JPH08297449A - Image forming method - Google Patents

Abstract

PURPOSE: To obtain such an image forming method that when a spherical toner of a small particle size is used for development, the spherical toner having a small particle size remaining on the surface of a photoreceptor or other material can be surely removed by bringing the edge of a cleaning blade into contact with the photoreceptor surface after transfer and that a high definition good image can be stably obtd. CONSTITUTION: The edge of a cleaning blade 28 is brought into contact with the surface of a photoreceptor 21 after transfer to remove a spherical toner 4 having 3-9μm volume average particle size or other material remaining on the photoreceptor surface. In this method, a fluidizing agent 4a having 30-300m<2> /g BET specific surface area is externally added to the toner. This fluidizing agent 4a is made to remain in 5-50μm length range in a wedge-like resident part S formed between the cleaning blade 28 and the surface of the photoreceptor 21 on the upstream side, in the moving direection of the photoreceptor 21, of the contact part of the edge of the cleaning blade 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method in an image forming apparatus using an electrophotographic system such as a copying machine, a printer and a facsimile, and more particularly to a transfer material for transferring a toner image formed on the surface of a photoconductor. The present invention relates to an image forming method capable of stably cleaning a residual substance such as toner remaining on the surface of the photoconductor after being transferred to the surface by a cleaning blade composed of an elastic member.

[0002]

2. Description of the Related Art In forming an image in an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, etc., generally, as shown in FIG. 1, a cylindrical photosensitive member 1 is rotated. After the surface of the photoconductor 1 is charged by the charging device 2, an electrostatic latent image is formed on the photoconductor 1 by an appropriate exposure means (not shown), and the electrostatic latent image on the photoconductor 1 is formed. Toner 4 in the developer is supplied to the image from the developing device 3 to form a toner image on the surface of the photoconductor 1, and the toner image is transferred onto a transfer material 6 such as paper by a transfer / separation charger 5. The transfer material 6 is separated from the photoconductor 1.

Then, the transfer material 6 is guided to a fixing roller 7, and the toner image transferred as described above is fixed on the transfer material 6 by the fixing roller 7, while being transferred onto the surface of the photosensitive member 1 after the transfer. The residual material such as the toner 4 is removed from the surface of the photoconductor 1 by the cleaning device 8, and then the potential remaining on the photoconductor 1 is removed by a charge removing device (not shown).

Here, as the cleaning device 8 for removing the residue such as the toner 4 remaining on the surface of the photoconductor 1 after the transfer as described above, various devices such as those using a cleaning brush are used. However, as shown in FIG. 1, the end of the cleaning blade 8a made of an elastic member is brought into contact with the surface of the photosensitive member 1 and the cleaning blade 8a is generally inexpensive and simple in construction.
In many cases, the residual substance such as the toner 4 remaining on the surface of the photoconductor 1 is removed.

On the other hand, in recent years, in order to reproduce a high-definition image in the image forming apparatus as described above,
Toner 4 having a small average particle diameter has come to be used for developing.

Here, the toner 4 having a small particle diameter as described above is mixed with a binder resin and an additive such as a colorant, and the mixture is melt-kneaded and cooled as is conventionally done. After that, when it is produced by a so-called kneading and pulverizing method in which this kneaded product is pulverized and classified,
The yield was poor, the manufacturing cost was high, and there were problems in terms of technical aspects and productivity.

Therefore, in order to manufacture the toner 4 having a small particle diameter as described above, a wet granulation method such as a suspension polymerization method or an emulsion dispersion method has come to be used.

Here, when the toner 4 as described above is manufactured by the suspension polymerization method, a solution containing a polymerizable monomer, a colorant and, if necessary, other additives is added.
The resin obtained by the above monomer is suspended in a solvent in which it is not dissolved, the above monomer is polymerized to granulate the toner particles, and then the solvent is removed to obtain the toner 4, and the toner 4 is emulsified and dispersed. In the production by the method, a resin, a colorant and, if necessary, other additives are dissolved or dispersed in a non-aqueous solvent, the solution is suspended in an aqueous dispersion solvent, and then the above-mentioned non-aqueous solution is heated. The solvent was removed to granulate the toner particles, and then the above aqueous dispersion solvent was removed to obtain Toner 4.

When the toner 4 is manufactured by the wet granulation method as described above, the toner 4 having a small particle diameter having a relatively narrow particle diameter distribution is obtained. The toner 4 thus obtained is generally used. Its shape was a sphere close to a true sphere.

Therefore, as described above, the end portion of the cleaning blade 8a is brought into contact with the surface of the photoconductor 1 to remove the residue such as the toner 4 remaining on the surface of the photoconductor 1 after the transfer. In this case, since the toner 4 has a spherical shape with a small particle size as described above, the toner 4 often slips through the cleaning blade 8a to cause cleaning failure, which causes a problem such as noise in an image to be formed. occured.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a copying machine,
It is an object of the present invention to solve the above various problems in an image forming apparatus using an electrophotographic system such as a printer and a facsimile.

That is, according to the present invention, the end portion of the cleaning blade made of an elastic member is brought into contact with the surface of the photoconductor after transfer to remove the above-mentioned residual substances such as toner remaining on the surface of the photoconductor. In removing with this cleaning blade, even when using a toner having a small particle size and spherical shape produced by the wet granulation method as described above, this toner or the like is removed from the surface of the photoreceptor by the cleaning blade. An object of the present invention is to reliably remove and prevent defective cleaning as in the conventional case, and to stably perform good and high-definition image formation without noise or the like.

[0013]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention develops an electrostatic latent image formed on a moving photoconductor with a developer containing toner to obtain a photoconductor. After a toner image is formed on the surface and the toner image is transferred to a transfer material, the end of a cleaning blade made of an elastic member is brought into contact with the surface of the photoconductor to leave the toner remaining on the surface of the photoconductor. In the image forming method in which the residual substances such as the above are removed, the developer has a spherical toner having at least a volume average particle diameter of 3 to 9 μm and a BET specific surface area externally added to the toner. Thirty
Using what and ~300m ² / g of fluidizing agent is contained, which is formed between the cleaning blade and the photosensitive member surface in the photosensitive member movement direction upstream side than the portion where the end portion of the cleaning blade is in contact A residue such as toner is retained in the wedge-shaped retention portion, and the fluidizing agent is retained in the retention portion in the range of 5 to 50 μm from the portion where the end of the cleaning blade and the photosensitive member are in contact with each other. The residual substance such as toner remaining on the surface of the photoconductor is removed.

Here, in the image forming method of the present invention, a toner having a volume average particle diameter of 3 to 9 μm is used as a developer for developing the electrostatic latent image formed on the photosensitive member. The reason is that a high-definition image can be obtained by this image forming method, and it is preferable to use a toner of 3 to 6 μm.

As the spherical toner having a particle size of 3 to 9 μm, a toner manufactured by a well-known wet granulation method generally used in the past is used. Those produced by a granulation method including a polymerization process such as a synthetic method or an emulsion polymerization method, or a granulation method such as an emulsion dispersion method are used.

Here, in obtaining the toner as described above by the suspension polymerization method, polymerization is carried out by adding a polymerizable monomer as a component of the binder resin, a polymerization initiator, a colorant and, if necessary, other additives. The composition is suspended in a medium of a non-solvent system, and in this state, the composition is polymerized for granulation.

Further, when the toner as described above is produced by the emulsion polymerization method, only fine particles can be obtained by the general emulsion polymerization method. Therefore, the method known as the seed polymerization method is preferably used. A part of the polymerizable monomer and a polymerization initiator are added to an aqueous medium or an aqueous medium to which an emulsifier is added, and the mixture is stirred to emulsify, and then the rest of the polymerizable monomer is gradually dropped to form fine particles. Then, the particles are used as seeds for polymerization in droplets of a polymerizable monomer containing a colorant and other additives so as to be granulated.

The granulation method including the polymerization process is not limited to the above, and examples thereof include soap-free emulsion polymerization method, microcapsule method (interfacial polymerization method, in-situ polymerization method, etc.), non-aqueous dispersion polymerization method, etc. The toner as described above can also be manufactured by the above method.

When obtaining the toner as described above by the emulsion dispersion method, a binder resin component is mixed with a colorant and, if necessary, other additives, these are dissolved in a solvent, and this solution is used as a non-solvent. Granulate by suspending in the system medium.

As the binder resin in the above-mentioned toner, known resins which have been generally used in toners can be used, for example, styrene-based resin, (meth) acrylic-based resin, olefin-based resin, polyester. Use of thermoplastic resins such as epoxy resins, amide resins, carbonate resins, polyethers, polysulfones, etc., thermosetting resins such as epoxy resins, urea resins, urethane resins, copolymers and polymer blends thereof. You can

As the colorant to be contained in the toner, various known pigments and dyes that have been generally used can be used.

For example, black pigments include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, ferrite and magnetite; yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide,
Mineral Fast Yellow, Nickel Titanium Yellow,
Navels Yellow, Naphthol Yellow S, Bunzer Yellow G, Bunzer Yellow 10G, Benzidine Yellow G, Benzidine GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, etc .;
Red pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange R
K, benzidine orange G, induslen brilliant orange GK, red iron oxide, cadmium red, red lead, permanent red 4R, resole red, pyrazolone red, watching red, lake red C, lake red D, brilliant carmine 6B, eosin lake,
Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, Balkan Fast Orange GG, Permanent Red F4RH, Permanent Carmine FB, etc .; as blue pigment, navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, etc. can be used. . When these colorants are contained in the toner, the colorant is added to 100 parts by weight of the binder resin described above in order to prevent the toner from being sufficiently colored and the chargeability of the toner from becoming unstable. 1 to 20 parts by weight, preferably 3 to 15 parts by weight.

In the toner used in the present invention, a charge control agent and an anti-offset agent are added to the binder resin in order to properly charge the toner and to improve the fixing property of the toner. Desired additives such as can be added.

Here, when the charge control agent is added to the toner, a nigrosine dye, a quaternary ammonium salt, a polyamine compound, an imidazole compound or the like may be used as the positive charge control agent for positively charging the toner. As a negative charge control agent capable of negatively charging the toner, a calixarene compound, a chromium complex salt type azo dye, a copper phthalocyanine dye, a chromium complex salt, a zinc complex salt,
Aluminum complex salt etc. can be used. When the charge control agent is contained in the toner, it is generally 0.1 to 10 parts by weight, preferably 0.5 to 100 parts by weight of the binder resin so that the toner is appropriately charged. ~ 5 parts by weight should be added.

When an anti-offset agent is added to improve the fixability of the toner, examples of the anti-offset agent include low molecular weight polyethylene wax, low molecular weight oxidized polyethylene wax, low molecular weight polypropylene wax, and low molecular weight oxidized type wax. Polypropylene wax, higher fatty acid wax, higher fatty acid ester wax, Sazol wax, carnauba wax, etc. may be used alone or in combination of two or more. When the above-described offset preventive agent is contained in the toner, it is generally necessary to obtain a sufficient offset preventive effect and to prevent the fluidity of the toner from being lowered by the addition of the offset preventive agent. , 1 to 100 parts by weight of the binder resin of the toner
It is added in an amount of 15 parts by weight, preferably 2 to 8 parts by weight.

Further, in order to impart magnetism to this toner and use it as a magnetic toner, metals exhibiting magnetism such as iron, nickel and cobalt in the above binder resin, these metals and zinc, antimony, aluminum, An alloy or mixture of lead, tin, beryllium, bismuth, manganese, selenium, titanium, tungsten, vanadium, etc., or a magnetic substance such as magnetite, γ-hematite, various ferrites may be added.

On the other hand, as a fluidizing agent which is externally added to and mixed with the toner, silica fine particles, titanium oxide fine particles, alumina fine particles, magnesium fluoride fine particles, silicon carbide fine particles, boron carbide fine particles, titanium carbide fine particles, zirconium carbide fine particles, Inorganic particles such as boron nitride particles, titanium nitride particles, zirconium nitride particles, magnetite particles, molybdenum disulfide particles, aluminum stearate particles, magnesium stearate particles, zinc stearate particles can be used. Is a silane coupling agent from the viewpoint of improving stability against environmental changes such as humidity changes.
It is preferable to use a hydrophobized one with a titanium coupling agent, higher fatty acid, silicone oil or the like.

In the present invention, the fluidizing agent has a BET specific surface area of 30 to 300 m ² / g.
This is because it improves the fluidity and chargeability of the toner, and the fluidizing agent is used as a wedge formed between the cleaning blade and the surface of the photoreceptor as described above. The appropriate amount of fluidizing agent acts as a cleaning blade while allowing a suitable amount of toner to remain on the surface of the photoconductor and the offset preventing agent to be sufficiently removed from the surface of the photoconductor by accumulating an appropriate amount in a stagnant portion. As it slips through the photoconductor, the lubricity between the cleaning blade and the photoconductor is improved to prevent abrasion of the cleaning blade and the photoconductor, and the cleaning blade vibrates due to friction with the photoconductor. This is to prevent noise from being generated and the cleaning blade from being greatly deformed and flipped up.

Further, as the above-mentioned fluidizing agents, two types of fluidizing agents may be used in combination by separating their functions into those that are easily retained in the retaining portion and those that enhance the lubricity. Then, as the fluidizing agent that is easily retained in the retaining portion, one having a BET specific surface area of 30 to 80 m ² / g, preferably 30 to 60 m ² / g is used, while a fluidizing agent that enhances lubricity is used. Has a BET specific surface area of 80 to 300 m ² /
g, preferably 100 to 300 m ² / g.

In addition, when such a fluidizing agent is externally added and mixed with the toner, the toner is provided with sufficient fluidity, and at the same time, the cleaning function and the lubricating function as described above are imparted to the toner. 0.05 to 1.5% by weight, preferably 0.1 to 1.0, of such a fluidizing agent.
Try to add it by weight%.

Further, in the toner used in the present invention, in addition to the above fluidizing agent, in order to improve cleaning performance and the like, styrene type, acrylic type, methacrylic type, benzoguanamine, silicone, Teflon, polyethylene Alternatively, various resin fine particles such as polypropylene may be added.

The developer used in the present invention may be a one-component system obtained by externally mixing a fluidizing agent and the like with the toner as described above, but a two-component developer containing a carrier added thereto. It may be a system.

Here, as the carrier used in the two-component type developer, known carriers generally used in the past can be used. For example, carriers composed of magnetic particles such as iron and ferrite. It is possible to use a resin-coated carrier obtained by coating such magnetic particles with a resin, a binder type carrier obtained by dispersing the above-mentioned fine powder of the magnetic material in a binder resin, or the like. From the standpoint of durability against spent, etc., resin-coated carrier using silicone resin, copolymer resin (graft resin) of organopolysiloxane and vinyl monomer, fluororesin, etc. as the coating resin, or binder. It is preferable to use a binder type carrier using a polyester resin or a polyolefin resin as the resin.

From the viewpoint of using such a carrier to obtain a high-definition image and preventing carrier fogging, the average particle size is 20 to 80 μm.
m, preferably 30 to 60 μm.

Further, in the present invention, as the cleaning blade for removing the residue such as the toner remaining on the surface of the photosensitive member, a cleaning blade composed of a known elastic material which has been generally used conventionally can be used. , For example,
A material made of polyurethane rubber, silicone rubber or the like can be used.

When the end of such a cleaning blade is brought into contact with the surface of the photosensitive member to remove the residue such as toner remaining on the surface of the photosensitive member, the cleaning blade and the surface of the photosensitive member are separated from each other. The above-mentioned wedge-shaped retention portion formed between the above-mentioned fluidizing agents is 5 to 50 μm from the portion where the end of the cleaning blade abuts on the photoreceptor.
When the length of the staying portion is less than 5 μm, the residue such as the toner remaining on the surface of the photoconductor cannot be sufficiently removed, while when the length is 50 μm or more. , The amount of fluidizing agent that slips between the cleaning blade and the photoreceptor is reduced,
This is because the lubricity between the cleaning blade and the photoconductor deteriorates, the cleaning blade and the photoconductor are immediately worn, and the cleaning blade vibrates due to friction with the photoconductor to make a sound or flip up.
Preferably, the length of the fluidizing agent retention portion is 15 to 30 μm.
Adjust so that it is within the range of m.

In order to more effectively remove the residual substances such as toner remaining on the surface of the photoreceptor, the fluidizing agent is retained in the retaining portion as described above, and the fluidizing agent is further retained. The toner and the like are retained in a portion upstream of the portion in the moving direction of the photoconductor, and the length of the portion where the fluidizing agent, the toner, and the like are retained and is still is 10 to 10.
The thickness is 100 μm, preferably 30 to 80 μm.

Here, the length of the staying portion of the fluidizing agent, the toner and the like staying in the staying portion is determined by the material of the cleaning blade, the angle at which the cleaning blade is brought into contact with the photosensitive member, the surface of the photosensitive member. Characteristics, moving speed of the photoconductor,
It varies depending on the characteristics of the toner and the fluidizing agent used, and by appropriately adjusting these, the length of the retention portion of the fluidizing agent, the toner, etc. is controlled within the above range.

When the portion where the fluidizing agent, the toner and the like stay in the staying portion is lengthened, generally, a cleaning blade having a low hardness and a large thickness is used, and as shown in FIG. When the end portion of 8a is pressed against the surface of the photoconductor 1, the photoconductor 1
The cleaning blade 8a with respect to the pressure contact angle .theta.
Use a material having a high surface roughness and a high coefficient of friction, and use a fluidizing agent having a small BET specific surface area and low fluidity as described above and adding the fluidizing agent to the toner. In addition, for the toner, use a toner with a large particle size and a large shape that greatly deforms from a spherical shape, and a low charge amount and low fluidity. To shorten the length, reverse the above case.

[0040]

In the image forming method according to the present invention, after the toner image formed on the surface of the photoconductor is transferred to the transfer material, the residue such as toner remaining on the surface of the photoconductor is removed from the surface of the photoconductor. When removing with the cleaning blade with the end contacted with the edge of the cleaning blade, wedge-shaped retention that retains residue such as toner on the upstream side in the moving direction of the photoreceptor with respect to the part where the edge of the cleaning blade contacts the surface of the photoreceptor In this case, the fluidizing agent externally added to the toner and having a BET specific surface area of 30 to 300 m ² / g is retained within a range of 5 to 50 μm from the portion in contact with the end of the cleaning blade. Even when a toner having a small volume average particle diameter of 3 to 9 μm and a spherical shape is used, the toner is well removed from the surface of the photoconductor.

Further, since the amount of the fluidizing agent retained in the retaining portion is set within the above range, an appropriate amount of the fluidizing agent slips between the cleaning blade and the photoconductor, whereby the cleaning blade and the surface of the photoconductor are removed. Has improved lubricity,
Abrasion of the cleaning blade and the photoconductor will be reduced, and the cleaning blade will not vibrate due to friction with the photoconductor to make a sound, or will not be greatly deformed and turned up, and stable cleaning can be performed. .

[0042]

EXAMPLES In the following, according to the image forming method of the present invention, it is possible to reliably remove the residue such as toner remaining on the surface of the photoconductor after transfer by the cleaning blade, and to perform good image formation as described below. A specific description will be given based on experimental examples.

In this experimental example, a two-component developer using toner and carrier was used as the developer.

As the toner in this developer, the toner manufactured as follows is used.

Here, in manufacturing the toner,
60 parts by weight of styrene and 3 parts of n-butyl methacrylate
5 parts by weight, 5 parts by weight of methacrylic acid, 0.5 parts by weight of 2,2-azobis- (2,4-dimethylvaleronitrile), 3 parts by weight of low molecular weight polypropylene (manufactured by Sanyo Chemical Industry Co., Ltd .: Viscole 605P). , Carbon black (MA # 8 manufactured by Mitsubishi Kasei Co., Ltd.) and zinc salicylate complex (E-84 manufactured by Orient Chemical Industry Co., Ltd.) in an amount of 3 parts by weight, and these are mixed by a sand stirrer for polymerization. The composition was adjusted.

Then, this polymer composition was stirred in an aqueous solution of gum arabic having a concentration of 3% (manufactured by Tokushu Kika Kogyo: TK-
Using an auto homomixer) at a rotational speed of 4500 rpm, a polymerization reaction was performed at a temperature of 60 ° C. for 6 hours to obtain spherical toner particles having an average particle diameter of 5 μm. Then, the toner particles were repeatedly filtered and washed with water, and then the filtered material was sufficiently air-dried at a temperature of 35 ° C. and a humidity of 30% RH to obtain a spherical toner having an average particle diameter of 5 μm. .

With respect to 100 parts by weight of this toner, a BET specific surface area of 140 cm ² / g was used as a fluidizing agent.
Hydrophobic silica (manufactured by Hoechst: H-2000) of 0.
3 parts by weight were added, and these were mixed and stirred by a Henschel mixer, and the hydrophobic silica was externally added and mixed with the above toner.

On the other hand, as a carrier in the developer,
The carrier manufactured as described below was used.

Here, in manufacturing the carrier, 100 parts by weight of polyester resin (NE-1110 manufactured by Kao Corporation) and inorganic magnetic powder (MFP-2 manufactured by TDK Corporation) are used.
Was used in an amount of 600 parts by weight and carbon black (manufactured by Mitsubishi Kasei Kogyo Co., Ltd .: MA # 8) in an amount of 2 parts by weight. These were thoroughly mixed by a Henschel mixer and pulverized. ， Cylinder head part 17
The mixture is melt-kneaded using an extrusion kneader set to 0 ° C., the kneaded product is cooled, coarsely pulverized, and further finely pulverized by a jet mill, and the finely pulverized product obtained is classified by an air classifier. Thus, a binder type carrier having an average particle diameter of 55 μm was obtained.

Then, the carrier is mixed with the above toner to prepare a developer having a toner mixing ratio of 5% by weight, and this developer is supplied to the developing device 23 in the experimental device 20 shown in FIG. I tried to do the experiment.

Here, in this experimental apparatus 20, a photoconductor 21 for inspection having a transparent charge transport layer provided on the surface of a transparent glass tube formed in a cylindrical shape is used, and the photoconductor 21 for this inspection is used. Is rotated and the surface of the photoconductor 21 is charged by the charging device 22, and then the toner is supplied from the developing device 23 to the surface of the photoconductor 21. The photoconductor to which the toner is supplied in this way The end of the cleaning blade 28 is brought into contact with the surface of the photoconductor 21 so that the toner on the surface of the photoconductor 21 is removed by the cleaning blade 28. Then, the potential remaining on the photoconductor 1 is removed by the static eliminator 29. I tried to eliminate the static electricity.

The cleaning blade 28 has a rubber hardness of 67 degrees, a Young's modulus of 55 kg / cm ² ,
Polyurethane rubber with 52% impact resilience (Hokushin Rubber Co., Ltd.)
This cleaning blade 2
8 is pressed against the surface of the photoreceptor 21, the contact angle .theta. Is appropriately adjusted while being measured by the angle measuring device 28a.
The pressure contact force for pressing the end portion of 8 to the surface of the photoconductor 21 is appropriately adjusted by the pressure contact spring 28b.

Then, the state in which the toner and the like on the surface of the photoconductor 21 are removed by the cleaning blade 28 as described above is photographed by the CCD camera 30 provided on the inner peripheral side of the photoconductor 21 to remove the toner and the like. It was examined how the residue was removed from the surface of the photoconductor 21.

Here, when the state where the toner and the like on the surface of the photosensitive member 21 are removed by the cleaning blade 28 is examined by the CCD camera 30, the end portion of the cleaning blade 28 moves as shown in FIG. It deforms when it comes into contact with the surface of the photoconductor 21,
A wedge-shaped retention portion S is formed on the upstream side in the moving direction of the photoconductor 21 from the portion where the end of the cleaning blade 28 contacts the surface of the photoconductor 21.

Then, the toner 4 and the fluidizing agent 4a externally mixed with the toner 4 are gradually accumulated in the staying portion S, and the end portion of the cleaning blade 28 is first moved to the photosensitive member 21.
While the fluidizing agent 4a having a small particle size is sequentially accumulated in the portion in contact with the surface of the fluidizing agent, the fluidizing agent 4 thus accumulated.
A part of a passes through the nip portion n between the cleaning blade 28 and the photoconductor 21, and the fluidizing agent 4a is retained in the retaining portion S for a predetermined length (L ₁ ). At the same time, in the portion on the upstream side in the moving direction of the photoconductor 21 from the portion where the fluidizing agent 4a stays in this manner, the toner 4 having a larger particle size than the fluidizing agent 4a is accumulated and accumulated in order from the smaller particle diameter. In this way, the fluidizing agent 4a and the toner 4 and the like are retained in the retaining portion S in a state of retaining for a predetermined length (L ₂ ), and the fluidizing agent 4a and the toner 4 and the like hardly move in this portion. It was in a stationary state.

Further, in the portion on the upstream side in the moving direction of the photoconductor 21 from the portion where the fluidizing agent 4a, the toner 4 and the like are retained, the toner carried along with the rotation of the photoconductor 21 is transferred. 4 and the like are gradually decelerated to form a deceleration portion D, and the toner 4 and the like having a large particle diameter that are carried along with the rotation of the photoconductor 21 are removed from the photoconductor 21 at the deceleration portion D. , Toner with small particle size 4
And the like gradually move forward in the deceleration portion D, and when the material moves forward in this manner, the toner 4 having a large particle diameter in the deceleration portion D is pushed out and removed from the photoconductor 21. .

When the toner 4 or the like reaches the portion where the toner 4 or the like having a small particle diameter is retained through the deceleration portion D as described above, the particle diameter is larger than that of the toner 4 or the like retained in the retained portion. The toner 4 having a large particle size cannot move any further and is removed from the surface of the photoconductor 21. On the other hand, the toner 4 having a smaller particle diameter than the toner 4 which has accumulated in the accumulating portion is accumulated. The toner 4 and the like which have been pushed forward are retained while being pushed out from the staying portion, and the pushed-out toner 4 and the like are removed from the surface of the photoconductor 21.

Next, the cleaning blade 28 is brought into pressure contact with the surface of the photoconductor 21 for inspection at a pressure contact angle of 14
The pressure contact force for adjusting the end of the cleaning blade 28 against the surface of the photoconductor 21 for inspection is adjusted to 1.5 g / mm, 2.0 g / mm, 3.0.
It is adjusted to g / mm, and the state in which the fluidizing agent 4a, the toner 4 and the like are retained in the retaining portion S is examined, and the length (L ₁ ) of the portion in which the fluidizing agent 4a is retained and this flowability Agent 4a
And the total length of the portion where the toner 4 and the like stay (L
₂ ) was measured and the results are shown in Table 1 below.

[0059]

[Table 1]

The length (L ₁ ) of the portion where the fluidizing agent 4a is retained and the entire length (L ₂ ) of the portion where the fluidizing agent 4a and the toner 4 and the like are retained are shown above. The cleaning performance was evaluated when cleaning was performed with the above adjustments, and the results are shown in Table 2 below. In addition, in the table, when there is no unwiping, it is good.
When there is a small amount of unwiped material but there is no problem, Δ is shown, and when there is a problem with unwiped material, it is shown with x, and the cleaning blade 28 vibrates due to friction with the photoconductor 21 and emits a sound. When it did, it was displayed as a squeal.

[0061]

[Table 2]

Next, a commercially available electrophotographic copying machine (Di30 manufactured by Minolta Co., Ltd.) was remodeled, and the contact angle and contact force of the cleaning blade with respect to the photosensitive member were determined by the length of the portion where the fluidizing agent 4a was retained. (L ₁ ) is in the range of 5 to 50 μm, and the length (L ₂ ) of the entire portion where the fluidizing agent 4a and the toner 4 and the like are retained is set in the range of 10 to 100 μm. When the above-mentioned developer is supplied to the developing device in this electrophotographic copying machine to form an image, image noise due to poor cleaning does not occur in the formed image, and the cleaning blade is a photosensitive member. It is possible to obtain high-definition and good images stably over a long period of time without vibrating and making noise due to friction with Became.

[0063]

As described above in detail, in the image forming method of the present invention, the end portion of the residual material such as toner remaining on the surface of the photoconductor is brought into contact with the surface of the photoconductor as described above. Since the cleaning blade is used to remove the toner, the toner can be removed well from the surface of the photoconductor even when a toner having a small volume average particle diameter of 3 to 9 μm and a spherical shape is used. Image noise due to poor cleaning does not occur, and the friction between the cleaning blade and the photoconductor rarely wears them, and the cleaning blade vibrates due to the friction with the photoconductor to produce a noise. There is no need to make a call or turn up,
It has become possible to stably obtain high-definition and good images over a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram showing a state in which an image is formed by an image forming apparatus using an electrophotographic method.

FIG. 2 is a partial explanatory view showing a state in which a cleaning blade is brought into contact with the surface of the photoconductor.

FIG. 3 is a schematic diagram of an experimental apparatus used to inspect a state in which toner and the like are removed from the surface of the photoconductor by the cleaning blade in the experimental example.

FIG. 4 is a schematic explanatory view showing a state in which residues such as a fluidizing agent and toner are retained in a wedge-shaped retention portion on the upstream side in the moving direction of the photoconductor with respect to a portion where the end of the cleaning blade is in contact. .

[Explanation of symbols]

 1, 21 Photoreceptor 3, 23 Developing device 4 Toner 4a Fluidizing agent 6 Transfer material 8a, 28 Cleaning blade S Stagnation part

Claims (1)

[Claims] 1. An electrostatic latent image formed on a moving photoconductor is developed with a developer containing toner to form a toner image on the surface of the photoconductor, and the toner image is transferred onto a transfer material. In the image forming method, the end of a cleaning blade made of an elastic member is brought into contact with the surface of the photoconductor to remove the residue such as toner remaining on the surface of the photoconductor. A spherical toner having a volume average particle size of 3 to 9 μm and a BET specific surface area of 30 to 300 m ² /
g of a fluidizing agent is used, and a wedge-shaped material is formed between the cleaning blade and the surface of the photoconductor on the upstream side in the moving direction of the photoconductor from the portion where the end of the cleaning blade contacts. Residues such as toner are retained in the retention portion, and the fluidizing agent is added to the retention portion from the portion where the end portion of the cleaning blade and the photosensitive member come into contact with each other 5 to 5
An image forming method, characterized in that a residue such as a toner remaining on the surface of a photoconductor is removed in a state of staying in a range of 0 μm.