JP2003066639A - Electrophotographic image forming device, image forming method and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image forming device of a tandem system, by which the deterioration of an image is hardly caused by stably obtaining a high image quality even though it is used for a long time under the various kinds of environments. SOLUTION: In the electrophotographic image forming device of the tandem system, the intermediate layer of a photoreceptor used for each image forming unit is an insulated layer incorporating N-type semiconductive particles and binder and also having a Bernard cell structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, an image forming method and a process cartridge.

[0002]

2. Description of the Related Art In recent years, as an electrophotographic photoreceptor, an organic photoreceptor containing an organic photoconductive substance has been widely used. Organic photoconductors have the advantages that it is easy to develop materials that can be used with various exposure light sources from visible light to infrared light, that materials that do not cause environmental pollution can be selected, and that manufacturing costs are low, but the only drawback Has a low mechanical strength and may cause deterioration or scratches on the surface of the photoconductor when copying or printing a large number of sheets.

In such a photoreceptor, an organic charge generating substance is vapor-deposited on a conductive substrate generally made of aluminum or an aluminum alloy, or an organic charge generating substance and an organic polymer resin are mixed in a solvent for coating. A charge generating layer is formed by applying a liquid or the like to form a charge generating layer, and then applying a coating liquid in which an organic charge transporting substance and an organic polymer resin are mixed in a solvent to form a charge transporting layer. It

Generally, in an electrophotographic image forming apparatus, a photosensitive member is uniformly charged, and then the charge is erased imagewise by exposure to form an electrostatic latent image. To develop and visualize, and then transfer and fix the toner on paper or the like.

As described above, the surface of the photoconductor is electrically and electrostatically charged by the charging device, the developing device, the transfer device, the cleaning device, and the like.
Since mechanical external force is directly applied, durability against them is required. In particular, mechanical durability against abrasion and scratches on the surface of the photoconductor due to rubbing, contamination of foreign matter, film peeling due to impact during paper jam processing, etc. is required. Above all, regarding durability against scratches and film peeling due to impact,
The strength is weaker than that of the inorganic photoreceptor, and its improvement is required.

Further, with the recent development of digital technology, image exposure by a coherent light source such as a laser beam is becoming the mainstream in an image forming method by electrophotography, and interference moire suitable for these coherent light sources is generated. It has been desired to develop an electrophotographic photosensitive member which does not cause abrasion, has high abrasion resistance, is not scratched or peeled off due to an external impact, and causes no image blur.

Particularly in recent years, colorization has been progressing also in electrophotographic image forming apparatuses, but when the color image forming methods having high practicality are roughly classified, transfer drum system, intermediate transfer system, and photoconductor are commonly used. There are four types: a method of making a multicolor superimposed image on the top and a batch transfer (KNC method), and a tandem method. Of course, the above is a name from a certain point of view, so that there are, for example, a tandem type and an intermediate transfer type, and also a type that is directly transferred to a recording material.

Among them, the tandem system, that is, the color image forming apparatus in which each color image is formed by different image forming units and successively transferred, has a wide variety of usable recording materials and high full color quality. Full color images can be obtained at high speed. Especially, the feature that a full-color image can be obtained at a high speed is an advantage not seen elsewhere.

In addition, in order to eliminate black spots by a digital method,
Microparticle-added intermediate layers have been developed.

For example, an electrophotographic photosensitive member is known in which an intermediate layer is provided between a conductive support and a photosensitive layer, and titanium oxide particles are dispersed in a resin in the intermediate layer. or,
A technique of an intermediate layer containing titanium oxide subjected to surface treatment is also known. For example, iron oxide disclosed in JP-A-4-303846, titanium oxide surface-treated with tungsten oxide, titanium oxide surface-treated with an amino group-containing coupling agent disclosed in JP-A-9-96916, and JP-A-9-2584.
Titanium oxide surface-treated with No. 69 organosilicon compound,
Examples thereof include titanium oxide surface-treated with methyl hydrogen polysiloxane described in JP-A-8-328283.

It is known that a Benard cell is generated in a coating film to which fine particles are added. JP-A-3-179362
The publication mentions a method of roughening the surface by generating a cell structure (Benard cell) in the undercoat layer, but there is a description that an image defect occurs because it cannot be controlled. Japanese Patent Laid-Open No. 8-
No. 248651 describes that a Benard cell is generated during dip coating of an undercoat layer, resulting in deterioration of leveling property and deterioration of electrophotographic performance. In general, the occurrence of Benard cells has been regarded as unfavorable and has been reduced. On the other hand, in JP-A-60-32056 and JP-A-60-252359, there are positively described conductive layers and intermediate layers having a Benard cell, but the conductive layers and measures against moire were studied. is there.

[0012]

For example, in the case of a tandem type electrophotographic image forming apparatus using yellow, magenta, cyan and black, four photoconductors are required because each photoconductor is required for each color. Yes, each photoconductor is rubbed by a member in contact with each photoconductor, such as a developer, a cleaning blade, a transfer belt, a separator,
Also, it is affected by ozone and active oxygen generated from the charger. In the tandem type image forming apparatus, a particular problem is deterioration of image quality such as deterioration of sharpness caused by unevenness of durability of the four photoconductors, occurrence of image unevenness, amplification of image misregistration and the like. However, there is a problem that a high quality image is stably provided.

In particular, when the tandem type image forming apparatus is used for a long period of time under high temperature and high humidity, the image quality is remarkably deteriorated.

In the tandem system, a toner having a stable charging property with respect to high image quality and sharpness is preferable, and therefore a toner having a uniform particle size is preferable. The polymerized toner prepared by the polymerization method is generally spherical and has a uniform surface property, so that the toner has high uniformity, but as a drawback, black spots are likely to occur frequently, and the photosensitive layer is Has a large amount of wear and tends to increase the peeling from the end.

The present invention has been made in view of the above problems, and provides a tandem type electrophotographic image forming apparatus which has stable high image quality even when used for a long time in various environments and in which image deterioration does not easily occur. It is provided.

[0016]

The above object can be achieved by any one of the technical means (1) to (24).

(1) A photoreceptor having a conductive substrate and a photosensitive layer, and an intermediate layer between the conductive substrate and the photosensitive layer, and charging for imparting a charge to the surface of the photoreceptor. Means, image exposing means for irradiating the charged area of the photoconductor with light, and an electrostatic latent image is formed on the surface of the photoconductor by the charging means and the image exposing means, and at the same time, on the surface of the photoconductor. Developing means for forming a colored toner image corresponding to the electrostatic latent image using toner, transfer means for transferring the toner image formed on the photoconductor to a transfer target, and residual toner on the surface of the photoconductor An electrophotographic image forming apparatus in which a plurality of image forming units each having a cleaning unit for removing the toner are arranged, and a toner having a different coloring for each image forming unit is used, the intermediate layer contains N-type semiconductor particles and a binder. And Bena An electrophotographic image forming apparatus comprising an insulating layer having a cathode cell structure.

(2) The insulating layer has a film thickness of 0.2 to 15 μm.
m, the electrophotographic image forming apparatus described in (1).

(3) The N-type semiconductor particles have a number average primary particle diameter of 10 to 200 nm (1)
Alternatively, the electrophotographic image forming apparatus according to (2).

(4) The electrophotographic image forming apparatus according to any one of (1) to (3), wherein the N-type semiconductor particles are metal oxides.

(5) The electrophotographic image forming apparatus according to (4), wherein the metal oxide is titanium oxide particles.

(6) The electron according to (5), wherein the titanium oxide particles are surface-treated with silica and / or alumina and then with a reactive organosilicon compound. Photo image forming apparatus.

(7) The electrophotography according to (5), wherein the titanium oxide particles have been subjected to surface treatment a plurality of times, and the final surface treatment is a surface treatment with a reactive organosilicon compound. Image forming apparatus.

(8) At least one surface treatment among the plurality of surface treatments of the titanium oxide particles is a surface treatment of one or more compounds selected from alumina, silica and zirconia ( The electrophotographic image forming apparatus according to 7).

(9) The electrophotographic image forming apparatus described in any one of (6) to (8), wherein the reactive organosilicon compound is methylhydrogenpolysiloxane.

(10) The reactive organosilicon compound is represented by the above general formula (1) (6) to
The electrophotographic image forming apparatus according to any one of (8).

(11) R in the general formula (1) is an alkyl group having 4 to 8 carbon atoms (1)
The electrophotographic image forming apparatus described in 0).

(12) The electrophotographic image forming apparatus according to any one of (5) to (11), wherein the titanium oxide particles are surface-treated with an organic silicon compound having a fluorine atom. .

(13) The electrophotographic image forming apparatus according to any one of (1) to (12), wherein the binder is a polyamide resin.

(14) An image is formed using a toner having a variation coefficient of shape coefficient of 16% or less and a number variation coefficient of 27% or less. (1) to (13) The electrophotographic image forming apparatus described.

(15) 65% by number or more of the toner 1
The electrophotographic image forming apparatus according to any one of (1) to (14), wherein less than 00% by number is a toner having a shape factor of 1.0 to 1.6.

(16) 65% by number or more of the toner 1
The electrophotographic image forming apparatus according to any one of (1) to (14), characterized in that less than 100% by number is a toner having a shape factor of 1.2 to 1.6.

(17) 50% by number or more of the toner 1
The electrophotographic image forming apparatus according to any one of (1) to (16), wherein less than 100% by number is a toner having no corners.

(18) The number average particle diameter of the toner is 3
The electrophotographic image forming apparatus according to any one of (1) to (17), wherein the electrophotographic image forming apparatus has a thickness of 8 μm.

(19) The toner has a histogram showing the particle size distribution (the vertical axis is the number-based frequency, the horizontal axis is the natural logarithm ln (D) (D is the toner particle diameter), and the horizontal axis is 0.23 intervals). And the relative frequency (m1) of the toner particles included in the most frequent class in the histogram showing the number-based particle size distribution divided into a plurality of classes, and the toner particles included in the next most frequent class of the most frequent class. Relative frequency (m
The electrophotographic image forming apparatus according to any one of (1) to (18), characterized in that the sum (M) with 2) is 70% or more based on the whole.

(20) The toner according to any one of (1) to (19), wherein the toner is obtained by polymerizing a polymerizable monomer containing at least a colorant in an aqueous solvent. The electrophotographic image forming apparatus described.

(21) Any one of (1) to (20), wherein the toner is obtained by association in an aqueous solvent in which at least resin particles and a colorant are present.
An electrophotographic image forming apparatus according to the item 1.

(22) The electrophotographic image forming apparatus described in any one of (1) to (21), wherein the toner is made of styrene-acrylate resin or styrene-methacrylate resin.

(23) Any one of (1) to (22)
An image forming method using the electrophotographic image forming apparatus according to the item 1, wherein the transfer process by the transfer unit of each of the image forming units is sequentially performed on the recording material.

(24) Any one of (1) to (22)
A process cartridge for an electrophotographic image forming apparatus according to the item 1, comprising a conductive substrate and a photosensitive layer, and a photoreceptor having an intermediate layer between the conductive substrate and the photosensitive layer, Charging means for applying an electric charge to the surface of the photoconductor, image exposure means for irradiating the charged area of the photoconductor with light, and an electrostatic latent image is formed on the surface of the photoconductor by the charging means and the image exposure means. And a developing means for forming a colored toner image corresponding to a pre-electrostatic latent image on the surface of the photoconductor by using toner, a transfer means for transferring the toner image formed on the photoconductor to a transfer target, and A process cartridge having at least one of a separating unit that separates a transfer target member from the photosensitive member or the transfer unit, and a cleaning unit that removes residual toner on the surface of the photosensitive member.

The present inventors provide a photoreceptor having a conductive substrate and a photosensitive layer by providing an intermediate layer, which is an insulating layer containing N-type semiconductor particles and a binder, between the conductive substrate and the photosensitive layer. It has been found that, since the adhesiveness is improved and the electrical bonding property is improved, the deterioration of the transfer property, the deterioration of the charge retention property, and the peeling of the end portion of the photoconductor can be stably suppressed when the film thickness is worn. . Furthermore, it was found that the potential fluctuation was small under high temperature and high humidity environment. As a result, when the photoconductor of each image forming unit is used in a tandem type image forming apparatus having a plurality of image forming units using this photoconductor, the thickness of the photoconductor of each image forming unit is reduced, and the environment under high temperature and high humidity is further increased. Also in black spots, image density reduction, fog,
Since the occurrence of cracks, deterioration of transferability, and deterioration of charge retention is stably suppressed, deterioration of sharpness that has occurred even with deterioration of one of the photoreceptors conventionally used in the tandem system, It has been found that it is possible to suppress the occurrence of deterioration in image quality such as image unevenness and image misregistration.

Further, in the tandem system, it is necessary to use a toner having stable chargeability with respect to high image quality and sharpness. Therefore, a toner having a uniform particle size is preferable. The polymerized toner prepared by the polymerization method is generally spherical and has a uniform surface property, so that the toner has high uniformity, but as a drawback, black spots are likely to occur frequently, and the photosensitive layer is However, when the polymerized toner is used in the electrophotographic image forming apparatus of the present invention, the occurrence of black spots is suppressed and the high image quality is improved. It was also found that an image with high sharpness can be obtained with.

[0043]

DETAILED DESCRIPTION OF THE INVENTION An electrophotographic image forming apparatus of the present invention,
Embodiments of the image forming method and the process cartridge will be described below with reference to the drawings, but the present invention is not limited thereto. Further, although the following description may include affirmative expressions for terms and the like, they are preferable examples of the present invention and limit the meaning and technical scope of the terms of the present invention. Not a thing.

First, a tandem type electrophotographic image forming apparatus will be described. The electrophotographic image forming apparatus of the present invention,
This is a tandem type electrophotographic image forming apparatus, and has a plurality of image forming units in which coloring is changed for each image forming unit. Each image forming unit has a conductive base and a photosensitive layer, and a photoreceptor having an intermediate layer between the conductive base and the photosensitive layer, and a charge is applied to the surface of the photoreceptor. The charging means for applying, the image exposing means for irradiating the charged area of the photoconductor with light, and the electrostatic latent image on the surface of the photoconductor by the charging means and the image exposing means and the photoconductor. A developing means for forming a colored toner image corresponding to the electrostatic latent image on the surface of the photosensitive member, and a cleaning means for removing the residual toner on the surface of the photosensitive member.

FIG. 1 is a sectional structural view showing an example of a tandem intermediate transfer type electrophotographic image forming apparatus of the present invention.

This example is an apparatus having a drum type intermediate transfer means, and a color image as a developer is superposed on the transfer means 10 to form a color image and then transferred to a recording material (transfer paper P). It is a form of performing.

The transfer means 10 includes four sets of image forming units 20Y, 20M, 20C and 2 arranged around it.
The yellow (Y), magenta (M), cyan (C), and black (K) toner images formed by 0K are sequentially superposed and carried. The transfer means 10 is a drum-shaped transfer body 10, and a conductive rubber layer 12 (thickness 500 to 5000 μm, electric resistance 10 ⁸ to 10 ⁸⁾ as an elastic layer on an aluminum base 11 which is a cylindrical metal base. ¹⁴ Ω ・ c
m urethane rubber layer), and a releasable film 13 (a Teflon (R) layer having a thickness of 20 to 200 μm and an electric resistance of 10 ¹⁰ to 10 ¹⁶ Ω · cm for separation) provided thereon. There is. Around the transfer body 10, four sets of image forming units 20Y, 20M, 20C and 20K, a transfer paper transfer means 30 and a cleaning means 16 are respectively arranged. The transfer body 10 is rotatably supported by the color image forming apparatus 100 by a shaft 101.

Further, the four sets of image forming units 20Y,
20M, 20C, and 20K are frame bodies 26Y, 26M, and
26C and 26K, and the frame bodies 26Y and 26M,
26C and 26K are movably provided in the color image forming apparatus 100, and each image forming unit is moved to the image transfer position or the non-image transfer position with respect to the drum-shaped transfer body 10 according to the color used. Moving members 27Y, 2 for
7M, 27C and 27K are frame bodies 26Y, 26M and 26, respectively.
It is provided in contact with C and 26K.

The four sets of image forming units 20Y, 20
M, 20C and 20K are photosensitive drums 21Y and 21M,
21C, 21K as a center of rotation, charging means 22Y, 2
2M, 22C, 22K and image exposure means 23Y, 23M,
23C and 23K, and rotating developing means 24Y and 24M,
24C, 24K, and the photoconductor drums 21Y, 21M,
Cleaning means 2 for cleaning 21C and 21K
It is composed of 5Y, 25M, 25C and 25K.

The image forming units 20Y, 20M, 2
0C and 20K have the same configuration except that the colors of the toner images formed on the transfer body 10 are different, and the image forming unit 20Y will be described in detail with reference to FIG.

Image forming unit 2 provided in the frame 26Y
0Y is around the photosensitive drum 21Y which is an image forming body,
Image forming member charging means 22Y (hereinafter, simply charging means 22Y,
Alternatively, a charger 22Y), an exposure unit 23Y, a developing unit 24Y, and an image forming member cleaning unit 25Y (hereinafter simply referred to as a cleaning unit 25Y or a cleaning blade 25Y) are arranged, and the photoconductor drum 2 is arranged.
A yellow (Y) toner image is formed on 1Y. Further, in the present embodiment, of the image forming unit 20Y, at least the photosensitive drum 21Y, the charging unit 22Y, the developing unit 24Y, and the cleaning unit 25.
It is provided so that Y is integrated.

The charging means 22Y is a means for applying a uniform electric potential to the photoconductor drum 21Y, and in the present embodiment, a roller-shaped charger that rotates while being in contact with the photoconductor drum 21Y. 22Y is used.

The image exposure means 23Y is a roller-shaped charger 2.
Photoreceptor drum 21 to which uniform potential is applied by 2Y
Exposure on Y based on the image signal (yellow),
The exposing means 23Y is a means for forming an electrostatic latent image corresponding to a yellow image, and the exposing means 23Y includes the photosensitive drum 21.
A device including LEDs in which light emitting elements are arranged in an array in the Y-axis direction and an imaging element (trade name; SELFOC lens), or a laser optical system is used.

The developing means 24Y is means for accommodating yellow toner which is a developer and for reversing and developing the electrostatic latent image formed on the photosensitive drum 21Y to form a yellow toner image. In the developing means 24Y of the present embodiment,
The yellow toner contained in the developing means 24Y is
After stirring by the stirring member 241Y, the toner supply roller 242 whose surface that rotates in the direction of the arrow is elastic (sponge)
Y supplies the developing sleeve 243Y. At this time, the developing layer 243Y is formed by the thin layer forming member 244Y.
The upper yellow toner is made into a uniform thin layer. Developing means 24
In the developing action of Y, a developing bias in which a direct current or an alternating current is applied is applied to the developing sleeve 243Y rotating in the direction of the arrow, and jumping developing is performed by one component accommodated in the developing means 24Y and grounded. A bias in which a direct current component and an alternating current component having the same polarity as that of the toner are superimposed is applied to the photosensitive drum 21Y being operated, and non-contact reversal development is performed. The developing sleeve 243
Abutting rollers provided at both ends outside the image area of Y come into contact with the photoconductor drum 21Y, so that the developing sleeve 2
43Y and the photoconductor drum 21Y are kept in non-contact with each other.
Note that contact development can be used instead of non-contact development.

In the yellow toner image formed on the photosensitive drum 21Y, the abutting roller rotates while contacting the positioning portion of the transfer body 10, and the transfer body 10 to which a bias voltage having a polarity opposite to that of the toner is applied. Thus, the images are sequentially transferred onto the transfer body 10.

The cleaning means 25Y is arranged so that after the yellow toner image is transferred onto the transfer body 10, the photosensitive drum 21
It is a means for removing the yellow toner remaining on Y from the photosensitive drum 10. In this embodiment, the cleaning means 25Y slides on the photosensitive drum 21Y to remove the residual toner. Is going.

In this way, the image forming unit 20Y
Thus, the yellow toner image corresponding to the image signal (yellow) formed by the processes of charging, exposing, and developing is transferred onto the transfer body 10.

Then, as shown in FIG. 1, the other image forming units 20M, 20C, and 20K similarly have magenta toner images corresponding to image signals (magenta) on the photosensitive drums 21M, 21C, and 21K, respectively. Cyan toner image corresponding to image signal (cyan), image signal (K)
The black toner image corresponding to is formed in parallel processing in synchronization. By such an operation, the toner images formed on the photoconductor drums 21Y, 21M, 21C, and 21K of the image forming units 20Y, 20M, 20C, and 20K are sequentially transferred by applying a transfer bias of 1 to 2 kV. It is transferred onto the body 10 and the toner images are superimposed. When all the toner images are superposed, a color toner image is formed on the transfer body 10.

On the other hand, below the transfer body 10, there is provided a paper feed cassette CA which is a transfer material storage means, and the transfer paper P which is the transfer material housed in the paper feed cassette CA is fed by the paper feed roller r1. By the operation, it is carried out of the paper feed cassette CA and sent to the timing roller pair r2. The timing roller pair r2 sends out the transfer paper P in synchronization with the color toner image formed on the transfer body 10.

The transfer paper P sent out is transferred with the color toner image formed on the transfer body 10 by the transfer paper transfer means 30 at the transfer position. This transfer paper transfer means 30
Grounded roller 31, transfer belt 32, paper charger 3
3, a transfer electrode 34, and a paper separation AC static eliminator 35.

The transferred transfer paper P is stretched around the roller 31 and is conveyed to the transfer position by the transfer belt 32 which rotates in the direction of the arrow in synchronization with the peripheral speed of the transfer body 10. The transfer belt 32 is a belt having a high resistance of 10 ⁶ to 10 ¹⁰ Ω · cm. At this time, the transfer paper P is charged to the same polarity as the toner by the paper charger 33 as a transfer material charging means, adsorbed to the transfer belt 32 and fed to the transfer position. By charging the paper with the same polarity as that of the toner, it is possible to prevent the color toner image on the transfer body 10 from being attracted to each other and prevent the color toner image from being disturbed. Also,
As the transfer material charging means, an energizing roller that can be brought into contact with or separated from the transfer belt 32 or a brush charger can be used.

At the transfer position, the transfer electrode 34 transfers the color toner image on the transfer body 10 onto the transfer paper P. By the transfer electrode 34, corona discharge is performed on the back surface of the transfer paper P so that the potential becomes 1.5 to 3 kV, which is a voltage having a polarity opposite to that of the toner higher than the bias of the transfer body 10.

The transfer paper P on which the color toner image has been transferred
Is further transported by the transfer belt 32, discharged by a paper separation AC static eliminator 35 for separating the transfer material, separated from the transfer belt 32, and transported to the fixing unit 40. In the fixing means 40, the color toner image is heated and pressure-bonded by the heating roller 41 and the pressure roller 42, and the color toner image is deposited and fixed on the transfer paper P.
Then, the sheet is discharged onto a tray provided on the upper portion of the color image forming apparatus.

On the other hand, the transfer body 10 on which the color toner image is transferred onto the transfer paper P is rubbed on the transfer body 10 by the cleaning blade 161 which is the transfer body cleaning means 16, and remains on the transfer body 10. Remove toner
To be cleaned. Further, a blade is slidably contacting the transfer belt 32 as a transfer belt cleaning unit 36,
The transfer belt 32 after the paper separation is cleaned.

The image forming unit shown in FIG. 2 has the developing means and the photosensitive drum as a process cartridge which can be detached from the image forming unit, but the process cartridge is not limited to this in the present invention. A process cartridge having at least one of a photoconductor, a charging unit, an image exposing unit, a developing unit, a transferring unit, a separating unit, and a cleaning unit may be used.

FIG. 3 is a sectional view of an image forming unit which is a little different from that in FIG. 2 in which the developing means and the photoconductor drum can be replaced by a process cartridge which can be attached to and detached from the image forming unit.

This embodiment will be described by taking the configuration of the image forming unit 20C as an example. A frame 26C that constitutes the image forming unit 20C is provided on a guide member 111 provided on the color image forming apparatus, and a moving member 27C having a cam structure is provided so as to contact a part of the frame 26C, The image forming unit 20C together with the frame 26C is stopped at a predetermined image forming position against the spring SC. Frame 2
6C is provided with a charging unit 22C and an exposure unit 23C around a photoconductor drum 21C which is an image forming body, and a second frame body 261C which is detachably attached to the frame body 26C and serves as a replaceable process cartridge. Inside the developing means 24
C, a developer supplying unit 241C, and a developer stirring unit 242C are provided respectively, and the developing unit 24C is arranged so as to face the periphery of the photosensitive drum 21C.

Further, a cyan (C) toner made of the one-component developer T is built in the second frame 261C, and the remaining amount of the developer for detecting the remaining amount of the one-component developer T is detected. The means A is provided in the developing means 24C.

A cyan (C) toner image is formed on the photosensitive drum 21C by the image forming process,
As described above, the cyan (C) toner image is transferred onto the transfer body 10 from the photosensitive drum 21C, and then the periphery of the photosensitive drum 21C is cleaned by the cleaning unit 25C.

FIG. 4 shows an image forming apparatus for directly transferring to a recording material on a transfer belt. The image forming procedure of FIG.
3 is almost the same as that of No. 3, except that it is directly transferred to the recording material instead of the intermediate transfer member.

An image forming apparatus for directly transferring to the recording material on the transfer belt of FIG. 4 will be described. Four sets of photoconductors are arranged in parallel, and yellow (Y), magenta (M), cyan (C),
This is an example of color image formation by a tandem color image forming apparatus in which four color toner images of black (K) are sequentially transferred.

According to FIG. 4, the photosensitive drum 21Y (21
M, 21C, 21K), scorotron charger (charging means) 22Y (22M, 22C, 22K), exposure optical system (exposure means), developing device (developing means) 24Y (24M, 2M)
4C, 24K) and a cleaning device (cleaning means) 25Y (25M, 25C, 25K),
M, C and K image forming units 20Y (20M, 20
C, 20K), the toner images formed by the Y, M, C, and K toner image forming units are supplied with the recording material (recording paper P) at the same timing, and a transfer device 34Y (transferring means) is provided. 34M, 34C, 34K) to form a superimposed color toner image.

The recording material is conveyed on a conveyor belt 115, and a paper separation AC static eliminator 161 as recording material separating means.
The charge is removed from the conveyor belt and the separation claw 210, which is a separation member provided in the conveyor 160 at a predetermined interval, separates the conveyor belt.

Further, after passing through the conveying section 160, it is conveyed to a fixing device (fixing means) 40 composed of a heating roller 41 and a pressure roller 42, and is formed by the addition fixing roller 41 and the pressure roller 42. The recording paper P is nipped by the nip portion T, and heat and pressure are applied to the recording paper P.
After the upper superimposed toner image is fixed, it is ejected out of the apparatus.

Next, the structure of the photoconductor used in the electrophotographic image forming apparatus of the present invention will be described in more detail.

The photoconductor used in the present invention has a conductive substrate and a photosensitive layer, and has an intermediate layer between the conductive substrate and the photosensitive layer. Further, the intermediate layer is an insulator containing N-type semiconductor particles and a binder and having a Benard cell structure.
The intermediate layer has good adhesion between the conductive support and the photosensitive layer,
Good electron injection from the photosensitive layer to the conductive support, mobility,
And has a barrier function of preventing hole injection from the support.

The Benard cell structure according to the present invention (hereinafter sometimes simply referred to as Benard cell) means that it has a polygonal shape or a partially polygonal shape when observed from the surface side, It preferably has a hexagonal shape. Among polygons, the proportion of hexagons is preferably 10 to 100% (on a number basis), preferably 2
0-100% is good.

The size of the Benard cell according to the present invention is preferably about 10 to 500 μm at the longest part.

The size and depth of the Benard cell in the intermediate layer according to the present invention can be controlled by appropriately adjusting the viscosity, surface tension, solvent composition, type of the intermediate layer dispersion, coating amount, film thickness, drying conditions and the like. It can be done by selecting.

When the dispersion has a high viscosity exceeding the above range or a low viscosity below the lower limit, the solvent contained in the coating layer evaporates and the coating layer is solidified. No convection of the dispersion liquid in the coating layer occurs, or the degree of convection is too low, and thus the dispersion liquid may not be formed.

The film thickness of the intermediate layer according to the present invention is preferably 0.2 to 15 μm and coated and dried as described above, more preferably 0.3 to 10 μm, and further 0.5 to.
8 μm is preferable.

When the film thickness is 0.2 μm or more, the solvent contained in the coating layer is less likely to evaporate, and the convection of each component in the coating layer generated during the solidification of the coating layer is promoted. The difference in the surface tension and the difference in the buoyancy between the upper and lower surfaces of the coating layer, which becomes the force, become remarkable, and the cells are easily formed on the surface. Further, by setting the film thickness to 15 μm or less, in the drying step of the coating layer, even after the surface of the coating layer is solidified, the solvent in the coating layer is less likely to evaporate due to forced drying, and foaming or cracking occurs in the layer. It becomes difficult, and it becomes easy to form uniformly on the surface.

The N-type semiconductor particles used in the present invention preferably have a number average primary particle size of 10 nm or more and 200 nm or less, more preferably 15 nm or more and 150 nm or less.

The N-type semiconductor particles used in the present invention are 1
When the thickness is 0 nm or more, a Benard cell can be generated, and the effect of preventing black spots from being generated by the intermediate layer is increased. On the other hand, when it is less than 200 nm, the uniformity of the Benard cell is improved, and the increase of black spots can be suppressed.
An intermediate layer coating solution using N-type semiconductor particles having a number average primary particle size in the above range has good dispersion stability, and an intermediate layer formed from such a coating solution and having a Benard cell prevents black spots from occurring. In addition to its function, it has good environmental characteristics and has cracking resistance.

The number average primary particle size of the N-type semiconductor particles is
For example, in the case of titanium oxide, it is a measurement value as a Feret direction average diameter obtained by observing 100 particles as primary particles randomly by enlarging by 10,000 times by observation with a transmission electron microscope.

The N-type semiconductor particles used in the present invention include titanium oxide (TiO ₂ ) and zinc oxide (Zn oxide).
It is preferable to use metal oxide particles such as O) and tin oxide (SnO ₂ ). Among them, titanium oxide is preferable, and N which has been surface treated to achieve good dispersibility.
Type semiconductor particles are preferred. Titanium oxide particles that have been surface-treated are particularly preferable. The content of particles in the intermediate layer is
The volume ratio is preferably 10% to 90%, further 25
% To 75% is preferable.

Here, the N-type semiconductor particles are fine particles having a property that the conductive carriers are electrons. That is,
The property that the conductive carriers are electrons means that the N-type semiconductor particles are contained in an insulating binder to efficiently block hole injection from the substrate and block electrons from the photosensitive layer. It has a property that does not show sex.

The surface treatment of the N-type semiconductor particles is preferably performed by coating the surface of the N-type semiconductor particles with a metal oxide, a reactive organosilicon compound, an organometallic compound or the like.

The titanium oxide particles have a dendritic shape, a needle shape, a granular shape, and the like. Titanium oxide having such a shape has anatase type, rutile type, amorphous type, and the like as crystal types. Any shape and crystal type may be used, and two or more shapes and crystal types may be mixed and used.

Surface treatment performed on the N-type semiconductor particles of the present invention
One of the reasons is that it is preferable to perform the surface treatment multiple times,
And the last surface treatment in the plurality of surface treatments is a reaction
It is preferable to perform surface treatment with a hydrophilic organosilicon compound.
Yes. In addition, at least once in the plurality of surface treatments
The surface treatment of alumina (Al₂O₃), Silica (Si
O ₂), And zirconia (ZrO₂) Less selected from
Both are done with one or more compounds, and finally reactive
To be surface treated with an organosilicon compound
Is preferred. Note that these compounds also have hydrates.
Also included.

As another method of the surface treatment of the N-type semiconductor particles of the present invention, the surface treatment is performed a plurality of times, and the last surface treatment is performed in the plurality of surface treatments. It is preferable to perform surface treatment using a reactive organic titanium compound or a reactive organic zirconium compound. Further, among the plurality of surface treatments, at least one surface treatment is performed using at least one compound selected from alumina, silica, and zirconia as described above, and finally, a reactive organotitanium compound or It is preferable to perform surface treatment with a reactive organozirconium compound.

In this manner, the surface treatment of N-type semiconductor particles such as titanium oxide particles is performed at least twice, so that the surface of the N-type semiconductor particles is uniformly coated (treated), and the surface-treated N-type semiconductor particles are treated. When the type semiconductor particles are used in the intermediate layer according to the present invention, a good photoreceptor having good dispersibility of N type semiconductor particles such as titanium oxide particles in the intermediate layer and not causing image defects such as black spots is obtained. It is possible and preferable.

In the present invention, in particular, the surface treatment is carried out a plurality of times by using alumina and silica, and then the surface treatment is carried out by a reactive organosilicon compound, or a surface treatment by using alumina and silica. What is subjected to a surface treatment with a reactive organic titanium compound or a reactive organic zirconium compound after the above is particularly preferable.

The above-mentioned treatment of alumina and silica may be carried out at the same time, but especially the treatment of alumina is carried out first.
Next, it is preferable to perform silica treatment. Further, the treatment amount of alumina and silica in the case of performing treatment of alumina and silica is preferably such that the amount of silica is larger than that of alumina.

The surface treatment of the N-type semiconductor particles such as titanium oxide described above with a metal oxide such as alumina, silica and zirconia can be carried out by a wet method. For example, silica,
Alternatively, the N-type semiconductor particles that have been subjected to the surface treatment of alumina can be manufactured as follows.

When titanium oxide particles are used as the N-type semiconductor particles, titanium oxide particles (number average primary particle diameter: 50 n
m) is dispersed in water at a concentration of 50 to 350 g / L to give an aqueous slurry, to which a water-soluble silicate or a water-soluble aluminum compound is added. Then, neutralize by adding an alkali or an acid, silica on the surface of the titanium oxide particles,
Alternatively, alumina is precipitated. Subsequently, filtration, washing and drying are performed to obtain the target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. on the other hand,
When aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.

The amount of the metal oxide used in the surface treatment is 0.1 to 5 with respect to 100 parts by mass of N-type semiconductor particles such as titanium oxide particles in the charged amount during the surface treatment.
0 parts by mass, more preferably 1 to 10 parts by mass of metal oxide is preferably used. Even when the above-mentioned alumina and silica are used, for example, in the case of titanium oxide particles, it is preferable to use 1 to 10 parts by mass with respect to 100 parts by mass of titanium oxide particles, and the amount of silica is larger than that of alumina. preferable.

The surface treatment with the reactive organosilicon compound, which is performed after the surface treatment with the above metal oxide, is preferably performed by the following wet method.

That is, the titanium oxide treated with the metal oxide is added to a solution prepared by dissolving or suspending the reactive organosilicon compound in an organic solvent or water, and the solution is stirred for a few minutes to 1 hour. To do. Then, in some cases, the liquid is subjected to a heat treatment, subjected to a process such as filtration and then dried to obtain titanium oxide particles whose surface is coated with an organosilicon compound. The reactive organic silicon compound may be added to a suspension of titanium oxide dispersed in an organic solvent or water.

In the present invention, the surface of titanium oxide particles is coated with a reactive organic silicon compound,
Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Au)
ger), secondary ion mass spectrometry (SIMS), and diffuse reflection FI-IR.

The amount of the reactive organosilicon compound used for the surface treatment is 0 for 100 parts by mass of titanium oxide treated with the metal oxide in the charged amount at the time of the surface treatment. 1 to 50 parts by mass, more preferably 1 to 10 parts by mass. When the amount of surface treatment is less than the above range, the surface treatment effect is not sufficiently imparted, and the dispersibility of titanium oxide particles in the intermediate layer deteriorates.
Further, if it exceeds the above range, the electric performance is deteriorated, and as a result, the residual potential increases and the charging potential decreases.

As the preferred reactive organosilicon compound used in the present invention, the organosilicon compound represented by the above general formula (1) is used.

In the organosilicon compound represented by the general formula (1), an organosilicon compound in which R is an alkyl group having 4 to 8 carbon atoms is more preferred, and a specific preferred compound example is trimethoxy. Examples thereof include n-butylsilane, trimethoxy i-butylsilane, trimethoxyhexylsilane, and trimethoxyoctylsilane.

Other preferred reactive organosilicon compounds used in the present invention include hydrogen polysiloxane compounds. The hydrogen polysiloxane compound having a molecular weight of 1,000 to 20,000 is generally easily available and has a good black spot preventing function. In particular, when methylhydrogenpolysiloxane is used for the final surface treatment, good effects can be obtained.

The surface treatment of the titanium oxide particles used in the present invention is preferably a surface treatment with an organic silicon compound having a fluorine atom. It is preferable to carry out the surface treatment with the organosilicon compound having a fluorine atom and the above-mentioned wet method.

That is, the above-mentioned organosilicon compound having a fluorine atom is dissolved or suspended in an organic solvent or water, untreated titanium oxide is added thereto, and such a solution is stirred for about several minutes to 1 hour. Then, the mixture is mixed, and if necessary subjected to heat treatment, dried through a step such as filtration to coat the titanium oxide surface with an organosilicon compound having a fluorine atom. The organosilicon compound having a fluorine atom may be added to a suspension prepared by dispersing titanium oxide in an organic solvent or water.

Incidentally, the fact that the titanium oxide surface is coated with an organic silicon compound having a fluorine atom means that
Photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Au)
ger), secondary ion mass spectrometry (SIMS), and diffuse reflection FI-IR.

Examples of the fluorine-containing organosilicon compound used in the present invention include 3,3,4,4,5,5,5.
6,6,6-nonafluorohexyltrichlorosilane,
3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldichlorosilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3,3,4,4,5 , 5, 6, 6,
6-nonafluorohexyl methyl dichlorosilane etc. are mentioned.

In the present invention, the N-type semiconductor particles may be subjected to the last surface treatment with a reactive organic titanium compound or a reactive organic zirconium compound. The method is carried out by a method similar to the surface treatment method with the above reactive organosilicon compound.

The fact that the surface of the N-type semiconductor particles is coated with a reactive organic titanium compound or a reactive organic zirconium compound means that photoelectron spectroscopy (ESCA),
It is confirmed with high accuracy by using a combination of surface analysis methods such as Auger electron spectroscopy (Auger), secondary ion mass spectrometry (SIMS), and diffuse reflection FI-IR.

Next, N-type semiconductor particles such as titanium oxide particles that have been subjected to the above-mentioned surface treatment (hereinafter also referred to as surface-treated N-type semiconductor particles. In particular, surface-treated titanium oxide particles are subjected to surface treatment. The structure of the intermediate layer using titanium oxide) will be described.

An example of the intermediate layer of the photoconductor used in the present invention is one in which surface-treated N-type semiconductor particles such as surface-treated titanium oxide obtained by performing the above-mentioned plurality of surface treatments are dispersed in a solvent together with a binder resin. It is prepared by coating the above liquid on a conductive support.

The intermediate layer is an insulating layer, and the insulating layer means that the volume resistance is 1 × 10 ⁸ to 10 ¹⁵ Ω · cm. Therefore, the volume resistance of the intermediate layer of the present invention is preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, more preferably,
2 × 10 ⁹ to 1 × 10 ¹³ Ω · cm is preferable. The volume resistance can be measured as follows.

Measurement conditions: JIS: C2318-1975
According to. Measuring instrument: Hiresta IP manufactured by Mitsubishi Petrochemical Co., Ltd. Measuring condition: Measuring probe HRS Applied voltage: 500 V Measuring environment: 20 ± 2 ° C., 65 ± 5 RH% When the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer decreases. However, the generation of black spots increases and the potential holding property of the electrophotographic photosensitive member also deteriorates, so that good image quality cannot be obtained. On the other hand, if it is larger than 10 ¹⁵ Ω · cm, the residual potential is likely to increase due to repeated image formation, and good image quality cannot be obtained.

As the binder of the intermediate layer of the photoreceptor used in the present invention, polyamide resin, vinyl chloride resin, vinyl acetate resin, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, melamine resin, epoxy resin, alkyd resin, etc. And a copolymer resin containing two or more of repeating units of these resins. Among these binders, a polyamide resin is particularly preferable, and an alcohol-soluble polyamide obtained by copolymerization, methoxymethylation or the like is particularly preferable. The surface treatment N of the present invention dispersed in the binder
For example, in the case of surface-treated titanium oxide, the amount of type semiconductor particles is 10 to 1 with respect to 100 parts by mass of the binder resin.
It is 50,000 parts by mass, preferably 50 to 1,000 parts by mass. By using the surface-treated titanium oxide in this range, the dispersibility of the titanium oxide can be kept good, and a good intermediate layer without black spots can be formed.

The thickness of the insulating layer which is the intermediate layer of the present invention is 0.
2 to 15 μm is preferable. By using the film thickness within the above range, it is possible to form an intermediate layer having good electrophotographic characteristics without causing black spots.

The coating solution for the intermediate layer prepared to form the intermediate layer of the present invention is the surface-treated N such as the surface-treated titanium oxide.
Although it is composed of mold semiconductor particles, a binder resin, a dispersion solvent, and the like, as the dispersion solvent, the same solvent as that used in the production of other photosensitive layers is appropriately used.

That is, the solvent or dispersion medium used for forming the intermediate layer, photosensitive layer and other resin layer of the present invention is n-
Butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylketone, methylisopropylketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1 , 2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, Methyl cellosolve and the like can be mentioned.

The solvent for the coating liquid for the intermediate layer is not limited to these, but methanol, ethanol, butanol, 1-propanol, isopropanol and the like are preferably used. Further, these solvents can be used alone or as a mixed solvent of two or more kinds.

As the solvent for coating the intermediate layer, it is preferable to use a mixed solvent of methanol and a linear alcohol, which has high resin solubility, in order to prevent uneven drying during coating of the intermediate layer. The ratio of the linear alcohol to the methanol is 1 to 0.05 by volume.
A mixture of 6 is preferable. By using the coating solvent as a mixed solvent in this way, the evaporation rate of the solvent can be appropriately maintained, and the occurrence of image defects due to uneven drying during coating can be suppressed.

As the dispersing means for the surface-treated titanium oxide used for preparing the coating solution for the intermediate layer, any dispersing means such as a sand mill, a ball mill or ultrasonic dispersing may be used.

As the coating processing method for producing the electrophotographic photosensitive member of the present invention including the intermediate layer, dip coating,
Although coating processing methods such as spray coating and circular amount regulation type coating are used, the coating processing on the upper layer side of the photosensitive layer does not dissolve the lower layer film as much as possible, and in order to achieve uniform coating processing, spray coating or circular coating It is preferable to use a coating processing method such as regulated coating (a circular slide hopper is a typical example). Regarding the spray coating, for example, JP-A-3-
No. 90250 and JP-A-3-269238, and the circular amount control type coating is described in detail, for example, in JP-A-58-189061.

Next, the conductive substrate of the photoconductor used in the present invention will be described. The conductive substrate used for the photosensitive member of the electrophotographic image forming apparatus of the present invention may be either a sheet shape or a cylindrical shape, but in order to design the image forming apparatus compactly, the cylindrical conductive substrate Is preferred.

The cylindrical conductive substrate used in the present invention means a cylindrical substrate required to be able to form an image endlessly by rotating, and has a straightness of 0.1 mm or less and a shake of 0.1 mm or less. Conductive substrates in the range are preferred. 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.

Next, the photosensitive layer of the photoconductor used in the present invention will be described. The photosensitive layer of the photoreceptor used in the present invention may have 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 more preferably the photosensitive layer. It is preferable that the function of 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 charge generation layer contains one or more charge generation substances (CGM). If necessary, a binder resin and other additives may be contained as other substances.

As the charge generating substance (CGM), a known charge generating substance (CGM) can be used. For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azurenium pigment or the like can be used. Among these, CGM that can minimize the increase in residual potential with repeated use
Has a steric structure and a potential structure capable of forming a stable aggregation structure among a plurality of molecules, and specific examples thereof include a phthalocyanine pigment and a perylene pigment CGM having a specific crystal structure. For example, the Bragg angle 2θ with respect to Cu-Kα rays
CGMs such as titanyl phthalocyanine, which has a maximum peak at 27.2 °, and benzimidazole perylene, which has a maximum peak at 22.4, have almost no deterioration due to repeated use, and the increase in residual potential can be reduced. .

When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferable resin is formal resin, butyral resin, silicon resin, silicon modified butyral resin, phenoxy resin. Resin etc. are mentioned. The ratio of the binder resin to the charge generating substance is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin.
By using these resins, the increase in residual potential due to repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 to 2 μm.

The charge transport layer contains a charge transport material (CTM) and a binder resin for dispersing CTM to form a film.
Other substances may optionally contain additives such as antioxidants.

As the charge transport material (CTM), a known charge transport material (CTM) can be used. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, CTM that can minimize the increase in residual potential due to repeated use has high mobility and has a characteristic that the difference in ionization potential with CGM to be combined is 0.5 (eV) or less, and preferably 0. It is 0.25 (eV) or less.

The ionization potentials of CGM and CTM are measured by a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd. Resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, poly-N
-Polymer organic semiconductors such as vinylcarbazole.

The most preferable binder for these CTLs is a polycarbonate resin. Polycarbonate resin is most preferable in simultaneously improving abrasion resistance, CTM dispersibility, and electrophotographic characteristics. The ratio of the binder resin to the charge transport material is the binder resin 1
10 to 200 parts by mass is preferable with respect to 00 parts by mass. or,
The thickness of the charge transport layer is preferably 10 to 40 μm.

Although the most preferable photoconductor layer structure of the present invention has been described above, a photoconductor layer structure other than the above may be used in the present invention.

Although any toner can be used in the present invention, the toners described below are preferable for achieving the effects of the present invention.

In the toner used in the present invention, the ratio of the toner particles whose shape factor is in the range of 1.0 to 1.6 is 65.
It is preferable to adjust to a number% or more, more preferably 70 number% or more, and the shape factor is 1.
The ratio of toner particles in the range of 2 to 1.6 is 65 number%
It is preferable that the content is not less than 70%, and more preferably 70% by number or more.

By adjusting the toner particles used in the present invention within this range, the packing density of the toner particles in the transferred toner layer becomes high, and the transferability between the respective colors is improved for the retransfer to the image forming support. There is little change, and good transferability can be maintained. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized, so that there is little variation in adhesion between the colors and the color image can be stabilized. The “shape factor” of the toner of the present invention described above is represented by the following formula, and indicates the degree of roundness of toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter means the parallel line when a projected image of toner particles on a plane is sandwiched by two parallel lines. Refers to the width of the particles at which the interval is maximum. The projected area means the area of the projected image of the toner particles on the plane.

In the present invention, this shape factor is determined by taking a photograph of the toner particles magnified 2000 times with a scanning electron microscope, and then using this photograph, "SCANNING" is taken.
It was measured by analyzing a photographic image using "IMAGE ANALYZER" (manufactured by JEOL Ltd.). At this time, the shape factor according to the present invention was measured by the above calculation formula using 100 toner particles.

The method of controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy by impact force in a gas phase of the toner particles, a toner Is added to a solvent that does not dissolve, and a swirl flow is applied to control the conditions in these production methods to obtain a shape factor of 1.
There is a method in which toner particles having a particle size of 0 to 1.6 or 1.2 to 1.6 are prepared and added to a normal toner so as to be within the range of the present invention, and then adjusted.

Further, toner particles whose overall shape is controlled at the stage of preparing a so-called polymerization toner and whose shape coefficient is adjusted to 1.0 to 1.6 or 1.2 to 1.6 are likewise used for ordinary toners. There is a method of adding and adjusting.

Of the above methods, the polymerization toner is preferable because it is simple as a production method, and the surface uniformity is excellent as compared with the pulverized toner.

The toner used in the present invention preferably contains toner particles having no corners in a proportion of 50% by number or more and less than 100% by number, more preferably 70% by number or more. It is less than 100% by number.

By adjusting the ratio of the toner particles having no corners to this ratio, the voids of the toner layer (powder layer) transferred to the intermediate transfer member are reduced, and the toner particles can be transferred to the image forming support again. Transferability is improved and image quality is stabilized. Further, the toner particles that are easily worn or broken and the toner particles having a portion where the electric charge is concentrated are reduced, the charge amount distribution becomes sharp, the chargeability becomes stable, and good image quality can be formed for a long time.

In the present invention, "toner particles having no corners"
The term “toner particles that do not substantially have protrusions where electric charges are concentrated or protrusions that easily wear due to stress” is specifically referred to as “toner particles without corners” below. That is, as shown in FIG. 5A, when the major axis of the toner particle T is L, a circle C having a radius (L / 10) is in contact with the peripheral line of the toner particle T at one point inside. The case where the circle C does not substantially protrude to the outside of the toner T when the inside is rolled is referred to as “toner particles without corners”. The term “when substantially not protruding” means a case where there is one or less protrusions with protruding circles.
Further, the “major axis of toner particles” refers to the width of particles at which the distance between the parallel lines becomes maximum when the projected image of the toner particles on a plane is sandwiched by two parallel lines. Note that FIG.
(B) and (c) show examples of projected images of toner particles having corners.

The ratio of toner particles having no corners is measured as follows. First, a photograph of a magnified toner particle is taken with a scanning electron microscope and further magnified to 15,000.
A 0x photographic image is obtained. Then, the presence or absence of the above-mentioned corner is measured for this photographic image. This measurement is performed on 100 toner particles.

The method for obtaining the toner without corners is not particularly limited. For example, as described above as a method of controlling the shape factor, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy due to impact force in a gas phase, or a method of dissolving toner It can be obtained by adding it to a solvent that does not contain it and imparting a swirling flow.

Further, in the polymerization toner formed by associating or fusing resin particles, the surface of the fused particles has many irregularities at the step of stopping the fusion, and the surface is not smooth, The toner having no corners can be obtained by appropriately adjusting the conditions such as the temperature, the rotation speed of the stirring blade, and the stirring time. These conditions vary depending on the physical properties of the resin particles, but for example, by setting the glass transition temperature of the resin particles or higher to a higher rotation speed, the surface becomes smooth and toner without corners can be formed.

Further, by adjusting the toner particles of each color in which the proportion of toner particles having no corners is 50 number% or more and the number variation coefficient in the number particle size distribution is 27% or less, the toner particles on the intermediate transfer member are adjusted. The transferability between the toner particles can be made uniform, and a good image can be formed without causing image defects such as dust when transferred to the image forming support.

The toner used in the present invention is composed of toner particles adjusted so that the variation coefficient of the shape coefficient is more than 0% and 16% or less and the number variation coefficient in the number particle size distribution is more than 0% and 27% or less. Preferably.

The toner used in the present invention more preferably has a variation coefficient of shape coefficient of more than 0% and 14% or less and a number variation coefficient of more than 0% and 25% or less.

Here, the "coefficient of variation of the shape factor" of the toner according to the present invention can be calculated from the following formula.

Coefficient of variation (%) = (S ₁ / K) × 100 In the formula, S ₁ represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.

By adjusting the variation coefficient of the shape factor to 16% or less, the voids of the toner layer (powder layer) transferred to the intermediate transfer member are reduced, and the transfer to the image forming support is satisfactory. The transferability can be maintained, and the charge amount distribution can be sharpened to improve the image quality. This effect is further improved when the variation coefficient of the shape factor is 14% or less.

In order to uniformly control the shape factor and the variation coefficient of the shape factor of the toner without extremely lot variation, the resin particles (polymer particles) constituting the toner of the present invention are prepared (polymerized), and the resin In the process of fusing and controlling the shape of the particles, an appropriate process end time may be determined while monitoring the characteristics of the toner particles (colored particles) being formed.

Monitoring means that a measuring device is installed in-line and the process condition is controlled based on the measurement result. That is, in the case of a polymerization toner in which measurement of a shape or the like is incorporated inline, for example, a resin toner is formed by associating or fusing resin particles in an aqueous medium, the shape and the particle size are measured while performing sequential sampling in the steps such as fusing. Is measured, and the reaction is stopped when the desired shape is obtained.

The monitoring method is not particularly limited, but a flow type particle image analyzer FPIA-2000 is used.
(Manufactured by Toa Medical Electronics Co., Ltd.) can be used. This device is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field to constantly monitor and measure the shape and the like, and the reaction is stopped when the desired shape or the like is obtained.

The number particle size distribution and number variation coefficient of the toner used in the present invention are measured with a Coulter counter TA- or Coulter Multisizer (manufactured by Coulter). In the present invention, a Coulter Multisizer was used, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting the particle size distribution and a personal computer were connected and used. The aperture used in the Coulter Multisizer is 100 μm,
The particle size distribution and average particle size were calculated by measuring the volume and number of toner particles of 2 μm or larger. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution. The “number variation coefficient in the number particle size distribution” of the toner is calculated from the following formula.

Number variation coefficient (%) = (S ₂ / D _n ) × 100 In the formula, S ₂ represents the standard deviation in the number particle size distribution, and D _n
Indicates the number average particle diameter (μm).

By adjusting the number variation coefficient to 27% or less, the voids of the toner layer (powder layer) transferred to the intermediate transfer member are reduced, and the transferability at the time of retransfer to the image forming support is reduced. , The charge amount distribution becomes sharp, the transfer efficiency increases, and the image quality improves. Number variation coefficient is 2
If it is adjusted to 5% or less, this effect is further improved.

The method of controlling the number variation coefficient in the toner of the present invention is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of controlling the number of revolutions and separately collecting and preparing toner particles according to the difference in sedimentation speed caused by the difference in toner particle diameter.

Particularly when the toner is produced by the suspension polymerization method, the classification operation is indispensable in order to keep the number variation coefficient in the number particle size distribution at 27% or less. In the suspension polymerization method,
Before the polymerization, it is necessary to disperse the polymerizable monomer into an oil droplet having a desired size as a toner in an aqueous medium. That is, the large oil droplets of the polymerizable monomer are repeatedly mechanically sheared by a homomixer or a homogenizer to reduce the oil droplets to the size of toner particles. In the method of different shearing, the number particle size distribution of the obtained oil droplets becomes wide, and therefore,
The toner obtained by polymerizing this also has a wide particle size distribution. For this reason, classification operation is essential.

The particle size of the toner of the present invention is preferably 3-8 μm in number average particle size. In the case where toner particles are formed by a polymerization method, this particle diameter is used in the toner production method described in detail later, in the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself. Can be controlled by.

When the number average particle diameter is in the range of 3 to 8 μm, the thickness of the toner layer formed on the intermediate transfer member does not become excessive and the transferability is improved. Further, since the transfer efficiency is increased, the halftone image quality is improved, and the image quality of fine lines, dots, etc. is also improved.

The toner according to the present invention is a histogram showing the particle size distribution (the vertical axis is the number basis, and the horizontal axis is the natural logarithm ln).
(D) (D is the toner particle diameter), 0.23 on the horizontal axis
Relative frequency (m ₁ ) of toner particles included in the most frequent class in a histogram showing a number-based particle size distribution divided into a plurality of classes at intervals, and toner particles included in the next most frequent class It is preferable that the toner has a sum (M) with the relative frequency (m ₂ ) of 70% or more with respect to the entire toner.

By adjusting the sum (M) of the relative frequency (m ₁ ) and the relative frequency (m ₂ ) to be 70% or more,
Since the dispersion of the particle size distribution of the toner particles becomes narrow, it is possible to reliably suppress the occurrence of selective development during image formation.

In the histogram showing the particle size distribution based on the number, the natural logarithm ln (D) (D: particle size of each toner particle) is divided into a plurality of classes (0 to 0.23:
0.23-0.46: 0.46-0.69: 0.69-
0.92: 0.92 to 1.15: 1.15 to 1.38:
1.38 to 1.61: 1.61 to 1.84: 1.84 to
2.07: 2.07 to 2.30: 2.30 to 2.53:
2.53 to 2.76 ...), which is a histogram showing a number-based particle size distribution, which is obtained by converting the particle size data of the sample measured by a Coulter Multisizer into I / I according to the following conditions. It is preferable that the data is transferred to the computer via the O unit and is prepared by the particle size distribution analysis program in the computer.

[Measurement Conditions] (1) Aperture: 100 μm (2) Sample Preparation Method: Electrolyte Solution [ISOTON R-1
1 (manufactured by Coulter Scientific Japan)
An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml and stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by subjecting it to an ultrasonic disperser for 1 minute.

The toner used in the present invention comprises (a) a ratio of toner particles having a shape factor of 1.2 to 1.6,
It is possible to clearly distinguish (b) the variation coefficient of the shape coefficient, (c) the ratio of toner particles having no angle, and (d) the variation coefficient of the number in the number particle size distribution, as compared with the conventionally known toner.

The above (a) to the toner relating to the present invention
Regarding the numerical values described in (d), conventionally known numerical values of toner will be described. This value varies depending on the manufacturing method.

(In case of pulverized toner) In the case of conventionally known pulverized toner, the ratio of toner particles having a shape factor of 1.2 to 1.6 is about 60% by number. The variation coefficient of the shape factor of this product is about 20%. Further, in the crushing method, since the particle size is reduced by repeating crushing, the toner particles have many corners, and the ratio of toner particles without corners is 3
0% or less. Therefore, when it is intended to obtain a toner having a rounded shape with a uniform shape without corners, it is necessary to perform the spheroidizing process by heat or the like as described above as a method of controlling the shape factor. Further, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after crushing is performed once, and further the classification operation needs to be repeated in order to reduce the number variation coefficient to 27% or less. There is.

(In the case of the toner by the suspension polymerization method) Since the conventional toner is polymerized in a laminar flow, almost spherical toner particles are obtained. For example, JP-A-56-1307
The toner described in No. 62 has a shape factor of 1.2 to
The ratio of toner particles of 1.6 is about 20% by number, the coefficient of variation of the shape coefficient is about 18%, and the ratio of toner particles without corners is about 85% by number. Further, as described above as a method of controlling the number variation coefficient in the number particle size distribution, mechanical shearing is repeated for large oil droplets of the polymerizable monomer to reduce the oil droplets to a size of toner particles. Therefore, the distribution of the oil droplet diameter becomes wider, and therefore the particle size distribution of the obtained toner is wider, and the number variation coefficient is as large as about 32%, and classification operation is necessary to reduce the number variation coefficient. .

A conventional polymerization toner formed by associating or fusing resin particles is described in, for example, Japanese Patent Laid-Open No.
In the toner described in JP-A-3-186253, the proportion of toner particles having a shape factor of 1.2 to 1.6 is 60% by number.
The coefficient of variation of the shape factor is about 18%, and the ratio of toner particles having no corners is about 44% by number. Further, the particle size distribution of the toner is wide, and the number variation coefficient is 30%, and classification operation is required to reduce the number variation coefficient.

The toner according to the present invention is preferably a toner obtained by polymerizing a polymerizable monomer containing at least a colorant in an aqueous medium, and at least resin particles and a colorant in an aqueous medium. The toner obtained by associating with is preferable. Hereinafter, the method for producing the toner of the present invention will be described in detail.

The toner according to the present invention is obtained by emulsion polymerization of a monomer in a suspension polymerization method or in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added to obtain fine polymer particles (resin). Particles), and thereafter, an organic solvent, an aggregating agent and the like are added to the resin particles to associate them. Here, "association" means fusion of a plurality of the resin particles, and includes the case where the resin particles and other particles (for example, colorant particles) are fused.

As an example of the method for producing the toner according to the present invention, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer. Then, various constituent materials are dissolved or dispersed in the polymerizable monomer by using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an oil droplet having a desired size as a toner in a water-based medium containing a dispersion stabilizer by using a homomixer or a homogenizer. After that, the stirring mechanism is moved to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention.

The "aqueous medium" referred to in the present invention
Means at least 50% by mass of water. In addition, as a method for producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. This method is not particularly limited, but for example, JP-A-5-265252 and JP-A-6-265252.
The methods shown in Nos. 329947 and 9-15904 can be mentioned. That is, a method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant, or a plurality of fine particles composed of a resin and a colorant, in particular, after dispersing these in water with an emulsifier, the critical aggregation concentration At the same time as salting out by adding the aggregating agent above, while gradually growing the particle size while forming fused particles by heat fusion above the glass transition temperature of the polymer itself formed, the target particle size and When that happens, add a large amount of water to stop grain size growth,
The toner of the present invention can be formed by further smoothing the surface of the particles while heating and stirring to control the shape and heating and drying the particles in a fluid state in a water-containing state. Here, a solvent that can be infinitely dissolved in water may be added simultaneously with the coagulant.

The polymerizable monomer used for the resin is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethyl styrene, p-tert-butyl styrene, p
-N-hexyl styrene, pn-octyl styrene,
pn-nonylstyrene, pn-decylstyrene, p
Styrene or styrene derivative such as -n-dodecyl styrene, methyl methacrylate, ethyl methacrylate,
N-butyl methacrylate, isopropyl methacrylate,
Methacrylate ester derivatives such as isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate. , Methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate,
Acrylic ester derivatives such as n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate and phenyl acrylate, olefins such as ethylene, propylene and isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide , Vinyl fluoride, vinylidene fluoride, and other halogen-based vinyls, vinyl propionate, vinyl acetate, vinyl benzoate, and other vinyl esters, vinyl methyl ether, vinyl ethyl ether, and other vinyl ethers, vinyl methyl ketone, vinyl ethyl ketone , Vinyl ketones such as vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone, vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylonitrile, Acrylonitrile, there are acrylic acid or methacrylic acid derivatives such as acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a combination of polymerizable monomers having an ionic dissociative group as the polymerizable monomer constituting the resin. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer, and specifically, acrylic acid, methacrylic acid,
Maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl Methacrylate,
3-chloro-2-acid phosphooxypropyl methacrylate and the like can be mentioned.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate,
It is also possible to use a polyfunctional vinyl such as neopentyl glycol diacrylate to form a resin having a crosslinked structure.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As this oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo-based or diazo-based polymerization initiators such as nitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide. , Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-
Examples include peroxide polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in the side chain. .

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetic acid salts, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate. , Barium sulfate,
Examples thereof include bentonite, silica and alumina. Furthermore, polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzene sulfonate, ethylene oxide adduct, higher alcohol sodium sulfate, and the like which are commonly used as surfactants can be used as the dispersion stabilizer.

As the excellent resin in the present invention, those having a glass transition point of 20 to 90 ° C. are preferable and a softening point of 8 is obtained.
It is preferably 0 to 220 ° C. The glass transition point is measured by a differential calorimetric method, and the softening point can be measured by a Koka type flow tester. Furthermore, these resins have a number average molecular weight (Mn) of 10 as measured by gel permeation chromatography.
00-100,000, 200 in weight average molecular weight (Mw)
It is preferably 0 to 1,000,000. Furthermore, as the molecular weight distribution, Mw / Mn is 1.5 to 100, and particularly 1.8.
The thing of -70 is preferable.

The aggregating agent used when associating the resin particles in the aqueous medium is not particularly limited, but those selected from metal salts are preferably used. Specifically, as monovalent metals such as sodium, potassium, salts of alkali metals such as lithium, as divalent metals such as calcium, alkaline earth metal salts such as magnesium,
Examples of the salt include salts of divalent metals such as manganese and copper, salts of trivalent metals such as iron and aluminum, and specific salts.
Examples thereof include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate and manganese sulfate. These may be used in combination.

It is preferable to add these aggregating agents in a concentration higher than the critical aggregating concentration. This critical coagulation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which coagulation occurs when a coagulant is added. This critical aggregation concentration is
It greatly changes depending on the emulsified component and the dispersant itself. For example, Seizo Okamura et al., "Polymer Chemistry 1"
7, 601 (1960) edited by The Polymer Society of Japan ”and the like, and a detailed critical aggregation concentration can be obtained.
As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is determined as the critical aggregation concentration. You can also ask.

The coagulant of the present invention may be added in an amount equal to or higher than the critical coagulation concentration, preferably 1.2 of the critical coagulation concentration.
It is better to add it at least twice, more preferably at least 1.5 times.

As the "solvent infinitely soluble in water" used together with the aggregating agent, one which does not dissolve the resin to be formed is selected. Specific examples thereof include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol, butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferable.

The amount of the solvent infinitely soluble in water is 1 to 1 with respect to the polymer-containing dispersion liquid to which the coagulant is added.
00% by volume is preferred.

To make the particle shape uniform,
It is preferable to prepare colored particles, and after filtering, fluidize and dry the slurry in which 10% by mass or more of water is present with respect to the particles. At this time, it is particularly preferable that the polymer has a polar group. The reason for this is considered to be that the presence of water has an effect of swelling the polymer having a polar group to some extent, so that the homogenization of the shape is particularly likely to be achieved.

The toner of the present invention contains at least a resin and a colorant, but may contain a releasing agent which is a fixing property improving agent, a charge control agent and the like, if necessary. Further, an external additive composed of inorganic fine particles, organic fine particles or the like may be added to the toner particles containing the resin and the colorant as main components.

As the colorant used in the toner of the present invention, carbon black, a magnetic substance, a dye, a pigment or the like can be optionally used. Examples of the carbon black include channel black, furnace black, acetylene black,
Thermal black, lamp black, etc. are used. Ferromagnetic metals such as iron, nickel, and cobalt as magnetic materials,
Alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys containing no ferromagnetic metals but exhibiting ferromagnetism by heat treatment, such as manganese-copper-
Aluminum, manganese-copper-tin, and other types of alloys called Heusler alloys, chromium dioxide, and the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, ibid 79, ibid 81, ibid 82, ibid 93, ibid 98, ibid 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like can be used, and a mixture thereof can also be used. As the pigment, C.I. I. Pigment Red 5,
48: 1, 53: 1, 57: 1, 122, 1
39, 144, 149, 166, 177, 1
78, ibid. 222, C.I. I. Pigment Orange 31, the same 43, C.I. I. Pigment Yellow 14, Same 17 and Same 9
3, ibid 94, ibid 138, ibid 155, ibid 156, ibid 18
0, 185, C.I. I. Pigment Green 7, C.I.
I. Pigment Blue 15: 3, 60 and the like, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is generally 10 to 200 n.
About m is preferable.

The colorant may be added by adding the polymer particles prepared by an emulsion polymerization method at the stage of aggregating by adding an aggregating agent to color the polymer or at a step of polymerizing a monomer. It is possible to use a method in which a coloring agent is added and polymerized to obtain colored particles. When the colorant is added at the stage of preparing the polymer, it is preferable that the surface is treated with a coupling agent or the like so as not to hinder radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000) or low molecular weight polyethylene as a fixing property improving agent may be added. In addition, an ester wax can be used as a fixing improving material. Examples of the ester wax include carnauba wax, and candelilla wax and microcrystalline wax.

The method of adding the fixability improving agent to the toner is not particularly limited, but for example, a method of salting out / fusing with the resin particles as in the case of the colorant particles, or a method of preparing the resin particles in the monomer. There is also a method of dissolving the fixability improving agent in the above and then polymerizing it to prepare resin particles.

Similarly, various charge control agents are known,
Moreover, the thing which can be disperse | distributed in water can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Examples thereof include secondary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof.

The particles of these charge control agents and fixability improvers have a number average primary particle diameter of 10 to 50 in a dispersed state.
It is preferably about 0 nm.

In the toner used in the present invention, the effect can be more enhanced by adding fine particles such as inorganic fine particles and organic fine particles as an external additive. The reason for this is presumed to be that the embedding and detachment of the external additive can be effectively suppressed, and the effect is remarkable.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania, and alumina. Further, these inorganic fine particles are hydrophobized with a silane coupling agent or a titanium coupling agent. preferable. The degree of hydrophobic treatment is not particularly limited, but methanol wettability (hydrophobicity) of 40 to 95 is preferable. Methanol wettability is an evaluation of wettability with respect to methanol. In this method, 0.2 g of inorganic fine particles to be measured is weighed and added to 50 ml of distilled water placed in a beaker having an internal volume of 200 ml. Methanol is dripped slowly from a buret whose tip is dipped in the liquid, with slow stirring until all the inorganic fine particles become wet. When the amount of methanol required to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following formula.

Hydrophobicity = (a / (a + 50)) × 100 The addition amount of this external additive is 0.1 to 5% in the toner.
It is 0% by mass, preferably 0.5 to 4.0% by mass. Further, various external additives may be used in combination.

A suspension polymerization method toner in which a toner constituent component such as a colorant or the like is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner is subjected to a polymerization reaction. The shape of the toner particles can be controlled by controlling the flow of the medium in the reaction vessel. That is, when a large number of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is made turbulent, and the polymerization proceeds to exist in the aqueous medium in a suspended state. When the oil droplets are gradually polymerized and the oil droplets become soft particles, the particles collide with each other to promote the association of the particles, and particles having an irregular shape can be obtained. Further, in the case of forming substantially spherical toner particles having a shape factor of less than 1.2, the flow of the medium in the reaction vessel is made a laminar flow, and collision of the particles is avoided to obtain substantially spherical particles. By this method,
The toner shape distribution can be controlled within the scope of the present invention.

FIG. 6 is an explanatory view showing a reaction apparatus (stirring apparatus) having a generally used stirrer blade structure of one stage. 2 is a stirrer tank, 3 is a rotary shaft, 4 is a stirrer blade, 9 Is a turbulent flow forming member.

In the suspension polymerization method, a turbulent flow can be formed by using a specific stirring blade, and the shape can be easily controlled. Although the reason for this is not clear, when the configuration of the stirring blade 4 as shown in FIG. 6 is one stage, the flow of the medium formed in the stirring tank 2 is
Only the flow that moves along the wall from the lower part to the upper part.
Therefore, conventionally, turbulent flow is generally formed by arranging the turbulent flow forming member 9 such as the wall surface of the stirring tank 2 to increase the stirring efficiency. However, in such an apparatus configuration, although a turbulent flow is formed in part, it acts rather in the direction in which the fluid flow stagnates due to the presence of the turbulent flow, and as a result, there is less misalignment with respect to the particles. Cannot be controlled.

A reaction apparatus equipped with a stirring blade that can be preferably used in the suspension polymerization method will be described with reference to the drawings.

FIG. 7 and FIG. 8 are a perspective view and a sectional view showing an example of such a reaction apparatus, respectively. Figure 7
In the reactor shown in FIG. 8, a rotating shaft 3 is vertically provided at the center of a vertical cylindrical stirring tank 2 having a jacket 1 for heat exchange mounted on the outer periphery thereof, and the stirring tank 2 is attached to the rotating shaft 3. And a lower stirring blade 40 arranged closer to the bottom surface and a further upper stirring blade 50. The upper stirring blade 50 is arranged at a crossing angle α preceding the lower stirring blade 40 in the rotation direction. In the case of producing the toner of the present invention, the crossing angle α is preferably less than 90 degrees (°). The lower limit of the intersection angle α is not particularly limited, but is preferably about 5 ° or more, and more preferably 10 ° or more.
When three-stage stirring blades are provided, the crossing angle between adjacent stirring blades is preferably less than 90 degrees.

With such a structure, the medium is first stirred by the stirring blades 50 arranged in the upper stage, and a downward flow is formed. Then, the stirring blade 40 arranged in the lower stage accelerates the flow formed by the stirring blade 50 in the upper stage further downward, and the stirring blade 50 itself also forms a downward flow, so that the flow as a whole is reduced. It is estimated to accelerate and proceed. As a result, a basin having a large shear stress formed as a turbulent flow is formed, and it is presumed that the shape of the obtained toner particles can be controlled.

7 and 8, the arrow indicates the direction of rotation, 7 is the upper material charging port, 8 is the lower material charging port, and 9 is the lower material charging port.
Is a turbulent flow forming member for making stirring effective.

Here, the shape of the stirring blade is not particularly limited, but it has a rectangular plate shape, a blade with a cutout, and a central portion having one or more holes, so-called slits. Things etc. can be used. Specific examples of these are shown in FIG. Stirrer blade 5 shown in FIG. 9 (a)
a has no central hole, the stirring blade 5b shown in FIG. 6B has a large central hole 6b in the center, and the stirring blade 5c shown in FIG. 6C has a horizontally long central hole 6c (slit). ), The stirring blade 5d shown in FIG.
There is a (slit). Further, in the case of providing a three-stage stirring blade, even if the middle hole portion formed in the upper stirring blade and the middle hole portion formed in the lower stirring blade are different, they may be the same. It may be.

FIGS. 10 to 14 are perspective views showing specific examples of reactors equipped with stirring blades which can be preferably used. In FIGS. 10 to 14, 1 is a jacket for heat exchange and 2 is a heat exchanger. Is a stirring tank, 3 is a rotating shaft, 7 is an upper material charging port, 8 is a lower material charging port, and 9 is a turbulent flow forming member.

In the reactor shown in FIG. 10, the stirring blade 4
1, the bent portion 411 is formed, and the stirring blade 51 is provided with fins (projections) 511. When the stirring blade has a bent portion, the bending angle is preferably 5 to 45 °.

Stirring blade 4 constituting the reactor shown in FIG.
The slit 421 is formed in the second member 2, and the bent portion 422 and the fin 423 are formed in the slit 2. The stirring blade 52 that constitutes the reaction apparatus has the same shape as the stirring blade 50 that configures the reaction apparatus shown in FIG. 7.

Stirring blade 4 constituting the reactor shown in FIG.
The bent portion 431 and the fin 432 are formed on the third portion 3. In addition, the stirring blade 53 which comprises the said reaction apparatus
Has the same shape as the stirring blade 50 that constitutes the reactor shown in FIG.

Stirring blade 4 constituting the reactor shown in FIG.
Bent portions 441 and fins 442 are formed on the surface 4. Further, the stirring blade 54 constituting the reaction apparatus has a central hole portion 541 formed at the center.

The reaction apparatus shown in FIG. 14 includes a stirring blade 45.
(Lower stage), a stirring blade 55 (middle stage), and a stirring blade 65 having a three-stage structure are provided.

The stirring blade having the bent portion and the projections (fins) on the upper portion or the lower portion effectively generates turbulent flow.

The gap between the upper and lower stirring blades having the above structure is not particularly limited, but it is preferable that there is at least a gap between the stirring blades. The reason for this is not clear, but it is considered that the stirring efficiency is improved because the flow of the medium is formed through the gap. However, the gap has a width of 0.5 to 50%, preferably a width of 1 to 30% with respect to the liquid surface height in a stationary state.

Further, the size of the stirring blades is not particularly limited, but the total height of all stirring blades is 50 to 100%, preferably 60 to 95% of the liquid level height in the stationary state. Is.

FIG. 15 shows an example of the reaction apparatus used when forming a laminar flow in the suspension polymerization method. This reaction device is characterized in that a turbulent flow forming member (obstacle plate or other obstacle) is not provided.

The stirring blades 46 and 56 constituting the reaction apparatus shown in FIG. 15 have the same shape and crossing angle α as the stirring blades 40 and 50 constituting the reaction apparatus shown in FIG. 7, respectively. is doing. In addition, in FIG.
1 is a jacket for heat exchange, 2 is a stirring tank, 3 is a rotating shaft,
Reference numeral 7 is an upper material charging port, and 8 is a lower material charging port. The reactor used when forming the laminar flow is not limited to that shown in FIG.

The shape of the stirring blades constituting such a reaction apparatus is not particularly limited as long as it does not cause turbulence, but a rectangular plate-shaped one formed by a continuous surface is preferable, It may have a curved surface.

On the other hand, in the case of a polymerized toner in which resin particles are associated or fused with each other in an aqueous medium, the flow and temperature distribution of the medium in the reaction vessel at the fusion stage are controlled to further improve the shape after fusion. By controlling the heating temperature, stirring rotation number, and time in the control step, the shape distribution and shape of the entire toner can be arbitrarily changed.

That is, in the case of a polymerized toner in which resin particles are associated or fused, the flow in the reaction device is a laminar flow,
By using a stirring blade and a stirring tank that can make the internal temperature distribution uniform, by controlling the temperature, rotation speed, and time in the fusion process and shape control process, the desired shape factor and uniform A toner having a shape distribution can be formed. The reason for this is that when fusion is performed in a laminar flow-forming place, strong stress is not applied to particles (association or agglomerated particles) in which aggregation and fusion are progressing, and in a laminar flow in which the flow is accelerated, It is presumed that, as a result of the uniform temperature distribution in the stirring tank, the shape distribution of the fused particles becomes uniform. Furthermore, heating in the subsequent shape control process,
By stirring, the fused particles gradually become spherical and the shape of the toner particles can be arbitrarily controlled.

As the stirring blade and stirring tank used in the production of the polymerization toner for associating or fusing the resin particles, the same stirring blades and stirring tanks as those for forming the laminar flow in the suspension polymerization method can be used. For example, the one shown in FIG. 15 can be used. The feature of the invention is that no obstacles such as baffles that form turbulence are provided in the stirring tank. Regarding the structure of the stirring blade, similar to the stirring blade used in the suspension polymerization method described above, the upper stirring blade is arranged with a crossing angle α preceding the lower stirring blade in the rotational direction. Further, it is preferable to have a multi-stage structure.

The shape of the stirring blade may be the same as that used for forming a laminar flow in the suspension polymerization method described above, and is not particularly limited as long as it does not cause turbulent flow. The one formed by a continuous surface such as the rectangular plate-like one shown in () is preferable, and may have a curved surface.

As the toner used in the present invention, a non-magnetic toner is used alone when it is used as a one-component magnetic toner containing a magnetic material, when it is used as a two-component developer by mixing with a so-called carrier. In the present invention, it is preferably used as a two-component developer mixed with a carrier.

The developing method that can use the toner used in the present invention is not particularly limited.

The volume average particle diameter of the carrier that can be used as the two-component developer is preferably 15 to 100 μm, more preferably 25 to 60 μm. The volume average particle size of the carrier is typically measured by a laser diffraction type particle size distribution measuring device “HELOS (HELO) equipped with a wet disperser.
S) "(manufactured by SYMPATEC).

The carrier is preferably one further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in the resin. The resin composition for coating is not particularly limited, but, for example, an olefin resin, a styrene resin, a styrene / acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used. The resin for forming the resin-dispersed carrier is not particularly limited, and known ones can be used, and for example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin, etc. can be used. it can.

[0231]

EXAMPLES Next, the aspects of the present invention will be specifically described.
The configuration of the present invention is not limited to this. In addition, "part" in a sentence represents a "mass part."

<< Dispersion Example >> The intermediate layer dispersions of Examples and Comparative Examples were prepared as follows.

(Preparation of Intermediate Layer Dispersion Liquid 1) Polyamide resin CM8000 (manufactured by Toray) 1 part Titanium oxide SMT500SAS (manufactured by Teika; surface treatment is silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 3. 0 parts Methanol 10 parts Dispersion was carried out batchwise with a sand mill as a disperser for a dispersion time of 10 hours, to prepare an intermediate layer dispersion liquid 1.

(Preparation of Intermediate Layer Dispersion Liquids 2 to 7) Intermediate layer dispersion liquid 1 was prepared in the same manner as in the intermediate layer dispersion liquid 1, except that titanium oxide and its surface treatment, particle size, and solvent were changed as shown in Table 1. Liquids 2 to 7 were prepared.

(Preparation of Intermediate Layer Dispersion Liquid 8) 1 part of polyamide resin CM8000 (manufactured by Toray Industries, Inc.) was added to 7 parts of methanol and 1-
An intermediate layer dispersion liquid 8 (comparative example) was prepared by adding 3 parts of propanol to a mixed solvent and dissolving.

(Preparation of Intermediate Layer Dispersion 9) Intermediate Layer Dispersion 9 (Comparative Example) was prepared in the same manner as Intermediate Layer Dispersion 1 except that silica (Aerosil R805, Tegusa Co.) was dispersed in place of titanium oxide. It was made.

<< Photoreceptor Example >> Photoreceptor 1 The above-mentioned intermediate layer dispersion coating liquid 1 was applied onto a cleaned cylindrical aluminum substrate by a dip coating method to form an intermediate layer having a dry film thickness of 2 μm. In the present invention, the drying condition is low temperature drying and is controlled slowly so that Benard cells are stably generated. That is, first, after drying at 60 ° C. for 10 minutes, 40
Further drying was carried out at 30 ° C. for 30 minutes.

The volume resistance is 2 × 10 ¹⁰ Ω.
It was cm. <Intermediate layer (UCL) coating liquid> The intermediate layer dispersion liquid 1 was diluted twice with the same mixed solvent, and allowed to stand overnight and then filtered (filter; Rigimesh filter manufactured by Nippon Pall Ltd. nominal filtration accuracy: 5 μm, pressure; 0). 0.5 × 9.8 N / cm ² ).

The following coating solutions were mixed and dispersed using a sand mill to prepare a charge generation layer coating solution. This coating solution is applied by a dip coating method to form a dry film thickness of 0.3 μm on the intermediate layer.
m charge generating layer was formed.

<Charge Generating Layer (CGL) Coating Liquid> Y-type oxytitanyl phthalocyanine (Cu-Kα characteristic X-rays has a maximum peak angle of 2θ of 27.3 at 27.3) 20 g Polyvinyl butyral (# 6000-C, electric Chemical Industry Co., Ltd.) 10 g t-butyl acetate 700 g 4-methoxy-4-methyl-2-pentanone 300 g The following coating solutions were 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 thickness of 24 μm.

<Charge Transport Layer (CTL) Coating Liquid> Charge Transport Agent ([4- (2,2-diphenylvinyl) phenyl] -di-p-trilylamine) 75 g Polycarbonate Resin “Upilon-Z300” (Mitsubishi Gas Chemical Company) Manufacture) 100 g methylene chloride 750 g Photoreceptor 2-9 Instead of the intermediate layer dispersion 1 used in the photoconductor 1, the intermediate layer dispersions 2 to 9 (8 is not a dispersion) are used, respectively. In the same manner as the preparation of the liquid 1, the photoconductors 2 to 9 were prepared as shown in Table 1. The drying conditions are the same as those for the photoconductor 1.

The volume resistance of these intermediate layers was 0.5 × 10 ^{10 to} 6 × 10 ¹⁰ Ω · cm under the above measurement conditions.

Photoconductor 10 A photoconductor 10 was prepared in the same manner as the photoconductor 1 except that a cylindrical alumite substrate subjected to anodizing and sealing treatment was used as the substrate. The drying conditions are the same as those for the photoconductor 1.

When the surface of the intermediate layer was observed with a scanning electron microscope at a magnification of 200, a concave portion having a shape as shown in FIG. 16, that is, a large number of polygons was formed in the front, rear, left and right. It was confirmed. The length of the longest part was 20 to 200 μm.

The contents of each of the above intermediate layers are shown in Table 1, including the evaluation of occurrence of Benard cells.

Evaluation of Intermediate Layer Further, the surface of the intermediate layer was observed with a scanning electron microscope at a magnification of 200, and a concave portion having a shape as shown in FIG.
That is, it was confirmed that a large number of polygons were formed in the front, rear, left and right (Benard cell structure), and the following judgment was made. 16A shows a hexagonal concave portion, and b shows a spot-shaped concave portion.

⊚: Polygonal recesses with the longest length of 20 to 200 μm are formed in 50% or more of the intermediate layer surface layer. ○: Polygonal recesses with the longest length of 20 to 200 μm are 10 to 10 of the intermediate layer surface layer. 49% generation ×: Polygonal recesses with a maximum length of 20 to 200 μm were less than 10% of the intermediate surface layer XX: Polygonal recesses with a maximum length of 20 to 200 μm were generated on the intermediate surface layer at all Without it, Table 1 shows the photoconductor formulation and the results.

[0248]

[Table 1]

Next, a toner for image evaluation according to the present invention was prepared as follows. (Bk Toner Production Method 1: Emulsion Polymerization Association Method) 0.90 kg of sodium n-dodecyl sulfate and 10.0 liter of pure water were put and dissolved by stirring. To this solution, 1.20 kg of Regal 330R (Carbon Black manufactured by Cabot Corporation) was gradually added, and after well stirring for 1 hour, the mixture was continuously dispersed for 20 hours using a sand grinder (medium type disperser). This is designated as "colorant dispersion liquid 1". A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 liters of ion-exchanged water is referred to as "anionic surfactant solution A".

A solution consisting of 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct and 4.0 liters of ion-exchanged water was designated as "nonionic surfactant solution B".
And 238 g of potassium persulfate was added to ion-exchanged water 12.
The solution dissolved in 0 liter is designated as "initiator solution C".

In a GL (glass lining) reactor having a volume of 100 liter, equipped with a temperature sensor, a cooling tube, and a nitrogen introducing device, a WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 12)
3.4 nm (0 nm / solid content concentration = 29.9%), the total amount of “anionic surfactant solution A” and the total amount of “nonionic surfactant solution B” were added, and stirring was started. Next, 44.0 liters of ion-exchanged water was added.

When heating was started and the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ° C ± 1 ° C, styrene 1
2.1 kg, n-butyl acrylate 2.70 kg, methacrylic acid 1.14 kg, and t-dodecyl mercaptan 55.
A solution consisting of 0 g was added dropwise. After the dropping was completed, the liquid temperature was raised to 80 ° C. ± 1 ° C., and the mixture was heated and stirred for 6 hours. Then, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and filtration was performed with a pole filter to obtain a latex.
This is designated as "latex-A".

The resin particles in Latex-A had a glass transition temperature of 58 ° C., a softening point of 119 ° C., a molecular weight distribution of weight average molecular weight = 135,000, and a weight average particle diameter of 11 ° C.
It was 5 nm.

A solution prepared by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 liters of ion-exchanged pure water is referred to as "anionic surfactant solution D".

A solution prepared by dissolving 0.014 kg of a 10-mol addition product of nonylphenol polyethylene oxide in 4.0 liters of ion-exchanged water was designated as "nonionic surfactant solution E".

200 g of potassium persulfate (manufactured by Kanto Chemical Co., Inc.)
Is referred to as "initiator solution F".

In a 100 liter GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device and a comb-shaped baffle, W
AX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 120 nm / solid content concentration 29.9%) 3.41 kg, “anionic surfactant solution D” total amount and “nonionic surfactant solution E” total amount Was added and stirring was started.

Next, 44.0 liters of ion-exchanged water was added. Heating was started, and when the liquid temperature reached 70 ° C., “initiator solution F” was added. Then, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid and 9.0 g of t-dodecyl mercaptan was added dropwise. After the dropping was completed, the liquid temperature was controlled at 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature was cooled to 40 ° C. or lower and stirring was stopped. It is filtered with a pole filter, and this filtrate is designated as "latex-B".

The resin particles in Latex-B had a glass transition temperature of 59 ° C., a softening point of 133 ° C., a molecular weight distribution of weight average molecular weight = 245,000 and a weight average particle diameter of 11 ° C.
It was 0 nm.

Sodium chloride as a salting-out agent 5.36k
A solution prepared by dissolving g in 20.0 liters of ion-exchanged water is referred to as “sodium chloride solution G”.

A solution prepared by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 liter of ion-exchanged water is referred to as "nonionic surfactant solution H".

In a 100-liter SUS reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introduction device, and a particle size and shape monitoring device (reactor having the configuration shown in FIG. 16, crossing angle α is 25 °), Latex-A =
20.0 kg, latex-B = 5.2 kg, colorant dispersion 1 = 0.4 kg, and ion-exchanged water 20.0 kg were added and stirred. Then, the mixture was heated to 40 ° C., sodium chloride solution G, isopropanol (Kanto Chemical Co., Ltd.) 6.00 k
g and nonionic surfactant solution H were added in this order. Then, after leaving it for 10 minutes, the temperature rise is started and the liquid temperature becomes 8
The temperature was raised to 5 ° C. in 60 minutes, and heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours to grow the particle size while salting out / fusing.
Next, 2.1 liters of pure water was added to stop grain size growth.

A 5 liter reaction vessel equipped with a temperature sensor, cooling tube, particle size and shape monitoring device (see FIG. 1).
5 kg of the fused particle dispersion liquid prepared above was placed in a reactor having a structure shown in FIG. 5 and a crossing angle α of 20 °, and heated at a liquid temperature of 85 ° C. ± 2 ° C. for 0.5 to 15 hours. The shape was controlled by stirring. Then, it cooled to 40 degrees C or less, and stopped stirring. Next, using a centrifuge, classification is performed in the liquid by a centrifugal sedimentation method, and the mixture is filtered through a sieve having an opening of 45 μm to obtain the filtrate as an association liquid. Then, using a Nutsche filter, wet cake-like non-spherical particles were collected from the association liquid by filtration. Then, it was washed with ion-exchanged water. The intake temperature of these non-spherical particles is 60 ° C using a flash jet dryer.
And then dried at a temperature of 60 ° C. using a fluidized bed dryer. To 100 parts by mass of the obtained colored particles,
1 part by mass of silica fine particles was externally mixed with a Henschel mixer to obtain a black toner by an emulsion polymerization association method.

In the monitoring of the salting-out / fusion step and the shape control step, the stirring speed and the heating time were controlled to control the shape and the coefficient of variation of the shape coefficient, and further, the particle size was classified by liquid classification. And a black toner (Bk) composed of toner particles having specific shape characteristics and particle size distribution characteristics by arbitrarily adjusting the coefficient of variation of the particle size distribution.
1-1 and 1-2 were obtained.

(Y Toner Production Method 1: Emulsion Polymerization Association Method) B
In the toner manufacturing method 1, the colorant is C.I. I. Pigment Yellow 180 1.0
Yellow toner (Y) 1-1 to 1-1 having specific shape characteristics and particle size distribution characteristics in the same manner except that 5 kg was used.
-2 was obtained.

(M Toner Production Method 1: Emulsion Polymerization Association Method) B
k In the same manner as in Toner Production Method 1, except that 1.20 kg of a quinacridone-based magenta pigment (CI Pigment Red 122) is used in place of carbon black as a colorant, it has specific shape characteristics and particle size distribution characteristics. Magenta toner (M) 1-1 to 1-2 composed of toner particles
Got

(C Toner Production Method 1: Emulsion Polymerization Association Method) B
k In the same manner as in Toner Production Method 1, except that 0.60 kg of a phthalocyanine-based cyan pigment (CI Pigment Blue 15: 3) was used in place of carbon black as a colorant, specific shape characteristics and particle size distribution characteristics were obtained. Cyan toner (C) 1-1 to 1-2 composed of toner particles having
Got

(Bk Toner Production Method 2: Suspension Polymerization Method) Styrene = 165 g, n-butyl acrylate = 35 g, carbon black = 10 g, di-t-butyl salicylate metal compound = 2 g, styrene-methacrylic acid copolymer = 8
6 g of paraffin wax (mp = 70 ° C.) = 20 g
Heated to 0 ℃, TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.)
Was uniformly dissolved and dispersed at 12000 rpm. To this, 2,2'-azobis (2,4-valeronitrile) = 10 g as a polymerization initiator was added and dissolved to prepare a polymerizable monomer composition. Then, to 710 g of deionized water, 0.
450 g of a 1 M sodium phosphate aqueous solution was added, and 68 g of 1.0 M calcium chloride was gradually added while stirring at 13000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed. The above polymerizable monomer composition was added to this suspension and the mixture was mixed with a TK homomixer to 1000
The polymerizable monomer composition was granulated by stirring at 0 rpm for 20 minutes. Then, using a reactor having a structure as shown in FIG. 7 (crossing angle α is 45 °) at 75 to 95 ° C. for 5 to 15
Reacted for hours. Tricalcium phosphate was dissolved and removed with hydrochloric acid, and then classified in the liquid by a centrifugal sedimentation method using a centrifuge, followed by filtration, washing and drying. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by a suspension polymerization method.

By monitoring at the time of the polymerization and controlling the liquid temperature, the number of revolutions of stirring, and the heating time, the variation coefficient of the shape and the shape factor is controlled, and further, the variation in the particle size and the particle size distribution is determined by the classification in the liquid. The coefficient was arbitrarily adjusted to obtain black toners (Bk) 2-1 and 2-2 composed of toner particles having specific shape characteristics and particle size distribution characteristics.

(Y Toner Production Method 2: Suspension Polymerization Method) In the Bk toner production method 2, the colorant is C.I. instead of carbon black. I. Pigment Yellow 180 1.05k
g yellow toner (Y) 2-1 to 2-2 having specific shape characteristics and particle size distribution characteristics
Got

(M Toner Production Method 2: Suspension Polymerization Method) In Bk Toner Production Method 2, 1.20 kg of a quinacridone-based magenta pigment (CI Pigment Red 122) was used in place of carbon black as a colorant. In the same manner, magenta toners (M) 2-1 to 2-2 composed of toner particles having specific shape characteristics and particle size distribution characteristics were obtained.

(C Toner Production Method 2: Suspension Polymerization Method) In Bk Toner Production Method 2, 0.60 kg of a phthalocyanine cyan pigment (CI Pigment Blue 15: 3) was used in place of carbon black as the colorant. In the same manner as above, cyan toners (C) 2-1 to 2-2 composed of toner particles having specific shape characteristics and particle size distribution characteristics were obtained.

(Bk Toner Production Method 3: Grinding Method) A toner raw material consisting of 100 kg of styrene-n-butyl acrylate copolymer resin, 10 kg of carbon black and 4 parts by weight of polypropylene was premixed by a Henschel mixer, and then mixed in a twin-screw extruder. Melt kneading, crushing roughly with a hammer mill, crushing with a jet crusher, and dispersing the obtained powder into the hot air stream of a spray dryer (200-30
Particles whose shape was adjusted at 0 ° C. for 0.05 seconds were obtained. The particles were repeatedly classified by an air classifier until the desired particle size distribution was obtained. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed by a Henschel mixer to obtain a toner by a pulverization method.

In this way, the black toner (Bk) composed of toner particles having specific shape characteristics and particle size distribution characteristics, in which the variation coefficient of the shape and shape coefficient is controlled and the variation coefficient of the particle size and particle size distribution is adjusted, ) 3-1 to 3-2 were obtained.

(Y Toner Manufacturing Method 3: Grinding Method) In the Bk toner manufacturing method 3, the colorant is C.I. instead of carbon black. I. Pigment Yellow 180 was used in the same manner except that 1.05 kg of Pigment Yellow 180 was used to obtain yellow toners (Y) 3-1 to 3-2 having specific shape characteristics and particle size distribution characteristics.

(M Toner Production Method 3: Grinding Method) The same as in Bk Toner Production Method 3 except that 1.20 kg of a quinacridone magenta pigment (CI Pigment Red 122) was used in place of carbon black as the colorant. And then
Magenta toners (M) 3-1 to 3-2 composed of toner particles having specific shape characteristics and particle size distribution characteristics were obtained.

(C Toner Production Method 3: Grinding Method) In Bk toner production method 3, 0.60 kg of a phthalocyanine cyan pigment (CI Pigment Blue 15: 3) was used in place of carbon black as the colorant. In the same manner, cyan toner (C) 3-1 to 3-2 composed of toner particles having specific shape characteristics and particle size distribution characteristics was obtained.

Table 2 below shows the shape characteristics of the toner described above.

[0279]

[Table 2]

A ferrite carrier coated with a silicone resin and having a volume average particle size of 60 μm was mixed with each of the above toners to prepare a developer having a toner concentration of 6%. << Evaluation >> Y, M, C, K image formation composed of the toner (developer) shown in Table 2 and the photoconductors shown in Table 1 (four photoconductors with the same formulation were used in Examples and Comparative Examples). It is mounted on the digital copying machine shown in FIG. 1 having a unit, and an A4 image having a white background portion, a solid black portion, and a solid image portion of red, green, and blue, and a character image portion in an original image is stored at 30 ° C. and 80%. Under RH environment, printing rate is 1 using A4 paper until the photosensitive layer thickness becomes 15 μm due to abrasion.
Performing 0% actual copying, the photosensitive layer thickness of the photoconductor is 15μ
Fog, sharpness, image unevenness, black spots, etc. of the copied image when the m was m were visually evaluated according to the following evaluation criteria.

The results are shown in Table 3. Process conditions for a digital copying machine having an intermediate transfer member Charging means: Scorotron charger Image exposing means: Semiconductor laser developing means: Two-component contact reversal development cleaning condition in which a photoreceptor and a developer come into contact: Hardness 70 ° to the photoreceptor A cleaning blade having a rebound resilience of 34%, a thickness of 2 (mm) and a free length of 7 mm was brought into contact with the counter by a weight load method so that the linear pressure was 20 (g / cm) in the counter direction.

(1) Image Evaluation Crack Test The surface of the sample coated up to the intermediate layer was observed to see if any cracks occurred.

Adhesion Test The surface and edge of the photoconductor actually photographed until the thickness of the photosensitive layer became 15 μm was observed, and the presence or absence of peeling of the photosensitive layer from the edge was checked.

For the density of the fog-copy image, the absolute reflection density was measured using RD-918 manufactured by Macbeth. When the increase in residual potential is large, the image density is low, when the decrease in charging potential is large, fog tends to occur, and when the uniformity of charging potential is low, image unevenness tends to be large.

Sharpness The sharpness of the copy image was visually determined by the number of fine lines per mm that can be discriminated in the copy image of the fifth generation.

With respect to the black spot copy image, it was judged by the number of black spots having a major axis of 0.4 mm or more per A4 paper. The major axis of the black spot was measured with a microscope equipped with a video printer.

The judgment criteria for each evaluation are as follows. The results obtained are shown in Table 3. Crack ◎ ... No practical problems.

◯: A crack that appears slightly in the image is barely acceptable for practical use. ×: Not practical

Adhesiveness ◎ ・ ・ ・ No practical problems.

[0290] ○: Practical is possible because there is a slight peeling on a part of the edge. ×: Peeling is applied to the image part, which is not practical.

Fog: Judgment based on solid white image density A: 0.005 or less (good).

◯: Greater than 0.005 and less than 0.01 (a level that causes no practical problem). X: 0.01 or more (there is a problem in practical use).

Sharpness: Judged by thin line image ◎ ... 8 pieces / mm or more (good).

Good: 6 lines / mm or more and 7 lines / mm or less (at a practically acceptable level). × ... 5 lines / mm or less (there is a problem in practical use).

Image unevenness: density difference of halftone image (Δ
Judgment by HD = maximum density-minimum density ◎ ... 0.05 or less (good).

◯: Greater than 0.05 and less than 0.1 (at a level where there is no practical problem). X: 0.1 or more (there is a problem in practical use).

Black spots ⋅ ····························· s 0.4 mm or more black spots: all copied images are 3 pieces / A4 or less (good).

∙: Black spot frequency of 0.4 mm or more: 4 or more / A4 or more, 19 or less / A4 or less occurred at one or more sheets (a level at which there is no practical problem).

Frequency of black dots of 0.4 mm or more: 20
One piece or more per piece / A4 or more (problems in practical use).

Image regrowth The protruding length of each color was measured for the line width of the line image corresponding to the image signal of 2 dot lines in which magenta and cyan are overlapped.

[0301] A: Less than 70 μm (good). A: 70 to less than 100 μm (no problem in practical use).

Δ ... 100 to less than 150 μm (not practically strict). × ... 150 μm or more (unsuitable).

[0303]

[Table 3]

[0304]

According to the present invention, a tandem type electrophotographic image forming apparatus, an image forming method therefor, and an electronic image forming apparatus which are stable in image quality even when used for a long time in various environments and in which image deterioration does not easily occur. A process cartridge used in a photographic image forming apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of an electrophotographic image forming apparatus of the present invention.

FIG. 2 is a cross-sectional configuration diagram of an image forming unit of the electrophotographic image forming apparatus of the present invention.

FIG. 3 is a cross-sectional configuration diagram showing another example of the image forming unit of the electrophotographic image forming apparatus of the present invention.

FIG. 4 is a cross-sectional configuration diagram of another electrophotographic image forming apparatus of the present invention.

FIG. 5A is an explanatory view showing a projection view of “toner particles without corners”, and FIGS. 5B and 5C are explanatory views showing projection images of toner particles having corners, respectively.

FIG. 6 is an explanatory view showing a reactor having a single stage of stirring blades.

FIG. 7 is a perspective view showing an example of a reactor equipped with a stirring blade that can be preferably used.

8 is a cross-sectional view of the reaction device shown in FIG.

FIG. 9 is a schematic view showing a specific example of the shape of a stirring blade.

FIG. 10 is a perspective view showing a specific example including a stirring blade that can be preferably used.

FIG. 11 is a perspective view showing a specific example including a stirring blade that can be preferably used.

FIG. 12 is a perspective view showing a specific example including a stirring blade that can be preferably used.

FIG. 13 is a perspective view showing a specific example including a stirring blade that can be preferably used.

FIG. 14 is a perspective view showing a specific example including a stirring blade that can be preferably used.

FIG. 15 is a perspective view showing an example of a reaction device used for forming a laminar flow.

FIG. 16 is a partially enlarged plan view of a Benard cell of the intermediate layer of the photoconductor used in the present invention.

[Explanation of symbols]

1 Heat Exchange Jacket 2 Stirring Tank 3 Rotating Shaft 4 Stirring Blades 40, 41, 42, 43, 44, 45, 46 Stirring Blades 411, 422, 431, 441, 451 Bent Parts 50, 51, 52, 53, 54, 56, 65 Stirring blade 511 located in the upper stage Fin 541 Medium hole 55 Stirring blade 5a, 5b, 5c, 5d located in the middle stage Stirring blade 6b, 6c, 6d Medium hole α Crossing angle 10 Transfer body ( Transfer means) 20Y, 20M, 20C, 20K Image forming units 21Y, 21M, 21C, 21K Photoreceptor drums (image forming bodies) 22Y, 22M, 22C, 22K Charging means 23Y, 23M, 23C, 23K Exposure means 24Y, 24M, 24C, 24K Developing means 25Y, 25M, 25C, 25K Cleaning means 26Y, 26M, 26C, 26K Frame bodies 27Y, 27M, 2 7C, 27K Moving member a Recessed portion b corresponding to the drawing line shape such as a hexagonal shape b Spot-shaped recess

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) G03G 9/08 384 (72) Inventor Shinichi Hamaguchi 1st Sakura-cho, Hino-shi, Tokyo Konica Stock Company In-house F-term ( Reference) 2H005 AA01 AA21 AB06 CA04 EA05 EA10 2H030 AA07 AB02 BB71 2H068 AA43 AA45 AA48 BA58 BB28 CA06 CA29 CA33 CA60 FA27 FB11

Claims (24)

[Claims] 1. A photoreceptor having a conductive substrate and a photosensitive layer, and an intermediate layer between the conductive substrate and the photosensitive layer, and a charging unit for imparting a charge to the surface of the photoreceptor. And an image exposure unit that irradiates the charged area of the photoconductor with light.
Developing means for forming an electrostatic latent image on the surface of the photoconductor by the charging means and the image exposing means and for forming a colored toner image corresponding to the electrostatic latent image on the surface of the photoconductor using toner. A plurality of image forming units including a transfer unit that transfers the toner image formed on the photosensitive member to the transfer target member, and a cleaning unit that removes the residual toner on the surface of the photosensitive member. An electrophotographic image forming apparatus using a toner whose color is changed for each unit, wherein the intermediate layer is an insulating layer containing N-type semiconductor particles and a binder and having a Benard cell structure. . 2. The electrophotographic image forming apparatus according to claim 1, wherein the insulating layer has a film thickness of 0.2 to 15 μm. 3. The electrophotographic image forming apparatus according to claim 1, wherein the N-type semiconductor particles have a number average primary particle diameter of 10 to 200 nm. 4. The electrophotographic image forming apparatus according to claim 1, wherein the N-type semiconductor particles are metal oxides. 5. The electrophotographic image forming apparatus according to claim 4, wherein the metal oxide is titanium oxide particles. 6. The titanium oxide particles are surface-treated with silica and / or alumina.
The electrophotographic image forming apparatus according to claim 5, further comprising a surface treatment with a reactive organosilicon compound. 7. The titanium oxide particles are subjected to a surface treatment a plurality of times, and the final surface treatment is a surface treatment with a reactive organosilicon compound.
The electrophotographic image forming apparatus described in 1. 8. The surface treatment of at least one of the plurality of surface treatments of the titanium oxide particles is a surface treatment of one or more compounds selected from alumina, silica and zirconia. 7. The electrophotographic image forming apparatus described in 7. 9. The electrophotographic image forming apparatus according to claim 6, wherein the reactive organosilicon compound is methylhydrogenpolysiloxane. 10. The electrophotographic image forming apparatus according to claim 6, wherein the reactive organosilicon compound is represented by the following general formula (1). General formula (1) R-Si- (X) ₃ (In the formula, R represents an alkyl group, an aryl group, X represents a methoxy group, an ethoxy group, or a halogen atom. Good too.) 11. The R in the general formula (1) is an alkyl group having 4 to 8 carbon atoms.
The electrophotographic image forming apparatus described in 1. 12. The electrophotographic image forming apparatus according to claim 5, wherein the titanium oxide particles are surface-treated with an organic silicon compound having a fluorine atom. 13. The electrophotographic image forming apparatus according to claim 1, wherein the binder is a polyamide resin. 14. The electronic device according to claim 1, wherein an image is formed by using a toner having a variation coefficient of shape coefficient of 16% or less and a variation coefficient of number of 27% or less. Photo image forming apparatus. 15. The electrophotography according to claim 1, wherein 65% or more and less than 100% by number of the toner is a toner having a shape factor of 1.0 to 1.6. Image forming apparatus. 16. The electrophotographic photograph according to claim 1, wherein 65% or more and less than 100% by number of the toner is a toner having a shape factor of 1.2 to 1.6. Image forming apparatus. 17. The electrophotographic image forming apparatus according to claim 1, wherein 50% by number or more and less than 100% by number of the toner is a toner having no corners. 18. The number average particle diameter of the toner is 3 to 8 μm.
m is any one of Claims 1-17 characterized by the above-mentioned.
An electrophotographic image forming apparatus according to the item 1. 19. The toner is a histogram showing a particle size distribution (the frequency is based on the number on the vertical axis, and the natural logarithm is on the horizontal axis).
n (D) (D is the toner particle diameter), the horizontal axis is 0.2
Relative frequency (m1) of toner particles included in the most frequent class in a histogram showing a number-based particle size distribution divided into a plurality of classes at three intervals, and toner included in the next most frequent class. The electrophotographic image forming apparatus according to any one of claims 1 to 18, wherein the sum (M) of the particles and the relative frequency (m2) is 70% or more with respect to the entire particles. 20. The electron according to claim 1, wherein the toner is obtained by polymerizing a polymerizable monomer containing at least a colorant in an aqueous solvent. Photo image forming apparatus. 21. The electrophotographic image forming apparatus according to claim 1, wherein the toner is obtained by association in an aqueous solvent in which at least resin particles and a colorant are present. apparatus. 22. The electrophotographic image forming apparatus according to claim 1, wherein the toner is made of styrene-acrylate resin or styrene-methacrylate resin. 23. An image forming method using the electrophotographic image forming apparatus according to claim 1, wherein a transfer process of the transfer means of each of the image forming units is sequentially performed on the recording material. 24. The process cartridge for an electrophotographic image forming apparatus according to claim 1, further comprising a conductive base and a photosensitive layer, wherein the conductive base and A photoreceptor having an intermediate layer between it and a photosensitive layer, a charging means for applying an electric charge to the surface of the photoreceptor, an image exposing means for irradiating the charged area of the photoreceptor with light, the charging means and the image exposing means. A developing unit for forming an electrostatic latent image on the surface of the photoconductor and a colored toner image corresponding to the electrostatic latent image by using toner on the surface of the photoconductor, formed on the photoconductor. At least one of a transfer means for transferring the toner image to the transfer body, a separation means for separating the transfer body from the photoreceptor or the transfer means, and a cleaning means for removing the residual toner on the surface of the photoreceptor. With Process cartridge.