JP2005266270A - Development device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent density unevenness of a toner image, by preventing the degradation in an amount of pumping-up of a developer with lapse of time, while ensuring the cleaning properties. <P>SOLUTION: The developing device has a roller-shaped developer carrier 14b, which is arranged to face an an image carrier 12 apart a developing gap "G" and carries and conveys a two-component developer composed of a magnetic carrier and toner. A plurality of grooves 20, extending in parallel with the central line of the developer carrier 14b, are formed on the surface of the developer carrier 14b. Inorganic particulates of 30 to 160 nm in average grain size are incorporated into the toner. The cleaning properties from the image carrier 12 are improved by the effect of the inorganic particulates incorporated into the toner. In addition, the degradation in the amount of the pumping-up of the two-component developer with the lapse of time can be suppressed by the grooves 20 formed on the developer carrier 14b, even if the toner containing the inorganic particulates are used and the occurrence of the density unevenness of the toner image can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  2. Description of the Related Art Conventionally, a developing device that forms a toner image by supplying toner to the surface of a photoconductor as an image carrier on which an electrostatic latent image is formed is transferred to a sheet-like recording medium such as paper. An image forming apparatus configured to do this is known.

  Examples of the developing device include those shown in FIGS. 9 and 10. FIG. 9 is a schematic view of the developing roller of the developing device. The developing roller 100 includes a cylindrical developing sleeve 101 and flanges 102 fixed to both ends thereof. The outer peripheral surface of the developing sleeve 101 is roughened by sandblasting so that the developer does not slip and stay on the developing sleeve 101 even when the developing roller 100 rotates at high speed. Further, a magnet 103 as a magnetic field generating means is provided inside the developing sleeve 101, and the developing roller 100 is supported so as to be rotatable around a center line. Further, a regulating blade 104 extending in the center line direction of the developing roller 100 is provided around the developing sleeve 101 with a predetermined distance from the developing sleeve 101. The regulating blade 104 regulates the thickness of the developer that adheres to the outer peripheral surface of the developing roller 100.

  FIG. 10 is a schematic diagram of the developing device. In this developing device, the developing roller 100 shown in FIG. 9 is disposed at a position facing the photoconductor 105 with a gap (hereinafter referred to as a developing gap). The developing device contains a two-component developer composed of a magnetic carrier and toner. The developing roller 100 is rotationally driven in the direction of the arrow by a driving unit (not shown). The magnet 103 inside the developing roller 100 emits magnetic lines of force as shown by dotted lines in the figure. In the developing device, a stirring roller 106 is disposed adjacent to the developing roller 100. The stirring roller 106 is also rotationally driven by drive means (not shown) in the direction of the arrow. Recent image forming apparatuses tend to narrow the developing gap between the photoconductor 105 and the developing roller 100 in order to obtain a highly accurate image.

  In addition, the developer toner contains a wax, and oilless toner that does not require oil during fixing is becoming mainstream. Further, the dot reproducibility is improved by making the toner small in particle size and close to a spherical shape (for example, see Patent Document 1).

  After the electrostatic latent image formed on the photoconductor 105 is developed and transferred from the photoconductor 105 to a paper or sheet-like recording medium, the toner remaining on the photoconductor 105 is deposited on the outer peripheral surface of the photoconductor 105. It is cleaned by a cleaning device provided with a blade that contacts (not shown).

JP-A-5-224456

  However, since the toner has a small particle size and close to a spherical shape, the contact with the photoconductor becomes difficult to catch on the blade scraping off the remaining toner, resulting in poor cleaning such as the toner slipping through the blade. I know that will let you. When a cleaning failure occurs, it coincides with a portion that cannot be scraped off, and a band-like streak (abnormal image) is generated.

  In order to improve the above-mentioned problem, Patent Document 1 contains silica fine particles obtained by a substantially spherical deflagration method to improve the cleaning performance from the photoreceptor.

  However, when using the above silica, silica contained in the toner is deposited in the developing device in time, the amount of the developer is adjusted by the regulating blade (hereinafter, referred to as the amount of the pumped up.) Sometimes resulting in decreased. As a result, the desired developing ability cannot be obtained, and the image density is lowered, and as a result, an abnormal image such as roughness is generated. Further, if the toner density is increased in order to increase the image density, toner scattering occurs and the inside of the image forming apparatus is significantly soiled.

  An object of the present invention is to prevent a decrease in the amount of pumping with time and to prevent unevenness in the density of a toner image while ensuring cleanability from a photoreceptor.

  According to the first aspect of the present invention, there is provided a two-component development comprising a roller-shaped developer carrying member, which is opposed to the image carrying member with a development gap “G” and is rotatable about a center line, a magnetic carrier and toner. comprising a material, said developing device develops the electrostatic latent image formed on the image bearing member with toner of a two-component developer to be carried on the developer carrying member conveying to form a toner image The toner contains an electrostatic charge developing base toner containing at least a binder resin and a colorant and inorganic fine particles having an average particle size of 30 to 160 nm, and the developer is provided on the surface of the developer carrying member. A plurality of grooves extending in parallel with the center line of the carrier are formed.

  According to a second aspect of the present invention, in the developing device according to the first aspect, the depth of the groove is 0.05 to 0.15 mm from the surface of the developer carrying member, and the deviation of the groove depth is 30% or less. It is characterized by being.

  According to a third aspect of the present invention, in the developing device according to the first or second aspect, the development gap “G” is 0.1 to 0.4 mm.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the magnetic carrier has a particle size of 20 to 50 μm.

  Invention of claim 5, wherein, in the developing apparatus according to claim 4, wherein the magnetic carrier is a resin-coated film is coated on the core material of the magnetic substance, the resin-coated film to crosslink the thermoplastic resin and melamine resins characterized in that it contains a resin component and a charge controlling agent.

  According to a sixth aspect of the present invention, in the developing device according to any one of the first to fifth aspects, the toner includes at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. A toner material liquid in which is dispersed in an organic solvent is obtained by at least one of a crosslinking reaction and an extension reaction in an aqueous medium.

  Invention of claim 7, wherein, in the developing device according to any one of claims 1 to 6, wherein the toner has a volume average particle size of 3 to 8 [mu] m, a volume average particle diameter (Dv) to the number average particle diameter (Dn ) (Dv / Dn) is 1.00 to 1.40.

  Invention of claim 8, wherein, in the developing device according to any one of claims 1 to 7, wherein the toner has a shape factor SF-1 of 100-180 and a shape factor SF-2 is 100 to 180 Features.

  When invention of claim 9, wherein, in the developing device according to any one of claims 1 to 8, wherein the toner is substantially spherical, the shape has the major axis r1, a minor axis r2, and a thickness of r3 ( Where r1 ≧ r2 ≧ r3), the ratio of the major axis r1 to the minor axis r2 (r2 / r1) is 0.5 to 1.0, and the ratio of the thickness r3 to the minor axis r2 (r3 / r2). ) Is 0.7 to 1.0.

  According to a tenth aspect of the present invention, there is provided a process cartridge according to a tenth aspect of the present invention, an image carrier having a toner image formed on an outer peripheral surface thereof, a cartridge case for rotatably holding the image carrier, and a cartridge case provided in the cartridge case. And a developing device according to any one of claims 1 to 9, disposed opposite to the outer peripheral surface of the body.

  An image forming apparatus according to an eleventh aspect of the present invention is an image carrier on which a toner image is formed on an outer peripheral surface, a charging device that uniformly charges the outer peripheral surface of the image carrier, and the uniformly charged device. an optical writing device for writing an electrostatic latent image on the outer peripheral surface of the image bearing member, any one of claims 1 to 9 develops the electrostatic latent image written on the outer peripheral surface of the photosensitive member to form a toner image And a transfer device that transfers the developed toner image to a recording medium.

  An image forming apparatus according to a twelfth aspect of the present invention is provided in the apparatus main body, and is detachably disposed in the middle of the recording medium conveyance path from the recording medium accommodation section to the recording medium discharge section, and the recording medium conveyance path. And a process cartridge according to claim 10.

  According to the developing apparatus of the first aspect of the present invention, it is possible to improving the cleaning of the image bearing member, and it is possible to suppress the reduction amount pumping of the two-component developer with time, the toner image The occurrence of density unevenness can be prevented.

  According to the developing device of the second aspect of the present invention, the conveyance performance of the two-component developer by the groove can be ensured, and the occurrence of uneven density in the toner image caused by the formation of the groove can be prevented. .

  According to the developing device of the third aspect of the invention, by reducing the developing gap “G” to 0.1 to 0.4 mm, it is possible to improve the granularity of the toner image and obtain a high-quality image. it can.

  According to the developing device of the fourth aspect of the present invention, an image having excellent dot reproducibility can be formed by the small particle size of the magnetic carrier.

  According to the developing device of the fifth aspect of the present invention, film scraping and spenting of the resin coat film can be suppressed, and the life of the magnetic carrier can be extended.

  According to the developing device of the sixth aspect of the invention, a high-quality image can be formed by using this toner.

  According to the developing device of the seventh aspect of the invention, by using this toner, a high-quality image with little background fog can be obtained.

  According to the developing apparatus of the invention of claim 8, wherein the fluidity is high suction force between toner particles becomes weak, and, since the adsorption force between the toner and the image bearing member is weakened, to increase the transfer rate it can.

  According to the developing device of the ninth aspect, dot reproducibility and transfer efficiency can be improved, and toner fluidity can be improved, and a high-quality image can be obtained.

  According to the process cartridge of the invention of claim 10, wherein, since including a developing device according to any one of claims 1 to 9, that the same effects as the invention of any one of claims 1 to 9 Can do.

  According to the image forming apparatus of the invention of claim 11, wherein, since including a developing device according to any one of claims 1 to 9, the same effects as the invention of any one of claims 1 to 9 be able to.

  According to the image forming apparatus of the twelfth aspect of the invention, since the process cartridge of the tenth aspect of the invention is provided, the same effect as that of the tenth aspect of the invention can be achieved.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal front view schematically showing the overall structure of a color laser printer (hereinafter referred to as “printer”) as an image forming apparatus. Four process cartridges 3Y, 3M, 3C, and 3B are detachably mounted in the apparatus main body 2 of the printer 1. Four process cartridges 3Y, 3M, 3C, 3B are arranged in the horizontal direction at equal intervals, these process cartridges 3Y, 3M, 3C, the transfer device 4 is disposed below the 3B. The process cartridges 3Y, 3M, 3C, and 3B form toner images of different colors (Y: yellow, M: magenta, C: cyan, B: black), and only the toner colors used are different. Are the same. For this reason, in the description in the specification, the subscripts Y, M, C, and B are omitted as necessary. An optical writing device 5 is disposed above the process cartridge 3 in the apparatus main body 2, and a plurality of paper feed cassettes 6 serving as recording medium storage units are attached to and detached from the process cartridge 3 and the transfer device 4 in the apparatus main body 2. It is installed as possible.

  In the apparatus main body 2, the recording medium conveying path 8 to the recording medium P separated and fed from the paper feed cassette within 6 is conveyed toward the sheet discharge tray 7 which is a recording medium discharge portion is formed, the recording medium A registration roller 9, a process cartridge 3, a transfer device 4, a fixing device 10 and the like are arranged along the conveyance path 8.

  The optical writing device 5 includes a light source, a polygon mirror, an fθ lens, a reflection mirror, and the like. Form.

  The process cartridge 3, as shown in FIG. 2, the cartridge case 11, the photoreceptor 12 as an image bearing member which is housed in the cartridge case 11, the charging device 13, developing device 14 is constituted by a cleaning device 15, etc. .

  The charging device 13 uniformly charges the surface of the photoconductor 12 by sliding the photoconductor 12 with a charging roller 13a to which an AC voltage is applied. Laser light modulated and deflected by the optical writing device 5 is irradiated to the surface of the photosensitive member 12 subjected to the charging process while being scanned. Then, an electrostatic latent image is formed on the surface of the photoreceptor 12. The formed electrostatic latent image is developed with toner supplied from the developing device 14 and becomes a toner image.

  The developing device 14 includes a casing 14a and a developing roller 14b that is a developer carrier disposed so as to be partially exposed from the opening of the casing 14a. Further, a first conveyance screw 14c, a second conveyance screw 14d, a regulation blade 14e, a toner concentration sensor 14f, and the like are provided in the casing 14a. The developing roller 14b includes a cylindrical developing sleeve 14g and a magnet 14h disposed therein.

  A two-component developer composed of a magnetic carrier and a negatively chargeable toner is accommodated in the casing 14a. The two-component developer is frictionally charged while being agitated and conveyed by the first conveying screw 14d and the second conveying screw 14c, and then carried on the surface of the developing roller 14b. Then, after the thickness of the layer is regulated by the regulating blade 14e, the layer is conveyed to a developing region facing the photoconductor 12, where toner is attached to the electrostatic latent image on the photoconductor 12. By this adhesion, a toner image is formed on the photoreceptor 12. The two-component developer whose toner has been consumed by the development is returned into the casing 14a as the developing roller 14b rotates.

  A partition wall 14i is provided between the first transport screw 14c and the second transport screw 14d. The partition wall 14i divides the first supply unit that accommodates the developing roller 14b, the first conveyance screw 14c, and the like and the second supply unit that accommodates the second conveyance screw 14d in the casing 14a. The first conveying screw 14c is rotationally driven by a driving unit (not shown) and supplies the two-component developer in the first supply unit to the developing roller 14b while conveying the two-component developer from the front side to the back side in the drawing. The two-component developer conveyed to the vicinity of the end of the first supply unit by the first conveyance screw 14c enters the second supply unit through an opening (not shown) formed in the partition wall 14i. In the second supply unit, the second conveyance screw 14d is rotationally driven by a driving unit (not shown), and conveys the two-component developer sent from the first supply unit in a direction opposite to that of the first conveyance screw 14c. The two-component developer conveyed to the vicinity of the end of the second supply unit by the second conveyance screw 14d returns to the first supply unit through the other opening (not shown) formed in the partition wall 14i. .

  Toner density sensor 14f is a sensor for detecting the magnetic permeability is provided in the bottom wall near the center of the second supply unit, and outputs a voltage corresponding to the magnetic permeability of the two-component developer passing over it. Since the magnetic permeability of the two-component developer shows a certain degree of correlation with the toner concentration, the toner layer degree sensor 14f outputs a voltage having a value corresponding to the toner concentration. This output voltage value is sent to a control unit (not shown). This control unit includes a RAM, in which Vtref, which is a target value of the output voltage from the toner density sensor 14f, is stored. Vtref is used to drive control of the toner conveying device (not shown). Specifically, the control unit drives and controls a toner conveying device (not shown) so that the value of the output voltage from the toner concentration sensor 14f is close to Vtref, and replenishes toner into the second supply unit. By this replenishment, the toner concentration in the two-component developer in the developing device 14 is maintained within a predetermined range. Such control is performed individually in the developing device 14 of each process cartridge 3.

  The toner image formed on the photoreceptor 12 is separated and fed from the paper feed cassette 6 and transferred onto a recording medium P that is conveyed by a conveyance belt described later. After the transfer, the surface of the photoconductor 12 is discharged by a static eliminator (not shown) after the transfer residual toner is cleaned by the cleaning device 15. Then, provided is uniformly charged for the next image forming by the charging device 13. Each process cartridge 3 is detachable from the apparatus main body 2 and is replaced when the end of its life is reached.

  The transfer device 4 includes a conveying belt 16, a driving roller 17, a stretching roller 18, four transfer bias rollers 19, and the like. The conveyor belt 16 is tensioned by the driving roller 17 and the stretching roller 18 and is rotated in the arrow direction (counterclockwise direction in the figure) by the driving roller 17 that is rotationally driven by a driving system (not shown). Each of the four transfer bias rollers 19 is applied with a transfer bias from a power source (not shown). Then, the transfer belt 16 is pressed from the back surface toward the photoconductor 12 to form a transfer nip. In each transfer nip, a transfer electric field is formed between the photoconductor 12 and the transfer bias roller 19 due to the influence of the transfer bias. The toner image formed on the photoreceptor 12 is transferred onto the recording medium P conveyed by the conveying belt 16 due to the influence of the transfer electric field and nip pressure. The toner images of the respective colors are transferred on the recording medium P in the order of Y, M, C, and K, and color toners are transferred onto the recording medium P conveyed by the conveying belt 16 by the overlapping transfer. An image is formed.

  Recording medium P on which the color toner image has been formed is sent to a fixing device 10. The fixing device 10 forms a fixing nip by a heating roller 10a having a heat source such as a halogen lamp inside and a pressure roller 10b pressed against the heating roller 10a. The toner image is fixed by sandwiching the recording medium P in the fixing nip and applying heat and pressure. The recording medium P on which the toner image is fixed is discharged onto the paper discharge tray 7 through a pair of paper discharge rollers (not shown).

  Under such a configuration, characteristic portions of the present embodiment will be described.

  As shown in FIG. 3, the photosensitive member 12 and the developing roller 14 b provided in the process cartridge 3 are arranged to face each other with a dimension of the developing gap “G”.

  A plurality of grooves 20 extending in parallel with the center line of the developing roller 14b are formed on the outer peripheral surface of the developing sleeve 14g.

  The development sleeve 14g is manufactured as follows. First, aluminum is extruded hot to form a cylindrical shape. As the material of the developing sleeve 14g, brass, stainless steel, conductive resin or the like can be used in addition to aluminum, but aluminum is often used from the viewpoint of cost and accuracy. Next, a groove extending in parallel to the center line on the outer peripheral surface of the developing sleeve 14g is obtained by cold-drawing cylindrical aluminum from the inner peripheral surface of the die having a V-shaped convex portion formed on the inner peripheral surface. 20 is formed. Here, the inner diameter of the die may be slightly smaller than the outer diameter of the developing sleeve 14g, and processing for increasing the runout accuracy of the developing sleeve 14g may be performed simultaneously with the processing of the groove 20. The number of grooves 20 is about 50 to 100 when the outer diameter of the developing sleeve 14g is φ18 mm. The groove 20 can also be formed simultaneously with the hot extrusion production of aluminum.

  The developer used in the developing device 14 is a two-component developer composed of a magnetic carrier and toner. The toner contains at least an electrostatic charge developing base toner containing at least a binder resin and a colorant and inorganic fine particles. The average particle size of the inorganic fine particles is 30 to 160 nm.

  Here, it is disclosed in Patent Document 1 described above that the toner contains inorganic fine particles having an average particle diameter of 30 to 160 nm, so that the cleaning property from the photoreceptor 12 is improved.

  However, the inventor's research has revealed that the contained inorganic fine particles accumulate in the developing device 14 over time, thereby reducing the pumping amount at the time of diameter. Usually, in a color printer, a color copying machine, and the like, the outer peripheral portion of the developing sleeve is appropriately roughened by sandblasting to assist the developer conveying force. The developing sleeve subjected to the sandblast treatment is inferior to the developing sleeve 14g in which the groove 20 described in the present embodiment is formed in wear resistance, and wears in diameter (roughened projections disappear). The force to convey the developer staying behind the blade 14e decreases. Therefore, the wear of 径時, pick-up amount the developer is lowered. Furthermore, the deposited inorganic fine particles are interposed as spacers between the magnetic carriers of the developer, making it difficult to construct a carrier chain.

  Therefore, as in this embodiment, in order to improve the cleaning property, toner containing 30 to 160 nm inorganic fine particles is used, and by using the developing sleeve 14g in which the groove 20 is formed on the outer peripheral surface, resistance is improved. It has excellent wear properties and does not cause a decrease in pumping amount over time due to wear, and can maintain a sufficient conveying force over a long period of time.

  FIG. 4 is a graph showing experimental results of changes over time in the amount of pumped developer by the developing roller having the developing sleeve subjected to the sandblasting process and the developing roller 14b having the developing sleeve 14g having the groove 20 formed therein. . Incidentally, the toner silica 120nm as the inorganic particles are contained wt1%. As can be seen from the graph of FIG. 4, the use of the developing roller 14b including the developing sleeve 14g having the groove 20 can suppress a decrease in the pumping amount of the developer, thereby suppressing a decrease in the density of the toner image. It is possible to prevent an increase in toner concentration (toner scattering) due to prevention of ear marks) and a decrease in developing ability.

  In the present embodiment, the depth of the groove 20 formed in the developing sleeve 14g is 0.05 to 0.15 mm from the surface of the developing sleeve 14g. In addition, the groove depth deviation is set to 30% or less.

  When the depth of the groove 20 is too deep, the pitch unevenness of the groove 20 is generated, and when it is too shallow, the conveying force becomes insufficient. For this reason, as shown in FIG. 3, the depth dimension “H” of the groove 20 is set to 0.05 to 0.15 mm. Further, if there is a deviation in the depth of the groove 20, density unevenness occurs at one circumference pitch of the developing roller 14 b due to the deviation, so the groove depth deviation is preferably set to 30% or less. When the groove depth deviation is suppressed to 30% or less, a high-quality image in which density unevenness due to the groove depth deviation is suppressed can be obtained.

  In the present embodiment, the development gap “G” between the photoconductor 12 and the developing roller 14b is 0.1 to 0.4 mm.

  The development gap “G” is set to 0.4 mm or less, and the development gap “G” is narrowed compared to the conventional case. Compared with the case where the development gap “G” is wider than 0.4 mm, the granularity of the toner image is greatly improved, and a high-quality image can be obtained. If the development gap “G” is less than 0.1 mm, the toner is likely to adhere to the developing roller 14b. Therefore, the development gap “G” is desirably 0.1 mm or more.

  In the present embodiment, as described above, the developer is a two-component developer composed of a magnetic carrier and a toner, and the particle size of the magnetic carrier is 20 to 50 μm.

  By reducing the particle size of the magnetic carrier, an image with better dot reproducibility can be formed. Specifically, the size of the particle size of the magnetic carrier, 20 to 50 m is preferable. By setting the particle size of the magnetic carrier to 20 to 50 μm, which is smaller than the conventional range, it is possible to uniformly reduce the thickness of the developer spike (carrier chain) during image formation. Therefore, it is possible to deliver a more precise toner. Further, since the density of developer spikes per unit area on the developing roller 14b increases, toner can be delivered to the latent image on the photoconductor 12 without any gap. Thereby, an image with more excellent dot reproducibility can be formed.

  If the particle size of the magnetic carrier is too larger than 50 μm, the total surface area of the magnetic carrier is reduced and the amount of toner held is reduced when compared with the same amount of magnetic carrier. For this reason, the toner density is lowered. Increasing the amount of developer pumped up can maintain the developing ability, but toner sticking tends to occur. On the other hand, if the particle size of the magnetic carrier is too smaller than 20 μm, the magnetic force holding force by the magnet 14 h provided inside the developing roller 14 b is reduced, causing the magnetic carrier to scatter, and the magnetic carrier to the photoconductor 12. Adhesion increases.

  In this embodiment, using the magnetic carrier 21 as shown in FIG. This magnetic carrier 21 uses ferrite 21a as a core material, and the surface of the ferrite 21a is a resin coating film 21b in which a charge adjusting agent is contained in a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin. It is covered with. The resin coat film 21b has a resilient and strong adhesion. Further, large-diameter particles 21c having a diameter larger than the film thickness of the resin coat film 21b, for example, alumina particles are dispersed on the surface. The large particle 21c is held with a strong adhesive force of the resin coat film 21b.

  The conventional magnetic carrier was configured based on the idea of obtaining a long life while gradually scraping off the hard coat film, whereas the resin coat film 21b of the magnetic carrier 21 of the present embodiment has elasticity. Thus, the impact can be absorbed and film scraping can be suppressed. Further, by dispersing the large-diameter particles 21c having a diameter larger than the film thickness on the surface of the magnetic carrier 21, it is possible to prevent the impact on the resin coat film 21b and to clean the spent material. As described above, since the resin coating film 21b can be prevented from being scraped and spent, it is possible to achieve a longer life as compared with the conventional magnetic carrier. Thereby, it is possible to expect stabilization of the developer pumping amount, that is, stabilization of image quality over a long period of time.

  In this embodiment, the toner has 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 a release agent, the crosslinking reaction in an aqueous medium or elongation reacted, or are formed by crosslinking reaction and elongation reaction.

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 of the polyester 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 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 , 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, 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 salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade 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 Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl 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.

  In this embodiment, 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 1.00 to 1.40. Is set in the range.

  In order to reproduce fine 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, and a high-quality image with little background fogging can be obtained. can do.

  In the present embodiment, 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 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. 6 and 7 are explanatory diagrams schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2 of the toner. 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 is a true sphere, and becomes larger as the value of SF-1 increases.

  The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner 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 SF-2 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 (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

  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 photoconductor 12 becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity becomes high. Further, the attracting force between the toner and the photoconductor 12 is weakened, and the transfer rate from the photoconductor 12 to the recording medium P is increased. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

  In the present embodiment, the toner has a substantially spherical shape, and the shape is defined by a major axis r1, a minor axis r2, and a thickness r3 (provided that r1 ≧ r2 ≧ r3), and the major axis r1 and the minor axis are short. The ratio (r2 / r1) to the axis r2 is in the range of 0.5 to 1.0, and the ratio (r3 / r2) of the thickness r3 to the minor axis r2 is in the range of 0.7 to 1.0. .

  The shape of the toner is substantially spherical and can be expressed by the following shape rule. FIG. 8 is an explanatory diagram schematically showing the shape of the toner. In FIG. 8, 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 this embodiment has a major axis and a minor axis. The ratio (r2 / r1) to the axis (see FIG. 8B) is 0.5 to 1.0, and the ratio (r3 / r2) between the thickness and the minor axis (see FIG. 8C) is 0. It is preferable that it exists in the range of 7-1.0.

  If 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 the separation from the true spherical shape, and high 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.

  In addition, r1, r2, r3 can be measured by the following method, for example. That is, the toner is uniformly dispersed and adhered onto a smooth measurement surface, and 100 particles of the toner are magnified 500 times with a color laser microscope “VK-8500” (manufactured by Keyence Corporation) to obtain the 100 toners. The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values.

  In this embodiment, the printer 1 including the process cartridge 3 is described as an example of the image forming apparatus. However, the present invention is not limited to an image forming apparatus using the process cartridge 3, and the apparatus main body. The present invention can also be applied to an image forming apparatus of a type provided with a photosensitive member and a charging device, a developing device, a cleaning device and the like disposed around the photosensitive member.

1 is a longitudinal front view schematically showing the overall structure of a color laser printer according to an embodiment of the present invention. It is a vertical front view which shows a process cartridge. It is a longitudinal front view showing a developing roller and a photoconductor. It is a graph which shows the experimental result of the time-dependent change of the pumping amount of a developer. It is a schematic diagram which shows the structure of a magnetic carrier. FIG. 3 is an explanatory diagram schematically showing the shape of a toner in order to explain a toner shape factor SF-1. FIG. 3 is an explanatory diagram schematically showing the shape of a toner in order to explain a toner shape factor SF-2. FIG. 3 is an explanatory diagram schematically illustrating the shape of a toner. It is the schematic of the developing roller currently used with the image development apparatus of a prior art example. It is the schematic of the image development apparatus of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Device main body 3 Process cartridge 4 Transfer device 5 Optical writing device 6 Recording medium storage part 7 Recording medium discharge part 8 Recording medium conveyance path 11 Cartridge case 12 Image carrier 13 Charging device 14 Developing device 14b Developer carrier 20 Groove 21 Magnetic carrier 21a Core material 21b Resin coated film

Claims (12)

A roller-shaped developer carrier disposed opposite to the image carrier with a development gap “G” and rotatable about a center line; and a two-component developer comprising a magnetic carrier and a toner. In a developing device that forms a toner image by developing an electrostatic latent image formed on the image carrier with toner in a two-component developer carried and carried on an agent carrier.
The toner contains a base toner for electrostatic charge development containing at least a binder resin and a colorant, and inorganic fine particles having an average particle size of 30 to 160 nm,
A plurality of grooves extending in parallel with the center line of the developer carrier are formed on the surface of the developer carrier.
A developing device.   Wherein the depth of the groove is 0.05~0.15mm from the surface of the developer carrying member, a developing apparatus according to claim 1, wherein the deviation of the groove depth is 30% or less.   The developing device according to claim 1, wherein the developing gap “G” is 0.1 to 0.4 mm.   4. The developing device according to claim 1, wherein the magnetic carrier has a particle size of 20 to 50 [mu] m.   The magnetic carrier is characterized in that a magnetic core material is coated with a resin coat film, and the resin coat film contains a resin component obtained by crosslinking a thermoplastic resin and a melanin resin, and a charge control agent. The developing device according to claim 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 subjected to a crosslinking reaction and an extension reaction in an aqueous medium. The developing device according to claim 1, wherein the developing device is obtained by at least one of the following reactions.   The toner has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) of 1.00 to 1.40. The developing device according to any one of claims 1 to 6.   The toner shape factor SF-1 is 100 to 180, a developing apparatus as claimed in to shape factor SF-2 of claims 1, characterized in that 100 to 180 7.   The toner has a substantially spherical shape, and when the shape is a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the ratio of the major axis r1 to the minor axis r2 ( r2 / r1) is 0.5 to 1.0, any of claims 1 to 8 ratio of the thickness r3 to the minor axis r2 (r3 / r2) is characterized in that 0.7 to 1.0 A developing device according to claim 1. An image carrier on which a toner image is formed on the outer peripheral surface;
A cartridge case for rotatably holding the image carrier;
The developing device according to any one of claims 1 to 9, wherein the developing device is provided in the cartridge case and is disposed to face an outer peripheral surface of the image carrier.
A process cartridge comprising: An image carrier on which a toner image is formed on the outer peripheral surface;
A charging device for uniformly charging the outer peripheral surface of the image carrier;
An optical writing device for writing an electrostatic latent image on the outer peripheral surface of the uniformly charged image carrier;
The developing device according to claim 1, wherein the electrostatic latent image written on the outer peripheral surface of the photosensitive member is developed to form a toner image;
A transfer device for transferring the developed toner image to a recording medium;
An image forming apparatus comprising: A recording medium conveyance path provided in the apparatus main body and extending from the recording medium storage unit to the recording medium discharge unit;
The process cartridge according to claim 10, wherein the process cartridge is detachably disposed in the middle of the recording medium conveyance path;
An image forming apparatus comprising:

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