of the thixotropic composition when a shearing force of 100 s ⁻¹ is applied at ° C. is shown.)

The invention according to claim 2
The cleaning blade according to claim 1, wherein the thixotropic composition satisfies the following formula (B).
Formula (B): 3000 Pa · s ≧ η (1) ≧ 50 Pa · s
(In formula (B), η (1) represents the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C.)

The invention according to claim 3
The cleaning blade according to claim 1, wherein the thixotropic composition contains silica particles obtained by a dry process.

The invention according to claim 4
A cleaning device comprising the cleaning blade according to any one of claims 1 to 3.

The invention according to claim 5
An image carrier,
A charging device for charging the image carrier;
An electrostatic latent image forming apparatus that forms an electrostatic latent image on the surface of the charged image carrier;
A developing device for developing the electrostatic latent image formed on the surface of the image carrier with toner to form a toner image;
A transfer device for transferring a toner image formed on the image carrier onto a recording medium;
The cleaning device according to claim 4, wherein the cleaning blade is brought into contact with the surface of the image carrier after the toner image is transferred by the transfer device, and cleaning is performed.
An image forming apparatus.

The invention according to claim 6
A process cartridge comprising the cleaning device according to claim 4 and detachable from the image forming apparatus.

  According to the first aspect of the present invention, compared with the case where the region including the portion in contact with the member to be cleaned satisfies the formula (A) and does not contain the thixotropic composition including the lubricant, the sliding with the member to be cleaned is performed. A cleaning blade in which the supply amount of the lubricant is controlled according to the state is provided.

  According to the second aspect of the present invention, there is provided a cleaning blade in which the supply amount of the lubricant is controlled according to the sliding state with the member to be cleaned as compared with the case where the thixotropic composition does not satisfy the formula (B). Provided.

  According to the invention of claim 3, compared with the case where the thixotropic composition does not contain silica particles obtained by a dry process and contains other particles, the lubricant is supplied evenly to the contact portion with the member to be cleaned. A cleaning blade is provided.

  According to the inventions according to claims 4, 5 and 6, the cleaning blade containing the thixotropic composition satisfying the formula (A) and containing the lubricant in the region including the portion in contact with the member to be cleaned is not provided. As compared with the case, there are provided a cleaning device, a process cartridge, and an image forming apparatus in which the life is extended and contamination of other members by the lubricant is suppressed.

It is the schematic which shows an example of the cleaning blade in this embodiment. FIG. 3 is a schematic diagram illustrating a state where a cleaning blade in contact with an image carrier that is driven in the embodiment. 1 is a schematic diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic cross section which shows an example of the cleaning apparatus in this embodiment. It is the schematic which shows another example of the cleaning blade in this embodiment. It is the schematic which shows another example of the cleaning blade in this embodiment.

  Hereinafter, embodiments of a cleaning blade, a cleaning device, a process cartridge, and an image forming apparatus of the present invention will be described in detail.

<Cleaning blade>
The cleaning blade according to this embodiment contains a thixotropic composition in a region including at least a portion that comes into contact with the member to be cleaned. The thixotropic composition satisfies the following formula (A) and contains a lubricant.
Formula (A): η (1) / η (100) ≧ 18
(In formula (A), η (1) indicates the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C. η (100) indicates a temperature of 30 The viscosity (Pa · s) of the thixotropic composition when a shearing force of 100 s ⁻¹ is applied at ° C. is shown.)

In this specification, a member constituting an area including a portion of the cleaning blade that comes into contact with the member to be cleaned is referred to as a “contact member”. The cleaning blade according to the present embodiment may be composed of only the contact member, that is, the thixotropic composition may be contained in the entire cleaning blade.
Further, in the cleaning blade, when the contact member and the region other than the contact member are made of different materials, a member constituting the region other than the contact member is referred to as a “non-contact member”. When the cleaning blade has a contact member and a non-contact member, the thixotropic composition is contained in at least the contact member. The non-contact member may be composed of one kind of material or may be composed of two or more kinds of members having different materials.

Further, “thixotropic” in the thixotropic composition means thixotropic properties, and when the shearing force is not applied or the applied shearing force is low, the composition becomes solid or has a high viscosity. On the other hand, when the applied shearing force is increased, the viscosity is lowered. In the formula (A), the viscosity of the thixotropic composition when the shearing force 100s ⁻¹ is applied is reduced to 1/18 or less of the viscosity of the thixotropic composition when the shearing force 1s ⁻¹ is applied. In other words, the thixotropic composition in the present embodiment represents that the viscosity decreases when a high shear force is applied.

Conventionally, with a cleaning blade that contacts the member to be cleaned and cleans the surface, the contact portion slides as the member to be cleaned is driven, and wear may occur at the sliding portion. Was inferior.
On the other hand, a method of supplying a liquid lubricant from the outside to the contact portion between the cleaning blade and the member to be cleaned has been performed from the viewpoint of reducing the frictional force at the contact portion and suppressing the wear of the cleaning blade. However, when liquid lubricant is supplied from the outside, even if a proper amount of lubricant is supplied to the contact portion and the sliding between the member to be cleaned and the cleaning blade is stable, Even when the amount of the lubricant was reduced and the sliding became unstable, it was not efficient because a certain amount of liquid lubricant was supplied from the outside. Furthermore, excessive liquid lubricant may contaminate other members.
Therefore, it has been required to control the supply amount of the lubricant according to the sliding state of the cleaning blade.

On the other hand, in the cleaning blade according to the present embodiment, the supply amount of the lubricant is appropriately controlled according to the sliding state of the cleaning blade and the member to be cleaned by the above configuration.
This reason is considered as the reason shown below.

First, the cleaning blade according to the present embodiment is disposed in contact with the surface of the member to be cleaned 31 as shown in FIG. When the member to be cleaned 31 is driven, as shown in FIG. 2, the contact portion between the cleaning blade 342 and the member to be cleaned 31 slides to form the nip portion T, and the surface of the member to be cleaned 31 is cleaned.
When the thixotropic composition is contained in at least the contact member of the cleaning blade 342 disposed in this state, the frictional force between the member to be cleaned 31 and the cleaning blade 342 is small and the posture of the cleaning blade 342 is stable. Is in a state where it is difficult to apply a shearing force to the thixotropic composition contained in the contact member of the cleaning blade 342. In a state where it is difficult to apply a shearing force, the thixotropic composition is considered to have a high viscosity due to its thixotropic property. Therefore, the thixotropic composition contained in the contact member does not flow out to the surface of the cleaning blade 342, and the amount of the thixotropic composition supplied to the contact portion (nip portion T) between the cleaning blade 342 and the member to be cleaned 31 is also increased. It is thought to be reduced.

  On the other hand, when the frictional force between the member to be cleaned 31 and the cleaning blade 342 becomes large and the posture of the cleaning blade 342 becomes unstable, a high shearing force is applied to the thixotropic composition contained in the contact member. . When a high shearing force is applied, the viscosity of the thixotropic composition decreases due to its thixotropy, flows out to the surface of the cleaning blade 342, and a contact portion (nip portion T) between the cleaning blade 342 and the member to be cleaned 31. It is believed that the amount of thixotropic composition supplied to the will increase. That is, the lubricant contained in the thixotropic composition is supplied to the nip portion T. Then, due to the lubricating function of the lubricant, the force applied to the nip portion T is reduced, and the posture of the cleaning blade 342 is stabilized. For this reason, it is considered that slipping of foreign matters to be cleaned existing on the surface of the member to be cleaned 31 is suppressed.

  When the thixotropic composition satisfies the formula (A) and has a low shearing force, the thixotropic composition maintains a high viscosity and remains on the contact member of the cleaning blade 342. Thus, when the supply of the lubricant to the nip portion T is suppressed, and the posture of the cleaning blade 342 becomes unstable and a high shearing force is applied, the viscosity of the thixotropic composition is rapidly reduced and the cleaning blade It is considered that the cleaning blade 342 flows out of the nozzle 342 and is easily supplied to the nip portion T, and the cleaning blade 342 is stabilized in posture.

  From the above, in the cleaning blade according to the present embodiment, it is considered that the supply amount of the lubricant is appropriately controlled according to the sliding state with the member to be cleaned, and defective cleaning is suppressed. Moreover, since supply of excess lubricant to the nip portion T is reduced, it is considered that contamination of other members by the lubricant is also reduced.

  In addition, in the cleaning blade according to the present embodiment, since the posture of the cleaning blade is stabilized due to the lubricating function of the lubricant contained in the thixotropic composition, an excessive mechanical load is applied to the cleaning blade and the member to be cleaned. It is thought that it is suppressed that it is applied. As a result, it is considered that the life of the cleaning blade is easily realized.

  Next, the configuration of the cleaning blade according to the present embodiment will be described in detail.

First, each part of the cleaning blade will be described with reference to the drawings. In the following, as shown in FIG. 1, the cleaning blade comes into contact with the driven image carrier (photoreceptor drum) 31 to clean the surface of the image carrier 31 and a contact angle 3A. 3A constitutes one side and the front end surface 3B faces the upstream side in the driving direction (arrow A direction), and the contact corner 3A constitutes one side and the driving direction (arrow A direction). 3C facing the downstream side, and a back surface 3D that shares one side with the tip surface 3B and faces the abdominal surface 3C.
Further, the direction parallel to the contact corner 3A is the depth direction, the direction from the contact corner 3A where the tip surface 3B is formed is the thickness direction, and the side where the abdominal surface 3C is formed from the contact corner 3A. The direction is referred to as the width direction.
For the sake of convenience, FIG. 1 depicts the direction in which the image carrier (photosensitive drum) 31 is driven as an arrow A, but FIG. 1 shows a state in which the image carrier 31 is stopped.

  FIG. 1 is a schematic diagram illustrating a cleaning blade according to the first embodiment, and is a diagram illustrating a state in which the cleaning blade is in contact with the surface of the photosensitive drum. FIG. 5 is a diagram showing a state in which the cleaning blade according to the second embodiment is in contact with the surface of the photosensitive drum, and FIG. 6 is a diagram in which the cleaning blade according to the third embodiment is in contact with the surface of the photosensitive drum.

  The cleaning blade 342A according to the first embodiment shown in FIG. 1 is composed of a single material as a whole, including a portion (contact angle portion) 3A that contacts the photosensitive drum 31, that is, only the contact member. It is the aspect which consists of.

  The cleaning blade according to this embodiment includes a portion (contact angle portion) 3A that contacts the photosensitive drum 31 and is formed over the entire surface of the abdominal surface 3C, as in the second embodiment shown in FIG. The two-layer configuration includes a first layer 3421B made of a contact member and a second layer 3422B as a back layer formed on the back surface 3D side of the first layer and made of a material different from that of the contact member. May be.

Furthermore, the cleaning blade according to the present embodiment includes a portion that contacts the photosensitive drum 31, that is, a contact angle portion 3A as in the third embodiment shown in FIG. A contact member (edge member) 3421C made of a contact member, and a front end surface in the width direction of the contact member 3421C and the front end surface in the width direction. The back surface 3422C made of a material different from the contact member, which covers the side opposite to 3A, that is, forms a part other than the contact member 3421C, may be provided.
In addition, although the example of the member which has the shape of the cylinder cut into 1/4 as a contact member was shown in FIG. 6, it is not limited to this. The contact member may be, for example, a shape in which an elliptical cylinder is cut into ¼, a square quadrangular prism, a rectangular quadrangular prism, or the like.

(Contact member)
The contact member in the cleaning blade according to the present embodiment contains at least a thixotropic composition.

-Thixotropic composition-
The thixotropic composition contains a lubricant and satisfies the following formula (A) (preferably the following formula (A1), more preferably the following formula (A2)).
Formula (A): η (1) / η (100) ≧ 18
Formula (A1): 79 ≧ η (1) / η (100) ≧ 34.8
Formula (A2): 78 ≧ η (1) / η (100) ≧ 52

In formula (A), formula (A1), and formula (A2), η (1) indicates the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C. η (100) indicates the viscosity (Pa · s) of the thixotropic composition when a shearing force of 100 s ⁻¹ is applied at a temperature of 30 ° C.

  In Formula (A), when “η (1) / η (100)” is less than 18, the posture of the cleaning blade 342 becomes unstable, and a high shear force is applied to the thixotropic composition in the contact member. In some cases, the viscosity does not decrease and the thixotropic composition (lubricant contained therein) is difficult to be supplied to the nip T of the cleaning blade 342, resulting in poor cleaning.

The value of η (1) in the thixotropic composition is more preferably a lower limit of 0.1 Pa · s or more, more preferably 1 Pa · s or more, further preferably 10 Pa · s or more, and further preferably 50 Pa · s or more. .
The upper limit of the value of η (1) is preferably 3000 Pa · s or less, more preferably 1000 Pa · s or less, further preferably 750 Pa · s or less, and further preferably 500 Pa · s or less.

The thixotropic composition preferably satisfies the following formula (B).
Formula (B): 3000 Pa · s ≧ η (1) ≧ 50 Pa · s
(In the formula (B), η (1) represents the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C.)

By setting “η (1)” to 0.1 Pa · s or higher, the posture of the cleaning blade 342 is stable, and the viscosity is high when the shearing force applied to the thixotropic composition in the contact member is low. And the supply of the thixotropic composition (the lubricant contained therein) to the nip T of the cleaning blade 342 is effectively suppressed.
On the other hand, by setting “η (1)” to 3000 Pa · s or less, compatibility with a resin such as urethane rubber can be obtained, dispersibility is improved, and the thixo composition is spread over the entire cleaning blade. is there.

Here, “thixotropy” means thixotropic property, and when no shear force is applied or when the applied shear force is low, it is applied while being in a solid state or in a high viscosity state. When the shearing force increases, the viscosity becomes low.
“Η (1)” and “η (100)” are “RS-CPS cone plate type R / S made by Brookfield” with respect to the sample obtained by separating the thixotropic composition from the contact member of the cleaning blade. It is a value measured at a temperature of 30 degrees using a rheometer (spindle “RC3-25-1” is applied).

  The thixotropic composition is separated from the contact member by collecting the thixotropic composition deposited on the contact member of the cleaning blade.

  From the viewpoint of handling, the thixotropic composition preferably has a property of having a shape retention force when no shear force is applied.

  The thixotropic composition includes, for example, a configuration including a lubricant (a lubricant having no thixotropy alone) and a granular material. By including the granular material, it is easy to achieve thixotropy.

Lubricants (lubricants that do not have thixotropy alone) include metal octylate soap, metal naphthenate soap, dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, cyclic methyl silicone oil, liquid paraffin, fluorine Oil, higher alcohol oil, higher fatty acid oil and the like can be mentioned.
Among these, dimethyl silicone oil is preferable as the lubricant from the viewpoint of extending the life of the cleaning blade.

Examples of the granular material include inorganic particles and organic particles.
Examples of inorganic particles include silica, titanium oxide, pennite, montmorillonite, bentonite, calcium carbonate, and the like.
Examples of the organic particles include hydrogenated castor oil, fatty acid amide, polyolefin, calcium soap, sodium soap, aluminum soap, lithium soap, PTFE, and the like.

Among these, as a granular material, the silica particle (dry silica) obtained by the dry manufacturing method is good, for example, fumed silica is mentioned.
Of these, silica particles whose surface is hydrophilized are preferred. Silica particles whose surface has been hydrophilized have good compatibility with a resin described later constituting the contact member, and particularly excellent compatibility with a urethane resin suitably used for the contact member. Therefore, the dispersibility of the thixotropic composition in the contact member is improved, and the lubricant is supplied to the nip portion T without unevenness.

  Examples of the hydrophilic treatment for hydrophilizing the surface of the silica particles include an anionic treatment agent such as an aminosilazane, a cationic coupling carboxylic acid group having a quaternary ammonium salt, and an inorganic material such as water. Examples thereof include aluminum oxide, sodium metaphosphate, zirconia, alumina mixed with stearic acid, and metal oxides such as titanium dioxide, zinc oxide and magnesium oxide.

The volume average particle diameter of the inorganic particles is preferably 5 nm or more and 30 nm or less, and preferably 8 nm or more and 20 nm or less, from the viewpoint of imparting thixotropy, improving the external additive capturing function, and extending the life of the cleaning blade. .
The volume average particle size of the inorganic particles is determined by observing 100 primary particles of inorganic particles in a state mixed with the thixotropic composition using a scanning electron microscope (SEM) apparatus, and analyzing the primary particles for each particle by image analysis of the primary particles. The long diameter and the shortest diameter are measured, and the equivalent sphere diameter is measured from the intermediate value. The 50% diameter (D50v) in the cumulative frequency of the obtained equivalent sphere diameter is defined as the average particle diameter (that is, volume average particle diameter) of the inorganic particles.

  From the viewpoint of imparting thixotropy and extending the life of the cleaning blade, the content of the particulate matter is preferably 10% by mass or more and 80% by mass or less, and preferably 15% by mass or more and 50% by mass with respect to the lubricant. It is below mass%.

  In the thixotropic composition, the thixotropy satisfying the formula (A) and the above formula (B) is controlled by, for example, the type of lubricant, the type of granular material, the particle size, the content, and the like.

-Resin-
The contact member in the cleaning blade according to the present embodiment is not particularly limited, but preferably contains a resin. Examples of the resin include polyurethane rubber, silicon rubber, fluorine rubber, propylene rubber, and butadiene rubber. In particular, polyurethane rubber is desirable, and highly crystallized polyurethane rubber is more desirable.

Polyurethane rubber is usually synthesized by polymerizing polyisocyanate and polyol. Moreover, you may use resin which has a functional group which can react with an isocyanate group other than a polyol. The polyurethane rubber preferably has a hard segment and a soft segment.
Here, the “hard segment” and the “soft segment” are the materials constituting the former in the polyurethane rubber material, the material constituting the former being relatively harder than the material constituting the latter. Means a segment made of a material relatively softer than the material constituting the former.

  The combination of the material constituting the hard segment (hard segment material) and the material constituting the soft segment (soft segment material) is not particularly limited. One is relatively hard with respect to the other and the other is against the other. However, in the present embodiment, the following combinations are suitable.

-Soft segment material First, as the soft segment material, as the polyol, polyester polyol obtained by dehydration condensation of diol and dibasic acid, polycarbonate polyol obtained by reaction of diol and alkyl carbonate, polycaprolactone polyol, polyether polyol, etc. Is mentioned. In addition, as a commercial item of the said polyol used as a soft segment material, the Daicel Chemical Co., Ltd. Plaxel 205, Plaxel 240, etc. are mentioned, for example.

Hard segment material As the hard segment material, it is desirable to use a resin having a functional group capable of reacting with an isocyanate group. In addition, a flexible resin is desirable, and an aliphatic resin having a linear structure is more desirable from the viewpoint of flexibility. As a specific example, it is desirable to use an acrylic resin containing two or more hydroxyl groups, a polybutadiene resin containing two or more hydroxyl groups, an epoxy resin having two or more epoxy groups, and the like.

As a commercial item of the acrylic resin containing two or more hydroxyl groups, for example, Acto Flow (grade: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) manufactured by Soken Chemical Co., Ltd. may be mentioned.
As a commercial item of the polybutadiene resin containing two or more hydroxyl groups, Idemitsu Kosan Co., Ltd. make, R-45HT etc. are mentioned, for example.

The epoxy resin having two or more epoxy groups does not have a hard and brittle property like a conventional general epoxy resin, and preferably has a softer toughness than a conventional epoxy resin. As the epoxy resin, for example, in terms of molecular structure, those having a structure (flexible skeleton) that can increase the mobility of the main chain in the main chain structure are suitable. Examples include an alkylene skeleton, a cycloalkane skeleton, a polyoxyalkylene skeleton, and the like, and a polyoxyalkylene skeleton is particularly preferable.
In terms of physical properties, an epoxy resin having a lower viscosity than the molecular weight of the conventional epoxy resin is preferable. Specifically, the weight average molecular weight is preferably in the range of 900 ± 100, the viscosity at 25 ° C. is preferably in the range of 15000 ± 5000 mPa · s, and more preferably in the range of 15000 ± 3000 mPa · s. desirable. As a commercial item of the epoxy resin which has this characteristic, the product made from DIC, EPLICON EXA-4850-150, etc. are mentioned, for example.

When a hard segment material and a soft segment material are used, the mass ratio of the material constituting the hard segment to the total amount of the hard segment material and the soft segment material (hereinafter referred to as “hard segment material ratio”) is 10% by mass or more and 30% by mass or less. It is desirable to be within the range of 13 mass% to 23 mass%, and it is even more desirable to be within the range of 15 mass% to 20 mass%.
When the hard segment material ratio is 10% by mass or more, wear resistance is obtained, and good cleaning properties are maintained over a long period of time. On the other hand, when the hard segment material ratio is 30% by mass or less, it does not become too hard, and flexibility and extensibility are obtained, chipping is suppressed, and good cleaning properties are maintained over a long period of time. Is done.

-Polyisocyanate Examples of the polyisocyanate used for the synthesis of the polyurethane rubber include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1, Examples include 5-naphthalene diisocyanate (NDI) and 3,3-dimethylphenyl-4,4-diisocyanate (TODI).
In addition, from the viewpoint of easy formation of a hard segment aggregate having a required size (particle diameter), as the polyisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), More preferred is hexamethylene diisocyanate (HDI).

The blending amount with respect to 100 parts by mass of the resin having a functional group capable of reacting with the isocyanate group of the polyisocyanate is preferably 20 parts by mass or more and 40 parts by mass or less, more preferably 20 parts by mass or more and 35 parts by mass or less, More preferably, it is more than 30 parts by mass.
When the amount is 20 parts by mass or more, a large amount of urethane bond is ensured, hard segment growth occurs, and the required hardness is obtained. On the other hand, when the amount is 40 parts by mass or less, the hard segment does not become too large, the extensibility is obtained, and the occurrence of chipping of the cleaning blade is suppressed.

-Crosslinking agent As a crosslinking agent, diol (bifunctional), triol (trifunctional), tetraol (tetrafunctional), etc. are mentioned, You may use these together. An amine compound may be used as a crosslinking agent. In addition, it is desirable that it is crosslinked using a trifunctional or higher functional crosslinking agent. Examples of the trifunctional crosslinking agent include trimethylolpropane, glycerin, triisopropanolamine and the like.

  As for the compounding quantity with respect to 100 mass parts of resin which has a functional group which can react with respect to the isocyanate group of a crosslinking agent, 2 mass parts or less are desirable. By being 2 parts by mass or less, molecular motion is not restricted by chemical crosslinking, and a hard segment derived from a urethane bond by aging grows greatly, and the required hardness is easily obtained.

-Molding method of a contact member The polyurethane rubber which comprises the said contact member in this embodiment manufactures the general manufacturing method of polyurethane, such as the prepolymer method and the one-shot method. The prepolymer method is suitable for this embodiment because a polyurethane having excellent strength and abrasion resistance is obtained, but is not limited by the production method.

  Such polyurethane rubber is molded by blending the above-described polyol with an isocyanate compound and a crosslinking agent, and further mixing the above-mentioned thixotropic composition. The cleaning blade contact member is formed by forming the cleaning blade-forming composition prepared by the above method into a sheet shape using, for example, centrifugal molding or extrusion molding, and performing cutting processing or the like. It is produced by this.

  Here, an example is given and the detail of the manufacturing method of a contact member is demonstrated.

First, a soft segment material (for example, polycaprolactone polyol) and a hard segment material (for example, an acrylic resin containing two or more hydroxyl groups) are mixed (for example, a mass ratio of 8: 2).
Next, an isocyanate compound (for example, 4,4′-diphenylmethane diisocyanate) is added to the mixture of the soft segment material and the hard segment material, and the reaction is performed in, for example, a nitrogen atmosphere. The temperature at this time is preferably 60 ° C. or higher and 150 ° C. or lower, and more preferably 80 ° C. or higher and 130 ° C. or lower. The reaction time is preferably 0.1 hour or more and 3 hours or less, more preferably 1 hour or more and 2 hours or less.

Subsequently, an isocyanate compound is further added and reacted in, for example, a nitrogen atmosphere to obtain a prepolymer. The temperature at this time is preferably 40 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 90 ° C. or lower. The reaction time is preferably 30 minutes or more and 6 hours or less, and more preferably 1 hour or more and 4 hours or less.
Next, the prepolymer is heated and degassed under reduced pressure. The temperature at this time is preferably 60 ° C. or higher and 120 ° C. or lower, and more preferably 80 ° C. or higher and 100 ° C. or lower. The reaction time is preferably 10 minutes or more and 2 hours or less, more preferably 30 minutes or more and 1 hour or less.
Thereafter, a crosslinking agent (for example, 1,4-butanediol or trimethylolpropane) is added to the prepolymer, and a thixotropic composition is further mixed to prepare a composition for forming a cleaning blade.

Subsequently, the composition for forming the cleaning blade is poured into a mold of a centrifugal molding machine to cause a curing reaction. In this case, the mold temperature is preferably 80 ° C. or higher and 160 ° C. or lower, and more preferably 100 ° C. or higher and 140 ° C. or lower. The reaction time is preferably 20 minutes or more and 3 hours or less, more preferably 30 minutes or more and 2 hours or less.
Further, a cross-linking reaction is performed, and after cooling, cutting is performed to form a cleaning blade. The temperature of aging heating during the crosslinking reaction is preferably 70 ° C. or higher and 130 ° C. or lower, more preferably 80 ° C. or higher and 130 ° C. or lower, and further preferably 100 ° C. or higher and 120 ° C. or lower. The reaction time is preferably 1 hour or more and 48 hours or less, and more preferably 10 hours or more and 24 hours or less.

Physical Properties In the cleaning blade in this embodiment, the endothermic peak top temperature (melting temperature) by differential scanning calorimetry (DSC) is preferably 180 ° C. or higher, more preferably 185 ° C. or higher, and 190 ° C. More preferably, the above is true. The upper limit is preferably 220 ° C. or lower, more preferably 215 ° C. or lower, and further preferably 210 ° C. or lower.

  The endothermic peak top temperature (melting temperature) is determined according to ASTM D3418-99 by differential scanning calorimetry (DSC). For the measurement, a Diamond-DSC manufactured by PerkinElmer is used, the temperature detection of the device detection unit is performed using the melting temperature of indium and zinc, and the heat amount is corrected using the heat of fusion of indium. An aluminum pan is used as a measurement sample, and an empty pan is set as a control for measurement.

Examples of means for controlling the endothermic peak top temperature within the above range include a molding method under molding conditions that can suppress unevenness of molecular arrangement. Specifically, when preparing the polyurethane composition, the temperature of the polyol or prepolymer is lowered, or the temperature of curing / molding is lowered, so that the progress of the crosslinking is slowed. By setting these temperatures low (polyol and prepolymer temperature, curing / molding temperature) to lower the reactivity, the urethane bond agglomerates and hard segment crystals are obtained. The temperature is adjusted so that the particle diameter of the crystal becomes the required crystal diameter.
Thereby, the molecules contained in the polyurethane composition are arranged side by side, and when the DSC is measured, a polyurethane rubber containing a crystal having an endothermic peak top temperature of crystal melting energy in the above range is molded.
The amounts of polyol, polyisocyanate, and crosslinking agent, the ratio of crosslinking agent, and the like are adjusted to the required ranges.

Moreover, in this embodiment, it is desirable that the polyurethane rubber has a hard segment and a soft segment, and the average particle diameter of the hard segment aggregate is 5 μm or more and 20 μm or less.
When the average particle size of the hard segment aggregates is 5 μm or more, the crystal area on the blade surface is increased, and there is an advantage in improving the slidability. On the other hand, by being 20 μm or less, there is an advantage that toughness (chip resistance) is not lost while maintaining low friction.
The average particle diameter is more preferably 5 μm or more and 15 μm or less, and further preferably 5 μm or more and 10 μm or less.

The particle size distribution (standard deviation σ) of the hard segment aggregates is preferably 2 μm or more.
The particle size distribution (standard deviation σ) of the hard segment aggregates is 2 μm or more, which means that particles of various particle sizes are mixed, and the contact area with the soft segment increases due to the small aggregates. As a result, the effect of increasing the hardness can be obtained. On the other hand, the effect of improving the slidability can be obtained by the large aggregate.
The particle size distribution is more desirably 2 μm or more and 5 μm or less, and further desirably 2 μm or more and 3 μm or less.

In addition, the average particle diameter and particle size distribution of a hard segment aggregate are measured with the following method. Using a polarizing microscope (Olympus BX51-P), an image was taken at a magnification of × 20, image processing was performed to binarize the image, and 5 points per cleaning blade (5 aggregates per point) Measurement), the particle diameter is measured for 20 cleaning blades, and the average particle diameter is calculated from a total of 500 cleaning blades.
Note that image binarization uses image processing software OLYMPUS Stream essentials (manufactured by Olympus), and adjusts the threshold of hue / saturation / luminance so that the crystal part is black and the amorphous part is white.

Further, the particle size distribution (standard deviation σ) is calculated from the measured 500 particle diameters by the following formula.
Standard deviation σ (μm) = √ {(X1-M) ² + (X2-M) ² +...
... + (X500-M) ² } / 500
Xn: measured particle diameter n (n = 1 to 500)
M: Average value of measured particle diameter

  Means for controlling the particle size and particle size distribution of the hard segment aggregates to the above ranges are not particularly limited, but for example, reaction control by a catalyst, three-dimensional network control by a crosslinking agent, crystal growth control by aging conditions And the like.

In the contact member, the ratio of physical crosslinking (crosslinking by hydrogen bonding between hard segments) to chemical crosslinking (crosslinking by a crosslinking agent) “1” in polyurethane rubber is 1: 0.8 to 1: 2.0. It is desirable that the ratio is 1: 1 to 1: 1.8.
When the ratio of physical crosslinking to chemical crosslinking is not less than the above lower limit value, the hard segment aggregate is further grown and the effect of low friction derived from crystals is obtained. On the other hand, the effect of toughness maintenance is acquired by being below the said upper limit.

In addition, the ratio of the said chemical bridge | crosslinking and a physical bridge | crosslinking is computed using the following Moobee-Riviliin formula.
Z = 2C ₁ (λ−1 / λ ² ) + 2C ₂ (1-1 / λ ³ )
Z: Stress, λ: Strain, C ₁ : Chemical crosslink density, C ₂ : Physical crosslink Note that σ and λ at 10% elongation are used from the stress-strain curve by the tensile test.

In the contact member, the ratio of the hard segment to the soft segment “1” in the polyurethane rubber is preferably 1: 0.15 to 1: 0.3, and more preferably 1: 0.2 to 1: 0. .25 is desirable.
When the ratio of the hard segment to the soft segment is equal to or more than the above lower limit value, the amount of hard segment aggregates is increased, so that an effect of low friction is obtained. On the other hand, the effect of toughness maintenance is acquired by being below the said upper limit.

The ratio between the soft segment and hard segment, using ^{1 H-NMR,} calculated isocyanate, chain extender, the composition ratio from the spectrum area of polyol as a soft segment component as a hard segment component.

  The weight average molecular weight of the polyurethane rubber in this embodiment is preferably in the range of 1000 to 4000, and more preferably in the range of 1500 to 3500.

  Next, the cleaning blade of this embodiment is made of a material in which the contact member and the region other than the contact member (non-contact member) are different from each other as in the second embodiment shown in FIG. 5 or the third embodiment shown in FIG. The composition of the non-contact member will be described.

(Non-contact member)
The non-contact member in the cleaning blade according to the present embodiment is not particularly limited, and any known material can be used.
-Rebound resilience It is desirable that the non-contact member is made of a material having a rebound resilience at 50 ° C of 70% or less. Furthermore, it is more desirably 60% or less, and further desirably 50% or less. Further, the lower limit is preferably 30% or more, and more preferably 40% or more.

  The rebound resilience (%) at 50 ° C. is measured in a 50 ° C. environment according to JIS K6255 (1996). When the non-contact member of the cleaning blade has a size larger than the size of the test piece defined in JIS K6255, the above measurement is performed by cutting out the test piece having the size of the test piece. On the other hand, when the non-contact member is smaller than the size of the test piece, the test piece is formed of the same material as the member, and the above measurement is performed on the test piece.

  The method for controlling the 50 ° C. rebound resilience of the non-contact member is not particularly limited. For example, if the non-contact member is polyurethane, the glass transition temperature (Tg) can be reduced by reducing the molecular weight of the polyol or making it hydrophobic. ) Tends to increase.

-Permanent elongation Further, the non-contact member in the cleaning blade according to this embodiment is preferably composed of a material having a 100% permanent elongation of 1.0% or less, and more preferably 0.5% or less. More preferably, it is 0.4% or less. Further, the lower limit is preferably 0.1% or more, and more preferably 0.2% or more.

Here, a method for measuring the 100% permanent elongation (%) will be described.
In accordance with JIS K6262 (1997), a strip-shaped test piece is used, a 100% tensile strain is applied and left for 24 hours.
Ts = (L2-L0) / (L1-L0) × 100
Ts: Permanent elongation
L0: Distance between marked lines before pulling
L1: Distance between marked lines when pulling
L2: Distance between marked lines after pulling When the non-contact member of the cleaning blade is larger than the size of the strip-shaped specimen specified in JIS K6262, the dimension of the strip-shaped specimen from the member The above measurement is carried out by cutting out. On the other hand, when the non-contact member is smaller than the size of the strip-shaped test piece, the strip-shaped test piece is formed of the same material as the member, and the above measurement is performed on the strip-shaped test piece.

  The method for controlling 100% permanent elongation in the non-contact member is not particularly limited. For example, when the non-contact member is polyurethane, the control method varies by adjusting the molecular weight of the polyol. There is a tendency.

  Examples of the material used for the non-contact member include polyurethane rubber, silicon rubber, fluorine rubber, propylene rubber, and butadiene rubber. Of these, polyurethane rubber is preferable. Examples of the polyurethane rubber include ester polyurethane and ether polyurethane, and ester polyurethane is particularly desirable.

There is a method of using a polyol and a polyisocyanate when producing a polyurethane rubber.
Examples of the polyol include polytetramethyl ether glycol, polyethylene adipate, and polycaprolactone.
As polyisocyanates, 2,6-toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), 3,3-dimethyldiphenyl- Examples include 4,4′-diisocyanate (TODI). Of these, MDI is preferable.
Further, examples of the curing agent for curing the polyurethane include curing agents such as 1,4-butanediol, trimethylolpropane, ethylene glycol, and mixtures thereof.

  A specific example will be described as an example. For example, 1,4-butadiol and trimethylolpropane are added as curing agents to a prepolymer produced by mixing and reacting diphenylmethane-4,4-diisocyanate with dehydrated polytetramethyl ether glycol. It is desirable to use a combination. In addition, you may add additives, such as a reaction regulator.

  As a method for producing the non-contact member, a conventionally known method is used depending on the raw material used for production. For example, the non-contact member is formed using centrifugal molding or extrusion molding, and is cut into a predetermined shape. Produced.

(Manufacture of cleaning blades)
In the case of the cleaning blade including only the contact member shown in FIG. 1, the cleaning blade is manufactured by the above-described contact member forming method.

  In the case of a cleaning blade having a multi-layer structure such as the two-layer structure shown in FIG. 5, a first layer as a contact member and a second layer as a non-contact member (in the case of a three-layer structure or more) A cleaning blade is produced by bonding a plurality of layers to each other. As the bonding method, a double-sided tape, various adhesives and the like are preferably used. Alternatively, a plurality of layers may be bonded by pouring the material of each layer into a mold at a time difference during molding and bonding the materials without providing an adhesive layer.

  Further, in the case of the configuration having the contact member (edge member) and the non-contact member (back member) shown in FIG. 6, two contact members 3421C shown in FIG. This corresponds to a shape in which a first mold having a cavity (a region into which a composition for forming a contact member is poured), two contact members 3421C and non-contact members 3422C, and the abdominal surface 3C side are overlapped with each other. A second mold having a cavity is prepared. A composition for forming a contact member is poured into the cavity of the first mold and cured to form a first molded product having a shape in which two contact members 3421C are overlapped. Next, after removing the first mold, the second mold is installed so that the first molded product is further disposed inside the cavity of the second mold. Thereafter, a composition for forming a non-contact member is poured into the cavity of the second mold so as to cover the first molded product and cured, and the two contact members 3421C and the non-contact member 3422C overlap each other on the side of the stomach surface 3C. A second molded product having a different shape is formed. Next, the formed second molded product is cut in the middle, that is, the portion to be the abdominal surface 3C, and the semi-cylindrical contact member is cut in the middle and cut into a quarter-cut cylinder shape, Furthermore, the cleaning blade shown in FIG. 6 is obtained by cutting into a predetermined dimension.

-Application When the member to be cleaned is cleaned using the cleaning blade of the present embodiment, the member to be cleaned to be cleaned is not particularly limited as long as it is a member that requires surface cleaning. For example, when used in an image forming apparatus, toner is further removed from an intermediate transfer body, a charging roll, a transfer roll, a transfer material transport belt, a paper transport roll, and a cleaning brush that removes toner from the image carrier. Examples include detoning rolls. In the present embodiment, an image carrier is particularly desirable.

(Cleaning device, process cartridge and image forming device)
Next, a cleaning device, a process cartridge, and an image forming apparatus using the cleaning blade of this embodiment will be described.
The cleaning device of the present embodiment is not particularly limited as long as the cleaning blade that contacts the surface of the member to be cleaned and cleans the surface of the member to be cleaned is provided with the cleaning blade of the present embodiment. For example, as a configuration example of the cleaning device, a cleaning blade is fixed in a cleaning case having an opening on the cleaning member side so that the edge tip is on the opening side, and is recovered from the surface of the member to be cleaned by the cleaning blade. For example, a configuration including a conveying member that guides foreign matter such as waste toner to a foreign matter collection container can be used. Further, two or more cleaning blades of this embodiment may be used in the cleaning device of this embodiment.

When the cleaning blade of the present embodiment is used for cleaning the image carrier, the force NF (Normal Force) against which the cleaning blade is pressed against the image carrier is 1 in order to suppress image flow during image formation. Desirably, the range is from 3 gf / mm to 2.3 gf / mm, and more desirably from 1.6 gf / mm to 2.0 gf / mm.
Further, the length of the cleaning blade tip portion biting into the image holding member is preferably in the range of 0.8 mm to 1.2 mm, and more preferably in the range of 0.9 mm to 1.1 mm.
The angle W / A (Working Angle) at the contact portion between the cleaning blade and the image carrier is preferably in the range of 8 ° to 14 °, and more preferably in the range of 10 ° to 12 °.

  On the other hand, the process cartridge of this embodiment includes the cleaning device of this embodiment as a cleaning device that contacts the surface of one or more members to be cleaned such as an image carrier or an intermediate transfer member and cleans the surface of the member to be cleaned. The image carrier is not particularly limited, and includes, for example, an aspect that includes an image carrier and the cleaning device of this embodiment that cleans the surface of the image carrier, and is detachable from the image forming device. For example, in the case of a so-called tandem machine having an image carrier corresponding to each color toner, the cleaning device of this embodiment may be provided for each image carrier. In addition, a cleaning brush or the like may be used in addition to the cleaning device of the present embodiment.

-Specific examples of cleaning blades, image forming devices, and cleaning devices-
Next, specific examples of the cleaning blade of the present embodiment, and an image forming apparatus and a cleaning apparatus using the cleaning blade will be described in more detail with reference to the drawings.
FIG. 3 is a schematic diagram illustrating an example of the image forming apparatus according to the present embodiment, and illustrates a so-called tandem type image forming apparatus.
In FIG. 3, 21 is a main body housing, 22 and 22a to 22d are image forming units, 23 is a belt module, 24 is a recording medium supply cassette, 25 is a recording medium conveyance path, 30 is each photosensitive unit, and 31 is a photosensitive drum. , 33 are each developing unit, 34 is a cleaning device, 35, 35a to 35d are toner cartridges, 40 is an exposure unit, 41 is a unit case, 42 is a polygon mirror, 51 is a primary transfer device, 52 is a secondary transfer device, 53 Is a belt cleaning device, 61 is a delivery roll, 62 is a transport roll, 63 is an alignment roll, 66 is a fixing device, 67 is a discharge roll, 68 is a paper discharge unit, 71 is a manual feed device, 72 is a feed roll, 73 is a duplex recording unit, 74 is a guide roll, 76 is a conveyance path, 77 is a conveyance roll, 230 is an intermediate transfer belt, 23 , 232 support roll, 521 secondary transfer roll, 531 denotes a cleaning blade.

  The tandem type image forming apparatus shown in FIG. 3 has image forming units 22 (specifically 22a to 22d) of four colors (in this embodiment, yellow, magenta, cyan, and black) arranged in a main body housing 21. A belt module 23 including an intermediate transfer belt 230 that is circulated and conveyed along the arrangement direction of the image forming units 22 is disposed above the belt module 23, and a recording medium such as paper (see FIG. (Not shown) is provided, and a recording medium transport path 25 serving as a transport path for the recording medium from the recording medium supply cassette 24 is disposed in the vertical direction.

In the present embodiment, the image forming units 22 (22a to 22d) are, for example, for yellow, magenta, cyan, and black (in the order of arrangement in this order) from the upstream side in the circulation direction of the intermediate transfer belt 230. (Not limited) toner image, each photosensitive unit 30, each developing unit 33, and one common exposure unit 40.
Here, the photosensitive unit 30 includes, for example, a photosensitive drum 31, a charging device (charging roll) 32 that charges the photosensitive drum 31 in advance, and a cleaning device 34 that removes residual toner on the photosensitive drum 31. It is an integrated sub-cartridge.

The developing unit 33 develops the electrostatic latent image exposed and formed by the exposure unit 40 on the charged photosensitive drum 31 with a corresponding color toner (for example, negative polarity in the present embodiment). For example, a process cartridge (so-called Customer Replaceable Unit) is configured by being integrated with a sub-cartridge including the photosensitive unit 30.
Of course, the photosensitive unit 30 may be separated from the developing unit 33 to form a single process cartridge. In FIG. 3, reference numeral 35 (35a to 35d) denotes a toner cartridge for supplying each color component toner to each developing unit 33 (the toner supply path is not shown).

  On the other hand, the exposure unit 40 includes, for example, four semiconductor lasers (not shown), one polygon mirror 42, an imaging lens (not shown), and mirrors (see FIG. (Not shown), the light from the semiconductor laser for each color component is deflected and scanned by the polygon mirror 42, and the light image is guided to the exposure point on the corresponding photosensitive drum 31 through the imaging lens and mirror. It is a thing.

  Further, in the present embodiment, the belt module 23 is, for example, a belt in which the intermediate transfer belt 230 is stretched between a pair of support rolls (one is a drive roll) 231 and 232, and the photoreceptor drum of each photoreceptor unit 30. A primary transfer device (primary transfer roll 51 in this example) 51 is disposed on the back surface of the intermediate transfer belt 230 corresponding to 31, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 51, The toner image on the photosensitive drum 31 is electrostatically transferred to the intermediate transfer belt 230 side. Further, a secondary transfer device 52 is disposed at a portion corresponding to the support roll 232 on the downstream side of the most downstream image forming unit 22d of the intermediate transfer belt 230, and the primary transfer image on the intermediate transfer belt 230 is recorded on the recording medium. Secondary transfer (batch transfer).

In the present embodiment, the secondary transfer device 52 includes a secondary transfer roll 521 arranged in pressure contact with the toner image holding surface side of the intermediate transfer belt 230, and a secondary transfer roll disposed on the back side of the intermediate transfer belt 230. And a rear roll (in this example, also serving as a support roll 232) that forms a counter electrode 521. For example, the secondary transfer roll 521 is grounded, and a bias having the same polarity as the charging polarity of the toner is applied to the back roll (support roll 232).
Furthermore, a belt cleaning device 53 is disposed on the upstream side of the most upstream image forming unit 22a of the intermediate transfer belt 230 to remove residual toner on the intermediate transfer belt 230.

  Further, the recording medium supply cassette 24 is provided with a feeding roll 61 for feeding the recording medium, and immediately after the feeding roll 61, a conveying roll 62 for feeding the recording medium is disposed, and the secondary transfer site A registration roll (positioning roll) 63 for supplying the recording medium to the secondary transfer portion at a predetermined timing is disposed in the recording medium conveyance path 25 positioned immediately before. On the other hand, a fixing device 66 is provided in the recording medium conveyance path 25 located on the downstream side of the secondary transfer site, and a discharge roll 67 for discharging the recording medium is provided on the downstream side of the fixing device 66. The discharged recording medium is accommodated in a paper discharge unit 68 formed on the upper portion of the housing 21.

Further, in the present embodiment, a manual feed device (MSI) 71 is provided on the side of the main body housing 21, and the recording medium on the manual feed device 71 is recorded by the feed roll 72 and the transport roll 62. It is sent out toward the medium conveyance path 25.
Furthermore, the main body housing 21 is provided with a double-sided recording unit 73. The double-sided recording unit 73 discharges the recording medium on which single-sided recording has been performed when the double-sided mode in which image recording is performed on both sides of the recording medium is selected. 67 is reversed and taken in by the guide roll 74 in front of the entrance, transported by the transport roll 77 along the recording medium return transport path 76, and supplied again to the alignment roll 63 side. To do.

Next, the cleaning device 34 disposed in the tandem type image forming apparatus shown in FIG. 3 will be described in detail.
FIG. 4 is a schematic cross-sectional view showing an example of the cleaning device of the present embodiment, and also shows the photosensitive drum 31, the charging roll 32, and the developing unit 33 that are sub-cartridges together with the cleaning device 34 shown in FIG. FIG.
In FIG. 4, 32 is a charging roll (charging device), 331 is a unit case, 332 is a developing roll, 333 is a toner conveying member, 334 is a conveying paddle, 335 is a trimming member, 341 is a cleaning case, 342 is a cleaning blade, 344 Denotes a film seal, 345 denotes a conveying member.

  The cleaning device 34 has a cleaning case 341 that contains residual toner and opens to face the photosensitive drum 31, and a cleaning blade 342 that is disposed in contact with the photosensitive drum 31 at the lower edge of the opening of the cleaning case 341. Is attached via a bracket (not shown), and a film seal 344 is attached to the upper edge of the opening of the cleaning case 341 so that the space between the cleaning drum 341 and the photosensitive drum 31 is kept airtight. Reference numeral 345 denotes a conveying member that guides the waste toner accommodated in the cleaning case 341 to a side waste toner container.

  In the present embodiment, the cleaning blade of this embodiment is used as the cleaning blade 342 in all the cleaning devices 34 of the image forming units 22 (22a to 22d), and the belt cleaning device 53 is used. The cleaning blade 531 may also be the cleaning blade of this embodiment.

Further, the developing unit (developing device) 33 used in the present embodiment has a unit case 331 that accommodates the developer and opens to face the photosensitive drum 31 as shown in FIG. Here, a developing roll 332 is disposed at a position facing the opening of the unit case 331, and a toner conveying member 333 for agitating and conveying the developer is disposed in the unit case 331. Further, a transport paddle 334 may be disposed between the developing roll 332 and the toner transport member 333.
At the time of development, after supplying the developer to the developing roll 332, the developer is conveyed to a developing region facing the photosensitive drum 31 in a state where the thickness of the developer is regulated by the trimming member 335, for example.

  In the present embodiment, as the developing unit 33, for example, a two-component developer composed of toner and carrier is used, but a one-component developer composed only of toner may be used.

Next, the operation of the image forming apparatus according to the present embodiment will be described. First, when each image forming unit 22 (22a to 22d) forms a single color toner image corresponding to each color, the single color toner image of each color is sequentially superimposed on the surface of the intermediate transfer belt 230 so as to coincide with the original document information. Transcribed. Subsequently, the color toner image transferred to the surface of the intermediate transfer belt 230 is transferred to the surface of the recording medium by the secondary transfer device 52, and the recording medium to which the color toner image has been transferred undergoes fixing processing by the fixing device 66. The paper is discharged to a paper discharge unit 68.
On the other hand, in each image forming unit 22 (22a to 22d), residual toner on the photosensitive drum 31 is cleaned by the cleaning device 34, and residual toner on the intermediate transfer belt 230 is cleaned by the belt cleaning device 53. The
In such an image forming process, each residual toner is cleaned by the cleaning device 34 (or the belt cleaning device 53).

  The cleaning blade 342 may be fixed via a spring material instead of being directly fixed to the frame member in the cleaning device 34 as shown in FIG.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited only to these examples. In the following description, “part” means “part by mass”.

[Preparation of thixotropic composition]
(Preparation of thixotropic composition (1))
Surface treated silica particles as inorganic particles in 100 parts of dimethyl silicone oil (DMS300: trade name “KF96-300CS, manufactured by Shin-Etsu Chemical Co., Ltd.” as a lubricant, viscosity characteristic isokinetic viscosity (25 ° C .: 300 mm ² / s) ("PM20 (manufactured by Tokuyama Co., Ltd.)", volume average particle size 12 nm) 7.5 parts was added and stirred to obtain a thixotropic composition (1).

(Thixotropic compositions (2) to (13))
The thixotropic compositions (2) to (13) were prepared by the method described in the thixotropic composition (1) except that the lubricant and the amount thereof, and the inorganic particles and the amount thereof were changed to the compositions shown in Table 1 below. Obtained. However, details of the materials are as follows.
"DMS300": dimethyl silicone oil (trade name "KF96-300CS, manufactured by Shin-Etsu Chemical Co., Ltd.", viscosity property isokinetic viscosity (25 ° C): 300 mm ² / s)
· "DMS100": Dimethyl silicone oil (trade name "KF96-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.", viscosity characteristics Todo viscosity ^{(25 ℃): 100mm 2 /} s)
・ "Liquid paraffin": Trade name "High White 350, JX Nippon Oil & Energy Corporation", kinematic viscosity (25 ° C): 92 mm ² / s
"Surface-treated silica": surface hydrophilized oil-treated silica particles (trade name "PM20, manufactured by Tokuyama Corporation", volume average particle size 12 nm)
・ "Bentonite": Trade name "Bengel Bright 11, Hayashi Kasei Co., Ltd."
・ "Calcium carbonate": Trade name "Calfine N-350,
“Maruo Calcium Co., Ltd.”, volume average particle size 50 nm

[Example 1]
-Cleaning blade A1-
First, polycaprolactone polyol (Daicel Chemical Industries, Plaxel 205, average molecular weight 529, hydroxyl value 212 KOHmg / g) and polycaprolactone polyol (Daicel Chemical Industries, Plaxel 240, average molecular weight 4155, hydroxyl value 27 KOHmg) / G) was used as the soft segment material of the polyol component. Also, an acrylic resin containing two or more hydroxyl groups (Akaflow UMB-2005B, manufactured by Soken Chemical Co., Ltd.) is used as a hard segment material, and the soft segment material and the hard segment material are in a ratio of 8: 2 (mass ratio) Mixed.
Next, 6.26 parts of 4,4′-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MT) is added as an isocyanate compound to 100 parts of the mixture of the soft segment material and the hard segment material. The reaction was performed at 70 ° C. for 3 hours under a nitrogen atmosphere. The amount of isocyanate compound used in this reaction is selected so that the ratio of isocyanate group to hydroxyl group contained in the reaction system (isocyanate group / hydroxyl group) is 0.5.
Subsequently, 34.3 parts of the above isocyanate compound was further added and reacted at 70 ° C. for 3 hours under a nitrogen atmosphere to obtain a prepolymer. The total amount of isocyanate compound used in the use of the prepolymer was 40.56 parts.

  Next, this prepolymer was heated to 100 ° C. and degassed for 1 hour under reduced pressure. Thereafter, 7.14 parts of a mixture of 1,4-butanediol and trimethylolpropane (mass ratio = 60/40) is added to 100 parts of the prepolymer, and 2 parts by weight of the thixotropic composition (1) is added. In addition, the mixture was mixed for 3 minutes so as not to engulf bubbles to prepare a cleaning blade-forming composition A1.

  Next, the cleaning blade forming composition A1 was poured into a centrifugal molding machine whose mold was adjusted to 140 ° C., and a curing reaction was performed for 1 hour. Next, it was aged and heated at 110 ° C. for 24 hours, cooled and then cut to obtain a cleaning blade A1 having a length of 320 mm, a width of 12 mm, and a thickness of 2 mm.

-Thixotropic properties of thixotropic compositions-
Before the test, the thixotropic composition was separated from the cleaning blade by the method described above, and “η (1)” and “η (100)” were measured by the method described above.
The results are shown in Table 1.

[Evaluation test]
The developer shown in Table 2 was charged into a developing device of a modified “700 Digital Color Press” manufactured by FujiXerox, and a cleaning blade shown in Table 2 was mounted as a cleaning blade for the photoreceptor. However, the modified machine includes a cleaning blade having a contact load of 1.6 gf / mm (1.57 N / mm), a contact angle of 10 degrees, a biting amount of 1.0 mm, a blade setting angle of 27.5 degrees, and a free length of 8 mm. It was remodeled as follows.
Using this modified machine, images were output in an environment of 10 ° C./15% RH, and the following tests were performed.

-Ghost evaluation-
In the ghost evaluation, an image with an image density of 30% and an image with a 1% density were alternately output 1000 sheets each, and a total of 100,000 sheets were output. Thereafter, after 1000 images of 1% were output, an image with an image density of 30% was output, and the 20th image was collected.
Then, with respect to the collected output image, the density measurement device (X-rite, Xrite 530) measures and averages the density of the non-image part and the density of the ghost generation part in the non-image part, The difference ΔEL * was determined and ghost evaluation was performed.
The evaluation criteria are as follows.
A: Less than 0.1 B: 0.1 or more and less than 0.3 C: 0.3 or more and less than 0.5 D: 0.5 or more (practical problem)
E: Generation of color streaks due to toner slippage (problematic problems)

-Photoconductor lifetime-
The life of the photoconductor was evaluated by ghost evaluation by measuring the film thickness of the photoconductive layer of the photoconductor after outputting 100,000 sheets and examining the difference from before output.
The evaluation criteria are as follows.
A: 95% or more of initial film thickness B: 90% or more and less than 95% of initial film thickness C: 85% or more and less than 90% of initial film thickness D: Less than 85% of initial film thickness (practical problem) Yes)

-Cleaning blade life-
In the ghost evaluation, the life of the cleaning blade is confirmed by checking the image during output of 100,000 sheets, examining the ghost occurrence state due to the toner or external additive slipping from the cleaning blade, and assigning the ghost occurrence position and the toner slippage occurrence position of the image. Evaluated.
The evaluation criteria are as follows.
A: No ghost or color streaking due to uneven blade wear B: Ghost due to uneven blade wear C: Color streaking of 0.5 mm or less due to blade uneven wear D: Color streaks exceeding 0.5 mm due to blade uneven wear (practical use) There is a problem above)

-Dispersibility of thixotropic composition in cleaning blade-
The dispersibility of the thixotropic composition contained in the cleaning blade was evaluated by the following method.
The light transmittance of the cleaning blade at a wavelength of 700 nm was measured using a spectrophotometer (U-4100, manufactured by Hitachi High-Tech). The transmittance (T1) when the thixo composition was added was measured against the transmittance (T0) 90% when the thixo composition was not added, and the permeation reduction rate (T1 / T0) was evaluated.
The evaluation criteria are as follows.
A: Transmission reduction rate (T1 / T0) 0.9 or more B: Transmission reduction rate (T1 / T0) 0.7 or more and less than 0.9 C: Transmission reduction rate (T1 / T0) less than 0.7

[Examples 2 to 11, Comparative Examples 1 to 3]
Cleaning blades A2 to A11 and CA1 to CA1 were prepared by the method described in Example 1 except that the thixotropic composition used for the production of the cleaning blade and the developer used in the evaluation test were changed to those shown in Table 2 below. CA3 was produced and an evaluation test was performed.

  In Table 2, “-” indicates that the corresponding evaluation test was not performed.

3A contact angle part, 3B front end surface, 3C abdominal surface, 3D back surface, 21 body housing, 22, 22a to 22d image forming unit, 23 belt module, 24 recording medium supply cassette, 25 recording medium transport path, 30 photoconductor unit, 31 Photosensitive drum (image carrier), 32 charging roll, 33 developing unit, 34 cleaning device, 35, 35a to 35d toner cartridge, 40 exposure unit, 41 unit case, 42 polygon mirror, 51 primary transfer device, 52 secondary transfer Device, 53 belt cleaning device, 61 delivery roll, 62 transport roll, 63 positioning roll, 66 fixing device, 67 delivery roll, 68 delivery section, 71 manual feed device, 72 delivery roll, 73 duplex recording unit, 74 guide rolls, 76 transport paths, 77 transport rolls, 30 intermediate transfer belt, 231 and 232 support roll, 331 unit case, 332 developing roll, 333 toner transport member, 334 transport paddle, 335 trimming member, 341 cleaning case, 342, 342A, 342B, 342C cleaning blade, 344 film seal, 345 Conveying member, 521 Secondary transfer roll, 531 Cleaning blade, 3421B First layer, 3422B Second layer, 3421C Contact member, 3422C Back member

Claims (6)

A cleaning blade containing a thixotropic composition satisfying the following formula (A) and containing a lubricant in a region including at least a portion in contact with a member to be cleaned.
Formula (A): η (1) / η (100) ≧ 18
(In formula (A), η (1) indicates the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C. η (100) indicates a temperature of 30 The viscosity (Pa · s) of the thixotropic composition when a shearing force of 100 s ⁻¹ is applied at ° C. is shown.) The cleaning blade according to claim 1, wherein the thixotropic composition satisfies the following formula (B).
Formula (B): 3000 Pa · s ≧ η (1) ≧ 50 Pa · s
(In formula (B), η (1) represents the viscosity (Pa · s) of the thixotropic composition when a shearing force of 1 s ⁻¹ is applied at a temperature of 30 ° C.)   The cleaning blade according to claim 1 or 2, wherein the thixotropic composition contains silica particles obtained by a dry process.   The cleaning apparatus provided with the cleaning blade as described in any one of Claims 1-3. An image carrier,
A charging device for charging the image carrier;
An electrostatic latent image forming apparatus that forms an electrostatic latent image on the surface of the charged image carrier;
A developing device for developing the electrostatic latent image formed on the surface of the image carrier with toner to form a toner image;
A transfer device for transferring a toner image formed on the image carrier onto a recording medium;
The cleaning device according to claim 4, wherein the cleaning blade is brought into contact with the surface of the image carrier after the toner image is transferred by the transfer device, and cleaning is performed.
An image forming apparatus comprising:   A process cartridge comprising the cleaning device according to claim 4 and detachable from the image forming apparatus.