JP5240551B2 - Developing device, process cartridge, image forming apparatus - Google Patents

Description

  The present invention relates to a developing device, an image forming apparatus such as a copying machine, a facsimile, and a printer using the developing device, and a process cartridge.

  Conventionally, a one-component developing device using a developer made of nonmagnetic or magnetic toner is known. In the one-component developing device, the developer in the developer container is supplied to the developer carrying member by the developer supplying member, and a developer regulating member such as a metal thin plate is brought into press contact with the developer carrying member, and the developer carrying member is placed on the developer carrying member. The developer is triboelectrically charged and thinned to develop the electrostatic latent image formed on the image carrier. Further, as the one-component developing device, a so-called vertical developing device is known in which a large space developer accommodating portion is disposed above a developer supplying member to reduce the thickness of the developing device. The vertical developing device is effective in reducing the overall size of an image forming apparatus in which four developing devices are arranged in parallel as in the tandem type.

  However, in the configuration of the vertical developing device, the developer supply direction from the developer storage portion to the developer supply member is the same as the gravity direction, and the developer supply amount varies depending on the developer storage amount. Is difficult to supply. As a result, development failure such as fogging due to excessive uncharged developer and image failure such as density fluctuation are caused. Furthermore, in recent years, the toner particle size has been reduced along with the improvement in image quality, and the degree of toner aggregation tends to increase. If the device is not used or left for a while, the toner in the developing device aggregates due to gravity, and only the toner in the immediate vicinity of the developer supply member and developer carrier is used during subsequent use. Will be used, causing a so-called “cavitation” phenomenon. As a result, there may be a problem of density reduction due to poor supply of toner or a problem of blurring. Patent Document 1 (FIG. 7) describes that a vertical developing device is divided into upper and lower parts in order to reduce the pressure of toner applied to a developer supply member. Japanese Patent Application Laid-Open No. H11-260260 describes a developer developing member provided in the vicinity of a developer supply member in a vertical developing device in order to prevent aggregation of the developer.

  FIG. 9 shows a schematic configuration diagram of an example of a vertical developing device. The developing device 100 in FIG. 9 rotates with a developing roller 102 as a developer carrying member, a doctor blade 103 that presses and contacts the developing roller 102 to thin the toner layer, and abuts against the developing roller 102. And a supply roller 410 as a developer supply member. Above the supply roller 104, a vertically long developer accommodating portion 105 that accommodates toner is disposed. A first agitator 106 and a first agitator 106 which are disposed in the developer accommodating portion 105 in the vicinity of the supply roller 104 and supply the toner to the supply roller 104 while stirring the toner in the developer accommodating portion 105. And a second agitator 107 that is disposed above and stirs the toner in the developer accommodating portion 105. The first agitator 106 includes a rotating shaft 106a and two working shafts 106b and 106c that are a predetermined distance from the rotating shaft center 106A. The second agitator 107 includes a rotating shaft 107a and two working shafts 107b and 107c that are a predetermined distance from the rotating shaft center 107A. The toner in the developer container 105 stirred by the second agitator 107 is supplied to the supply roller 104 while being stirred by the rotation of the first agitator 106. The toner supplied to the supply roller 104 is supplied to the developing roller 102. The toner supplied to the developing roller 102 is thinned by the doctor blade 103 and then conveyed to a developing area facing the photosensitive drum 101 as an image carrier. In the development area, toner is supplied to the electrostatic latent image formed on the photosensitive drum 101 for development.

JP 2003-5487 A JP 2001-194 483 A

  In the developing device 100 of FIG. 9, for example, the two working shafts 106b and 106c of the first agitator 106 are provided at an equal distance from the rotation shaft center 106A. For this reason, the toner inside the stirring region that receives the stirring action directly from the action shafts 106b and 106c is not directly affected by the action shafts 106b and 106c, so that it is difficult to stir. In particular, the toner near the rotating shaft 106a stays. Cheap.

  When the toner whose charging property has deteriorated due to toner deterioration is charged on the developing roller 102, the toner layer on the photosensitive drum 101 becomes thin. However, if the toner layer gradually changes from the initial state, the change is not noticeable. On the other hand, when the toner that has not deteriorated falls on the supply roller 104 and enters the doctor blade 103 while the toner deterioration is promoted, the toner layer on the photosensitive drum 101 also changes deeply. When the toner layer on the photoconductive drum 101 changes deeply, the image density also increases. When the change suddenly occurs, for example, the leading edge is thin and the trailing edge is dark in one printed matter.

  The present invention has been made in view of the above problems, and an object of the present invention is to supply a developer in a vertical developing device in which a developer containing portion for containing a developer is provided above a developer supplying member. It is an object of the present invention to provide a developing device, an image forming apparatus, and a process cartridge capable of stably supplying a developer to a member and performing a good developing operation.

In order to achieve the above object, the invention of claim 1 is directed to a developer carrier that carries a developer and conveys the developer to a portion opposed to the latent image carrier, and contacts the developer carrier while rotating. A developer supply member that supplies the developer, a developer storage portion that is provided above the developer supply member and stores the developer, and a developer stirring member that stirs the developer in the developer storage portion while rotating The developer stirring member includes a rotation shaft and a plurality of operation shafts that are at different distances from the rotation shaft center and exert a stirring action on the developer in the developer accommodating portion. Tona is, one in which the rotation locus of the operating shaft in the closest distance from the rotation axis center of the operating shaft of said plurality of characterized in that it is a structure passing through the rotation axis center.
According to a second aspect of the present invention, in the developing device of the first aspect, a plurality of the developer agitating members are provided.
According to a third aspect of the present invention, in the developing device according to the first or second aspect , the developer agitating member provided in the vicinity of the developer supply member has a rotation locus of a working shaft at a distance farthest from the rotation axis center. It is arranged at a position where the distance between the outermost periphery and the developer supply member is 1 mm or less.
According to a fourth aspect of the present invention, in the developing device of the first, second, or third aspect , the developer has a volume average particle size of 3 to 8 mm, a volume average particle size (DV), and a number average particle size (DN). And a toner having a ratio (DV / DN) in the range of 1.00 to 1.40.
According to a fifth aspect of the present invention, in the developing device according to the first, second, third, or fourth aspect , the developer has a shape factor SF-1 in the range of 100 to 180, and a shape factor SF-2 of 100 to 180. In this range, the toner is used.
The invention of claim 6 is the developing device according to claim 1, 2, 3, 4 or 5 , wherein the developer includes at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, and a colorant. A toner obtained by cross-linking and / or extending a toner material solution in which a release agent is dispersed in an organic solvent in an aqueous medium is used.
According to a seventh aspect of the present invention, in the process cartridge in which the latent image carrier and the developing means are integrally formed and detachable from the main body of the image forming apparatus, the developing means is the first, second, third, fourth, The developing device of either 5 or 6 is employed.
The invention of claim 8 comprises a latent image carrier, latent image forming means for forming an electrostatic latent image on the latent image carrier, and developing means for developing the latent image on the latent image carrier. In the image forming apparatus, the developing device according to any one of claims 1, 2, 3, 4, 5 or 6 is adopted as the developing means.
In the present invention, the plurality of action shafts of the developer stirring member are provided at different distances from the rotation axis center. Therefore, the area occupied by the rotation trajectory of the action shaft is larger than when there is one action axis or when a plurality of action axes are provided at the same distance from the center of the rotation axis. More developer is received directly. As a result, the area where the developer tends to stay is reduced, and the developer in the developer container can be stably supplied to the developer supply member. In particular, since the rotation trajectory of the working shaft at the closest distance from the center of the rotation axis passes through the center of the rotation axis, the toner in the rotation axis center region where the toner is most likely to stay can be agitated. It can prevent staying.

  According to the present invention, in the vertical developing device in which the developer accommodating portion for accommodating the developer is provided above the developer supplying member, the developer supplying member can be stably replenished with the developer. There is an excellent effect that a developing device, an image forming apparatus, and a process cartridge capable of performing a developing operation can be provided.

  Hereinafter, an embodiment in which the present invention is applied to a developing device employed in a color image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of a color image forming apparatus employing a developing device according to the present embodiment. The color image forming apparatus in FIG. 1 is an image forming apparatus of a tandem type indirect transfer system, and image forming units 20Y, 20M, 20C, and 20K are arranged almost at the center of the machine frame. Each of the image forming units 20Y, 20M, 20C, and 20K includes drum-shaped photoreceptors 1Y, 1M, 1C, and 1K that carry toner images. Here, Y, M, C, and K are subscripts representing yellow, magenta, cyan, and black colors, respectively. An exposure device 21 for forming a latent image on the photoreceptors 1Y, 1M, 1C, and 1K is disposed above the image forming units 20Y, 20M, 20C, and 20K.

  Further, an intermediate transfer belt 30 is installed below the image forming units 20Y, 20M, 20C, and 20K. Primary transfer rollers 31Y, 31M, 31C, and 31K are provided inside the intermediate transfer belt 30 at positions facing the image forming units 20Y, 20M, 20C, and 20K. A secondary transfer device 32 is provided downstream of the primary transfer rollers 31Y, 31M, 31C, and 31K so as to face the surface of the intermediate transfer belt 30. Further, a fixing device 33 is provided downstream of the secondary transfer device 32 with respect to the conveyance direction of the recording medium.

  In each of the image forming units 20Y, 20M, 20C, and 20K, toner images of the respective colors are formed on the respective photoreceptors 1Y, 1M, 1C, and 1K. The color toner images are sequentially transferred onto the intermediate transfer belt 30 on the photoreceptors 1Y, 1M, 1C, and 1K, and a plurality of color toner images are formed on the intermediate transfer belt 30 by superimposing single-color toner images. . The recording medium is timed and supplied to the facing portion between the intermediate transfer belt 30 and the secondary transfer device 32, and the color toner image formed on the surface of the intermediate transfer belt 30 is transferred onto the recording medium. The recording medium on which the toner image has been transferred is peeled off from the intermediate transfer belt 30 and the toner image is fixed by the fixing device 33 to form an image.

  Next, the image forming units 20Y, M, C, and K will be described. Since these image forming units 20Y, 20M, 20C, and 20K have the same configuration and operation except that the color of the toner to be stored is different, the subscripts Y, M, C, and K will be omitted below. I will explain. In the image forming unit 20, a charging device 22, a developing device 23, a cleaning device 24, and the like are disposed around the photoreceptor 1. Further, the photosensitive member 1, the charging device 22, the developing device 23, the cleaning device 24, and the like are integrally formed, and form a process cartridge that can be attached to and detached from the main body of the image forming apparatus, thereby improving maintainability.

  Next, the developing device 23 will be described. FIG. 2 is a schematic configuration diagram illustrating the configuration of the developing device. The developing device 23 in FIG. 2 is a developing device that uses a non-magnetic one-component toner as a developer. The developing device 23 rotates to contact the developing roller 2 as a developer carrying member, the doctor blade 3 that presses and contacts the developing roller 2 to thin the toner layer, and rotates while contacting the developing roller 2. And a supply roller 4 as a developer supply member for supplying toner. The doctor blade 3 is made of an elastic member such as a thin metal plate. The supply roller 4 is made of an elastic member such as polyurethane foam. In addition, a vertically long developer accommodating portion 5 that accommodates toner is disposed above the supply roller 4. A first agitator 6 that is disposed in the developer accommodating portion 5 in the vicinity of the supply roller 4 and supplies the toner in the developer accommodating portion 5 to the supply roller 4 while stirring, above the first agitator 6. And a second agitator 7 for agitating the toner in the developer accommodating portion 5.

  The toner in the developer container 5 is stirred by a second agitator 7 that rotates counterclockwise in the figure, and is supplied to the supply roller 4 by a first agitator 6 that rotates clockwise in the figure. The toner supplied to the supply roller 4 that rotates counterclockwise in the drawing is supplied to the developing roller 2. The toner supplied to the developing roller 2 that rotates counterclockwise in the drawing is thinned by a doctor blade 3 on the way, and then conveyed to a developing area facing the photoreceptor 1. In the development area, toner is supplied to the electrostatic latent image formed on the photoconductor 1 for development. Further, the supply roller 4 scrapes off excess toner from the developing roller 2 downstream of the developing region. The toner scraped off moves to the developer accommodating portion 5 disposed above the supply roller 4 by the flow of the developer due to the rotation of the supply roller 4 and is mixed with the toner in the developer accommodating portion 5. The toner is again supplied to the developing roller 1 through the supply roller 4.

  Next, the first agitator and the second agitator as the developer stirring member will be described. FIG. 3 is an enlarged configuration diagram of a main part for explaining the configuration of the developing device. FIG. 4 is a schematic diagram for explaining the rotation locus of the first agitator. FIG. 5A is a plan view for explaining the configuration of the first agitator, and FIG. 5B is a schematic diagram for explaining the rotation locus of the first agitator. FIG. 6A is a plan view for explaining the configuration of the second agitator, and FIG. 6B is a schematic view for explaining the rotation locus of the second agitator. As shown in FIGS. 3 to 5, the first agitator 6 includes a rotating shaft 6a, a cylindrical action shaft 6b at a distance l from the rotating shaft center 6A, and a cylindrical shape at a distance m from the rotating shaft center 6A. The action shaft 6c. As shown in FIG. 6, the second agitator 7 includes a rotating shaft 7, a cylindrical action shaft 7b at a distance n from the rotating shaft center 7A, and a cylindrical action at a distance o from the rotating shaft center 7A. The shaft 7c is composed of cylindrical action shafts 7d and 7e located at a distance p from the rotation shaft center 7A. At this time, the action shafts 7d and 7e on the outermost periphery may be provided at an equal distance from the rotation shaft center 7A.

  The first and second agitators 6 and 7 configured in this way can generate a centrifugal force by rotating to have a stirring force in the circumferential direction, and can have action shafts 6b, 6c, 7b, 7c, and 7d. , 7e, the toner is dropped into the space. For this reason, the first and second agitators 6 and 7 have a larger stirring force in the vertical direction than the rotating blades made of a screw-like stirring member or a film, and the like. Can be mixed efficiently. In addition, the first agitator 6 has two working shafts 6b and 6c having different distances l and m from the rotation shaft center 6A, so that a stirring region 6B (shown in black) by the working shaft 6b and the working shaft are provided. The agitation region 6C by 6c (black in the figure) is different from each other. Therefore, the first agitator 6 can reduce the area where the toner is likely to stay compared to the agitator having two working axes at the same distance from the center of the rotation axis, and can improve the stirring force of the toner. Further, the second agitator 7 has the four action shafts 7b, 7c, 7d, and 7e having different distances n, o, and p from the rotation axis center 7A, so that the stirring region 7B (black coating) by the action shaft 7b is applied. ), The stirring region 7C (shown in black) by the action shaft 7c, and the stirring region 7DE (shown in black) by the action shafts 7d and 7e are different from each other. For this reason, the second agitator 7 can reduce the area where the toner is likely to stay compared to the agitator having four action axes at the same distance from the center of the rotation axis, and can improve the stirring force of the toner. The shapes of the rotary shafts 6a and 7a and the action shafts 6b, 6c, 7b, 7c, 7d, and 7e are not limited to a cylindrical shape, and the cross-sectional shape may be a polygonal shape. The shaft has a small load on the toner and is excellent in productivity.

  Further, as shown in FIG. 5B, the first agitator 6 according to the present embodiment has a configuration in which the rotation locus 6B of the action shaft 6b closest to the rotation axis center 6A passes through the rotation axis center 6A. It has become. As shown in FIG. 6B, the second agitator 7 is configured such that the rotation locus 7B of the action shaft 7b closest to the rotation axis center 7A passes through the rotation axis center 7A. Here, the center of the rotation axis is different from the center of the action axis. With such a configuration, it is possible to stir the toner in the rotation axis centers 6A and 7A, where the toner is most likely to stay, and to prevent the toner from staying in the rotation axes 6A, 7A.

  As shown in FIG. 2, the developing device 23 is provided with a plurality of agitators 6 and 7 in the developer accommodating portion 5, so that the developing device 23 in the developer accommodating portion 5 is compared with a case where only one agitator is provided. The stirrability of the toner can be improved. When a plurality of agitators are provided, the sizes may be different from each other. By changing the size of the agitator, the first agitator 6 that supplies the toner to the supply roller 4 and the second agitator 7 that circulates the toner in the developer container 5 can be used. it can. As shown in FIG. 3, the first agitator 6 is provided in the vicinity of the supply roller 4 so that the distance between the outermost rotation locus of the first agitator 6 and the supply roller 4 is 1 mm or less. Therefore, the toner can be supplied to the supply roller 4 while being conveyed in the arrow A direction by the rotation of the first agitator 6, and the toner supply performance to the supply roller 4 can be improved. The second agitator 7 has a larger number of operating shafts than the first agitator 6, and the distance from the rotational axis center of the operating shaft that is the outermost periphery is larger, so the stirring force of the toner is larger than that of the first agitator 6. Become.

  In addition, the first and second agitators 6 and 7 shown in FIGS. 5 and 6 are configured such that all the working shafts 6b, 6c, 7b, 7c, 7d, and 7e have the same diameter. However, the diameters of a plurality of action shafts provided to suppress rotational shake may be different from each other. Fig.7 (a) is a top view which shows the structure of the agitator which concerns on another embodiment, (b) is a schematic diagram explaining the rotation locus | trajectory of this agitator. The agitator 8 shown in FIG. 7 is at a distance q from the rotation axis 8a and the rotation axis center 8A, and has a cylindrical action axis 8b having a diameter q and a distance r from the rotation axis center 8A and a diameter smaller than the diameter q. It is comprised from the cylindrical action shaft 8c used as s. Since the agitator 8 configured in this manner has the center of gravity coincident with the rotation axis center 8A, rotational shake is suppressed.

Next, the toner used in this embodiment will be described.
In order to reproduce minute dots of 600 dpi or more, the weight average particle diameter of the toner is preferably 3 to 8 [μm]. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the weight average particle diameter (D4) is less than 3 [μm], phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. When the weight average particle diameter (D4) exceeds 8 [μm], it is difficult to suppress scattering of characters and lines. Moreover, it is preferable that ratio (D4 / D1) of a weight average particle diameter (D4) and a number average particle diameter (D1) exists in the range of 1.00-1.40. The closer (D4 / D1) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

Next, a method for measuring the particle size distribution of toner particles will be described.
Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.

  First, 0.1 to 5 [ml] of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 [mg] of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the weight and number of toner particles or toner using a 100 [μm] aperture as the aperture. Then, the weight distribution and the number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained. As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], particles having a particle size of 2.00 [μm] or more to less than 40.30 [μm] are targeted.

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. FIGS. 8A and 8B are schematic views showing the shape of the toner for explaining the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) 2 / AREA} × (100π / 4) Expression (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.
The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) 2 / AREA} × (100 / 4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

  Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated. When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

  Further, the toner suitably used in the present embodiment is a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. Is a toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.

  Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.
The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; phenol derivatives, oximes, polyisocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyisocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 [wt%], preferably 1 to 30 [wt%], more preferably 2 to 20 [wt%]. If it is less than 0.5 [wt%], the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 [wt%], the low-temperature fixability deteriorates. The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated. The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.
When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).
In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond. The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient. In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenol-based condensate E-89 (above, manufactured by Orient Chemical Industries), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, manufactured by Hodogaya Chemical Co., Ltd.)
Quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (from Hoechst), LRA-901, boron complex LR-147 (manufactured by Nippon Carlit), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ⁻³ to 2 [μm], particularly preferably 5 × 10 ^{−3 to} 0.5 [μm]. Moreover, it is preferable that the specific surface area by BET method is 20-500 [m < ² > / g]. The use ratio of the inorganic fine particles is preferably 0.01 to 5 [wt%] of the toner, and particularly preferably 0.01 to 2.0 [wt%].

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using an average particle diameter of both fine particles of 5 × 10 ⁻² [μm] or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even with stirring and mixing in the developing device to obtain the charge level, the fluidity-imparting agent is not detached from the toner, and good image quality that does not cause firefly and the like can be obtained, and the residual toner is further reduced. Is planned. Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included. The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.

  As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. , Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Manufactured), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footgent F-300 (Neos), and the like.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 [μm] and 3 [μm], polystyrene fine particles 0.5 [μm] and 2 [μm], poly (styrene-acrylonitrile) fine particles 1 [μm], trade name is PB- 200H (manufactured by Kao Corporation), SGP (manufactured by Sokensha), technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) and the like. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Homopolymers or copolymers such as nitrogen-containing compounds such as imidazole and ethyleneimine, or those having a heterocyclic ring thereof,
Polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl Polyoxyethylenes such as phenyl ester and polyoxyethylene nonylphenyl ester, and celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, in order to make the particle size of the dispersion 2 to 20 [μm], a high-speed shearing method is preferable. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 [rpm], preferably 5000 to 20000 [rpm]. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

  5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

As described above, according to the developing device 23 of the present embodiment, the agitator 6 as the developer stirring member is provided with the action shafts 6b and 6c at different distances l and m from the rotation shaft center 6A. In the agitator 7, the operation shafts 7b, 7c, and 7d are provided at different distances n, o, and p from the rotation shaft center 7A. The agitator 8 is provided with operating axes 8b and 8c at different distances q and r from the rotation axis center 8A. Therefore, in comparison with the case where one or a plurality of action shafts are provided at a position equidistant from the center of the rotation axis, the agitators 6, 7, and 8 have rotation axes 6B, 6C, 7B, and 7C of the action shaft. , 7D, 8B, 8C occupy a larger area, and more developer directly receives the stirring action by the action shaft. As a result, the area where the developer tends to stay is reduced, and the developer in the developer container 5 can be stably supplied to the developer supply member.
Further, according to the developing device 23 according to the present embodiment, the rotation trajectories 6B, 7B, and 8B of the action shafts 6b, 7b, and 8b that are closest to the rotation shaft centers 6A, 7A, and 8A of the agitators 6, 7, and 8A. Are configured to pass through the rotation axis centers 6A, 7A, and 8A. Therefore, the toner in the rotation axis centers 6A and 7A where the toner is most likely to stay can be stirred, and the toner can be prevented from staying in the rotation axis centers 6A and 7A.
Further, according to the developing device 23 according to the present embodiment, since the plurality of agitators 6 and 7 are provided, it is possible to improve the toner agitation in the developer accommodating portion 5.
Further, according to the developing device 23 according to the present embodiment, the agitator 6 provided closest to the supply roller 4 is supplied to the outermost periphery of the rotation locus 6C of the action shaft 6c that is the farthest from the rotation shaft center 6A. It arrange | positions in the position from which the space | interval with the roller 4 becomes 1 mm or less. Thereby, the toner supply property to the supply roller 4 can be improved.
The toner used in the developing device 23 has a volume average particle size of 3 to 8 [μm] and a ratio (Dv / Dn) of the volume average particle size (Dv) to the number average particle size (Dn) of 1. It is characterized by being in the range of 00 to 1.40. By using such a toner having a small particle size and a narrow particle size distribution, it is possible to obtain a high-quality image with a uniform toner charge amount distribution and little background fog, and a high transfer rate. On the other hand, since the toner having such a small particle size has a high degree of aggregation, the problem of the present invention is remarkably generated. Therefore, it is effective to use the developing device 23.
The toner shape factor SF-1 is in the range of 100 to 180, and the shape factor SF-2 is in the range of 100 to 180. By using the toner having such a shape, it is possible to improve fluidity, improve the toner supply property, and to obtain a high-quality image without unevenness while keeping the toner layer uniform. Further, it is possible to weaken the adsorption force between the toner and the photosensitive member 1 and the toner adsorption force, and to obtain a high transfer rate. On the other hand, since the problem of the present invention is remarkably generated in such a toner, it is effective to use the developing device 23.
In addition, the toner is obtained by crosslinking a toner material solution in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous medium. It shall be obtained by an extension reaction. This is a toner method capable of controlling the shape and surface morphology, and a toner having a small particle size and a sharp particle size distribution can be easily obtained. Thereby, a high-quality image can be obtained and a high transfer rate can be obtained.
In the process cartridge according to the present embodiment, the photosensitive member 1 and the developing device 23 are integrally formed and configured as a process cartridge that can be attached to and detached from the image forming apparatus main body, thereby improving maintenance. I can plan.
In addition, since the image forming apparatus according to the present embodiment includes the developing device that can perform a good developing operation as described above, it is possible to suppress a rapid change in the image density and to provide a high-quality image. Can be obtained.

1 is a schematic configuration diagram of a color image forming apparatus employing a developing device according to the present embodiment. FIG. 2 is a schematic configuration diagram illustrating a configuration of the developing device. FIG. 3 is an enlarged configuration diagram of a main part for explaining the configuration of the developing device. FIG. 3 is a schematic diagram illustrating a rotation locus of a first agitator of the developing device. (A) is a top view explaining the structure of a 1st agitator, (b) is a schematic diagram explaining the rotation locus | trajectory of a 1st agitator. (A) is a top view explaining the structure of a 2nd agitator, (b) is a schematic diagram explaining the rotation locus | trajectory of a 2nd agitator. (A) is a top view which shows the structure of the agitator which concerns on another embodiment, (b) is a schematic diagram explaining the rotation locus | trajectory of this agitator. FIG. 4 is a schematic diagram showing the shape of a toner for explaining the shape factor SF-1 and the shape factor SF-2. FIG. 10 is a schematic configuration diagram illustrating a configuration of a conventional developing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developing roller 3 Doctor blade 4 Supply roller 5 Developer accommodating part 6 1st agitator 6a Rotating shaft 6A Rotating shaft center 6b, 6c Action shaft 7 2nd agitator 7a Rotating shaft 7A Rotating shaft center 7b, 7c, 7d Action shaft 20 Image forming unit 21 Exposure device 22 Charging device 23 Development device 24 Cleaning device 30 Intermediate transfer belt

Claims (8)

A developer carrying member that carries the developer and conveys it to a portion facing the latent image carrying member, a developer supply member that contacts the developer carrying member while rotating and supplies the developer; and the developer supply In a developing device including a developer accommodating portion that is provided above a member and accommodates a developer, and a developer agitating member that agitates the developer in the developer accommodating portion while rotating.
Said developer stirring member includes a rotary shaft, Ri Do and a plurality of working axes in a position with different distance from the rotation axis center exerts a stirring action to the developer in the developer accommodating portion, said plurality of a developing device rotary locus of the operating shaft in the closest distance from the rotation axis center of the operating shaft is characterized in configuration der Rukoto passing through the rotation axis center. The developing device 請 Motomeko 1,
A developing device comprising a plurality of the developer stirring members. The developing device according to claim 1 or 2 ,
The developer agitating member provided in the vicinity of the developer supply member is positioned at a distance of 1 mm or less between the outermost circumference of the rotation locus of the action shaft at the farthest distance from the rotation axis center and the developer supply member. A developing device, wherein The developing device according to claim 1, 2 or 3 ,
The developer has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) in the range of 1.00 to 1.40. A developing device using a certain toner. The developing device according to claim 1, 2, 3 or 4 ,
The developing device according to claim 1, wherein a toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180 is used as the developer. The developing device according to claim 1, 2, 3, 4 or 5 .
In the developer, a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent is crosslinked in an aqueous medium. And / or an image forming apparatus using a toner obtained by an extension reaction. In the process cartridge that integrally forms the latent image carrier and the developing means and is detachable from the image forming apparatus main body,
The process cartridge, which comprises employing one of the developing apparatus according to claim 2, 3, 4, 5 or 6 as the developing means. An image forming apparatus comprising: a latent image carrier; a latent image forming unit that forms an electrostatic latent image on the latent image carrier; and a developing unit that develops the latent image on the latent image carrier.
Image forming apparatus characterized by employing one of the developing apparatus according to claim 2, 3, 4, 5 or 6 as the developing means.

Images