JP4933350B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device of an image forming apparatus such as an electrophotographic copying apparatus, a facsimile machine, and a printer, and more particularly to the structure of the developing apparatus.

  Conventionally, four sets of image forming mechanisms having individual image forming functions are built in, and toner images of each color are formed on four image carriers using one-component developers of yellow, magenta, cyan, and black. 2. Description of the Related Art A color image forming apparatus that obtains a color image by sequentially transferring toner images to a transfer material is known. As a developing device used in this image forming apparatus, a nonmagnetic or magnetic developer contained in a container is supplied to a developer carrier by a developer supply member such as foamed urethane, and an elastic member made of a thin metal plate or the like is developed. For example, “Patent Document 1” discloses a developing device that develops an electrostatic latent image formed on an image carrier by bringing the developer on the surface of the agent carrier into pressure contact and making the developer on the developer carrier uniform.

  However, as described above, it is difficult to reduce the size of the developing device in which the developer charging and layer forming portion and the developer storage portion are positioned in parallel. In particular, in a color image forming device having a plurality of developing devices, This was a major obstacle to downsizing the forming apparatus. Further, as one of the measures for reducing the size of the developing device, it is possible to reduce the thickness by providing the developer charging portion and a vertically long developer accommodating portion above the layer forming portion. In the structure in which the supply direction is the direction of gravity, the developer supply amount fluctuates due to a change in the developer storage amount, making it difficult to stably supply the developer, development failure such as fogging due to excessive uncharged developer, Image defects such as density fluctuations occur.

  In recent years, the toner particle size has been reduced with the increase in image quality, and the degree of toner aggregation tends to increase. For this reason, if the device is not used or left for a period of time, the toner in the developing device aggregates due to gravity, and only the toner in the immediate vicinity of the toner supply member and developer carrying member is used when the device is used thereafter. When the toner is used, a so-called hollowing phenomenon occurs, and there is a problem that density reduction and blurring due to poor supply of toner occur. As a method for preventing the toner from agglomerating due to gravity, it is conceivable to constantly stir the toner in the entire range in the developing device. However, it is difficult to move the toner up and down with a vertically long developing device, and an unnecessary load is applied to the toner. Imparting toner promotes the deterioration of the toner or, depending on the direction of stirring, deteriorates the toner circulation in the vicinity of the toner supply member.

  In order to solve this problem, the vertically long developing device is divided into upper and lower parts, the toner amount on the lower side is detected, and the rotation of the toner replenishing member is controlled based on this, so that the toner pressure is hardly applied in the vicinity of the toner supplying member. A developing device having the above configuration is disclosed in, for example, “Patent Document 2”. Further, for example, “Patent Document 3” discloses a developing device including a toner load reducing unit that reduces a load applied to a developer carrier, a doctor blade, and a toner supply member.

Japanese Patent No. 3320954 JP 2003-5487 A JP 2001-194 483 A

  However, in the technique disclosed in “Patent Document 2”, it is necessary to provide four sets of members such as a detector for detecting the amount of toner and an electromagnetic clutch for controlling the rotation of the toner replenishing member corresponding to each developing device. There is a problem that the apparatus becomes complicated and the cost increases.

  Further, in the technique disclosed in “Patent Document 3”, since the load is directly applied to the toner load reducing means, the thermal characteristics are lowered due to the small particle diameter and energy saving employed for high image quality. The above-mentioned toner is not effective, and there is a problem in that the above-mentioned troubles due to a decrease in fluidity cannot be avoided in a high temperature and high humidity environment.

  The present invention solves the above-described problems, and is a developing device capable of downsizing with a vertically long developer container provided above the charging and layer forming portion of the developer. An object of the present invention is to provide a developing device capable of performing a stable developer replenishment and enabling a good developing operation.

According to the first aspect of the present invention, there is provided a developer carrier, a developer supply member that supplies the developer to the developer carrier, and a rotatable member that is disposed above the developer supply member and stirs the developer therein. In the developing device having a developer containing member having a stirrer, the developer containing portion has a discharge port for dropping and discharging the developer, and the discharge port is located at a position lower than the lowest point of the rotation track of the stirrer. The stirrer is provided so as to be shifted in a direction away from the developer carrier, and has a circular arc shape at the downstream side in the rotation direction at the tip thereof, while the stirrer is formed in a shape that reduces the developer conveying force. Features.

According to a second aspect of the present invention, there is provided a developer carrier, a developer supply member that supplies the developer to the developer carrier, and a rotatable member that is disposed above the developer supply member and stirs the developer therein. In the developing device having a developer containing member having a stirrer, the developer containing portion has a discharge port for dropping and discharging the developer, and the discharge port is located at a position lower than the lowest point of the rotation track of the stirrer. The stirrer is formed in a shape that reduces the developer conveying force, and has a wedge shape on the downstream side in the rotational direction of the tip. Features.

According to a third aspect of the present invention, in the developing device according to the first or second aspect, the discharge port is further provided so as to be shifted downstream in the rotation direction of the stirrer .

According to a fourth aspect of the present invention, in the developing device according to any one of the first to third aspects, the wall surface having the discharge port of the developer containing portion is inclined so that the developer inside falls. It is characterized by.

According to a fifth aspect of the present invention, in the developing device according to any one of the first to fourth aspects, the developer accommodating portion is further detachable .

A sixth aspect of the present invention is a process cartridge having the developing device according to any one of the first to fifth aspects.

A seventh aspect of the invention is an image forming apparatus having the developing device according to any one of the first to fifth aspects.

An eighth aspect of the invention is an image forming apparatus having the process cartridge of the sixth aspect.

According to a ninth aspect of the present invention, in the image forming apparatus of the seventh or eighth aspect , the volume average particle diameter (Dv) is 3 to 8 μm, and the ratio of the volume average particle diameter to the number average particle diameter (Dn) ( A developer having a Dv / Dn) of 1.00 to 1.40 is used .

According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the seventh to ninth aspects , a developer having a shape factor SF1 of 100 to 180 and a shape factor SF2 of 100 to 180 is used. It is characterized by that.

According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the seventh to tenth aspects, at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. A developer obtained by cross-linking and / or extending a toner material liquid in which an organic solvent is dispersed in an organic solvent in an aqueous medium is used.

  According to the present invention, toner can be replenished so that no pressure is applied to the toner. Therefore, the occurrence of voiding can be prevented to prevent density reduction and blurring, and stable toner replenishment can be achieved. A developing device capable of performing a good developing operation can be provided.

  FIG. 1 shows an image forming apparatus employing the first embodiment of the present invention. In FIG. 1, an image forming apparatus 1 has a photosensitive drum 2 inside the apparatus main body, and a charging roller 3 for charging the surface of the photosensitive drum 2 around the photosensitive drum 2 and a uniformly charged photosensitive drum. An exposure device 4 that forms an electrostatic latent image with a laser beam on the surface 2; a developing device 6 that supplies charged toner to the surface of the photosensitive drum 2 to develop the electrostatic latent image into a toner image; and a transfer belt 5a. A transfer device 5 for transferring the toner image formed on the photosensitive drum 2 to the recording paper 9, a cleaning device 7 for removing residual toner remaining on the photosensitive drum 2 after the toner image transfer, and the photosensitive drum 2 A neutralizing device 8 for removing the residual potential is provided.

  In the above configuration, the photosensitive drum 2 whose surface is uniformly charged by the charging roller 3 forms an electrostatic latent image by the exposure device 4, and is developed by the developing device 6 to form a toner image on the surface. . This toner image is transferred by the transfer device 5 to the recording paper 9 fed through the registration roller pair 11 from the paper feeding device 10 provided at the lower part of the apparatus main body, and the recording paper 9 on which the toner image is transferred is fixed. After the toner image is fixed by being sent to the apparatus 12, it is sent to a subsequent process by the paper discharge roller pair 13. After the residual toner is removed by the cleaning device 7, the photosensitive drum 2 is discharged by the charge removing device 8 and used for the next image forming process. In the transfer device 5, the toner remaining on the transfer belt 5a is cleaned by the belt cleaning device 5b.

  FIG. 2 is a schematic view of the developing device 6 which is a characteristic part of the present invention. The developing device 6 includes a developing roller 15 as a developer carrying member in a housing 14, a supply roller 16 as a developer supply member that shares toner as a developer with the developing roller 15, an agitator 17 that stirs the toner, a development A doctor blade 20 for thinning the toner on the roller 15, a developer accommodating portion 18 for accommodating the toner provided on the upper portion of the housing 14, and the like. A stirrer 19 for stirring the stored toner is rotatably provided inside the developer storage unit 18, and the developer storage unit 18 is provided on the wall surface 14 a of the housing 14 that constitutes the developer storage unit 18. A discharge port 21 through which the toner inside is dropped and discharged is provided.

  Here, in the developing device 6, the toner supplied from the developer container 18 flows along the rotation direction of each rotating body as shown in FIG. 3. The toner scraped off by the doctor blade 20 flows downstream by being pushed out from the upstream side although there is no rotating body in the vicinity thereof. The toner supplied from the developer accommodating portion 18 has such a flow, and the toner is likely to agglomerate particularly in the nip portion of the doctor blade 20, so that the pressure is applied to the toner from above. It is not preferable. Therefore, in the present invention, the discharge port 21 is arranged at a position shifted from the lowest point position of the rotation locus A of the stirrer 19 so that the toner supplied from the developer accommodating portion 18 does not apply pressure downward. Yes. Further, as shown in FIG. 4, since the nip portion of the doctor blade 20 wants to release at least the pressure, the position of the discharge port 21 is the direction away from the developing roller 15 and the doctor blade 20, and the rotation locus A of the stirrer 19 is the most. It is arranged on the opposite side across the lower point position.

  With the above-described configuration, it is possible to avoid toner discharge near the nip portion of the doctor blade 20 where pressure is not most applied and to replenish the toner without applying pressure to the toner. Further, it is possible to prevent the occurrence of fading and to perform a good developing operation by performing stable toner replenishment.

  In the above-described configuration, the rotation direction of the stirring bar 19 is not mentioned. However, when the stirring bar 19 is rotated clockwise as shown in FIG. It is positioned upstream of the lower point position in the rotation direction of the stirrer 19, and pressure acts on the toner that is dropped and discharged from the discharge port 21. Therefore, by rotating the stirring bar 19 counterclockwise as shown in FIG. 6, the position of the discharge port 21 is located downstream of the lowest point position of the rotation locus A of the stirring bar 19 in the rotation direction of the stirring bar 19. Therefore, the toner can be configured such that no pressure acts on the toner, and a satisfactory developing operation can be performed by stably supplying the toner.

  FIG. 7 shows a second embodiment of the present invention. The second embodiment is different from the first embodiment only in that a stirrer 22 is used instead of the plate-like stirrer 19, and the other configurations are the same. The stirrer 22 has a tip member 22a having a cylindrical shape at both ends thereof, and each tip member 22a is connected to the center of rotation by a plurality of ribs 22b.

  According to the above-described configuration, it is possible to reduce the conveying force generated in the tangential direction of rotation as compared with the case where the stirrer 19 is used, and to supply toner stably by adopting a configuration in which no pressure is applied to the toner. Thus, a good developing operation can be performed.

  In the second embodiment, the stirrer 22 including the tip member 22a having a circular shape is used. However, instead of the stirrer 22, an arc shape is formed on the downstream side in the rotation direction as shown in FIG. The stirrer 23 having the tip member 23a having the tip member 24a or the stirrer 24 having the tip member 24a having a wedge shape on the downstream side in the rotation direction as shown in FIG. 8B may be used. The shape of the tip of the stirrer is not limited to this, and any shape may be used as long as the conveying force generated in the tangential direction of rotation can be reduced.

  FIG. 9 shows a third embodiment of the present invention. The third embodiment is different from the second embodiment only in that a wall surface 14b and a discharge port 25 are used instead of the wall surface 14a and the discharge port 21 of the housing 14, and the other configurations are the same. is there. The wall surface 14b is formed so as to be inclined in the direction in which the developer accommodated in the developer accommodating portion 18 falls, and an end portion of the wall surface 14b is separated from the housing 14 and a discharge port 25 is formed.

  According to the above-described configuration, it is possible to prevent toner from staying in the developer accommodating portion 18, and to perform a good developing operation by performing stable toner replenishment, and in the developer accommodating portion 18. The toner can be consumed without waste.

  FIG. 10 shows a fourth embodiment of the present invention. In the fourth embodiment, the photosensitive drum 2, the charging roller 3, the developing device 6, the cleaning device 7, and the charge removal device 8 shown in FIG. 1 are integrally formed as a process cartridge 26, and the process cartridge 26 is an image. The forming apparatus 1 is configured to be detachable from the apparatus main body.

  According to the above-described configuration, toner aggregation in the developing device 6 is suppressed, and the toner layer on the image carrier 2 can be stabilized. Further, by integrating the members around the photosensitive drum 2, the image forming apparatus 1 can be reduced in size, and the process cartridge 26 can be attached to and detached from the apparatus main body of the image forming apparatus 1. Or the workability | operativity at the time of trouble occurrence can be improved significantly.

  FIG. 11 shows an image forming apparatus 27 adopting the fifth embodiment of the present invention. The image forming apparatus 27 has four process cartridges 26 containing toners of different colors (yellow, magenta, cyan, black) in parallel inside the apparatus main body 28, and above each photosensitive drum. 2 is provided with an intermediate transfer belt 30 to which a toner image formed on each photosensitive drum 2 is transferred. The intermediate transfer belt 30 is stretched between two rollers 31 and 32, and the toner on each photosensitive drum 2 is positioned on the inner surface side of the intermediate transfer belt 30 and facing each photosensitive drum 2. A primary transfer roller (not shown) for transferring the image to the intermediate transfer belt 30 is provided. In addition, a secondary transfer roller 33 is disposed at a position facing the roller 32 via the intermediate transfer belt 30 to transfer the toner image that has been primarily transferred so as to be superimposed on the intermediate transfer belt 30 onto the paper P in a lump. It is installed.

  Below the intermediate transfer belt 30, a paper feed unit 34 for separating and feeding the paper P is disposed. The sheet P fed from the sheet feeding unit 34 is transferred with a full color image at the nip portion between the roller 32 and the secondary transfer roller 33, and then the image is transferred to the fixing device 34 disposed downstream of the sheet conveying direction. Are discharged and discharged onto a discharge tray 36 provided on the upper portion of the apparatus main body 28 by a discharge roller pair 35.

  With the above-described configuration, the image forming apparatus 27 can be reduced in size and workability can be improved, and a full color image can be easily obtained.

  In each of the above embodiments, the developing device 6 includes the developer accommodating portion 18 that is integrally formed with the housing 14. However, the developer accommodating portion that is detachable from the developing device 6 instead of the developer accommodating portion 18. It is good also as a structure using. With this configuration, even if the toner is used up, it is only necessary to replace the toner cartridge, the replacement period of the developing device itself can be extended, and the running cost can be reduced.

  Next, the toner applicable to the present invention will be described. Usually, in order to reproduce minute dots of 600 dpi or more, the toner preferably has a weight average particle diameter (D4) of 3 to 8 μm. The toner in this range has excellent toner reproducibility because it has toner particles having a sufficiently small particle size with respect to minute latent image dots. When the weight average particle diameter is less than 3 μm, a phenomenon such as a decrease in transfer efficiency and a decrease in blade cleaning property is likely to occur. When the weight average particle diameter exceeds 8 μm, it is difficult to suppress scattering of characters and lines.

  The ratio (D4 / D1) of the weight average particle diameter to the number average particle diameter (D1) is preferably in the range of 1.00 to 1.40. The closer the (D4 / D1) is to 1.00, the sharper the particle size distribution is. The toner having such a small particle size and a narrow particle size distribution has a uniform charge amount distribution and less rash on the background. A high-quality image can be obtained, and the transfer rate can be increased in the electrostatic transfer system.

  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, as the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is dispersed for 1 to 3 minutes with an ultrasonic disperser, and the weight and number of toner particles or toner are measured using the 100 μm aperture as the aperture by the measuring device. And calculate. The weight average particle diameter and number average particle diameter of the toner can be obtained from the obtained distribution.

  As a channel, it is less than 2.00 to less than 2.52 μm, less than 2.52 to 3.17 μm, less than 3.17 to 4.00 μm, less than 4.00 to 5.04 μm, less than 5.04 to 6.35 μm, 6 .35 to less than 8.00 μm, less than 8.00 to 10.08 μm, less than 10.08 to 12.70 μm, less than 12.70 to 16.00 μm, less than 16.00 to less than 20.20 μm, 20.20 to 25.25. Using 13 channels of less than 40 μm, 25.40 to less than 32.00 μm, and less than 32.00 to less than 40.30 μm, particles having a particle size of 2.00 μm to less than 40.30 μm are targeted.

The shape factor SF1 of the toner is preferably in the range of 100 to 180, and the shape factor SF2 is preferably in the range of 100 to 180. The shape factor SF1 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.
SF1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF1 is 100, the shape of the toner is a true sphere, and becomes larger as the value of SF1 increases.

The shape factor SF2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). This is a value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF2 = {(PERI) ² / AREA} × (100 / 4π) (2)
When the SF2 value is 100, unevenness does not exist on the toner surface, and as the SF2 value 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 (LUSEX3: manufactured by Nireco), and analyzing and calculating it. did. When the shape of the toner is close to a sphere, the contact state between the toner and the toner or the toner and the image carrier becomes point contact, so that the adsorbing force between the toners is weakened and the fluidity is increased. The attraction force becomes weak and the transfer rate increases. If either of the shape factors SF1 and SF2 exceeds 180, the transfer rate is lowered, which is not preferable.

  The toner suitably used in the image forming apparatus 1 is a toner-based liquid in which an aqueous solvent is used 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. It is a toner obtained by crosslinking and / or elongation reaction therein. Hereinafter, constituent materials and manufacturing methods of the toner will be described.

  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) is preferable. . Dihydric alcohol (DIO) includes 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.) adducts of the alicyclic diols, bisphenol Alkylene oxide Le ethers (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts. Among these, 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. As trihydric or higher polyhydric alcohol (TO), trihydric or higher polyhydric aliphatic alcohol (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 polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and a mixture of (DIC) and a small amount of (TC) Is 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) , Naphthalenedicarboxylic acid, etc.). 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 polyvalent carboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polycarboxylic 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, as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH], preferably 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  The polycondensation reaction between the polyhydric alcohol (PO) and the polycarboxylic acid (PC) is performed at 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxy titanate or dibutyltin oxide 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 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 the electric resistance, particularly the environmental fluctuation. The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. If the weight average molecular weight is less than 10,000, the offset resistance deteriorates, which is not preferable. If the weight average molecular weight exceeds 400,000, the low temperature fixability deteriorates, which is not preferable.

  The polyester preferably contains a urea-modified polyester in addition to the unmodified polyester obtained by the above polycondensation reaction. 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, This is obtained by crosslinking and / or extending the molecular chain by the reaction of this 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, the above polyisocyanates with phenol derivatives or oximes, Those blocked with caprolactam or the like and combinations of two or more of these may be mentioned.

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

  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%. It is. If it is less than 0.5 wt%, the hot offset resistance is deteriorated and disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability, and if it exceeds 40 wt%, the low-temperature fixability is deteriorated. 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 2.5 on average. It is a piece. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance deteriorates.

  As amines (B) to be reacted with the polyester prepolymer (A), divalent amine compounds (B1), trivalent or higher polyvalent amine compounds (B2), amino alcohols (B3), amino mercaptans (B4), amino acids (B5), and those obtained by blocking the amino groups of B1 to B5B (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.) and 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 B1 to B5 amino group blocked (B6) 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 the amines (B) is the equivalent ratio [NCO] / [NHx] of the isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and the amino groups [NHx] in the amines (B). However, it is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is less than 1/2 or more than 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 as well as 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, 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 polycarboxylic acid (PC) are heated to 150-280 ° C in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc. A polyester having a hydroxyl group is obtained. Subsequently, polyisocyanate (PIC) is reacted with this in an atmosphere of 40 to 140 ° C. to obtain a polyester prepolymer (A) having an isocyanate group. Furthermore, this polyester prepolymer (A) is reacted with amines (B) in an atmosphere of 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting the polyvalent isocyanate (PIC) and reacting the polyester prepolymer (A) and the amines (B), a solvent can be used as necessary. Solvents that can be used at this time include aromatic solvents (toluene, xylene, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, etc.), amides (dimethylformamide, dimethylacetamide, etc.) And those inert to isocyanates (PIC) such as ethers (tetrahydrofuran, etc.).

  In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), the molecular weight of the urea-modified polyester obtained using a reaction terminator can be adjusted as necessary. 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, more preferably 30,000 to 1,000,000. When the weight average molecular weight is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of 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, and more preferably 2000-8000. When the number average molecular weight exceeds 20,000, low-temperature fixability and glossiness when used in a full-color image forming apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the glossiness when used in a full-color image forming apparatus 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 improving 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, 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 disadvantageous in terms of achieving 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. When the glass transition point is less than 45 ° C., the heat resistance of the toner deteriorates, and when it exceeds 65 ° C., the low-temperature fixability becomes insufficient. In addition, since the urea-modified polyester is easily 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.

  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 manero (NCG), Vulcan fast yellow (5G, R), tartra gin 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, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast The -Lett G, brilliant fast scarlet, brilliant carmine BS, permanent red (F2R, F4R, FRL, FRLL, F4RH) fast scarlet VD, velcan fast rubin B, brilliant scarlet G, risor 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, Thioindigo Red B, Thio Indigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion 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, Phthalocyanine 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. The binder resin to be kneaded together with the production of the masterbatch or the masterbatch includes polystyrene, poly-p-chlorostyrene, polyvinyltoluene and other styrene and its substituted polymers, copolymers of these with vinyl compounds, poly Methyl 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, aliphatic Or an alicyclic hydrocarbon resin, an aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. are mentioned, These can be used individually or in mixture.

  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-condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (manufactured by Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, azo Pigment, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, materials that control the negative polarity of the toner are particularly preferably used.

  The amount of the charge control agent used is determined by the toner manufacturing method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, but is not uniquely limited. The amount is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. More preferably, the range is 0.2 to 5 parts by weight. When the amount exceeds 10 parts by weight, the chargeability of the toner becomes too high, reducing the effect of the charge control agent, increasing the electrostatic attraction force with the developing roller, leading to a decrease in developer fluidity and a decrease in image density. .

  As the 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 binder resin and the dispersion between the fixing roller and the toner interface. Effective against high temperature offset without applying a release agent such as oil. Examples of such wax components include waxes and waxes such as plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, and mineral waxes such as ozokerite and cercin. And petroleum waxes such as paraffin, microcrystalline, and 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, aliphatic amides such as 12-hydroxystearic amide, stearic amide, phthalic anhydride imide, chlorinated hydrocarbon, and poly-n-stearyl methacrylate, poly-n-lauryl which are low molecular weight crystalline polymer resins A crystalline polymer having a long alkyl group in the side chain, such as a homopolymer or copolymer of polyacrylate such as 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 masterbatch and the binder resin, and may be added when dissolved or dispersed in an organic solvent.

Inorganic fine particles are preferably used as external additives for assisting the fluidity, developability and chargeability of the toner particles. Preferably the primary particle diameter of the inorganic fine particles is 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. 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, and diatomaceous earth. , Chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like. 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 particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved, so that a desired charge level is obtained. Even when stirring and mixing inside the developing device is performed to obtain a good quality image that does not generate so-called fireflies without releasing the fluidity imparting agent from the toner, and further reduces the residual toner. Can be planned.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rising characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, the side effect is affected. It can be considered large. However, when the addition 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 images. A stable quality image can be obtained even if it is formed.

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not restricted to this.
First, a toner material liquid 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 etc. can be used individually or in combination of 2 or more types. 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 amount of the organic solvent used is usually 0 to 300 parts by weight, preferably 0 to 100 parts by weight, and more preferably 25 to 70 parts by weight with respect to 100 parts by weight of the polyester prepolymer.

  Next, 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, and contains 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. 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 it 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, and if it exceeds 2000 parts by weight, it is not economical.

  In order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant or 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 alcohol derivatives Nonionic surfactants such as alanine, dodecyl di (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine That.

  Moreover, the effect can be raised in a very small amount by using a surfactant having a fluoroalkyl group. 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 thereof, 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) par Fluorooctanesulfonamide, 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.), MegaFuck 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).

  Cationic surfactants include aliphatic primary, secondary or secondary amine acids having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, and benzas. Examples thereof include luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, and the like. Kogyo Co., Ltd.), MegaFac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), 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, etc. are mentioned, and the trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Examples include technopolymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Soken), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.). 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-described resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymeric protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride and other acids or hydroxyl group-containing (meth) acrylic monomers 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-hydroxypropyl , Acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate 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, etc., 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 imidazole , Homopolymers or copolymers such as those containing nitrogen-containing compounds such as ethyleneimine, or heterocycles thereof, polyoxyethylene, polyoxypropylene Polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known methods such as a low-speed shearing method, a friction method, a high-pressure jet method, and an ultrasonic method can be applied. Among these, a high-speed shearing method is preferable because the particle size of the dispersion is 2 to 20 μm. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 3000 r. p. m, preferably 5000-20000 r. p. m. 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 at the time of dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

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

  After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant) to obtain toner base particles that are not washed and dried. In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, strong stirring is applied in a certain temperature range, and then solvent removal is performed to prepare spindle-shaped toner base particles. When a dispersion stabilizer that is soluble in an acid or alkali such as calcium phosphate is used, the calcium phosphate salt is dissolved from the toner base particles by, for example, washing with water after dissolving the calcium phosphate salt with an acid such as hydrochloric acid. Can be removed. In addition, it can also be removed by methods such as enzymatic degradation.

  The toner is obtained by implanting a charge control agent into the toner base particles obtained by the above-mentioned steps and then externally adding inorganic fine particles such as silica fine particles and titanium oxide fine particles. 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. Thus, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by applying strong agitation in the process of removing the organic solvent, the toner shape can be controlled between the true sphere shape and the rugby ball shape, and the surface morphology is also controlled between the smooth and umeboshi shape. Is possible.

  In each of the above-described embodiments, an example in which an electrophotographic copying apparatus is used as the image forming apparatus 1 is shown. However, the image forming apparatus to which the present invention can be applied is not limited to this, and the present invention is not limited to this. Of course, the present invention can be applied to other image forming apparatuses.

1 is a schematic front view of a main part of an image forming apparatus employing a first embodiment of the present invention. 1 is a schematic diagram of a developing device adopting a first embodiment of the present invention. FIG. 7 is a schematic diagram illustrating a developer flow in the developing device. It is the schematic explaining the developer accommodating part used for the 1st Embodiment of this invention. It is the schematic explaining the flow of the developer accompanying rotation of the stirring bar in the 1st Embodiment of this invention. It is the schematic explaining the flow of the developer accompanying rotation of the stirring bar in the 1st Embodiment of this invention. It is the schematic of the developing device used for the 2nd Embodiment of this invention. It is the schematic which shows the shape of the stirring bar used for the modification of the 2nd Embodiment of this invention. It is the schematic of the image development apparatus used for the 3rd Embodiment of this invention. It is the schematic of the process cartridge used for the 4th Embodiment of this invention. It is a principal part schematic front view of the full-color image forming apparatus which employ | adopted the 5th Embodiment of this invention.

Explanation of symbols

1, 27 Image forming device 6 Developing device 14b Wall surface 15 Developer carrier (developing roller)
16 Developer supply member (supply roller)
18 Developer container 19, 22, 23 Stirrer 21, 25 Discharge port 26 Process cartridge

Claims (11)

A developer container having a developer carrier, a developer supply member that supplies the developer to the developer carrier, and a rotatable stirrer that is disposed above the developer supply member and stirs the developer therein. In a developing device having a member,
The developer accommodating portion has a discharge port for dropping and discharging the developer, and the discharge port is provided so as to be shifted in a direction away from the developer carrier from the lowest point position of the rotation path of the stirrer . 2. The developing device according to claim 1, wherein the stirrer is formed in a shape in which the developer conveying force is reduced and has an arc shape on the downstream side in the rotation direction of the tip . A developer container having a developer carrier, a developer supply member that supplies the developer to the developer carrier, and a rotatable stirrer that is disposed above the developer supply member and stirs the developer therein. In a developing device having a member,
The developer accommodating portion has a discharge port for dropping and discharging the developer, and the discharge port is provided so as to be shifted in a direction away from the developer carrier from the lowest point position of the rotation path of the stirrer. The developing device according to claim 1, wherein the stirrer is formed in a shape in which the developer conveying force is reduced, and has a wedge shape on the downstream side in the rotational direction of the tip . The developing device according to claim 1 or 2,
The developing device according to claim 1, wherein the discharge port is provided so as to be shifted downstream in the rotation direction of the stirrer . The developing device according to any one of claims 1 to 3 ,
The developing device according to claim 1, wherein a wall surface having the discharge port of the developer accommodating portion is inclined in a direction in which the developer inside falls . In the developing device according to any one of claims 1 to 4 ,
The developing device, wherein the developer accommodating portion is detachable . 6. A process cartridge comprising the developing device according to claim 1. An image forming apparatus comprising the developing device according to claim 1 . An image forming apparatus comprising the process cartridge according to claim 6 . The image forming apparatus according to claim 7 or 8 ,
A developer having a volume average particle diameter (Dv) of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter to the number average particle diameter (Dn) of 1.00 to 1.40 is used. An image forming apparatus. The image forming apparatus according to any one of claims 7 to 9 ,
An image forming apparatus using a developer having a shape factor SF1 of 100 to 180 and a shape factor SF2 of 100 to 180 . The image forming apparatus according to any one of claims 7 to 10 ,
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 and / or elongated in an aqueous medium. An image forming apparatus using a developer .

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