JP2018017956A - Image forming device - Google Patents

Abstract

Even when continuous printing is performed, developability is maintained in an appropriate state, and development unevenness is suppressed. A developing device includes a storage unit that stores toner, and a toner carrier that carries the toner supplied from the storage unit. The toner carrier has a shaft and a sleeve rotatable around the shaft. The sleeve includes a sleeve base and a sleeve coat layer formed on the surface of the sleeve base. The toner includes a plurality of toner particles each including a toner mother particle and a plurality of external additive particles attached to the surface of the toner mother particle. The external additive particles have an external additive core and an external additive coat layer formed on the surface of the external additive core. Each of the external additive coat layer and the sleeve coat layer contains a thermosetting resin. The thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are polymers of the same monomers. [Selection figure] None

Description

  The present invention relates to an image forming apparatus.

  The image forming apparatus is provided with a developing device configured to develop the electrostatic latent image with toner. The developing device includes a toner carrier that carries toner, and the toner carrier has a shaft and a sleeve that can rotate around the shaft. The sleeve has a sleeve base made of, for example, aluminum or an aluminum alloy. Patent Document 1 describes a sleeve configured by forming a resin layer on the surface of a sleeve base.

JP 2011-237630 A

  When image formation is performed, the toner carrier sleeve attracts toner by magnetic force. As a result, the toner is carried on the surface of the sleeve. The toner carried on the surface of the sleeve is supplied to the photoconductor by the rotation of the sleeve and adheres to the electrostatic latent image formed on the photoconductor. In this way, a toner image is formed on the photoreceptor.

  However, when toner is carried on the surface of the sleeve described in Patent Document 1, toner particles contained in the toner may adhere to the surface of the resin layer formed on the surface of the sleeve base. Further, the toner particles may be buried in the resin layer.

  When the toner particles are fixed to the surface of the resin layer or buried in the resin layer, the toner particles supplied from the surface of the sleeve to the photoreceptor are reduced. Further, the toner particles fixed on the surface of the resin layer or buried in the resin layer tend to be excessively charged. These cause a decrease in developability.

  Further, at the portion where the toner particles are fixed on the surface of the sleeve, the toner particles are hardly attracted by the magnetic force. Therefore, on the surface of the sleeve, the toner conveyance amount differs between a portion where the toner particles are fixed and a portion where the toner particles are not fixed. As a result, uneven development tends to occur. Here, the toner conveyance amount means the amount of toner conveyed while being held on the surface of the sleeve.

  In addition, problems such as adhesion of the toner particles to the surface of the resin layer and embedding of the toner particles in the resin layer become significant when continuous printing is performed. For this reason, the decrease in developability and the occurrence of development unevenness due to this problem become significant when continuous printing is performed.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to form an image in which developability is maintained in an appropriate state and development unevenness is suppressed even when continuous printing is performed. Is to provide a device.

  An image forming apparatus according to the present invention includes a developing device configured to develop an electrostatic latent image with toner. The developing device includes a storage unit that stores the toner, and a toner carrier that supports the toner supplied from the storage unit. The toner carrier has a shaft and a sleeve rotatable around the shaft. The sleeve includes a sleeve base and a sleeve coat layer formed on the surface of the sleeve base. The toner includes a plurality of toner particles including toner mother particles and a plurality of external additive particles each attached to the surface of the toner mother particles. The external additive particles have an external additive core and an external additive coating layer formed on the surface of the external additive core. Each of the external additive coat layer and the sleeve coat layer contains a thermosetting resin. The thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are polymers of the same monomers.

  According to the image forming apparatus of the present invention, even when continuous printing is performed, developability is maintained in an appropriate state, and development unevenness is suppressed.

1 is a diagram illustrating a partial configuration of an image forming apparatus according to an exemplary embodiment. 2 is a diagram illustrating a configuration of a toner carrier provided in the image forming apparatus according to the exemplary embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of toner particles stored in a developing device of an image forming apparatus according to an embodiment of the present invention. It is an enlarged view of the area | region IV shown in FIG. FIG. 5 is a diagram showing a configuration of another toner carrier provided in the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating a configuration of another toner particle accommodated in the developing device of the image forming apparatus according to the embodiment of the present invention.

  An embodiment of the present invention will be described. It should be noted that the evaluation results (values indicating the shape or physical properties) of the powder (more specifically, toner base particles, magnetic powder, external additive, toner, etc.) are from the powder unless otherwise specified. A considerable number of average particles are selected and the number average of the values measured for each of the average particles.

Unless otherwise specified, the number average particle diameter of the powder is the number average value of the equivalent-circle diameter of the primary particles (diameter of a circle having the same area as the projected area of the particles) measured using a microscope. Moreover, the measured value of the volume median diameter (D ₅₀ ) of the powder is measured using a laser diffraction / scattering particle size distribution measuring device (“LA-750” manufactured by Horiba, Ltd.) unless otherwise specified. It is the value.

  The chargeability means the chargeability in frictional charging unless otherwise specified. The strength of positive charging in frictional charging or the strength of negative charging in frictional charging can be confirmed by a known charge train or the like.

  Hereinafter, a compound and its derivatives may be generically named by adding “system” after the compound name. When the name of a polymer is expressed by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof. Acrylic and methacrylic are sometimes collectively referred to as “(meth) acrylic”. Further, acrylonitrile and methacrylonitrile may be collectively referred to as “(meth) acrylonitrile”.

[Configuration of Image Forming Apparatus According to Present Embodiment]
The image forming apparatus according to the present embodiment includes a developing device configured to develop an electrostatic latent image with toner. The developing device includes a storage unit that stores toner, and a toner carrier that carries the toner supplied from the storage unit. The toner carrier has a shaft and a sleeve rotatable around the shaft. The sleeve includes a sleeve base and a sleeve coat layer formed on the surface of the sleeve base. The toner includes a plurality of toner particles each including a toner mother particle and a plurality of external additive particles attached to the surface of the toner mother particle. The external additive particles have an external additive core and an external additive coat layer formed on the surface of the external additive core. Each of the external additive coat layer and the sleeve coat layer contains a thermosetting resin. The thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are polymers of the same monomers. Thereby, even when continuous printing is performed, the developability is maintained in an appropriate state, and the occurrence of development unevenness is suppressed.

  Hereinafter, an example of the configuration of the image forming apparatus according to the present embodiment, a preferable configuration of the image forming apparatus according to the present embodiment, and another preferable configuration of the image forming apparatus according to the present embodiment will be described with reference to the drawings. Note that any of the image forming apparatuses described below is an image forming apparatus when image formation is performed using a one-component developer. However, the image forming apparatus of this embodiment includes an image forming apparatus in the case of performing image formation using a two-component developer. Hereinafter, the sleeve of the toner carrier may be simply referred to as a sleeve.

[Example of Configuration of Image Forming Apparatus According to Present Embodiment]
An example of the configuration of the image forming apparatus according to the present embodiment will be described with reference to FIGS. FIG. 1 is a diagram illustrating a partial configuration of the image forming apparatus according to the present embodiment. Specifically, FIG. 1 mainly describes the configuration of the developing device provided in the image forming apparatus according to the present embodiment. FIG. 2 is a diagram showing a configuration of a toner carrier provided in the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration of toner particles accommodated in the developing device of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is an enlarged view of region IV shown in FIG. In FIG. 4, a part of the description of the toner particles is omitted.

  As shown in FIG. 1, the developing device 1 of the image forming apparatus according to the present embodiment includes a developing roller 10 as a toner carrier, and a storage portion R that stores toner. Hereinafter, after describing the configuration of the developing roller 10, the configuration of the toner will be described.

  The developing roller 10 is configured to carry the toner supplied from the storage portion R. As shown in FIGS. 1 and 2, the developing roller 10 includes a shaft 11, a magnet roll 12, and a cylindrical sleeve 13. The magnet roll 12 is fixed to the shaft 11 and is located in the sleeve 13 (inside the cylinder). Moreover, the magnet roll 12 has a magnetic pole at least in the surface layer part. As a magnetic pole which magnet roll 12 has, N pole and S pole based on a permanent magnet are mentioned, for example. The sleeve 13 is positioned on the surface layer portion of the developing roller 10 and is supported so as to be able to rotate around the shaft 11. Specifically, the shaft 11 and the sleeve 13 are connected by the flange portions 13 a and 13 b so that the sleeve 13 can rotate around the non-rotating magnet roll 12. With this structure, the sleeve 13 can rotate in the circumferential direction of the shaft 11 (the direction of the arrow in FIG. 1).

  As shown in FIGS. 1 and 2, the sleeve 13 includes a sleeve base 130 and a sleeve coat layer 132. As shown in FIG. 2, no irregularities are formed on the surface of the sleeve base 130, and the surface of the sleeve base 130 is smooth. The sleeve coat layer 132 is formed on the surface of the sleeve base 130 and contains a thermosetting resin.

  The toner includes a plurality of toner particles 60. As shown in FIG. 3, the toner particles 60 include toner base particles 61 and a plurality of external additive particles 62. As shown in FIG. 3, the toner base particles 61 do not have a shell layer and are non-capsule toner particles. The external additive particles 62 are attached to the surface of the toner base particles 61 and have an external additive core 620 and an external additive coat layer 622. The external additive coat layer 622 is formed on the surface of the external additive core 620 and contains a thermosetting resin. The thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are a polymer of the same monomers.

  As shown in FIG. 1, the image forming apparatus according to the present embodiment further includes a photosensitive drum 20, a charging device 21, an exposure device 22, a cleaning member 23, a toner charging member 30, and a toner supply roller 40. Hereinafter, the configuration of the image forming apparatus according to the present embodiment will be further described by showing an image forming method using the image forming apparatus shown in FIG.

  In the image forming apparatus according to the present embodiment, the sleeve 13 of the developing roller 10, the photosensitive drum 20, and the toner supply roller 40 rotate in the direction of the arrow in FIG. Done.

  Specifically, first, the charging device 21 uniformly charges the photosensitive layer of the photosensitive drum 20. Next, the exposure device 22 forms an electrostatic latent image on the photosensitive layer of the photosensitive drum 20 based on the image data. Subsequently, the developing device 1 develops the electrostatic latent image formed on the photosensitive layer of the photosensitive drum 20 using toner containing toner particles 60.

  Specifically, the toner supply roller 40 supplies toner from the storage portion R to the developing roller 10. At this time, the sleeve 13 of the developing roller 10 attracts the toner particles 60 contained in the toner by the magnetic force of the magnet roll 12. As a result, the toner particles 60 are carried on the surface of the sleeve 13 of the developing roller 10. The toner particles 60 carried on the surface of the sleeve 13 are charged by friction with the toner charging member 30. At this time, the positively chargeable toner is positively charged by friction. The negatively chargeable toner is negatively charged by friction. The charged toner particles 60 are supplied to the photosensitive drum 20 by the rotation of the sleeve 13 of the developing roller 10. As a result, the toner particles 60 adhere to the electrostatic latent image formed on the photosensitive layer of the photosensitive drum 20, thereby forming a toner image on the photosensitive layer. In this way, the electrostatic latent image formed on the photosensitive layer is developed.

  Subsequently, the toner image on the photosensitive layer of the photosensitive drum 20 is transferred to a recording medium (for example, printing paper). Thereafter, the toner particles 60 are heated and pressurized by the fixing device to fix the toner particles 60 on the recording medium. As a result, an image is formed on the recording medium. After the image is formed, the toner particles 60 remaining on the photosensitive layer are removed by the cleaning member 23.

  As described above, in the image forming apparatus according to the present embodiment, the toner particles 60 are carried on the surface of the sleeve 13 of the developing roller 10 during development. Here, the toner particles 60 include a plurality of external additive particles 62 that adhere to the surface of the toner base particles 61, and the external additive particles 62 are formed on the surface of the external additive core 620. 622. Further, the sleeve 13 of the developing roller 10 includes a sleeve coat layer 132 formed on the surface of the sleeve base 130. Therefore, as shown in FIG. 4, when the toner particles 60 are carried on the surface of the sleeve 13 of the developing roller 10, the external additive coat layer 622 can easily come into contact with the sleeve coat layer 132.

  The thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are polymers of the same monomers. As a result, the external additive coat layer 622 and the sleeve coat layer 132 are charged to the same polarity, so that the external additive coat layer 622 and the sleeve coat layer 132 are electrically repelled. Therefore, even if the external additive coat layer 622 and the sleeve coat layer 132 come into contact with each other because the toner particles 60 are carried on the surface of the sleeve 13, the toner particles 60 can be prevented from being fixed and buried in the sleeve coat layer 132. .

  Thus, the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are polymers of the same monomers. Therefore, even when continuous printing is performed, the external additive coat layer 622 and the sleeve coat layer 132 are easily charged to the same polarity. Therefore, the external additive coat layer 622 and the sleeve coat layer 132 are electrically Repulsively. Therefore, even when continuous printing is performed, the toner particles 60 can be prevented from being fixed and buried in the sleeve coat layer 132.

  Further, the external additive coat layer 622 and the sleeve coat layer 132 each contain a thermosetting resin. Thermosetting resins are relatively hard. Therefore, the hardness of each of the external additive coat layer 622 and the sleeve coat layer 132 is increased. Therefore, even if the external additive coat layer 622 and the sleeve coat layer 132 come into contact with each other because the toner particles 60 are carried on the surface of the sleeve 13, the toner particles 60 can be prevented from being fixed and buried in the sleeve coat layer 132. .

  Thus, the external additive coat layer 622 and the sleeve coat layer 132 each contain a thermosetting resin. Therefore, even when continuous printing is performed, the hardness of each of the external additive coat layer 622 and the sleeve coat layer 132 can be maintained high. Therefore, even when continuous printing is performed, the toner particles 60 can be prevented from being fixed and buried in the sleeve coat layer 132.

  If the toner particles 60 are prevented from being fixed and buried in the sleeve coat layer 132, the toner particles 60 supported on the surface of the sleeve 13 are supplied to the photosensitive drum 20. In addition, excessive charging of the toner particles 60 on the surface of the sleeve 13 can be prevented, and thus deterioration of the toner particles 60 can be prevented. From these things, developability can be maintained in an appropriate state. Here, sticking and embedding of the toner particles 60 to the sleeve coat layer 132 is prevented even when continuous printing is performed. Therefore, developability can be maintained in an appropriate state even when continuous printing is performed.

  Further, if the toner particles 60 are prevented from being fixed and buried in the sleeve coat layer 132, the toner particles 60 are attracted uniformly due to the magnetic force. As a result, the toner conveyance amount becomes uniform on the surface of the sleeve coat layer 132. That is, a thin toner layer having a uniform thickness is formed on the surface of the sleeve coat layer 132. Therefore, development unevenness can be prevented. Here, sticking and embedding of the toner particles 60 to the sleeve coat layer 132 is prevented even when continuous printing is performed. Therefore, even when continuous printing is performed, development unevenness can be prevented.

  The sleeve coat layer 132 may be formed over the entire surface area of the sleeve base 130, but it is sufficient that the sleeve coat layer 132 be formed in at least the area where the toner particles 60 are carried in the surface area of the sleeve base 130.

  The thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 may be a polymer of the same monomer. The polymerization degree of the monomer may be the same or different between the thermosetting resin contained in the external additive coating layer 622 and the thermosetting resin contained in the sleeve coating layer 132. . Here, the “monomer” in describing each of the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 includes a compound that functions as a crosslinking agent. I can't. Further, the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 may each include a repeating unit derived from a crosslinking agent. In this case, the chemical structure of the repeating unit derived from the crosslinking agent may be the same between the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132. Good or different from each other. In addition, only one of the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 may include a repeating unit derived from the crosslinking agent.

  The toner is preferably a positively chargeable toner. In this case, the thermosetting resin contained in the external additive coating layer 622 and the thermosetting resin contained in the sleeve coating layer 132 are each a polymer of monomers containing nitrogen atoms in the chemical structure. preferable. Since a polymer of a monomer containing a nitrogen atom in the chemical structure has a relatively strong positive chargeability, the toner is easily positively charged by friction. Therefore, if the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are each a polymer of monomers containing nitrogen atoms in the chemical structure, toner It becomes easy to charge the particles 60 positively. Therefore, the toner charge amount can be stabilized within an appropriate range. Examples of the polymer of monomers containing nitrogen atoms in the chemical structure include melamine resins and urea resins.

  Specifically, when the thermosetting resin contained in the external additive coat layer 622 is a melamine resin, the thermosetting resin contained in the sleeve coat layer 132 is preferably a melamine resin. In this case, it is only necessary that the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 have the same chemical structure of the repeating unit derived from the monomer. When each of the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 is a melamine resin, the “repeating unit derived from the monomer” has melamine. This means that one hydrogen atom is removed from at least one amino group of amino groups.

  Further, when the thermosetting resin contained in the external additive coat layer 622 is a urea resin, the thermosetting resin contained in the sleeve coat layer 132 is preferably a urea resin. In this case, it is only necessary that the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 have the same chemical structure of the repeating unit derived from the monomer. When each of the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 is a urea resin, the “repeating unit derived from the monomer” has urea. This means that one hydrogen atom is removed from at least one amino group of amino groups.

  The external additive coat layer 622 only needs to contain a polymer of a monomer containing a nitrogen atom in the chemical structure as a main component. For example, the external additive coat layer 622 may contain 10% by mass or less of a polymer of a monomer not containing a nitrogen atom in the chemical structure, or may contain 10% by mass or less of a thermoplastic resin. More specifically, the external additive coating layer 622 only needs to contain a melamine resin or a urea resin as a main component, and may contain 10% by mass or less of a thermosetting resin different from the melamine resin and the urea resin. The thermoplastic resin may be contained in an amount of 10% by mass or less. The same can be said for the sleeve coat layer 132.

  The toner may be a negatively chargeable toner. In this case, it is preferable that the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are each a phenol resin. Since the phenol resin has a relatively strong negative charging property, the toner is easily negatively charged by friction. Therefore, if the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 are each a phenol resin, the toner particles 60 are easily negatively charged. Therefore, the toner charge amount can be stabilized within an appropriate range.

[Preferred Configuration of Image Forming Apparatus According to Present Embodiment]
A preferred configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 5 is a diagram showing a configuration of another developing roller provided in the image forming apparatus according to the embodiment of the present invention. In the developing roller shown in FIG. 5, irregularities are formed on the surface of the sleeve base 130. Concavities and convexities corresponding to the concavities and convexities formed on the surface of the sleeve base 130 are formed on the surface of the sleeve coat layer 132. Specifically, on the surface of the sleeve coat layer 132, there are a convex portion P1 corresponding to the convex portion formed on the surface of the sleeve base 130 and a concave portion P2 corresponding to the concave portion formed on the surface of the sleeve base 130. Is formed. As a result, the sleeve coat layer 132 is firmly fixed to the surface of the sleeve base 130. Therefore, even when continuous printing is performed, it is possible to prevent the sleeve coat layer 132 from being detached from the sleeve base 130. Therefore, even when continuous printing is performed, developability is easily maintained in an appropriate state, and development unevenness can be further prevented. Further, the durability of the sleeve 13 can be enhanced.

  In addition, if the surface of the sleeve coat layer 132 has irregularities corresponding to the irregularities formed on the surface of the sleeve base 130, the developing roller 10 (see, for example, FIG. 1) has sufficient toner transportability. It becomes easy to do. That is, a thin toner layer is stably formed on the surface of the sleeve base 130. As a result, the toner charge amount can be maintained within an appropriate range. Therefore, the occurrence of fogging can be prevented and the occurrence of gradation failure can be prevented.

  When irregularities are formed on the surface of the sleeve base 130, the sleeve 13 preferably has a surface treatment layer 131 between the sleeve base 130 and the sleeve coat layer 132. The surface treatment layer 131 is formed on the surface of the sleeve base 130 where the irregularities are formed, and contains a coupling agent. In such a sleeve 13, the sleeve coat layer 132 is firmly fixed to the sleeve base 130 by the surface treatment layer 131. Therefore, even when continuous printing is performed, the sleeve coat layer 132 can be further prevented from being detached from the sleeve base 130. Therefore, even when continuous printing is performed, developability is more easily maintained in an appropriate state, and development unevenness can be further prevented. Further, the durability of the sleeve 13 can be further enhanced.

  In addition, if the surface treatment layer 131 is formed between the sleeve base 130 and the sleeve coat layer 132, the surface of the sleeve coat layer 132 has irregularities corresponding to the irregularities formed on the surface of the sleeve base 130. Is easily formed. As a result, the developing roller 10 (see, for example, FIG. 1) is more likely to have sufficient toner transportability. That is, the toner thin layer is more stably formed on the surface of the sleeve base 130. Therefore, the toner charge amount is easily maintained within an appropriate range. Therefore, the generation of fog can be further prevented, and the occurrence of gradation defects can be further prevented.

  For example, the average surface roughness (hereinafter referred to as the covering sleeve roughness) of the developing roller in a state where the sleeve base 130 is covered with the surface treatment layer 131 and the sleeve coat layer 132 is preferably 10 μm or less. As a result, the frictional force generated between the surface of the sleeve coat layer 132 and the toner particles 60 due to the contact between the surface of the sleeve coat layer 132 and the toner particles 60 (see, for example, FIG. 3) becomes excessive. Can be prevented. Therefore, the deterioration of the toner particles 60 can be further prevented. Further, the toner particles 60 can be further prevented from sticking to the sleeve coat layer 132.

  If the covering sleeve roughness is 10 μm or less, the developing roller 10 (see, for example, FIG. 1) has sufficient toner transportability. Therefore, the toner charge amount is easily maintained within an appropriate range. Therefore, the generation of fog can be further prevented, and the occurrence of gradation defects can be further prevented.

Further, when the covering sleeve roughness is 10 μm or less, particles having a volume median diameter (D ₅₀ ) smaller than that of the toner particles 60 (see, for example, FIG. 3) enter or accumulate in the concave portion P2 of the sleeve coat layer 132. Can be prevented. Thereby, the fluctuation | variation of the covering sleeve roughness during image formation can be prevented. Specifically, it is possible to prevent a decrease in the covering sleeve roughness during image formation. Examples of the particles having a volume median diameter (D ₅₀ ) smaller than that of the toner particles 60 include a toner component and impurities.

  If fluctuations in the roughness of the covering sleeve during image formation can be prevented, the frictional force can be prevented from becoming excessive even when continuous printing is performed. Thereby, even when continuous printing is performed, deterioration of the toner particles 60 (see, for example, FIG. 3) can be further prevented, and adhesion of the toner particles 60 to the sleeve coat layer 132 can be further prevented. For these reasons, even when continuous printing is performed, the developability is more easily maintained in an appropriate state, and development unevenness can be further prevented. The “frictional force” means a frictional force generated between the surface of the sleeve coat layer 132 and the toner particles 60 due to the contact between the surface of the sleeve coat layer 132 and the toner particles 60.

  Further, if the variation in the roughness of the covering sleeve during the image formation can be prevented, the variation in the toner transportability of the developing roller can be prevented even when continuous printing is performed. Specifically, if it is possible to prevent the covering sleeve roughness from being lowered during image formation, it is possible to prevent the toner transportability of the developing roller from being lowered even when continuous printing is performed. Therefore, a decrease in M / S on the sleeve 13 can be prevented. M / S means the mass of toner per unit area.

  Here, the measuring method of the covering sleeve roughness conforms to the measuring method of the ten-point average surface roughness Rzjis in “JIS B0601”. The covering sleeve roughness may be 0 μm or more, and is preferably 5 μm or more. The roughness of the covering sleeve being 0 μm means that the surface of the sleeve coat layer 132 is not uneven, and means that the surface of the sleeve coat layer 132 is smooth.

[Preferred Another Configuration of Image Forming Apparatus According to This Embodiment]
With reference to FIG. 6, another preferred configuration of the image forming apparatus according to the present embodiment will be described. FIG. 6 is a diagram illustrating a configuration of another toner particle included in the image forming apparatus according to the embodiment of the present invention. The toner particles 60 shown in FIG. 3 and the toner particles 60 shown in FIG. Specifically, the toner base particles 61 shown in FIG. 6 have a toner core 610 and a shell layer 611, and the shell layer 611 is formed on the surface of the toner core 610. That is, the toner base particles 61 shown in FIG. 6 are capsule toner particles. In this case, it is preferable that the resin contained in the shell layer 611 and the thermosetting resin contained in the external additive coat layer 622 are polymers of different monomers. In addition, the resin contained in the shell layer 611 and the thermosetting resin contained in the sleeve coat layer 132 (see, for example, FIG. 2 or 5) are preferably polymers of different monomers. As a result, the shell layer 611 and the external additive coat layer 622 are charged with different polarities, and the shell layer 611 and the sleeve coat layer 132 are charged with different polarities. Therefore, the toner particles 60 are easily charged. Therefore, even when continuous printing is performed, the toner charge amount is easily maintained within an appropriate range, so that fluctuations in image density can be suppressed.

  For example, when the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 each have positive chargeability, the resin contained in the shell layer 611 is: It preferably has negative chargeability. Thereby, the toner particles 60 are easily positively charged. Therefore, even when continuous printing is performed, the toner charge amount is easily maintained within an appropriate range, so that fluctuations in image density can be suppressed.

  For example, when the thermosetting resin contained in the external additive coat layer 622 and the thermosetting resin contained in the sleeve coat layer 132 each have negative chargeability, the resin contained in the shell layer 611 is: It preferably has positive chargeability. Thereby, the toner particles 60 are easily negatively charged. Therefore, even when continuous printing is performed, the toner charge amount is easily maintained within an appropriate range, so that fluctuations in image density can be suppressed.

  If the resin contained in the shell layer 611 and the thermosetting resin contained in the external additive coating layer 622 and the thermosetting resin contained in the sleeve coating layer 132 are polymers of different monomers, the shell The resin contained in the layer 611 is not particularly limited. The resin contained in the shell layer 611 may be a thermosetting resin or a thermoplastic resin. However, if the resin contained in the shell layer 611 is a thermoplastic resin, the low-temperature fixability of the toner can be improved.

  When the toner base particles 61 have the toner core 610 and the shell layer 611, the external additive particles 62 adhere to the surface of the shell layer 611 as shown in FIG.

  1 to 6, an example of the configuration of the image forming apparatus according to the present embodiment, a preferable configuration of the image forming apparatus according to the present embodiment, and another preferable configuration of the image forming apparatus according to the present embodiment. Explained. Note that the image forming apparatus according to the embodiment of the present invention may include the toner particles 60 illustrated in FIG. 3 and the toner particles 60 illustrated in FIG. 6. Hereinafter, a method for producing a sleeve included in a toner carrier, a method for producing toner, an example of a material of a constituent member of the toner carrier, an example of a constituent material of toner particles, and an example of use of the toner will be exemplified in order.

[Method for producing sleeve contained in toner carrier]
A sleeve having a sleeve base and a sleeve coat layer is produced according to the following method. First, a sleeve base is prepared, and a sleeve coat layer is formed on the surface of the sleeve base. As a method for forming the sleeve coat layer, a dip coating method can be used. Specifically, first, a first solution is prepared. The first solution to be prepared includes at least one of a thermosetting resin, a monomer capable of generating a thermosetting resin by a polymerization reaction, and a reaction intermediate capable of generating a thermosetting resin by a polymerization reaction. When preparing the first solution, the thermosetting resin means a thermosetting resin that the sleeve coat layer contains. Next, the sleeve base is immersed in the prepared first solution. As a result, a first coating film containing the first solution is formed on the surface of the sleeve base. Subsequently, the first coating film formed on the surface of the sleeve base is cured. In this way, a sleeve coat layer is formed on the surface of the sleeve base. When the sleeve coat layer is formed by the dip coating method, a sleeve coat layer having a uniform thickness is formed. In order to make the thickness of the sleeve coat layer more uniform, it is preferable to form the sleeve coat layer by a chemical reaction method.

  When forming a melamine resin layer as a sleeve coat layer, it is preferable to prepare a solution containing methylol melamine as the first solution. Moreover, when forming a urea resin layer as a sleeve coat layer, it is preferable to prepare a solution containing methylol urea as the first solution.

  A sleeve having a sleeve base, a surface treatment layer, and a sleeve coat layer is produced according to the following method. First, a sleeve base having an uneven surface is prepared. As a method for forming irregularities on the surface of the sleeve base, a method of blasting the surface of the sleeve base may be mentioned. A specific example of blasting is sand blasting.

  Next, the surface of the sleeve base on which the irregularities are formed is treated with a silane coupling agent. For example, it is preferable to treat the surface of the sleeve substrate on which the irregularities are formed by a dip coating method, a spray method, or a roll coating method. Thereby, a surface treatment layer containing a silane coupling agent is formed on the surface of the sleeve base where the irregularities are formed.

  Subsequently, a sleeve coat layer is formed on the surface treatment layer by a dip coating method. Specifically, first, a second solution is prepared. The second solution to be prepared includes at least one of a thermosetting resin, a monomer capable of generating a thermosetting resin by a polymerization reaction, and a reaction intermediate capable of generating a thermosetting resin by a polymerization reaction. When preparing the second solution, the thermosetting resin means a thermosetting resin that the sleeve coat layer contains. Next, the sleeve substrate on which the surface treatment layer is formed is immersed in the prepared second solution. Thereby, the 2nd coating film containing a 2nd solution is formed in the surface of a surface treatment layer. Subsequently, the second coating film formed on the surface of the surface treatment layer is cured. Thereby, the silane coupling agent contained in the surface treatment layer reacts with the thermosetting resin, monomer, or reaction intermediate contained in the second coating film. In this way, a sleeve coat layer is formed on the surface treatment layer.

  When the melamine resin layer is formed as the sleeve coat layer, it is preferable to prepare a solution containing methylol melamine as the second solution. Moreover, when forming a urea resin layer as a sleeve coat layer, it is preferable to prepare a solution containing methylol urea as the second solution.

[Toner Preparation Method]
A preferred method for producing the toner includes a toner mother particle preparation step, an external additive preparation step, and an external addition step. When the toner base particles do not have a shell layer, the toner base particles are prepared by preparing the toner core according to the following (preparation of toner base particles: preparation of toner core). When the toner base particles have a shell layer, the toner base particles are prepared by sequentially performing the following (preparation of toner base particles: preparation of toner core) and the following (preparation of toner base particles: formation of shell layer). .

  Note that at least one of a filtration step and a drying step may be performed between the toner mother particle preparation step and the external addition step. In the filtration step, the toner base particles are recovered from the dispersion of the toner base particles. In the drying step, the collected toner mother particles are dried. In order to produce the toner efficiently, it is preferable to form a large number of toner particles simultaneously. The toner particles produced at the same time are considered to have substantially the same configuration.

(Preparation of toner mother particles: Preparation of toner core)
The toner core is preferably produced by a known agglomeration method or a known pulverization method. Thereby, a toner core can be obtained easily.

(Preparation of toner mother particles: formation of shell layer)
For example, the shell layer can be formed using any one of an in-situ polymerization method, a submerged cured coating method, and a coacervation method.

(Preparation of external additives)
The external additive is preferably prepared according to the following method. First, an external additive core is prepared, and an external additive coat layer is formed on the surface of the external additive core. As a method of forming the external additive coating layer, a dip coating method can be used. Specifically, first, a third solution is prepared. The third solution to be prepared includes at least one of a thermosetting resin, a monomer capable of generating a thermosetting resin by a polymerization reaction, and a reaction intermediate capable of generating a thermosetting resin by a polymerization reaction. When preparing the third solution, the thermosetting resin means a thermosetting resin that the external additive coating layer contains. Next, the external additive core is immersed in the prepared third solution. As a result, a third coating film containing the third solution is formed on the surface of the external additive core. Subsequently, the third coating film formed on the surface of the external additive core is cured. Thereby, an external additive coat layer is formed on the surface of the external additive core. In this way, an external additive containing a plurality of external additive particles is obtained. If the external additive coat layer is formed by a dip coating method, an external additive coat layer having a uniform thickness is formed. In order to make the thickness of the external additive coat layer more uniform, it is preferable to form the external additive coat layer by a chemical reaction method.

  When forming a melamine resin layer as an external additive coating layer, it is preferable to prepare a solution containing methylolmelamine as the third solution. Moreover, when forming a urea resin layer as an external additive coating layer, it is preferable to prepare a solution containing methylol urea as the third solution.

  An example will be given in which hydrophilic silica particles are used as the external additive core and a melamine resin layer is formed as the external additive coating layer. In this case, it is preferable to prepare an acidic aqueous solution containing methylolmelamine as the third solution. Thereby, the silanol group contained in the external additive core and the methylol group contained in methylolmelamine are easily covalently bonded. Therefore, the external additive coat layer is easily formed uniformly on the surface of the external additive core. Here, the hydrophilic silica particles mean silica particles that have not been subjected to hydrophobic treatment. As the hydrophilic silica particles, for example, hydrophilic fumed silica particles can be used. Even when particles made of a material different from hydrophilic silica are used as an external additive core, a melamine resin layer (an example of an external additive coating layer) is formed on the surface of the external additive core according to the above method. It is preferable to do.

  An example in which hydrophilic silica particles are used as the external additive core and a urea resin layer is formed as the external additive coating layer will be described. In this case, it is preferable to prepare an acidic aqueous solution containing methylol urea as the third solution. Thereby, the silanol group contained in the external additive core and the methylol group contained in the methylol urea are easily covalently bonded. Therefore, the external additive coat layer is easily formed uniformly on the surface of the external additive core. Even when particles made of a material different from hydrophilic silica are used as an external additive core, a urea resin layer (an example of an external additive coating layer) is formed on the surface of the external additive core according to the above method. It is preferable to do.

  In order to efficiently produce an external additive, it is preferable to form a large number of external additive particles simultaneously. The external additive particles produced at the same time are considered to have substantially the same configuration.

(External)
The toner base particles and the external additive are mixed using a mixer (for example, an FM mixer manufactured by Nippon Coke Kogyo Co., Ltd.). As a result, the external additive is physically bonded to the surface of the toner base particles. In this way, a toner containing a large number of toner particles is obtained.

[Examples of materials of constituent members of toner carrier]
The toner carrier includes a shaft, a magnet roll, and a cylindrical sleeve. The shaft is made of metal, for example. Here, as a metal, iron is mentioned, for example. Moreover, as a magnet roll, 1 or more types of magnets selected from the group which consists of a ferrite magnet, a plastic magnet, and a rare earth bond magnet, for example are preferable.

(Sleeve: Sleeve base)
The sleeve includes a sleeve base and a sleeve coat layer. The sleeve base is a non-magnetic cylinder. As a material of the sleeve base, for example, one or more nonmagnetic metals selected from the group consisting of aluminum, aluminum alloy, stainless steel, stainless steel alloy, brass, and brass alloy are preferable, and aluminum or aluminum alloy is more preferable. . For stainless steel, SUS303, SUS304, or SUS316 is particularly preferred. For aluminum alloys, A6063, A5056 or A3003 is particularly preferred.

(Sleeve: Sleeve coat layer)
The resin contained in the sleeve coat layer is preferably a melamine resin or a urea resin.

(Sleeve coat layer: Melamine resin)
The melamine resin is obtained by condensation polymerization of melamine and formaldehyde. Specifically, melamine and formaldehyde are subjected to an addition reaction. Thereby, methylol melamine (a precursor of melamine resin) is obtained. The obtained methylol melamine is subjected to a condensation reaction. Thereby, the amino group of one methylol melamine couple | bonds with the amino group of another methylol melamine through a methylene group. As a result, a melamine resin is obtained. The obtained melamine resin contains a repeating unit derived from melamine.

  The solubility of methylol melamine in water can be changed by changing the type or number of functional groups of methylol melamine. For this reason, it is relatively easy to polymerize methylolmelamine in an aqueous medium.

(Sleeve coat layer: urea resin)
The urea resin is obtained by condensation polymerization of urea and formaldehyde. Specifically, the urea resin can be synthesized by using urea instead of melamine in the melamine resin synthesis method. The synthesized urea resin contains repeating units derived from urea.

(Sleeve: Surface treatment layer)
Preferably, the sleeve has a surface treatment layer between the sleeve base and the sleeve coat layer. As a coupling agent which a surface treatment layer contains, a silane coupling agent, a titanate coupling agent, or an aluminate coupling is mentioned, for example. The silane coupling agent is represented by the following formula (1).

In formula (1), Y is a reactive functional group (more specifically, an amino group (—NH ₂ ), a vinyl group (—CH═CH ₂ ), an isocyanate group (—N═C═O) at the end. ), A mercapto group (—SH), a ureido group (—NHCONH ₂ ), an epoxy group, or a (meth) acryloyl group). This reactive organic functional group (Y) binds by chemically reacting with an organic material (more specifically, an acid, an ester, an epoxy, a ketone, or a halide). N represents an integer of 1 to 3. X ¹ each independently represents a hydrolyzable group (more specifically, an alkoxy group or the like). The hydrolyzable group is hydrolyzed with water or moisture to produce silanol. The produced silanol reacts with the inorganic material. X ² each independently represents an alkyl group. However, when n represents 3, X ² does not exist.

  In order to positively triboelectrically charge the toner, the coupling agent contained in the surface treatment layer is preferably a coupling agent having neither an amino group nor an amide group. As the coupling agent contained in the surface treatment layer, a coupling agent having an epoxy group is preferable, and glycidyloxyalkylalkoxysilane is particularly preferable. Examples of the glycidyloxyalkylalkoxysilane include 3-glycidoxypropyltriethoxysilane represented by the formula (2).

[Examples of constituent materials of toner particles]
The toner particles include toner base particles and external additive particles. In the following, after illustrating the material of the external additive particles, the material of the toner base particles is illustrated.

(External additive particles)
The external additive particles are used, for example, to improve the fluidity of toner particles or the handling properties of toner. In order to improve the fluidity of the toner particles or the handleability of the toner, the amount of the external additive particles may be 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner base particles. preferable. In order to improve the fluidity of the toner particles or the handleability of the toner, the volume median diameter (D ₅₀ ) of the external additive particles is preferably 0.01 μm or more and 1.0 μm or less.

  The external additive particles have an external additive core and an external additive coat layer. One type of external additive particles may be used alone, or a plurality of types of external additive particles may be used in combination.

(External additive particles: external additive core)
The external additive core is preferably inorganic particles, and more preferably silica particles or particles made of a metal oxide. As the silica particles, it is preferable to use hydrophilic silica particles, and for example, hydrophilic fumed silica particles can be suitably used. As the metal oxide, for example, alumina, zirconia, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, or barium titanate can be used.

  The external additive core may be organic acid compound particles or resin particles. The external additive core may be composite particles made of a plurality of types of materials. Here, a fatty acid metal salt can be used as the organic acid compound. Specific examples of fatty acid metal salts include zinc stearate.

(External additive particles: external additive coating layer)
When the resin contained in the sleeve coat layer is a melamine resin, the resin contained in the external additive coat layer is preferably a melamine resin. As the melamine resin, the melamine resin described in the above (sleeve coat layer: melamine resin) can be used.

  When the resin contained in the sleeve coat layer is a urea resin, the resin contained in the external additive coat layer is preferably a urea resin. As the urea resin, the urea resin described in the above (sleeve coat layer: urea resin) can be used.

(Toner mother particles)
The toner base particles may be composed only of a toner core, or may have a toner core and a shell layer.

(Toner mother particles: toner core)
The toner core contains a binder resin, and may contain an internal additive as necessary. Examples of the internal additive include a release agent, a colorant, a charge control agent, and magnetic powder. Depending on the use of the toner, unnecessary components may be omitted. Examples of unnecessary components include a colorant, a release agent, and a charge control agent.

(Toner core: Binder resin)
By using a combination of a plurality of types of resins as the binder resin, the properties of the binder resin (more specifically, the hydroxyl value, acid value, Tg, Tm, etc.) can be adjusted. For example, when the binder resin has an ester group, a hydroxyl group (OH group), an ether group, an acid group, or a methyl group, the toner core tends to become anionic. Further, when the binder resin has an amino group or an amide group, the toner core tends to be cationic. In order for the binder resin to have strong anionicity, it is preferable that at least one of the acid value and the hydroxyl value of the binder resin is 10 mgKOH / g or more.

  It is preferable to use a thermoplastic resin as the binder resin. Thereby, the fixing property of the toner is improved. As the thermoplastic resin, for example, styrene resin, acrylic resin, olefin resin, vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, N-vinyl resin, polyester resin, polyamide resin, or urethane resin are preferable. As the acrylic resin, for example, an acrylic ester polymer or a methacrylic ester polymer can be used. As the olefin resin, for example, a polyethylene resin or a polypropylene resin can be used. Further, as the binder resin, a copolymer of each of these resins, that is, a copolymer in which an arbitrary repeating unit is introduced into the resin can be used. More specifically, a styrene-acrylic acid resin or a styrene- Butadiene resins can be used.

  More preferably, a styrene-acrylic acid resin or a polyester resin is used as the binder resin. Thereby, the dispersibility of the colorant in the toner, the charging property of the toner, and the fixing property of the toner to the recording medium are improved. Hereinafter, the styrene-acrylic acid resin and the polyester resin will be described in order.

(Binder resin: Styrene-acrylic acid resin)
The styrene-acrylic acid resin is a copolymer of one or more styrene monomers and one or more acrylic monomers. Examples of the styrene monomer for synthesizing the styrene-acrylic acid resin include styrene, α-methylstyrene, p-hydroxystyrene, m-hydroxystyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m. -Chlorostyrene, p-chlorostyrene, or p-ethylstyrene is preferred.

  As an acrylic acid monomer for synthesizing a styrene-acrylic acid resin, for example, (meth) acrylic acid, (meth) acrylonitrile, (meth) acrylic acid alkyl ester, or (meth) acrylic acid hydroxyalkyl ester is preferable. . Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, iso-butyl (meth) acrylate, or 2-ethylhexyl (meth) acrylate is preferred. Examples of the (meth) acrylic acid hydroxyalkyl ester include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or (meth) acrylic acid 4 -Hydroxybutyl is preferred.

  When a styrene-acrylic acid resin is synthesized, a hydroxyl group can be introduced into the styrene-acrylic acid resin by using a monomer having a hydroxyl group. Moreover, the hydroxyl value of the styrene-acrylic acid-type resin obtained can be adjusted by adjusting the usage-amount of the monomer which has a hydroxyl group. As the monomer having a hydroxyl group, for example, p-hydroxystyrene, m-hydroxystyrene, or (meth) acrylic acid hydroxyalkyl ester can be used.

  When synthesizing a styrene-acrylic acid resin, a carboxyl group can be introduced into the styrene-acrylic acid resin by using an acrylic acid monomer having a carboxyl group. Moreover, the acid value of the styrene-acrylic acid-type resin obtained can be adjusted by adjusting the usage-amount of (meth) acrylic acid.

(Binder resin: Polyester resin)
The polyester resin is obtained by polycondensing one or more alcohols and one or more carboxylic acids. As the alcohol for synthesizing the polyester resin, for example, the following dihydric alcohol or trihydric or higher alcohol can be suitably used. As the dihydric alcohol, for example, diols or bisphenols can be used. As the carboxylic acid for synthesizing the polyester resin, for example, the following divalent carboxylic acids or trivalent or higher carboxylic acids can be suitably used.

  Preferable examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4. -Diol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.

  Preferable examples of the bisphenol include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, or bisphenol A propylene oxide adduct.

  Preferable examples of trihydric or higher alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, or 1,3,5- Trihydroxymethylbenzene is mentioned.

  As preferable examples of the divalent carboxylic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid Succinic acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, etc.), or alkenyl succinic acid (more specific Specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, or isododecenyl succinic acid, etc.) may be mentioned.

  Preferred examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, or empole trimer acid.

(Toner core: Colorant)
As the colorant, a known pigment or dye can be used according to the color of the toner. In order to form a high-quality image using toner, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

  The toner core may contain a black colorant. An example of a black colorant is carbon black. The black colorant may be a colorant that is toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

  The toner core may contain a color colorant such as a yellow colorant, a magenta colorant, or a cyan colorant.

  As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155 168, 174, 175, 176, 180, 181, 191, or 194), naphthol yellow S, Hansa yellow G, or C.I. I. Vat yellow can be preferably used.

  The magenta colorant is, for example, selected from the group consisting of condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. One or more compounds can be used. Examples of the magenta colorant include C.I. I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 184, 185, 202, 206, 220, 221 or 254) can be preferably used.

  As the cyan colorant, for example, one or more compounds selected from the group consisting of a copper phthalocyanine compound, an anthraquinone compound, and a basic dye lake compound can be used. Examples of cyan colorants include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, or 66), phthalocyanine blue, C.I. I. Bat Blue, or C.I. I. Acid blue can be preferably used.

(Toner core: Release agent)
The release agent is used, for example, for the purpose of improving the fixing property or offset resistance of the toner. In order to increase the anionicity of the toner core, it is preferable to produce the toner core using an anionic wax. In order to improve the fixing property or offset resistance of the toner, the amount of the release agent is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

  Examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, or aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxidized polyethylene wax or a block thereof Oxides of aliphatic hydrocarbon waxes such as copolymers; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, or rice wax; animal properties such as beeswax, lanolin, or whale wax Waxes; mineral waxes such as ozokerite, ceresin, or petrolatum; waxes based on fatty acid esters such as montanate ester wax or castor wax; fats such as deoxidized carnauba wax The wax portion of the ester or the whole was deoxygenated can be suitably used. One type of release agent may be used alone, or multiple types of release agents may be used in combination.

  In order to improve the compatibility between the binder resin and the release agent, a compatibilizer may be added to the toner core.

(Toner core: charge control agent)
The charge control agent is used, for example, for the purpose of improving the charge stability or charge rising property of the toner. The charge rising characteristic of the toner is an index as to whether or not the toner can be charged to a predetermined charge level in a short time.

  By adding a negatively chargeable charge control agent to the toner core, the anionicity of the toner core can be enhanced. Further, the cationic property of the toner core can be increased by including a positively chargeable charge control agent in the toner core. However, if sufficient chargeability is ensured in the toner, it is not necessary to include a charge control agent in the toner core.

(Toner core: magnetic powder)
As the material of the magnetic powder, for example, a ferromagnetic metal or an alloy thereof, a ferromagnetic metal oxide, or a material subjected to ferromagnetization treatment can be preferably used. For example, iron, cobalt, or nickel can be used as the ferromagnetic metal. As the ferromagnetic metal oxide, for example, ferrite, magnetite, or chromium dioxide can be used. Examples of the ferromagnetization treatment include heat treatment. One type of magnetic powder may be used alone, or a plurality of types of magnetic powder may be used in combination.

  In order to suppress elution of metal ions (for example, iron ions) from the magnetic powder, it is preferable to surface-treat the magnetic powder. When a shell layer is formed on the surface of the toner core under acidic conditions, if the metal ions are eluted on the surface of the toner core, the toner cores are easily fixed to each other. It is considered that fixing of the toner cores can be suppressed by suppressing elution of metal ions from the magnetic powder.

(Toner mother particles: shell layer)
The shell layer is substantially composed of a resin. For example, by covering a core that melts at a low temperature with a shell layer having excellent heat resistance, it is possible to achieve both heat-resistant storage stability of the toner and low-temperature fixability of the toner. Additives may be dispersed in the resin constituting the shell layer. The shell layer may cover the entire surface of the core, or may partially cover the surface of the core.

  The resin contained in the shell layer and the thermosetting resin contained in the external additive coating layer are preferably polymers of different monomers. The resin contained in the shell layer and the thermosetting resin contained in the sleeve coat layer are preferably polymers of different monomers. If these are satisfied, the resin contained in the shell layer may be a thermoplastic resin or a mixture of a thermoplastic resin and a thermosetting resin.

  When each of the thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer has positive chargeability, examples of the thermoplastic resin contained in the shell layer include polyester resins and urethanes. Resin or acrylic resin is mentioned. In this case, examples of the thermosetting resin contained in the shell layer include a phenol resin, a silicone resin, and an epoxy resin.

  When each of the thermosetting resin contained in the external additive coat layer and the thermosetting resin contained in the sleeve coat layer has negative chargeability, the thermoplastic resin contained in the shell layer includes, for example, a polyamide resin. It is done. In this case, examples of the thermosetting resin contained in the shell layer include melamine resin and urea resin.

  In order to improve the film quality of the shell layer, the resin contained in the shell layer is derived from 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, or 2-hydroxypropyl methacrylate. One or more alcoholic hydroxyl groups may be introduced.

[Example of toner application]
The toner according to the exemplary embodiment can be suitably used for developing an electrostatic latent image, for example, as a positively chargeable toner. The toner according to this exemplary embodiment may be used as a one-component developer or may be used as a toner contained in a two-component developer.

(Two-component developer)
When the toner according to this embodiment is used as a toner contained in a two-component developer, the two-component developer can be prepared by mixing the toner and the carrier using a mixing device. As the mixing device, for example, a ball mill can be used.

  It is preferable to use a ferrite carrier as the carrier. Thereby, a high quality image can be formed. As the carrier, it is more preferable to use magnetic carrier particles including a carrier core and a resin layer covering the carrier core. Thereby, a high-quality image can be formed over a long period of time. In order to impart magnetism to the carrier particles, the carrier particles may be formed of a magnetic material, or the carrier particles may be formed of a resin in which the magnetic particles are dispersed. Further, magnetic particles may be dispersed in the resin layer covering the carrier core. In order to form a high-quality image, the amount of toner in the two-component developer is preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the carrier. The positively chargeable toner contained in the two-component developer is positively charged by friction with the carrier.

  Examples of the present invention will be described. Table 1 shows image forming apparatuses D-1 to D-9 according to Examples or Comparative Examples. Table 2 shows the material of the coat layer included in each image forming apparatus. Hereinafter, the image forming apparatuses D-1 to D-9 are referred to as apparatuses D-1 to D-9, respectively.

In Table 2, D ₅₀ mean, volume median diameter of the second external additive particles in volume median diameter of the first external additive particles in the first external additive, or the second external additive To do. In the coating layer material, the silane compound means that the silane compound is bonded to the surface of the silica particles in the first external additive, and the silane compound is bonded to the surface of the titanium oxide particles in the second external additive. Means that In the material of the coating layer, Ni / Cr means that a Cr electroplating layer is formed on the Ni electroless plating layer.

  Hereinafter, a manufacturing method, an evaluation method, and an evaluation result of the devices D-1 to D-9 will be described in order. In the evaluation in which an error occurs, a considerable number of measurement values with sufficiently small errors are obtained, and the arithmetic average of the obtained measurement values is used as the evaluation value.

(1) Manufacturing method of apparatus D-1 In the installation mode of a monochrome printer ("ECOSYS (registered trademark) P2135dn" manufactured by Kyocera Document Solutions Co., Ltd.), toner T-1 obtained according to the following method is accommodated in the developing device. Set in the department. Further, the developing roller RA obtained according to the method described below was attached to a monochrome printer. In this way, device D-1 was obtained.

[Production Method of Toner T-1]
(Preparation of toner mother particles Tp-A)
Using an FM mixer (“FM-10” manufactured by Nippon Coke Industries, Ltd.), 100 parts by mass of an amorphous resin (“Polyester (registered trademark) HP-313” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 6 Part by mass of carbon black (“MA100” manufactured by Mitsubishi Chemical Corporation), 2 parts by mass of the first charge control agent (Nigrosine dye, “BONTRON (registered trademark) N-71” manufactured by Orient Chemical Industries, Ltd.), 4 2 parts by mass of a second charge control agent (“Acrybase (registered trademark) FCA-201PS” manufactured by Fujikura Kasei Co., Ltd., component: a styrene-acrylic acid resin containing a repeating unit derived from a quaternary ammonium salt), and 4 masses Part of carnauba wax (manufactured by Toa Kasei Co., Ltd.) and a predetermined amount of magnetic powder (“TN-15” manufactured by Mitsui Mining & Smelting Co., Ltd.) were mixed. The mixing amount of the magnetic powder was 40 parts by mass with respect to 100 parts by mass of the mixture excluding the magnetic powder put in the FM mixer.

The obtained mixture was melt-kneaded using a twin-screw extruder (“TEM-26SS” manufactured by Toshiba Machine Co., Ltd.). Thereafter, the obtained kneaded material was cooled. The obtained kneaded material was coarsely pulverized with a set particle diameter of 2 mm using a pulverizer (“Rotoplex 16/8” manufactured by Toa Instruments Co., Ltd.). The obtained coarsely pulverized product was finely pulverized using a pulverizer (“Turbo Mill RS type” manufactured by Freund Turbo Co., Ltd.). The obtained finely pulverized product was classified using a classifier (“Elbow Jet EJ-LABO type” manufactured by Nippon Steel Mining Co., Ltd.). As a result, toner mother particles Tp-A having a volume median diameter (D ₅₀ ) of 7.0 μm were obtained.

(Preparation of first external additive Es-A)
Using a mixing apparatus (“TK Hibis Dispermix HM-3D-5” manufactured by PRIMIX Corporation), 500 mL of ion-exchanged water and 50 g of hydrophilic fumed silica particles (“AEROSIL manufactured by Nippon Aerosil Co., Ltd.) (Registered trademark) 200 ”, number average primary particle size: 12 nm, BET specific surface area: about 200 m ² / g). This agitation was performed at room temperature at a rotation speed of 30 rpm for 30 minutes. In this way, an aqueous dispersion of silica particles was obtained.

  To the obtained aqueous dispersion, 50 g of water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.) was added and stirred at room temperature for 5 minutes at a rotation speed of 30 rpm. The obtained mixture (contents of the mixing apparatus) was transferred to a separable flask (volume: 1 L) equipped with a thermometer and a stirring blade. While stirring the contents of the flask using a stirrer, the temperature was raised from 35 ° C. to 70 ° C. at a rate of 1 ° C./3 minutes. Thereafter, the contents of the flask were stirred under the stirring conditions of a temperature of 70 ° C., a rotation speed of 90 rpm, and a stirring time of 30 minutes. Thereby, the surface of the silica particles was covered with the coat layer. Thereafter, the contents of the flask were cooled to room temperature. In this way, a dispersion of the first external additive was obtained. In the stirrer used, a stirring blade (“R 1345” (propeller type stirring blade 4 blades) manufactured by IKA Japan Co., Ltd.) is attached to a motor (“As One Tornado Motor 1-5472-04” sold by As One Corporation). It was.

Using a Buchner funnel, the wet cake-like first external additive was recovered from the obtained dispersion liquid of the first external additive. The recovered first external additive was dispersed in an aqueous ethanol solution having a concentration of 50% by mass. The obtained slurry was put into a continuous surface reformer (“Coatmizer (registered trademark)” manufactured by Freund Sangyo Co., Ltd.), and the first external additive in the slurry was dried. In this way, a coarse powder of the first external additive Es-A was obtained. The drying conditions of the slurry using the continuous surface reformer were a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min.

The obtained coarse powder of the first external additive Es-A was pulverized using a collision plate jet pulverizer (“IJT-2” manufactured by Nippon Pneumatic Industry Co., Ltd.). In the pulverization, a ceramic flat plate was used as the collision plate. The crushing pressure was set to 0.6 MPa. In this way, the first external additive Es-A was obtained. The obtained first external additive Es-A contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 21 nm. In this external additive particle, the coating layer formed on the surface of the silica particle contained a melamine resin and had a thickness of 3 nm.

(Preparation of second external additive Et-A)
Using a mixing device (“TK Hibis Dispermix HM-3D-5 type” manufactured by Primix Co., Ltd.), 500 mL of ion-exchanged water and 60 g of titanium oxide particles (rutile titanium oxide, number average primary particles) (Diameter: 200 nm). This agitation was performed at room temperature at a rotation speed of 30 rpm for 30 minutes. In this way, an aqueous dispersion of titanium oxide particles was obtained.

  To the obtained aqueous dispersion, 50 g of water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.) was added and stirred at room temperature for 5 minutes at a rotation speed of 30 rpm. The obtained mixture (contents of the mixing apparatus) was transferred to a separable flask (volume: 1 L) equipped with a thermometer and a stirring blade. While stirring the contents of the flask using a stirrer, the temperature was raised from 35 ° C. to 70 ° C. at a rate of 1 ° C./3 minutes. Thereafter, the contents of the flask were stirred under the stirring conditions of a temperature of 70 ° C., a rotation speed of 90 rpm, and a stirring time of 30 minutes. Thereby, the surface of the titanium oxide particles was covered with the coat layer. Thereafter, the contents of the flask were cooled to room temperature. In this way, a dispersion of the second external additive was obtained. In the stirrer used, a stirring blade (“R 1345” (propeller type stirring blade 4 blades) manufactured by IKA Japan Co., Ltd.) is attached to a motor (“As One Tornado Motor 1-5472-04” sold by As One Corporation). It was.

Using a Buchner funnel, the wet cake-like second external additive was recovered from the obtained dispersion liquid of the second external additive. The recovered second external additive was dispersed in an aqueous ethanol solution having a concentration of 50% by mass. The obtained slurry was put into a continuous surface reforming apparatus (“Coatmizer (registered trademark)” manufactured by Freund Sangyo Co., Ltd.), and the second external additive in the slurry was dried. In this way, a coarse powder of the second external additive Et-A was obtained. The drying conditions of the slurry using the continuous surface reformer were a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min.

The obtained coarse powder of the second external additive Et-A was pulverized using a collision plate jet pulverizer (“IJT-2” manufactured by Nippon Pneumatic Industry Co., Ltd.). In the pulverization, a ceramic flat plate was used as the collision plate. The crushing pressure was set to 0.6 MPa. In this way, a second external additive Et-A was obtained. The obtained second external additive Et-A contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 205 nm. In this external additive particle, the coat layer formed on the surface of the titanium oxide particle contained a melamine resin and had a thickness of 5 nm.

(External)
Using an FM mixer (“FM-10” manufactured by Nippon Coke Kogyo Co., Ltd.) at a rotational speed of 3500 rpm, 100 parts by mass of toner base particles Tp-A and 1.5 parts by mass of first external additive Es -A and 1.0 part by mass of the second external additive Et-A were mixed for 5 minutes. As a result, the first external additive Es-A and the second external additive Et-A adhered to the surface of the toner base particles Tp-A. Then, sieving was performed using a 300 mesh sieve (aperture 48 μm). As a result, Toner T-1 containing a large number of toner particles was obtained.

[Production Method for Developing Roller RA]
(Production of Silane Coupling Agent Sc-1)
Using a tabletop sand mill (manufactured by Hayashi Shoten Co., Ltd.), 10 parts by mass of a silane coupling agent (n-octyltriethoxysilane, “A-137” manufactured by Momentive Performance Materials) and 100 parts by mass of ethanol And were mixed for 3 hours. In this way, a silane coupling agent Sc-1 was obtained.

(surface treatment)
The sleeve of the developing roller was taken out from a monochrome printer (“ECOSYS (registered trademark) P2135dn” manufactured by Kyocera Document Solutions Inc.). The removed sleeve had a sleeve base made of aluminum. The surface of the sleeve base was blasted. That is, irregularities were formed on the surface of the sleeve base.

  Next, the surface of the taken-out sleeve was processed by the dip coating method using the silane coupling agent Sc-1. Thereafter, drying was performed with hot air at a temperature of 150 ° C. for 1 hour. As a result, a surface treatment layer (a layer containing the silane coupling agent Sc-1) having a thickness of 10 nm was formed on the surface of the sleeve base. Hereinafter, the developing roller on which the surface treatment layer is formed is referred to as a post-processing roll.

(Formation of coat layer)
Subsequently, the post-treatment roll was placed in an aqueous solution containing water-soluble methylol melamine (“Nika Resin (registered trademark) S-260” manufactured by Nippon Carbide Industries, Ltd.). The silane coupling agent Sc-1 and methylolmelamine in the surface treatment layer of the post-treatment roll were reacted at a temperature of 100 ° C. for 3 hours. After the treatment, the roll was taken out from the aqueous solution and washed. The surface layer part (resin) of the sleeve of the roll after treatment was cured and dried with hot air at a temperature of 120 ° C. Thereby, the silane coupling agent Sc-1 and methylol melamine existing on the surface of the surface treatment layer were bonded. As a result, a coat layer was formed on the surface layer portion of the sleeve of the post-treatment roll. The formed coating layer contained a melamine resin and had a thickness of 10 nm. In this way, a developing roller RA was obtained.

(2) Manufacturing method of apparatus D-2 Toner T-2 obtained according to the following method was used as the toner. Further, as a developing roller, a developing roller RB obtained according to the method shown below was used. Except for these, device D-2 was obtained according to the method for producing device D-1.

[Production Method of Toner T-2]
Toner T-2 was obtained according to the production method of toner T-1, except that the first external additive Es-B and the second external additive Et-B obtained according to the method described below were used.

(Preparation of first external additive Es-B)
Instead of water-soluble methylol melamine ("Nika Resin (registered trademark) S-260" manufactured by Nippon Carbide Industries Co., Ltd.), an aqueous solution of methylol urea ("Milben (registered trademark) Resin SU-100" manufactured by Showa Denko KK), solid content A concentration of 80% by mass) was used. Except this, according to the manufacturing method of 1st external additive Es-A, 1st external additive Es-B was obtained. The obtained first external additive Es-B contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 21 nm. In this external additive particle, the coating layer formed on the surface of the silica particle contained urea resin and had a thickness of 3 nm.

(Preparation of second external additive Et-B)
Instead of water-soluble methylol melamine ("Nika Resin (registered trademark) S-260" manufactured by Nippon Carbide Industries Co., Ltd.), an aqueous solution of methylol urea ("Milben (registered trademark) Resin SU-100" manufactured by Showa Denko KK), solid content A concentration of 80% by mass) was used. Except for this, the second external additive Et-B was obtained according to the method for producing the second external additive Et-A. The obtained second external additive Et-B contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 205 nm. In this external additive particle, the coat layer formed on the surface of the titanium oxide particle contained a urea resin and had a thickness of 5 nm.

[Production Method for Developing Roller RB]
The roll after the treatment is not an aqueous solution containing water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.), but an aqueous solution of methylol urea (“Milben® registered resin” manufactured by Showa Denko KK). SU-100 ", solid content concentration 80% by mass). Except for this, a developing roller RB was obtained according to the manufacturing method of the developing roller RA. In the obtained developing roller RB, a surface treatment layer and a coating layer were formed in this order on the surface of the sleeve base. The formed coating layer contained urea resin and had a thickness of 10 nm.

(3) Manufacturing method of apparatus D-3 Toner T-3 obtained according to the following method was used as the toner. Except for this, device D-3 was obtained according to the method for producing device D-1.

[Production Method of Toner T-3]
The toner T-3 was obtained by externally adding the first external additive Es-C and the second external additive Et-C to the toner base particles Tp-B. Hereinafter, the production methods of the toner base particles Tp-B, the first external additive Es-C, and the second external additive Et-C are sequentially shown.

(Preparation of toner mother particles Tp-B)
Toner base particles having a shell layer were prepared as toner base particles Tp-B.

(Production of toner core)
Using an FM mixer (“FM-10” manufactured by Nippon Coke Industries, Ltd.), 100 parts by mass of an amorphous resin (“Polyester (registered trademark) HP-313” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), 6 Part by mass of carbon black (“MA100” manufactured by Mitsubishi Chemical Corporation), 2 parts by mass of the first charge control agent (Nigrosine dye, “BONTRON (registered trademark) N-71” manufactured by Orient Chemical Industries, Ltd.), 4 2 parts by mass of a second charge control agent (“Acrybase (registered trademark) FCA-201PS” manufactured by Fujikura Kasei Co., Ltd., component: a styrene-acrylic acid resin containing a repeating unit derived from a quaternary ammonium salt), and 4 masses Part of carnauba wax (manufactured by Toa Kasei Co., Ltd.) and a predetermined amount of magnetic powder Y were mixed. The mixing amount of the magnetic powder Y was 40 parts by mass with respect to 100 parts by mass of the mixture excluding the magnetic powder Y put in the FM mixer.

Next, the obtained mixture was melt-kneaded using a twin-screw extruder (“TEM-26SS” manufactured by Toshiba Machine Co., Ltd.). Thereafter, the obtained kneaded material was cooled. The obtained kneaded material was coarsely pulverized with a set particle diameter of 2 mm using a pulverizer (“Rotoplex 16/8” manufactured by Toa Instruments Co., Ltd.). The obtained coarsely pulverized product was finely pulverized using a pulverizer (“Turbo Mill RS type” manufactured by Freund Turbo Co., Ltd.). The obtained finely pulverized product was classified using a classifier (“Elbow Jet EJ-LABO type” manufactured by Nippon Steel Mining Co., Ltd.). As a result, particles X having a volume median diameter (D ₅₀ ) of 7.0 μm were obtained.

  Using an FM mixer (“FM-10” manufactured by Nippon Coke Industries, Ltd.), 100 parts by mass of particles X and 2 parts by mass of magnetic powder Y were mixed at a rotational speed of 5000 rpm for 5 minutes. As a result, the magnetic powder Y was externally added to the particles X, and as a result, a toner core was obtained.

  Magnetic powder Y was produced according to the following method. First, 10 kg of magnetite powder (“TN-15” manufactured by Mitsui Mining & Smelting Co., Ltd.) was immersed in 20 L of an ethyl silicate solution (solution having an ethyl silicate concentration of 100 mass%). After 5 minutes, the magnetite powder was removed. The extracted magnetite powder was heated under reduced pressure and 230 ° C. for 30 minutes. In this way, magnetic powder Y was obtained. In the obtained magnetic powder Y, a silica film was formed on the surface of the magnetite powder.

(Shell layer)
A three-necked flask (capacity: 1 L) was placed in a water bath adjusted to 30 ° C. (Aswan Co., Ltd. “IWB-250 type”). 300 mL of ion-exchanged water was placed in the three-necked flask, and the pH of the liquid in the three-necked flask was adjusted to 4 using hydrochloric acid. 2 mL of water-soluble methylol melamine (“Nika Resin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.)) is added to the liquid whose pH is adjusted to 4, and methylol melamine is dissolved in ion-exchanged water (pH: 4). It was. To the aqueous methylolmelamine solution thus obtained, 300 g of the toner core obtained according to the above-described method was added. While stirring the contents of the three-necked flask, 300 mL of ion-exchanged water was further added, and the temperature of the water bath was raised to 70 ° C. When the water bath temperature reached 70 ° C., the water bath temperature was held at 70 ° C. for 2 hours. After adjusting the pH of the contents of the three-necked flask to 7 using an aqueous sodium hydroxide solution (alkali), the solid matter in the three-necked flask was recovered by filtration. The collected solid was washed and dried. In this way, toner base particles Tp-B were obtained.

(Preparation of first external additive Es-C)
In a mixing device (“TK Hibis Dispermix HM-3D-5” manufactured by PRIMIX Corporation), 500 mL of toluene (“Toluene Class 1” manufactured by Wako Pure Chemical Industries, Ltd.) and 2 g of γ-aminopropyltriethoxy Silane was added and γ-aminopropyltriethoxysilane was dissolved in toluene. Next, 50 g of hydrophilic fumed silica particles (“AEROSIL (registered trademark) 200” manufactured by Nippon Aerosil Co., Ltd., number average primary particle size: 12 nm, BET specific surface area: about 200 m ² / g) are further added to the mixing device. Added and stirred. This agitation was performed at room temperature at a rotation speed of 30 rpm for 30 minutes.

  The obtained mixture (contents of the mixing apparatus) was transferred to a separable flask (volume: 1 L) equipped with a thermometer and a stirring blade. While stirring the contents of the flask using a stirrer, the temperature was raised from 35 ° C. to 70 ° C. at a rate of 1 ° C./3 minutes. Thereafter, the contents of the flask were stirred. In this stirring, the stirring device used when preparing the dispersion liquid of the first external additive in the above (Preparation of the first external additive Es-A) was used. Moreover, this stirring was performed under the stirring conditions when the dispersion liquid of the first external additive was prepared in the above (Preparation of the first external additive Es-A).

  Toluene was removed from the contents of the flask using a rotary evaporator. The solid material thus obtained was dried using a vacuum dryer. The set temperature of the vacuum dryer was 50 ° C. Also, this drying was performed until the mass of the solid material was not reduced. Thereafter, the obtained solid was heated at 200 ° C. for 3 hours using an electric furnace under a nitrogen stream. By this heating, the hydroxyl group present on the surface of the silica particles and the silane compound were bonded. This silane compound had an amino group at the terminal. In this way, a coarse powder of the first external additive Es-C was obtained.

The obtained coarse powder of the first external additive Es-C was pulverized. In this pulverization, the pulverizer used when pulverizing the coarse powder of the first external additive Es-A in the above (production of the first external additive Es-A) was used. In addition, the pulverization was performed under the pulverization conditions when the coarse powder of the first external additive Es-A was pulverized in the above (production of the first external additive Es-A). In this way, the first external additive Es-C was obtained. The obtained first external additive Es-C contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 22 nm.

(Preparation of second external additive Et-C)
In a mixing device (“TK Hibis Disper Mix HM-3D-5” manufactured by PRIMIX Corporation), 500 mL of toluene (“Toluene Grade 1” manufactured by Wako Pure Chemical Industries, Ltd.) and 3 g of γ-aminopropyltriethoxy Silane was added and γ-aminopropyltriethoxysilane was dissolved in toluene. Next, 60 g of titanium oxide particles (rutile-type titanium oxide, number average primary particle size: 200 nm) were further added to the mixing apparatus and stirred. This agitation was performed at room temperature at a rotation speed of 30 rpm for 30 minutes.

  The obtained mixture (contents of the mixing apparatus) was transferred to a separable flask (volume: 1 L) equipped with a thermometer and a stirring blade. While stirring the contents of the flask using a stirrer, the temperature was raised from 35 ° C. to 70 ° C. at a rate of 1 ° C./3 minutes. Thereafter, the contents of the flask were stirred. In this stirring, the stirring device used when preparing the dispersion liquid of the second external additive in the above (Preparation of second external additive Et-A) was used. Moreover, this stirring was performed under the stirring conditions when the dispersion liquid of the second external additive was prepared in the above (Preparation of the second external additive Et-A).

  Toluene was removed from the contents of the flask using a rotary evaporator. The solid material thus obtained was dried using a vacuum dryer. The set temperature of the vacuum dryer was 50 ° C. Also, this drying was performed until the mass of the solid material was not reduced. Thereafter, the obtained solid was heated at 200 ° C. for 3 hours using an electric furnace under a nitrogen stream. By this heating, the hydroxyl group present on the surface of the titanium oxide particles was bonded to the silane compound. This silane compound had an amino group at the terminal. In this way, a coarse powder of the second external additive Et-C was obtained.

The obtained coarse powder of the second external additive Et-C was pulverized. In this pulverization, the pulverizer used when pulverizing the coarse powder of the second external additive Et-A in the above (production of the second external additive Et-A) was used. In addition, the pulverization was performed under the pulverization conditions when the coarse powder of the second external additive Et-A was pulverized in the above (production of the second external additive Et-A). In this way, a second external additive Et-C was obtained. The obtained second external additive Et-C contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 204 nm.

(4) Manufacturing method of apparatus D-4 Toner T-4 obtained according to the following method was used as the toner. Further, as a developing roller, a developing roller RC obtained according to the method shown below was used. Except for these, device D-4 was obtained according to the method for producing device D-1.

[Production Method of Toner T-4]
The toner T-4 was obtained by externally adding the first external additive Es-D and the second external additive Et-D to the toner base particles Tp-A. Below, each preparation method of 1st external additive Es-D and 2nd external additive Et-D is shown in order.

(Preparation of first external additive Es-D)
Instead of water-soluble methylol melamine ("Nika Resin (registered trademark) S-260" manufactured by Nippon Carbide Industries Co., Ltd.), an aqueous solution of urethane resin ("Superflex (registered trademark) 170" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), solid content A concentration of 30% by mass) was used. Except this, according to the manufacturing method of 1st external additive Es-A, 1st external additive Es-D was obtained. The obtained first external additive Es-D contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 21 nm. In this external additive particle, the coat layer formed on the surface of the silica particle contained a urethane resin and had a thickness of 3 nm.

(Preparation of second external additive Et-D)
Instead of water-soluble methylol melamine ("Nika Resin (registered trademark) S-260" manufactured by Nippon Carbide Industries Co., Ltd.), an aqueous solution of urethane resin ("Superflex (registered trademark) 170" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), solid content A concentration of 30% by mass) was used. Except for this, the second external additive Et-D was obtained according to the method for producing the second external additive Et-A. The obtained second external additive Et-D contained a plurality of external additive particles having a volume median diameter (D ₅₀ ) of 205 nm. In this external additive particle, the coat layer formed on the surface of the titanium oxide particle contained a urethane resin and had a thickness of 5 nm.

[Production Method for Developing Roller RC]
The roll after the treatment is not an aqueous solution containing water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.) but an aqueous solution of urethane resin (“Superflex (registered trademark) manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Trademark) 170 ", solid content concentration 30% by mass). Except for this, a developing roller RC was obtained according to the method for producing the developing roller RA. In the obtained developing roller RC, a surface treatment layer and a coat layer were formed in this order on the surface of the sleeve base. The formed coating layer contained a urethane resin and had a thickness of 10 nm.

(5) Manufacturing method of apparatus D-5 Toner T-5 obtained according to the following method was used as the toner. Further, as a developing roller, a developing roller RD obtained according to the method shown below was used. Except for these, device D-5 was obtained according to the method for producing device D-1.

[Production Method of Toner T-5]
The toner T-5 was obtained by externally adding the first external additive Es-C and the second external additive Et-C to the toner base particles Tp-A.

[Method for Manufacturing Developing Roller RD]
The post-treatment roll is not an aqueous solution containing water-soluble methylol melamine (“Nikaresin (registered trademark) S-260” manufactured by Nippon Carbide Industries Co., Ltd.), but an aqueous solution of phenol resin (“HP-710” manufactured by DIC Corporation, solid content) The concentration was 73 mass%). Except this, according to the manufacturing method of developing roller RA, developing roller RD was obtained. In the obtained developing roller RD, a surface treatment layer and a coat layer were formed in this order on the surface of the sleeve base. The formed coating layer contained a phenol resin and had a thickness of 10 nm.

(6) Manufacturing method of apparatus D-6 Except having used developing roller RD as a developing roller, apparatus D-6 was obtained according to the manufacturing method of apparatus D-1.

(7) Manufacturing method of apparatus D-7 Except having used developing roller RC as a developing roller, apparatus D-7 was obtained according to the manufacturing method of apparatus D-1.

(8) Manufacturing method of apparatus D-8 As a developing roller, developing roller RE obtained according to the method shown below was used. Except this, apparatus D-8 was obtained according to the manufacturing method of apparatus D-1.

[Method for Manufacturing Developing Roller RE]
The sleeve of the developing roller was taken out from a monochrome printer (“ECOSYS (registered trademark) P2135dn” manufactured by Kyocera Document Solutions Inc.). The removed sleeve had a sleeve base made of aluminum, and the surface of the sleeve base was blasted.

  Plating treatment was performed on the surface of the sleeve taken out. Specifically, first, using a solution (plating solution) obtained by immersing Ni in a hypophosphorous acid aqueous solution, the surface of the sleeve base was applied for 15 minutes at a solution temperature of 85 to 95 ° C. and a pH of 4.5 to 5.5. Electroless plating was performed. As a result, an electroless plating layer was formed on the surface of the sleeve base. In the formed electroless plating layer, the Ni content was 90% by mass and the P content was 10% by mass.

  Subsequently, the surface of the electroless plating layer was subjected to electrolytic plating treatment for 4 minutes under the conditions of a liquid temperature of 35 to 55 ° C., a pH of 3 to 4 and an applied voltage of 5 V using an electrolytic chromium plating solution. As a result, an electrolytic plating layer was formed on the surface of the electroless plating layer. The electrolytic plating layer contained trivalent Cr. In this way, a developing roller RE was obtained.

(9) Manufacturing method of apparatus D-9 Developing roller RF was used as the developing roller. The developing roller R-F was a developing roller included in a monochrome printer (“ECOSYS (registered trademark) P2135dn” manufactured by Kyocera Document Solutions Inc.). That is, the sleeve of the developing roller R-F has a sleeve base made of aluminum, and the surface of the sleeve base has been blasted. Except for these, device D-9 was obtained according to the method for producing device D-1.

[Measuring method]
(Thickness of the coating layer formed on the surface of the silica particles)
The thickness of the coating layer formed on the surface of the silica particles means the size of the coating layer in the particle size direction of the silica particles. First, a cross-sectional TEM photograph of silica particles was taken using a transmission electron microscope (TEM, “H-7100FA” manufactured by Hitachi High-Technologies Corporation). Next, a cross-sectional TEM photograph of the obtained silica particles was analyzed using image analysis software (“WinROOF” manufactured by Mitani Corporation). Specifically, two straight lines perpendicular to the approximate center of the cross section of the silica particles were drawn. In each of the two straight lines, the length from the interface between the silica particles and the coating layer (corresponding to the surface of the silica particles) to the surface of the coating layer was measured. The average value of the four lengths measured in this way was taken as the thickness of the coating layer formed on the surface of one silica particle. Such a measurement of the thickness of the coating layer was performed on a plurality of silica particles, and an average value of the thicknesses of the coating layers formed on the surfaces of the plurality of silica particles (measurement target) was obtained. The average value of the thickness of the coating layer thus determined was defined as “the thickness of the coating layer formed on the surface of the silica particles”.

  When the boundary between the silica particle and the coating layer is unclear in the cross-sectional TEM photograph of the silica particle, the cross-sectional TEM photograph of the silica particle is converted into an electron energy loss spectroscopy (EELS) detector (“GIF TRIDIEM” (registered by Gatan). Trademark) ”) and image analysis software (“ WinROOF ”manufactured by Mitani Corporation).

(Thickness of the coating layer formed on the surface of the titanium oxide particles)
The thickness of the coat layer formed on the surface of the titanium oxide particles means the size of the coat layer in the particle size direction of the titanium oxide particles. The thickness of the coat layer formed on the surface of the titanium oxide particles was measured according to the method described above (the thickness of the coat layer formed on the surface of the silica particles).

(Thickness of the surface treatment layer formed on the surface of the sleeve base)
The thickness of the surface treatment layer formed on the surface of the sleeve base was measured according to the method described above (thickness of the coat layer formed on the surface of the silica particles). Here, the thickness of the surface treatment layer formed on the surface of the sleeve base means the size of the surface treatment layer in a direction perpendicular to the surface of the sleeve base on which the surface treatment layer is formed.

  First, a cross-sectional TEM photograph of a sleeve was taken using a transmission electron microscope (TEM, “H-7100FA” manufactured by Hitachi High-Technologies Corporation). Next, a cross-sectional TEM photograph of the obtained sleeve was analyzed using image analysis software (“WinROOF” manufactured by Mitani Corporation). Specifically, two straight lines perpendicular to each other at the approximate center of the cross section of the sleeve were drawn. In each of the two straight lines, the length from the interface between the sleeve base and the surface treatment layer (corresponding to the surface of the sleeve base) to the surface of the surface treatment layer was measured. The average value of the four lengths thus measured was taken as the thickness (one location) of the surface treatment layer formed on the surface of the sleeve base. The thickness of the surface treatment layer was measured for a plurality of measurement points, and the average value of the thickness of the surface treatment layer at the plurality of measurement points was obtained. The average value of the thicknesses of the surface treatment layers thus determined was defined as “the thickness of the surface treatment layer formed on the surface of the sleeve substrate”. In addition, the measurement points are both end portions (portions close to the flange) and the central portion of the sleeve at each of the four rotation positions (angles 0 °, 90 °, 180 °, 270 °) of the developing roller, a total of 12 points. It was an area.

  When the boundary between the sleeve base and the surface treatment layer is unclear in the cross-sectional TEM photograph of the sleeve, the cross-sectional TEM photograph of the sleeve is converted into an electron energy loss spectroscopy (EELS) detector (“GIF TRIDIM (registered trademark)” manufactured by Gatan. ) ") And image analysis software (" WinROOF "manufactured by Mitani Corporation).

(Thickness of the coat layer formed on the surface layer of the sleeve)
In accordance with the method described above (thickness of the surface treatment layer formed on the surface of the sleeve substrate), the thickness of the coat layer formed on the surface layer portion of the sleeve was measured. Here, the thickness of the coat layer formed on the surface layer portion of the sleeve means the size of the coat layer in a direction perpendicular to the surface of the sleeve base on which the coat layer is formed.

  First, according to the method described above (the thickness of the surface treatment layer formed on the surface of the sleeve substrate), a cross-sectional TEM photograph of the sleeve was taken, and the obtained cross-sectional TEM photograph of the sleeve was analyzed. Specifically, two straight lines perpendicular to each other at the approximate center of the cross section of the sleeve were drawn. In each of the two straight lines, the length from the interface (corresponding to the surface of the surface treatment layer) between the surface treatment layer and the coat layer formed on the surface of the sleeve substrate to the surface of the coat layer was measured. The average value of the four lengths thus measured was taken as the thickness (one location) of the coat layer formed on the surface layer portion of the sleeve. Such a measurement of the thickness of the coat layer was performed on a plurality of measurement locations, and the average value of the thicknesses of the coat layers at the plurality of measurement locations was determined. The average value of the thicknesses of the coating layers thus determined was defined as “the thickness of the coating layer formed on the surface layer portion of the sleeve”. The measurement locations were all the same as the measurement locations described above (thickness of the surface treatment layer formed on the surface of the sleeve base).

  When the boundary between the surface treatment layer and the coating layer is unclear in the cross-sectional TEM photograph of the sleeve, the cross-sectional TEM photograph of the sleeve is converted into an electron energy loss spectroscopy (EELS) detector (“GIF TRIDIM (registered trademark)” manufactured by Gatan. ) ") And image analysis software (" WinROOF "manufactured by Mitani Corporation).

[Evaluation method]
Devices D-1 to D-9 (hereinafter referred to as target devices) were evaluated according to the following method. Using the target apparatus, a sample image with a printing rate of 8% was printed on one printing paper in an environment of a temperature of 20 ° C. and a humidity of 65% RH. Hereinafter, this printing is referred to as initial printing. Thereafter, the toner charge amount (initial), the toner transport amount (initial), the development unevenness (initial), and the adhesion force of the toner particles to the sleeve surface (initial) were evaluated. Hereinafter, the adhesion force of toner particles to the sleeve surface is referred to as adhesion force of toner particles.

  Using the target apparatus, a sample image with a printing rate of 8% was continuously printed on 100,000 sheets of printing paper in an environment of a temperature of 20 ° C. and a humidity of 65% RH. Hereinafter, this printing is referred to as printing durability. Thereafter, toner charge amount (after printing), toner transport amount (after printing), image density (after printing), uneven development (after printing), toner particle adhesion (after printing), and sleeve surface The state of wear (after printing) was evaluated.

(Toner charge amount, toner transport amount)
The toner charge amount (initial, after printing) and the toner transport amount (initial, after printing) were evaluated according to the following methods. First, after each of initial printing and printing durability, the developing device was taken out from the target device. Next, using a suction pump, toner was sucked from an arbitrary portion of the toner layer formed on the sleeve surface that was exposed from the developing device. Specifically, the toner was sucked with a nozzle attached to the suction pump. Then, using the sucked toner, the toner charge amount (initial, after printing durability) and the toner transport amount (initial, after printing durability) were measured.

First, the toner charge amount was measured. Specifically, the total amount of electricity of the sucked toner was measured using a Q / m meter. Further, the mass of the nozzle of the suction pump before suction and the mass of the nozzle of the suction pump after suction were measured. The mass of the sucked toner was calculated by subtracting the mass of the nozzle of the suction pump before suction from the mass of the nozzle of the suction pump after suction. Then, the toner charge amount (μC / g) was calculated using the following formula.
[Toner charge amount (μC / g)] = [Total electric amount of attracted toner (μC)] / [Mass of attracted toner (g)]

  If each toner charge amount (initial, after printing durability) was 4 μC / g or more and 7 μC / g or less, it was judged as good (◯). If each toner charge amount (initial, after printing durability) was less than 4 μC / g or more than 7 μC / g, it was judged as bad (×). The results are shown in Table 3.

Next, the toner conveyance amount was measured. Specifically, the mass of the collected toner was calculated according to a method for calculating the mass of the toner when the toner charge amount was measured. Then, the toner conveyance amount (mg / cm ² ) was calculated using the following formula. The area where the toner was collected was about 5 cm ² (about 0.8 cm × about 6.5 cm).
[Toner transport amount (mg / cm ² )] = [Mass of sucked toner (mg)] / [Area where toner is collected (cm ² )]

If each toner transport amount (initial, after printing durability) was 0.90 mg / cm ² or more and 1.10 mg / cm ² or less, it was judged as good (◯). If each of the toner transport amounts (initial, after printing) exceeded 1.10 mg / cm ² , it was judged as bad (×). The results are shown in Table 3.

(Image density)
The image density (initial, after printing) was evaluated according to the following method. First, the image density (initial) was measured. Specifically, a sample image (including a solid image portion) for image density measurement was printed on one sheet of printing paper in an environment of a temperature of 20 ° C. and a humidity of 65% RH using the target apparatus. Thereafter, using a Macbeth reflection densitometer (“RD914” manufactured by X-Rite), the reflection density (ID: image density) of the solid image portion of the printed paper after printing (solid image portion of the formed sample image) is determined. It was measured. In this way, the image density (initial) was measured.

  Next, the image density (after printing) was measured. Specifically, after printing, a sample image (including a solid image portion) for image density measurement was printed on one sheet of printing paper using the target apparatus. Thereafter, using a Macbeth reflection densitometer (“RD914” manufactured by X-Rite), the reflection density (ID: image density) of the solid image portion of the printed paper after printing (solid image portion of the formed sample image) is determined. It was measured. In this way, the image density (after printing) was measured.

  If each of the image density (ID) (initial, after printing) was 1.30 or more, it was evaluated as ◯ (good). If each of image density (ID) (initial, after printing) was 1.20 or more and less than 1.30, it was evaluated as Δ (normal). When each image density (ID) (initial, after printing) was less than 1.20, it was evaluated as x (bad). The results are shown in Table 3.

(Development unevenness)
Development unevenness (initial, after printing) was evaluated according to the following methods. First, after each of the initial printing and printing durability, a half image having a printing rate of 50% was printed using the target apparatus. The presence or absence of density unevenness in the printed half-image was confirmed visually. When it was not confirmed that the density unevenness existed at the same interval as the sleeve diameter in the entire half image, it was evaluated as “good”. When it was confirmed that density unevenness was present at the same interval as the sleeve diameter in the entire half image, it was evaluated as x (bad). The results are shown in Table 4.

(Adhesion of toner particles)
The adhesion of toner particles (initial, after printing) was evaluated according to the following methods. First, after each of initial printing and printing durability, the developing roller was taken out from the target device. Next, each of the adhesion force of the toner particles (initial and after printing durability) was measured using an apparatus for measuring adhesion between fine particles (“Contact Re PAF-300N” manufactured by Okada Seiko Co., Ltd.).

  Specifically, the tip of the contact needle of the microparticle adhesion measuring apparatus was brought into contact with the toner particles adhering to the sleeve surface of the developing roller. Thereafter, the contact needle of the microparticle adhesion measuring apparatus was moved away from the sleeve surface until the toner particles detached from the sleeve surface. Then, the adhesive force between the sleeve surface and the toner particles immediately before the toner particles were detached from the sleeve surface was measured. The measured adhesive force was defined as the adhesive force of the toner particles (initial, after printing).

  If each of the adhesion of toner particles (initial, after printing durability) was 10 nN or less, it was evaluated as ◯ (good). If each of the adhesion force (initial, after printing durability) of the toner particles is more than 10 nN and 20 nN or less, it is evaluated as Δ (normal). If each of the toner particle adhesion (initial and after printing) exceeded 20 nN, it was evaluated as x (bad). The results are shown in Table 4.

(Wear surface of sleeve)
The wear state (initial, after printing) of the sleeve surface was evaluated according to the following methods. Note that the worn state (initial) of the sleeve surface means the worn state of the sleeve surface before the toner is set in the housing portion of the developing device.

  First, the developing roller was taken out from the target device before the toner was set in the accommodating portion of the developing device and after printing. The developing roller taken out after printing was pretreated. Specifically, gas was blown onto the sleeve surface to remove toner particles adhering to the sleeve surface. Thereafter, the sleeve surface to which the gas was sprayed was washed with alcohol.

  Next, the developing roller was set on a surface roughness shape measuring machine (“SURFCOM (registered trademark) 590A” manufactured by Tokyo Seimitsu Co., Ltd.). This measuring machine was equipped with a measuring probe having a tip radius of 2 μm. The ten-point average surface roughness was measured under the conditions of a measurement length of 24 mm, a cutoff wavelength of 0.8 mm, and a cutoff type Gaussian. The measurement points are the two end portions (portions close to the flange) and the central portion of the sleeve at each of the four rotation positions (angles 0 °, 90 °, 180 °, 270 °) of the developing roller, and a total of 12 regions. Met. The ten-point average surface roughness in each region was measured according to the method for measuring the ten-point average surface roughness Rzjis in “JIS B0601”. The arithmetic average of the 12 measured values (each 10-point average surface roughness) was defined as the average surface roughness of the sleeve (initial, after printing).

  When each of the average surface roughness (initial, after printing) of the sleeve was 7.0 μm or more and 7.5 μm or less, it was evaluated as “good”. If each of the average surface roughness (initial, after printing) of the sleeve was less than 7.0 μm, it was evaluated as x (bad). The results are shown in Table 4.

[Evaluation results]
Tables 3 and 4 show the evaluation results of the devices D-1 to D-9. Table 3 shows the evaluation results of the toner charge amount (initial, after printing durability), the toner transport amount (initial, after printing durability), and the image density (initial, after printing durability). Table 4 shows the evaluation results of development unevenness (initial, after printing), toner particle adhesion (initial, after printing), and sleeve surface wear (initial, after printing). . In addition, in each of Table 3 and Table 4, the numerical value represents the measurement result.

  The devices D-1 to D-2 (image forming apparatuses according to Examples 1 and 2) each had the above-described basic configuration. Specifically, each of the devices D-1 to D-2 includes a developing device configured to develop the electrostatic latent image with toner. The developing device includes a storage unit that stores toner, and a toner carrier that carries the toner supplied from the storage unit. The toner carrier has a shaft and a sleeve rotatable around the shaft. The sleeve had a sleeve base and a sleeve coat layer formed on the surface of the sleeve base. The toner contained a plurality of toner particles each including toner mother particles and a plurality of external additive particles each attached to the surface of the toner mother particles. The external additive particles had an external additive core and an external additive coating layer formed on the surface of the external additive core. Each of the external additive coat layer and the sleeve coat layer contained a thermosetting resin. The thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer were polymers of the same monomers.

  As shown in Tables 3 and 4, in each of the devices D-1 to D-2, the toner charge amount, the toner transport amount, and the image density (ID) are maintained even after printing, and the development unevenness is prevented. Occurrence was suppressed, adhesion of toner particles was suppressed, and wear on the sleeve surface was suppressed.

  On the other hand, in the apparatus D-3 (image forming apparatus according to Comparative Example 1), compared with the apparatuses D-1 to D-2, the toner conveyance amount, the image density (ID), the development unevenness, and the adhesion force of the toner particles. It was inferior in each evaluation. Specifically, after printing, the toner conveyance amount increased, the image density (ID) decreased, development unevenness occurred, and the toner particle adhesion increased. The reason why such a result is obtained is considered as follows. In the first external additive, the hydroxyl group present on the surface of the silica particles and the silane compound were bonded, and in the second external additive, the hydroxyl group present on the surface of the titanium oxide particle was bonded to the silane compound. On the other hand, the coating layer of the developing roller was made of melamine resin.

  The apparatus D-4 (image forming apparatus according to Comparative Example 2) was inferior in all evaluations as compared with the apparatuses D-1 to D-2. Specifically, the toner charge amount and the image density (ID) decreased after the initial printing. Further, after printing, the toner transport amount increased, development unevenness occurred, the adhesion of toner particles increased, and the sleeve surface of the developing roller was worn. The reason why such a result is obtained is that each of the first external additive coat layer, the second external additive coat layer, and the developing roller coat layer is made of a urethane resin. Note that the urethane resin is a kind of thermoplastic resin.

  In the apparatus D-5 (image forming apparatus according to Comparative Example 3), all the evaluations except the evaluation of the sleeve surface wear state were inferior to the apparatuses D-1 to D-2. Specifically, after printing, the toner charge amount and toner transport amount increased, the image density (ID) decreased, and development unevenness occurred. Further, the adhesion force of the toner particles was too high even after the initial printing. The reason why such a result is obtained is considered as follows. In the first external additive, the hydroxyl group and amino group present on the surface of the silica particles were bonded, and in the second external additive, the hydroxyl group and amino group present on the surface of the titanium oxide particle were bonded. On the other hand, the coating layer of the developing roller was made of a phenol resin. The phenolic resin is considered to have negative chargeability.

  In the apparatus D-6 (image forming apparatus according to Comparative Example 4), all the evaluations except the evaluation of the wear state of the sleeve surface were inferior to the apparatuses D-1 to D-2. Specifically, after printing, the toner charge amount and toner transport amount increased, the image density (ID) decreased, and development unevenness occurred. Further, the adhesion force of the toner particles was too high even after the initial printing. The reason why such a result was obtained is that each coating layer of the first external additive and the second external additive is made of melamine resin, whereas the coating layer of the developing roller is made of phenol resin. It is done.

  The device D-7 (image forming device according to Comparative Example 5) was inferior in all evaluations compared to the devices D-1 to D-2. Specifically, after printing, the toner charge amount and toner transport amount increased, development unevenness occurred, and the sleeve surface was worn. Even after the initial printing, the image density (ID) was low, and the adhesion of the toner particles was too high. The reason why such a result was obtained is that each coating layer of the first external additive and the second external additive is made of melamine resin, whereas the coating layer of the developing roller is made of urethane resin. It is done.

  The devices D-8 to D-9 (image forming devices according to Comparative Examples 6 to 7) were inferior in all evaluations compared to the devices D-1 to D-2. Specifically, after printing, the toner charge amount and toner transport amount increased, the image density (ID) decreased, development unevenness occurred, and the sleeve surface was worn. Further, the adhesion force of the toner particles was too high even after the initial printing. The reason why such a result is obtained is considered as follows. In the apparatus D-8, the coating layer of the developing roller was a plating layer (Ni / Cr). In the apparatus D-9, no coat layer was formed on the surface of the sleeve base of the developing roller.

  The inventor has confirmed the following using a negatively chargeable toner. If each of the coating layer of the first external additive, the coating layer of the second external additive, and the coating layer of the developing roller is made of a phenol resin, the toner charge amount, the toner transport amount, and the image density even after printing durability (ID) was maintained, development unevenness was suppressed, toner particle adhesion was suppressed low, and sleeve surface wear was suppressed.

  The image forming apparatus according to the present invention can be used for forming an image in, for example, a copying machine, a printer, or a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Developing apparatus 10 Developing roller 11 Shaft 12 Magnet roll 13 Sleeve 13a Flange part 13b Flange part 20 Photoconductor drum 21 Charging apparatus 22 Exposure apparatus 23 Cleaning member 30 Toner charging member 40 Toner supply roller 60 Toner particle 61 Toner base particle 62 External addition Agent particle 130 Sleeve base 131 Surface treatment layer 132 Sleeve coat layer 610 Toner core 611 Shell layer 620 External additive core 622 External additive coat layer

Claims (7)

An image forming apparatus comprising a developing device configured to develop an electrostatic latent image with toner,
The developing device includes a storage unit that stores the toner, and a toner carrier that carries the toner supplied from the storage unit,
The toner carrier has a shaft and a sleeve rotatable around the shaft,
The sleeve has a sleeve base and a sleeve coat layer formed on the surface of the sleeve base,
The toner includes a plurality of toner particles each including toner mother particles and a plurality of external additive particles attached to the surface of the toner mother particles,
The external additive particles have an external additive core and an external additive coating layer formed on the surface of the external additive core,
The external additive coat layer and the sleeve coat layer each contain a thermosetting resin,
The image forming apparatus, wherein the thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are polymers of the same monomers. Unevenness is formed on the surface of the sleeve base,
The image forming apparatus according to claim 1, wherein unevenness corresponding to the unevenness formed on the surface of the sleeve base is formed on the surface of the sleeve coat layer. The sleeve has a surface treatment layer containing a coupling agent between the sleeve base and the sleeve coat layer,
The image forming apparatus according to claim 2, wherein the surface treatment layer is formed on a portion of the surface of the sleeve base where the irregularities are formed. The toner base particles have a toner core and a shell layer formed on the surface of the toner core;
The shell layer contains a resin,
The resin contained in the shell layer and the thermosetting resin contained in the external additive coating layer are polymers of different monomers.
The image forming apparatus according to claim 1, wherein the resin contained in the shell layer and the thermosetting resin contained in the sleeve coat layer are polymers of different monomers. The toner is a positively chargeable toner,
The thermosetting resin contained in the external additive coat layer and the thermosetting resin contained in the sleeve coat layer are each a polymer of a monomer containing a nitrogen atom in the chemical structure. 5. The image forming apparatus according to claim 4.   The image forming apparatus according to claim 5, wherein the thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are each a melamine resin.   The image forming apparatus according to claim 5, wherein the thermosetting resin contained in the external additive coating layer and the thermosetting resin contained in the sleeve coating layer are each a urea resin.

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