JP4890365B2 - Developing device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device that performs development using a two-component developer composed of toner and a carrier, a process cartridge that includes the developing device, and an image that uses the developing device or the process cartridge and uses an electrophotographic method. The present invention relates to an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a complex machine of these. The present invention further relates to an image forming apparatus including a plurality of the developing devices or the process cartridges and capable of color image formation.

  2. Description of the Related Art Conventionally, as a biaxial transport type developing device that performs development using a two-component developer, developer supply to a developer carrier (developing roller) and developer transport member (screw, auger, etc.) and supply for collection A collection conveyance path, a developer conveyance member for conveyance agitation after toner replenishment, and an agitation conveyance path are configured, and these are arranged in a substantially horizontal direction below the developer carrier. .

  In such a biaxial transport type developing device, the developer in the developing device spatially varies in toner density due to toner replenishment and toner consumption due to development. Therefore, conventionally, the fluctuation of the toner density has been reduced by diffusing the developer with the developer conveying member. For example, according to the prior art described in Patent Document 1 (Japanese Patent Application Laid-Open No. 7-114209), a developer is conveyed by providing a speed difference to each screw or by making the shape of the screw notch into an elliptical plate shape. A technique for increasing the diffusion capacity of a member is disclosed. However, even if these techniques are used, the developer cannot be sufficiently diffused by the time it reaches the developer carrier, and the toner density fluctuation remains in the developer pumped up by the developer carrier. Is the current situation.

JP 7-114209 A

  As described above, in a conventional developing device having a two-axis conveyance configuration, the toner density fluctuation formed on the screw due to toner replenishment and consumption is intended to be reduced only by the diffusion effect by the developer conveying member. However, in this method, the wavelength does not change in the waveform of the toner density fluctuation, and only the amplitude is reduced. Therefore, in order to sufficiently reduce the toner density fluctuation, the developer needs to go around the developing device many times. there were.

  The present invention has been made in view of the above circumstances, and by controlling the phase of the toner density fluctuation, the toner density can be instantaneously uniformed, and the toner density before the developer is pumped up to the developer carrier. It is an object of the present invention to provide a developing device having a configuration capable of sufficiently suppressing the fluctuation of the toner and the variation of the toner charge amount, and a process cartridge and an image forming apparatus provided with the developing device.

As means for achieving the above object, the present invention employs the following technical means.
The first means of the present invention includes a developer carrying member for carrying a two-component developer composed of toner and carrier in the developing device, and a developer that conveys the developer in the axial direction opposite to the developer carrying member. And a developing device that develops and visualizes the latent image on the latent image carrier with the toner of the two-component developer, and calculates an average time required for the developer to make one revolution in the developing unit. [S], where the toner replenishment cycle to the developing unit is t [s], the replenishment cycle t is smaller than the average time T, and the average time T and the replenishment cycle t are the following formulas (1) ) Is satisfied.
(1/4 + n) .t <T <(3/4 + n) .t Formula (1)
(N = 0, 1, 2, ...)

According to a second means of the present invention, when the developing device of the first means has a plurality of image forming modes and the replenishment cycle t changes in accordance with the image forming mode, the above formula ( It is characterized in that the relationship 1) holds.
According to a third means of the present invention, in the developing device of the first means, there are a plurality of image forming modes, and when the replenishment cycle t changes according to the image forming mode, the largest t is It is characterized in that the relationship of the formula (1) is established.
Furthermore, a fourth means of the present invention is the developing device of any one of the first to third means, wherein there are a plurality of image forming modes, and when the replenishment cycle t changes according to the image forming mode, And a mechanism for changing the average time T.

A fifth means of the present invention is characterized in that, in the developing device of the fourth means, the average time T is changed by changing the number of rotations of the developer conveying member.
The sixth means of the present invention is characterized in that, in the developing device of any one of the first to fifth means, the replenishment cycle t is changed in accordance with a change with time of the average time T. .
Further, the seventh means of the present invention is the developing device of any one of the first to sixth means, wherein the developer after development is collected from the developer carrying member and the collected developer is supplied for development. And a recovery developer transport member that transports in parallel and in the same direction as the developer transport member.

  The eighth means of the present invention includes at least a latent image carrier on which an electrostatic latent image is formed, and an electrostatic latent image on the latent image carrier using a two-component developer comprising a toner and a carrier. And a developing device that develops and visualizes the toner, the developing device includes a developing device of any one of first to seventh means as the developing device.

  The ninth means of the present invention comprises at least a latent image carrier on which an electrostatic latent image is formed and a two-component developer comprising a toner and a carrier and the electrostatic latent image on the latent image carrier. An image forming apparatus comprising: a developing device that develops and visualizes a developing device, comprising a developing device of any one of the first to seventh means, or a process cartridge of the eighth means. .

A tenth means of the present invention is the image forming apparatus of the ninth means, comprising a plurality of developing devices or process cartridges having different developing colors, and forming a color image on a recording material.
The eleventh means of the present invention is the image forming apparatus of the ninth means, comprising at least a latent image carrier and a developing device for developing the electrostatic latent image formed on the latent image carrier. Equipped with multiple units or process cartridges, each image forming unit or each process cartridge forms an image with a different development color and transfers it directly to the recording material or via an intermediate transfer member to form a color image on the recording material It is characterized by doing.

  The developer in the developing device spatially varies in toner density due to toner replenishment and toner consumption (development). Conventionally, the fluctuation of the toner density has been reduced by diffusing the developer with a developer conveying member such as a screw. In order to increase the diffusion capacity of the screw, the screw shape can be devised by increasing the number of rotations of the screw or attaching fins, but there are also limitations, and the developer is a developer carrier (for example, developing on the developing roller). In the present situation, the toner density fluctuations still remain in the developer pumped up by the developing sleeve because the toner cannot be sufficiently diffused until it reaches the sleeve.

Therefore, in the developing device of the first means of the present invention, the relationship between the average time T required for the developer to make one revolution in the developing device and the toner replenishment cycle t to the developing device is expressed by the above-mentioned formula (1). By adjusting so as to satisfy, it is possible to shift the phase of the toner density fluctuation in the previous circumference and the toner density fluctuation that can be performed by toner replenishment from the next circumference (the toner density that has remained unstirred in the previous circumference) Toner can be replenished in the valley of the fluctuation amplitude).
In this manner, by supplying toner with a phase shift to a developer whose toner density varies spatially, the high and low toner densities are averaged and the toner density is made uniform. The toner diffusion effect obtained by superimposing the phases out of phase is significantly greater than the effect obtained by stirring with a developer conveying member such as a screw.
As a result, the toner density fluctuation of the developer pumped up on the developing sleeve is reduced to a negligible level, and accordingly, the charging is made more uniform.

By the way, when toner is replenished at an image output cycle, the replenishment cycle t changes according to the size of the paper to be output.
When there are a plurality of replenishment cycles t as described above, there is a possibility that even if the phase shifts at a certain t, the phases may overlap at a certain t.
Therefore, in the developing device of the second means, the phase can be shifted regardless of the supply cycle t by setting T so as to satisfy the relationship of the above formula (1) for all supply cycles t. , Toner density fluctuations can be suppressed.

Next, the toner density fluctuation in the developing device is less diffused as the wavelength is longer.
Accordingly, in the developing device of the third means, when there are a plurality of toner replenishment cycles t, at least the largest t (the largest toner density fluctuation wavelength that can be produced by this replenishment) satisfies the relationship of the above-mentioned formula (1). By setting T, it is possible to suppress the amplitude of long-wavelength toner density fluctuations that are difficult to diffuse.

Next, it is desired to always satisfy the relationship of the above formula (1) even in the modes with different replenishment cycles t.
Therefore, in the developing device of the fourth means, the relationship of the above formula (1) can always be satisfied by changing T in accordance with the change of the replenishment cycle t.
Further, in the developing device of the fifth means, T is also changed by changing the rotation speed of the developer conveying member such as a screw in accordance with the change of the replenishment cycle t. Therefore, the relationship of the above formula (1) is always satisfied. Can be satisfied.

The developer deteriorates with time, and the developer transport efficiency on the screw changes. Therefore, even if the relationship of the above formula (1) is satisfied in the initial agent state, there is a high possibility that it will not be satisfied over time.
Therefore, in the developing device of the sixth means, by setting the replenishment cycle t according to the change of T, the phase can be always stably shifted, and the toner density fluctuation can be suppressed.

  In the developing device of the seventh means, a developer transport member for recovery (for example, a recovery transport screw) is provided and a one-way circulation configuration is adopted, so that all the developed developer is recovered by the recovery transport screw and supplied and transported. Therefore, the toner density fluctuation due to consumption of the developing toner does not occur on the supply screw. Therefore, the toner density fluctuation is caused only by the replenishment of toner, and the phase control means of the present invention makes it possible to more accurately control the phase and supply a developer having a uniform toner density to the development.

In the process cartridge of the eighth means of the present invention, since the developing device of any one of the first to seventh means is provided as the developing device, a stable toner adhesion amount can be obtained for a long period of time. Therefore, it is possible to provide a process cartridge having high image density stability.
In the image forming apparatus of the ninth means of the present invention, since the developing device of any one of the first to seventh means or the process cartridge of the eighth means is provided, it is always stable over a long period of time. Therefore, it is possible to provide an image forming apparatus which can obtain a stable image quality with little fluctuation in image density over a long period of time and no scumming or toner scattering.

  The image forming apparatus of the tenth means of the present invention comprises a plurality of developing devices or process cartridges having different developing colors, and forms a color image on a recording material. By using the developing device of any one of the above, it is possible to always obtain a stable toner adhesion amount over a long period of time, so that the image density is highly stable, and high-quality color with excellent color reproducibility and color balance. An image forming apparatus capable of obtaining an image can be provided.

  The eleventh image forming apparatus of the present invention comprises a plurality of image forming units or process cartridges each having at least a latent image carrier and a developing device for developing an electrostatic latent image formed on the latent image carrier. Each image forming unit or process is characterized by forming images of different development colors with a forming unit or process cartridge and transferring them to a recording material directly or via an intermediate transfer member to form a color image on the recording material. By using the developing device of any one of the first to seventh means as the developing device of the cartridge, it is possible to always obtain a stable toner adhesion amount over a long period of time. In addition, it is possible to provide a small-sized and low-cost color image forming apparatus that can obtain stable image quality without toner scattering.

  Hereinafter, specific configurations, operations, and effects of the present invention will be described in detail based on illustrated embodiments.

[Description of phase control]
FIG. 1 is an explanatory diagram of developer circulation paths and toner density fluctuations of a biaxial transport type developing device according to the present invention. Hereinafter, description will be made by taking the biaxial conveyance type developing device shown in FIG. 1 as an example.
In the developing device in which toner is consumed in the developing unit according to the image and intermittent toner replenishment is performed in the toner replenishing unit, the two developer conveying members (stirring conveying screw 5c and supply conveying screw 5b) In the longitudinal direction, periodic fluctuations in toner density are observed. Here, a portion where the toner density is high is plotted with a dotted line.

The wavelength λ [m] of the fluctuation is determined by the toner replenishment cycle T1 [s], the toner consumption cycle (image output cycle) T2 [s], and the developer conveyance speed u [m / s] on the conveyance screw.
The wavelength of variation created by toner replenishment is
λ1 = u · T1
And the wavelength of variation created by toner consumption is
λ2 = u · T2
It is.

Although there are two different variations of wavelength, in many developing devices, the amplitude of the variation that can be made on the conveying screw by toner replenishment is larger than the variation that can be made on the conveying screw by toner consumption.
λ ≒ λ1
Can be approximated. That is, the change in toner density may be mainly considered due to toner replenishment. That is, this is a change in toner density that occurs in the replenishment toner cycle.

When the wave of wavelength λ moves in the developing device of the developing device while being stirred by the stirring and conveying screw 5c and the supply and conveying screw 5b, the wavelength does not change and only the amplitude is reduced. The time T [s] required for the developer to make one revolution in the developing device can be measured as follows, for example.
As shown in FIG. 5A, the toner concentration sensor 5S is disposed on the stirring and conveying screw 5c in the developing device of the developing device. Then, the toner is replenished once from the toner replenishing port, and T is measured from the time Δt between the measured values of the toner density sensor 5S as shown in FIG. 5B. Since T varies depending on the height of the agent surface, the magnetic force arrangement in the developing sleeve, the toner density, and the like, it must be measured under the same conditions as the actual image forming conditions.

  FIG. 2 shows a developer circulation path and a toner concentration distribution of the developer at a certain time in the conventional biaxial stirring method. This is a distribution when toner is replenished every 2 [s]. As the agitation distance increases, the amplitude of the toner density fluctuation gradually decreases, but at a position close to the developing sleeve, such as point C or point D, the amplitude of the toner density fluctuation is still large, and a developer having a high toner density is present. Contamination and toner scattering occur due to being conveyed to the development area. In particular, toner scattering and scumming are likely to occur on the upstream side of the developing sleeve (near point C). Therefore, it becomes a problem to suppress the toner density fluctuation before the point C is reached.

Therefore, it is considered that the toner density is replenished so as to be different from the phase of the toner density fluctuation wave generated by toner replenishment on the previous circumference, and the amplitude of the toner density fluctuation is reduced by superimposing the two waves. This is called a phase control mechanism.
In order to reduce the amplitude by superimposing different toner density fluctuations, it is most effective when the phase difference is π. FIG. 3 shows how the toner density fluctuates at this time.

[Description of toner supply conditions]
Here, the effect of phase control by toner replenishment will be described. FIG. 4 shows the relationship between the time T required for the developer to go around the developing device, the toner replenishment cycle t, and the toner density fluctuation. Note that the toner density fluctuation caused by toner replenishment is indicated by a one-dot chain line, and the toner density fluctuation remaining even after one round of the developing device is indicated by a dotted line. When T = nt in FIG. 4 (1), the two toner density fluctuations are not out of phase, so the effect of reducing the toner density fluctuation is not obtained, but T = (n + 1/2) in FIG. 4 (2). ) At t, the phase is shifted by π, so the reduction effect is the highest. The phase difference between the two toner density fluctuations is preferably in the range of π ± (1/4) π, and most preferably when the phase difference is π. Therefore, the time T required for the developer to go around the developing device is
(1/4 + n) .t <T <(3/4 + n) .t Formula (1)
In the range of
T = (1/2 + n) · t
Is most desirable. Here, n = 1, 2, 3,.
In this embodiment, T = 9 [s] is set for the toner replenishment cycle t = 2 [s].

[Description of overall image forming apparatus and configuration of image forming unit including developing device]
FIG. 6 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention. Here, an embodiment applied to an electrophotographic image forming apparatus will be described.
The image forming apparatus includes yellow (hereinafter referred to as “Y”), cyan (hereinafter referred to as “C”), magenta (hereinafter referred to as “M”), and black (hereinafter referred to as “K”). A four-color toner is used to form a multicolor or color image.

  First, a basic configuration of the image forming apparatus will be described. The image forming apparatus includes four photoconductors 1Y, 1C, 1M, and 1K as image carriers in a color image forming unit 30. Although a drum-shaped photoconductor is taken as an example here, a belt-shaped photoconductor can also be adopted. The photoconductors 1Y, 1C, 1M, and 1K are arranged in parallel along an intermediate transfer belt 10 as an intermediate transfer body, and are driven to rotate in the direction of the arrow in the drawing while being in contact with the intermediate transfer belt 10. . Each of the photoreceptors 1Y, 1C, 1M, and 1K is obtained by forming a photoconductive photosensitive layer on a relatively thin cylindrical conductive substrate and further forming a protective layer on the photosensitive layer. Further, an intermediate layer may be provided between the photosensitive layer and the protective layer. The outer diameter of the photoconductor of this example is 30 mm.

  FIG. 7 is a schematic diagram showing a configuration around one of the four photoconductors 1Y, 1C, 1M, and 1K, and shows a configuration of one image forming unit (image forming unit for each color). ing. Since the configuration around each of the photoconductors 1Y, 1C, 1M, and 1K is the same, only the configuration of one image forming unit (image forming unit) is illustrated, and reference symbols Y, C, M, and K for color coding are shown. Is omitted.

  Around the photoreceptor 1 of each color image forming unit, a cleaning device 7 that removes transfer residual toner from the photoreceptor, a charging device 3 as a charging unit, and a developing device 5 as a developing unit are arranged in this order. Here, the charging device 3, the developing device 5, the cleaning device 7 and the photosensitive member 1 of the image forming unit shown in FIG. 7 are integrally formed in a cartridge (not shown) to form a process cartridge. The process cartridge is configured to be detachable from the main body of the image forming apparatus and can be replaced. That is, the image forming apparatus shown in FIG. 6 has a configuration in which four process cartridges are detachably arranged in parallel along the intermediate transfer belt 10.

  Further, a space is provided between the charging device 3 and the developing device 5 of the image forming unit (process cartridge) shown in FIG. 7 so that light emitted from the exposure device 4 as a latent image forming unit can pass to the photosensitive member 1. Is secured.

  The charging device 3 is arranged such that a rotatable roller-shaped charging member 3a is disposed close to the photosensitive member 1, and a voltage obtained by superimposing a direct current on an alternating current is applied to the charging member 3a from the outside. The photosensitive member 1 is charged by discharging between them. In the present embodiment, the charged potential of the photoreceptor 1 is −500V. Alternatively, the photoreceptor 1 may be charged using a contact charging roller with which the charging member 30a is in contact.

  Light is exposed by the exposure device 4 on the surface of the photoreceptor 1 charged in this way, and an electrostatic latent image corresponding to each color is formed. The exposure device 4 writes an electrostatic latent image corresponding to each color on the photoreceptor 1 based on image information corresponding to each color. The exposure apparatus 4 of the present embodiment is a laser scanning type exposure apparatus comprising a plurality of semiconductor laser light sources, optical deflectors, scanning imaging optical systems, etc., but is an exposure apparatus comprising an LED array and imaging means. It is also possible to employ other types of exposure apparatuses such as those described above.

  The developing device 5 is a two-axis conveying type developing device, and includes a developing roller 5a that is a developer carrying member that carries a developer, an agitating and conveying screw 5c that is an agitating and conveying member that agitates and conveys the developer, and a developer. It consists of the supply conveyance screw 5b which is a supply conveyance member. The stirring and conveying screw 5c and the supply and conveying screw 5b are separated from each other by the partition plate 5d. The developing roller 5a as the developer carrying member is partially exposed from the opening of the casing. Here, a two-component developer composed of toner and carrier is used.

  The developing device 5 receives toner of the corresponding color from the toner bottles 31Y, 31C, 31M, and 31K shown in FIG. The toner bottles 31Y, 31C, 31M, and 31K are configured to be detachable from the main body of the image forming apparatus so that they can be replaced individually. With such a configuration, only the toner bottles 31Y, 31C, 31M, and 31K may be replaced at the time of toner end. Therefore, other components that have not yet reached the end of their life when the toner ends can be used as they are, and the user's expense can be reduced.

  The toner replenished into the developing device 5 from the toner bottles 31Y, 31C, 31M, and 31K is conveyed to the supply conveyance screw 5b while being agitated with the developer by the agitation conveyance screw 5c, and is carried on the developing roller 5a there. It will be. The developing roller 5a is composed of a magnet roller (or a plurality of fixed magnets) magnetized with a plurality of magnetic poles as magnetic field generating means fixed inside, and a developing sleeve that rotates coaxially therearound. The developer in the supply / conveyance screw section (supply / conveyance path) is pumped up on the development roller by the magnetic force generated by the magnet roller, and after being thinned by the developer regulating member 5e, the developer stands on the development roller 5a. Then, it is conveyed to the developing area facing the photosensitive member 1.

  Here, the developing roller 5 a moves in the same direction at a linear velocity faster than the surface of the photosensitive member 1 in a region facing the photosensitive member 1 (hereinafter referred to as “developing region”). Then, the carrier spiked on the developing roller 5 a supplies the toner adhering to the carrier surface to the surface of the photoreceptor 1 while rubbing the surface of the photoreceptor 1. At this time, a developing bias VB of −350 V is applied to the developing roller 5a from a power source (not shown), thereby forming a developing electric field in the developing region. Then, between the electrostatic latent image on the photoreceptor 1 and the developing roller 5a, an electrostatic force directed toward the electrostatic latent image side acts on the toner on the developing roller 5a. As a result, the toner on the developing roller 5 a is electrostatically attached to the electrostatic latent image on the photoreceptor 1. By this adhesion, the electrostatic latent image on the photoreceptor 1 is developed (developed) into a toner image of a corresponding color.

  The intermediate transfer belt 10 in the transfer device 6 is stretched around three support rollers 11, 12, and 13 and is configured to endlessly move in the direction of the arrow in the drawing. On the intermediate transfer belt 10, toner images on the photoreceptors 1Y, 1C, 1M, and 1K are transferred so as to overlap each other by an electrostatic transfer method. Although there is a configuration using a transfer charger in the electrostatic transfer system, a configuration using a transfer roller that generates little transfer dust is adopted here. Specifically, primary transfer rollers 14Y, 14C, 14M, and 14K as transfer devices 6 are disposed on the back surface of the portion of the intermediate transfer belt 10 that contacts the photoreceptors 1Y, 1C, 1M, and 1K, respectively. Here, a primary transfer nip portion is formed by the portions of the intermediate transfer belt 10 pressed by the primary transfer rollers 14Y, 14C, 14M, and 14K and the photoreceptors 1Y, 1C, 1M, and 1K. When transferring the toner images on the photoreceptors 1Y, 1C, 1M, and 1K onto the intermediate transfer belt 10, a positive bias is applied to each primary transfer roller. As a result, a transfer electric field is formed in each primary transfer nip portion, and the toner images on the photoreceptors 1Y, 1C, 1M, and 1K are electrostatically attached to the intermediate transfer belt 10 and transferred.

  Untransferred toner remaining on the photoreceptor without being transferred by the transfer device 6 is collected by the cleaning device 7 and sent to a waste toner collecting bottle (not shown). Here, in the cleaning device 7, a rubber cleaning blade is in contact with the photoreceptor 1, and the transfer residual toner is removed from the photoreceptor 1. In addition to the blade, cleaning with a fur brush or the like may be performed.

  A belt cleaning device 15 for removing toner remaining on the surface of the intermediate transfer belt 10 is provided around the intermediate transfer belt 10. The belt cleaning device 15 is configured to collect unnecessary toner adhering to the surface of the intermediate transfer belt 10 with a fur brush and a cleaning blade. The collected unnecessary toner is transported from the belt cleaning device 15 to a waste toner tank (not shown) by a transport means (not shown).

  Further, a secondary transfer roller 16 is disposed in contact with the portion of the intermediate transfer belt 10 stretched around the support roller 13. A secondary transfer nip portion is formed between the intermediate transfer belt 10 and the secondary transfer roller 16, and recording paper as a recording material is fed into this portion at a predetermined timing. The recording paper is accommodated in a paper feed cassette 20 on the lower side of the exposure apparatus 4 in the drawing, and is conveyed to the secondary transfer nip portion by a paper feed roller 21 and a registration roller pair 22. Then, the toner images superimposed on the intermediate transfer belt 10 are collectively transferred onto the recording paper at the secondary transfer nip portion. At the time of this secondary transfer, a positive bias is applied to the secondary transfer roller 16, and the toner image on the intermediate transfer belt 10 is transferred onto the recording paper by the transfer electric field formed thereby.

  A heat fixing device 23 as a fixing unit is disposed downstream of the secondary transfer nip portion in the transfer paper conveyance direction. The heat fixing device 23 includes a heating roller 23a with a built-in heater and a pressure roller 23b for applying pressure. The transfer paper that has passed through the secondary transfer nip is sandwiched between these rollers and receives heat and pressure. As a result, the toner on the transfer paper is melted and the toner image is fixed on the transfer paper. Then, the fixed transfer paper is discharged by a paper discharge roller 24 onto a paper discharge tray on the upper surface of the apparatus.

[Explanation of developer]
Next, the developer suitably used in the developing device, the process cartridge, and the image forming apparatus according to the present invention will be described. In the present invention, a two-component developer comprising a toner and a carrier is used as the developer. Hereinafter, the toner and carrier used for the two-component developer will be described.

[toner]
The toner of the developer used in the present invention comprises a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous solvent. It is a toner obtained by crosslinking and / or elongation reaction. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

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

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

The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.
The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.
The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

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

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

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

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

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

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting polyvalent isocyanate (PIC) and reacting (A) and (B), a solvent may be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

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

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.
The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.
In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

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

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

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

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

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

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

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rise characteristics are not greatly impaired, and the desired charge rise characteristics can be obtained. Even if the above is repeated, stable image quality can be obtained.

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

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

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone, or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.
Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.

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

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

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

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

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

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

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

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

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

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.

  Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

Of the characteristics of the toner according to the present invention manufactured as described above, the toner volume average particle diameter is preferably 3 to 8 μm. By using a toner having a small particle size and a sharp particle size distribution, the gap between the toner particles is reduced, so that the necessary amount of toner can be reduced without impairing the color reproducibility. Therefore, density fluctuation in development can be reduced. Further, the stable reproducibility of a minute dot image of 600 dpi or more is improved, and a stable high image quality can be obtained for a long time. On the other hand, when the volume average particle diameter (D4) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur. When the volume average particle diameter (D4) exceeds 8 μm, the pile height of the image becomes large and it is difficult to suppress scattering of characters and lines. At the same time, the ratio (D4 / D1) of the volume average particle diameter (D4) to the number average particle diameter (D1) is preferably in the range of 1.00 to 1.40, preferably 1.00 to 1.30. It is more preferable if it is within the range. The closer (D4 / D1) is to 1.00, the sharper the particle size distribution.
With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

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

  First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the volume average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

Next, the shape factor SF-1 of the toner is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. FIGS. 9A and 9B are diagrams schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape, and is represented by the following formula (2). This is a value obtained by dividing the square of the maximum length MXLNG of a shape formed by projecting toner onto a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) 2 / AREA} × (100π / 4) Expression (2)
When the value of the shape factor SF-1 is 100, the shape of the toner is a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (3). This is a value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) 2 / AREA} × (100 / 4π) (3)
When the value of the shape factor SF-2 is 100, unevenness does not exist on the toner surface, and as the SF-2 value increases, the unevenness of the toner surface becomes more prominent.

Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.) and introducing it into an image analyzer (LUSEX3: manufactured by Nireco). 100 pieces were analyzed and calculated.
When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. On the other hand, if any of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

[Career]
As a carrier used in the two-component developer of the present invention, a magnetic carrier may be used, which is a ferrite containing a divalent metal such as iron, magnetite, Mn, Zn, Cu, and has a volume average particle size of 20 to 100 μm. 20-20 micrometers is more preferable. If the average particle size is less than 20 μm, carrier adhesion is likely to occur on the photoreceptor during development, and if it exceeds 100 μm, the miscibility with the toner is low, the toner charge amount is insufficient, and charging failure during continuous use is likely to occur. . Further, Cu ferrite containing Zn is preferable because of its high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus. The resin for coating the magnetic carrier is not particularly limited, and examples thereof include silicone resin, styrene-acrylic resin, fluorine-containing resin, and olefin resin. The manufacturing method may be that the coating resin is dissolved in a solvent, sprayed into the fluidized bed and coated on the core, or the resin particles are electrostatically attached to the core particles and then melted by heat to coat. You may do. The resin to be coated has a thickness of 0.05 to 10 μm, preferably 0.3 to 4 μm.

Next, as a second embodiment of the present invention, a toner replenishment control method for performing toner replenishment between sheets in the image forming apparatus described in the first embodiment is used. This toner replenishment control method has been conventionally employed to prevent image disturbance due to impact caused by driving of a toner replenishing motor, or for reasons such as toner replenishing means described in Japanese Patent Application No. 6-328274. . In such a toner replenishment control method, the toner replenishment cycle t varies depending on the paper size and paper feeding direction. In this embodiment, there are three types of paper sizes: A4 portrait, A4 landscape, and A3 landscape. The respective toner replenishment cycles are t (A4 length) = 1.33 [s], t (A4 width) = 1.87 [s], t (A3 width) = 2.66 [s]. At this time, the time T required for the developer to make a round in the developing device is the relationship of the formula (1) for all t,
(1/4 + n) .t <T <(3/4 + n) .t Formula (1)
(N = 0, 1, 2, ...)
It is desirable to make the range satisfying the above.

For example, the time T for one round of the developer is
8.645 ≦ T ≦ 8.883, 9.818 ≦ T ≦ 9.975
As shown in the following formula, the relationship of formula (1) can be satisfied for all t. In this example, the rotation speed of the stirring and conveying screw was determined so that T = 8.7 [s].

t (A4 length):
(1/4 + 6) * 1.33 = 8.313 <= T <= 8.978 = (3/4 + 6) * 1.33
(N = 6)
(1/4 + 7) * 1.33 = 9.643 ≦ T ≦ 10.308 = (3/4 + 7) * 1.33
(N = 7)
t (A4 side):
(1/4 + 4) · 1.87 = 7.948 ≦ T ≦ 8.883 = (3/4 + 4) · 1.87
(N = 4)
(1/4 + 5) · 1.87 = 9.818 ≦ T ≦ 10.753 = (3/4 + 5) · 1.87
(N = 5)
t (A3 length):
(1/4 + 3) · 2.66 = 8.645 ≦ T ≦ 9.975 = (3/4 + 3) · 2.66
(N = 3)

  In the image forming apparatus described in the second embodiment, B5 length and B5 width are added to the corresponding paper size and paper feeding direction. At this time, T satisfying the relationship of the above formula (1) at all t did not exist in the range of 8 to 10 [s]. If T is slower than this, it will lead to the problem of increasing the left-right deviation of the toner density on the developing sleeve, and making it faster than this is difficult in view of the durability of the screw bearing.

In such a case, the change in the toner concentration with a short wavelength tends to be small due to the diffusion of the developer by the developer conveying member. Therefore, T is the value of the above formula (1) with respect to the change in the toner concentration with the longest wavelength. It is desirable that the range satisfy the relationship. In this embodiment, since the longest wavelength is generated by toner replenishment with a replenishment cycle t = 2.66 [s], T is
8.645 ≦ T ≦ 9.975
It is desirable that In this embodiment, T = 9.31 [s], which is most effective by shifting the phase by π.

  In the image forming apparatus described in the second embodiment, the paper size is read from the job information, and T is always given by the above formula (1) with respect to the toner replenishment cycle t (A4 vertical), t (A4 horizontal), t (A3 horizontal). The developer transport speed u was controlled by changing the number of rotations of the screw so as to satisfy the relationship (1). In this embodiment, the screw rotation speed is set to A4 vertical: 400 [rpm], A4 horizontal: 388 [rpm], and A3 horizontal: 429 [rpm], so that T is A4 vertical: 9.975 [s]. , A4 horizontal: 10.285 [s], A3 horizontal: 9.31 [s]. As a result, phase control (T = t × n + t / 2) for efficient π can be performed efficiently under all the conditions of t, and the diffusion effect of toner density fluctuation is improved.

In the developing device described in the first embodiment, the screw conveyance efficiency changes due to the deterioration of the developer. For example, as described in the first embodiment, even when T ₀ = 9 [s] initially, it changes to T = 10 [s] with time and does not satisfy the relationship of the above formula (1). I found out.
Therefore, it was decided to measure T between papers every several hundred prints. The measuring method is as described in FIG. In this embodiment, when T deviates from the range of the above formula (1) due to a change with time, a control for changing the rotational speed of the screw to the initial T / T ₀ times is incorporated. In this way, by changing the screw rotation speed to the initial T / T ₀ times in accordance with the change in T and setting the replenishment cycle t, the phase can be always stably shifted, and the toner density fluctuation can be reduced. Can be suppressed.

  As another embodiment of the developing device used in the image forming unit, the process cartridge, and the image forming apparatus described in the first embodiment, the developed developer is collected from the developing roller, and is transported in parallel and in the same direction as the supply transport screw. And a three-axis conveyance type developing device including a collecting and conveying screw.

The difference between the configuration of the normal biaxial conveyance screw (having two developer conveyance screws, the supply conveyance screw and the agitation conveyance screw) as shown in FIG. 7 and this configuration will be described below.
In the biaxial conveying screw configuration, the developer after development falls on the supply conveying screw and is again pumped up to the developing roller. Therefore, when an image with a large image area ratio is continuously output, the developing with the toner density decreased downstream of the developing roller. The agent is used for development. Then, there is a problem that an image with insufficient image density is formed in that portion. Here, in the developing device provided with the recovery and conveyance screw of this embodiment, the developer after development is not returned to the supply and conveyance screw, but is completely collected by the recovery and conveyance screw, so that the developer having a lowered toner concentration is immediately developed. Therefore, an image with a stable image density can be obtained without depending on the area of the output image. Therefore, the toner density fluctuation due to toner consumption does not occur on the supply and conveyance screw. Further, the recovery and conveyance screw is agitated and conveyed at a certain distance and then sent to the agitation and conveyance screw. Therefore, since the change in toner density contributes only to toner replenishment, more accurate control is stably performed by the phase control mechanism described in the first to fifth embodiments, and the occurrence of background contamination and toner scattering can be suppressed.

  Hereinafter, the configuration of the three-axis conveyance type developing device 40 will be described with reference to FIG. The developing device 40 mainly includes a developing roller 41, a recovery conveyance path 43a including a recovery conveyance screw 43b, a supply conveyance path 44a including a supply conveyance screw 44b, an agitation conveyance path 45a including an agitation conveyance screw 45b, and a case partition. A portion 48, a developer layer regulating member 42, a collecting portion casing 46a, a collecting casing front end portion 46b, a toner concentration sensor 47, a toner replenishing means 50, and the like.

  The collection unit is arranged so that the axial center position of the collection conveyance screw 43b is below the developing roller 41 and above the supply conveyance screw 44b and the stirring conveyance screw 45b. The supply conveyance path 44a and the agitation conveyance path 45a communicate with each other at the end of the partition 48 and the opening so that the developer circulates. The portions other than the end and the opening are partitioned by the partition 48 of the case, and the developer does not move between the supply transport path 44a and the stirring transport path 45a. The outer diameter of the developing roller of this example was 18 mm, the outer diameter of each screw was 14 mm, and the shaft diameter was 5 mm. The screw pitch of each screw was 25 mm. Note that these values do not limit the present invention, but are examples.

The developing roller 41 is mainly composed of magnetic field generating means (for example, a magnet roller having a plurality of magnetic poles magnetized) fixed inside and a rotatable developing sleeve.
The developer pumped up from the supply transport path 44a to the developing roller 41 by the magnetic pole in the developing roller 41 is thinned by the developer layer regulating member 42 and transported to the developing area close to the photoreceptor 1 as the image carrier. Then, development is performed. The collected developer that has passed through the developing region is separated from the developing roller 41 by the repulsive magnetic pole and falls to the collecting and conveying unit 43a. The collection casing end 46b and the developing roller 41 are installed with a predetermined gap without contact.

  In the three-axis transport type developing device 40 having the above-described configuration, the developer transport screw 43b is provided so as to have a one-way circulation configuration, whereby all the developed developer is recovered by the recovery transport screw 43b and supplied and transported. Therefore, the toner density fluctuation due to the toner consumption of the developer does not occur on the supply conveyance screw 44b. Therefore, the toner density fluctuation is caused only by toner replenishment, and the phase control means of the present invention described in the first to fifth embodiments controls the phase more accurately and supplies a developer having a uniform toner density to development. be able to.

FIG. 6 is an explanatory diagram of a developer circulation path and toner density fluctuations of a biaxial conveyance type developing device according to the present invention. 2A is a diagram schematically showing a developer circulation path in the two-axis conveyance type developing device of FIG. 1 as a loop, and FIG. 2B is a point A at a certain time in the developer circulation path of FIG. FIG. 6 is a diagram illustrating a change in toner density of a developer at positions from point to point D; FIG. 10 is an explanatory diagram of a phase control method for supplying toner by shifting the phase by π so as to be different from the phase of the toner density fluctuation wave, and reducing the amplitude of the toner density fluctuation by superimposing two waves. FIG. 6 is a diagram illustrating a relationship between a time T required for the developer to make a round in the developing device, a toner supply period t, and a toner density fluctuation. (A) is an explanatory view of the installation position of the toner density sensor for measuring the developer conveyance speed u on the conveyance screw, and (b) is a diagram showing a change in the output of the toner density sensor. 1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus according to the present invention. FIG. 7 is a schematic configuration diagram illustrating a configuration around one photoconductor (image forming unit) of the image forming apparatus illustrated in FIG. 6. 1 is a schematic configuration diagram illustrating an embodiment of a three-axis conveyance type developing device according to the present invention. FIG. 4 is a diagram schematically illustrating the shape of a toner in order to explain shape factors SF-1 and SF-2.

Explanation of symbols

1 (1Y, 1C, 1M, 1K): photoconductor (latent image carrier)
3: Charging device 4: Exposure device (latent image forming means)
5: Developing device 5a: Developing roller (developer carrier)
5b: Supply conveyance screw (developer supply conveyance member)
5c: Agitating and conveying screw (developer agitating and conveying member)
5d: Partition plate 5e: Developer regulating member 5S: Toner density sensor 6: Transfer device 7: Photoconductor cleaning device 10: Intermediate transfer belt (intermediate transfer member)
11, 12, 13: Support roller 14 (14Y, 14C, 14M, 14K): Primary transfer roller 15: Belt cleaning device 16: Secondary transfer roller 20: Paper feed cassette 21: Paper feed roller 22: Registration roller pair 23: Heat fixing device (fixing means)
24: paper discharge roller 30: color image forming unit 31Y, 31C, 31M, 31K: toner bottle 40: triaxial conveyance type developing device 41: developing roller (developer carrier)
42: Developer layer regulating member 43a: Collection conveyance path 43b: Collection conveyance screw (developer collection conveyance member)
44a: supply conveyance path 44b: supply conveyance screw (developer supply conveyance member)
45a: Agitating and conveying path 45b: Agitating and conveying screw (developer agitating and conveying member)
46a: Collection unit casing 46b: Collection casing tip 47: Toner concentration sensor 48: Partition unit 50: Toner replenishing means

Claims (11)

In the developing device, a developer carrying member carrying a two-component developer composed of toner and a carrier, and a developer carrying member for carrying the developer in the axial direction facing the developer carrying member, the two-component developer is provided. In a developing device for developing and developing a latent image on a latent image carrier with developer toner,
When the average time it takes for the developer to make one revolution in the developing unit is T [s] and the toner replenishment cycle to the developer is t [s], the replenishment cycle t is calculated from the average time T. A developing device characterized in that the developing time is small and the average time T and the replenishment cycle t satisfy the relationship of the following formula (1).
(1/4 + n) .t <T <(3/4 + n) .t Formula (1)
(N = 0, 1, 2, ...) The developing device according to claim 1,
A developing device characterized in that when there are a plurality of image forming modes and the replenishment cycle t changes in accordance with the image forming modes, the relationship of the formula (1) is established for all t. The developing device according to claim 1,
A developing device characterized in that there are a plurality of image forming modes, and the relationship of the formula (1) is established with respect to the largest t when the replenishment cycle t changes according to the image forming mode. The developing device according to any one of claims 1 to 3,
A developing device having a plurality of image forming modes, and a mechanism for changing the average time T according to the change of the replenishment cycle t according to the image forming mode. The developing device according to claim 4,
The developing device, wherein the average time T is changed by changing a rotation speed of the developer conveying member. In the developing device according to any one of claims 1 to 5,
The developing device, wherein the replenishment cycle t is changed in accordance with a change with time of the average time T. In the developing device according to any one of claims 1 to 6,
Development comprising a recovery developer transport member that recovers the developer after completion of development from the developer carrier and transports the recovered developer in parallel and in the same direction as the supply developer transport member. apparatus. At least a latent image carrier on which an electrostatic latent image is formed, and a developing device that develops and visualizes the electrostatic latent image on the latent image carrier using a two-component developer composed of toner and carrier. In a process cartridge that is integrated with
A process cartridge comprising the developing device according to claim 1 as the developing device. At least a latent image carrier on which an electrostatic latent image is formed, and a developing device that develops and visualizes the electrostatic latent image on the latent image carrier using a two-component developer composed of toner and carrier. In an image forming apparatus comprising:
An image forming apparatus comprising the developing device according to claim 1 or the process cartridge according to claim 8. The image forming apparatus according to claim 9.
An image forming apparatus comprising a plurality of developing devices or process cartridges having different developing colors and forming a color image on a recording material. The image forming apparatus according to claim 10.
A plurality of image forming units or process cartridges having at least a latent image carrier and a developing device for developing an electrostatic latent image formed on the latent image carrier, and developing colors in each image forming unit or each process cartridge An image forming apparatus for forming a color image on a recording material by forming an image having different images and transferring the image directly to a recording material or via an intermediate transfer member.

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