Patent Description:
In electrophotographic image forming processes, a cleaning device that removes residual toner adhering to a surface of an image bearer is used. As the cleaning device, a cleaning blade composed of an elastic body made of polyurethane rubber and a support supporting the elastic body is widely used. After the cleaning blade has cleaned the image bearer, a lubricant supply device supplies a lubricant to the surface of the image bearer. As the lubricant supply device, a lubricant leveling blade composed of an elastic body made of polyurethane rubber and a support supporting the elastic body is widely used. It is known that a lubricant, such as a metal soap, is applied to the tip edge portion of the elastic body of each of the cleaning blade and lubricant leveling blade.

The cleaning blade and the lubricant leveling blade are required to have lubricity for preventing an increase in torque, which is a force necessary for rotating the image bearer, and reducing a frictional force with the image bearer. In addition, the lubricant applied to the cleaning blade and lubricant leveling blade is required to have an adhesive force to their substrates to be prevented from being detached therefrom.

In attempting to reduce a frictional force between the cleaning blade and the image bearer, a cleaning blade coated with a lubricant containing a fluorine-based compound has been proposed, where the fluorine-based compound is vinylidene fluoride (for example, as in Patent Literatures <NUM> to <NUM>). In attempting to impart appropriate flexibility and hardness to the elastic body of the cleaning blade and preventing curling or gouging wear of the tip edge portion of the cleaning blade, a cleaning blade having a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from the tip edge portion of the elastic body has been proposed (for example, as in Patent Literature <NUM>). Further, in attempting to improve slidability of the cleaning blade, a cleaning blade coated with a dispersion of PMMA (i.e., polymethacrylic acid) particles in a fluorine-based solvent has been proposed (for example, as in Patent Literature <NUM>). Document <CIT> discloses a cleaning blade comprising an elastic member including a contact portion to contact the surface of a member to be cleaned and remove an extraneous matter adhering to the surface of the member.

An object of the present invention is to provide a cleaning blade capable of reducing an increase in torque even immediately after the start of use of an image forming apparatus to exhibit excellent cleaning performance.

Embodiments of the present invention provide a cleaning blade for cleaning a rotating body. The cleaning blade includes: an edge layer having a tip portion that comes into contact with the rotating body; and a coating layer on the tip portion of the edge layer. The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin. The cleaning blade has a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer.

Embodiments of the present invention provide a lubricant leveling blade for leveling a lubricant applied onto a rotating body. The lubricant leveling blade includes: an edge layer having a tip portion that comes into contact with the rotating body; and a coating layer on the tip portion of the edge layer. The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin. The lubricant leveling blade has a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer.

Embodiments of the present invention provide a process cartridge. The process cartridge includes: an image bearer; at least one of a charger to charge a surface of the image bearer, an irradiator to irradiate the charged surface of the image bearer to form an electrostatic latent image, a developing device to develop the electrostatic latent image into a visible image, or a transfer device to transfer the visible image onto a recording medium; and a cleaning device to remove a residue on the surface of the image bearer that contains the above-described cleaning blade.

Embodiments of the present invention provide an image forming apparatus. The image forming apparatus includes: an image bearer; a charger to charge a surface of the image bearer; an irradiator to irradiate the charged surface of the image bearer to form an electrostatic latent image; a developing device to develop the electrostatic latent image into a visible image; a transfer device to transfer the visible image onto a recording medium; a fixing device to fix the transferred visible image on the recording medium; and a cleaning device to remove a residue on the surface of the image bearer that contains the above-described cleaning blade.

In accordance with some embodiments of the present invention, a cleaning blade is provided that is capable of reducing an increase in torque even immediately after the start of use of an image forming apparatus to exhibit excellent cleaning performance.

However, the disclosure of this specification is not intended to be limited to the specific terminology so selected.

A cleaning blade of the present embodiment is for cleaning a rotating body. The cleaning blade comprises an edge layer and a coating layer. The edge layer has a tip portion that comes into contact with the rotating body. The coating layer is disposed on the tip portion of the edge layer. The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin. The cleaning blade has a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer. The cleaning blade may further include other members, as necessary.

The cleaning blade of the present embodiment comes into contact with a surface of a rotating body to remove a residue adhering to the rotating body.

The residue is not particularly limited as long as it is adhering to the surface of the rotating body and is to be removed by the cleaning blade. Examples of the residue include, but are not limited to, toner, lubricant, inorganic particles, organic particles, dust, and mixtures thereof.

A conventional cleaning blade has a drawback that, as the cleaning blade comes into contact with the rotating body (e.g., image bearer), the torque that is a force required for rotating the rotating body increases due to friction generated between the cleaning blade and the rotating body, and the rotating body thereby stops rotating. In addition, due to the friction, the contact portion of the cleaning blade with the rotating body gets worn. The cleaning blade thereby turns up and allows toner to slip therethrough, resulting in defective cleaning.

In attempting to improve slidability of the cleaning blade and preventing the cleaning blade from turning up or increasing the torque, a process called "touch-up" is widely employed for applying a lubricant, such as a metal soap (e.g., zinc stearate) and PMMA (i.e., polymethacrylic acid) particles, to the tip portion of the cleaning blade. Normally, with the operation of the image forming apparatus, toner gradually accumulates between the cleaning blade and the image bearer and functions as a lubricant. Therefore, the lubricant needs to exhibit a lubricating property for a short period of time from when the image forming apparatus starts operating until the behavior of the cleaning blade gets stabilized. However, fine particles contained in the conventional lubricant have a weak adhesive force to the substrate and undesirably detach from the cleaning blade before the behavior of the cleaning blade gets stabilized.

It is known that prevention of an increase in torque and improvement in the cleaning performance are in a trade-off relationship.

When the contact part of the cleaning blade with the rotating body is smoothened by application of a lubricant thereto for the purpose of preventing an increase in torque, toner is allowed to pass through the contact part, resulting in deterioration of the cleaning performance.

When the contact part of the cleaning blade with the rotating body is made uneven to increase a frictional force for the purpose of improving the cleaning performance, the torque increases. It has been difficult to prevent an increase in torque and to improve the cleaning performance at the same time.

As a result of diligent studies, the inventors of the present invention have found that detachment of particles can be prevented by forming a coating layer on the cleaning blade by applying a liquid dispersion of the particles in a mixture of a solvent and a binder component, rather than a liquid dispersion of the particles only in a solvent. Further, the inventors have found that the use of fluorine-based materials having slidability for the particles and the binder component can prevent either the cleaning blade from turning up or the torque of the image bearer from increasing.

In addition, the present inventors have found that when the Martens hardness at a position <NUM> distant from the tip edge portion of the edge layer is from <NUM> to <NUM> N/mm<NUM>, a sliding effect is exerted without adversely affecting the cleaning function.

Accordingly, the cleaning blade of the present embodiment is for cleaning a rotating body. The cleaning blade comprises an edge layer and a coating layer. The edge layer has a tip portion that comes into contact with the rotating body. The coating layer is disposed on the tip portion of the edge layer. The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin. The cleaning blade has a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer. This cleaning blade is capable of reducing an increase in torque even immediately after the start of use of an image forming apparatus to exhibit excellent cleaning performance.

The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin, and further contains other components as necessary.

The coating layer refers to a layer provided on one end portion on peripheral side surfaces of a blade substrate (to be described later), which is used as a tip of the cleaning blade.

The coating layer may be formed on at least a part of the blade substrate, including a contact edge of the cleaning blade that comes into contact with the rotating body. The coating layer may be formed on the entire of the contact edge, or on the entire surface of the blade substrate. Among these, it is preferable that the coating layer be formed on the entire of the contact edge.

In the present disclosure, a surface region of the blade substrate where the coating layer is not provided may be referred to as a non-coating region.

In the present disclosure, "incompatibility" refers to a property of multiple substances incompletely mixed with each other with forming interfaces therebetween, and "compatibility" refers to a property of multiple substances completely mixed with each other without forming interfaces therebetween.

In the present disclosure, "incompatible state" refers to a state in which an interface is present between the first fluorine-based resin and the second fluorine-based resin, where a part thereof may be compatibilized.

In one preferred embodiment of the incompatible state, the coating layer has a sea-island structure.

The sea-island structure refers to a structure of the coating layer formed on the cleaning blade, in which a continuous phase of one component is expressed as "sea (or "matrix")" and other components are expressed as "islands (or "domains")" formed in the "sea".

In the present disclosure, the sea-island structure indicates a state in which the first fluorine-based resin serving as domains and the second fluorine-based resin serving as a matrix are incompatible with each other and no compatibilized portion is present.

When the coating layer has such a sea-island structure, it is preferable that the domains be in the form of particles.

Preferably, the coating layer of the cleaning blade has an average thickness of from <NUM> to <NUM>.

When the average thickness of the coating layer is <NUM> or more, the sliding effect is sufficiently exerted. When the average thickness of the coating layer is <NUM> or less, the coating layer is prevented from falling off.

The average thickness of the coating layer may be an average value of thicknesses (µm) measured at three or more positions of the coating layer.

The positions at which the thickness of the coating layer is measured are not particularly limited, and may include a position <NUM> distant from both end portions of the coating layer and a central portion of the coating layer.

The average thickness of the coating layer can be measured by scraping off a part of the coating layer with a spatula, a cotton swab, or the like and measuring the shape thereof using a three-dimensional measuring instrument such as a contact surface roughness meter (SURFTEST SJ-<NUM>, product of Mitutoyo Corporation) or a laser microscope (LEXT OLS4100, product of Olympus Corporation).

The cleaning blade according to an embodiment of the present invention is described below with reference to the drawings. The applications of the cleaning blade are provided herein for the purpose of illustration only and are not intended to be limiting.

In each drawing, the same reference numerals are given to the same components, and redundant explanation may be omitted. The number, position, shape, and the like of the constituent members are not limited to those in the embodiments described below, and can be suitably set to suit to a particular application.

<FIG> is a schematic cross-sectional diagram illustrating a cleaning blade of the present embodiment in contact with a surface of a rotating body. <FIG> is a perspective view of the cleaning blade in <FIG> including an enlarged view of the vicinity of its contact part. A cleaning blade <NUM> includes a cleaning blade support <NUM> and a cleaning blade substrate <NUM>. The cleaning blade support <NUM> is a flat plate made of a rigid material such as metal or hard plastic. The cleaning blade substrate <NUM> has one end coupled to the cleaning blade support <NUM> and the other end being a free end having a specific length. The cleaning blade substrate <NUM> is fixed to one end portion of the cleaning blade support <NUM> with an adhesive or the like. The other end portion of the cleaning blade support <NUM> is supported by a casing of a cleaning device in a cantilever manner. The cleaning blade substrate <NUM> has a cleaning blade tip surface 62a, a cleaning blade lower surface 62b, a cleaning blade contact part 62c that is one end of the cleaning blade substrate <NUM> on the free end side, and a cleaning blade side surface 62d. Further, the cleaning blade substrate <NUM> has a coating layer <NUM> in at least a part including a contact edge in the cleaning blade contact part 62c.

The cleaning blade <NUM> is disposed such that the cleaning blade contact part 62c is in contact with a photoconductor <NUM> along the longitudinal direction.

<FIG> is a cross-sectional diagram of a cleaning blade according to another embodiment of the present invention. A cleaning blade <NUM> includes a cleaning blade support <NUM> and a cleaning blade substrate <NUM>. The cleaning blade substrate <NUM> includes an edge layer 622a and a base layer 622b both having elasticity, a contact part 62c, and a coating layer <NUM> in at least a part including a contact edge in the contact part 62c. The cleaning blade tip surface 62a, the cleaning blade lower surface 62b, and the cleaning blade side surface 62d are omitted from the drawing.

In the present disclosure, the fluorine-based resin refers to a resin containing fluorine in its molecule. The fluorine-based resin is preferably an olefin polymer containing fluorine, and more preferably an olefin polymer in which hydrogen atoms are substituted with fluorine atoms.

In one preferred embodiment of the present invention, the first fluorine-based resin forms domains in the sea-island structure of the coating layer.

Preferably, the type and addition amount of the first fluorine-based resin is so selected that the first fluorine-based resin can form domains in the second fluorine-based resin.

The shapes of the domains are not particularly limited and may be suitably selected to suit to a particular application, and may be either regular or irregular. Preferably, the shapes of the domains are regular.

When the shapes of the domains are regular, it is preferable that the shapes be spherical. When the shapes of the domains are spherical, it is preferable that the domains be in the form of particles.

The fluorine-based resin in such a shape is prevented, when fallen off from the coating layer, from damaging the rotating body or the blade substrate of the cleaning blade.

The volume average particle diameter (e.g., <NUM>% volume diameter, median diameter) of the first fluorine-based resin is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM> to <NUM>, more preferably <NUM> or less, and still more preferably <NUM> or less. When the volume average particle diameter is <NUM> or less, the first fluorine-based resin is prevented from being precipitated and unstably dispersed in a solvent. When the volume average particle diameter is <NUM> or less, the first fluorine-based resin can be more stably dispersed in a non-aqueous solvent.

A method for measuring the volume average particle diameter (e.g., <NUM>% volume diameter, median diameter) is not particularly limited and can be suitably selected to suit to a particular application, and may be laser diffraction/scattering, dynamic light scattering, or imaging. The volume average particle diameter may be measured, for example, by collecting the particles from the coating layer of the cleaning blade and subjecting the particles to a laser diffraction/scattering measurement using an instrument MICROTRAC (product of Nikkiso Co. ), or by directly observing and measuring the particles on the cleaning blade using a scanning electron microscope (SEM).

The volume average particle diameter of the particles present in the coating layer is almost the same as that of the particles before being added to the dispersion liquid to be applied to the cleaning blade.

The proportion of the first fluorine-based resin in the coating layer is not particularly limited and may be suitably selected to suit to a particular application. To achieve the sliding effect, the proportion is preferably from <NUM>% to <NUM>% by mass, and more preferably from <NUM>% to <NUM>% by mass. The sliding effect achieved by inclusion of the first fluorine-based resin is maximized when the proportion of the first fluorine-based resin in the coating layer is <NUM>% by mass. When the proportion of the first fluorine-based resin in the coating layer is <NUM>% by mass or more, the sliding effect is sufficiently exerted.

Specific examples of the first fluorine-based resin include, but are not limited to, polytetrafluoroethylene (PTFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), chlorotrifluoroethylene copolymer (CTFE), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE/CTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and polychlorotrifluoroethylene (PCTFE). Among these, polytetrafluoroethylene (PTFE) is preferred for further improving the slidability of the cleaning blade.

The polytetrafluoroethylene (PTFE) is available either by synthesis or from commercial products.

Specific examples of commercial products of the polytetrafluoroethylene (PTFE) include, but are not limited to, DYNEON TF MICROPOWDER TF-9201Z and DYNEON TF MICROPOWDER TF-9207Z (products of <NUM> Company), NanoFLON 119N and FLUORO E (products of Shamrock Technologies), TLP10F-<NUM> (product of DuPont-Mitsui Fluorochemicals, Co. ), KTL-500F (product of KITAMURA LIMITED), and ALGOFLON L203F (product of Solvay S.

The coating layer further contains the second fluorine-based resin to improve the adhesive force of the first fluorine-based resin to the cleaning blade substrate and prevent detachment of the coating layer. Thus, the cleaning blade is prevented from turning up, and an increase in torque is prevented.

In one preferred embodiment of the present invention, the second fluorine-based resin forms a matrix in the sea-island structure of the coating layer.

Preferably, the type and addition amount of the second fluorine-based resin is so selected that the second fluorine-based resin can form a matrix for the first fluorine-based resin.

The second fluorine-based resin is not particularly limited and may be suitably selected to suit to a particular application as long as the first fluorine-based resin can be uniformly and stably dispersed therein. Specific examples thereof include, but are not limited to, vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE). Among these, for improving lubricity and adhesion to the blade substrate, a copolymer of these materials is preferred, and a VdF-HFP-TFE terpolymer is more preferred.

Preferably, the proportions of VdF, HFP, and TFE in the VdF-HFP-TFE terpolymer are <NUM>% to <NUM>% by mol, <NUM>% to <NUM>% by mol, and <NUM>% to <NUM>% by mol, respectively, for imparting flexibility to the blade and solubility in solvents.

The second fluorine-based resin may be mixed with a fluorine-based oil.

The fluorine-based oil improves not only a binder function but also a sliding function. Specific examples of the fluorine-based oil include, but are not limited to, those having a tetrafluoroethylene (TFE) oligomer or a perfluoroether as the main backbone.

In the case of a mixture of the second fluorine-based resin with the fluorine-based oil, the proportion of the second fluorine-based resin in the mixture is preferably from <NUM>% to <NUM>% by mass, more preferably from <NUM>% to <NUM>% by mass, for preventing the fluorine-based oil from bleeding out and contaminating a photoconductor.

The fluorine-based oil having a perfluoroether as the main backbone is not particularly limited and can be suitably selected to suit to a particular application as long as it has slidability and does not inhibit dispersion of the fluorine-based resin. Considering kinematic viscosity, those having an average molecular weight of from <NUM>,<NUM> to <NUM>,<NUM> are preferred.

In the present disclosure, the first fluorine-based resin and the second fluorine-based resin may be either the same materials or different materials. When the first fluorine-based resin and the second fluorine-based resin are the same materials, the coating layer can be formed by a method of putting the first fluorine-based resin and the second fluorine-based resin into an incompatible state. For example, when the first fluorine-based resin is cured in advance and the second fluorine-based resin is added thereto and cured, an interface is formed between the first fluorine-based resin and the second fluorine-based resin, thus forming a coating layer in which the first fluorine-based resin and the second fluorine-based resin are partially incompatible. The coating layer can also be formed by adding a hydrophilic substituent to the first fluorine-based resin and adding a hydrophobic substituent to the second fluorine-based resin.

The other components are not particularly limited and may be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, non-fluorine-based resin particles that are not composed of the fluorine-based resin described above.

The non-fluorine-based resin particles are not particularly limited and may be suitably selected to suit to a particular application. Specific examples thereof include particles of inorganic compounds, acrylic resins, styrene resins, and vinyl resins.

Specific examples of the inorganic compound particles include, but are not limited to, silica, alumina, and zirconia.

Each of these can be used alone or in combination with others.

The shapes of the non-fluorine-based resin particles are not particularly limited and can be suitably selected to suit to a particular application, but the non-fluorine-based resin particles are preferably spherical. The non-fluorine-based resin particles in such a shape are prevented, when fallen off from the coating layer, from damaging the rotating body or the blade substrate of the cleaning blade.

The volume average particle diameter (e.g., <NUM>% volume diameter, median diameter) of the non-fluorine-based resin particles is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM> to <NUM>, more preferably <NUM> or less, and still more preferably <NUM> or less. When the volume average particle diameter is <NUM> or less, the non-fluorine-based resin particles are prevented from being precipitated and unstably dispersed in a solvent. When the volume average particle diameter is <NUM> or less, the non-fluorine-based resin particles can be more stably dispersed in a non-aqueous solvent.

A method for forming the coating layer is not particularly limited and can be suitably selected to suit to a particular application. For example, the coating layer can be formed by adding the first fluorine-based resin to a mixture (i.e., a second fluorine-based resin dispersion) of a solvent and the second fluorine-based resin, mixing them, and applying the resulting particle dispersion to the blade substrate of the cleaning blade.

The solvent is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include fluorine-containing organic solvents.

Specific examples of the fluorine-containing organic solvents include, but are not limited to, hydrofluoroether (HFE), perfluorocarbon (PFC), and perfluoroether (PFE).

Preferably, an average particle diameter of the particles in the second fluorine-based resin dispersion measured by a dynamic light scattering method (e.g., an average particle diameter measured by a cumulant analysis method in scattering intensity distribution) is <NUM> or less, more preferably <NUM> or less, and even more preferably <NUM> or less.

Generally, fine particles having a volume average particle diameter of <NUM> or less usually agglomerate into secondary particles having a particle diameter of <NUM> or more. Thus, when the secondary particles formed by agglomeration are dispersed in a manner that they have a particle diameter of <NUM> or less, the second fluorine-based resin dispersion is maintained stable even when stored at a low viscosity for a long period of time.

The dispersing method is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, methods using a disperser such as ultrasonic disperser, three roll mill, ball mill, bead mill, and jet mill.

A method for forming the coating layer is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, dipping in which the entire or a part of the blade substrate of the cleaning blade is dipped in a particle dispersion. In addition to dipping, spray coating or dispenser coating may also be employed.

In the present disclosure, the blade substrate of the cleaning blade may also be simply referred to as "substrate".

The shape of the blade substrate may be suitably selected to suit to a particular application as long as the blade substrate has a structure capable of removing a residue on the rotating body. Preferably, the contact edge in the contact part of the blade substrate that comes into contact with the rotating body is linear. The blade substrate may have, for example, a plate shape.

The structure of the blade substrate is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, a monolayer structure, a laminated structure, and a laminated structure which combines multiple members. Among these, a monolayer structure and a laminated structure which combines multiple members are preferred in view of easy processing into the cleaning blade.

In the case in which the blade substrate has a laminated structure, a layer abutting the rotating body may be referred to as an edge layer, and a layer other than the edge layer may be referred to as a base layer. In the case in which the blade substrate has a monolayer structure, the blade substrate consists only of an edge layer.

In the case of a laminated structure which combines multiple members, it is preferable that the Martens hardness values of the multiple members be different from each other.

The material of the blade substrate is not particularly limited and can be suitably selected to suit to a particular application. For preventing wear of the blade substrate and sufficiently removing the residue from the rotating body, it is preferable that the material have appropriate elasticity and hardness. The material of the blade substrate may be, for example, an elastic material.

The elastic material is not particularly limited and may be suitably selected to suit to a particular application as long as it has high elasticity. Specific examples thereof include, but are not limited to, polyurethane rubber, silicone rubber, fluororubber, nitrile rubber (NBR), and ethylene propylene diene rubber (EPDM). Among these, polyurethane rubber is preferred for its durability and non-staining properties.

The size of the blade substrate is not particularly limited and may be suitably selected depending on the size of the rotating body.

The Martens hardness of the polyurethane rubber in the cleaning blade of the present embodiment is preferably from <NUM> to <NUM> N/mm<NUM>. When the Martens hardness of the polyurethane rubber in the cleaning blade is within the above desired range, undesirable phenomena such as defective cleaning and chipping can be prevented. Here, the defective cleaning is caused when the linear pressure of the blade hardly achieves a desired level and the area of the contact part with an image bearer increases, and the chipping is caused when the blade substrate is excessively hard.

A method for producing the blade substrate is not particularly limited and can be suitably selected to suit to a particular application. For example, the blade substrate can be produced through the processes of: preparing a polyurethane prepolymer from a polyol compound and a polyisocyanate compound; adding a curing agent, optionally along with a curing catalyst, to the polyurethane prepolymer; centrifugal molding the resultant using a mold; leaving the resultant at room temperature for aging; and cutting the resultant into a flat plate having a predetermined size.

The polyol compound is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, high-molecular-weight polyols and low-molecular-weight polyols.

Specific examples of the high-molecular-weight polyols include, but are not limited to, a polyester polyol which is a condensate of an alkylene glycol and an aliphatic diprotic acid; polyester-based polyols, such as polyester polyols of alkylene glycols with adipic acid, such as ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene butylene adipate ester polyol, and ethylene neopentylene adipate ester polyol; polycaprolactone-based polyols such as polycaprolactone ester polyols obtained by ring-opening polymerization of caprolactone; and polyether-based polyols such as poly(oxytetramethylene) glycol and poly(oxypropylene) glycol.

Specific examples of the low-molecular-weight polyols include, but are not limited to, divalent alcohols such as <NUM>,<NUM>-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis(<NUM>-hydroxyethyl) ether, <NUM>,<NUM>'-dichloro-<NUM>,<NUM>'-diaminodiphenylmethane, and <NUM>,<NUM>'-diaminodiphenylmethane; and trivalent or higher polyols such as <NUM>,<NUM>,<NUM>-trimethylolpropane, glycerin, <NUM>,<NUM>,<NUM>-hexanetriol, <NUM>,<NUM>,<NUM>-butanetriol, trimethylolethane, <NUM>,<NUM>,<NUM>-tris(hydroxyethoxymethyl)propane, diglycerin, and pentaerythritol.

The polyisocyanate compound is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, methylene diphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthylene <NUM>,<NUM>-diisocyanate (NDI), tetramethylxylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), and trimethylhexamethylene diisocyanate (TMDI).

The curing agent is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, amines and alcohols.

The curing agent can be used to adjust the hardness of the blade substrate.

The curing catalyst is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, <NUM>-methylimidazole and <NUM>,<NUM>-dimethylimidazole.

The proportion of the curing catalyst to the total mass of the prepolymer and the curing agent is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM>% to <NUM>% by mass, more preferably from <NUM>% to <NUM>% by mass.

The rebound resilience according to the Japanese Industrial Standards (JIS) K6255 of the blade substrate is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM>% to <NUM>% at <NUM>.

When the rebound resilience is within the desired range, undesirable phenomena such as defective cleaning and blade squeak can be prevented. Here, the defective cleaning occurs when the entire blade substrate has lost flexibility and becomes unable to follow the runout or roughness of the image bearer, and the blade squeak (i.e., abnormal sound) occurs when the resilience becomes too strong.

The rebound resilience of the blade substrate can be measured according to JIS K6255 at <NUM> using, for example, a resilience tester No. <NUM>, product of Toyo Seiki Seisaku-sho, Ltd.

When the Martens hardness of the cleaning blade at a position <NUM> distant from the tip edge portion of the edge layer is from <NUM> to <NUM> N/mm<NUM>, the sliding effect is sufficiently exerted. Preferably, the Martens hardness of the cleaning blade at a position <NUM> distant from the tip edge portion of the edge layer is from <NUM> to <NUM> N/mm<NUM> for exerting an excellent sliding effect. When the Martens hardness of the cleaning blade at a position <NUM> distant from the tip edge portion of the edge layer is <NUM> N/mm<NUM> or more, an undesired phenomenon in which the first fluorine-based resin and the second fluorine-based resin are not sufficiently adhering to the edge layer without achieving a desired level of the sliding effect can be prevented. When the Martens hardness of the cleaning blade at a position <NUM> distant from the tip edge portion of the edge layer is <NUM> N/mm<NUM> or less, an undesired phenomenon in which the first fluorine-based resin and the second fluorine-based resin are excessively adhering to the edge layer to inhibit the cleaning function can be prevented.

In the present disclosure, the measurement of the Martens hardness is performed on the cleaning blade having been processed.

The Martens hardness (HM) can be measured according to ISO <NUM> using a nanoindenter (ENT-<NUM>, product of ELIONIX INC. ) by pushing a Berkovich indenter into a sample with a load of <NUM>,<NUM>µN for <NUM> seconds, holding for <NUM> seconds, and pulling the indenter with the same loading rate for <NUM> seconds.

The Martens hardness of the edge layer is measured at a position <NUM> distant from the tip edge portion of the edge layer.

The Martens hardness of the base layer may be measured at any position, but is preferably measured at a position <NUM> distant from an end portion of the base layer for ease of measurement.

The Martens hardness is the median of the numerical values measured at <NUM> to <NUM> positions.

The rotating body is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, an image bearer and a photoconductor.

The structure and size of the rotating body are not particularly limited and can be suitably selected to suit to a particular application.

The material of the rotating body is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, metals, plastics, and ceramics.

The shape of the rotating body is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, a drum shape, a belt shape, a flat plate shape, and a sheet shape.

The other members are not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, a support.

The shape of the support is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, a plate shape.

The structure of the support is not particularly limited and can be suitably selected to suit to a particular application.

The size of the support is not particularly limited and can be suitably selected according to the size of the rotating body.

The material of the support is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, metals, plastics, and ceramics. Among these, metals are preferred for their strength, and steels (e.g., stainless steel), aluminum, and phosphor bronze are particularly preferred.

The cleaning blade of the present embodiment can be used as a lubricant leveling blade for leveling a lubricant applied onto the surface of the rotating body after the cleaning blade has cleaned the rotating body.

The lubricant leveling blade of the present embodiment is for leveling a lubricant applied onto a rotating body. The lubricant leveling blade comprises an edge layer and a coating layer. The edge layer has a tip portion that comes into contact with the rotating body. The coating layer is disposed on the tip portion of the edge layer. The coating layer contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin. The lubricant leveling blade has a Martens hardness of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer. The lubricant leveling blade may further include other members, as necessary.

In the case of using the cleaning blade as a lubricant leveling blade, when the Martens hardness at a position <NUM> distant from the tip edge portion of the edge layer is from <NUM> to <NUM> N/mm<NUM>, the lubricant applying performance is well exerted.

The lubricant leveling blade according to the present embodiment is described below with reference to the drawings.

<FIG> is a schematic cross-sectional diagram illustrating a lubricant leveling blade of the present embodiment. <FIG> is a schematic cross-sectional diagram illustrating the lubricant leveling blade in <FIG> in contact with a surface of a rotating body. A lubricant leveling blade <NUM> includes a lubricant leveling blade support <NUM> and a lubricant leveling blade substrate <NUM>. The lubricant leveling blade support <NUM> is a flat plate made of a rigid material such as metal or hard plastic. The lubricant leveling blade substrate <NUM> has one end coupled to the lubricant leveling blade support <NUM> and the other end being a free end having a specific length. The lubricant leveling blade substrate <NUM> is fixed to one end portion of the lubricant leveling blade support <NUM> with an adhesive or the like. The other end portion of the lubricant leveling blade support <NUM> is supported by a casing of a cleaning device in a cantilever manner.

The lubricant leveling blade substrate <NUM> has a lubricant leveling blade tip surface 104a, a lubricant leveling blade lower surface 104b, and a lubricant leveling blade contact part 104c that is one end of the lubricant leveling blade substrate <NUM> on the free end side. Further, the lubricant leveling blade substrate <NUM> may have the same layer structure as the cleaning blade illustrated in <FIG> in at least a part including a contact edge in the lubricant leveling blade contact part 104c.

An image forming apparatus of the present embodiment includes: an image bearer; a charger to charge a surface of the image bearer; an irradiator to irradiate the charged surface of the image bearer to form an electrostatic latent image; a developing device to develop the electrostatic latent image into a visible image; a transfer device to transfer the visible image onto a recording medium; a fixing device to fix the transferred visible image on the recording medium; and a cleaning device to remove a residue (e.g., toner) on the surface of the image bearer. The image forming apparatus may further include a lubricant applying device to apply a lubricant to the surface of the image bearer and other devices as necessary.

The charger and the irradiator may be collectively referred to as an "electrostatic latent image forming device".

The cleaning device and the lubricant applying device respectively includes the cleaning blade and the lubricant leveling blade according to some embodiments of the present invention.

An image forming method of the present embodiment includes a charging process, an irradiation process, a developing process, a transfer process, a fixing process, and a cleaning process, and further includes a lubricant applying process and other processes as necessary. The charging and irradiation processes may be collectively referred to as an "electrostatic latent image forming process".

The image forming method is suitably performed by the image forming apparatus. The charging process can be performed by the charger. The irradiation process can be performed by the irradiator. The developing process can be performed by the developing device. The transfer process can be performed by the transfer device. The fixing process can be performed by the fixing device. The cleaning process can be performed by the cleaning device. The cleaning device contains the cleaning blade of the present embodiment. The lubricant applying process can be performed by the lubricant applying device, and the lubricant applying device contains the lubricant leveling blade of the present embodiment. The other processes can be performed by the other corresponding devices.

The structure and size of the image bearer are not particularly limited and can be suitably selected from known ones.

The shape of the image bearer is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, a drum shape and a belt shape.

The material of the image bearer is not particularly limited and can be suitably selected to suit to a particular application. Examples thereof include, but are not limited to, inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors (OPC) such as polysilane and phthalopolymethine.

The charging process is a process of charging the surface of the image bearer, and is performed by the charger.

The charger is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of charging the surface of the image bearer. Specific examples thereof include, but are not limited to, contact chargers equipped with a conductive or semiconductive roller, brush, film, or rubber blade and non-contact chargers employing corona discharge such as corotron and scorotron.

The shape of the charger is determined in accordance with the specification or configuration of the image forming apparatus, and may be in the form of a roller, a magnetic brush, or a fur brush.

The magnetic brush may be composed of various ferrite particles (e.g., Zn-Cu ferrite) serving as the charger, a non-magnetic conductive sleeve for supporting the charger, and a magnet roll contained inside the conductive sleeve.

The fur brush may be made of a fur having been subjected to a conductive treatment with carbon, copper sulfide, a metal, or a metal oxide. Such a fur is wound around or attached to a cored bar having been subjected to a conductive treatment with a metal or the like to be formed into the charger.

The charger is not limited to the contact charger. However, the contact charger is preferred because the amount of by-product ozone is small.

Preferably, the charger is disposed in or out of contact with the image bearer and capable of charging the surface of the image bearer by applying direct-current and alternating-current voltages in superimposition thereto.

Preferably, the charger is a charging roller disposed close to but out of contact with the image bearer via a gap tape and capable of charging the surface of the image bearer by applying direct-current and alternating-current voltages in superimposition thereto.

The irradiation process is a process of irradiating the charged surface of the image bearer with light, and is performed by the irradiator. The irradiation process may be performed by irradiating the surface of the image bearer with light containing image information by the irradiator.

The optical system in the irradiator is roughly divided into an analog optical system and a digital optical system.

The analog optical system directly projects an original document onto the surface of the image bearer.

The digital optical system receives image information as an electric signal, converts the electric signal into an optical signal, and irradiates the image bearer with the optical signal to form an image.

The irradiator is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of irradiating the charged image bearer with light to form an electrostatic latent image. Specific examples thereof include, but are not limited to, various irradiators of radiation optical system type, rod lens array type, laser optical type, liquid crystal shutter optical type, and light emitting diode (LED) optical type.

The irradiation can also be conducted by irradiating the back surface of the image bearer with light containing image information.

The developing process is a process of developing the electrostatic latent image into a toner image, and is performed by the developing device.

The developing device is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of developing the electrostatic latent image into a toner image. Examples thereof include those containing toner and capable of applying the toner to the electrostatic latent image in a contact or non-contact manner.

The developing device may be of either a dry developing type or a wet developing type. The developing device may be either a monochrome developing device or a multicolor developing device. For example, the developing device may include a stirrer that frictionally stirs and charges the toner and a rotatable magnet roller.

In the developing device, toner particles and carrier particles are mixed and stirred. The toner particles are charged by friction and retained on the surface of the rotating magnet roller, thus forming magnetic brush.

The magnet roller is disposed proximity to the image bearer, so that a part of the toner particles composing the magnetic brush formed on the surface of the magnet roller are moved to the surface of the image bearer by an electric attractive force of the electrostatic latent image. As a result, the electrostatic latent image is developed with the toner to form the toner image on the surface of the image bearer.

The toner contained in the developing device may be a developer containing the toner, and the developer may be either a one-component developer or a two-component developer.

The toner may be either a magnetic toner used as a one-component developer without using a carrier, or a non-magnetic toner.

The transfer process is a process of transferring the toner image onto a recording medium, and is performed by the transfer device.

The transfer process preferably includes: a primary transfer process of transferring the toner image onto a surface of an intermediate transferor to form a composite transfer image; and a secondary transfer process of transferring the composite transfer image onto a recording medium.

The transfer device is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of transferring the toner image onto a recording medium. Preferably, the transfer device includes: a primary transfer device that transfers the toner image onto a surface of an intermediate transferor to form a composite transfer image; and a secondary transfer device that transfers the composite transfer image onto a recording medium.

The primary transfer device and the secondary transfer device each preferably include a transferrer that separates the toner image formed on the image bearer toward the recording medium by charging.

The transferrer is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, a corona transferrer utilizing corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transferrer. The number of the transferrers is at least one, and may be two or more.

The recording medium is not particularly limited and can be suitably selected to suit to a particular application as long as an unfixed toner image can be transferred thereon. Specific examples thereof include, but are not limited to, plain paper and polyethylene terephthalate (PET) sheets for overhead projectors (OHP).

The fixing process is a process of fixing the transferred toner image on the recording medium, and is performed by the fixing device. In a case in which toners of two or more colors are used, the toner of each color may be fixed each time the toner is transferred onto the recording medium, or the toners of all colors may be fixed at once after being transferred and stacked on the recording medium.

The fixing device is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of fixing the transferred toner image on the recording medium. The fixing device may employ a thermal fixing method using a known heat-pressure assembly.

The heat-pressure assembly is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, a combination of a heat roller and a pressure roller, and a combination of a heat roller, a pressure roller, and an endless belt.

The heating temperature is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM> to <NUM>. The fixing device may be used together with an optical fixer as necessary.

The cleaning process is a process of removing the toner remaining on the surface of the image bearer, and is performed by the cleaning device.

The cleaning device includes the cleaning blade according to an embodiment of the present invention.

The linear pressure applied to the surface of the image bearer by the blade substrate of the cleaning blade is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM> to <NUM> N/m, and more preferably from <NUM> to <NUM> N/m. When the linear pressure is from <NUM> to <NUM> N/m, defective cleaning in which the toner slips through between the contact part and the rotating body is less likely to occur, and the elastic body is prevented from being turned up.

The linear pressure can be measured using, for example, a measuring apparatus incorporating a small compression load cell available from KYOWA ELECTRONIC INSTRUMENTS CO.

An angle ("cleaning angle") formed between a tangent line of the image bearer at a position that comes into contact with the contact part of the blade substrate of the cleaning blade and the tip surface of the free end of the blade substrate is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM>° to <NUM>°.

When the cleaning angle is from <NUM>° to <NUM>°, the blade substrate can be prevented from being turned up and the occurrence of defective cleaning can be reduced.

The lubricant applying process is a process of applying a lubricant to the surface of the image bearer, and is performed by a lubricant applying device.

The application of the lubricant can be performed by molding the lubricant into a solid shape, pressing the solid lubricant against a fur brush using a pressure spring, rotating the fur brush to apply the lubricant to the surface of the image bearer, and then uniformly applying the lubricant using a lubricant leveling blade.

The lubricant applying device contains the lubricant leveling blade of the present embodiment.

The linear pressure applied to the surface of the image bearer by the blade substrate of the lubricant leveling blade is not particularly limited and can be suitably selected to suit to a particular application, but is preferably from <NUM> to <NUM> N/m, and more preferably from <NUM> to <NUM> N/m. When the linear pressure is from <NUM> to <NUM> N/m, the performance of applying the lubricant to the image bearer is stabilized, and the tip edge portion is prevented from being pulled in.

Preferably, the tip edge portion of the lubricant leveling blade has an angle θ of from <NUM>° to <NUM>°. When the angle θ of the tip edge portion is an obtuse angle within the above-described range, the lubricant leveling blade tip surface 104a is prevented from being pulled in, and application of the lubricant is stabilized. When the angle θ of the tip edge portion of the lubricant leveling blade is <NUM>° or less, the effect of the edge becomes clear, and the lubricant application function is improved.

As illustrated in <FIG>, the angle θ of the tip edge portion is an angle of a blade corner formed by two surfaces facing the surface of the image bearer on an upstream side and a downstream side, respectively, of the lubricant leveling blade tip edge portion 104c in the direction of surface movement of the image bearer.

The other processes may include, for example, a neutralization process, a recycle process, and a control process.

The other devices may include, for example, a neutralizer, a recycler, and a controller.

The neutralization process is a process of applying a neutralization bias voltage to the image bearer to remove charge, and is performed by the neutralizer.

The neutralizer is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of applying a neutralization bias voltage to the image bearer. Specific examples of the neutralizer include, but are not limited to, a neutralization lamp.

The recycle process is a process of recycling the toner removed in the cleaning process for the developing device, and is performed by the recycler.

The recycler is not particularly limited and can be suitably selected to suit to a particular application. Specific examples thereof include, but are not limited to, a conveyor.

The control process is a process of controlling each of the processes, and is performed by the controller.

The controller is not particularly limited and can be suitably selected to suit to a particular application as long as it is capable of controlling each of the devices. Specific examples thereof include, but are not limited to, a sequencer and a computer.

An image forming apparatus according to an embodiment of the present invention is described below with reference to the drawings. The applications of the cleaning blade are provided herein for the purpose of illustration only and are not intended to be limiting.

<FIG> is a schematic diagram illustrating an image forming apparatus <NUM> according to an embodiment of the present invention. The image forming apparatus <NUM> includes four image forming units 1Y, <NUM>, 1C, and <NUM> for forming yellow, magenta, cyan, and black ("Y, M, C, and K") images, respectively. The image forming units 1Y, <NUM>, 1C, and <NUM> have the same configuration except for accommodating different color toners, i.e., yellow, magenta, cyan, and black toners, respectively, as image forming materials.

Above the four image forming units 1Y, 1C, <NUM>, and <NUM> (hereinafter collectively "image forming units <NUM>"), a transfer unit <NUM> is disposed. The transfer unit <NUM> includes an intermediate transfer belt <NUM> as an intermediate transferor. The image forming units 1Y, <NUM>, 1C, and <NUM> include respective photoconductors 3Y, <NUM>, 3C, and <NUM> on which toner images with respective colors are to be formed. The toner images are superimposed on one another on a surface of the intermediate transfer belt <NUM>.

Below the four image forming units <NUM>, an optical writing unit <NUM> is disposed. The optical writing unit <NUM>, serving as a latent image forming device, emits laser light L based on image information to the photoconductors 3Y, <NUM>, 3C, and <NUM> in the respective image forming units 1Y, <NUM>, 1C, and <NUM>. Thus, electrostatic latent images for yellow, magenta, cyan, and black images are formed on the respective photoconductors 3Y, <NUM>, 3C, and <NUM>. In the optical writing unit <NUM>, the laser light L is emitted from a light source, deflected by a polygon mirror <NUM> that is rotary-driven by a motor, and directed to the photoconductors 3Y, <NUM>, 3C, and <NUM> through multiple optical lenses and mirrors. Alternatively, the optical writing unit <NUM> can be replaced with another unit in which a light emitting diode (LED) array performs optical scanning.

Below the optical writing unit <NUM>, a first sheet feeding cassette <NUM> and a second sheet feeding cassette <NUM> are disposed so as to overlap each other in the vertical direction. In each sheet feeding cassette, multiple recording media P are stacked on top of another. The top one of the recording media P in each sheet feeding cassette is in contact with a first sheet feeding roller 151a or a second sheet feeding roller 152a. As the first sheet feeding roller 151a is rotary-driven counterclockwise in <FIG> by a driver, the top one of the recording media P in the first sheet feeding cassette <NUM> is fed to a sheet feeding path <NUM> that is vertically extended on a right side of the sheet feeding cassettes in <FIG>. As the second sheet feeding roller 152a is rotary-driven counterclockwise in <FIG> by a driver, the top one of the recording media P in the second sheet feeding cassette <NUM> is fed to the sheet feeding path <NUM>.

On the sheet feeding path <NUM>, multiple conveyance roller pairs <NUM> are disposed. The recording medium P fed to the sheet feeding path <NUM> is conveyed upward in <FIG> inside the sheet feeding path <NUM> while being nipped by the rollers of the conveyance roller pairs <NUM>.

On a downstream end of the sheet feeding path <NUM> relative to the direction of conveyance of the recording medium P, a registration roller pair <NUM> is disposed. The rollers of the registration roller pair <NUM> nip the recording medium P fed by the conveyance roller pairs <NUM> and stop rotating immediately thereafter. The registration roller pair <NUM> then timely feeds the recording medium P to a secondary transfer nip (to be described later).

<FIG> is a schematic diagram illustrating one of the four image forming units <NUM>.

As illustrated in <FIG>, each of the image forming units <NUM> includes a drum-shaped photoconductor <NUM> serving as an image bearer. The photoconductor <NUM> is in the shape of a drum but may also be in the shape of a sheet or an endless belt.

Around the photoconductor <NUM>, a charging roller <NUM>, a developing device <NUM>, a cleaning device <NUM>, a primary transfer roller <NUM>, a lubricant applying device <NUM>, and a neutralization lamp are disposed. The charging roller <NUM> is a charging member of the charger. The developing device <NUM> develops a latent image formed on a surface of the photoconductor <NUM> into a toner image.

The cleaning device <NUM> removes residual toner particles remaining on the photoconductor <NUM> after the toner image has been transferred therefrom onto the intermediate transfer belt <NUM>. The primary transfer roller <NUM> is a primary transfer member of the primary transfer device that transfers the toner image from the surface of the photoconductor <NUM> onto the intermediate transfer belt <NUM>. The lubricant applying device <NUM> applies a lubricant to the surface of the photoconductor <NUM> having been cleaned by the cleaning device <NUM>. The neutralization lamp is the neutralizer that neutralizes the surface potential of the photoconductor <NUM> having been cleaned.

The charging roller <NUM> is disposed at a predetermined distance from the photoconductor <NUM> without contacting the photoconductor <NUM>. The charging roller <NUM> charges the photoconductor <NUM> to a predetermined potential with a predetermined polarity. After the charging roller <NUM> has uniformly charged the surface of the photoconductor <NUM>, the optical writing unit <NUM> emits the laser light L to the charged surface of the photoconductor <NUM> based on image information to form an electrostatic latent image.

The developing device <NUM> includes a developing roller <NUM> serving as a developer bearer. The developing roller <NUM> is to be applied with a developing bias from a power source. Within the casing of the developing device <NUM>, a supply screw <NUM> and a stirring screw <NUM> are provided for stirring the developer contained in the casing while conveying the developer in opposite directions. Also, a doctor <NUM> for regulating the developer carried on the developing roller <NUM> is disposed within the casing. As the developer is stirred and conveyed by the supply screw <NUM> and the stirring screw <NUM>, toner particles in the developer are charged to have a predetermined polarity. The developer is then carried on the surface of the developing roller <NUM> and regulated by the doctor <NUM>. Toner particles in the developer adhere to a latent image formed on the photoconductor <NUM> at a developing region where the developing roller <NUM> faces the photoconductor <NUM>.

The cleaning device <NUM> includes a fur brush <NUM> and the cleaning blade <NUM>. The cleaning blade <NUM> is in contact with the photoconductor <NUM> so as to face in the direction of movement of the surface of the photoconductor <NUM>. Details of the cleaning blade <NUM> are as described above. The lubricant applying device <NUM> includes a solid lubricant <NUM>, a lubricant pressing spring 103a, and the lubricant leveling blade <NUM>. The fur brush <NUM> serves as an application brush that applies the solid lubricant <NUM> to the photoconductor <NUM>. The solid lubricant <NUM> is held by a bracket 103b and pressed toward the fur brush <NUM> by the lubricant pressing spring 103a. As the fur brush <NUM> rotates so as to trail the rotation of the photoconductor <NUM>, the solid lubricant <NUM> is scraped by the fur brush <NUM> and the scraped-off lubricant is applied to the photoconductor <NUM> by the lubricant leveling blade <NUM>. As the lubricant is applied to the photoconductor <NUM>, the coefficient of friction of the surface of the photoconductor <NUM> is maintained at <NUM> or less during non-image forming periods. The details of the lubricant leveling blade are as described above.

The charger employs a non-contact proximity arrangement system in which the charging roller <NUM> is disposed in proximity to the photoconductor <NUM> without contacting the photoconductor <NUM>. Alternatively, any known charger such as a corotron, a scorotron, and a solid state charger can also be used as the charger. Among these charging systems, contact charging systems and non-contact proximity arrangement systems are preferred, since they have advantages in terms of high charging efficiency, less generation of ozone, and compact size.

Examples of the light source of the optical writing unit <NUM> that emits the laser light L and the light source of the neutralization lamp include all luminous matters such as fluorescent lamp, tungsten lamp, halogen lamp, mercury lamp, sodium-vapor lamp, light-emitting diode (LED), laser diode (LD), and electroluminescence (EL).

For the purpose of emitting only light having a desired wavelength, any type of filter can be used, such as sharp cut filter, band pass filter, near infrared cut filter, dichroic filter, interference filter, and color-temperature conversion filter.

Among these light sources, light-emitting diode and semiconductor laser are preferred since they can emit long-wavelength light (<NUM>-<NUM>) with high energy.

Referring to <FIG>, the transfer unit <NUM> serving as the transfer device further includes, in addition to the intermediate transfer belt <NUM>, a belt cleaning unit <NUM>, a first bracket <NUM>, and a second bracket <NUM>. The transfer unit <NUM> further includes four primary transfer rollers 7Y, <NUM>, 7C, and <NUM>, a secondary transfer backup roller <NUM>, a driving roller <NUM>, an auxiliary roller <NUM>, and a tension roller <NUM>. The intermediate transfer belt <NUM> is stretched taut with these eight rollers and is rotary-driven by the driving roller <NUM> to endlessly move counterclockwise in <FIG>. The four primary transfer rollers 7Y, <NUM>, 7C, and <NUM> and the respective photoconductors 3Y, <NUM>, 3C, and <NUM> are sandwiching the intermediate transfer belt <NUM> that is endlessly moved, forming respective primary transfer nips therebetween. The back surface (i.e., inner circumferential surface of the loop) of the intermediate transfer belt <NUM> is then applied with a transfer bias having the opposite polarity to the toner (e.g., positive polarity). As the intermediate transfer belt <NUM> endlessly moves while sequentially passing the primary transfer nips of yellow, magenta, cyan, and black, the toner images of yellow, magenta, cyan, and black formed on the respective photoconductors 3Y, <NUM>, 3C, and <NUM> are superimposed on one another on the outer circumferential surface of the intermediate transfer belt <NUM>. Thus, a composite toner image in which four color toner images are superimposed on one another is formed on the intermediate transfer belt <NUM>.

The secondary transfer backup roller <NUM> and a secondary transfer roller <NUM>, disposed outside the loop of the intermediate transfer belt <NUM>, are sandwiching the intermediate transfer belt <NUM> to form a secondary transfer nip therebetween. The above-described registration roller pair <NUM> feeds the recording medium P to the secondary transfer nip in synchronization with an entry of the composite toner image on the intermediate transfer belt <NUM> into the secondary transfer nip. The composite toner image on the intermediate transfer belt <NUM> is secondarily transferred onto the recording medium P in the secondary transfer nip by the actions of a secondary transfer electric field and the nip pressure. The secondary transfer electric field is formed between the secondary transfer roller <NUM> to which a secondary transfer bias is applied and the secondary transfer backup roller <NUM>. The composite toner image is combined with the white color of the recording medium P to become a full-color toner image.

On the intermediate transfer belt <NUM> having passed through the secondary transfer nip, residual toner particles that have not been transferred onto the recording medium P are remaining. These residual toner particles are removed by the belt cleaning unit <NUM>. The belt cleaning unit <NUM> includes a belt cleaning blade 162a in contact with the outer circumferential surface of the intermediate transfer belt <NUM>. The belt cleaning blade 162a scrapes off the residual toner particles from the intermediate transfer belt <NUM>.

The first bracket <NUM> of the transfer unit <NUM> is swingable about the rotation axis of the auxiliary roller <NUM> at a predetermined angle in accordance with on/off driving operation of a solenoid. When the image forming apparatus <NUM> is to form a black-and-white image, the first bracket <NUM> is slightly rotated counterclockwise in <FIG> by driving the solenoid. This rotation of the first bracket <NUM> makes the primary transfer rollers 7Y, <NUM>, and 7C revolve counterclockwise in <FIG> about the rotation axis of the auxiliary roller <NUM> to bring the intermediate transfer belt <NUM> away from the photoconductors 3Y, <NUM>, and 3C. Thus, among the four image forming units 1Y, <NUM>, 1C, and <NUM>, only the image forming unit <NUM> for black image is brought into operation to form a black-and-white image. Since unnecessary driving of the image forming units 1Y, <NUM>, and 1C is avoid during formation of the black-and-white image, undesired deterioration of compositional members of the image forming units 1Y, <NUM>, and 1C can be prevented.

Above the secondary transfer nip in <FIG>, a fixing unit <NUM> is disposed. The fixing unit <NUM> includes a pressure heating roller <NUM> and a fixing belt unit <NUM>. The pressure heating roller <NUM> contains a heat source, such as a halogen lamp, inside. The fixing belt unit <NUM> includes a fixing belt <NUM> serving as a fixing member, a heating roller <NUM> containing a heat source (e.g., halogen lamp) inside, a tension roller <NUM>, a driving roller <NUM>, and a temperature sensor. The fixing belt <NUM> in an endless-belt form is stretched taut with the heating roller <NUM>, the tension roller <NUM>, and the driving roller <NUM>, and is endlessly moved counterclockwise in <FIG>. The fixing belt <NUM> is heated from its back surface side by the heating roller <NUM> while endlessly moving. At a position where the fixing belt <NUM> is wound around the heating roller <NUM>, the pressure heating roller <NUM> is contacting the outer circumferential surface of the fixing belt <NUM>.

The pressure heating roller <NUM> is driven to rotate clockwise in <FIG>. Thus, the pressure heating roller <NUM> and the fixing belt <NUM> form a fixing nip therebetween.

The temperature sensor is disposed outside the loop of the fixing belt <NUM> facing the outer circumferential surface of the fixing belt <NUM> forming a predetermined gap therebetween. The temperature sensor detects the surface temperature of the fixing belt <NUM> immediately before entering into the fixing nip. The detection result is transmitted to a fixing power supply circuit. The fixing power supply circuit on/off controls power supply to the heat sources contained in the heating roller <NUM> and the pressure heating roller <NUM> based on the detection result.

The recording medium P having passed though the secondary transfer nip is then separated from the intermediate transfer belt <NUM> and fed to the fixing unit <NUM>. The recording medium P is fed upward in <FIG> while being sandwiched by the fixing nip in the fixing unit <NUM>. During this process, the recording medium P is heated and pressurized by the fixing belt <NUM>, and the full-color toner image is fixed on the recording medium P.

The recording medium P having the fixed image thereon is passed through an ejection roller pair <NUM> and ejected outside the image forming apparatus <NUM>. On the top surface of the housing of the image forming apparatus <NUM>, a stack part <NUM> is formed. The recording media P ejected by the ejection roller pair <NUM> are successively stacked on the stack part <NUM>.

Above the transfer unit <NUM>, four toner cartridges 100Y, <NUM>, 100C, and <NUM> accommodating yellow toner, magenta toner, cyan toner, and black toner, respectively, are disposed. The yellow, magenta, cyan, and black toners accommodated in the respective toner cartridges 100Y, <NUM>, 100C, and <NUM> are supplied to the respective developing devices 5Y, <NUM>, 5C, and <NUM> in the respective image forming units 1Y, <NUM>, 1C, and <NUM>. The toner cartridges 100Y, <NUM>, 100C, and <NUM> are detachably mountable on the image forming apparatus main body independent from the image forming units 1Y, <NUM>, 1C, and <NUM>.

Next, an image forming operation of the image forming apparatus <NUM> is described below.

In response to receipt of a print execution signal from an operation panel, the charging roller <NUM> and the developing roller <NUM> each get applied with a predetermined voltage or current at a predetermined timing. Similarly, the light sources in the optical writing unit <NUM> and the neutralization lamp each get applied with a predetermined voltage or current at a predetermined timing. In synchronization with the application of voltage or current, the photoconductor <NUM> is driven to rotate in a direction indicated by arrow in <FIG> by a photoconductor driving motor.

As the photoconductor <NUM> rotates in a direction indicated by arrow in <FIG>, the surface of the photoconductor <NUM> is uniformly charged to a predetermined potential by the charging roller <NUM>. The optical writing unit <NUM> emits the laser light L to the charged surface of the photoconductor <NUM> based on image information. A part of the surface of the photoconductor <NUM> irradiated with the laser light L is neutralized, thereby forming an electrostatic latent image. The surface of the photoconductor <NUM> having the electrostatic latent image thereon is rubbed by a magnetic brush formed of the developer on the developing roller <NUM> at a position where the photoconductor <NUM> is facing the developing device <NUM>. As a developing bias is applied to the developing roller <NUM>, negatively-charged toner particles on the developing roller <NUM> are transferred onto the electrostatic latent image, thus forming a toner image. This image forming process is performed in each of the image forming units 1Y, <NUM>, 1C, and <NUM> to form yellow, magenta, cyan, and black toner images on the photoconductors 3Y, <NUM>, 3C, and <NUM>, respectively.

Thus, in the image forming apparatus <NUM>, the developing device <NUM> develops the electrostatic latent image formed on the photoconductor <NUM> with negatively-charged toner particles based on reversal development. In the present embodiment, an N/P (i.e., negative/positive) development system (in which toner particles get adhered to low-potential regions) and a non-contact charging roller are employed, but the development and charging systems are not limited thereto.

The toner images formed on the photoconductors 3Y, <NUM>, 3C, and <NUM> are primarily transferred onto the surface of the intermediate transfer belt <NUM> in a sequential manner so that they get superimposed on one another on the surface of the intermediate transfer belt <NUM>. Thus, a composite toner image is formed on the intermediate transfer belt <NUM>.

The composite toner image ("toner image" for simplicity) formed on the intermediate transfer belt <NUM> is transferred onto the recording medium P which has been fed from the first sheet feeding cassette <NUM> or second sheet feeding cassette <NUM>, passed through the registration roller pair <NUM>, and fed to the secondary transfer nip. The recording medium P is once stopped by being sandwiched by the registration roller pair <NUM>, and then fed to the secondary transfer nip in synchronization with an entry of the leading end of the toner image on the intermediate transfer belt <NUM> into the secondary transfer nip. The recording medium P having the transferred toner image thereon is then separated from the intermediate transfer belt <NUM> and fed to the fixing unit <NUM>. As the recording medium P having the transferred toner image thereon passes through the fixing unit <NUM>, the toner image is fixed on the transfer sheet P by heat and pressure. The transfer sheet P having the fixed toner image thereon is ejected outside the image forming apparatus <NUM> and stacked at the stack part <NUM>.

On the other hand, after the toner image has been transferred from the surface of the intermediate transfer belt <NUM> onto the recording medium P in the secondary transfer nip, the belt cleaning unit <NUM> removes residual toner particles remaining on the surface of the intermediate transfer belt <NUM>.

Similarly, after the toner image has been transferred from the surface of the photoconductor <NUM> onto the intermediate transfer belt <NUM> in the primary transfer nip, the cleaning device <NUM> removes residual toner particles remaining on the surface of the photoconductor <NUM>. The lubricant applying device <NUM> then applies a lubricant to the cleaned surface, and the neutralization lamp further neutralizes the surface.

As illustrated in <FIG>, each of the image forming units <NUM> of the image forming apparatus <NUM> has a frame body <NUM> accommodating the photoconductor <NUM> and the processing devices including the charging roller <NUM>, the developing device <NUM>, the cleaning device <NUM>, and the lubricant applying device <NUM>. The image forming units <NUM> is temporarily detachable from the main body of the image forming apparatus <NUM> as a process cartridge. Thus, in the image forming apparatus <NUM>, the photoconductor <NUM> and the processing devices are replaceable at the same time by replacing each of the image forming units <NUM> as the process cartridge. Alternatively, each of the photoconductor <NUM>, the charging roller <NUM>, the developing device <NUM>, the cleaning device <NUM>, and the lubricant applying device <NUM> may be independently replaceable.

A process cartridge of the present embodiment includes: an image bearer; at least one of a charger, an irradiator, a developing device, and a transfer device; and a cleaning device that comes into contact with the surface of the image bearer to remove a residue on the surface of the image bearer. The process cartridge may further include other devices such as a lubricant applying device that comes into contact with the surface of the image bearer to apply a lubricant to the surface of the image bearer.

The lubricant applying device includes the lubricant leveling blade according to an embodiment of the present invention.

The process cartridge is a device (part) that is detachably mountable on an image forming apparatus, which contains: an image bearer; at least one of a charger, an irradiator, a developing device, and a transfer device; and a cleaning device, and optionally a lubricant applying device.

Hereinafter, the present invention will be further described by way of examples and reference examples, but the present invention is not limited to the following examples. In the following descriptions, "parts" represents "parts by mass" unless otherwise specified.

Polyurethane elastomer sheets obtained through the processes of centrifugal molding, curing, and post-crosslinking were respectively used for the edge layer and the base layer. The average thickness and Martens hardness (HM) of the edge layer and the base layer are as follows.

The edge layer and the base layer were bonded to each other to prepare a blade substrate. The blade substrate was bonded to a metal plate.

In a screw tube, <NUM> parts of a polytetrafluoroethylene (PTFE) micropowder (TF9201Z, product of <NUM> Company, having a volume average particle diameter of <NUM>) as the first fluorine-based resin, <NUM> parts of a VdF-HFP-TFE terpolymer composed of vinylidene fluoride (VdF), hexafluoropropylene (HFP), and tetrafluoroethylene (TFE) as the second fluorine-based resin, and <NUM> parts of <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoroethyl <NUM>,<NUM>,<NUM>-trifluoroethyl ether (HFE-<NUM>, product of Tokyo Chemical Industry Co. ) as a fluorine-based dispersion medium were put and stirred using a stirrer. Thus, a particle dispersion A was prepared.

In a screw tube, <NUM> parts of a polytetrafluoroethylene (PTFE) micropowder (TF9201Z, product of <NUM> Company, having a volume average particle diameter of <NUM>) as the first fluorine-based resin, <NUM> parts of polyvinylidene fluoride (PVdF) as the second fluorine-based resin, and <NUM> parts of <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoroethyl <NUM>,<NUM>,<NUM>-trifluoroethyl ether (HFE-<NUM>, product of Tokyo Chemical Industry Co. ) as a fluorine-based dispersion medium were put and stirred using a stirrer. Thus, a particle dispersion B was prepared.

In a screw tube, <NUM> parts of a polytetrafluoroethylene (PTFE) micropowder (TF9201Z, product of <NUM> Company, having a volume average particle diameter of <NUM>) as the first fluorine-based resin, <NUM> parts of a VdF-HFP copolymer composed of vinylidene fluoride (VdF) and hexafluoropropylene (HFP) as the second fluorine-based resin, and <NUM> parts of <NUM>,<NUM>,<NUM>,<NUM>-tetrafluoroethyl <NUM>,<NUM>,<NUM>-trifluoroethyl ether (HFE-<NUM>, product of Tokyo Chemical Industry Co. ) as a fluorine-based dispersion medium were put and stirred using a stirrer. Thus, a particle dispersion C was prepared.

In a screw tube, <NUM> parts of an aqueous dispersion of polymethyl methacrylate (PMMA) (MX100W, product of NIPPON SHOKUBAI CO. , having a volume average particle diameter of <NUM>) and <NUM> parts of polyvinyl butyral (PVB) (S-LEC KW-M, product of SEKISUI CHEMICAL CO. , having a degree of acetalization of <NUM>±<NUM> mol%) as the second fluorine-based resin were stirred using a stirrer. Thus, a particle dispersion D was prepared.

One end surface of the peripheral side surfaces of the cleaning blade (hereinafter, may be referred to as a "cleaning blade tip surface") was dipped in the particle dispersion A at a right angle to a horizontal plane by a depth of <NUM> from the cleaning blade tip surface, and pulled up at a pulling rate of <NUM>/s. For the purpose of collecting the PTFE particles that impart the cleaning function in a portion including the contact edge of the cleaning blade tip surface, the cleaning blade was tilted by about <NUM>°, as illustrated in <FIG>, and dried at room temperature (<NUM>) for <NUM> minutes. Thus, a cleaning blade of Example <NUM> was prepared.

Cleaning blades of Examples <NUM> to <NUM> were prepared in the same manner as in Example <NUM> except that the Martens hardness of the edge layer, the Martens hardness of the base layer, and the average thickness of the coating layer in the cleaning blades were changed as presented in Tables <NUM> to <NUM>.

Cleaning blades of Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> were prepared in the same manner as in Example <NUM> except that the first fluorine-based resin, the second fluorine-based resin, the dispersion medium, the Martens hardness of the edge layer, the Martens hardness of the base layer, and the average thickness of the coating layer in the cleaning blades were changed as presented in Tables <NUM> to <NUM>.

In Example <NUM>, Example <NUM>, and Comparative Example <NUM>, the particle dispersion B, the particle dispersion C, and the particle dispersion D were used, respectively.

The cleaning blade of Comparative Example <NUM> includes a blade substrate provided with no coating layer.

Each of the cleaning blades obtained in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> was mounted on a process cartridge of a color multifunction peripheral (IMAGIO MP C4500, product of Ricoh Co. ), the printer part of which having the same configuration as the image forming apparatus <NUM> illustrated in <FIG>, to assemble an image forming apparatus. The cleaning blade was mounted on the image forming apparatus so as to exhibit a linear pressure of <NUM>/cm and a cleaning angle of <NUM>°.

The Martens hardness of the edge layer and the Martens hardness of the base layer of each of the cleaning blades obtained in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> were measured.

The Martens hardness (HM) can be measured according to ISO <NUM> using a nanoindenter (ENT-<NUM>, product of ELIONIX INC. ) by pushing a Berkovich indenter into a sample with a load of <NUM>,<NUM>µN for <NUM> seconds, holding for <NUM> seconds, and pulling the indenter with the same loading rate for <NUM> seconds. The results are presented in Tables <NUM> to <NUM>.

The Martens hardness of the edge layer was measured at a position <NUM> distant from the tip edge portion of the edge layer. The Martens hardness of the base layer was measured at a position <NUM> distant from the tip edge portion of the base layer.

The Martens hardness is the median of the values measured at <NUM> to <NUM> positions.

The average thickness of the coating layer of each of the cleaning blades obtained in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> was measured. The results are presented in Tables <NUM> to <NUM>.

The average thickness was measured by scraping off a part of the coating layer with a spatula, a cotton swab, or the like and measuring the shape thereof using a contact surface roughness meter (SURFTEST SJ-<NUM>, product of Mitutoyo Corporation).

The above-prepared imaging apparatus was made to produce output under the following conditions to measure the rate of change in the driving torque increase of the photoconductor. After the output, the tip portion of the cleaning blade was observed with a laser microscope (LEXT OLS4500, product of Olympus Corporation), and the torque increase rate was evaluated based on the following criteria. The evaluation results are presented in Tables <NUM> to <NUM>. The "initial value" defined in the evaluation criteria refers to the value obtained in the initial stage in which the 1st to 500th sheets were output.

The above-prepared image forming apparatus was made to produce output under the following conditions. After that, the tip portion of the cleaning blade and the surface of the photoconductor were observed with a laser microscope (LEXT OLS4500, product of Olympus Corporation) and evaluated based on the following criteria. The evaluation results are presented in Tables <NUM> to <NUM>.

A lubricant leveling blade of Reference Example <NUM> was prepared in the same manner as in Example <NUM> except that the average thickness was changed to <NUM>.

Lubricant leveling blades of Reference Examples <NUM> to <NUM> were prepared in the same manner as in Reference Example <NUM> except that the Martens hardness of the edge layer, the Martens hardness of the base layer, and the average thickness of the coating layer in the lubricant leveling blades were changed as presented in Tables <NUM> to <NUM>.

Lubricant leveling blades of Reference Examples <NUM> and <NUM> and Reference Comparative Examples <NUM> to <NUM> were prepared in the same manner as in Reference Example <NUM> except that the first fluorine-based resin, the second fluorine-based resin, the dispersion medium, the Martens hardness of the edge layer, the Martens hardness of the base layer, and the average thickness of the coating layer in the lubricant leveling blades were changed as presented in Tables <NUM> to <NUM>.

In Reference Example <NUM>, Reference Example <NUM>, and Reference Comparative Example <NUM>, the particle dispersion B, the particle dispersion C, and the particle dispersion D were used, respectively.

The lubricant leveling blade of Reference Comparative Example <NUM> includes a blade substrate provided with no coating layer.

An image forming apparatus was assembled in the same manner as in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>. Each of the lubricant leveling blades of Reference Examples <NUM> to <NUM> and Reference Comparative Examples <NUM> to <NUM> was attached to the image forming apparatus so as to exhibit a linear pressure of <NUM>/cm and an angle θ of the tip edge portion of from <NUM>° to <NUM>°.

The Martens hardness of the edge layer and the Martens hardness of the base layer of the lubricant leveling blades obtained in Reference Examples <NUM> to <NUM> and Reference Comparative Examples <NUM> to <NUM> were measured in the same manner as in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>. The results are presented in Tables <NUM> to <NUM>.

The average thickness of the coating layer of each of the lubricant leveling blades obtained in Reference Examples <NUM> to <NUM> and Reference Comparative Examples <NUM> to <NUM> was measured in the same manner as in Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>. The results are presented in Tables <NUM> to <NUM>.

The above-prepared image forming apparatuses including the respective lubricant leveling blades obtained in Reference Examples <NUM> to <NUM> and Reference Comparative Examples <NUM> to <NUM> were made to produce output under the following conditions. After that, a halftone image was output, and the degree of unevenness in the longitudinal direction of the photoconductor was evaluated. It is known that the more uniformly the lubricant is applied in the longitudinal direction of the photoconductor, the less the unevenness on the image.

The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings.

Claim 1:
A cleaning blade (<NUM>) for cleaning a rotating body, the cleaning blade (<NUM>) comprising:
an edge layer (622a) having a tip portion that comes into contact with the rotating body; and
a coating layer (<NUM>) on the tip portion of the edge layer,
wherein the coating layer (<NUM>) contains a first fluorine-based resin and a second fluorine-based resin incompatible with the first fluorine-based resin, so that the first fluorine-based resin and the second fluorine-based resin incompletely mix with each other forming interfaces therebetween,
wherein the cleaning blade (<NUM>) has a Martens hardness when measured according to the description of from <NUM> to <NUM> N/mm<NUM> at a position <NUM> distant from a tip edge portion of the edge layer.