Cleaning blade, cleaning unit, intermediate transfer unit, and image forming apparatus

Abstract

The present invention relates to a cleaning blade for an image carrier, a process cartridge, and an image forming apparatus, which can suppress an increase in torque even after the start of use of the image forming apparatus, and can obtain good cleaning properties even if high-concentration images are continuously printed. A cleaning blade that is in contact with the surface of a member to be cleaned and removes residues on the surface of the member to be cleaned is characterized by comprising a cleaning blade base body having an elastic cleaning blade base body, and a cleaning blade support member that supports the cleaning blade base body, the elastic cleaning blade substrate is provided with an edge layer and a coating layer arranged on a tip ridge portion abutting against the image bearing body. The maximum depth of penetration hmax of an indenter of a microhardness tester according to a nanoindentation hardness test at a position of the coating layer on the lower surface of the cleaning blade substrate at a distance of 100 [mu] m inward from a tip ridge portion is 4.0 [mu] m or more and 10.0 [mu] m or less.

Description

Technical Field

[0001] The present invention relates to a cleaning blade, a cleaning unit, an intermediate transfer unit, and an image forming apparatus. Background Art

[0002] Conventionally, in an electrophotographic image forming apparatus, a seamless belt is used as a component for various purposes. In recent full-color electrophotographic image forming apparatuses, an intermediate transfer belt method is used in which developed images of four colors, yellow, magenta, cyan, and black, are temporarily color-overlapped on an intermediate transfer belt and then transferred together onto a recording medium such as paper. As a cleaning means for removing residual toner adhering to the surface of the intermediate transfer belt, a cleaning blade composed of an elastic cleaning blade base made of polyurethane rubber or the like and a support member is widely used.

[0003] From the viewpoints of preventing an increase in torque, which is a force required to rotate the intermediate transfer belt, and reducing the frictional force with the intermediate transfer belt, lubricity is required in the above-described cleaning blade.

[0004] For example, in recent years, in the case of the above-described cleaning blade, in order to reduce the frictional force with an image carrier, a cleaning blade coated with a lubricant containing a fluorine-based compound has been used, and a cleaning blade in which the fluorine-based compound contained in the lubricant is vinylidene fluoride has been proposed (see Patent Documents 1 to 5). Further, in order to impart appropriate softness and hardness to the elastic cleaning blade base in the cleaning blade and prevent warping or scratch wear of the leading edge line portion in the cleaning blade, a cleaning blade has been proposed in which the Martens hardness of the surface at a position only 20 [μm] away from the leading edge line portion of the elastic cleaning blade base to the inside is 1.0 [N / mm 2 to 15.0 [N / mm 2 (see Patent Document 6). Further, in order to improve the sliding mobility of the cleaning blade, a cleaning blade coated with a dispersion liquid obtained by dispersing PMMA (polymethyl methacrylate) particles in a fluorine-based solvent has been proposed (see Patent Document 7).

[0005] An object of the present invention is to provide a cleaning blade that can suppress an increase in torque even immediately after the image forming apparatus starts to be used and can obtain good cleaning performance even when continuously printing high-concentration images such as full-solid images.

[0006] [Patent Document 1] Japanese Patent Laid-Open No. 2000-147972

[0007] [Patent Document 2] Japanese Patent Laid-Open No. 2004-101551

[0008] [Patent Document 3] Japanese Patent No. 3278733

[0009]

Patent Document 4

[0010]

Patent Document 5

[0011]

Patent Document 6

[0012]

Patent Document 7

[0013] The cleaning blade of the present invention as a means for solving the above problems is a cleaning blade having an elastic cleaning blade base body that abuts against the surface of a member to be cleaned and removes residues on the surface of the member to be cleaned. The elastic cleaning blade base body has an edge layer and a coating layer provided on a leading edge line portion that abuts against the image carrier. The maximum penetration depth hmax of the indenter of the microhardness tester based on the nanoindentation hardness test of the coating layer on the lower surface of the cleaning blade is 4.0 [μm] or more and 10.0 [μm] or less.

[0014] According to the present invention, a cleaning blade can be provided that can suppress an increase in torque even immediately after the start of use of an image forming apparatus, and can obtain good cleanability even when continuously printing high-concentration images such as full-solid images. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a schematic cross-sectional view of an embodiment of the cleaning blade of the present invention.

[0016] Figure 2 Shown is a state diagram of the cleaning blade of the present invention abutting against a body to be cleaned.

[0017] Figure 3 Shown is a schematic perspective view of an example of the cleaning blade of the present invention.

[0018] Figure 4 Shown is a schematic cross-sectional view of another example of the cleaning blade of the present invention.

[0019] Figure 5 Shown is a schematic cross-sectional view of an example of the image forming apparatus of the present invention.

[0020] Figure 6 Shown is a schematic diagram of an example of a method for forming a coating layer in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, Figure 4The embodiments of the present invention will be described by taking the cleaning blade shown as an example. The cleaning blade 62 is composed of a cleaning blade support member 621 and a cleaning blade base 622. The cleaning blade base 622 includes an elastic edge layer 622a, a base layer 622b, a contact portion 62c, and a coating layer 623 on at least a part of the contact edge including the contact edge in the contact portion 62c.

[0022] Further, hereinafter, the case where the intermediate transfer body is the member to be cleaned of the cleaning blade of the present invention will be described. Hereinafter, the "blade base in the cleaning blade" may sometimes be referred to as the "blade base".

[0023] [Cleaning blade]

[0024] One embodiment of the cleaning blade of the present invention is a cleaning blade for cleaning an intermediate transfer body, which has an edge layer and a coating layer. The maximum penetration depth hmax of the indenter on the lower surface of the blade of the coating layer provided at the front end portion in contact with the intermediate transfer body in the edge layer is 4.0 [μm] or more and 10.0 [μm] or less. Further, it may have other components as needed.

[0025] The cleaning blade of the present invention is a cleaning blade that removes residues attached to the intermediate transfer body by contacting the surface of the intermediate transfer body.

[0026] As the above residues, there is no particular limitation as long as they are substances attached to the surface of the intermediate transfer body and are the objects to be removed by the cleaning blade. For example, toner, lubricant, inorganic particles, organic particles, paper scraps, garbage, dust, or a mixture thereof can be cited.

[0027] In the cleaning means using the existing cleaning blade, due to the friction generated by the contact between the cleaning blade and the intermediate transfer body, the torque of the force required to rotate the intermediate transfer body increases, and there is a problem that the rotation of the intermediate transfer body stops. In addition, due to the above friction, the contact portion of the cleaning blade with the intermediate transfer body is worn, and the cleaning blade warps or toner leaks, resulting in a problem of poor cleaning.

[0028] In order to improve the sliding mobility of the above-mentioned cleaning blade, prevent the warping or torque increase of the cleaning blade, a process (touchup) of applying a metal soap such as zinc stearate or PMMA (polymethacrylic acid) particles to the front end of the above-mentioned cleaning blade as a lubricant is widely used. Usually, as the image forming apparatus operates, toner gradually accumulates between the above-mentioned cleaning blade and the above-mentioned image carrier, and the above-mentioned toner functions as a lubricant. Therefore, the above-mentioned lubricant only needs to exhibit lubricating characteristics within a very short period from the start of the operation of the image forming apparatus until the operation behavior of the cleaning blade becomes stable. However, the adhesion of the fine particles contained in the conventional lubricants to the base material is weak, and there is a problem that the particles detach from the above-mentioned cleaning blade before the operation behavior of the cleaning blade becomes stable.

[0029] In order to suppress the detachment of the above-mentioned fine particles from the cleaning blade, a known technique is to apply a lubricant composed of the above-mentioned fine particles and a bonding component for fixing the above-mentioned fine particles to the contact portion between the above-mentioned cleaning blade and the above-mentioned intermediate transfer body. Since the above-mentioned fine particles are made difficult to detach from the above-mentioned cleaning blade by the above-mentioned bonding component, it has the effect of preventing torque increase. However, since the above-mentioned lubricant easily accumulates on the above-mentioned cleaning blade, it becomes difficult for the front end of the above-mentioned cleaning blade to be exposed, the pressure applied to the contact portion with the above-mentioned intermediate transfer body decreases, and the cleaning performance deteriorates. This becomes more significant when the amount of toner flowing into the clamping portion between the above-mentioned cleaning blade and the above-mentioned intermediate transfer body is large, such as in continuous printing of a full solid image.

[0030] The inventors of the present invention have found through in-depth research that in the lubricant composed of the above-mentioned fine particles and the above-mentioned bonding component, by making the coating layer composed of the above-mentioned lubricant brittle, while continuously preventing torque increase, even if the coating layer at the front end of the above-mentioned cleaning blade is easily shaved off, the front end portion of the blade is exposed in advance, the pressure applied to the contact portion with the above-mentioned intermediate transfer body increases, and even when the amount of toner flowing into the clamping portion between the above-mentioned cleaning blade and the above-mentioned intermediate transfer body is large, such as in continuous printing of a full solid image, the cleaning performance can be maintained, and both torque increase prevention and cleaning performance can be achieved.

[0031] Therefore, in the present invention, a cleaning blade is provided which targets an intermediate transfer member and has an edge layer and a coating layer. The coating layer provided at the front end portion of the edge layer that abuts against the intermediate transfer member is composed of fine particles and a binder component. On the lower surface of the blade of the coating layer, the maximum indentation depth hmax of the indenter of a microhardness tester obtained by a nanoindentation hardness test at a position 100 μm away from the leading edge line portion toward the inside is 4.0 μm or more and 10.0 μm or less. Thus, even immediately after the image forming apparatus starts to be used, an increase in torque can be suppressed, and even in a case where a large amount of toner rushes into the nip portion with the intermediate transfer member as in continuous printing of a full solid image, a cleaning blade showing good cleanability can be obtained.

[0032] <Coating layer>

[0033] The above coating layer contains fine particles and a binder component incompatible with the above fine particles, and if necessary, also contains other components. The above coating layer refers to a layer provided at one end used as the front end of the above cleaning blade on the circumferential side surface of a blade base body described later. The above coating layer can be formed on at least a part of the abutting edge including the abutting edge where the above cleaning blade and the above intermediate transfer member abut against each other on the above blade base body, or can be formed on the entire above abutting edge, or can be formed on the entire surface of the above blade base body. Among them, it is preferable that the above coating layer is formed on the entire above abutting edge. In addition, the surface area of the blade base body where the above coating layer is not provided is sometimes referred to as an uncoated area.

[0034] Preferably, the average thickness of the above coating layer in the above cleaning blade is 0.5 μm or more and 10 μm or less. When the average thickness of the above coating layer is 0.5 [μm] or more, a sufficient sliding effect can be obtained, and when the average thickness of the above coating layer is 10 [μm] or less, an effect of maintaining cleanability due to the above coating layer becoming brittle can be obtained. As the average thickness in the above coating layer, the average value of the thickness [μm] measured at three or more places in the above coating layer can be adopted. As the measurement position of the average thickness in the above coating layer, the central portion in the above coating layer at a position 100 [μm] away from the end portion toward the inside can be cited, etc.

[0035] As a method for measuring the average thickness in the above coating layer, it can be measured by shaving a part of the above coating layer with a spatula or a cotton swab, etc., and performing shape measurement using a three-dimensional measuring machine such as a contact surface roughness meter (Surftest SJ - 500: manufactured by Mitutoyo) or a laser microscope (LEXTOLS4100: manufactured by Olympus Corporation).

[0036] Here, an embodiment and other embodiments of the cleaning blade of the present invention will be described with reference to the accompanying drawings. The use of the cleaning blade of the present invention is not limited to these embodiments. In addition, in each figure, the same reference numerals are given to the same structural parts, and the repeated description thereof may be omitted. In addition, the number, position, shape, etc. of the following constituent parts are not limited to this embodiment, and appropriate numbers, positions, shapes, etc. can be selected when implementing the present invention.

[0037] Figure 1 The figure shows a schematic cross-sectional view of an embodiment of the cleaning blade of the present invention. Figure 2 The figure shows a state where the above cleaning blade is in contact with the surface of the above intermediate transfer body. Figure 3 is Figure 1 The figure shows a perspective view of the cleaning blade shown and an enlarged view of the vicinity of the contact portion. The cleaning blade 62 includes: a flat cleaning blade support member 621 made of a rigid material such as metal or hard plastic, and a flat cleaning blade base body 622 having one end connected to the above cleaning blade support member 621 and a free end with a predetermined length at the other end. The above cleaning blade base body 622 is fixed to one end of the above cleaning blade support member 621 by an adhesive or the like, and the other end of the cleaning blade support member 621 is supported on the housing of the cleaning device in a cantilever manner. The above cleaning blade base body 622 includes a cleaning blade front face 62a, a cleaning blade lower surface 62b, a cleaning blade contact portion 62c at one end on the free end side of the cleaning blade base body 622, and a cleaning blade side face 62d, and has a coating layer 623 on at least a part of the contact edge in the above cleaning blade contact portion 62c. The above cleaning blade 62 is configured such that the cleaning blade contact portion 62c contacts the surface of the above intermediate transfer belt 22 along the long side direction.

[0038] Figure 4 The figure shows a schematic cross-sectional view of another embodiment of the cleaning blade of the present invention. The cleaning blade 62 is composed of a cleaning blade support member 621 and a cleaning blade base body 622. The above cleaning blade base body 622 includes an elastic edge layer 622a, a base layer 622b, a contact portion 62c, and a coating layer 623 on at least a part of the contact edge in the above contact portion 62c. In addition, the cleaning blade front face 62a, the cleaning blade lower surface 62b, and the cleaning blade side face 62d are omitted.

[0039] The coating layer in the present invention is composed of particles and a resin as a binder component. As one aspect of the present invention, the above particles are preferably in the domain of the sea-island structure of the above coating layer. The above particles are preferably selected in terms of the type and addition amount of the particles according to the type of the resin of the binder component to form a domain.

[0040] The shape of the above particles is not particularly limited and can be appropriately selected according to the purpose. It can be a definite shape or an indefinite shape. Among them, a definite shape is preferred. When the shape in the above field is a definite shape, a spherical shape is preferred. With such a shape, it is possible to prevent problems such as damage to the intermediate transfer body and the blade base of the cleaning blade by the particles detached from the above coating layer, so it is preferred.

[0041] The volume average particle diameter (50% volume diameter, median diameter) of the above particles is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.1 [μm] or more and 1 [μm] or less, more preferably 0.1 [μm] or more and 0.5 [μm] or less, and further preferably 0.1 [μm] or more and 0.3 [μm] or less. When the volume average particle diameter of the above particles is 1 μm or less, it is possible to prevent problems such as easy sedimentation in the solvent and difficulty in stable dispersion. In addition, when the volume average particle diameter of the above particles is 0.5 [μm] or less, it can be more stably dispersed in the non-aqueous solvent.

[0042] The method for measuring the above volume average particle diameter (50% volume diameter, median diameter) is not particularly limited and can be appropriately selected according to the purpose. For example, it can be measured by laser diffraction / scattering method, dynamic light scattering method, image imaging method, etc. Specific examples of the method for measuring the above volume average particle diameter include a method of putting the particles collected from the coating layer of the above cleaning blade into Microtrac (manufactured by Nikkiso Co., Ltd.) and measuring by laser diffraction / scattering method, and a method of directly observing the fine particles on the cleaning blade using a scanning electron microscope (SEM) for measurement. In addition, the volume average particle diameter of the particles hardly changes when added to the dispersion liquid coated on the cleaning blade and when present in the coating layer.

[0043] The content of the above particles in the above coating layer is not particularly limited and can be selected according to the purpose. However, from the viewpoints of obtaining a sliding effect and making the above coating layer brittle due to being relatively more than the binder component and the above particles being easily detached, it is preferably 80% by mass or more and 99% by mass or less, more preferably 90% by mass or more and 98% by mass or less, based on the total mass of the above coating layer.

[0044] The material of the above particles is not particularly limited and can be selected according to the purpose. For example, polytetrafluoroethylene (PTFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), chlorotrifluoroethylene copolymer (CTFE), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE / CTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), etc. can be cited. Among them, from the viewpoint of further improving the sliding mobility of the cleaning blade, polytetrafluoroethylene (PTFE) is preferred.

[0045] The above-mentioned polytetrafluoroethylene (PTFE) can be appropriately synthesized or commercially available products can be used. As commercially available products of the above-mentioned polytetrafluoroethylene (PTFE), for example, DyneonTFMicroPowderTF-9201Z, DyneonTFMicroPowderTF-9207Z (both manufactured by 3M Company), NanoFLON119N, FLUOROE (both manufactured by Shamrock Company), TLP10F-1 (manufactured by Mitsui-DuPont Fluorochemical Company), KTL-500F (manufactured by Kitamura Co., Ltd.), AlgoflonL203F (manufactured by SOLVAY Company), etc. can be cited.

[0046] In the present invention, by containing a bonding component in the above-mentioned coating layer, the adhesion of the above-mentioned particles to the cleaning blade substrate can be improved, and the detachment of the above-mentioned coating layer can be prevented. Therefore, warping of the cleaning blade and an increase in torque can be prevented. As one aspect of the present invention, the above-mentioned bonding component is preferably the matrix in the sea-island structure possessed by the above-mentioned coating layer. The above-mentioned bonding component is preferably selected in terms of the type and addition amount of the resin with the above-mentioned particles to form a matrix.

[0047] As the above-mentioned bonding component, as long as it can uniformly and stably disperse the above-mentioned particles, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, vinylidene fluoride (VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), etc. can be cited. Among them, from the viewpoints of lubricity and close contact with the blade substrate, a copolymer combining them is preferred, and a terpolymer of VdF-HFP-TFE is more preferred.

[0048] From the viewpoints of imparting flexibility to the blade and solubility in a solvent, the composition of VdF / HFP / TFE in the above-mentioned terpolymer is preferably 30 mol% to 80 mol% / 10 mol% to 35 mol% / 5 mol% to 35 mol% in terms of their respective monomer units.

[0049] The above-mentioned particles and the above-mentioned bonding component are not limited to the examples shown above, and can be appropriately selected according to the purpose. For example, fine particles of inorganic compounds, acrylic resins, styrene resins, vinyl resins, etc. can be cited. As the fine particles of the above-mentioned inorganic compounds, silica, alumina, zirconia, etc. can be listed. These can be used alone as one kind or in combination of two or more kinds.

[0050] The coating layer is preferably a coating film composed of PTFE particles and a fluororesin, or a coating film composed of acrylic particles and a polyvinyl alcohol resin or a polyvinyl acetal resin.

[0051] As particles other than the above fluororesin, acrylic resins are preferred because they have a certain degree of hardness and can be expected to have the effect of sliding mobility. On the other hand, there is no particular limitation on the shape, which can be appropriately selected according to the purpose, and spherical shape is preferred. With such a shape, it is possible to prevent the particles other than the above fluororesin detached from the coating layer from damaging the intermediate transfer body or the blade substrate in the cleaning blade, so it is preferred.

[0052] The volume average particle diameter (50% volume diameter, median diameter) of the particles other than the above fluororesin is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.1 [μm] or more and 1 [μm] or less, more preferably 0.5 [μm] or less, and further preferably 0.3 [μm] or less. When the volume average particle diameter of the above particles is 1 μm or less, problems such as easy sedimentation in the solvent and difficult stable dispersion can be prevented. In addition, when the volume average particle diameter of the above particles is 0.5 [μm] or less, they can be more stably dispersed in the non-aqueous solvent.

[0053] There is no particular limitation on the method for manufacturing the above coating layer, which can be appropriately selected according to the purpose. For example, it can be obtained by adding particles to a mixture of a solvent and a binder component and coating the resulting particle dispersion on the blade substrate in the above cleaning blade.

[0054] There is no particular limitation on the above solvent, which can be appropriately selected according to the purpose. For example, in the case of fluorine-based particles and a binder component, fluorine-containing organic solvents can be cited. As the above fluorine-containing organic solvents, for example, hydrofluoroether (HFE), perfluorocarbon (PFC), perfluoroether (PFE), etc. can be cited. These materials can be used alone as one kind or in combination of two or more kinds.

[0055] In the present invention, from the viewpoint of obtaining a uniform dispersion, the average particle diameter (average particle diameter in the cumulative amount analysis in the scattering intensity distribution) by the dynamic light scattering method of the particles in the above binder component is preferably 1 μm or less, more preferably 0.5 μm or less, and further preferably 0.3 μm or less. Generally, even when using fine particles with a volume average particle diameter of 1 [μm] or less, secondary particles are formed by particle aggregation, and the above volume average particle diameter becomes fine particles of 1 [μm] or more. By dispersing the fine particles aggregated to form secondary particles into particles with a diameter of 1 [μm] or less, a stable dispersion can be obtained even when the above fluororesin dispersion is stored for a long time at a low viscosity. There is no particular limitation on the dispersion method, which can be appropriately selected according to the purpose. For example, methods using dispersers such as ultrasonic dispersers, three-roll mills, ball mills, bead mills, jet mills, etc. can be cited.

[0056] As a method for forming the above-mentioned coating layer, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, dipping in which the entire blade base body of the above-mentioned cleaning blade or a part of the above-mentioned blade base body is immersed in a particle dispersion for treatment can be cited. In addition to the above-mentioned dipping, coating methods such as spray coating and dispenser can also be used.

[0057] <Blade base body>

[0058] In the present invention, the blade base body in the above-mentioned cleaning blade is sometimes referred to as the "blade base body" or the "base body". As the shape of the above-mentioned blade base body, any structure that can remove the above-mentioned residue on the above-mentioned intermediate transfer body can be appropriately selected according to the purpose, but preferably, the contact edge in the contact portion between the above-mentioned blade base body and the above-mentioned intermediate transfer body is linear. As the shape of the above-mentioned blade base body, for example, a plate shape can be cited.

[0059] As the structure of the above-mentioned blade base body, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, a single-layer structure, a laminated structure, and a laminated structure formed by combining multiple components can be cited. Among them, from the viewpoint of being easily processed into the above-mentioned cleaning blade, a single-layer structure and a laminated structure formed by laminating multiple components are preferred. When the above-mentioned blade base body has a laminated structure, the layer in contact with the above-mentioned intermediate transfer body is sometimes referred to as the edge layer, and the layer that is not the above-mentioned edge layer is referred to as the base layer. In addition, when the above-mentioned blade base body is single-layer, the above-mentioned blade base body only has an edge layer. More preferably, the Martens hardness of the multiple components in the above-mentioned laminated structure is different from each other.

[0060] As the material of the above-mentioned blade base body, there is no particular limitation, and it can be appropriately selected according to the purpose. However, from the viewpoints of preventing wear of the above-mentioned blade base body and sufficiently removing the above-mentioned residue on the above-mentioned intermediate transfer body, it is preferably moderately elastic and hard. As the material of the above-mentioned blade, for example, an elastic material can be cited. As the above-mentioned elastic material, as long as it is highly elastic, there is no particular limitation, and it can be appropriately selected according to the purpose. Polyurethane rubber, silicone rubber, fluororubber, nitrile rubber (NBR), ethylene propylene diene monomer rubber (EPDM), etc. can be cited. Among them, from the viewpoints of durability and non-pollution, polyurethane rubber is preferred.

[0061] As the size of the above-mentioned blade base body, there is no particular limitation, and it can be appropriately selected according to the size of the above-mentioned intermediate transfer body.

[0062] The Martens hardness of the above-mentioned polyurethane rubber in the cleaning blade of the present invention is not particularly limited and can be appropriately selected according to the purpose. It is preferably 0.5 [N / mm 2 or more and 2 [N / mm 2As described below, by setting the Shore hardness of the polyurethane rubber in the above-described cleaning blade within a desired range, it becomes possible to eliminate problems such as poor cleaning caused by difficulty in obtaining the blade line pressure and the tendency of the area of the contact portion with a member such as a carrier to increase, and defects caused by the blade base becoming too hard.

[0063] As a method for manufacturing the above-described blade base, there are no particular limitations, and it can be appropriately selected according to the purpose. For example, a polyurethane prepolymer can be prepared by using a polyol compound and a polyisocyanate compound, and a curing agent is added to the polyurethane prepolymer, and a curing catalyst is added as needed. Then, centrifugal molding is performed using a specified mold, and after leaving it at room temperature to complete (cure), the resulting product is cut into a flat plate shape with a specified size to obtain the blade base.

[0064] There are no particular limitations on the above-described polyol compound, and it can be appropriately selected according to the purpose. Examples thereof include high molecular weight polyols and low molecular weight polyols.

[0065] Examples of the above-described high molecular weight polyols include polyester polyols such as condensates of alkylene glycols and aliphatic dicarboxylic acids, such as ethylene glycol adipate polyol, butanediol adipate polyol, hexanediol adipate polyol, ethylene glycol propylene glycol adipate polyol, ethylene glycol butanediol adipate polyol, and ethylene glycol neopentyl glycol adipate polyol; polycaprolactone polyols such as polycaprolactone polyols obtained by ring-opening polymerization of caprolactone; and polyether polyols such as poly(tetramethylene oxide) glycol and poly(propylene oxide) glycol. These can be used alone or in combination of two or more.

[0066] Examples of the above-described low molecular weight polyols include diols such as 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis(2-hydroxyethyl) ether, 3,3'-dichloro-4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane; and trihydric or higher polyols such as 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, 1,1,1-tris(hydroxyethoxymethyl)propane, diglycerin, and pentaerythritol. These can be used alone or in combination of two or more.

[0067] As the above polyisocyanate compound, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, methylene diphenyl diisocyanate (MDI), dimethylbiphenyl diisocyanate (TDI), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), tetramethylxylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), etc. can be cited. These can be used alone as one kind or in combination of two or more kinds.

[0068] As the above curing agent, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, amines, alcohols, etc. can be cited. These can be used alone as one kind or in combination of two or more kinds. The above curing agent is used, for example, to adjust the hardness of the above squeegee base.

[0069] The above curing catalyst is not particularly limited and can be appropriately selected according to the intended purpose. For example, 2-methylimidazole, 1,2-dimethylimidazole, etc. can be cited. The content of the above curing catalyst is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 0.01% by mass or more and 0.5% by mass or less, more preferably 0.05% by mass or more and 0.3% by mass or less, based on the total mass of the prepolymer and the curing agent.

[0070] As the resilience modulus of elasticity of the above squeegee base according to JIS K6255 standard, there is no particular limitation and it can be appropriately selected according to the purpose. It is preferably 10% to 80% at 23°C. By making the above resilience modulus of elasticity within the desired range, it is possible to eliminate the poor cleaning caused by the disappearance of the softness of the entire above squeegee base and the inability to follow the vibration or roughness of the carrier, or the poor condition of squeegee ringing (abnormal sound) caused by excessive resilience. The resilience coefficient of the above squeegee base can be measured, for example, according to the JIS K6255 standard at 23°C using an No. 221 elastic testing machine manufactured by Toyo Seiki Seisaku-sho, Ltd.

[0071] <Maximum indentation depth hmax of the indenter>

[0072] In the cleaning blade of the present invention, the maximum indentation depth hmax of the indenter at a position 100 [μm] away from the tip ridge line portion toward the inside is 4.0 [μm] or more and 10.0 [μm] or less. Thus, the effect that the above-mentioned coating layer is easily broken can be sufficiently obtained. From the viewpoint of being able to balance the sliding effect and the cleaning performance brought about by the easy breakage of the film, hmax at a position 100 [μm] away from the tip ridge line portion of the above-mentioned edge layer toward the inside in the cleaning blade of the present invention is preferably 5.5 [μm] or more and 7.5 [μm] or less. When hmax at a position 100 [μm] away from the tip ridge line portion of the above-mentioned edge layer toward the inside in the above-mentioned cleaning blade is 4.0 [μm] or more, since the above-mentioned coating layer is easily broken, the problem of maintaining the cleaning performance even when continuously printing high-concentration images can be eliminated, so it is preferable. If hmax at a position 100 [μm] away from the tip ridge line portion of the above-mentioned edge layer toward the inside in the above-mentioned cleaning blade is less than 4.0 [μm], since the above-mentioned coating layer is difficult to break, the cleaning performance cannot be maintained when continuously printing high-concentration images. On the contrary, if hmax exceeds 10.0 [μm], the sliding mobility cannot be maintained because the above-mentioned coating layer is too easily broken, or a bad situation where the coating layer falls off from the cleaning blade by itself when not in use may occur. In addition, the measurement of the Martens hardness in the present invention is carried out after processing into a cleaning blade.

[0073] -Measurement of the maximum indentation depth hmax of the indenter-

[0074] The maximum indentation depth hmax of the above-mentioned indenter is measured, for example, based on ISO14577, using a nanoindenter (ENT-3100, manufactured by Elionix Corporation), pressing a Berkovich indenter with a load of 1,000 [μN] for 10 seconds, holding for 5 seconds, and pulling out at the same load speed for 10 seconds, and hmax is calculated from the load-displacement curve. As the measurement position of the above-mentioned edge layer, as Figure 4 shown, it is a position 100 [μm] away from the tip ridge line portion (62c) of the above-mentioned edge layer toward the inside. In addition, the load speed starts from 0 μN, increases the load at a constant speed in 10 seconds, and reaches 1000 μN after 10 seconds.

[0075] <Measurement of Martens hardness>

[0076] There is no particular limitation on the measurement position of the Martens hardness in the base layer of the above-mentioned cleaning blade. From the viewpoint of ease of measurement, it is set as a position 100 [μm] away from the end of the above-mentioned base layer toward the inside. In addition, the above-mentioned Martens hardness is the median value of the values obtained by measuring 4 to 6 points at each measurement position. In addition, the measurement conditions are the same as those in the measurement of the "maximum indentation depth hmax of the indenter" above.

[0077] <Intermediate transfer body>

[0078] The intermediate transfer body of the present invention transfers a toner image obtained by developing a latent image formed on an image carrier with toner, and includes an intermediate transfer belt, a secondary transfer belt, etc. It contains a resin and a resistance adjuster, and further contains other components as required.

[0079] - Resin -

[0080] As the above resin, from the viewpoint of flame retardancy, for example, fluorine-based resins such as PVDF and ETFE can be cited; polyimide resins, polyamide-imide resins, etc. Among them, from the viewpoints of mechanical strength (high elasticity) and heat resistance, polyimide resins or polyamide-imide resins are preferred. As the above polyimide resin or polyamide-imide resin, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, general-purpose products obtained from manufacturers such as Toray DuPont Co., Ltd., Ube Industries, Ltd., Shin Nippon Rika Co., Ltd., JSR Corporation, UNITIKA Ltd., ITS Co., Ltd., Hitachi Chemical Co., Ltd., Toyobo Co., Ltd., Arakawa Chemical Industries Co., Ltd. can be used.

[0081] - Resistance adjuster -

[0082] As the above resistance adjuster, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, metal oxides, carbon black, ion conductive agents, conductive polymers, etc. can be cited. As the above metal oxides, for example, zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, silicon oxide, etc. can be cited. In addition, in order to improve dispersibility, substances obtained by pre-treating the above metal oxides with surface treatment can be cited. As the above carbon black, for example, Ketjen black, furnace black, acetylene black, thermal cracking carbon black, gas black, etc. can be cited. As the above ion conductive agents, for example, tetraalkylammonium salts, trialkylbenzylammonium salts, alkyl sulfonates, alkylbenzenesulfonates, alkyl sulfates, glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty alcohol esters, alkyl betaines, and lithium perchlorate can be cited. As the above conductive polymers, for example, poly(p-phenylene), polyaniline, polythiophene, poly(p-phenylene vinylene), etc. can be cited. The above resistance adjuster can be used alone as one kind, or two or more kinds can be used in combination.

[0083] The content of the above resistance adjuster in the base layer of the above intermediate transfer body is not particularly limited and can be appropriately selected according to the purpose. However, when the resistance adjuster is the above carbon black, it is preferably 10% by mass or more and 25% by mass or less, more preferably 15% by mass or more and 20% by mass or less, relative to the above base layer. In addition, when the resistance adjuster is the above metal oxide, it is preferably 1% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 30% by mass or less, relative to the above base layer. When the above content is at least the lower limit value of the above preferred range, the effect of adjusting the resistance can be obtained, and when it is below the upper limit value of the above preferred range, good mechanical strength of the intermediate transfer belt can be obtained.

[0084] - Other components -

[0085] Examples of the above other components include dispersion aids, reinforcing agents, lubricants, heat conductors, antioxidants, etc.

[0086] The average thickness of the above base layer is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 30 μm or more and 150 μm or less, more preferably 40 μm or more and 120 μm or less, and particularly preferably 50 μm or more and 80 μm or less. When the average thickness of the above base layer is 30 μm or more and 150 μm or less, it is advantageous for the durability of the intermediate transfer belt. In addition, regarding the above base layer, in order to improve the running stability, it is preferable to eliminate the thickness unevenness as much as possible. As the method for measuring the average thickness of the above base layer, there is no particular limitation and it can be appropriately selected according to the purpose. For example, it includes measurement using a contact type or eddy current type film thickness gauge, a method of measuring the cross section of the film using a scanning electron microscope (SEM), etc.

[0087] [Image forming apparatus and image forming method]

[0088] The image forming apparatus of the present invention at least has an image carrier, a charging means for charging the surface of the above image carrier, an exposure means for exposing the charged above image carrier to form an electrostatic latent image, a developing means for developing the above electrostatic latent image using toner to form a visible image, a transfer means for transferring the above visible image to a recording medium via an intermediate transfer body, a fixing means for fixing the transferred image on the above recording medium, and a cleaning means for removing the toner remaining on the above intermediate transfer body. Further, according to need, it may also have other means appropriately selected. The above charging means and the above exposure means are sometimes collectively referred to as an electrostatic latent image forming means. In addition, the above cleaning means each has a cleaning blade of the present invention.

[0089] The image forming method used in the present invention at least includes a charging step, an exposure step, a developing step, a transfer step, a fixing step, and a cleaning step. Further, other appropriately selected steps are included as needed. In addition, the above charging step and the above exposure step are sometimes together referred to as an electrostatic latent image forming step.

[0090] The image forming method used in the present invention can be appropriately implemented by the image forming apparatus of the present invention. The above charging step can be carried out by the above charging means, the above exposure step can be carried out by the above exposure means, the above developing step can be carried out by the above developing means, the above transfer step can be carried out by the above transfer means, the above fixing step can be carried out by the above fixing means, the above cleaning step can be carried out by the above cleaning means, and the above cleaning means has the cleaning blade of the present invention. The above other steps can be carried out by the above other means.

[0091] <Image carrier>

[0092] As the above image carrier, there are no particular limitations on its structure, size, etc., and it can be appropriately selected from known ones. There are no particular limitations on the shape of the above image carrier, and it can be appropriately selected according to the purpose. For example, drum-shaped, belt-shaped, etc. can be cited. As the material of the above image carrier, there are no particular limitations and it can be appropriately selected according to the purpose. Examples include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalocyanine polyene. As the above organic photoreceptor, a laminated photoreceptor having a laminated structure on a support such as an aluminum drum can be cited. The laminated structure is laminated with a layer (charge generation layer) in which a charge generation material such as metal-free phthalocyanine or titanyl phthalocyanine is dispersed in a binder resin and a layer (charge transport layer) in which a charge transport material is dispersed in a binder resin, and a single-layer photoreceptor having a photosensitive layer with a single-layer structure in which both a charge generation material and a charge transport material are dispersed in a binder resin on a support. In the single-layer photoreceptor, a hole transport agent and an electron transport agent can also be added to the photosensitive layer as the charge transport material.

[0093] In addition, a primer layer can be provided between the support and the laminated charge generation layer or the single-layer photosensitive layer.

[0094] <Charging step and charging means>

[0095] The above charging process is a process of charging the surface of the above image carrier, which is carried out by the above charging means. As the above charging means, there are no particular limitations as long as it can charge the surface of the above image carrier, and it can be appropriately selected according to the purpose. For example, known contact chargers including conductive or semiconductive rollers, brushes, film materials, rubber scrapers, etc. can be cited, as well as non-contact chargers using corona discharge of corona tubes, corona wires, etc.

[0096] As the shape of the above charging means, for example, it can be any form such as a roller, a magnetic brush, a brush, etc., and can be selected according to the specifications and forms of the electrophotographic image forming apparatus. In the case of using a magnetic brush, the above magnetic brush uses various ferrite particles such as Zn-Cu ferrite as the charging means, and is constituted by a non-magnetic conductive sleeve for supporting the above charging means and a magnetic roller contained in the above conductive sleeve.

[0097] In the case of using a brush, for example, hair that has been subjected to conductive treatment with carbon, copper sulfide, metal or metal oxide can be used as the material of the brush, and the charger can be manufactured by winding or pasting it onto a metal or other conductively treated mandrel.

[0098] The above charger is not limited to the above contact charger, but is preferred from the viewpoint of an image forming apparatus that reduces ozone generated by the charger. The above charger is preferably arranged in contact or non-contact with the image carrier, and the surface of the image carrier is charged by overlapping application of a DC voltage and an AC voltage. In addition, it is preferred that the above charger is a charging roller arranged adjacent to the image carrier in a non-contact manner with a spacing belt therebetween, and the surface of the image carrier is charged by overlapping application of a DC voltage and an AC voltage to the above charging roller.

[0099] <Exposure process and exposure means>

[0100] The above exposure process is a process of exposing the surface of the charged above image carrier, which is carried out by the above exposure means. The above exposure can, for example, use the above exposure means to expose the surface of the above image carrier to generate an image. The optical system in the above exposure is roughly divided into an analog optical system and a digital optical system. The above analog optical system is an optical system that directly projects an original onto the surface of the above image carrier through an optical system. The above digital optical system is an optical system that receives image information as an electrical signal, converts the above electrical signal into an optical signal, and exposes the image carrier to form an image.

[0101] As the above-described exposure means, as long as it can expose the above-described charged image carrier to form an electrostatic latent image, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system can be cited. In addition, in the present invention, an optical backside method of exposing in an image manner from the back side of the image carrier can also be adopted.

[0102] <Developing Step and Developing Means>

[0103] The above-described developing step is a step of developing the above-described electrostatic latent image into the above-described toner image, and is performed by the above-described developing means. As the above-described developing means, as long as it can develop the above-described electrostatic latent image into a toner image, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, a developing means having at least a developer that houses the above-described toner and can apply the above-described toner to the above-described electrostatic latent image in a contact or non-contact manner can be cited. The above-described developer can be either a dry developing method or a wet developing method, and can be either a single-color developer or a multi-color developer. For example, a developer including a stirrer that rubs and stirs the above-described toner to charge it and a rotatable magnetic roller can be cited. In the above-described developer, for example, the above-described toner and, if necessary, a carrier are mixed and stirred, and the above-described toner is charged by the friction at this time and is held in an upright state on the surface of the rotating above-described magnetic roller to form a magnetic brush. Since the above-described magnetic roller is disposed near the above-described image carrier, a part of the above-described toner that constitutes the above-described magnetic brush formed on the surface of the above-described magnetic roller moves to the surface of the above-described image carrier by the electrostatic attraction of the above-described electrostatic latent image. As a result, the above-described electrostatic latent image is developed by the above-described toner, and a toner image is formed on the surface of the above-described image carrier. The toner housed in the above-described developer can be a developer including the above-described toner, and the above-described developer can be either a single-component developer or a two-component developer. In addition, the above-described toner can also be used as a single-component magnetic toner or a non-magnetic toner that does not use a carrier.

[0104] As a developing method, a pre-mixed developing method of supplying a pre-mixed developer in which a toner and a carrier are pre-mixed can also be adopted. In the pre-mixed developing method, the amount of the carrier increased in the developing device is discharged as a remaining developer. Thereby, the developer in the developing device is gradually updated. Thereby, the replacement cycle accompanying the deterioration of the developer can be extended, or the time for replacing the developer can be saved.

[0105] <Transfer Step and Transfer Means>

[0106] The above transfer process is a process of transferring the above toner image onto a recording medium, and is performed by transfer means. As the above transfer process, it preferably includes, for example, a primary transfer process of transferring the above toner image onto the surface of the intermediate transfer body using the intermediate transfer body to form a composite transfer image, and a secondary transfer process of transferring the above composite transfer image onto the recording medium. As the above transfer process, as long as it can transfer the above toner image onto the recording medium, there is no particular limitation, and it can be appropriately selected according to the purpose. It preferably has a primary transfer means of transferring the above toner image onto the surface of the intermediate transfer body to form a composite transfer image, and a secondary transfer means of transferring the above composite transfer image onto the recording medium. As the above primary transfer means and the above secondary transfer means, for example, it is preferably to have at least a transfer device that makes the above toner image formed on the surface of the image carrier peeled and charged onto the recording medium. There is no particular limitation on the above transfer device, and it can be appropriately selected according to the purpose. For example, a corona discharge transfer device by corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, an adhesive transfer device, etc. can be cited. The above transfer device can be one or two or more.

[0107] As the above recording medium, as long as it can transfer the unfixed developed above toner image, there is no particular limitation, and it can be appropriately selected according to the purpose. Representative is plain paper, and for example, a PET substrate for OHP can also be used.

[0108] <Fixing Process and Fixing Means>

[0109] The above fixing process is a process of fixing the above toner image transferred onto the above recording medium, and is performed by the above fixing means. In addition, in the case of using two or more colors of toner, fixing can be performed each time the toner of each color is transferred onto the recording medium, or fixing can be performed in a state where the toner of all colors is transferred onto the recording medium and laminated. As the above fixing means, as long as it can fix the above toner image transferred onto the above recording medium, there is no particular limitation, and it can be appropriately selected according to the purpose, and a heat fixing method using known heating and pressing means can be adopted. There is no particular limitation on the above heating and pressing means, and it can be appropriately selected according to the purpose. For example, a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller and an endless belt, etc. can be cited. There is no particular limitation on the heating temperature, and it can be appropriately selected according to the purpose. Preferably, it is 80°C to 200°C. In addition, if necessary, a known light fixing device can also be used together with the above fixing means.

[0110] <Cleaning Process and Cleaning Means>

[0111] The above cleaning process is a process for removing the toner remaining on the surface of the intermediate transfer body, and is performed by a cleaning means. As the above cleaning means, a means of fixing the cleaning blade of the present invention to a support member is used.

[0112] The line pressure applied by the blade base of the cleaning blade of the present invention to the surface of the image carrier is not particularly limited and can be appropriately selected according to the purpose. It is preferably 10 [N / m] or more and 100 [N / m] or less, and more preferably 10 [N / m] or more and 50 [N / m] or less. When the line pressure is 10 [N / m] or more and 100 [N / m] or less, it is difficult for poor cleaning to occur due to the toner leaking from between the contact portion and the intermediate transfer body, and the warping of the elastomer can be easily suppressed. In addition, the line pressure can be measured, for example, using a measuring device equipped with a small compression type load cell manufactured by Kyowa Electronic Instruments Co., Ltd.

[0113] The angle (hereinafter referred to as "cleaning angle") formed by the tangent of the image carrier at the position where the contact portion of the blade base of the cleaning blade of the present invention contacts and the front end surface of the free end of the blade base is not particularly limited and can be appropriately selected according to the purpose. It is preferably 65° or more and 85° or less. When the cleaning angle is 65° or more and 85° or less, the occurrence of warping of the blade base can be easily suppressed, and the occurrence of poor cleaning can be easily reduced.

[0114] <Other Processes and Other Means>

[0115] As the above other processes, for example, a charge removal process, a recovery process, a control process, etc. can be cited. As the above other means, for example, a charge removal means, a recovery means, a control means, etc. can be cited.

[0116] (Charge Removal Process and Charge Removal Means)

[0117] The above charge removal process is a process for removing charge by applying a charge removal bias voltage to the image carrier, and can be performed by the above charge removal mechanism. As the above charge removal means, as long as it can apply a charge removal bias voltage to the image carrier, there is no particular limitation and it can be appropriately selected according to the purpose. For example, a charge removal lamp can be cited.

[0118] (Recovery Process and Recovery Means)

[0119] The above recovery process is a process for recovering the toner removed by the above cleaning process into the developing unit, and can be performed by the above recovery unit. There is no particular limitation on the above recovery mechanism, and it can be appropriately selected according to the purpose. Examples include well-known conveying mechanisms, etc.

[0120] (Control Process and Control Means)

[0121] The above control process is a process for controlling the above respective processes, and can be carried out by control means. As the above control means, as long as it can control the operations of the above respective processes, there is no particular limitation, and it can be appropriately selected according to the purpose. For example, a sequencer, a computer, etc. can be cited.

[0122] Here, an example of the image forming apparatus in the present invention will be described with reference to the accompanying drawings. Among them, the use of the cleaning blade of the present invention is not limited to these embodiments.

[0123] In addition, in each figure, the same reference numerals are given to the same structural parts, and sometimes the repeated description thereof will be omitted. In addition, the number, position, shape, etc. of the following constituent parts are not limited to this embodiment, and appropriate numbers, positions, shapes, etc. can be selected when implementing the present invention.

[0124] Figure 5 Shown is a schematic configuration example of the image forming apparatus of the present invention. The image forming apparatus includes four image forming units for yellow, magenta, cyan, and black (hereinafter sometimes referred to as Y, M, C, BK). As the image forming substances for forming images, they use Y, M, C, BK toners of different colors, but the other configurations are the same.

[0125] Each image forming unit includes respectively: a photosensitive drum 21 (a photosensitive drum 21C for cyan, a photosensitive drum 21Y for yellow, a photosensitive drum 21M for magenta, and a photosensitive drum 21BK for black); a charging unit for uniformly charging the photosensitive drum 21; an exposure device 12 for exposing the photosensitive drum 21 according to the image information of each color and forming a latent image of each color on the photosensitive drum 21; a developing device 20 as a developing unit for developing the latent image with a developer of each color to form a toner image of each color (a developing device 20C for cyan, a developing device 20Y for yellow, a developing device 20M for magenta, and a developing device 20BK for black); a transfer charger for transferring the toner image to the intermediate transfer belt 22; a cleaning device 13; and a pre-exposure lamp.

[0126] The charging unit is a charging component included in the charging device as a charging means, and the developing device 20 is a developing means for toner-developing the latent image formed on the surface of the photosensitive drum 21. The cleaning device 13 is a cleaning means for cleaning the toner remaining on the photosensitive drum 21 after the toner image is transferred to the intermediate transfer belt 22. The pre-exposure lamp (not shown) is a pre-exposure means for pre-exposing the surface potential of the cleaned photosensitive drum 21.

[0127] In addition, the photosensitive drum 21 is shown in a drum shape, but it can also be in a sheet shape or an annular belt shape.

[0128] Below each imaging unit, an intermediate transfer unit 80 is disposed. The intermediate transfer unit 80 has an intermediate transfer belt 22 as an intermediate transfer body. The intermediate transfer belt 22 is an endless belt tensioned by three rollers 26 and can move along the Figure 5 arrow direction in the figure. Near the intermediate transfer belt 22, transfer rollers 23 (a cyan transfer roller 23C, a yellow transfer roller 23Y, a magenta transfer roller 23M, and a black transfer roller 23BK) are disposed facing the intermediate transfer belt 22, and can apply a transfer bias (secondary transfer bias) for transferring (secondary transfer) the developed image (toner image) onto a recording paper P as a recording medium.

[0129] In addition, in the present embodiment, an elastic intermediate transfer belt may be used as the intermediate transfer belt 22. As the elastic intermediate transfer belt, for example, a belt in which a soft elastic layer is laminated on a rigid base layer capable of obtaining flexibility can be used.

[0130] Furthermore, in order to prevent the intermediate transfer belt 22 from meandering, an anti-offset guide member may be provided on the inner peripheral surface of the intermediate transfer belt 22.

[0131] Near the roller 26, an intermediate transfer body cleaning blade 25 for removing toner remaining on the intermediate transfer belt 22 after the toner image has been transferred onto the recording paper P, and a lubricant coating unit 27 as a mechanism for coating a lubricant (such as zinc stearate) on the intermediate transfer body are disposed. The intermediate transfer body cleaning blade 25 abuts against the intermediate transfer belt 22 in a direction opposite to the surface movement direction of the intermediate transfer belt 22. In addition, the details of the intermediate transfer body cleaning blade 25 are as described above.

[0132] A secondary transfer device is disposed on the side of the intermediate transfer belt 22 opposite to the side where the above-described imaging unit is disposed. The secondary transfer device includes a secondary transfer belt 50. In addition, the secondary transfer belt 50 is an endless belt tensioned by a pair of rollers 60, and can bring the recording paper P conveyed to the secondary transfer belt 50 through the paper feeding unit 14 and the registration rollers 16 into contact with the intermediate transfer belt 22 between the rollers 26 and 60. In addition, a fixing device 15 is disposed near the secondary transfer belt 50.

[0133] In addition, the cleaning unit 30 has a cleaning blade 6(2), and a collecting means is provided as needed to receive toner and the like removed by the lubricant coating unit 27 or the cleaning blade. As the collecting means, a dish-shaped tray or the like can be used.

[0134]

Example

[0135] The embodiments and reference examples of the present invention will be described below, but the present invention is not limited to these embodiments. Herein, "parts" means "parts by mass" unless otherwise specified.

[0136] Next, an embodiment Figure 4 in which the cleaning blade base shown is composed of an elastic edge layer and a base layer will be described.

[0137] (Preparation of the particle dispersion for forming the coating layer)

[0138] - Preparation of particle dispersion A -

[0139] 6.8 parts of polytetrafluoroethylene (PTFE) fine powder (TF9201Z, manufactured by 3M Company, volume average particle diameter 200 nm) as particles, 0.2 parts of a terpolymer of vinylidene fluoride (VdF), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE) as a binder component, and 93.0 parts of 1,1,2,2 - tetrafluoroethyl 2,2,2 - trifluoroethyl ether (HFE - 347, manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine - based dispersion solvent are put into a helical tube and stirred with a stirrer or the like to prepare [particle dispersion A].

[0140] - Preparation of particle dispersion B -

[0141] 6.9 parts of polytetrafluoroethylene (PTFE) fine powder (TF9201Z, manufactured by 3M Company, volume average particle diameter 200 nm) as particles, 0.1 parts of a terpolymer of VdF - HFP - TFE as a binder component, and 93.0 parts of 1,1,2,2 - tetrafluoroethyl 2,2,2 - trifluoroethyl ether (HFE - 347, manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine - based dispersion solvent are put into a helical tube and stirred with a stirrer or the like to prepare [particle dispersion B].

[0142] - Preparation of particle dispersion C -

[0143] 5.8 parts of polytetrafluoroethylene (PTFE) fine powder (TF9201Z, manufactured by 3M Company, volume average particle diameter 200 nm) as particles, 1.2 parts of a terpolymer of VdF - HFP - TFE as a binder component, and 93.0 parts of 1,1,2,2 - tetrafluoroethyl 2,2,2 - trifluoroethyl ether (HFE - 347, manufactured by Tokyo Chemical Industry Co., Ltd.) as a fluorine - based dispersion solvent are put into a helical tube and stirred with a stirrer or the like to prepare [particle dispersion C].

[0144] - Preparation of particle dispersion D -

[0145] 97.0 parts of an aqueous dispersion of polymethyl methacrylate (PMMA) (MX100W, manufactured by Nippon Shokubai Co., Ltd., volume average particle diameter: 150 nm) as particles and 3.0 parts of polyvinyl butyral (PVB) (S-Lec KW-10, manufactured by Sekisui Chemical Co., Ltd., degree of acetalization: 9 ± 2 mol%) as a binder component were placed in a helical tube and stirred with a stirrer or the like to prepare [particle dispersion D].

[0146] - Preparation of particle dispersion E -

[0147] 95.0 parts of an aqueous dispersion of polymethyl methacrylate (PMMA) (MX100W, manufactured by Nippon Shokubai Co., Ltd., volume average particle diameter 150 nm) as particles and 5.0 parts of a polyvinyl alcohol (PVA) resin (Poval JP-03, manufactured by Nippon Shokubai Co., Ltd., saponification degree 88 ± 2 mol%) as a binder component were placed in a helical tube and stirred with a stirrer or the like to prepare [particle dispersion E].

[0148] <Example 1>

[0149] (Fabrication of the blade base in the cleaning blade)

[0150] The edge layer and the base layer used a polyurethane elastomer sheet formed, cured, and post-crosslinked by centrifugal forming. In addition, the average thickness and the Martens hardness (HM) in the above-mentioned edge layer and the above-mentioned base layer are as follows.

[0151] Average thickness: 2.0 [mm]

[0152] Martens hardness (HM) of the edge layer: 0.5 [N / mm 2

[0153] Martens hardness (HM) of the base layer: 1.1 [N / mm 2

[0154] The blade base was fabricated by bonding the above-mentioned edge layer and the above-mentioned base layer. In addition, the above-mentioned blade base was bonded to a metal plate.

[0155] (Formation of the coating layer: impregnation)

[0156] One end surface used as the front end of the above-mentioned cleaning blade in the circumferential side surface (hereinafter, sometimes referred to as the cleaning blade front end surface) was immersed in the above-mentioned [particle dispersion A] at a depth of 2 [mm] from the horizontal plane and at a lifting speed of 1 [mm / s] so that the cleaning blade front end surface was perpendicular to the horizontal plane. In order to collect the PTFE particles required for the cleaning function into the portion including the above-mentioned contact edge in the above-mentioned cleaning blade front end surface, as​​Figure 6 As shown, the cleaning blade of Example 1 was produced by tilting it by about 45° and drying it at room temperature (25°C) for 30 minutes.

[0157] The average thickness of the coating layer was 0.5 μm.

[0158] <Examples 2 to 7, Comparative Examples 1 to 3>

[0159] Except that the type of the particle dispersion, the Martens hardness of the base layer, and the average thickness of the coating layer in Example 1 were changed as shown in Table 1, the cleaning blades of Examples 2 to 7 and Comparative Examples 1 to 3 were produced in the same manner as in Example 1.

[0160] In addition, the thickness of the above coating layer was controlled by the lifting speed during dipping. As the lifting speed increased, the thickness increased.

[0161] In addition, Comparative Example 1 was a cleaning blade having a blade base body without a coating layer provided thereon.

[0162] <Assembly of the image forming apparatus>

[0163] The cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3 were mounted on an intermediate transfer unit of a color multifunctional peripheral device (Imagio MPC4500, manufactured by Ricoh Company, Ltd.) (a configuration similar to that of the image forming apparatus 500 shown), and the image forming apparatus was assembled. In addition, the cleaning blade was mounted on the image forming apparatus such that the line pressure was 20 g / cm and the cleaning angle was 81°. Figure 5

[0164] <Measurement of the maximum indentation depth hmax of the indenter>

[0165] The maximum indentation depth hmax of the indenter of the above edge layer of the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3 was measured. As the measurement method of the above hmax, the measurement method described in the above item "Measurement of the maximum indentation depth hmax of the indenter" was adopted. The value of hmax shown in Table 1 represents the median value of the values measured at 4 to 6 points at each measurement position.

[0166] <Measurement of Martens hardness>

[0167] ​Measure the Martens hardness of the base layers of the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3. As the measurement method of the Martens hardness (HM), the measurement conditions are the same as those in the measurement of the "maximum penetration depth hmax of the indenter". The results are shown in Table 1. In addition, as the measurement position of the Martens hardness in the base layer, it is the position at a distance of 100 [μm] from the end of the base layer toward the inside. In addition, the Martens hardness represents the median value of the values measured at 4 to 6 points at each measurement position.

[0168] <Measurement of the average thickness in the coating layer>

[0169] Measure the average thickness of the coating layer in the cleaning blades obtained in Examples 1 to 7 and Comparative Examples 1 to 3. The results are shown in Table 1. As the measurement method of the average thickness, it can be measured by scraping off a part of the coating layer with a spatula or cotton swab, etc., and performing shape measurement using a contact surface roughness meter (Surftest SJ-500: manufactured by Mitutoyo).

[0170] <Evaluation of torque rise rate>

[0171] Use the above image forming apparatus to output under the following conditions, and measure the change rate of the driving torque rise of the intermediate transfer member. After the output, observe the front end of the cleaning blade with a laser microscope (LEXTOLS 4500, manufactured by Olympus Corporation), and evaluate the torque rise rate based on the following evaluation criteria. The evaluation results are shown in Table 1. In addition, "initial stage" in the evaluation criteria refers to the period from the output of the 1st sheet to the 500th sheet.

[0172] Environment: 23 °C / 45% RH

[0173] Paper passing condition: white paper chart

[0174] Number of output sheets: 5000 sheets (A4 size, horizontal)

[0175] -Evaluation criteria-

[0176] ◎: The change rate of torque rise is within 50% with respect to the initial stage, and there is no stop of the intermediate transfer member due to the driving torque rise. Further, when observing the front end of the cleaning blade after the output, there is no sign of warping at all.

[0177] ○: The change rate of torque rise is within 50% with respect to the initial stage, and there is no stop of the intermediate transfer member due to the driving torque rise. However, although there is a sign of warping when observing the front end of the cleaning blade after the output, since it is not at the level of toner leakage, there will be no problem in actual use.

[0178] ×: The intermediate transfer body stops due to an increase in torque, and when observing the front end of the cleaning blade after output, there are warping marks indicating the degree of toner leakage, which is a problem in actual use.

[0179] <Image quality evaluation (cleanliness)>

[0180] Using the above image forming apparatus, output is performed under the following conditions. Then, the front end of the cleaning blade and the surface of the intermediate transfer body are observed with a laser microscope (LEXTOLS4500, manufactured by Olympus Corporation), and evaluation is performed based on the following evaluation criteria. The evaluation results are shown in Table 1.

[0181] Environment: 27°C / 80% RH

[0182] Paper passing condition: Continuously output full solid images

[0183] Number of output sheets: 2000 sheets (A4 size, horizontal)

[0184] - Evaluation criteria -

[0185] ◎: Toner leaked due to poor cleaning cannot be visually confirmed on the printed paper or the intermediate transfer body, and even when observing the intermediate transfer body along the length direction with a microscope, toner streaks cannot be confirmed.

[0186] ○: Toner leaked due to poor cleaning cannot be visually confirmed on the printed paper or the intermediate transfer body, but when observing the intermediate transfer body along the length direction with a microscope, toner streaks can be confirmed.

[0187] ×: Toner leaked due to poor cleaning can be visually confirmed on both the printed paper and the intermediate transfer body.

[0188] Table 1

[0189]

[0190] As an embodiment of the present invention, for example, it is as described above.

[0191] (1) A cleaning blade that abuts against the surface of a component to be cleaned and removes residues on the surface of the component to be cleaned, characterized in that: the cleaning blade includes a cleaning blade base body having an elastic cleaning blade base body and a cleaning blade support member that supports the cleaning blade base body, the elastic cleaning blade base body has an edge layer and a coating layer provided on the leading edge ridge line portion that abuts against the image carrier, and the maximum penetration depth hmax of the indenter of a microhardness tester based on a nanoindentation hardness test at a position on the coating layer of the lower surface of the cleaning blade base body that is 100 [μm] away from the leading edge ridge line portion toward the inside is 4.0 [μm] or more and 10.0 [μm] or less.

[0192] (2) The cleaning blade according to (1) above, wherein: the maximum penetration depth hmax of the indenter of the micro-hardness tester based on the nano-indentation hardness test of the coating layer in the lower surface of the cleaning blade substrate is 5.5 [μm] or more and 7.5 [μm] or less.

[0193] (3) The cleaning blade according to (1) or (2) above, wherein: the thickness of the coating layer on the lower surface of the cleaning blade substrate is 0.5 μm or more and 10 μm or less at a position 100 μm away from the leading edge portion of the cleaning blade inward.

[0194] (4) The cleaning blade according to any one of (1) to (3) above, wherein: the coating layer is composed of particles and a resin, and the function of the resin is to be a bonding component between the particles and the elastic cleaning blade substrate.

[0195] (5) The cleaning blade according to any one of (1) to (4) above, wherein: the coating layer is a coating film composed of PTFE particles and a fluororesin, or a coating film composed of acrylic particles and a polyvinyl alcohol resin or a polyvinyl acetal resin.

[0196] (6) The cleaning blade according to any one of (1) to (5) above, wherein: the cleaning blade substrate is a single-layer structure of polyurethane rubber, or a laminated structure formed by laminating layers of polyurethane rubber with different Martens hardness.

[0197] (7) The cleaning blade according to (6) above, wherein: the cleaning blade substrate is a single-layer structure of polyurethane rubber, and the Martens hardness of the polyurethane rubber is 0.5 [N / mm 2 or more and 2 [N / mm 2 or less.

[0198] (8) A cleaning unit, characterized by comprising the cleaning blade according to any one of (1) to (7) above.

[0199] (9) An intermediate transfer unit, characterized by comprising an intermediate transfer body and the cleaning blade according to any one of (1) to (7) above.

[0200] (10) An image forming apparatus, characterized by comprising: a developing step of developing a latent image formed on an image carrier with toner, the image carrier having a latent image formed thereon and being capable of carrying a toner image; a primary transfer step of primarily transferring the toner image developed in the developing step onto an intermediate transfer member; and a secondary transfer step of transferring the toner image transferred onto the intermediate transfer member onto a recording medium, wherein the cleaning unit of the intermediate transfer member is the cleaning blade according to any one of the above (1) to (7).

Claims

1. A cleaning blade that abuts against the surface of a member to be cleaned and removes residues on the surface of the member to be cleaned, characterized in that: The cleaning blade includes a cleaning blade base body having an elastic cleaning blade base body and a cleaning blade support member that supports the cleaning blade base body. The elastic cleaning blade base body has an edge layer and a coating layer provided on a leading edge line portion that abuts against the image carrier. At a position on the coating layer of the lower surface of the cleaning blade base body that is 100 [μm] away from the leading edge line portion toward the inside, the maximum penetration depth hmax of the indenter of a microhardness tester based on a nanoindentation hardness test is 4.0 [μm] or more and 10.0 [μm] or less.

2. The cleaning blade according to claim 1, characterized in that: For the coating layer in the lower surface of the cleaning blade base body, the maximum penetration depth hmax of the indenter of the microhardness tester based on the nanoindentation hardness test is 5.5 [μm] or more and 7.5 [μm] or less.

3. The cleaning blade according to claim 1 or 2, characterized in that: The thickness of the coating layer on the lower surface of the cleaning blade base body is 0.5 μm or more and 10 μm or less at a position 100 μm away from the leading edge line portion of the cleaning blade toward the inside.

4. The cleaning blade according to claim 1 or 2, characterized in that: The coating layer is composed of particles and a resin, and the function of the resin is to serve as a bonding component between the particles and the elastic cleaning blade base body.

5. The cleaning blade according to claim 1 or 2, characterized in that: The coating layer is a coating film composed of PTFE particles and a fluororesin, or a coating film composed of acrylic particles and a polyvinyl alcohol resin or a polyvinyl acetal resin.

6. The cleaning blade according to claim 1 or 2, characterized in that: The cleaning blade base body is a single-layer structure of polyurethane rubber or a laminated structure formed by laminating multiple layers of polyurethane rubber with different Shore hardnesses.

7. The cleaning blade according to claim 6, characterized in that: The cleaning blade base is a single-layer structure of polyurethane rubber, and the Shore hardness of the polyurethane rubber is 0.5 [N / mm 2 or more and 2 [N / mm 2 or less.

8. A cleaning unit, characterized in that Including: The cleaning blade according to claim 1 or 2.

9. An intermediate transfer unit, characterized in that Including: An intermediate transfer member and the cleaning blade according to claim 1 or 2.

10. An image forming apparatus, characterized in that Including: A developing step of developing a latent image formed on an image carrier with toner, the image carrier having a latent image formed thereon and being capable of carrying a toner image; A primary transfer step of primarily transferring the toner image developed in the developing step to the intermediate transfer member, and A secondary transfer step of transferring the toner image transferred to the intermediate transfer member to a recording medium, The cleaning unit of the intermediate transfer member is the cleaning blade according to claim 1 or 2.

Images