JP2016148791A - Cleaning blade, image formation apparatus and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade which can suppress increase in abrasion especially under a low temperature environment, suppress peeling-off of a tip ridge portion while suppressing the occurrence of abnormal abrasion and abnormal sound, improve the followability to a cleaning object member of the tip ridge portion and maintain the uniform cleaning performance over a long period of time.SOLUTION: A cleaning blade includes an elastic blade and removes a residual material adhering to a cleaning object member surface from the surface of a cleaning object member contacting the tip ridge portion of the elastic blade. The elastic blade includes a base material and a surface layer formed on the surface including a tip ridge portion of the base material. The base material is composed of urethane rubber having an equilibrium swelling constant of 200% or more at the time of being immersed in cyclohexanone, and has a mixed layer of the urethane rubber and acryl/methacryl resin in a portion including the tip ridge portion. The surface layer consists of acryl/methacryl resin and is formed in a region including the entire tip surface of the base material and the tip ridge portion of the lower surface of the base material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cleaning blade, 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. 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.

In addition, the image forming apparatus forms an image by transferring the obtained toner image onto a sheet, heat-melting and fixing. In this fixing process, since a large amount of electric power is required to heat and melt the toner, a low-temperature fixing toner containing a crystalline resin as a binder resin is used from the viewpoint of energy saving.
In such a low-temperature fixable toner, proposals have been made to control the thermal characteristics of the crystalline resin in order to achieve both heat resistance.
By controlling the thermal characteristics of the crystalline resin, even if frictional heat is generated during cleaning, it is possible to reduce cleaning defects accompanying melting of the toner to some extent.

  However, when a large pressure is applied to the toner by the cleaning member, the crystalline layer of the crystalline resin contained in the toner is displaced and deformed, so that the deformed toner easily slips between the cleaning member and the photosensitive member. As a result, if the slipped toner adheres to the surface of the photoreceptor in the form of a film, the image quality is affected.

  In addition, the cleaning blade made of an elastic body causes a so-called stick-slip motion in which the ridge line repeatedly deforms during sliding with the image carrier, so that a toner having a small particle size and a nearly spherical shape formed by a polymerization method or the like ( Hereinafter, the polymerized toner) passes through a slight gap formed between the blade and the image carrier. At this time, the low-temperature fixable toner using the crystalline resin is crushed and fused to the surface of the elastic blade to lower the cleaning function, or fused to the surface of the image carrier to cause an image defect. .

  As a result of intensive studies in view of the above problems, the inventors of the present invention disclosed in Patent Document 1 that the portion including the tip ridge line portion of the elastic blade was impregnated with acrylic / methacrylic resin and the elasticity including the tip ridge line portion. A cleaning blade was proposed in which a surface layer harder than the elastic blade was provided on the surface of the blade.

  In the conventional cleaning blade, a surface layer harder than the elastic blade is provided on the surface including the tip ridge portion, and the portion including the tip ridge portion is impregnated with acrylic / methacrylic resin so that the blade slides on the image carrier. The stick slip at the time can be reduced to the limit. As a result, the followability to the image carrier of the tip ridge line portion is improved, and when using a low-temperature fixability toner containing a crystalline resin capable of low-temperature fix as well as suppressing toner slipping, Even if the toner slips through, the low-temperature fixing toner that is easily deformed can be prevented from being crushed and deformed.

  However, nano-silica having a thickness of several nanometers, which has been used with the recent reduction in the particle size of polymerized toner, has a problem of promoting ridge wear of the cleaning blade. In particular, in a low temperature environment such as winter, the amount of nanosilica falling from the inside of the toner increases in the cleaning process, and this accumulates on the ridgeline of the cleaning blade and greatly wears the cleaning blade as it slips through.

  The present invention has been made in view of the above background, and its purpose is to suppress the increase in wear of the cleaning blade, particularly in a low-temperature environment, and to turn up the tip ridge line portion while suppressing the occurrence of abnormal wear and abnormal noise. It is an object of the present invention to provide a cleaning blade that can suppress and improve the followability of a tip ridge line portion to a member to be cleaned and can maintain a uniform cleaning performance over a long period of time.

Furthermore, as a result of the study by the present inventors, it has been found that the rubber characteristics of the elastic blade and the characteristics of the ultraviolet curable resin impregnated in the elastic blade are important.
To achieve the above object, the present invention provides:
A cleaning blade that has an elastic blade and removes residue adhered to the surface of the member to be cleaned from the surface of the member to be cleaned that is in contact with the tip ridge line portion of the elastic blade,
The elastic blade is composed of a base material and a surface layer formed on a surface including a tip ridge portion of the base material,
The base material is composed of urethane rubber having an equilibrium swelling ratio of 200% or more when immersed in cyclohexanone,
Having a mixed layer of the urethane rubber and acrylic / methacrylic resin in a portion including the tip ridge line portion of the substrate;
The surface layer is made of acrylic / methacrylic resin, and is formed in a region including the entire front end surface of the base material and the front end ridge line portion of the lower surface of the base material.

  The cleaning blade according to the present invention allows the elastic blade to perform an appropriate stick-slip motion even when used over time, thereby suppressing wear on the ridgeline particularly in a low temperature environment and suppressing the generation of abnormal noise, and uniform over a long period of time. It has an excellent effect that it is possible to exhibit a good cleaning performance.

FIG. 4 is an enlarged cross-sectional view of a cleaning blade according to the present invention, (a) is an explanatory view showing a state in which the cleaning blade is in contact with the surface of the photosensitive member, and (b) is an enlarged illustration of the vicinity of the tip ridge line portion 62c of the cleaning blade 62. Figure. 1 is a schematic configuration diagram of a printer according to the present invention. 1 is a schematic configuration diagram of an image forming unit according to the present invention. (A) And (b) is explanatory drawing for demonstrating the measuring method of the circularity of a toner. The perspective view of the cleaning blade which concerns on this invention. The conceptual diagram which compares the cleaning blade of an Example and a comparative example. (A) is a diagram showing a state in which the leading edge portion of the cleaning blade is turned up, (b) is a diagram for explaining local wear on the leading end surface of the cleaning blade, and (c) is a diagram showing the leading edge portion of the cleaning blade. The figure which shows the state missing. The schematic diagram which showed the measurement location of the abrasion cross-sectional area of the elastic blade based on an Example.

The cleaning blade according to the present invention is a cleaning blade having an elastic blade, which removes residues adhering to the surface of the member to be cleaned from the surface of the member to be cleaned that is in contact with the tip ridge line portion of the elastic blade. Is composed of a base material and a surface layer formed on the surface including the tip ridge portion of the base material, and the base material is made of urethane rubber having an equilibrium swelling ratio of 200% or more when immersed in cyclohexanone. The urethane rubber and an acrylic / methacrylic resin mixed layer are included in the portion including the tip ridge line portion of the base material, the surface layer is made of acrylic / methacrylic resin, and the whole tip surface of the base material and the base material It is formed in the area | region containing the front-end | tip ridgeline part of the lower surface.
In the present invention, the surface in the longitudinal direction of the base material constituting the elastic blade and facing the member to be cleaned is referred to as the lower surface of the base material, and the front surface including the tip ridge line portion of the base material is referred to as the front surface.
In addition, the surface in the longitudinal direction of the elastic blade that faces the member to be cleaned is referred to as a blade lower surface, and the tip surface including the tip ridge line portion of the elastic blade is referred to as a blade tip surface.

As the base material of the elastic blade, urethane rubber having an equilibrium swelling ratio of 200% or more when immersed in cyclohexanone in a normal temperature environment is used. Those that do not satisfy this condition have a high crosslinking density of the rubber, so that it is difficult to quickly impregnate the acrylic / methacrylic resin, and a sufficient modification effect cannot be obtained. Further, since the rigidity of the non-impregnated portion is high, the contact with the image carrier becomes too strong, and a great amount of ridge line wear occurs at an early stage, thereby deteriorating the cleaning performance. The equilibrium swelling ratio when urethane rubber is immersed in cyclohexanone in a room temperature environment is preferably 200 to 300%.
In the present invention, the base material has a mixed layer of an acrylic / methacrylic resin and urethane rubber obtained by impregnating a monomer material that becomes an acrylic / methacrylic resin into a portion including a tip ridge line portion and curing with ultraviolet rays. By forming a resin network chain inside the rubber, it is considered that the crosslink density of the rubber itself increases in a pseudo manner and wear resistance is improved.
Then, a surface layer of acrylic / methacrylic resin is formed on the entire surface of the blade tip including the tip ridge line portion, and on the lower surface of the blade including the tip ridge line portion. Due to the effect of the rigid surface layer, the elastic blade is not easily deformed, and the leading edge portion of the cleaning blade can be prevented from being pulled in and stick-slip motion can be suppressed.
As for the lower surface of the blade, the surface layer is preferably in a range of 2 mm or more including the tip ridge line portion, and the surface layer may be formed on the entire surface of the blade lower surface, but is formed in a range of about 5 mm including the tip ridge line portion. Is more preferable.

The mixed layer of acrylic / methacrylic resin and urethane rubber is preferably in a range from the surface to the inside of 50 to 300 μm. If the depth from the surface of the mixed layer is too small, even if it is modified by the mixed layer and the surface layer is formed on the surface, the durability performance is not sufficient, and the wear of the ridge line part is greatly increased by long-term use. As a result, there is a possibility that the cleaning performance is deteriorated. On the other hand, if the depth of the mixed layer is too large, the tip ridge line portion becomes too rigid, which may cause an increase in wear particularly in a low temperature environment. On the other hand, in the urethane rubber having a mixed layer that satisfies the above conditions, an acrylic / methacrylic resin is efficiently contained in the tip ridge line portion to obtain a sufficient modification effect, and a surface layer is formed on the surface thereof. Good wear resistance can be improved.
The thickness of the mixed layer can be determined by measuring the cross section of the elastic blade with microscopic IR. The microscopic IR apparatus can be measured using FT / IR-6200 (attached to IRT-7000) manufactured by JASCO Corporation. A cross-sectional slice of the elastic blade is cut out, the section is fixed on a Si wafer, and the cross-section can be measured by microscopic IR. In the microscopic IR method, it is preferable to measure by the ATR method. For example, when an acrylic resin is used as the curable resin, it can be confirmed that the acrylic is impregnated to the portion where the peak of the spectrum 810 cm ⁻¹ due to the unreacted acrylic group (C═C) exists.

Further, by using the urethane rubber, it is possible to obtain the maximum effect of improving the wear resistance by the impregnation and ultraviolet curing. This is presumably because the pseudo-crosslinked structure in the mixed layer of acrylic / methacrylic resin and urethane rubber expresses an appropriate balance in the urethane rubber having the above characteristics. The acrylic / methacrylic resin forming this mixed layer is preferably obtained by using an acrylic material containing an alicyclic acrylate monomer having at least a functional group equivalent molecular weight of 200 or less and a functional group number of 2 and can appropriately modify rubber. It becomes possible.
The alicyclic acrylate monomer having a functional group equivalent molecular weight of 200 or less and a functional group number of 2 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimer Examples include (meth) acrylate compounds having a tricyclodecane structure such as methacrylate. As the (meth) acrylate compound having the tricyclodecane structure, an appropriately synthesized compound or a commercially available product may be used. As this commercial item, brand name: A-DCP (made by Shin-Nakamura Chemical Co., Ltd.) etc. are mentioned, for example.
The acrylic / methacrylic resin forming the mixed layer preferably contains at least 90% of an alicyclic acrylate monomer having a functional group equivalent molecular weight of 200 or less and a functional group number of 2.

The mixed layer is preferably formed on the entire blade tip surface and the blade lower surface. The mixed layer on the lower surface of the blade may be provided over the entire range of the free end length of the blade (tip portion without sheet metal on the back of the rubber, depending on the product shape), but is preferably in the range of about 5 mm from the tip ridge line portion. .
Also, the back side (62d side in FIG. 1 (b)) of the lower surface of the blade may not have a mixed layer, but when the mixed layer is formed by dipping, the surface on the 62d side is also impregnated. It may have a layer. When the tip ridge line portion 62c is immersed downward at the time of dipping, no mixed layer is formed on the 62d side, and the effect of the present invention is also exhibited in such a configuration.

Further, the tip ridge portion of the elastic blade is covered with an acrylic / methacrylic resin formed using a material containing a compound having a functional group equivalent molecular weight of 110 or less and a pentaerythritol / triacrylate skeleton having 3 to 6 functional groups as a monomer component. It is preferable that the movement of the tip of the elastic blade is moderately suppressed and the wear resistance can be improved. The compound having a pentaerythritol triacrylate skeleton having a functional group equivalent molecular weight of 110 or less and a functional group number of 3 to 6 is preferably the main component of the monomer component forming the surface layer.
The surface layer is preferably formed so as to have a maximum film thickness of 5 μm. Thereby, while giving sufficient wear resistance to the tip ridge line portion, due to the fact that the surface layer is too hard or too thick, the followability to the image carrier surface of the tip ridge line portion is reduced, It can be prevented that a uniform contact state cannot be obtained and toner slip-through increases to easily cause a cleaning failure or to generate abnormal noise. The film thickness of the surface layer is more preferably 0.5 to 5 μm. Even when the elastic blade contacts the member to be cleaned in a short time when used over time, the surface layer is thinned, and the hardness is higher than the elastic blade in which the elastic blade base material and acrylic / methacrylic resin are mixed. Since the layer portion is in contact with the member to be cleaned, the friction coefficient of the wear surface can be suppressed even after the progress of wear, and the occurrence of stick-slip motion can be suppressed.
As the compound having a functional group equivalent molecular weight of 110 or less and a pentaerythritol / triacrylate skeleton having 3 to 6 functional groups, pentaerythritol / triacrylate (PETIA or PETRA manufactured by Daicel Ornex Co., Ltd., mixing of 3 and 4 functional groups, equivalent molecular weight) 108), dipentaerythritol hexaacrylate (A-9550 manufactured by Shin-Nakamura Chemical Co., Ltd., functional group number 6, equivalent molecular weight 96) and the like.

Further, the acrylic / methacrylic resin of the surface layer preferably contains an acrylic monomer having a perfluoropolyether skeleton and having two or more functional groups as a monomer component. By further including an acrylic monomer having a perfluoropolyether skeleton and a functional group number of 2 or more as the monomer component, the wear resistance can be further improved.
As an acrylate having a perfluoropolyether skeleton and having two or more functional groups, Daikin Corporation: OPTOOL DAC-HP (solid content concentration: 20% by mass), DIC Corporation: Megafuck RS-75 (solid content concentration: 40% by mass) ) And the like.
The acrylic monomer having a perfluoropolyether skeleton and having 2 or more functional groups is preferably contained in an amount of 0.1 to 5% by mass, more preferably, based on the total monomer components of the acrylic / methacrylic resin forming the surface layer. Is about 0.1 to 2% by mass.

FIG. 5 is a perspective view of the cleaning blade 62, and FIG. 1 is an enlarged cross-sectional view of the cleaning blade 62. FIG. 1A is an explanatory diagram showing a state in which the cleaning blade 62 is in contact with the surface of the photosensitive member 3, and FIG. 1B is an enlarged explanatory diagram in the vicinity of the tip ridge line portion 62 c 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 impregnated in the tip ridge portion 62c and has a mixed layer of acrylic / methacrylic resin and urethane resin. Further, a surface layer 623 that is an acrylic / methacrylic resin film is formed in the blade longitudinal direction in the region including the entire blade tip surface 62a and the tip ridge line portion of the blade lower surface 62b.
The elastic blade 622 is fixed to one end side of the holder 621 with an adhesive or the like, and the other end side of the holder 621 is cantilevered by the case of the cleaning device.

In the present invention, the elastic blade 622 is made of urethane rubber having an equilibrium swelling ratio of 200% or more when immersed in cyclohexanone. A material having a high rebound resilience is preferable so that it can follow the eccentricity of the photoreceptor 3 and minute waviness on the surface of the photoreceptor 3, and urethane rubber having a rebound resilience at 75 ° C. of 75% or more is suitable.
Further, the urethane rubber hardness of the elastic blade 622 is preferably urethane rubber having a JIS-A hardness of 67 ° or less as measured with a JIS-A hardness meter or a micro rubber hardness meter MD-1 manufactured by ASKER. Those that do not satisfy this condition, because the crosslinking density of the rubber is too high, as will be described later, even if the surface layer 623 is formed by modification by impregnation treatment, the durability performance is not sufficient, Long-term use greatly increases the wear on the ridgeline, and as a result, the cleaning performance may be reduced.

  Note that the hardness of the elastic blade 622 changes due to the modification of the urethane rubber itself by the impregnation treatment, and is also influenced by the formation of the surface layer 623, so it is necessary to adjust the respective effects.

  The impregnation treatment to the tip ridge line portion 62c of the elastic blade 622 can be performed by impregnating a material containing a monomer that becomes an acrylic / methacrylic resin by brush coating, spray coating, dip coating, or the like. As the acrylic / methacrylic resin forming the mixed layer, it is preferable to use a material containing at least a functional group equivalent molecular weight of 200 or less and an alicyclic acrylate monomer having 2 functional groups. By having the mixed layer, it is possible to prevent the leading edge ridge line portion 62c of the elastic blade 622 in contact with the surface of the photosensitive member 3 from being deformed. Furthermore, even when the interior is exposed due to the surface layer wear over time, the deformation can be similarly suppressed by the impregnation action.

  The surface layer 623 is formed by impregnating the elastic blade 622 with an acrylic / methacrylic resin material and air-drying it for a predetermined time, and then spraying, dip coating, screen printing, or the like on the front edge line portion 62c of the cleaning blade 62. It is formed by coating. As the surface layer 623, a material containing a compound having a functional group equivalent molecular weight of 350 or less and having a pentaerythritol triacrylate skeleton having 3 to 6 functional groups as a monomer component, the blade tip surface is the entire surface, and the blade bottom surface is the tip ridge line portion. It is preferable to adjust and form the film thickness within a range of 2 mm or more. Due to the effect of the rigid surface layer 623, the elastic blade 622 is not easily deformed, and the leading edge portion 62c of the cleaning blade 62 is prevented from being pulled in, and stick-slip motion can be suppressed.

After impregnating a material containing a monomer that becomes an acrylic / methacrylic resin, or after coating with the surface layer 623, the mixed layer of acrylic / methacrylic resin and urethane rubber shown in FIG. 1 is irradiated with ultraviolet rays. The portion 62d can be formed, and a modification effect for increasing the hardness of the tip ridge line portion 62c can be produced. In the elastic blade described in Japanese Patent Application Laid-Open No. 2010-152295, modification is performed by impregnation with an isocyanate compound, a fluorine compound, a silicone compound, etc., but a monomer that becomes an acrylic / methacrylic resin as in this embodiment is used. Durability can be further improved by impregnating the containing material and irradiating with ultraviolet rays. This is thought to be due to the following reasons. First of all, it is possible that the crosslink density of the rubber itself is artificially increased and the wear resistance is improved by the formation of an acrylic / methacrylic resin network chain inside the rubber. In this case, the point is that the acrylic / methacrylic resin and urethane rubber will hardly be chemically bonded. Generally, when trying to reinforce urethane rubber by impregnation operation, isocyanate is often used as the impregnation material, but since isocyanate reacts chemically with urethane rubber, the crosslinking density increases too much, and glass rather than rubber is used. Therefore, it is conceivable that the movement of the edge is excessively suppressed and the wear resistance is deteriorated.
Another possibility is that the acrylic / methacrylic resin in the mixed layer exerts a so-called “anchor effect” on the acrylic / methacrylic resin added to the surface to increase the adhesion between the resin film and the rubber. It is possible that Accordingly, it can be considered that the durability of the acrylic / methacrylic resin film itself is increased.

  As described above, urethane rubber having a rebound elastic modulus of 75% or more at 23 ° C. and a JIS-A hardness of 67 ° or less is preferable as the base material of the elastic blade 622. Those that do not satisfy this condition are too high in the inherent crosslinking density of the rubber, making it difficult for the acrylic resin to be impregnated, making it difficult to obtain a sufficient modification effect, that is, a durability improvement effect. It is possible to impregnate a large amount of acrylic / methacrylic resin by soaking for a long time, but since the diluting solvent is also soaked at the same time, the rubber swells and the tip ridge line cannot maintain 90 °, and the straightness of the ridge line As a result, the cleaning performance may deteriorate. On the other hand, a urethane rubber having a low crosslinking density that satisfies the above conditions can be impregnated with an acrylic / methacrylic resin for a relatively short period of time or with only a small amount of a diluting solvent. Cleaning performance can be improved by improving wear resistance and suppressing large deformation of the elastic blade.

  The elastic blade 622 is preferably modified using a material containing at least a functional group equivalent molecular weight of 200 or less and an alicyclic acrylate monomer having two functional groups as the acrylic / methacrylic resin forming the mixed layer. When a material having a small functional group equivalent molecular weight and a large number of functional groups of 3 or more is used, the crosslink density is increased too much, and it becomes a state closer to glass rather than rubber. In some cases, wear resistance may be deteriorated. On the other hand, if the functional group equivalent is too large, a sufficient effect of improving the wear resistance may not be obtained.

  Further, the surface layer 623 is provided so as to have an inclination so as to gradually become thinner from the leading edge portion, so that the leading edge portion can follow the photoreceptor 3 due to the hard or thick surface layer 623 being formed. It is possible to suppress the decrease and improve the cleaning performance compared with the original elastic blade. Thus, even if the surface layer 623 is thinned and the elastic blade 622 contacts the photoconductor 3 in a short time in use over time, the elastic blade 622 is more than the elastic blade 622 in which the base material of the elastic blade 622 and the acrylic / methacrylic resin are mixed. Since the mixed layer portion having high hardness comes into contact with the photoreceptor 3, the occurrence of abnormal wear and abnormal noise during use over time can be suppressed.

The cleaning blade 62 of the present invention is an acrylic / methacrylic resin that forms a surface layer 623 by impregnating a base material of an elastic blade 622 made of, for example, urethane rubber with a material that becomes an acrylic / methacrylic resin by dip coating. After spraying the material, it can be obtained by curing the resin by ultraviolet irradiation.
As the timing of irradiating the ultraviolet ray to cure the impregnated acrylic / methacrylic resin material, after the elastic blade 622 is impregnated with the acrylic / methacrylic resin material, before the surface layer 623 is formed, the ultraviolet ray is irradiated. May be irradiated. A surface layer 623 is formed after impregnating a material to be an acrylic / methacrylic resin into urethane rubber which is a base material of the elastic blade 622, and once curing the material to be an acrylic / methacrylic resin impregnated by irradiation with ultraviolet rays. If it is the structure coat | covered with the resin to which it becomes, the material used as the acrylic / methacrylic resin which fixes the state of the mixed layer of urethane rubber and an acrylic / methacrylic resin before forming the surface layer 623, and forms the surface layer 623 later Even if it is applied, the state of the mixed layer does not change, so that the elastic blade 622 having a desired mixed layer can be manufactured.

As shown by the arrow in FIG. 1B, the cleaning blade 62 of the present invention is inclined such that the inside of the elastic blade 622 in the mixed layer portion 62d has a smaller acrylic / methacrylic resin content with respect to urethane rubber. It is preferable to impregnate so that property may arise.
Specifically, by performing the impregnation operation for a short time or under difficult conditions, the amount of the material to be impregnated acrylic / methacrylic resin is reduced, and the outside of the elastic blade 622 in the impregnated portion is The impregnation operation is performed so that the amount of impregnation is large and the amount of impregnation decreases toward the inside. In the present embodiment, cyclohexanone having a low penetration rate into rubber is used as a dilution solvent for the material to be an acrylic / methacrylic resin, and the impregnation operation is performed by a dipping method, and the impregnation time is 120 [seconds].

A mixed layer of elastic blades 622 inside the surface layer 623 with high hardness exists so that the acrylic / methacrylic resin has a gradient with respect to the base material. Strength and rigidity are moderately strengthened. As a result, good cleaning can be performed by moderately suppressing the behavior of the blade tip during sliding with the surface of the photosensitive member 3, and high wear resistance can be achieved by suppressing abnormal wear and abnormal noise. It becomes possible to make it.
Further, if only the surface layer 623 having a high hardness is provided on the base material of the elastic blade 622, the hardness changes suddenly at the boundary between the high hardness layer and the base material layer, stress concentrates, and the elastic blade 622 may be damaged. There is. In contrast, by causing the mixed layer of the base material of the elastic blade 622 to have a gradient in the acrylic / methacrylic resin content, the hardness changes rapidly at the boundary between the high hardness layer and the base material layer. It is possible to suppress the elastic blade 622 from being damaged due to stress concentration.

In the cleaning blade 62 of the present invention, a surface layer 623 that is harder than the base material is provided to reduce the coefficient of friction between the tip ridge line portion 62 c and the surface of the photoreceptor 3.
Even if a mixed layer of acrylic / methacrylic resin is not formed on the base material of the elastic blade 622 and only the surface layer 623 having a hardness higher than that of the base material is provided to reduce the friction coefficient, the surface layer 623 is worn over time. Then decrease. At this time, if the surface layer 623 is made thick so that it can withstand long-term use, there is a risk that the elastic deformation at the tip ridge line portion 62c of the elastic blade 622 is inhibited, resulting in poor cleaning. On the other hand, if the surface layer 623 is made thin so as not to hinder elastic deformation at the tip ridge line portion 62c of the elastic blade 622, the surface layer 623 is worn to such an extent that the base material is exposed in a short time. When the low-hardness base material is exposed and directly contacts the surface of the photoconductor 3, the friction coefficient between the cleaning blade 62 and the surface of the photoconductor 3 increases, and abnormal wear and noise occur.
Also, if the structure is only impregnated with a resin material, the hardness of the portion that comes into contact with the photosensitive member of the cleaning blade at the beginning of use cannot be as high as that provided with a surface layer, and wear resistance is reduced. It becomes insufficient.

  As described above, in the present invention, since the hardness is increased by providing the mixed layer in a portion including the tip ridge line portion 62c of the elastic blade 622, the tip ridge line portion 62c of the elastic blade 622 is hardly deformed. Yes.

  In the present invention, the surface layer 623 is formed on the entire surface of the blade tip surface 62a and on the lower surface of the blade including the tip ridge line portion 62c, preferably in a range of 2 mm or more from the tip ridge line portion 62c. This prevents the elastic deformation of the elastic blade 622 at the tip ridge line portion 62c from being inhibited and prevents the tip ridge line portion 62c from turning over, compared to the case where the surface layer 623 is formed only on the blade tip surface 62a. The tip ridge line portion 62c of the blade 622 can be elastically deformed in the moving direction of the surface of the photoreceptor 3. As a result, even when the photosensitive member 3 is eccentric, the leading edge portion 62c can follow the surface of the photosensitive member 3 by the restoring force against the elastic deformation of the leading edge portion 62c of the elastic blade 622. Good cleaning properties can be maintained.

  Further, by using an acrylic / methacrylic resin as the material of the surface layer 623, the surface layer 623 having a desired hardness can be obtained simply by irradiating the resin adhering to the tip ridge line portion 62c of the cleaning blade 62 with ultraviolet rays. The cleaning blade 62 can be manufactured at a low cost.

  As the acrylic / methacrylic resin for the surface layer, it is preferable to use, as a monomer component, a compound having a pentaerythritol triacrylate skeleton having a functional group equivalent molecular weight of 110 or less and having 3 to 6 functional groups. When the functional group equivalent molecular weight exceeds 110 or a material other than the pentaerythritol triacrylate skeleton is used, the surface layer 623 becomes brittle, and the tip ridge line portion 62c of the cleaning blade 62 is turned over as shown in FIG. 7B. End surface wear may occur, and long-term cleaning properties may not be maintained.

As a material for the surface layer 623, an acrylate material having 1 to 2 functional groups can be appropriately mixed in addition to the pentaerythritol / triacrylate skeleton material. Thus, flexibility can be imparted to the surface layer 623, and the properties of the surface layer 623 can be customized in accordance with the characteristics of the machine on which the cleaning blade 62 is mounted.
Therefore, it is possible to improve environmental characteristics and the like, for example, by finely adjusting the blade behavior when abnormal noise occurs in a specific environment.
Examples of the acrylate material having 1 to 2 functional groups include the following.
Monofunctional: isobornyl acrylate, octyl / decyl acrylate, ethoxylated phenyl acrylate, lauryl acrylate, stearyl acrylate, methoxytriethylene glycol acrylate, methoxytripropylene glycol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, ethoxylated o- Phenylphenol acrylate, dicyclopentanyl acrylate, tetrahydrofurfuryl acrylate, etc. Bifunctional: 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, polyethylene polypropylene glycol diacrylate Acrylate, tripropylene glycol diacrylate, PO-modified neopentyl glycol diacrylate, modified Bisphenol A diacrylate, neopentyl glycol / hydroxypivalate ester diacrylate, dioxane glycol diacrylate, 9,9-bis [4- (2-hydroxyethoxy) phenyl] full orange acrylate, other / urethane acrylates from various manufacturers, Such.

  Further, the film thickness of the surface layer 623 is preferably 5 μm or less. If it exceeds this, the rigidity of the tip ridge line portion 62c of the cleaning blade 62 becomes too strong, and the behavior in sliding with the surface of the photoreceptor 3 may become too small. As a result, the vibration energy concentrates on the tip ridge portion 62c, so that unpleasant noise is likely to occur, and the wear rate increases, and the cleaning function may be deteriorated at an early stage and become unusable. is there. On the other hand, if it is too soft, the deformation of the tip ridge line portion 62c becomes excessively large and wears out early, and the toner that slips through is crushed.

You may use a photoinitiator for the solution used for formation of the said mixed layer and surface layer.
The photopolymerization initiator is not particularly limited as long as it generates active species such as radicals and cations by the energy of light and initiates polymerization, and can be appropriately selected according to the purpose. A polymerization initiator, a photocationic polymerization initiator, etc. are mentioned.
Among these, a photo radical polymerization initiator is particularly preferable.

  Examples of the radical photopolymerization initiator include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazoles, and the like. Examples thereof include compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

There is no restriction | limiting in particular as said radical photopolymerization initiator, According to the objective, it can select suitably.
For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4 -Chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methyl Propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropyl Oxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2 , 4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, and the like. These may be used individually by 1 type and may use 2 or more types together.

Commercially available products can be used as the photoradical polymerization initiator. Examples of the commercially available products include Irgacure 651, Irgacure 184, DAROCUR 1173, Irgacure 2959, Irgacure 127, Irgacure 907, Irgacure 369, Irgacure 379, and DAROCUR. TPO, IRGACURE 819, IRGACURE 784, IRGACURE OXE 01, IRGACURE OXE 02, IRGACURE 754 (above, manufactured by Ciba Specialty Chemicals); Speedcure TPO (manufactured by Lambson); KAYACURE DETX-S Co., Ltd. Lucirin TPO, LR8883, LR8970 (above, manufactured by BASF); Ubekrill P36 (manufactured by UCB), and the like. These may be used individually by 1 type and may use 2 or more types together.
The content of the photopolymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1% by mass to 20% by mass with respect to the ultraviolet curable composition.

  An image forming apparatus according to the present invention is an image forming apparatus that finally transfers an image formed on an image carrier, which is a surface moving member, to a recording medium, and contacts the surface of the image carrier and adheres to the surface. The cleaning blade of the present invention is provided as a cleaning member for removing unnecessary deposits. The image carrier may be provided with a mechanism for applying a lubricant as a cleaning auxiliary means.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment (hereinafter referred to as an embodiment) of an electrophotographic printer (hereinafter simply referred to as a printer 500) will be described. First, a basic configuration of the printer 500 according to the present embodiment will be described.
FIG. 2 is a schematic configuration diagram illustrating the printer 500. The printer 500 includes four image forming units 1Y, C, M, and K for yellow, magenta, cyan, and black (hereinafter referred to as Y, C, M, and K). These use Y, C, M, and K toners of different colors as image forming substances for forming an image, but the other configurations are the same.

Above the four image forming units 1, a transfer unit 60 including an intermediate transfer belt 14 as an intermediate transfer member is disposed. The toner images of the respective colors formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K included in the image forming units 1Y, 1C, 1M, and 1K, which will be described in detail later, are superimposed on the surface of the intermediate transfer belt 14. It is a configuration to be transferred.
Further, an optical writing unit 40 is disposed below the four image forming units 1. The optical writing unit 40 serving as a latent image forming unit irradiates the photoconductors 3Y, C, M, and K of the image forming units 1Y, 1C, 1M, and 1K with a laser beam L emitted based on the image information. Thereby, electrostatic latent images for Y, C, M, and K are formed on the photoreceptors 3Y, 3C, 3M, and 3K. The optical writing unit 40 deflects the laser light L emitted from the light source by the polygon mirror 41 that is rotationally driven by a motor, and passes through the photoreceptors 3Y, 3C, 3M, and 3K via a plurality of optical lenses and mirrors. Is irradiated. In place of such a configuration, an optical scanning device using an LDE array may be employed.

  Below the optical writing unit 40, a first paper feed cassette 151 and a second paper feed cassette 152 are arranged to overlap in the vertical direction. In each of these paper feed cassettes, a plurality of transfer papers P as recording media are accommodated in a stack of paper sheets. The uppermost transfer paper P includes a first paper feed roller 151a, The second paper feed rollers 152a are in contact with each other. When the first paper feed roller 151a is driven to rotate counterclockwise in the figure by the driving means, the uppermost transfer paper P in the first paper feed cassette 151 extends vertically on the right side of the cassette in the figure. The paper is discharged toward the paper feed path 153 arranged to exist. When the second paper feed roller 152a is driven to rotate counterclockwise in FIG. 2 by the driving means, the uppermost transfer paper P in the second paper feed cassette 152 is discharged toward the paper feed path 153. Is done.

  A plurality of conveying roller pairs 154 are arranged in the paper feed path 153. The transfer paper P sent to the paper feed path 153 is conveyed from the lower side to the upper side in FIG. 2 while being sandwiched between the rollers of the conveyance roller pair 154.

  A registration roller pair 55 is disposed at the downstream end of the paper feed path 153 in the transport direction. The registration roller pair 55 temporarily stops the rotation of both rollers as soon as the transfer paper P sent from the conveyance roller pair 154 is sandwiched between the rollers. Then, the transfer paper P is sent out toward a secondary transfer nip described later at an appropriate timing.

FIG. 3 is a configuration diagram showing a schematic configuration of one of the four image forming units 1.
As shown in FIG. 3, the image forming unit 1 includes a drum-shaped photoconductor 3 as an image carrier. The photosensitive member 3 has a drum shape, but may be a sheet shape or an endless belt shape.
Around the photoreceptor 3, a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a lubricant application device 10, a static elimination lamp, and the like are disposed. The charging roller 4 is a charging member provided in a charging device as a charging unit, and the developing device 5 is a developing unit that converts a latent image formed on the surface of the photoreceptor 3 into a toner image. The primary transfer roller 7 is a primary transfer member provided in a primary transfer device as a primary transfer unit that transfers a toner image on the surface of the photoreceptor 3 to the intermediate transfer belt 14. The cleaning device 6 is a cleaning unit that cleans the toner remaining on the photoreceptor 3 after the toner image is transferred to the intermediate transfer belt 14. The lubricant application device 10 is a lubricant application unit that applies a lubricant onto the surface of the photoreceptor 3 after the cleaning device 6 performs cleaning. The neutralization lamp is a neutralization unit that neutralizes the surface potential of the photoreceptor 3 after cleaning.

  The charging roller 4 is arranged 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 surface of the photoreceptor 3 uniformly charged by the charging roller 4 is irradiated with laser light L from an optical writing unit 40 serving as a latent image forming unit based on image information, thereby forming 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. 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. The developer is pumped up on the surface of the developing roller 51, and the developer pumped up is regulated by the doctor 54, and the toner adheres to the latent image on the photoconductor 3 in the development area facing the photoconductor 3. .

  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 cleaning blade 62 is the cleaning blade of the present invention. The lubricant application device 10 includes a solid lubricant 103, a lubricant pressure spring 103 a, and the like, and uses a fur brush 101 as an application brush for applying the solid lubricant 103 onto the photoreceptor 3. The solid lubricant 103 is held by the bracket 103b and is pressed toward the fur brush 101 by a lubricant pressurizing spring 103a. Then, the solid lubricant 103 is scraped 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. It is preferable that the coefficient of friction of the surface of the photoconductor 3 is maintained at 0.2 or less during non-image formation by applying a lubricant to the photoconductor.

  The charging device according to the present embodiment is a non-contact proximity arrangement system in which the charging roller 4 is brought close to the photosensitive member 3, and examples of the charging device include corotron, scorotron, and solid state charger (solid state charger). A known configuration can be 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.

The light source of the laser light L of the optical writing unit 40 and the light source such as a static elimination lamp include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). ) And other luminescent materials 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, light emitting diodes and semiconductor lasers are used favorably because they have high irradiation energy and have long wavelength light of 600 to 800 [nm].

  In addition to the intermediate transfer belt 14, the transfer unit 60 serving as transfer means includes a belt cleaning unit 162, a first bracket 63, a second bracket 64, and the like. Also provided are four primary transfer rollers 7Y, 7C, 7M, 7K, secondary transfer backup roller 66, drive roller 67, auxiliary roller 68, tension roller 69, and the like. The intermediate transfer belt 14 is endlessly moved in the counterclockwise direction in the drawing by the rotational driving of the driving roller 67 while being stretched around these eight roller members. The four primary transfer rollers 7Y, 7C, 7M, and 7K each have an intermediate transfer belt 14 that is endlessly moved in this manner, and forms a primary transfer nip between the photoreceptors 3Y, 3C, 3M, and 3K. . Then, a transfer bias having a polarity opposite to that of the toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 14. The intermediate transfer belt 14 sequentially passes through the primary transfer nips for Y, C, M, and K along with the endless movement thereof, and on the surface of the photoreceptor 3Y, C, M, K on the front surface. Y, C, M, and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 14.

  The secondary transfer backup roller 66 sandwiches the intermediate transfer belt 14 with the secondary transfer roller 70 disposed outside the loop of the intermediate transfer belt 14 to form a secondary transfer nip. The registration roller pair 55 described above feeds the transfer paper P sandwiched between the rollers toward the secondary transfer nip at a timing at which the transfer paper P can be synchronized with the four-color toner image on the intermediate transfer belt 14. The four-color toner image on the intermediate transfer belt 14 is affected by the secondary transfer electric field formed between the secondary transfer roller 70 to which the secondary transfer bias is applied and the secondary transfer backup roller 66, and the influence of the nip pressure. The secondary transfer is performed on the transfer paper P in the secondary transfer nip. Then, combined with the white color of the transfer paper P, a full color toner image is obtained.

  Transfer residual toner that has not been transferred to the transfer paper P adheres to the intermediate transfer belt 14 after passing through the secondary transfer nip. This is cleaned by the belt cleaning unit 162. The belt cleaning unit 162 has a belt cleaning blade 162a in contact with the front surface of the intermediate transfer belt 14, thereby scraping off and removing the transfer residual toner on the intermediate transfer belt 14.

  The first bracket 63 of the transfer unit 60 swings at a predetermined rotation angle about the rotation axis of the auxiliary roller 68 as the solenoid is turned on / off. When forming a monochrome image, the printer 500 rotates the first bracket 63 a little counterclockwise in the drawing by driving the solenoid described above. By this rotation, the primary transfer rollers 7Y, C, and M for Y, C, and M are revolved counterclockwise in the drawing around the rotation axis of the auxiliary roller 68, so that the intermediate transfer belt 14 is rotated in the Y, C, and Y directions. It is separated from the photoconductors 3Y, 3C, 3M for M. Of the four image forming units 1Y, 1C, 1M, and 1K, only the K image forming unit 1K is driven to form a monochrome image. Accordingly, it is possible to avoid wear of each member constituting the image forming unit 1 due to wasteful driving of the Y, C, M image forming unit 1 during monochrome image formation.

  A fixing unit 80 is disposed above the secondary transfer nip in the drawing. The fixing unit 80 includes a pressure heating roller 81 that contains a heat source such as a halogen lamp, and a fixing belt unit 82. The fixing belt unit 82 includes a fixing belt 84 as a fixing member, a heating roller 83 containing a heat source such as a halogen lamp, a tension roller 85, a driving roller 86, a temperature sensor, and the like. Then, the endless fixing belt 84 is endlessly moved in the counterclockwise direction in the drawing while being stretched by the heating roller 83, the tension roller 85, and the driving roller 86. In the process of endless movement, the fixing belt 84 is heated from the back side by the heating roller 83. A pressure heating roller 81 that is driven to rotate in the clockwise direction in the drawing is in contact with the surface of the fixing belt 84 that is heated in this manner, around the heating roller 83. Thus, a fixing nip where the pressure heating roller 81 and the fixing belt 84 abut is formed.

  A temperature sensor is disposed outside the loop of the fixing belt 84 so as to face the front surface of the fixing belt 84 with a predetermined gap, and the surface temperature of the fixing belt 84 immediately before entering the fixing nip. Is detected. This detection result is sent to the fixing power supply circuit. The fixing power supply circuit performs on / off control of power supply to the heat generation source included in the heating roller 83 and the heat generation source included in the pressure heating roller 81 based on the detection result of the temperature sensor.

  The transfer paper P that has passed through the secondary transfer nip described above is separated from the intermediate transfer belt 14 and then sent into the fixing unit 80. Then, in the process of being conveyed from the lower side to the upper side in the figure while being sandwiched between the fixing nips in the fixing unit 80, the full-color toner image is fixed on the transfer paper P by being heated and pressed by the fixing belt 84. The

  The transfer paper P subjected to the fixing process in this manner is discharged between the discharge roller pair 87 and then discharged outside the apparatus. A stack unit 88 is formed on the upper surface of the housing of the printer 500 main body, and the transfer paper P discharged to the outside by the discharge roller pair 87 is sequentially stacked on the stack unit 88.

  Above the transfer unit 60, four toner cartridges 100Y, 100C, M, and K that store Y, C, M, and K toners are disposed. The Y, C, M, and K toners in the toner cartridges 100Y, 100C, M, and K are appropriately supplied to the developing devices 5Y, 5C, 5M, and 5K of the image forming units 1Y, 1C, 1M, and 1K. The toner cartridges 100Y, 100C, 100M, and 100K are detachable from the printer main body independently of the image forming units 1Y, 1C, 1M, and 1K.

Next, an image forming operation in the printer 500 will be described.
When a print execution signal is received from the operation unit or the like, a predetermined voltage or current is sequentially applied to the charging roller 4 and the developing roller 51 at a predetermined timing. Similarly, a predetermined voltage or current is sequentially applied to the optical writing unit 40 and a light source such as a static elimination lamp at a predetermined timing. In synchronism with this, the photosensitive member 3 is rotationally driven in the direction of the arrow in the figure by a photosensitive member driving motor as driving means.

When the photoconductor 3 rotates in the direction of the arrow in the figure, the surface of the photoconductor 3 is first uniformly charged to a predetermined potential by the charging roller 4. Then, the laser beam L corresponding to the image information is irradiated onto the photoconductor 3 from the optical writing unit 40, and the portion irradiated with the laser light L on the surface of the photoconductor 3 is neutralized to form an electrostatic latent image. .
The surface of the photoreceptor 3 on which the electrostatic latent image is formed is rubbed by a developer magnetic brush formed on the developing roller 51 at a portion facing the developing device 5. 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 to be converted into a toner image (development). In each image forming unit 1, a similar image forming process is executed, and a toner image of each color is formed on the surface of each photoreceptor 3Y, C, M, K of each image forming unit 1Y, C, M, K. .
As described above, in the printer 500, the electrostatic latent image formed on the photoconductor 3 is reversely developed by the developing device 5 with the negatively charged toner. 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 images of the respective colors formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K are sequentially primary-transferred so as to overlap on the surface of the intermediate transfer belt 14. As a result, a four-color toner image is formed on the intermediate transfer belt 14.
The four-color toner image formed on the intermediate transfer belt 14 is fed from the first paper feed cassette 151 or the second paper feed cassette 152, passed between the rollers of the registration roller pair 55, and fed to the secondary transfer nip. The transfer paper P is transferred. At this time, the transfer paper P is temporarily stopped while being sandwiched between the registration roller pair 55, and is supplied to the secondary transfer nip in synchronization with the leading edge of the image on the intermediate transfer belt 14. The transfer paper P onto which the toner image has been transferred is separated from the intermediate transfer belt 14 and conveyed to the fixing unit 80. Then, the transfer paper P on which the toner image is transferred passes through the fixing unit 80, whereby the toner image is fixed on the transfer paper P by the action of heat and pressure, and the transfer paper P on which the toner image is fixed is the printer. 500 is discharged outside the apparatus and stacked on the stack unit 88.

On the other hand, the transfer residual toner on the surface of the intermediate transfer belt 14 that has transferred the toner image onto the transfer paper P at the secondary transfer nip is removed by the belt cleaning unit 162.
Further, the surface of the photoreceptor 3 on which the toner images of the respective colors are transferred to the intermediate transfer belt 14 at the primary transfer nip, the residual toner after the transfer is removed by the cleaning device 6, and the lubricant is applied by the lubricant applying device 10. Thereafter, the charge is removed by a charge removal lamp.

  As shown in FIG. 3, the image forming unit 1 of the printer 500 includes a photosensitive member 3 and a charging roller 4, a developing device 5, a cleaning device 6, a lubricant applying device 10, and the like as process means. Yes. The image forming unit 1 can be integrally attached to and detached from the main body of the printer 500 as a process cartridge. In the printer 500, the image forming unit 1 integrally replaces the photosensitive member 3 as a process cartridge and the process means, but the photosensitive member 3, the charging roller 4, the developing device 5, the cleaning device 6, the lubrication device. The composition may be replaced with a new one in the unit such as the agent coating apparatus 10.

Next, toner suitable for the printer 500 to which the present invention is applied will be described.
As the toner used in the printer 500, 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 (trade name, manufactured by Toa Medical Electronics Co., Ltd.). Specifically, a surfactant, preferably an alkylbenzene sulfonate, is added in an amount of 0.1 to 0.5 [ml] as a dispersant in 100 to 150 [ml] of water from which impure solids have been removed in advance. 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 this measurement result, the outer peripheral length of the actual toner projection shape shown in FIG. 4A 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 dispersion treatment is performed for about 1 to 3 [minutes] with 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.

In such a polymerized toner, even if an attempt is made to remove the pulverized toner with the cleaning blade 62 in the same manner as when the conventional pulverized toner is removed from the surface of the photoreceptor 3, the polymerized toner cannot be sufficiently removed from the surface of the photoreceptor 3. A cleaning failure occurs. Further, low-temperature fixing toner using a crystalline resin in recent years is greatly deformed when passing through the blade, and is fixed to the edge of the blade or fused to the surface of the photoreceptor. Therefore, when the contact pressure of the cleaning blade 62 to the photosensitive member 3 is increased to improve the cleaning performance, there is a problem that the cleaning blade 62 wears out early. In addition, the frictional force between the cleaning blade 62 and the photosensitive member 3 is increased, and the leading edge portion of the cleaning blade 62 in contact with the photosensitive member 3 is pulled in the moving direction of the photosensitive member 3 so that the leading edge portion is turned. End up. When the tip ridge line portion of the cleaning blade 62 is turned, various problems such as abnormal noise, vibration, and lack of the tip ridge line portion occur.
The cleaning blade of the present invention does not cause poor cleaning even with the above-described polymerized toner, and does not cause abnormal noise, vibration, or lack of a tip ridge line portion.

  The process cartridge of the present invention is configured to be detachable from a main body of an image forming apparatus that finally transfers an image formed on a surface-moving latent image carrier to a recording medium, and the latent image carrier is attached to the member to be cleaned. In the process cartridge that integrally supports the cleaning means having a cleaning member that contacts the surface and removes unnecessary deposits attached on the surface, and the latent image carrier, the cleaning member is the present invention. This is a cleaning blade. A mechanism for applying a lubricant to the surface of the latent image carrier may be provided as a cleaning auxiliary means.

  Next, examples performed by the applicants will be described. In addition, "part" used in an Example represents a "mass part".

(Example 1 to Example 11, Comparative Example 1 to Comparative Example 7)
The durability test was conducted by changing the material of the elastic blade, the material of the surface layer, the impregnation method, and the formation of the surface layer on the lower surface of the blade.
As the urethane rubber of the elastic blade, four urethane rubbers having JIS-A hardness in Table 1, 23 ° C. rebound resilience, and equilibrium swelling ratio when immersed in cyclohexanone were prepared.

The rebound resilience of urethane rubber is No. manufactured by Toyo Seiki Seisakusho. The measurement was performed according to JIS K6255 using a 221 regilynester. The sample was a stack of about 2 [mm] sheets so that the thickness was 4 [mm] or more.
Moreover, the equilibrium swelling rate measurement result using cyclohexanone is also described. This was measured in accordance with JISK6258 as the rate of mass change after 48 hours immersion under the following conditions.
・ Size of the test piece: 2 mm square is cut off from the blade with a cutter etc. ・ 48 hours standing temperature: 23 ° C. (The humidity is not specified because it is in a sealed container)
・ Removal of excess liquid: sandwich test piece with Kim Towel White (Nippon Paper Crecia)

As materials used for the impregnation treatment and the surface layer formation treatment, those having resin material formulations 1 to 8 shown in Table 2 were used.
Details of the monomers in Table 2 are shown in Table 3.

Next, the configuration of the evaluated image forming apparatus will be described.
A strip-shaped elastic blade substrate having a thickness of 1.8 [mm] is produced using any of the urethane rubbers 1 to 4, and the resin material is formed by using about 2 mm of the tip of the substrate as an impregnation material. Using any one of Formulations 6 to 8, after soaking for the time shown in Table 3, air-dry for 3 minutes. Furthermore, the surface layer which consists of one of the said resin material prescriptions 1-5 was formed with the spray coating method. Specifically, for each elastic blade made of urethane rubber appropriately impregnated, the layers described in Table 3 were first spray-coated at a spray gun moving speed of 10 [mm / s] from the blade tip surface. Overcoating was applied to the entire tip surface so as to be thick. After touch-drying for 3 minutes, coating was performed on the lower surface of the blade so that a surface layer was formed in a width of about 3 [mm] from the edge of the blade in the same manner as the front surface of the blade. Thereafter, finger touch drying was further performed for 3 minutes, and ultraviolet exposure (140 [W / cm] × 5 [m / min] × 5 passes) was performed.

  The elastic blade on which the surface layer was formed was fixed to a sheet metal holder that can be mounted on the Ricoh color composite machine imagio MP C4500 with an adhesive to form a cleaning blade. This is also mounted on a Ricoh color multifunction printer, imagio MP C4500 (the printer unit has the same configuration as the printer 500 shown in FIG. 2), and image forming apparatuses of Examples 1 to 11 and Comparative Examples 1 to 7 are manufactured. did. The cleaning blade was attached so that the linear pressure was 20 [g / cm] and the cleaning angle was 79 [°]. Further, the apparatus is provided with a lubricant application device on the surface of the photosensitive member, and the coefficient of static friction on the surface of the photosensitive member is maintained at 0.2 or less during non-image formation by applying the lubricant. The method for measuring the coefficient of static friction on the surface of the photoreceptor is the Euler belt method, which is described in paragraph No. 0046 of JP-A-9-166919, for example.

For the evaluation, a low-temperature fixing toner produced 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: 1.5 parts of small particle size silica (Clariant H2000)
0.5 parts small particle size titanium oxide (Taika MT-150AI)
1.0 parts of large particle size silica (UFP-30H manufactured by Denki Kagaku Kogyo)
Glass transition point: 50 ° C
The evaluation was performed in a laboratory environment: 10 [° C.] · 15 [% RH], paper feeding condition: image area ratio 5% chart at 3 prints / job at 100,000 sheets (A4 landscape). And the following items were evaluated.

〔Evaluation item〕
<Maximum thickness of surface layer>
The obtained cleaning blade was cut with a trimming razor or the like, the cross section was observed with VHX-100 manufactured by KEYENCE, and the portion with the thickest surface layer was measured.
<Insufficient cleaning>
As an evaluation image, a vertical band pattern (with respect to the paper traveling direction) 43 [mm] width, 20 pieces of 3 charts in an A4 size are output, and the obtained images are visually observed to check for abnormal images due to poor cleaning. The cleaning property was evaluated based on the presence or absence.
<Wear cross-sectional area>
The abrasion cross-sectional area after passing 100,000 sheets of the cleaning blade was measured with a laser microscope VK-9500 manufactured by KYENCE.
The shape profile measurement of the blade edge line part before and behind use was performed in VK-9500, and the difference was made into the wear cross-sectional area (refer FIG. 8).
<Generation of abnormal noise>
When the blade is not used and after running 100,000 sheets, the high temperature is 32 [° C] / 85 [% RH] and the low temperature is 10 [° C] / 15 [% RH]. An abnormal noise was confirmed.

  The structures of the cleaning blades of the examples and comparative examples and the results of evaluation are shown below.

Table 4 summarizes the results of Examples and Comparative Examples.

Moreover, the conceptual diagram which compares an Example and a comparative example is shown in FIG.
In all of Examples 1 to 11, good cleaning properties could be maintained over time, and the generation of abnormal noise could be suppressed.
In Examples 1 to 11, the hardness is increased by the impregnation treatment, the movement of the tip ridge line portion is not excessively suppressed, and the posture of the tip ridge line portion is maintained at an appropriate level as the cleaning blade. A reforming process has been performed. For this reason, it is considered that generation of abnormal noise over time could be avoided in the configuration in which the surface layer was provided on the blade tip surface. Further, it is considered that the frictional force generated between the photosensitive member and the tip ridge line portion can be reduced, the turning of the tip ridge line portion can be suppressed, and the abrasion of the elastic blade can be suppressed. The surface layer has an effect to reinforce the elastic part near the contact part with the photoconductor, thereby controlling the movement of the edge of the tip appropriately, and without causing abnormal noise, stick slip It is thought that exercise was also suppressed.

  In Examples 1 to 11, the surface layer is made of acrylic / methacrylic resin, so that the surface layer having a desired hardness can be obtained simply by irradiating the resin adhered to the tip ridge line portion of the cleaning blade with ultraviolet rays. The cleaning blade can be manufactured at low cost.

  As described above, in the present exemplary embodiment, the configuration in which the cleaning blade of the present invention is applied to a cleaning device in which a member to be cleaned is a photoconductor is described. However, the member to be cleaned is not limited to a photoconductor. For example, the cleaning blade of the present invention can also be applied as a belt cleaning blade of a belt cleaning unit whose member to be cleaned is an intermediate transfer belt.

DESCRIPTION OF SYMBOLS 1 Image forming unit 2 Frame 3 Photoreceptor 4 Charging roller 5 Developing device 6 Cleaning device 7 Primary transfer roller 10 Lubricant coating device 14 Intermediate transfer belt 40 Optical writing unit 41 Polygon mirror 51 Developing roller 52 Supply screw 53 Conveying screw 54 Doctor 55 Registration roller pair 60 Transfer unit 62 Cleaning blade 62a Blade tip surface 62b Blade bottom surface 62c Tip ridge 62d Mixed layer portion of acrylic / methacrylic resin and urethane rubber 63 First bracket 64 Second bracket 66 Secondary transfer backup roller 67 Driving roller 68 Auxiliary roller 69 Tension roller 70 Secondary transfer roller 80 Fixing unit 81 Pressure heating roller 82 Fixing belt unit 83 Heating roller 84 Fixing belt 85 Tension roller 86 Drive roller 87 Discharge roller pair 88 Stack unit 100 Toner cartridge 101 Fur brush 103 Solid lubricant 103a Lubricant pressure spring 103b Bracket 151 First paper feed cassette 151a First paper feed roller 152 Second paper feed cassette 152a Second Feed roller 153 Feed path 154 Conveying roller pair 162 Belt cleaning unit 162a Belt cleaning blade 500 Printer 621 Holder 622 Elastic blade 623 Surface layer P Transfer paper
L Laser light

JP 2012-083729 A

Claims (9)

A cleaning blade that has an elastic blade and removes residue adhered to the surface of the member to be cleaned from the surface of the member to be cleaned that is in contact with the tip ridge line portion of the elastic blade,
The elastic blade is composed of a base material and a surface layer formed on a surface including a tip ridge portion of the base material,
The base material is composed of urethane rubber having an equilibrium swelling ratio of 200% or more when immersed in cyclohexanone,
Having a mixed layer of the urethane rubber and acrylic / methacrylic resin in a portion including the tip ridge line portion of the substrate;
The cleaning blade according to claim 1, wherein the surface layer is made of an acrylic / methacrylic resin and is formed in a region including the entire front end surface of the base material and the front end ridge line portion of the lower surface of the base material.   2. The cleaning blade according to claim 1, wherein the region including the tip ridge line portion on the lower surface of the base material is in a range of 2 mm or more including the tip ridge line portion on the lower surface of the base material.   The cleaning blade according to claim 1, wherein the mixed layer is formed from the surface of the substrate to a depth of 50 μm or more and 300 μm or less.   The acrylic / methacrylic resin of the surface layer comprises a compound having a pentaerythritol triacrylate skeleton having a functional group equivalent molecular weight of 110 or less and a functional group number of 3 to 6 as a monomer component. The cleaning blade according to item 1.   The cleaning blade according to claim 4, wherein the acrylic / methacrylic resin of the surface layer further includes an acrylic monomer having a perfluoropolyether skeleton and a functional group number of 2 or more as a monomer component.   The cleaning according to any one of claims 1 to 5, wherein the acrylic / methacrylic resin forming the mixed layer includes an alicyclic acrylate having a functional group equivalent molecular weight of 200 or less and a functional group number of 2 as a monomer component. blade.   The cleaning according to any one of claims 1 to 6, wherein the urethane rubber is a urethane rubber having a rebound resilience at 23 ° C of 75% or more and a JIS-A hardness of 67 ° or less. blade.   In an image forming apparatus that finally transfers an image formed on an image carrier, which is a surface moving member, to a recording medium, the surface of the image carrier is contacted, and unnecessary deposits adhered to the surface are removed. An image forming apparatus comprising the cleaning blade according to claim 1 as a cleaning member.   The main body of the image forming apparatus that finally transfers the image formed on the surface-moving latent image carrier to a recording medium is detachable, and the latent image carrier is brought into contact with the surface as a member to be cleaned. A process cartridge in which a cleaning unit having a cleaning member for removing unnecessary deposits adhered on the surface and the latent image carrier are integrally supported, wherein the cleaning member is defined in any one of claims 1 to 7. A process cartridge according to claim 1.

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