JP5621428B2 - Protective layer forming apparatus, image forming method, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to a protective layer forming apparatus, an image forming method, an image forming apparatus, and a process cartridge.

Conventional image forming apparatuses based on electrophotography are uniformly charged while rotating an image carrier (generally a photosensitive member) generally in the form of a drum or a belt, regardless of the development method. A latent image pattern is formed on the image carrier by the method described above, this is visualized by a developing device, and the toner image is transferred onto a transfer medium to form an image.
Further, the toner component that has not been transferred remains on the image carrier after the toner image is transferred onto the transfer medium. If such a residue is conveyed as it is to the charging step, uniform charging of the image carrier may be hindered. For this reason, generally, the toner component remaining on the image carrier after the transfer step is removed in the cleaning step, and the surface of the image carrier is sufficiently cleaned, and then charging is performed.

In each process of image formation, there are various physical stresses and electrical stresses. As a result, there is a problem that the image carrier is contaminated.
In order to solve this problem, proposals have been made on the supply of lubricating components and the film forming method.

For example, using a protective agent supply device having a protective agent block and a brush roller, the protective agent is scraped off from the protective agent block by the rotation of the brush roller, and the shaved protective agent is supplied to the image carrier via the brush roller. A method has been proposed (for example, Patent Document 1).
However, when the protective agent block is scraped off with a brush roller and the protective agent is supplied to the image bearing member as in the proposed technique, the amount of the protective agent scraping greatly decreases with time. In some cases, the toner cannot be stably supplied to the image carrier. This is because the stiffness of the hair of the brush roller is likely to change over time, and the change in stiffness affects the shaving amount of the protective agent.

Therefore, a method has been proposed in which a protective agent block obtained by melt-molding zinc stearate or the like is scraped off by a foam roller and supplied to an image carrier (Patent Document 2).
However, in this proposed technique, since the protective agent block is relatively hard, if the foam roller is pressed against the protective agent block with a practical pressure and the protective agent is scraped off, the amount of cutting is reduced. There is. Further, when the pressure is increased to increase the amount of shaving of the protective agent block, there are problems that the torque is increased and the protective agent block is damaged.

  Accordingly, a protective layer forming apparatus that can suppress contamination of the image carrier and can stably supply a necessary amount of the protective agent to the image carrier over a long period of time even in practical pressing, and the protective layer At present, an image forming method using the forming apparatus, an image forming apparatus, and a process cartridge are required.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention provides a protective layer forming apparatus that can suppress contamination of an image carrier and can stably supply a necessary amount of a protective agent to the image carrier over a long period of time even in practical pressing. Another object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge using the protective layer forming apparatus.

Means for solving the problems are as follows. That is,
<1> A protective agent block formed by compression molding and containing a fatty acid metal salt;
A roller-shaped protective agent supply member having a core material and a foam layer formed on the outer periphery of the core material, the protective agent is scraped off from the protective agent block and supplied to the surface of the image carrier. This is a protective layer forming apparatus.
<2> The protective layer forming apparatus according to <1>, wherein the foam layer is an open-cell foam layer.
<3> The protective layer forming apparatus according to any one of <1> to <2>, wherein the protective agent block further contains an inorganic lubricant.
<4> The protective layer forming apparatus according to any one of <1> to <3>, wherein the foam layer has a cell of 25 / inch to 300 / inch and has a hardness of 50N to 500N. It is.
<5> The protective layer forming apparatus according to any one of <1> to <4>, wherein the fatty acid metal salt is zinc stearate.
<6> The protective layer forming apparatus according to any one of <3> to <5>, wherein the inorganic lubricant is boron nitride.
<7> a pressing force applying member that presses the protective agent block and contacts the protective agent supply member;
The protective layer forming apparatus according to any one of <1> to <6>, further including a protective layer forming member that forms a protective layer by thinning the protective agent supplied to the surface of the image carrier.
<8> an electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A developing step of developing the electrostatic latent image with toner to form a visible image;
A transfer step of transferring the visible image to a recording medium;
A protective layer forming step of forming a protective layer by applying a protective agent to the surface of the image carrier after transfer;
At least a fixing step of fixing the transferred image transferred to the recording medium,
In the image forming method, the protective layer forming step is performed by the protective layer forming apparatus according to any one of <1> to <7>.
<9> an image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the image carrier;
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image to a recording medium;
A protective layer forming means for forming a protective layer by applying a protective agent to the surface of the image carrier after transfer;
And at least fixing means for fixing the transferred image transferred to the recording medium,
An image forming apparatus, wherein the protective layer forming unit is the protective layer forming apparatus according to any one of <1> to <7>.
<10> A process cartridge comprising at least an image carrier and the protective layer forming device according to any one of <1> to <7>, wherein the process cartridge is detachable from a main body of the image forming device. It is.

  According to the present invention, the above-described problems can be solved, contamination of the image carrier can be suppressed, and a necessary amount of protective agent can be stably applied to the image carrier over a long period even in practical pressing. A protective layer forming apparatus that can be supplied, an image forming method using the protective layer forming apparatus, an image forming apparatus, and a process cartridge can be provided.

FIG. 1 is a perspective view showing a process of forming a protective agent block by compression molding using a protective agent block manufacturing apparatus. 2 is a sectional side view of the manufacturing apparatus shown in FIG. FIG. 3 is a diagram showing one embodiment of the shape of the protective agent block. FIG. 4 is a schematic cross-sectional view showing the structure of a closed cell foam layer. FIG. 5 is a schematic cross-sectional view showing the structure of an open-cell foam layer. FIG. 6A is a front view of the protective agent supply member. FIG. 6B is an enlarged view of the foam layer of the protective agent supply member. FIG. 7 is a schematic sectional view showing an example of the protective layer forming apparatus of the present invention. FIG. 8 is a schematic sectional view showing an example of the image forming apparatus of the present invention. FIG. 9 is a schematic sectional view showing an example of the process cartridge of the present invention. FIG. 10 is a graph showing a change in the consumption of the protective agent block in the example. FIG. 11 is a graph showing changes in consumption of the protective agent block in the example. FIG. 12 is a graph showing a change in consumption of the protective agent block in the example. FIG. 13 is a graph showing a change in consumption of the protective agent block in the comparative example.

(Protective layer forming device)
The protective layer forming apparatus of the present invention includes at least a protective agent block and a protective agent supply member, and further includes other members such as a pressing force applying member and a protective layer forming member as necessary.

<Protective agent block>
The protective agent block contains at least a fatty acid metal salt, and further contains other components such as an inorganic lubricant as necessary.
The protective agent block is formed by compression molding.

-Fatty acid metal salt-
The fatty acid metal salt is not particularly limited and may be appropriately selected depending on the purpose.For example, stearic acid metal salt, oleic acid metal salt, palmitic acid metal salt, caprylic acid metal salt, linolenic acid metal salt, Examples include ricinoleic acid metal salts.
Examples of the metal stearate include, for example, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, stearin Examples include zinc acid.
Examples of the metal oleate include zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate and the like.
Examples of the metal palmitate include zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, and the like.
Examples of the caprylic acid metal salt include lead caprylate.
Examples of the linolenic acid metal salt include zinc linolenate, cobalt linolenate, and calcium linolenate.
Examples of the ricinoleic acid metal salt include zinc ricinoleate and cadmium ricinoleate.
Among these, a metal stearate is preferable and zinc stearate is more preferable because it is excellent in suppressing contamination of the image carrier.
These fatty acid metal salts may be used alone or in combination of two or more.

-Inorganic lubricant-
The protective agent block preferably contains an inorganic lubricant from the viewpoint of suppressing contamination of the charging member.
The inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, graphite, etc. Is mentioned.
Among these, boron nitride is preferable because it is superior in suppressing contamination of the charging member.
These inorganic lubricants may be used alone or in combination of two or more.

  There is no restriction | limiting in particular as a mixture ratio of the said fatty acid metal salt and the said inorganic lubricant in the said protective agent block, Although it can select suitably according to the objective, Fatty acid metal salt: Inorganic lubricant (mass ratio) = 100 : 0-50: 50 is preferable, and 90: 10-60: 40 is more preferable. If the fatty acid metal salt is less than 50:50 in the blending ratio, it may be difficult to form a protective layer on the image carrier. When the blending ratio is in the more preferable range, it is advantageous in that it is excellent in suppressing contamination of the image carrier and contamination of the charging member.

There is no restriction | limiting in particular as a magnitude | size and a shape of the said protective agent block, Although it can select suitably according to the objective, As a shape, bar shape is mentioned, for example.
Examples of the bar shape include a quadrangular prism shape and a cylindrical shape.

There is no restriction | limiting in particular as a filling rate of the said protective agent block, Although it can select suitably according to the objective, 80%-98% are preferable in the protective agent block formed by compression molding, and 84%-95% are More preferred. If the filling ratio is less than 80%, the mechanical strength of the protective agent block is low, so cracking may occur during handling of the protective agent block, and if it exceeds 98%, the press at the time of compression molding It is necessary to increase the capacity of the machine, and cracks may occur during molding.
The filling rate can be determined by the ratio of the actual density of the protective agent block and the theoretical density of the mixture before forming the protective agent.
In addition, the filling rate of the protective agent block formed by melt molding is usually 100%.

-Compression molding-
The protective agent block is formed by compression molding.
There is no restriction | limiting in particular as the method of the said compression molding, According to the objective, it can select suitably. Here, an example of the compression molding method will be described with reference to the drawings.
FIG. 1 is a perspective view showing a process of forming a protective agent block by compression molding using a protective agent block manufacturing apparatus. 2 is a sectional side view of the manufacturing apparatus shown in FIG.

  As shown in FIGS. 1 and 2, the protective agent block manufacturing apparatus 50 forms a lower mold 51 and a side surface that is disposed so as to sandwich the lower mold 51 and extends in the longitudinal direction of the protective agent block. A pair of horizontal molds 52, a pair of end molds 53 that are arranged so as to sandwich the lower mold 51 and the horizontal mold 52 and form an end surface in the longitudinal direction of the protective agent block, and an upper mold 54 are provided.

  In FIG. 1, one of the end molds 53 is shown in a disassembled state, but actually occupies a position opposite to the other end mold 53, and at the time of compression molding of the protective agent block described below. The end mold 53, the lower mold 51, and the horizontal mold 52 form a sealed space except for the space into which the upper mold 54 enters. 1 and 2, when the upper mold 54 moves and enters the sealed space, the lower mold 51, the horizontal mold 52, the end mold 53, and the upper mold 54 completely A sealed space is formed.

  With the upper mold 54 removed, the formed space is filled with powder G as a raw material of the protective agent block. The powder G may be granular, granular, or a mixture thereof.

When the introduction of the powder G is completed, the upper die 54 is advanced in the V direction toward the sealed space, and pressing is performed while forming a complete sealed space, whereby the protective agent block is formed.
Through the above steps, a square columnar protective agent block as shown in FIG. 3 is manufactured by compression molding.

  General protective agent blocks include a protective agent block formed by melt molding and a protective agent block formed by compression molding. Since the protective agent block formed by melt molding is translucent and the protective agent block formed by compression molding is white, these can be distinguished by visual observation.

<Protective agent supply member>
The protective agent supply member is a member that removes the protective agent from the protective agent block and supplies the protective agent to the surface of the image carrier.
The protective agent supply member includes at least a core material and a foam layer, and further includes other portions as necessary.
The protective agent supply member has a roller shape.

−Core material−
There is no restriction | limiting in particular as a material of the said core material, a shape, a magnitude | size, and a structure, According to the objective, it can select suitably.
Examples of the material for the core include resin and metal. Examples of the resin include an epoxy resin and a phenol resin. Examples of the metal include iron, aluminum, and stainless steel.
Examples of the shape of the core material include a columnar shape and a cylindrical shape.

-Foam layer-
The foam layer is formed on the outer periphery of the core material.
There is no restriction | limiting in particular as a material of the said foam layer, According to the objective, it can select suitably, For example, a foaming polyurethane is mentioned.

--Foamed polyurethane--
There is no restriction | limiting in particular as said foaming polyurethane, According to the objective, it can select suitably, For example, a polyol, polyisocyanate, a catalyst, and a foaming agent are mixed at least, and also if necessary, foam control Examples thereof include foamed polyurethane obtained by mixing and reacting other components such as an agent.

--- Polyol ---
There is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably, For example, polyether polyol, polyester polyol, etc. are mentioned. Among these, polyether polyol is preferable from the viewpoint of easy adjustment of processability and foam layer hardness.

As the polyether polyol, for example, at least one of a low molecular polyol and a low molecular polyamine having 2 to 8 active hydrogen groups is used as an initiator, and at least one of ethylene oxide and propylene oxide is opened. Examples include polyether polyols obtained by addition polymerization.
Examples of the polyether polyol include polyether polyether polyols, polyester polyether polyols, and polymer polyether polyols that are generally used in the production of flexible polyurethane foams.
The polyether polyol is preferably a polyether polyether polyol in which ethylene oxide is bonded to the terminal at 5 mol% or more from the viewpoint of moldability.

Examples of the polyester polyol include dibasic acids such as adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, and maleic anhydride, and anhydrides thereof, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, di-acid, and the like. Examples thereof include polyester polyols obtained by polymerizing glycols and triols such as propylene glycol, 1,4-butanediol, glycerin, and trimethylolpropane.
Further, as the polyester polyol, those obtained by depolymerizing a waste material of polyethylene terephthalate resin with the above-mentioned glycol can also be used.
The said polyol may be used individually by 1 type, and may use 2 or more types together.

--- Polyisocyanate ---
The polyisocyanate is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 2,4-tolylene diisocyanate (2,4-TDI) and 2,6-tolylene diisocyanate (2,6 -TDI), tolidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI, polymethylene polyphenyl polyisocyanate, polymeric polyisocyanate, etc. Is mentioned.
The said polyisocyanate may be used individually by 1 type, and may use 2 or more types together.

  There is no restriction | limiting in particular as a compounding quantity of the said polyisocyanate, According to the objective, it can select suitably, For example, as equivalent ratio (NCO / OH) of the isocyanate group of the said polyisocyanate with respect to the hydroxyl group of the said polyol, 1. The range of 0-3.0 is mentioned.

---- Catalyst ---
There is no restriction | limiting in particular as said catalyst, According to the objective, it can select suitably, For example, an amine catalyst, an organometallic catalyst, etc. are mentioned.
Examples of the amine catalyst include triethylenediamine, dimethylethanolamine, and bis (dimethylamino) ethyl ether.
Examples of the organometallic catalyst include dioctyltin and distearyltin dibutyrate.
The catalyst may be a reactive catalyst such as dimethylaminoethanol having active hydrogen.
These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as a compounding quantity of the said catalyst, According to the objective, it can select suitably, For example, 0.01 mass part-20 mass parts are mentioned with respect to 100 mass parts of said polyols.

---- Foaming agent ---
There is no restriction | limiting in particular as said foaming agent, According to the objective, it can select suitably, For example, water, a fluorocarbon compound, a low boiling point hydrocarbon type compound etc. are mentioned.
Examples of the fluorocarbon compounds include HCFC-141b, HFC-134a, HFC-245fa, HFC-365mfc, and the like.
Examples of the low-boiling hydrocarbon compound include cyclopentane, n-pentane, iso-pentane, and n-butane.
These foaming agents may be used alone or in combination of two or more.
There is no restriction | limiting in particular as a compounding quantity of the said foaming agent, According to the objective, it can select suitably, For example, 5 mass parts-50 mass parts are mentioned with respect to 100 mass parts of said polyols.

---- Foam stabilizer ---
There is no restriction | limiting in particular as said foam stabilizer, According to the objective, it can select suitably, For example, a silicone type surfactant is mentioned.
Commercially available silicone surfactants include dimethylsiloxane foam stabilizers (for example, “SRX-253” manufactured by Tore Dow Corning Silicone, “F-122” manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. Modified dimethylsiloxane-based foam stabilizer [for example, “L-5309”, “SZ-1311”, etc., manufactured by Nippon Unicar Co., Ltd.] and the like.
There is no restriction | limiting in particular as a compounding quantity of the said foam stabilizer, According to the objective, it can select suitably, For example, 0.2 mass part-10 mass parts are mentioned with respect to 100 mass parts of said polyols.

---- Other ingredients ----
Examples of the other components include cross-linking agents and foam breakers for controlling the formation of closed cells and open cells.
There is no restriction | limiting in particular as said crosslinking agent, According to the objective, it can select suitably, For example, a triethanolamine, a diethanolamine, etc. are mentioned.
There is no restriction | limiting in particular as said foam breaker, According to the objective, it can select suitably, For example, the thing with high foam breakability is mentioned in the said foam stabilizer.

  When producing the polyurethane foam, a method is generally used in which raw materials for the polyurethane foam other than the polyisocyanate are mixed in advance, and the mixture and the polyisocyanate are mixed immediately before molding.

  There is no restriction | limiting in particular as a shape of the said foam layer, According to the objective, it can select suitably, For example, cylindrical shape is mentioned.

There is no restriction | limiting in particular as average thickness of the said foam layer, Although it can select suitably according to the objective, 1 mm-4 mm are preferable. When the average thickness is less than 1 mm, the influence of the shaft (core material) is easily picked up, and when it exceeds 4 mm, the amount of the protective agent block to be cut may be reduced.
When the foam layer is cylindrical, the thickness is defined as the distance between the cylindrical inner peripheral surface and the outer peripheral surface.
Here, the average thickness is an average value when the thickness of the foam layer is arbitrarily measured at three points.

There is no restriction | limiting in particular as a structure of the said foam layer, According to the objective, it can select suitably, For example, a closed cell type and an open cell type are mentioned. Among these, the open-cell type is preferable in that it has a small compressive residual strain and is easy to return to its original shape even when compressed, and therefore hardly deforms even in long-term use.
As shown in FIG. 4, the closed-cell foam layer is a foam layer having a structure in which holes (sometimes referred to as “cells”) are independent and impervious to air and water. Say.
As shown in FIG. 5, the open-cell foam layer refers to a foam layer having a structure in which adjacent cells are connected to each other and allow air or water to pass therethrough.

The number of cells in the foam layer is not particularly limited and may be appropriately selected according to the purpose. However, 25 cells / inch to 300 cells / inch is preferable, and 50 cells / inch to 150 cells / inch. More preferred. If the number of cells is less than 25 / inch, it may be difficult to suppress contamination of the image carrier, and if it exceeds 300 / inch, it is difficult to suppress contamination of the image carrier. There is. When the number of the cells is in the more preferable range, it is advantageous in that the suppression of the contamination of the image carrier is more excellent.
The number of the cells is an average value of values measured by the following method.
Three measurement points (reference numerals 20 and 21 in FIG. 6A) are arbitrarily selected between the vicinity of the both ends in the axial direction and the center of the protective agent supply member on the surface of the foam layer. Here, FIG. 6A is a front view of the protective agent supply member. The protective agent supply member 25 has a foam layer 24 on the outer periphery of the core member 23. In FIG. 6A, reference numeral 20 is an end measurement part, and reference numeral 21 is a central measurement part. Next, two further locations are selected in the circumferential direction at each measurement location (not shown in FIG. 6A) to determine a total of nine measurement locations. Next, the photograph screen of each measurement location is observed using a microscope. Then, as shown in FIG. 6B, a line 22 having a length corresponding to an actual size of 1 inch (about 25 mm) is drawn at the center of the photographic screen, and the number of cells in the line is counted. Find the average value. Even a small number of cells that touch the 1 inch line 22 are counted as one. For example, in the case shown in FIG. 6B, the number of cells is twelve.

There is no restriction | limiting in particular as the hardness of the said foam layer, Although it can select suitably according to the objective, 50N-500N are preferable and 100N-300N are more preferable. If the hardness is less than 50 N, it may be difficult to suppress contamination of the image carrier, and if it exceeds 500 N, it may be difficult to suppress contamination of the image carrier. If the hardness is in the more preferred range, it is advantageous in that the suppression of contamination of the image carrier is more excellent.
The hardness is an average value of values measured based on JIS K 6400 at arbitrary three points on the surface of the foam layer.

  In the foam layer, the closed-cell type, open-cell type, number of cells, hardness, etc. are adjusted as appropriate according to the type of foamed polyurethane raw material, the amount of foaming agent, reaction conditions, etc. Can be controlled.

There is no restriction | limiting in particular as a manufacturing method of the said protective agent supply member, According to the objective, it can select suitably.
As an example of the method for producing the protective agent supply member, a production example in which the foamed polyurethane is used as the material of the foam layer will be described.
First, a foamed polyurethane raw material is foam-cured by a known method to form a block-shaped foamed polyurethane. Then, after cutting into a required shape, polishing the surface, processing into a cylindrical shape having cells opened on the surface, the core material is inserted into the cylindrical shape. An adhesive may be applied to the core material in order to improve the adhesiveness with the foam layer. By these steps, the protective agent supply member is manufactured.
Another production example will be described.
A foamed polyurethane raw material is injected into a molding die for molding the protective agent supply member containing the core material, and foamed and cured. Thus, the protective agent supply member is manufactured.
Among these production methods, the method using a mold is preferable because the formation of the foam layer and the opening of the foam layer can be simultaneously performed and the processing accuracy is good.
The manufacturing method using the mold does not require complicated processing, and the foam layer having suitable opening properties can be formed. Therefore, the inner surface of the mold is separated by a fluororesin coating agent, a mold release agent, or the like. It is preferable to provide a mold layer.

<Pressure imparting member>
The pressing force applying member is not particularly limited as long as it is a member that presses the protective agent block and causes the protective agent supply member to contact the protective agent block, and can be appropriately selected according to the purpose. For example, a pressure spring is mentioned.

<Protective layer forming member>
The protective layer forming member is not particularly limited as long as it can form a protective layer by thinning the protective agent supplied to the surface of the image carrier, and can be appropriately selected according to the purpose. For example, a blade.

There is no restriction | limiting in particular as a material of the said blade, According to the objective, it can select suitably, For example, urethane rubber, hydrin rubber, silicone rubber, fluororubber etc. are mentioned.
These may be used individually by 1 type and may use 2 or more types together.
In these blades, the contact portion with the image carrier may be coated or impregnated with a low coefficient of friction material. Further, in order to adjust the hardness of the blade, a filler such as an organic filler or an inorganic filler may be dispersed.

The blade is fixed to the blade support by any method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. The thickness of the blade cannot be uniquely defined in view of the force applied by pressing, but is preferably 0.5 mm to 5 mm, and more preferably 1 mm to 3 mm.
Also, the length of the blade that protrudes from the blade support and can be deflected, that is, the so-called free length is not uniquely defined in consideration of the force applied by pressing in the same manner. Preferably, 2 mm to 10 mm is more preferable.

  As another configuration of the protective layer forming member, a coating layer of resin, rubber, elastomer or the like is coated or dipped on the surface of an elastic metal blade such as a spring plate via a coupling agent or a primer component as necessary. For example, the film may be formed by a method such as heat curing if necessary, and surface polishing if necessary.

The coating layer contains at least a binder resin and a filler, and further contains other components as necessary.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, perfluoroalkoxyalkane (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer Fluorine resins such as (FEP) and polyvinylidene chloride (PVdF); and silicone elastomers such as fluorine rubber and methylphenyl silicone elastomer.

  There is no restriction | limiting in particular as thickness of the said elastic metal braid | blade, Although it can select suitably according to the objective, 0.05 mm-3 mm are preferable and 0.1 mm-1 mm are more preferable. In the elastic metal blade, in order to suppress twisting of the blade, a process such as bending may be performed in a direction substantially parallel to the support shaft after the attachment.

  The force that presses the image carrier with the protective layer forming member is sufficient to spread the protective agent for the image carrier to form a protective layer, and the linear pressure is preferably 5 gf / cm to 80 gf / cm, preferably 10 gf. / Cm to 60 gf / cm is more preferable.

  The protective layer forming member may also serve as a cleaning member. However, in order to more reliably form the protective layer, the cleaning material is used to remove in advance the residue mainly composed of toner on the image carrier, and then the residue. It is preferable not to mix in the protective layer.

The protective layer forming apparatus will be described with reference to the drawings. FIG. 7 is a schematic sectional view of the protective layer forming apparatus of the present invention.
A protective layer forming apparatus 18 disposed facing the photosensitive drum 11 as an image carrier mainly includes a protective agent block 13, a protective agent supply member 14, a pressing force applying member 15, a protective layer forming member 16, and the like. Composed.

The protective agent block 13 contacts the roller-like protective agent supply member 14 by the pressing force of the pressing force applying member 15. The protective agent supply member 14 rotates and rubs with the photosensitive drum 11 with a linear velocity difference. At this time, the protective agent held on the surface of the protective agent supply member is supplied to the surface of the image carrier.
The protective agent supplied to the surface of the image carrier may not be a sufficient protective layer at the time of supply depending on the selection of the material type. Therefore, in order to form a more uniform protective layer, for example, a protection having a blade-like member is used. It is thinned by the layer forming member 16 to become a protective layer.

  The image bearing member on which the protective layer is formed is, for example, in a minute gap by bringing a charging roller 17 to which a DC voltage or a voltage obtained by superimposing an AC voltage is applied with a high voltage power source (not shown) into contact or in proximity. The image carrier is charged by discharging. At this time, a part of the protective layer is decomposed or oxidized due to electrical stress, and air discharge products adhere to the surface of the protective layer.

  The deteriorated protective agent for the image carrier is removed by the cleaning mechanism together with components such as toner remaining on the image carrier by a normal cleaning mechanism. Such a cleaning mechanism may also be used as the protective layer forming member 16 described above. Therefore, it is preferable to provide a cleaning mechanism including a cleaning member 12, a cleaning pressing mechanism (not shown), etc., upstream of the protective agent supply member as shown in FIG.

(Image forming method and image forming apparatus)
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, a protective layer forming step, and a fixing step, preferably including a cleaning step, and further appropriately as necessary. It includes other selected processes such as a static elimination process, a recycling process, a control process, and the like.
The image forming apparatus of the present invention comprises at least an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, a protective layer forming unit, and a fixing unit, and preferably includes a cleaning unit. In addition, it has other means appropriately selected as necessary, for example, static elimination means, recycling means, control means, and the like.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing The transfer step can be performed by the transfer unit, the protective layer forming step can be performed by the protective layer forming unit, and the fixing step can be performed by the fixing unit, The other steps can be performed by the other means.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier.
-Image carrier-
The image carrier (sometimes referred to as “photoreceptor”) is not particularly limited in terms of material, shape, structure, size, etc., and can be appropriately selected from known ones. The drum shape is preferably exemplified, and examples of the material thereof include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine.

  The image carrier (photoreceptor) used in the image forming apparatus of the present invention has a conductive support and at least a photosensitive layer on the conductive support, and further has other layers as necessary. It becomes.

  As the photosensitive layer, a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer is provided on the charge transport layer. There is a reverse layer type. In order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor, an outermost surface layer can be provided on the photosensitive layer. An undercoat layer may be provided between the photosensitive layer and the conductive support. Moreover, an appropriate amount of a plasticizer, an antioxidant, a leveling agent or the like can be added to each layer as necessary.

The conductive support is not particularly limited as long as it has a volume resistance of 1.0 × 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. Metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, and metal oxides such as tin oxide and indium oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, Alternatively, a plate made of aluminum, aluminum alloy, nickel, stainless steel or the like, and a tube subjected to surface treatment such as cutting, super-finishing, polishing, etc. after forming them into a drum shape by a method such as extrusion or drawing can be used. .
The drum-shaped support preferably has a diameter of 20 mm to 150 mm, more preferably 24 mm to 100 mm, and still more preferably 28 mm to 70 mm. When the diameter of the drum-shaped support is less than 20 mm, it may be physically difficult to arrange each step of charging, exposure, development, transfer, and cleaning around the drum. When the diameter exceeds 150 mm, The image forming apparatus may become large. In particular, when the image forming apparatus is a tandem type, since it is necessary to mount a plurality of photoconductors, the diameter is preferably 70 mm or less, and more preferably 60 mm or less. Further, an endless nickel belt or an endless stainless steel belt as disclosed in JP-A-52-36016 can also be used as the conductive support.

The undercoat layer of the photoconductor may be composed of a single layer or a plurality of layers. For example, (1) the resin is the main component, and (2) the white pigment and the resin are the main components. And (3) a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate. Among these, those containing a white pigment and a resin as main components are preferable.
Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among these, titanium oxide is particularly preferable because it is excellent in preventing injection of charges from the conductive support.
Examples of the resin include thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose; thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the thickness of the said undercoat layer, According to the objective, it can select suitably, 0.1 micrometer-10 micrometers are preferable, and 1 micrometer-5 micrometers are more preferable.

  Examples of the charge generation material in the photosensitive layer include monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments and other azo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, Cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, etc. Organic pigments or dyes; selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon, and other inorganic materials. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the charge transport material in the photosensitive layer include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, enamine compounds, butadiene compounds, distyryl. Examples thereof include compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, and triphenylmethane derivatives. These may be used individually by 1 type and may use 2 or more types together.

  As the binder resin used to form the photosensitive layer, it is electrically insulating and may be a known thermoplastic resin, thermosetting resin, photocurable resin, photoconductive resin, or the like. it can. Examples of the binder resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, ethylene-vinyl acetate copolymer, polyvinyl butyral, Polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, polysulfone, polyethersulfone, ABS resin and other thermoplastic resins, phenol resin, epoxy resin, urethane resin, melamine resin, isocyanate Examples thereof include thermosetting resins such as resins, alkyd resins, silicone resins, thermosetting acrylic resins, polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene. These may be used individually by 1 type and may use 2 or more types together.

  The outermost surface layer of the photoreceptor is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor. As the outermost surface layer, a polymer having a mechanical strength higher than that of the photosensitive layer and a material in which an inorganic filler is dispersed in the polymer are suitable. The resin used for the outermost surface layer may be either a thermoplastic resin or a thermosetting resin, but the thermosetting resin has high mechanical strength and suppresses wear due to friction with the cleaning blade. This is particularly preferable because of its extremely high capacity. If the surface layer is thin, there is no problem even if it does not have the charge transport capability, but if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, and the residual layer Since the potential rise is likely to occur, it is preferable to include the above-described charge transport material in the surface layer or to use a polymer having charge transport ability as the polymer used in the surface layer.

  Since the mechanical strength of the photosensitive layer and the outermost surface layer is generally greatly different, the outermost surface layer is worn away due to friction with the cleaning blade, and when the outermost layer disappears, the photosensitive layer is worn away immediately. It is important that the outermost surface layer has a sufficient thickness, preferably 0.1 μm to 12 μm, more preferably 1 μm to 10 μm, and particularly preferably 2 μm to 8 μm. When the thickness is less than 0.1 μm, it is too thin and is likely to be partially lost due to friction with the cleaning blade, and wear of the photosensitive layer may proceed from the lost portion. Decrease in sensitivity, increase in potential after exposure, and increase in residual potential are likely to occur. Particularly when a polymer having charge transport ability is used, the cost of the polymer having charge transport ability may be increased.

  The resin used for the outermost surface layer is preferably one that is transparent to writing light at the time of image formation and excellent in insulation, mechanical strength, and adhesion. For example, ABS resin, ACS resin, olefin-vinyl monomer Copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin , Polymethyl bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin, etc. And the like. These polymers may be thermoplastic resins, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a functional resin, the mechanical strength of the outermost surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

  The outermost surface layer preferably has a charge transporting capability. In order to provide the outermost surface layer with a charge transporting capability, the polymer used for the outermost surface layer and the above-described charge transporting material are mixed and used. A method using a polymer having a charge transporting capability for the outermost surface layer is conceivable, and the latter method is preferable because a high-sensitivity photoconductor and a small increase in residual potential can be obtained.

  The outermost surface layer preferably contains metal fine particles, metal oxide fine particles, and other fine particles in order to increase the mechanical strength of the outermost surface layer. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, titanium nitride, zinc oxide, indium oxide, and antimony oxide. Examples of the other fine particles include fluorine resins such as polytetrafluoroethylene, silicone resins, or those obtained by dispersing inorganic materials in these resins for the purpose of improving wear resistance.

  Next, the formation of the electrostatic latent image can be performed, for example, by charging the surface of the image carrier and then performing imagewise exposure, and can be performed by the electrostatic latent image forming unit. The electrostatic latent image forming unit includes, for example, at least a charger for charging the surface of the image carrier and an exposure unit for exposing the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The charger preferably has voltage applying means for applying a voltage having an AC component.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.
In the present invention, an optical back side system in which imagewise exposure is performed from the back side of the image carrier may be adopted.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

-Toner-
The toner is not particularly limited and may be appropriately selected depending on the intended purpose.For example, a polyester prepolymer having a functional group containing a nitrogen atom, a compound that extends or crosslinks with the prepolymer, a polyester, a colorant, Examples thereof include a toner prepared by crosslinking and / or extending a toner composition containing a release agent in the presence of resin fine particles in an aqueous medium. This toner can reduce the hot offset by curing the toner surface, and can prevent the toner from appearing on the image due to contamination of the fixing device.

Examples of the polyester prepolymer having a functional group containing a nitrogen atom include a polyester prepolymer having an isocyanate group, and examples of the compound that extends or crosslinks with the prepolymer include amines.
Examples of the polyester prepolymer having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate, which is a condensate of a polyol and a polycarboxylic acid. Examples of active hydrogen groups possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are particularly preferable.

  There is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably, For example, diol and a trivalent or more polyol are mentioned. Among these, a diol alone or a mixture of a diol and a small amount of a trivalent or higher polyol is preferable.

  There is no restriction | limiting in particular as said polycarboxylic acid, According to the objective, it can select suitably, For example, dicarboxylic acid and trivalent or more polycarboxylic acid are mentioned. Among these, dicarboxylic acid alone or a mixture of dicarboxylic acid and a small amount of trivalent or higher polycarboxylic acid is preferable.

  The ratio of the polyol and the polycarboxylic acid is preferably 2/1 to 1/1, and the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] to the carboxyl group [COOH] is preferably 1.5 / 1 to 1 /. 1 is more preferable, and 1.3 / 1 to 1.02 / 1 is still more preferable.

  Examples of the polyisocyanate include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); aromatic aliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; Blocked; etc. These may be used individually by 1 type and may use 2 or more types together.

  As for the ratio of the polyisocyanate, the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group is preferably 5/1 to 1/1, and 4/1 to 1 2/1 is more preferable, and 2.5 / 1 to 1.5 / 1 is still more preferable. If the [NCO] / [OH] exceeds 5, the low-temperature fixability may be deteriorated. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester becomes low, and hot offset resistance Sex worsens.

  Examples of the amines include diamines, trivalent or higher polyamines, amino alcohols, amino mercaptans, amino acids, and those obtained by blocking these amino groups. Among these amines, preferred are diamine and a mixture of a diamine and a small amount of a triamine or higher polyamine.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), or those obtained by blocking them (ketimine compounds).

  In addition, the image forming method and the image forming apparatus can be applied not only to the polymerization toner having a configuration suitable for obtaining a high-quality image as described above, but also to an irregular shaped toner by a pulverization method, Even in this case, the life of the apparatus can be greatly extended. As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the image bearing member (photosensitive member), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is caused by the electric attractive force. It moves to the surface of the image carrier (photoreceptor). As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the image carrier (photoconductor).
The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the image carrier (photosensitive member) with the transfer charger using the visible image, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The image carrier is an intermediate transfer member used for image formation by a so-called intermediate transfer method in which a toner image formed on a photosensitive member is primarily transferred to perform color superposition and further transferred to a recording medium. It may be.

-Intermediate transfer member-
As the intermediate transfer member, a material having a volume resistance value of 1.0 × 10 ^{5 to} 1.0 × 10 ¹¹ Ω · cm is preferable. When the volume resistance is less than 1.0 × 10 ⁵ Ω · cm, so-called transfer dust is generated in which the toner image is disturbed due to discharge when the toner image is transferred from the photosensitive member to the intermediate transfer member. If it exceeds 1.0 × 10 ¹¹ Ω · cm, the counter charge of the toner image remains on the intermediate transfer member after the toner image is transferred from the intermediate transfer member to a recording medium such as paper. May appear as an afterimage on other images.

As the intermediate transfer member, for example, a metal oxide such as tin oxide or indium oxide, a conductive particle such as carbon black, or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then an extrusion molded belt A cylindrical or cylindrical plastic can be used. In addition to this, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermal crosslinking reactive monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer member on an endless belt. You can also.
When the surface layer is provided on the intermediate transfer member, among the surface layer materials used for the surface layer of the photoreceptor described above, the composition excluding the charge transport material is appropriately adjusted in combination with a conductive substance, Can be used.

The transfer means (the primary transfer means and the secondary transfer means) includes at least a transfer device that peels and charges the visible image formed on the image carrier (photoconductor) to the recording medium side. It is preferable to have. There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

<Protective layer forming step and protective layer forming means>
The protective layer forming step is a step of forming a protective layer by applying a protective agent to the surface of the image carrier after transfer.
As the protective layer forming means, the protective layer forming apparatus of the present invention described above can be used.

<Fixing process and fixing means>
The fixing step is a step of fixing the visible image transferred to the recording medium using the fixing unit, and may be performed each time the toner of each color is transferred to the recording medium, or may be applied to the toner of each color. On the other hand, it may be carried out simultaneously at the same time in a state of being laminated.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

<Static elimination process and static elimination means>
The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. It is done.

<Cleaning process and cleaning means>
The cleaning step is a step of removing the electrophotographic toner remaining on the image carrier and can be suitably performed by a cleaning unit.
The cleaning unit is preferably provided downstream of the transfer unit and upstream of the protective layer forming unit.
The cleaning means is not particularly limited, and may be selected from known cleaners as long as it can remove the electrophotographic toner remaining on the image carrier. For example, a magnetic brush cleaner, Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

<Recycling process and recycling means>
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

<Control process and control means>
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, FIG. 8 is a schematic sectional view showing an example of the image forming apparatus 100 of the present invention.
Around the drum-shaped image carriers 1Y, 1M, 1C, and 1K, a protective layer forming device 2, a charging device 3, a latent image forming device 8, a developing device 5, a transfer device 6, and a cleaning device 4 are arranged, respectively. Image formation is performed by the following operation.

Next, a series of processes for image formation will be described using a negative-positive process.
An image carrier represented by a photoconductor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by a charging device 3 having a charging member.
When the image carrier is charged by the charging device, an appropriate voltage suitable for charging the image carriers 1Y, 1M, 1C, and 1K to a desired potential from a voltage application mechanism (not shown) to the charging member. A large voltage or a charging voltage obtained by superimposing an AC voltage thereon is applied.
The charged image carriers 1Y, 1M, 1C, and 1K form a latent image with a laser beam irradiated by a latent image forming device 8 such as a laser optical system (the absolute value of the exposed portion potential is the absolute value of the non-exposed portion potential). Is lower than the value).
Laser light is emitted from a semiconductor laser, and the surfaces of the image carriers 1Y, 1M, 1C, and 1K are scanned in the direction of the rotation axis of the image carrier by a polygonal polygonal mirror (polygon) that rotates at high speed.
The latent image formed in this manner is developed with a developer composed of toner particles or a mixture of toner particles and carrier particles supplied on a developing sleeve which is a developer carrying member in the developing device 5, and toner can be transferred. A visual image is formed.
At the time of developing the latent image, a voltage of an appropriate magnitude or a voltage between the exposed portion and the non-exposed portion of the image carrier 1Y, 1M, 1C, 1K is applied to the developing sleeve from a voltage application mechanism (not shown). A developing bias superimposed with an AC voltage is applied.

The toner images formed on the image carriers 1Y, 1M, 1C, and 1K corresponding to the respective colors are transferred onto the intermediate transfer body 60 by the transfer device 6 and fed from the paper feed mechanism 200, such as paper. A toner image is transferred onto the recording medium.
At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer device 6 as a transfer bias. Thereafter, the intermediate transfer member 60 is separated from the image carrier to obtain a transfer image.
Further, the toner particles remaining on the image carrier are collected by the cleaning member into the toner collecting chamber in the cleaning device 4.
As the image forming apparatus, an apparatus in which a plurality of the developing devices described above are arranged is used, and a plurality of toner images, which are sequentially produced by the plurality of developing devices, are sequentially transferred onto a transfer material, and then sent to a fixing mechanism to be heated. Even after a plurality of toner images prepared in the same manner are sequentially sequentially transferred onto an intermediate transfer member and then transferred to a recording medium such as paper, Similarly, a fixing device may be used.

  The charging device 3 is preferably a charging device arranged in contact with or close to the surface of the image carrier, and a discharge wire is used. This makes it possible to significantly suppress the amount of ozone generated during charging as compared with a corona discharger called a so-called corotron or scorotron.

(Process cartridge)
The process cartridge of the present invention comprises at least an image carrier and the protective layer forming means of the present invention, and further, charging means, exposure means, developing means, transfer means, cleaning means, charge eliminating means as necessary. It has other means such as.
The process cartridge of the present invention can be detachably provided in various electrophotographic apparatuses, and is preferably provided detachably in the image forming apparatus of the present invention described above.

Here, FIG. 9 is a schematic sectional view showing an example of the process cartridge of the present invention.
The protective cartridge forming device 2 disposed opposite to the photosensitive drum 1 as an image carrier is a protective agent block 13, a protective agent supply member 14, a pressing force applying member 15, a protective layer forming member. 16 etc.
Further, the image carrier has a surface on which the protective agent for the image carrier and the toner component partially deteriorated after the transfer process remain, but the surface residue is cleaned and cleaned by the cleaning member 12.
In FIG. 9, the cleaning member is abutted at an angle similar to a so-called counter type (leading type).
The protective member is supplied from the protective agent supply member 14 to the surface of the image carrier from which the residual toner on the surface or the deteriorated protective agent for the image carrier has been removed by the cleaning member 12. The protective layer is formed.
The image carrier having the protective layer formed in this manner is charged, and then an electrostatic latent image is formed by exposure L such as a laser, developed by the developing device 5 to be visualized, and transferred outside the process cartridge. The image is transferred to the recording medium 7 by the apparatus 6 or the like.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

(Production Example 1-1)
<Manufacture of protective agent block 1>
A mixture of 80 parts by mass of zinc stearate (GF-200, manufactured by NOF Corporation) and 20 parts by mass of boron nitride (NX5, manufactured by Momentive Performance Materials) was placed in a predetermined mold, leveled, pressure 130 kN, compression time 10 Compression molding was performed in a second to obtain a square columnar protective agent block 1 having a length of 10 mm, a width of 21 mm, and a length of 300 mm.

(Production Examples 1-2 to 1-7)
<Production of protective agent blocks 2 to 7>
In Production Example 1-1, the same procedure as in Production Example 1-1 was performed, except that the type of fatty acid metal salt, the type of inorganic lubricant, and the blending ratio of the fatty acid metal salt and the inorganic lubricant were changed to those shown in Table 1. Thus, protective agent blocks 2 to 7 were obtained.

(Production Example 1-8)
<Manufacture of protective agent block 8>
Zinc stearate (GF-200, manufactured by NOF Corporation) was melted and then put into a predetermined mold to obtain a protective agent block 8.
The shape of the obtained protective agent block 8 was a rectangular column shape having a length of 10 mm, a width of 21 mm, and a length of 300 mm.

(Production Example 1-9)
<Manufacture of protective agent block 9>
After melting a mixture of 80 parts by mass of zinc stearate (GF-200, manufactured by NOF Corporation) and 20 parts by mass of boron nitride (NX5, manufactured by Momentive Performance Materials), the mixture was put in a predetermined mold and the protective agent block 9 Got.
The shape of the obtained protective agent block 9 was a rectangular column shape having a length of 10 mm, a width of 21 mm, and a length of 300 mm.

In the table, zinc stearate is GF-200 manufactured by NOF Corporation, boron nitride is NX5 manufactured by Momentive Performance Materials, calcium stearate is manufactured by Wako Pure Chemical Industries, and mica is SA manufactured by Miyoshi Chemical. Mica.

(Production Example 2-1)
<Manufacture of protective agent supply member 1>
Polyether polyol, polyisocyanate, water, and a catalyst were reacted to obtain a foamed polyurethane. The obtained polyurethane foam was cut into a square pillar shape, and a hole for inserting a core material (diameter 6 mm, length 365 mm, made of stainless steel) was opened. The core material was inserted into the hole to fix the foamed polyurethane and the core material. Furthermore, the protective agent supply member 1 in which the foam layer made of foamed polyurethane was formed by polishing the outer peripheral surface of the foamed polyurethane was produced.
The obtained protective agent supply member 1 was in the form of a roller. The foam layer was an open cell type, and the average thickness was 3 mm. The number of cells was 25 / inch, and the hardness was 147N.

<Measurement>
The number of cells and the hardness were measured by the following methods.
<< Number of cells >>
On the surface of the foam layer, three measurement points were arbitrarily selected between the vicinity of the both ends in the axial direction of the protective agent supply member and the central portion. Next, two more locations were selected in the circumferential direction at each measurement location to determine a total of 9 measurement locations. Next, the photograph screen of each measurement location was observed using a microscope. Then, a line having a length corresponding to an actual size of 1 inch (about 25 mm) was drawn at the center of the photographic screen, the number of cells in the line was counted, and the average value of the nine locations was obtained. Even a small number of cells that touched the 1 inch line were counted as one.

<< Hardness >>
Hardness was measured based on JIS K 6400 at any three points on the surface of the foam layer, and the values were averaged.

(Production Examples 2-2 to 2-9)
<Manufacture of protective agent supply members 2-9>
In Production Example 2-1, protective agent supply members 2 to 9 were produced in the same manner as in Production Example 2-1, except that the blending amounts of water and catalyst at the time of foaming polyurethane production and the stirring conditions were appropriately changed.
The obtained protective agent supply members 2 to 9 were in the form of rollers. The foam layer was an open cell type, and the average thickness was 3 mm. Table 2 shows the number of cells and the hardness of the protective agent supply members 2 to 9.

Example 1
In place of the zinc stearate block used in the same apparatus, the protective agent block 1 was disposed in an image forming unit of imgio MP C5000 manufactured by Ricoh Co., Ltd. Moreover, it replaced with the brush roller currently used with the apparatus, and the said protective agent supply member 1 was arrange | positioned.
The structure of the protective layer forming apparatus in the apparatus modified as described above is shown in FIG.
In addition, the Rigoh Co., Ltd. imgio MP C5000 used in this example employs the technology disclosed in Japanese Patent Application Laid-Open No. 2007-293740 as a pressing force applying member that presses the protective agent block and contacts the protective agent supply member. The protective agent block can be pressed at a constant pressure and a uniform pressure in the longitudinal direction over time. The pressure is 12N in terms of spring pressure.

<Evaluation>
An A4 size original with an image area ratio of 5% was continuously fed through 20,000 sheets. In addition, by using a worn cleaning blade, the charging member was easily contaminated.
<< Image carrier contamination >>
Contamination of the image carrier after passing 20,000 sheets was visually observed and evaluated according to the following criteria. The results are shown in Table 3.
◎: Not contaminated at all ○: Contaminated but at an acceptable level △: Although the level is worse than ○, a defective image may not appear depending on the output image ×: Largely contaminated

<< Charging member contamination >>
Contamination of the charging member (charging roller) after passing 20,000 sheets was visually observed and evaluated according to the following criteria. The results are shown in Table 3.
◎: Not contaminated at all ○: Contaminated but at an acceptable level △: Although the level is worse than ○, a defective image may not appear depending on the output image ×: Largely contaminated

<< Consumer block consumption >>
The consumption of the protective agent block per unit travel distance of the image carrier was measured.
The consumption of the protective agent block per unit mileage during printing 1,000 sheets from the first sheet to the 1,000th sheet was evaluated according to the following criteria. The results are shown in Table 3.
A: 0.15 (g / km) ≦ (consumption) <0.5 (g / km)
○: 0.5 (g / km) ≦ (consumption) <0.7 (g / km)
Δ: 0.7 (g / km) ≦ (consumption) <1.0 (g / km)
X: 1.0 (g / km) ≦ (consumption) or (consumption) <0.15 (g / km)
FIG. 10 shows the consumption of the protective agent block per unit travel distance up to 20,000 sheets.

(Examples 2-15, Comparative Examples 1-4)
In Example 1, an image forming apparatus was produced and evaluated in the same manner as in Example 1 except that the type of the protective agent block and the type of the protective agent supply member were changed to those shown in Table 3. . The evaluation results are shown in Table 3 and FIGS.
The brush roller as the protective agent supply member in Comparative Examples 2 to 4 is a standard material as a brush roller of an image forming apparatus, which is made of PET, fiber thickness is 5.7 d, and fiber density is 100 kF. is there.

  Examples 1 to 15 were excellent results in any of the contamination of the image carrier, the contamination of the charging member, and the consumption amount of the protective agent block.

Compared with the case where the protective agent block is only the fatty acid metal salt (Example 12), the mixture of the fatty acid metal salt and the inorganic lubricant (for example, Examples 2, 13, 14, and 15) is a point of contamination of the charging member. It was better. In particular, when the blending ratio of the fatty acid metal salt and the inorganic lubricant is 60/40 to 90/10 (for example, Examples 14 and 15), both the contamination of the image carrier and the contamination of the charging member were very excellent.
What used boron nitride for the protective agent block (for example, Example 2) was more excellent in terms of contamination of the charging member than that using mica (for example, Example 7).

When the number of cells in the foam layer of the protective agent supply member is 50 / inch to 150 / inch (for example, Examples 2, 8, and 9), the number of cells is 50 / inch to 150 / inch. Compared with those outside the above range (for example, Examples 1, 4, and 5), the image carrier was more excellent in terms of contamination.
When the hardness of the foam layer of the protective agent supplying member is 100N to 300N (for example, Examples 2, 10, and 11), the hardness is not in the range of 100N to 300N (for example, Examples 3, 4, and Compared with 5), the image carrier was more excellent in terms of contamination.

Comparative Example 1 using a protective agent block produced by melt molding was inferior to the Examples in terms of contamination of the image carrier and consumption of the protective agent block.
The comparative example using the brush roller as the protective agent supply member tended to be inferior to the embodiment in at least one of contamination of the charging member and consumption of the protective agent block.

  In Examples 1-15, as shown in FIGS. 10-12, in practical press, consumption of a protective agent block is not too much, it is not too small, is an appropriate amount, and is a necessary amount stably over a long period of time. Was consumed. That is, a necessary amount of protective agent has been supplied to the image carrier stably over a long period of time.

In Comparative Example 1, as shown in FIG. 13, the consumption of the protective agent block was less than the required amount.
In Comparative Examples 2 and 4, as shown in FIG. 13, when the number of sheets passed was small, the consumption of the protective agent block was too large, which was uneconomical. In addition, consumption decreased with time, and the behavior of consumption was unstable.

  Since the protective layer forming apparatus of the present invention can suppress contamination of the image carrier and can stably supply a necessary amount of protective agent to the image carrier over a long period of time even in practical pressing, It is suitably used for a photographic image forming method, an image forming apparatus, a process cartridge, and the like.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Protective layer forming apparatus 3 Charging apparatus 4 Cleaning apparatus 5 Developing apparatus 6 Transfer apparatus 7 Recording medium 8 Latent image forming apparatus 11 Photosensitive drum 12 Cleaning member 13 Protective agent block 14 Protective agent supply member 15 Pressure applying member 15 DESCRIPTION OF SYMBOLS 16 Protective layer formation member 17 Charging roller 18 Protective layer formation apparatus 20 End measurement part 21 Center measurement part 22 Wire 23 Core material 24 Foam layer 25 Protective agent supply member 50 Manufacturing apparatus 51 Lower mold 52 Horizontal 53 End mold 54 Upper mold 60 Intermediate transfer body 100 Image forming apparatus 200 Paper feed mechanism G Powder

JP 2006-350240 A JP 2009-150986 A

Claims (10)

A protective agent block formed by compression molding and containing a fatty acid metal salt;
A roller-shaped protective agent having a core material that scrapes off the protective agent from the protective agent block and supplies the protective agent to the surface of the image carrier , and an open-cell foam layer formed on the outer periphery of the core material A protective layer forming apparatus comprising a supply member. The protective layer forming apparatus according to claim 1, wherein the foam layer has an average thickness of 1 mm to 4 mm.   The protective layer forming apparatus according to claim 1, wherein the protective agent block further contains an inorganic lubricant.   The protective layer forming apparatus according to any one of claims 1 to 3, wherein the foam layer has a cell of 25 pieces / inch to 300 pieces / inch and has a hardness of 50N to 500N.   The protective layer forming apparatus according to any one of claims 1 to 4, wherein the fatty acid metal salt is zinc stearate.   The protective layer forming apparatus according to claim 3, wherein the inorganic lubricant is boron nitride. A pressing force applying member that presses the protective agent block and contacts the protective agent supply member;
The protective layer forming apparatus according to claim 1, further comprising a protective layer forming member that forms a protective layer by thinning the protective agent supplied to the surface of the image carrier. An electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A developing step of developing the electrostatic latent image with toner to form a visible image;
A transfer step of transferring the visible image to a recording medium;
A protective layer forming step of forming a protective layer by applying a protective agent to the surface of the image carrier after transfer;
At least a fixing step of fixing the transferred image transferred to the recording medium,
An image forming method, wherein the protective layer forming step is performed by the protective layer forming apparatus according to claim 1. An image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on the image carrier;
Developing means for developing the electrostatic latent image with toner to form a visible image;
Transfer means for transferring the visible image to a recording medium;
A protective layer forming means for forming a protective layer by applying a protective agent to the surface of the image carrier after transfer;
And at least fixing means for fixing the transferred image transferred to the recording medium,
8. The image forming apparatus according to claim 1, wherein the protective layer forming means is the protective layer forming apparatus according to claim 1.   A process cartridge comprising at least an image carrier and the protective layer forming apparatus according to claim 1, wherein the process cartridge is detachable from a main body of the image forming apparatus.