JP3363726B2 - Developer carrier and process cartridge - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic method, in which an electrostatic latent image formed on an electrostatic latent image holding member such as an electrophotographic photosensitive member or an electrostatic recording dielectric is developed and visualized. a developer carrying member to be used for, and a pulp b Seth cartridge developer carrying member is not used.

[0002]

2. Description of the Related Art Conventionally, for example, as a developing device for visualizing an electrostatic latent image formed on a surface of a photosensitive drum as an electrostatic latent image holder with a magnetic toner as a one-component developer, for example, FIG. A device as shown in is known. In FIG. 6, a developer container 53 holds a magnetic toner 54 as a one-component developer, which causes friction between particles of the magnetic toner and a developing sleeve 58 as a developer carrier and magnetic toner particles. Due to the friction between them, the electrostatic latent image charge formed on the photosensitive drum 51 and the charge having a polarity opposite to that of the developing reference potential are applied to the magnetic toner particles, and the magnetic blade 52 moves the magnetic toner onto the developing sleeve 58 extremely. It is thinly applied and carried and conveyed to the developing area D formed by the photosensitive drum 51 and the developing sleeve 58, and is carried in the developing area D by the action of the magnetic field of the magnet 55 fixed in the developing sleeve 58. It is known that the magnetic toner that is ejected is made to fly to visualize the electrostatic latent image on the photosensitive drum 51. In addition, A and B indicate the respective rotating directions of the developing sleeve 58 and the photosensitive drum 51, 59 indicates a developing bias means for applying a developing bias voltage at the time of development, and 60 indicates a magnetic toner in the developer container 53. 54 is a stirring blade for stirring 54.

However, when such a one-component type developer is used, it is difficult to adjust the toner charge, and although various devises have been made by the developer, the toner charge becomes uneven and the charge durability is stable. The issues involved have not been completely resolved.

Particularly, while the developing sleeve is repeatedly rotated, the charge amount of the toner coated on the developing sleeve becomes too high due to the contact with the developing sleeve, and the toner is reflected by the surface of the developing sleeve. The so-called charge-up phenomenon, in which the toner is attracted to the surface of the developing sleeve and becomes immobile and does not move from the developing sleeve to the latent image on the electrostatic latent image holder (drum), is apt to occur particularly under low humidity. When such a charge-up phenomenon occurs,
Since the toner in the upper layer is less likely to be charged and the developing amount of the toner is reduced, problems such as thin line images and low image density of solid images occur.

Furthermore, since the toner layer forming state of the image portion (toner consuming portion) and the non-image portion are different and the charging state is different, for example, the position where a solid image having a high image density is once developed is developed. When the halftone image is developed at the developing position when the sleeve is rotated next time, a so-called sleeve ghost phenomenon that a trace of a solid image appears on the image is apt to occur.

Recently, in order to further improve the image quality of electrophotography, the particle size and the particle size of the toner have been reduced. For example, in order to improve resolution and sharpness and faithfully reproduce a latent image, it is common to use a toner having a weight average particle size of about 6 to 9 μm. Further, the fixing temperature of the toner tends to be lowered for the purpose of shortening the first copy time and saving power. In such a situation, the toner is more likely to electrostatically adhere to the developing sleeve, and the external physical force is apt to cause contamination of the developing sleeve surface or toner fusion. ing.

As a method for solving such a phenomenon, a developing sleeve in which a coating layer in which a conductive lubricant such as a solid lubricant and carbon is dispersed in a resin is provided on a metal substrate is used in a developing device. A method has been proposed. It is recognized that by using this method, the above-mentioned phenomenon is significantly reduced. However, in this method, the surface of the developing sleeve becomes uneven in shape, so that uniform charging is still insufficient, and there is a problem in durability such as brittleness of the coating layer.

In Japanese Patent Laid-Open No. 3-200986, a developing sleeve is proposed in which a conductive lubricant such as solid lubricant and carbon, and spherical particles are dispersed in a resin to provide a conductive coating layer on a metal substrate. Has been done. In this developing sleeve, the surface shape of the developing sleeve is made uniform, and the charging is made uniform and the abrasion resistance is improved. However, even in this developing sleeve, further improvement of durability performance such as improvement of abrasion resistance of the conductive coating layer and suppression of toner contamination and toner fusion when abrasion occurs is desired.

[0009]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to prevent repeated deterioration of the conductive coating layer on the surface of the developer carrier due to repeated copying or durability, to provide high durability and stable image quality. the resulting developer carrying member, and to provide a pulp b Seth cartridge having a developer carrying member.

The object of the present invention is to develop a high-quality image stably without causing problems such as density reduction, sleeve ghost and fog over a long period of time under different environmental conditions. carrier, and to provide a pulp b Seth cartridge having a developer carrying member.

The object of the present invention is to suppress the uneven charging of the toner on the surface of the developer carrier, which appears when a toner having a small particle diameter is used, and to develop the toner capable of giving an appropriate charge amount to the toner. carrier, and to provide a pulp <br/> b Seth cartridge having a developer carrying member.

[0012]

The above-mentioned objects can be achieved by the present invention described below.

[0013] Namely, the present invention provides a developer carrying member having a coating layer which covers at least the substrate and the substrate surface, the coating layer may be spherical particles dispersed contained in a binder resin and a binder resin At least (A) and fibrous particles (B) , and the volume resistance of the coating layer is 10 ³ Ω · cm or less.
Below, the center line average roughness of the coating layer surface is 0.4
To 3.5 μm, and the long diameter / short diameter of the spherical particles (A)
Ratio is 1.0 to 1.5, the number of the spherical particles (A)
Average particle diameter AL and average fiber diameter BL of the fibrous particles (B)
Satisfies 0.02 ≦ BL / AL ≦ 0.35 .

[0014]

[0015]

Furthermore, the present invention provides a process cartridge detachable from the main body of an image forming apparatus, wherein the process cartridge comprises: (i) an electrostatic latent image holding member for holding an electrostatic latent image; and (ii) the electrostatic latent image holding member. At least one developing means for developing the electrostatic latent image with the developer in the developing area is integrally provided, and the developing means contains a developer container for containing the developer, and the developer container accommodated in the developer container. A developing agent carrier for forming and carrying a thin layer of the developing agent on the surface and for transporting the developing agent to the developing area. in the developer carrying member having a coating layer coating the substrate surface, the coating layer may be spherical particles (a) and fibrous particles dispersed contained in a binder resin and the binder resin (B) at least Yes And the coating
The volume resistance of the layer is 10 ³ Ω · cm or less, and the coating layer
The center line average roughness of the surface is 0.4 to 3.5 μm.
And the ratio of major axis / minor axis of the spherical particles (A) is 1.0 to
And the number average particle size AL of the spherical particles (A) is 1.5.
The average fiber diameter BL of the fibrous particles (B) is 0.02 ≦ B
The present invention relates to a process cartridge characterized by satisfying L / AL ≦ 0.35 .

As a result of intensive studies on the above problems, the present inventors have made the fibrous particles (B) coexist in addition to the spherical particles (A) which give unevenness to the coating layer on the surface of the developer carrier. By forming a coating layer that is dispersed and contained in the binder resin, the fibrous particles are formed by the shape factor of the spherical particles and partially cover the irregularities to prevent scraping of the convexes and toner contamination. At the same time, the presence of the fibrous particles between the binder resin and the spherical particles makes it difficult to remove the spherical particles from the coating layer, and further the fine unevenness due to the fibrous particles is formed on the large unevenness of the coating layer surface. It was found that the effect of making toner contamination less likely to occur by doing so is the present invention.

Since the developer carrier has such a surface shape and structure, the characteristics of the coating layer can be maintained longer than in the conventional case, and a high quality image can be obtained for a long time.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments.

First, the spherical particles used in the coating layer coated on the surface of the substrate constituting the developer carrying member of the present invention will be described.

The number average particle size AL of the spherical particles (A) used in the present invention is 1 to 30 μm, preferably 2 to 20 μm.
Have.

Such spherical particles maintain a uniform surface roughness on the surface of the coating layer constituting the developer carrying member of the present invention, and at the same time, the surface of the coating layer is less likely to be worn, and even when it is worn, the coating layer is Is added in order to prevent the toner contamination and the toner fusion from occurring with little change in the surface roughness.

The number average particle size AL of the spherical particles (A) is 1 μm.
If it is less than m, there is no effect of imparting a uniform roughness to the surface of the developer carrier, and toner charge-up due to abrasion of the coating layer, toner contamination and toner fusion occur, resulting in deterioration of ghost image and image density. It is not preferable because it causes a decrease. On the other hand, when the number average particle size AL exceeds 30 μm, the surface roughness of the coating layer becomes too large, which makes it difficult to sufficiently charge the toner and reduces the mechanical strength of the coating layer. Not preferable.

In the present invention, the spherical particles in the spherical particles (A) mean particles having a ratio of major axis / minor axis of about 1.0 to 1.5, preferably a major axis / minor axis ratio of 1. 0 to
It is preferable to use 1.2 particles, particularly preferably spherical particles.

When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the dispersibility of the spherical particles in the coating layer deteriorates and the surface roughness of the coating layer becomes non-uniform, resulting in uniform toner particles. It is not preferable because it imparts sufficient charge and the strength of the coating layer becomes insufficient.

Various materials can be used as the composition of the spherical particles (A) added to the coating layer. For example, PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, or Resin particles of these copolymers, benzoguanamine resin, phenol resin, polyamide resin, nylon, fluorine resin, silicone resin, epoxy resin, polyester resin; metal oxide particles such as alumina and zinc oxide; carbon particles, conductive Conductive particles such as treated resin particles can be used.

With respect to the constitution of the coating layer of the developer carrying member of the present invention, the effect of the present invention can be obtained by simultaneously containing the spherical particles (A) and the fibrous particles (B) in the coating layer. .

The average fiber diameter BL of the fibrous particles (B) used in the present invention is within the range of 0.02≤BL / AL≤0.35, preferably 0.03≤BL / AL≤0.3. Within the range of.

Such fibrous particles (B) are dispersed and contained in the coating layer without deteriorating the uniform uneven shape of the surface of the coating layer formed by the shape factor of the spherical particles (A), Abrasion resistance of the surface of the coating layer is further improved, and finer and smoother unevenness is formed by the shape of the fibrous particles (B) itself in the uneven shape of the coating layer formed by the spherical particles (A). This is added in order to further prevent toner contamination and toner fusion on the surface of the coating layer.

The average fiber diameter BL of the fibrous particles (B) is 0.
If 02> BL / AL, the abrasion resistance cannot be improved by the addition of the fibrous particles (B), and it is difficult to form fine irregularities due to the shape of the fibrous particles (B) itself, so that toner contamination is caused. It is not preferable because fusion or adhesion easily occurs.

On the other hand, the average fiber diameter BL of the fibrous particles (B)
Is BL / AL> 0.35, the dispersibility of the fibrous particles (B) in the coating layer deteriorates, and the shape of the fibrous particles (B) causes unevenness of the coating layer surface. Therefore, the uniform charging to the toner and the strength of the coating layer become insufficient, which is not preferable.

In the present invention, the fibrous shape of the fibrous particles (B) means that the ratio of fiber length / fiber diameter (aspect ratio) has an elongated shape of about 7 to 140, preferably. It is preferable to use particles having an aspect ratio of 9 to 120.

If the aspect ratio of the fibrous particles (B) used in the present invention is less than 7, the abrasion resistance of the coating layer may not be sufficiently improved by adding the fibrous particles (B),
Not preferable.

On the other hand, when the aspect ratio of the fibrous particles (B) exceeds 140, the dispersibility of the fibrous particles (B) in the coating layer tends to deteriorate, and the fibrous particles (B) are coated with the shape of the fibrous particles (B). The unevenness of the layer surface may become uneven, which is not preferable.

The average fiber diameter BL of the fibrous particles (B) used in the present invention is 0.1 to 8 μm, preferably 0.2 to 5 μm. When the average fiber diameter BL of the fibrous particles (B) used in the present invention is less than 0.1 μm,
The addition of the fibrous particles (B) may not sufficiently improve the abrasion resistance of the coating layer, which is not preferable. On the other hand, if the average fiber diameter BL of the fibrous particles (B) exceeds 8 μm, unevenness on the surface of the coating layer may become uneven depending on the shape of the fibrous particles (B), which is not preferable.

As the composition of the fibrous particles (B) added to the coating layer, various materials can be used.
For example, potassium titanate whiskers, wollastonite, basic magnesium sulfate, sepiolite, zonotolite, acicular titanium oxide, graphite whiskers, silicon carbide whiskers, silicon nitride whiskers, boron carbide whiskers, alumina whiskers, aluminum borate whiskers, beryllium oxide whiskers. , Zirconia whiskers, carbon fiber, aromatic polyamide whiskers, poly (p
-Oxybenzoyl) whiskers, poly (2-oxy-)
6-naphthoyl) whiskers and the like can be used.
Since the fibrous particles (B) adjust the resistance of the coating layer,
It can also be used after being subjected to a conductive treatment with carbon, metal, metal oxide or the like.

As the binder resin material for the coating layer, generally known resins can be used. For example, styrene resin,
Thermoplastic resin such as vinyl resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluororesin, fiber resin, acrylic resin; epoxy resin, polyester resin, alkyd resin, phenol resin, melamine resin A heat- or photo-curable resin such as polyurethane resin, urea resin, silicone resin, or polyimide resin can be used. Above all, it has excellent releasability such as silicone resin and fluororesin, or excellent mechanical properties such as polyether sulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin, and acrylic resin. More preferred are:

As a constitution of the coating layer of the developer carrying member of the present invention, it is preferable to further disperse a conductive substance in the coating layer to form a conductive coating layer because the effect of the present invention is promoted. . As such a conductive substance, the number average particle diameter is preferably 1 μm or less.

When the number average particle diameter exceeds 1 μm, it is difficult to uniformly disperse the conductive substance in the coating layer, the chargeability of the toner becomes non-uniform, and the strength of the coating layer tends to decrease, which is preferable. Absent.

The conductive material used in the present invention includes carbon black such as furnace black, lamp black, thermal black, acetylene black, and channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, Examples thereof include metal oxides such as potassium titanate, antimony oxide and indium oxide; metals such as aluminum, copper, silver and nickel; and inorganic fillers such as graphite, metal fibers and carbon fibers.

The volume resistance of the coating layer of the developer carrying member of the present invention is preferably 10 ³ Ω · cm or less. When the volume resistance of the coating layer exceeds 10 ³ Ω · cm, charge-up of toner is likely to occur, which may cause deterioration of ghost and decrease in density.

Further, as the constitution of the coating layer of the developer carrying member of the present invention, it is preferable to further disperse a lubricating substance in the coating resin layer because the effect of the present invention is further promoted. Examples of the lubricating substance include graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and fatty acid metal salts such as zinc stearate.
Particularly, graphite is preferably used because it does not impair the conductivity of the coating layer. The number average particle diameter of these lubricating substances is preferably 0.2 to 20 μm.

Next, the structure of the developer carrying member used in the present invention will be described. The developer carrier comprises a metal cylindrical tube and a resin layer surrounding and covering the metal cylindrical tube. As the metal cylindrical tube, stainless steel, aluminum or the like is preferably used.

Next, the composition ratio of each component used in the coating layer will be described. The following are particularly preferable ranges.

The addition amount of the spherical particles (A) in the coating layer used in the present invention is in the range of 2 to 100 parts by mass with respect to 100 parts by mass of the binder resin, which gives particularly preferable results.
If it is less than 2 parts by mass, the effect of adding the spherical particles (A) is small,
If it exceeds 100 parts by mass, the chargeability of the toner may become too low.

The addition amount of the fibrous particles (B) in the coating layer used in the present invention is in the range of 20 to 800 parts by mass with respect to 100 parts by mass of the spherical particles, which gives particularly preferable results. When it is less than 20 parts by mass, the effect of adding the fibrous particles (B) is small, and when it exceeds 800 parts by mass, the uneven shape formed on the surface of the coating layer by the spherical particles (A) becomes non-uniform, so that the toner is uniformly charged. Is difficult to perform, and the strength of the coating layer is insufficient, which is not preferable.

The addition amount of the lubricating substance in the coating layer used in the present invention is 10 with respect to 100 parts by mass of the binder resin.
A range of ˜120 parts by weight gives particularly favorable results. 1
If it exceeds 20 parts by mass, the film strength and the amount of charge of the toner decrease. Contamination may occur easily.

The amount of the conductive substance added to the coating layer used in the present invention is 40 with respect to 100 parts by mass of the binder resin.
Particularly preferable results are obtained in the range of not more than parts by mass. If it exceeds 40 parts by mass, the film strength and the toner charge amount decrease.

In the present invention, as the roughness of the surface of the coating layer, the center line average roughness (hereinafter referred to as “Ra”) is preferably in the range of 0.2 to 4.5 μm, more preferably. Is preferably in the range of 0.4 to 3.5 μm.
If Ra on the surface of the coating layer is less than 0.2 μm, the toner transportability may be deteriorated and a sufficient image density may not be obtained. If it exceeds 4.5 μm on the surface of the coating layer, the amount of toner transported may be too large. Cannot be sufficiently charged, which is not preferable.

The thickness of the coating layer having the above structure is preferably 25 μm or less, more preferably 20 μm or less,
It is more preferably 4 to 20 μm to obtain a uniform film thickness, but it is not particularly limited to this film thickness. These film thicknesses depend on the material used for the coating layer, but the adhesion weight is 4000 to 20000 mg / m ²
You can get it by setting the degree.

Next, the developing device, the image forming apparatus and the process cartridge of the present invention, in which the above-described developer carrying member of the present invention is incorporated, will be described.

FIG. 1 is a schematic view of a developing device of one embodiment having the developer carrying member of the present invention.

In FIG. 1, an electrostatic latent image holding member for holding an electrostatic latent image formed by a known process, for example, the electrophotographic photosensitive drum 1 is rotated in the unmarked B direction. The developing sleeve 8 serving as a developer carrying member carries the one-component developer 4 having magnetic toner supplied by the hopper 3 serving as a developer container, and rotates in the direction of arrow A so that The developer 4 is conveyed to the developing area D facing the photosensitive drum 1. As shown in FIG. 1, the developer 4 is placed inside the developing sleeve 8.
A magnet roller 5 in which a magnet is inscribed is arranged for magnetic attraction and holding.

The developing sleeve 8 used in the developing device of the present invention has a coating layer 7 coated on a metal cylindrical tube 6 as a substrate. A stirring blade 10 for stirring the developer 4 is provided in the hopper 3. Reference numeral 12 is a gap indicating that the developing sleeve 8 and the magnet roller 5 are not in contact with each other.

The developer 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction between the magnetic toners and the coating layer 7 on the developing sleeve 8. In the example of FIG. 1, in order to regulate the layer thickness of the developer 4 conveyed to the developing area D, a magnetic regulation blade 2 made of a ferromagnetic metal as a developer layer thickness regulating member is provided from the surface of the developing sleeve. It is suspended from the hopper 3 so as to face the developing sleeve 8 with a gap width of 50 to 500 μm.
By concentrating the magnetic force lines from the magnetic pole N1 of the magnet roller 5 on the magnetic regulation blade 2, a thin layer of the developer 4 is formed on the developing sleeve 8. In the present invention, a non-magnetic blade may be used instead of the magnetic regulation blade 2.

Thus, the thin layer of the developer 4 formed on the developing sleeve 8 is thinner than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing area D. It is preferable.

The developer carrying member of the present invention is particularly effective when incorporated in a developing device of the type in which an electrostatic latent image is developed by a thin layer of the developer as described above, that is, a non-contact type developing device. In the developing area D, the developer carrier of the present invention is also applied to a developing device in which the thickness of the developer layer is not less than the minimum gap between the developing sleeve 8 and the photosensitive drum 1, that is, a contact type developing device. can do.

In order to avoid complication of the description, the non-contact type developing device as described above will be taken as an example in the following description.

In order to fly the one-component developer 4 having magnetic toner carried on the developing sleeve 8, a developing bias voltage is applied to the developing sleeve 8 by a developing bias power source 9 as a bias means. 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 developer 4 is adhered and visualized) of the electrostatic latent image and the potential of the background portion is applied to the developing sleeve. 8 is preferably applied.

In order to increase the density of the developed image or improve the gradation, an alternating bias voltage is applied to the developing sleeve 8 to form an oscillating electric field in which the direction is alternately inverted in the developing area D. May be. In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having an intermediate value between the potential of the developed image portion and the potential of the background portion is superimposed.

In the case of so-called normal development, in which toner is attached to the high potential portion of the electrostatic latent image having the high potential portion and the low potential portion to make it visible, that is, in the case of so-called normal development, the electrostatic latent image is charged to the opposite polarity. Use toner.

In the case of so-called reversal development, in which toner is visualized by attaching toner to the low potential portion of the electrostatic latent image having the high potential portion and the low potential portion, the toner is charged to the same polarity as the polarity of the electrostatic latent image. Use toner.

The high potential and the low potential are expressed by absolute values. In either case, the developer 4
Is charged at least by friction with the developing sleeve 8.

FIG. 2 is a schematic configuration diagram showing another embodiment of the developing device of the present invention, and FIG. 3 is a schematic configuration diagram showing still another embodiment of the developing device of the present invention.

In the developing device shown in FIGS. 2 and 3, a material having rubber elasticity such as urethane rubber or silicone rubber is used as a developer layer thickness regulating member for regulating the layer thickness of the developer 4 on the developing sleeve 8. Alternatively, an elastic regulating blade 11 made of an elastic plate made of a material having metallic elasticity such as phosphor bronze or stainless steel is used.
In this developing device, the developing sleeve 8 is pressed in the direction opposite to the rotating direction of the developing sleeve 8. In the developing device of FIG. 3, the elastic regulating blade 11 is pressed in the rotating direction of the developing sleeve 8 in the forward direction. Is characteristic.

In these developing devices, a thin layer of developer is formed on the developing sleeve 8 by elastically pressing the developer layer thickness regulating member against the developing sleeve 8 via the developer layer. Therefore, it is possible to form a thinner developer layer on the developing sleeve 8 than in the case of FIG.

The other basic structure of the developing device of FIGS. 2 and 3 is the same as that of the developing device shown in FIG. 1, and those having the same reference numerals basically indicate the same members.

1 to 3 merely schematically illustrate the developing device of the present invention, and there are various forms in the shape of the developer container (hopper 3), the presence or absence of the stirring blade 10, and the arrangement of the magnetic poles. Needless to say. Of course, these devices can also be used for development using a two-component developer containing toner and carrier.

An example of an image forming apparatus using the developing device of the present invention illustrated in FIG. 3 will be described with reference to FIG.

First, the surface of the photosensitive drum 101 serving as an electrostatic latent image holding member is negatively charged by the contact (roller) charging unit 119 serving as a primary charging unit, and the digital latent image is formed by image scanning by the laser light exposure 115. Are formed on the photosensitive drum 101. Next, by the developing device having the elastic regulating blade 111 as the developer layer thickness regulating member and the developing sleeve 108 as the developer carrying member in which the multi-pole permanent magnet 105 is included, the above digital device is used. The latent image is reversely developed by the one-component developer 104 having magnetic toner in the hopper 103. As shown in FIG. 4, in the developing area D, the conductive substrate of the photosensitive drum 101 is grounded, and the developing sleeve 1
08 is an alternating bias by the bias applying means 109,
A pulse bias and / or a DC bias is applied. Next, when the recording material P is conveyed and reaches the transfer portion, the contact (roller) transfer means 113 as a transfer means charges the recording material P from the back surface (the surface opposite to the photosensitive drum side) by the voltage applying means 114. As a result, the photosensitive drum 10
The developed image (toner image) formed on the surface of No. 1 is transferred onto the recording material P by the contact transfer means 113. Next, the recording material P separated from the photosensitive drum 101 is conveyed to a heating and pressure roller fixing device 117 as fixing means, and the fixing device 117 performs a fixing process of the toner image on the recording material P. .

The one-component developer 104 remaining on the photosensitive drum 101 after the transfer process is the cleaning blade 118.
It is removed by the cleaning means 118 having a. When the amount of the remaining one-component developer 104 is small, the cleaning process can be omitted. If necessary, the photosensitive drum 101 after cleaning is erased by erase exposure 116, and the above steps starting from the charging step by the contact (roller) charging means 119 as the primary charging means are repeated.

In the above series of steps, the photosensitive drum (that is, the electrostatic latent image carrier) 101 has a photosensitive layer and a conductive substrate, and moves in the arrow direction. The non-magnetic cylindrical developing sleeve 108, which is a developer carrying member, rotates in the developing area D so as to proceed in the same direction as the surface of the photosensitive drum 101. Inside the developing sleeve 108, a multi-pole permanent magnet (magnet roll) 105, which is a magnetic field generating means, is arranged so as not to rotate. The one-component developer 104 in the developer container 103 is applied and carried on the developing sleeve 108, and due to friction with the surface of the developing sleeve 108 and / or friction between the magnetic toners, for example, a negative triboelectric charge. Is given. Further, the elastic regulating blade 111 is provided so as to elastically press the developing sleeve 108, and the thickness of the developer layer is thin (30 μm to 300 μm).
In addition, the photosensitive drum 1 in the developing area D is regulated uniformly.
A developer layer thinner than the gap between 01 and the developing sleeve 108 is formed. By adjusting the rotation speed of the developing sleeve 108, the surface speed of the developing sleeve 108 is made substantially equal to or close to the surface speed of the photosensitive drum 101. In the developing area D, an AC bias or a pulse bias may be applied to the developing sleeve 108 as a developing bias voltage by the bias applying unit 109. This AC bias f is 200-
It may be 4,000 Hz and Vpp may be 500 to 3000V.

Developer (magnetic toner) in the development area D
At the time of transfer, the magnetic toner transfers to the electrostatic latent image side due to the electrostatic force on the surface of the photosensitive drum 101 and the action of a developing bias voltage such as an AC bias or a pulse bias.

Instead of the elastic regulation blade 111, it is also possible to use a magnetic doctor blade such as iron.

As the primary charging means, the charging roller 119 is used as the contact charging means as described above.
A contact charging means such as a charging blade or a charging brush may be used, or a non-contact corona charging means may be used. However, the contact charging means is preferable in that ozone is less generated by charging.

As the transfer means, the contact transfer means such as the transfer roller 113 has been described above, but a non-contact corona transfer means may be used. However,
Also in this case, the contact transfer means is preferable in that ozone is less generated by the transfer.

FIG. 5 shows a specific example of the process cartridge of the present invention.

In the following description of the process cartridge, components having the same functions as the components of the image forming apparatus described with reference to FIG. 4 will be described using the same reference numerals as those in FIG.

The process cartridge of the present invention is one in which at least the developing means and the electrostatic latent image holder are integrally formed into a cartridge, and the image forming apparatus main body (for example, a copying machine, a laser beam printer, a facsimile machine).
It is configured to be removable.

In the embodiment shown in FIG. 5, the developing means 12
0, a drum-shaped electrostatic latent image holder (photosensitive drum) 101,
A process cartridge 150 in which a cleaning unit 118 having a cleaning blade 118a and a contact (roller) charging unit 119 as a primary charging unit are integrated is exemplified.

In this embodiment, the developing means 120 has an elastic regulating blade 111 and a one-component developer 104 having magnetic toner in the developer container 103.
During development, a predetermined electric field is formed between the photosensitive drum 101 and the developing sleeve 108 by the developing bias voltage from the bias applying means, and the developing process is performed.
In order to suitably carry out this developing step, the photosensitive drum 10
The distance between 1 and the developing sleeve 108 is very important.

In the above, the developing means 120, the electrostatic latent image holding member 101, the cleaning means 118 and the primary charging means 1 are used.
Although the embodiment in which the four components of 19 are integrated into a cartridge has been described, in the present invention, at least two components of the developing unit and the electrostatic latent image holding member are integrated into a cartridge. 3 components including a developing unit, an electrostatic latent image holding member, and a cleaning unit, a developing unit, an electrostatic latent image holding member, and a primary charging unit.
It is also possible to add one component or other components to integrally form a cartridge.

Next, the developer (toner) used to obtain a visible image from the electrostatic latent image in the present invention will be described.

The toner contained in the developer is roughly classified into a dry toner and a wet toner. However, since the wet toner has a large problem of solvent volatilization, the dry toner is predominant at present. A toner is a fine powder in which materials such as a binder resin, a release agent, a charge control agent, and a coloring agent are melt-kneaded, the melt is cooled and solidified, and then crushed, and then classified to classify the particle size distribution. It is the body.

The binder resin used in the toner is, for example, a homopolymer of styrene such as styrene, α-methylstyrene, p-chlorostyrene and a substituted product thereof; a styrene-propylene copolymer and a styrene-vinyltoluene copolymer. Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl copolymer, styrene-methyl methacrylate copolymer, styrene- Ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer Coal, styrene-isoprene copolymer, styrene Styrene-based copolymers such as styrene-maleic acid copolymer and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene polyvinyl butyral, polyacrylic acid resin, rosin, modified Rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin wax, carnauba wax and the like can be used alone or in combination.

When the toner is used as a color toner (non-magnetic toner), the toner may contain a pigment as a colorant. Examples of pigments include carbon black, nigrosine dye, lamp black, Sudan black SM, fast yellow G, benzidine yellow, pigment yellow, indo first orange, irgadine red, paranitroaniline red, toluidine red. , Carmin FB, Permanent Bordeaux FRR, Pigment Orange R, Resor Red 2G, Rake Red C, Rhodamine FB,
Rhodamine B Lake, Methyl Violet B Lake,
Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, Pomelo First Yellow CGG, Kayaset Y963, Kayaset YG, Pomelo First Orange RR, Oil Scarlet, Orazol.
Examples include brown B, pomelo first scarlet CG, and oil pink OP, which can be appropriately selected and used.

When the toner is used as a magnetic toner, magnetic powder is contained in the toner. As such magnetic powder, a substance magnetized in a magnetic field is used. As the magnetic powder, for example, iron, cobalt,
Powder of ferromagnetic metal such as nickel, or magnetite,
Examples include alloys and compounds such as hematite and ferrite. The content of these magnetic powders is preferably about 15 to 70 mass% with respect to the toner mass.

There are cases where various releasing agents are added to the toner to be contained. Examples of such releasing agents include polyfluorinated ethylene, fluororesin, fluorocarbon oil, silicone oil, low molecular weight polyethylene, and low molecular weight polyethylene. Examples include molecular weight polypropylene and various waxes. Further, if necessary, various charge control agents may be added to facilitate positive or negative charging.

In the present invention, the non-magnetic toner may be mixed with a carrier and used as a two-component developer.
Alternatively, it can be used as a non-magnetic one-component developer without being mixed with a carrier.

The methods for measuring physical properties relating to the present invention will be described below.

(1) Measurement of center line average roughness (Ra) Based on the surface roughness of JIS B0601, a surf coder SE-3300 manufactured by Kosaka Laboratory was used to measure 3 points in the axial direction × 2 points in the circumferential direction = 6 points. Each was measured and the average value was taken. The measurement condition is a feed speed of 0.5 mm.
/ Sec, measurement length 2.5 mm, roughness cutoff λc =
It was measured at 0.8 with auto leveling on.

(2) Measurement of volume resistance of coating layer A coating layer having a thickness of 7 to 20 μm was formed on a PET sheet having a thickness of 100 μm, and the ASTM standard (D-991-8) was used.
2) and Japan Rubber Association standard SRIS (2301-
1969), using a voltage drop type digital ohmmeter (manufactured by Kawaguchi Denki Seisakusho) provided with electrodes having a four-terminal structure for measuring the volume resistance of conductive rubber and plastic. The measurement environment is 20 to 25 ° C and 50 to 60 RH.
%.

(3) Particle Size Measurement of Spherical Particles (A) The number average particle size was calculated using a Coulter LS-130 particle size distribution meter (manufactured by Beckman Coulter Inc.), which is a laser diffraction type particle size distribution meter, and calculated from the number distribution. I asked.

(4) Measurement of Fiber Average Diameter and Fiber Average Length of Fibrous Particles (B) The fiber diameter and length of the fibrous particles are measured using Hitachi FE-SEM (S-800). .

The photographing magnification is appropriately adjusted to 500 to 60,000 times for enlargement according to the size and length of the fiber diameter. The fiber diameter and length of the fibrous particles (B) are measured on the photograph. This was measured for 100 samples, and the 50% value was taken as the average fiber diameter and the average fiber length.

(5) Measurement of particle size of conductive fine particles The particle size of conductive fine particles is measured using FE-SEM (S-800) manufactured by Hitachi Ltd. The photographing magnification is 60,000 times, but if difficult, the photograph is enlarged at a low magnification and then the photograph is enlarged to 60,000 times. The particle size of the primary particles is measured on the photograph. At this time, the major axis and the minor axis are measured, and the averaged value is taken as the particle size. This is measured for 100 samples and 50
The% value is taken as the average particle size.

(6) Measurement of Toner Particle Size Measurement was carried out using a Coulter Counter Multisizer (manufactured by Coulter Co.) to obtain a weight-based weight average diameter obtained from the volume distribution.

[0098]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the examples do not limit the present invention. In the examples and comparative examples, "%" and "parts" are based on mass unless otherwise specified.

Example 1 Crosslinked PMMA particles (A-1) having a number average particle diameter of 8.9 μm were used as spherical particles, and potassium titanate (B-1) was used as fibrous particles. The physical properties of each particle are shown in Tables 1 and 2. Resol type phenolic resin solution (containing 50% methanol) 200 parts Graphite having a number average particle size of 3.6 μm 52 parts Conductive carbon black 6 parts Isopropyl alcohol 120 parts

Zirconia beads having a diameter of 1 mm were added to the above materials as media particles and dispersed in a sand mill for 2 hours, and the beads were separated by using a sieve to obtain a stock solution of coating material.

Next, spherical particles A-1 were added to 378 parts of the above stock solution.
12 parts, and 15 parts of fibrous particles B-1 were added, and isopropyl alcohol was added so that the solid content concentration became 32%, followed by dispersing for 20 minutes using glass beads having a diameter of 1 mm, and using a sieve. The beads were separated to obtain a coating liquid.

Using this coating solution, a coating layer was formed on a cylindrical aluminum tube having an outer diameter of 16 mmφ by a spray method, and subsequently, the coating layer was cured by heating at 150 ° C. for 30 minutes in a hot air drying oven to develop the coating layer. The agent carrier C-1 was produced.

The adhesion weight of the coating layer after drying was 9520 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-1.

A laser beam printer Laser Jet III Si is used as the image forming apparatus shown in FIG. 4 in which the C-1 developer carrier is applied to the developing apparatus shown in FIG.
While supplying a one-component developer using (made by Hewlett Packard), a durability evaluation test of the developer carrying member was performed.

The following were used as the one-component type developer. Styrene-acrylic resin 100 parts Magnetite 100 parts Charge control agent 2 parts Low molecular weight polypropylene 4 parts

The above-mentioned materials were kneaded, pulverized and classified according to a general dry toner production method to give a number average particle diameter of 6.3 μm.
m fine powder was obtained. To 100 parts of this fine powder, 1.0 part of hydrophobic colloidal silica was externally added to obtain a magnetic toner, and the magnetic toner was used as a one-component developer.

In the image forming apparatus used in this embodiment, a process cartridge in which an electrostatic latent image holding member, a developing means, a cleaning means and a primary charging means are integrally made into a cartridge is detachably attached to the main body of the image forming apparatus. 5 has the configuration shown in FIG.

<Example 2> 12 parts of spherical particles A-1 and 20 parts of fibrous particles B-2 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-2 was prepared in the same manner as in 1.

The adhesion weight of the coating layer after drying was 9340 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-2.

Using the developer carrier of C-2 in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 1. .

<Example 3> 12 parts of spherical particles A-1 and 10 parts of fibrous particles B-3 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-3 was prepared in the same manner as in 1.

The dry weight of the coating layer was 9650 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-3.

Using the developer carrier of C-3 in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 1. .

<Example 4> 12 parts of spherical particles A-1 and 15 parts of fibrous particles B-4 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-4 was prepared in the same manner as in 1.

The adhesion weight of the coating layer after drying was 9500 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-4.

Using the developer carrier of C-4 in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 1. .

<Example 5> 12 parts of spherical particles A-1 and 15 parts of fibrous particles B-5 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-5 was prepared in the same manner as in 1.

The coating weight after drying was 9320 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-5.

Using the C-5 developer carrier in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 1. .

Example 6 Example 3 was repeated except that 3 parts of spherical particles A-2 and 10 parts of fibrous particles B-3 shown in Table 1 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-6 was produced in the same manner as in 1.

The dry weight of the coating layer was 9670 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-6.

Using the C-6 developer carrier in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 1. .

<Example 7> 12 parts of spherical particles A-3 and 15 parts of fibrous particles B-4 shown in Table 2 were added to 378 parts of the undiluted solution of the coating material prepared in Example 1. A developer carrying member C-7 was produced in the same manner as in 1.

The coating weight of the dried coating layer was 9530 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-7.

A C-7 developer carrier was used in the same image device as in Example 1, and a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 1. .

<Example 8> 12 parts of spherical particles A-1 and 15 parts of fibrous particles B-6 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-8 was prepared in the same manner as in 1.

The adhesion weight of the coating layer after drying was 9480 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-8.

A C-8 developer carrier was used in the same image apparatus as in Example 1, and a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 1. .

Example 9 Example 9 was repeated except that 12 parts of spherical particles A-1 and 20 parts of fibrous particles B-7 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-9 was produced in the same manner as in 1.

The dry weight of the coating layer was 9350 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-9.

Using the C-9 developer carrier in the same image device as in Example 1, a durability evaluation test of the developer carrier was conducted while supplying a one-component developer in the same manner as in Example 1. .

Example 10 Example 3 was repeated except that 3 parts of spherical particles A-2 and 10 parts of fibrous particles B-8 shown in Table 2 were added to 378 parts of the stock solution of the coating material prepared in Example 1. A developer carrying member C-10 was produced in the same manner as in 1.

The coating weight of the dried coating layer was 9510 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-10.

A C-10 developer carrier was used in the same image device as in Example 1, and a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 1. .

<Example 11> 10 parts of spherical particles A-4 shown in Table 1 were added to 378 parts of the stock solution of the coating material prepared in Example 1.
A developer carrying member C-11 was produced in the same manner as in Example 1 except that 15 parts of the fibrous particles B-6 were added.

The dry weight of the coating layer was 9480 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-11.

Using the C-11 developer carrier in the same image device as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 1. .

<Example 12> Resol-type phenol resin solution (containing 50% methanol) 200 parts 54 parts of graphite with a number average particle size of 1.7 μm Conductive carbon black 6 parts Isopropyl alcohol 120 parts

Zirconia beads having a diameter of 1 mm were added to the above materials as media particles and dispersed in a sand mill for 2 hours, and the beads were separated using a sieve to obtain a stock solution of coating material.

Next, 4 parts of spherical particles A-5 and 15 parts of fibrous particles B-6 shown in Table 1 were added to 380 parts of the above stock solution,
Add isopropyl alcohol to a solids concentration of 32%, and then add 2 mm using glass beads with a diameter of 1 mm.
The mixture was dispersed for 0 minutes, and the beads were separated using a sieve to obtain a coating liquid.

Using this coating solution, a coating layer was formed on a cylindrical aluminum tube having an outer diameter of 32 mmφ by a spray method, followed by heating in a hot air drying oven at 150 ° C. for 30 minutes to cure the coating layer and develop it. The agent carrier C-12 was produced.

The dry weight of the coating layer after drying was 9510 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member C-12.

The C-12 developer carrier was used in the image forming apparatus (corona charging means, corona transfer means) NP6060 (manufactured by Canon Inc.) having the developing device shown in FIG. 1 to prepare a one-component developer. While supplying, a durability test of the developer carrying member was performed.

The following were used as the one-component type developer. Polyester resin 100 parts Magnetite 100 parts 3,5-di-tert-butyl chromium salicylate complex 2 parts Low molecular weight polypropylene 4 parts

The above materials were kneaded, pulverized and classified according to a general dry toner production method to give a number average particle diameter of 6.6 μm.
m fine powder was obtained. 1.2 parts of hydrophobic colloidal silica was externally added to 100 parts of this fine powder to obtain a magnetic toner, and this magnetic toner was used as a one-component developer.

<Comparative Example 1> Except that the fibrous particles B-1 were not added to 378 parts of the stock solution of the coating material prepared in Example 1.
A developer carrying member D-1 was prepared in the same manner as in Example 1.

The dry weight of the coating layer was 9540 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member D-1.

Using the developer carrying member D-1 in the same image device as in Example 1, a durability evaluation test of the developer carrying member was carried out while supplying a one-component developer as in Example 1. .

Comparative Example 2 Fibrous particles B-3 without adding spherical particles to 378 parts of the stock solution of the coating material prepared in Example 1
A developer carrying member D-2 was prepared in the same manner as in Example 1 except that 25 parts of was added.

The adhesion weight of the coating layer after drying was 9750 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member D-2.

Using the developer carrier D-2 in the same image device as in Example 1, a durability evaluation test of the developer carrier was conducted while supplying a one-component developer in the same manner as in Example 1. .

<Comparative Example 3> In 378 parts of the stock solution of the coating material prepared in Example 1, instead of spherical particles A-1, non-spherical graphite particles a- having a number average particle size of 17.2 μm shown in Table 1- A developer carrying member D-3 was produced in the same manner as in Example 1 except that 12 parts of 1 was added.

The adhesion weight of the coating layer after drying was 9500 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member D-3.

Using the developer bearing member D-3 in the same image apparatus as in Example 1, a durability evaluation test of the developer bearing member was carried out while supplying a one-component developer as in Example 1. .

Comparative Example 4 Fibrous particles B-1 without adding spherical particles to 378 parts of the stock solution of the coating material prepared in Example 1
A developer carrying member D-4 was prepared in the same manner as in Example 1 except that 10 parts of non-fibrous potassium titanate b-1 shown in Table 2 was added.

The dry weight of the coating layer was 9450 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member D-4.

Using the developer carrier of D-4 in the same image apparatus as in Example 1, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 1. .

Comparative Example 5 A developer carrying member D-5 was prepared in the same manner as in Example 12 except that spherical particles were not added to 380 parts of the stock solution of the coating material prepared in Example 12.

The dry weight of the coating layer was 9690 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of this developer carrying member D-5.

Using the developer carrier of D-5 in the same image apparatus as in Example 12, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer as in Example 12. .

Comparative Example 6 A developer carrier D-6 was prepared in the same manner as in Example 12 except that fibrous particles were not added to 380 parts of the stock solution of the coating material prepared in Example 12.

The dry weight of the coating layer was 9650 mg.
/ M ² . Table 3 shows the physical properties of the coating layer of the developer carrying member D-6.

Using the developer carrier D-6 in the same image device as in Example 12, a durability evaluation test of the developer carrier was carried out while supplying a one-component developer in the same manner as in Example 12. .

[Evaluation] Durability tests were carried out on the evaluation items listed below, and the developer carrying members of Examples and Comparative Examples were evaluated. Table 4 shows the evaluation results of durability of image density, durability fog and durability ghost under low temperature and low humidity.
Further, Table 5 shows the durability of image density under high temperature and high humidity,
The evaluation results of durability fog and durability ghost are shown. Furthermore, the evaluation results of abrasion resistance and stain resistance are shown.

As a durable environment, low temperature / low humidity (L / L)
Two endurance environments under high temperature and high humidity (H / H) were performed. Specifically, under low temperature / low humidity (L / L),
In an environment of 15 ° C / 10% RH, high temperature / high humidity (H /
H) bottom was 32.5 ° C./85% RH.

<Evaluation Method> (1) Image Density Image density was measured using a reflection densitometer RD918 (manufactured by Macbeth Co.) to measure the density of solid black portions at the time of solid printing, and the average value was used as the image density. And

(2) Fog Density The reflectance (Dl) of the solid white portion of the recording paper on which an image has been formed is measured, and the reflectance (D2) of an unused recording paper of the same cut as the recording paper used for image formation is measured. ) Was measured, the value of D1-D2 was obtained at 5 points, and the average value was taken as the fog density. The reflectance was measured by TC-6DS (manufactured by Tokyo Denshoku Co., Ltd.).

(3) The halftone image is developed so that the position of the developing sleeve for developing the image in which the ghost solid white portion and the solid black portion are adjacent to each other comes to the developing position when the developing sleeve is rotated next time, and the halftone image is developed. The density difference appearing on the image was visually evaluated according to the following criteria. ○: No difference in light and shade is seen. ○ △: A slight difference in shade is seen. Δ: Practical is acceptable although there is a slight difference in shade. Poor: Practical use is not possible because the difference in light and shade is remarkable.

(4) Abrasion resistance of coating layer The arithmetic mean roughness (Ra) of the surface of the developer carrying member was measured before and after the durability test.

(5) Contamination resistance of the coating layer The surface of the developer bearing member after the durability test was observed by SEM, and the degree of toner contamination was evaluated according to the following criteria. ○: Minor contamination is observed. ○ △: Some contamination is observed. Δ: Contamination is partially observed. X: Significant contamination is observed.

[0171]

[Table 1]

[0172]

[Table 2]

[0173]

[Table 3]

[0174]

[Table 4]

[0175]

[Table 5]

[0176]

[Table 6]

[0177]

As described above, according to the present invention,
The durability is improved as compared with the conventionally used developer carrier, and it becomes possible to maintain a state in which a good image can be provided for a long time. Therefore, according to the present invention, due to the highly durable developer carrier that does not cause deterioration such as abrasion and toner contamination of the coating layer on the surface of the developer carrier due to repeated copying or durability, image density reduction and ghost generation,
It is possible to provide high-quality images for a long period of time without deterioration of fog.

[Brief description of drawings]

FIG. 1 is a schematic view of a developing device according to an embodiment having a developer carrying member on which a coating layer of the present invention is formed.

FIG. 2 is a schematic view of a developing device according to another embodiment of the present invention, in which the developing layer regulating member of the developing device shown in FIG. 1 is different.

FIG. 3 is a schematic view of a developing device according to another embodiment of the present invention in which the developing layer regulating member of the developing device of FIG. 1 is different.

FIG. 4 is a schematic explanatory view of an image forming apparatus of the present invention.

FIG. 5 is a schematic explanatory view of a specific example of the process cartridge of the present invention.

FIG. 6 is a schematic view of a conventional developing device having a developer carrying member on which a coating layer is not formed.

[Explanation of symbols]

1 Photosensitive drum (electrostatic latent image holder) 2 Magnetic regulation blade 3 hopper (developer container) 4 Developer (toner) 5 magnet roller 6 Metal Cylindrical Tube 7 Conductive resin coating layer 8 developing sleeve 9 Development bias power supply 10 stirring blades 11 Elasticity regulation blade 12 gap 101 photosensitive drum 103 developer container 104 One-component developer 105 Multi-pole permanent magnet 108 Development sleeve 109 Bias applied voltage 111 Elasticity regulation blade 113 Contact (roller) transfer means 114 voltage applying means 115 exposure 116 erase exposure 118 Heat and pressure roller fixing device 118 cleaning means 118a cleaning blade 119 Contact (roller) charging means 120 developing means N1, N2, S1, S2 magnetic poles A Development sleeve rotation direction B Photosensitive drum rotation direction D development area P Recording material

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Michiko Orihara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Kenji Fujishima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. Within the corporation (56) Reference JP-A-4-143780 (JP, A) JP-A 1-268759 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 G03G 15/09

Claims (8)

(57) [Claims] 1. A developer carrier having at least a substrate and a coating layer for coating the surface of the substrate , wherein the coating layer comprises a binder resin and spherical particles (A) dispersedly contained in the binder resin. The coating layer has at least fibrous particles (B), the volume resistance of the coating layer is 10 ³ Ω · cm or less, and the center line average roughness of the coating layer surface is 0.4 to 3.5 μm.
m, and the ratio of major axis / minor axis of the spherical particles (A) is 1.0 to 1.5.
And the number average particle size AL of the spherical particles (A) and the fibrous particles
The average fiber diameter BL of (B) is 0.02 ≦ BL / AL ≦
A developer carrying member satisfying 0.35 . 2. The developer carrying member according to claim 1, wherein the coating layer further contains conductive fine powder dispersed therein to form a conductive coating layer. 3. A spherical particles (A), number average particle diameter AL
Is in the range of 1 to 30 μm. 3. The developer carrier according to claim 1, wherein 4. The ratio of major axis / minor axis of the spherical particles (A) is
4. The developer carrier according to claim 1, wherein the developer carrier is 1.0 to 1.2 . 5. A process cartridge detachable from an image forming apparatus main body, wherein the process cartridge comprises (i) an electrostatic latent image holding member for holding an electrostatic latent image, and (ii) the electrostatic latent image. At least integrally with a developing means for developing with a developer in the developing area, the developing means includes a developer container for containing the developer, and the developing container accommodated in the developer container. It has a developer carrier for forming and carrying a thin layer of the developer on the surface and for transporting the developer to the developing region, the developer carrier at least covering the substrate and the substrate surface. in the developer carrying member having a coating layer, the coating layer may be spherical particles (a) and fibrous particles dispersed contained in a binder resin and the binder resin (B) at least Yes, the coating the volume resistivity of the layer is less at 10 ³ Ω · cm Ri, the center line average roughness of the coating layer surface is 0.4 to 3.5μ
m, and the ratio of major axis / minor axis of the spherical particles (A) is 1.0 to 1.5.
And the number average particle size AL of the spherical particles (A) and the fibrous particles
The average fiber diameter BL of (B) is 0.02 ≦ BL / AL ≦
A process cartridge satisfying 0.35 . 6. The process cartridge according to claim 5 , wherein the coating layer further contains conductive fine powder dispersed therein to form a conductive coating layer. 7. The spherical particles (A), number average particle diameter AL
Is in the range of 1 to 30 μm.
5. The process cartridge according to 5 or 6 . 8. The ratio of major axis / minor axis of the spherical particles (A) is
6. The method according to claim 5 , wherein the range is 1.0 to 1.2.
7. The process cartridge according to any one of 7 .