JP4246582B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a developing device provided with a developer containing toners of a plurality of colors, and an image forming apparatus such as an electrophotographic color copying machine, a color facsimile, a color printer, and a color complex machine provided with the developing device.

  In general, in an electrophotographic color image forming apparatus such as a color copying machine or a color printer, an electrostatic latent image corresponding to image information is formed on an image carrier composed of a photosensitive drum or a photosensitive belt, The image is visualized by the developing device, and then the four color images are superimposed on an intermediate transfer member such as an intermediate transfer belt, and transferred onto transfer paper. In such a two-component developing device used for a color image forming apparatus, a carrier and a toner are mixed as a developer. However, the carrier deteriorates over time, and the image quality deteriorates. Even in a conventional black and white machine, the image quality is deteriorated due to the deterioration of the carrier. However, since the required quality is high in the color image, it is more problematic. In Patent Document 1, in a developing device having a two-component developer composed of toner and a carrier in a developing region, a toner replenishing device that replenishes toner according to toner consumption by a developing operation, and a toner consumption amount in a developing container are disclosed. A developing device that replenishes the carrier from the carrier replenishing device according to the toner consumption detected by the toner consumption detecting means to be detected, discharges the developer in the developing container, and holds the developer at a predetermined value. Are listed.

Japanese Patent Application No. 8-214594

  The deterioration of the carrier of the developing device described above is caused by toner components adhering to the surface of the carrier or wear of the surface layer of the carrier. However, in the current two-component developing device, friction between the carrier and the toner is caused. Since the toner is charged, the carrier is deteriorated and the image quality is lowered. Therefore, a means for preventing the deterioration of the carrier is an issue. Further, when the carrier has deteriorated, the developing device is restored by exchanging the developer as in Patent Document 1. However, when the color is an image forming device, a four-color developing device is provided. Another problem is that it takes maintenance time to replace the color developer. In Patent Document 1, toner density and carrier density are detected. However, in the case of an apparatus capable of forming a color image, there are many devices that can selectively switch between a color image and a black and white image. How to decrease is different.

The present invention, Ri FIG high life of the developing apparatus by suppressing the deterioration of the developer, and an object thereof is to provide an image forming apparatus capable of obtaining a good image.

In order to achieve the above object, according to the first aspect of the present invention, there are provided a plurality of developer storage portions for storing a plurality of color developers including toner and carrier for each color, and a plurality of color developer for each color. In the image forming apparatus , each of the developer storage unit is replenished with a developer corresponding to the color corresponding to the developing device , and the developer color is at least black, yellow, cyan, magenta, A first counter that counts the number of printed sheets by a developing apparatus that uses a developer of yellow, cyan, and magenta, and a second counter that counts the number of printed sheets by a developing apparatus that uses a black developer. When the first counter counts a predetermined number of sheets, a developer that uses yellow, cyan, and magenta is replenished with a developer of yellow, cyan, and magenta, and the second counter Printer is characterized by supplying the black developer to the developing device using a black developer upon counting a predetermined number of sheets.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the image forming apparatus includes a common drive source that drives the developer storage units, and a member that connects the drive source and the developer storage units. Developer supply from each developer storage unit of cyan, magenta to each developer supply unit is performed by driving a drive source .
According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect , the toner has a volume average particle diameter of 3 to 8 μm, a volume average particle diameter (Dv) and a number average particle diameter (Dn). ) (Dv / Dn) is in the range of 1.00 to 1.40.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the toner has 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. It is characterized by being in range.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner comprises at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. It is a toner obtained by crosslinking and / or stretching reaction of a toner material liquid dispersed in an organic solvent in an aqueous medium.
According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner comprises at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. The toner material liquid dispersed in an organic solvent is obtained by crosslinking and / or elongation reaction in an aqueous medium.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the toner has a substantially spherical shape.
According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (provided that r1 ≧ r2 ≧ r3), the ratio of the major axis r1 to the minor axis r2 (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness r3 to the minor axis r2 (r3 / r2) is It is characterized by being in the range of 0.7 to 1.0 .

According to the present invention, the developer replenishment from the developer storage unit to the developer replenishment unit is performed at a predetermined print number interval, so that the deterioration of the developer can be suppressed and the life of the developing device can be extended. And a good image can be maintained.
According to the present invention, developer replenishment from the developer storage unit to the developer replenishment unit is performed by supplying the developer after printing a predetermined number of sheets, so that deterioration of the developer can be suppressed, and the development device can be improved. The lifetime can be increased and a good image can be maintained.
According to the present invention, developer replenishment from the developer storage unit of three colors of yellow, cyan, and magenta to the developer replenishment unit is supplied by the same driving device, so that deterioration of the developer can be suppressed, The life of the developing device can be increased and a good image can be maintained.

According to the present invention, the toner used in the developing unit has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1. Since it is in the range of 00 to 1.40, deterioration of the developer can be suppressed, the life of the developing device can be extended, and a good image can be maintained.
According to the present invention, since the toner used in the developing unit has 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, the deterioration of the developer can be suppressed. In addition, the life of the developing device can be increased and a good image can be maintained.
According to the present invention, the toner used in the developing means 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. Toner obtained by crosslinking and / or elongation reaction in an aqueous medium, or a toner material in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent are dispersed in an organic solvent Since the toner is obtained by crosslinking and / or elongation reaction of the liquid in an aqueous medium, the deterioration of the developer can be suppressed, the life of the developing device can be extended, and a good image can be maintained. Can do.
According to the present invention, since the toner used in the developing unit has a substantially spherical shape, the deterioration of the developer can be suppressed, the life of the developing device can be extended, and a good image can be maintained. Can do.
According to the present invention, the shape of the toner is defined by the major axis r1, the minor axis r2, and the thickness r3 (where r1 ≧ r2 ≧ r3), and the ratio of the major axis r1 to the minor axis r2 ( r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness r3 to the minor axis r2 (r3 / r2) is in the range of 0.7 to 1.0. The lifetime can be increased and a good image can be maintained.

A developing device and an image forming apparatus according to the present invention will be described below with reference to the drawings.
In the image forming apparatus shown in FIG. 1, four photosensitive drums 1Y, 1M, 1C, and 1K as image carriers having a photoconductive layer are arranged in parallel, and each of these photosensitive drums is yellow, cyan, magenta, and black. This is an electrophotographic color image forming apparatus that forms a color image by allocating these four color images and superimposing them. The color image forming apparatus includes image forming units 2, 3, 4, and 5 having photosensitive drums 1Y, 1M, 1C, and 1K that form visible images of yellow, cyan, magenta, and black in the apparatus main body. In this embodiment, a small-diameter drum having a diameter of 40 mm is used for each photosensitive drum. Around each photosensitive drum of each image forming unit, charging devices 6Y, 6M, 6C and 6K as image forming means, exposure device 7, developing devices 8Y, 8M, 8C and 8K, cleaning devices 9Y and 9M, 9C, 9K, etc. are arranged. Each photosensitive drum is in contact with an intermediate transfer belt 10 as an intermediate transfer body between each developing device and each cleaning device.

Next, a color image forming process of the image forming apparatus used in this embodiment will be described. Since each color process is the same, a yellow color image will be described here. At the time of forming a color image, first, in the first image forming unit 2, the surface of the rotating photosensitive drum 1Y is uniformly charged by the charging roller 11Y having an outer diameter of 16 mm constituting the charging device 6Y, and is about −450V. Uniform charging is performed. Thereafter, image exposure 7Y is performed by an exposure device 7 such as a laser optical system, and an electrostatic latent image is formed on the photoconductive layer on the surface of the photosensitive drum 1Y. The electrostatic latent image is developed using a yellow developer from the developing sleeve 12Y provided in the developing device 8Y, and the latent image is visualized as a yellow toner image.

  Next, the development process will be described. The developing device includes a developing container 2Y containing a two-component developer and a developing sleeve 12Y as a developer carrying member, a stirring screw 13Y, and a doctor blade 14Y that forms a toner thin layer on the surface of the developing sleeve. ing. The developing sleeve 12Y is a rotating member having a fixed magnet disposed therein, and is a rotating member having an outer diameter of 20 mm. The developing sleeve 12Y is disposed close to the photosensitive drum 1Y, and is set so that development can be performed while the developer is in contact with the photosensitive drum 1Y. Specifically, the gap between the developing sleeve 12Y and the photosensitive drum 1Y is set between 0.25 and 0.40 mm. The two-component developer used in this embodiment is composed of a negatively charged toner having an average particle diameter of 5 to 6 μm produced by a polymerization method and a magnetic carrier having an average particle diameter of 35 μm. In the initial state, the mixing ratio of the toner and the carrier is set by the toner density control as a weight ratio of 8:92. Further, at the time of development, development is performed by applying −300 V as a development bias to the development sleeve 12Y in the embodiment. A similar process is performed for cyan, magenta, and black color images. When the image formation is monochrome, only the image formation process for black is performed.

  The transfer process will be described. The toner image visualized on the photosensitive member is transferred to the intermediate transfer belt 10 by the first intermediate transfer unit, and then the second, third, and fourth image forming units 3, 4, and 5 are sequentially arranged. The toner images on the photosensitive drum are respectively transferred to the intermediate transfer belt 10, thereby forming a color-superimposed image on the intermediate transfer belt 10. In the case of monochrome, the toner images on the respective photosensitive drums 1K are transferred to the intermediate transfer belt 10 in the order of the fourth image forming unit 6 after being transferred to the intermediate transfer belt 10 by the fourth intermediate transfer unit. Transfer is performed, whereby a monochrome image is formed on the intermediate transfer belt 10.

The toner image formed by superimposing colors on the intermediate transfer belt 10 is transferred to the transfer paper 16 by the secondary transfer belt 15, and then the toner image is thermally fixed to the transfer paper 16 by the fixing device 17. The image is output to a paper discharge unit (not shown ).

  Next, each developing device will be described in detail. Here, the developing device 2Y will be described as a representative, but the other developing devices are denoted by M, C, and K, respectively, and the detailed description thereof is omitted.

As shown in FIG. 2, the developing device 2 </ b> Y includes a developer supply unit 20 that supplies a developer for supply, a developer discharge unit 21 that discharges the developer, and a toner supply unit 23 that supplies toner. . Further, in the vicinity of the developing device 2Y, a developer storage unit 24 storing a developer and a toner storage unit 25 storing toner are provided.

  The developer discharge portion 21 is formed on the end portion 27a side of the stirring member 27 disposed in the developing device 2Y, and is configured to discharge to the outside of the device when the volume of the developer exceeds a certain level. Yes. Reference numeral 28 denotes a conveying screw arranged on the developing sleeve side, and reference numeral 29 denotes a partition wall that separates a developer conveying path conveyed by the stirring member 27 and the conveying screw 28. On both ends of the wall 29, a developer circulation portion is formed. Each developing device and its peripheral portion have the same configuration as that shown in FIG.

First Embodiment In this embodiment, the developer is replenished at intervals of a predetermined number of printed sheets. 2. Description of the Related Art Conventionally, in a developing device configured to replenish a developer, a developer (carrier) is mixed with toner and replenished simultaneously. However, such a configuration has a problem that the amount of replenishment of the carrier is not determined and the toner density varies. Therefore, the developer is replenished with a certain number of sheets, the amount of the carrier in the developing device is stabilized, and the developer is replaced little by little to prevent the deterioration of the developer.

  Specifically, in the case of the present embodiment, the number of A4 size paper is counted with a counter or the like, and when 1000 sheets are printed in terms of A4 size paper, 5 g of developer is supplied thereafter. . The developer replenished at this time was a developer having a carrier to toner weight ratio of 93: 7.

Second Embodiment In this embodiment, a counter for counting the number of printed sheets of yellow, cyan, and magenta and a black counter are provided independently, and control is performed so that the developer is replenished after printing a predetermined number of sheets. It is. In the case of a color machine, development in four colors of yellow, cyan, magenta, and black is performed in the color mode, but in the black mode, development of yellow, cyan, and magenta is not performed, and development of only black is used. . When used in this way, it is necessary to supply developer separately for black, yellow, cyan, and magenta.

  Therefore, in this embodiment, the color counter 30 as a first counter for counting the number of printed sheets when any one of yellow, cyan, and magenta is used, and the number of printed sheets when black printing and color printing are performed. And a black counter 31 as a second counter for counting the number of color counters 30 for each of the developing devices 2Y, 2M, and 2C for yellow, cyan, and magenta at an interval of 1000 sheets. In contrast, 5 g of developer was replenished, and the black counter 31 replenished 5 g of developer to the black developing device 2K at intervals of 1000 sheets.

  Specifically, as shown in FIG. 3, drive motors 34Y, 34M, 34C, and 34K as drive sources for driving the color counter 3, the black counter 31, and the developer storage units 24 corresponding to the developing devices are provided. Connect to control means 33. Then, the drive of each drive motor is controlled by the control means 33 in accordance with the detection results from the color counter 3 and the black counter 31. A predetermined number of prints (here, 1000) is set in the control means 33 in advance.

  This control will be described with reference to the flowchart of FIG. 4. When a print switch (start switch) (not shown) of the image forming apparatus is pressed in step S1 and the apparatus starts printing (printing), each counter is set in step S2. Count the number of prints. In step S3, it is determined whether the number of printed sheets has reached a predetermined number. When the predetermined number is reached, each drive motor is driven in step S4 to replenish the developer.

  In the case of a color machine, development of four colors of yellow, cyan, magenta, and black is performed in the color mode. Therefore, development of yellow, cyan, and magenta is not performed in the black mode, and development of only black is used. Therefore, the developer can be replenished at the same time for yellow, cyan, and magenta developing devices. Therefore, with respect to the supply of the developer from the developer storage unit 24 for yellow, cyan, and magenta, as shown in FIG. 5, when each developer storage unit 24 is driven by a common drive motor 34, a single motor is provided. The device can be downsized rather than being driven by. In this case, the common drive motor and the yellow, cyan, and magenta developer storage unit 24 may be connected and driven by a gear train, a pulley, a belt, and the like.

Next, a toner suitably used for image formation will be described.
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) 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.

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. 6A and 6B are diagrams schematically illustrating the shape of the toner in order to explain 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) (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.

Further, the shape factor SF-2 indicates the unevenness ratio 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 on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100π / 4) Expression (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.

A toner suitably used for image formation according to the present invention comprises 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. A toner obtained by crosslinking and / or elongation reaction in a 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; 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 polyvalent isocyanate 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 deteriorates, 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 Carmin Min BS, 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 salt or compound, tungsten simple substance or compound, fluorine activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. 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 , Phenolic 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 of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as 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, and 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, and 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 particles having an average particle size of 5 × 10-2 μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. .

  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 salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol 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.

  By using a surfactant having a fluoroalkyl group, the effect can be increased 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).

  Cationic surfactants include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids that are right on the fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. Benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (manufactured by Daikin Industries) ), Megafuck F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos).

  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 names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), 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 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 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 Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, 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, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed 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.

The toner according to the present invention has a substantially spherical shape and can be represented by the following shape rule.
FIG. 7 is a diagram schematically showing the shape of the toner of the present invention. In FIG. 6, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present invention has a major axis and a minor axis. Ratio (r2 / r1) (see FIG. 6B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 6C) is 0.7 to 1.0. It is preferable to be in the range of 1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved. Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention. It is sectional drawing which shows the internal structure of a developing device. It is a block diagram which shows the structure of the control system in connection with a developer replenishment. It is a flowchart which shows one form of control in the control system of FIG. It is a block diagram which shows another structure of the control system in connection with a developer replenishment. It is a figure for demonstrating the toner shape count utilized by this invention. It is a figure which shows the shape of the toner utilized by this invention.

Explanation of symbols

1Y, 1M, 1C, 1K Image carrier 2,3,4,5 Image forming unit 2Y, 2M, 2C, 2K Developing device 20 Developer supply unit 24 Developer storage unit
3 0 1st counter 31 2nd counter 34 drive source

Claims (8)

A plurality of developer storage portions each storing a plurality of colors of developer including toner and carrier for each color; and a plurality of developing devices provided for each color of the plurality of colors of developer. In the image forming apparatus in which the developer of the color corresponding to the developing device is replenished from the storage unit ,
A color of the developer is at least black, yellow, cyan, magenta, and a first counter that counts the number of printed sheets by the developing device using the yellow, cyan, magenta developer among the plurality of developing devices ; A second counter for counting the number of printed sheets by the developing device using the black developer,
When the first counter counts a predetermined number of sheets, the yellow, cyan, and magenta developers are supplied to the developing device using yellow, cyan, and magenta, and the second counter counts the predetermined number of sheets. An image forming apparatus, wherein the black developer is replenished to a developing device using the black developer . The image forming apparatus according to claim 1.
A common drive source for driving each developer storage unit, and a member for connecting the drive source and each developer storage unit,
2. An image forming apparatus according to claim 1, wherein the supply of the developer from each of the yellow, cyan, and magenta developer storage units to each of the developer supply units is performed by driving the drive source . The image forming apparatus according to claim 1 or 2,
The toner has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.40. An image forming apparatus . The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus, wherein the toner has 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 . The image forming apparatus according to claim 1,
Before SL toner, at least, a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, a toner material solution dispersed in an organic solvent and a releasing agent, crosslinking and / or extension in an aqueous medium An image forming apparatus comprising a toner obtained by reaction . The image forming apparatus according to any one of claims 1 to 4,
In the toner, 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 extended in an aqueous medium. An image forming apparatus obtained by performing the process . The image forming apparatus according to any one of claims 1 to 6,
The image forming apparatus, wherein the toner has a substantially spherical shape . The image forming apparatus according to claim 1,
The shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and a ratio (r2 / r1) between the major axis r1 and the minor axis r2 is set. An image forming apparatus having a thickness in the range of 0.5 to 1.0 and a ratio (r3 / r2) of the thickness r3 to the minor axis r2 in the range of 0.7 to 1.0 .

Images