JP2006065177A - Developing device, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish high quality image formation by preventing nonuniform density and soiled base, which are caused by developer flocculating in the position where a developing roller and a developer layer thickness regulating member face each other. <P>SOLUTION: The developing device includes the developing roller 29 for supplying developer held thereon to an image carrier 2 having an electrostatic latent image formed on it; the developer layer thickness regulating member 32 for regulating the layer thickness of the developer held by the developing roller 29; and an air spray mechanism 35 for spraying air to a part located near the position where the developing roller 29 and the developer layer thickness regulating member 32 face each other and upstream of the developing roller 29 in the direction of the rotation of the developing roller 29. The developer tends to flocculate in the part near the position where the developing roller 29 and the developer layer thickness regulating member 32 face each other and upstream of the developing roller 29 in the direction of the rotation of the roller 29. By spraying air to the part by the air spray mechanism 35, the flocculating developer can be caused to fly and scatter. This prevents nonuniform image density and soiled base, which are caused by developer flocculation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device capable of preventing toner aggregation, an image forming apparatus using the developing device, and a process cartridge.

  As an example of the developing device, one in which a developing roller, a developer layer thickness regulating member, a stirring member and the like are accommodated in a developing container together with a developer is known (see Patent Documents 1 and 2). As the developer, a one-component developer composed only of toner and a two-component developer composed of toner and carrier are used.

  In such a developing device, the developer is conveyed to the vicinity of the developing roller by the stirring member, and the conveyed developer is passed between the developing roller and the developer layer thickness regulating member, so that the toner is triboelectrically charged. The applied toner is adhered to the developing roller with a uniform thickness.

  The toner is obtained by mixing a base resin with CCA (charge control agent) and rubbing it with a developer layer thickness regulating member. Further, an additive mainly composed of an inorganic substance is injected around the base resin of the toner, and this additive reduces non-electrostatic adhesion with other toner or developer layer thickness regulating members. However, the additive itself may be charged and often contributes to toner charging.

JP 2002-148937 A JP-A-11-15262

  However, the hardness of the base resin is extremely lower than that of metal or the like, and it has been reported that the toner additive is buried in the base resin as the image forming process is repeated. When the additive is buried in the base resin, the fluidity of the toner is lowered and the toners are likely to adhere to each other. As a result, the developer (toner) adhesion amount on the developing roller increases, or the coverage area of the additive with respect to the base resin decreases and the toner charge amount decreases, so that the developing ability changes.

  As a result, as the image, an excessive image density due to an increase in the adhesion amount on the developing roller, an image density decrease due to a decrease in charging ability, and the like occur. In particular, when the charging ability is reduced, the toner obtains electric charge by rubbing against the developer layer thickness regulating member, so that density unevenness (charging) occurs at the next print output after the print output. (Thinning due to a decrease in the amount) occurs. Specifically, there is no problem when the print output is frequently performed, but if left for a long time, the toner attached on the developing roller passes between the developing roller and the developer layer thickness regulating member. Since the amount of charge is different before (after the toner rubs against the member) and after passing, there is a difference in density on the image between the first round corresponding to the rotation cycle of the developing roller and thereafter. Then, the density of the image area on the first round of the developing roller is low, and after that, the density is normal, and density unevenness is observed in the entire image. This is inconspicuous when there are few solid images, such as a character image, but becomes noticeable when there are many solid images.

  In recent years, toner for low-temperature fixing has been increasingly used for energy saving, and since the base resin of the toner has become softer for fixing at low temperature, the above-described density unevenness has been a problem.

  The problem of density unevenness is when the developer fluidity is reduced and agglomerated in the vicinity of the position where the developing roller and the developer layer thickness regulating member face each other and upstream in the rotation direction of the developing roller. It becomes more prominent. Further, when the developer aggregates, the gap between the developing roller and the developer layer thickness regulating member becomes large, and the amount of developer that rubs through between the developing roller and the developer layer thickness regulating member increases. Dirt is generated.

  The object of the present invention is caused by the fact that the developer aggregates in the vicinity of the facing position between the developing roller and the developer layer thickness regulating member and at the upstream position along the rotation direction of the developing roller. It is to perform high-quality image formation by preventing image density unevenness and background contamination.

  The developing device according to the first aspect of the present invention includes a developing roller that carries a developer, and that can rotate around a center line that supplies the carried developer to an image carrier on which an electrostatic latent image is formed, and the developing roller A developer layer thickness regulating member that is disposed to face the outer circumferential surface of the developer roller and regulates the layer thickness of the developer carried by the developing roller; and in the vicinity of the opposed position of the developing roller and the developer layer thickness regulating member. And removing means for removing the developer aggregated at the upstream position along the rotation direction of the developing roller.

  According to a second aspect of the present invention, in the developing device according to the first aspect, the removing means is in the vicinity of a position where the developing roller and the developer layer thickness regulating member are opposed to each other and along the rotation direction of the developing roller. An air blowing mechanism that blows air to a position on the upstream side.

  According to a third aspect of the present invention, in the developing device according to the first aspect, the removing means is in the vicinity of a position where the developing roller and the developer layer thickness regulating member are opposed to each other and along the rotation direction of the developing roller. And a developer suction mechanism that sucks the developer located on the upstream side.

  According to a fourth aspect of the present invention, in the developing device according to any one of the first to third aspects, the toner occupying at least a part of the developer has a circularity of 0.9 or more.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier; a charging device that uniformly charges the outer peripheral surface of the image carrier; and an electrostatic charge on the outer peripheral surface of the uniformly charged image carrier. 5. An optical writing device for writing a latent image; a developing device according to claim 1 for developing a toner image by developing an electrostatic latent image written on an outer peripheral surface of the image carrier; A transfer device that transfers the toner image transferred onto the recording medium, and a fixing device that fixes the toner image transferred onto the recording medium.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the developing device includes a plurality of the developing devices arranged in a tandem type.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, the air spray mechanism or the developer suction mechanism is provided immediately after one print output job for transferring a toner image to the recording medium is completed. Means for driving.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, a density sensor that detects a toner density of a toner image on the image carrier, and the air blowing according to a detection result by the density sensor. A mechanism or a means for driving the developer suction mechanism.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the fifth or sixth aspect, a remaining amount sensor for detecting a remaining amount of the developer in the developing device, and the air according to a detection result by the remaining amount sensor. Means for driving the spray mechanism or the developer suction mechanism is provided.

  A process cartridge according to a tenth aspect of the present invention is an image carrier, a cartridge case for rotatably holding the image carrier, and the development according to any one of the first to fourth aspects accommodated in the cartridge case. An apparatus.

  According to the developing device of the first aspect of the present invention, the developer aggregates at a position in the vicinity of the position where the developing roller and the developer layer thickness regulating member face each other and upstream in the rotation direction of the developing roller. Although it is easy to remove the developer aggregated at this position by the removing means, it is possible to prevent unevenness in image density and background stain caused by the aggregation of the developer, and to improve the quality of the formed image. be able to.

  According to the developing device of the second aspect of the present invention, the developer aggregated by blowing air with the air blowing mechanism can be blown away and the density unevenness of the image generated due to the aggregation of the developer is reduced. Background stains can be prevented and the quality of the formed image can be improved.

  According to the developing device of the third aspect of the present invention, the aggregated developer can be removed by sucking the developer with the developer suction mechanism, and the density of the image generated due to the developer aggregation. Unevenness and background stains can be prevented, and the quality of the formed image can be improved.

  According to the developing device of claim 4, since the toner having a circularity of 0.9 or more is easy to roll, the stress applied when the toner passes between the developing roller and the developer layer thickness regulating member. , The embedding of the additive in the base resin of the toner can be suppressed, a decrease in fluidity can be suppressed, and the frequency of occurrence of developer aggregation can be reduced. For this reason, the frequency of driving the air blowing mechanism and the developer suction mechanism can be reduced, and the work efficiency of the image forming operation can be improved.

  According to the image forming apparatus of the fifth aspect of the present invention, it is possible to prevent density unevenness and background contamination during image formation, and to improve the quality of the formed image.

  According to the image forming apparatus of the sixth aspect of the present invention, in the case of forming a color image by forming different color toner images by each developing device, it is possible to prevent density unevenness and background stains from occurring during image formation. And the quality of the formed color image can be improved.

  According to the image forming apparatus of the seventh aspect of the invention, since the air blowing mechanism or the developer suction mechanism is driven immediately after the end of one job, the developer can be prevented from aggregating or agglomerated. The developer can be removed at an early stage, the density unevenness of the image and the background stain caused by the aggregation of the developer can be prevented, and the quality of the formed image can be improved, It is possible to perform a process of blowing away the aggregated developer to loosen it or remove it by suction without reducing the work efficiency of the image forming operation.

  According to the image forming apparatus of the eighth aspect, when the toner density of the toner image on the image carrier is equal to or lower than the set value, the cause is the opposite of the developing roller and the developer layer thickness regulating member. In some cases, the developer agglomerates at a position near the position and upstream of the developing roller in the rotation direction. In such a case, by driving an air blowing mechanism or a developer suction mechanism By blowing off and aggregating the agglomerated developer and removing it by suction, it is possible to prevent unevenness in image density and background stains caused by agglomeration of the developer, and to improve the quality of the formed image. be able to.

  According to the image forming apparatus of the ninth aspect of the invention, when the remaining amount of the developer in the developing device decreases, the flowability of the developer in the developing device decreases, and the developing roller, the developer layer thickness regulating member, In many cases, agglomeration of the developer is likely to occur at a position in the vicinity of the opposite position and upstream of the developing roller in the rotation direction. Therefore, depending on the detection result by the remaining amount sensor that detects the remaining amount of the developer in the developing device, the air blowing mechanism or the developer suction mechanism is driven to blow away the agglomerated developer to be loosened or sucked and removed. By doing this, it is possible to prevent unevenness in image density and background contamination caused by the aggregation of the developer, and to improve the quality of the formed image.

  According to the process cartridge of the tenth aspect of the present invention, the developer is aggregated by driving the air blowing mechanism or the developer suction mechanism to blow away the aggregated developer to be loosened or sucked and removed. Thus, it is possible to prevent uneven density and background smearing of the image, improve the quality of the formed image, and prevent the process cartridge from being shortened due to the aggregation of the developer.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a longitudinal side view showing a schematic configuration of a color laser printer (hereinafter referred to as “color printer”) which is a tandem type image forming apparatus provided with four developing devices of the present invention.

  This color printer 1 has a photoreceptor belt 2 as an image carrier, and around the photoreceptor belt 2, a charging device 3, an optical writing device 4, four developing devices 5Bk, 5C, 5M, 5Y, A transfer device 6 and a photoconductor cleaning device 7 are disposed. Further, in the color printer 1, conveyance for conveying the recording medium P that stores the recording medium P, the recording medium P that is stored in the sheet feeding cassette 8, or the recording medium P that is placed on the manual feed tray 9. A roller 10, a registration roller 11, a fixing device 12 and the like are provided. The subscripts Bk, C, M, and Y described above indicate the color of the image to be formed or the toner used (black, cyan, magenta, yellow), and these subscripts are omitted as necessary. To do.

  The photosensitive belt 2 is wound around the driving roller 13, the primary transfer counter roller 14 and the stretching roller 15, and is rotationally driven in the direction of arrow A by a driving motor connected to the driving roller 13. An organic photosensitive layer is formed on the surface of the photoreceptor belt 2.

  The charging device 3 uniformly charges the surface of the photoreceptor belt 2 by applying a voltage from a power source.

  The optical writing device 4 receives, for example, an optical writing signal obtained by converting an image signal sent from an external computer by an image signal processing unit (not shown), and generates a light source according to the optical writing signal. Laser light is emitted from (not shown), and the emitted laser light is irradiated onto the uniformly charged surface of the photoreceptor belt 2 through the polygon mirror 16, the f / θ lens 17, and the reflection mirror 18. . By this laser light irradiation, an electrostatic latent image corresponding to the image signal is formed on the surface of the photoreceptor belt 2. By supplying toner of each color from developing devices 5Bk, 5C, 5M, and 5Y, which will be described later, to the photosensitive belt 2 on which the electrostatic latent image is formed, the electrostatic latent image is developed and visualized as a toner image. It becomes.

  The transfer device 6 includes an intermediate transfer belt 19 on which the toner images of the respective colors formed on the photosensitive belt 2 are sequentially transferred, a driving roller 20 around which the intermediate transfer belt 19 is wound, a secondary transfer counter roller 21, A cleaning counter roller 22, a cleaning device 23 for cleaning the intermediate transfer belt 19, a primary transfer roller 24 for transferring (primary transfer) the toner image on the photosensitive belt 2 onto the intermediate transfer belt 19, and the intermediate transfer belt 19. The image forming apparatus includes a secondary transfer roller 25 and the like for transferring the toner image (color toner image) transferred thereon onto the recording medium P (secondary transfer). The intermediate transfer belt 19 is rotationally driven in the direction of arrow B by a drive motor connected to the drive roller 20.

  The fixing device 12 is conveyed from the paper feed cassette 8 or from the manual feed tray 9, and the toner image is transferred when passing through the secondary transfer position between the intermediate transfer belt 19 and the secondary transfer roller 25. This is a device for fixing the recorded recording medium P. This fixing process is performed by applying heat and pressure to the recording medium P on which the toner image has been transferred to melt the toner and welding the molten toner to the recording medium P. The recording medium P for which the fixing process has been completed is discharged onto a discharge tray 26 formed on the upper portion of the color printer 1.

  FIG. 2 is a longitudinal side view showing a schematic configuration of the developing device 5. The four developing devices 5Bk, 5C, 5M, and 5Y contain a one-component developer consisting only of toner as a developer, and the color of the toner is different among the developing devices 5Bk, 5C, 5M, and 5Y. The mechanical structures of the developing devices 5Bk, 5C, 5M, and 5Y are the same. Each developing device 5 includes a developing container 28 having an opening 27 toward the photosensitive belt 2, a developing roller 29 accommodated in the developing container 28, a toner supply roller 30, a plurality of toner conveying members 31, and a developer layer thickness regulation. A developer layer thickness regulating roller 32, which is a member, a bracket 33, a scraper 34 formed of a flexible material that is affixed to the bracket 33 and has a front end portion in contact with the outer peripheral surface of the developer layer thickness regulating roller 32, etc. It has.

  The developing roller 29 is rotatably provided around the center line, and is driven by a connected driving motor to rotate in the direction of arrow C. The toner conveying member 31 rotates to convey the toner in the developing container 28 to the developing roller 29 side. The toner supply roller 30 is disposed in contact with the outer peripheral surface of the developing roller 29 and supplies the toner to the developing roller 29 while precharging the toner. The developer layer thickness regulating roller 32 is disposed in contact with the outer peripheral surface of the developing roller 29, regulates the layer thickness of the toner carried by the developing roller 29, and frictionally charges the toner carried by the developing roller 29.

  Further, the developing device 5 is a removing unit that blows air to a position on the upstream side in the rotation direction of the developing roller 29 in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other. An air blowing mechanism 35 is provided. The air blowing mechanism 35 is formed by an air pump 36, a pipe 37 that guides air blown from the air pump 36, and a discharge port 38 that discharges the air guided through the pipe 37 in the developing container 28. The discharge port 38 is disposed in a direction near the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other and discharge air toward the upstream side along the rotation direction of the developing roller 29.

  A cam 39 that is independently rotatable is in contact with a side end (left side in the figure) of each developing device 5. One developing device 5 that develops a toner image causes the developing roller 29 to be moved by the action of the cam 39 and a biasing means (not shown) that biases the developing device 5 away from the photosensitive belt 2. The other three developing devices 5 that have moved to a position where they are brought into contact with the photosensitive belt 2 and do not develop a toner image have moved to a position where the developing roller 29 is separated from the photosensitive belt 2. FIG. 1 shows a state in which development is performed by the developing device 5Bk containing black toner, and only the developing device 5Bk moves to a position where the developing roller 29 is brought into contact with the photosensitive belt 2, and the other developing devices. 5C, 5M, and 5Y are moved to positions where the developing roller 29 is separated from the photosensitive belt 2.

  FIG. 3 shows a state in which the toner image is developed on the photosensitive belt 2 by the developing roller 29 rotating in the direction of arrow C. At this time, the developer layer thickness regulating roller 32 is stopped without being rotated by the bearing using the one-way clutch. As the developing operation continues, the toner aggregates in the wedge-shaped portion on the upstream side in the rotation direction of the developing roller 29 in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other. Toner 40 may be generated. When such agglomerated toner 40 is generated, it becomes difficult for the toner to be rubbed between the developing roller 29 and the developer layer thickness regulating roller 32, so that the charging ability is lowered and the image density is lowered. Further, when the aggregated toner 40 is generated, the gap between the developing roller 29 and the developer layer thickness regulating roller 32 becomes large, and the amount of toner that rubs between the developing roller 29 and the developer layer thickness regulating roller 32 is increased. Increases and soiling occurs.

  FIG. 4 shows a state in which the developing roller 29 is rotated in the direction of the arrow C ′ and the developer layer thickness regulating roller 32 is rotated in the direction indicated by the arrow D after the developing operation is completed in order to remove the aggregation toner 40. ing. By rotating the developing roller 29 in the direction of arrow C ′ and rotating the developer layer thickness regulating roller 32 in the direction of arrow D, the agglomerated toner 40 is placed between the developing roller 29 and the developer layer thickness regulating roller 32. The wedge-shaped portion is pushed back in the direction indicated by arrow E.

  FIG. 5 shows a state in which the air blowing mechanism 35 is driven and air is discharged from the discharge port 38 in combination with the operation of rotating the developing roller 29 shown in FIG. 4 in the direction of the arrow C ′. When the air is discharged from the discharge port 38, the scraper 34 formed of a flexible material is pushed up, and the direction indicated by the arrow E from the wedge-shaped portion between the developing roller 29 and the developer layer thickness regulating roller 32. The agglomerated toner 40 that has been pushed back to is blown away in the direction indicated by the arrow F and loosened. Thereby, when the developing operation is restarted, it is possible to prevent a decrease in image density and a background stain caused by the aggregated toner 40.

FIG. 6 is a block diagram showing the electrical connection of each unit provided in the color printer 1.
The color printer 1 includes a controller 41 for controlling each unit. The controller 41 centrally controls each unit (CPU) 42, and various programs executed by the CPU 42 are stored in a ROM ( A read only memory (RAM) 43, a RAM (Random Access Memory) 44 that functions as a work area for the CPU 42, and the like are connected by a bus line 45.

  The CPU 42 also detects an air pump 36 via a pump control unit 36a, a density sensor 46 that detects the toner density of the toner image formed on the photosensitive belt 2, and a remaining amount of toner in the developing device 5. A remaining amount sensor 47 is connected. As the density sensor 46, an optical sensor that can detect the density of a patch formed on the photosensitive belt 2 can be used. As the remaining amount sensor 47, an optical sensor that detects when the toner in the developing device 5 becomes a predetermined amount or less can be used.

  FIG. 7 is a flowchart for explaining the timing for driving the air blowing mechanism 35. The controller 41 determines whether or not one print output job has ended (step S1), and drives the air blowing mechanism 35 after one job ends (step S2). One job of print output ends when the emission of laser light based on the optical writing signal input to the optical writing device 4 ends. Accordingly, since the air blowing mechanism 35 is driven every time one job is completed, the generation of the aggregated toner 40 can be prevented in advance, or can be removed at an early stage before the aggregated toner 40 becomes large. . Accordingly, it is possible to prevent the density unevenness and background stain of the image caused by the aggregation toner 40 and to improve the quality of the formed image. In addition, since the air blowing mechanism 35 is driven immediately after the end of one job, there is no inconvenience that the efficiency of image forming work is reduced even if the air blowing mechanism 35 is driven.

  FIG. 8 is a flowchart for explaining another timing for driving the air blowing mechanism 35. At a preset timing, a patch for density detection is formed on the photosensitive belt 2 under the control of the controller 41 (step S11), and the toner density of the patch is detected by the density sensor 46 (step S12). Then, it is determined whether or not the detected toner density is less than or equal to a set value (step S13). If it is less than or equal to the set value, the air blowing mechanism 35 is driven (step S14). As a result, the aggregated toner 40 generated in the wedge-shaped portion on the upstream side in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other along the rotation direction of the developing roller 29 is blown off and loosened. In addition, it is possible to prevent density unevenness and background smearing caused by the aggregation toner 40, and to improve the quality of the formed image.

  FIG. 9 is a flowchart illustrating another timing for driving the air blowing mechanism 35. Based on the detection result of the remaining amount sensor 47, the controller 41 determines whether or not the remaining amount of toner in the developing device 5 has become a set value or less (step S21). In step S22, the air blowing mechanism 35 is driven. As a result, when the remaining amount of toner in the developing device 5 decreases, the fluidity of the toner in the developing device 5 decreases, and in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other, the developing roller The aggregated toner 40 is likely to be generated in the wedge-shaped portion on the upstream side along the rotation direction 29, but the generation of the aggregated toner 40 can be prevented in advance, or the aggregated toner 40 is removed at a small stage. Can do. Accordingly, it is possible to prevent the density unevenness and background stain of the image caused by the aggregation toner 40 and to improve the quality of the formed image.

Next, the toner used in the printer 1 will be described.
The toner used was such that the ratio of the projected area to the area by the average diameter of the toner particles was 96% or more. With normal pulverized toner, it is smaller than 96%. These toners are often produced by a polymerization method (emulsification, suspension, dispersion) or the like. It is also possible to make the toner diameter uniform. In this embodiment, the average particle diameter of the toner produced by the polymerization method is 6 μm, the base resin is polyester, and the additives are silica and titanium. The shape factor is 0.96. As a comparative example, a toner made by a conventional pulverization method has an average particle diameter of 6 μm, a base resin is polyester, and additives are silica and titanium. However, the shape factor is 0.85.

(Toner circularity measurement method)
It is important that the toner in the present invention has a specific shape. If the average circularity is less than 0.95 and the irregular shape is too far from the spherical shape, a satisfactory high transferability and a high-quality image free from dust are obtained. I can't get it.
As a shape measuring method, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. A toner having an average circularity of 0.96 or more, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle, is a high-definition image with a reproducibility of an appropriate density. It turned out to be effective in forming. More preferably, the average circularity is 0.960 to 0.998. This value can be measured as an average circularity by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measurement method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is obtained by performing dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

(Production method of spherical toner)
Examples of the method for producing a toner having a circularity of 0.96 to 1.00 according to the present invention include suspension polymerization, emulsion aggregation, dispersion polymerization, interfacial polymerization, dissolution suspension, and phase inversion emulsification. A production method by wet granulation is mentioned. Even with toner obtained by pulverization / classification of a melt-kneaded product, a toner having a high degree of circularity can be produced by heat treatment of the toner, but it is not desirable in terms of energy efficiency.
Among the above-mentioned wet granulation methods, suspension polymerization method and dispersion polymerization method are excellent in that a toner with a high degree of circularity can be stably obtained, a sharp particle size distribution can be obtained, and in terms of toner charge control. ing. Further, the dissolution suspension method is excellent in that a polyester resin advantageous in terms of low-temperature fixability of the toner can be used. Hereinafter, the suspension polymerization method, the dispersion polymerization method, and the dissolution suspension method will be described in detail.

(Suspension polymerization method)
For a specific monomer described later, a dispersion stabilizer, a colorant, and, if necessary, a crosslinking agent, a charge control agent, a release agent, and the like are uniformly dispersed by a ball mill or the like, and then a polymerization initiator is added thereto. In addition, a monomer phase is obtained, and the aqueous dispersion medium phase prepared by stirring with the monomer phase in advance is placed in a stirring tank, stirred with a homogenizer, etc., and the resulting suspension is heated after nitrogen substitution and subjected to a polymerization reaction. By completing the above, colored resin particles are obtained, and by washing and drying, colored toner particles can be obtained.

  The polymerizable monomer used for suspension polymerization is a monomer having a vinyl group, and specific examples thereof include the following monomers. That is, styrene such as styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, butyl styrene, octyl styrene, and derivatives thereof, and the styrene monomer is most preferable. . Other vinyl monomers include ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride, vinyl acetate and vinyl propionate. , Vinyl esters such as vinyl benzoate and vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid-2 -Ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, n methacrylate Α-methylene aliphatic monocarboxylic esters such as octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, acrylic acid or methacrylic acid such as acrylonitrile, methacrylonitrile, acrylamide Derivatives, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone N-vinyl compounds such as vinyl naphthalene and the like can be used, and these monomers can be used alone or in combination.

  In the suspension polymerization method, in order to form a crosslinked polymer in the monomer composition, the following crosslinking agent may be present for suspension polymerization. As a crosslinking agent, divinylbenzene, divinylnaphthalene, polyethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol diacrylate, Dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate , Trimethylol methane tetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate and the like. When the amount of the crosslinking agent used is too large, the toner is hardly melted by heat, and heat fixability and heat pressure fixability are inferior. In addition, if the amount of the crosslinking agent used is too small, properties such as blocking resistance and durability required for the toner are deteriorated, and in heat roll fixing, a part of the toner does not completely adhere to the paper and does not adhere to the roll surface. A cold offset occurs in which it adheres and is transferred to the next paper. Therefore, the amount of the crosslinking agent used is 0.001 to 15 parts by weight, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

  The following can be used as the dispersion stabilizer in the suspension polymerization method. That is, water-soluble polymers such as polyvinyl alcohol, starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, sodium polyacrylate, sodium polymethacrylate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay Diatomaceous earth, metal oxide powder, etc. are used. These are preferably used in the range of 0.1 to 10% by weight based on water.

  In the suspension polymerization method, the polymerization initiator may be added to the dispersion containing the monomer composition after granulation, but the polymerization initiator is uniformly applied to the individual monomer composition particles. From this, it is desirable to make it contain in the monomer composition before granulation. Such polymerization initiators include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis- (cyclohexane-1- Carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisbutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxide And peroxide polymerization initiators such as 2,4-dichloroylbenzoyl peroxide and lauryl peroxide.

  In the suspension polymerization method, a magnetic toner containing a magnetic material is possible. In order to obtain a magnetic toner, magnetic particles may be added to the monomer composition. Examples of the magnetic material that can be used in the present invention include powders of ferromagnetic metals such as iron, cobalt, and nickel, and powders of alloys and compounds such as magnetite, hematite, and ferrite. As the magnetic particles, particles having a particle size of 0.05 to 5 μm, preferably 0.1 to 1 μm are used. When producing a small particle toner, magnetic particles having a particle size of 0.8 μm or less are used. It is desirable to do. The magnetic particles are desirably contained in 10 to 60 parts by weight in 100 parts by weight of the monomer composition. These magnetic particles may be treated with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, although depending on the surface area of the magnetic particles or the density of hydroxyl groups present on the surface, the surface treatment agent is usually 5 parts by weight or less, preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the magnetic particles. Thus, sufficient dispersibility in the polymerizable monomer is obtained, and the toner physical properties are not adversely affected.

(Dispersion polymerization method)
A polymer dispersant that dissolves in the hydrophilic organic liquid is added to the hydrophilic organic liquid, and the polymer that is dissolved in the hydrophilic liquid is swollen by the hydrophilic liquid, or It is produced by adding one or two or more kinds of vinyl monomers which are hardly dissolved and polymerizing. Also included is a reaction in which polymer particles having a particle size distribution smaller than the target particle size and having a narrow particle size distribution are used to grow in the above-described system. The monomer used for the growth reaction may be the same monomer as that used to produce the seed particles or another monomer, but the polymer must not be dissolved in the hydrophilic organic liquid.

  Examples of the hydrophilic organic liquid as a monomer diluent used for the seed particle formation and seed particle growth reaction include methyl alcohol, ethyl alcohol, modified ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol. , T-butyl alcohol, s-butyl alcohol, t-amyl alcohol, 3-pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, alcohols such as ethylene glycol, glycerin, diethylene glycol, Methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol mono Chirueteru, and ether alcohols such as diethylene glycol monoethyl ether as a representative.

  These organic liquids can be used alone or in a mixture of two or more. In addition, by using the organic liquid other than alcohols and ether alcohols together with the above-described alcohols and ether alcohols, the organic liquid can be used under the condition that the organic liquid is not soluble in the generated polymer particles. It is possible to suppress the size of the generated particles, the coalescence of the seed particles, and the generation of new particles by carrying out the polymerization while changing the SP value of each. The organic liquid used in this case includes hydrocarbons such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, xylene, halogenated hydrocarbons such as carbon tetrachloride, trichloroethylene, tetrabromoethane, and ethyl ether. , Ethers such as dimethyl glycol, siloxane and tetrahydrofuran, acetals such as methylal and diethyl acetal, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexane, esters such as butyl formate, butyl acetate, ethyl propionate and cellosolve acetate , Acids such as formic acid, acetic acid, propionic acid, nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethyl sulfoxide, dimethylforma Sulfur, such as de, nitrogen-containing organic compounds, other water is also included.

  In addition, the type and composition of the mixed solvent can be changed at the start of polymerization, during polymerization, and at the end of polymerization to adjust the average particle size, particle size distribution, and drying conditions of the polymer particles to be produced.

  Suitable examples of the polymer dispersant used during seed particle production or growth particle production include acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, Acids such as fumaric acid, maleic acid or maleic anhydride, or acrylic monomers containing hydroxyl groups, such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-methacrylic acid β- Hydroxypropyl, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate Glycerol monoacrylate, glycerol monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc. Esters of compounds containing vinyl alcohol and a carboxyl group, such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic chloride, methacrylic chloride, etc. , Vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, etc. Limer or copolymer, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene laurylphenyl Polyoxyethylenes such as ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, and celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, or the above hydrophilic monomers and styrene, α-methylstyrene, vinyl Those having a benzene nucleus such as toluene or derivatives thereof, acrylonitrile, methacrylonitrile, Copolymers with acrylic acid or methacrylic acid derivatives such as chloramide, and copolymers with crosslinkable monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, divinylbenzene and the like can also be used.

  These polymer dispersants are appropriately selected depending on the hydrophilic organic liquid to be used, the seeds of the intended polymer particles, and the production of the seed particles or the growth particles. In order to prevent stericity mainly, a polymer having a high affinity and adsorbability to the polymer particle surface and a high affinity and solubility to a hydrophilic organic liquid is selected. Further, in order to enhance the repulsion between particles in a three-dimensional manner, a molecular chain having a certain length, preferably a molecular weight of 10,000 or more is selected. However, if the molecular weight is too high, the viscosity of the liquid is remarkably increased, the operability and the stirrability are deteriorated, and the precipitation probability of the produced polymer on the particle surface varies. In addition, it is also effective for stabilization that a part of the monomer of the polymer dispersant listed above is allowed to coexist with the monomer constituting the target polymer particle.

  Further, together with these polymer dispersants, metals such as cobalt, iron, nickel, aluminum, copper, tin, lead, magnesium or alloys thereof (particularly those having a particle size of 1 μm or less are preferable), iron oxide, copper oxide, nickel oxide, Inorganic compound fine powders of oxides such as zinc oxide, titanium oxide, silicon oxide, higher alcohol sulfate ester salts, alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters and other anionic surfactants, alkylamine salts, Amine salt types such as amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, and quaternary ammonia such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridium salt, alkylisoquinolinium salt, benzethonium chloride, etc. Um salt-type cationic surfactants, fatty acid amide derivatives, non-ionic surfactants such as polyhydric alcohol derivatives, for example amino acids such as alanine type "for example dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine" Even if the amphoteric surfactant of the type or betaine type is used in combination, the stability of the produced polymer particles and the improvement of the particle size distribution can be further enhanced.

  In general, the amount of the polymer dispersant used for producing the seed particles varies depending on the type of the polymerizable monomer for forming the target polymer particles, but is preferably 0.1 to 10% by weight, preferably based on the hydrophilic organic liquid. Is 1 to 5% by weight. When the concentration of the polymer dispersion stabilizer is low, the polymer particles produced have a relatively large particle size, and when the concentration is high, a small particle size can be obtained. Even if it is used beyond, there is little effect on diameter reduction.

  The vinyl monomer is soluble in a hydrophilic organic liquid. For example, styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl. Ethylene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene Styrenes such as pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, 3,4-dichloro styrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic Isobutyl acid, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Α-methyl fatty acid monocarboxylic acid esters such as n-octyl acid, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylonitrile , Vinyl halides such as acrylic acid or methacrylic acid derivatives such as methacrylonitrile and acrylamide, vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Mixtures of singly or cross made of and their containing more than 50 wt% means a mixture of mutual with monomers capable of copolymerizable therewith.

  In addition, the polymer in the present invention may be polymerized in the presence of a so-called cross-linking agent having two or more polymerizable double bonds in order to improve offset resistance. Preferred crosslinking agents include divinylbenzene, divinylnaphthalene and their aromatic divinyl compounds, other ethylene glycol dimethacrylate, diethylene glycol methacrylate, triethylene glycol methacrylate, trimethylolpropane triacrylate, allyl methacrylate, tert-butyl. Diethylenic carboxylic acid esters such as aminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, all divinyl compounds such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, and three The compound which has the above vinyl group is mentioned, These are used individually or in mixture.

  When the growth polymerization reaction is subsequently performed using the seed particles thus crosslinked, the inside of the growing polymer particles is crosslinked. On the other hand, when the above-mentioned crosslinking agent is contained in the vinyl monomer solution used for the growth reaction, a polymer having a cured particle surface can be obtained.

  Examples of the purpose of adjusting the average molecular weight include compounds having a large chain transfer constant in the presence of polymerization, such as low molecular compounds having a mercapto group, carbon tetrachloride, and carbon tetrabromide.

  Examples of the polymerization initiator for the monomer include azo polymerization initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), and lauryl. Peroxide polymerization initiators such as peroxide, benzoyl peroxide, t-butyl peroctoate, peroxide polymerization initiators such as potassium persulfate, and systems using sodium thiosulfate, amine, etc. in combination with this Used. The polymerization initiator concentration is desirably 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer.

  The polymerization conditions for obtaining the seed particles are determined by the polymer dispersant in the hydrophilic organic liquid, the concentration of the vinyl monomer, and the compounding ratio according to the target average particle size and target particle size distribution of the polymer particles. Is done. In general, if the average particle size of the particles is to be reduced, the concentration of the polymer dispersant is set high, and if the average particle size is to be increased, the concentration of the polymer dispersant is set low. On the other hand, if the particle size distribution is to be made very sharp, the vinyl monomer concentration is set low, and if a relatively wide distribution may be used, the vinyl monomer concentration is set high.

  Particles are produced by completely dissolving a polymer dispersion stabilizer in a hydrophilic organic liquid, and then one or more vinyl monomers, a polymerization initiator, and other inorganic fine powders, surfactants, dyes if necessary. Add pigment, etc., and stir at normal speed of 30 to 300 rpm, preferably at low speed, and at a speed that makes the flow in the tank uniform using a turbine type stirring blade rather than a paddle type However, the polymerization is carried out by heating at a temperature corresponding to the polymerization rate of the polymerization initiator used. In addition, since the temperature at the initial stage of polymerization has a great influence on the kind of particles to be generated, it is desirable to raise the temperature to the polymerization temperature after adding the monomer and to add the polymerization initiator dissolved in a small amount of solvent. In the polymerization, it is necessary to sufficiently expel oxygen in the air in the reaction vessel with an inert gas such as nitrogen gas or argon gas. If the oxygen purge is insufficient, fine particles are likely to be generated. In order to perform the polymerization in a high polymerization rate range, a polymerization time of 5 to 40 hours is required, but the polymerization is stopped in a desired particle size, particle size distribution state, or a polymerization initiator is sequentially added, The polymerization rate can be increased by carrying out the reaction under high pressure.

  After completion of the polymerization, the polymer slurry may be used as it is in the dyeing process, or after removing unnecessary fine particles, residual monomers, polymer dispersion stabilizer, etc. by operations such as sedimentation separation, centrifugation, and decantation. However, if the dispersion stabilizer is not removed, the stability of the dyeing is higher and unnecessary aggregation is suppressed.

  Dyeing in the dispersion polymerization method is as follows. That is, the resin particles are dispersed in an organic solvent that does not dissolve the resin particles, the dye is dissolved in the solvent before or after this, the dye is infiltrated into the resin particles and colored, and then the organic solvent is removed. In the method for producing a dyed toner, the relationship between the solubility of the dye in the organic solvent (D1) and the solubility of the dye in the resin of the resin particle A (D2) is (D1) / (D2) A dye satisfying ≦ 0.5 is selectively used. As a result, a toner in which the dye has penetrated (diffused) to the deep part of the resin particles can be efficiently produced. The solubility in this specification is defined as measured at a temperature of 25 ° C. The solubility of the dye in the resin has the same definition as the solubility of the dye in the solvent, and means the maximum amount that the dye can be contained in the resin in a compatible state. Observation of the dissolved state or the deposited state of the dye can be easily performed by using a microscope. In order to know the solubility of the dye in the resin, an indirect observation method may be used instead of the direct observation method described above. In this method, a liquid having a solubility coefficient close to that of the resin, that is, a solvent that dissolves the resin well, and the solubility of the dye in this solvent may be determined as the solubility in the resin.

As a dye used for coloring, the ratio (D1) / (D2) of the dye to the resin constituting the resin particles is 0.5 or less from the solubility (D1) of the dye in the organic solvent used as described above. Need to be. Furthermore, it is preferable that (D1) / (D2) be 0.2 or less. The dye is not particularly limited as long as it satisfies the above-mentioned solubility characteristics, but water-soluble dyes such as cationic dyes and anionic dyes may have a large environmental fluctuation, and the electrical resistance of the toner is lowered, resulting in a decrease in transfer rate. Since there is a possibility, use of a vat dye, a disperse dye, and an oil-soluble dye is preferable, and an oil-soluble dye is particularly preferable. Also, several kinds of dyes can be used in combination depending on the desired color tone. The ratio (weight) between the dye to be dyed and the resin particles is arbitrarily selected depending on the degree of coloring, but is usually used in a ratio of 1 to 50 parts by weight of the dye with respect to 1 part by weight of the resin particles. Is preferred. For example, when an alcohol such as methanol or ethanol having a high SP value is used as the dyeing solvent and a styrene-acrylic resin having an SP value of about 9 is used as the resin particle, examples of the dye that can be used include: And dyes such as
CI SOLVENT YELLOW (6,9,17,31,35,1,102,103,105)
CI SOLVENT ORANGE (2,7,13,14,66)
CI SOLVENT RED (5,16,17,18,19,22,23,143,145,146,149,150,151,157,158)
CI SOLVENT VIOLET (31,32,33,37)
CI SOLVENT BLUE (22,63,78,83-86,91,94,95,104)
CI SOLVENT GREEN (24,25)
CI SOLVENT BROWN (3,9) etc.
Commercially available dyes include, for example, Aizen SOT dyes Yellow-1,3,4, Orange-1,2,3, Scarlet-1, Red-1,2,3, Brown-2, Blue-1, manufactured by Hodogaya Chemical Co., Ltd. 2, Violet-1, Green-1,2,3, Black-1,4,6,8, Sudan dyes manufactured by BASF, Yellow-140, 150, Orange-220, Red-290, 380, 460, Blue -670 and Mitsubishi Chemical's dialresin, Yellow-3G, F, H2G, HG, HC, HL, Orange-HS, G, Red-GG, S, HS, A, K, H5B, Violet-D, Blue- Oil color made by J, G, N, K, P, H3G, 4G, Green-C, Brown-A and Orient Chemical, Yellow-3 , GG-S, # 105, Orange-PS, PR, # 201, Scarlet- # 308, Red-5B, Brown-GR, # 416, Green-BG, # 502, Blue-BOS, HN, Black-HBB, # 803, EE, EX, Sumitomo Chemical's Sumiplast, Blue GP, OR, Red FB, 3B, Yellow FL7G, GC, Nippon Kayaku Kayalon, Polyester Black EX-SH3, Kaya Set Red-B Blue A-2R or the like can be used. Of course, the dye is appropriately selected depending on the combination of the resin particles and the solvent used at the time of dyeing, and is not limited to the above example.

  As an organic solvent for dyeing used for dyeing a resin particle, one in which the resin particle to be used does not dissolve or that slightly swells, specifically, the difference in solubility parameter (SP value) is 1. 0.0 or more, preferably 2.0 or more is used. For example, for styrene-acrylic resin particles, alcohols such as methanol, ethanol and n-propanol having a high SP value, or n-hexane and n-heptane having a low SP value are used. If the SP value difference is too large, wetting with respect to the resin particles becomes poor, and good dispersion of the resin particles cannot be obtained. Therefore, the optimum SP value difference is preferably 2 to 5.

  After dispersing the resin particles in the organic solvent in which the dye is dissolved, it is preferable to keep the liquid temperature below the glass transition temperature of the resin particles and stir. Thereby, it is possible to dye while preventing aggregation of the resin particles. The stirring may be performed using a commercially available stirrer such as a homomixer or a magnetic stirrer. Alternatively, a dye may be directly added to a slurry obtained at the end of polymerization by dispersion polymerization or the like, that is, a dispersion in which polymer resin particles are dispersed in an organic solvent, and heated and stirred under the above conditions. When the heating temperature exceeds the glass transition temperature, fusion between the resin particles occurs. The method for drying the slurry after dyeing is not particularly limited, but may be directly dried under reduced pressure without filtering or filtering after filtration. In the present invention, the colored particles obtained by air-drying or drying under reduced pressure after being separated by filtration in the present invention are hardly agglomerated and are reproduced with almost no loss of the particle size distribution of the charged resin particles.

(Dissolution suspension method)
Next, a method for producing spherical toner particles by the dissolution suspension method will be described. The dissolution suspension method is a method in which a resin is dissolved in a solvent to prepare an oil phase, emulsified in an aqueous phase composed of an aqueous medium, and then the solvent in the emulsified dispersion is removed to obtain resin particles.

  As an aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  As the resin to be used, styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and a polymer of a substituted product thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene copolymers such as lene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polychlorinated Vinyl, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, Aromatic petroleum resins, chlorinated paraffin, paraffin wax and the like can be mentioned, and these can be used alone or in combination.

  As a solvent that can be used for oil phase preparation, it is preferable that the boiling point is volatile with a temperature of less than 100 ° C. from the viewpoint of easy removal. Examples of the solvent include 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 amount of solvent used with respect to 100 parts of the toner composition is usually 10 to 900 parts.

  In the oil phase preparation, a colorant (or colorant masterbatch), a release agent, and a charge control agent, which are other toner compositions, are simultaneously added and mixed when forming a dispersion in an aqueous medium. However, it is more preferable to mix in advance in the oil phase.

  Further, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, and may be added after the particles are formed. Good. For example, after forming particles not containing a colorant, the colorant can be added by a known dyeing method.

  For the dispersion of the oil phase and the aqueous phase, all normal stirring mixers can be used, but more preferably, a homogenizer having a high-speed rotating body and a stator, a high-pressure homogenizer, a ball mill, a bead mill, and a sand mill. Etc. are 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. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. The emulsifier having rotating blades is not particularly limited, and any emulsifier and disperser that are generally commercially available can be used. For example, Ultra Thalax (manufactured by IKA), Polytron (manufactured by Kinematica), TK auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (manufactured by Ebara Corporation), TK pipeline homomixer , TK homomic line flow (manufactured by Special Machine Industries Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Chemical Co., Ltd.), Cavitron (Eurotech Co., Ltd.) ), Fine flow mill (manufactured by Taiheiyo Kiko Co., Ltd.), and other continuous emulsifiers, CLEARMIX (manufactured by M Technique Co., Ltd.), fill mix (manufactured by Koki Kogyo Co., Ltd.), etc. Etc.
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 10 to 98 ° C. The high temperature condition method is preferred in that the dispersion has a reasonably low viscosity and is easy to disperse.

  In the dissolution suspension method, a method of dispersing solid fine particles in an aqueous medium in advance is used for the purpose of stabilizing the dispersed oil phase.

  Furthermore, other dispersants can be used in combination to adjust the adsorptivity of the solid fine particle dispersant to the droplets. Other dispersants can be added before emulsification of the toner composition or after removal of volatile components after emulsification.

[Solid particulate dispersant]
The solid fine particle dispersant is a solid that is hardly soluble in water in an aqueous medium, and is preferably a fine particle having an average particle diameter of 0.01 to 1 μm.
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, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. More preferably, tricalcium phosphate, calcium carbonate, colloidal titanium oxide, colloidal silica, hydroxyapatite and the like can also be used. In particular, hydroxyapatite synthesized by reacting sodium phosphate and calcium chloride in water under a basic condition is preferable.
Examples of organic solid fine particle dispersants include microcrystals of low molecular weight organic compounds and polymer fine particles, such as polystyrene, methacrylate esters and acrylate ester copolymers obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization. Examples of the polymer particles include polycondensation systems such as silicone, benzoguanamine, and nylon, and thermosetting resins.

  In addition, when using a solid fine particle dispersant such as acid such as calcium phosphate or polymer fine particles copolymerized with (meth) acrylic acid having a carboxyl group, such as hydrochloric acid or sodium hydroxide. The solid fine particle dispersant is removed from the toner particles whose shape has been adjusted by, for example, washing with water after dissolving the solid fine particle dispersant with the acid / base. It can also be removed by operations such as enzymatic degradation.

[Other dispersants used together during emulsification or added later]
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, alkyltrimethylammonium salts, Nonionic interfaces such as dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, quaternary ammonium salt type cationic surfactants such as benzethonium chloride, fatty acid amide derivatives, polyhydric alcohol derivatives, etc. Activators include amphoteric surfactants such as alanine, dodecyl di (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine.

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, 31- [omega-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) 1-N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carboxylic acid and metal Salts, perfluoroalkylcarboxylic acids (C7 to C13) and their metal salts, perfluoroalkyl (C4 to C12) sulfonic acids and their metal salts, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2 hydroxyethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned,
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-1101 , DS-102, (Taikin Kogyo Co., Ltd.), Megafuck F-l0, F-l20, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF-ichi 102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fagento F-100, F150 (manufactured by Neos).

  Examples of the cationic surfactant include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6 1 C10) sulfonamidopropyltrimethylammonium salt, benza Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-21 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Megafac F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-32 (manufactured by Tochem Products), and Footgent F1300 (manufactured by Neos).

  The stabilization of the dispersed droplets may be adjusted with a polymer protective colloid. For example, (meth) acrylic monomer containing acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, or hydroxyl group For example, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloroacrylate 2-hydroxypropyl, 3-chloro-2-methacrylic acid methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, 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 esters of compounds containing vinyl alcohol and a carboxyl group 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, pinylviridine, vinylpyrrolidone, vinylimidazole, ethylene Homopolymers or copolymers such as those having a nitrogen atom such as imine or a heterocyclic ring thereof, polyoxyethylene, polyoxypropylene, Reoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl Polyoxyethylenes such as phenyl esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used. When a dispersant is used, the dispersant can remain on the surface of the toner particles, but it is preferable from the charged surface of the toner to wash away after the reaction.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer or rotary kiln.

  In the dissolution suspension method, solid particles usually adhere to the surface of emulsified oil droplets and stabilize the droplets in a spherical shape, but the volume of the droplets decreases while the volatile components are removed, but the solids The fine particles remain attached as they are, and the surface area of the droplets decreases slowly, and the sphere cannot be maintained without catching up with the decrease in volume, and may become amorphous.

  In the suspension solution method, to obtain a spherical toner with a high degree of circularity, when removing the toner volatile components, the adsorption force at the interface of the solid fine particles is weakened, detachment from the droplets is promoted, and the sphere is maintained. However, it is necessary to form particles. For example, by adding a surfactant or polymer protective colloid for exchange adsorption, or adjusting the pH in the aqueous medium to change the charge of the droplet surface and the solid particulate, adsorption at the solid particulate interface You can weaken your power.

(Sphericalizing of pulverized toner)
The toner by the pulverization / classification method is indefinite as it is, and depending on the pulverization method, the circularity is 0.930 to 0.950, and the circularity of the present invention is 0.96 to 1.00. However, the degree of circularity can be increased by a mechanical spheroidizing process or a heat treatment, which will be described later, and the toner having a circularity of 0.96 to 1.00 of the present invention can be obtained.

[Mechanical processing]
For example, a method using a turbo mill (manufactured by Turbo Kogyo) described in JP 09-087441 A, a kryptron (manufactured by Kawasaki Heavy Industries), a Q-type mixer (manufactured by Mitsui Mining), a hybridizer (manufactured by Nara Machinery), a mechanophy It is possible to spheroidize the shape of the pulverized toner by continuously processing with a fusion device (made by Hosokawa Micron etc.).

[Heat treatment (dry type)]
For example, the shape of the pulverized toner can be made spherical by semi-melting the toner particle surface with hot air of 100 to 300 ° C. using a surffusion system (Nippon Pneumatic Industry).

[Heat treatment (wet)]
The shape of the pulverized toner can be made spherical by immersing the toner obtained by the pulverization method in a high-temperature liquid at a temperature at which the toner has plasticity (about 200 ° C.).

(Description of charge control agent)
The toner used in the present invention may contain a charge control agent as necessary. Any known charge control agent can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine) Modified quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, metal salts of salicylic acid derivatives, and the like. Specifically, Nitronine dye Bontron 03, Quaternary ammonium salt Bontron P-51, Metal-containing azo dye Bontron S-34, Oxynaphthoic acid metal complex E-82, Salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (above, Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP 1415 (above, Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone Azo pigments, sulfonate group, a carboxyl group, a polymer compound having a functional group such as a quaternary ammonium salt.
When toner particles are produced in an aqueous medium, a charge control agent that is difficult to dissolve in water is preferable from the viewpoint of controlling ionic strength and wastewater contamination.

  In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably 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 main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents and mold release agents can be melt-kneaded together with the masterbatch and resin, and of course, they may be added when dissolved and dispersed in an organic solvent.

(Description about colorant)
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, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake , Thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo 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, Phthalo Cyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin.

  The toner colorant used in the present invention can also be used as a master batch combined with a resin. As the binder resin to be kneaded together with the production of the masterbatch or the masterbatch, in addition to the modified and unmodified polyester resins mentioned above, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and polymers of substituted products thereof; Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Tylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-malein Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. The

  This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. Also, a so-called flushing method called watering paste containing water of a colorant is mixed and kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

(Description of release agent)
Examples of the wax that can be used in the present invention include solid paraffin wax, microwax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, and partial kenne. Fatty acid ester wax, silicone varnish, higher alcohol, carnauba wax, and the like. Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. The wax has a melting point of 40 to 120 ° C., and preferably 50 to 110 ° C. When the melting point of the wax is excessive, the fixing property at low temperature may be insufficient. On the other hand, when the melting point is excessively low, the offset resistance and durability may be deteriorated. The melting point of the wax is determined by a differential scanning calorimetry ( DSC). That is, the melting peak value when a sample of several mg is ripened at a constant temperature increase rate, for example, (10 ° C./min) is defined as the melting point.

(Mixing of external additives)
In order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be added and mixed as an external additive to the toner produced as described above.
A general powder mixer is used for mixing the external additive, but it is preferable that a jacket or the like is provided to adjust the internal temperature. In order to change the load history applied to the external additive, the external additive may be added in the middle or gradually. Of course, you may change the rotation speed of a mixer, rolling speed, time, temperature, etc. A strong load may be given first, then a relatively weak load, and vice versa.
Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, and the like.

(Inorganic fine particles as external additives)
Inorganic fine particles can be used as an external additive for assisting the fluidity, developability, transferability, cleaning property, and chargeability of the toner. The primary particle diameter of the inorganic fine particles is preferably 0.01 to 2 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.1 to 15% by weight of the toner, and more preferably 0.5 to 10% by weight. 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, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

(Resin fine particles as external additives)
In the present invention, resin fine particles may be used together with the fluidizing agent of the present invention. For example, polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, methacrylic acid ester or acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine, nylon, polymer particles by thermosetting resin It is done. By using in combination with such resin fine particles, the chargeability of the toner can be enhanced, the reversely charged toner particles can be reduced, and the background contamination can be reduced. The addition amount may be 0.01 to 5% by weight, preferably 0.1 to 2% by weight, based on the toner.

Toner A (suspension polymerization method example, high circularity)
The toner A produced by the suspension polymerization method will be described.
Add 40 parts by weight of styrene monomer, 20 parts by weight of carbon black MA100 (manufactured by Mitsubishi Kasei Co., Ltd.) and 0.5 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator. Into a 500 ml four-necked separable flask equipped with a gas introduction tube and a thermometer, the mixture was stirred for 30 minutes at room temperature under a nitrogen stream, and the inside of the flask was replaced with nitrogen. Then, it stirred at 60 rpm in a 70 degreeC hot water bath for 6 hours, and graft carbon black was obtained. Then
Styrene monomer 50.0 parts by weight n-butyl methacrylate 14.5 parts by weight 1,3-butanediol dimethacrylate 0.5 parts by weight t-butylacrylamide sulfonic acid 3.0 parts by weight Low molecular weight polyethylene (Mitsui Petrochemical Co., Ltd. Mitsui High Wax 210P) 2.0 parts by weight A mixture of 30.0 parts by weight of the graft carbon black was dispersed with a ball mill for 10 hours. After dissolving 1 part by weight of 2,2'-azobisisobutyronitrile and sodium nitrite in this dispersion, each was added to 250 parts by weight of a 2% aqueous solution of polyvinyl alcohol, and added to a TK homomixer (specialized machinery company). The mixture was stirred at 6000 rpm for 10 minutes to obtain a suspension. Put the above suspension into a 500 ml four-necked separable flask equipped with a three-one motor-driven stirring blade, cooler, gas inlet tube, and thermometer, and stir at room temperature for 30 minutes under a nitrogen stream. Replaced with nitrogen. Thereafter, the mixture was stirred in a hot water bath at 70 ° C. for 8 hours at 90 rpm to complete the polymerization, thereby producing suspension polymerization particles. 100 parts by weight of these particles are redispersed in a mixed solution of water / methanol = 1/1 (weight ratio) so that the solid content is 30%, and 3 parts by weight of ditertiary butylsalicylic acid zinc salt is added as a charge control agent and stirred. Thereafter, filtration and drying were performed to obtain colored particles.
To 95 parts by weight of the obtained colored particles, 3 parts by weight of silica and 2 parts by weight of titanium oxide particles were mixed with a Henschel mixer for 2 minutes and sieved to obtain toner A.

The circularity of the toner A was 0.98.
The weight average particle diameter of the toner A was 5.81 μm.
To 95 parts by weight of a silicone-coated carrier (magnetite core material) having a weight average particle diameter of 50 μm, toner A was mixed by 5 parts by weight of a rocking mixer to obtain a two-component developer.

Toner D (Comparison example with pulverized toner, low circularity)
The toner D manufactured by the pulverization method will be described.
The following raw materials were sufficiently mixed with a Henschel mixer, and then kneaded with a small two-roll mill at 150 ° C. for 2 hours.
Binder resin (styrene-methyl acrylate copolymer) 100.0 parts by weight Colorant (carbon black # 44, manufactured by Mitsubishi Carbon Corporation) 10.0 parts by weight Charge control agent (ditertiary butylsalicylate zinc salt)
(Bontron E-84 manufactured by Orient Chemical Co., Ltd.) 2.0 parts by weight Carnauba wax 5.0 parts by weight The obtained kneaded product is roughly pulverized with a palverizer equipped with a 2 mm screen, then pulverized with a lab jet, and classified with 100 MZR. Thus, colored particles were obtained.
To 95 parts by weight of the obtained colored particles, 3 parts by weight of silica and 2 parts by weight of titanium oxide particles were mixed with a Henschel mixer for 2 minutes and sieved to obtain toner D.

The circularity of the toner D was 0.93.
Toner D had a weight average particle diameter of 5.73 μm.
To 95 parts by weight of a silicone-coated carrier (magnetite core material) having a weight average particle diameter of 50 μm, toner D was mixed with 5 parts by weight of a rocking mixer to obtain a two-component developer.

Toner G (Example of heat treatment of ground toner, high degree of circularity)
The colored particles obtained in the production example of Toner D are treated twice using a Nippon Pneumatic Surffusion System at a heat treatment temperature of 250 ° C., a hot air flow rate of 1000 l / min, and a supply air flow rate of 100 l / min to obtain colored particles. It was.
To 95 parts by weight of the obtained colored particles, 3 parts by weight of silica and 2 parts by weight of titanium oxide particles were mixed with a Henschel mixer for 2 minutes and sieved to obtain toner G.

The circularity of the toner G was 0.97.
The weight average particle size of the toner G was 5.56 μm.
To 95 parts by weight of a silicone-coated carrier (magnetite core material) having a weight average particle diameter of 50 μm, toner G was mixed with 5 parts by weight of a rocking mixer to obtain a two-component developer.

  The circularity of each toner used is 0.98 for toner A, 0.93 for toner D, and 0.97 for toner G. When these toners were used and the change with time was examined, the rising of the charge of the toner D after a lapse of a predetermined time was slow and the scattering amount was larger than the initial value, which was 32 [mg / min]. It is considered that because of the amorphous shape, the dispersion efficiency of the additive is poor and the uniformity of charging cannot be obtained. On the other hand, the scattering amounts of toners A and G after a predetermined time were 15 [mg / min] and 19 [mg / min], respectively.

  A second embodiment of the present invention will be described with reference to FIGS. In addition, the same part as the part demonstrated in FIG. 1 thru | or FIG. 9 is shown with the same code | symbol, and description is also abbreviate | omitted.

  FIG. 10 is a longitudinal side view showing a schematic configuration of the developing device 5. In the present embodiment, each developing device 5 is provided with a developer suction mechanism 50 that is a removing means instead of the air blowing mechanism 35 that is the removing means described in the first embodiment. The developer suction mechanism 50 includes a powder pump 51, a suction pipe 52 having one end connected to the powder pump 51 and the other end connected to the developer container 28, and a bottom surface in the developer container 28. Are transported toward the connecting portion of the suction pipe 52, a screw cover 54 that covers the top of the transport screw 53, and the like. As shown in FIG. 11, one end of a link 55 that rotates by a predetermined angle as the developer layer thickness regulating roller 32 rotates is attached to the rotation shaft of the developer layer thickness regulating roller 32, and the other end side of the link 55 A screw cover 54 is swingably attached.

  FIG. 11 shows a state in which the toner image is developed on the photosensitive belt 2 by the developing roller 29 rotating in the direction of arrow C. At this time, the developer layer thickness regulating roller 32 is stopped without being rotated by the bearing using the one-way clutch. As the developing operation continues, the toner aggregates in the wedge-shaped portion on the upstream side in the rotation direction of the developing roller 29 in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other. Toner 40 may be generated. When such agglomerated toner 40 is generated, it becomes difficult for the toner to be rubbed between the developing roller 29 and the developer layer thickness regulating roller 32, so that the charging ability is lowered and the image density is lowered. Further, when the aggregated toner 40 is generated, the gap between the developing roller 29 and the developer layer thickness regulating roller 32 becomes large, and the amount of toner that rubs between the developing roller 29 and the developer layer thickness regulating roller 32 is increased. Increases and soiling occurs.

  In FIG. 12, in order to remove the aggregation toner 40, the developing roller 29 is rotated in the direction of arrow C ′ after the completion of the developing operation, and the developer layer thickness regulating roller 32 is rotated in the direction of arrow D. A state in which the suction mechanism 50 is driven is shown. When the developer suction mechanism 50 is driven, the conveying screw 53 rotates and the powder pump 51 performs a suction operation.

First, the developing roller 29 rotates in the direction of the arrow C ′, and the developer layer thickness regulating roller 32 rotates in the direction of the arrow D, whereby the aggregated toner 40 is separated between the developing roller 29 and the developer layer thickness regulating roller 32. It is pushed back in the direction shown by the arrow E from the wedge-shaped part in between.
Further, when the developer layer thickness regulating roller 32 rotates in the direction of arrow D, the link 55 rotates by a predetermined angle in the direction indicated by arrow G, and the screw cover 54 moves in the direction of arrow H with the connection point with the link 55 as a fulcrum. To turn.
As a result, the agglomerated toner 40 extruded in the direction of arrow E slides down toward the conveying screw 53 along the upper surface of the scraper 34 and is conveyed toward the opening of the suction pipe 52 by the conveying screw 53.
Aggregated toner 40 conveyed to the opening of suction pipe 52 by conveyance screw 53 is sucked by powder pump 51 through suction pipe 52. Thereby, when the developing operation is restarted, it is possible to prevent a decrease in image density and a background stain caused by the aggregated toner 40.

  The agglomerated toner 40 sucked by the powder pump 51 is loosened in the suction process, returned to the developing container 28 from the discharge side of the powder pump 51, mixed with the toner in the developing container 28, and recycled. used. Thereby, the aggregated toner 40 once aggregated can be effectively reused without being wasted.

FIG. 13 is a block diagram showing the electrical connection of each unit provided in the color printer 1.
The color printer 1 includes a controller 41 for controlling each unit. The controller 41 centrally controls each unit (CPU) 42, and various programs executed by the CPU 42 are stored in a ROM ( A read only memory (RAM) 43, a RAM (Random Access Memory) 44 that functions as a work area for the CPU 42, and the like are connected by a bus line 45.

  Further, the CPU 42 includes a powder pump 51 via a pump controller 51a, a motor 56 for driving a conveying screw 53 connected via a motor controller 56a, and toner of a toner image formed on the photosensitive belt 2. A density sensor 46 that detects the density and a remaining amount sensor 47 that detects the remaining amount of toner in the developing device 5 are connected.

  FIG. 14 is a flowchart illustrating the timing for driving the developer suction mechanism 50. The controller 41 determines whether or not one print output job is completed (step S31), and drives the developer suction mechanism 50 after one job is completed (step S2). One job of print output ends when the emission of laser light based on the optical writing signal input to the optical writing device 4 ends. Therefore, since the developer suction mechanism 50 is driven every time one job is completed, the generation of the aggregated toner 40 can be prevented in advance, or it can be removed at an early stage before the aggregated toner 40 becomes large. it can. Accordingly, it is possible to prevent the density unevenness and background stain of the image caused by the aggregation toner 40 and to improve the quality of the formed image. In addition, since the developer suction mechanism 50 is driven immediately after one job is completed, there is no inconvenience that the work efficiency of the image forming operation is lowered even if the developer suction mechanism 50 is driven.

  FIG. 15 is a flowchart for explaining another timing at which the developer suction mechanism 50 is driven. At a preset timing, a patch for density detection is formed on the photosensitive belt 2 under the control of the controller 41 (step S41), and the toner density of the patch is detected by the density sensor 46 (step S42). Then, it is determined whether or not the detected toner density is equal to or lower than the set value (step S43). If the detected toner density is equal to or lower than the set value, the developer suction mechanism 50 is driven (step S44). As a result, the agglomerated toner 40 generated in the wedge-shaped portion on the upstream side in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other along the rotation direction of the developing roller 29 is sucked. It is possible to eliminate the uneven density of the image and the background stain caused by the aggregation toner 40, and the quality of the formed image can be improved.

  FIG. 16 is a flowchart for explaining another timing at which the developer suction mechanism 50 is driven. Based on the detection result of the remaining amount sensor 47, the controller 41 determines whether or not the remaining amount of toner in the developing device 5 has become a set value or less (step S51). In step S52, the developer suction mechanism 50 is driven. As a result, when the remaining amount of toner in the developing device 5 decreases, the fluidity of the toner in the developing device 5 decreases, and in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other, the developing roller The aggregated toner 40 is likely to be generated in the wedge-shaped portion on the upstream side along the rotation direction 29, but the generation of the aggregated toner 40 can be prevented in advance, or the aggregated toner 40 is removed at a small stage. Can do. Accordingly, it is possible to prevent the density unevenness and background stain of the image caused by the aggregation toner 40 and to improve the quality of the formed image.

  A third embodiment of the present invention will be described with reference to FIG. The process cartridge 60 according to the present embodiment includes a cartridge case 61, a drum-shaped photosensitive member 62 that is an image carrier housed in the cartridge case 61, a charging device 63, a developing device 64, a cleaning device 65, and the like. ing. When the process cartridge 60 is mounted in the image forming apparatus and the image forming operation is started, the photosensitive member 62 is rotated around the center line by a drive motor in the image forming apparatus, and the outer peripheral surface of the rotating photosensitive member 62 is charged by the charging device. The electrostatic latent image is formed by irradiating laser light emitted from an optical writing device (not shown) to the outer peripheral surface of the uniformly charged photoreceptor 62 by the laser beam The electrostatic latent image is developed with the toner supplied from the developing device 64 to form a toner image. The toner image formed on the photoreceptor 62 is transferred to the recording medium P by being pressed against the recording medium P transported by the photoreceptor 62 at a portion exposed from the opening 66 of the cartridge case 61 in the photoreceptor 62. Is done. The toner remaining on the photoconductor 62 after the toner image is transferred to the recording medium P is removed and collected by the cleaning device 65 as waste toner.

  The basic structure of the developing device 64 is the same as that of the developing device 5 described in the first embodiment, and includes a developing roller 29, a developer layer thickness regulating roller 32, an air blowing mechanism 35, and the like.

  Here, in the developing device 64, as in the developing device 5 described in the first embodiment, the developing roller 29 is in the vicinity of the position where the developing roller 29 and the developer layer thickness regulating roller 32 face each other. Aggregated toner in which the developer is aggregated is likely to be generated in the wedge-shaped portion at the upstream position along the rotation direction. It is possible to prevent image density unevenness and background smearing caused by the generation of aggregated toner, and to improve the quality of the formed image.

  In the process cartridge 60 of the present embodiment, the case where the developing device 64 has the air blowing mechanism 35 has been described as an example. However, the developer described in the second embodiment instead of the air blowing mechanism 35 is described. A developing device having the suction mechanism 50 may be used. In this case as well, it is possible to prevent unevenness in image density and background stains caused by the generation of aggregated toner, and to improve the quality of the formed image. Can do.

1 is a longitudinal side view showing a schematic configuration of a color printer according to a first embodiment of the present invention. It is a vertical side view which shows schematic structure of a developing device. FIG. 3 is a longitudinal side view illustrating a part of the developing device when a toner image is formed on a photosensitive belt. FIG. 6 is a longitudinal side view showing a part of the developing device when a developing roller and a developer layer thickness regulating roller are rotated in order to remove agglomerated toner. It is a vertical side view showing a part of the developing device when the air blowing mechanism is driven to remove the agglomerated toner. FIG. 3 is a block diagram illustrating electrical connections of respective units included in the color printer. It is a flowchart explaining the timing which drives an air blowing mechanism. It is a flowchart explaining another timing which drives an air blowing mechanism. It is a flowchart explaining another timing which drives an air blowing mechanism. It is a vertical side view which shows schematic structure of the image development apparatus of the 2nd Embodiment of this invention. FIG. 3 is a longitudinal side view illustrating a part of the developing device when a toner image is formed on a photosensitive belt. FIG. 5 is a longitudinal side view showing a part of the developing device when a developing roller and a developer layer thickness regulating roller are rotated and a developer suction mechanism is driven to remove agglomerated toner. FIG. 3 is a block diagram illustrating electrical connections of respective units included in the color printer. 6 is a flowchart illustrating timing for driving a developer suction mechanism. 10 is a flowchart illustrating another timing for driving the developer suction mechanism. 10 is a flowchart illustrating another timing for driving the developer suction mechanism. It is a vertical side view which shows the process cartridge of the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image carrier 3 Charging apparatus 4 Optical writing apparatus 5 Developing apparatus 6 Transfer apparatus 12 Fixing apparatus 29 Developing roller 32 Developer layer thickness regulating member 35 Removing means, air blowing mechanism 46 Concentration sensor 47 Remaining sensor 50 Removal means, developer suction mechanism 60 Process cartridge 61 Cartridge case 62 Image carrier 64 Developing device

Claims (10)

A developing roller which carries a developer and is rotatable about a center line for supplying the carried developer to an image carrier on which an electrostatic latent image is formed;
A developer layer thickness regulating member that is disposed to face the outer peripheral surface of the developing roller and regulates the layer thickness of the developer carried by the developing roller;
Removing means for removing the developer aggregated at a position in the vicinity of the facing position between the developing roller and the developer layer thickness regulating member and upstream in the rotation direction of the developing roller;
A developing device comprising:   The removal means is an air blowing mechanism that blows air to a position in the vicinity of a position where the developing roller and the developer layer thickness regulating member face each other and upstream in the rotation direction of the developing roller. The developing device according to 1.   The removing means is a developer suction mechanism that sucks a developer that is located in the vicinity of a position where the developing roller and the developer layer thickness regulating member face each other and upstream in the rotation direction of the developing roller. The developing device according to claim 1.   The developing device according to claim 1, wherein the toner occupying at least a part of the developer has a circularity of 0.9 or more. An image carrier;
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 any one of claims 1 to 4, wherein a toner image is formed by developing an electrostatic latent image written on an outer peripheral surface of the image carrier;
A transfer device for transferring the developed toner image to a recording medium;
A fixing device for fixing the toner image transferred to the recording medium;
An image forming apparatus comprising:   6. The image forming apparatus according to claim 5, comprising a plurality of the developing devices arranged in a tandem type.   5. The image forming apparatus according to claim 5, further comprising means for driving the air blowing mechanism or the developer suction mechanism immediately after one print output job for transferring a toner image to the recording medium is completed.   7. A density sensor for detecting a toner density of a toner image on the image carrier, and means for driving the air blowing mechanism or the developer suction mechanism according to a detection result by the density sensor. Image forming apparatus.   7. A remaining amount sensor for detecting a remaining amount of developer in the developing device, and means for driving the air blowing mechanism or the developer suction mechanism in accordance with a detection result by the remaining amount sensor. The image forming apparatus described. An image carrier;
A cartridge case for rotatably holding the image carrier;
The developing device according to any one of claims 1 to 4, housed in the cartridge case;
A process cartridge comprising:

Images