JP2005215592A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem; with respect to an image forming apparatus using a-Si photoreceptors, when a tandem type full color copying machine is loaded with photoreceptors, surface potential (charge potential) on the photoreceptors cannot be obtained to a satisfactory extent, whereby image density is not obtained to a satisfactory extent. <P>SOLUTION: In a tandem type image forming method, a-Si photoreceptors have a diameter (ϕ) of 20-80 mm, a two-component developing method with a surface potential of 300-450 V and an SD gap of 350-800 μm is adopted, each developing sleeve has a peripheral speed 1.1-4.0 times that of each photoreceptor drum, a toner particle diameter is 4-10 μm, a carrier particle diameter is 10-80 μm, coloring power of each toner is 1.0-1.8, and difference between the maximum and minimum values of coloring powers of YMC is ≤0.5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method and apparatus for use in a laser beam color printer, a color copying machine, and the like, and in particular, in high-speed full-color image formation, an image forming method and an image forming apparatus excellent in prevention of photoreceptor deterioration and durability stability. It is about.

  There are two types of photoreceptors, organic and inorganic.

[Organic photoconductor (OPC)]
In recent years, various organic photoconductive materials have been developed as photoconductive materials for electrophotographic photoconductors. In particular, functionally separated photoconductors in which a charge generation layer and a charge transport layer are laminated have already been put into practical use for copying machines and laser beam printers. It is installed.

  However, it has been considered that one of the major disadvantages of these photoreceptors is their low durability. Durability is broadly classified into durability of electrophotographic physical properties such as sensitivity, residual potential, charging ability, image blur, and mechanical durability such as abrasion and scratches on the surface of the photoreceptor due to rubbing. It has become a big factor to determine the lifespan.

  Among these, the durability of electrophotographic physical properties, particularly image blurring, is caused by deterioration of the charge transport material contained in the surface layer of the photoconductor due to active substances such as ozone and NOx generated from the corona charger. Things are known.

  Regarding mechanical durability, it is known that paper, a cleaning member such as a blade / roller, toner, and the like physically contact and rub against the photosensitive layer.

  In order to improve the durability of electrophotographic physical properties, it is important to use charge transport materials that are not easily degraded by active materials such as ozone and NOx, and it is known to select charge transport materials with high oxidation potential. ing. In addition, in order to increase mechanical durability, in order to eliminate rubbing by paper or a cleaning member, surface lubrication is increased and friction is reduced, and toner filming fusion is prevented. It is important to improve the releasability, and it is known to add a lubricant such as fluorine resin powder, fluorinated graphite, polyolefin resin powder or the like to the surface layer. However, when the wear is remarkably reduced, hygroscopic substances generated by active substances such as ozone and NOx accumulate on the surface of the photoreceptor, and as a result, the surface resistance decreases, the surface charge moves in the lateral direction, and the image blur (image) There is a problem of generating a flow.

[Inorganic photoconductor: amorphous silicon photoconductor (a-Si)]
In electrophotography, as a photoconductive material for forming a photosensitive layer in a photoconductor, it has high sensitivity, a high SN ratio [photocurrent (Ip) / dark current (Id)], and absorption suitable for the spectral characteristics of the electromagnetic wave to be irradiated. Characteristics such as having a spectrum, fast photoresponsiveness, having a desired dark resistance value, and being harmless to the human body during use are required. In particular, in the case of an image forming apparatus photoreceptor incorporated in an image forming apparatus used in an office as an office machine, the above-described pollution-free property is an important point. Hydrogenated amorphous silicon (hereinafter abbreviated as “a-Si: H”) is a photoconductive material exhibiting excellent properties in this respect, and is applied as a photoreceptor for an image forming apparatus. (For example, refer to Patent Document 1).

  In general, a photoreceptor for an image forming apparatus using a-Si: H is obtained by heating a conductive support to 50 to 400 ° C., and vacuum deposition, sputtering, or ion plating on the support. Then, a photoconductive layer made of a-Si is formed by a film forming method such as a thermal CVD method, a photo CVD method, or a plasma CVD method (hereinafter referred to as “PCVD method”). Among these, the PCVD method, that is, the method of decomposing the source gas by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on the support is put to practical use.

  Further, there has been proposed a photoreceptor for an image forming apparatus comprising a conductive support and an a-Si (hereinafter referred to as “a-Si: X”) photoconductive layer containing a halogen atom as a constituent element. (For example, refer to Patent Document 2).

  In this publication, by adding 1 to 40 atomic percent of halogen atoms in a-Si, heat resistance is high and good electrical and optical characteristics can be obtained as a photoconductive layer of a photoreceptor for an image forming apparatus. I can do it.

  In addition, the use environment of the photoconductive member having the photoconductive layer composed of the a-Si deposited film, such as electrical resistance, photosensitivity, photoresponsiveness, etc., such as dark resistance value, photosensitivity, photoresponsiveness, etc. In order to improve the characteristics and stability over time, it was composed of a non-photoconductive amorphous material containing silicon atoms and carbon atoms on a photoconductive layer composed of an amorphous material based on silicon atoms. Techniques for providing a surface layer have been proposed. (For example, refer to Patent Document 3).

  Further, a technique for a photoreceptor in which a light-transmitting insulating overcoat layer containing amorphous silicon, carbon, oxygen and fluorine is laminated is described. (For example, refer to Patent Document 4). A technique using an amorphous material containing silicon atoms, carbon atoms, and 41 to 70 atomic% of hydrogen atoms as constituent elements has been proposed as a surface layer. (For example, refer to Patent Document 5).

  Furthermore, the photoconductive layer contains a-Si: H containing 10 to 40 atomic% of hydrogen and having an absorption coefficient ratio of absorption peaks of 2100 cm −1 and 2000 cm −1 in the infrared absorption spectrum of 0.2 to 1.7. It has been proposed that a photosensitive member for an image forming apparatus having high sensitivity and high resistance can be obtained. (For example, refer to Patent Document 6).

  On the other hand, in order to improve the image quality of the amorphous silicon photoconductor, the temperature in the vicinity of the photoconductor surface is maintained at 30 to 40 ° C., and an image forming process such as charging, exposure, development and transfer is performed. There has been proposed a technique for preventing a decrease in surface resistance due to moisture adsorption and an image flow (high humidity flow) generated therewith. (For example, refer to Patent Document 7).

  These techniques have improved the electrical, optical, photoconductive characteristics and usage environment characteristics of the photoreceptor for image forming apparatus, and the image quality has been improved accordingly.

Japanese Patent Publication No. 60-35059 JP 54-83746 A JP 57-11556 A JP-A-60-67951 JP-A-62-168161 JP 57-158650 A JP-A-60-95551

  In recent years, the expansion of office networks and the diversification of information have spread, and colorization has also progressed for printers and copiers. In particular, as the amount of information increases, full-speed printers and full-color copiers are required to have higher speeds.

  Conventionally, an OPC (organic photoreceptor) has been widely used as a photoreceptor that is a latent image carrier for a full-color copying machine. However, since OPC has low hardness and scrapes, the replacement frequency of the photoconductor increases as the speed increases. For this reason, studies on high-speed copying machines using OPC have been made to increase the hardness to prevent scraping and to cope with higher speeds.

  On the other hand, in an image forming apparatus using an a-Si photosensitive member, since the hardness is high, the replacement frequency of the photosensitive member due to drum scraping can be kept low. Further, the dot reproducibility is good, and particularly when combined with magnetic toner, there is an advantage that a high-quality copy can be obtained.

  However, there are several problems in making a-Si into a digital color copier.

  The a-Si photosensitive member has a problem that image flow occurs under high temperature and high humidity conditions, and the surface potential fluctuates due to temperature fluctuation. In order to solve this problem, a drum heater is placed inside the photoconductor to control the temperature constant.

  On the other hand, since the toner for color copiers is configured to multiplexly fix a plurality of color toners, the softening point of the toner has been set low. When a toner having a high softening point is used, the color mixing property of the fixing device is lost, and a problem occurs in color reproducibility. When such a low softening point toner is used in a high-speed full-color copying machine, the mechanical share is large at the contact portion between the cleaner section and transfer section roller and the photosensitive member, and the calorific value of the photosensitive member is large. As a result, the toner is easily dissolved on the photosensitive member. In particular, when the temperature of the photoconductor is controlled by a drum heater, the problem is more conspicuous, which causes the problem of toner fusion to the photoconductor and the problem of filming in which toner resin is uniformly deposited on the surface of the photoconductor. . For this reason, even when an a-Si photosensitive member is used, maintenance of the photosensitive member is required, and the merit of a long life of a-Si cannot be sufficiently obtained.

  Therefore, when an a-Si photosensitive member is mounted on a color machine, it has been necessary to develop a toner that can reduce fusion and filming on the photosensitive member and achieve both color reproducibility in fixing. Yes.

  Further, when a photoconductor is mounted on a tandem type full-color copying machine, the size of the photoconductor is limited due to the space of the apparatus. As a result, there is a limit to the size of each device that performs the functions of charging, exposure, development, transfer, cleaning, and static elimination. In particular, if the width of the charging device is limited, it is not possible to obtain a sufficient surface potential (charging potential) on the photoreceptor, and as a result, a high-density image cannot be obtained. Therefore, a toner and a developing method that can obtain a sufficient image density even in low potential development are required. Further, even in a system that achieves such low potential development, it is necessary to establish a toner and a development method that provide a high-quality image with excellent color reproducibility.

  Another advantage of using the a-Si photosensitive member in a full-color machine is an increase in image quality. The a-Si photosensitive member has a high reproducibility of dot levels generated by image exposure and can obtain a high-quality image. However, when trying to reduce the diameter of the color toner, the charge amount of the toner increases and generally the toner amount to be developed tends to decrease, which is disadvantageous for the low potential development on the a-Si photoreceptor. Accordingly, there is an urgent need to develop a high-definition and high-quality image forming method and an image forming apparatus that exhibit high developability.

  An object of the present invention is to provide an image forming method and an image forming apparatus that solve the above-described problems.

  An object of the present invention is to provide an image forming method and an image forming apparatus which prevent image flow, photoconductor fusion, and filming under high temperature and high humidity conditions.

  An object of the present invention is to provide an image forming method and an image forming apparatus capable of obtaining a high quality image sufficiently satisfying the color mixing properties of color toners.

  An object of the present invention is to provide an image forming method and an image forming apparatus capable of obtaining a high-quality image excellent in dot reproducibility.

  The present invention solves the above-described problems. According to the present invention, an a-Si photosensitive member is used in a tandem type full-color copying machine, a black toner is used as a one-component developing system, and other color toners are used as a two-component system. It has been found that a full color image forming method and apparatus capable of high definition and high speed can be realized by forming an image using a developing method.

That is, the present invention relates to the first toner image formed by the first image forming unit, the second toner image formed by the second image forming unit, and the third image formed by the third image forming unit. The toner image and the fourth toner image formed by the fourth image forming unit are transferred to the transfer material with or without the intermediate transfer member, and the first, second, third and fourth toner images are transferred. An image forming method for conveying a transfer material having heat and pressure fixing means, performing heat and pressure fixing, and forming a full-color image or a multi-color image on the transfer material,
(A) The first image formation in the first image forming unit is:
(I) at least a first charging step for charging the first photoconductor having amorphous silicon or an amorphous silicon layer, a first exposure step, and a first developing step using a first developing sleeve;
(Ii) The first photoconductor has a diameter of 20 to 80 mm, and the first exposure is performed after the development area of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V in the first charging step. An electrostatic charge image is formed on the first photoconductor by exposure by the process,
(Iii) In the first developing step, a two-component developer containing the first toner and the first magnetic carrier forms a magnetic brush on the first developing sleeve;
(Iv) The first photosensitive member and the first developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The first developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the first photosensitive member, and the first electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a first toner image on the first photoreceptor,
(B) The second image formation in the second image forming unit is:
(I) at least a second charging step for charging the second photosensitive member having amorphous silicon or an amorphous silicon layer, a second exposure step, and a second developing step using a second developing sleeve;
(Ii) The second photoconductor has a diameter of 20 to 80 mm, and the second exposure is performed after the developing area of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V in the second charging step. An electrostatic charge image is formed on the second photoreceptor by exposure in the process,
(Iii) In the second developing step, a two-component developer containing the second toner and the second magnetic carrier forms a magnetic brush on the second developing sleeve;
(Iv) The second photosensitive member and the second developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The second developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the second photoconductor, while the second electrostatic charge image is generated by the magnetic brush of the two-component developer. Is developed to form a second toner image on the second photoreceptor,
(C) The third image formation in the third image forming unit is:
(I) at least a third charging step for charging a third photosensitive member having amorphous silicon or an amorphous silicon layer, a third exposure step, and a third developing step using a third developing sleeve;
(Ii) The third photosensitive member has a diameter of 20 to 80 mm, and the third exposure is performed after the developing region of the photosensitive member facing the developing sleeve is charged to an absolute value of 300 to 450 V in the third charging step. An electrostatic charge image is formed on the third photoconductor by exposure by the process,
(Iii) In the third developing step, a two-component developer containing a third toner and a third magnetic carrier forms a magnetic brush on the third developing sleeve,
(Iv) The third photosensitive member and the third developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The third developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the third photosensitive member, and the third electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a third toner image on the third photoconductor,
(D) The fourth image formation in the fourth image forming unit is:
(I) at least a fourth charging step for charging a fourth photoconductor having amorphous silicon or an amorphous silicon layer, a fourth exposure step, and a fourth developing step using a fourth developing sleeve;
(Ii) The fourth photosensitive member has a diameter of 20 to 80 mm, and after the developing region of the photosensitive member facing the developing sleeve is charged to an absolute value of 300 to 450 V in the fourth charging step, the fourth exposure is performed. An electrostatic charge image is formed on the fourth photoconductor by the process,
(Iii) In the fourth developing step, the fourth developing means has a one-component developer containing the fourth toner and a fourth developing sleeve for transporting the developer to the developing region. ,
(Iv) The fourth photoconductor and the fourth developing sleeve are installed such that the minimum gap is 100 to 500 μm.
(V) The fourth developing sleeve develops the fourth electrostatic charge image with a one-component developer while rotating at a peripheral speed 1.1 to 4.0 times the peripheral speed of the fourth photoconductor. Forming a fourth toner image on the fourth photoreceptor;
(E) The first toner, the second toner, the third toner, and the fourth toner have different color tones, and the nonmagnetic yellow toner, the nonmagnetic magenta toner, the nonmagnetic cyan toner, Selected from the group consisting of magnetic black toner,
(A) Non-magnetic yellow toner, non-magnetic magenta toner, non-magnetic cyan toner and magnetic black toner have positive chargeability, and the weight average particle diameter of each toner is 4.0 to 10.0 μm,
(B) The 50% volume average particle size of the magnetic carrier of the two-component developer is 10 to 80 μm,
(C) For the transfer power of each color, the image density after one-time fixing when the amount of unfixed toner (M / S) on the transfer material is M / S = 0.5 mg / cm ² is defined as D0.5. When the yellow toner coloring power is D0.5Y, the magenta toner coloring power is D0.5M, the cyan toner coloring power is D0.5C, and the black toner coloring power is D0.5Bk, D0.5Y, D0. 5M, D0.5C, and D0.5Bk are 1.0 to 1.8, respectively, and the coloring power of a toner that exhibits the maximum coloring power in three colors of yellow, magenta, and cyan is D0.5max, and the minimum coloring power. In the image forming method, the difference between D0.5max and D0.5min is 0 to 0.5, when the coloring power of the display is D0.5min.

The first toner image formed by the first image forming unit, the second toner image formed by the second image forming unit, the third toner image formed by the third image forming unit, and the fourth toner image The fourth toner image formed by the image forming unit is transferred to the transfer material with or without the intermediate transfer member, and the transfer material having the first, second, third, and fourth toner images is transferred. An image forming apparatus that transports to a heat and pressure fixing means, performs heat and pressure fixing, and forms a full-color image or a multi-color image on a transfer material,
(A) The first image forming unit is
(I) at least a first photosensitive member having amorphous silicon or an amorphous silicon layer, a first charging unit, a first exposure unit, and a first developing unit having a first developing sleeve;
(Ii) The first photoconductor has a diameter of 20 to 80 mm, and the first exposure is performed after the developing region of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V by the first charging unit. An electrostatic charge image is formed on the first photoreceptor by exposure by means,
(Iii) The first developing means has a two-component developer containing a first toner and a first magnetic carrier, and the two-component developer uses a magnetic brush on the first developing sleeve. Forming,
(Iv) The first photosensitive member and the first developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The first developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the first photosensitive member, and the first electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a first toner image on the first photoreceptor,
(B) The second image forming unit is
(I) at least a second photosensitive member having amorphous silicon or an amorphous silicon layer, a second charging unit, a second exposing unit, and a second developing unit having a second developing sleeve;
(Ii) The second photoconductor has a diameter of 20 to 80 mm, and the second exposure is performed after the development area of the photoconductor facing the developing sleeve is charged to 300 to 450 V in absolute value by the second charging unit. An electrostatic charge image is formed on the second photoreceptor by exposure by means,
(Iii) The second developing means has a two-component developer containing a second toner and a second magnetic carrier, and the two-component developer uses a magnetic brush on the second developing sleeve. Forming,
(Iv) The second photosensitive member and the second developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The second developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the second photoconductor, while the second electrostatic charge image is generated by the magnetic brush of the two-component developer. Is developed to form a second toner image on the second photoreceptor,
(C) The third image forming unit is
(I) at least a third photosensitive member having amorphous silicon or an amorphous silicon layer, a third charging unit, a third exposing unit, and a third developing unit having a third developing sleeve;
(Ii) The third photoconductor has a diameter of 20 to 80 mm, and the third exposure is performed after the developing region of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V by the third charging unit. An electrostatic charge image is formed on the third photoreceptor by exposure by means,
(Iii) The third developing means has a two-component developer containing a third toner and a third magnetic carrier, and the two-component developer uses a magnetic brush on the third developing sleeve. Forming,
(Iv) The third photosensitive member and the third developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The third developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the third photosensitive member, and the third electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a third toner image on the third photoconductor,
(D) The fourth image formation in the fourth image forming unit is:
(I) at least a fourth charging step for charging a fourth photoconductor having amorphous silicon or an amorphous silicon layer, a fourth exposure step, and a fourth developing step using a fourth developing sleeve;
(Ii) The fourth photosensitive member has a diameter of 20 to 80 mm, and after the developing region of the photosensitive member facing the developing sleeve is charged to an absolute value of 300 to 450 V in the fourth charging step, the fourth exposure is performed. An electrostatic charge image is formed on the fourth photoconductor by the process,
(Iii) In the fourth developing step, the fourth developing means has a one-component developer containing the fourth toner and a fourth developing sleeve for transporting the developer to the developing region. ,
(Iv) The fourth photoconductor and the fourth developing sleeve are installed such that the minimum gap is 100 to 500 μm.
(V) The fourth developing sleeve develops the fourth electrostatic charge image with a one-component developer while rotating at a peripheral speed 1.1 to 4.0 times the peripheral speed of the fourth photoconductor. Forming a fourth toner image on the fourth photoreceptor;
(E) The first toner, the second toner, the third toner, and the fourth toner have different color tones, and the nonmagnetic yellow toner, the nonmagnetic magenta toner, the nonmagnetic cyan toner, Selected from the group consisting of magnetic black toner,
(A) Non-magnetic yellow toner, non-magnetic magenta toner, non-magnetic cyan toner and magnetic black toner have positive chargeability, and the weight average particle diameter of each toner is 4.0 to 10.0 μm,
(B) The 50% volume average particle size of the magnetic carrier of the two-component developer is 10 to 80 μm,
(C) For the transfer power of each color, the image density after one-time fixing when the amount of unfixed toner (M / S) on the transfer material is M / S = 0.5 mg / cm ² is defined as D0.5. When the yellow toner coloring power is D0.5Y, the magenta toner coloring power is D0.5M, the cyan toner coloring power is D0.5C, and the black toner coloring power is D0.5Bk, D0.5Y, D0. 5M, D0.5C, and D0.5Bk are 1.0 to 1.8, respectively, and the coloring power of a toner that exhibits the maximum coloring power in three colors of yellow, magenta, and cyan is D0.5max, and the minimum coloring power. In the image forming apparatus, the difference between D0.5max and D0.5min is 0 to 0.5, when the coloring power of the display is D0.5min.

  An image forming method and an image forming apparatus according to the present invention include an a-Si photosensitive member having a developer having an appropriate coloring power according to the present invention while controlling the charging potential of the photosensitive member and the rotational speed of the photosensitive member and the developing sleeve. A sufficient image density can be obtained even in the low potential development using, and a high-definition, high-quality full-color image having excellent color reproducibility can be formed.

  The image forming method of the present invention will be described below with reference to the drawings, but this does not limit the present invention.

  FIG. 1 is a schematic configuration diagram of an embodiment of a full-color machine, which is an image forming apparatus that performs the image forming method of the present invention.

  In FIG. 1, each ABCD station indicates an image forming unit that forms a yellow, magenta, cyan, and black image of a full-color image, but the color order of the stations is not black toner but the last station. It doesn't matter. In the following description, for example, the primary charging device 21 indicates the primary charging devices 21A, 21B, 1C, and 21D in each ABCD station.

  In each station, image formation is performed as follows.

  First, a photosensitive drum 4 as a photosensitive member is rotatably provided, and the photosensitive drum 4 is uniformly charged by a primary charging device 21 as a charging unit, and then a light emitting element such as a laser as an exposure unit. An information signal is exposed by 22 to form an electrostatic latent image, and developed by a developing device 9 which is a developing means having a developing sleeve to form a toner image. Next, the toner image is transferred to the transfer paper 24 conveyed by the transfer paper conveyance sheet 27 by the transfer charging device 23.

  On the transfer paper 24, a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are sequentially superimposed and transferred at each station.

  The transfer paper 24 on which the toner images of the four colors are laminated is mixed and fixed by heat and pressure in a fixing device 25 that is a heat and pressure fixing unit, and is discharged out of the device as a full color image.

  Further, the transfer residual toner on the photosensitive drum 4 is removed by the cleaning device 26.

  The present invention provides a tandem type full-color copying machine using a photoreceptor having amorphous silicon or an amorphous silicon layer. By using a tandem type system, it is possible to achieve a high-speed full-color system that can be reduced in size without increasing the moving speed (process speed) of the photoreceptor.

  Further, since there is no potential difference at each developing device position (development region) due to dark decay as compared with a fixed development system of one photosensitive drum, it is easy to perform density control. Further, it is possible to eliminate the problem of density reduction and bulging due to retransfer when using large-diameter a-Si, and characteristic unevenness that is a problem in the production of large-diameter drums.

<1> Image Forming Unit in the Present Invention An image forming apparatus using the image forming method of the present invention is a tandem type color image forming apparatus having four image forming units as shown in FIG. Using a photoconductor having an amorphous silicon or amorphous silicon layer of 20 to 80 mm (hereinafter referred to as “a-Si photoconductor”), the developing area is charged to 300 to 450 V in the charging step, and positively charged as black toner. A toner having a weight average particle diameter of 4.0 to 10.0 μm, and a coloring power of the toner. When the unfixed toner amount (M / S) on the transfer material is M / S = 0.5 mg / cm ² , the image density (D0.5Y, D0.5M, D0. 5C, D0. Bk) is 1.0 to 1.8, and toner of three colors of yellow, magenta and cyan having a difference between the maximum value and the minimum value of D0.5 of 0 to 0.5 is used, and a 50% volume average is used as a magnetic carrier. It was found that by using a carrier having a particle size of 10 to 80 μm, it is possible to obtain a high-quality image with high image density and excellent color reproduction.

  When the diameter of the photoreceptor is smaller than 20 mm, the charging width is limited. Therefore, the surface potential (charge potential) on the photoreceptor is difficult to obtain a sufficient charge potential in consideration of the charging device capability and high voltage leakage, and it is difficult to obtain a high-quality image in development on a high-speed full-color copying machine. Further, since the nip with the developing sleeve is reduced, the developing area is lowered, and the density is likely to be lowered.

  On the contrary, when the diameter of the photoconductor is larger than 80 mm, the charging potential can be sufficiently obtained and the density can be sufficiently obtained, but the toner image or toner on the transfer material formed by the previous image forming unit at the time of transfer can be obtained. Part of the toner is easily retransferred to the photoreceptor. As a result, toner consumption increases and losing margins during transfer are likely to occur. In particular, when image formation is performed at four stations, the image at the first station is retransferred at the second, third, and fourth stations, so that it is difficult to maintain the image density and to remove the edge. Furthermore, there is a drawback that the apparatus becomes large when a large-diameter photoreceptor is used. A more preferable diameter of the photoreceptor is 30 to 80 mm.

  Regarding the charging of the photosensitive member, when the surface potential in the developing region of the photosensitive member facing the developing sleeve is smaller than 300 V in absolute value, a sufficient image density cannot be obtained. When the voltage is higher than 450 V, it is not preferable because density unevenness due to unevenness of the potential of the photoconductor and defects of the photoconductor such as drum ghost are easily picked up and image defects tend to occur.

  In the present invention, the minimum gap between the photosensitive member and the developing sleeve is set to 350 to 800 μm, and the developing sleeve is rotated at a peripheral speed 1.1 to 4.0 times the peripheral speed of the photosensitive member. By developing with a component-based developer magnetic brush, toner fusion to the surface of the photoreceptor does not occur, a sufficient image density is obtained, toner deterioration is also effective, and dot reproducibility However, it was found that a good image can be obtained stably.

  When the minimum gap (SD gap) between the photosensitive member and the developing sleeve is smaller than 350 μm, the share in the gap is increased, and as a result, fusion is likely to occur on the photosensitive member. On the other hand, if it is larger than 800 μm, the toner flying distance becomes long and it becomes difficult for the toner to reach the photoreceptor, so that a sufficient image density cannot be obtained.

  When developing with a magnetic brush composed of a two-component developer while rotating the developing sleeve at a peripheral speed smaller than 1.1 times the peripheral speed of the photoreceptor, it is sufficient because it is difficult to supply the toner necessary for the development. A high image density cannot be obtained. When the developing sleeve is rotated at a peripheral speed greater than 4.0 times the peripheral speed of the photosensitive member, the share in the developing device increases, toner deterioration becomes severe, and the density reduction after continuous use tends to be noticeable. is there. A more preferable peripheral speed of the developing sleeve with respect to the photoreceptor is 1.5 to 3.0 times.

  In the case of one-component development, the minimum gap between the photosensitive member and the developing sleeve is set to 100 to 500 μm, and the developing sleeve is rotated at a peripheral speed 1.1 to 4.0 times the peripheral speed of the photosensitive member. However, by developing from a one-component developer, toner fusion to the surface of the photoreceptor does not occur, a sufficient image density is obtained, toner deterioration is also effective, and dot reproducibility is achieved. It was found that good images can be obtained stably.

  When the minimum gap (SD gap) between the photosensitive member and the developing sleeve is smaller than 100 μm, image defects such as fogging on non-image portions are likely to occur. On the other hand, if it is larger than 500 μm, the toner flying distance becomes long and it becomes difficult for the toner to reach the photoreceptor, so that a sufficient image density cannot be obtained.

  When developing with a one-component developer while rotating the developing sleeve at a peripheral speed smaller than 1.1 times the peripheral speed of the photosensitive member, it is difficult to supply the toner necessary for development, so that sufficient image density is obtained. I can't. When the developing sleeve is rotated at a peripheral speed greater than 4.0 times the peripheral speed of the photosensitive member, the share in the developing device increases, toner deterioration becomes severe, and the density reduction after continuous use tends to be noticeable. is there. A more preferable peripheral speed of the developing sleeve with respect to the photoreceptor is 1.5 to 3.0 times.

(A) Photoreceptor Having Amorphous Silicon or Amorphous Silicon Layer in the Present Invention Next, the a-Si photoreceptor used for the image forming unit in the present invention will be described below.

  FIG. 2 is a schematic configuration diagram for explaining a layer configuration of the a-Si photosensitive member in the present invention.

  In the a-Si photosensitive member 1100 shown in FIG. 2A, a photosensitive layer 1102 is provided on a conductive support 1101 for the photosensitive member. The photosensitive layer 1102 is composed of a photoconductive layer 1103 made of a-Si: H, X and having photoconductivity.

  FIG. 2B is a schematic configuration diagram for explaining the configuration of the photoreceptor layer for an image forming apparatus of the present invention. In the photoreceptor 1100 for an image forming apparatus shown in FIG. 2B, a photosensitive layer 1102 is provided on a conductive support 1101 for the photoreceptor. The photosensitive layer 1102 is composed of a photoconductive layer 1103 made of a-Si: H, X and having photoconductivity, and an amorphous silicon surface layer 1104.

  FIG. 2C is a schematic configuration diagram for explaining the configuration of the photoreceptor layer for an image forming apparatus of the present invention. In the photoreceptor 1100 for an image forming apparatus shown in FIG. 2C, a photosensitive layer 1102 is provided on a conductive support 1101 for the photoreceptor. The photosensitive layer 1102 is composed of a photoconductive layer 110.3 made of a-Si: H, X and having photoconductivity, an amorphous silicon based surface layer 1104, and an amorphous silicon based charge injection blocking layer 1105.

  FIG. 2D is a schematic configuration diagram for explaining still another layer configuration of the photoreceptor for the image forming apparatus of the present invention. In a photoreceptor 1100 for an image forming apparatus shown in FIG. 2D, a photosensitive layer 1102 is provided on a conductive support 1101 for a photoreceptor. The photosensitive layer 1102 includes a charge generation layer 1106 made of a-Si: H, X constituting the photoconductive layer 1103, a charge transport layer 1107, and an amorphous silicon surface layer 1104.

<Conductive support>
The conductive support used in the present invention may be conductive or electrically insulating. Examples of the conductive support include well-known metals such as Al and Fe, and alloys thereof such as stainless steel. Further, a support obtained by conducting a conductive treatment on at least the surface on the side where the photosensitive layer is formed of an electrically insulating support such as a synthetic resin film or sheet, glass or ceramic can also be used.

  The shape of the conductive support 1101 used in the present invention may be a smooth or uneven surface cylindrical or plate-like endless belt.

  In particular, when image recording is performed using coherent light such as laser light, in order to more effectively eliminate image defects due to so-called interference fringe patterns that appear in a visible image, the decrease in charge carriers is substantially reduced. Irregularities may be provided on the surface of the conductive support 1101 within a range that does not exist. The unevenness provided on the surface of the support 1101 can be created by a known method described in JP-A-60-168156, JP-A-60-178457, JP-A-60-225854, or the like.

  In addition, as another method for more effectively eliminating the image defect due to the interference fringe pattern when coherent light such as laser light is used, the surface of the conductive support 1101 is provided with an uneven shape by a plurality of spherical trace depressions. May be. That is, the surface of the conductive support 1101 has finer irregularities than the resolving power required for the photoreceptor 1100 for the image forming apparatus, and the irregularities are due to a plurality of spherical trace depressions. Concavities and convexities due to a plurality of spherical trace depressions provided on the surface of the conductive support 1101 can be created by a known method described in JP-A No. 61-231561.

  As another method for more effectively eliminating the image defect due to the interference fringe pattern when coherent light such as laser light is used, a light absorbing layer or the like in the photosensitive layer 1102 or below the layer 1102 is used. An interference prevention layer or region may be provided.

<Photoconductive layer>
In the present invention, the photoconductive layer is formed on the conductive support 1101 and, if necessary, an undercoat layer (not shown) in order to effectively achieve its purpose, and a part of the photosensitive layer 1102 is formed. It is preferable to configure. The photoconductive layer 1103 can be formed by appropriately setting the numerical conditions of the film formation parameters so as to obtain desired characteristics by a vacuum deposited film forming method. Specifically, for example, a glow discharge method (low frequency CVD method, high frequency CVD method or AC CVD method such as microwave CVD method, or direct current discharge CVD method), sputtering method, vacuum deposition method, ion plating method, It can be formed by a number of thin film deposition methods such as a photo CVD method and a thermal CVD method. These thin film deposition methods are appropriately selected and adopted depending on factors such as manufacturing conditions, degree of load under capital investment, manufacturing scale, and characteristics desired for the image forming apparatus photoreceptor to be created. The glow discharge method is preferable because the control of the conditions for manufacturing the photosensitive member for an image forming apparatus having characteristics is relatively easy.

  In order to form the photoconductive layer 1103 by the glow discharge method, basically, a source gas for supplying Si that can supply silicon atoms (Si) and a source gas for supplying H that can supply hydrogen atoms (H). Or / and a source gas for X supply capable of supplying a halogen atom (X) is introduced in a desired gas state into a reaction vessel capable of reducing the pressure inside thereof to cause glow discharge in the reaction vessel, What is necessary is just to form the layer which consists of a-Si: H, X on the predetermined | prescribed support body 1101 installed in the predetermined position.

  In the present invention, the photoconductive layer 1103 preferably contains hydrogen atoms and / or halogen atoms, which compensates for dangling bonds of silicon atoms and improves layer quality, particularly photoconductivity and charge. This is because it is essential to improve the retention characteristics. Therefore, the content of hydrogen atoms or halogen atoms, or the total amount of hydrogen atoms and halogen atoms is 10 to 30 atom%, more preferably 15 to 25 atom%, based on the sum of silicon atoms and hydrogen atoms or / and halogen atoms. It is desirable that

  Examples of the substance that can be used as a gas for supplying Si used in the present invention include a gas state or a gasified silicon hydride (silanes) that can be effectively used. SiH4 and Si2H6 are preferable in terms of good supply efficiency.

  In order to obtain a film characteristic that achieves the object of the present invention by structurally introducing hydrogen atoms into the photoconductive layer 1103 to be formed, so as to make it easier to control the introduction ratio of hydrogen atoms. It is preferable to form a layer by mixing a desired amount of a gas of a silicon compound containing H 2 and / or He or a hydrogen atom with these gases. In addition, each gas may be mixed in a plurality of types at a predetermined mixing ratio as well as a single type. In addition, effective as the source gas for supplying halogen atoms used in the present invention is preferably a gaseous or gasifiable halogen compound such as halogen gas, halide, silane derivative substituted with halogen, and the like. Further, a silicon hydride compound containing a halogen atom that is gaseous or can be gasified containing silicon atoms and halogen atoms as constituent elements can also be mentioned as effective.

  In order to control the amount of hydrogen atoms and / or halogen atoms contained in the photoconductive layer 1103, for example, the temperature of the support 1101, the reaction of the raw material used to contain the hydrogen atoms and / or halogen atoms What is necessary is just to control the quantity introduce | transduced in a container, discharge electric power, etc.

  In the present invention, it is preferable that the photoconductive layer 1103 contains atoms for controlling conductivity as required. The atoms for controlling the conductivity may be contained in the photoconductive layer 1103 in a uniformly distributed state, or there may be a portion containing the non-uniformly distributed state in the layer thickness direction. Also good.

  Examples of the atoms that control the conductivity include so-called impurities in the semiconductor field. As is well known, atoms belonging to Group 3b of the periodic table (group 3b atoms) or n-type conductivity that give p-type conduction characteristics. An atom (group 5b atom) belonging to group 5b of the periodic table giving characteristics can be used.

  In addition, the material material for introducing atoms for controlling the conductivity may be diluted with H2 and / or He as necessary.

  Further, in the present invention, it is also effective to make the photoconductive layer 1103 contain carbon atoms and / or oxygen atoms and / or nitrogen atoms. Carbon atoms and / or oxygen atoms and / or nitrogen atoms may be uniformly contained in the photoconductive layer, or non-uniform distribution in which the content varies in the thickness direction of the photoconductive layer. There may be a part with

  In the present invention, the layer thickness of the photoconductive layer 1103 is appropriately determined as desired from the viewpoints of obtaining desired electrophotographic characteristics and economic effects, etc., preferably 20-50 μm, more preferably 23-45 μm, optimal Is preferably 25 to 40 μm.

  In order to achieve the object of the present invention and to form a photoconductive layer 1103 having desired film characteristics, the mixing ratio of Si supply gas and dilution gas, gas pressure in the reaction vessel, discharge power and conductive support The body temperature can be set as appropriate.

  Each of the above conditions is not usually determined separately, but it is desirable to determine an optimum value based on mutual and organic relevance in order to form a photoreceptor having desired characteristics.

<Surface layer>
In the present invention, it is preferable to further form a surface layer 1104 on the photoconductive layer 1103 formed on the conductive support 1101 as described above. This surface layer 1104 is provided in order to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability. The surface layer 1104 contains an amorphous silicon (a-Si) -based material, for example, an amorphous silicon containing hydrogen atoms (H) and / or halogen atoms (X) and further containing carbon atoms (hereinafter referred to as “a-SiC”). : H, X "), amorphous silicon containing hydrogen atoms (H) and / or halogen atoms (X) and further containing oxygen atoms (hereinafter referred to as" a-SiO: H, X ") Amorphous silicon containing hydrogen atoms (H) and / or halogen atoms (X) and further containing nitrogen atoms (hereinafter referred to as “a-SiN: H, X”), hydrogen atoms (H) and / or A material such as amorphous silicon (hereinafter referred to as “a-SiCON: H, X”) containing a halogen atom (X) and further containing at least one of a carbon atom, an oxygen atom and a nitrogen atom. It is preferably used.

  In the present invention, in order to effectively achieve the object, the surface layer 1104 is prepared by appropriately setting the numerical conditions of the film forming parameters so as to obtain desired characteristics by a vacuum deposited film forming method. Specifically, for example, a glow discharge method (low frequency CVD method, high frequency CVD method or AC CVD method such as microwave CVD method, or direct current discharge CVD method), sputtering method, vacuum deposition method, ion plating method, It can be formed by a number of thin film deposition methods such as a photo CVD method and a thermal CVD method. These thin film deposition methods are appropriately selected and adopted depending on factors such as manufacturing conditions, degree of load under capital investment, manufacturing scale, and characteristics desired for the image forming apparatus photoconductor to be created. Therefore, it is preferable to use a deposition method equivalent to that of the photoconductive layer.

  For example, in order to form the surface layer 1104 made of a-SiC: H, X by the glow discharge method, basically, a Si supply source gas capable of supplying silicon atoms (Si) and carbon atoms (C) The source gas for supplying C that can supply hydrogen and the source gas for supplying H that can supply hydrogen atoms (H) or / and the source gas for supplying X that can supply halogen atoms (X) are reduced in pressure. A-SiC on a support 1101 on which a photoconductive layer 1103 previously formed at a predetermined position is formed by introducing a glow discharge into the reaction vessel in a desired gas state and generating a glow discharge in the reaction vessel. A layer made of H and X may be formed.

  The amount of carbon when the surface layer is composed mainly of a-SiC is preferably in the range of 30 to 90% with respect to the sum of silicon atoms and carbon atoms.

  In the present invention, the surface layer 1104 needs to contain hydrogen atoms and / or halogen atoms, which compensates for dangling bonds of silicon atoms and improves layer quality, particularly photoconductive properties. And indispensable for improving the charge retention characteristics. The hydrogen content is usually 30 to 70 atomic%, preferably 35 to 65 atomic%, and most preferably 40 to 60 atomic% with respect to the total amount of constituent atoms. The fluorine atom content is usually 0.01 to 15 atom%, preferably 0.1 to 10 atom%, and most preferably 0.6 to 4 atom%. Defects in the surface layer (mainly dangling bonds of silicon atoms and carbon atoms) can be caused by, for example, deterioration of charging characteristics due to injection of charge from the free surface to the photoconductive layer, surface structure under the usage environment, for example, high humidity Fluctuations in charging characteristics due to changes in charge, and afterimage phenomenon during repeated use due to charges injected into the surface layer by the photoconductive layer during corona charging or light irradiation, and trapped in defects in the surface layer It has been known that the characteristics as a photoreceptor for an image forming apparatus are adversely affected such as the occurrence of the above.

  By controlling the hydrogen content in the surface layer to 30 atomic% or more, defects in the surface layer can be greatly reduced, and electrical characteristics and high-speed continuous usability can be improved. On the other hand, when the hydrogen content in the surface layer exceeds 70 atomic%, the durability decreases due to the decrease in the hardness of the surface layer.

  In addition, by controlling the fluorine content in the surface layer within a range of 0.01 atomic% or more, it becomes possible to more effectively achieve the generation of bonds between silicon atoms and carbon atoms in the surface layer. Furthermore, the action of fluorine atoms in the surface layer can effectively prevent the breakage of the bond between silicon atoms and carbon atoms due to damage such as corona. On the other hand, when the fluorine content in the surface layer exceeds 15 atomic%, the effect of bonding between silicon atoms and carbon atoms in the surface layer and the effect of preventing the breaking of bonding between silicon atoms and carbon atoms are hardly recognized. Furthermore, residual potential and image memory are remarkably recognized because excess fluorine atoms impede carrier mobility in the surface layer.

  The fluorine content and hydrogen content in the surface layer can be controlled by the flow rate of H2 gas, the conductive support temperature, the discharge power, the gas pressure, and the like.

  The thickness of the surface layer 1104 in the present invention is usually 0.01 to 3 μm, preferably 0.05 to 2 μm, and most preferably 0.1 to 1 μm. When the layer thickness is less than 0.01 μm, the surface layer is lost due to wear or the like during use of the photoreceptor, and when it exceeds 3 μm, electrophotographic characteristics such as an increase in residual potential are observed.

  The surface layer 1104 according to the present invention is carefully formed so that its required properties are provided as desired. That is, a substance having Si, C and / or N and / or O, H and / or X as a constituent element takes a form from a crystal to an amorphous structure depending on the formation conditions, and is electrically conductive in terms of electrical properties. In the present invention, a compound having a desired characteristic according to the purpose is exhibited, and a property between a photoconductive property and a non-photoconductive property is exhibited. The formation conditions are strictly selected as desired.

  For example, in order to provide the surface layer 1104 mainly for the purpose of improving the pressure resistance, the surface layer 1104 is formed as a non-single crystal material having a remarkable electrical insulating behavior in a use environment.

  In addition, when the main purpose is to improve the continuous and repeated use characteristics and the use environment characteristics, the degree of electrical insulation is relaxed to some extent, and the non-single crystal material has a certain degree of sensitivity to irradiated light. Formed as.

  Furthermore, in order to prevent image flow due to the low resistance of the surface layer 1104 or to prevent the influence of residual potential or the like, on the other hand, in order to improve the charging efficiency, the resistance value is appropriately controlled when forming the layer. Things are preferable.

  Furthermore, in the present invention, it is also possible to provide a blocking layer (lower surface layer) in which the content of carbon atoms, oxygen atoms and nitrogen atoms is reduced from the surface layer between the photoconductive layer and the surface layer. This is effective for further improving the characteristics.

  Further, a region where the content of carbon atoms and / or oxygen atoms and / or nitrogen atoms changes so as to decrease toward the photoconductive layer 1103 may be provided between the surface layer 1104 and the photoconductive layer 1103. As a result, the adhesion between the surface layer and the photoconductive layer can be improved, and the influence of interference due to reflection of light at the interface can be further reduced.

<Charge injection blocking layer>
In the photoreceptor for an image forming apparatus of the present invention, it is more effective to provide a charge injection blocking layer that functions to block charge injection from the conductive support side between the conductive support and the photoconductive layer. Is. That is, the charge injection blocking layer has a function of blocking charge injection from the conductive support side to the photoconductive layer side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. Such a function is not exhibited when subjected to a polar charging treatment, so-called polarity dependency. In order to provide such a function, it is preferable that the charge injection blocking layer contains a relatively large number of atoms for controlling conductivity as compared with the photoconductive layer.

  The atoms controlling the conductivity contained in the layer may be uniformly distributed in the layer, or evenly distributed in the layer thickness direction, but unevenly distributed. There may be a portion that is contained in the state. When the distribution concentration is not uniform, it is preferable to contain it so as to be distributed in a large amount on the support side.

  However, in any case, in the in-plane direction parallel to the surface of the support, it is preferable that it is contained evenly in a uniform distribution from the viewpoint of achieving uniform characteristics in the in-plane direction.

  Examples of the atoms that control the conductivity contained in the charge injection blocking layer include so-called impurities in the semiconductor field, and include a group 3b atom in the periodic table giving p-type conduction characteristics or a period giving n-type conduction characteristics. Table 5b group atoms can be used.

  In the present invention, the content of the atoms for controlling the conductivity contained in the charge injection blocking layer is appropriately determined as desired so that the object of the present invention can be effectively achieved.

  Further, the charge injection blocking layer contains at least one of carbon atom, nitrogen atom and oxygen atom, thereby improving the adhesion between the charge injection blocking layer and another layer provided in direct contact with the charge injection blocking layer. More can be achieved.

  The carbon atoms, nitrogen atoms, or oxygen atoms contained in the layer may be uniformly distributed in the layer or evenly contained in the layer thickness direction, but nonuniformly. There may be a portion contained in a distributed state. However, in any case, in the in-plane direction parallel to the surface of the conductive support, it is preferable that it is evenly distributed and contained evenly from the point of achieving uniform characteristics in the in-plane direction.

  In the present invention, the content of carbon atoms and / or nitrogen atoms and / or oxygen atoms contained in the entire layer region of the charge injection blocking layer is appropriately determined in consideration of charging characteristics and stability during production. In addition, hydrogen atoms and / or halogen atoms contained in the charge injection blocking layer in the present invention compensate for dangling bonds present in the layer, and are effective in improving the film quality.

  In the present invention, the layer thickness of the charge injection blocking layer is preferably from 0.1 to 5 μm, more preferably from 0.3 to 4 μm, optimally from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. It is desirable to be 0.5 to 3 μm.

  In order to form the charge injection blocking layer in the present invention, a vacuum deposition method similar to the method for forming the photoconductive layer described above is employed.

  In addition, in the photoreceptor for an image forming apparatus of the present invention, at least aluminum atoms, silicon atoms, hydrogen atoms and / or halogen atoms are not uniform in the layer thickness direction on the conductive support 1101 side of the photosensitive layer 1102. It is desirable to have a layer region containing in a well distributed state.

  Further, in the photoreceptor for an image forming apparatus of the present invention, for the purpose of improving the adhesion between the conductive support 1101 and the photoconductive layer 1103 or the charge injection blocking layer 1105, for example, Si3N4, SiO2, An adhesion layer made of an amorphous material or the like containing SiO or silicon atoms as a base and containing hydrogen atoms and / or halogen atoms and carbon atoms and / or oxygen atoms and / or nitrogen atoms may be provided.

  Furthermore, as described above, a light absorption layer for preventing the generation of interference patterns due to the reflected light from the support may be provided. A positive or negative photoreceptor is produced by combining these charge injection blocking layer, photoconductive layer, surface layer, and the like.

(B) Method for Producing Photoreceptor in the Present Invention The above-described photoreceptor is prepared using a well-known CVD apparatus.

  FIG. 3 shows an example of a high-frequency plasma CVD method (referred to as “RF-PCVD”) using an RF band. This apparatus is roughly divided into a deposition apparatus (2100), a source gas supply apparatus (2200), and an exhaust apparatus (not shown) for reducing the pressure in the reaction vessel (2111). A cylindrical support (2112), a support heating heater (2113), a source gas introduction pipe (2114) are installed in a reaction vessel (2111) in the deposition apparatus (2100), and a high frequency matching box (2115). Is connected.

  The source gas supply device (2200) includes source gas cylinders (2221 to 2226), valves (2231 to 2236, 2241 to 2246, 2251 to 2256), and mass flow controllers (2211 to 1221) such as SiH4, H2, CH4, B2H6, and PH3. 2216), and each gas cylinder is connected to a gas introduction pipe (2114) in the reaction vessel (2111) via a valve (2260).

  FIG. 4 shows an example of a high-frequency plasma CVD method (referred to as “VHF-PCVD”) using a VHF band. This apparatus is an example of a manufacturing apparatus using the VHF-PCVD method by replacing the deposition apparatus (2100) of FIG. 3 with the deposition apparatus (3100) shown in FIG. 4 and connecting to the source gas supply apparatus (2200). . This apparatus is roughly divided into a reaction vessel (3111) that can be depressurized in a vacuum-tight structure, a source gas supply device (2200), and an exhaust device (not shown) for depressurizing the inside of the reaction vessel. Has been. A cylindrical support (3112), a conductive support heating heater (3113), and an electrode are installed in the reaction vessel (3111), and a high-frequency matching box (3120) is further connected to the electrode. The reaction vessel (3111) is connected to a diffusion pump (not shown) through an exhaust pipe (3121). A space (3130) surrounded by the cylindrical conductive support (3112) forms a discharge space.

(C) Developing Device in the Present Invention The developing device used in the image forming unit in the present invention is a two-component developing method in which black toner is a one-component developing method and the other colors constitute a magnetic brush. What is the minimum gap between the developing sleeve and the photoconductor? There is no particular limitation as long as the one-component developing method is 100 to 500 μm and the two-component developing method is 350 to 800 μm, and a normal developing device can be used.

  FIG. 5 shows an example of a developing device used in the image forming unit.

  In FIG. 5, the developing device 9 disposed opposite to the photosensitive drum 4 includes a developing container 8, a developing sleeve 3 as a developer conveying means, a developer returning member 1 that regulates a developer reservoir 5, and a developing device. It has a blade 2 as an agent head height regulating member. The interior of the developing device 9 is partitioned into a developing chamber (first chamber) 13 and a stirring chamber (second chamber) 14 by a partition wall 6 extending in the vertical direction, and an upper portion of the partition wall 6 is open. The developing chamber 13 and the stirring chamber 14 contain a two-component developer containing a non-magnetic color toner and a magnetic carrier, and the two-component developer that has become redundant in the developing chamber 13 is placed on the stirring chamber 14 side. To be recovered.

  First and second stirring screws 11 and 12 are arranged in the developing chamber 13 and the stirring chamber 14, respectively.

  The developing chamber 13 of the developing device 9 has an opening at a position corresponding to the developing area facing the photosensitive drum 4, and the developing sleeve 3 is rotatably arranged so as to be partially exposed to the opening. The developing sleeve 3 is made of a nonmagnetic material, and rotates in the direction of the arrow in the drawing operation. A magnet (magnet roller) 10 serving as a magnetic field generating means is fixed inside the developing sleeve 3. The developing sleeve 3 carries and conveys a layer of a two-component developer whose layer thickness is regulated by the blade 2 and supplies the developer to the photosensitive drum 4 in a developing area facing the photosensitive drum 4 to develop the latent image. In order to improve the developing efficiency, a developing bias voltage in which an AC voltage is superimposed on a DC voltage, for example, is applied to the developing sleeve 3 from a power source 15.

  With the above-described configuration, the developing device 9 holds the two-component developer supplied to the surface of the developing sleeve 3 by the stirring screws 11 and 12 in the state of a magnetic brush by the magnetic force of the magnet roller 10, and holds this in the developing sleeve. 3 is transported to a portion (development area) opposite to the photosensitive drum 4 based on the rotation of 3, and the developer returning member 1 and the blade 2 cut off the magnetic brush and feed the developer amount to the development area appropriately. To maintain.

  More specifically, the magnet roller 10 of such a developing device has a five-pole configuration, and the developer stirred by the developing chamber stirring screw 11 is restrained by the magnetic force of the conveying magnetic pole (pumping pole) N2 for pumping. Then, the developer is conveyed to the developer reservoir 5 by the rotation of the developing sleeve 3. The developer amount is regulated by the developer returning member 1, and in order to restrain the stable developer, the developer magnetic pole (cut pole) S2 having a magnetic flux density of a certain level or more is sufficiently restrained to form a magnetic brush. While being conveyed. Next, the magnetic brush is trimmed by the blade, that is, the head height regulating member 2 so that the developer amount is appropriate, and the developer is conveyed by the conveying magnetic pole N1. Further, a bias voltage in which a direct current and / or an alternating electric field is superimposed is applied to the developing sleeve 3 via a bias power source 15 provided on the image forming apparatus main body side at the developing pole S1, and the toner on the developing sleeve 3 is transferred to the photosensitive drum. 4 is moved to the electrostatic latent image side, and the electrostatic latent image is visualized as a toner image. An ordinary exposure apparatus may be used for the image forming unit. That is, with a positively chargeable toner, a latent image is formed by image exposure when a positively charged photoreceptor is used, and a latent image is formed by backscan exposure when a negatively charged photoreceptor is used. As shown in FIG. 1, the image forming unit preferably further includes a transfer unit such as a transfer charging device, a cleaning device, and the like, and these may be those used in a normal image forming apparatus.

  An example of a one-component developing device is shown in FIG. A developing container 8D for containing the developer, a developing sleeve 3D that is rotatably provided as an opening of the developing container 8D as a fourth developing sleeve, a blade 2D that regulates the amount of developer on the developing sleeve 3D, and a developing sleeve 3D It has a magnet roll 5 as a magnetic field generating means fixed inside, and an agitating member 7 for agitating the developer contained in the developing container 8D. A power supply 15D is connected to the developing sleeve 3D, and the power supply 15D is configured to apply a desired developing bias to the developing sleeve 3D.

  The present invention is favorably used for a method of transferring to a transfer material with or without an intermediate transfer member, but is particularly preferably used when an intermediate transfer member is used.

<2> Developer in the Present Invention Next, the developer and toner in the present invention will be described.

  The color toner (yellow toner, magenta toner, cyan toner) in the present invention is a positively chargeable non-magnetic toner, used as a two-component developer together with a magnetic carrier, and the black toner is a positively chargeable magnetic toner. .

Further, in the present invention, the color strength of each toner is set so that each color image is normally fixed once when the amount of unfixed toner (M / S) on the transfer material is M / S = 0.5 mg / cm ^2. The density (D0.5Y, D0.5M, D0.5C, D0.5Bk) is 1.0 to 1.8, and the difference between the maximum value and the minimum value of D0.5 for three colors of yellow, magenta, and cyan is 0. Use ~ 0.5 toner.

When the amount of unfixed toner on the transfer material (M / S) is M / S = 0.5 mg / cm ² , each color image density (D0.5) after one-time fixing is usually determined by the colorant in the toner. It can be changed depending on the amount added and the dispersion of the colorant. When D0.5 is 1.0 or less, if an a-Si photosensitive member is used and image formation is performed under conditions where the charged potential is sufficiently high, the density tends to decrease.

  When D0.5 is prepared only by the amount of pigment added, the amount of pigment in the toner becomes excessive, so that charging of the toner is inhibited or the fixing property varies with changes in viscoelasticity. Further, the pigment is easily detached from the toner during the durability, and fogging, filming, and thus spent on the blade and sleeve are easily generated, and the transparency is also deteriorated. Therefore, it is preferable to control D0.5 in consideration of not only the addition amount but also pigment selection, dispersion, and state. However, even when D0.5 is increased by controlling charging inhibition and viscoelasticity of the toner, if D0.5 is larger than 1.8, halftone reproducibility is lowered, and in addition, density gradation Rises rapidly, and control over environmental fluctuations becomes strict, which is not preferable. Therefore, the coloring power D0.5 of the toner of the present invention is desirably 1.0 to 1.8, and preferably 1.1 to 1.7.

  In addition, when the difference between the maximum value and the minimum value of D0.5 for the three colors of yellow, magenta, and cyan is greater than 0.5, the difference in gloss at the same image density portion of each color increases, making it difficult to obtain a high-quality image. . Furthermore, the environmental characteristics of each toner are easily expanded, and the color balance at the time of full color formation is easily lost due to temperature and humidity. Therefore, the difference between the maximum value and the minimum value of D0.5 for the three colors of yellow, magenta, and cyan is preferably set in the range of 0 to 0.5. More preferably, it is 0-0.4.

  Next, the pigment used in the present invention will be described. In the present invention, the type of the pigment is not particularly limited, but it does not become a dispersibility to the resin, an improvement in color reproducibility, a high coloring power, a high light resistance, and a charging inhibitor. It is determined as appropriate in consideration of the above.

  Examples of the yellow pigment used in the yellow toner include CI Pigment Yellow 74, 93, 97, 109, 128, 151, 154, 155, 166, 168, 180, and 185.

  As the magenta pigment used in the magenta toner, a quinacridone pigment, CI Pigment Red (CI Pigment Red) 48: 2, 57: 1, 58: 2, or Shii Eye Pigment Red ( CI Pigment Red) 5, 31, 146, 147, 150, 184, 187, 238, 245, or CI Pigment Red 185, 265.

  Examples of the cyan pigment used in the cyan toner include a Cu-phthalocyanine pigment and an Al-phthalocyanine pigment. The Cu-phthalocyanine pigment may be a copper phthalocyanine pigment in which 1 to 5 phthalimidomethyl groups are substituted on a phthalocyanine skeleton having a structure represented by the following formula (I).

  The black pigment used in the black toner is not particularly limited as long as it has black magnetism, but magnetite is preferably used.

  By using these pigments, the dispersibility of the pigment in the binder resin is improved, and as a result, the coloring power is improved, low-potential development is possible, and a good full-color image can be formed.

  The yellow pigment content is 12 parts by mass or less, preferably 0.5 to 8 parts by mass with respect to 100 parts by mass of the binder resin, with respect to the yellow toner sensitively reflecting the transparency of the OHP film. preferable. When the amount exceeds 12 parts by mass, the reproducibility of the mixed colors of yellow, green, red, and human skin color as an image tends to be inferior.

  With respect to the magenta toner and the cyan toner, the content of the magenta pigment or the cyan pigment is preferably 15 parts by mass or less, more preferably 0.1 to 9 parts by mass with respect to 100 parts by mass of the binder resin. For the black toner, the black pigment content is preferably 15 parts by mass or less, more preferably 0.1 to 9 parts by mass with respect to 100 parts by mass of the binder resin. In order to produce the toner according to the present invention, a pigment or dye as a colorant, a charge control agent, other control agents, and the like are added to the binder resin as necessary, and the mixture is sufficiently mixed with a mixer such as a ball mill. After mixing, using a heat kneader such as a heating roll, kneader, extruder, etc., while melting and kneading to melt the resins together, the pigments or dyes are dispersed or dissolved, cooled, solidified and ground The toner particles according to the present invention can be obtained by performing strict classification. However, in order to obtain a toner having a coloring power with the image density (D0.5) of 1.0 to 1.8, it is preferable to perform the pigment dispersion method shown below when preparing the toner.

  That is, in the present invention, in order to achieve a specific dispersion state of the pigment particles in the toner particles as described above, 5 to 50 mass of the first binder resin and the pigment particles insoluble in the dispersion medium are used. 1% of the paste pigment is charged into a kneader or mixer and heated while mixing without pressure to melt the first binder resin, and the paste pigment, that is, the pigment in the liquid phase is heated. The first binder resin and the pigment particles are transferred to the first binder resin, that is, the molten resin phase, and then the first binder resin and the pigment particles are melt-kneaded, the liquid is removed and evaporated to dryness. Then, a mixture obtained by adding a second binder resin and, if necessary, an additive such as a charge control agent to the first kneaded product is heated and melt-kneaded to obtain a second kneaded product. And kneaded and classified the second kneaded material obtained after cooling. It is preferable that the reduction. Here, the first binder resin and the second binder resin may be the same or different binder resins.

  In the present invention, the paste pigment refers to a state in which the pigment particles exist in the first kneaded product production process without passing through the drying process. In other words, the pigment particles are in the state of approximately 50% by mass with respect to the total paste pigment in the state of primary particles. The remaining 50 to 95% by mass in the paste pigment is occupied by most volatile liquids along with some dispersants and auxiliaries. The volatile liquid is not particularly limited as long as it is a liquid that evaporates by general heating, but is particularly preferably used in the present invention, and the liquid that is also preferably used ecologically is water. In the present invention, insoluble pigment particles are pigment particles that are insoluble in a dispersion medium, which is a volatile liquid in the paste pigment, and can be dispersed in the paste pigment. For example, when water is selected as the volatile liquid, all the water-insoluble pigment particles are insoluble pigment particles.

  The paste pigment used in the present invention preferably contains 5 to 50 mass%, more preferably 5 to 45 mass%, of water-insoluble pigment particles. When the content of the insoluble pigment exceeds 50% by mass, the dispersion efficiency into the binder resin is low, the kneading temperature must be high, or the kneading time must be set long. Furthermore, a powerful screw or paddle configuration is essential for the kneading apparatus, which easily causes polymer chain breakage.

  Conversely, when the paste pigment contains less than 5% by weight of an insoluble pigment in solid content, in order to obtain the desired pigment content, a large amount of paste pigment must be introduced into the mixing device, This is not preferable because the mixing apparatus becomes large. Further, if it is less than 5% by mass, the water removal process in the process after the first kneading must be strengthened and water must be completely blown off, resulting in a large load on the binder resin. It will end up.

  When the paste pigment and the binder resin are kneaded or mixed, the ratio of the pigment and the binder resin in terms of solid content is 10:90 to 50:50, preferably 15:85 to 45:55.

  When the ratio of the paste pigment to the binder resin is less than 10% by mass, a large amount of the binder resin must be charged into the kneading machine with respect to the paste pigment, and the segregation of the pigment easily occurs in the kneaded product. In order to achieve this, the kneading time must be set longer. In this case, an excessive load is applied to the binder resin, and it is difficult to obtain desired resin characteristics.

  When the ratio of the pigment to the binder resin is more than 50% by mass, the transition of the pigment particles in the liquid phase to the binder resin is not easily performed, and in addition, even during melt kneading after the migration of the pigment particles The kneaded product hardly exhibits a uniform molten state, and as a result, it is difficult to obtain good dispersibility.

  In the present invention, it is preferable to melt-knead under non-pressurization because the liquid (for example, water) in the paste pigment attacks the binder resin under pressure and causes some hydrolysis reaction, or There is also a possibility that the binder resin may be deteriorated, and the offset resistance may be lowered. Therefore, in the present invention, it is preferable to melt-knead the first binder resin and the paste pigment under no pressure.

  Examples of the kneading apparatus used in the present invention include a heating kneader, a single screw extruder, a twin screw extruder, a kneader, and the like, and particularly preferably a heating kneader.

  As the binder resin used in the present invention, various resins conventionally known as binder resins for electrophotography are used.

  For example, polystyrene, styrene copolymer such as styrene / butadiene copolymer, styrene / acryl copolymer, polyethylene, ethylene vinyl acetate copolymer, phenol resin, epoxy resin, acrylic phthalate resin, polyamide resin, polyester Resin, maleic acid resin, and the like are used. In the present invention, when a polyester resin is used as a main component as a binder resin, good pigment dispersibility and charging stability can be achieved.

  The polyester resin will be described in more detail below.

  The polyester resin is obtained by polycondensation of an alcohol component and an acid component. Examples of the acid component constituting the polyester resin preferably used in the present invention include terephthalic acid, isophthalic acid, phthalic acid as aromatic dicarboxylic acids. Acid, diphenyl-P, P′-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, diphenylmethane-P, P′-dicarboxylic acid, benzophenone-4,4′-dicarboxylic acid, 1,2-diphenoxyethane-P, P′-dicarboxylic acid can be used, and other acids include maleic acid, fumaric acid, glutaric acid, cyclohexanedicarboxylic acid, succinic acid, malonic acid, adipic acid, mesaconic acid, Itaconic acid, citraconic acid, sebacic acid, anhydrides of these acids, lower alkyl esters Tell can be used.

  Examples of the divalent alcohol include diols represented by the following formula (II).

（式中、Ｒ₁は炭素数２〜５のアルキレン基であり、Ｘ，Ｙは正数であり、２≦Ｘ＋Ｙ≦６）

(Wherein R ₁ is an alkylene group having 2 to 5 carbon atoms, X and Y are positive numbers, 2 ≦ X + Y ≦ 6)

  For example, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) Examples include -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (13) -2,2-bis (4-hydroxyphenyl) propane.

  Examples of other divalent alcohols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-butenediol. Diols such as 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, and hydrogenated bisphenol A.

  Examples of the polyester resin in the present invention include n-dodecenyl group, isododecenyl group, n-dodecyl group, isododecyl group, isooctyl group and the like, such as maleic acid, fumaric acid, glutaric acid, succinic acid, malonic acid, adipic acid, It may contain an acid having an alkyl or alkenyl substituent and / or an alcohol such as ethylene glycol, 1,3-propylenediol, tetramethylene glycol, 1,4-butylenediol, 1,5-pentyldiol.

  Examples of the production method for obtaining the polyester resin used in the toner of the present invention include the following methods.

  First, a linear condensate is formed, and in the process, the molecular weight is adjusted so that the target acid value becomes 1.5 to 3 times the hydroxyl value, and the molecular weight becomes uniform more slowly than before. In order for the condensation reaction to proceed gradually, for example, (i) the reaction is carried out at a lower temperature for a longer time than before, (ii) the esterifying agent is reduced, (iii) a less reactive esterifying agent is used, or (iv) The reaction is controlled by using a combination of these methods. Thereafter, a crosslinking acid component and, if necessary, an esterifying agent are further added under the conditions, and reacted to form a three-dimensional condensate. The temperature is further raised, the reaction is slowly performed for a long time so that the molecular weight distribution becomes uniform, the crosslinking reaction proceeds, and when the hydroxyl value or acid value or MI (Melt Index) value falls to the target value, the reaction is terminated. Obtain a resin.

  In the present invention, the polyester resin preferably has an acid value of 35 mgKOH / g or less, and more preferably 30 mgKOH / g or less. When the acid value is 35 mgKOH / g, excellent charging stability can be obtained in each environment. When the acid value of the polyester resin is larger than 35 mgKOH / g, it becomes difficult to make the toner positively charged well, and image defects such as thin image density and fog are likely to occur.

  In the present invention, considering the storage stability and fixability of the toner, and the color mixing with other toners, the glass transition temperature of the toner is preferably 50 to 70 ° C., preferably 52 to 68 ° C. In order to set the glass transition temperature of the toner within the above range, a binder resin in the toner having a glass transition temperature within the above range may be used. In order to set the glass transition temperature of the binder resin used in the present invention within the above range, it may be appropriately determined from the molecular weight, the material, and the like. When the glass transition temperature of the toner is less than 50 ° C., although the fixing property is excellent, the offset resistance is reduced, and the fixing roller may be contaminated or wound around the fixing roller. Furthermore, since the gloss on the image surface after fixing becomes too high, the image quality may be deteriorated.

  On the other hand, if the glass transition temperature of the toner is higher than 70 ° C., the fixability tends to deteriorate, so the set fixing temperature of the copying machine main body has to be raised, and the resulting image generally has a low gloss. In addition, the color mixing property is reduced for a full color toner. The binder resin used in the present invention has a number average molecular weight (Mn) of preferably 1500 to 20000, more preferably 2000 to 15000, and a weight average molecular weight (Mw) of preferably 6000 to 100,000, more preferably 8000 to 80000. Yes, Mw / Mn is preferably 2-10. A binder resin that satisfies the above conditions has good thermal fixability, improved dispersibility of the colorant, less variation in the charge amount of the color toner, and improved image quality reliability.

  In the case where the number average molecular weight (Mn) of the binder resin is less than 1500 or the weight average molecular weight (Mw) is less than 6000, the smoothness of the surface of the fixed image is high, but the vividness of the look is high. In the endurance, offset tends to occur, storage stability is lowered, and there are concerns about new problems such as occurrence of toner fusion in the developing device. Further, it is difficult to apply a share when the toner raw material is melt-kneaded at the time of producing the toner particles, the dispersibility of the chromatic colorant is likely to be lowered, the toner coloring power is lowered, and the toner charge amount is likely to be changed.

  In the case where the number average molecular weight (Mn) of the binder resin exceeds 20000 or the weight average molecular weight (Mw) exceeds 100,000, both have excellent offset resistance, but the fixing set temperature must be increased, Furthermore, even if the degree of pigment dispersion can be controlled, the surface smoothness in the image area tends to decrease, and the color reproducibility tends to decrease.

  When the Mw / Mn of the binder resin is less than 2, the molecular weight itself is small, and as in the case of the small molecular weight, offset development due to durability, reduction in storage stability, and toner in the developing device. Fusing tends to occur, and toner charge amount variation tends to occur.

  When the Mw / Mn of the binder resin exceeds 10, although the offset resistance is excellent, the fixing set temperature must be increased, and even if the degree of pigment dispersion can be controlled, the image area There is a tendency that the surface smoothness at the surface is lowered, and the color reproducibility tends to be lowered.

  The toner of the present invention preferably has a softening point temperature Tm calculated from a flow tester curve of 85 ° C. ≦ Tm ≦ 120 ° C.

  When the softening point temperature Tm of the toner is higher than 120 ° C., although it has excellent offset resistance, the fixing set temperature must be increased, and even if the degree of pigment dispersion can be controlled, There is a tendency for the surface smoothness of the toner to greatly decrease, and high color reproducibility cannot be expected.

  When the Tm of the toner is lower than 85 ° C., the smoothness of the fixed image is surely high, but the perceived vividness is apt to occur, but offset tends to occur in the durability. Furthermore, the storage stability is poor, and there are concerns about new problems such as toner fusion in the developing device. Therefore, the softening point temperature Tm of the toner is preferably 85 ° C. ≦ Tm ≦ 120 ° C., more preferably 90 ° C. ≦ Tm ≦ 115 ° C.

  The toner in the present invention may be added with a positive charge control agent as necessary, and comprises a quaternary ammonium salt, an imidazole compound, an ammonio group-containing styrene acrylic copolymer resin, and a phosphonium compound as the positive charge control agent. It is desirable to contain at least one selected from the group.

  Among them, a quaternary ammonium salt and imidazole, which are white charge control agents, are preferably used for color toners. The quaternary ammonium salt contained in the nonmagnetic toner of the present invention is represented by the following general formula (III).

（式中、Ｒ₂〜Ｒ₅は、それぞれ独立に、水素原子、アルキル基、アルケニル基、未置換芳香族基あるいは置換芳香族基等を表わし、Ａ^-はカウンターのアニオンを表わす。

(Wherein R _{2 to} R ₅ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an unsubstituted aromatic group or a substituted aromatic group, and A ⁻ represents an anion of a counter.

Among R _{2 to} R ₅ , one or more groups have 6 or more carbon atoms, and further 10 or more, especially 12 or more alkyl groups, alkenyl groups, unsubstituted aromatic groups or substituted fragrances. What is a group is preferable.

In addition, examples of the anion of the counter represented by A ⁻ include halogen ions such as Cl—, Br—, and I—halate ions such as ClO-3, ClO-4, IO-3, and IO-4; Represented by (IV),

  Sulfonic acid ions such as CH3SO3-; sulfate ions; BF4-, PF6-; molybdate ions such as Mo7O246-, H2W12O42 10-, PO4W12O403-, tungstate ions; Can be mentioned.

  Examples of the quaternary ammonium salt used in the present invention include the following. Hoechst VP2036 (melting point: 200 ° C.), VP2038 (melting point: 215 ° C.); Hodogaya Chemical Industries, Ltd. TP302 (melting point: 215 ° C.), TP415 (melting point: 204 ° C.), TP4040 (melting point: 209 ° C.); A-902 (melting point: 210 ° C.) manufactured by Nippon Carlit.

  On the other hand, the functional group that imparts positive chargeability to the toner with the charge control resin includes various groups. Among them, a trisubstituted ammonio group is particularly preferable, and among them, a trialkylammonio group represented by the following general formula (V) However, since it is excellent in the function to provide positive charging property, it is more preferable.

（式中Ｒａ、ＲｂおよびＲｃは、同一または異なって、メチル基、エチル基、ノルマルプロピル基、イソプロピル基、ノルマルブチル基、イソブチル基、３級ブチル基、ペンチル基、ヘキシル基等のアルキル基を示し、Ｂ−はモリブデン酸イオン、リンモリブデン酸イオン、クロムモリブデン酸イオン、リンタングステン酸イオン、ケイタングステン酸イオン、アンチモン酸イオン、ビスマス酸イオン、塩素イオン、臭素イオン、ヨウ素イオン、硝酸イオン、硫酸イオン、過塩素酸イオン、過ヨウ素酸イオン、安息香酸イオン、ナフトールスルホン酸イオン、ベンゼンスルホン酸イオン、トルエンスルホン酸イオン、キシレンスルホン酸イオン、テトラフェニルホウ素イオン、テトラフルオロホウ素イオン、テトラフルオロリンイオン、ヘキサフルオロリンイオンを示す。）

(In the formula, Ra, Rb and Rc are the same or different and each represents an alkyl group such as a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, a tertiary butyl group, a pentyl group or a hexyl group). B- represents molybdate ion, phosphomolybdate ion, chromium molybdate ion, phosphotungstate ion, silicotungstate ion, antimonate ion, bismuth acid ion, chlorine ion, bromine ion, iodine ion, nitrate ion, sulfuric acid Ions, perchlorate ions, periodate ions, benzoate ions, naphthol sulfonate ions, benzene sulfonate ions, toluene sulfonate ions, xylene sulfonate ions, tetraphenyl boron ions, tetrafluoro boron ions, tetrafluoro phosphorus ions, Heki Shows a fluorophosphate ion.)

  As the main chain of the charge control resin, various polymer main chains can be adopted. In particular, compatibility with the polyester resin as the fixing resin is important in terms of the transparency and positive chargeability of the toner. Therefore, it is preferable to use a polymer main chain having good compatibility with the polyester resin. Examples of such a polymer main chain include styrene-acrylic copolymer resins such as styrene-acrylic acid ester copolymers and styrene-methacrylic acid ester copolymers. When the styrene acrylic copolymer resin is a main chain, the functional group is preferably substituted with an acrylic ester portion.

  In addition, as the positive charge control agent used in the present invention, an imidazole derivative represented by the following formula (VI) is preferably used.

（式中、Ｒ₁’〜Ｒ₄’は、水素、アルキル基、アラルキル基及びアリール基からなる群から選択される置換基を示し、これらは、同一或いはそれぞれ異なっていても良く、且つ置換されていても良い。Ｘ’はフェニレン基、プロペニレン基、ビニレン基、アルキレン基及び−Ｃ（Ｒ₅’）Ｒ₆’−からなる群から選択される連結基を示し、Ｒ₅’及びＲ₆’は水素、アルキル基、アラルキル基及びアリール基からなる群から選択される置換基を示す。）

(Wherein R ₁ ′ to R ₄ ′ represent a substituent selected from the group consisting of hydrogen, an alkyl group, an aralkyl group and an aryl group, and these may be the same or different and may be substituted. X ′ represents a linking group selected from the group consisting of a phenylene group, a propenylene group, a vinylene group, an alkylene group and —C (R ₅ ′) R ₆ ′ —, and R ₅ ′ and R ₆ ′. Represents a substituent selected from the group consisting of hydrogen, an alkyl group, an aralkyl group and an aryl group.

Examples of the substituent when the substituents R ₁ ′ to R ₄ ′ are further substituted include an amino group, a hydroxyl group, an alkyl group, an alkoxy group, and a halogen.

Specific examples of R ₁ ′ to R ₄ ′ include hydrogen, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heneicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, i-propyl group, i-butyl Group, t-butyl group, cyclopentyl group, cyclohexyl group, benzyl group, phenethyl group, diphenylmethyl group, trityl group, cumyl group, phenyl group, tolyl group, xylyl group, mesityl group, naphthyl group and anthryl group.

Further, in R ₁ ′ to R ₄ ′, the alkyl group preferably has 1 to 25 carbon atoms, the aralkyl group preferably has 7 to 20 carbon atoms, and the aryl group has 6 to 20 carbon atoms. It is good to be.

In R ₅ ′ and R ₆ ′, the alkyl group preferably has 1 to 20 carbon atoms, the aralkyl group preferably has 7 to 15 carbon atoms, and the aryl group has 6 to 15 carbon atoms. It is good to be.

  The imidazole derivative represented by the formula (VI) used in the present invention is particularly preferably an imidazole derivative represented by the following formula (VII) or (VIII).

In the formula, R ₁ ′ and R ₂ ′ are a substituent selected from the group consisting of an alkyl group having 5 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. These may be the same or different, and may be substituted. Examples of the substituent when substituted include an amino group, a hydroxyl group, an alkyl group, an alkoxy group, and a halogen.

R ₃ ′ to R ₆ ′ represent a substituent selected from the group consisting of hydrogen, an alkyl group, an aralkyl group, and an aryl group, and these may be the same or different from each other and may be substituted. . Examples of the substituent when substituted include an amino group, a hydroxyl group, an alkyl group, an alkoxy group, and a halogen.

Furthermore, the alkyl group of R ₃ ′ to R ₆ ′ preferably has 1 to 6 carbon atoms, the aralkyl group preferably has 7 to 15 carbon atoms, and the aryl group has 6 to 15 carbon atoms. It is good to be.

In the formula, R ₁ ′ and R ₂ ′ are substituents selected from the group consisting of an alkyl group having 5 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms. These may be the same or different, and may be substituted. Examples of the substituent when substituted include an amino group, a hydroxyl group, an alkyl group, an alkoxy group, and a halogen.

R ₃ ′ and R ₄ ′ represent a substituent selected from the group consisting of hydrogen, an alkyl group, an aralkyl group and an aryl group, and these may be the same or different from each other, and may be substituted. Examples of the substituent when substituted include an amino group, a hydroxyl group, an acetyl group, an alkoxy group, and a halogen.

Further, the alkyl group of R ₃ ′ and R ₄ ′ preferably has 1 to 6 carbon atoms, the aralkyl group preferably has 7 to 15 carbon atoms, and the aryl group has 6 to 15 carbon atoms. It is good to be.

  The imidazole derivative represented by the formula (VII) is excellent in dispersibility in the binder resin, and the imidazole derivative represented by the formula (VIII) is excellent in dispersibility, Therefore, the occurrence of sleeve contamination due to the elimination of the imidazole derivative from the toner is suppressed.

In the above formulas (VII) and (VIII), when the carbon number of the alkyl group of R ₁ ′ and R ₂ ′ is less than 5, the positive charging ability is lowered, and in order to exhibit the effect as a positive charge control agent In addition, an increase in the amount of addition is required. On the other hand, when the carbon number of the alkyl group, aralkyl group and aryl group of R ₁ ′ and R ₂ ′ exceeds 20, the melting point of the imidazole derivative itself is lowered. Since the melt viscosity is lowered and uniform dispersion in the binder resin is difficult, image characteristics are likely to be deteriorated due to poor dispersion, and thus the binder resin may be limited.

  In the present invention, the imidazole derivative is 0.01 to 20.0 parts by mass, preferably 0.1 to 10.0 parts by mass, more preferably 0.5 to 5.0 parts by mass with respect to 100 parts by mass of the binder resin. It is good to add. When the addition amount is less than 0.01 parts by mass, the toner cannot have a sufficient charge amount, and the effect of adding the imidazole derivative may not appear. On the other hand, when the addition amount is more than 20.0 parts by mass, excessive addition occurs, causing poor dispersion in the toner, increasing the possibility of being present in aggregates, and the amount of imidazole derivative present per toner particle is large. It tends to be non-uniform and is not preferred.

  When an imidazole derivative is used in the present invention, it can be used in combination with a conventionally known positive charge control agent.

  The imidazole derivative used in the present invention is synthesized as follows.

  To the imidazole derivative represented by the following general formula (D) using ethanol as a solvent, aldehyde and potassium hydroxide as a solvent are added and refluxed for several hours. The precipitate deposited by refluxing is filtered, washed with water, and recrystallized again with methanol.

（Ｒは、水素、アルキル基、アリール基及びアラルキル基からなるグループから選択される置換基を示し、これらは同一であっても異なっていても良い。）

(R represents a substituent selected from the group consisting of hydrogen, an alkyl group, an aryl group, and an aralkyl group, which may be the same or different.)

  This synthesis method does not limit the imidazole derivative used in the present invention. Examples of the imidazole derivative compounds (general formulas (1) to (32)) used in the present invention are shown below, but these are representative examples in consideration of ease of handling. It is not limited.

  The compounds shown below are the same as those having different substituents for the left and right imidazoles, and may be a mixture thereof.

  Moreover, as a positive charge control agent used for this invention, the phosphonium compound shown by following formula (IX) is used preferably.

  When the phosphonium compound is used as the charge control agent, the content in the toner is 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass, per 100 parts by mass of the binder resin. The addition amount of the positive charge control agent is preferably 0.5 to 10 parts by mass because the colorant is finely and uniformly dispersed in the binder resin and the triboelectric chargeability of the toner is adjusted to a suitable range. When the addition amount of the positive charge control agent is less than 0.5 parts by mass, the positive charge control effect of the positive toner is reduced. When the addition amount of the charge control agent is more than 10 parts by mass, the toner is likely to be charged up under low temperature and low humidity.

  The toner according to the present invention includes a fatty acid metal salt (for example, zinc stearate, aluminum stearate, etc.) as a lubricant, a fluorine-containing polymer fine powder (for example, polytetrafluoroethylene, polyvinylidene fluoride, etc.) and tetrafluoro if necessary. A fine powder of an ethylene-vinylidene fluoride copolymer) or a conductivity imparting agent such as tin oxide or zinc oxide may be added.

  Furthermore, in the present invention, the toner may contain a release agent. Examples of release agents include aliphatic hydrocarbon waxes, oxides of aliphatic hydrocarbon waxes, ester waxes, waxes based on fatty acid esters, saturated linear fatty acids, unsaturated fatty acids, saturated Examples include alcohols, polyhydric alcohols, fatty acid amides, saturated fatty acid bisamides, unsaturated fatty acid amides, and aromatic bisamides.

  The content of the release agent in the toner is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin. When the content of the release agent exceeds 20 parts by mass, the blocking resistance and the high temperature offset resistance are liable to decrease. When the content is less than 0.1 parts by mass, the release effect tends to be small.

  These release agents are usually a method in which a binder resin is dissolved in a solvent, the temperature of the resin solution is increased, and the release agent is added and mixed while stirring, or a toner constituent material containing at least a binder resin and a colorant The binder resin is desirably contained by a method of mixing a release agent at the time of kneading.

  The toner can be produced by a method obtained by dispersing other toner constituent materials such as a colorant in a binder resin solution and then spray drying. In the present invention, the weight average particle diameter (D4) of the toner is 4.0 to 10.0 [mu] m, preferably 5.0 to 9.0 [mu] m. When the weight average particle diameter (D4) of the toner is less than 4.0 μm, it becomes difficult to achieve charging stabilization, and fog and toner scattering are likely to occur in durability. When the weight average particle diameter (D4) of the toner exceeds 10.0 μm, the reproducibility of the halftone portion is greatly deteriorated, and the obtained image tends to be a rough image. The weight average particle diameter of the toner can be adjusted to the above range by adjusting the direction of pulverization and classification.

  In the toner of the present invention, it is desirable to add an inorganic fine powder such as a fluidity improver as an external additive for the purpose of improving the fluidity of the toner. Any fluidity improver can be used as long as the fluidity can be increased by comparison between before and after the addition. For example, silicate fine powder, alumina fine powder, titanium oxide fine powder, zirconium oxide fine powder, magnesium oxide fine powder, fine powder of metal oxide such as zinc oxide; boron nitride fine powder, aluminum nitride fine powder, fine powder Nitrides such as fine powders of carbonized carbon; and calcium titanate, strontium titanate, barium titanate, magnesium titanate and the like.

  The external additive is usually used in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of the toner particles.

  In the present invention, it is particularly preferable to use a hydrophobized inorganic fine powder having an average primary particle size of 0.001 to 0.2 μm. The inorganic fine powder not only enhances the fluidity of the toner, but also does not hinder the chargeability of the toner. Therefore, in the toner of the present invention, it is preferable that the inorganic fine powder is subjected to a surface hydrophobization treatment with a hydrophobizing agent, and it is possible to satisfy both the provision of fluidity and the stabilization of charging at the same time. In other words, the hydrophobization treatment eliminates the influence of moisture, which is a factor that affects the amount of charge, and improves the environmental characteristics by reducing the difference in charging ability under high and low humidity. In addition, it is possible to prevent the primary particles from agglomerating by adding a hydrophobizing treatment in the manufacturing process, and it is possible to uniformly charge the toner. Further, the fine titanium oxide powder or the fine alumina powder in the present invention preferably has an average primary particle size of 0.001 to 0.2 μm, more preferably 0.005 to 0.1 μm from the viewpoint of imparting fluidity.

  When the average primary particle size is larger than 0.2 μm, the fluidity is lowered. When the average primary particle size is smaller than 0.001 μm, the toner is easily embedded in the toner surface, and the durability of the toner is likely to be lowered. This tendency is more remarkable when applied to a color toner having sharp melt properties. On the other hand, if it is smaller than 0.001 μm, the activity of the inorganic fine powder itself is inevitably high, and the particles tend to aggregate, making it difficult to obtain the desired high fluidity. The particle size of the inorganic fine powder in the present invention can be measured with a transmission electron microscope.

The hydrophobizing agent used in the present invention may be appropriately selected according to the purpose of surface modification, for example, control of charging characteristics, and stabilization and reactivity of charging under high humidity. Among these, a silane coupling agent having a substituent containing a nitrogen atom in the side chain, a titanium coupling agent, and a surface treated with silicone oil are preferable from the viewpoint of imparting positive charge.
Any conventionally known coupling agent having a substituent containing a nitrogen atom in the side chain can be used, and among them, a silane coupling agent and a titanium coupling agent are preferable.

  The silane coupling agent and the titanium coupling agent generally have structures represented by R′mSi—Zn and R′mTi—Zn, respectively, where R ′ is an alkoxy group or a halogen atom, and Z is an amino group. M and n are integers of 1 to 3, and m + n = 4.) The substituent containing a nitrogen atom is preferably an amino group. As the amino group, any of primary amine, secondary amine, tertiary amine and quaternary amine may be used. For example, the following are listed.

  A coupling agent having a substituent containing a nitrogen atom in the side chain, a coupling agent not having a substituent containing a nitrogen atom in the side chain, silicone oil, and hexamethyldisilazane react on the surface. Those adsorbed and adhered are also preferably used.

Preferably 0.1~500m ² / g as a specific surface area of these particles, more preferably 0.5~450m ² / g, and more preferably it has a 1~400m ² / g.

  Moreover, as a processing amount with respect to particle | grains, it is preferable that it is 0.1-70 weight part with respect to 100 weight part of particle | grains.

  In the present invention, the two-component non-magnetic developer described above is used for the toners of yellow, magenta, and cyan, but the one-component magnetic developer is used for the black toner. Although the toner used in the present invention has been described above, the same applies to the black toner. However, since black toner is a magnetic toner, it may have characteristics that are not found in other toners, or may have different preferable characteristics from other toners. Therefore, the black toner used in the present invention will be particularly described below.

  The particle size of the magnetic one-component black toner used in the present invention is 4 to 10 μm, preferably 5 to 9 μm, like the color toner described above. If the particle size is smaller than 4 μm, the image quality may be deteriorated because it is partially charged with an excessive charge from the three and the uniform coating is impaired. In addition, due to the presence of excessively charged particles in the sleeve lower layer, frictional charging of other particles is hindered and it cannot respond faithfully to the developing electric field, and as a result, white background fog tends to occur. This phenomenon is remarkable in a low-humidity environment where the toner is highly charged.

  On the other hand, if the particle size is larger than 10 μm, dot reproducibility is lowered, which is not preferable. As a particularly preferable form, it is preferable that the diameter is larger than the color toner particle size of yellow, magenta and cyan within a range of 2 μm or less. Since the frequency of use for black and white images is high, it is preferable to have a large particle size with high durability stability of development, transfer and fixing. However, if it is too large, not only the dot reproducibility with a single black color is inferior, but also the balance of image quality with a color image is greatly different, which is not desirable. Therefore, it is preferable that it is larger than the color toner particle diameter within a range of 2 μm.

  In addition, the positively chargeable charge control agent for the magnetic one-component black toner used in the present invention is not limited to those that can be used for two-component color toners, and is not limited by the color of the material itself. All control agents can be used.

  In addition, known materials can be used as the magnetic material contained in the magnetic one-component black toner used in the present invention, and particularly suitable magnetic materials include triiron tetroxide (Fe 3 O 4) or γ-iron sesquioxide (γ-Fe 2 O 3). ).

The magnetic properties of the magnetic particles of the magnetic one-component black toner used in the present invention are such that the saturation magnetization at 796 kA / m is 50 to 100 Am ² / kg, more preferably 65 to 90 Am ² / kg, and the residual magnetization is 2 to 2 It is good that it is 30 Am < ² > / kg, More preferably, it is 4-20 Am < ² > / kg.

If the saturation magnetization is smaller than 50 Am ² / kg, it becomes impossible to receive the magnetic regulation force from the sleeve, and thus fogging to the non-image area tends to increase. On the other hand, if the saturation magnetization is greater than 100 Am ² / kg, the magnetic regulation force from the sleeve is excessively increased, which makes it difficult for the toner to fly to the photoreceptor, resulting in a low image density, which is not preferable. Further, if the remanent magnetization is smaller than ² Am ² / kg, the fog to the non-image area is increased, which may cause a problem. Conversely, if the remanent magnetization is larger than 30 Am ² / kg, it may occur in the developing unit. This is not preferable because toner aggregation is large, mixing property after toner replenishment becomes insufficient, and image density is lowered.

  The content of the magnetic material in the magnetic one-component black toner is preferably 50 to 130 parts by weight, more preferably 60 to 110 parts by weight with respect to 100 parts by weight of the binder resin. When the amount is less than 50 parts by weight, the magnetic regulation force from the sleeve is weakened, so that the fog tends to deteriorate. In addition, uniform coating on the sleeve may be a problem. On the other hand, when the amount is more than 130 parts by weight, the magnetic restraint force is too strong, so that a sufficient image density may not be obtained.

  In order to fully develop the characteristics of the magnetic one-component black toner, it is preferable to use the inorganic fine powder described above. In particular, it is preferable to use two kinds of inorganic fine powders in order to improve the charging property, drum lubrication and polishing properties.

  As the metal oxide (A) in the inorganic fine powder, fluidizing agents such as silica, titanium oxide, and alumina are preferable. Among them, silica is the best for improving the chargeability. The content in the toner is 0.3 to 1.8 parts by weight, preferably 0.5 to 1.3 parts by weight. When the amount is less than 0.3 part by weight, the fluidity of the toner becomes insufficient and good charging characteristics cannot be obtained, so that problems such as a decrease in image density and occurrence of fog tend to occur. On the other hand, when the amount is more than 1.8 parts by weight, abnormal charging due to the charging property of the inorganic fine powder is caused, the uniform coatability to the sleeve is impaired, and the image quality and fogging tend to be deteriorated. Therefore, it is not preferable.

  Further, as the inorganic fine powder (B), silicon, titanium, strontium, manganese, zinc, cobalt, nickel, cerium, aluminum, barium, calcium, A composite metal compound selected from metals such as zirconium is preferred. Of these, strontium titanate is desirable.

  The weight average particle diameter of the inorganic fine powder (B) is 0.4 to 5 μm, preferably 0.7 to 3 μm. If it is smaller than 0.4 μm, the inorganic fine powder (B) is deposited on the lower layer of the sleeve to prevent the toner from being overcharged, but conversely causes the fog in a low humidity environment to inhibit the toner charging property. Sometimes. On the other hand, if it is larger than 5 μm, the effect of preventing the toner from being excessively charged in a low humidity environment cannot be suitably exhibited, and the uniform coatability of the sleeve tends to be impaired and fogging tends to occur.

  Moreover, the addition amount of inorganic fine powder (B) is 0.1-5 weight part, More preferably, 0.5-4 weight part is good. When the amount is less than 0.1 part by weight, the image density is lowered, the uniform coatability of the sleeve in a low humidity environment is lost, and further, the image flow is likely to occur in a high humidity environment. On the other hand, when the amount is more than 5 parts by weight, the chargeability of the toner is hindered, and fogging tends to increase in a low humidity environment.

  Examples of the magnetic carrier used in the two-component developer of the present invention include, for example, surface oxidized or unoxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth, and their magnetic alloys or magnetic oxidation. And magnetic ferrite. Furthermore, a binder-type carrier in which magnetic powder is dispersed in a resin can also be used. In the present invention, it is preferable to use a coated carrier in which the above-described magnetic carrier is used as a carrier core and the surface of the carrier core is covered with a coating material. In particular, a highly magnetically dispersed resin carrier is most preferred.

  In a coated carrier, the method of coating the surface of the carrier core with a coating material includes a method in which the coating material is dissolved or suspended in a solvent and applied to the carrier core, or a method of simply mixing in a powder state. Applicable.

  Examples of the carrier core coating material include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, acrylic resin, polyamide, polyvinyl butyral, and aminoacrylate resin. These may be used alone or in plural.

  Although the processing amount of the said material should just be determined suitably, Preferably it is 0.1-30 mass% (preferably 0.5-20 mass%) with respect to the resin coating carrier.

Further, in order to stabilize the positive chargeability of the toner in the coating material, it is more preferable to disperse a negatively charged additive in the carrier coating material. Alternatively, it is also effective to use a resin containing a negatively charged substituent such as fluorine as a coating material or to disperse it in the coating material.
As the negatively chargeable additive, a negative charge control agent such as a ditertiary butylsalicylic acid compound of aluminum, a ditertiary butylsalicylic acid compound of chromium, an azo iron metal complex, or the like can be used. Examples of the resin containing a fluorine-containing substituent include fluorine-modified acrylic, polytetrafluoroethylene, polyvinylidene fluoride, and copolymers thereof.

  The carrier used in the present invention preferably has a 50% volume average particle size of 10 to 80 μm, more preferably 20 to 70 μm.

  When the 50% volume average particle size of the carrier is less than 10 μm, the packing of the two-component developer is strengthened, the mixing property of the toner and the carrier is lowered, the toner chargeability is difficult to be stabilized, and the carrier Adhesion to the surface of the photosensitive drum is likely to occur. When the 50% volume average particle size of the carrier exceeds 80 μm, the chance of contact with the toner is reduced, so that low-charge toner is mixed and fogging is likely to occur. Furthermore, since toner scattering tends to occur, it is necessary to lower the toner concentration setting in the two-component developer, and it may be impossible to form an image with a high image density.

  As a particularly preferred carrier, the surface of the magnetic core particle of a magnetic material dispersion type resin carrier in which magnetite and hematite are bound with a phenol resin is coated with a resin such as a silicone resin, a fluorine resin, a styrene resin, an acrylic resin, and a methacrylate resin. What was covered with the material is preferable. The coating resin is added in an amount of 0.01 to 5% by mass, preferably 0.1 to 1% by mass with respect to the carrier core, and more than 70% by mass of 250 mesh pass and 400 mesh on carrier particles are added. In addition, a magnetic carrier whose particle size distribution is adjusted so as to have the 50% volume average particle size is preferable.

  As a method of adjusting the magnetic carrier so as to have the above 50% volume average particle size and a specific particle size distribution, for example, classification can be performed by using a sieve. In particular, in order to classify with high accuracy, it is preferable to repeat several times using a sieve having an appropriate mesh size. It is also effective to use a mesh whose shape is controlled by plating or the like.

When a two-component developer is prepared by mixing a toner and a magnetic carrier, the mixing ratio is 2 to 15% by mass, preferably 3 to 13% by mass, more preferably 4 to 4% as the toner concentration in the developer. When it is 10% by mass, good results are usually obtained. If the toner concentration is less than 2% by mass, the image density tends to be low, and if it exceeds 15% by mass, fogging or in-machine scattering tends to occur and the useful life of the developer tends to be shortened. The magnetic carrier preferably has a saturation magnetization of 20 to 80 Am ² / kg (emu / g).

<3> Measuring Method of Physical Properties in the Present Invention Next, measuring methods of physical properties will be described below. The same measurement was performed in the examples described later.

(1) Measurement of toner particle size distribution As a measuring device, for example, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) can be used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of toner particles are measured for each channel by using the 100 μm aperture as the aperture. Thus, the toner volume distribution and number distribution are calculated. Then, the weight-based toner weight average particle diameter (D4) obtained from the volume distribution of the toner particles (the median value of each channel is a representative value for each channel) is obtained.

  As channels, 2.00 to 2.52 μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm; 4.00 to 5.04 μm; 5.04 to 6.35 μm; 6.35 to 8. 00 μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32.00 μm; 13 channels of 32.00-40.30 μm are used.

(2) Method for measuring 50% volume average particle size of magnetic carrier For the average particle size and particle size distribution of magnetic carrier, dry dispersion unit RODOS (manufactured by JEOL) is combined with laser diffraction particle size distribution measuring device HEROS (manufactured by JEOL). As shown in Table 1, the range of the particle size of 0.5 μm to 350.0 μm is divided into 31 channels under the measurement conditions of lens focal length 200 mm, dispersion pressure 3.0 × 105 Pa, measurement time 1 to 2 seconds. It is possible to measure and obtain the 50% volume average particle diameter (median diameter) of the volume distribution as the average particle diameter, and obtain the volume% of particles in each particle diameter range from the volume-based frequency distribution.

  The laser diffraction particle size distribution measuring device HEROS used for measuring the particle size distribution is a device that performs measurement using the Franhofer diffraction principle. Briefly explaining this measurement principle, when a laser beam is irradiated onto a measurement particle from a laser light source, a diffraction image is formed on the focal plane of the lens on the opposite side of the laser light source, and the diffraction image is detected by a detector and calculated. By processing, the particle size distribution of the measurement particles is measured.

(3) Measuring method of magnetic property of magnetic carrier The magnetic property of the magnetic carrier can be measured using a BHU-60 type magnetization measuring device (RIKEN measuring machine). About 1.0 g of the measurement sample is weighed and packed in a cell having an inner diameter of 7 mmφ and a height of 10 mm, and set in the above-mentioned apparatus. In the measurement, an applied magnetic field is gradually applied and the maximum magnetic field is changed to 238.8 kA / m (3 k Oersted). Next, the applied magnetic field is decreased, and finally a hysteresis curve of the sample is obtained on the recording paper. Thus, saturation magnetization can be obtained.

(4) Measuring method of glass transition temperature of binder resin In this invention, it can measure using a differential thermal analysis measuring device (DSC measuring device) and DSC-7 (made by Perkin Elmer).

  The sample to be measured is precisely weighed 5 to 20 mg, preferably 10 mg.

  This is put into an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a measurement temperature range of 30 ° C. to 200 ° C., a temperature increase rate of 10 ° C./min, and normal temperature and humidity. In this temperature raising process, an endothermic peak of the main peak in the temperature range of 40 to 100 ° C. is obtained.

  At this time, the point of intersection between the base line midpoint before and after the endothermic peak and the differential heat curve is defined as the glass transition temperature Tg in the present invention.

(5) Method for measuring softening point temperature of toner The softening point temperature can be measured using, for example, a flow tester CFT-500 (manufactured by Shimadzu Corporation). The sample weighs about 1.0 g of a 60 mesh pass product. This is pressurized with a molding machine at a load of 100 kg / cm ² for 1 minute.

  The pressure sample is subjected to flow tester measurement under the following conditions under normal temperature and humidity (temperature of about 20 to 30 ° C., humidity of 30 to 70% RH) to obtain a temperature-apparent viscosity curve.

  From the obtained smooth curve, the temperature (= T1 / 2) when the sample flows out by 50% by volume is obtained, and this is defined as the softening point temperature Tm of the toner.

RATE TEMP 6.0 (° C / min)
SET TEMP 50.0 (° C)
MAX TEMP 180.0 (° C)
INTERVAL 3.0 (° C)
PREHEAT 300.0 (seconds)
LOAD 20.0 (kg)
DIE (Diameter) 1.0 (mm)
DIE (Length) 1.0 (mm)
PLUNGER 1.0 (cm ² )

(6) Measuring method of molecular weight of binder resin Mn, Mw, and Mw / Mn of the binder resin can be measured by gel permeation chromatography (GPC). The column is stabilized in a 40 ° C. heat chamber. Tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml per minute, and about 100 μl of THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, a standard polystyrene sample having a molecular weight of about 100 to 10000000 manufactured by Tosoh Corporation or Showa Denko is used, and it is appropriate to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector. As the column, it is preferable to use a combination of a plurality of commercially available polystyrene gel columns.

For example, a combination of Shoed GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK, TSKgel G1000H (H _XL ), G2000H (H _XL ), G3000H (H _XL ) manufactured by Tosoh Corporation ), G4000H (H _XL ), G5000H (H _XL ), G6000H (H _XL ), G7000H (H _XL ), and TSK guard column.

  The sample is prepared as follows.

  Place the sample in THF and let stand for several hours, then shake well and mix well with THF (until the sample is no longer united) and let stand for more than 12 hours. At this time, the standing time in THF is set to be 24 hours or longer. Thereafter, a sample processing filter (pore size 0.45 to 0.5 μm, for example, Mysori Disc H-25-5 manufactured by Tosoh Corporation, Excro Disc 25CR, Gelman Science Japan Co., Ltd., etc. can be used) is passed. A sample of GPC. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

(7) Method for measuring acid value The acid value can be measured as follows.

2-10 g of sample is weighed into a 200-300 ml Erlenmeyer flask, and about 50 ml of a mixed solvent of methanol: toluene = 30: 70 is added to dissolve the resin. If solubility is poor, a small amount of acetone may be added. Using a mixed indicator of 0.1% bromthymol blue and phenol red, titration is performed with a pre-standardized N / 10 caustic potash to alcohol solution, and the acid value is obtained from the consumption of the alcohol potash solution by the following calculation.
Acid value = KOH (ml) x N x 56.1 / sample weight (where N is a factor of N / 10 KOH)

(8) Method for measuring D0.5 The contrast potential of the main body and other development conditions are adjusted so that the toner loading on the unfixed transfer material is 0.5 mg / cm ² . Thereafter, under the same conditions, the image is usually fixed through a fixing device, and the image density is measured. For measurement of image density, a 404 type reflection densitometer manufactured by X-Rite can be used.

(9) Method for Measuring BET Specific Surface Area of Inorganic Fine Powder Using a fully automatic gas adsorption amount measuring device Autosorb 1 manufactured by Yuasa Ionics Co., Ltd., nitrogen is used as the adsorption gas, and the BET multipoint method is used. In addition, deaeration for 10 hours is performed at 50 degreeC as pre-processing of a sample.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the present experimental example.

<Production of photoconductor>
(1) Preparation of a-Si photoconductor Table 2 was prepared on an aluminum cylinder subjected to mirror finishing with a diameter of 60 mm using the same apparatus for manufacturing a photoconductor for an image forming apparatus by RF-PCVD as shown in FIG. A positively charged photoconductor was prepared under the conditions shown in Table 3, and a negatively charged photoconductor was prepared under the conditions shown in Table 3.

  Hereinafter, the photoconductor produced by the method of Table 2 is referred to as a-Si photoconductor 1, and the photoconductor produced by the method of Table 3 is referred to as a-Si photoconductor 2.

  Moreover, what was created by the method of Table 2 using the aluminum cylinder of diameter 15, 20, 40, 80, and 100 mm is set to a-Si photoreceptor 3-7.

<Manufacture of binder resin>
(1) Production of binder resin 1
・ Polyoxypropylene (2,2) -2,2bis (4-hydroxyphenyl) propane 14 mol%
・ Polyoxyethylene (2,2) -2,2 bis (4-hydroxyphenyl) propane 34 mol%
・ Terephthalic acid 15mol%
・ Fumaric acid 36mol%
・ Trimellitic acid 1mol%
These were charged into a four-necked flask, and equipped with a reflux condenser, a water separator, a nitrogen gas introduction tube, a thermometer and a stirring device, and subjected to condensation polymerization while introducing nitrogen into the flask.

  Furthermore, 490 parts by mass of xylene and 110 parts by mass of the polyester resin were charged into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introduction tube, a reflux tube, and an isocyanate compound dropping device. The polyester resin was dissolved in xylene by heating with stirring. A xylene solution containing 5 parts by mass of diphenylmethane-4,4 'diisocyanate was added dropwise in a constant amount over 1.5 hours under reflux of xylene. After completion of the dropwise addition, stirring was continued for another hour to complete the reaction. By distilling off xylene, a urethane-modified polyester resin (1) as a binder resin was obtained.

  Condensation polymerization similar to that of the polyester resin (1) was carried out by appropriately changing the constituent components and the blending amounts to obtain polyester resins (2) to (6). Table 4 shows the physical properties of the obtained resin and the monomers used.

(2) Production of binder resin 2
Styrene 75 parts by mass n-butyl acrylate 25 parts by mass Mono-n-butyl malate 10 parts by mass Divinylbenzene 0.3 parts by mass Benzoyl peroxide 1.2 parts by mass 170 parts by mass of water in which 12 parts by mass were dissolved was added and stirred vigorously to obtain a suspension polymerization solution. The above suspension dispersion was added to a reactor having 300 parts by mass of water and purged with nitrogen, and subjected to suspension reaction polymerization. After completion of the reaction, the product was washed with water and dehydrated, followed by drying at 40 ° C. for 24 hours to obtain a vinyl resin (7).

  As shown in Table 4, this resin (7) had an acid value of 13.4, Tg: 63 ° C., Mn: 6100, and Mw: 18900.

<Production of toner>
(1) Preparation of yellow toner Using the toner shown in Table 5, a yellow toner was prepared as follows. The physical properties of the obtained yellow toner are also shown in Table 5.

(1-1) Preparation of yellow toners Y1 to Y18, polyester resin (1) 70 parts by mass, paste pigment 100 parts by mass (CI Pigment Yellow 180 was produced by a known method. That is, a filtration step. A certain amount of water was removed from the previous pigment slurry, and a paste pigment with a fixed content of 30% by mass (the remaining 70% by mass was water) obtained without going through a drying process.)
First, the above raw materials are charged into a kneader type mixer according to the above formulation, and the temperature is raised under no pressure while mixing. When the maximum temperature (necessarily determined by the boiling point of the solvent in the paste. In this case, about 90 to 100 ° C.) is reached, the pigment in the aqueous phase is distributed or transferred to the molten resin phase, and this is confirmed. Then, the mixture is further melted and kneaded for 40 minutes to sufficiently transfer the pigment in the paste. Then, once the mixer was stopped and the hot water was discharged, the temperature was further raised to 140 ° C., heated and kneaded for about 40 minutes, the pigment was dispersed and the water was distilled off, and the process was completed. The first kneaded product was taken out. The water content of this final kneaded product was about 0.7% by mass.

-20.0 parts by mass of the first kneaded product (pigment particle content 30% by mass)-86.0 parts by mass of polyester resin (1)-Quaternary ammonium salt ("VP2036" manufactured by Hoechst (melting point: 200 ° C) )) 4.0 parts by mass The above formulation was sufficiently premixed with a Henschel mixer, melt-kneaded at a temperature of 130 ° C. with a twin-screw extruder kneader to obtain a second kneaded product, a hammer mill after cooling Was roughly pulverized to about 1 to 2 mm, and then pulverized to a particle size of 38 μm or less by an air jet type pulverizer. Further, the obtained finely pulverized product is classified and selected so that the weight average particle size in the particle size distribution is 8.0 μm to obtain yellow toner particles (classified product) for the purpose of improving fluidity and imparting charging characteristics. Then, 1.0 part by mass of titanium oxide fine powder hydrophobized with an Si compound was externally added to 100 parts by mass of yellow toner particles to obtain yellow toner (Y1). The external additives used are shown in detail in Tables 8-1 and 8-2.

  Next, yellow toners Y2 to Y12, Y17, and Y18 were prepared in the same manner except that the type of pigment as a colorant and the amount of the pigment added were changed.

  Next, yellow toners Y13 to Y16 having different toner particle sizes were obtained in substantially the same manner as the yellow toner Y1, except that the pulverization classification conditions (winding pressure of the pulverizer, airflow of the classifier) and the amount of the external additive were changed.

(1-2) Preparation of yellow toners Y19 and Y20 / Polyester resin (1) 70 parts by mass / C.I. I. Pigment Yellow 180 30 parts by mass The above raw materials are charged into a kneader-type mixer, heated while being mixed with no pressure, and sufficiently premixed. Thereafter, the mixture was kneaded twice with three rolls to obtain a first kneaded product.
-26.7 parts by weight of the first kneaded product-81.3 parts by weight of polyester resin (1)-4 parts by weight of quaternary ammonium salt The above formulation is sufficiently premixed with a Henschel mixer and melted with a twin screw extruder. The mixture was kneaded to obtain a second kneaded product, and then yellow toner Y19 was obtained in the same manner as yellow toner Y1. Similarly, yellow toner Y20 was obtained with the pigment content of 4 parts by mass.

(1-3) Preparation of yellow toner Y21 / Polyester resin (1) 100 parts by mass / C.I. I. Pigment Yellow 180 4 parts by mass, quaternary ammonium salt 4 parts by mass The above formulation is sufficiently premixed with a Henschel mixer, melt-kneaded with a twin screw extruder, and then yellow toner Y21 is prepared in the same manner as yellow toner Y1. Obtained.

(1-4) Preparation of Yellow Toner Y22 The first kneaded product (pigment particle content 30% by mass) prepared with Yellow Toner Y1 was further kneaded five times with three rolls to further sufficiently disperse the pigment. In the same manner from the second kneading step, yellow toner Y22 was obtained.

(2) Preparation of magenta toner (2-1) Preparation of magenta toners M1 to M16 The first toner toner Y1 was prepared in substantially the same manner as the yellow toner Y1, except that a magenta pigment paste pigment as a colorant described in Table 6 was used. After obtaining the kneaded material, it was diluted and kneaded so as to obtain the desired pigment content to obtain a second kneaded material, and then magenta having a weight average particle diameter of 7.5 μm as in the production of the yellow toner Y1. Toners M1 to M16 were obtained.

(3) Preparation of cyan toner (3-1) Preparation of cyan toners C1, C2 and C4 to C6 Except for using a cyan pigment paste pigment as a colorant described in Table 7, it is almost the same as yellow toner Y1. After the first kneaded product is obtained, the mixture is diluted and kneaded so as to obtain a desired pigment content to obtain a second kneaded product, and then the weight average particle size is 6 as in the production of the yellow toner Y1. Cyan toners C1 and C2 of 0.0 to 8.0 μm were obtained. Further, the external additive was changed from titanium oxide A shown in Table 8-1 to alumina A and produced in the same manner as yellow toner Y1, and C4 to C6 were obtained.

(3-2) Preparation of Cyan Toner C3 C3 was produced in substantially the same manner as the yellow toner Y21 except that the pigment used as the colorant was changed.

That is, the following raw materials were sufficiently premixed with a Henschel mixer, melted and kneaded with a twin-screw extruder, and cyan toner C3 shown in Table 7 was obtained in substantially the same manner as in the production of yellow toner Y21.
-Polyester resin (1) 100 parts by mass-C.I. I. Pigment Blue 15: 3 2 parts by mass / quaternary ammonium salt 4 parts by mass

(3-3) Preparation of cyan toners C7 to C9 Other than using an imidazole compound, an ammonio group-containing styrene acrylic copolymer resin, or a quaternary ammonium salt and an imidazole compound instead of the charge control agent used in cyan toner C1. Obtained cyan toners C7 to C9 shown in Table 7 in the same manner as in the production of cyan toner C1.

(3-4) Preparation of Cyan Toners C10 to C15 Except for using Resin (2) to Resin (7) instead of Resin (1) used in Cyan Toner C1, the same procedure as in Cyan Toner C1 was made. Thus, cyan toners C10 to C15 shown in Table 7 were obtained.

(4) Preparation of black toner <Example of preparation of black toner>
Polyester resin (8) 100 parts by mass Magnetic particles (ii) 85 parts by mass Quaternary ammonium salt 4 parts by mass Low molecular weight polypropylene 5 parts by mass After sufficiently premixing the above materials with a Henschel mixer (Mitsui Mine Co., Ltd.), 130 Melt kneading was performed by a twin screw extruder at 0 ° C. The kneaded product was allowed to cool, then coarsely pulverized by a cutter mill, pulverized using a fine pulverizer using a jet stream, and further classified using air classification to obtain a magnetic black toner. To 100 parts by mass of this magnetic toner, 0.9 part by mass of silica B and 3 parts by mass of composite metal oxide (B) -1 were externally added by a Henschel mixer, and a magnetic material having a weight average particle size of 8.1 μm. A black toner Bk1 was obtained.

<Preparation Example of Black Toner Bk2-10>
The black toners Bk2 to 10 shown in Table 9 are substantially the same as the black toner Bk1 except that the black magnetic particles (b) to (n) are used instead of the magnetic particles (b) used in the black toner Bk1. Got.

<Examples of black toners Bk11 and Bk12>
Black toners Bk11 and Bk12 shown in Table 9 were obtained in the same manner except that the added parts of the magnetic particles (A) used in the black toner Bk1 were changed to 60 parts and 110 parts, respectively.

<Examples of black toners Bk13 and Bk14>
Black toners Bk13 and Bk14 shown in Table 9 were obtained in the same manner except that the amount of silica B used in black toner Bk1 was changed to 0.2 parts and 2.0 parts, respectively.

<Examples of black toners Bk15 and Bk16>
Except that the amount of the inorganic fine powder (B) -1 used in the black toner Bk1 is changed to 0.05 parts and 5.2 parts, respectively, the rest is the same as described in Tables 9 and 10. Toners Bk15 and Bk16 were obtained.

<Examples of black toners Bk17 to Bk20>
The black toner Bk17 shown in Table 10 is similarly used except that the particle size of the toner is changed to 3.8 μm, 5.5 μm, 9.4 μm, and 10.8 μm by changing the pulverization classification conditions when the black toner Bk1 is produced. ~ Bk20 was obtained.

<Examples of black toners Bk21 and Bk22>
Black toners Bk21 and Bk22 shown in Table 10 were obtained in the same manner except that the type of silica B used in the black toner Bk1 was changed to titanium oxide A and alumina A.

<Example of production of black toners Bk23 to Bk27>
The type of the inorganic fine powder (B) -1 used in the black toner Bk1 is changed to (B) -2, (B) -3, (B) -4, (B) -5, (B) -6. In the same manner, black toners Bk23 to Bk27 shown in Table 10 were obtained.

<Example of production of black toner Bk28>
A black toner Bk28 shown in Table 10 was obtained in the same manner except that the amount of the quaternary ammonium salt, which is the charge control agent used in the black toner Bk1, was changed to 5.5 parts by mass.

<Examples of black toners Bk29 and Bk30>
Black toners Bk29 and Bk30 shown in Table 10 were obtained in the same manner except that the type of binder resin used in black toner Bk1 was changed to resin (3) and resin (9), respectively.

(5) Preparation of carrier and developer: 50 parts of phenol (hydroxybenzene), 80 parts of a 37 wt% formalin aqueous solution, 50 parts of water, 280 parts of silane coupling agent having epoxy group KBM403 (manufactured by Shin-Etsu Chemical Co., Ltd.) ) Surface-treated alumina-containing magnetite fine particles (number average particle size 0.22 μm, specific resistance 4 × 10 ⁵ Ω · cm)
120 parts of α-Fe ₂ O ₃ fine particles surface-treated with KBM403 (number average particle diameter 0.40 μm, specific resistance 8 × 10 ⁹ Ω · cm)
-25 wt% ammonia water 15 parts The above materials were put into a four-necked flask, heated to 85 ° C for 60 minutes while stirring and mixed, and reacted and cured for 120 minutes. After cooling to 30 ° C. and adding 500 parts by weight of water, the supernatant was removed, the precipitate was washed with water and air-dried. Next, this was dried under reduced pressure (5 mmHg) at 150 to 180 ° C. for 24 hours to obtain a magnetic carrier core (A) having a phenol resin as a binder resin.

  The surface of the magnetic carrier core (A) thus obtained was diluted with toluene so that the fluoroacrylic resin had a solid content of 25%, and then 0.2 mass% was added to the core particles under reduced pressure to perform resin coating. It was. Thereafter, after stirring for 2 hours, heat treatment was performed at 140 ° C. for 2 hours in an atmosphere of nitrogen gas to loosen the agglomerates, and then coarse particles of 200 mesh or more were removed to obtain a magnetic carrier 1.

  The carrier 1 had a 50% volume average particle size of 40 μm.

  Next, the particle diameter was changed by the core agent type, the coating material, and the production conditions (stirring conditions), and Carriers 2 to 7 were produced. Table 11 shows the production method, carrier particle size, and the like.

  The carrier is mixed with 5 parts by mass of the toner obtained above so that the total amount becomes 100 parts by mass to obtain a two-component developer.

<Experimental example 1>
Evaluation of the image is performed by an experimental apparatus having the same structure as that of the image forming apparatus shown in FIG. 1 of the above embodiment and capable of producing full-color images of four colors including charging, exposure, development, transfer, cleaning, and charge removal. I did it.

  Yellow toner is arranged in the first image forming unit, magenta toner is arranged in the second image forming unit, cyan toner is arranged in the third image forming unit, and black toner is arranged in the fourth image forming unit. The positively charged photoconductors 1, 3, 4, 6, and 7 prepared above were used as the photoconductor.

  The peripheral speed (process speed: PS) of the photosensitive member was set to 200 mm / s, and the surface potential of the photosensitive member was set to 350 V in the developing region. The distance between the photosensitive member and the developing sleeve was 400 μm for the first, second, and third image forming units, and 250 μm for the fourth image forming unit. The developing sleeve was rotated at twice the peripheral speed of the photosensitive member. Image exposure was used for image formation. Regarding the toner, Y1 was used for yellow toner, M1 for magenta toner, C1 for cyan toner, and Bk1 for black toner. Carrier 1 was used as the color carrier.

  For image evaluation, the image density when only black toner was developed, the image density when only yellow toner was developed, and the image density of the yellow portion when developing four colors were examined. The results are shown in Table 12.

  When the photoreceptor 3 having a diameter of 15 mm was used, a surface potential of 350 V could not be obtained, and a high density image could not be obtained. For this reason, the peripheral speed of the photosensitive member was reduced to 100 mm / s and image output was performed at the same potential, but even in that case, a sufficient image could not be obtained.

  Further, when the photoconductor 7 having a diameter of 100 mm was used, a sufficient density was obtained in a single color, but when the image was printed in four colors, the image density of the image generated by the first image forming unit A decrease was seen. This is presumably because the toner on the transfer material was re-transferred onto the photoreceptor due to the increase in the diameter of the photoreceptor.

<Experimental example 2>
Using the experimental apparatus used in Experimental Example 1, an a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member to form an image. The charging potential is changed from 250 to 500 V, and the density difference between the exposure portion called a ghost and the specific exposure portion after one round when the image density in the black image, the reflection density is 0.6, and the reflection density is 0.6. I investigated. The results are shown in Table 13.

  When the surface potential was less than 300V, the image density was low. On the other hand, when the voltage was higher than 450 V, the variation in the density of the image having a reflection density of 0.3 deteriorated, and the drum ghost increased.

<Experimental example 3>
The a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member of the experimental apparatus used in Experimental Example 1, and the dependency on the minimum gap (SD gap) between the photosensitive member and the developing sleeve was evaluated. As the contents, the fusion and density of the photosensitive member were examined when 10,000 black images printed with 7% on the image were printed. The results for the magnetic toner are shown in Table 14 (1), and the results for the color toner are shown in Table 14 (2).

  When the SD gap was 350 μm for color toners and the SD gap was less than 80 μm for black toners, drum fusion occurred. Further, when the SD gap was larger than 800 μm for the color toner and the SD gap was larger than 510 μm for the black toner, a sufficient image density could not be obtained.

<Experimental example 4>
Using the experimental apparatus used in Experimental Example 1, an a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member, and the dependency on the peripheral speed ratio of the sleeve was evaluated. The peripheral speed of the sleeve is changed from 1.05 to 5 times the peripheral speed of the photosensitive member, and an image of black toner when an initial black image density and 50,000 black originals printed at 7% on the image are printed. The concentration was examined. The results are shown in Table 15.

  When the sleeve peripheral speed ratio was smaller than 1.1, a decrease in image density was observed from the beginning. When the sleeve peripheral speed ratio was greater than 4.0, the density decreased after the endurance of 50,000 sheets. Also, fog was generated and a good image could not be obtained.

<Experimental example 5>
Using the experimental apparatus used in Experimental Example 1, an a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member, and the dependency of the image quality on the toner particle size was evaluated. Yellow toners Y1 and Y13 to 16 were used. The results are shown in Table 16.

<Experimental example 6>
The a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member of the experimental apparatus used in Experimental Example 1, and the dependency of the image quality on the particle size of the carrier was evaluated. The results are shown in Table 17.

  When the carrier particle size was smaller than 10 μm, carrier adhesion to the image area was observed from the beginning of the durability, and when the carrier was smaller than 10 μm, the coating amount on the sleeve was not uniform and density unevenness was likely to occur. . On the other hand, when the carrier particle size was larger than 80 μm, the density of the spikes formed on the sleeve was coarse, and the spikes were generated in the halftone part, resulting in lack of image uniformity.

<Experimental example 7>
Using the experimental apparatus used in Experimental Example 1, the a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member, and the dependency on the coloring power of the toner was evaluated. The coloring power of the toner was evaluated based on the image density (D0.5) after normal fixing when the amount of unfixed toner (M / S) on the transfer material was M / S = 0.5 mg / cm ² . . Using yellow toners Y3 and Y17 to Y22 having different coloring powers, images of 16 gradations were produced with the respective toners, and the density and gradation were evaluated. The results are shown in 18.

  From the results shown in Table 18, when D0.5 is small, a sufficient image density cannot be obtained, and when D0.5 is larger than 1.8, there is a problem in density reproducibility of intermediate colors due to environmental changes.

<Experimental Example 8>
Using the experimental apparatus used in Experimental Example 1, the a-Si photosensitive member 1 having a diameter of 60 mm was used as the photosensitive member, and the dependency of the image on the binder resin of the toner was evaluated.

  Using toners C10 to C15 having different resins with respect to cyan toner C1, the transition in density at the initial stage and the endurance of 50,000 sheets in each resin at low temperature and low humidity (initial density → density at 50,000 sheets), high temperature The image quality and transparency of OHP in a high humidity environment were evaluated. The results are shown in Table 19.

<Example 1>
A positively charged photoconductor was produced on an aluminum cylinder having a mirror finish of 60 mm in diameter, using an apparatus for producing a photoconductor by RF-PCVD under the conditions shown in Table 1 above.

  The produced photoreceptor was mounted on a Canon copier CLC1000, and an image was evaluated using an experimental apparatus equipped with an intermediate transfer member. Note that the NP6085 developer was used as the fourth developing unit. Two-component cyan toner is used for the first image forming unit, two-component magenta toner is used for the second image forming unit, two-component yellow toner is used for the third image forming unit, and two-component yellow toner is used for the fourth image forming unit. A magnetic one-component black toner was disposed.

  The photoreceptor was rotated at a peripheral speed (process speed) of 140 mm / s. The surface potential of the photosensitive member was set to 410 V at the developing unit position. The distance between the photosensitive member and the developing sleeve was 460 μm for the first, second, and third image forming units, and 300 μm for the fourth image forming unit, and the developing sleeve was rotated at 1.8 times the peripheral speed of the photosensitive member. Image exposure was adopted for image formation, and the image forming conditions were set such that 31 images could be formed per minute.

  The toner used was Y1 for yellow toner, M1 for magenta toner, C1 for cyan toner, and BK1 for black toner.

When the unfixed toner amount (M / S) on each color transfer material is M / S = 0.5 mg / cm ² , the image density after normal fixing is D0.5Y: 1.41, D0.5M : 1.22, D0.5C: 1.31, and D0.5Bk: 1.01. The difference between the maximum value (D0.5max) and the minimum value (D0.5min) of D0.5Y, D0.5M, and D0.5C was 0.19.

  Table 20 shows the gloss difference for each color, the saturation of the color image, and the color reproducibility when the environment changes.

  In addition, the measuring method of the gross difference was measured with the following method.

  For measurement of gloss (glossiness), a VG-10 glossiness meter manufactured by Nippon Denshoku Co., Ltd. was used.

  For measurement, first set the voltage to 6V with a constant voltage device, then adjust the light projection angle and light reception angle to 60 °, use the zero point adjustment and the standard plate, and place the sample image on the sample stage after standard setting. Further, measurement was performed by superposing three white papers on top of each other, and the numerical value shown on the display unit was read in% units.

  Sample images are prepared for each of yellow, magenta, and cyan colors with an X-Rite 404-type reflection densitometer reading value of 1.50. After reading the gloss of each color, the maximum and minimum values are obtained. The difference in values was determined.

  Those having a difference in gloss of less than 3 were evaluated as ◎, those of 3 or more and less than 6 were evaluated as ◯, those of 6 or more and less than 10 were evaluated as Δ, and those of 10 or more were evaluated as ×. Further, the saturation of the color image was measured as follows.

  The saturation of the image is a value calculated by the following equation, and the larger C *, the brighter the image.

  When forming a full-color image, the larger the C * and spread for each color, the more vivid images can be reproduced for single colors and intermediate colors.

The color tone of the toner was quantitatively measured based on the color system definition defined by the International Commission on Illumination (CIE) in 1976. That is, a ^* , b ^* (a ^* , b ^* are chromaticities representing hue and saturation) and L * (lightness) were measured. A spectrocolorimeter type 938 manufactured by X-rite was used as the measuring instrument, the measurement light source was a C light source, and the viewing angle was 2 °.

Sample images were prepared for each of yellow, magenta, and cyan colors with an X-Rite 404-type reflection densitometer reading of 1.50. After reading a ^* and b ^* for each color, The color space that can be formed was determined and the color saturation was evaluated.

  Next, regarding the color reproducibility when a full-color image using three colors was formed, skin-color and green images were prepared and evaluated.

  For yellow, magenta, cyan, flesh, and green, images with good color reproducibility were obtained. ◎ Only one color was slightly saturated, but other colors were excellent for color reproducibility. A product having some difficulty in color reproducibility but having no problem in practical use was evaluated as Δ, and a product having difficulty in color reproducibility was evaluated as ×.

  The method for measuring the color reproducibility when the environment changed was as follows.

In a low-temperature and low-humidity environment (25 ° C./8%), L ^* (brightness) 55 to 65, a ^* and b ^* are a ^* : −2 to 2 and b ^* : −2 to 2 using yellow, magenta and cyan, respectively. 2, a gray image was formed. Without changing the setting conditions of the image forming apparatus, the environment was changed to a high temperature and high humidity environment (30 ° C./75%), and a gray image was printed.

  Regarding the gray color change, a good one with no color change was evaluated as ◯, a slight color change with a problem-free level was evaluated as Δ, and a clear color change was evaluated as X.

<Example 2>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M5 for magenta toner, and C2 for cyan toner.
The results are shown in Table 20.

<Example 3>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M10 for magenta toner, and C2 for cyan toner.
The results are shown in Table 20.

<Comparative Example 1>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M13 for magenta toner, and C2 for cyan toner.

  The results are shown in Table 20.

  As a result of evaluating the images, the gross difference between the colors was large, and a clear image could not be obtained. In addition, the control for density fluctuation due to environmental differences was severe, and density unevenness became severe due to environmental differences.

<Example 4>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M5 for magenta toner, and C4 for cyan toner.

  The results are shown in Table 20.

<Comparative example 2>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M5 for magenta toner, and C5 for cyan toner.

  The results are shown in Table 20.

  As a result of evaluating the images, there was a large gloss difference between the colors, and a clear image could not be obtained. In addition, the control for density fluctuation due to environmental differences was severe, and density unevenness became severe due to environmental differences.

<Example 5>
Image formation evaluation was performed in the same manner as in Example 1 except that Y18 was used for yellow toner, M13 for magenta toner, and C5 for cyan toner.

  The results are shown in Table 20.

<Example 6>
Image formation evaluation was performed in the same manner as in Example 1 except that Y18 was used for yellow toner, M1 for magenta toner, and C5 for cyan toner.
The results are shown in Table 20.

<Comparative Example 3>
Image formation evaluation was performed in the same manner as in Example 1 except that Y18 was used for yellow toner, M5 for magenta toner, and C5 for cyan toner.

  The results are shown in Table 20.

  As a result of evaluating the images, there was a large gloss difference between the colors, and a clear image could not be obtained. In addition, the control for density fluctuation due to environmental differences was severe, and density unevenness became severe due to environmental differences.

<Example 7>
Image formation evaluation was performed in the same manner as in Example 1 except that Y8 was used for yellow toner, M13 for magenta toner, and C5 for cyan toner.

  The results are shown in Table 20.

<Comparative example 4>
Image formation evaluation was performed in the same manner as in Example 1 except that Y5 was used for yellow toner, M13 for magenta toner, and C5 for cyan toner.

  The results are shown in Table 20.

  As a result of evaluating the images, there was a large gloss difference between the colors, and a clear image could not be obtained. In addition, the control for density fluctuation due to environmental differences was severe, and density unevenness became severe due to environmental differences.

<Example 8>
In the Canon copier CLC1000, an image was evaluated using an experimental apparatus modified to have an intermediate transfer member and having the same structure as the image forming apparatus shown in FIG. 1 of the above embodiment.

  Cyan toner is disposed in the first image forming unit, magenta toner is disposed in the second image forming unit, yellow toner is disposed in the third image forming unit, and black toner is disposed in the fourth image forming unit. The positively charged a-Si photosensitive member 5 manufactured as described above was disposed on the photosensitive member. The photosensitive member was rotated at a peripheral speed (process speed: PS) of 102 mm / s.

  The surface potential of the photosensitive member is set to 310 V in the developing region, the distance between the photosensitive member and the developing sleeve is 600 μm for the first, second, and third image forming units, and 200 μm for the fourth image forming unit. It was rotated at 1.5 times the body peripheral speed. An image forming apparatus capable of forming 23 images per minute using image exposure for image formation was produced.

  The results are shown in Table 20.

<Example 9>
In the Canon copier CLC1000, an image was evaluated using an experimental apparatus modified to have an intermediate transfer member and having the same structure as the image forming apparatus shown in FIG. 1 of the above embodiment.

  Cyan toner is disposed in the first image forming unit, magenta toner is disposed in the second image forming unit, yellow toner is disposed in the third image forming unit, and black toner is disposed in the fourth image forming unit. The positively charged a-Si photosensitive member 1 manufactured as described above was disposed on the photosensitive member. The peripheral speed (process speed: PS) of the photoreceptor was rotated at 300 mm / s.

  The surface potential of the photosensitive member is set to 380 V in the developing region, the distance between the photosensitive member and the developing sleeve is 460 μm in the first, second, and third image forming units, and 250 μm in the fourth image forming unit. It was rotated at 3 times the body speed. An image forming apparatus capable of forming 70 images per minute using image exposure for image formation was produced.

  As the toner, yellow toner was used as Y3, magenta toner as M3, cyan toner as C1, and black toner as Bk7. Carrier 7 was used as the magnetic carrier.

  The results are shown in Table 20.

<Examples 10 to 20>
Image formation evaluation was performed under the same conditions as in Example 1 except that the yellow toner was changed to Y2 to Y12. Table 21 shows the gloss difference for each color, the saturation of the color image, and the color reproducibility when the environment changes.

<Examples 21 to 35>
Image formation evaluation was performed under the same conditions as in Example 1 except that the magenta toner was changed to M2 to M16. Table 22 shows the gloss difference for each color, the saturation of the color image, and the color reproducibility when the environment changes.

<Examples 36 to 39>
Image formation evaluation was performed under the same conditions as in Example 1 except that the cyan toner was changed to C2 and C7 to C9. Table 23 shows the gloss difference for each color, the saturation of the color image, and the color reproducibility when the environment changes.

<Examples 40 to 61>
Image formation was performed under the same conditions as in Example 1 except that the black toner was changed to Bk2 to Bk16 and Bk21 to BkBk27. Table 24 shows the gloss difference for each color, the saturation of the color image, and the color reproducibility when the environment changes.

<Example 62>
Under the conditions shown in Table 2, a negatively charged photoconductor was produced on an aluminum cylinder having a mirror finish of 60 mm in diameter, using an apparatus for producing a photoconductor by RF-PCVD.

  The manufactured photoconductor was modified from Canon CLC1000, and images were evaluated using this experimental apparatus. Cyan toner is disposed in the first image forming unit, magenta toner is disposed in the second image forming unit, yellow toner is disposed in the third image forming unit, and black toner is disposed in the fourth image forming unit. .

  The photoreceptor was rotated at a peripheral speed (process speed) of 200 mm / s. The surface potential of the photosensitive member was set to -380 V at the developing unit position. The distance between the photosensitive member and the developing sleeve was 500 μm for the first, second, and third image forming units, and 300 μm for the fourth image forming unit, and the developing sleeve was rotated at 1.8 times the peripheral speed of the photosensitive member. Back scan exposure was adopted for image formation, and image forming conditions were set so that 50 images could be formed per minute.

  The toner used was Y1 for yellow toner, M1 for magenta toner, C1 for cyan toner, and BK1 for black toner.

  The results are shown in Table 24.

1 is a schematic explanatory view showing one embodiment of a full-color image forming apparatus using a color image forming method of the present invention. FIG. 2 is a schematic configuration diagram for explaining a layer configuration of a photoreceptor for an image forming apparatus according to the present invention. It is a figure which shows an example of the RF-PCVD apparatus for manufacturing the photoreceptor in this invention. It is a figure which shows an example of the VHF-PCVD apparatus for manufacturing the photoreceptor in this invention. FIG. 3 is a schematic diagram illustrating first to third image forming units in the image forming apparatus of the present invention. It is the schematic which shows the 4th image forming unit in the image forming apparatus of this invention.

Explanation of symbols

2 Blade 3 Developing sleeve 4 Photoconductor 9 Developing device 5, 10 Magnet 11, 12 Stirring screw 13 Developing chamber 14 Stirring quality 15 Power supply 21 Charging device 22 Light emitting element 23 Transfer charging device 24 Transfer paper 25 Fixing device 26 Cleaning device 1100 Photoconductor 1101 Conductive support 1102 Photosensitive layer 1103 Photoconductive layer 1104 Surface layer 1105 Charge injection blocking layer 1106 Charge generation layer 1107 Charge transport layer 2100, 3100 Deposition device 2111, 3111 Reaction vessel 2112, 3112 Cylindrical support 2113, 3113 Support Superheater 2114 Source gas introduction tube 2115 High-frequency matching box 2200 Source gas supply device 3130 Discharge space

Claims (28)

The first toner image formed by the first image forming unit, the second toner image formed by the second image forming unit, the third toner image formed by the third image forming unit, and the fourth toner image The fourth toner image formed by the image forming unit is transferred to the transfer material with or without the intermediate transfer member, and the transfer material having the first, second, third, and fourth toner images is transferred. An image forming method in which a full color image or a multicolor image is formed on a transfer material by conveying to a heat and pressure fixing means and performing heat and pressure fixing,
(A) The first image formation in the first image forming unit is:
(I) at least a first charging step for charging the first photoconductor having amorphous silicon or an amorphous silicon layer, a first exposure step, and a first developing step using a first developing sleeve;
(Ii) The first photoconductor has a diameter of 20 to 80 mm, and the first exposure is performed after the development area of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V in the first charging step. An electrostatic charge image is formed on the first photoconductor by exposure by the process,
(Iii) In the first developing step, a two-component developer containing the first toner and the first magnetic carrier forms a magnetic brush on the first developing sleeve;
(Iv) The first photosensitive member and the first developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The first developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the first photosensitive member, and the first electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a first toner image on the first photoreceptor,
(B) The second image formation in the second image forming unit is:
(I) at least a second charging step for charging the second photosensitive member having amorphous silicon or an amorphous silicon layer, a second exposure step, and a second developing step using a second developing sleeve;
(Ii) The second photoconductor has a diameter of 20 to 80 mm, and the second exposure is performed after the developing area of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V in the second charging step. An electrostatic charge image is formed on the second photoreceptor by exposure in the process,
(Iii) In the second developing step, a two-component developer containing the second toner and the second magnetic carrier forms a magnetic brush on the second developing sleeve;
(Iv) The second photosensitive member and the second developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The second developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the second photoconductor, while the second electrostatic charge image is generated by the magnetic brush of the two-component developer. Is developed to form a second toner image on the second photoreceptor,
(C) The third image formation in the third image forming unit is:
(I) at least a third charging step for charging a third photosensitive member having amorphous silicon or an amorphous silicon layer, a third exposure step, and a third developing step using a third developing sleeve;
(Ii) The third photosensitive member has a diameter of 20 to 80 mm, and the third exposure is performed after the developing region of the photosensitive member facing the developing sleeve is charged to an absolute value of 300 to 450 V in the third charging step. An electrostatic charge image is formed on the third photoconductor by exposure by the process,
(Iii) In the third developing step, a two-component developer containing a third toner and a third magnetic carrier forms a magnetic brush on the third developing sleeve,
(Iv) The third photosensitive member and the third developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The third developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the third photosensitive member, and the third electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a third toner image on the third photoconductor,
(D) The fourth image formation in the fourth image forming unit is:
(I) at least a fourth charging step for charging a fourth photoconductor having amorphous silicon or an amorphous silicon layer, a fourth exposure step, and a fourth developing step using a fourth developing sleeve;
(Ii) The fourth photosensitive member has a diameter of 20 to 80 mm, and after the developing region of the photosensitive member facing the developing sleeve is charged to an absolute value of 300 to 450 V in the fourth charging step, the fourth exposure is performed. An electrostatic charge image is formed on the fourth photoconductor by the process,
(Iii) In the fourth developing step, the fourth developing means has a one-component developer containing the fourth toner and a fourth developing sleeve for transporting the developer to the developing region. ,
(Iv) The fourth photoconductor and the fourth developing sleeve are installed such that the minimum gap is 100 to 500 μm.
(V) The fourth developing sleeve develops the fourth electrostatic charge image with a one-component developer while rotating at a peripheral speed 1.1 to 4.0 times the peripheral speed of the fourth photoconductor. Forming a fourth toner image on the fourth photoreceptor;
(E) The first toner, the second toner, the third toner, and the fourth toner have different color tones, and the nonmagnetic yellow toner, the nonmagnetic magenta toner, the nonmagnetic cyan toner, Selected from the group consisting of magnetic black toner,
(A) Non-magnetic yellow toner, non-magnetic magenta toner, non-magnetic cyan toner and magnetic black toner have positive chargeability, and the weight average particle diameter of each toner is 4.0 to 10.0 μm,
(B) The 50% volume average particle size of the magnetic carrier of the two-component developer is 10 to 80 μm,
(C) For the transfer force of each color, the image density after fixing once when the amount of unfixed toner (M / S) on the transfer material is M / S = 0.5 mg / cm ² is defined as D0.5. When the yellow toner coloring power is D0.5Y, the magenta toner coloring power is D0.5M, the cyan toner coloring power is D0.5C, and the black toner coloring power is D0.5Bk, D0.5Y, D0. 5M, D0.5C, and D0.5Bk are 1.0 to 1.8, respectively, and the coloring power of a toner that exhibits the maximum coloring power in three colors of yellow, magenta, and cyan is D0.5max, and the minimum coloring power. In the image forming method, the difference between D0.5max and D0.5min is 0 to 0.5, when the coloring power of the material having a colorant of D0.5min is shown.   The non-magnetic yellow toner is selected from the group consisting of CI Pigment Yellow 74, 93, 97, 109, 128, 151, 154, 155, 166, 168, 180 and 185. The image forming method according to claim 1, further comprising a yellow pigment.   The non-magnetic magenta toner may be a quinacridone pigment or CI Pigment Red (CI Pigment Red) 48: 2, 57: 1, 58: 2, or Shii Eye Pigment Red (C CI Pigment Red) 5, 31, 146, 147, 150, 184, 187, 238, 245, or CI Pigment Red 185, 265 3. The image forming method according to claim 1, further comprising a magenta pigment.   The image forming method according to claim 1, wherein the nonmagnetic cyan toner contains a Cu-phthalocyanine pigment or an Al-phthalocyanine pigment.   The image forming method according to claim 1, wherein the magnetic black toner contains magnetite.   6. The image forming method according to claim 1, wherein D0.5Y, D0.5M, D0.5C, and D0.5Bk are 1.1 to 1.7, respectively.   The image forming method according to claim 1, wherein the first to fourth photoconductors are positive or negatively charged amorphous silicon or a photoconductor having an amorphous silicon layer. .   The first to fourth photoconductors are photoconductors having positively charged amorphous silicon or an amorphous silicon layer, and latent images are formed by image exposure. The image forming method according to item.   The first to fourth photoconductors are photoconductors having negatively charged amorphous silicon or an amorphous silicon layer, and latent images are formed by back scan exposure. The image forming method according to one item.   The first to fourth toners contain at least one of a quaternary ammonium salt, an imidazole compound, an ammonio group-containing styrene acrylic copolymer resin, and a phosphonium compound positive charge control agent. The image forming method according to claim 1.   The image forming method according to claim 1, wherein the two-component developer has a 50% volume average particle diameter of 20 to 70 μm of a magnetic carrier.   The said 1st-4th toner consists of binder resin which has as a main component 1 type chosen from the group which consists of polyester, styrene acryl, and those modified substances. The image forming method according to item.   The image forming method according to claim 12, wherein the polyester has an acid value of 35 mgKOH / g or less.   The image forming method according to claim 1, wherein the toner has a glass transition temperature (Tg) of 50 to 70 ° C. The first toner image formed by the first image forming unit, the second toner image formed by the second image forming unit, the third toner image formed by the third image forming unit, and the fourth toner image The fourth toner image formed by the image forming unit is transferred to the transfer material with or without the intermediate transfer member, and the transfer material having the first, second, third, and fourth toner images is transferred. An image forming apparatus that transports to a heat and pressure fixing means, performs heat and pressure fixing, and forms a full-color image or a multi-color image on a transfer material,
(A) The first image forming unit is
(I) at least a first photosensitive member having amorphous silicon or an amorphous silicon layer, a first charging unit, a first exposure unit, and a first developing unit having a first developing sleeve;
(Ii) The first photoconductor has a diameter of 20 to 80 mm, and the first exposure is performed after the developing region of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V by the first charging unit. An electrostatic charge image is formed on the first photoreceptor by exposure by means,
(Iii) The first developing means has a two-component developer containing a first toner and a first magnetic carrier, and the two-component developer uses a magnetic brush on the first developing sleeve. Forming,
(Iv) The first photosensitive member and the first developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The first developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the first photosensitive member, and the first electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a first toner image on the first photoreceptor,
(B) The second image forming unit is
(I) at least a second photosensitive member having amorphous silicon or an amorphous silicon layer, a second charging unit, a second exposing unit, and a second developing unit having a second developing sleeve;
(Ii) The second photoconductor has a diameter of 20 to 80 mm, and the second exposure is performed after the development area of the photoconductor facing the developing sleeve is charged to 300 to 450 V in absolute value by the second charging unit. An electrostatic charge image is formed on the second photoreceptor by exposure by means,
(Iii) The second developing means has a two-component developer containing a second toner and a second magnetic carrier, and the two-component developer uses a magnetic brush on the second developing sleeve. Forming,
(Iv) The second photosensitive member and the second developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The second developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the second photoconductor, while the second electrostatic charge image is generated by the magnetic brush of the two-component developer. Is developed to form a second toner image on the second photoreceptor,
(C) The third image forming unit is
(I) at least a third photosensitive member having amorphous silicon or an amorphous silicon layer, a third charging unit, a third exposing unit, and a third developing unit having a third developing sleeve;
(Ii) The third photoconductor has a diameter of 20 to 80 mm, and the third exposure is performed after the developing region of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V by the third charging unit. An electrostatic charge image is formed on the third photoreceptor by exposure by means,
(Iii) The third developing means has a two-component developer containing a third toner and a third magnetic carrier, and the two-component developer uses a magnetic brush on the third developing sleeve. Forming,
(Iv) The third photosensitive member and the third developing sleeve are installed so that the minimum gap is 350 to 800 μm.
(V) The third developing sleeve rotates at a peripheral speed 1.1 to 4.0 times the peripheral speed of the third photosensitive member, and the third electrostatic charge image is generated by the magnetic brush of the two-component developer. To form a third toner image on the third photoconductor,
(D) The fourth image forming unit
(I) at least a fourth photosensitive member having amorphous silicon or an amorphous silicon layer, a fourth charging unit, a fourth exposing unit, and a fourth developing unit having a fourth developing sleeve;
(Ii) The fourth photoconductor has a diameter of 20 to 80 mm, and after the development area of the photoconductor facing the developing sleeve is charged to an absolute value of 300 to 450 V by the fourth charging unit, An electrostatic charge image is formed on the fourth photoconductor by the exposure means,
(Iii) In the fourth developing step, the fourth developing means has a one-component developer containing the fourth toner and a fourth developing sleeve for transporting the developer to the developing region. ,
(Iv) The fourth photoconductor and the fourth developing sleeve are installed such that the minimum gap is 100 to 500 μm.
(V) The fourth developing sleeve develops the fourth electrostatic charge image with a one-component developer while rotating at a peripheral speed 1.1 to 4.0 times the peripheral speed of the fourth photoconductor. Forming a fourth toner image on the fourth photoreceptor;
(E) The first toner, the second toner, the third toner, and the fourth toner have different color tones, and the nonmagnetic yellow toner, the nonmagnetic magenta toner, the nonmagnetic cyan toner, Selected from the group consisting of magnetic black toner,
(A) Non-magnetic yellow toner, non-magnetic magenta toner, non-magnetic cyan toner and magnetic black toner have positive chargeability, and the weight average particle diameter of each toner is 4.0 to 10.0 μm,
(B) The 50% volume average particle size of the magnetic carrier of the two-component developer is 10 to 80 μm,
(C) For the transfer force of each color, the image density after fixing once when the amount of unfixed toner (M / S) on the transfer material is M / S = 0.5 mg / cm ² is defined as D0.5. When the yellow toner coloring power is D0.5Y, the magenta toner coloring power is D0.5M, the cyan toner coloring power is D0.5C, and the black toner coloring power is D0.5Bk, D0.5Y, D0. 5M, D0.5C, and D0.5Bk are 1.0 to 1.8, respectively, and the coloring power of a toner that exhibits the maximum coloring power in three colors of yellow, magenta, and cyan is D0.5max, and the minimum coloring power. The image forming apparatus is characterized in that the difference between D0.5max and D0.5min is 0 to 0.5 when the coloring power of the display is D0.5min.   The non-magnetic yellow toner is selected from the group consisting of CI Pigment Yellow 74, 93, 97, 109, 128, 151, 154, 155, 166, 168, 180 and 185. 16. The image forming apparatus according to claim 15, further comprising a yellow pigment.   The non-magnetic magenta toner may be a quinacridone pigment or CI Pigment Red (CI Pigment Red) 48: 2, 57: 1, 58: 2, or Shii Eye Pigment Red (C CI Pigment Red) 5, 31, 146, 147, 150, 184, 187, 238, 245, or CI Pigment Red 185, 265 17. The image forming apparatus according to claim 15, further comprising a magenta pigment.   The image forming apparatus according to claim 15, wherein the nonmagnetic cyan toner contains a Cu-phthalocyanine pigment or an Al-phthalocyanine pigment.   The image forming apparatus according to claim 15, wherein the magnetic black toner contains magnetite.   The image forming apparatus according to any one of claims 15 to 19, wherein the D0.5Y, D0.5M, D0.5C, and D0.5Bk are 1.1 to 1.7, respectively.   21. The image forming apparatus according to claim 15, wherein the first to fourth photoconductors are positive or negatively charged amorphous silicon or a photoconductor having an amorphous silicon layer. .   The first to fourth photoconductors are photoconductors having positively charged amorphous silicon or an amorphous silicon layer, and latent images are formed by image exposure. The image forming apparatus according to Item.   The first to fourth photoconductors are photoconductors having negatively charged amorphous silicon or an amorphous silicon layer, and latent images are formed by back scan exposure. The image forming apparatus according to one item.   16. The first to fourth toners contain at least one of a quaternary ammonium salt, an imidazole compound, an ammonio group-containing styrene acrylic copolymer resin, and a phosphonium compound positive charge control agent. 24. The image forming apparatus according to any one of items 1 to 23.   25. The image forming apparatus according to claim 15, wherein the two-component developer has a 50% volume average particle diameter of a magnetic carrier of 20 to 70 [mu] m.   The said 1st-4th toner consists of binder resin which has as a main component 1 type chosen from the group which consists of polyester, styrene acryl, and those modified substances, Any one of Claims 15-25 characterized by the above-mentioned. The image forming apparatus described in the item.   27. The image forming apparatus according to claim 26, wherein the polyester has an acid value of 35 mgKOH / g or less.   The image forming apparatus according to claim 15, wherein the toner has a glass transition temperature (Tg) of 50 to 70 ° C.

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