JP2008170655A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease degradation of a recycled toner; to prevent wax filming on a photoreceptor; to obtain high wear resistance of a cleaning blade; and to maintain preferable image characteristics for a long period of time. <P>SOLUTION: The image forming method includes a developing step of developing an electrostatic latent image formed on a photoreceptor with a toner containing wax, a transfer step of transferring the toner image developed in the developing step onto a transfer material, then cleaning step of cleaning off the toner remaining on the photoreceptor by a cleaning blade made of a rubber elastic material, and a toner recycling step of conveying the recovered toner by cleaning to the developing unit. The cleaning blade comprises a rubber layer containing inorganic fine particles in a portion to be in contact with the photoreceptor, and the rubber layer containing inorganic fine particles shows the Young's modulus of 70 to 95 kgf/cm<SP>2</SP>and a rubber hardness of 67 to 75 degrees. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method and an image forming apparatus, and more particularly, in an image forming method provided with a toner recycling system to which toner containing wax is applied, the deterioration of the recycled toner is small, and the wax on the photosensitive member The present invention relates to an image forming method and an image forming apparatus in which filming does not occur, the wear resistance of a cleaning blade is high, and good image characteristics can be maintained over a long period of time.

2. Description of the Related Art Conventionally, in a transfer type image forming apparatus, a latent image is formed by exposing a document image on, for example, a photoreceptor as a latent image carrier uniformly charged by a charger, and then a developing device is applied to the latent image. The toner is attached to make a visible image as a toner image. This toner image is transferred to transfer paper or an intermediate transfer medium by a transfer device. The toner remaining on the photoconductor after transfer is removed from the photoconductor by a cleaning device, and the photoconductor is continuously used repeatedly.
Conventionally, the toner collected from the cleaning device has been collected and discarded in the container. However, in recent years, from the viewpoint of resource saving, the toner recycling system that transports the toner collected from the cleaning device to the developing unit and reuses it. Has been widely adopted.
However, there is a problem that the physical properties of the recycled toner collected by cleaning and transported to the developing unit are different from the physical properties of the toner contained in the start developer or the virgin toner replenished in the developing device.
Normally, the surface of the toner is surface-treated with a treatment agent such as silica or alumina so that the physical properties such as fluidity are stably maintained. However, the recycled toner is removed from the surface treatment agent or the toner. The particles are buried in the particles, the charge amount varies, and the fluidity is remarkably lowered, causing various abnormal images.

As a means for preventing such deterioration of the recycled toner, the proportion of particles having a volume reference diameter of 5.04 μm or less is 60% by volume or more on the surface of colored fine particles containing at least a binder resin, a colorant, and a charge control agent. There has been proposed a toner for a recycling system in which hydrophobic silica having a particle ratio of 20.2 μm or less having a particle ratio of 90% by volume or more is adhered (see, for example, Patent Document 1: Japanese Patent Laid-Open No. 2000-122339).
Moreover, in patent document 2 (Unexamined-Japanese-Patent No. 2000-10335), the anatase type titanium oxide whose half-width of a maximum diffraction peak is 0.1 to 0.4 degree | times and whose average primary particle diameter is 11-25 nm is inorganic. There has been proposed a toner for developing an electrostatic latent image, which is used as fine particles and the surface of the anatase-type titanium oxide is coated with 10 to 30 wt% of a silane coupling agent.
In the prior art described above, the deterioration of the toner is suppressed by the physical properties of the external additive.
Recently, however, there has been an increasing demand for a longer service life, particularly from the viewpoint of reducing maintenance, etc., and it is possible to sufficiently suppress the deterioration of recycled toner over a long period of time simply by improving only the external additive. However, there is a problem that a good image cannot be obtained for a long time.

Also, by adding the charge amount of the base toner and the external additive close to the charge amount of the toner, a toner with little fluctuation in the charge amount is produced even when the recycled toner is buried or detached. The proposal about this is also made (for example, refer patent document 3: Unexamined-Japanese-Patent No. 2002-268283).
According to this, although fluctuations in the charge amount of the recycled toner can be suppressed, toner aggregation cannot be sufficiently suppressed, and it is difficult to obtain a good image for a long time in the recycled toner system electrophotographic apparatus.

In recent years, there has been a demand for toner that can be fixed with low energy in order to save energy and increase speed.
In view of this point, a soft resin having a low molecular weight that can be fixed at a low temperature is used. However, since such a resin has a problem of hot offset, a method of incorporating a wax into the toner is also performed.
However, in a process using a toner containing a wax, there is a problem of so-called wax filming on the photoreceptor, in which the wax component in the toner adheres to the photoreceptor.
When wax filming on the photoreceptor occurs, various abnormal images are generated. For example, so-called image blur, in which the outline of an image is blurred and the resolution is significantly reduced under high-temperature and high-humidity conditions or an oxidizing gas atmosphere such as NOx or ozone, is promoted by wax filming. In particular, in a system using recycled toner, the toner base tends to come into contact with the surface of the photoreceptor due to the external additive being buried in the recycled toner, and wax filming is likely to occur.

  As a means for suppressing wax filming, the angle between the axial cutting surface and the surface of the photosensitive member at the contact portion with the photosensitive member is 90 degrees as the angle with respect to the upstream direction of rotation of the photosensitive member. There is known an image forming apparatus that regulates the range of 120 degrees. However, since the blade tip has a special shape, the strength of the blade cannot be sufficiently obtained, and the durability of the cleaning blade cannot be said to be high, and a good image cannot be obtained over a long period of time (Patent Document 4: JP, 2006-64716, A).

  Conventionally, in the toner recycling system using the wax-containing toner as described above, the deterioration of the recycled toner is small, the wax filming to the photosensitive member is hardly generated, the durability of the cleaning blade is high, and the long-term There has not yet been proposed an image forming method and an image forming apparatus that can obtain a good image.

JP 2000-122339 A JP 2000-10335 A JP 2002-268283 A JP 2006-64716 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method equipped with a toner recycling system to which a toner containing wax is applied, in which the deterioration of the recycled toner is small, wax filming on the photoreceptor does not occur, and the cleaning blade is resistant to abrasion. The object is to maintain high image characteristics over a long period of time with high wear.

The above problems are solved by the present invention described below.
(1) “Developing step of developing the electrostatic latent image formed on the photosensitive member with toner containing wax, transferring step of transferring the toner image developed by the developing step onto a transfer material, In the image forming method including at least a cleaning step of cleaning the toner remaining on the photosensitive member with a cleaning blade which is a rubber elastic member, and a toner recycling step of conveying the toner collected by the cleaning to a developing unit, the cleaning The part where the blade is in contact with at least the photoreceptor is constituted by a rubber layer containing inorganic fine particles, and the rubber layer containing the inorganic fine particles has a Young's modulus of 70 to 95 kgf / cm ² and a rubber hardness of 67 to 75 degrees. An image forming method characterized in that "
(2) “Image forming method according to item (1), wherein the inorganic particles have a volume average particle diameter of 0.01 to 5 μm”,
(3) The image forming method described in (2) above, wherein the content of the inorganic fine particles is 1 to 20 wt.% With respect to the constituent components of the rubber layer containing the inorganic fine particles. "
(4) "The image forming method according to any one of (1) to (3) above, wherein the inorganic fine particles are silica",
(5) "The image forming method according to any one of (1) to (4) above, wherein the inorganic fine particles are titanium oxide",
(6) “An image forming apparatus having at least a charging unit, an image exposing unit, a developing unit, a transferring unit, a fixing unit, a cleaning unit, and a toner recycling unit for the photosensitive member, An image forming apparatus characterized in that an image is formed by the image forming method according to any one of 5).

  As in the present invention, in an image forming apparatus having a toner recycling mechanism and using a toner containing wax, a urethane rubber blade in which an appropriate particle size and an appropriate amount of inorganic fine particles are dispersed in urethane rubber is cleaned. By using it as a blade and defining the rubber hardness and Young's modulus of the urethane rubber, there is little deterioration of the recycled toner, no wax filming on the photoconductor occurs, and the cleaning blade has wear resistance. An image forming apparatus that is high and maintains good image characteristics over a long period of time can be obtained.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following examples.
As a cause of deterioration of the recycled toner and occurrence of wax filming, the toner staying at the edge portion of the cleaning blade is pressed onto the photosensitive member, so that the external additive of the toner is buried, and the toner wax One possible cause is that the components migrate to the photoreceptor.
The blade edge portion of the cleaning blade when the photosensitive member is driven is deformed in a state where the blade edge is drawn in the advancing direction of the photosensitive member due to the frictional force between the blade and the photosensitive member. If this pulling-in deformation is large, it is considered that the amount of staying toner increases and a greater stress is applied to the toner.

Therefore, it was examined how to suppress the blade edge pull-in and deformation.
We focused on materials with high Young's modulus as a means of suppressing deformation due to the blade edge being pulled. In the case of a normal urethane rubber blade, the Young's modulus can be increased by selecting the raw material, but generally, the rubber hardness increases as the Young's modulus increases. If the rubber hardness is high, the adhesion between the blade and the photosensitive member is lowered, and defective cleaning is likely to occur in part or the blade is easily chipped.
The inventors diligently studied a method for increasing the Young's modulus without increasing the hardness. As a result, it is possible to increase the Young's modulus without increasing the rubber hardness by dispersing the appropriate particle size and the appropriate amount of inorganic fine particles in the urethane rubber. Physical properties of the specified rubber hardness and Young's modulus Therefore, the deformation due to the blade edge being pulled in when the photosensitive member is driven is suppressed, and it is possible to suppress the deterioration of the recycled toner and the wax filming on the photosensitive member. Further, by adding inorganic fine particles to urethane rubber, the inorganic fine particles acted as a reinforcing material for the rubber blade, and the wear resistance of the blade was improved.
As described above, there is little deterioration of the recycled toner, wax filming on the photoconductor does not occur, the cleaning blade has high wear resistance, and it is possible to maintain good image characteristics over a long period of time. . Details will be described below.

<Cleaning blade>
In the cleaning blade used in the present invention, at least the blade edge in contact with the photoreceptor is constituted by a rubber layer in which inorganic fine particles are dispersed.
The form of the blade may be a rubber layer (102) containing inorganic fine particles (101) as shown in FIG. 1, or a normal rubber layer (103) containing no inorganic fine particles as shown in FIG. A blade having a two-layer structure in which a rubber layer (102) containing inorganic fine particles (101) is bonded to each other may be used, and only the tip of the blade edge portion of a normal rubber layer (103) not containing inorganic fine particles as shown in FIG. May be a rubber layer (102) containing inorganic fine particles (101). There is no limitation as long as it contains inorganic fine particles at least at the blade edge portion.

Rubber physical properties of the rubber obtained by dispersing inorganic fine particles, the Young's modulus is at 70 kgf / cm ² or more 95kgf / cm ² or less, and a rubber hardness of 75 degrees or lower than 67 degrees. By increasing the Young's modulus, deformation due to the blade edge portion being pulled in is suppressed. Further, by adding inorganic fine particles, it is possible to control so as not to increase the hardness even if the Young's modulus is increased, and the adhesion to the photoreceptor can be maintained.
When the Young's modulus is less than 70 kgf / cm ^2, the deformation of the blade edge portion becomes large, the effect of suppressing wax filming on the photoreceptor cannot be sufficiently obtained, and the recycled toner is also easily deteriorated. On the other hand, if the Young's modulus is greater than 95 kgf / cm ² , sufficient adhesion to the photoreceptor cannot be obtained, and sufficient cleaning properties cannot be obtained. When the rubber hardness is less than 67 degrees, the blade edge portion is largely pulled in, so that the effect of suppressing wax filming on the photoconductor is not sufficiently obtained, and the recycled toner is easily deteriorated. On the other hand, when the angle is greater than 75 degrees, the adhesion between the blade and the photoreceptor cannot be obtained, and cleaning failure or blade chipping is likely to occur.
From the above, rubber properties of the rubber layer formed by dispersing inorganic fine particles Young's modulus is at 70 kgf / cm ² or more 95kgf / cm ² or less, and a rubber hardness of 75 degrees or lower than 67 degrees.
The hardness was measured using a value measured with a JIS-K6301 A-type hardness meter, and the Young's modulus was measured according to JIS-K6394.

In the present invention, the Young's modulus 70 kgf / cm ² or more 95kgf / cm ² or less, and, following 75 degrees 67 degrees rubber hardness, for example, the type of prepolymer used during blade manufacturing (or aromatic or aliphatic , The number of functional groups, the length and number of alkylene groups in the molecule), the type and amount of curing agent, the type of added fine particles, the added amount, etc. It can be adjusted relatively easily and reliably by the amount added. For example, as will be understood from each example (Table 1) specifically shown later, the Young's modulus can be adjusted relatively easily mainly by adjusting the amount of inorganic fine particles added.

  A conventionally well-known material can be used as a kind of inorganic fine particle disperse | distributed to urethane rubber. Examples thereof include fine powders made of inorganic materials such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, and potassium titanate. Particularly preferred are silica, titanium oxide and alumina, and when these are used, the abrasion resistance is particularly good. In addition, a mixture of these plural types of inorganic fine particles can be favorably used.

The inorganic fine particles preferably have a volume average particle size of 0.01 to 5 μm. Particles smaller than 0.01 μm may not function sufficiently as a reinforcing material, and good blade wear resistance may not be obtained. If it exceeds 5 μm, even if inorganic fine particles are dispersed in the rubber blade, the inorganic fine particles are detached from the rubber, and sufficient durability cannot be obtained.
The volume average particle size of the inorganic fine particles can be measured with a nano-track particle size distribution measuring device (UPA-EX150 manufactured by Nikkiso Co., Ltd.) which is a powder particle size distribution measuring device by a dynamic light scattering method. . The shape of the inorganic fine particles that can be measured by dispersing the inorganic fine particles in a suitable solvent such as N-methyl-2-pyrrolidone (NMP) is not particularly limited, and for example, spherical, needle-like, and fibrous shapes can be used.

The amount of the inorganic fine particles added is 1 to 20 wt. % Is desirable. 20 wt. If it is more than%, the inorganic fine particles may inhibit rubber cross-linking and durability may not be sufficient, or Young's modulus may increase but hardness may also increase. Young's modulus and hardness May be difficult to control within the specified range.
Addition amount is 1 wt. When the ratio is smaller than%, the reinforcing effect of the blade may not be sufficiently obtained, or the Young's modulus may be little increased.
As described above, the inorganic fine particles are added in an amount of 1 to 20 wt. % Addition amount is desirable.

  A conventionally known material can be used as the rubber elastic body of the cleaning blade, but polyurethane rubber is preferred. Polyurethane rubber is usually prepared by using a polyol component and a polyisocyanate component to prepare a prepolymer, followed by adding a curing agent and a catalyst as necessary, and crosslinking in a predetermined mold, followed by post-crosslinking in a furnace. After being allowed to stand, it is produced by standing and aging at room temperature.

  In the present invention, as the high molecular weight polyol, for example, a polyester polyol which is a condensate of alkylene glycol and an aliphatic dibasic acid, for example, ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate Polycaprolactone-based polyols such as ester polyols, polyester polyols such as polyester polyols of alkylene glycol and adipic acid such as ethylene butylene adipate ester polyol, ethylene neopentylene adipate ester polyol, poly (oxytetramethylene) glycol, poly ( A polyether polyol such as oxypropylene) glycol is used.

  Other low molecular weight polyols include, for example, 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis (2-hydroxyethyl) ether, 3,3′-dichloro-4,4′-diaminodiphenyl. Dihydric alcohols such as methane, 4,4'-diaminodiphenylmethane, 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylol Mention may be made of trihydric and higher polyhydric alcohols such as ethane, 1,1,1-tris (hydroxyethoxymethyl) propane, diglycerin, pentaerythritol.

As the polyisocyanate component for the urethane rubber in the present invention, 1.5-naphthalene diisocyanate (NDI), diphenylmethane-4.4′-diisocyanate (4.4′-MDI), diphenylmethane-2.4′-diisocyanate ( 2.4′-MDI), hydrogenated MDI (H ₁₂ MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), 2,4-toluene diisocyanate (2,4-TDI or TDI-100), 2, 6-toluene diisocyanate (2,6-TDI), TDI-80 (20% remaining is 2,6-TDI), TDI-65 (45% remaining is 2,6-TDI), tolidine diisocyanate (TODI), Tris (4-phenylisocyanate thiophosphate, triphenyl Tantriisocyanate, N, N ′ (4.4′-dimethyl-3.3′-diphenyldiisocyanate) uredion (dimer of TDI), 4,4 ′, 4 ″ -trimethyl-3,3 ′, 3 ″ -Known polyisocyanates such as triisocyanate-2,4,6-triphenyl cyanurate (TDI trimer), TDI trimer polymer, etc. can be used. A prepolymer is prepared using polycaprolactone ester and 4,4′-diphenylmethane diisocyanate as the polyisocyanate component and based on this, with or without the addition of other polyols and / or polyisocyanates as desired. After adding a curing agent and a catalyst as necessary, cross-linking in a predetermined mold, and post-cross-linking in a furnace Is preferably one produced by leaving aged at room temperature.

  Specific examples of the curing catalyst include 2-methylimidazole and 1,2-dimethylimidazole, and 1,2-dimethylimidazole is particularly preferably used. Such a catalyst is usually used in an amount of 0.01 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, based on 100 parts by weight of the main agent.

The blade can be produced by a conventionally known method, and at least inorganic fine particles may be dispersed in the prepolymer before molding. For example, the cleaning blade used in the present invention can be obtained as follows.
Urethane elastomer is mainly obtained by adding a small amount of antifoaming agent to the prepolymer and curing agent as the main components, mixing it uniformly, putting it in a mold and heating and curing, but the inorganic fine particles were heated and melted. It is possible to obtain a cleaning blade containing desired inorganic fine particles by dispersing in a prepolymer or by dispersing in a curing agent which is relatively low in molecular weight and liquid at room temperature.
The inorganic fine particles may be subjected to a surface treatment with a silane coupling agent or the like in advance, if necessary, in order to improve the dispersibility and improve the adhesion to the rubber-like elastic material for the cleaning blade.

<Toner>
Next, the toner used in this embodiment will be described. The toner used in this embodiment is not particularly limited as long as it contains at least a binder resin, a wax, and a colorant. It is also possible to use toners produced by various toner production methods such as known pulverization methods and polymerization methods.
As the wax used as the release agent for the toner according to the exemplary embodiment, a known material may be used. For example, polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbon (paraffin wax, sasol) Wax etc.); Carbonyl group containing wax etc. are mentioned.
Among these, particularly preferred as the carbonyl group wax are polyester acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin. Tribehenate, 1,18-octadecanediol distearate, etc.); polyalkanol esters (trimellitic acid tristearyl, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenyl amide, etc.); polyalkylamides ( Trimellitic acid tristearyl amide, etc.); and dialkyl ketones (distearyl ketone, etc.).

  Binder resins include polystyrene, polyvinyl toluene and other styrene and substituted homopolymers, styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-acrylic acid. Methyl copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer Polymer, styrene-o-chloromethyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isobutylene Copolymer, styrene-maleic acid copolymer Styrene copolymers such as styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic Acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be used alone or in combination.

  The polyester resin is obtained by a polycondensation reaction between an alcohol and an acid. Examples of the alcohol include polyethylene glycol, diethyl glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4- Diols such as propylene glycol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A Etherified bisphenols such as these, divalent alcohol monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, other divalent alcohol monomers, sorbitol, 1, 2, 3, -Hexanetetrol, 1,4-sarbitane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol And trihydric or higher alcohol monomers such as 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and 1,3,5-trihydroxymethylbenzene.

  Examples of the carboxylic acid used to obtain the polyester resin include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. Acids, adipic acid, sebacic acid, malonic acid, divalent organic acid monomers in which these are substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, anhydrides of these acids, lower alkyl esters and Dimer from linolenic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxylic acid-2-methyl A trivalent or higher polyvalent carboxylic acid monomer such as 2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid embol trimer, and anhydrides of these acids; Can be mentioned.

  Further, examples of the epoxy resin include a polycondensate of bisphenol A and epichlorohydrin. For example, Epomic R362, R364, R365, R366, R367, R369 (above, manufactured by Mitsui Petrochemical Co., Ltd.), Epototo YD-011, YD There are commercially available products such as -014, YD-904, YD-017 (above, manufactured by Tohto Kasei Co., Ltd.), Epocoat 1002, 1004, 1007 (above, manufactured by Shell Chemical Co., Ltd.).

  Colorants include carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, Hansa Yellow G, rhodamine 6G lake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl. Conventional dyes and pigments such as methane dyes, monoazo dyes, disazo dyes, and dyes can be used alone or in combination.

  Further, the toner does not have any inconvenience even if it contains a drug to be contained for the purpose of controlling the triboelectric chargeability as in the case of the toner that is usually used. As such so-called polarity control agents, for example, metal complexes of monoazo dyes, nitrohumic acids and salts thereof, metal complexes of salicylic acid, naphthoic acid, dicarboxylic acids such as Co, Cr, Fe, Zn, etc. are used alone or in combination. However, it is not limited to these. The polarity control agent used in the color toner needs to be colorless, and a polymer type polarity control material having polarity is preferably used.

  Note that a fluidity modifier can be added to the toner used in the exemplary embodiment. Examples of fluidity modifiers include, for example, organic resin fine particles, metal soaps, polytetrafluoroethylene fluororesins, lubricants such as zinc stearate, or abrasives such as acid value cerium and silicon carbide, and generally fluidity Known metal oxides used for the purpose of modification, typically metal oxide fine particles such as silicon oxide, titanium oxide and aluminum oxide, and particles whose surface is hydrophobized. Hydrophobizing the surface of any of these fine powders has an excellent effect in terms of fluidity. In order to hydrophobize the surface, for example, a silicon compound generally known as a silane coupling agent or a silylating agent is brought into contact with and reacted with the particle surface.

  Examples of the hydrophobizing agent include trichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, ethyldichlorosilane, diethylchlorosilane, triethylchlorosilane, propyldichlorosilane, dipropyldichlorosilane, and tripropylchlorosilane, which are typical chlorosilanes. And alkylchlorosilane, phenylchlorosilane and the like. Examples of the fluorine-substituted product include fluoroalkylchlorosilanes and perfluoroalkylchlorosilanes.

  Examples of silylamines include typical hexamethyldisilazane, diethylaminotrimethylsilane, and diethylaminotrimethylsilane. Examples of silylamides include typical N, O-bistrimethylsilylacetamide, N-trimethylsilylacetamide, bistrimethylsilyltrifluoroacetamide, and the like.

  Examples of alkoxysilanes include methyltrialkoxysilane, dimethyldialkoxysilane, trimethylalkoxysilane, ethyldialkoxysilane, diethylalkoxysilane, triethylalkoxysilane, propyltrialkoxysilane, dipropyldialkoxysilane, and tripropylalkoxysilane. Alkylchlorosilane, phenylalkoxysilane having a phenyl group, and the like. In addition, fluoroalkyl alkoxysilanes, perfluoroalkylalkoxysilanes as fluorine-substituted products, dimethylsilicone oil and derivatives thereof as silicone oils, fluorine-substituted products, siloxanes such as disiloxane, hexamethyldisiloxane, etc. It becomes possible to use a compound used as a generally known hydrophobizing agent.

In addition, a well-known toner manufacturing method used in the present embodiment can be used, and for example, a pulverization method, a polymerization method, or the like can be used. For example, in the case of the pulverization method, a binder resin, a wax, a colorant, and in other cases, a charge control agent, etc. are mixed using a mixer or the like, and then kneaded using a kneader such as a hot roll or an extruder. Then, it is solidified by cooling, pulverized by pulverization such as a jet mill, and then classified. It should be noted that a mixer such as a super mixer or a Henschel mixer is used to add inorganic powder as a fluidity modifier to the toner.
In the case of the polymerization method, for example, an organic solvent liquid of a toner material containing at least a resin material for a binder and / or its prepolymer, a colorant, and a wax in an organic solvent is formed into fine droplets in an aqueous medium. After dispersion, the prepolymer in the droplets is subjected to crosslinking and / or extension reaction while being obtained by removing the organic solvent and the aqueous medium, or / and during or after the dispersion. Thereafter, the organic solvent and the aqueous medium can be removed for production.

  Preferably, at least in an organic solvent, a compound having active hydrogen and a polymer having a site capable of reacting with the compound, or a self-polymerizable material having active hydrogen and a site capable of reacting with it in the molecule at the same time The organic solvent and the colorant and the release agent are dissolved or dispersed, preferably in the form of a composition containing them, and after reacting with or reacting with the site capable of reacting with the active hydrogen. The aqueous medium can be removed, washed and dried. It is also possible to adjust the circularity of the toner by adjusting the stirring strength during the reaction or by stirring strongly after drying. Various materials can be used as the resin material or / and its prepolymer, and in particular, a polyester resin or / and a polyester prepolymer can be used. These are merely examples, and they can be manufactured by a method other than such a manufacturing method.

<Image forming apparatus>
Next, an image forming method and an image forming apparatus using the image forming method will be described. FIG. 4 shows a schematic configuration diagram of an example of an image forming apparatus applied to the image forming method of the present invention.
The photoreceptor (1) has a drum shape, but may be a sheet shape or an endless belt shape.
A charging member (2) is disposed around the photoconductor (1). If necessary, a pre-transfer charger, a transfer charger, a separation charger, and a pre-cleaning charger are arranged. It is assumed that known means such as the first are also arranged.
The charging member (2) in FIG. 4 represents a charging roller, but the charging roller may be in contact with the photoreceptor (1), but an appropriate gap (about 10 to 200 μm) is provided between them. By using a close arrangement, the wear amount of both can be reduced. It is effective that the voltage applied to the charging member (2) is obtained by superimposing an AC component on a DC component in order to stabilize charging and suppress charging unevenness.
As the transfer means, the above charger can be generally used. In FIG. 4, a transfer roller (5) is provided.
Further, light sources such as an image exposure unit (3) and a charge removal lamp (9) include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). Conventionally known luminescent materials such as) can be applied. In order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter are used.
These light sources can also be applied to processes such as a transfer process, a static elimination process, a cleaning process, or a pre-exposure that use light irradiation together.
The toner developed on the photoconductor (1) by the developing unit (4) is transferred to the transfer paper conveyed from the paper feed tray (10), but not all is transferred, and the photoconductor (1 There is also toner remaining on the surface, and such toner is removed from the photoreceptor (1) by the cleaning blade (61) of the cleaning unit (6).
Although cleaning may be performed only with a cleaning blade, a cleaning brush such as a fur brush may be used in combination.
The toner image transferred onto the transfer paper by the transfer device is conveyed to the fixing device (8), where the toner image is fixed on the paper and discharged.
When the electrophotographic photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. If this is developed with negative (positive) polarity toner (electrodetection fine particles), a positive image can be obtained, and if developed with positive (negative) polarity toner, a negative image can be obtained.

A conventionally known recycling apparatus can be used as a toner recycling apparatus that conveys the collected toner from the cleaning section to the developing section. For example, a toner recycling apparatus that rotates the screw member and conveys toner can be used. An example of an image forming apparatus equipped with a toner recycling device using a screw member is shown in FIG. The surface of the photoreceptor (1) is developed with toner by the developing device (4) and transferred to a transfer material by the transfer device (5).
Untransferred toner remaining on the photoreceptor (1) is scraped off by the cleaning blade (61) of the cleaning device (6). A toner discharge port (62) is provided for discharging the scraped toner collected out of the cleaning device. The toner discharge port (62) is connected to a recycled toner transport pipe (11) that transports the collected toner to the developing unit. A screw member (12) is provided inside the recycled toner transport pipe (11), and the recovered toner is transported to the developing unit and reused as recycled toner by rotating the screw.
Further, at the connection portion between the recycled toner transport pipe (11) and the developing unit (4), a toner discharge port (13) is provided on the recycled toner transport pipe (11) side, and a toner receiving port (14) is provided on the developing unit. Thus, the toner collected by the cleaning unit is returned to the developing unit, and the toner is recycled.

EXAMPLES Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following examples.
<About production of cleaning blade>
Table 1 shows a list of configurations and physical properties of the blades produced. This cleaning blade was produced by the following procedure.
The blades A to G and the blades J to K are blades containing inorganic fine particles in the entire urethane rubber as shown in FIG. 1 and can be manufactured by the following procedure.
A predetermined amount of inorganic fine particles is added to a predetermined amount of prepolymer heated and melted at 90 ° C., and treated with AR-500 (manufactured by Thinky) at 1000 rpm for 3 minutes to prepare a heated melt composed of the prepolymer and the inorganic fine particles. Then, vacuum defoaming was performed while heating with a vacuum dryer. A predetermined amount of a curing agent was added to the prepolymer heated melt in which the obtained inorganic fine particles were dispersed, and the mixture was quickly stirred with an agitator until uniform, then degassed under reduced pressure, a release agent was applied, and the mixture was preheated to 150 ° C. It was poured into a mold and allowed to stand for 60 minutes in a thermostatic bath heated to 150 ° C. to cure, thereby producing a urethane rubber having a thickness of 2 mm.
Next, this is taken out from the mold, left in a constant temperature bath at 120 ° C. for 24 hours, and further left in a constant temperature and humidity chamber at 23 ° C. and 55 ± 10% RH for one week, so that the entire rubber layer as shown in FIG. A rubber plate member for a cleaning blade in which inorganic fine particles were dispersed was obtained.
Next, the obtained rubber plate was cut out to a predetermined size and adhered to a predetermined metal holder to prepare a cleaning blade.

Further, the blade H and the blade I not containing inorganic fine powder were produced by the following method.
A predetermined amount of the prepolymer heated and melted at 90 ° C. was vacuum defoamed while being heated in a vacuum dryer. A predetermined amount of curing agent is added to the obtained prepolymer heated melt, and the mixture is quickly stirred with an agitator until it is uniform, then degassed under reduced pressure, a release agent is applied, and the mixture is poured into a mold preheated to 150 ° C. A urethane rubber having a thickness of 2 mm was produced by allowing it to stand for 60 minutes in a thermostatic bath heated to a predetermined temperature and curing.
Next, this was taken out from the mold, left in a constant temperature bath at 120 ° C. for 24 hours, and further left in a constant temperature and humidity chamber at 23 ° C. and 55 ± 10% RH for one week to obtain a rubber plate member for a cleaning blade.
Next, the obtained rubber plate was cut out to a predetermined size and adhered to a predetermined metal holder to prepare a cleaning blade.

(Example 1)
Evaluation conditions <Evaluation cleaning blade>
The blade A in Table 1 produced by the above method was used.
<Use developer>
The toner used for the evaluation was a toner containing carnauba wax, a volume average particle diameter of 6.5 μm, and a circularity of 0.94.
The toner was mixed with a carrier (average particle size 55 μm) of silicone-coated Cu—Zn ferrite core material at a ratio of 4 parts by weight to 96 parts by weight to prepare a developer.
<Paper passing test equipment>
A monochrome copying machine “imageNeo 900PRO” (manufactured by Ricoh) equipped with a mechanism for rotating the screw member as shown in FIG. 5 and conveying the toner from the cleaning unit to the developing unit was used.
The experiment was conducted by replacing the cleaning blade with the blade A and replacing the developer to be used with the developer.

Evaluation items 750,000 sheets were tested using a chart with a printing rate of 6% under the conditions described above, and the following items were evaluated after the sheet passing test.
<About filming evaluation>
The photoreceptor was taken out, and the filming state was observed on the surface of the photoreceptor with a laser microscope (VK-9500 manufactured by Keyence).
A five-level rank evaluation was performed, and a state in which there was no filming and remained unchanged from the initial stage was set to 5, and an inferiority was determined to be 1. Rank 3 or higher is necessary to withstand actual use.
<Evaluation of Buried Degree of Toner External Additive>
The recycled toner conveyed at the outlet of the toner recycling apparatus connected to the developing unit was collected. The collected toner was observed using an FE-SEM and visually ranked in five levels (5 is the best).
<Blade edge observation>
The blade edge after the paper passing test was observed with a laser microscope (VK-9500, manufactured by Keyence Corporation), and the wear width was measured. At the same time, the blades were observed for chipping.
<Image evaluation>
◎ Background dirt The S-3 chart was copied, and the toner adhesion on the background was observed visually and with a magnifying glass to evaluate the rank.
It was determined that 5 was the best, 1 was poor, and the practically problematic rank was 2 or less.
Fine line resolution The copier was left in an environment of 30 ° C. and 85% RH for 12 hours, and then the fine line portion of the S-3 chart was observed visually and using a magnifying glass to determine whether it could be discriminated.
2.0, 2.2, 2.5, 2.8, 3.2, 3.6, 4.0, 4.5, 5.0, 5.6, 6.3, 7.1 When there is a thin line of / mm and image blurring occurs due to wax filming, the resolution of the thin line that can be read deteriorates, and thus the thin line that was read was observed.

(Example 2)
In Example 1, the evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade B.

(Example 3)
In Example 1, evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade C.

Example 4
In Example 1, evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade D.

(Example 5)
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the cleaning blade to be mounted was Blade E.

(Example 6)
In Example 1, evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade F.

(Example 7)
In Example 1, the evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was the blade G.

(Comparative Example 1)
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the cleaning blade to be mounted was a blade H to which inorganic fine particles were not added.
During the paper passing test, at the end of 400,000 sheets, the background stain was severe and a cleaning failure occurred, and a good image could not be obtained. Therefore, the paper passing test was stopped, and the test was ended with 400,000 sheets. Example 1 The same evaluation items were implemented.

(Comparative Example 2)
In Example 1, evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade I to which inorganic fine particles were not added.
During the paper passing test, at the end of 400,000 sheets, three streaky cleaning defects occurred, and when 500,000 sheets, the cleaning defect was severe and a good image could not be obtained. The test was terminated and the same evaluation items as in Example 1 were performed.

(Comparative Example 3)
In Example 1, the evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade J.
During the paper passing test, two streak-like cleaning defects occurred at the end of 650,000 sheets. The paper passing test was performed as it was, and 750,000 sheets were tested in the same manner.

(Comparative Example 4)
In Example 1, evaluation was performed in exactly the same manner as in Example 1 except that the cleaning blade to be mounted was Blade K.
Table 2 lists the evaluation results.

It is a figure which shows an example of the cleaning blade used for this invention. It is a figure which shows another example of the cleaning blade used for this invention. It is a figure which shows another example of the cleaning blade used for this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus applied to an image forming method of the present invention. FIG. 2 is a diagram illustrating an example of an image forming apparatus equipped with a toner recycling apparatus using a screw member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging member 3 Image exposure part 4 Developing unit 5 Transfer roller 6 Cleaning unit 8 Fixing device 9 Static elimination lamp 10 Paper feed tray 11 Recycled toner conveyance pipe 12 Screw member 13 Toner discharge port 14 Toner receiving port 61 Cleaning blade 62 Toner Discharge port 100 Cleaning blade 101 Inorganic fine particle 102 Inorganic fine particle-containing rubber layer 103 Normal rubber layer 110 Support tool 111 Blade

Claims (6)

A developing step of developing the electrostatic latent image formed on the photosensitive member with a toner containing wax, a transferring step of transferring the toner image developed in the developing step onto a transfer material, and then on the photosensitive member In the image forming method including at least a cleaning step of cleaning the toner remaining on the toner with a cleaning blade that is a rubber elastic body, and a toner recycling step of transporting the toner collected by the cleaning to the developing unit, the cleaning blade includes at least The portion in contact with the photoreceptor is constituted by a rubber layer containing inorganic fine particles, and the rubber layer containing the inorganic fine particles has a Young's modulus of 70 to 95 kgf / cm ² and a rubber hardness of 67 to 75 degrees. An image forming method. The image forming method according to claim 1, wherein the inorganic particles have a volume average particle diameter of 0.01 to 5 μm. The content of the inorganic fine particles is 1 to 20 wt.% With respect to the constituent components of the rubber layer containing the inorganic fine particles. The image forming method according to claim 2, wherein the image forming method is%. The image forming method according to claim 1, wherein the inorganic fine particles are silica. The image forming method according to claim 1, wherein the inorganic fine particles are titanium oxide. 6. An image forming apparatus comprising at least a charging unit, an image exposing unit, a developing unit, a transferring unit, a fixing unit, a cleaning unit, and a toner recycling unit for a photoreceptor, and the image according to any one of claims 1 to 5. An image forming apparatus, wherein an image is formed by a forming method.

Images