JP2002040800A - Toner carrier and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner carrier and an image forming device using the toner carrier by which toner damage is restrained and an excellent image is stably obtained in service environment where an image defect is easily caused such as in the case of long-term storage or long-term use. SOLUTION: This toner carrier forms a visible image by carrying toner on its surface, forming a toner thin film and supplying the toner to the surface of an image forming body in contact with or proximately to the image forming body in such a state. In the toner carrier and the image forming device constituted by attaching the toner carrier, the value of Z shown by an expression (1) Z=We/(We+Wr) obtained from the deformation recovery behavior of the surface of the toner carrier is >=0.70 in the case of measuring the universal hardness of the surface of the toner carrier (in the expression, We means the elastic energy of energy concerning the deformation of the surface obtained from the deformation recovery behavior of the surface of the toner carrier in the case of measuring the universal hardness of the surface of the toner carrier, and Wr means the plastic energy thereof.).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a toner carrier and an image forming apparatus using the same. For more information,
The present invention relates to a toner for forming a visible image on a surface of an image forming body by supplying toner to an image forming body such as a photoconductor or paper holding an electrostatic latent image in an image forming apparatus such as a copying machine or a printer. TECHNICAL FIELD The present invention relates to a toner carrier that provides a high-quality image without image unevenness, has a small characteristic change during long-term use, and has excellent durability, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming method such as a copying machine or a printer, a one-component toner is supplied to an image forming body such as a photosensitive member holding an electrostatic latent image, and the toner is supplied to the latent image. A pressure development method is known as an image forming method for visualizing the toner by adhering it to U.S. Pat.
No. 3,731,146). This pressure development method,
An image is formed by bringing a toner carrying member carrying a toner into contact with an image forming body (a photoreceptor or the like) holding an electrostatic latent image and attaching the toner to the latent image of the image forming body. Therefore, it is necessary to form the toner carrier from a conductive elastic body having conductivity and elasticity.

That is, in the above-described pressure developing method, for example, as shown in FIG. 2, a toner applying roller 5 for supplying toner and an image forming body (photosensitive material or the like) holding an electrostatic latent image are provided. 6), a toner carrier (development roller) 1 is provided, and the toner carrier (development roller) 1,
The image forming body (photoreceptor or the like) 6 and the toner applying roller 5 rotate in the directions indicated by the arrows in FIG.
Is supplied to the surface of the toner carrier (developing roller) 1 by the toner application roller 5, and the toner is
When the toner carrier (developing roller) 1 is rotated while being in contact with the image forming body (photoreceptor or the like) 6 in a state where the toner carrier is developed into a uniform thin film, the toner formed on the thin film is transferred to the toner carrier (developing roller). ) 1 to image forming body (photoconductor etc.)
6 so as to adhere to the latent image and visualize the latent image.

In such an image forming apparatus using the pressure development method, the toner carrier 1 must rotate while maintaining a state in which the toner carrier 1 is in close contact with the image forming body 6.
For example, as shown in the schematic cross-sectional view of FIG. 1, an elastic rubber such as silicone rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, polyurethane rubber, foam, or the like is formed on the outer periphery of a shaft 2 made of a good conductive material such as metal. It has a structure in which a conductive elastic layer 3 made of a conductive elastic body provided with conductivity by blending a conductive agent is formed.
Further, a coating layer 4 made of a resin or the like is provided for controlling the chargeability and adhesion of the toner, controlling the frictional force between the image forming body and the laminating blade, and preventing contamination of the image forming body by the elastic body. It is provided on the surface of the conductive elastic layer 3.

On the other hand, an image forming method for forming an image by directly flying toner carried on a toner carrier through a hole-shaped control electrode on an image forming body made of paper such as paper or OHP paper. Has also been proposed. In addition, a thin layer of non-magnetic toner is carried on the surface of a sleeve-like toner carrier disposed in a non-contact state in proximity to the photoconductor, and the non-magnetic toner is developed by flying over the photoconductor. A method for forming an image has also been proposed (Japanese Patent Application Laid-Open No. 58-116559). In either of the above two methods, on the toner carrier, to control the chargeability and adhesion to the toner, or to reduce the frictional force with other members such as a photoconductor, a layered blade, and a control electrode, A coating layer made of resin or the like is provided on the surface of the conductive elastic layer. The present inventors have proposed that a toner carrier using each resin such as a melamine resin, a phenol resin, an alkyd resin, a fluororesin, and a polyamide resin for a coating layer can improve friction and image characteristics. Was.

[0006]

However, in recent years,
Speed up printers, improve required image fineness,
Alternatively, due to color image formation and the like, requirements for image forming properties have become severe, and various problems that cannot be dealt with by a conventional toner carrier have become apparent. In particular, an increase in toner damage due to speeding up is regarded as a serious problem that leads to image defects such as fogging due to poor toner charging when the toner carrier is used for a long time. In addition, regarding the durability of the toner carrier, the toner mass which has been filmed or melted and fixed due to the toner damage grinds and wears the toner carrier or a contact part with the toner carrier, thereby causing toner leakage. And other problems.

[0007] Although appropriate removal of the damaged toner is a drastic solution to various problems caused by toner damage, it is difficult to completely remove the damaged toner from the developing system with the current technology. . In such a case, as a countermeasure from the toner carrier side, reducing the hardness of the toner carrier to absorb the contact pressure with other components as much as possible is one effective means for suppressing toner damage. However, on the other hand, if the hardness of the toner carrier is very flexible, such a carrier is incorporated into a printer or the like,
If an image is taken out after being kept in a non-use state for a long period of time, deformation due to pressure contact between the carrier and the stratification blade may remain in the halftone image, and a streak-like mark (set image failure) may occur. It has been known. From this, conversely, by increasing the hardness of the toner carrier as much as possible,
A method of improving the abrasion resistance while limiting the deformation amount due to the pressure contact can be considered, but in such a case, the stress applied to the toner becomes extremely large, and the damaged toner increases. As a result, the charging characteristics of the toner fluctuate, which may have a significant adverse effect on image characteristics.

The present invention has been made under such circumstances. That is, the present invention suppresses toner damage, and at the same time, prevents another adverse effect such as an image defect caused by suppressing the toner damage, and it is said that image defects are likely to occur during long-term storage or long-term use. It is an object of the present invention to provide a toner carrier capable of obtaining a good image stably in a use environment, and an image forming apparatus using the toner carrier.

[0009]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have determined the surface properties of the toner carrier by measuring the deformation recovery behavior of the surface of the toner carrier when measuring the universal hardness. Is adjusted so that the following value Z obtained from the following becomes the value described later, the toner damage is suppressed, the adverse effect caused by the toner damage is prevented, and image defects easily occur during long-term storage or long-term use. It has been found that a good image can be stably obtained in a use environment referred to as "the use environment".

That is, in the universal hardness measurement, a quadrangular pyramid or triangular pyramid-shaped indenter is pushed into an object to be measured while applying a predetermined test load, and the surface area of the indenter in contact with the object to be measured is determined from the depth of the indentation. The universal hardness is determined from the determined surface area and the test load.In this case, after the indenter is pushed into the object to be measured, the load on the indenter is gradually reduced to reduce the deformation of the surface of the object to be measured. The values of the elastic energy and the plastic energy of the energy, and the respective energy ratios can be obtained. The present invention has found that the set image defect can be prevented by controlling the relationship between the elastic energy and the plastic energy to a specific value. It should be noted that the viscoelastic properties near the surface of the toner carrier contribute to the set resistance and the wear resistance of the toner carrier beyond the hardness of the entire toner carrier measured by Asker C hardness or the like. That is. The present invention has been studied to evaluate the viscoelastic properties of the toner carrier surface portion numerically,
It has been found that it can be evaluated by the following Z value obtained by a universal hardness measurement or the like. The present invention has been completed based on such findings.

That is, in the present invention, a toner is supported on the surface to form a thin film of the toner, and in this state, the toner is brought into contact with or close to the image forming body to supply the toner to the surface of the image forming body. When measuring the universal hardness of the surface of the toner carrier for forming an image, the formula (1) Z = We / (We + Wr) (1) obtained from the deformation recovery behavior of the surface of the carrier. In the equation, We represents the elastic energy of the energy related to the deformation of the surface obtained from the deformation recovery behavior of the surface of the toner carrier when measuring the universal hardness of the surface of the toner carrier, and Wr represents the plastic energy thereof. The value of Z shown is 0.70 or more, a toner carrier, a toner carrier, and a toner carrier formed by forming a thin film of toner on the surface. In an image forming apparatus having at least an image forming body formed by forming a visible image formed by toner supplied from the toner carrying body on the surface thereof, the toner carrying body is used as the toner carrying body. Forming apparatus.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. As described above, the present invention optimizes the relationship between the elastic energy and the plastic energy required when measuring the universal hardness of the toner carrier surface, thereby suppressing the plastic deformation of the toner carrier, and The main feature is to prevent set image defects during storage.

The universal hardness is a physical property value obtained by pushing an indenter into a measurement object while applying a load, and is obtained as (test load) / (indenter surface area under test load). Is expressed in N / mm ² . This universal hardness measurement is available from Fischer
The measurement can be performed using a commercially available hardness measuring device such as an ultra-fine hardness meter H-100V (Fisher). In this measuring device, a quadrangular pyramid or triangular pyramid-shaped indenter is pushed into the object to be measured while applying a test load, and when a predetermined indentation depth is reached, the surface area with which the indenter is in contact is determined from the indentation depth. , And the universal hardness is determined from the above equation.

When measuring the universal hardness, the load on the indenter is gradually increased to a predetermined load, and the indenter is pushed into the object to be measured. Among the energies related to the deformation of the object surface, the values of elastic energy and plastic energy, and their energy ratios can be obtained. That is, if the object to be measured is a completely elastic body, the load is increased and the indenter is pushed into the surface of the object to be measured, and then the load of the indenter is reduced and removed. Therefore, the indenter returns to the original position, that is, the position where the indentation depth is zero. Conversely, if the object to be measured is a completely plastic body, even if the load is removed after pushing the indenter,
The surface of the object to be measured remains in a state where the indenter is pushed in, and the indenter does not return to the original position. By utilizing this, the ratio between the elastic energy and the plastic energy of the measured object can be obtained. Furthermore, it is also possible to perform the same measurement while keeping the indentation load constant. In this case, the deformation energy behavior in a state close to an environment where a pressure contact mark occurs between the toner carrier and the layered blade can be obtained, so that it can be particularly suitably used for the measurement in the present invention. According to these methods, it is possible to measure the deformation energy behavior in a very shallow region of the member surface, which cannot be measured by the conventional compression set test.

In the toner carrier of the present invention, the surface of the toner carrier is adjusted so that Z representing the relationship between the elastic energy and the plastic energy is 0.70 or more, preferably 0.75 to 1.00. Is what you do. In this case, the total energy (sum of elastic energy and plastic energy) is
The elastic energy can be calculated from the product of the indentation load and the depth of the indenter, and the elastic energy can be calculated from the product of the load and the return distance (depth) in the recovery process when the indentation load is removed, using a computer or the like.

The conditions for measuring the total energy and the elastic energy are not particularly limited, and can be appropriately set according to the shape of the indenter, the measuring device, and the like. When measurement is performed using 100 V, the following conditions can be exemplified. That is, the indenter is pushed into the surface of the toner carrier under the following conditions, a predetermined load is held for about 60 seconds, the load is removed, and the total energy and elastic energy can be calculated by a computer. Measurement condition example Indenter: Square pyramidal diamond indenter with facing angle of 136 degrees Initial load: 0.02 mN / mm ² Maximum load: 100 to 400 mN / mm ² Load application speed: 100/60 mN / mm ² / sec Maximum load creep time ： 60sec

In the toner carrier of the present invention, the elastic energy and the plastic energy on the surface thereof are expressed by the above formula (1).
The structure and shape are not limited as long as they satisfy the following relationship. Usually, as shown in FIG. 1, the conductive elastic layer 3 having conductivity outside the good conductive shaft 2, The coating layer 4 is formed on the surface. As the shaft 2, any material may be used as long as it has good conductivity. Usually, a metal core such as a metal core or a metal cylinder having a hollow inside is used. A metal shaft is used.

As the conductive elastic layer 3, an elastic body having conductivity by adding a conductive agent to an appropriate rubber material is used. There is no particular limitation on the rubber material that can be used here,
Nitrile rubber, ethylene-propylene rubber, styrene-
Examples thereof include butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, silicone rubber, urethane rubber, acrylic rubber, chloroprene rubber, butyl rubber, and epichlorohydrin rubber. These can be used alone or in combination of two or more. In the present invention,
Of these, ethylene-propylene rubber, butadiene rubber, silicone rubber, and urethane rubber are preferably used. Also, mixtures of these with other rubber materials are preferably used. Particularly, in the present invention, a resin having a urethane bond is preferably used.

The conductive agent added to the conductive elastic layer includes an ionic conductive agent and an electronic conductive agent. As the ion conductive agent, tetraethylammonium, tetrabutylammonium, lauryltrimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium, dodecyltrimethylammonium,
Perchlorates such as hexadecyltrimethylammonium, benzyltrimethylammonium, and modified fatty acid dimethylethylammonium, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates Ammonium salts such as acid salts and sulfonates; perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides of alkali metals or alkaline earth metals such as lithium, sodium, calcium and magnesium Hydrochloride, trifluoromethyl sulfate, sulfonate and the like are exemplified.

Examples of the electron conductive agent include conductive carbon such as Ketjen black and acetylene black;
F, ISAF, HAF, FEF, GPF, SRF, F
Carbon for rubber such as T and MT; carbon for ink subjected to oxidation treatment; pyrolytic carbon, graphite; tin oxide;
Examples thereof include conductive metal oxides such as titanium oxide and zinc oxide; and metals such as nickel and copper. These conductive agents can be used alone or in combination of two or more. In addition, the compounding amount is not particularly limited, but in the case of an ion conductive agent, 0.01 to 5.00 parts by weight, and further 0.05 to 2.00 parts by weight based on 100 parts by weight of the rubber component. In the case of an electronic conductive agent, it is preferably 1.0 to 50,000 parts by weight, and more
It is preferably from 5.00 to 40.00 parts by weight.

In the present invention, the volume resistivity of the conductive elastic layer is adjusted to 10 ³ to 10 ¹⁰ Ω ·
cm, preferably 10 ⁴ to 10 ⁸ Ω · cm. In addition, various additives such as a filler, a cross-linking agent, and other additives for rubber can be appropriately compounded in the conductive elastic layer in addition to the conductive agent, if necessary. Since the conductive elastic layer is used in contact with an image forming body, a layered blade, or the like, it is preferable that the compression set is small, specifically, 20% or less, more preferably 10% or less. preferable. It is preferable to use polyurethane rubber as the rubber material because the compression set can be designed to be small.

In the present invention, the surface roughness of the conductive elastic layer is 1 to 20 μm Rz in terms of JIS 10-point average roughness,
Further, the thickness is preferably 1.5 to 18 μmRz. If the average roughness is more than 20 μmRz, it is necessary to form a thick coating layer of the toner carrier, so that the surface of the toner carrier becomes hard. As a result, the toner is damaged, and the toner adheres to the image forming body or the layered blade. Etc. may occur to cause image defects. On the other hand, when the average roughness is smaller than 1 μmRz, the average roughness of the surface of the toner carrier becomes too small when the coating layer is formed, and the toner carrying amount is reduced, so that the image density may be reduced. In the present invention, the surface roughness is measured using a surface roughness meter “Surfcom 59”.
0A "(manufactured by Tokyo Seimitsu Co., Ltd.), measuring length 2.4 mm, measuring speed 0.3 mm / sec in a direction perpendicular to the axial direction.
c, a value obtained by measuring at 300 or more locations so that there is no deviation in the shaft direction and circumferential direction of the roller at a cutoff wavelength of 0.8 mm. (The same applies hereinafter)

In the toner carrier of the present invention, the control of the chargeability and adhesion to the toner, the reduction of the frictional force with the image forming body and the layered blade, or the prevention of contamination of the image forming body by the elastic body. Therefore, it is preferable to provide a coating layer made of resin or the like on the surface of the conductive elastic layer. The coating layer has a glass transition point of 10 ° C. or lower, particularly -5 to 0.
It is preferable to use a material containing a resin at a temperature of ° C. When a resin having a glass transition point exceeding 10 ° C. is used, the physical properties of the coating layer may fluctuate greatly depending on the use environment temperature, and the amount of toner transported and the amount of charge may vary. It becomes brittle, cannot follow the deformation of the conductive elastic layer, and has a problem that the coating layer is easily broken.

The above coating layer has a dynamic elastic modulus E ′ of 10
⁷ to ^109.8 dyn / cm ² , further 10 ⁸ to ^109.6 d
yn / cm ² and a loss tangent ta.
nδ is preferably 0.7 or less, more preferably 0.05 to 0.5. Here, the loss tangent indicates the ratio of the dynamic loss E ″ to the dynamic elastic modulus E ′ when stress is applied to the sample. Solvent (a good solvent such as acetone) for the coating layer
Those having an insoluble content of 70% by weight or more are preferably used. If the solvent-insoluble content is less than 70% by weight, a single molecular weight shift occurs in the press-contact portion of another member that is in contact with the toner carrier such as an image forming body or a layered blade due to long-term storage, and a black horizontal line or the like appears on the image. There is a possibility that the malfunction of the above will occur. From such a point, it is particularly preferable that the solvent-insoluble content is 80% by weight or more.

In the present invention, as a resin that can be used for forming the above-mentioned coating layer, a crosslinkable resin and the like are preferably mentioned. Here, the crosslinkable resin refers to a resin that is self-crosslinked by heat, a catalyst, air (oxygen), moisture (water), an electron beam, or the like, or a resin that is crosslinked by a reaction with a crosslinking agent or another crosslinkable resin. Examples of such a crosslinkable resin include a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group,
Fluororesins, polyamide resins, acrylic urethane resins, alkyd resins, phenolic resins, melamine resins, which have reactive groups such as imino groups, isocyanate groups, methylol groups, alkoxymethyl groups, aldehyde groups, mercapto groups, epoxy groups, and unsaturated groups. Silicone resin, polyurethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, polyether resin, amino resin, urea resin, acrylic resin, acrylic-modified silicone resin,
Styrene-butadiene resins and mixtures thereof.

In the present invention, among these, fluorine resin, polyamide resin, acrylic urethane resin, alkyd resin, phenol resin, melamine resin, silicone resin, polyurethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, acrylic resin , Acrylic-modified silicone resin, styrene-butadiene resin and mixtures thereof are preferably used, and in particular, fluorine resin, polyamide resin, alkyd resin, phenol resin, melamine resin, silicone resin, polyurethane resin, polyester resin, acrylic resin, acrylic modified Silicone resin, styrene-butadiene resin or a mixture thereof is preferred from the viewpoints of toner charging ability, non-staining property for toner, reduction of frictional force with other members, non-staining property for image forming body, and the like. That. Also, mixtures of these with other resins can be used.

Examples of the catalyst used for the crosslinking include radical catalysts such as peroxides and azo compounds, acid catalysts, and the like.
Basic catalysts and the like can be mentioned. As the crosslinking agent, a reactive group such as a hydroxyl group, a carboxyl group, an acid anhydride group, an amino group, an imino group, an isocyanate group, a methylol group, an alkoxymethyl group, an aldehyde group, a mercapto group, an epoxy group, and an unsaturated group. Molecular weight of 10 or more in one molecule
It is a compound having a molecular weight of 00 or less, preferably 500 or less, and examples thereof include a polyol compound, a polyisocyanate compound, a polyaldehyde compound, a polyamine compound, and a polyepoxy compound.

The coating layer in the present invention comprises the above resin as a main component, and further improves the chargeability of the toner.
Various additives such as a charge control agent, a lubricant, and other resins can be blended for the purpose of reducing frictional force with other members, imparting conductivity, and the like. In the carrier of the present invention, the volume resistivity of at least the outermost layer of the coating layer is preferably set to a value higher than the volume resistivity of the conductive elastic layer in order to adjust the resistance of the toner carrier. Typically, the volume resistivity of the outermost layer is 10 ⁷ to 10 ¹⁶ Ω · cm,
It is preferably set to ¹⁰ to 10 ¹³ Ω · cm. The volume resistance can be adjusted by adding an ionic conductive agent or an electronic conductive agent to the cured resin. As the kind of the conductive agent, any conductive agent used in the conductive elastic layer can be used.

The volume resistivity of the toner carrier of the present invention is 10
It is preferably ⁶ to 10 ¹² Ω · cm, more preferably 10 ⁷ to 10 ¹⁰ Ω · cm. The surface roughness of the toner carrier on which the coating layer was formed was JIS 10 point average roughness of 20 μm.
Rz or less, 1-20 μmRz, especially 1-15 μmR
z is preferable. If the average roughness is more than 20.0 μmRz, the charge amount of the toner may be small, or the toner may be oppositely charged, resulting in image fog. If the average roughness is too small, the amount of toner carried becomes small, and the image density may be reduced. There is no particular limitation on the method of forming the coating layer, but usually, a coating liquid formed by dissolving or dispersing the above-described resin forming the coating layer, a crosslinking agent and various additives as necessary, After coating on the conductive elastic layer by a dipping method, a roll coater method, a doctor blade method, a spray method, or the like, at room temperature or 50 to 170
It is formed by drying and curing at a high temperature of ℃.

Solvents used for preparing the coating liquid used for forming the above coating layer include alcohol solvents such as methanol, ethanol, isopropanol and butanol; ketone solvents such as acetone, methyl ethyl ketone and cyclohexane; toluene and xylene Aromatic hydrocarbon solvents such as hexane; Aliphatic hydrocarbon solvents such as cyclohexane; Ester solvents such as ethyl acetate; Ether solvents such as isopropyl ether and tetrahydrofuran; Amide solvents such as amides; halogenated hydrocarbon solvents such as chloroform and dichloroethane and the like or a mixed solvent thereof are preferably used. The solvent may be appropriately selected depending on the solubility of the resin used, and is not particularly limited.

The thickness of the coating layer is preferably 1 to 50 μm, particularly preferably 2 to 30 μm. When the thickness of the coating layer is thinner than the above range, local discharge occurs, and horizontal white lines are easily generated in the image. When the thickness is larger than the above range, the toner carrier becomes hard and damages the toner, and the image forming body is damaged. Or toner adhesion to the layering blade or the like may occur, resulting in image failure. The hardness of the toner carrier of the present invention is generally 35 to 85 degrees, particularly 37 to 80 degrees for Asker C type. When the hardness exceeds 85 degrees, the toner carrier becomes hard, the contact area with the image forming body or the like becomes small, and there is a possibility that good image formation may not be performed. In some cases, toner sticking to the blade or the like occurs, causing image defects. On the other hand, if the hardness is too low, the friction with the image forming body or the stratification blade becomes large, and image defects such as jitter may occur.

The main feature of the present invention is to optimize the relationship between the elastic energy and the plastic energy in the vicinity of the surface of the toner carrier. Further, the Asker C hardness on the surface becomes 50 to 80 degrees. It is preferable that it is adjusted as described above. That is, when the Asker C hardness is lower than 50 degrees, it is difficult to adjust the Z value within the range of the Z value in a material system suitable for a toner carrier. This is because when the hardness of the entire toner carrier is extremely deviated from the appropriate region and becomes low, the effect of the flexibility of the entire toner carrier becomes apparent beyond the contribution of the viscoelastic properties near the surface of the toner carrier, and macroscopically. This is presumed to be due to the occurrence of severe plastic deformation.

The toner carrier of the present invention is used as a toner carrier such as a developing roller in an image forming apparatus such as a developing device in an electrophotographic apparatus.
As shown in FIG. 1, a toner carrier of the present invention is disposed as a developing roller 1 between a toner applying roller 5 for supplying toner and an image forming body 6 such as a photosensitive drum holding an electrostatic latent image. The toner 7 is carried by the roller 5 for applying toner, and the toner 7 is formed into a uniform thin layer by the layering blade 8.
Further, the toner is supplied from the thin layer to the image forming body 6, and the toner is attached to the electrostatic latent image of the image forming body 6 to visualize the latent image.

In the image forming apparatus using the toner carrier of the present invention, a toner carrier which carries a toner on the surface to form a thin layer of the toner and forms a visible image on the image carrier in this state. Any type of image forming apparatus may be used as long as the image forming apparatus includes a paper body, such as paper or OHP paper, and the toner carried on the toner carrier is formed on the control electrode. The image may be directly formed on paper or OHP paper by directly flying through the hole. As the toner carried on the toner carrier of the present invention, a non-magnetic one-component developer is preferably used, but a magnetic-type one-component developer can also be used. The toner carrier and the image forming apparatus of the present invention can be suitably used also when performing black-and-white image printing using the same.

[0035]

EXAMPLES The present invention will now be described specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 Polyether polyol having a molecular weight of 5000 (OH value: 3)
3) To 100 parts (parts by weight, hereinafter the same), 1.0 part of 1,4-butanediol, 0.5 part of nickel acetylacetonate
, 0.01 parts of dibutyltin dilaurate and 2.0 parts of acetylene black were added and mixed using a mixer to prepare a polyol composition. After stirring and defoaming the polyol composition under reduced pressure, 17.5 parts of urethane-modified MDI was added, and the mixture was stirred for 2 minutes.
It was poured into a mold heated to 10 ° C. and cured at 110 ° C. for 2 hours to form a conductive elastic body on the outer periphery of the metal shaft to obtain a roller. Polish the surface of the obtained roller to make the surface J
The IS 10 point average roughness was adjusted to 15.0 μmRz. In addition,
The surface roughness was measured using a surface roughness meter Surfcom 590A (manufactured by Tokyo Seimitsu Co., Ltd.) (the same applies in the following examples).

Next, the alcohol-soluble resol type phenol solution was diluted with ethanol as a solvent to prepare a coating material having a total solid content of 15%. In the coating liquid,
The conductive elastic roller is immersed and pulled up.
FIG. 1 having a coating layer cured by heating at 10 ° C. for 4 hours
The same roller-shaped toner carrier as shown in (1) was obtained. The dynamic elastic modulus E ′, loss tangent tan δ, insolubility in solvent, thickness, and JIS 10-point average roughness Rz of the toner carrier of the obtained coating layer are shown in Table 1 below. Asker C hardness on the surface of the obtained toner carrier was 63.0 degrees.
Further, using a ultra-fine hardness tester H-100V manufactured by Fischer, a load was applied and removed under the following measurement conditions to examine the deformation energy behavior of the surface. The Z value was 0.936.
It was 3. Measurement conditions indenter: quadrangular pyramid-type diamond indenter initial load of facing angle 136 °: 0.02mN / mm ² Maximum Load: 100 mN / mm ² load application ^{rate: 100 / 60mN / mm 2 /} sec maximum load at creep time: 60 sec

The toner carrier is used as a developing roller.
In the developing unit shown in FIG.
V, blade bias -600V, average particle size 7μm
With a linear speed of 60 mm /
An image was formed by reversal development while rotating at a peripheral speed of sec, and image evaluation was performed on a white background, a halftone image, and a black background image. Each of the initial image and the durable image was evaluated for a total of five images to determine the tendency. 4% continuous printing 1 as a durable image
The printed image after the completion of 10,000 copies was used (printing conditions and evaluation method are the same in the following examples). As a result, good printing results were obtained for each image. Further, with the toner carrier being incorporated in a printer as a developing roller, the printer was allowed to stand for 1 week in an environment at a temperature of 22.5 ° C. and a humidity of 50%, and then a halftone image was printed. Did not occur.

Example 2 A roller composition was prepared under the same conditions as in Example 1 except that the amount of 1,4-butanediol added was 10 parts and the amount of urethane-modified MDI was 20 parts in the polyol composition. I got Next, acetylene black was added as a conductive agent to the polyether polyurethane resin solution to adjust the volume resistivity at the time of film formation to 1.08 × 10 ⁸ Ω · cm. Created. The conductive elastic roller was immersed in the coating liquid, pulled up, and air-dried at 100 ° C. for 30 minutes. Further, an oil-free alkyd compound and an iso-butyl ether melamine resin were blended so as to have a solid content weight ratio of 75/25, and further diluted with methyl ethyl ketone as a solvent to newly prepare a paint having a total solid content of 15%. . After the above-mentioned air-dried conductive elastic roller is returned to room temperature, it is dipped in the paint and pulled up, heated at 110 ° C. for 4 hours, and has a cured coating layer. A toner carrier in the form of a toner was obtained. The dynamic elastic modulus E ′, loss tangent tan δ, insolubility in solvent, thickness, and JIS 10-point average roughness Rz of the toner carrier of the obtained coating layer are shown in Table 1 below.

The Asker C hardness on the surface of the obtained toner carrier was 64.0 degrees. When the deformation energy behavior of the surface was examined, the Z value was 0.8993. Using the toner carrier as a developing roller, image evaluation was performed on a white background, a halftone image, and a black background image. As a result, good printing results were obtained for each image. 1
After the endurance printing of 10,000 sheets, no streak-like abrasion occurred on the toner carrier, and no toner leakage occurred. Further, with the toner carrier being incorporated in a printer as a developing roller, the apparatus was allowed to stand for one week in an environment of a temperature of 22.5 ° C. and a humidity of 50%, and then a halftone image was printed. Did not occur.

Comparative Example 1 In the polyol composition, a polyalkylene polyol having a molecular weight of 5500 (OH value: 28) was used instead of the polyether polyol having a molecular weight of 5000, and the addition amount of the urethane-modified MDI was changed to 13 parts. Example 1
A roller was obtained under the same conditions as described above. Next, by adding acetylene black as a conductive agent to the urethane-modified acrylic compound, the volume resistivity at the time of film formation was 8.08 × 10 ^7.
A paint having a total solid content of 25.0% adjusted to Ω · cm was prepared. The conductive elastic roller was immersed in the coating liquid, pulled up, and heated at 130 ° C. for 4 hours to obtain a roller-shaped toner carrier similar to that shown in FIG. 1 having a cured coating layer. . The dynamic elastic modulus E ′, loss tangent tan δ, insolubility in solvent, thickness, and JIS 10-point average roughness Rz of the toner carrier of the obtained coating layer are shown in Table 1 below.

The Asker C hardness on the surface of the obtained toner carrier was 60.5 degrees. When the deformation energy behavior of the surface was examined, the Z value was 0.5500. Using the toner carrier as a developing roller, image evaluation was performed on a white background, a halftone image, and a black background image. As a result, a good printing result could be obtained in the initial image, but fog occurred in the white background printing in the durable image.
Further, after the endurance printing of 10,000 sheets, streak-like abrasion occurred on the toner carrier, and toner leakage occurred.

Comparative Example 2 In the polyol composition, a polyalkyd polyol having a molecular weight of 6000 (OH value: 30) was used in place of the polyether polyol having a molecular weight of 5000, and a urethane-modified M
A roller was obtained under the same conditions as in Example 1 except that DI was hydrogenated MDI. Then, by adding acetylene black as a conductive agent to the polyether polyurethane resin solution, the volume resistivity at the time of film formation was 1.08 × 10 ⁸ Ω · c.
m having the coating layer cured and heat-treated on the same roller under the same conditions as in Example 2 except that the total solid content of the paint adjusted to m was 15.0%. A similar roller-shaped toner carrier was obtained. The dynamic elastic modulus E ′, loss tangent tan δ, insolubility in solvent, thickness, and JIS 10-point average roughness Rz of the toner carrier of the obtained coating layer are shown in Table 1 below.

The Asker C hardness on the surface of the obtained toner carrier was 63.0 degrees. Further, when the deformation energy behavior of the surface was examined, the Z value was 0.6011. Using the toner carrier as a developing roller, image evaluation was performed on a white background, a halftone image, and a black background image. As a result, good printing results were obtained for each image,
After the endurance printing of 10,000 sheets, streak-like abrasion occurred on the toner carrier, and toner leakage occurred. When the toner carrier was incorporated in a printer as a developing roller and left for 1 week in an environment at a temperature of 22.5 ° C. and a humidity of 50%, a halftone image was printed. A streak-like image defect occurred.

[0044]

[Table 1]

[0045]

As described in detail above, the toner carrier of the present invention suppresses toner damage by optimizing the relationship between the elastic energy and the plastic energy near the surface of the toner carrier. It is possible to prevent another adverse effect such as an image defect caused by toner damage suppression, and to obtain a stable and good image in a use environment where image defects are likely to occur conventionally, such as during long-term storage and long-term use. It can be used as a toner carrier of various image forming apparatuses.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a toner carrier of the present invention.

FIG. 2 is a schematic sectional view showing an example of the image forming apparatus of the present invention.

[Explanation of symbols]

 1: toner carrier 2: shaft 3: conductive elastic layer 4: coating layer 5: toner applying roller 6: image forming body (photoconductor) 7: toner 8: layering blade 9: transfer unit 10: cleaning unit 11: Cleaning blade

 ──────────────────────────────────────────────────の Continued on front page (72) Inventor Takao Ouchi 3-22-8 Midorigaoka, Hamura-shi, Tokyo F-term (reference) 2H077 AD06 EA15 EA16 FA01 FA13 FA22 3J103 AA02 AA14 AA36 AA51 AA85 FA30 GA57 GA58 HA03 HA04 HA12 HA20 HA41 HA43 HA45 HA46 HA47 HA48 HA53

Claims (13)

[Claims] A toner is carried on the surface to form a thin film of the toner, and in this state, the toner contacts or approaches the image forming body,
In a toner carrier that forms a visible image by supplying a toner to the surface of the image forming body, when measuring the universal hardness of the surface of the carrier, the following equation (1) is obtained from the deformation recovery behavior of the surface. We / (We + Wr) (1) (where We is the elastic energy of the surface deformation energy obtained from the deformation recovery behavior of the toner carrier surface when measuring the universal hardness of the toner carrier surface) And Wr represents the plastic energy of the toner carrier.). 2. An Asker C hardness of 50 to 8 on the surface.
The toner carrier according to claim 1, wherein the angle is 0 degree. 3. The toner carrier according to claim 1, comprising an elastic layer and at least one coating layer provided on a surface of the elastic layer. 4. An elastic layer comprising: an ethylene-propylene rubber;
2. A rubber composition comprising butadiene rubber, silicone rubber, urethane rubber or a mixture of these with other rubber materials.
4. The toner carrier according to any one of claims 1 to 3. 5. The toner carrier according to claim 1, wherein the elastic layer contains a resin having a urethane bond. 6. The toner carrier according to claim 1, wherein the coating layer is made of a resin having a glass transition point of 10 ° C. or lower. 7. A coating layer having a dynamic elastic modulus E ′ of 10 ⁷ to 10
^9.8 dyn / cm ² and loss tangent tan δ is
The toner carrier according to claim 1, wherein the number is 7 or less. 8. The toner carrier according to claim 1, wherein the coating layer has an insolubility in a solvent of 70% by weight or more. 9. At least the outermost layer of the coating layer has a thickness of 10 ⁷ to
The toner carrier according to claim 1, having a volume resistivity of 10 ¹⁶ Ω · cm. 10. A method according to claim 1, wherein at least one of the coating layers comprises a fluorine resin, a polyamide resin, an alkyd resin, a phenol resin, a melamine resin, a silicone resin, a polyurethane resin, a polyester resin, an acrylic resin, an acryl-modified silicone resin, a styrene-butadiene resin, The toner carrier according to any one of claims 1 to 9, comprising a mixture of these or a mixture of these and another resin. 11. The toner carrier according to claim 1, wherein the thickness of the coating layer is 1 to 50 μm. 12. The surface roughness is JIS 10 point average roughness of 1 to 10.
The toner carrier according to claim 1, wherein the toner carrier has a thickness of 20 μmRz. 13. An image formed by forming a visible image on the surface of a toner carrier and a toner supplied from the toner carrier in contact with or close to the toner carrier having a thin film of toner formed on the surface. An image forming apparatus having at least a formed body, wherein the toner carrier is used as the toner carrier.
2. An image forming apparatus using the toner carrier according to any one of 2.