JP2003295480A - Image forming method, image forming apparatus, process cartridge and electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrophotographic image forming method and image forming apparatus in which trouble is not caused even when an electrifying stage is a system where an electrifying member is brought into contact with an electrophotographic photoreceptor, and a process cartridge and an electrophotographic photoreceptor used for the image forming method. <P>SOLUTION: In the image forming method for forming an image by using the electrophotographic photoreceptor having a coating layer on a cylindrical conductive base substance and repeating the electrifying stage, an exposure stage, a developing stage, a toner image transfer stage and a stage for removing toner remaining on the photoreceptor by a cleaning means, the shape of the end of the photoreceptor satisfies following expressions (1) and (2), and the electrifying member is brought into contact with the photoreceptor and electrifies it in the electrifying stage. The expression (1) is 0<Pmax<2P and the expression (2) is 2≤(Pmax/D)×100≤50. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, an image forming apparatus, and a process cartridge used in a copying machine, a laser beam printer, a facsimile, and the like.
The present invention relates to an electrophotographic photosensitive member (may be simply referred to as a photosensitive member) used for it.

[0002]

2. Description of the Related Art When a cylindrical electrophotographic photosensitive member (sometimes referred to as a photosensitive drum) is manufactured, a cylindrical conductive substrate is placed in a photosensitive layer liquid or an intermediate layer, or a coating liquid for a surface protective layer. It is common to form a coating layer by dipping.

In this case, since the cylindrical conductive substrate is immersed in the coating solution, the coating layer is formed on the entire surface of the cylindrical conductive substrate. When a photoconductor drum having a coating layer formed on the entire surface of a cylindrical conductive substrate is incorporated into an electrophotographic apparatus, the coating layer peels off due to contact with a roller or the like against which a developing device or the like is abutted, and a precise projection is performed. Since it may not be possible to apply it, or it may not be used as a contact for grounding the photosensitive drum, it is preferable to remove the coating layer adhered to both ends of the photosensitive drum.

As a method for removing this coating layer, the end of the photosensitive drum is immersed in a solvent and ultrasonically vibrated (Japanese Patent Laid-Open No. 63-311357), and a method of rubbing with a brush (Japanese Patent Laid-Open No. 3-60782). No. 4,141,663, No. 5,142,789, No. 10,20,708.
4, gazette 11-184100, gazette 11-19.
4509) and the like, there is also a removing method using a tape.

For example, a method of sequentially unwinding a tape made of a heat-fusion type nonwoven fabric, impregnating the tape with a solvent, and then contacting the tape with a photosensitive drum to remove the tape (Japanese Patent Publication No. 4-65376). Alternatively, a method of unwinding a tape made of a twill fabric impregnated with a solvent and then contacting the tape with a photoconductor drum to remove the tape (Japanese Patent Laid-Open No. 6-138670) is used. A method using a tape (Japanese Patent Laid-Open No. 9-281725) is known.

However, according to the analysis by the inventors, in any of the methods, the coating layer removal end of the photoconductor drum is easily peeled off, toner is not collected on the coating layer removal end, and cleaning of the interior of the apparatus due to toner scattering occurs. However, there is a problem that the durability of the photosensitive drum and the cleaning member (cleaning means) is eventually deteriorated due to these causes, and it is desired that the photosensitive drum is shaped so as not to cause such a failure. .

In addition, the electrophotographic image forming apparatus which is widely used in the market at present has at least a charging means, an image exposing means, a developing means, a transferring means, a cleaning means and a fixing means around an electrophotographic photosensitive member as an image holding member. .

The charging member typically used as a member of the above-mentioned charging means is a corona discharger. The corona charger has an advantage that stable charging can be performed. However, since a corona discharger needs to apply a high voltage, it produces a large amount of ionized oxygen, ozone, water, nitric oxide compounds, etc., which may lead to deterioration of the electrophotographic photoreceptor or adversely affect the human body. It has the potential to affect.

Therefore, recently, the use of a contact charging method which does not use a corona discharger has been studied. Specifically, a voltage is applied to a magnetic brush or a conductive roller, which is a charging member, to contact a photoreceptor, which is a member to be charged, to charge the surface of the photoreceptor to a predetermined potential. When such a contact charging method is used, the voltage can be lowered and the amount of ozone generated can be reduced as compared with the non-contact charging method using a corona discharger.

For this reason, the number of cases in which a contact charger that produces a small amount of ozone is adopted is increasing (for example, Japanese Unexamined Patent Publication No. 20-200200).
No. 02-196522), the amount of abrasion of the photosensitive layer is increased during repeated image formation, and in particular, excessive abrasion or peeling of the end portion of the coating layer is likely to occur.

Further, when repeatedly used especially in a high temperature and high humidity environment, toner adheres to and accumulates at the end of the coating layer of the photoconductor to change the physical properties of the surface, resulting in torque fluctuation between the cleaning blade and the photoconductor. Also, also by this, peeling of the end portion of the coating layer easily occurs. In particular, when peeling occurs, or when the toner that has agglomerated and adhered to the portion is mixed with the developer as a foreign substance, poor charging, poor cleaning, black spots, and the like may occur, resulting in deterioration of image quality.

[0012]

[Patent Document 1] Japanese Patent Laid-Open No. 9-281725

[0013]

[Patent Document 2] Japanese Patent Application Laid-Open No. 11-194509

[0014]

[Patent Document 3] Japanese Unexamined Patent Publication No. 2002-196522

[0015]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and an object thereof is to make the shape of the end portion of the coating layer of the photoconductor so as not to cause the above problems. To do.

That is, an object of the present invention is to provide a method in which the charging step involves charging the electrophotographic photosensitive member with a charging member in contact therewith,
The end shape of the electrophotographic photosensitive member is such that the end of the coating layer does not peel off, there is no toner accumulation, there are no defects such as black spots due to scattering of the coating layer powder or toner, and the electrophotographic image forming method and image It is to provide a forming apparatus and a process cartridge, and an electrophotographic photosensitive member used for the forming apparatus and the process cartridge.

[0017]

Means for Solving the Problems As a result of intensive studies by the inventors, it was found that the object of the present invention can be achieved by adopting any of the following constitutions.

[1] A charging step, an exposing step, a developing step using a developer containing toner, a toner image transferring step, an electron step, and an electronic step using an electrophotographic photoreceptor having a coating layer including at least a photosensitive layer on a cylindrical conductive substrate. In an image forming method in which an image is formed by repeating the step of removing the toner remaining on the photographic photosensitive member by a cleaning unit, the average value of the coating layer thickness at the central portion of the electrophotographic photosensitive member in the image forming width direction is P ( μ
m), the average of the maximum values of the film thickness outside the image forming area is Pma
x (μm), where D (μm) is the average value of the distance from the point where the maximum value is formed to the end of the coating layer, a shape that satisfies both formulas (1) and (2) below is obtained. The image forming method is characterized in that in the charging step, a charging member is brought into contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member. Formula (1) 0 <Pmax <2P Formula (2) 2 ≦ (Pmax / D) × 100 ≦ 50 [2] An electrophotographic photoreceptor in which a coating layer including at least a photosensitive layer is formed on a cylindrical conductive substrate. Of the excess coating layer is brought into contact with a rubbing means, and an electrophotographic photoreceptor from which the coating layer has been removed is used to form a toner image through a charging step, an exposure step, and a developing step with a developer containing toner, and then transferred to a transfer material. After that, in the image forming method in which the step of cleaning the remaining toner with a cleaning unit is repeated, the average value of the coating layer thickness in the central portion of the electrophotographic photosensitive member in the image forming width direction is P (μm) Let Pmax (μm) be the average of the maximum film thickness values at, and D (μm) be the average value of the distance from the point where the maximum value is formed to the end of the coating layer.
An image forming method having a shape that satisfies both of the following formulas (1) and (2), wherein the charging step is performed by bringing a charging member into contact with the surface of the electrophotographic photosensitive member to perform charging. Formula (1) 0 <Pmax <2P Formula (2) 2 ≦ (Pmax / D) × 100 ≦ 50 [3] The means used in the charging step is a charging roller [1] or [2] ] The image forming method described in.

[4] The image forming method as described in [1] or [2], wherein the means used in the charging step is a magnetic brush.

[5] The image forming method according to [2], wherein the rubbing means is a brush.

[6] The image forming method according to [2], wherein the rubbing means is a tape.

[7] The image forming method described in any one of [1] to [6], wherein the cleaning means is a urethane rubber cleaning blade.

[8] An image forming apparatus using the image forming method described in any one of [1] to [7].

[0024]

[9] Using the image forming apparatus according to the above [8], at least one of a charging unit, an exposing unit, a developing unit, a transferring unit, and a cleaning unit is combined with an electrophotographic photosensitive member and integrated with the main body of the image forming apparatus. A process cartridge characterized in that it is formed so that it can be taken in and out as desired.

[10] Any one of [1] to [7] above
An electrophotographic photoreceptor, which is used in the image forming method as described in the above item.

That is, by adopting the above-mentioned constitution, since the end portion of the coating layer of the electrophotographic photosensitive member is gentle, toner does not accumulate at the end portion, there is no toner contamination, and the adhesiveness of the end portion of the coating layer is good. It was found that an image forming method, an image forming apparatus, and an electrophotographic photosensitive member mounted therein, which have preferable characteristics such as no defect and good durability of the electrophotographic photosensitive member, can be obtained.

The coating layer is a charge-generating layer of a function-separated type photoreceptor, a photosensitive layer including a charge-transporting layer, an intermediate layer, a surface protective layer, and the like, and may be a cylindrical conductive substrate for the photoreceptor. Refers to all layers applied.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The requirements, members used, image forming apparatus, image forming method and the like in the present invention will be further described.

[1] Photoreceptor 1. Specified Values Used in the Present Invention First, the electrophotographic photosensitive drum and the specified values used in the present invention will be described with reference to FIG.

The photosensitive drum 3 has a shape as shown in the perspective view of FIG. 1 (a). A photosensitive layer is formed on the surface of the conductive substrate 1 having a drum shape, and an intermediate layer and a protective layer for the surface, if necessary. Is applied. It is desirable that both ends of the coating layer on the photoconductor drum be completely peeled off, and the shape of the ends is also extremely important.

Therefore, first, the method of measuring the average value P (μm) of the film thickness at the central portion of the photosensitive layer used in the definition of the present invention will be described.

The average value P of the film thickness in the central portion of the photosensitive layer is shown in FIG.
Explaining using (b), the central portion C and 3 cm from C
4 positions at right angles to each other in each cross section of C ₋₁ and C ₊₁ which are separated from each other, that is, C, Ca, Cb, Cd in FIG.
C ₊₁ a, C ₊₁ b, C ₊₁ c, C ₊₁ d, C _-1 a, C _-1 b, C
_-1 c and C _-1 d are measured at 12 points, and the average thereof is defined as the average value P of the film thickness in the central portion of the photosensitive layer. The film thickness measuring device used for the above film thickness measurement is an eddy current type film thickness measuring device EDDY56.
0C (HELMUT FISCHER GMBTE C
(Manufactured by O company) was used.

The film thickness profile at the edge of the photosensitive layer was measured by the continuous film thickness measurement method as described below.

The film thickness at the end of the coating layer is measured by scanning the measurement point in the axial direction of the substrate as shown in FIG. 1C, and one end of the coating layer is continuously measured. Measurement length L at this time
Must include an image forming area or a portion including the coating layer 2 area having the same film thickness as that shown in FIG. 1C and an exposed portion of the conductive substrate 1. The actual measurement length L varies depending on the length of the conductive substrate and the like, but a guideline is, for example, about 5 mm.

As in the case of FIG. 2, the measurement is carried out at four points on the cross section of the cylindrical conductive substrate at right angles to each other, and in the middle,
That is, the measurement was carried out at the positions rotated by 30 ° and 60 ° from that point (total of 12 equidistant intervals on the circumference of the substrate). This is averaged to calculate Pmax and D. Note that FIG. 2 is a profile showing the change in film thickness measured as an example. In this figure, pmax is the maximum film thickness at one measurement point, and d is the distance in the axial direction of the substrate from the point of pmax until the coating film disappears and the substrate surface is exposed. These average values become the values of Pmax and D. The point where the coating film disappeared was the point where the thickness of the coating film was actually 0.1 μm or less.

Further, the other drum end is also measured and calculated. In the present invention, the values at both ends must individually satisfy the requirements of the present invention.

The measuring device used for the above continuous film thickness measurement was a film thickness measuring device Surfcom (manufactured by Kosaka Laboratory), and the measurement mode was a sectional curve.

In practice, it is easy to provide a coating layer on the surface of a drum-shaped conductive substrate, and to completely remove the coating layer at both ends of the drum to expose the surface of the conductive substrate. is not. At present, a method of rubbing and removing using a brush or tape impregnated with a solvent has been developed. However, although all of these are excellent methods, it has been found that there is a problem even in that case.

That is, even if the coating layer is removed by the above method, the end portion thereof has a shape as shown in the enlarged schematic sectional view of FIG.

In FIG. 2, a coating layer 2 such as a photosensitive layer is coated on the surface of a conductive substrate 1. Pmax is the average of the maximum film thicknesses outside the image forming area (sometimes abbreviated as the image area), and P is the average film thickness in the center of the drum. Further, D represents the average distance from the position of Pmax to the region where the coating layer is completely peeled off and the surface of the conductive substrate is exposed (in the present invention, in the case of unit display, all are expressed in μm). is doing).

As shown in FIG. 2, when the surface of the photosensitive drum is viewed microscopically, the film thickness of the photosensitive layer in the central portion of the drum shows a stable value and is usually set within a range of 15 to 50 μm. It has a film thickness. However, the film thickness becomes unstable when approaching the portions where the coating layer on both ends is removed. For example, as shown in this figure, the film thickness rises slightly and becomes thicker, and then gradually becomes thinner.

The shape of the portion where the photosensitive layer is removed by rubbing has various microscopic sectional shapes as shown in FIG. 3, and various shapes are shown for reference. Figure 3 (a)
Shows the same system shape as described in FIG. 2, but (b)
Is a Pmax thicker than P after passing through a portion having a lower film thickness than the constant film thickness portion before reaching the position of Pmax from the constant film thickness portion.
The shape of which the film thickness gradually decreases after becoming
In (c), although the film thickness does not decrease at a constant rate,
The end portion of the photosensitive layer does not have a portion particularly thicker than P, the thickness gradually decreases, and the surface of the conductive substrate is finally exposed.

Although it is unclear as to what kind of rubbing removal conditions can be applied, it has been found that the change in shape of this portion is too large. This is because, as shown in the conceptual cross-sectional view of FIG. 4, the toner is accumulated or the coagulated substance is adhered to this portion, and the coating layer is peeled from this portion, causing various failures. That is, the adhesion of the toner T is observed at the end of the coating layer 2, and it is clear that the larger the value of Pmax and the larger the value of Pmax / D, the easier it is to do this.

The reason for this will be described in the case of cleaning, which can be well understood by considering the cleaning range as shown in FIG.

The photoconductor drum 3 has a coating layer 2 coated on a conductive substrate 1. Of these, the one used for image formation is the range in which the magnetic brush of the developing device abuts or faces (image formation). Area B. Further, the cleaning is performed on the region F in contact with the cleaning member (in many cases, the cleaning blade). The region B is in a region where there is no influence of the film thickness variation due to the removal of the coating layer, and the region F includes a region where the photosensitive layer is completely peeled off. Naturally, the photosensitive layer on the photosensitive drum is coated to a position wider than the region B and narrower than the region F, but as described above, the end portion is affected by the removal of the coating layer. Therefore, the value of the film thickness is unstable due to local fluctuations. The more the local fluctuation of the end portion is, the more toner is attached, or the portion is easily peeled off due to the stress received from the cleaning blade or the like, and thus the problem is likely to occur. Incidentally, C is the central portion of the electrophotographic photosensitive drum.

This situation can be said to be exactly the same for the charging roller and the charging brush in the charging process. This can be easily understood by replacing the cleaning blade with a charging roller or a charging brush.

However, it has been found that when the contact charging type constitution as in the present invention is adopted, even if the charging roller, the charging brush or the like does not necessarily reach the end portion of the photosensitive layer, a trouble such as film peeling is likely to occur. The reason for this is not clear, but this phenomenon is particularly severe when charged by using an AC / DC superimposed power source, and it becomes remarkable when image formation is performed intermittently. It is considered that the film peeling is caused when a certain kind of impact is repeatedly applied to the photoreceptor. It has been found that such a problem can be obviously alleviated by adopting the configuration of the present invention.

Usually, Pmax is 10 to 60 μm, preferably 15 to 50 μm, and P is 15 to 35 μm, preferably 15 to 30 μm. In the present invention, (Pmax
/ D) × 100 must be suppressed to 2 to 50%, preferably 3 to 40%. When Pmax exceeds 60 μm, the powder may be easily peeled off, and the powder of the coating layer is likely to adhere to the image area to easily cause image defects. Also, (Pmax /
When D) × 100 is less than 2%, it is difficult to process and is difficult to manufacture. When (Pmax / D) × 100 is more than 50%, the toner is contaminated and the adhesiveness at the end of the coating layer is deteriorated. .

There is no particular limitation on the method of removing the coating layer so as to be within the above range. However, it is the tape-based method or the brush-based removal method that can stably remove the coating layer of the photosensitive drum within the above range. These methods will be described below.

2. Removal of photosensitive layer As means for controlling the end shape within the specified range of the present invention, tape material, tape application method, tape end shape, brush material, solvent composition, removal time, removal film thickness, coating There is a method of controlling the swelling state before removing the film. Among these, control by the swelling state of the coating layer before removal, how to apply the tape, brush material, and solvent type is relatively easy to achieve.

The solvent used for removal in the present invention varies depending on the type of the coating layer. For example, tetrahydrofuran, methanol, chloroform, methylene chloride, MEK (methyl ethyl ketone), ether such as acetone, alcohol, chlorine There are system solvents, ketone systems and mixed solvents thereof.

A preferred mode for carrying out the removal of the coating layer will be described below with reference to the drawings. (1) Removal Method Using Wiping Tape FIG. 6 shows a schematic view when the wiping tape is set on the photoconductor drum with an inclination angle θ larger than 0 degree.

In FIG. 6, 31 is a wiping tape, 3 is a photosensitive drum, 38 is a former winding roll, 39 is a winding roll, and θ is an inclination angle.

The wiping tape and the end of the photosensitive drum are brought into contact with each other, and the running direction of the wiping tape is inclined at an inclination angle θ larger than 0 degree with respect to the plane perpendicular to the longitudinal direction of the photosensitive drum 3 as shown in FIG. By doing so, the number of contact points between the wiping tape and the cross-section of the coating layer can be reduced, and the once-dissolved coating layer piece can be wiped off so as not to solidify at the end portion, so that burr does not occur at the end portion of the coating layer. Can be smooth. By smoothing the edges, there is no risk of film peeling from the edges or scratches on the edge of the cleaning blade.

<Wiping Tape> The material for the wiping tape can be used without any particular limitation as long as it can be impregnated with the solvent used, is not attacked by the solvent used, and can withstand the tension during wiping. Specifically, polyamide fibers such as 6 nylon fibers and 66 nylon fibers, polyester fibers such as polyethylene terephthalate fibers and polybutylene terephthalate fibers, acrylic fibers, vinylon fibers, vinylidene fibers, polyurethane fibers, fluorine fibers, and aromatic fibers. Synthetic fibers such as polyolefin fibers such as polyamide fibers, polyethylene fibers and polypropylene fibers,
Regenerated fibers such as rayon fibers, semi-synthetic fibers such as acetate fibers, inorganic fibers such as carbon fibers, vegetable fibers such as cotton fibers and hemp fibers, and animal fibers such as wool can be used.

<< Impregnating Solvent >> The impregnating solvent used by impregnating the wiping tape varies depending on the type of the coating layer, but is not particularly limited as long as it can be dissolved or swollen to remove the coating layer, and the above-mentioned solvents are used. Can be done.

The wiping method is a method in which the wiping tape is impregnated with a solvent that dissolves or swells the coating layer, and the wiping tape is brought into contact with the coating layer of the rotating photosensitive drum to wipe the coating layer.

The moving direction of the wiping tape is not particularly limited, but it is preferable that the wiping tape is wiped in a short time by setting it in the direction opposite to the rotating direction of the photosensitive drum.

FIG. 7 is a schematic view showing an example of a method of bringing the wiping tape into contact with the photosensitive drum.

As a concrete method of bringing the wiping tape into contact with the end portion of the coating layer of the photosensitive drum, FIG.
(B) and (c) can be mentioned.

In FIG. 7A, the wiping tape 31 is applied with a constant tension between the original winding roll 38 and the winding roll 39, and the photosensitive drum 3 is pressed against the pressing roller 32.
It is a method of contacting. In order to incline the running direction of the wiping tape 31 at an inclination angle θ larger than 0 degrees, it can be arbitrarily set by shifting the setting positions of the original winding roll 38 and the winding roll 39 as shown in FIG.

In FIG. 7B, the pressing roller 32 shown in FIG.
It is a method of contacting with.

FIG. 7C shows a method in which the take-up roll 39 shown in FIG. 7A is replaced with a nip drive roller 35 and the wipe tape 31 which has been wiped is collected in a collecting container 37. Since the wiped tape 31 that has been wiped off is impregnated with the solvent, it is preferable to collect the wiped tape 31 in the collection container 37 because the solvent is not likely to be vaporized into the room.

(2) Stripping Method Using Brush FIG. 8 is a sectional view of a coating layer removing device using a brush. Reference numeral 3 in the figure denotes a photosensitive drum having a coating layer formed on the surface thereof. The photosensitive drum is gripped by the transport means 47 so as to be movable up and down, and is brought into contact with a sliding member 55 provided on a coating layer removing base (coating layer removing means) 54 of the coating layer removing device. The coating layer removing base 54 is also provided with a sponge-shaped base holding member 541, and the base a is supported at its lower end by a base holding base and a rubbing member. The coating layer removing table 54 is designed to be rotatable by driving a motor or the like. The photoconductor drum 3 is installed on the coating layer removing table 54 by the transporting means 47 having a gripping means (O-ring chuck, air picker chuck, etc.) for gripping the inside of the base body, and the lower end of the photoconductor drum 3 is rubbed by the sliding member 55. (FIG. 8a). At this time, the coating layer removal table 54 is in a state of being projected from the liquid surface of the solvent tank 51 which is a cleaning means. With the residual solvent in the end coating layer of the photosensitive drum being 60% by mass or less, the coating layer removing table 54 rotates, and the coating layer at the lower end is wiped off by the rubbing member 55 with the rotation. After this wiping is completed, the photosensitive drum is lifted by the conveying means 47 (also serving as the separating means) and separated from the coating layer removing table 54. Thereafter, the coating layer removing table 54 is a cylinder (moving means of the coating layer removing means) 5 that enables the coating layer removing table 54 to move up and down.
By the rotation of 42, it is immersed in the solvent 51E of the solvent tank 51 which is a cleaning means (FIG. 8 (b)), and in the solvent tank,
By combining the ultrasonic cleaning machine and the vertical movement of the coating layer removal table by a cylinder, and the rotational movement, the entire coating layer removal table including the rubbing member is cleaned. After that, by rotating the cylinder 542 again, the cylinder 542 is lifted above the liquid surface of the solvent tank 51 to prepare for removal of the next coating layer. Further, it is preferable to install an ultrasonic transducer U in the solvent tank to enhance the cleaning efficiency of the coating layer removing means. When two or more coating layers are removed at the same time as shown in FIG. 8, a partition plate 59 is provided between the coating layer removing means so as to bounce off the coating layers of the respective photosensitive drums 3 during peeling. It is preferable to prevent the occurrence of defects.

As the material of the rubbing member, there are brush, sponge, cloth, polymer fiber cloth and the like, and the brush is preferable.

Suitable materials for the brush are nylon, polyethylene, polypropylene, polyester and the like. The size of one hole for planting the brush on the coating layer removal table 54 is about 0.5 to 2 mm, and the distance between the holes is about 1 to 3 mm. The entire width of the brush is preferably used so as to correspond to the width of the coating layer to be removed.

In the present invention, the solvent-impregnated rubbing member need only carry the solvent even if the material of the rubbing member is not impregnated with the solvent. The impregnated amount of the rubbing member is preferably 105 to 200 parts by mass when the impregnated amount of the rubbing member during drying is 100 parts by mass.

FIG. 9 is a vertical sectional view of the contact state of the photosensitive drum 3 and the sliding friction member 55. The photoconductor drum 3 is in contact with the brush 551 of the rubbing member.

FIGS. 10A, 10B, and 10C show one form of the rubbing member 55. FIG. 11 is an overall configuration diagram of the coating layer removing device 50.

The coating layer removing device 50 includes a solvent tank 51, a solvent overflow chamber 52, a replenishment tank 53, a coating layer removing table 54, a rubbing member 55, a solvent circulation pipe 56, and a pump 5.
7, a filter 58, a conveying means 47, and the like.

A rubbing member 55 and a substrate holding member 541 are attached to the coating layer removing base 54. When the rubbing member is rotated by the rotation of the coating layer removing base 54 at the same time as fixing the base body a, the lower end of the photoreceptor is The applied layer is wiped off and removed. Incidentally, as shown in FIG.
Is designed to be movable in and out of the solvent tank 51 by rotating the cylinder 542 together with the rubbing member 55 and the like.

Further, the solvent in the solvent tank is the replenishment tank 5
The coating layer components are removed by providing a filter in the middle of the normal circulation pipe so that the solvent can sufficiently wash the coating layer removing means.

3. Structure of Photoreceptor (1) Conductive Substrate (Conductive Support) A cylindrical conductive support is used as the conductive substrate used in the photoreceptor of the present invention. The cylindrical conductive support means a cylindrical support that needs to be capable of forming an image endlessly by being rotated, and has a straightness of 0.1 mm.
In the following, a conductive support having a deflection of 0.1 mm or less is preferable. If the straightness and the shake range are exceeded, good image formation becomes difficult.

As the conductive material, a metal drum of aluminum, nickel or the like, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. It is preferable that the conductive support has a specific resistance of 10 ³ Ωcm or less at room temperature.

(2) Intermediate Layer The intermediate layer (UCL) used in the photoconductor of the present invention is a layer for improving the adhesion between the electroconductive substrate and the photoconductive layer or preventing charge injection from the support. The material for the intermediate layer, which is provided between the support and the photosensitive layer, is a polyamide resin, a vinyl chloride resin, a vinyl acetate resin, or a copolymer containing two or more of the repeating units of these resins. Resins may be mentioned. Among these resins, a polyamide resin is preferable as a resin that can reduce the increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is preferably 0.01 to 2.0 μm.

The intermediate layer most preferably used in the present invention is an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent or a titanium coupling agent. The thickness of the intermediate layer using the curable metal resin is preferably 0.01 to 2.0 μm.

Another preferable intermediate layer is a layer containing titanium oxide and a binder resin, in which titanium oxide is dispersed and applied in a binder resin solution. The thickness of the intermediate layer using titanium oxide is preferably 0.1 to 15 μm.

The preferred photosensitive layer constitution of the organic photoreceptor of the present invention will be described below. (3) Photosensitive Layer The photosensitive layer structure of the photoconductor of the present invention may be a single-layer photosensitive layer structure in which one layer has a charge generating function and a charge transporting function on the undercoat layer, but is more preferable. It is preferable that the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL). By adopting a constitution in which the functions are separated, the increase in residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negative charging photoreceptor, it is preferable that a charge generation layer (CGL) is formed on the undercoat layer and a charge transport layer (CTL) is formed on the charge generation layer. In the case of the photoconductor for positive charging, the order of the layers is the reverse of that of the photoconductor for negative charging. The most preferable photosensitive layer structure of the present invention is a negative charging photosensitive member structure having the function separation structure.

The structure of the photosensitive layer of the function-separated negative charging photosensitive member will be described below. << Charge Generation Layer >> The charge generation layer of the present invention contains a charge generation substance and a binder resin, and is formed by dispersing and coating the charge generation substance in a binder resin solution.

As the charge generating substance, a known phthalocyanine compound can be used. Preferred are titanyl phthalocyanine compounds and hydroxygallium phthalocyanine compounds. Furthermore, Y type of titanyl phthalocyanine,
Cu-Kα characteristic X-rays (wavelength 1.54) such as A type (β type)
A titanyl phthalocyanine compound, which is characterized by a main peak of Bragg angle 2θ with respect to Å), is preferable. Regarding these oxytitanyl phthalocyanines, JP-A-10-06910
No. 7 publication. Further, these charge generating substances may be used alone or in combination of two or more kinds such as Y type and A type, or may be used by mixing with polycyclic quinone such as perylene pigment.

As the binder resin for the charge generation layer, known resins can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, Epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin,
Melamine resin, and copolymer resins containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin) and poly-vinyl Examples thereof include carbazole resin, but are not limited thereto.

The charge generating layer is formed by dispersing a charge generating substance in a solution in which a binder resin is dissolved in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a constant film thickness by the coating machine. Then, it is preferable that the coating layer is dried to be manufactured.

Solvents for dissolving and applying the binder resin used in the charge generation layer include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol. , Propanol, butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1,4-dioxane, 1,3
-Dioxolane, pyridine, diethylamine and the like, but not limited thereto.

As the means for dispersing the charge generating substance, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer or the like can be used, but it is not limited to these.

Examples of coating machines for forming the charge generation layer include, but are not limited to, dip coating machines and ring coaters.

The mixing ratio of the charge generating substance to the binder resin is preferably 1 to 600 parts by weight of the charge generating substance (hereinafter referred to as parts by weight), and more preferably 50 to 500 parts by weight with respect to 100 parts by weight of the binder resin. . The thickness of the charge generation layer varies depending on the characteristics of the charge generation substance, the characteristics of the binder resin, the mixing ratio, etc., but is preferably 0.01 to 5 μm.

<Charge Transport Layer> The charge transport layer of the present invention contains a charge transport substance and a binder resin, and is formed by dissolving and coating the charge transport substance in a binder resin solution.

The charge-transporting substance is described in Japanese Patent Application No. 2000-3609.
In addition to the charge-transporting substances represented by the general formula in the specification of No. 98, for example, carbazole derivative, oxazole derivative, oxadiazole derivative, thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative,
Bisimidazolidine derivative, styryl compound, hydrazone compound, pyrazoline compound, oxazolone derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, triarylamine derivative, phenylenediamine derivative, stilbene derivative, benzidine Derivatives, poly-N-vinylcarbazole, poly-1-
Vinylpyrene and poly-9-vinylanthracene
You may use it in mixture of 2 or more types.

As the binder resin for the charge transport layer, known resins can be used, such as polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylate ester resin and styrene. -Methacrylic acid ester copolymer resin and the like can be mentioned, but polycarbonate is preferable. Furthermore, BPA and BP of polycarbonate
Z, dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of cracking, abrasion resistance and charging characteristics.

The charge transport layer can be formed by dissolving a binder resin and a charge transport substance to prepare a coating solution, coating the coating solution with a coating machine to a constant film thickness, and drying the coating layer. preferable.

As the solvent for dissolving the binder resin and the charge transport substance, for example, toluene, xylene,
Methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1,4-dioxane, 1,
Examples thereof include, but are not limited to, 3-dioxolane, pyridine and diethylamine.

The mixing ratio of the charge transporting material to the binder resin is preferably 10 to 500 parts by weight of charge transporting material (hereinafter referred to as “parts by weight”) per 100 parts by weight of the binder resin.
It is more preferably 20 to 100 parts.

The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio, etc., but is preferably 10 to 100 μm, more preferably 15 μm.
Is about 40 μm.

Further, in the charge transport layer, an antioxidant (AO
Agent), an electron-accepting substance (EA agent), a stabilizer and the like may be added. Regarding the AO agent, Japanese Patent Application No. 11-200135
Nos. And EA agents are preferably those described in JP-A Nos. 50-137543 and 58-76483.

(4) Protective Layer In order to improve durability, a protective layer may be provided on the charge transport layer. JP-A-9-190004, JP-A-10-0
The protective layer using a siloxane-based resin described in JP-A No. 95787 and JP-A No. 2000-171990 is preferable because it improves abrasion resistance. The most preferable layer constitution of the organic photoreceptor of the present invention has been exemplified above, but the layer constitution other than the above may be adopted in the present invention.

Next, an image forming apparatus using the photoconductor drum manufactured by the method for manufacturing the photoconductor drum of the present invention will be described.

[2] Charging Step and Charging Member In the charging step of the present invention, various charging members such as a magnetic brush type, a charging roller type and a blade type can be used. Among them, as the charging member, a charging roller type,
Alternatively, the magnetic brush method is most preferably used in the present invention. That is, a charging roller or a magnetic brush, which can easily obtain uniform charging, is preferable. Hereinafter, the charging process and charging means of the charging roller system and the magnetic brush system will be described.

In the present invention, a charging roller or a magnetic brush composed of a conductive elastic charging member is brought into contact with a photosensitive member (image carrier), and a voltage is applied to the charging roller to charge the photosensitive member. Can be done.

1. Charging Roller Method (1) Charging Roller Configuration, Manufacturing Method, etc. Such a charging roller method may be either a DC charging method for applying a DC voltage to the roller or an induction charging method for applying an AC voltage to the roller.

Frequency f of voltage applied by the induction charging method
Any one can be used, but in order to prevent strobing, that is, a striped pattern, an appropriate frequency can be selected according to the relative speed between the conductive elastic roller and the photosensitive member. The relative speed can be determined by the size of the contact area between the conductive elastic roller and the photosensitive member.

The conductive elastic roller has a cored bar covered with a layer made of a conductive elastic member (also simply referred to as a conductive elastic layer or a conductive rubber layer).

The rubber composition that can be used for the conductive rubber layer includes polynorbornene rubber and ethylene-
Examples thereof include propylene rubber, chloroprene rubber, acrylonitrile rubber, silicone rubber and the like. These rubbers can be used alone or as a mixed rubber of two or more kinds.

In order to impart conductivity, these rubber compositions are mixed with a conductivity-imparting agent and used. Examples of suitable conductivity-imparting agents include publicly known carbon black (furnace-based carbon black or ketjen black) and metal powder such as tin oxide. The conductivity-imparting agent is used in an amount of 5 to 50 parts by mass based on the total amount of the rubber composition.

In addition to the rubber base material, the foaming agent, and the conductivity-imparting agent, the rubber composition may be blended with a rubber chemical and a rubber additive, if necessary, to give a conductive foamed rubber composition.
Chemicals for rubber, as rubber additives, vulcanizing agents such as sulfur and peroxide, vulcanization accelerators such as zinc white, stearic acid, sulfenamide-based, thirium-based, thiazole-based,
It is possible to use vulcanization accelerators such as granidine-based, amine-based, phenol-based, sulfur-based and phosphorus-based antioxidants, or antioxidants, ultraviolet absorbers, ozone deterioration inhibitors, tackifiers, etc. Further, various reinforcing agents, friction coefficient adjusting agents, and inorganic fillers such as silica, talc, and clay may be arbitrarily selected and used. These conductive rubber layers are 10 ³ to 1
It preferably has a DC volume resistivity in the range of 0 ⁷ Ω · cm.

Further, a releasable coating layer may be provided on the outer side of these conductive elastic layers for the purpose of preventing the toner remaining on the surface of the photoreceptor from adhering to the charging member. Preventing oil from seeping out from the coating layer or elastic layer, canceling resistance unevenness of the elastic layer, achieving uniform resistance, protecting the surface of the charging roller, adjusting hardness of the charging roller, etc. Fulfills the function of. The coating layer may be any layer as long as it satisfies the above physical properties, and may be a single layer or a plurality of layers. Examples of the material include resins such as hydrin rubber, urethane rubber, nylon, polyvinylidene fluoride, and polyvinylidene chloride.

The thickness of the coating layer is 100 to 1000 μm.
And the resistance value is 10 ⁵ to 10 ⁹ Ω · cm
Is preferred. In addition, it is preferable that the resistance value increases as it approaches the surface layer. As a method of adjusting the resistance, it is possible to include a conductive material such as carbon black, metal and metal oxide in the coating layer.

In order to adjust the surface roughness Rz of the charging roller of the present invention, it is preferable that the surface layer (conductive elastic layer or coating layer) of the charging roller contains powder. The particles used in the present invention may be either an inorganic substance or an organic substance, but in the case of the inorganic substance, silica powder is particularly preferable. Examples of organic substances include urethane resin particles, nylon particles, silicone rubber particles, and epoxy resin particles.
These particles may be used alone or in admixture of two or more. Suitable particles have a surface layer surface roughness Rz of 0.05 to 1
A substance that can be adjusted to the range of 0.0 μm may be selected, but if the particle size of the particles is in the range of 1 to 20 μm, the desired surface roughness range can be easily achieved.

The compounding ratio of the powder in the surface layer was 100
It is preferable to mix and disperse in a proportion of 5 to 20 parts by mass with respect to parts by mass.

The charging roller of the present invention can be manufactured, for example, as follows. That is, first, a metal rotary shaft (core metal) is placed in a molding die having a cylindrical molding space, the conductive elastic layer forming material is filled in the molding die, and vulcanization is performed to form the outer circumference of the rotation shaft. A conductive elastic layer is formed on the surface. Then, the rotary shaft on which the conductive elastic layer is formed is taken out from the mold. On the other hand, a material such as urethane resin is mixed with granules, a conductivity imparting agent and other additives, and the mixture is mixed and stirred using a ball mill or the like to prepare a surface layer forming material mixture. Then, this mixture is applied by a dip method, a roll coating method, a spray coating method or the like on the surface of the rotating shaft on which the conductive elastic layer is formed, dried, and cured by heating to form a two-layer structure. A charging roller can be manufactured.

The surface roughness Rz of the outermost surface layer of the charging roller thus obtained is 0.05-1.
It is formed to 0.0 μm.

(2) Application Example of Charging Roller to Image Forming Apparatus FIG. 12 is a block diagram showing an example of an image forming apparatus to which a charging roller is applied. This image forming apparatus is for carrying out the present invention, and charges a charging roller by contacting it with a photosensitive drum for forming an electrostatic latent image, and a transfer pole for transferring toner to a transfer paper. In this embodiment, a transfer roller is used, and the transfer roller is brought into contact with the photosensitive drum directly or with a transfer paper sandwiched therebetween to avoid generation of ozone.

In FIG. 12A, an electrostatic latent image is formed on the photosensitive drum 3 charged by the charging roller 4. Then, this electrostatic latent image is visualized as a toner image by a developing sleeve which is a developer carrying member of the developing device 16 arranged in the vicinity of the photosensitive drum 3. Then, after the charge of the photoconductor drum 3 is removed by the charge removal lamp 5 before transfer, the toner image is transferred by the transfer roller 6 to the transfer material (transfer paper) 18 transferred from the paper feed cassette by the transfer roller 8. An electric charge having a polarity opposite to that of the toner is applied, and the toner is transferred to the transfer material 18 by the electrostatic force of the electric charge having the opposite polarity. The transfer material 18 after the toner transfer is the photosensitive drum 3
After being separated from the sheet, it is sent to the fixing device by the conveyor belt 7, and the toner image is fixed on the transfer material 18 by the heating roller and the pressing roller.

A bias voltage composed of DC and AC components is applied from the power source 9 (10) to the charging roller 4 (and the transfer roller 6), and the toner and the toner on the photosensitive drum 3 are charged while the ozone generation amount is extremely small. The image is transferred to the transfer paper 18. The bias voltage is usually ± 500 to
DC bias of 1000V and 100Hz superimposed on it
-10 KHz, AC bias of 200-3500 Vp-p.

The charging roller 4 and the transfer roller 6 are driven or forcedly rotated while being pressed against the photosensitive drum 3.

The pressure contact with the photosensitive drum 3 is 0.1 to 10.
The rotation of the roller is set to 1.0 N / cm and is set to 1 to 8 times the peripheral speed of the photosensitive drum 3.

As shown in FIG. 12B, the charging roller 4 (and the transfer roller 6) has a cored bar 20 and conductive elastic members such as chloroprene rubber, urethane rubber, and silicone rubber provided around the cored bar 20. Rubber layer or sponge layer 21 thereof, and preferably 0.01 to 1 μm in the outermost layer.
The protective layer 22 is composed of a m-thick releasable fluorine resin or silicone resin layer.

After the transfer, the photosensitive drum 3 is cleaned by pressing the cleaning blade 12 of the cleaning device 11 and is ready for the next image formation.

In the electrophotographic image forming apparatus, a photosensitive member and any one of constituent elements such as a charging roller, a developing device, a transfer roller, and a cleaning device are integrally combined as a process cartridge, and this unit is the main body of the apparatus. Alternatively, it may be detachably configured. Further, at least one of an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge, which is a detachable (removable) single unit in the device main body. You may form so that it may be loaded using a guide means such as a rail of the main body.

In FIG. 12, a roller charger is used for both the charger and the transfer pole, but in the present invention, the essential constituent requirement of the present invention is to use a charging roller for the charger. A transfer means other than the transfer roller may be used for the transfer pole.

2. Magnetic Brush Method (1) Configuration of Magnetic Brush Charging Device Next, the magnetic particles forming the magnetic brush for charging will be described.

FIG. 13 is a block diagram of a contact type magnetic brush charger, and FIG. 14 is a diagram showing a relationship between an AC bias voltage and a charging potential by the charger of FIG.

Generally, when the volume average particle diameter of the magnetic particles forming the magnetic brush for charging is large, (a) the state of the ears of the magnetic brush formed on the carrier for carrying magnetic particles for charging (carrier) is rough. Even when charging is performed while applying vibration due to an electric field, unevenness is likely to appear on the magnetic brush, which causes a problem of uneven charging. In order to solve this problem, the volume average particle diameter of magnetic particles should be reduced.
The effect starts to appear when the thickness is 00 μm or less, and particularly when the thickness is 150 μm or less, the problem associated with the coarseness of the ears of the magnetic brush is substantially eliminated. However, if the particles are too fine, they tend to adhere to the surface of the photoconductor drum 3 at the time of charging, or easily scatter. These phenomena are also related to the strength of the magnetic field acting on the particles and the strength of the magnetization of the particles due to the strength of the magnetic fields, but generally, the volume average particle diameter of the particles becomes prominent at 20 μm or less.

From the above, the magnetic particles have a volume average particle diameter of 20 to 200 μm, and 30% by number or less of magnetic particles having a particle diameter of 1/2 times or less of the number average particle diameter of the magnetic particles. It is preferable that The strength of magnetization is 3.
Those of 7 × 10 ^{−2 to} 13 × 10 ⁻² ewb · m / g are preferably used.

Such magnetic particles are the same as the magnetic carrier particles of the conventional two-component developer as a magnetic material,
Ferromagnetism such as metals such as iron, chromium, nickel and cobalt, or their compounds and alloys such as ferric tetroxide, γ-ferric oxide, chromium dioxide, manganese oxide, ferrite and manganese-copper alloys. Particles of the body, or the surface of the magnetic particles are coated with a resin such as styrene resin, vinyl resin, ethylene resin, rosin-modified resin, acrylic resin, polyamide resin, epoxy resin, polyester resin, or Particles obtained by making a resin containing magnetic fine particles dispersed therein can be obtained by selecting the particle size by a conventionally known average particle size selecting means.

It should be noted that forming spherical magnetic particles
The particle layer formed on the carrier is made uniform, and a high bias voltage can be uniformly applied to the carrier. That is, the fact that the magnetic particles are spherical means that (1) generally, the magnetic particles are easily magnetized and adsorbed in the long-axis direction, but due to the spherical shape, the directionality is lost, so that the magnetic particle layer is uniformly formed. , (2) To prevent the occurrence of locally low resistance regions and unevenness of layer thickness. (2) With the increase in the resistance of magnetic particles, the edge part as seen in conventional particles is eliminated, and the electric field to the edge part is eliminated. Concentration does not occur, and as a result, even if a high bias voltage is applied to the carrier for carrying the charging magnetic particles, there is an effect that the surface of the photosensitive drum 3 is uniformly discharged and charging unevenness does not occur.

As the spherical particles having the above effects, conductive particles are preferably formed so that the magnetic particles have a resistivity of 10 ⁵ to 10 ¹⁰ Ω · cm. This resistivity is 9.8 N / on the packed particles after the particles are placed in a container having a cross-sectional area of 0.50 cm ² and tapped.
Apply a load of cm ² and 1000 between the load and the bottom electrode.
It is a value obtained by reading the current value when a voltage that generates an electric field of V / cm is applied. If this resistivity is low, charges are injected into the magnetic particles when a bias voltage is applied to the carrier. As a result, magnetic particles are likely to adhere to the surface of the photosensitive drum 3, or dielectric breakdown of the photosensitive drum 3 due to the bias voltage is likely to occur. If the resistivity is high, charge injection is not performed and charging is not performed.

Further, the contact type magnetic brush charger 120
It is desirable that the magnetic particles used in (1) have a small specific gravity and have an appropriate maximum magnetization so that the magnetic brush constituted by them can move lightly due to an oscillating electric field, and that external scattering does not occur. Specifically, those having a true specific gravity of 6 or less and a maximum magnetization of 3.7 × 10 ^{−2 to} 13 × 10 ⁻² ewb · m / g, particularly 5.0 × 10 ⁻² to 80 × 10 ⁻² ewb · m /
It has been found that good results are obtained with g.

In summary, the magnetic particles are spherical so that at least the ratio of the major axis to the minor axis is 3 times or less, there are no protrusions such as needles and edges, and the resistivity is It is preferably in the range of 10 ⁵ to 10 ¹⁰ Ω · cm. Then, such spherical magnetic particles should be selected as spherical as possible for the magnetic particles, and in the particles of the magnetic material fine particle dispersion system, the fine particles of the magnetic material should be used as much as possible, and the spheroidizing treatment should be performed after the formation of the dispersed resin particles. It is manufactured by applying or by forming dispersed resin particles by a spray drying method.

According to FIG. 13 or FIG. 14, the magnetic brush charger 120 as a charger faces the rotating photoconductor drum 3 and is in the same direction (countercharge) in the vicinity (charging unit T) of the photoconductor drum 3. A cylindrical charging sleeve 120a made of, for example, an aluminum material or a stainless material, serving as a charging magnetic particle carrier rotated in the clockwise direction, and the charging sleeve 12.
Magnet body 121 consisting of N and S poles provided inside 0a
And a magnetic brush composed of magnetic particles formed on the outer peripheral surface of the charging sleeve 120a by the magnet body 121 to charge the photosensitive drum 3, and a magnetic brush on the charging sleeve 120a at the NN magnetic pole portion of the magnet body 121. A scraper 123 for scraping off the magnetic particles, an agitating screw 124 for agitating the magnetic particles in the magnetic brush charger 120, or an agitating screw 124 for discharging used magnetic particles by overflowing them from the outlet 125 of the magnetic brush charger 120, and a magnetic brush. It is constituted by the spike control plate 126. The charging sleeve 120a is rotatable with respect to the magnet body 121, and is 0.1 to 1.0 times in the same direction (counterclockwise direction) as the moving direction of the photosensitive drum 3 at a position facing the photosensitive drum 3. Is preferably rotated at a peripheral speed of. A conductive carrier that can apply a charging bias voltage is used as the charging sleeve 120a, and in particular, the magnet body 1 having a plurality of magnetic poles inside the conductive charging sleeve 120a having a particle layer formed on the surface thereof.
A structure having 21 is preferably used. In such a carrier, the conductive charging sleeve 120a is rotated by the relative rotation with the magnet body 121.
Since the magnetic particle layer formed on the surface of the will move in a wavy manner, new magnetic particles will be supplied one after another,
Even if the magnetic particle layer on the surface of the charging sleeve 120a has some unevenness in the layer thickness, the effect is sufficiently covered by the wavy undulation so as not to cause a practical problem. It is preferable that the surface of the charging sleeve 120a has an average roughness of 5.0 to 30 μm for stable and uniform transfer of magnetic particles. If the surface is smooth, the transfer cannot be performed sufficiently, and if it is too rough, the surface is convex. Overcurrent flows from the part, and uneven charging is likely to occur in either case. Sandblasting is preferably used to achieve the above surface roughness. In addition, the charging sleeve 12
The outer diameter of 0a is preferably 5.0 to 20 mm. This ensures the contact area required for charging. If the contact area is unnecessarily large, the charging current will be excessive, and if it is small, uneven charging is likely to occur. Further, when the diameter is small as described above, magnetic particles are easily scattered or adhered to the photoconductor drum 3 due to centrifugal force. Therefore, the linear velocity of the charging sleeve 120a is almost the same as the moving velocity of the photoconductor drum 3, or more than that. Is also preferably slow.

Further, the thickness of the magnetic particle layer formed on the charging sleeve 120a is preferably such that it is sufficiently scraped off by the regulating means to form a uniform layer. If the amount of magnetic particles on the surface of the charging sleeve 120a is too large in the charging region, the magnetic particles are not sufficiently vibrated to cause abrasion of the photoconductor and uneven charging, and an overcurrent tends to flow, resulting in a driving torque of the charging sleeve 120a. Has the drawback of becoming large. On the contrary, if the amount of the magnetic particles existing on the charging sleeve 120a in the charging area is too small, an incomplete portion may be formed in contact with the photosensitive drum 3, and the magnetic particles may adhere to the photosensitive drum 3 or cause uneven charging. become.

The magnetic brush charger 120 as a charger is provided with an alternating current (A) as needed for the direct current (DC) bias E3.
C) A charging bias on which the bias AC3 is superimposed, for example, −100 to −500 V having the same polarity as the toner (negative polarity in this embodiment) as the DC bias E3, and a frequency 1 to 5 kHz and a voltage 300 to 300 as the AC bias AC3. By the charging sleeve 120a to which a charging bias of 500 Vp-p is applied, the peripheral surface of the photoconductor drum 3 is contacted and rubbed, and the photoconductor drum 3 is charged. Since an oscillating electric field is formed between the charging sleeve 120a and the photosensitive drum 3 by the voltage application of the AC bias AC3, the charge is smoothly injected onto the photosensitive drum via the magnetic brush. Thus, high-speed charging is performed.

Charging sleeve 1 in which the photosensitive drum 3 is charged
The magnetic brush on 20a is N provided on the magnet body 121.
In the −N magnetic pole part, the magnetic brush is stirred by the stirring screw 124 that is dropped from the charging sleeve 120a by the scraper 123 and rotates in the opposite direction (counterclockwise) to the charging sleeve 120a in the vicinity of the charging sleeve 120a. It is formed and conveyed to the charging section T.

As shown in FIG. 14, the relationship between the peak-peak voltage Vp-p of the AC bias AC3 of the charging bias and the charging potential is that the charging potential increases as the peak-peak voltage Vp-p increases, and the charging potential increases. The electric potential is V1 with a constant peak-peak voltage, and the DC bias E of the charging bias.
It saturates at a value almost equal to VS of 3 and peaks further.
There is a characteristic that the charging potential hardly changes even if the peak voltage Vp-p is increased. Although the electric resistance of the magnetic particles varies depending on the environmental conditions, the electric resistance increases as the toner is fused to the surface of the magnetic particles as it is used. Therefore, the characteristic curve is shown on the left side as shown by a solid line in the case of new magnetic particles in the initial stage of use, and on the right side as shown by a dotted line in the case of magnetic particles used for a long time as shown in (b). Will be located in.

In the contact type charger of the image forming apparatus of the present invention, the voltage value of the DC bias E3 corresponding to the charging potential is set to a predetermined value when the mounting power source is turned on or before printing is started, and the peak / peak of the AC bias AC3. Voltage Vp-p
Is applied to a charging bias which is gradually increased from a low value, and the charging potential of the photosensitive drum 3 which changes at that time is measured by an electrometer ES.
Detect by. The detected charging potential is converted into a digital value by the A / D converter, and then the control unit (CP
U). In the control unit, this charging potential is a predetermined value V
The value of Vp-p when the saturation point of S is reached is defined as the proper bias value V1 and the printing operation is performed.

That is, when printing is performed, the AC bias AC3 is gradually increased (swept) from a low value.
The value V1 of Vp-p of the AC bias AC3 is obtained, and the bias signal is output from the control unit. This control signal is D / A
After being converted into an analog value by the converter, it is sent to the AC bias AC3, and the AC bias AC3 outputs the determined peak-to-peak voltage V1. The peak-peak voltage V1 at that time and the specified value V2 to be exchanged due to the deterioration of the magnetic particles stored in the memory are read out and compared with this. Since the resistance of the magnetic particles increases due to the mixing of toner, the proper bias value V1 increases with the use of printing. Along with this, the applied Vp-p increases, and an unchargeable state occurs. Image formation is continued while the measured voltage value is smaller than the specified value V2 indicating that charging is impossible. The charger display is displayed on the operation display. Based on this display, the charging magnetic particle supply bottle 220 is set in the magnetic brush charger 120, and an opening / closing lid (not shown) on the bottom surface of the supply bottle 220 is opened to remove the magnetic particles from the magnetic brush charger 12.
Drop to 0 and supply. In the above description, the electrometer ES was used to measure the potential of the photoconductor drum 3. However, when the AC bias Vp-p was changed by connecting a DC ammeter to the bias power source and the current value reached the saturation point, Vp-p is set as an appropriate bias value V1, and a comparison with a specified value V2 is performed to obtain V1.
The magnetic particles may be supplied when the temperature exceeds.

Further, during maintenance or at regular intervals such as 50,000 prints, the magnetic particles for charging are exchanged. A replacement signal is output through the control unit at regular intervals of every maintenance print stored in the memory or, for example, every 50,000 prints, and the supply of the supply bottle 220 of the magnetic particles for charging preset by the drive of the drive motor (not shown). The roller 221 is rotated, and all the magnetic particles in the supply bottle 220 are dropped into the magnetic brush charger 120 at one time. It is also possible to remove the empty supply bottle 220 after the supply and set a new supply bottle 220 to control the image forming apparatus to the operating state. Further, at a regular time, the control unit displays a supply signal such as a blinking lamp on the operation unit (not shown), sets the supply bottle 220 on the magnetic brush charger 120, and opens an opening / closing lid (not shown) on the bottom surface of the supply bottle 220. Alternatively, the magnetic particles may be supplied.

The dropped magnetic particles are conveyed by the rotating charging sleeve 120a, scraped off the surface of the charging sleeve 120a by the scraper 123, and supplied to the bottom of the magnetic brush charger 120. Along with this, the used magnetic particles housed inside the magnetic brush charger 120 overflow from the outlet 125 by the stirring screw 124 that is rotated counterclockwise, and the common magnetic particle recovery container 300 passes through the duct DB. Will be collected. On this occasion,
The amount of magnetic particles supplied from the supply bottle 220 into the magnetic brush charger 120 once is equal to the magnetic brush charger 120.
20 to 50 mass% with respect to all magnetic particles stored in
Is preferred. If the amount is less than 20% by mass, the amount of newly supplied magnetic particles is too small to have an exchange effect and good charging cannot be performed. If the amount exceeds 50% by mass, new magnetic particles overflow.

As described above, good charging performance is maintained for a long period of time without deteriorating the magnetic particles in the charger.

(2) Application of magnetic brush charger to image forming apparatus FIG. 15 is a sectional view showing an example of an image forming apparatus having a magnetic brush charger of the present invention. In FIG. 15, reference numeral 3 denotes a photosensitive drum (photosensitive member) which is an image bearing member, and is a photosensitive member in which an organic photosensitive layer is coated on a cylindrical substrate, and the resin layer of the present invention is coated on the cylindrical photosensitive substrate. It is driven and rotated clockwise. 1
Reference numeral 52 denotes a magnetic brush charger, which can uniformly charge the peripheral surface of the photosensitive drum 3. Prior to the charging by the charger 152, the peripheral surface of the photoconductor may be neutralized by exposure by the exposure unit 151 using a light emitting diode or the like in order to eliminate the history of the photoconductor in the previous image formation.

Image exposure device 153 after uniform charging of the photoreceptor
Thus, image exposure is performed based on the image signal. The image exposure device 153 in this figure uses a laser diode (not shown) as an exposure light source. The photosensitive drum is scanned by the light whose optical path is bent by the reflecting mirror 532 through the rotating polygon mirror 531, the fθ lens, etc., and an electrostatic latent image is formed.

The electrostatic latent image is then developed by the developing device 16. A developing device 16 containing a developer composed of toner and carrier is provided on the peripheral edge of the photosensitive drum 3, and development is carried out by a developing sleeve containing a magnet and holding the developer and rotating. The developer is composed of, for example, a carrier in which an insulating resin is coated around the above-mentioned ferrite core, a coloring agent such as carbon black having a styrene acrylic resin as a main material, a charge control agent, and the low molecular weight polyolefin of the present invention. The toner is formed by externally adding colored particles such as silica and titanium oxide. The developer is regulated to a layer thickness of 100 to 600 μm on the developing sleeve by a layer forming means (not shown) and conveyed to the developing zone. Then, development is performed. At this time, normally, a DC bias is applied between the photosensitive drum 3 and the developing sleeve, and an AC bias voltage is applied if necessary, and the development is performed. Also,
The developer is developed in a state of being in contact or non-contact with the photoconductor.

After the image formation, the transfer material 18 is fed to the transfer area by the rotation operation of the paper feed roller 157 when the transfer timing is adjusted.

In the transfer area, the transfer roller (transfer device) 6 is pressed against the peripheral surface of the photosensitive drum 3 in synchronism with the transfer timing, and the supplied transfer material 18 is nipped and transferred.

Then, the transfer material 18 is destaticized by a separating brush (separator) 159 which is brought into pressure contact with the transfer roller almost at the same time, is separated by the peripheral surface of the photosensitive drum 3 and is conveyed to the fixing device 160, and is heated by the heat roller. The toner is fused by heating and pressurizing the pressure roller 601 and the pressure roller 602, and then the toner is discharged to the outside of the apparatus via the paper discharge roller 161. The transfer roller 6 and the separation brush 159 are the transfer material 18
After the passage, the toner is withdrawn from the peripheral surface of the photosensitive drum 3 and is prepared for the next toner image formation.

On the other hand, the photosensitive drum 3 after the transfer material 18 is separated is the cleaning blade 1 of the cleaning device 11.
The residual toner is removed / cleaned by the pressure contact of No. 2, and the charge is removed by the exposure unit 151 and charged by the charger 152 again to start the next image forming process.

Reference numeral 70 denotes a detachable (removable) process cartridge in which a photoconductor, a charging device, a transfer device / separator, and a cleaning device are integrated.

The image forming apparatus includes the above-mentioned photoconductor,
The components such as the developing device and the cleaning device may be integrally combined as a process cartridge, and this unit may be detachably (removable / removable) with respect to the apparatus main body. Further, at least one of a charging device, an image exposing device, a developing device, a transfer or separating device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge, and the process cartridge is detachably (removable / removable) unit. It may be configured as one unit and detachable by using a guide means such as a rail of the apparatus main body.

[3] Developer and Developing Method Next, the developer toner and developing conditions used in the present invention will be described.

In the developing method of the present invention, the electrostatic latent image on the image carrier can be developed using either a one-component developer or a two-component developer. The one-component developer comprises a magnetic toner composed of at least a magnetic powder and a binder resin, and these may contain a colorant.

The developing method may be used either in contact or in non-contact. When a non-contact development method is adopted, non-contact regular development or non-contact reversal development can be carried out. The DC developing electric field at that time is 1 × 10 in absolute value.
³ to 1 × 10 ⁵ V / cm, preferably 5 × 10 ³ to 1 × 1
When it is 0 ⁴ V / cm and less than 10 ³ V / cm, the development is insufficient and sufficient image density cannot be obtained, and when it exceeds 10 ⁵ V / cm, the image quality is deteriorated and fogging occurs.

Next, the AC bias is 0.5 to 4 kVp-
p, preferably 1 to 3 kVp-p, and the frequency is 0.1 to 10 kHz, preferably 2 to 8 kHz.

When the AC bias is less than 0.5 kVp-p, the toner adhering to the carrier is not released, the non-contact development becomes insufficient, and the image density becomes insufficient. When the AC bias exceeds 4 kVp-p, the carrier in the developer flies and the carrier adheres to the photoconductor.

Further, the frequency of the AC bias is 0.1 kHz.
If it is less than the above range, the release of the toner from the carrier becomes insufficient, resulting in insufficient development and reduction in image density. On the other hand, when the frequency of the AC bias exceeds 10 kHz, the toner cannot follow the fluctuation of the electric field, resulting in poor development in the arrow and the image density is lowered.

[4] Cleaning Means and Other Components For cleaning, a blade cleaning system using an elastic rubber blade as a member is preferable. As the elastic rubber, urethane rubber, silicone rubber or the like can be used, but urethane rubber is particularly preferable.

In the image exposure, when the image forming apparatus is used as a copying machine or a printer, the photoconductor is irradiated with reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal. This is performed by irradiating the photoconductor with light by scanning the laser beam, driving the LED array, or driving the liquid crystal shutter array.

When used as a printer for a facsimile, the image exposure device performs exposure for printing the received data.

The image forming apparatus of the present invention can be applied to general electrophotographic apparatuses such as copying machines, laser printers, LED printers and liquid crystal shutter printers. It can be widely applied to devices such as light printing, plate making, and facsimile.

[0158]

EXAMPLES Examples using the removing tape of the present invention will be described below, but the embodiments of the present invention are not limited to the following examples.

Example-1 Part 1 Preparation of Photoreceptor 1 The following coating solution was prepared and coated on a cylindrical aluminum substrate obtained by drawing to form a semiconductive layer having a dry film thickness of 15 μm.

<Semiconductive Layer (PCL) Coating Solution> Phenolic resin 160 g Conductive titanium oxide 200 g Methylcellosolve 100 ml Next, the following intermediate layer coating solution was prepared. This coating solution was applied onto the semiconductive layer by a dip coating method to form an intermediate layer having a film thickness of 1.0 μm.

<Intermediate Layer (UCL) Coating Liquid> Polyamide resin (Amilan CM-8000: manufactured by Toray) 60 g Methanol 1600 ml 1-Butanol 400 ml Further, the following composition liquid was prepared and dispersed for 10 hours using a sand mill to generate charges. A layer coating solution was prepared. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.

<Charge Generation Layer (CGL) Composition Liquid> Y-type titanyl phthalocyanine 60 g Silicone resin solution 700 g (KR5240, 15% xylene-butanol solution: Shin-Etsu Chemical Co., Ltd.) 2-butanone 2000 ml Finally, the following coating composition was mixed. Then, it was dissolved to prepare a charge transport layer coating solution. This coating liquid was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a film thickness of 20 μm, to prepare a photoreceptor 1.

<Charge Transport Layer (CTL) Coating Liquid> Charge Transport Material 200 g Bisphenol Z-type Polycarbonate 300 g (Iupilon Z300: Mitsubishi Gas Chemical Co., Inc.) 1,2-Dichloroethane 2000 ml Preparation of Photoreceptor 2 On a cylindrical aluminum substrate, The following intermediate layer coating solution was applied by dip coating and dried at 150 ° C. for 30 minutes to form an intermediate layer having a thickness of 1.0 μm.

<Intermediate Layer (UCL) Coating Liquid> Zirconium chelate compound ZC-540 (manufactured by Matsumoto Pharmaceutical Co., Ltd.) 200 g Silane coupling agent KBM-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) 100 g Methanol 700 ml Ethanol 300 ml Next, the following coating composition And mix using a sand mill 1
Dispersion was carried out for 0 hours to prepare a charge generation layer coating liquid. This coating solution is applied onto the intermediate layer by a dip coating method to give a film thickness of 0.2.
A charge generation layer of μm was formed.

<Charge Generation Layer (CGL) Coating Liquid> Y-type titanyl phthalocyanine 60 g Silicone resin solution 700 g (KR5240, 15% xylene-butanol solution: manufactured by Shin-Etsu Chemical Co., Ltd.) 2-butanone 2000 ml Furthermore, the following coating composition was mixed. , And dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a film thickness of 20 μm, and a photoconductor 2 was produced.

<Charge Transport Layer (CTL) Coating Liquid> Charge Transport Material 200 g Bisphenol Z-type Polycarbonate 300 g (Iupilon Z300: Mitsubishi Gas Chemical Co., Inc.) 1,2-Dichloroethane 2000 ml Preparation of Photoreceptor 3 The following coating composition was mixed. Then, the protective layer coating solution was prepared by dissolving and was coated on the charge transport layer of the photoconductor 2.

<Protective Layer (OCL) Coating Solution> Molecular Sieve 4A was added to 10 parts by mass of a polysiloxane resin composed of 80 mol% of methyl siloxane units and 20 mol% of methyl-phenyl siloxane units, and allowed to stand for 15 hours for dehydration treatment. did. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts by mass of dibutyltin acetate were added thereto to form a uniform solution. To this, 6 parts by mass of dihydroxymethyltriphenylamine was added and mixed, and this solution was applied as a protective layer having a dry film thickness of 2 μm, and cured by heating at 120 ° C. for 1 hour to prepare a photoconductor 3.

Preparation of Photoreceptor 4 The following intermediate layer coating solution was applied onto a cylindrical aluminum substrate by a dip coating method to form an intermediate layer having a dry film thickness of 2 μm.

<Intermediate layer (UCL) coating liquid> The following intermediate layer dispersion liquid is diluted twice with the same mixed solvent, and allowed to stand overnight and then filtered (filter; Rigimesh filter manufactured by Nippon Pall Co., nominal filtration accuracy: 5 microns). , Pressure; 5 N / cm ² )
Then, an intermediate layer composition liquid was prepared.

[0170]   (Preparation of intermediate layer dispersion liquid)   Polyamide resin CM8000 (manufactured by Toray) 1.0 part by mass   Titanium oxide SMT500SAS 3.0 parts by mass   (Made by Teika; surface treatment is silica treatment, alumina treatment, and methyl hydro   Genpolysiloxane treatment)   10 parts by mass of methanol Using a sand mill, dispersion was carried out in batch mode for 10 hours.

Then, the following composition was mixed and dispersed using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm on the intermediate layer.

<Charge Generating Layer (CGL) Coating Liquid> Y-type oxytitanyl phthalocyanine (maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 degrees at 2θ) 20 g Polyvinyl butyral (# 6000-C) , Manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 g t-butyl acetate 700 g 4-methoxy-4-methyl-2-pentanone 300 g Further, the following compositions were mixed and dissolved to prepare a charge transport layer coating solution. This composition liquid was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 24 μm.

<Charge Transport Layer (CTL) Coating Liquid> Charge Transport Material 75 g Polycarbonate Resin 100 g “Iupilon-Z300” (manufactured by Mitsubishi Gas Chemical Co., Inc.) Dioxolane / toluene (10/1 mixed molar ratio) 750 g 2. Method of removing coating layer A. <Use of Removal Tape> Coating Layer Removal Method A-1 A wiping tape and a photosensitive drum are attached to the coating layer removing device of FIG. 7B, and 10 mm from the end of the photosensitive drum rotating at 5 to 30 rpm. 50 minutes in a direction opposite to the rotation direction of the photoconductor drum while contacting a wiping tape with an inclination angle of 1.0 degree with a solvent-soaked wiping tape to the minute coating layer.
The coating layer was removed by moving at a moving speed of 0 to 3000 mm / min until the coating film was removed.

The wiping tape was pressed against 15% of the circumference of the photosensitive drum by two pressing rolls, and 25 N / 20 between the original winding roll and the winding roll.
A tension of mm width was applied.

Coating Layer Removal Method A-2 The same procedure as in Coating Layer Removal Method A-1 above was carried out, except that the photosensitive layer was removed at a tilt angle of 0.0 degrees.

B. <Use of Brush> Removal Method B-1 An electrophotographic photosensitive member is manufactured so that there is an uncoated portion of about 1 cm at the upper end, the process proceeds to the coating layer removal step, and a series of steps as described in FIG. 8 is performed. Performs operation and lower end of base 1 cm
The coating layer of was removed, and the process was transferred to the next drying step to prepare a photoconductor. The solvent in the solvent tank of the coating layer removing device is methylene chloride, which is the same as the solvent for the charge transporting layer, and the 0.5 mm brush made of polyester is rotated as the rubbing member of the coating layer removing base to start coating layer removal. Residual amount of solvent in edge coating layer 1
2.0% (% by mass: 100% by mass of the solvent in the coating liquid state)
And).

Removal method B-2 The same polyester brush as in the removal method B-1 was used as the rubbing member, but when removing the coating layer, a support for removing the coating layer was used.
It was immersed in a solvent tank as in Example 142 of No. 142789, and the lower end coating layer was peeled off.

Four types of the photoconductors 1 to 4 and the removal method A-1
About A-2, B-1 and B-2, it peeled on the combination conditions as shown in Table 1.

The results are shown in Table 1.

[0180]

[Table 1]

* Concavity and convexity in the lateral direction: The difference between the maximum and minimum values of the jaggedness in the circumferential removal when the drum is viewed from above. Evaluation (contact charging roller) <Evaluation conditions> Konica digital copying machine Konica 7
The corona charger of 033 was changed to the following roller charger, and the copy speed was modified to A4, 10 sheets / minute, and the actual copying evaluation was carried out. The conditions are shown below.

(Charging Roller) A charging roller composed of the following conductive elastic member and the like was used on a stainless steel cored bar having a diameter of 8 mm.

The charging roller is No. 1, 2 and 3
In each case, the length in the axial direction (image forming width direction) was shorter than the width of the photosensitive layer, and the length was such that the inner edge was abutted by about 3.0 mm from the edge of the photosensitive layer film.

Charging roller No. 1 As a material for the conductive elastic layer, polynorbornene rubber /
A carbon black / naphthene-based oil and, if necessary, a vulcanizing agent, a vulcanization accelerator, an additive and the like were mixed and prepared, and then filled in a mold to form a conductive elastic layer. On this layer, polyester urethane as a coating layer forming material, particle size of about 0.5
Immersing in a composition liquid consisting of a resin powder (μm), carbon black, and a solvent (methylethylketone / dimethylformamide), coating, drying and heat treatment to form a coating layer made of a urethane layer. Got 1.

Charging roller No. No. 2 except that a resin powder having a particle size of about 8 μm was used as the coating layer forming material instead of the resin powder having a particle size of about 0.5 μm.
In the same manner as in No. 1, the charging roller No. Got 2.

Charging roller No. 3 N except that resin powder having a particle size of about 12 μm was used instead of resin powder having a particle size of about 0.5 μm as the coating layer forming material
o. In the same manner as in No. 1, the charging roller No. Got 3.

The surface roughness Rz of the charging roller thus obtained is measured by a surface roughness meter (Surfcom-550A manufactured by Tokyo Seimitsu Co., Ltd.) and the results are shown in Table 2.

Measurement conditions; Pickup: 0.2 Stylus: 0.8 Cutoff: 0.8 Measuring distance: 4mm Measurement speed: 0.3 / sec

[0189]

[Table 2]

Charging conditions Photoconductor contact pressure: 500 mN / cm DC voltage applied to the charging member: -600 V, AC voltage: 2,000 Vp-p (frequency: 150 Hz) Development condition DC bias: -500 V Dsd (photoconductor And the distance between the developing sleeve); 600 μm Developer layer regulation; Magnetic H-Cut system developer layer thickness; 700 μm Developing sleeve diameter; 40 mm Further, as a fixing method, thermal roll fixing is used, and untransferred remaining on the photoconductor. The toner used the method of cleaning with urethane rubber.

As the transfer paper to be used, paper having a continuous weight of 55 kg was used. The combination of the photoconductor and the charging roller shown in Table 3 below is used for the digital copying machine Kon manufactured by Konica.
It was mounted on a copier of a modified model of ica7033 and the intermittent image output of 10,000 sheets of A4 paper under normal temperature and normal humidity (20 ° C., 60% RH) (1 print and 3 seconds rest) was evaluated. It shows in Table 3.

(1) The evaluation was performed at the start of the evaluation and at the end of copying 10,000 sheets every 5,000 sheets. "RD-918" when using a densitometer
(Manufactured by Macbeth) was used.

Image unevenness: density difference of halftone image (Δ
HD = concentration of 1 cm edge portion−concentration of central portion) ◎ ... 0.05 or less (good) ○ ・ ・ ・ greater than 0.05 and less than 0.1 (no practical problem) × ・..0.1 or more (there is a problem in practical use) Black spot: ◎ ... Black spot frequency of 0.4 mm or more: All copied images are 3 pieces / A4 or less ○ ... Black spot frequency of 0.4 mm or more : 4 pieces / A4 or more, 19 pieces / A4 or less occurred at least 1 sheet (a level at which there is no problem in practical use) × ... Black spot frequency of 0.4 mm or more: 20 pieces / A4 or more occurred at least 1 sheet (in practical use) Peeling of edge film: After the continuous copying, the edge of the photoconductor was observed, and the peeling of the photosensitive layer from the edge was observed.

∘: No peeling of end film ○: Some peeling of end film, but no problem in practical use ×: Peeling of end film, practically problematic Toner contamination Test 10,000 times After the completion of step 1, the image forming apparatus and the surface of the photoconductor were observed to confirm the presence or absence of toner contamination.

∘: No toner scattering was observed ○: Slight toner scattering was observed, but there was no problem in practical use ×: Toner scattering was observed, there was a problem in practical use 10,000 copies of the charging roller Later state: Table 3 shows the result of taking out the charging roller and observing it with the naked eye.

[0196]

[Table 3]

As is clear from Table 3, in the examples of the present invention, image unevenness, toner contamination, black spots, end film peeling,
Also, excellent characteristics with good durability of the charging roller were obtained.

[Example 2] The corona charger of Konica 7033, a digital copying machine manufactured by Konica Corporation, was changed to a magnetic brush charger, and the copying speed was changed to A4, 10 sheets / minute, and the actual copying evaluation was carried out. . The conditions other than the charging condition are the same as the conditions of the charging roller.

(Magnetic Brush Charger) A magnetic brush charger having a structure as shown in FIG. 13 was used.

Preparation of Magnetic Particles Magnetic particles forming a magnetic brush for charging were prepared as follows.

Preparation of magnetic particles 1 Fe ₂ O ₃ : 50 mol% CuO: 24 mol% ZnO: 24 mol% The above are pulverized and mixed, and a dispersant, a binder and water are added to make a slurry, which is then granulated with a spray dryer. After operation and classification, firing was performed at 1125 ° C. The obtained magnetic particles were crushed and then classified to obtain magnetic particles 1 having a volume average particle diameter of 27 μm. The resistance value of the magnetic particles was 2 × 10 ⁷ Ωcm.

Preparation of Magnetic Particles 2 0.05 parts by mass of a titanium coupling agent (isopropoxytriisostearoyl titanate) and methyl ethyl ketone were added to 100 parts by mass of the above-mentioned magnetic particles 1,
After stirring to form an organic coating on the surface of the magnetic particles, the magnetic particles were separated and dried by heating at 180 ° C. Magnetic particles 2 having a volume average particle diameter of 37 μm were obtained. The resistance value of the magnetic particles was 2 × 10 ⁷ Ωcm.

Preparation of Magnetic Particles 3 Magnetite (FeO.Fe _{2) having a} volume average particle diameter of 35 μm
O ₃ ) Magnetic particles 3 were used. Resistance value of magnetic particles is 2 × 1
It was 0 ⁶ Ωcm.

Preparation of Magnetic Particles Fe ₂ O ₃ : 50 mol% MnO: 30 mol% MgO: 20 mol% The above are pulverized and mixed, and a dispersant, a binder and water are added to make a slurry, and the mixture is granulated with a spray dryer. After operation and classification, firing was performed at 1130 ° C. in an atmosphere in which oxygen concentration was adjusted for resistance adjustment. The obtained magnetic particles are crushed and then classified to obtain a volume average particle size of 70.
Magnetic particles 4 having a size of μm were obtained. Resistance value of magnetic particles is 9 ×
It was 10 ⁵ Ωcm.

[0205]

[Table 4]

Method for Measuring Volume Average Particle Diameter of Magnetic Particles The volume average particle diameter of the carrier is typically measured by a laser diffraction type particle size distribution measuring apparatus “Heros (H
ELOS) "(manufactured by SYMPATEC).

Method for Measuring Ratio of Particle Size of ½ or Less of Number Average Particle Size of Magnetic Particles Volume particle size distribution using a laser diffraction type particle size distribution measuring device “HELOS” equipped with the wet disperser. Is measured and converted into a number particle size distribution, and then the ratio of the particle size of 1/2 times or less of the number average particle size is obtained.

Method of measuring resistivity (Ω · cm) Magnetic particles were placed in a container having a cross-sectional area of 0.50 cm ² and tapped, and then 1 kg / cm was put on the packed particles.
^Apply a load of ² , and apply 1000V / between the load and the bottom electrode.
A value obtained by reading the current value when a voltage that causes an electric field of cm is applied.

Each of the magnetic brushes had a length in the axial direction (image forming width direction) that was shorter than the width of the photosensitive layer, and was such that the magnetic brush was in contact with the edge of the photosensitive layer film only about 3.0 mm inside. .

Charging conditions Charging sleeve: Voltage applied to a stainless steel charging sleeve having a diameter of 10 mm; AC voltage superimposed on a DC voltage of 450 V; amount of magnetic particles in charging area; 250 mg / cm ² charging sleeve / linear velocity ratio of photoconductor; 0.8 The combinations of the toner (developer), the photoconductor, and the magnetic brush using magnetic particles shown in Table 6 were mounted on the copying machine of the remodeled machine of the digital copying machine Konica7033 manufactured by Konica Co., Ltd. The image output of 100,000 sheets was evaluated at 20 ° C. and 60% RH.

The evaluation method was the same as for the charging roller. Image unevenness due to deterioration of magnetic particles was also displayed according to the image unevenness of Example-1.

[0212]

[Table 5]

As is clear from Table 5, in the examples of the present invention, no image defects were generated and no deterioration of magnetic particles was observed, and good and excellent images were obtained.

[0214]

EFFECTS OF THE INVENTION According to the present invention, even in the system in which the charging step is performed by contacting the charging member with the electrophotographic photosensitive member, the end shape of the electrophotographic photosensitive member is not peeled off at the end of the coating layer, and the toner accumulation does not occur. None, due to scattering of coating layer powder and toner,
It is possible to provide an electrophotographic image forming method, an image forming apparatus, a process cartridge, and an electrophotographic photosensitive member used therefor, which are free from defects such as black dots.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an electrophotographic photosensitive drum and a specified value used in the present invention.

FIG. 2 is an enlarged schematic sectional view of an end portion of a photosensitive layer.

FIG. 3 is a microscopic sectional shape view of a portion where a photosensitive layer is peeled off by rubbing.

FIG. 4 is a conceptual cross-sectional view of a state in which toner is accumulated or a solidified product thereof is attached.

FIG. 5 is a diagram showing a cleaning range of a photosensitive drum.

FIG. 6 is a schematic view when the wiping tape is tilted and set on the photosensitive drum.

FIG. 7 is a schematic view showing an example of a method of bringing a wiping tape into contact with a photosensitive drum.

FIG. 8 is a sectional view of a coating layer removing device using a brush.

FIG. 9 is a cross-sectional view showing a contact state between a photosensitive drum and a rubbing member.

FIG. 10 is a view showing one form of a rubbing member.

FIG. 11 is an overall configuration diagram of a coating layer removing device.

FIG. 12 is a configuration diagram showing an example of an image forming apparatus to which a charging roller is applied.

FIG. 13 is a configuration diagram of a magnetic brush charger.

14 is a diagram showing a relationship between an AC bias voltage and a charging potential by the charger shown in FIG.

FIG. 15 is an image forming apparatus 1 having a magnetic brush charger.
Sectional view of the example.

[Explanation of symbols]

1 Conductive substrate 2 coating layers 3 photoconductor drum (photoconductor) 4 charging roller 6 Transfer device (transfer roller) 11 Cleaning device 12 cleaning blade 16 Developer 18 Transfer material (transfer paper) 31 wiping tape 38 original roll 39 winding roll 47 transportation means 54 Coating layer removal stand 55 Rubbing member 59 Partition plate 152 Magnetic brush charger D Average length to the end where the coating layer remains P Average value of film thickness in the central part Pmax Average of maximum film thickness outside the image area θ inclination angle

Claims (10)

[Claims] 1. A charging process, an exposing process, a developing process using a developer containing toner, a toner image transferring process, and an electrophotography using an electrophotographic photoreceptor having a coating layer including at least a photosensitive layer on a cylindrical conductive substrate. In an image forming method for forming an image by repeating the step of removing the toner remaining on the photoconductor by a cleaning means, the average value of the coating layer thickness at the central portion of the electrophotographic photoconductor in the image forming width direction is P (μm). ),
The average of the maximum film thickness values outside the image forming area is defined as Pmax (μ
m), assuming that the average value of the distance from the point where the maximum value is formed to the end of the coating layer is D (μm), the shape satisfies both the following formulas (1) and (2). The image forming method, wherein in the charging step, a charging member is brought into contact with the electrophotographic photosensitive member to charge the electrophotographic photosensitive member. Formula (1) 0 <Pmax <2P Formula (2) 2 ≦ (Pmax / D) × 100 ≦ 50 2. An electrophotographic photosensitive member from which the coating layer is removed by bringing a surplus coating layer surface of an electrophotographic photosensitive member in which a coating layer including at least a photosensitive layer is formed on a cylindrical conductive substrate into contact with a rubbing means. In the image forming method, a toner image is formed through a charging step, an exposure step, a developing step using a developer containing toner, and after the transfer to a transfer material, the residual toner is cleaned by a cleaning unit. The average value of the coating layer thickness in the central portion of the photoreceptor in the image forming width direction is P (μm), the average of the maximum film thickness outside the image forming area is Pmax (μm), and the maximum value is formed. Assuming that the average value of the distance from the point where the coating layer is to the end of the coating layer is D (μm), the shape is such that both formulas (1) and (2) below are satisfied, and To charge by contacting the charging member with An image forming method comprising: Formula (1) 0 <Pmax <2P Formula (2) 2 ≦ (Pmax / D) × 100 ≦ 50 3. The image forming method according to claim 1, wherein the means used in the charging step is a charging roller. 4. The image forming method according to claim 1, wherein the means used in the charging step is a magnetic brush. 5. The image forming method according to claim 2, wherein the rubbing means is a brush. 6. The image forming method according to claim 2, wherein the rubbing means is a tape. 7. The cleaning means is a urethane rubber cleaning blade.
7. The image forming method according to any one of items 6 to 6. 8. An image forming apparatus using the image forming method according to claim 1. 9. The image forming apparatus according to claim 8, wherein at least one of a charging unit, an exposing unit, a developing unit, a transferring unit and a cleaning unit is combined with an electrophotographic photosensitive member, and an image forming apparatus main body is provided. A process cartridge characterized in that it is formed so that it can be put in and taken out integrally. 10. An electrophotographic photosensitive member, which is used in the image forming method according to any one of claims 1 to 7.