JP2001312136A - Toner carrier and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner carrier which is capable of preventing the generation of after-images by imparting excellent negative electrostatic chargeability to toners or with which high-quality images ameliorated in surface staining is obtained and a method for manufacturing such toner carrier. SOLUTION: This toner carrier is formed by incorporating a quaternary ammonium base-containing copolymer into at least a material constituting its surface and is used to subject the toners supplied to the surface to development of an electrostatic latent image. This method for manufacturing the toner carrier consists in forming at least its surface part by using a coating liquid prepared by dissolving or dispersing the material containing at least the quaternary ammonium base-containing copolymer into a solvent mixture composed of an aromatic system and an alcohol system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner carrier in electrophotography, in particular, a one-component toner supplied to the surface thereof is formed into a uniform thin layer by a toner layer thickness regulating member, and this toner is used as an electrostatic latent image. The present invention relates to a toner carrier for use in development and a method for producing the same.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electronic copying machine, a printer, and a facsimile, which forms an electrostatic latent image on an electrostatic latent image holding member and visualizes the electrostatic latent image with a developer to obtain a recorded image, a powdery image is formed. Dry developing devices using a developer are widely used. As such a powdery developer, there are a two-component developer having a toner and a carrier, and a one-component developer without a carrier, and the former two-component developing method using the two-component developer includes: Although a relatively stable and good image can be obtained, there is a disadvantage that the carrier is easily deteriorated and the mixing ratio between the toner and the carrier is easily changed, and the maintenance of the apparatus is complicated, and the structure of the entire apparatus is easily enlarged. ing.

[0003] From such a viewpoint, a one-component developing method using a one-component developer which does not have the above-mentioned disadvantages has attracted attention. The one-component developer includes a toner composed of only a toner, a toner to which an auxiliary agent is externally added as needed, and a toner in which an auxiliary agent is mixed. As the toner, there are a magnetic toner in which magnetic powder is kneaded in each toner particle itself and a non-magnetic toner containing no magnetic powder. Here, since the magnetic material is generally opaque, if a color image including full-color or multi-color is formed by magnetic toner, the developed visible image becomes unclear and a vivid color image cannot be obtained. Therefore, it is desirable to adopt a one-component developing method using a non-magnetic toner especially for color development. As a typical method of developing an electrostatic latent image using a non-magnetic one-component toner, the toner on the toner carrier is uniformly charged with a layer thickness regulating member or the like, is thinned, and the electrostatic latent image carrier, that is, In addition, a method of performing development in a region facing a photoconductor is known. At this time, the toner is charged mainly by a rubbing action with the surface of the toner carrier, and the toner has a predetermined amount of charge of a predetermined polarity. The charge amount of the toner is required to be about -20 ± 5 μc / g in order to obtain a high quality image.

In order to further improve the image quality, there are the following problems to be solved and their solutions. Background Smearing Narrowing the toner charge distribution, especially reducing the amount of toner charged in the opposite direction, can reduce background smear and is important for high image quality. Afterimage A counter charge having a polarity opposite to that of the toner is generated near the surface of the toner carrier. If the toner on the surface of the toner carrier is consumed by development or the like and the opposite charge remains as it is, the toner carrier is not initialized, and the history of the charge and development process in the next rotation remains as an afterimage. There's a problem. In order to solve this problem, a method of reducing the resistance of the toner carrier and quickly eliminating the opposing charge has been adopted, and many resistance control methods have been proposed. The most commonly used method is to add conductive particles such as carbon black, graphite, metal oxides, etc. (for example, JP-A-2-100973 and JP-A-2-33166). However, there are drawbacks such as variations in the voltage and large voltage dependency. In order to solve these drawbacks, there has been proposed a method of adding an ionic conductive agent (Japanese Patent Application Laid-Open No. 2-198470, Japanese Patent Application Laid-Open No. 3-129368, etc.). There were drawbacks such as seepage. In addition, a polymer conductive agent having improved those disadvantages (for example, Japanese Patent Application Laid-Open Nos.
JP-A-313471, JP-A-7-98539, etc.) Inferior in toner releasability, and when used for a surface layer, toner filming occurs.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to a toner capable of imparting excellent negative chargeability to a toner and reducing the resistance to prevent occurrence of an afterimage or to obtain a high-quality image with improved background smear. An object of the present invention is to provide a carrier and a method for producing the carrier.

[0006]

According to a first aspect of the present invention, there is provided a toner comprising an electrostatic latent image, wherein at least the material constituting the surface comprises a quaternary ammonium base-containing copolymer. In the toner carrier for use in the development. In the toner carrier, the toner supplied to the surface is formed into a uniform thin layer by a toner layer thickness regulating member, and the toner is used for developing an electrostatic latent image. A second aspect of the present invention is that the content of the quaternary ammonium salt group-containing copolymer is the first content.
At least 10 to the total weight of the material constituting the surface
50% of the first toner carrier. A third aspect of the present invention resides in the toner carrier according to the first or second aspect, characterized in that at least the material constituting the surface further contains a polyvinyl acetal resin. A fourth aspect of the present invention is to form at least the surface portion of a material containing at least a quaternary ammonium base-containing copolymer by using a coating liquid in which the material is dissolved or dispersed in a mixed solvent of an aromatic and an alcohol. The method for producing a toner carrier according to any one of 1 to 3 above, which is characterized in that:

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic view of a developing device using the toner carrier of the present invention. In FIG. 1, 1 is a container, 2 is a toner, 3 is an agitator, 4 is a replenishing roller, 5 is a toner carrier, 6 is a toner layer thickness regulating member, and 7 is an electrostatic latent image holding member (photoreceptor). I have. The container 1 contains a nonmagnetic one-component toner 2. The toner 2 is conveyed by the agitator 3 to a toner storage section formed by the replenishing roller 4 and the toner carrier 5 and carried on the surface of the toner carrier 5. Further, the toner carried on the surface of the toner carrier 5 forms a uniform thin layer by the toner layer thickness regulating member 6 and is frictionally charged to a predetermined polarity and charge amount. The charge amount of the toner is related to the image quality. If the charge amount is low, the reproducibility of lines and dots is lacking, and a high-quality image cannot be obtained. Usually, -20 ± 5μc for negatively charged toner
/ G is desired. Also, the presence of a so-called oppositely charged toner charged in the opposite direction to the predetermined polarity causes a so-called background stain, which can be measured, for example, by the following method. Using a negatively charged toner in the developing device of FIG. 1, the toner developed on the photoconductor when developed under the electric field conditions of the toner carrier + 400v and the photoconductor 0v is transferred to a tape and attached to a white paper to reduce the image density. Measure. Similarly, a blank is measured, and the difference ΔID is used as a measure of background contamination. Generally, ΔID of 0.04 or less is preferable.

Next, an afterimage will be described. When the toner is held on the toner carrier, a charge having a polarity opposite to that of the toner exists near the surface of the toner carrier. The thin toner layer is carried to a developing area where the electrostatic latent image holder 7 and the toner carrier 5 are in contact with each other, where the toner 2 is electrostatically transferred from the toner carrier 5 to the electrostatic latent image holder 7, The latent image is visualized. Here, opposing charges remain on the toner carrying rod, and the charge elimination speed greatly changes depending on the electric resistance of the material constituting the carrying member. Usually, a volume resistance of about 10 ¹³ Ω · cm or less is required.

Next, the toner carrier according to the present invention will be described. The quaternary ammonium salt group-containing copolymer contained in the toner carrier of the present invention is a quaternary ammonium salt group-containing copolymer comprising a quaternary ammonium salt group-containing maleimide copolymer, a quaternary ammonium salt group-containing methacrylimide copolymer and the like. For example, Japanese Unexamined Patent Publication No.
198308, JP-A-6-271780,
JP-A-6-329923, JP-A-6-17971
No. 6 publication can be used. As typical examples, the following structural formulas (1) and / or
Or what is comprised including what is like (2).

[0010]

Embedded image

[0011]

Embedded image (Wherein, R ₁ is an alkylene group having 2 to 8 carbon atoms, R ₂ and R ₃ are each an alkyl group having 1 to ₄ carbon atoms, R ₄ is an alkyl group having 1 to 12 carbon atoms, and 6 to 12 carbon atoms. Arylalkyl group, carbon number 2 which may be substituted with an alkyl group
An epoxy group or an alicyclic alkyl group having 6 to 12 carbon atoms, R ₅ is a hydrogen atom or a methyl group, X is a halogen atom,
CH ₃ OSO ₃ or C ₂ H ₅ OSO ₃ is shown. m is 0 or 1
Is shown. ) The quaternary ammonium salt group-containing copolymer used in the present invention may be constituted by containing each of the structural formulas (1) and (2) alone or both. Also includes the quaternary ammonium-containing components typified by the structural formula (1) or (2) as one of the structural components, as the copolymerization component to be _{copolymerized,} -CH 2 -CH _(R 1) -
An olefin structural component represented by (R ₁ is, for example, hydrogen or a methyl group), —CH ₂ —CH (COOR ₂ ) — (R ₂
Is, for example, an acrylate represented by an alkyl group having 1 to 4 carbon atoms).

The quaternary ammonium base-containing copolymer used in the present invention has a very good triboelectric chargeability,
It is characterized in that the toner can be given a negative charge by adding a small amount. Further, the quaternary ammonium base-containing copolymer has a very low electric resistance, and the resistance can be easily controlled by adding these resins to other resins. The mechanism by which the resistance decreases is not clear, but it is presumed that the acrylamide structural unit in the resin takes in moisture in the air and the negative counter ion is ionized, indicating electrical conductivity. The addition amount of the quaternary ammonium salt-containing copolymer is preferably from 10 to 50%, more preferably from 15 to 40%, based on the total weight of the material constituting at least the surface. When the addition amount is less than 10%, the volume resistance exceeds 10 ¹³ Ω · cm, and an afterimage is easily generated. Conversely, when the addition amount is more than 50%, the releasability of the toner is poor, and the toner So-called toner filming in which the toner adheres easily occurs.

The quaternary ammonium group-containing copolymer can be mixed with another resin to reduce the resistance of the resin. Examples of the resin that can be mixed include polyolefin resins such as polyethylene and polypropylene,
Acrylic resins, polyester resins, polystyrene resins, ABS resins, polyamide resins, polycarbonate resins, epoxy resins, polyurethanes, polyvinyl acetal resins represented by polyvinyl formal resins and polyvinyl butyral resins are preferred. ,
The one represented by the following structural formula (3) is optimal because of excellent soiling. The polyvinyl acetal-based resin is obtained by condensing aldehyde with polyvinyl alcohol as a raw material. The condensation reaction does not proceed completely, and a part of the alcohol remains and is a random copolymer. These resins may be used alone or in combination of two or more.

[0014]

Embedded image (In the formula, R represents a hydrogen atom, an alkyl group or an aryl group having 1 to about 6 carbon atoms which may have a substituent. X, y
And z represent an arbitrary number of repetitions of the monomer unit.)

The material used for at least the surface of the toner carrier of the present invention may further include silica, calcium carbonate, and the like, in addition to the quaternary ammonium base-containing copolymer and the resin component, if necessary, in order to improve various properties. Inorganic fillers such as calcium oxide, magnesium oxide, zinc oxide, and carbon black; nigrosine dyes; quaternary ammonium salts;
A charge control agent such as a metal-containing azo dye may be contained.
Its content is preferably 5 to 95%, more preferably 30 to 8% of the total weight of the material used for the surface of the toner carrier.
0%. The surface of the toner carrier containing at least the quaternary ammonium group-containing copolymer of the present invention can be formed by a usual processing method, for example, injection molding, extrusion molding and the like. However, when processing by these molding methods, the film thickness is usually about several mm,
It is not suitable for processing a thin layer of about 30 μm. The present invention makes a paint by dissolving a quaternary ammonium salt in a solvent, and enables processing by spraying, dipping, roll-copper or the like. As a result, for example, by applying a thin film on the elastic layer, it is possible to provide an elastic roller having the above-described excellent charging characteristics and electric characteristics.

When a quaternary ammonium salt-containing copolymer is hardly soluble in a solvent and is formed into a coating, a method such as emulsification has been used. However, since a water-based coating is used, other materials are added for the purpose of improving characteristics. For example, there is a problem in the stability of the coating when the coating is performed, and it has been desired to solubilize the coating in some solvent. As a result of various studies, the present inventors have found that a quaternary ammonium salt-containing resin is soluble in a mixed solvent of an aromatic and an alcohol, and it has become possible to form a coating material. That is, the material containing at least the quaternary ammonium base-containing copolymer is formed on the surface by using a coating solution dissolved or dispersed in a mixed solvent of an aromatic and an alcohol. Provided is a method for manufacturing a toner carrier. As the aromatic solvent, toluene and xylene are preferable. As the alcohol solvent, methanol and ethanol are preferable, and a mixed solvent of toluene and methanol is most preferable. The mixing ratio is aromatic solvent / alcohol solvent =
3/7 to 9/1 is preferable, and 5/5 to 8/2 is more preferable.

[0017]

Embodiments of the present invention will be described below. Note that these embodiments are only one embodiment of the present invention, and the present invention is not limited to these embodiments.

Examples 1 to 6 and Comparative Examples 1 to 3 A quaternary ammonium base-containing maleimide resin (Daiichi Kogyo Seiyaku Co., Ltd.) based on 100 parts by weight of high density polyethylene (JALEX A6080A manufactured by Nippon Polyolefin Co., Ltd.) Was mixed and kneaded with a kneader to obtain mixed pellets in the amounts shown in Table 1. This was subjected to roller processing using an injection molding machine, and the surface was polished to obtain a 16φ single-layer toner carrier (layer thickness 3 m).
m). Further, a toner carrier was similarly manufactured using acrylic resin (PMMA) and polycarbonate. Using the obtained toner carrier, the toner charge amount and adhesion amount were measured. Measurement Method The toner carrier was mounted on the developing device shown in FIG. 1, and the toner charge amount (q / m) and the adhesion amount (m / a) after idle rotation for 5 minutes were measured by a suction method. The following members were used. Toner: Ricoh IMAGIO Toner Type 1 Red Supply roller: conductive urethane sponge Blade: 100 μm thick SUS The results are shown in Table 1.

[0019]

[Table 1]

Examples 7 to 12 and Comparative Example 4 Using the polyethylene and quaternary ammonium salt-containing copolymer of Example 1, a toner carrier having the amount shown in FIG. 2 was prepared. The volume resistance of the toner carrier was measured. Measurement method Copper foil tape (manufactured by Sumitomo 3M) is 1 mm on the toner carrier
Wound at three places at intervals, the center tape was used as the main electrode, the core was used as the counter electrode, and the tapes at both ends were used as the guard electrodes.
The v / 1 minute value was measured. Volume resistance (Ω · cm) = (measured value) * 2π (electrode width) /
ln {(diameter of carrier) / (core diameter)} The results are shown in FIG.

Next, the following methods were used to measure the residual image degree of the toner carrier and to perform a toner filming test. Measuring method Image persistence The toner carrier was attached to a Ricoh copier IMAGIO 325T, and a pattern image as shown in FIG. 3 was output to evaluate the image persistence. That is, after the solid black portion is developed, the halftone dots are developed, and the image density of the halftone dot corresponding to the position of the solid black portion (I
DH) and the image density (ID
M) was measured with a Macbeth densitometer and the ratio (DI / I
The residual image was evaluated by DM). In other words, when the ratio is 1, no afterimage is generated and the image quality is good, but the degree of the afterimage deviating from 1 is poor. An afterimage degree of 0.90 or more is an allowable range. Toner filming test The state of the surface of the toner carrier after outputting 10,000 images was evaluated according to the following criteria. Rank A: The toner on the roller surface can be easily removed by air blow. Rank B: A slight amount of toner remains partially due to air blow. Rank C: A thin layer of toner remains because it cannot be completely removed by air blow. Rank D: The toner in the molten state is strongly fixed to the roller surface. Rank B or higher is an allowable range. Table 2 shows the results.

[0022]

[Table 2]

Example 13 The same polyethylene resin as used in Examples 1 to 6,
Acrylic resin, polycarbonate resin and polyvinyl acetal resin as polyvinyl butyral resin (BM-
SZ: Sekisui Chemical Co., Ltd.) and a polyvinyl formal resin (Denka Formal; Electrochemistry) were used to prepare toner carriers in the same manner. The amount (% by weight) of the quaternary ammonium salt-containing resin is shown in Table 3. Using these toner carriers, toners q / m, m / a and ΔID
Was measured. Table 3 shows the results.

[0024]

[Table 3]

Example 14 A paint was prepared by the following method. A quaternary ammonium salt-containing copolymer (Reolex AS170; manufactured by Daiichi Kogyo Seiyaku) was dissolved in a toluene / methanol (7/3 weight ratio) solvent. (10% solid content) Polyvinyl butyral resin (BM-SZ; Sekisui Chemical) was dissolved in toluene / ethanol (1
/ 1 weight ratio) dissolved in a solvent. (5% solids concentration) 25 parts by weight of a quaternary ammonium salt-containing copolymer was mixed with 100 parts by weight of polyvinyl butyral resin, and a conductive urethane rubber (10 ⁵ Ω · cm, layer thickness 4 mm, 16φ) was used.
The surface was spray-coated. After drying at 120 ° C. for 1 hour, the surface was polished to obtain a toner carrier having a surface layer thickness of 20 μm. Using this toner carrier, the toner q
/ M, m / a, ΔID, and toner filming test. Table 4 shows the results.

[0026]

[Table 4] Next, the toner carrier was brought into contact with a 30 mm aluminum base tube (bite amount: 0.5 mm), and the carrier linear velocity was 100 mm.
After spinning at 100 g / sec for 100 hours, the surface of the toner carrier was observed. As a result, no crack was found.

[0027]

According to the present invention, a toner carrier capable of imparting excellent negative chargeability to a toner and preventing the occurrence of an afterimage by lowering the resistance or obtaining a high-quality image with improved background contamination can be obtained. , And a method for manufacturing a toner carrier as described above.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a developing device using a toner carrier of the present invention.

FIG. 2 is a diagram showing a relationship between a quaternary ammonium salt content (%) and a volume resistance (Ω · cm) of a toner carrier prepared using a polyethylene and a quaternary ammonium salt-containing copolymer.

FIG. 3 is a diagram showing a pattern image used for evaluation of image persistence in Examples 7 to 12.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 container 2 toner 3 agitator 4 replenishment roller 5 toner carrier 6 toner layer thickness regulating member 7 electrostatic latent image IDH Image density of halftone dot corresponding to black solid portion IDM Halftone dot other than black solid portion Image density

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 39/04 C08L 39/04 101/00 101/00 F16C 13/00 F16C 13/00 A E F term ( Reference) 2H077 AD06 FA13 3J103 AA02 AA51 FA30 GA02 GA57 GA58 HA41 HA60 4J002 AA011 BB031 BB121 BC021 BE061 BG001 BH012 BH022 BN151 BQ002 CD001 CF001 CG001 CK021 CL001 GH00 GM00 GQ02 HA05 4J100 AAPBC BC01A06P01 BC06A01Q

Claims (4)

[Claims] At least a material constituting a surface contains a copolymer containing a quaternary ammonium salt group. A toner carried on the surface for use in developing an electrostatic latent image is provided. body. 2. The content of the quaternary ammonium salt group-containing copolymer is at least 1 with respect to the total weight of the material constituting the surface.
The toner carrier according to claim 1, wherein the content is 0 to 50%. 3. The toner carrier according to claim 1, wherein at least the material constituting the surface further contains a polyvinyl acetal resin. 4. A coating solution obtained by dissolving or dispersing a material containing at least a quaternary ammonium base-containing copolymer in a mixed solvent of an aromatic type and an alcohol type, wherein at least the surface portion thereof is formed. Claims 1-3
The method for producing a toner carrier according to any one of the above.