JP5652644B2 - Image forming apparatus, process cartridge - Google Patents

Description

  The present invention relates to an image forming apparatus and a process cartridge.

Conventionally, in an electrophotographic image forming apparatus, unnecessary transfer residual toner adhering to a surface after transferring a toner image to a transfer paper or an intermediate transfer member is cleaned on an image carrier such as a photosensitive member as a member to be cleaned. It is removed by means of a cleaning device.
As a cleaning member of this cleaning device, one that uses a strip-shaped cleaning blade is well known because it can generally be simplified in configuration and has excellent cleaning performance. This cleaning blade is composed of a strip-shaped elastic body such as polyurethane rubber. Then, the base end of the cleaning blade is supported by a support member, and the leading edge portion is pressed against the peripheral surface of the image carrier, and the toner remaining on the image carrier is damped and scraped off and removed.

  Further, in order to meet the recent demand for higher image quality, an image forming apparatus using a toner having a small particle diameter and a nearly spherical shape (hereinafter, polymerized toner) formed by a polymerization method or the like is known. This polymerized toner has characteristics such as higher transfer efficiency than conventional pulverized toner, and can meet the above requirements. However, it is difficult to remove the polymerized toner sufficiently from the surface of the image carrier using a cleaning blade, and there is a problem that cleaning failure occurs. This is because the polymerized toner having a small particle diameter and excellent sphericity passes through a slight gap formed between the blade and the image carrier.

In order to suppress such slip-through, it is necessary to increase the contact pressure between the image carrier and the cleaning blade to enhance the cleaning ability. However, when the contact pressure of the cleaning blade is increased, as shown in FIG. 6A, the frictional force between the image carrier (23) and the cleaning blade (262) is increased, and the cleaning blade (262) is moved to the image carrier. Pulling in the moving direction (23) turns the tip ridge (262c) of the cleaning blade (262).
If the cleaning is continued with the tip edge line portion (262c) of the turned cleaning blade (262) turned up, the tip edge line of the tip surface (262b) of the cleaning blade (262) as shown in FIG. 6 (b). Local wear occurs at a location several [μm] away from the portion (262c). If the cleaning is further continued in such a state, the local wear increases, and finally, the leading edge portion (262c) is lost as shown in FIG. 6C. If the leading edge portion (262c) is missing, the toner cannot be properly cleaned, resulting in poor cleaning.

  Japanese Patent No. 3602898 of Patent Document 1 describes that a surface layer made of a resin having a film hardness of pencil hardness B to 6H is provided on at least a contact portion of a cleaning blade made of polyurethane elastomer. By providing a surface layer having a film hardness of pencil hardness B to 6H that is harder than the rubber member, the friction coefficient of the cleaning blade contact portion can be lowered, and the wear resistance of the cleaning blade can be increased. Further, it is possible to reduce the frictional force between the image carrier and the cleaning blade, and it is possible to satisfactorily suppress the turning of the edge portion of the cleaning blade. Furthermore, since the surface layer of the pencil hardness of pencil hardness B to 6H is hard and hardly deformed, it is possible to further suppress the turning of the tip ridge line portion of the cleaning blade.

Japanese Patent Laid-Open No. 2007-52062 of Patent Document 2 controls the hardness in the vicinity of the surface of the cleaning blade and further sets the difference in hardness between the surface and the inside of the hardened layer to a predetermined condition. High durability and friction resistance are realized by suppressing chipping and turning.
By the way, the present inventors have previously described “a strip-shaped elastic blade, a blade lower surface that is a surface facing the surface of a member to be cleaned, and an end surface of the elastic blade in the longitudinal direction of the elastic blade. It is composed of a surface layer that is harder than the elastic blade and covers the edge of the tip that is a corner with the tip, and the Martens hardness of the elastic blade is 50 [μm] inward in the longitudinal direction of the elastic blade from the tip And 1.0 [N / mm ² ] or more and 5.0 [N / mm ² ] or less at a location 50 [μm] in the direction orthogonal to the longitudinal direction of the elastic blade from the lower surface of the blade, Completed and proposed a “cleaning blade that is 0.4 [N / mm ² ] or more and 0.8 [N / mm ² ] or less” at a location inside 100 [μm] from the surface to the elastic blade length method (see Patent Document 3) (Japanese Patent Application No. 2008-286986) did. The present invention can be said to be a further improvement and development of the proposed technology.

  However, even a cleaning blade provided with a surface layer or a hardened layer may cause poor cleaning under severe conditions such as when a continuous solid image is formed with a very large amount of powder formed on the image carrier. This was confirmed by experiments. This is considered to be due to the following reasons.

  Since the surface layer and the hardened layer are provided over the longitudinal direction of the tip surface of the rubber member, the elasticity of the rubber member is hindered by the influence of the surface layer and the hardened layer, and the tip ridge line portion of the cleaning blade is applied to the surface of the image carrier. Followability is reduced. Therefore, when the image carrier is decentered or there is a minute undulation on the surface of the image carrier, the contact pressure varies. When a large amount of toner is blocked by the cleaning blade, such as during continuous solid image formation, the pressing force to the cleaning blade by the blocked toner is high. For this reason, when the contact pressure of the cleaning blade with the image carrier fluctuates and the contact pressure decreases, the pressing force by the toner exceeds the contact pressure, and the toner slips through the cleaning blade. As a result, it is considered that a cleaning failure has occurred under severe conditions such as during continuous solid image formation in which the amount of powder formed on the image carrier is very large.

  The present invention has been made in view of the above problems, and its purpose is to suppress the turning of the tip ridge line portion and to improve the followability of the tip ridge line portion with respect to the surface of the object to be cleaned and to maintain the contact pressure. A cleaning blade, an image forming apparatus, and a process cartridge are provided.

As a result of intensive studies, the present inventors have found the following.
Observing the occurrence of turning, chipping and wear of the cleaning blade in the range of practical use, these occurred within the range of 20 [μm] on the cut surface and contact surface side from the edge of the tip. The inside of the thickness direction was found to be a phenomenon occurring within 10 [μm] from the cut surface and within 10 [μm] from the contact surface.
Therefore, by controlling the interior within 10 [μm] from the cut surface and within 10 [μm] from the abutting surface, the cleaning blade is not turned and chipped, and the wear resistance is improved. As a result, the present invention has been completed.

That is, in order to solve the above problems, the image forming apparatus and the process cartridge according to the present invention specifically have the technical features described in the following (1) to ( 7 ).
(1) “Image carrier, charging means for charging the surface of the image carrier, latent image forming means for forming an electrostatic latent image on the charged surface of the image carrier, and formed on the surface of the image carrier. A developing means for developing the electrostatic latent image into a toner image; a transfer means for transferring the toner image on the surface of the image carrier to a transfer body; and the image carrier in contact with the surface of the image carrier. In the image forming apparatus including the cleaning unit having a cleaning blade for cleaning the transfer residual toner attached to the surface, the contact tip is cured as the cleaning blade, and the contact tip is perpendicular to the blade member longitudinal direction. The Martens hardness is 0.5 to 1.5 [N / mm at a maximum indentation load of 2 mN at 25 ° C. and 55% at a position of 10 μm from the cut surface and 10 μm from the contact surface in a simple cross section. ^2] Ah is, at the position of the cut surface of the blade member section perpendicular to the longitudinal direction of the contact tip 200 [[mu] m] and 200 [[mu] m] from the contact surface, 25 ° C., at maximum indentation load 2mN in 55% An image forming apparatus using a cleaning blade having a Martens hardness of 0.5 to 1.5 [N / mm ² ] ”,
( 2 ) “Image forming apparatus according to item ( 1 ), wherein the curing process of the cleaning blade is a process in which a surface layer is provided on the contact portion”,
( 3 ) “The Martens hardness of the material used for the surface layer of the cleaning blade is 100 [N / mm ² ] to 600 [N / mm ² ] at a maximum indentation load of 2 mN at 25 ° C. and 55%. The image forming apparatus according to item ( 2 ), wherein:
( 4 ) The item ( 1 ), wherein the surface layer has a layer thickness of 0.2 [μm] to 3 [μm] at a position 10 μm away from the tip ridge line portion of the cleaning blade. Thru | or the image forming apparatus in any one of ( 3 ) term ",
( 5 ) "The image forming apparatus according to any one of ( 1 ) to ( 4 ) above, wherein a treatment for impregnating an isocyanate compound into a tip ridge portion of the cleaning blade is performed",
( 6 ) "Image forming apparatus according to any one of ( 1 ) to ( 5 ), wherein a rubber containing a urethane group is used as a base material of the cleaning blade",
( 7 ) In a process cartridge that integrally supports an image carrier and at least a cleaning unit having a cleaning blade that cleans transfer residual toner attached to the surface of the image carrier and is detachable from the image forming apparatus main body. A process cartridge characterized in that a cleaning blade used in the image forming apparatus according to any one of ( 1 ) to ( 6 ) is used as the cleaning blade.

According to the present invention, the cleaning tip of the contact tip of the cleaning blade is 10 [μm] from the cut surface and 10 [μm] from the contact surface in the cross section perpendicular to the longitudinal direction of the blade member, at 25 ° C. and 55% By setting the Martens hardness at the maximum indentation load of 2 mN within the range of 0.5 to 1.5 [N / mm ² ], the tip wear is suppressed and the followability of the tip edge line portion to the object to be cleaned is improved. It is possible to improve, and it is possible to suppress the wear of the blade and to obtain a good cleaning property.

1 is a schematic configuration diagram illustrating a main part of a printer according to an embodiment of the present invention. It is a figure explaining the definition of the lightness of the toner particles in the present invention. It is a perspective view of the cleaning blade of the present invention. It is an expanded sectional view of the cleaning blade of the present invention. It is a figure which shows the wear width and wear form which saw the braid | blade of this invention from the lower surface side. It is a figure explaining the damage of the cleaning blade front-end | tip part contact | abutted to the member to be cleaned. It is the figure which represented internal Martens hardness from the front-end ridgeline part in Example 1, the comparative example 4, and an untreated goods blade.

(Cleaning blade composition, construction method)
In an elastic blade normally used for a cleaning blade, when the Martens hardness is measured in the vicinity of the surface, it shows a value smaller than the hardness deep inside due to its elastic characteristics like the untreated elastic blade in FIG. This state has been found to be closely related to the blade turning phenomenon, and turning up can be prevented by increasing the hardness in the vicinity of the surface. That is, when the maximum indentation load is 2 mN at 25 ° C. and 55% within 10 μm from the cut surface and 10 μm from the contact surface in the cross section perpendicular to the blade member longitudinal direction of the elastic blade contact tip. When the Martens hardness is 0.5 to 1.5 [N / mm ² ], it is difficult to turn the tip ridge line portion, and the wear resistance can be increased. When the Martens hardness is less than 0.5 (N / mm ² ), turning is likely to occur, and when it is higher than 1.5 (N / mm ² ), the rigidity is increased and the blade is likely to be chipped. Examples of means for setting the range of the Martens hardness include, but are not limited to, a surface layer or an impregnation layer provided in the vicinity of the contact tip of the base elastic blade.
In addition, in order to ensure adhesion and followability between the cleaning blade and the surface of the member to be cleaned, an elastic body is desirable as a physical property of the entire cleaning blade. It is preferable that the Martens hardness is 0.5 to 1.5 [N / mm ² ] when the maximum indentation load is 2 mN at 25 ° C. and 55% within 200 [μm] and 200 [μm] from the contact surface. . If the Martens hardness is 0.5 [N / mm ² ] or less, it is too soft and tends to be turned over, and if it is 1.5 [N / mm ² ] or more, adhesion and followability cannot be ensured. .

<Matrix elastic body blade>
The elastic blade used for the base body can be manufactured by a generally known composition and construction method. FIG. 3 is a perspective view of the cleaning blade (62), and FIG. 4 is an enlarged sectional view of the cleaning blade (62).

  The cleaning blade (62) includes a strip-shaped holder (621) made of a rigid material such as metal or hard plastic, and a strip-shaped elastic blade (622). The elastic blade (622) is fixed to one end of the holder (621) with an adhesive or the like, and the other end of the holder (621) is cantilevered by the case of the cleaning device (6). The elastic blade (622) preferably has a high resilience rate so that it can follow the eccentricity of the photosensitive member (3), minute undulations on the surface of the photosensitive member, etc., and urethane which is a rubber containing a urethane group Rubber or the like is preferred.

  In general, polyurethane elastomers are prepared by using, for example, polyethylene adipate ester or polycaprolactone ester as a polyol component and 4,4′-diphenylmethane diisocyanate as a polyisocyanate component, and a curing agent and, if necessary, a catalyst. Is added, and is crosslinked in a predetermined mold, post-crosslinked in a furnace, and then allowed to mature at room temperature. At least one of the polyisocyanate component and the polyol component is preferably an aromatic material.

  As the high molecular weight polyol, for example, a polyester polyol which is a condensate of an alkylene glycol and an aliphatic dibasic acid, for example, ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene Polyester polyols such as butylene adipate ester polyol, polyester glycols of alkylene glycol and adipic acid such as ethylene neopentylene adipate ester polyol, polycaprolactone polyols such as polycaprolactone ester polyol obtained by ring-opening polymerization of caprolactone, Poly (oxy (tetramethylene) glycol, poly (oxypropylene) glycol, etc. Ether-based polyols, or the like is used.

  Other low molecular weight polyols include, for example, 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis (2-hydroxyethyl) ether, 3,3′-dichloro-4,4′-diaminodiphenyl. Dihydric alcohols such as methane, 4,4'-diaminodiphenylmethane, 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylol Mention may be made of trihydric and higher polyhydric alcohols such as ethane, 1,1,1-tris (hydroxyethoxymethyl) propane, diglycerin, pentaerythritol.

  Specific examples of the curing catalyst include 2-methylimidazole and 1,2-dimethylimidazole, and 1,2-dimethylimidazole is particularly preferably used. Such a catalyst is usually used in an amount of 0.01 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, based on 100 parts by weight of the main agent.

<Surface layer>
When the maximum indentation load is 2 mN at 25 ° C. and 55% within 10 [μm] from the cut surface and 10 [μm] from the contact surface in the cross section perpendicular to the blade member longitudinal direction at the contact tip of the cleaning blade. A surface layer (623) can be provided to make the Martens hardness 0.5 to 1.5 [N / mm ² ]. The surface layer (623) is formed on the tip edge line portion (62c) of the cleaning blade (62) by spray coating, dip coating, screen printing, or the like.

  The material of the surface layer (623) is preferably a resin, and examples of the resin include, but are not limited to, an acrylic resin, a lactone-modified acrylic urethane, an acrylic silicone, a thermoplastic urethane, and a phenol resin. It is not a thing. Among the resins, an ultraviolet curable resin is more preferable. By using the ultraviolet curable resin, the surface layer (623) having a desired hardness can be obtained simply by irradiating the resin adhering to the tip ridge (62c) of the cleaning blade (62) with ultraviolet rays. (62) can be manufactured at low cost.

Further, as the material of the surface layer, it is possible to control the hardness inside the blade to an appropriate range by using a material having a Martens hardness of 100 to 600 (N / mm ² ) when the maximum load is 2 mN. More preferably, it is 150-350 (N / mm < ² >). When the Martens hardness is less than 100 (N / mm ² ), the hardness inside the blade is the same as when the surface layer is not provided, and the blade is easily turned over. When the hardness is higher than 600 (N / mm ² ), the rigidity is increased. The blade becomes stronger and the chipping of the blade tends to occur, and the wear resistance deteriorates.

  Further, by setting the thickness of the surface layer (623) to 0.2 to 3 [μm], it is possible to control the hardness inside the blade to an appropriate range, and more preferably 0.5 to 1 .5 [μm]. If the layer thickness is less than 0.1, the blade is not easily turned over, and if it is larger than 3 [μm], the rigidity is increased and the blade is likely to be chipped. Abrasion deteriorates.

<Impregnated layer>
When the maximum indentation load is 2 mN at 25 ° C. and 55% within 10 [μm] from the cut surface and 10 [μm] from the contact surface in the cross section perpendicular to the blade member longitudinal direction at the contact tip of the cleaning blade. An impregnated layer can be provided to make the Martens hardness 0.5 to 1.5 [N / mm ² ]. Further, the impregnation layer may be provided together with the surface layer.

  The impregnation treatment to the tip ridge line portion (62c) of the elastic blade (622) can be performed by impregnating an isocyanate compound, an acrylic resin, or the like by spray coating, dip coating, or the like.

<Image forming apparatus>
Next, an embodiment in which the present invention is applied to an electrophotographic printer (hereinafter simply referred to as a printer) as an image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram illustrating a main part of the printer according to the present embodiment. The printer performs single color copying, and forms a monochrome image based on image data read by an image reading unit (not shown).

  As shown in FIG. 1, the printer includes a drum-shaped photoconductor (3) as an image carrier. The photoconductor (3) has a drum shape, but may be a sheet or endless belt.

  Around the photoreceptor (3), there are a charging device (4) as a charging means, a developing device (5) as a developing means for converting the latent image into a toner image, and a transfer means for transferring the toner image onto a transfer sheet as a recording medium. As a transfer device (7), a cleaning device (6) as a cleaning means for cleaning toner remaining on the photoreceptor (3) after transfer, and a lubricant application means for applying a lubricant on the photoreceptor (3). A lubricant application device (10), a static elimination lamp (not shown) for neutralizing the photosensitive member (3), and the like are arranged.

  The charging device (4) is disposed in a non-contact manner with a predetermined distance from the photoconductor (3), and charges the photoconductor (3) to a predetermined polarity and a predetermined potential. The photosensitive member (3) uniformly charged by the charging device (4) is irradiated with light (L) based on image data from an exposure device which is a latent image forming means (not shown) to form an electrostatic latent image.

The developing device (5) has a developing roller (51) as a developer carrier. A developing bias is applied to the developing roller (51) from a power source (not shown).
In the casing of the developing device (5), a supply screw (52) and a stirring screw (53) are provided for stirring the developer contained in the casing while conveying the developer in opposite directions. A doctor (54) for regulating the developer carried on the developing roller (51) is also provided. The toner in the developer stirred and conveyed by the two screws of the supply screw (52) and the stirring screw (53) is charged to a predetermined polarity. Then, the developer is pumped up to the developing roller (51), and the pumped-up developer is regulated by the doctor (54), and the toner is transferred onto the photosensitive member (3) in the developing region facing the photosensitive member (3). Adhere to the latent image.

  The cleaning device (6) includes a fur brush (101), a cleaning blade (62), and the like. The cleaning blade (62) is in contact with the photoconductor (3) in the counter direction with respect to the surface movement direction of the photoconductor (3). The details of the cleaning blade (62) will be described later.

The lubricant application device (10) includes a solid lubricant (103), a lubricant pressure spring (not shown), etc., and a fur brush as an application brush for applying the solid lubricant (103) onto the photoreceptor (3). (101) is used. The solid lubricant (103) is held by a bracket (not shown) and is pressed toward the fur brush (101) by a lubricant pressurizing spring (not shown).
Then, the solid lubricant (103) is shaved by the fur brush (101) that rotates in the rotational direction with respect to the rotation direction of the photoconductor (3), and the lubricant is applied onto the photoconductor (3). By applying the lubricant to the photoconductor, the coefficient of friction of the photoconductor surface is maintained at 0.2 or less during non-image formation.

For the charging device (4), known means such as a corotron, a scorotron, a solid state charger (solid state charger) are used.
Among these charging methods, the contact charging method or the non-contact proximity arrangement method is more desirable, and has advantages such as high charging efficiency, a small amount of ozone generation, and miniaturization of the apparatus.

In addition, light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescences (ELs) are used as light sources such as exposure apparatuses and static elimination lamps (not shown). General can be used.
In addition, various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

  Among these light sources, a light emitting diode and a semiconductor laser have high irradiation energy and have a long wavelength light of 600 to 800 [nm], so that they are used favorably.

Next, an image forming operation in the printer will be described.
When a print execution signal is received from an operation unit (not shown) or the like, a predetermined voltage or current is sequentially applied to the charging device (4) and the developing roller (51) at predetermined timing. Similarly, a predetermined voltage or current is sequentially applied to the exposure apparatus and the charge removal lamp at predetermined timing. In synchronization with this, the photosensitive member (3) is rotationally driven in the direction of the arrow in the figure by a photosensitive member driving motor (not shown) as a driving means.

  When the photoreceptor (3) rotates in the direction of the arrow in the figure, the surface of the photoreceptor is first charged to a predetermined potential by the charging device (4). Then, light (L) corresponding to the image signal is irradiated onto the photoconductor (3) from an exposure apparatus (not shown), and the portion of the photoconductor (3) irradiated with the light (L) is neutralized, and an electrostatic latent image is obtained. Is formed.

  The photosensitive member (3) on which the electrostatic latent image is formed is rubbed against the surface of the photosensitive member (3) with a developer magnetic brush formed on the developing roller (51) at a portion facing the developing device (5). Is done. At this time, the negatively charged toner on the developing roller (51) is moved to the electrostatic latent image side by a predetermined developing bias applied to the developing roller (51), and is formed into a toner image (development). As described above, in this embodiment, the electrostatic latent image formed on the photoreceptor (3) is reversely developed with the negatively charged toner by the developing device (5). In this embodiment, an example using a non-contact charging roller system of N / P (negative positive: toner adheres to a place where the potential is low) has been described, but the present invention is not limited to this.

  The toner image formed on the photosensitive member (3) is formed between the photosensitive member (3) and the transfer device (7) from a paper feeding unit (not shown) through an opposing portion of the upper registration roller and the lower registration roller. Is transferred to a transfer sheet fed to the transfer area. At this time, the transfer paper is supplied in synchronism with the leading edge of the image at the facing portion between the upper registration roller and the lower registration roller. In addition, a predetermined transfer bias is applied during transfer onto the transfer paper. The transfer paper onto which the toner image has been transferred is separated from the photoreceptor (3) and conveyed to a fixing device (not shown) as fixing means. By passing through the fixing device, the toner image is fixed on the transfer paper by the action of heat and pressure, and the transfer paper is discharged out of the apparatus.

  On the other hand, the surface of the photoreceptor (3) after the transfer is subjected to the removal of residual toner after the transfer by the cleaning device (6), the lubricant is applied by the lubricant application device (10), and then the charge is eliminated by the charge eliminating lamp. The

  In the printer, the photosensitive member (3) and the charging device (4), the developing device (5), the cleaning device (6), the lubricant applying device (10), and the like as process means are provided on the frame (2). The process cartridge (1) is detachably integrated with the apparatus main body. In this embodiment, the photosensitive member (3) as the process cartridge (1) and the process means are integrally replaced. However, the photosensitive member (3), the charging device (4), and the developing device are replaced. (5) It is also possible to replace the unit with a new unit such as the cleaning device (6) and the lubricant application device (10).

Next, a toner suitable for the printer will be described.
As the toner used in the printer, it is preferable to use a polymerized toner produced by a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method, which can easily increase the circularity and reduce the particle size in order to improve the image quality.
In particular, it is preferable to use a polymerized toner having a circularity of 0.97 or more and a volume average particle size of 5.5 [μm] or less. By using a material having an average circularity of 0.97 or more and a volume average particle size of 5.5 [μm], a higher resolution image can be formed.

  The “circularity” here is an average circularity measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). Specifically, in 100 to 150 [ml] of water from which impure solids have been removed in advance in a container, 0.1 to 0.5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, Further, about 0.1 to 0.5 [g] of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes so that the concentration of the dispersion becomes 3000 to 1 [10,000 / μl]. To measure the shape and distribution of the toner. Based on the measurement result, the outer peripheral length of the actual toner projection shape shown in FIG. 2A is C1, and the projection area is S. The outer circumference of the perfect circle shown in FIG. C2 / C1 was determined when the length was C2, and the average value was defined as the circularity.

The volume average particle diameter can be determined by a Coulter counter method.
Specifically, the toner number distribution and volume distribution data measured by the Coulter Multisizer 2e type (manufactured by Coulter) are sent to a personal computer via an interface (manufactured by Nikkaki Co., Ltd.) for analysis. More specifically, a 1% NaCl aqueous solution using first grade sodium chloride is prepared as an electrolytic solution. Then, 0.1 to 5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Further, 2 to 20 [mg] of toner as a test sample is added thereto, and the dispersion treatment is performed for about 1 to 3 minutes using an ultrasonic disperser. Then, 100 to 200 [ml] of the electrolytic aqueous solution is put into another beaker, and the solution after the dispersion treatment is added to the beaker so as to have a predetermined concentration, and then applied to the Coulter Multisizer 2e type. The aperture is 100 [μm], and the particle size of 50,000 toner particles is measured. As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], toner particles with a particle size of 2.00 [μm] or more and 32.0 [μm] or less are targeted. Then, the volume average particle diameter is calculated based on the relational expression “volume average particle diameter = ΣXfV / ΣfV”. However, X is the representative diameter in each channel, V is the equivalent volume in the representative diameter of each channel, and f is the number of particles in each channel.

Next, a verification experiment conducted by the present inventors will be described.
The durability test was performed by changing the material, layer thickness, and impregnation treatment of the surface layer (623).

[Matrix elastic blade]
As the elastic blade (622), a cleaning blade made of polyurethane used in Ricoh's imgio Neo C4500 was used.

[Surface layer]
A surface layer was formed at the contact tip by spray coating. The spray device is PC-308WIDE made by Olympus, and the spray gun is moved at a speed of 10 [mm / s] at a pressure of 0.5 [MPa] from a distance of 40 [mm] from the contact tip. However, the coating amount was adjusted so that the layer thickness of the following examples was adjusted. Thereafter, pre-drying was performed at 50 ° C. for 5 minutes, and ultraviolet irradiation (1000 mJ / cm ² ) was performed. In addition, the Martens hardness of the surface layer material was measured at a maximum load of 2 mN using a HM-2000 manufactured by Fisher and coated with the surface layer material by the above-described production method so that the layer thickness was 20 μm. The surface layer materials used in this verification experiment are as follows.

(Surface layer material 1)
KAYARAD DPCA-120 manufactured by Nippon Kayaku Co., Ltd .: 20 parts Ciba Chemical Co., Ltd. I-184: 1 part 2-butanol: 79 parts Martens hardness: 150 N / mm ²

(Surface layer material 2)
KAYARAD TMPTA manufactured by Nippon Kayaku Co., Ltd .: 20 parts Ciba Chemical Co., Ltd. I-184: 1 part 2-butanol: 79 parts Martens hardness: 350 N / mm ²

(Surface layer material 3)
KAYARAD R-526 manufactured by Nippon Kayaku Co., Ltd. 20 parts Ciba Chemical Co. I-184: 1 part 2-butanol: 79 parts Martens hardness: 70 N / mm ²

[Impregnation layer]
An impregnation layer was formed at the contact tip by dip coating. The range from the tip ridge line portion of the cleaning blade to 2 mm was immersed in an impregnating agent for a predetermined time, and then taken out and wiped off with a nonwoven fabric in which the impregnating agent at the tip ridge line portion was immersed in a solvent.
Thereafter, pre-drying was performed at 100 ° C. for 10 minutes, and aging was performed at 35 ° C. and 85% for 7 hours. The following materials were used as the impregnating agent.

(Impregnating agent 1)
Isocyanate compound Nippon Polyurethane MR-100: 20 parts Solvent 2-butanone: 70 parts Examples 1-4 and Comparative Examples 1-4 were prepared as described below using the above surface layer material and impregnating agent. Further, the Martens hardness inside the produced cleaning blade was measured as follows. The observation sample was cut at a maximum load of 2 mN using a Fisher HM-2000 by cutting a cross section using a trimming razor for SEM sample preparation manufactured by Nisshin EM.

Surface layer material 1
Layer thickness: 3μm
Martens hardness within 10 [μm] from the tip: 0.7 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

Surface layer material 2
Layer thickness: 1μm
Martens hardness within 10 [μm] from the tip: 1.0 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

Surface layer material 2
Layer thickness: 0.2μm
Martens hardness within 10 [μm] from the tip: 0.5 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

Impregnating agent 1
Impregnation time: 5 min
Martens hardness within 10 [μm] from the tip: 1.5 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

[Comparative Example 1]
Martens hardness within 10 [μm] from the tip of the untreated product: 0.2 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

[Comparative Example 2]
Surface layer material 1
Layer thickness: 0.1 μm
Martens hardness within 10 [μm] from the tip: 0.2 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

[Comparative Example 3]
Surface layer material 3
Layer thickness: 1μm
Martens hardness within 10 [μm] from the tip: 0.2 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

[Comparative Example 4]
Surface layer material 2
Layer thickness: 4μm
Martens hardness within 10 [μm] from the tip: 2.5 [N / mm ² ]
Martens hardness within 200 [μm] from the tip: 0.8 [N / mm ² ]

Next, the configuration of the image forming apparatus in which the verification experiment was performed will be described.
The above-mentioned cleaning blade was attached to a Ricoh color composite machine image Neo Neo C4500, and image forming apparatuses of Examples 1 to 4 and Comparative Examples 1 to 4 were produced. As the toner, a toner prepared by a polymerization method was used. The physical properties of the toner are as follows.
Toner base: circularity 0.98, average particle size 4.9 [μm]
External additive Small particle size silica: 1.5 parts (H2000 manufactured by Clariant)
Small particle size titanium oxide: 0.5 part (MT-150AI manufactured by Teika)
Large particle size silica: 1.0 part (UFP-30H manufactured by Denki Kagaku Kogyo Co., Ltd.)

  The verification experiment was performed in a laboratory environment: 21 [° C.] and 65 [% RH], a sheet passing condition: an image area ratio 5% chart at 3 prints / jobs at 50,000 sheets (A4 landscape). And the following items were evaluated.

[Evaluation item]
Occurrence of cleaning failure: Existence (visual observation)
Evaluation image: Vertical belt pattern (with respect to the paper traveling direction) 43 [mm] width, 3 chart output 20 sheets (A4 landscape)
Blade edge wear width and wear form: Wear width and wear form as seen from the blade lower surface as shown in FIG.

The result of the verification experiment of the cleaning blade of Examples 1 to 4 and Comparative Examples 1 to 4 is shown below. In addition, the layer thickness of the surface layer was measured by a cross section of an elastic blade separately coated in the same manner using a microscope VHX-100 manufactured by Keyence Corporation.
The sample was a cross-section cut using a trimming razor for SEM sample preparation manufactured by Nisshin EM.

The above Table 1 summarizes the results of verification experiments of Examples 1 to 4 and Comparative Examples 1 to 4.
In each of Examples 1 to 4, good cleaning properties could be maintained over time. In addition, although the wear type was also untreated, Comparative Example 1 caused pitting, but Examples 1 to 4 did not cause pitting, and the wear was clean from the edge. Further, the wear width was smaller than that of the untreated product, and it was confirmed that the wear resistance was improved. On the other hand, in Comparative Examples 2 to 3, chipping occurred similarly to the untreated product, and the wear width was at the same level as the untreated product. Further, in Comparative Example 4, many chips were generated, and the cleaning property was greatly deteriorated.

As described above, according to the present embodiment, the Martens hardness is set to 0.5 to 10 [μm] from the cut surface and 10 [μm] from the contact surface in the cross section perpendicular to the blade member longitudinal direction of the contact tip portion. As is clear from the above-described verification experiment, by setting the range to 1.5 [N / mm ² ], it is possible to maintain good cleaning properties, and the tip edge line portion is turned up to suppress chipping. It is possible to improve wear resistance.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Frame 3 Photoconductor 4 Charging device 5 Developing device 6 Cleaning device 7 Transfer device 8 Backup roller 10 Lubricant coating device 14 Transfer belt 51 Developing roller 52 Supply screw 53 Stirring screw 54 Doctor 62 Cleaning blade 62a Front end surface 62b Blade lower surface 62c Tip edge portion 101 Fur brush 103 Solid lubricant 262 Cleaning blade 262a Tip surface 262b Blade lower surface 262c Tip edge portion 621 Holder 622 Elastic blade 623 Surface layer

Japanese Patent No. 3602898 JP 2007-52062 A Japanese Patent Application No. 2008-286986

Claims (7)

An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the charged surface of the image carrier, and the electrostatic formed on the surface of the image carrier. A developing unit that develops a latent image into a toner image, a transfer unit that transfers a toner image on the surface of the image carrier to a transfer body, and abuts on the surface of the image carrier and adheres to the surface of the image carrier In the image forming apparatus provided with a cleaning unit having a cleaning blade for cleaning the transfer residual toner, the contact tip is cured as the cleaning blade, and the contact tip is cut in a cross section perpendicular to the longitudinal direction of the blade member. The Martens hardness is 0.5 to 1.5 [N / mm ² ] at a maximum indentation load of 2 mN at 25 ° C. and 55% at a position of 10 μm from the surface and 10 μm from the contact surface. The The Martens hardness is 0 at a maximum indentation load of 2 mN at 25 ° C. and 55% at a position of 200 μm from the cut surface and 200 μm from the contact surface in the cross section perpendicular to the longitudinal direction of the blade member at the contact tip. An image forming apparatus using a cleaning blade of 5 to 1.5 [N / mm ² ] . The image forming apparatus according to claim 1 , wherein the curing process of the cleaning blade is a process in which a surface layer is provided on the contact portion. The Martens hardness of the material used for the surface layer of the cleaning blade is 100 [N / mm ² ] to 600 [N / mm ² ] at a maximum indentation load of 2 mN at 25 ° C. and 55%. The image forming apparatus according to claim 2 . According to the layer thickness of the surface layer at a position apart 10μm from the edge line of the cleaning blade, 0.2 [μm] ~3 [μm ] any of claims 1 to 3, characterized in that it is Image forming apparatus. The image forming apparatus according to any one of claims 1 to 4, characterized in that the process of impregnating the isocyanate compound have been made to the front edge portion of the cleaning blade. The image forming apparatus according to any one of claims 1 to 5, characterized by using a rubber containing urethane groups as the base material of the cleaning blade. In a process cartridge that integrally supports an image carrier and at least a cleaning unit having a cleaning blade that cleans transfer residual toner attached to the surface of the image carrier, and is detachable from the image forming apparatus main body, , the process cartridge characterized by using a cleaning blade used in the image forming apparatus according to any one of claims 1 to 6.

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