JPH08179617A - Developer carrier - Google Patents

Abstract

PURPOSE: To suppress the excessive electrostatic charge of a toner, the fusion of the toner to the top of a developer carrier and the lowering of image density by forming a coating film layer contg. electrically conductive spherical particles and spherical particles which are charged to polarity reverse to that of the toner in a bonding resin on the surface of the developer carrier. CONSTITUTION: A coating film layer 1 contains spherical particles 2 subjected to electric conductive treatment, spherical particles 3 which are charged to polarity reverse to that of a toner and a bonding resin 5 or further contains an electrically conductive substance 4 and/or a solid lubricant 6 if necessary and coats the top of a cylindrical substrate 7. Even if the layer 1 is worn by a long-term durability test (use over a long period of time), the excessive electrostatic charge of a toner and the fusion of the toner to the top of a developer carrier are prevented because the particles 2 are exposed and the electric conductivity of the layer 1 is maintained. Since the toner is subjected to satisfactory electrostatic charge due to the particles 3, satisfactory image density is ensured especially even at high temp. and humidity. Since the particles 3 are spherical, the surface roughness of the layer 1 is uniformly maintained even during a durability test and the transferability of the toner to a developing part is kept uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer carrier used in a developing device for developing and visualizing a latent image formed on an image carrier such as an electrophotographic photoreceptor or an electrostatic recording derivative. It is about the body.

[0002]

2. Description of the Related Art Conventionally, for example, in a developing device for developing an electrostatic latent image formed on the surface of a photosensitive drum as an image carrier with toner of a one-component developer, friction between toner particles, developer carrying Due to the friction between the developing sleeve as a body and the toner particles and the friction between the toner particles and the member that regulates the toner application amount on the developing sleeve, a positive or negative electric charge is given to the toner particles, and this toner is extremely transferred onto the developing sleeve. It is applied thinly and conveyed to the developing area where the photosensitive drum and developing sleeve face each other, and in the developing area, toner flies and adheres to the electrostatic latent image on the surface of the photosensitive drum to develop, and the electrostatic latent image is visualized as a toner image. It is known to be an image.

As the developer carrier used for the above-mentioned development, for example, a metal, its alloy or its compound is molded into a cylindrical shape and the surface thereof is subjected to electrolysis, blasting, sanding, etc. to have a predetermined surface roughness. What was processed like this is used. However, in this case, the toner existing in the vicinity of the surface of the developer carrying member in the toner layer formed on the surface of the developer carrying member by the regulating member has a very high electric charge, and the surface of the carrying member has a mirroring force. It will be strongly attracted. As a result, the opportunity for friction between the toner and the carrier is lost, and the toner cannot have a suitable charge.
Under such a condition, sufficient development and transfer are not performed, resulting in an image with many image density irregularities and scattered characters. In order to prevent the generation of toner having an excessive charge as described above and the strong adhesion of the toner, a coating in which a conductive substance such as carbon black or graphite or a solid lubricant is dispersed in a binder resin is used as the developer. A method of forming on a carrier is proposed in Japanese Patent Laid-Open No. 36570/1993. Furthermore, the film is a durability test of the developing device (long-term use)
In order to stabilize the toner carrying property of the developer carrier, that is, in order to stabilize the surface roughness of the developer carrier,
A method in which spherical particles are further included in the coating is proposed in JP-A-3-200986.

[0004]

However, in recent years, it has been desired to fix the toner at a low temperature from the viewpoint of further improving the durability of the developer carrying member and saving energy, and therefore, in such a model (developing apparatus), The above method is insufficient. For example, in the conventional LBP, it suffices that the developer carrier has a durable number of 10,000 sheets and the image quality is stable, but recently there are models that require stable image quality of 30,000 sheets or more. Further improvement in wear resistance of is required. In order to fix the toner at a low temperature, the glass transition temperature Tg is 60 ° C. or higher.
Since there are models that use a toner having a g of 60 ° C. or less, the toner is affected by the temperature rise of the main body and the like, and is easily fused on the developer carrying member. In such a model, in the latter half of the durability test, the surface roughness of the developer carrying member is maintained, but since the graphite is missing from the film and the added spherical particles are exposed on the surface, Conductivity, lubricity, and releasability are locally deteriorated on the surface of the carrier, and excessive charging of the toner and fusing of the toner to the surface of the carrier are likely to occur, which causes reduction in image density. . Therefore, the object of the present invention is to maintain the abrasion resistance of the coating even in the long-term durability test of the developing device more than before, to stabilize the surface roughness and the charge imparting property to the toner, and to prevent the toner from being excessively charged,
It is an object of the present invention to provide a developer carrying body in which fusion on the developer carrying body is suppressed and an image density is less likely to decrease. Another object of the present invention is to provide a developer carrier capable of eliminating sleeve ghost.

[0005]

According to the present invention, in the developer carrying member carrying the one-component developer for developing the latent image formed on the image carrying member, the surface of the developer carrying member is And a coating layer containing at least conductive spherical particles and spherical particles charged to the opposite polarity to the toner in the binder resin.

The developer carrying member of the present invention comprises a cylindrical substrate and a coating layer coating the surface of the substrate. The operation of the developer carrying member of the present invention will be described based on FIG. 1 which is an example of the present invention. The coating layer 1 includes spherical particles 2 that have been subjected to a conductive treatment, spherical particles 3 that are charged to the opposite polarity to the toner, and a binder resin 5.
And, if necessary, the conductive substance 4 and / or the solid lubricant 6
And is coated on the cylindrical substrate 7. In such a developer carrying member, even if the coating layer 1 is abraded by the long-term durability test, the electrically conductive spherical particles 2 are exposed and the conductivity of the coating layer 1 is maintained, so that the toner is prevented from being excessively charged. Also, fusion of the toner on the developer carrying member is prevented. Further, since the toner is favorably charged by the spherical particles 3 that are charged in the opposite polarity to the toner, a good image density can be obtained even under high temperature and high humidity. Further, since the spherical particles 2 that have been subjected to the conductive treatment and the spherical particles 3 that are charged to the opposite polarity to the toner have a spherical shape, the surface roughness of the coating layer 1 is maintained even during the durability test, and the toner is developed. The transportability to the parts is also kept constant. Therefore, the surface roughness of the coating is J
The IS center line average roughness (Ra) is preferably in the range of 0.2 to 3.5 μm. When Ra is less than 0.2 μm, the amount of charge on the developer carrying member is large and the developability is insufficient. When Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer on the developer carrying member, resulting in uneven density on the image.

Next, each material constituting the coating layer 1 will be described. Examples of the spherical particles 2 having conductivity are metal oxides such as zinc oxide, zinc sulfide, barium sulfate, titanium oxide, tin oxide, niobium oxide, manganese oxide, lead oxide, copper oxide, indium oxide, and iridium oxide, and these. Coated with a good conductive material,
Conductive treated by doping with substances with different oxidation numbers; Resin-based spherical particles such as phenol resin; Carbonized and / or graphitized by firing mesocarbon microbeads; Bulk mesophase pitch by the mechanochemical method (petroleum-based or coal-based pitch containing optically anisotropic liquid crystals called mesophase is roughly crushed by a crusher such as a jaw crusher, and finely pulverized by a dry or wet ball mill or the like. (Obtained by crushing), and heat-treated under a certain condition and then baked to carbonize the surface to make it conductive, and the like. These are used alone or in combination of two or more. The volume average particle diameter of the spherical particles 2 having conductivity used in the present invention is preferably in the range of 0.2 to 50 μm. If the thickness is less than 0.2 μm, it is difficult to obtain a suitable surface roughness of the developer bearing member, and the image quality is likely to deteriorate. If it exceeds 50 μm, it is not preferable because it protrudes from the coating film, and unauthorized development easily occurs only in that portion.

The spherical particles 3 charged to the opposite (reverse) polarity to the toner include (1) phenol resin, epoxy resin, melamine resin, silicone resin, methyl methacrylate resin (PMMA), for negatively charged toner. Examples thereof include spherical particles of a positively chargeable substance such as a terpolymer of methacrylate such as polystyrene / n-butyl methacrylate / silane terpolymer, a styrene-butadiene copolymer, polycaprolactone, and a nitrogen-containing polymer such as polyvinylpyridine or polyamide. For (2) positively charged toner, polyvinylidene fluoride, polyvinyl chloride,
Polytetrafluoroethylene, polytetrachlorofluoroethylene, polyperfluoroalkoxylated ethylene, polytetrafluoroalkoxyethylene, fluorinated ethylene propylene-polytetrafluoroethylene copolymer, trifluorochloroethylene-vinyl chloride copolymer, etc. Examples thereof include spherical particles of a negatively chargeable substance such as a halogenated polymer, polycarbonate and polyester. These spherical particles are used alone or in combination of two or more. The particle size of the spherical particles 3 charged in the opposite polarity to the toner used in the present invention is preferably 0.1 to 50 μm. If the thickness is less than 0.1 μm, it is difficult to obtain a suitable roughness on the surface of the developer bearing member, and the image quality tends to deteriorate. If it exceeds 50 μm, it is not preferable because it protrudes from the coating film, and unauthorized development easily occurs only in that portion.

As the conductive substance other than the above-mentioned conductive spherical particles, which is used for adjusting the resistance value of the coating as necessary, for example, metal powder of aluminum, copper, nickel, silver, etc., antimony oxide, indium oxide. , Metal oxides such as tin oxide, and carbon materials such as carbon fiber, carbon black, and graphite. Among them, carbon black, particularly conductive amorphous carbon, has particularly excellent electric conductivity, and it is possible to obtain a wide range of conductivity by filling the polymer material with conductivity and controlling the addition amount. It is preferably used for. The particle size of conductive amorphous carbon is 10 to 80 mμm
Are preferred. These are also used alone or in combination of two or more.

Further, in order to further reduce the adhesion of the toner to the developer carrying member, a solid lubricant may be mixed in the coating film if necessary. Examples of solid lubricants include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-selenniobium, calcium chloride-graphite, and talc. Among them, graphite is preferably used because it has conductivity as well as lubricity and has the function of reducing the amount of toner having an excessively high charge and having a charge amount suitable for development.

As the binder resin for dispersing the conductive spherical particles and the spherical particles charged with the opposite polarity to the toner to form the coating layer, a phenol resin, an epoxy resin, a polyamide resin, a polyester resin, a polycarbonate is used. Resin, polyolefin resin, silicone resin,
Known resins such as fluorine-based resins, styrene-based resins and acrylic resins are used. A thermosetting or photocurable resin is particularly preferable.

A coating material for forming a film is prepared by using each of the components described above, and the coating material is applied to the surface of the developer carrying base to a predetermined dry thickness and dried.
A developer carrier having a coating layer is obtained. The coating is usually made of a binder such as conductive spherical particles dispersed in a binder resin.
3 to 200 parts by weight of conductive spherical particles per 3 parts by weight, 3 to 200 parts by weight of spherical particles charged to the opposite polarity to the toner, 0 to 200 parts by weight of a conductive substance other than the above, and / or 0 to 200 parts by weight of solid lubricant. It is used in the range of parts and is manufactured by uniformly mixing and dispersing these in a binder solution. The method for producing the paint may be according to a conventional method and is not particularly limited. A coating layer is formed by applying the coating material for coating a film onto the surface of the developer substrate by a usual coating method such as spraying and drying. The thickness of the coating layer is usually in the range of 2 to 200 μm.

Next, a developing device in which the developer carrier of the present invention is incorporated will be described with reference to FIGS. In FIG. 2, an image carrier that carries an electrostatic latent image formed by a known process, for example, the electrophotographic photosensitive drum 8 is rotated in the direction of arrow B. The developing sleeve 15 as a developer carrying member carries the magnetic toner 11 as a one-component magnetic developer supplied from the hopper 10 and rotates in the direction of arrow A to develop the developing sleeve 1
The toner 11 is conveyed to the developing portion D where the photosensitive drum 8 and the photosensitive drum 8 face each other. Inside the developing sleeve 15, a magnet 12 is arranged to magnetically attract and hold the magnetic toner 11 on the developing sleeve 15. Toner 11 is developing sleeve 1
By friction with 5, the triboelectric charge that makes it possible to develop the electrostatic latent image on the photosensitive drum 8 is obtained.

In order to regulate the layer thickness of the magnetic toner 11 conveyed to the developing section D, a regulating blade 9 made of a ferromagnetic metal is provided from the surface of the developing sleeve 15 to have a thickness of about 200 to 300 μm.
It is suspended from the hopper 10 so as to face the developing sleeve 15 with a gap width of m. By the magnetic force lines from the magnetic pole N1 of the magnet 12 being concentrated on the blade 9,
A thin layer of magnetic toner 11 is formed on the developing sleeve 15. A non-magnetic blade can also be used as the blade 9.

The thin layer of the magnetic toner 11 formed on the developing sleeve 15 is preferably thinner than the minimum gap between the developing sleeve 15 and the photosensitive drum 8 in the developing section D. The present invention is particularly effective for a developing device of the type that develops an electrostatic latent image with such a toner thin layer, that is, a non-contact type developing device. However, in the developing section, the thickness of the toner layer is different from that of the developing sleeve 15 and the photosensitive drum 8.
The present invention can also be applied to a developing device having a thickness equal to or larger than the minimum gap between and, that is, a contact type developing device. In order to avoid complexity of the description, a non-contact type developing device will be described below as an example.

A developing bias voltage is applied to the developing sleeve 15 by a power source 16 in order to fly the magnetic toner 11 which is the one-component magnetic developer carried on the developing sleeve 15. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the image portion (the area where the toner 11 is attached and visualized) of the electrostatic latent image and the potential of the background portion is the developing sleeve 15. Is preferably applied to. on the other hand,
In order to increase the density of the developed image or improve the gradation, an alternating bias voltage is applied to the developing sleeve 15,
An oscillating electric field whose direction is alternately inverted may be formed in the developing portion D. In this case, it is preferable to apply to the developing sleeve 15 an alternating bias voltage in which a DC voltage component having a value between the potential of the image portion and the potential of the background portion is superimposed.

Further, in so-called regular development in which toner is visualized by adhering toner to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion, toner charged to a polarity opposite to the polarity of the electrostatic latent image is used. On the other hand, in so-called reversal development in which toner is made visible by adhering toner to the low potential portion of the electrostatic latent image, the toner uses toner that is charged to the same polarity as the electrostatic latent image. In addition, high potential,
The low potential is expressed by an absolute value. In any case, the toner 11 is charged to the polarity for developing the electrostatic latent image by friction with the developing sleeve 15. Toner 11
The silica externally added to is also charged by friction with the developing sleeve 15.

FIG. 3 is a block diagram showing another example of the developing device of the present invention, and FIG. 4 is a block diagram showing still another example of the present invention. In the developing device of FIGS. 3 and 4, as a member for regulating the layer thickness of the magnetic toner 11 on the developing sleeve 15,
An elastic plate 18 made of a material having rubber elasticity such as urethane rubber or silicone rubber or a metal elastic material such as phosphor bronze or stainless steel is used.
In the developing device of FIG. 4, the developing sleeve 15 is pressed against the developing sleeve 15 in a posture opposite to the rotation direction.
The feature is that they are pressed into contact with each other in the same direction as the rotation direction. In such a developing device, a thinner toner layer can be formed on the developing sleeve 15.

The other constructions of the developing device shown in FIGS. 3 and 4 are basically the same as those of the developing device shown in FIG.
2, the same reference numerals as those shown in FIG. 2 indicate the same members. The developing device for forming the toner layer on the developing sleeve 15 as described above, as shown in FIGS. 3 and 4, uses a one-component magnetic developer containing a magnetic toner as a main component and a non-magnetic toner. It is also suitable for those using a one-component non-magnetic developer containing as a main component. In either case, the toner is rubbed against the developing sleeve 15 by the elastic plate 18, so that the triboelectric charge amount of the toner is increased and the image density is improved.

[0020]

The present invention will be described in detail below with reference to examples. Unless otherwise specified, parts and% in the following examples and comparative examples are based on weight. The average particle diameter is a volume average particle diameter.

Example 1 Phenolic resin 200 parts Graphite 20 parts Isopropyl alcohol (IPA) 220 parts The above material was sand milled with zirconia particles having a diameter of 2 mm for 10 hours, and then the zirconia particles were separated by sieving to obtain a solid content of 50%. Dispersion of binder resin (binder) containing solid lubricant (stock solution 1) (graphite / binder =
0.2 / 2) was obtained. Stock solution 1 220 parts (Sb-doped) SnO ₂ coated TiO ₂ spherical particles (average particle size 0.2 μm) 35 parts PMMA spherical particles (average particle size 50 μm) 5 parts Sand mill for 1 hour with the above materials using glass beads having a diameter of 3 mm Then, the glass beads are separated by sieving and IP
Paint 1 (0.2-conductively treated TiO ₂ spherical particles / 50-PMMA spherical particles: L (solid lubricant) / C (conductive substance) / RC (conductive spherical particles) whose solid content was adjusted to 30% with A ) / B (binder resin) / RT (spherical particles charged to the opposite polarity to the toner) = 0.2 / 0 / 0.7 / 2/0.
1) was obtained (the numerical value before the spherical particles represents the average particle diameter μm. The same applies to the following examples).

This coating material was applied by spraying to an Al cylinder having a diameter of 16 mm so as to form a film having a dry thickness of 10 μm, and then heated and cured at 150 ° C./30 minutes by a hot air dryer to carry a developer carrier. Was produced. When the surface roughness of this coating was measured, it was Ra = 2.0 μm. Further, the same coating material as the coating material 1 was obtained except that PMMA spherical particles of the coating material 1 having the average particle diameter of 60 μm were used, and this was used to prepare a developer carrying member (Ra = 2.0 μm).
These developer carrying bodies (sleeve) are incorporated into Laser Jet Si (HP manufactured by LBP) at 10 ° C and 10%.
Image formation was performed in two environments of low temperature and low humidity (L / L) of RH and high temperature and high humidity (H / H) of 30 ° C. and 80% RH.

As a developer, 1.2 weight percent of colloidal silica is added to the toner having a weight average particle diameter of 6 μm prepared by the following formulation.
% Externally added one was used. Styrene-butyl acrylate-maleic acid-n-butyl half ester copolymer (Tg56 ° C) 100 parts Magnetite 100 parts Negative charge control agent 3 parts Low molecular weight polypropylene 5 parts The particle size of the conductive spherical particles is Coulter LS- 130
It was measured with a laser diffraction type particle size distribution meter (manufactured by Coulter). On the other hand, the average particle size of the spherical particles charged to the opposite polarity to the toner was measured with a Coulter Multisizer (manufactured by Coulter Co.) using a 100 μm aperture. The same applies to the following examples.

The image characteristics and various characteristics of the sleeve were evaluated by the following methods and standards. This is the same in the following examples. [Image Characteristics] The image densities after the images of 10 sheets, 20,000 sheets and 40,000 sheets were printed were visually evaluated with a Macbeth reflection densitometer, and the evaluation results were shown by the following indexes. (1) Image density (Macbeth reflection density) ◎: 1.4 or more ○: 1.2 or more and less than 1.4 △: 1.0 or more and less than 1.2 ×: less than 1.0 (2) Ghost (visual) ◎ : Excellent ◯: Good Δ: Practical x: Not practical [Coating strength] (1) Roughness change (represented by ΔRa) Surface roughness of the coated developer carrier at the initial stage and after printing 40,000 sheets. Ra is a surf coder SE-3 made by Kosaka Laboratory
At 300, 3 points in the axial direction × 2 points in the circumferential direction = 6 points were measured, and the average value was taken. (2) Abrasion (represented by Δ film thickness) The outer diameter of the coated developer carrier was measured with a laser stereometer at the initial stage and after printing 40,000 sheets. It was calculated. The above results are shown in Table 1. still,
The upper part of the table shows the results when the average particle size of the PMMA spherical particles is 50 μm, and the lower part shows the results when the average particle size is 60 μm. Both were good results.

Example 2 Phenolic resin 100 parts (Sb-doped) SnO ₂ coated TiO ₂ spherical particles (average particle size 0.2 μm) 45 parts Nylon spherical particles (average particle size 50 μm) 5 parts IPA 150 parts The above materials had a diameter of 3 mm Sand-mill with glass beads for 1 hour, then separate the glass beads by sieving
Paint 2 whose solid content was adjusted to 30% with A (0.2-conductive-treated TiO ₂ spherical particles / 50-nylon spherical particles: L / C
/RC/B/RT=0/0/0.9/2/0.1) was obtained, and a developer carrier (Ra = 1.9) was obtained in the same manner as in Example 1.
μm) was prepared. Further, the same coating material as the coating material 1 was obtained except that the TiO ₂ spherical particles which had been subjected to the conductive treatment were replaced with the particles having an average particle diameter of 0.1 μm, and the developer carrying member (Ra = 1.
8 μm) was prepared. These developer carrying members are used in Example 1
The evaluation was performed in the same manner as above, and the results shown in Table 1 were obtained. In the upper row of the table, the average particle size of the electrically conductive TiO ₂ spherical particles is 0.2 μm.
In the case of, the lower row is the result in the case of 0.1 μm. Both were good results.

Example 3 Undiluted solution 1 (of Example 1) 220 parts (Sb-doped) SnO ₂ coated Ti—Ni—Sb oxide spherical particles (average particle size 0.4 μm) 25 parts PMMA spherical particles (average particle size 15 μm) ) 15 parts Coating material 3 (0.2-T)
i-Ni-Sb oxide spherical particles / 15-PMMA spherical particles: L / C / RC / B / RT = 0.2 / 0 / 0.5 / 2
/0.3) was obtained, and using this, a developer carrier (Ra = 1.8 μm) was produced in the same manner as in Example 1. This developer carrying member was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results
Shown in Good results were obtained after 10 images, 20,000 images, and 40,000 images.

Example 4 Phenolic resin 100 parts (Sb-doped) SnO ₂ coated Ti—Ni—Sb oxide spherical particles (average particle size 0.4 μm) 35 parts Nylon spherical particles (average particle size 15 μm) 15 parts IPA 150 parts A coating material 4 (0.4
-Ti-Ni-Sb oxide spherical particles-15-nylon spherical particles: L / C / RC / B / RT = 0/0 / 0.7 / 2
/0.3) was obtained, a developer carrying member (Ra = 1.7 μm) was prepared in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. After 10 images, 2
Good results were obtained after 10,000 sheets and 40,000 sheets.

Example 5 Phenolic resin 200 parts Graphite 30 parts IPA 230 parts The above material was sand milled with zirconia particles having a diameter of 2 mm for 10 hours, and then the zirconia particles were separated by sieving to contain a solid lubricant having a solid content of 50%. Binder resin dispersion (stock solution 2) (graphite / binder = 0.3 / 2)
Got Using this, the following formulation was used in the same manner as in Example 1 to prepare coating 5 (5-spherical carbon particles / 0.1-PMMA spherical particles: L / C / RC / B / RT = 0.3 / 0 / 0.4 / 2
/0.3) was obtained. Stock solution 2 230 parts Spherical carbon particles (average particle size 5 μm) 20 parts PMMA spherical particles (average particle size 0.1 μm) 15 parts In the same manner as in Example 1, a developer carrying member (Ra = 1. 7 μm) was prepared and imaged and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. Good results were obtained after 10 images, 20,000 images, and 40,000 images.

Example 6 Phenolic resin 100 parts Spherical carbon particles (average particle size 5 μm) 25 parts Nylon spherical particles (average particle size 0.1 μm) 25 parts IPA 150 parts Coating material prepared in the same manner as in Example 1 using the above materials 6 (5-spherical carbon particles / 0.1 nylon spherical particles: L / C / RC /
B / RT = 0/0 / 0.5 / 2 / 0.5), and a developer carrier (Ra = 1.9 μm) was prepared in the same manner as in Example 1.
Images were drawn out and evaluated in the same manner as in Example 1. Table 1 shows the evaluation results
Shown in Good results were obtained after 10 images, 20,000 images, and 40,000 images.

Example 7 Phenolic resin 200 parts Graphite 30 parts Carbon black 20 parts IPA 250 parts Using the above materials and following the same procedure as in Example 1, the solid content is 50%.
Dispersion liquid of binder resin containing solid lubricant (stock solution 3) (graphite / carbon black / binder = 0.3 / 0.
2/2) was obtained. Using this, the following formulation was followed by the same production method as in Example 1 to obtain paint 7 (50-spherical carbon particles / 0.1-P).
MMA spherical particles: L / C / RC / B / RT = 0.3 /
0.2 / 0.1 / 2 / 0.4) was obtained. Undiluted solution 3 250 parts Spherical carbon particles (average particle size 50 μm) 5 parts PMMA spherical particles (average particle size 0.1 μm) 20 parts Using the paint 7, the developer carrier (Ra =
1.7 μm) was prepared. Further, a coating material was prepared by replacing the PMMA spherical particles of the coating material 7 with the particles having an average particle diameter of 0.05 μm, and using this, a developer carrying member (Ra = 1.6 μm) was prepared.
m) was prepared. These developer carrying members were imaged and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. still,
In the upper part of the table, the average particle diameter of PMMA spherical particles is 0.1 μm.
In the case of, the lower row is the result in the case of 0.05 μm. Both were good results.

Example 8 Phenolic resin 200 parts Carbon black 50 parts IPA 250 parts The above material was sand milled with zirconia particles having a diameter of 2 mm for 10 hours, and then the zirconia particles were separated by sieving to obtain a conductive binder having a solid content of 50%. Resin dispersion (stock solution 4)
(Carbon black / binder = 0.5 / 2) was obtained. Using this, with the following formulation and the same production method as in Example 1, paint 8 (50-spherical carbon particles / 0.1-nylon spherical particles: L / C / RC / B / RT = 0 / 0.5 / 0 .1 / 2
/0.4) was obtained. Undiluted solution 4 250 parts Spherical carbon particles (average particle size 50 μm) 5 parts Nylon spherical particles (average particle size 0.1 μm) 20 parts Using the paint 8, the developer carrier (Ra =
1.9 μm) was produced. Further, a coating material was obtained in which the spherical carbon particles of the coating material 8 were replaced with the particles having an average particle diameter of 60 μm, and this coating material was applied to prepare a developer carrying member (Ra = 2.0 μm). These developer carrying members were imaged and evaluated in the same manner as in Example 1. Table 1 shows the evaluation results. The upper row in the table is the result when the average particle diameter of the spherical carbon particles is 50 μm, and the lower row is the result when the average particle diameter is 60 μm. Both were good results.

Comparative Example 1 Phenolic resin 200 parts Graphite 80 parts Carbon black 20 parts IPA 300 parts The above material was sand milled with zirconia particles having a diameter of 2 mm for 10 hours, and then the zirconia particles were separated by sieving to obtain a solid content of 50%. Dispersion of conductive binder resin (stock solution 5)
(Graphite / carbon black / binder = 0.
8 / 0.2 / 2) was obtained. The solid content of this is 30 with IPA
%, And in the same manner as in Example 1, the developer carrying member (Ra
= 1.0 μm) was manufactured. This developer carrying member was evaluated in the same manner as in Example 1. The results are shown in Table 1. The image density was low from the beginning, and the decrease in Ra was also remarkable. After 20,000 sheets, toner fusion occurred.

Comparative Example 2 Undiluted solution 5 (of Comparative Example 1) 300 parts Phenol spherical particles (average particle size 20 μm) 5 parts The same materials as in Example 1 were used to prepare coating material N (20-phenol spherical particles: L / C / RC / B / R (spherical particles) =
0.8 / 0.2 / 0/2 / 0.1) was obtained, and this developer was used in the same manner as in Example 1 to carry a developer (Ra = 1.9 μm).
m) was prepared. This was evaluated in the same manner as in Example 1. The results are shown in Table 1. After 10 sheets and 20,000 sheets were printed, there was no problem, but after 40,000 sheets, ghost deterioration due to excessive charging of toner, reduction in image density due to toner fusion, reduction in surface roughness and abrasion of coating film were large.

Table 1

Example 9 In Example 1, the PMMA spherical particles had an average particle size of 50 μm.
Example 1 except that polyester spherical particles of m
Paint 9 (0.2-conductive treatment Ti
O ₂ spherical particles / 50-polyester spherical particles: L / C /
RC / B / RT = 0.2 / 0 / 0.7 / 2 / 0.1), and carrying a developer in the same manner as in Example 1 except that this coating material was applied to an aluminum sleeve having a diameter of 20 mm. Body (Ra
= 2.0 μm) was produced. Further, a developer carrying member (Ra = 2.0 μm) was prepared in the same manner as above except that the above polyester spherical particles were replaced with the particles having an average particle diameter of 60 μm. These developer carrier (sleeve) is NP6
030 (Canon Copier) toner regulating member is modified into an elastic body and installed at 10 ° C., 10% RH low temperature and low humidity (L / L) and 30 ° C., 80% RH high temperature and high humidity (H / Images were displayed in the two environments of H).

As the developer, a toner having a weight average particle size of 6 μm prepared by the following formulation and 1.2% of colloidal silica treated with amino-modified silicone oil was externally added. Styrene-acrylic resin (Tg 56 ° C.) 100 parts Magnetite 100 parts Positive charge control agent 3 parts Low molecular weight polypropylene 5 parts By the same evaluation method as in Example 1, 10 images, 30,000 images and 50,000 images were printed. The latter was evaluated and the results shown in Table 2 were obtained. In the upper row of the table, the particle size of spherical polyester particles is 5
In the case of 0 μm, the lower row shows the result in the case of 60 μm.
Both were good results.

Example 10 Nylon spherical particles in Example 2 had an average particle size of 50 μm.
Coating material 10 (0.2-conductively treated TiO _{2) was} prepared by the same formulation and manufacturing method as in Example 1, except that the spherical particles of Teflon were used instead.
Spherical particles / 50-Teflon spherical particles: L / C / RC / B
/RT=0/0/0.9/2/0.1) was obtained and was coated on an aluminum sleeve having a diameter of 20 mm in the same manner as in Example 1 to carry a developer (Ra = 1. 9 μm) was prepared. Further, a developer carrying member (Ra = 1.8 μm) was prepared in the same manner as described above except that the conductively treated TiO ₂ spherical particles of the coating material 10 were replaced with the particles having an average particle diameter of 0.1 μm. Image formation and evaluation of these developer carrying members were carried out in the same manner as in Example 9, and the results shown in Table 2 were obtained. The upper row in the table shows the result when the particle diameter of the electrically treated TiO ₂ spherical particles was 0.2 μm, and the lower row shows the result when the particle diameter was 0.1 μm. Both were good results.

Example 11 The PMMA spherical particles in Example 3 had an average particle size of 15 μm.
Paint 11 (0.4-conductivity treated Ti) was prepared in the same manner as in Example 3 except that the polyester spherical particles of
-Ni-Sb oxide spherical particles-15-Polyester spherical particles: L / C / RC / B / RT = 0.2 / 0 / 0.5 /
2 / 0.3) was obtained, and a developer carrying member (Ra = 1.8 μm) was produced in the same manner as in Example 1 except that this was coated on an aluminum sleeve having a diameter of 20 mm. This is Example 9
The image was drawn out and evaluated in the same manner as. Table 2 shows the results. Good results were obtained after 10 images, 30,000 images, and 50,000 images.

Example 12 Nylon spherical particles in Example 4 had an average particle size of 15 μm.
Paint 12 (0.4-conductive treated Ti-N) was prepared by the same formulation and manufacturing method as in Example 4 except that the spherical particles of Teflon were used.
i-Sb oxide spherical particle / 15-Teflon spherical particle: L
/C/RC/B/RT=0/0/0.7/2/0.3)
Was obtained, and the developer carrying member (Ra = Ra =
1.7 μm) was prepared. This was imaged in the same manner as in Example 9 and evaluated. The results are shown in Table 2. After 10 images, 3
Good results were obtained after 10,000 sheets and 50,000 sheets.

Example 13 In Example 5, the PMMA spherical particles had an average particle size of 0.1 μm.
Example 3 except that polyester spherical particles of m were used instead.
Paint 13 (5-spherical carbon particles.
0.1-polyester spherical particles: L / C / RC / B / R
T = 0.3 / 0 / 0.4 / 2 / 0.3) was obtained and was coated on an aluminum sleeve having a diameter of 20 mm in the same manner as in Example 1 to carry a developer (Ra = 1). 0.7 μm) was prepared. This was evaluated in the same manner as in Example 9. Table 2 shows the results. The good results were obtained after 10 sheets, 30,000 sheets, and 50,000 sheets.

Example 14 Nylon spherical particles in Example 6 had an average particle size of 0.1 μm.
Paint 14 (5-spherical carbon particles.0.1-) was prepared in the same manner as in Example 6 except that m Teflon spherical particles were used instead.
Nylon spherical particles: L / C / RC / B / RT = 0/0 /
0.5 / 2 / 0.5) and similarly the developer carrying member (Ra
= 1.9 μm) was produced. This was imaged in the same manner as in Example 9, and the evaluation results are shown in Table 2. The good results were obtained after 10 sheets, 30,000 sheets, and 50,000 sheets.

Example 15 In Example 7, the PMMA spherical particles had an average particle size of 0.1 μm.
Example 7 except that polyester spherical particles of m were used instead.
Paint 15 (50-spherical carbon particles / 0.1 polyester spherical particles: L / C / RC / B / R)
T = 0.3 / 0.2 / 0.1 / 2 / 0.4) was obtained and was coated on an aluminum sleeve having a diameter of 20 mm in the same manner as in Example 1 to carry a developer carrier (Ra). = 1.7μ
m) was prepared. Further, a developer carrying member (Ra = 1.6 μm) was prepared in the same manner as described above, except that the polyester spherical particles had an average particle diameter of 0.05 μm. These developer carrying members were imaged and evaluated in the same manner as in Example 9. Table 2 shows the results. The upper row in the table shows the results when the particle diameter of the polyester spherical particles is 0.1 μm, and the lower row shows the results when the particle diameter is 0.05 μm. Both were good results.

Example 16 The nylon spherical particles in Example 8 had an average particle size of 0.1 μm.
Coating material 16 (50-spherical carbon particles.
0.1-Teflon spherical particles: L / C / RC / B / RT =
0 / 0.5 / 0.1 / 2 / 0.4), which has a diameter of 2
Example 1 except that it was applied to a 0 mm aluminum sleeve.
A developer bearing member (Ra = 1.9 μm) was prepared in the same manner as in (1). Further, the spherical carbon particles of the paint 16 have an average particle size of 60
The developer carrying member (Ra
= 2.0 μm) was produced. With these sleeves,
Images were drawn out and evaluated in the same manner as in Example 9. The results are shown in Table 2. The upper row in the table is the result when the particle diameter of the spherical carbon particles is 50 μm, and the lower row is the result when the particle diameter is 60 μm. Both were good results.

Comparative Example 3 Dispersion of conductive binder resin (stock solution 6) was carried out in the same manner as in Comparative Example 1 except that the phenol resin was replaced by the polycarbonate resin and the phenol spherical particles were replaced by the polycarbonate spherical particles. Got The solid content was adjusted to 30% with IPA, and a developer carrying member (Ra = 1.0 μm) was prepared in the same manner as in Example 9. The evaluation results are shown in Table 2. The image density was low from the beginning, and the decrease in Ra was also remarkable. Toner fusion occurred after 30,000 sheets.

Comparative Example 4 Paint P [20-Polycarbonate spherical particles: L / C / R / was used in the same manner as in Comparative Example 2 except that the spherical phenol particles were replaced by the spherical polycarbonate particles.
C / B / R (spherical particles = 0.8 / 0.2 / 0/2/0.
1)] was obtained, and in the same manner as in Example 9, a developer carrying member (Ra
= 1.9 μm) was produced. The evaluation results are shown in Table 2. 1
After 0 sheets and 30,000 sheets, there was no problem, but after 50,000 sheets, ghost deterioration due to excessive charging of toner, image density reduction due to toner fusion, surface roughness reduction and abrasion of the coating were large.

Table 2

[0047]

As described above, according to the present invention, the abrasion resistance of the surface film of the developer carrier is remarkably improved even in the long-term durability test of the developing device such as electrophotography and electrostatic recording. Further, the surface roughness and the property of imparting charge to the toner are stabilized, and effects such as excessive charging of the toner and fusion of the toner onto the developer carrying member are suppressed. As a result, it is possible to stably obtain a high-quality image for a long period of time in which the image density does not decrease and the sleeve ghost does not occur even at low temperature and low humidity and high temperature and high humidity.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of a part of a developer carrier of the present invention.

FIG. 2 shows an example of a developing device in which the developer carrier of the present invention is incorporated.

FIG. 3 shows another example of a developing device in which the developer carrier of the present invention is incorporated.

FIG. 4 shows another example of a developing device in which the developer carrier of the present invention is incorporated.

[Explanation of symbols]

 1: Coating layer 2: Conductive-treated spherical particles 3: Spherical particles charged with the opposite polarity to the toner 4: Conductive substance 5: Binder resin 6: Solid lubricant 7: Cylindrical substrate 8: Photosensitive drum 9: Regulation blade 10: Hopper 11: Toner 12: Magnet 13: Cylindrical substrate 14: Coating layer 15: Developing sleeve 16: Power supply 17: Stirrer 18: Elastic plate A: Rotating direction of developing sleeve B: Rotating direction of photosensitive drum D : Development section

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yasuhide Goseki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A developer carrying member carrying a one-component developer for developing a latent image formed on an image carrying member, wherein the surface of the developer carrying member contains at least conductive spherical particles in a binder resin. A developer carrying member, which is provided with a coating layer containing spherical particles charged to the opposite polarity to the toner. 2. The developer carrying member according to claim 1, wherein the binder resin further contains a conductive substance other than the conductive spherical particles and / or a solid lubricant. 3. The volume average particle diameter of the conductive spherical particles is 0.2.
The developer carrying member according to claim 1 or 2, wherein the developer carrying member has a thickness of about 50 m. 4. The developer carrying member according to claim 1, wherein the spherical particles charged in the opposite polarity to the toner have a volume average particle diameter of 0.1 to 50 μm.