Cleaning blade for intermediate transfer medium and image forming apparatus

Abstract

A cleaning blade for an intermediate transfer medium is provided. The cleaning target of the cleaning blade is the intermediate transfer medium. The cleaning blade includes an edge layer and a coating. The coating disposed on a forwardmost end of the edge layer, which contacts the intermediate transfer medium at the forwardmost end, contains a first fluorine-based resin and a second fluorine-based resin that is incompatible with the first fluorine-based resin. The cleaning blade for the intermediate transfer medium has a Martens hardness of 0.5 N / mm 2 or more and 3 N / mm 2 or less at a location that is 20 μm from a ridge line of the forwardmost end of the edge layer.

Description

Technical Field

[0001] This disclosure relates to a cleaning blade for intermediate transfer media and an image forming apparatus. Background Technology

[0002] To date, seamless tapes have been used as components of electrophotographic image forming equipment for various purposes. Recent full-color electrophotographic image forming equipment employs an intermediate transfer tape method, in which images developed in four colors (i.e., yellow, magenta, cyan, and black) are temporarily overlapped on an intermediate transfer tape and then transferred together onto a recording medium such as paper. Electrophotographic image forming equipment typically uses a cleaning blade as a cleaning unit configured to remove any residual toner adhering to the surface of the intermediate transfer tape. This cleaning blade includes: an elastic member formed, for example, of polyurethane rubber; and a support member.

[0003] The cleaning squeegee needs to be lubricated to suppress the increase in torque required for rotating, for example, the image carrier and the intermediate transfer medium, and to mitigate, for example, the friction between the cleaning squeegee and the intermediate transfer belt.

[0004] In recent years, to mitigate friction between the cleaning squeegee and the image carrier, a cleaning squeegee has been used that employs a lubricant containing a fluorine-based compound. The proposed cleaning squeegee uses vinylidene fluoride as the fluorine-based compound contained in the lubricant (see, for example, Japanese Unexamined Patent Application Publication No. 2000-147972, Japanese Unexamined Patent Application Publication No. 2004-101551, Japanese Patent No. 3278733, Japanese Unexamined Patent Application Publication No. 10-214009, and Japanese Unexamined Patent Application Publication No. 06-348193). To impart appropriate flexibility and hardness to the elastic member of the cleaning squeegee to minimize gouged wear at the leading edge ridge of the squeegee, the surface hardness (expressed as Marlowan hardness) of the proposed cleaning squeegee is set to 1.0 N / mm at a distance of 20 μm from the leading edge ridge of the elastic member. 2 Up to 15.0 N / mm 2 (For example, see Japanese Unexamined Patent Application Publication No. 2017-16083). Furthermore, to improve the sliding properties of the cleaning scraper, a dispersion obtained by dispersing polymethyl methacrylate (PMMA) particles in a fluorinated solvent is applied to the proposed cleaning scraper (for example, see Japanese Patent No. 2853598). Summary of the Invention

[0005] According to one embodiment, the cleaning blade for intermediate transfer media is a cleaning blade whose cleaning target is the intermediate transfer media. The cleaning blade for intermediate transfer media includes an edge layer and a coating. The coating disposed on the foremost edge of the edge layer comprises a first fluorinated resin (a fluorine-based resin) and a second fluorinated resin incompatible with the first fluorinated resin, the edge layer contacting the intermediate transfer media at the foremost edge. The cleaning blade for intermediate transfer media has a strength of 0.5 N / mm at a position 20 μm away from the ridge line at the foremost edge of the edge layer. 2 Or larger and 3N / mm 2 Or even lower Marsh hardness. Attached Figure Description

[0006] Other objects and further features of the invention will become clear from the following detailed description when read in conjunction with the accompanying drawings, wherein:

[0007] Figure 1 This is a schematic perspective view showing an example of a cleaning scraper of the present disclosure;

[0008] Figure 2 This is a schematic cross-sectional view showing another example of the cleaning scraper of this disclosure;

[0009] Figure 3 This is a schematic cross-sectional view showing an example of the shape of the foremost tip of the cleaning scraper of this disclosure;

[0010] Figure 4 This is a schematic cross-sectional view illustrating an example of the image forming apparatus of this disclosure; and

[0011] Figure 5 This is a schematic diagram illustrating an example of a method for forming a coating according to an embodiment of the present disclosure. Detailed Implementation

[0012] In the following description, embodiments of the invention will be described with reference to the accompanying drawings.

[0013] According to this disclosure, the object is to provide a cleaning blade for intermediate transfer media that can suppress the increase of torque even immediately after the start of use of the image forming apparatus and achieve good cleaning performance.

[0014] According to this disclosure, a cleaning blade for intermediate transfer media can be provided, which can suppress the increase of torque even immediately after the start of use of the image forming apparatus and achieve good cleaning performance.

[0015] The details of this disclosure will now be described.

[0016] (A cleaning scraper for intermediate transfer media)

[0017] The cleaning blade for intermediate transfer media disclosed herein is a cleaning blade whose cleaning target is the intermediate transfer media. The cleaning blade for intermediate transfer media includes an edge layer and a coating. The coating disposed on the foremost edge of the edge layer comprises a first fluoropolymer resin and a second fluoropolymer resin incompatible with the first fluoropolymer resin, the edge layer contacting the intermediate transfer media at the foremost edge. The cleaning blade for intermediate transfer media has a strength of 0.5 N / mm at a position 20 μm away from the ridge line of the foremost edge of the edge layer. 2 Or larger and 3N / mm 2 Or a lower martensitic hardness. The cleaning scraper can be further equipped with other components as needed.

[0018] The cleaning scraper for intermediate transfer media disclosed herein is configured to remove residues adhering to the intermediate transfer media by contacting the surface of the intermediate transfer media.

[0019] In this specification, the cleaning blade used for intermediate transfer media may be referred to as a "cleaning blade".

[0020] There are no particular restrictions on residues, as long as they adhere to the surface of the intermediate transfer medium and are removed by a cleaning squeegee. Examples of residues include toners, lubricants, inorganic particles, organic particles, paper dust, waste and dirt, and mixtures thereof.

[0021] For cleaning units using existing cleaning blades, the following problems exist: the friction generated when the cleaning blade and the intermediate transfer medium come into contact with each other increases the torque required to rotate the intermediate transfer medium and stops its rotation. There are also problems: friction wears down the portion of the cleaning blade that contacts the intermediate transfer medium, causing the cleaning blade to curl up or allowing toner to slide across it, resulting in poor cleaning performance.

[0022] To improve the sliding properties of the cleaning squeegee and suppress its curling and torque increase, a method of applying, for example, metallic soaps such as zinc stearate or polymethyl methacrylate (PMMA) particles as lubricants to the very tip of the cleaning squeegee (touch-up) is widely used. Typically, as the image forming apparatus is actuated, toner is gradually trapped between the cleaning squeegee and the intermediate transfer medium, and the trapped toner acts as a lubricant. Therefore, the lubricant only needs to exhibit lubricity for a short period from the actuation of the image forming apparatus to the stable behavior of the cleaning squeegee. However, a problem exists: the particles contained in existing lubricants have weak adhesion to the base material of the cleaning squeegee and detach from the cleaning squeegee before its behavior stabilizes.

[0023] As is well known, “suppressing torque increase” and “improving cleaning performance” are mutually exclusive trade-offs.

[0024] For example, when the portion of the cleaning blade in contact with the intermediate transfer medium is smoothed by applying, for example, a lubricant to suppress the increase in torque, toner slippage occurs, and cleaning performance deteriorates. When cleaning performance is improved by increasing friction by roughening the portion of the cleaning blade in contact with the intermediate transfer medium, torque increases.

[0025] Therefore, it is difficult to suppress the increase in torque while simultaneously improving cleaning performance.

[0026] As a result of careful research, the inventors have discovered that by applying a dispersion in which particles are dispersed in a mixture of solvent and binder components, rather than a dispersion in which particles are dispersed only in the solvent, to a cleaning squeegee to form a coating, particle detachment from the coating can be suppressed. The inventors have also discovered that by using a slidable fluoropolymer material as particles and a binder component, the squeegee roll-up and the increase in torque of the intermediate transfer medium can be suppressed.

[0027] The inventors also discovered that the martensitic hardness at a position 20 μm away from the foremost ridge of the edge layer is 0.5 N / mm. 2 Or larger and 3N / mm 2 Or even smaller, a sliding effect can be achieved without inhibiting the cleaning function.

[0028] Therefore, according to this disclosure, a cleaning blade for intermediate transfer media (whose cleaning target is the intermediate transfer media) is qualified as a cleaning blade capable of suppressing the increase of torque even immediately after the start of use of the image forming apparatus and exhibiting good cleaning performance, provided that the cleaning blade for intermediate transfer media comprises an edge layer and a coating, the coating disposed on the foremost tip of the edge layer (where the edge layer contacts the intermediate transfer media) comprises a first fluoropolymer resin and a second fluoropolymer resin incompatible with the first fluoropolymer resin, and the cleaning blade for intermediate transfer media has a strength of 0.5 N / mm at a position 20 μm away from the ridge line of the foremost tip of the edge layer. 2 Or larger and 3N / mm 2 Or even lower Marsh hardness.

[0029] <Coating>

[0030] The coating comprises a first fluoropolymer resin and a second fluoropolymer resin incompatible with the first fluoropolymer resin, and may further contain other components as needed.

[0031] The coating refers to a layer disposed on one end of the scraper base in the peripheral side surface of the scraper base described below, which serves as the foremost tip of the cleaning scraper.

[0032] The coating can be formed on at least a portion of the squeegee base, including the contact side of the squeegee base, which is the side where the cleaning squeegee and the intermediate transfer medium contact each other along their length. The coating can be formed entirely along the contact side and can be formed on all surfaces of the squeegee base. Of these options, it is preferred that the coating be formed entirely along the contact side.

[0033] The surface area of ​​the scraper base without a coating can be called the "uncoated area".

[0034] In this disclosure, "incompatibility" refers to the property that a mixture of multiple substances does not completely imming with each other due to the existence of interfaces between the substances. "Compatibility" refers to the property that a mixture of multiple substances can mix together without interfaces between the substances.

[0035] In this disclosure, "incompatible state" is a state in which there is an interface between the first fluoropolymer and the second fluoropolymer, and may be a state in which the fluoropolymer and the second fluoropolymer are partially compatible.

[0036] In one form of incompatibility, it is preferred that the coating has an island structure.

[0037] The island structure refers to a structure in which one component contained in the coating formed on the cleaning scraper exists in the shape of an "island" (hereinafter referred to as a domain) in the "sea", while the continuous layer formed by another component contained in the coating is referred to as a "sea" (hereinafter referred to as a matrix).

[0038] The island structure disclosed herein represents a state in which the first fluoropolymer constituting the domain and the second fluoropolymer constituting the matrix are incompatible and there is no compatible portion.

[0039] When the coating has an island structure, it is preferable that the domain of the island structure is a particle.

[0040] The average thickness of the coating on the cleaning scraper is preferably 2 μm or greater and 10 μm or less.

[0041] Sufficient sliding effect can be obtained when the average coating thickness is 2 μm or greater. Coating detachment can be suppressed when the average coating thickness is 10 μm or less.

[0042] The average thickness of the coating can be obtained by averaging the thickness measurements (μm) obtained at three or more locations on the coating.

[0043] There are no particular restrictions on the location where the average thickness of the coating is measured. Examples of such locations include a distance of 20 μm from either of any pair of opposite ends of the coating, and the center of the coating between any pair of opposite ends.

[0044] The average thickness of the coating can be measured by scraping a portion of the coating with, for example, a spatula or cotton swab, and then using a three-dimensional measuring instrument such as a contact surface roughness tester (SURFTEST SJ-500: available from Mitutoyo Corporation) or a laser microscope (LEXT OLS4100: available from Olympus Corporation) to measure the profile of the scraped portion.

[0045] One embodiment and another embodiment of the cleaning squeegee of this disclosure will be described with reference to the accompanying drawings. The uses of the cleaning squeegee of this disclosure are not limited to these embodiments.

[0046] The same reference numerals are used to denote the same parts in the accompanying drawings, and any redundant descriptions of the same parts may be omitted. For example, the number, location, and shape of the parts are not limited to those in the embodiments, and may be any number, location, and shape suitable for carrying out this disclosure.

[0047] Figure 1 This includes a schematic perspective view illustrating one embodiment of the cleaning squeegee of this disclosure, as well as an enlarged view of the contact portion and its surrounding portion. The cleaning squeegee 62 is formed of: a flat cleaning squeegee support member 621 made of a rigid material such as metal or hard plastic; and a flat cleaning squeegee base 622, one end of which is connected to the cleaning squeegee support member 621 and has a free end of a predetermined length at the opposite end. The cleaning squeegee base 622 is fixed to one end of the cleaning squeegee support member 621 by, for example, an adhesive, and the other end of the cleaning squeegee support member 621 is suspended from the cleaning device housing. The cleaning squeegee base 622 has a frontal cleaning squeegee facet 62a, a lower cleaning squeegee surface 62b, a cleaning squeegee contact portion 62c (which is one end of the cleaning squeegee 622 on the free end side), and a cleaning squeegee side surface 62d, and has a coating 623 on at least a portion of the cleaning squeegee base 622, said portion including the contact side of the cleaning squeegee contact portion 62c.

[0048] The cleaning squeegee 62 has a cleaning squeegee contact portion 62c that contacts the surface of the intermediate transfer medium along the longer dimension of the cleaning squeegee 62.

[0049] Figure 2This is a schematic cross-sectional view illustrating another embodiment of the cleaning squeegee of this disclosure. The cleaning squeegee 62 is formed from a cleaning squeegee support member 621 and a cleaning squeegee base 622. The cleaning squeegee base 622 has an edge layer 622a and a base layer 622b, both of which are resilient, a contact portion 62c, and a coating 623 on at least a portion of the cleaning squeegee base 622, said portion including the contact side of the contact portion 62c. Figure 2 The frontmost surface 62a, the lower surface 62b, and the side surface 62d of the cleaning scraper are not shown.

[0050] <<First Fluoropolymer Resin>>

[0051] The fluorinated resins disclosed herein refer to resins containing fluorine in their molecules. As fluorinated resins, fluorinated olefin polymers are preferred, and olefin polymers in which hydrogen atoms are replaced by fluorine atoms are more preferred.

[0052] According to one aspect of this disclosure, it is preferred that the first fluoropolymer is a domain of the island structure of the coating.

[0053] Preferably, the type and amount of the first fluoropolymer resin are selected relative to the type and amount of the second fluoropolymer resin described below, with the first fluoropolymer resin being the domain.

[0054] The shape of the field is not particularly limited and can be appropriately selected according to the intended purpose, and can be regular or irregular. Among these shapes, regular shapes are preferred.

[0055] When the shape of the domain is a regular shape, a sphere is preferred.

[0056] When the shape of the domain is spherical, the particle shape is preferred.

[0057] This shape is preferred because it minimizes problems such as damage to the intermediate transfer medium or the base of the cleaning squeegee caused by fluoropolymer that may detach from the coating.

[0058] The volume average particle size (50% volume basis diameter, median diameter) of the first fluoropolymer is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 0.1 μm or larger and 1 μm or smaller, more preferably 0.5 μm or smaller, and even more preferably 0.3 μm or smaller. When the volume average particle size of the first fluoropolymer is 1 μm or smaller, the disadvantages of the first fluoropolymer having an increased tendency to precipitate in the solvent and a decreased tendency to be stably dispersed in the solvent can be minimized. When the volume average particle size of the first fluoropolymer is 0.5 μm or smaller, the first fluoropolymer can be more stably dispersed in non-aqueous solvents.

[0059] There are no particular limitations on the methods for measuring volume-average particle size (50% volume basis diameter, median diameter), and they can be appropriately selected according to the intended purpose. Volume-average particle size can be measured by, for example, laser diffraction / scattering methods, dynamic light scattering methods, and imaging methods.

[0060] Specific examples of methods for measuring volume average particle size include methods for measuring the volume average particle size of particles collected from the coating of a cleaning blade using laser diffraction / scattering methods with MICROTRAC (available from Nikkiso Co., Ltd.), and methods for measuring volume average particle size by directly observing particles on the cleaning blade using scanning electron microscopy (SEM).

[0061] There is almost no difference in volume average particle size between the particles added to the dispersion to be applied to the cleaning scraper and the particles present in the coating.

[0062] The content of the first fluoropolymer in the coating is not particularly limited and can be appropriately selected according to the intended purpose. Because a sliding effect can be obtained, it is preferably 4% by mass or more and 8% by mass or less relative to the total mass of the coating, more preferably 4.5% by mass or more and 5.5% by mass or less. The sliding effect obtainable by the first fluoropolymer in the coating is maximized when the content of the first fluoropolymer in the coating is 8% by mass relative to the total mass of the coating. Sufficient sliding effect can be obtained when the content of the first fluoropolymer in the coating is 4% by mass or more relative to the total mass of the coating.

[0063] There are no particular limitations on the first fluoropolymer resin, and it can be appropriately selected according to the intended purpose. Examples of first fluoropolymer resins include polytetrafluoroethylene (PTFE), fluoroethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), trifluorochloroethylene copolymer (CTFE), tetrafluoroethylene-trifluorochloroethylene copolymer (TFE / CTFE), ethylene-trifluorochloroethylene copolymer (ECTFE), and polytrifluorochloroethylene (PCTFE). Among these resins, polytetrafluoroethylene (PTFE) is preferred for better improving the gliding properties of the cleaning scraper.

[0064] Polytetrafluoroethylene (PTFE) can be a properly synthesized product or a commercially available product.

[0065] Examples of commercially available polytetrafluoroethylene (PTFE) products include DYNEON TF ultrafine powder TF-9201Z and DYNEON TF ultrafine powder TF-9207Z (both available from 3M Japan Co., Ltd.), NANO FLON119N and FLUORO E (both available from Nippon Dacro Shamroc Co., Ltd.), TLP10F-1 (available from Chemours-Mitsui Fluoroproducts Co., Ltd.), KTL-500F (available from Kitamura Limited), and ALGOFLON L203F (available from SOLVAY).

[0066] <<Second Fluoropolymer Resin>>

[0067] In this disclosure, when the coating comprises a second fluoropolymer, the adhesion of the first fluoropolymer to the cleaning scraper substrate is improved, and coating detachment can be suppressed. Therefore, scraping or increased torque of the cleaning scraper can be suppressed.

[0068] According to one aspect of this disclosure, it is preferred that the second fluorinated resin is the matrix of the island structure of the coating.

[0069] Preferably, the second fluoropolymer resin is used as the matrix, and the type and amount of the second fluoropolymer resin are selected relative to the type and amount of the first fluoropolymer resin.

[0070] There are no particular limitations on the second fluorinated resin, and it can be appropriately selected according to the intended purpose, provided that the first fluorinated resin can be uniformly and stably dispersed in the second fluorinated resin. Examples of second fluorinated resins include vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE). Among these resins, copolymers combining these resins are preferred in terms of imparting lubricity and adhesion to the scraper base, and VdF-HFP-TFE terpolymers are more preferred.

[0071] When assuming they are in their respective monomeric forms, the composition ratio of VdF:HFP:TFE in the terpolymer is preferably 30 mol% to 80 mol%: 10 mol% to 35 mol%: 5 mol% to 35 mol%.

[0072] As a second fluorinated resin, a mixture of a second fluorinated resin and a fluorinated oil can be used.

[0073] Mixing with fluorinated oils can further improve the sliding function, not just the adhesive function.

[0074] Examples of fluorinated oils include tetrafluoroethylene (TFE) oligomers and fluorinated oils containing perfluoroethers in the main structure.

[0075] When a mixture of a second fluoropolymer and a fluoropolymer oil is used as the second fluoropolymer, in order to suppress contamination of intermediate transfer media, for example, due to the exudation of the fluoropolymer oil, the content of the second fluoropolymer relative to the total mass of the mixture is preferably 90% by mass or more and 99% by mass or less, and more preferably 95% by mass or more and 98% by mass or less.

[0076] There are no particular limitations on fluoropolymer oils containing perfluoroethers in the main matrix, and they can be appropriately selected according to the intended purpose, as long as the fluoropolymer oil has sliding properties and does not interfere with the dispersion of the fluoropolymer resin. In terms of kinematic viscosity, the average molecular weight of the fluoropolymer oil is preferably between 2000 and 3500.

[0077] The same or different materials can be used for the first and second fluoropolymers disclosed herein. When using the same materials, a coating can be produced by employing ingenuity in the production method, making the first and second fluoropolymers incompatible with each other. For example, by adding the second fluoropolymer to a previously cured first fluoropolymer and then curing them, a coating in which an interface is formed between the first and second fluoropolymers and the fluoropolymers are partially incompatible with each other can be produced. A coating can also be produced by mixing a first fluoropolymer with hydrophilic substituents with a second fluoropolymer with hydrophobic substituents.

[0078] <<Any other component (A)>>

[0079] There are no particular limitations on any other component (A), and it may be appropriately selected according to the intended purpose. Examples of any other component (A) include particles other than fluoropolymer particles.

[0080] There are no particular restrictions on particles other than fluoropolymer particles, and they can be appropriately selected according to the intended purpose. Examples of particles other than fluoropolymer particles include inorganic compound particles, acrylic resins, styrene resins, and vinyl resins.

[0081] Examples of inorganic compound particles include silicon dioxide, aluminum oxide, and zirconium oxide.

[0082] One of these types of particles can be used alone, or two or more of these types of particles can be used in combination.

[0083] The shape of particles other than fluoropolymer particles is not particularly limited and can be appropriately selected according to the intended purpose, but spherical shape is preferred. Spherical shape is preferred because particles other than fluoropolymer particles with spherical shape can suppress problems such as damage to the intermediate transfer medium or the base of the cleaning squeegee when the particles detach from the coating.

[0084] The volume average particle size (50% volume basis diameter, median diameter) of particles other than fluoropolymer particles is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 0.1 μm or larger and 1 μm or smaller, more preferably 0.5 μm or smaller, and even more preferably 0.3 μm or smaller. When the volume average particle size of particles other than fluoropolymer particles is 1 μm or smaller, the disadvantages of particles other than fluoropolymer particles having an increased tendency to precipitate in solvents and a decreased tendency to be stably dispersed in solvents can be minimized. When the volume average particle size of particles other than fluoropolymer particles is 0.5 μm or smaller, particles other than fluoropolymer particles can be more stably dispersed in non-aqueous solvents.

[0085] There are no particular limitations on the methods for measuring volume-average particle size (50% volume basis diameter, median diameter), and they can be appropriately selected according to the intended purpose. Volume-average particle size can be measured by, for example, laser diffraction / scattering methods, dynamic light scattering methods, and imaging methods.

[0086] Specific examples of methods for measuring volume average particle size include methods for measuring the volume average particle size of particles collected from the coating of a cleaning blade using laser diffraction / scattering methods with MICROTRAC (available from Nikkiso Co., Ltd.), and methods for measuring volume average particle size by directly observing particles on the cleaning blade using scanning electron microscopy (SEM).

[0087] There are no particular limitations on the method for preparing the coating, and it can be appropriately selected according to the intended purpose. For example, the coating can be obtained by adding and mixing a mixture of a first fluoropolymer resin with a solvent and a second fluoropolymer resin (a second fluoropolymer resin dispersion), and applying the resulting particulate dispersion to the base of a cleaning scraper.

[0088] There are no particular restrictions on the solvent, and it can be appropriately selected according to the intended purpose. Examples of solvents include fluorinated organic solvents.

[0089] Examples of fluorinated organic solvents include hydrofluoroethers (HFE), perfluorocarbons (PFC), and perfluoroethers (PFE).

[0090] One of these solvents can be used alone, or two or more of these solvents can be used in combination.

[0091] In this disclosure, since a uniform dispersion can be obtained, the average particle size of the particles contained in the second fluoropolymer dispersion, as measured by the dynamic light scattering method (i.e., the average particle size obtained from the scattering intensity distribution by the cumulative amount method), is preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.3 μm or less.

[0092] Typically, even when using particles with a volume average particle size of 1 μm or smaller, these particles will flocculate and form secondary particles, becoming particles with a volume average particle size of 1 μm or larger (secondary particles). By dispersing the flocculated particles that form secondary particles in a manner with a particle size of 1 μm or smaller, the viscosity of the second fluoropolymer dispersion can be reduced, and a dispersion that remains stable during long-term storage can be obtained.

[0093] There are no particular limitations on the dispersion method, and it can be appropriately selected according to the intended purpose. Examples of this method include methods using dispersers, such as ultrasonic dispersers, three-roll mills, ball mills, bead mills, and jet mills.

[0094] There are no particular limitations on the methods for forming the coating, and they can be appropriately selected according to the intended purpose. Examples of such methods include an impregnation process in which the entire or part of the base of a cleaning scraper is immersed in and treated with the particulate dispersion. In addition to impregnation, coating methods such as spraying and dispensing can also be used.

[0095] <Scraper base>

[0096] In this specification, the base of the cleaning scraper may be referred to as the "scraper base" or "base".

[0097] The shape of the squeegee base can be appropriately selected according to the intended purpose, as long as the squeegee base has a structure capable of removing residues from the intermediate transfer medium. Preferably, the contact side of the contact portion of the squeegee base (where the squeegee base contacts the intermediate transfer medium) is a straight line. Examples of squeegee base shapes include a plate shape.

[0098] There are no particular limitations on the structure of the scraper base, and it can be appropriately selected according to the intended purpose. Examples of scraper base structures include single-layer structures, laminated structures, and laminated structures in which multiple components are combined. Among these structures, single-layer structures and laminated structures in which multiple components are laminated are preferred because these structures are easy to manufacture into cleaning scrapers.

[0099] When the scraper base has a laminated structure, the layer in contact with the intermediate transfer medium can be called the edge layer, and the layer that is not the edge layer can be called the base layer. When the scraper base consists of a single layer, the scraper base only includes the edge layer.

[0100] Preferably, the martensitic hardness of the multiple components in the laminated structure is different.

[0101] There are no particular restrictions on the material of the squeegee base, and it can be appropriately selected according to the intended purpose. For minimizing wear on the squeegee base and ensuring adequate removal of residues from the intermediate transfer medium, an elastic material with suitable elasticity and hardness is preferred.

[0102] There are no particular limitations on the elastic material, and it can be appropriately selected according to the intended purpose, as long as the elastic material has high elasticity. Examples of elastic materials include polyurethane rubber, silicone rubber, fluororubber, nitrile rubber (NBR), and ethylene propylene diene rubber (EPDM). Among these elastic materials, polyurethane rubber is preferred in terms of durability and stain resistance.

[0103] There are no particular restrictions on the size of the squeegee base, and it can be appropriately selected according to the size of the intermediate transfer medium.

[0104] The martensitic hardness of the polyurethane rubber in the cleaning scraper disclosed herein is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 0.5 N / mm. 2 Or larger and 2N / mm 2 Or even less. When the Martens hardness of the polyurethane rubber in the cleaning blade is within the preferred range, problems such as poor cleaning performance caused by the inability to obtain linear load on the blade and the tendency for the contact area of ​​the contact portion to contact the intermediate transfer medium to increase, and the possibility of the cleaning blade cracking when the base of the blade is too hard, can be overcome.

[0105] There are no particular limitations on the method for producing the scraper base, and it can be appropriately selected according to the intended purpose. For example, the scraper base can be obtained by preparing a polyurethane prepolymer using polyol compounds and polyisocyanate compounds, adding a curing agent and a curing catalyst to the polyurethane prepolymer as needed, centrifugally casting the polyurethane prepolymer in a predetermined mold, aging (curing) the resulting product at room temperature, and cutting the resulting product into a plate shape with a predetermined size.

[0106] There are no particular limitations on polyol compounds, and they can be appropriately selected according to the intended purpose. Examples of polyol compounds include high molecular weight polyols and low molecular weight polyols.

[0107] Examples of high molecular weight polyols include: polyester polyols, which are condensations of alkylene glycols and aliphatic diacids; polyester polyols, such as polyester polyols between alkylene glycols and adipic acid, such as ethylene glycol adipate polyols, butylene adipate polyols, ethylene glycol adipate propylene glycol adipate polyols, ethylene glycol adipate butylene glycol adipate polyols and ethylene glycol adipate neopentyl glycol adipate polyols; polycaprolactone-based polyols, such as polycaprolactone polyols obtained by ring-opening polymerization of caprolactone; and polyether-based polyols, such as poly(oxytetramethylene) glycol and poly(propylene oxide) glycol.

[0108] One of these high molecular weight polyols can be used alone, or two or more of these high molecular weight polyols can be used in combination.

[0109] Examples of low molecular weight polyols include: divalent alcohols, 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 trivalent or more valent alcohols, such as 1,1,1-trimethylolpropane, glycerol, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, 1,1,1-tris(hydroxyethoxymethyl)propane, diglycerol, and pentaerythritol.

[0110] One of these low molecular weight polyols can be used alone, or two or more of these low molecular weight polyols can be used in combination.

[0111] There are no particular limitations on the polyisocyanate compounds, and they can be appropriately selected according to the intended purpose. Examples of polyisocyanate compounds include methylene diphenyl diisocyanate (MDI), methyl phenyl diisocyanate (TDI), xylene diisocyanate (XDI), naphthylene 1,5-diisocyanate (NDI), tetramethylxylene diisocyanate, isophorone diisocyanate (IPDI), hydrogenated xylene diisocyanate H6XDI, dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), and trimethylhexamethylene diisocyanate (TMDI).

[0112] One of these polyisocyanate compounds can be used alone, or two or more of these polyisocyanate compounds can be used in combination.

[0113] There are no particular limitations on curing agents, and they can be appropriately selected according to the intended purpose. Examples of curing agents include amines and alcohols.

[0114] One of these curing agents can be used alone, or two or more of these curing agents can be used in combination.

[0115] For example, hardeners are used to adjust the hardness of the scraper base.

[0116] There are no particular limitations on the curing catalyst, and it can be appropriately selected according to the intended purpose. Examples of curing catalysts include 2-methylimidazole and 1,2-dimethylimidazole.

[0117] There is no particular limitation on the content of the curing catalyst, which can be appropriately selected according to the intended purpose, and is preferably 0.01% by mass or more and 0.5% by mass or less relative to the total mass of the prepolymer and curing agent, more preferably 0.05% by mass or more and 0.3% by mass or less.

[0118] According to JIS K6255, the modulus of resilience of the scraper base is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 10% to 80% at 23°C.

[0119] When the modulus of resilience is within the preferred range, problems such as poor cleaning performance caused by failure of the following scraper base (which is inflexible outside the preferred range) or roughness of the intermediate transfer medium can be overcome, as well as scraper noise that may occur when the scraper base rebounds too strongly.

[0120] For example, according to the JIS K6255 standard, the elastic modulus of the scraper base can be measured at 23°C using a rebound tester No. 221, which is available from Toyo Seiki Seisaku-sho, Ltd.

[0121] <Madall hardness>

[0122] When the cleaning scraper of this disclosure has a strength of 0.5 N / mm at a distance of 20 μm from the foremost ridge of the edge layer... 2 Or larger and 3N / mm 2 Sufficient sliding effect can be obtained when the martensitic hardness is lower or even lower.

[0123] Because it achieves good sliding performance, the martensitic hardness of the cleaning scraper disclosed herein is preferably 1.0 N / mm² at a distance of 20 μm from the foremost ridge of the edge layer. 2 Or larger and 2.6 N / mm 2 Or smaller.

[0124] The preferred martensitic hardness of the cleaning scraper is 0.5 N / mm at a distance of 20 μm from the foremost ridge of the edge layer. 2 Advantageously, when the pressure is greater, the problem of not achieving the desired sliding effect due to insufficient adhesion of the first and second fluoropolymer particles to the edge layer can be overcome. When the distance from the foremost ridge of the edge layer is 20 μm, the martensitic hardness of the cleaning scraper is preferably 3 N / mm. 2 When the size is smaller, it is advantageous to overcome the problem that the first and second fluoropolymer particles adhere excessively to the edge layer and interfere with the cleaning function.

[0125] In this disclosure, the martensitic hardness is measured from a product processed into a cleaning scraper.

[0126] There are no particular limitations on the method for measuring martensitic hardness (HM), and it can be appropriately selected according to the intended purpose. For example, according to ISO 14577, a nano-indenter (ENT-3100, available from Elionix Inc.) can be used to measure martensitic hardness by pressing the Berkowitz indenter into the measuring position for 10 seconds under a load of 1,000 μN, holding the Berkowitz indenter in this position for 5 seconds, and removing the Berkowitz indenter within 10 seconds under the same load rate.

[0127] There are no particular restrictions on the location of the base layer where the martensitic hardness is measured, and because it is easy to measure, it can be located at a position 20 μm from one end of the base layer.

[0128] Martens hardness is the average of measurements obtained at 4 to 6 points at each measurement location.

[0129] Intermediate transfer medium

[0130] Intermediate transfer media may contain resin and resistance regulator, and may contain any other components as required (B).

[0131] There are no particular limitations on intermediate transfer media, and they can be appropriately selected according to the intended purpose, as long as the toner image obtained by developing the latent image formed on the image carrier can be transferred onto the intermediate transfer media. Examples of intermediate transfer media include intermediate transfer belts and secondary transfer belts.

[0132] -Resin-

[0133] There are no particular limitations on the resins contained in the intermediate transfer medium, and they can be appropriately selected according to the intended purpose. Examples of resins include fluorinated resins such as polyvinylidene fluoride (PVDF) and ethylene tetrafluoroethylene (ETFE), polyimide resins, and polyamide-imide resins. Among these resins, polyimide resins and polyamide-imide resins are preferred in terms of mechanical strength (high elasticity) and heat resistance.

[0134] There are no particular limitations on polyamide resins and polyamide-imide resins, and they can be appropriately selected according to the intended purpose. For example, general commercial resins available from manufacturers such as Du Pont-Toray Co., Ltd., Ube Corporation, NewJapan Chemical Co., Ltd., JSR Corporation, Unitika Ltd., IST Corporation, Hitachi Kasei Kogyo KK, Toyobo Co., Ltd., and Arakawa Kagaku Kabushiki Kaisha can be used.

[0135] -Resistance regulator-

[0136] There are no particular limitations on resistance regulators, and they can be appropriately selected according to the intended purpose. Examples of resistance regulators include metal oxides, carbon black, ionic conductive agents, and conductive polymers.

[0137] There are no particular limitations on the metal oxides used, and they can be appropriately selected depending on the intended purpose. Examples of metal oxides include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. For better dispersibility, surface treatment can be applied to the metal oxides beforehand.

[0138] There are no particular restrictions on carbon black, and it can be selected appropriately according to the intended purpose. Examples of carbon black include Ketjen black, furnace black, acetylene black, thermal black, and gas black.

[0139] There are no particular limitations on ionic conductive agents, and they can be appropriately selected according to the intended purpose. Examples of ionic conductive agents include tetraalkylammonium salts, trialkylbenzylammonium salts, alkyl sulfonates, alkylbenzene sulfonates, alkyl sulfates, glycerol fatty acid esters, dehydrated sorbitol fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty alcohol esters, alkyl betaine, and lithium perchlorate.

[0140] Examples of conductive polymers include poly(p-phenylene), polyaniline, polythiophene, and poly(p-phenylenevinylene).

[0141] One of these resistance regulators can be used alone, or two or more of these resistance regulators can be used in combination.

[0142] The content of the resistance regulator in the intermediate transfer medium is not particularly limited and can be appropriately selected according to the intended purpose. When the resistance regulator is carbon black, the content of the resistance regulator relative to the total mass of the intermediate transfer medium 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. When the resistance regulator is a metal oxide, the content of the resistance regulator relative to the total mass of the intermediate transfer medium 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. When the content of the resistance regulator is greater than or equal to the lower limit of the preferred range, the problem of not being able to obtain the resistance regulation effect can be overcome. When the content of the resistance regulator is less than or equal to the upper limit of the preferred range, the intermediate transfer belt can obtain good mechanical strength.

[0143] -Any other component (B)-

[0144] There are no particular limitations on any other component (B), and it may be appropriately selected according to the intended purpose. Examples of any other component (B) include dispersants, reinforcing agents, lubricants, heat transfer agents, and antioxidants.

[0145] The average thickness of the intermediate transfer medium is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 30 μm or greater and 150 μm or less, more preferably 40 μm or greater and 120 μm or less, and particularly preferably 50 μm or greater and 80 μm or less. When the average thickness of the intermediate transfer medium is 30 μm or greater and 150 μm or less, there is an advantage that the intermediate transfer belt has improved durability. Preferably, for higher operational stability, the intermediate transfer medium has the smallest possible thickness non-uniformity.

[0146] There are no particular limitations on the methods used to measure the average thickness of the intermediate transfer medium, and they can be appropriately selected depending on the intended purpose. Examples of such methods include measurements using contact or eddy current film thickness gauges, and measurements of the film's cross-section using scanning electron microscopy (SEM).

[0147] <Other Components>

[0148] Other components are not particularly restricted and can be appropriately selected according to the intended purpose. Examples of other components include support components.

[0149] <<Supporting Components>>

[0150] There are no particular restrictions on the shape of the support member, and it can be appropriately selected according to the intended purpose. Examples of support member shapes include plate shapes.

[0151] There are no particular restrictions on the structure of the supporting components, and they can be appropriately selected according to the intended purpose.

[0152] There are no particular restrictions on the size of the support components, and they can be appropriately selected according to the size of the intermediate transfer medium.

[0153] There are no particular limitations on the material of the support components, and they can be appropriately selected according to the intended purpose. Examples of materials for support components include metals, plastics, and ceramics. Among these materials, metals are preferred in terms of strength, and steels such as stainless steel, aluminum, and phosphor bronze are more preferred.

[0154] (Image forming apparatus and image forming method)

[0155] The image forming apparatus disclosed herein includes a developing unit, a primary transfer unit, a secondary transfer unit, and a cleaning unit, and may further include other units as needed.

[0156] The cleaning unit includes the cleaning scraper for intermediate transfer media disclosed herein.

[0157] The image forming method related to this disclosure includes a developing step, a primary transfer step, a secondary transfer step, and a cleaning step, and may further include other steps as needed.

[0158] The cleaning steps are performed using the cleaning scraper for intermediate transfer media disclosed herein.

[0159] The image forming method related to this disclosure can be appropriately performed by the image forming apparatus of this disclosure. The developing step can be performed by a developing unit. The primary transfer step can be performed by a primary transfer unit. The secondary transfer step can be performed by a secondary transfer unit. The cleaning step can be performed by a cleaning unit. Other steps can be performed by other units.

[0160] <Developing Steps and Developing Units>

[0161] The developing step is a step of developing a latent image formed on an image carrier capable of carrying the toner image using a toner, and is performed by the developing unit.

[0162] There are no particular limitations on the developing unit, and it can be appropriately selected according to the intended purpose, as long as the developing unit can develop the latent image into a toner image. Examples of developing units include developing units that at least include a developing apparatus containing toner and capable of applying the toner to the latent image in a contact or non-contact manner.

[0163] The developing apparatus can be of the dry developing type or the wet developing type, or a single-color developing apparatus or a multi-color developing apparatus. Examples of developing apparatuses include those comprising: a stirring device configured to apply friction and stir the toner to charge the toner; and a rotatable magnetic roller.

[0164] For example, in a developing apparatus, toner is stirred and mixed with a carrier as needed, charged by the friction of stirring, and carried in a chain-like manner on the surface of a rotating magnetic roller to form a magnetic brush.

[0165] The magnetic roller is positioned near the image carrier. Therefore, the toner constituting the magnetic brush formed on the surface of the magnetic roller is partially transferred to the surface of the image carrier by the electrostatic attraction of the latent image. As a result, the latent image is developed using the toner, and a toner image is formed on the surface of the image carrier.

[0166] The toner contained in the developing apparatus may be a developing agent containing a toner. The developing agent may be a single-component developing agent or a two-component developing agent.

[0167] Toners can also be used as carrier-free, single-component magnetic or non-magnetic toners.

[0168] <One-step transfer process and one-step transfer unit, and two-step transfer process and two-step transfer unit>

[0169] A single transfer step is a process in which the toner image developed in the developing step is transferred to an intermediate transfer medium in one step, and is performed by a single transfer unit.

[0170] The secondary transfer step is the process of transferring the toner image transferred to the intermediate transfer medium onto the recording medium, and is performed by the secondary transfer unit.

[0171] As a primary transfer unit and a secondary transfer unit, for example, a unit that includes at least a transfer device is preferred, which is configured to charge the toner formed on the surface of the image carrier in such a manner as toner images are stripped onto the recording medium.

[0172] There are no particular limitations on the transfer apparatus, and it can be appropriately selected according to the intended purpose. Examples of transfer apparatus include corona transfer apparatus using corona discharge, transfer belts, transfer rollers, pressure transfer rollers, and adhesive transfer apparatus. One, two, or more transfer apparatuses may be used.

[0173] There are no particular limitations on the recording medium, and it can be appropriately selected according to the intended purpose, as long as the toner image, which has not yet been fixed after development, can be transferred onto the recording medium. A representative example of a recording medium is plain paper. However, polyethylene terephthalate (PET) substrates for overhead projection (OHP) can also be used, for example.

[0174] <Cleaning Steps and Cleaning Units>

[0175] The cleaning step is the process of removing toner residues from the surface of the intermediate transfer medium, and it is performed by the cleaning unit.

[0176] As a cleaning unit, a cleaning unit in which the cleaning scraper of the present disclosure is fixed to a support member.

[0177] The linear load applied by the base of the cleaning squeegee of this disclosure to the surface of the intermediate transfer medium is not particularly limited and can be appropriately selected according to the intended purpose, and is preferably 10 N / m or higher and 100 N / m or lower, more preferably 10 N / m or higher and 50 N / m or lower. When the linear load is 10 N / m or higher and 100 N / m or lower, poor cleaning performance due to the toner sliding between the contact portion of the cleaning squeegee and the intermediate transfer medium is less likely to occur, and it is more likely to suppress the curling of the squeegee base.

[0178] Linear loads can be measured using a measuring instrument that includes a small, compressive load cell available from Kyowa Dengyo Co., Ltd.

[0179] The angle formed between the tangent of the intermediate transfer medium and the frontmost face of the cleaning blade at the free end of the contact portion of the cleaning blade (e.g., Figure 3 (As shown) There are no particular limitations, and the angle can be appropriately selected according to the intended purpose, and is preferably 65° or greater and 85° or less. This angle is referred to below as the "cleaning angle".

[0180] When the cleaning angle is 65° or greater and 85° or smaller, there is an advantage that the scraper base can be more reliably suppressed and poor cleaning performance can be reduced.

[0181] <Other steps and other units>

[0182] Examples of other steps include charging, exposure, fixing, charge removal, recovery, and control steps.

[0183] The charging and exposure steps can be collectively referred to as the electrostatic latent image formation steps.

[0184] Examples of other units include a charging unit, an exposure unit, a fixing unit, a charge removal unit, a recovery unit, and a control unit.

[0185] The charging unit and the exposure unit can be collectively referred to as the electrostatic latent image forming unit.

[0186] -Charging steps and charging unit-

[0187] The charging step is a step of charging the surface of the image carrier, and is performed by the charging unit.

[0188] There are no particular limitations on the charging unit, and it can be appropriately selected according to the intended purpose, as long as the charging unit can charge the surface of the image carrier. Examples of charging units include known contact chargers (including, for example, conductive or semi-conductive rollers, brushes, films, or rubber scrapers) and contactless chargers that utilize corona discharge (such as corona tube chargers and scorotron chargers).

[0189] The charging unit can take any form, such as a roller, magnetic brush, or bristle brush. The form of the charging unit can be selected based on the specifications and form of the electrophotographic image forming equipment.

[0190] When a magnetic brush is used as a charging unit, it uses various types of ferrite particles (such as Zn-Cu ferrite) as the charging medium. The magnetic brush consists of a non-magnetic conductive sleeve on which the charging medium is supported and a magnetic roller encapsulated within the conductive sleeve.

[0191] When the brush is used as a charging unit, the material used for the brush is fur treated with, for example, carbon, copper sulfide, metal, or metal oxide to make it conductive. The treated fur is wrapped around or attached to a metal or any other conductive core rod and can be used as a charger.

[0192] The charger is not limited to the contact charger described above. However, a contact charger is preferred because it allows for an image forming device with reduced ozone emissions from the charger.

[0193] Preferably, the charger is configured to be in contact with or not in contact with the image carrier, and is configured to charge the surface of the image carrier in response to the application of superimposed DC and AC voltages.

[0194] Preferably, the charger is a charging roller having a gap band relative to the image carrier and being disposed near the image carrier without contacting it, and is configured to charge the surface of the image carrier in response to the application of superimposed DC and AC voltages to the charging roller.

[0195] -Exposure steps and exposure units-

[0196] The exposure step is the process of exposing the charged surface of the image carrier to light, and it is performed by the exposure unit. Exposure can be performed by using the exposure unit to image-constructively expose the surface of the image carrier.

[0197] The optical systems involved in exposure can be broadly classified into analog optical systems and digital optical systems.

[0198] An analog optical system is an optical system configured to project a copy of an image directly onto the surface of an image carrier via an optical system.

[0199] A digital optical system is an optical system configured to receive image information as an electrical signal, convert the electrical signal into an optical signal, and expose an image carrier to the optical signal to form an image.

[0200] There are no particular limitations on the exposure unit, and it can be appropriately selected according to the intended purpose, as long as the exposure unit can expose the charged image carrier and form a latent image on the image carrier. Examples of exposure units include various exposure devices, such as copier optical systems, rod lens array systems, laser optical systems, liquid crystal shutter optical systems, and LED optical systems.

[0201] In this disclosure, a backlight system configured to image-encapsulate the back of an image carrier may also be used.

[0202] -Fixing Steps and Fixing Unit-

[0203] The fixing step is the process of fixing the toner image transferred to the recording medium, and is performed by the fixing unit. When two or more colors of toner are used, each color of toner can be fixed separately when it is transferred to the recording medium, or they can be fixed in an overlay state when all colors of toner are transferred to the recording medium.

[0204] There are no particular limitations on the fixing unit, and it can be appropriately selected according to the intended purpose, as long as the fixing unit can fix the toner image transferred to the recording medium. A thermal fixing system using a known heating / pressurizing unit can be used.

[0205] There are no particular limitations on the heating / pressurizing unit, and it can be appropriately selected according to the intended purpose. Examples of heating / pressurizing units include combinations of heating rollers and pressure rollers, as well as combinations of heating rollers, pressure rollers, and annular belts.

[0206] There are no particular limitations on the heating temperature, which can be appropriately selected according to the intended purpose, and is preferably between 80°C and 200°C. As needed, for example, a known optical fixing device can be used in combination with the fixing unit.

[0207] - Charge elimination steps and charge elimination units-

[0208] The charge elimination step is a step of applying a charge elimination bias voltage to the image carrier to eliminate accumulated charge, and is performed by the charge elimination unit.

[0209] There are no particular limitations on the charge elimination unit, and it can be appropriately selected according to the intended purpose, as long as the charge elimination unit can apply a charge elimination bias voltage to the image carrier. Examples of charge elimination units include charge elimination lamps.

[0210] -Recycling steps and recycling units-

[0211] The recycling step is the process of recovering the toner removed during the cleaning step, and is performed by the recycling unit.

[0212] There are no particular limitations on the recycling unit, and it can be appropriately selected according to the intended purpose. Examples of recycling units include well-known conveying units.

[0213] -Control Procedures and Control Units-

[0214] The control step is the step that controls each of the above steps and is executed by the control unit.

[0215] There are no particular limitations on the control unit, and it can be appropriately selected according to the intended purpose, as long as the control unit can control the operation of each unit. Examples of control units include devices such as sequencers and computers.

[0216] <Image carrier>

[0217] For example, there are no particular restrictions on the structure and size of the image carrier, and an image carrier can be appropriately selected from known image carriers.

[0218] There are no particular restrictions on the shape of the image carrier, and it can be appropriately selected according to the intended purpose. Examples of image carrier shapes include drum-shaped and strip-shaped.

[0219] There are no particular limitations on the materials used for image carriers, and they can be appropriately selected according to the intended purpose. Examples of image carrier materials include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors (OPCs) such as polysilanes and phthalopolymethine.

[0220] Examples of the image forming apparatus of this disclosure will be described with reference to the accompanying drawings. The use of the cleaning scraper of this disclosure is not limited to the following embodiments.

[0221] The same reference numerals are used to denote the same parts in the accompanying drawings, and any redundant descriptions of the same parts may be omitted. For example, the number, location, and shape of the parts are not limited to those in the embodiments, and may be any number, location, and shape suitable for carrying out this disclosure.

[0222] Figure 4 This is a schematic diagram illustrating an example of the image forming apparatus of this disclosure. Figure 4 The image forming apparatus 10 includes four image forming units for yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and BK). These image forming units are configured identically, except that they use toners of Y, M, C, and BK, which have different colors from each other, as image forming substances for forming images.

[0223] Each image forming unit includes a photoconductor drum 21 (photoconductor drum 21C for cyan, photoconductor drum 21Y for yellow, photoconductor drum 21M for magenta, and photoconductor drum 21BK for black); a charging unit configured to uniformly charge the photoconductor drum 21; an exposure unit 12 configured to expose the photoconductor drum 21 based on image information for each color and form a latent image of each color on the photoconductor drum 21; a developing unit 20 (developing unit 20C for cyan, developing unit 20Y for yellow, developing unit 20M for magenta, and developing unit 20BK for black), which is a developing unit configured to develop the latent image with a developer of each color and form a toner image of each color; a transfer charger configured to transfer the toner image onto an intermediate transfer belt 22; a cleaning unit 13; and a charge elimination lamp.

[0224] The charging unit is a charging component belonging to a charging device used as a charging tool. The developing unit 20 is a developing unit configured to transform the latent image formed on the surface of the photoconductor drum 21 into a toner image. The cleaning unit 13 is a cleaning unit configured to clean toner residue remaining on the photoconductor drum 21 (from which the toner image has been transferred to the intermediate transfer belt 22). The charge elimination lamp (not shown) is a charge elimination unit configured to eliminate the surface potential on the photoconductor drum 21 after cleaning.

[0225] The photoconductive drum 21 has a drum shape. However, a sheet-shaped photoreceptor or an annular strip-shaped photoreceptor can also be used.

[0226] A transfer unit, including an intermediate transfer belt 22 used as an intermediate transfer medium, is disposed below each image forming unit. The intermediate transfer belt 22 is an annular belt tensioned and fitted onto three rollers 26, and can... Figure 4 The transfer rollers 23 (23C for cyan, 23Y for yellow, 23M for magenta, and 23BK for black) are positioned near the intermediate transfer belt 22, opposite to the intermediate transfer belt 22. A transfer bias (secondary transfer bias) can be applied to the transfer rollers 23 to transfer the developed image (toner image) onto the transfer paper P used as the recording medium (secondary transfer bias).

[0227] A cleaning blade 25 for the intermediate transfer medium and a lubricant application unit 27 are disposed near the roller 26. The cleaning blade is configured to remove residual toner from the intermediate transfer belt 22 (from which the toner image has been transferred to the recording paper P). The lubricant application unit serves as a mechanism configured to apply lubricant (e.g., zinc stearate) to the intermediate transfer medium. The cleaning blade 25 for the intermediate transfer medium contacts the intermediate transfer belt 22 in a direction opposite to the direction of movement of the intermediate transfer belt 22. Details of the cleaning blade 25 for the intermediate transfer medium are as described above.

[0228] The secondary transfer unit is located on the side of the intermediate transfer belt 22 opposite to the side where the image forming unit is located. The secondary transfer unit includes a secondary transfer belt 50, which is a ring-shaped belt tautly fitted onto a pair of rollers 60. Recording paper P fed onto the secondary transfer belt 50 via the paper feeding unit 14 and the calibration roller 16, along with the intermediate transfer belt 22, can contact each other between the rollers 26 and 60. A fixing unit 15 is located near the secondary transfer belt 50.

[0229] Example

[0230] The present disclosure will now be described through examples and comparative examples. This disclosure should not be construed as being limited to these examples and comparative examples. Unless otherwise specified, “parts” means “parts by weight”.

[0231] (Example 1)

[0232] <Production of scraper base>

[0233] Polyurethane elastomer sheets obtained through centrifugal casting, curing, and post-crosslinking were used as the edge layer and base layer. The average thickness and martensitic hardness (HM) of the edge layer and base layer are described below.

[0234] Average thickness: 2.0mm

[0235] Martens hardness (HM) of the edge layer: 1.0 N / mm 2

[0236] Martens hardness (HM) of the base layer: 1.1 N / mm 2

[0237] The scraper base is manufactured by bonding the edge layer and the base layer together. The scraper base is then bonded to the metal plate.

[0238] <Coating Production>

[0239] —Preparation of particulate dispersion A—

[0240] Five parts of polytetrafluoroethylene (PTFE) ultrafine powder (TF9201Z, obtained from 3MLimited, with a volume average particle size of 200 nm) were added to a threaded tube to prepare particulate dispersion A. These included 5 parts of polytetrafluoroethylene (PTFE) ultrafine powder (TF9201Z, obtained from 3MLimited, with a volume average particle size of 200 nm) used as the first fluorinated resin, 2 parts of VdF-HFP-TFE terpolymer formed from vinylidene fluoride (VdF), hexafluoropropylene (HFP) and tetrafluoroethylene (TFE) used as the second fluorinated resin, and 93 parts of 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (HFE-347, obtained from Tokyo Chemical Industry Co., Ltd.) used as the solvent for the fluorinated dispersion. The mixture was stirred, for example, with a stirrer.

[0241] —Preparation of particulate dispersion B—

[0242] A polymethyl methacrylate (PMMA) aqueous dispersion (MX100W, obtained from Nippon Shokubai Co., Ltd., with a volume average particle size of 150 nm) (95 parts) and a polyvinyl butyral (PVB) resin (ESLEC KW-M, obtained from Sekisui Chemical Co., Ltd., with a degree of acetalization of 24 ± 3 mol%) used as the second fluoropolymer resin (5 parts) were added to a threaded tube and stirred, for example, with a stirrer to prepare particulate dispersion B.

[0243] —Immersion—

[0244] One end face of the scraper base (which serves as the foremost point of the cleaning scraper) on the outer side surface of the scraper base (hereinafter referred to as the foremost point face of the cleaning scraper) is immersed in the particle dispersion A at a right angle relative to the horizontal plane to a depth of 2 mm from the foremost point face of the cleaning scraper, and rises at an upward speed of 1 mm / s. To gather the PTFE particles required for cleaning function to a portion of the foremost point face of the cleaning scraper (including the contact side), the scraper base is tilted at approximately 45°, as shown below. Figure 5 As shown. Then, the base of the scraper was dried at room temperature (25°C) for 30 minutes to produce the cleaning scraper of Production Example 1.

[0245] (Examples 2 to 8 and Comparative Examples 1 to 7)

[0246] The cleaning scrapers of Examples 2 to 8 and Comparative Examples 1 to 7 were produced in the same manner as in Example 1, except that the content of the first fluoropolymer in the cleaning scraper, the content of the second fluoropolymer in the cleaning scraper, the content of the dispersion solvent, the Martens hardness of the edge layer, the Martens hardness of the base layer, and the average thickness of the coating were changed as shown in Tables 1 to 4.

[0247] In Comparative Example 3, the base of the cleaning scraper was not coated. In Comparative Example 4, particulate dispersion B was used.

[0248] Assembly of Image Forming Equipment

[0249] Each of the cleaning blades obtained in Examples 1 to 8 and Comparative Examples 1 to 7 will be attached to a color multifunction peripheral device (IMAGIO MP C4500, obtained from Ricoh Company, Ltd., whose printer unit is constructed similarly to...) Figure 4 The image forming device is assembled on a processing cartridge (similar to the imaging device 10 shown in the figure).

[0250] The cleaning blade is attached to the image forming device with a linear load of 20 g / cm and a cleaning angle of 79°.

[0251] <Measurement of Martens Hardness>

[0252] The martensitic hardness of the edge layer and the base layer of the cleaning scraper obtained in Examples 1 to 8 and Comparative Examples 1 to 7 were measured.

[0253] According to ISO 14577, using a nano-indenter (ENT-3100, available from Elionix Inc.), the martensitic hardness (HM) was measured by pressing the Berkowitz indenter into the measurement position for 10 seconds under a load of 1,000 μN, holding the Berkowitz indenter in this position for 5 seconds, and then removing the Berkowitz indenter within 10 seconds under the same load rate. The results are presented in Tables 1 to 4.

[0254] The edge layer for measuring martensitic hardness is located 20 μm from the foremost ridge of the edge layer. The base layer for measuring martensitic hardness is located 20 μm from one end of the base layer.

[0255] Martens hardness is the average of measurements obtained at 4 to 6 points at each measurement location.

[0256] <Measurement of average coating thickness>

[0257] The average thickness of the coatings on the cleaning scrapers obtained in Examples 1 to 8 and Comparative Examples 1 to 7 was measured. The results are presented in Tables 1 to 4.

[0258] The average thickness can be measured by scraping a portion of the coating with, for example, a spatula or cotton swab and then using a contact surface roughness tester (SURFTEST SJ-500: available from Mitutoyo Corporation) to perform profile measurements on the scraped portion.

[0259] <Evaluation of Torque Increase Rate>

[0260] Using the image forming equipment described above, output was obtained under the conditions specified below, and the rate of change of torque, indicating an increase in the driving torque of the intermediate transfer medium, was measured. After output, the leading edge of the cleaning blade was observed using a laser microscope (LEXT OLS4500, obtained from Olympus Corporation) to evaluate the rate of torque increase according to the evaluation criteria below. The evaluation results are presented in Tables 1 to 4. In the evaluation criteria, "initial period" refers to the time period from the first to the fifth hundredth prints.

[0261] Environment: 23℃ / 45%RH

[0262] Paper passing condition: Blank chart

[0263] Number of output sheets: 5000 (A4 size, horizontal width)

[0264] -Evaluation Criteria-

[0265] A: The rate of change of torque indicating an increase in torque is less than or equal to 50% of the torque during the initial period, and the intermediate transfer media does not stop due to the increase in drive torque. Furthermore, when the leading edge of the cleaning blade is observed after output, there is not even any indication that the leading edge has curled up.

[0266] B: The rate of change of torque indicating an increase in torque is less than or equal to 50% of the torque during the initial period, and the intermediate transfer medium does not stop due to the increase in drive torque. However, when observing the very tip of the cleaning squeegee after output, there are traces of curling; however, this is not at a level where the toner would slide and is not a problem for actual use.

[0267] C: The intermediate transfer medium stops due to increased torque. Furthermore, when observing the very tip of the cleaning squeegee after output, there are traces of curling, indicating that the toner has slid across the surface, which is a problem in actual use.

[0268] Image quality assessment (cleaning performance)

[0269] Using the image forming equipment described above, output was obtained under the conditions specified below. Subsequently, the surface of the leading edge and intermediate transfer media of the cleaning blade was observed using a laser microscope (LEXT OLS4500, obtained from Olympus Corporation) to evaluate image quality according to the evaluation criteria described below. The evaluation results are presented in Tables 1 to 4.

[0270] Environment: 27℃ / 80%RH

[0271] Paper conditions: Print the chart three times per job, with each chart showing 5% of the image area.

[0272] Number of output sheets: 50,000 (A4 size, horizontal width)

[0273] -Evaluation Criteria-

[0274] A: No toner slippage due to poor cleaning properties was visually observed on either the printing paper or the intermediate transfer medium. Furthermore, no streaks of toner slippage were observed when the photoreceptor was examined under a microscope over a longer distance.

[0275] B: Toner slippage due to poor cleaning properties was not visually observed on either the printing paper or the intermediate transfer medium. However, streaks of toner slippage were observed when the photoreceptor was examined under a microscope over a longer direction.

[0276] C: Toner was visually observed to have slipped through due to poor cleaning properties on both the printing paper and the intermediate transfer medium.

[0277] Table 1

[0278]

[0279] Table 2

[0280]

[0281] Table 3

[0282]

[0283] Table 4

[0284]

[0285] For example, the aspects disclosed herein are as follows.

[0286] <1> A cleaning scraper for intermediate transfer media, the cleaning target of the cleaning scraper being the intermediate transfer media, the cleaning scraper comprising:

[0287] Edge layer; and

[0288] coating,

[0289] The coating disposed at the foremost point of the edge layer comprises a first fluoropolymer resin and a second fluoropolymer resin incompatible with the first fluoropolymer resin. The edge layer contacts the intermediate transfer medium at the foremost point.

[0290] The cleaning blade for intermediate transfer media has a strength of 0.5 N / mm at a position 20 μm away from the foremost ridge of the edge layer. 2 Or larger and 3N / mm 2 Or even lower Marsh hardness.

[0291] <2> according to <1> The cleaning scraper for intermediate transfer media,

[0292] The average thickness of the coating at a location 20 μm away from the foremost ridge of the edge layer is 2.0 μm or greater and 10.0 μm or less.

[0293] <3> according to <1> or <2> The cleaning scraper for intermediate transfer media,

[0294] The first fluoropolymer resin comprises polytetrafluoroethylene (PTFE), and

[0295] The first fluoropolymer resin consists of spherical particles with a volume average particle size of 1 μm or smaller.

[0296] <4> according to <1> to <3> The cleaning scraper for intermediate transfer media described in any one of the following statements,

[0297] The second fluoropolymer is a polymer of any monomer selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), a binary copolymer of any two monomers selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), or a terpolymer of three monomers selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE).

[0298] <5> according to <4> The cleaning scraper for intermediate transfer media,

[0299] The second fluoropolymer resin further includes fluorooil.

[0300] <6> according to <5> The cleaning scraper for intermediate transfer media,

[0301] The fluorinated oil has an average molecular weight of 2,000 to 3,500.

[0302] <7> according to <1> to <6> The cleaning scraper for intermediate transfer media described in any one of the following statements,

[0303] The base of the cleaning scraper used for intermediate transfer media has a single-layer structure formed of polyurethane rubber, or a laminated structure in which various polyurethane rubbers with different martensitic hardness are laminated.

[0304] <8> according to <7> The cleaning scraper for intermediate transfer media,

[0305] The martensitic hardness of the polyurethane rubber is 0.5 N / mm. 2 Or larger and 2N / mm 2 Or smaller.

[0306] <9> Image forming apparatus, comprising:

[0307] The developing unit is configured to develop a latent image formed on an image carrier capable of carrying a toner image using a toner;

[0308] A primary transfer unit is configured to transfer a toner image obtained by development in a developing unit onto an intermediate transfer medium in a single transfer; and

[0309] The cleaning unit is configured to remove toner residues on the surface of the intermediate transfer medium.

[0310] The cleaning unit thereon is a cleaning scraper for intermediate transfer media according to any one of <1> to <8>.

[0311] The cleaning scraper according to any one of <1> to <8> and the image forming apparatus according to <9> can solve various problems in the prior art and achieve the purpose of this disclosure.

[0312] Furthermore, the present invention is not limited to these embodiments, but can be varied and modified in various ways without departing from the scope of the present invention.

Claims

1.A cleaning blade for an intermediate transfer medium, the cleaning target of which is an intermediate transfer medium, the cleaning blade comprising: an edge layer; and a coating layer, wherein the coating layer disposed on a most front end of the edge layer, which contacts the intermediate transfer medium at the most front end, contains a first fluorine-based resin and a second fluorine-based resin that is incompatible with the first fluorine-based resin, and The cleaning blade for an intermediate transfer medium has a Martens hardness of 0.5 N / mm 2 or more and 3 N / mm 2 or less at a position 20 μm from the ridge portion of the frontmost end of the edge layer. 2.The cleaning blade for an intermediate transfer medium according to claim 1, wherein the average thickness of the coating layer at a position 20 μm from a ridge portion of the most front end of the edge layer is 2.0 μm or more and 10.0 μm or less. 3.The cleaning blade for an intermediate transfer medium according to claim 1 or 2, wherein the first fluorine-based resin contains polytetrafluoroethylene (PTFE), and the first fluorine-based resin is a spherical particle having a volume average particle diameter of 1 μm or less. 4.The cleaning blade for an intermediate transfer medium according to any one of claims 1 to 2, wherein the second fluorine-based resin is a polymer of any one monomer selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), a binary copolymer of any two monomers selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE), or a ternary copolymer of the three monomers selected from vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE). 5.The cleaning blade for an intermediate transfer medium according to claim 4, wherein the second fluorine-based resin further includes a fluorine-based oil. 6.The cleaning blade for an intermediate transfer medium according to claim 5, wherein the average molecular weight of the fluorine-based oil is 2,000 to 3,500. 7.The cleaning blade for an intermediate transfer medium according to any one of claims 1 to 2, wherein the base of the cleaning blade for an intermediate transfer medium has a single layer structure formed of polyurethane rubber, or a laminated structure in which a plurality of polyurethane rubbers having different Martens hardnesses are laminated. 8.The cleaning blade for an intermediate transfer medium according to claim 7, wherein the polyurethane rubber has a Martens hardness of 0.5 N / mm 2 or more and 2 N / mm 2 or less. 9.An image forming apparatus comprising: a developing unit configured to develop a latent image formed on an image bearer capable of bearing a toner image with toner; a primary transfer unit configured to primary transfer a toner image obtained by the developing unit onto an intermediate transfer medium; and a cleaning unit configured to remove the toner remaining on the surface of the intermediate transfer medium, wherein the cleaning unit is the cleaning blade for an intermediate transfer medium according to any one of claims 1 to 8. ​

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