JP2006293335A - Image forming apparatus, toner for image formation, and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which ensures high transfer efficiency, does not cause image defects due to faulty cleaning, and gives high image quality, a toner for image formation used in the image forming apparatus and a process cartridge. <P>SOLUTION: Powder prepared by mixing a spherical toner and an amorphous toner is used as the above toner, wherein the ratio (F1/Q1)/(F2/Q2) of the value F1/Q1 given by dividing an average adherence F1 between an image carrier and the amorphous toner by an average charge amount Q1 per particle of the amorphous toner to the value F2/Q2 given by dividing an average adherence F2 between the image carrier and the spherical toner by an average charge amount Q2 per particle of the spherical toner is ≤0.8, and a mixing ratio of the amorphous toner in the mixed powder is 5-25%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile using a dry two-component or one-component developer. The present invention also relates to an image forming toner and a process cartridge used in the image forming apparatus.

  Conventionally, various methods are known for electrophotography, and generally the surface of an image carrier is charged, and the charged image carrier is exposed to form an electrostatic latent image. Next, toner is developed on the electrostatic latent image to form a toner image on the image carrier. Further, the toner image on the image carrier is directly transferred onto the recording material through the intermediate transfer member, and the transferred toner image is fixed by heating, pressure, or a combination thereof, thereby recording the recording material. A recorded matter having an image formed thereon is obtained. The toner remaining on the image carrier after the toner image transfer is cleaned by a known method such as a blade, a brush, or a roller.

  Recent trends in electrophotographic technology require colorization, high speed, high image quality, and digitalization. As a color image forming method, there is a method in which a toner image of each color is formed on a single image carrier by a plurality of developing devices, each color image is transferred onto an intermediate transfer member, and transferred from the intermediate transfer member onto a recording material. is there. In addition, a plurality of image carriers, developing devices, and transfer devices are arranged side by side, toner images of each color are formed on each image carrier, and sequentially transferred to a recording material, or sequentially transferred to an intermediate transfer material and then transferred to a recording material. There is a so-called tandem method of transferring. The former method has the advantage that the entire apparatus can be made relatively small and the cost is low, but has the disadvantage that it is difficult to increase the image forming speed. The tandem method has the disadvantage that the apparatus tends to be large and the cost is high, but has the advantage that the image forming speed can be increased. Has been.

  For improving the image quality, for example, a high-resolution image having a resolution of 1200 dpi or higher has been studied. In order to realize this, a higher-definition image forming method than before is desired. Also for toner and developer for visualizing a latent image, further reduction in particle size is being studied and realized in order to form a high-definition image. Further, in order to cope with the digitization of images, the reproducibility of dots for forming images is required, and the uniformity of toner for forming dots is required. For this reason, a toner obtained by subjecting a pulverized toner to spherical processing by a hot air flow or fluidized granulation method, or a suspension, rather than a non-uniformly pulverized toner produced by a mechanical pulverization method that has been mainly used conventionally. A spherical toner such as a polymerized toner obtained by a polymerization method, an emulsion polymerization method, a dispersion polymerization method or the like is more advantageous.

  A cleaning device using a cleaning blade that removes toner by pressing a blade made of an elastic member against an image carrier is simple in construction, easy to downsize, and advantageous in terms of cost. However, when spherical toner is used, there is a problem that the toner easily slips through the blade and an image defect due to poor cleaning is likely to occur.

  As a countermeasure, it has been proposed to use various neutralizing means for the spherical toner remaining on the photoconductor after the transfer step to reduce the charge amount of the residual toner and improve the cleaning property (for example, Patent Documents). 1 and 2). However, newly providing the static eliminating means directly leads to an increase in the number of parts and an increase in manufacturing cost.

  In addition, it has been proposed to suppress slipping of spherical toner by increasing the contact pressure of the cleaning blade against the photosensitive member (see, for example, Patent Document 3). However, as the contact pressure is increased, the cleaning blade is more likely to be chipped or the photoconductor is damaged, resulting in poor cleaning.

  In addition, it has been proposed to use a toner in which a spherical toner and an irregular toner are mixed (see, for example, Patent Documents 4, 5, and 6). However, this method is disadvantageous to the environment because the high transferability of the spherical toner is impaired, the amount of residual toner on the photoreceptor increases, and the amount of toner collected by cleaning increases. . In addition, when the toner collected by cleaning is reused by providing a recycling mechanism, or the transfer residual toner is collected in the process of charging the image carrier without developing the cleaning means or developing the toner on the image carrier. Even in the cleanerless type image forming apparatus, the characteristics of the toner collected due to various stresses are often changed with respect to the normal toner, so that an image defect due to the collected toner tends to occur.

In addition, a method using a spherical toner as a color toner and an irregular toner as a black toner has been proposed (see, for example, Patent Documents 7 and 8). However, this method cannot be applied to a tandem-type full-color image forming apparatus in which different photoconductors correspond to toners of respective colors.
JP-A-9-96965 JP-A-9-114232 Japanese Patent Laid-Open No. 10-214013 Japanese Patent Publication No. 3-22979 Japanese Patent Laid-Open No. 6-148941 JP 7-49584 A JP-A-8-254873 JP 9-258474 A

  Accordingly, the present invention has been made in view of the above-described problems, and the object of the present invention is to form a high-quality image that has high transfer efficiency and does not cause image defects due to poor cleaning or the like. Is to provide a device.

According to the first aspect of the present invention, at least the means for forming an electrostatic latent image on the image carrier, the developing means for forming a toner image on the image carrier, and the toner image formed on the image carrier are intermediate. In an image forming apparatus having a step of transferring onto a transfer member or a recording material, and a step of removing toner remaining on the image carrier using a cleaning blade,
As the toner, powder mixed with spherical toner and irregular toner is used,
A value F1 / Q1 obtained by dividing the average value F1 of the adhesion force between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, and the interposition between the image carrier and the spherical toner. The ratio F2 / Q2 (F1 / Q1) / (F2 / Q2) obtained by dividing the average value F2 of the adhesion force by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. Achieved by the image forming apparatus.

  According to the first aspect of the present invention, the transfer efficiency is increased by mixing the irregular toner with the spherical toner and controlling the ratio between the adhesion between the image carrier and the toner and the charge amount per one toner particle. In addition, it is possible to provide a high-quality image forming apparatus that does not cause image defects due to defective cleaning or the like.

According to a second aspect of the present invention, at least means for forming an electrostatic latent image on the image carrier, a plurality of developing means for forming toner images of different colors on the image carrier, and formation on the image carrier. In a color image forming apparatus having a step of transferring the toner image to a recording medium and a step of removing the toner remaining on the image carrier using a cleaning blade,
As each toner, powder mixed with spherical toner and irregular toner is used,
For each toner, a value F1 / Q1 obtained by dividing the average value F1 of the adhesion between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, the image carrier and the toner A ratio (F1 / Q1) / (F2 / Q2) of F2 / Q2 obtained by dividing the average value F2 of the adhesion force between the spherical toners by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. This is achieved by the image forming apparatus.

  According to the second aspect of the invention, for each color toner, the spherical toner is mixed with the irregular toner, and the ratio between the adhesion between the image carrier and the toner and the charge amount per toner particle is controlled. In addition, it is possible to provide a high-quality color image forming apparatus that has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

According to a third aspect of the present invention, at least means for forming an electrostatic latent image on an image carrier, development means for forming a toner image on the image carrier, and a toner image formed on the image carrier are provided. A plurality of image forming elements having a step of transferring to a recording medium and a step of removing toner remaining on the image carrier using a cleaning blade, and using a plurality of color toners for each image forming element, In an image forming apparatus for forming a color image,
As the toner used for each image element, powder mixed with spherical toner and irregular toner is used,
In each of the image elements, a value F1 / Q1 obtained by dividing the average value F1 of the adhesion between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, the image carrier, A ratio (F1 / Q1) / (F2 / Q2) of F2 / Q2 obtained by dividing the average value F2 of the adhesion between the spherical toners by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. This is achieved by an image forming apparatus.

  According to the third aspect of the invention, for each image element, spherical toner is mixed with amorphous toner, and the ratio between the adhesion between the image carrier and the toner and the charge amount per one toner particle is controlled. In addition, it is possible to provide a high-quality color image forming apparatus that has a high image forming speed, high transfer efficiency, and no image defects due to poor cleaning or the like.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the transfer means includes an intermediate transfer member on which a toner image formed on the image carrier is primarily transferred, and the intermediate transfer member supported on the intermediate transfer member. Transfer means for secondary transfer of the toner image to a recording medium.

  According to the invention described in claim 4, by using the intermediate transfer member, it is possible to provide a color image forming apparatus which can cope with various types of paper and can be easily reduced in size.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the mixing ratio of the irregular shaped toner in the mixed powder is 5 to 25%.

  According to the invention described in claim 5, by setting the mixing ratio of the irregular shaped toner in the mixed powder within a certain range, the transfer efficiency is high, and the high-quality image that does not cause the image defect due to the cleaning defect or the like. A forming apparatus can be provided.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, characterized in that the external additive coverage of the irregular toner is larger than the external additive coverage of the spherical toner. .

  According to the sixth aspect of the present invention, the adhesion between the image carrier and the toner can be controlled by controlling the external additive coverage of the irregular toner and the spherical toner, the transfer efficiency is high, and the cleaning is poor. It is possible to provide a high-quality image forming apparatus that does not cause image defects due to the above.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein an average value of the shape factor SF1 of the irregular toner is 130 or more.

  According to the seventh aspect of the invention, the effect of suppressing the cleaning failure can be obtained by defining SF1 of the irregular toner mixed with the spherical toner.

  The invention according to an eighth aspect is the invention according to any one of the first to seventh aspects, wherein an average value of the shape factor SF1 of the spherical toner is 100 to 130.

  According to the eighth aspect of the invention, the effect of improving the transfer efficiency can be obtained by defining SF1 of the spherical toner.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the ratio D1 / D2 of the volume average particle diameter D1 of the irregular toner and the volume average particle diameter D2 of the spherical toner is 0. .8 to 1.2.

  According to the ninth aspect of the present invention, by making the particle sizes of the irregular toner and the spherical toner substantially the same, the difference between the development characteristics and the transfer characteristics of the two toners can be suppressed, and the deterioration of the image quality can be suppressed.

  A tenth aspect of the invention is characterized in that, in the invention according to any one of the first to ninth aspects, the volume-average particle size of the irregular toner and the spherical toner is 3 to 9 μm.

  According to the tenth aspect of the present invention, it is possible to suppress a decrease in image quality by setting the particle diameter of the toner within a certain range.

  According to an eleventh aspect of the present invention, in the invention according to any one of the first to tenth aspects, an average value of primary particle diameters of the external additives covering the amorphous toner and the spherical toner is 10 nm to 200 nm. It is characterized by that.

  According to the eleventh aspect of the present invention, the durability of the developer can be ensured and the photoreceptor or the like can be prevented from being damaged by setting the particle size of the external additive within a certain range.

  The invention according to claim 12 can be achieved by an image forming toner used in the image forming apparatus according to any one of claims 1 to 11.

  According to the twelfth aspect of the present invention, it is possible to provide a high-quality image forming toner that has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

  According to a thirteenth aspect of the present invention, there is provided a process in which at least one unit selected from a photosensitive member, a charging unit, a developing unit storing a developer, and a cleaning unit is integrally supported and detachably attached to the image forming apparatus main body. The toner used in the developer, which is a cartridge, can be achieved by a process cartridge characterized by being a toner according to claim 12.

  According to the thirteenth aspect of the present invention, it is possible to provide a high-quality process cartridge that has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

  According to the present invention, irregular toner is mixed with spherical toner, and the ratio between the adhesion between the image carrier and the toner and the charge amount per one toner particle is controlled, so that the transfer efficiency is high and the cleaning failure, etc. Therefore, it is possible to provide a high-quality image forming apparatus that does not cause image defects.

  Further, in the present invention, by defining SF1 of irregular toner and spherical toner, it is possible to obtain an effect of suppressing poor cleaning and improving transfer efficiency.

  The present invention also makes it possible to suppress the difference between the development characteristics and transfer characteristics of both toners by making the particle sizes of the irregular toner and the spherical toner comparable, and to suppress a decrease in image quality. By making it within this range, it is possible to suppress degradation of image quality, and by making the particle size of the external additive within a certain range, it is possible to ensure the durability of the developer and prevent damage to the photoconductor, etc. .

  Furthermore, the present invention can provide a high-quality image forming toner that is used in the image forming apparatus of the present invention and has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

  Furthermore, the toner used for the developer is a high-quality toner that has high transfer efficiency and does not cause image defects due to poor cleaning, etc., the photosensitive member, the charging means, the developing means containing the developer, and the cleaning. It is possible to provide a process cartridge which integrally supports at least one means selected from the means and is detachable from the main body of the image forming apparatus.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

  The image forming apparatus of the present invention will be described in detail with reference to the drawings.

  The image forming apparatus of the present invention is formed on a latent image forming unit for forming an electrostatic latent image on the image carrier, a developing unit for forming a toner image on the latent image on the image carrier, and the image carrier. Transfer means for transferring the toner image onto the intermediate transfer member or recording material, fixing means for fixing the toner image on the recording material, cleaning means for removing and collecting the toner remaining on the image carrier without being transferred Have

  FIG. 3 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention. In FIG. 3, a charging device 22 for charging the drum surface, an exposure device 23 for forming a latent image on a uniformly charged surface, around a photosensitive drum 21 serving as an electrostatic latent image carrier. A developing device 24 that forms a toner image by attaching charged toner to the latent image on the surface of the drum, a transfer device 25 that transfers the toner image on the formed drum onto the recording material 26, and a toner on the recording material is fixed. A fixing device 27, a cleaning device 30 for removing and collecting the residual toner on the drum, and a static eliminating device 31 for removing the residual potential on the drum are arranged in this order.

  First, the surface of the photosensitive drum 21 is uniformly charged by the charging roller 22. In the example of FIG. 3, the photosensitive drum 21 is charged using a charging roller, but there is no particular limitation and can be appropriately selected according to the purpose. For example, a conductive or semiconductive roller or brush And a known contact charger equipped with a film, a rubber blade, etc., and a non-contact charger using corona discharge such as corotron and scorotron.

  The shape of the charging member may take any form such as a magnetic brush or a fur brush in addition to the roller, and can be selected according to the specifications and form of the electrophotographic apparatus. When using a magnetic brush, the magnetic brush is composed of, for example, various ferrite particles such as Zn-Cu ferrite as a charging member, and a non-magnetic conductive sleeve for supporting it, and a magnet roll included in the non-magnetic conductive sleeve. Is done. When using a brush, for example, as the material of the fur brush, for example, a fur treated with carbon, copper sulfide, metal or metal oxide is used, and this is wound around a metal or other conductive core. The charging device is made by pasting.

  Although the charging device is not limited to the contact type charging device as described above, it is preferable to use a contact type charging device because an image forming apparatus with reduced ozone generated from the charging device can be obtained. .

  Next, the charged photosensitive drum 21 is irradiated with a laser beam 23 in accordance with the image information to form an electrostatic latent image. In the example of FIG. 3, a laser is used, but there is no particular limitation, and it can be appropriately selected according to the purpose. Various exposures such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. Apparatus. In addition, the charging potential and the exposure part on the photosensitive drum 21 can be detected by a potential sensor to control the charging condition and the exposure condition.

  Next, the developing device 24 forms a toner image on the photosensitive drum 21 on which the electrostatic latent image is formed. FIG. 4 shows a configuration example in the case where the image device 24 is a two-component developing device using a two-component developer composed of toner and carrier. In this example, the developer is stirred and conveyed by the screw 41 and supplied to the developing sleeve 42. The developer supplied to the developing sleeve 42 is regulated by a doctor blade 43, and the amount of developer supplied is controlled by a doctor gap that is a distance between the doctor blade 43 and the developing sleeve 42. If the doctor gap is too small, the developer amount is too small and the image density becomes insufficient. Conversely, if the doctor gap is too large, the developer amount is excessively supplied and carrier adhesion occurs on the photosensitive drum 21. Problems arise. The developing sleeve 42 is provided with a magnet that forms a magnetic field so that the developer is sprinkled on the peripheral surface, and the developer is placed on the developing sleeve 42 so as to follow a normal magnetic field line emitted from the magnet. A magnetic brush is formed with a chain. The developing sleeve 42 and the photosensitive drum 21 are disposed so as to be close to each other with a certain gap (developing gap) therebetween, and a developing region is formed in a portion facing both. The developing sleeve 42 is formed of a non-magnetic material such as aluminum, brass, stainless steel, or conductive resin in a cylindrical shape, and is rotated by a rotation driving mechanism (not shown). The magnetic brush is transferred to the developing area by the rotation of the developing sleeve 42. A developing voltage is applied to the developing sleeve 42 from a developing power source (not shown), and the toner on the magnetic brush is separated from the carrier by the developing electric field formed between the developing sleeve 42 and the photosensitive drum 21, and then on the photosensitive drum 21. Is developed on the electrostatic latent image. An alternating current may be superimposed on the development voltage. The development gap can be set to 0.5 mm to 1.5 mm when the developer particle diameter is about 5 to 30 times and the developer particle diameter is 50 μm. If it is wider than this, it is difficult to obtain a desirable image density. Further, the doctor gap needs to be the same as or slightly larger than the development gap. The drum diameter and drum linear speed of the photosensitive drum 21 and the sleeve diameter and sleeve linear speed of the developing sleeve 42 are determined by restrictions such as the copying speed and the size of the apparatus. The ratio of the sleeve linear velocity to the drum linear velocity needs to be 1.1 or more in order to obtain a necessary image density. It is also possible to control the process conditions by installing a sensor at a position after development and detecting the toner adhesion amount from the optical reflectance.

For the carrier constituting the magnetic brush, magnetic powder such as iron powder, ferrite powder, resin particles in which magnetic particles are dispersed, and magnetic powder whose surface is coated with a resin or the like for controlling electric characteristics are preferable. used. As the carrier constituting the magnetic brush, spherical particles are preferably used in order to reduce damage to the surface of the photosensitive drum 21, and those having an average particle diameter of 150 μm or less are preferable. If the average particle diameter of the carrier is too large, the radius of curvature is large even if the average particle diameter is arranged in the close-packed state, the area not in contact with the photosensitive drum 21 is increased, and the toner image is dropped or missing. On the other hand, if the average particle size is too small, when an AC voltage is applied, the particles easily move and exceed the magnetic force between the particles, and the particles are scattered and cause carrier adhesion. The average particle diameter of the carrier is particularly preferably 30 μm or more and 100 μm or less. Furthermore, if the volume resistivity of the carrier is too low, charges are injected into the carrier when a developing voltage is applied, causing carrier adhesion to the photosensitive drum 21 or dielectric breakdown of the photosensitive member. However, it is necessary to use a carrier of 10 ³ Ωcm or more.

  In the example of FIG. 4, a two-component developing device is used as the developing device. However, the present invention is not limited to the two-component developing device, and the toner thin layer formed on the developing sleeve is developed on the photosensitive member with an electric field. A one-component developing device may be used.

  The toner image formed on the photosensitive drum 21 is conveyed to a transfer nip where the photosensitive drum 21 and the recording material 26 are in contact with each other. A transfer voltage having a polarity opposite to that of toner is applied to a roller 25 that contacts a recording material 26 conveyed from a paper supply tray (not shown) by a transfer power supply (not shown), and acts between the recording material 26 and the photosensitive drum 21. The toner image formed on the photosensitive drum 21 is transferred onto the recording material 26 by the transfer electric field. In the example of FIG. 3, transfer is performed by applying a voltage to the roller, but there is no particular limitation, and it can be appropriately selected according to the purpose, and a corona discharge device or the like can be used.

  The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

  The recording material 26 on which the unfixed toner image is placed is applied with a certain amount of heat and pressure by the fixing roller 28 and the pressure roller 29, and the toner image is fixed on the recording material 26. In order to keep the fixing temperature constant, a thermistor (not shown) is in contact with the fixing roller 28 to control the temperature of the fixing roller 28. A fixing method using a fixing roller has high thermal efficiency, excellent safety, can be miniaturized, and has a wide range of applications from low speed to high speed.

  The toner remaining on the photosensitive drum 21 is removed by the cleaning device 30, but a cleaning blade may be used as the cleaning device, and a cleaning roller, a cleaning brush, or the like may be used in combination. Further, the cleaning efficiency can be increased by applying a voltage having a polarity opposite to that of the toner to these cleaning members. The toner cleaned from the photosensitive drum 21 is discarded or recycled in the apparatus.

  The residual potential of the photosensitive drum 21 is removed by the static eliminator 31 after cleaning. The neutralizing means is not particularly limited as long as it can apply a neutralizing bias to the photoconductor, and can be appropriately selected from known neutralizers. For example, a neutralizing lamp is preferable.

  FIG. 5 is a schematic configuration diagram showing an example of a color image forming apparatus of the present invention. In the apparatus 51, a charging device 51b, an exposure device 51c, a developing device 51d, a transfer device 51e, a cleaning device 51f, and a charge eliminating device 51g are disposed around the photosensitive drum 51a, and are formed on the photosensitive drum 51a. The yellow toner image is transferred onto the intermediate transfer belt 55 by the transfer device 51e, and the toner remaining on the photosensitive drum 51a is removed by the cleaning device 51f. Similarly, an image of magenta toner, cyan toner, and black toner is formed on the intermediate transfer belt 55 by the devices 52 to 54. The color image on the intermediate transfer belt 55 is transferred onto the recording material 57 by the transfer device 56, and the toner remaining on the intermediate transfer belt 55 is removed by the cleaning device 58. The color image formed on the recording material 57 is fixed by a fixing device (not shown). The order in which the color images are formed is not specified and may be formed in any order.

  FIG. 6 is a schematic configuration diagram showing another example of the color image forming apparatus of the present invention. Around the photosensitive drum 61, a charging device 62, an exposure device 63, a developing device 64, a transfer device 65, a cleaning device 73, and a charge eliminating device 74 are disposed. The developing device 64 includes four developing devices 64Y, 64M, 64C, and 64B using yellow, magenta, cyan, and black toners, and selects a developing device that forms a toner image on the photosensitive drum 61 by a rotating operation. It is configured as follows. An electrostatic latent image corresponding to yellow is formed on the photosensitive drum 61, a yellow toner image is formed by the developing device 64Y, the yellow toner image is transferred onto the transfer belt 67, and the transfer residual on the photosensitive drum 61 is transferred. The toner is removed by the cleaning device 73, and the residual potential on the drum is removed by the charge removal device 73. Next, an electrostatic latent image corresponding to magenta is formed on the photosensitive drum 61, a magenta toner image is formed by the developing device 64M, and the magenta toner image is formed on the intermediate transfer belt 67 on which the yellow toner image is formed. Is transcribed. Similarly, images of cyan toner and black toner are transferred onto the intermediate transfer belt 67, and transferred onto the recording material 69 at once by a transfer voltage applied to the roller 66e. The intermediate transfer belt 67 can contact and separate from the photosensitive drum 61 and is isolated from the photosensitive drum 61 when the toner image is not transferred. The color image formed on the recording material 69 is fixed by the fixing device 70.

  The present invention is characterized in that, in the example of the image forming apparatus as described above, the toner transfer efficiency is high, the cleaning defect does not occur, and good image quality is obtained.

  In the image forming apparatus as shown in FIG. 3, when a spherical toner is used, a high transfer rate can be obtained. However, the untransferred spherical toner remaining on the photosensitive drum easily slips through the cleaning blade and easily causes poor cleaning. On the other hand, when an irregular toner is used, poor cleaning hardly occurs, but the transfer rate is lower than when a spherical toner is used.

  As a result of examining the case where spherical toner and irregular toner are mixed, even when the mixing ratio of irregular toner is lower than that of spherical toner, the ratio of irregular toner to the residual toner becomes higher. It was found that the poor cleaning can be improved by mixing a small amount of irregularly shaped toner. However, the transfer rate is lower than when only spherical toner is used, and the amount of toner recovered by cleaning increases. If the mixing ratio of the irregular shaped toner is decreased, the transfer rate is increased, but the adhesion distribution of the irregular shaped toner remaining on the photosensitive drum becomes non-uniform, and partial cleaning failure tends to occur. In order to uniformly deposit a small amount of irregular shaped toner on the photosensitive drum after the transfer, it is necessary to increase the transfer rate of the irregular shaped toner without reducing the mixing ratio of the irregular shaped toner.

  The toner in contact with the photosensitive drum is subjected to the adhesion force f between the toner and the photosensitive drum, and the Coulomb force qE (q is the charge amount of one toner particle) due to the transfer electric field E. In addition, the toner in contact with the photosensitive drum is subjected to adhesion force and electrostatic repulsion force with peripheral toner, but these forces are small compared to the adhesion force f and the Coulomb force qE. For this reason, in order to transfer the toner in contact with the photosensitive drum, it is necessary to make the Coulomb force qE larger than the adhesion force f as shown in equation (1).

(１)式を変形すると(２)式のようになる。

When formula (1) is modified, formula (2) is obtained.

したがって、トナーと感光体ドラムの付着力ｆとトナー１粒子の帯電量ｑの比ｆ／ｑの小さいトナー粒子は、低い転写電界Ｅで転写できる。ｆ／ｑの大きいトナー粒子でも転写電界Ｅを大きくすれば転写できるが、転写電界を大きくすると感光体ドラムと記録材または転写ベルト間で放電が生じやすくなる。放電が生じると、感光体ドラムと記録材または転写ベルト間の実質的な電界が低下してしまうために転写率は良くならない。トナーは粒径や形状等に分布を有しており、また感光体も凹凸等により表面が不均一なため、付着力ｆや帯電量ｑには分布があり、ｆ／ｑにも分布がある。ｆ／ｑの平均値が小さいと、放電が生じる転写電界以下で転写可能なトナー粒子数の割合が高くなるため、高転写率を実現することができる。

Therefore, toner particles having a small ratio f / q of the adhesion force f between the toner and the photosensitive drum and the charge amount q of one toner particle can be transferred with a low transfer electric field E. Even toner particles having a large f / q can be transferred by increasing the transfer electric field E. However, if the transfer electric field is increased, electric discharge tends to occur between the photosensitive drum and the recording material or the transfer belt. When the discharge occurs, the substantial electric field between the photosensitive drum and the recording material or the transfer belt is lowered, so that the transfer rate is not improved. The toner has a distribution in particle size, shape, etc., and the surface of the photoreceptor is uneven due to unevenness, etc., so there is a distribution in adhesion force f and charge amount q, and there is also a distribution in f / q. . When the average value of f / q is small, the ratio of the number of toner particles that can be transferred below the transfer electric field at which discharge occurs is high, so that a high transfer rate can be realized.

  For various spherical toners and irregular toners, the inventors measured the average value F of the adhesion force between the toner and the photoreceptor by a centrifugal separation method and the average value Q of the charge amount of one toner particle by a blow-off method or the like. Obtained from the charged amount per unit weight, toners with various mixing ratios were prepared using these spherical toners and irregular toners, and the transfer rate and cleaning properties were evaluated. As a result, it has been found that by using the following irregular shaped toner and spherical toner and the mixing ratio as shown below, the transfer rate is high and no poor cleaning occurs, and good image quality can be obtained. It was.

(F1 / Q1) / (F2 / Q2) <0.8
F1 and Q1: F and Q of the irregular shaped toner,
F2 and Q2: F and Q of spherical toner
Amorphous toner mixing ratio = 5 to 25%
In addition, as shown in FIGS. 5 and 6, even when a color image is formed using a plurality of color toners, the above-mentioned irregular toner and spherical toner are used for each color toner, and the above-described mixing ratio is used. As a result, it has been found that the transfer rate is high, and no defective cleaning occurs, and a good color image quality can be obtained.

  A method of measuring the average value Q of the charge amount of one toner particle carried out by the present inventors will be described. A blow-off method used as a method for measuring the charge amount per unit weight of toner for a two-component developer composed of toner and carrier will be described. In the blow-off method, the developer is held in a Faraday cage having a mesh filter larger than the toner particle size and smaller than the carrier particle size, and the developer is sprayed with compressed air or the like to separate the toner from the carrier. The charge amount of the remaining carrier and the weight of the separated toner are measured, and the charge amount per unit weight is measured. As another method for measuring the charge amount of the toner, there is a sack-in method for sucking the toner adhering to the photosensitive drum and measuring the charge amount and the toner weight. The average value Q of the charge amount of one toner particle was determined by the product of the charge amount per unit weight and the average weight of one toner particle. The average weight M of one toner particle is obtained from the formula (3) using the true specific gravity ρ of the toner and the toner volume average particle diameter D.

次に、本発明者らが実施した遠心分離法によるトナーと感光体間の付着力測定方法について説明する。トナーの付着力を測定する方法は、トナーの付着している物体からトナーを分離するのに必要な力を見積もる方法が一般的である。トナーを分離させる方法としては、遠心力、振動、衝撃、空気圧、電界、磁界等を用いた方法が知られている。この内、遠心力を利用した方法は定量化が容易で、かつ測定精度が高い。このため、本発明ではトナーと感光体間の付着力を測定する方法として、遠心分離法を用いた。以下、遠心分離によるトナー付着力測定方法について説明するが、ＩＳ＆Ｔ ＮＩＰ７ｔｈ ｐ．２００(１９９１)などに記載されている方法が知られている。

Next, a method for measuring the adhesion force between the toner and the photoreceptor by the centrifugal separation method performed by the present inventors will be described. As a method for measuring the adhesion force of toner, a method for estimating a force necessary for separating toner from an object to which toner adheres is generally used. As a method for separating the toner, a method using centrifugal force, vibration, impact, air pressure, electric field, magnetic field or the like is known. Among these, the method using centrifugal force is easy to quantify and has high measurement accuracy. Therefore, in the present invention, the centrifugal separation method is used as a method for measuring the adhesion force between the toner and the photoreceptor. Hereinafter, a method for measuring toner adhesion by centrifugation will be described. IS & T NIP7th p. 200 (1991) and the like are known.

  1 and 2 are diagrams showing an example of a measurement cell and a centrifugal separator of a toner adhesion measuring device according to the present invention. FIG. 1 is an explanatory diagram of a measurement cell of the toner adhesion measuring apparatus. In FIG. 1, reference numeral 1 denotes a measurement cell. The measurement cell 1 includes a sample substrate 2 having a sample surface 2a to which toner is adhered, and a receiving substrate 3 having an adhesion surface 3a to which toner separated from the sample substrate 2 is adhered. The spacer 4 is provided between the sample surface 2 a of the sample substrate 2 and the attachment surface 3 a of the receiving substrate 3. FIG. 2 is a partial cross-sectional view of the centrifugal separator. In FIG. 2, reference numeral 5 denotes a centrifugal separator, and the centrifugal separator 5 includes a rotor 6 that rotates the measurement cell 1 and a holding member 7. The rotor 6 has a hole-shaped cross section perpendicular to the rotation center axis 9 of the rotor 6 and has a sample setting portion 8 where the holding member 7 is set. The holding member 7 includes a rod-like portion 7a, a cell holding portion 7b provided on the rod-like portion 7a for holding the measurement cell 1, a hole portion 7c for pushing the measurement cell 1 out of the cell holding portion 7b, and the rod-like portion 7a as a sample installation portion. 8 is provided with an installation fixing portion 7d to be fixed to 8. The cell holding unit 7b is configured such that when the measurement cell 1 is installed, the vertical direction of the measurement cell 1 is perpendicular to the rotation center axis 9 of the rotor.

  A method for measuring the adhesion force between the toner and the photoreceptor using the above apparatus will be described. First, a photoconductor is directly formed on the sample substrate 2 or a part of the photoconductor is cut out and attached to the sample substrate 2 with an adhesive. Next, toner is deposited on the photoreceptor (sample surface 2 a) on the sample substrate 2. Next, as shown in FIG. 1, the measurement cell 1 is configured using the sample substrate 2, the receiving substrate 3, and the spacer 4. The cell holding of the holding member 7 is performed so that the sample substrate 2 is positioned between the receiving substrate 3 and the rotation center axis 9 of the rotor 6 when the holding cell 7 is placed on the sample setting portion 8 of the rotor 6. Installed in part 7b. The holding member 7 is installed on the sample installation unit 8 of the rotor 6 so that the vertical direction of the measurement cell 1 is perpendicular to the rotation center axis 9 of the rotor. The centrifugal separator 5 is operated to rotate the rotor 6 at a constant rotational speed. The toner adhering to the sample substrate 2 receives a centrifugal force corresponding to the rotational speed, and when the centrifugal force received by the toner is larger than the adhesive force between the toner and the sample surface 2a, the toner is separated from the sample surface 2a, and the adhering surface It adheres to 3a.

  The centrifugal force Fc received by the toner is obtained from equation (4) using the weight m of the toner, the rotational speed f (rpm) of the rotor, and the distance r from the central axis of the rotor to the toner adhesion surface of the sample substrate.

トナーの重量ｍは、トナーの真比重ρ、円相当径ｄを用いて、式(５)より求められる。

The weight m of the toner is obtained from the equation (5) using the true specific gravity ρ of the toner and the equivalent circle diameter d.

式(４)と式(５)より、トナーの受ける遠心力Ｆcは、式(６)から求められる。

From the expressions (4) and (5), the centrifugal force Fc received by the toner can be obtained from the expression (6).

遠心分離終了後、保持部材７をロータ６の試料設置部８から取り出し、保持部材７のセル保持部７ｂから測定セル１を取り出す。受け基板３を交換し、測定セル１を保持部材７に設置し、保持部材７をロータ６に設置し、ロータ６を前回よりも高回転数で回転させる。トナーの受ける遠心力が前回よりも大きくなり、付着力の大きなトナーが、トナーが試料面２ａから分離して付着面３ａに付着する。遠心分離装置の設定回転数を低回転数から高回転数へ変えて同様の操作を実施することにより、各回転数で受ける遠心力と付着力の大小関係に応じて、試料面２ａ上のトナーが付着面３ａに移動する。

After completion of the centrifugation, the holding member 7 is taken out from the sample setting portion 8 of the rotor 6, and the measurement cell 1 is taken out from the cell holding portion 7 b of the holding member 7. The receiving substrate 3 is replaced, the measurement cell 1 is installed on the holding member 7, the holding member 7 is installed on the rotor 6, and the rotor 6 is rotated at a higher rotational speed than the previous time. The centrifugal force received by the toner becomes larger than the previous time, and the toner having a large adhesion force separates from the sample surface 2a and adheres to the adhesion surface 3a. By performing the same operation by changing the set rotational speed of the centrifugal separator from a low rotational speed to a high rotational speed, the toner on the sample surface 2a is changed according to the magnitude relationship between the centrifugal force and the adhesive force received at each rotational speed. Moves to the attachment surface 3a.

After centrifuging for all the set rotation speeds, the particle size of the toner adhering to the adhesion surface 3a of the receiving substrate 3 at each rotation speed is measured. The toner particle size is measured by observing the toner on the adhesion surface 3a with an optical microscope, inputting the image of the adhesion surface to the image processing device through a CCD camera, and measuring the particle size of each toner using the image processing device. Can do. Since the adhesion force of the toner separated at a certain rotational speed is smaller than the centrifugal force at the rotational speed at which the toner is separated and larger than the centrifugal force at the rotational speed before separation, the centrifugal force of both is calculated by equation (4). The average value was defined as the toner adhesion F. The average value F was calculated from F = 10 ^A by calculating the arithmetic average value A for the common logarithm of the adhesive force of each toner.

  The adhesion force between the toner and the photoconductor is composed of a non-electrostatic adhesion force that does not depend on the toner charge amount such as van der Waals force or liquid cross-linking force and an electrostatic adhesion force that depends on the charge amount of the toner. The non-electrostatic adhesion force depends on the geometric structure of the contact area between the toner and the photoreceptor. In particular, the magnitude of the radius of curvature of the toner surface in the contact area with the photoreceptor is an important factor that determines the magnitude of non-electrostatic adhesion. Since the coating of the surface of the toner base particles (toner particles to which no external additive is added) with an external additive can greatly change the radius of curvature of the toner surface, it is an effective means for controlling the non-electrostatic adhesion force. Become. The external additive coverage is defined by the area of the external additive in the surface area of the toner base particles, and can be measured by image analysis of an electron micrograph of the toner. As a result of measuring the adhesion force of various toners, the inventors of the present invention have a tendency that the non-electrostatic adhesion force decreases as the external additive coverage increases, and saturates above a certain external additive coverage. It has been found that the dependency of the non-electrostatic adhesion force on the external additive coverage varies depending on the shape of the toner, the particle size of the external additive, the material, and the like.

  Further, as a result of measuring the adhesion force of various toners, the present inventors determined that the electrostatic adhesion force between the toner and the photoreceptor depends on the toner charge amount, but is not determined only by the toner charge amount. It has been found that the toner shape and constituent materials, particularly the geometric structure of the toner surface and the chargeability of the material existing on the surface, are affected. The toner surface treatment with an external additive can greatly change the geometric structure and chargeability of the toner surface. The inventors of the present invention have an electrostatic adhesion force that depends on the constituent material, shape, etc. of the toner, but depends largely on the external additive coverage, and tends to decrease as the external additive coverage increases. It has been found that the dependency of the electric adhesion force on the external additive coverage varies depending on the shape of the toner, the particle size of the external additive, the material, and the like.

  In order to make the F / Q of the irregular toner smaller than the F / Q of the spherical toner, it is necessary to decrease the F of the irregular toner or increase the Q. However, F depends on the Q and increases the Q. Then, F will also become large. For this reason, it is desirable to decrease F without increasing Q. As described above, by making the external additive coverage of the amorphous toner larger than the external additive coverage of the spherical toner, the F of the amorphous toner can be made smaller than the F of the spherical toner.

  Next, the toner used in the image forming apparatus of the present invention will be described.

  As the irregular toner used in the present invention, a toner having an average value of the shape factor SF1 represented by the following formula (7) of 130 or more, preferably 140 or more is desirable. A pulverized toner or the like prepared by melting and kneading an agent and the like after mixing and stirring, and pulverizing and classifying is preferably used. By using a toner having an SF1 average value of 130 or more, preferably 140 or more, an irregular toner, an effect of improving the cleaning failure can be obtained. When the SF1 average value of 130 or less, an effect of improving the cleaning failure can be obtained. Cannot be obtained.

面積はトナーの投影面積、最大長はトナーの投影像における最大長を示している。

The area indicates the projected area of the toner, and the maximum length indicates the maximum length in the projected image of the toner.

  Further, as the spherical toner used in the present invention, a toner having an average value of SF1 of 100 to 130, preferably 100 to 120 is desirable, and a toner that is spheroidized in a manufacturing process or a process after manufacturing is preferable. Used for. By using toner having a spherical toner SF1 average value of 100 to 130, preferably 100 to 120, an effect of improving the transfer efficiency can be obtained. When the SF1 average value is 130 or more, the transfer efficiency is improved. The effect is not obtained.

  The toner spheroidized in the post-manufacturing process is, for example, a toner obtained by sphering the pulverized toner by heat or mechanical force, and the toner spheronized in the manufacturing process is, for example, a dispersion polymerization method, a suspension polymerization method, or an emulsification method. A toner produced by a polymerization method such as a polymerization method. In particular, the polymerization method is excellent in terms of toner shape, particle size controllability, productivity, and the like, and is suitable as a method for producing a spherical toner used in the present invention.

  The suspension polymerization method is an oil-soluble polymerization initiator, an emulsification method described later in an aqueous medium in which a colorant, a release agent, etc. are dispersed in a polymerizable monomer and a surfactant, other solid dispersant, and the like are contained. To emulsify and disperse. Thereafter, a polymerization reaction is performed to form particles, and then wet processing for attaching inorganic fine particles to the toner particle surfaces in the present invention may be performed. At that time, it is preferable to treat the toner particles from which excess surfactant and the like are removed by washing.

  Examples of the polymerizable monomer include acrylic acids, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and other acids, acrylamide, By using a part of acrylate or methacrylate having amino group such as methacrylamide, diacetone acrylamide or their methylol compounds, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, dimethylaminoethyl methacrylate, etc. Functional groups can be introduced.

  Further, by selecting a dispersant having an acid group or a basic group as a dispersant to be used, the dispersant can be adsorbed and left on the particle surface to introduce a functional group.

  As an emulsion polymerization method, a water-soluble polymerization initiator and a polymerizable monomer are emulsified in water using a surfactant, and a latex is synthesized by an ordinary emulsion polymerization method. Separately, a dispersion in which a colorant, a release agent and the like are dispersed in an aqueous medium is prepared, and after mixing, the toner is aggregated to a toner size and heat-fused to obtain a toner. Thereafter, wet processing of inorganic fine particles described later may be performed. A functional group can be introduced on the surface of the toner particles by using a latex similar to the monomer that can be used in the suspension polymerization method.

  Among these, since the selectivity of the resin is high, the low-temperature fixability is high, the granulation property is excellent, and the particle size, the particle size distribution, and the shape can be easily controlled. It is preferable that the toner is granulated by emulsifying or dispersing the dispersion in an aqueous medium.

  The toner material solution is obtained by dissolving the toner material in a solvent, and the toner material dispersion liquid is obtained by dispersing the toner material in a solvent.

  Examples of the toner material include an adhesive base obtained by reacting an active hydrogen group-containing compound, a polymer capable of reacting with the active hydrogen group-containing compound, a binder resin, a release agent, and a colorant. And other components such as resin fine particles and a charge control agent as necessary.

  The adhesive base material exhibits adhesiveness to a recording medium such as paper, and is formed by reacting the active hydrogen group-containing compound and a polymer capable of reacting with the active hydrogen group-containing compound in the aqueous medium. It may contain at least a polymer and may further contain a binder resin appropriately selected from known binder resins.

  When the volume average particle diameter D1 of the irregular toner used in the present invention and the volume average particle diameter D2 of the spherical toner are used, the ratio D1 / D2 of D1 and D2 is preferably 0.8 to 1.2. If the difference between D1 and D2 is large, the development characteristics and transfer characteristics of the irregular toner and the spherical toner are greatly different, so that it becomes difficult to control image formation, and the image quality is deteriorated. Further, D1 and D2 are desirably 3 μm to 9 μm, more preferably 4 μm to 8 μm. If D1 and D2 are 3 μm or less, the proportion of fine powder toner having a particle size of 1 μm or less, which is likely to cause image defects, increases, and if it is 9 μm or more, it is difficult to meet the demand for high image quality of electrophotographic images.

  In the present invention, a toner whose surface is coated with an external additive is preferably used. As the external additive used in the present invention, known organic fine particles and inorganic fine particles can be used. Regarding the particle size of the external additive, the average primary particle size is preferably 10 nm to 200 nm. If the average value of the primary particle diameter of the external additive is less than 10 nm, the external additive is buried in the toner due to various stresses in the image forming apparatus, and the effect of the external additive is lost. In addition, when the average primary particle diameter of the external additive exceeds 200 nm, the external additive is easily separated from the toner, and the constituent members of the image forming apparatus such as the photosensitive member are easily damaged by the separated external additive. Moreover, the external addition method of the external additive used for this invention can use the well-known external addition method using various mixing apparatuses, such as a V-type blender, a Henschel mixer, and a mechano-fusion.

  Next, the photoreceptor used in the image forming apparatus of the present invention will be described.

  As the photosensitive member used in the present invention, those having at least a charge generation layer and a charge transport layer formed on a conductive support, and those having a protective layer formed on the charge transport layer are used. As the conductive support and the charge generation layer, any known one can be used. The material of the photoconductor of the present invention may be an inorganic photoconductor material such as selenium and its alloys and amorphous silicon, but an organic photoconductor material is preferred. In addition, an undercoat layer can be provided between the photosensitive layer and the conductive substrate for the purpose of improving the chargeability. As the conductive substrate that can be used in the present invention, known substrates can be used. In order to produce the organic photoreceptor of the present invention, a charge generation layer forming solution prepared by dissolving the charge generation material in an organic solvent or dispersing it with a ball mill, ultrasonic waves, or the like is used for dipping, blade coating, spray coating, etc. The charge transport material may be applied and dried on a substrate by a known method, and the charge transport material may be applied and dried by the method described above.

  Next, the intermediate transfer member used in the present invention will be described.

  There is no restriction | limiting in particular as an intermediate transfer body, According to the objective, it can select suitably from well-known transfer bodies, For example, a transfer belt etc. are mentioned suitably.

  The material of the intermediate transfer member is not particularly limited and can be appropriately selected from known materials according to the purpose. For example, (1) a material having a high Young's modulus (tensile elastic modulus) is used as a single layer belt. PC (polycarbonate), PVDF (polyvinylidene fluoride), PAT (polyalkylene terephthalate), PC (polycarbonate) / PAT (polyalkylene terephthalate) blend material, ETFE (ethylene tetrafluoroethylene copolymer) / PC blend materials, ETFE / PAT blend materials, PC / PAT blend materials, carbon black dispersed thermosetting polyimide, and the like. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation with respect to stress during image formation is small, and registration is not likely to occur particularly during color image formation. (2) A belt having a two- to three-layer structure in which a belt having a high Young's modulus is used as a base layer and a surface layer or an intermediate layer is provided on the outer periphery of the belt. Therefore, the line image has a performance capable of preventing the line image from being lost. (3) Belts having a relatively low Young's modulus using rubber and elastomer, and these belts have an advantage that line images are hardly lost due to their softness. In addition, the belt width is made larger than that of the drive roll and the tension roll, and the elasticity of the belt ear protruding from the roll is used to prevent meandering, so that a low cost can be realized without the need for ribs or meandering prevention devices. .

  The transfer belt manufacturing method is not limited. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which a liquid paint is sprayed to form a film, and a cylindrical mold. These include the dipping method in which the material is dipped in the material solution, the casting method in which it is injected into the inner mold and the outer mold, the method in which the compound is wound around a cylindrical mold and vulcanized and polished. It is not limited and it is common to manufacture a belt combining several manufacturing methods.

  Next, the cleaning blade used in the present invention will be described.

  For the cleaning blade of the present invention, a rubber elastic body, particularly polyurethane rubber is preferably used. Polyurethane rubber is produced by preparing a urethane prepolymer using a polyol and a polyisocyanate, adding a curing agent to the polyurethane prepolymer, injecting it into a predetermined mold, crosslinking and curing, and then aging at room temperature.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
First, the spherical toner used in this embodiment will be described.

  Add 40 parts by weight of styrene monomer, 20 parts by weight of carbon black MA100 (manufactured by Mitsubishi Kasei Co., Ltd.) and 0.5 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator. Into a 500 ml four-necked separable flask equipped with a gas introduction tube and a thermometer, the mixture was stirred for 30 minutes at room temperature under a nitrogen stream, and oxygen in the flask was replaced with nitrogen. Then, it stirred at 60 rpm in a 70 degreeC hot water bath for 6 hours, and graft carbon black was obtained.

Styrene monomer 50 parts by weight n-butyl methacrylate 14.5 parts by weight 1,3-butanediol dimethacrylate 0.5 parts by weight t-butylacrylamide sulfonic acid 3 parts by weight Low molecular weight polyethylene 2 parts by weight (Mitsui Petrochemical Co., Ltd., Mitsui High Wax 210P)
30 parts by weight of the grafted carbon black Next, the above mixture was dispersed for 10 hours by a ball mill. After dissolving 1 part by weight of 2,2'-azobisisobutyronitrile and sodium nitrite in this dispersion, each was added to 250 parts by weight of a 2% aqueous solution of polyvinyl alcohol, and TK homomixer manufactured by Tokushu Kika Co., Ltd. The suspension was obtained by stirring at 4000 rpm for 10 minutes. Put the above suspension into a 500 ml four-necked separable flask equipped with a three-one motor driven stirring blade, cooler, gas inlet tube, and thermometer, and stir at room temperature under a nitrogen stream. Replaced. Thereafter, the mixture was stirred in a hot water bath at 70 ° C. for 5 to 8 hours at about 100 rpm to complete the polymerization, thereby producing suspended polymer particles. 100 parts by weight of the particles are re-dispersed in a mixed solution of water / methanol = 1/1 (weight ratio) so that the solid content is 30%, and H ₄ N (CH ₂ ) ₅ CH═C (C _{2 is} used as a charge control agent. 3 parts by weight of F ₅ ) ₂ was added, and after stirring, filtered and dried, polymer particles A having an average shape factor SF1 of 106 and a volume average particle size of 6.8 μm were obtained. The shape factor SF1 is determined by applying toner to an observation substrate for an electron microscope, coating the observation substrate to which the toner is attached with gold, and observing the toner with an electron microscope (scanning electron microscope S-4500 manufactured by Hitachi, Ltd.). The image was taken into a personal computer, and the projected area and the maximum length of the toner were determined using image processing software (Image-Pro Plus manufactured by Media Cybernetics) and calculated according to Equation (7). The volume average particle size was measured using a particle size measuring device TA-II manufactured by Coulter.

  To the polymer particles A, silica A having an average primary particle size of 20 nm hydrophobized is 0.4% by weight of the toner amount, and silica B having an average primary particle size of 100 nm hydrophobized is the amount of toner. 0.5% by weight of titanium oxide A having an average value of the hydrophobized primary particle size of 18 nm is blended so as to be 0.5% by weight of the amount of toner, and stirred and mixed with a Henschel mixer to obtain spherical toner A. Produced.

  For the prepared toner, an electron microscope image of the toner surface is taken into a personal computer in the same manner as in SF1, and the area of the external additive is measured using image processing software. The area of the external additive relative to the area of the toner surface image is measured. The external additive coverage was determined by calculating the ratio of The average value of the external additive coverage of the spherical toner A was 35.6%.

  Next, the irregular toner used in this embodiment will be described.

Polyester resin (weight average molecular weight 250,000) 80 parts by weight Styrene-methyl methacrylate copolymer 20 parts by weight Acid value rice wax (acid value 15) 5 parts by weight Carbon black (Mitsubishi Kasei Kogyo Co., Ltd., # 44) 8 parts by weight Metal-containing monoazo dye 3 parts by weight A mixture of the above composition was sufficiently stirred and mixed in a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C for about 30 minutes with a roll mill, cooled to room temperature, and then obtained using a hammer mill. The kneaded product was coarsely pulverized to about 1 mm to 2 mm and finely pulverized with a jet mill to obtain amorphous particles B having an average shape factor SF1 of 145 and a volume average particle size of 7.1 μm. Amorphous toner B is prepared by mixing 1.0% by weight of silica A, 1.0% by weight of silica B and 1.2% by weight of titanium oxide A with amorphous particles B, and stirring and mixing with a Henschel mixer. did. As a result of measuring the external additive coverage in the same manner as in the spherical toner A, the average value of the external additive coverage of the irregular toner B was 45.2%.

  Next, the photoconductor used in this embodiment will be described.

  Ball milling 0.4 parts by weight of a bisazo pigment of the following structural formula (8) together with 4 parts by weight of a 5% by weight tetrahydrofuran solution of butyral resin (S-LEC BL-S Sekisui Chemical Co., Ltd.) and 7.6 parts by weight of tetrahydrofuran. After milling, tetrahydrofuran was added to dilute to 2% by weight to prepare a coating solution for forming a charge generation layer. This photosensitive solution was applied to an aluminum photoconductor drum having a diameter of 90 mm by an immersion method and dried to form a charge generation layer.

次に、下記構造式（９）の正孔輸送物質を６．０重量部と、感光体バインダー樹脂としてシクロヘキシリデンビスフェノールポリカーボネート(Ｚポリカ，帝人化成ＴＳ２０５０)９．０重量部を、テトラヒドロフラン６７重量部に溶解し、これを浸漬法で電荷発生層上に塗布・乾燥させて、膜厚が２０μｍの電荷輸送層を形成し、本実施例の有機感光体を作製した。

Next, 6.0 parts by weight of a hole transport material of the following structural formula (9), 9.0 parts by weight of cyclohexylidene bisphenol polycarbonate (Z Polyca, Teijin Chemicals TS2050) as a photoreceptor binder resin, 67 parts by weight of tetrahydrofuran This was dissolved in a portion, and applied and dried on the charge generation layer by an immersion method to form a charge transport layer having a thickness of 20 μm, and an organic photoreceptor of this example was produced.

遠心分離法を用いて、本実施例の球形トナーＡと感光体間、及び不定形トナーＢと感光体間の付着力を測定した。本実施例の有機感光体材料を、アルミ蒸着したＰＥＴフィルム上に塗布して有機感光体膜を形成した。このフィルムを直径７．８ｍｍの円板状に切り出し、遠心分離に使用する試料基板上にプラスチック用接着剤を用いて貼り付けた。球形トナーＡとキャリアを混合した現像剤Ａ及び不定形トナーＢとキャリアを混合した現像剤Ｂを作製し、圧縮空気によって現像剤Ａから球形トナーＡを分離して感光体上に付着させた場合と、現像剤Ｂから不定形トナーＢを分離して感光体上に付着させた場合について、遠心分離法を用いてトナーと感光体間の付着力を測定した。なお、現像剤Ａと現像剤Ｂのキャリアは、リコー製カラー複写機Ｉｍａｇｉｏ Ｃｏｌｏｒ ４０００に用いているキャリアで、各現像剤に対するトナーの比率は５重量％、付着力測定に使用した装置及び測定条件は以下のとおりである。

The adhesion between the spherical toner A and the photoreceptor and the irregular toner B and the photoreceptor in this example was measured using a centrifugal separation method. The organophotoreceptor material of this example was applied on an aluminum vapor deposited PET film to form an organophotoreceptor film. This film was cut into a disk shape having a diameter of 7.8 mm, and attached to a sample substrate used for centrifugation using a plastic adhesive. When developer A in which spherical toner A and carrier are mixed and developer B in which amorphous toner B and carrier are mixed are prepared, and spherical toner A is separated from developer A by compressed air and adhered onto the photoreceptor. For the case where the irregular toner B was separated from the developer B and adhered to the photoreceptor, the adhesion between the toner and the photoreceptor was measured using a centrifugal separation method. The carrier of developer A and developer B is the carrier used in the Ricoh color copier Imagio Color 4000, the ratio of toner to each developer is 5% by weight, and the apparatus and measurement conditions used for measuring the adhesive force Is as follows.

Centrifugal separator: CP100α manufactured by Hitachi Koki (maximum rotational speed: 100,000 rpm, maximum acceleration: 800,000 g)
Rotor: Hitachi Koki angle rotor P100AT
Image processing device: Digital Hyper II Image Hyper II
Sample substrate and receiving substrate: a disc having a diameter of 8 mm and a thickness of 1.5 mm, made of aluminum.

  Spacer: A ring with an outer diameter of 8 mm, an inner diameter of 5.2 mm, and a thickness of 1 mm. The material is aluminum.

  Holding member: A cylinder with a diameter of 13 mm and a length of 59 mm. The material is aluminum.

Distance from the central axis of the rotor to the toner adhesion surface of the sample substrate: 64.5 mm
Setting speed f: 1000, 1600, 2200, 2700, 3200, 5000, 7100, 8700, 10000, 15800, 22400, 31600, 50000, 70700, 86600, 100000 (rpm)
For the above-mentioned developer A and developer B, the average value of the charge amount of one toner particle was obtained from the toner charge amount per unit weight measured by the blow-off method and the toner volume average particle diameter D by the formula (3).

  The value F (A) / Q (A) obtained by dividing the average value F (A) of the adhesion force between the spherical toner A and the photosensitive member of this embodiment by the average value Q (A) of the charge amount of the spherical toner A is 12 5. The value F (B) / Q (B) obtained by dividing the average value F (B) of the adhesion force between the irregular shaped toner B and the photosensitive member by the average value Q (B) of the charge amount of the irregular shaped toner B is The ratio of both (F (B) / Q (B)) / (F (A) / Q (A)) was 0.69.

  The toner and carrier are mixed so that the ratio of the irregular toner B to the mixed toner of the spherical toner A and the irregular toner B is 15% by weight and the ratio of the mixed toner to the developer is 5% by weight. A two-component developer was prepared.

  Using the developer and photoconductor of this example, the Ricoh color copier Imagio Color 4000 was used to measure the transfer rate in primary transfer and to evaluate the cleaning performance of the photoconductor drum. In Image Color 4000, development is a two-component development method, transfer is an intermediate transfer belt method, and a method of developing toner of each color on one photoconductor as shown in FIG. 6 is used. The Imagio Color 4000 was modified to remove the lubricant application mechanism on the photosensitive drum so that the image forming process can be stopped at an arbitrary timing by an external signal.

Develop a solid image of only one color on the photoconductor drum, stop the image forming process during the primary transfer, take out the photoconductor drum unit and the intermediate transfer unit from the copying machine, and develop the toner per unit area developed on the photoconductor Weight (M / A) _PC and (M / A) _T transferred onto the transfer belt were measured by the sack-in method, and the transfer rate was determined from the following equation (10). A transfer rate of 95% or more was considered good.

また、クリーニングの途中で作像プロセスを止め、感光体ドラムユニットを複写機から取り出し、クリーニング性を評価した。クリーニング性の評価は、感光体ドラム上をＣＣＤ顕微鏡カメラ（キーエンス社ハイパーマイクロスコープ）によって観察し、評価見本と比較することによって以下に示す４段階に評価した。

Further, the image forming process was stopped in the middle of cleaning, and the photosensitive drum unit was taken out from the copying machine, and the cleaning property was evaluated. The cleaning property was evaluated by the following four stages by observing the surface of the photosensitive drum with a CCD microscope camera (Keyence Hypermicroscope) and comparing it with an evaluation sample.

4: Good 3: Almost good 2: Slightly bad 1: Bad When the developer and the photoreceptor of this example were used, the transfer rate was 97.5%, and the cleaning property was good.

(Example 2)
Using the spherical toner A and the irregular toner B, the mixing ratio of the irregular toner B is 5% by weight, and the toner and the carrier of Example 1 are mixed so that the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Example 2 was produced. Using the developer of Example 2 and the photoreceptor of Example 1, the transfer rate was measured and the cleaning property was evaluated in the same manner as in Example 1. As a result, the transfer rate was 98.8% and the cleaning property was almost good. was.

(Example 3)
Using the spherical toner A and the irregular toner B, the mixing ratio of the irregular toner B is 25% by weight, and the toner and the carrier of Example 1 are mixed so that the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Example 3 was produced. Using the developer of Example 3 and the photoreceptor of Example 1, the transfer rate was measured and the cleaning property was evaluated in the same manner as in Example 1. As a result, the transfer rate was 96.2% and the cleaning property was good. It was.

(Comparative Example 1)
Using the spherical toner A and the irregular toner B, the mixing ratio of the irregular toner B is 3% by weight, and the toner and the carrier of Example 1 are mixed so that the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Comparative Example 1 was produced. Using the developer of Comparative Example 1 and the photoreceptor of Example 1, the transfer rate was measured and the cleaning property was evaluated in the same manner as in Example 1. As a result, the transfer rate was as good as 99.2%. Sex was a little bad.

(Comparative Example 2)
Using the spherical toner A and the irregular toner B, the toner and the carrier of Example 1 are mixed so that the blend ratio of the irregular toner B is 30% by weight and the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Comparative Example 2 was produced. Using the developer of Comparative Example 2 and the photoreceptor of Example 1, the transfer rate measurement and the cleaning property evaluation were performed in the same manner as in Example 1. As a result, the cleaning property was good, but the transfer rate was 94.1. % Worsened.

Example 4
The amorphous particles B are mixed with 1.5% by weight of silica A, 1.2% by weight of silica B and 1.8% by weight of titanium oxide A, and stirred and mixed with a Henschel mixer to prepare an irregular shaped toner C. did. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner C was 61.3%.

  As in Example 1, the average value F (C) of the adhesion between the irregular toner C and the photoreceptor of Example 1 and the average value Q (C) of the charge amount of the irregular toner C were measured. (C) / Q (C) was 5.6, and (F (C) / Q (C)) / (F (A) / Q (A)) was 0.44.

  Using the spherical toner A and the irregular toner C, mixing the toner and the carrier of Example 1 so that the mixing ratio of the irregular toner C is 15% by weight and the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Example 4 was produced. Using the developer of Example 4 and the photoreceptor of Example 1, the transfer rate was measured and the cleaning property was evaluated in the same manner as in Example 1. As a result, the transfer rate was 98.3% and the cleaning property was good. It was.

(Comparative Example 3)
The amorphous particles B are mixed with 0.7% by weight of silica A, 0.8% by weight of silica B and 0.8% by weight of titanium oxide A, and stirred and mixed with a Henschel mixer to prepare an irregular shaped toner D. did. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner D was 34.6%.

  As in Example 1, the average value F (D) of the adhesion between the irregular shaped toner D and the photoreceptor of Example 1 and the average value Q (D) of the charge amount of the irregular shaped toner D were measured. (D) / Q (D) was 12.1, and (F (D) / Q (D)) / (F (A) / Q (A)) was 0.97.

  Using the spherical toner A and the irregular toner C, mixing the toner and the carrier of Example 1 so that the mixing ratio of the irregular toner C is 15% by weight and the ratio of the mixed toner to the developer is 5% by weight. Thus, a two-component developer of Comparative Example 3 was produced. Using the developer of Comparative Example 3 and the photoreceptor of Example 1, the transfer rate measurement and the cleaning property evaluation were performed in the same manner as in Example 1. As a result, the cleaning property was good, but the transfer rate was 93.8. % Worsened.

（実施例５）
本実施例に使用した各色の球形トナーについて説明する。
冷却管、攪拌機および窒素導入管の付いた反応槽中に、ビスフェノールＡエチレンオキサイド２モル付加物７２４部、イソフタル酸２７６部およびジブチルチンオキサイド２部を入れ、常圧で２３０℃、８時間反応させた後、１０〜１５ｍｍＨｇの減圧下で５時間反応させた。これを１６０℃まで冷却して、３２部の無水フタル酸を加え２時間反応させた。更に、これを８０℃まで冷却し、酢酸エチル中にてイソホロンジイソシアネート１８８部と２時間反応を行いイソシアネート含有プレポリマーを得た。得られたプレポリマー２６７部と、イソホロンジアミン１４部とを５０℃で２時間反応させ、重量平均分子量６４０００のウレア変性ポリエステルを得た。同様にビスフェノールＡエチレンオキサイド２モル付加物７２４部、テレフタル酸２７６部を常圧下、２３０℃で８時間重縮合し、次いで１０〜１５ｍｍＨｇの減圧で５時間反応して、ピーク分子量５０００の変性されていないポリエステルを得た。前記ウレア変性ポリエステル２００部と、前記変性されていないポリエステル８００部とを、酢酸エチル／エチルメチルケトン（ＭＥＫ）（１／１）混合溶剤２０００部に溶解、混合し、トナーバインダーの酢酸エチル／ＭＥＫ溶液を得た。一部減圧乾燥し、トナーバインダーを単離した。Ｔｇは６２℃であった。ビーカー内に前記トナーバインダーの酢酸エチル／ＭＥＫ溶液２４０部、ペンタエリスリトールテトラベヘネート（融点８１℃、溶融粘度２５ｃｐｓ）２０部、銅フタロシアニンブルー顔料４部を入れ、ＴＫ式ホモミキサーで６０℃、１２０００ｒｐｍで攪拌し、均一に溶解、分散させた。次いで、ビーカー内にイオン交換水７０６部、ハイドロキシアパタイト１０％懸濁液（日本化学工業(株)製スーパタイト１０）２９４部、ドデシルベンゼンスルホン酸ナトリウム０．２部を入れ均一に溶解した後に、６０℃に昇温し、ＴＫ式ホモミキサーで７８００ｒｐｍに攪拌しながら、前記トナー材料溶液を投入し１０分間攪拌した。次いで、これらの混合液を９８℃まで昇温して溶剤を除去し、濾別、洗浄、乾燥した後、風力分級し、着色粉体を得た。得られた着色粉体１００部と、帯電制御剤（オリエント化学社製ボントロンＥ−８４）０．２部とをＱ型ミキサー（三井鉱山社製）に仕込み、体積が容器内容積の１／２以下のタービン型羽根を周速５０ｍ／ｓに設定し、２分間運転、１分間休止を５サイクル行い、合計の処理時間を１０分間とし、最終的に形状係数ＳＦ１の平均値が１１２、体積平均粒径が５．７μｍの重合粒子Ｃが得られた。

(Example 5)
The spherical toner of each color used in this example will be described.
724 parts of bisphenol A ethylene oxide 2-mole adduct, 276 parts of isophthalic acid and 2 parts of dibutyltin oxide are placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and reacted at 230 ° C. for 8 hours at normal pressure. And then reacted for 5 hours under a reduced pressure of 10 to 15 mmHg. This was cooled to 160 ° C., 32 parts of phthalic anhydride was added and reacted for 2 hours. Furthermore, this was cooled to 80 ° C. and reacted with 188 parts of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-containing prepolymer. 267 parts of the obtained prepolymer and 14 parts of isophoronediamine were reacted at 50 ° C. for 2 hours to obtain a urea-modified polyester having a weight average molecular weight of 64,000. Similarly, 724 parts of bisphenol A ethylene oxide 2-mole adduct and 276 parts of terephthalic acid were polycondensed at 230 ° C. for 8 hours under normal pressure, and then reacted for 5 hours at a reduced pressure of 10 to 15 mmHg. No polyester was obtained. 200 parts of the urea-modified polyester and 800 parts of the unmodified polyester are dissolved and mixed in 2000 parts of an ethyl acetate / ethyl methyl ketone (MEK) (1/1) mixed solvent, and the toner binder ethyl acetate / MEK is mixed. A solution was obtained. A portion was dried under reduced pressure to isolate the toner binder. Tg was 62 ° C. In a beaker, 240 parts of an ethyl acetate / MEK solution of the toner binder, 20 parts of pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 25 cps), 4 parts of copper phthalocyanine blue pigment were placed, and 60 ° C. with a TK homomixer. The mixture was stirred at 12000 rpm and uniformly dissolved and dispersed. Next, after 706 parts of ion-exchanged water, 294 parts of hydroxyapatite 10% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.) and 0.2 part of sodium dodecylbenzenesulfonate were uniformly dissolved in a beaker, The temperature was raised to 0 ° C., and the toner material solution was added and stirred for 10 minutes while stirring at 7800 rpm with a TK homomixer. Subsequently, these mixed liquids were heated up to 98 degreeC, the solvent was removed, it filtered, wash | cleaned and dried, and then air-classified, and colored powder was obtained. 100 parts of the obtained colored powder and 0.2 part of a charge control agent (Bontron E-84 manufactured by Orient Chemical Co., Ltd.) were charged into a Q-type mixer (manufactured by Mitsui Mining Co., Ltd.), and the volume was ½ of the container internal volume. The following turbine type blades were set to a peripheral speed of 50 m / s, operated for 2 minutes, and suspended for 1 minute for 5 cycles. The total treatment time was 10 minutes, and finally the average value of the shape factor SF1 was 112, volume average Polymerized particles C having a particle size of 5.7 μm were obtained.

  Silica A is blended with the polymer particles C so that the amount of toner is 0.7% by weight, silica B is 0.7% by weight of toner, and titanium oxide A is 0.8% by weight of toner. A cyan spherical toner E was prepared by stirring and mixing with a mixer. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the spherical toner E was 43.8%.

  In the production process of the polymer particles C, 8 parts of a quinacridone-based magenta pigment is used instead of 4 parts of the copper phthalocyanine blue pigment, and the polymer particles C are produced in the same manner. Particle D was obtained. The polymer particles D are blended so that silica A is 0.5% by weight of the toner amount, silica B is 0.6% by weight of the toner amount, and titanium oxide A is 0.6% by weight of the toner amount. And a magenta spherical toner F was produced. As a result of measuring the external additive coverage as in Example 1, the average value of the external additive coverage of the spherical toner F was 42.6%.

  In the production process of the polymer particles C, 10 parts of a disazo yellow pigment was added instead of 4 parts of the copper phthalocyanine blue pigment, and the polymer particles C were produced in the same manner. Particle E was obtained. The polymer particles E are blended so that silica A is 0.5% by weight of the toner amount, silica B is 0.6% by weight of the toner amount, and titanium oxide A is 0.6% by weight of the toner amount. And a spherical toner G for yellow was prepared. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the spherical toner F was 41.9%.

  In the production process of the polymer particles C, 10 parts of carbon black was used instead of 4 parts of the copper phthalocyanine blue pigment, and the polymer particles F were produced in the same manner. The polymer particles F having an average value of the shape factor SF1 of 114 and a volume average particle diameter of 5.7 μm. was gotten. The polymer particles F are blended so that silica A is 0.5% by weight of the toner amount, silica B is 0.6% by weight of the toner amount, and titanium oxide A is 0.6% by weight of the toner amount. The spherical toner H for black was prepared by stirring and mixing. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the spherical toner F was 42.1%.

  Next, the amorphous toner of each color used in this embodiment will be described.

Polyester resin 100 parts by weight Copper phthalocyanine blue pigment 4 parts by weight Zinc salicylate derivative 4 parts by weight The mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer, and then heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes using a roll mill. After cooling to about 1, the kneaded material obtained using a hammer mill is roughly pulverized to about 1 mm to 2 mm, and finely pulverized with a jet mill. The average value of the shape factor SF1 is 142, and the volume average particle size is 6.3 μm. Amorphous particles G were obtained. The amorphous particles G were mixed with 1.3% by weight of silica A, 1.2% by weight of silica B, and 1.5% by weight of titanium oxide A. Toner I was prepared. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner I was 51.8%.

  In the production process of the irregular-shaped particles G, 8 parts of quinacridone-based magenta pigment is put in place of 4 parts of the copper phthalocyanine blue pigment, and the same is produced, and the average value of the shape factor SF1 is 143 and the volume average particle diameter is 6.2 μm. Amorphous particles H were obtained. The amorphous particles H are mixed with 1.1% by weight of silica A, 1.1% by weight of silica B, and 1.3% by weight of titanium oxide A, and are stirred and mixed with a Henschel mixer to form an irregular shape for magenta. Toner J was prepared. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner J was 51.1%.

  In the production process of the irregular-shaped particles G, 10 parts of a disazo yellow pigment was used instead of 4 parts of the copper phthalocyanine blue pigment, and the same was produced. The average value of the shape factor SF1 was 142, and the volume average particle diameter was 6.2 μm. Amorphous particles I were obtained. The amorphous particles I were mixed with 1.1% by weight of silica A, 1.1% by weight of silica B, and 1.3% by weight of titanium oxide A, and the mixture was stirred and mixed by a Henschel mixer. Toner K was prepared. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner K was 50.8%.

  In the production process of the amorphous particles G, 10 parts of carbon black is used instead of 4 parts of the copper phthalocyanine blue pigment, and the same process is performed. The amorphous form has an average value of the shape factor SF1 of 142 and a volume average particle diameter of 6.2 μm. Particle J was obtained. The amorphous particles J were mixed with 1.1% by weight of silica A, 1.1% by weight of silica B, and 1.3% by weight of titanium oxide A. Toner L was prepared. As a result of measuring the external additive coverage in the same manner as in Example 1, the average value of the external additive coverage of the irregular toner L was 50.9%.

  Each developer is prepared so that the ratio of the toner used in the Ricoh color copier Imagio Neo C600, the spherical toner and the irregular toner of each color is 5% by weight. Then, the average values F (E) to F (H) of the adhesion between the spherical toners E to H and the photosensitive member of Example 1 and the average values Q (E) to Q (H) of the charge amount are measured, and the spherical shape of each color is measured. Table 2 shows the results of the toner F / Q. Further, the average values F (I) to F (L) of the adhesion between the irregular toners I to L and the photosensitive member of Example 1 and the average values Q (I) to Q (L) of the charge amount are measured, and each color is measured. Table 2 shows the results of calculating the F / Q of the irregular toner. In addition, Table 2 shows the results of determining the ratio of the F / Q of the irregular toner and the F / Q of the spherical toner for each color.

  For each color spherical toner and irregular toner, the mixing ratio of the irregular toner is 15% by weight, and the ratio of the mixed toner to the carrier and developer used in the Ricoh color copier Imagio Neo C600 is 5% by weight. The two-component developer of Example 5 corresponding to each color was prepared. Further, the diameter of the aluminum photoconductive drum in Example 1 was changed from φ90 mm to φ60 mm, and the photoconductive drum of this example was produced in the same manner as in Example 1.

  Using the developer and photoconductor of this example, the Ricoh color copier Imagio Neo C600 was used to measure the transfer rate in the primary transfer and to evaluate the cleaning performance of the photoconductor drum. The Image Neo C600 uses a two-component development system for development, an intermediate transfer belt system for transfer, and uses a tandem system as shown in FIG. The Imagio Neo C600 was modified to remove the cleaning brush and lubricant application mechanism from each photoconductor drum unit (PCU) so that the image forming process can be stopped at an arbitrary timing by an external signal. Develop a solid image of only one color, stop the process before secondary transfer from the intermediate transfer belt to the recording paper, take out the PCU and intermediate transfer unit used for development from the copier, and transfer them in the same way as in Example 1. The rate was measured. The cleaning property was also evaluated in the same manner as in Example 1 for the PCU photosensitive drum used for development. Table 2 shows the evaluation results for each color toner.

  As shown in Table 2, for all color toners, the F / Q ratio of the amorphous toner and the spherical toner, and the mixing ratio of the amorphous toner are within the scope of the claims, and the transfer rate and cleaning properties are improved. .

(Comparative Example 4)
In the spherical toner and the irregular toner of each color in Example 5, the mixing ratio of the irregular toner is 2% by weight, and the ratio of the mixed toner to the carrier and developer used in the Ricoh color copier Imageo Neo C600 is set as follows. The two-component developer of Comparative Example 4 corresponding to each color was prepared by mixing at 5% by weight. Table 2 shows the results of carrying out the transfer rate measurement and the cleaning property evaluation in the same manner as in Example 5 using the developer of Comparative Example 4 and the photoreceptor of Example 5. As shown in Table 2, for all color toners, the transfer rate was good, but the cleaning properties were slightly poor.

(Comparative Example 5)
In the spherical toner and the irregular toner of each color in Example 5, the mixing ratio of the irregular toner is 40% by weight, and the ratio of the mixed toner to the carrier and developer used in the Ricoh color copier Imageo Neo C600 is set as follows. The two-component developer of Comparative Example 5 corresponding to each color was prepared by mixing so as to be 5% by weight. Table 2 shows the results of carrying out the transfer rate measurement and the cleaning property evaluation in the same manner as in Example 5 using the developer of Comparative Example 5 and the photoreceptor of Example 5. As shown in Table 2, the cleaning properties of all color toners were good, but the transfer rate deteriorated.

以上のように、不定形トナーと球形トナーのＦ／Ｑの比、不定形トナーの混合比が、本発明の請求項に記載した範囲内にある場合は、転写率、クリーニング性共に良好であるが、請求範囲外にある場合は、転写率またはクリーニング性が悪化する。

As described above, when the F / Q ratio of the irregular toner and the spherical toner and the mixing ratio of the irregular toner are within the range described in the claims of the present invention, both the transfer rate and the cleaning property are good. However, if it is outside the scope of claims, the transfer rate or the cleaning property deteriorates.

  Therefore, in the present invention, the toner of the irregular shape is mixed with the spherical toner, and the ratio of the adhesion between the image carrier and the toner and the charge amount per one toner particle is controlled, so that the transfer efficiency is high and the cleaning failure, etc. Therefore, it is possible to provide a high-quality image forming apparatus that does not cause image defects.

  Further, according to the present invention, for each color toner used for forming a color image, an amorphous toner is mixed with a spherical toner, and the ratio between the adhesion between the image carrier and the toner and the charge amount per toner particle is controlled. Accordingly, it is possible to provide a high-quality color image forming apparatus that has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

  In addition, the present invention can provide a high-quality image forming apparatus that has high transfer efficiency and does not cause image defects due to poor cleaning, etc., by making the mixing ratio of the amorphous toner within a certain range. By controlling the external additive coverage of irregular and spherical toners, the adhesion between the image carrier and the toner can be controlled, the transfer efficiency is high, and high-quality images that do not cause image defects due to poor cleaning, etc. A forming apparatus can be provided.

  Furthermore, according to the present invention, it is possible to suppress the cleaning failure and improve the transfer efficiency by defining the SF1 of the irregular toner and the spherical toner.

  The present invention also makes it possible to suppress the difference between the development characteristics and transfer characteristics of both toners by making the particle sizes of the irregular toner and the spherical toner comparable, and to suppress a decrease in image quality. By making it within this range, it is possible to suppress degradation of image quality, and by making the particle size of the external additive within a certain range, it is possible to ensure the durability of the developer and prevent damage to the photoconductor, etc. .

  In addition, the present invention can provide a high-quality image forming toner that is used in the image forming apparatus of the present invention and has high transfer efficiency and does not cause image defects due to poor cleaning or the like.

  Further, the toner used in the developer is a high-quality toner that has high transfer efficiency and does not cause image defects due to poor cleaning, etc., the photosensitive member, the charging unit, the developing unit containing the developer, and the cleaning unit A process cartridge that integrally supports at least one means selected from the above and can be attached to and detached from the main body of the image forming apparatus can be provided.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

It is explanatory drawing of the measurement cell in the powder adhesive force measuring apparatus which concerns on this invention. It is a partial cross section side view of the centrifuge of the powder adhesive force measuring apparatus which concerns on this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic block diagram which shows an example of the image development apparatus of this invention. 1 is a schematic configuration diagram illustrating an example of a color image forming apparatus of the present invention. 1 is a schematic configuration diagram illustrating an example of a color image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement cell 2 Sample substrate 2a Sample surface 3 Receiving substrate 3a Adhesion surface 4 Spacer 5 Centrifugal device 6 Rotor 7 Holding member 7a Rod-shaped part 7b Cell holding part 7c Hole part 7d Installation fixing part 8 Sample installation part 9 Rotation center axis 21 Photosensitive Body drum 22 Charging device 23 Exposure device 24 Developing device 25 Transfer device 26 Recording medium 27 Fixing device 28 Fixing roller 29 Pressure roller 30 Cleaning device 31 Static eliminating device 41 Screw 42 Developing sleeve 43 Doctor blade 51a Photosensitive drum 51b Charging device 51c Exposure Device 51d Developing device 51e Transfer device 51f Cleaning device 51g Static elimination device 51, 52, 53, 54 Image forming unit 55 Intermediate transfer belt 56 Transfer device 57 Recording material 58 Cleaning device 61 Photosensitive drum 62 Charging device 63 Exposure device 64 Developing device 64Y, 64M, 64C, 64B Developing device 65 Transfer device 64a, 64b, 64c, 64d Transfer roller 67 Intermediate transfer belt 68 Cleaning device 69 Recording material 70 Fixing device 71 Fixing roller 72 Pressure roller 73 Cleaning device 74 Static elimination device

Claims (13)

At least means for forming an electrostatic latent image on the image carrier, developing means for forming a toner image on the image carrier, means for transferring the toner image formed on the image carrier to a recording medium, and cleaning In an image forming apparatus having a step of removing toner remaining on the image carrier using a blade,
As the toner, powder mixed with spherical toner and irregular toner is used,
A value F1 / Q1 obtained by dividing the average value F1 of the adhesion force between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, and the interposition between the image carrier and the spherical toner. The ratio F2 / Q2 (F1 / Q1) / (F2 / Q2) obtained by dividing the average value F2 of the adhesion force by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. Image forming apparatus. At least means for forming an electrostatic latent image on the image carrier, a plurality of developing means for forming toner images of different colors on the image carrier, and a toner image formed on the image carrier as a recording medium In a color image forming apparatus having a means for transferring and a step of removing toner remaining on the image carrier using a cleaning blade,
As each toner, powder mixed with spherical toner and irregular toner is used,
For each toner, a value F1 / Q1 obtained by dividing the average value F1 of the adhesion between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, the image carrier and the toner A ratio (F1 / Q1) / (F2 / Q2) of F2 / Q2 obtained by dividing the average value F2 of the adhesion force between the spherical toners by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. An image forming apparatus. At least means for forming an electrostatic latent image on the image carrier, developing means for forming a toner image on the image carrier, means for transferring the toner image formed on the image carrier to a recording medium, and An image forming apparatus in which a plurality of image forming elements having a step of removing toner remaining on the image carrier using a cleaning blade are arranged, and a color image is formed using a plurality of colors of toner for each image forming element In
As the toner used for each image element, powder mixed with spherical toner and irregular toner is used,
In each of the image elements, a value F1 / Q1 obtained by dividing the average value F1 of the adhesion between the image carrier and the amorphous toner by the average value Q1 of the charge amount per particle of the irregular toner, the image carrier, A ratio (F1 / Q1) / (F2 / Q2) of F2 / Q2 obtained by dividing the average value F2 of the adhesion between the spherical toners by the average value Q2 of the charge amount per one particle of the spherical toner is 0.8 or less. An image forming apparatus.   The transfer means is an intermediate transfer body on which a toner image formed on an image carrier is primarily transferred, and a transfer means for secondary transfer of the toner image carried on the intermediate transfer body to a recording medium. The image forming apparatus according to any one of claims 1 to 3.   The image forming apparatus according to claim 1, wherein a mixing ratio of the irregular toner in the mixed powder is 5 to 25%.   6. The image forming apparatus according to claim 1, wherein the external additive coverage of the irregular toner is larger than the external additive coverage of the spherical toner.   The image forming apparatus according to any one of claims 1 to 6, wherein an average value of the shape factor SF1 of the irregular toner is 130 or more.   The image forming apparatus according to any one of claims 1 to 7, wherein an average value of the shape factor SF1 of the spherical toner is 100 to 130.   The ratio D1 / D2 of the volume average particle diameter D1 of the irregular toner and the volume average particle diameter D2 of the spherical toner is 0.8 to 1.2. The image forming apparatus described.   10. The image forming apparatus according to claim 1, wherein a volume average particle diameter of the irregular toner and the spherical toner is 3 to 9 μm.   11. The image forming apparatus according to claim 1, wherein an average value of primary particle diameters of external additives covering the irregular toner and the spherical toner is 10 nm to 200 nm.   An image forming toner for use in the image forming apparatus according to claim 1. A process cartridge that integrally supports at least one means selected from a photosensitive member, a charging means, a developing means containing developer, and a cleaning means, and is detachable from the main body of the image forming apparatus. The process cartridge according to claim 12, wherein the toner used in the process is the toner according to claim 12.

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