JP6610578B2 - Toner cartridge set and image forming apparatus - Google Patents

Description

  The present invention relates to a toner cartridge set, an image forming apparatus, and an image forming method.

  As an image forming method for forming an image on a transfer medium such as paper, an intermediate transfer system using a belt-shaped intermediate transfer medium is known. In the intermediate transfer system, a development process, a primary transfer process for transferring to the intermediate transfer body, a secondary transfer process for transferring to the transfer target, and a fixing process for fixing the toner image are performed on the transfer target. An image is formed on. When forming a color image by the intermediate transfer method, in the developing process, the electrostatic latent image formed on each photosensitive drum provided for each color is developed with a developer, and a toner image is formed on each photosensitive drum. Form. In the primary transfer step, a plurality of toner images are superimposed on the intermediate transfer member by sequentially transferring the toner images formed on the respective photosensitive drums to the intermediate transfer member. In the secondary transfer process, the toner images superimposed on the intermediate transfer member are collectively transferred to the transfer target. In the fixing step, the unfixed toner image transferred to the transfer target is fixed to the transfer target with a heating roller or the like.

  When primary transfer is performed in which a plurality of toner images are superimposed on the intermediate transfer member, a transfer bias is applied to the intermediate transfer member by the transfer unit. Therefore, each time the toner image of each color is transferred, The amount of toner charge increases. As a result, secondary transfer failure such as transfer scattering (toner scattering) in the secondary transfer process due to variations in the charge amount due to the difference in the number of primary transfers in the toner image on the intermediate transfer member, or electrostatic in the fixing process. Fixing failure such as offset may be caused.

  In order to suppress such secondary transfer failure and fixing failure, in the image forming apparatus described in Patent Document 1, a pre-transfer charger is provided in the vicinity of the intermediate transfer member to control the toner charge amount.

Japanese Patent Laid-Open No. 11-305566

  However, in the image forming apparatus disclosed in Patent Document 1, the provision of the pre-transfer charger leads to a complicated configuration and high cost of the image forming apparatus.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a toner cartridge capable of suppressing secondary transfer failure and fixing failure due to variations in the charge amount of toner without complicating the configuration of the image forming apparatus as much as possible. It is an object to provide a set, an image forming apparatus, and an image forming method.

  The toner cartridge set according to the present invention is used in an image forming apparatus that sequentially transfers a plurality of color toner images to an intermediate transfer member. The toner cartridge set according to the present invention has a plurality of toner cartridges for each color. Each of the toner cartridges includes a toner container and toner that is accommodated in the toner container and forms the toner image. The later the toner image is transferred, the higher the chargeability of the corresponding inner wall of the toner container.

  An image forming apparatus according to the present invention is an image forming apparatus that sequentially transfers a plurality of color toner images to an intermediate transfer member. The image forming apparatus according to the present invention has a plurality of toner cartridges for each color. Each of the toner cartridges includes a toner container and toner that is accommodated in the toner container and forms the toner image. The later the toner image is transferred, the higher the chargeability of the corresponding inner wall of the toner container.

  The image forming method according to the present invention includes a primary transfer process and a secondary transfer process. In the primary transfer step, toner images of a plurality of colors are sequentially transferred onto the intermediate transfer member using a plurality of toner cartridges for each color. In the secondary transfer step, the toner image transferred to the intermediate transfer member is transferred to the transfer target. Each of the toner cartridges includes a toner container and toner that is accommodated in the toner container and forms the toner image. The inner walls of the toner containers have different charging properties. In the primary transfer step, the toner images are sequentially transferred from the toner image formed using the toner of the toner cartridge having a smaller chargeability of the inner wall of the toner container.

  According to the present invention, a toner cartridge set, an image forming apparatus, and an image formation that can suppress a secondary transfer failure and a fixing failure due to a variation in toner charge amount without complicating the configuration of the image forming apparatus as much as possible. Can provide a method.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a toner cartridge in the image forming apparatus according to the present embodiment.

Preferred embodiments of the present invention will be described in detail. In the following description, chargeability means chargeability in frictional charging unless otherwise specified. The strength of positive chargeability (or strength of negative chargeability) in frictional charging can be confirmed by a known charge train or the like. The strength of the charging property corresponds to the ease of frictional charging unless otherwise specified. For example, the toner can be triboelectrically charged by mixing with a standard carrier provided by the Imaging Society of Japan and stirring. The surface potential of the toner particles is measured with, for example, KFM (Kelvin probe force microscope) before and after the frictional charging, and the portion having a larger potential change before and after the frictional charging has a higher charging property. The magnitude of the charge amount indicates the magnitude of the absolute value of the charge amount unless otherwise specified. Moreover, the measured value of the volume median diameter (D ₅₀ ) of the powder is not specified, and the “Coulter counter multisizer 3” manufactured by Beckman Coulter Co., Ltd. is used. ) Measured based on.

  In the following description, a compound and its derivative 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. In this specification, untreated silica particles and particles obtained by subjecting untreated silica particles to surface treatment are also referred to as “silica particles”. In addition, silica particles hydrophobized with a surface treatment agent may be described as hydrophobic silica particles.

  A toner cartridge set according to an embodiment of the present invention is used in an image forming apparatus that sequentially transfers a plurality of color toner images to an intermediate transfer member. As the image forming apparatus, for example, an image forming apparatus according to another embodiment of the present invention can be used.

  Hereinafter, as a preferred embodiment of the present invention, an example in which a toner cartridge set according to an embodiment of the present invention is used in an image forming apparatus according to another embodiment of the present invention, and an image forming method using the image forming apparatus Will be described. FIG. 1 is a diagram illustrating a configuration of an image forming apparatus 100 that is an example of an embodiment of the present invention. The image forming apparatus 100 is a printer that forms an image on a sheet P as a transfer target. The image forming apparatus 100 includes a feeding unit 10, a transport unit 20, an image forming unit 30, and a discharge unit 80.

  The feeding unit 10 includes a cassette 11 that stores a plurality of sheets P. The sheet P is, for example, a sheet made of paper or a synthetic resin. The feeding unit 10 feeds the sheet P to the conveyance unit 20. The conveyance unit 20 conveys the sheet P to the image forming unit 30. The image forming unit 30 forms an image on the sheet P. The conveyance unit 20 conveys the sheet P on which the image is formed to the discharge unit 80. The discharge unit 80 discharges the sheet P to the outside of the image forming apparatus 100.

  The image forming unit 30 includes an exposure unit 32, a first toner image generation unit 34A, a second toner image generation unit 34B, a third toner image generation unit 34C, a fourth toner image generation unit 34D, a toner cartridge set 36, an intermediate transfer member. An intermediate transfer belt 62, a secondary transfer roller 64, and a fixing unit 70. The toner cartridge set 36 includes a first toner cartridge 36A, a second toner cartridge 36B, a third toner cartridge 36C, and a fourth toner cartridge 36D. Here, the image forming apparatus 100 is a tandem system, and the first toner image generation unit 34A, the second toner image generation unit 34B, the third toner image generation unit 34C, and the fourth toner image generation unit 34D are linearly arranged. ing.

  In the following description of the present specification, in order to avoid redundancy, the first to fourth toner image generation units 34A to 34D may be simply referred to as toner image generation units 34A to 34D. Similarly, the first to fourth toner cartridges 36A to 36D may be simply referred to as toner cartridges 36A to 36D.

  The toner cartridge 36A contains toner for forming a yellow toner image. The toner cartridge 36B contains toner for forming a cyan toner image. The toner cartridge 36C contains toner for forming a magenta toner image. The toner cartridge 36D contains toner for forming a black toner image.

  The exposure unit 32 irradiates each of the toner image generation units 34A to 34D with light based on the image data, and forms an electrostatic latent image on each of the toner image generation units 34A to 34D.

  In the image forming apparatus 100, the toner image generation unit 34A forms a yellow toner image based on the electrostatic latent image, and the toner image generation unit 34B forms a cyan toner image based on the electrostatic latent image. The toner image generation unit 34C forms a magenta toner image based on the electrostatic latent image, and the toner image generation unit 34D forms a black toner image based on the electrostatic latent image.

  The intermediate transfer belt 62 rotates in the direction of arrow R1. Four color toner images are sequentially transferred from the toner image generating units 34A to 34D to the outer surface of the intermediate transfer belt 62 (primary transfer step). The secondary transfer roller 64 transfers the toner image formed on the outer surface of the intermediate transfer belt 62 to the sheet P (secondary transfer process). The fixing unit 70 heats and pressurizes the sheet P to fix the toner image on the sheet P.

  Each of the toner image generation units 34 </ b> A to 34 </ b> D includes a photosensitive drum 40 (image carrier), a charging device 42, a developing device 50, a primary transfer roller 44, a static elimination device 46, and a cleaner 48. In each of the toner image generation units 34 </ b> A to 34 </ b> D, the charging device 42, the developing device 50, the primary transfer roller 44, the charge eliminating device 46, and the cleaner 48 are sequentially arranged along the peripheral surface of the photosensitive drum 40.

  The photosensitive drums 40 of the toner image generation units 34 </ b> A to 34 </ b> D are arranged along the direction of the arrow R <b> 1 that is the rotation direction of the intermediate transfer belt 62 so as to contact the outer surface of the intermediate transfer belt 62. The plurality of primary transfer rollers 44 are provided corresponding to the plurality of photosensitive drums 40 and face the plurality of photosensitive drums 40 via the intermediate transfer belt 62.

  The photosensitive drum 40 rotates in the direction of arrow R2. The charging device 42 charges the peripheral surface of the photosensitive drum 40. Light is irradiated to the peripheral surface of the photoconductive drum 40 by the exposure unit 32 to form an electrostatic latent image.

  The developing device 50 has a two-component developer including, for example, toner and a carrier. The developing devices 50 in the toner image generation units 34A to 34D are connected to the corresponding toner cartridges 36A to 36D, respectively. The structure of the toner cartridges 36A to 36D will be described later.

  The developing device 50 includes a developing roller 52. The developing roller 52 carries a two-component developer including, for example, toner and a carrier. For this reason, the developing roller 52 functions as a developer carrier. The developing roller 52 supplies the toner of the carried developer to the photosensitive drum 40. The developing device 50 attaches toner to the electrostatic latent image on the photosensitive drum 40 to develop the electrostatic latent image and forms a toner image on the peripheral surface of the photosensitive drum 40.

  The primary transfer roller 44 transfers the toner image carried on the photosensitive drum 40 onto the outer surface of the intermediate transfer belt 62. During transfer, a transfer bias is applied to the intermediate transfer belt 62 by the primary transfer roller 44. Thereby, the charge amount of the toner image on the intermediate transfer belt 62 increases. The neutralization device 46 neutralizes the peripheral surface of the photosensitive drum 40 to which the toner image is transferred. The cleaner 48 removes the developer remaining on the peripheral surface of the photosensitive drum 40.

  The toner image transferred to the outer surface of the intermediate transfer belt 62 is transferred to the sheet P via the secondary transfer roller 64. The sheet P on which the toner image has been transferred is conveyed to the fixing unit 70 by the conveyance unit 20. The fixing unit 70 heats and pressurizes the sheet P to fix the toner image (image) to the sheet P. The sheet P on which the image is fixed is discharged from the discharge unit 80 to the outside of the image forming apparatus 100. As described above, the image forming apparatus 100 forms an image on the sheet P.

  Next, toner cartridges included in the toner cartridge set 36 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view of the toner cartridge 36 </ b> A included in the toner cartridge set 36.

  As shown in FIG. 2, the toner cartridge 36 </ b> A includes a toner container 1, toner 6 accommodated in the toner container 1, a transport screw 3 that transports the toner 6, and a stirring paddle 4 that stirs the toner 6.

  The toner container 1 includes a container body 1A having an upper surface opened and a lid 1B that closes the opening of the container body 1A. On the left side of the bottom of the container main body 1A in the drawing, a discharge port 2 that communicates with the developing device 50 of the toner image generation unit 34A is provided. The discharge port 2 is closed by a slide-type shutter (not shown) in a state where the toner cartridge 36A is not attached to the image forming apparatus 100. The shutter is slid to open the discharge port 2 in conjunction with the mounting of the toner cartridge 36A on the image forming apparatus 100.

  A conveying screw 3 is rotatably provided above the discharge port 2 in the container main body 1A. The conveying screw 3 includes a rotating shaft 3A and a spiral fin 3B provided concentrically on the outer periphery of the rotating shaft 3A.

  In the container main body 1A, a stirring paddle 4 is provided above the right side of the conveying screw 3 in the figure. The stirring paddle 4 includes a rotating shaft 4A and a stirring blade 4B attached to the rotating shaft 4A. The stirring blade 4B is attached to the rotating shaft 4A so as to be rotatable in the direction of the arrow R3. The stirring blade 4B is formed using, for example, a resin film such as a polyethylene terephthalate film or a polyester film, and has flexibility.

  A partition wall 5 is provided between the conveying screw 3 and the stirring paddle 4 to divide the inside of the container main body 1A into the conveying screw 3 side and the stirring paddle 4 side along the axial direction of the conveying screw 3. .

  The operation of the toner cartridge 36A will be described with reference to FIG. In the developing device 50 connected to the toner cartridge 36A, when the amount of the toner 6 becomes smaller than a predetermined amount, drive command signals for the conveying screw 3 and the stirring paddle 4 are transmitted from a CPU (not shown) provided in the image forming apparatus 100. Is done. As a result, the stirring paddle 4 rotates in the direction indicated by the arrow R3 in FIG. Then, the toner 6 in the toner container 1 is supplied to the conveying screw 3 side over the partition wall 5 while being stirred.

  Further, the conveying screw 3 is rotated by a drive command signal from the CPU. Thereby, the toner 6 supplied to the conveying screw 3 side is introduced into the developing device 50 from the discharge port 2, and toner is supplied to the developing device 50.

  The toner 6 rubs against the inner wall 1 </ b> C of the toner container 1 by stirring the toner 6 by the stirring paddle 4 and transporting the toner 6 by the transport screw 3. As a result, the charge amount of the toner 6 increases. The toner 6 replenished in the developing device 50 has a larger charge amount due to friction with a carrier (not shown), for example, and is adjusted to a charge amount suitable for development. In this case, the carrier may be stored only in the developing device 50, or may be stored in both the toner container 1 and the developing device 50. In the latter case, the toner cartridge 36 </ b> A may supply both the toner 6 and the carrier to the corresponding developing device 50.

  The structure and operation of the toner cartridge 36A have been described above with reference to FIG. In the present embodiment, since the toner cartridges 36B to 36D are all the same as the toner cartridge 36A except for the toner colorant described later, description of the structure and operation of the toner cartridges 36B to 36D will be omitted.

  Next, the toner container 1 included in the toner cartridges 36A to 36D will be described.

  In this embodiment, when the yellow, cyan, magenta, and black toner images are sequentially primary transferred, the chargeability of the inner wall of the corresponding toner container increases as the order of the primary transfer of the toner images is later. It has become. That is, in the primary transfer step, the toner images formed using the toner of the toner cartridge having a smaller chargeability on the inner wall of the toner container are sequentially transferred. The charging property of the inner wall of the toner container can be adjusted by appropriately selecting the constituent material of the inner wall. As a constituent material of the inner wall, for example, a material containing a charge control agent described later can be cited. The chargeability of the inner wall of the toner container refers to, for example, the chargeability of the inner wall that comes into contact with the toner.

  In the present embodiment, the toner image is formed with the toner of the toner cartridge 36A, the toner image formed with the toner of the toner cartridge 36B, the toner image formed of the toner of the toner cartridge 36C, and the toner of the toner cartridge 36D. The primary transfer is performed in the order of the toner images. Therefore, the chargeability of the inner wall increases in the order of the toner container of the toner cartridge 36A, the toner container of the toner cartridge 36B, the toner container of the toner cartridge 36C, and the toner container of the toner cartridge 36D.

As described above, the amount of charge of the toner in each toner container increases due to friction with the inner wall of the toner container during stirring and conveyance. The charge amount of the toner in each toner container increases according to the chargeability of the inner wall of the toner container. In this embodiment, the chargeability of the inner wall of the corresponding toner container increases as the order of primary transfer is later. Therefore, the charge amount of the toner in the toner container is the toner of the toner cartridge 36A (hereinafter sometimes referred to as toner A), the toner of the toner cartridge 36B (hereinafter sometimes referred to as toner B), The toner becomes larger in the order of the toner in the toner cartridge 36C (hereinafter sometimes referred to as toner C) and the toner in the toner cartridge 36D (hereinafter sometimes referred to as toner D). Accordingly, when the charge amount of toner A, the charge amount of toner B, the charge amount of toner C, and the charge amount of toner D are Q _A , Q _B , Q _C and Q _D in the toner container, respectively, Equation (1) is satisfied.
Q _A <Q _B <Q _C <Q _D (1)

On the other hand, as described above, when performing primary transfer in which a plurality of toner images are superimposed on the intermediate transfer belt 62, the primary transfer roller 44 transfers the toner images to the intermediate transfer belt 62 each time the toner image of each color is transferred. Since the transfer bias is applied, the charge amount of the toner on the intermediate transfer belt 62 increases. For example, a toner image formed using the toner A having the earliest transfer order is applied with a transfer bias by the primary transfer roller 44 a total of four times. Become the largest. On the other hand, since the toner image formed using the toner D having the slowest transfer order is applied only once with the transfer bias by the primary transfer roller 44, the charge amount of the toner in the primary transfer step The amount of increase is the smallest. Accordingly, in the toner image during the primary transfer process from the first color to the fourth color, the increase amount of the charge amount of the toner A, the increase amount of the charge amount of the toner B, the increase amount of the charge amount of the toner C, and the increase amount of the toner D When the increase amount of the charge amount is ΔQ _A , ΔQ _B , ΔQ _C and ΔQ _D , respectively, the following formula (2) is satisfied.
ΔQ _A > ΔQ _B > ΔQ _C > ΔQ _D (2)

  In this embodiment, the charge amount of each toner in the toner container can be adjusted so as to increase as the order of the primary transfer becomes later as shown in Expression (1). Therefore, even if the increase amount of the toner charge amount in the primary transfer process becomes smaller as the order of the primary transfer becomes later as shown in the equation (2), the charge amount in the toner image on the intermediate transfer belt 62 is reduced. Variation can be reduced. Therefore, according to the present exemplary embodiment, it is possible to suppress the secondary transfer failure and the fixing failure due to the variation in the charge amount of the toner without causing the complication of the configuration of the image forming apparatus 100 as much as possible.

  Further, in this embodiment, even if the chargeability of the toner of each color is not adjusted, the variation in the charge amount in the toner image on the intermediate transfer belt 62 can be reduced by adjusting the chargeability of the inner wall of the toner container. . Therefore, for example, when manufacturing each color toner, a common material other than the colorant can be used. This facilitates the production of toner and eliminates the need to change the development conditions for each color in the development process. As a result, the manufacturing cost and running cost of the image forming apparatus 100 can be reduced.

  As a constituent material of the toner container, a material having a polarity opposite to the charged polarity of the toner at the time of development due to friction with the toner is preferable, and for example, a resin can be used. The resin is preferably a thermoplastic resin that can be easily processed, and one or more thermoplastics selected from polyethylene, polystyrene, polypropylene, acrylic resins (polymethacrylate, polymethylmethacrylate, polyethylmethacrylate, etc.), polyester, and vinyl chloride. A resin is more preferable, and polystyrene is still more preferable.

  In addition, as a constituent material of the toner container, a material containing a charge control agent that controls chargeability can be used. By using the charge control agent, the charging property of the inner wall of the toner container can be controlled. Examples of the material containing the charge control agent include a material obtained by adding a charge control agent to a thermoplastic resin.

  The charge control agent can be appropriately selected according to the charge polarity of the toner during development. When the charge polarity of the toner during development is positive, a negative charge control agent that improves negative chargeability is preferable. Further, when the charge polarity of the toner during development is negative, a positive charge control agent that improves positive chargeability is preferable. These negative charge control agents and positive charge control agents can be used in combination.

  Examples of the negative charge control agent include a fluororesin, an acetylacetone metal complex, and a salicylic acid metal salt. Of these, a fluororesin and a salicylic acid-based metal salt that can easily control the chargeability are preferable. Examples of the positive charge control agent include nigrosine compounds and quaternary ammonium salts. In this embodiment, these can be used individually or in combination of 2 or more types.

  When a material obtained by adding a charge control agent to a thermoplastic resin is used as a constituent material of the toner container, the addition amount of the charge control agent is 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Is preferably 1 part by mass or more and 10 parts by mass or less. In particular, when a nigrosine compound is used as the charge control agent, the addition amount of the nigrosine compound is preferably 1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. preferable. When a fluororesin is used as the charge control agent, the addition amount of the fluororesin is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin other than the fluororesin. Part or less is more preferable. In this embodiment, for example, the chargeability of the inner wall of each toner container can be controlled by adjusting the type and amount of charge control agent.

  The method for forming the toner container is not particularly limited. For example, the toner container may be formed by using a mixture of the thermoplastic resin and the charge control agent as a constituent material and adopting a known method as a method for forming the toner container. Can do. Alternatively, the container may be formed using the above-described mixture of the thermoplastic resin and the charge control agent as a constituent material, and then a protective layer that can protect the outer surface of the container is formed, and the toner container may be covered with the protective layer. The protective layer may not contain a charge control agent.

  Next, the developer used in the developing device 50 of the image forming apparatus 100 will be described. As the developer, a two-component developer containing a toner and a carrier is preferable. When the two-component developer is used, at least the toner is supplied to the corresponding developing device 50 from any one of the toner cartridges 36A to 36D described above.

(toner)
The toner may be a positively chargeable toner or a negatively chargeable toner. The toner is a powder containing a plurality of toner particles. The toner particles may include an external additive. When the toner particles include an external additive, the toner particles include a toner base particle and an external additive. The external additive adheres to the surface of the toner base particles. The toner base particles contain a binder resin. The toner base particles may contain an internal additive (for example, at least one of a colorant, a release agent, a charge control agent, and a magnetic powder) in addition to the binder resin, if necessary. If not necessary, the external additive may be omitted. When omitting the external additive, the toner base particles correspond to the toner particles.

  As the binder resin, a thermoplastic resin is preferable. Specific examples of the binder resin include styrene resin, acrylic resin, olefin resin (more specifically, polyethylene resin, polypropylene resin, etc.), vinyl resin (more specifically, vinyl chloride resin, polyvinyl resin). Alcohol resin, vinyl ether resin, N-vinyl resin, etc.), polyester resin, polyamide resin, polyurethane resin, styrene acrylic resin, and styrene butadiene resin. Among them, the styrene acrylic resin and the polyester resin are excellent in the dispersibility of the colorant in the toner, the charging property of the toner, and the fixing property of the toner to the transfer target. One resin may belong to two or more of the above resin types. For example, polystyrene resins belong to both styrene resins and vinyl resins.

  Examples of the colorant include a color colorant and a black colorant. Examples of color colorants include yellow colorants, cyan colorants, and magenta colorants. Examples of the black colorant include carbon black. Further, the black colorant may be a colorant that is toned to black using a yellow colorant, a cyan colorant, and a magenta colorant.

  As the yellow colorant, for example, one or more compounds selected from the group consisting of azo compounds, condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Specific 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 and 194), naphthol yellow S, Hansa yellow G, and C.I. I. Bat yellow is mentioned.

  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. Specific examples of the cyan colorant include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, and 66), phthalocyanine blue, C.I. I. Bat Blue and C.I. I. Acid blue.

  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. Specific 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 and 254).

  Examples of the release agent include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; polyethylene oxide wax, polyethylene oxide wax Oxides of aliphatic hydrocarbon waxes such as block copolymers of the following: plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, and rice wax; animal waxes such as beeswax, lanolin, and whale wax; Mineral waxes such as ozokerite, ceresin and petrolatum; waxes mainly composed of fatty acid esters such as montanic acid ester wax and castor wax; waxes in which a part or all of the fatty acid ester is deoxidized For example, it deoxidized carnauba wax) can be preferably used. In the present embodiment, one type of release agent may be used alone, or a plurality of types of release agents may be used in combination.

  As the charge control agent, a positive charge control agent is preferably used when developing with a positively charged toner, and a negative charge control agent is used when developing with a negatively charged toner. It is preferable.

  As the positive charge control agent, pyridazine, pyrimidine, pyrazine, 1,2-oxazine, 1,3-oxazine, 1,4-oxazine, 1,2-thiazine, 1,3-thiazine, 1,4-thiazine, 1 , 2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6-oxadiazine, 1,3 , 4-thiadiazine, 1,3,5-thiadiazine, 1,2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1,2,4,6 -Azine compounds such as oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline, quinoxaline; azine fast red FC, azine fast red 12BK, azine violet BO, a Direct dyes composed of azine compounds such as N-brown 3G, azine light brown GR, azine dark green BH / C, azine deep black EW, azine deep black 3RL; nigrosine compounds such as nigrosine, nigrosine salts, nigrosine derivatives; nigrosine BK Acid dyes composed of nigrosine compounds such as nigrosine NB and nigrosine Z; metal salts of naphthenic acid or higher fatty acids; alkoxylated amines; alkylamides; quaternary ammonium salts such as benzyldecylhexylmethylammonium chloride and decyltrimethylammonium chloride preferable. Examples of the negative charge control agent include acetylacetone metal complexes and salicylic acid metal salts. In the present embodiment, one type of charge control agent may be used alone, or a plurality of types of charge control agents may be used in combination.

  Examples of the magnetic powder include at least one of iron (more specifically, ferrite, magnetite, etc.), ferromagnetic metal (more specifically, cobalt, nickel, etc.), iron, and a ferromagnetic metal other than iron. , Ferromagnetic alloys that have been subjected to ferromagnetization (for example, heat treatment), and chromium dioxide. In the present embodiment, one type of magnetic powder may be used alone, or a plurality of types of magnetic powder may be used in combination.

  The external additive is used, for example, to improve the fluidity or handleability of the toner. In order to improve the fluidity or handleability of the toner, the amount of the external additive used is preferably 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. More preferably, they are 5 to 5 mass parts. In order to improve the fluidity or handleability of the toner, the particle diameter of the external additive is preferably 0.01 μm or more and 1.0 μm or less.

  As the external additive, inorganic particles are preferable, and particles of silica particles and metal oxides (more specifically, particles of alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) are more preferable. . The surface of the inorganic particles may be hydrophobized using a hydrophobizing agent. Examples of the hydrophobizing agent include silane compounds (more specifically, aminosilane and the like), silazane compounds (more specifically, HMDS (hexamethyldisilazane) and the like), silicone oil, titanate coupling agents, and silane. A coupling agent can be preferably used. In the present embodiment, one type of external additive may be used alone, or a plurality of types of external additives may be used in combination.

  The toner particles may be toner particles without a shell layer (hereinafter referred to as non-capsule toner particles) or toner particles with a shell layer (hereinafter referred to as capsule toner particles). Also good. In the capsule toner particles, the toner base particles include a toner core and a shell layer formed on the surface of the toner core. The shell layer is substantially composed of a resin. For example, by covering a toner 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 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 toner core or may partially cover the surface of the toner core. The shell layer may be substantially composed of a thermosetting resin, may be substantially composed of a thermoplastic resin, or may contain both a thermoplastic resin and a thermosetting resin. .

  Non-capsule toner particles can be produced, for example, by a pulverization method or an aggregation method. In these methods, the internal additive is easily dispersed well in the binder resin of the non-capsule toner particles. In general, toner is roughly classified into pulverized toner and polymerized toner (also referred to as chemical toner). The toner obtained by the pulverization method belongs to the pulverized toner, and the toner obtained by the aggregation method belongs to the polymerized toner.

  In an example of the pulverization method, first, a binder resin, a colorant, a charge control agent, and a release agent are mixed. Subsequently, the obtained mixture is melt-kneaded using a melt-kneading apparatus (for example, a single-screw or twin-screw extruder). Subsequently, the obtained melt-kneaded product is pulverized, and the obtained pulverized product is classified. Thereby, toner mother particles are obtained. When the pulverization method is used, there is a tendency that toner mother particles can be produced more easily than when the aggregation method is used.

  In an example of the aggregation method, first, these fine particles are aggregated in an aqueous medium containing fine particles of a binder resin, a release agent, a charge control agent, and a colorant until a desired particle size is obtained. Thereby, aggregated particles containing a binder resin, a release agent, a charge control agent, and a colorant are formed. Subsequently, the obtained aggregated particles are heated to unite the components contained in the aggregated particles. Thereby, toner mother particles having a desired particle diameter are obtained.

  When producing the capsule toner particles, the method for forming the shell layer is arbitrary. 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.

(Career)
As the carrier, a magnetic carrier is preferable, and a magnetic carrier in which a carrier core is coated with a coat layer is more preferable.

  As the material for the carrier core, metals such as ferrite (more specifically, ferromagnetic ferrite), magnetite, iron, nickel, cobalt, and the like can be suitably used. Alloys or mixtures of these metals with metals selected from copper, zinc, antimony, aluminum, lead, tin, bismuth, beryllium, manganese, magnesium, selenium, tungsten, zirconium, and vanadium are also included in the carrier core. It can be suitably used as a material. In addition, the metal includes a metal oxide (more specifically, iron oxide, titanium oxide, magnesium oxide, etc.), a nitride (more specifically, chromium nitride, vanadium nitride, etc.), or a carbide (more specifically, May be mixed with silicon carbide, tungsten carbide, etc.) and the resulting mixture may be used as a material for the carrier core. Among these materials, ferrite and magnetite are particularly preferable. In the present embodiment, one of these materials may be used alone, or two or more materials may be used in combination.

In order to improve the developability of the two-component developer, the volume median diameter (D ₅₀ ) of the carrier core is preferably 30 μm or more and 100 μm or less.

  Examples of the material for the coat layer covering the carrier core include olefin resins (more specifically, polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc.), acrylic resins (more specifically, polymethyl methacrylate). ), Styrene resin, acrylonitrile resin, amino resin (more specifically, urea-formaldehyde resin, etc.), polyamide resin, urethane resin, polycarbonate resin, silicone resin having organopolysiloxane, modified silicone resin (more specifically, Specifically, alkyd resin, polyester resin, epoxy resin or modified silicone resin by polyurethane, etc.), fluororesin (more specifically, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoro) Ethylene), vinyl resins (more specifically, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, etc.), polyester resins, And an epoxy resin can be preferably used. Note that one material may belong to two or more of the above material types. For example, polyvinylidene fluoride belongs to both fluororesins and vinyl resins. The mass ratio of the carrier core and the coat layer is preferably 2 parts by mass or more and 30 parts by mass or less of the coat layer with respect to 100 parts by mass of the carrier core.

(Method for producing two-component developer)
A two-component developer can be produced by stirring the mixture obtained by mixing the above-described toner and carrier. The amount of toner contained in the two-component developer is preferably 1 part by mass or more and 20 parts by mass or less, and more preferably 3 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the carrier. For the stirring of the mixture, for example, a ball mill, a Nauter mixer (registered trademark) manufactured by Hosokawa Micron Corporation, or a rocking mixer (registered trademark) manufactured by Aichi Electric Co., Ltd. can be used.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the toner cartridge including the conveying screw and the stirring paddle has been described as an example. However, in the present invention, the conveying screw and the stirring paddle are not provided as long as the toner in the toner container can be conveyed to the developing device. May be. In the above embodiment, a toner cartridge set having four toner cartridges has been described as an example. However, in the present invention, the number of toner cartridges is not particularly limited as long as it is two or more.

  Examples of the present invention will be described.

<Measurement method of physical properties>
First, a method for measuring physical properties will be described.

[Measurement of softening point]
The softening point of the binder resin was measured using a Koka flow tester (“CFT-500D” manufactured by Shimadzu Corporation). Specifically, the binder resin (sample) was set in a Koka flow tester. A sample of 1 cm ³ was melted and flowed out under conditions of a die pore diameter of 1 mm, a plunger load of 20 kg / cm ² , and a heating rate of 6 ° C./min. Thereby, an S-shaped curve related to temperature (° C.) / Stroke (mm) was obtained. The softening point of the sample was read from the obtained S-shaped curve. Specifically, with respect to the resulting S-shaped curve, the maximum value of the stroke and S _1, the stroke value of the low-temperature side of the base line was S _2. The temperature at which the stroke value was (S ₁ + S ₂ ) / 2 was taken as the softening point of the sample.

[Measurement of triboelectric charge between toner container material and toner]
Materials used for manufacturing a toner container described later were prepared and mixed with an FM mixer (manufactured by Nippon Coke Industries Co., Ltd.) to obtain a mixture. Next, the mixture was melt-kneaded with an extruder, extruded into a strand shape, formed into a plate shape with a thickness of 2 mm with a drum roll, cooled, and then cut into a square with a side of 20 mm to produce two pellets. did. Between two pellets, 0.01 g of toner used in Developer D, which will be described later, is put on top of each other, 1 kg of weight is placed on the upper pellet, and then the lower pellet using a rotating disk jig. Was rotated at a rotation speed of 100 rpm for 1 minute. After completion of the rotation, the charge amount of the toner charged by friction with the pellets (friction charge amount) was measured using a Q / m meter (“MODEL 210HS” manufactured by Trek). The larger the triboelectric charge amount of the toner, the higher the chargeability of the constituent material of the toner container. Therefore, the triboelectric charge obtained in this measurement is an index of the charging property of the inner wall of the toner container.

<Method for producing developer>
Developers A to D (each two-component developer for developing an electrostatic latent image) were manufactured as developers for evaluation. A method for producing the developers A to D will be described in detail below.

[Production Method for Developer A]
(Preparation of toner base particles)
First, the binder resin was manufactured by the method shown below. 1.0 mol of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 4.5 mol of terephthalic acid, 0.5 mol of trimellitic anhydride, 4 g of dibutyltin oxide, Was placed in a reaction vessel. The contents of the reaction vessel were reacted at 230 ° C. for 8 hours under a nitrogen atmosphere. Subsequently, the unreacted raw material was removed by distilling off the content of the reaction vessel under reduced pressure under the condition of 8.3 kPa. The obtained reaction product was washed and dried. This obtained the polyester resin whose softening point is 120 degreeC.

100 parts by mass of the obtained polyester resin, 4 parts by mass of an azo pigment (“CI Pigment Yellow 180” manufactured by Sanyo Dyeing Co., Ltd.) as a colorant, and carnauba wax (“Carnauba manufactured by Kato Yoko Co., Ltd.) as a release agent. No. 1 ”) 10 parts by mass and 3 parts by mass of a quaternary ammonium salt (“ FCA201PS ”manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent, using an FM mixer (“ FM20B ”manufactured by Nippon Coke Industries, Ltd.) Mixed. The obtained mixture was melt-kneaded at 150 ° C. using a twin screw extruder (“TEM45” manufactured by Toshiba Machine Co., Ltd.). The resulting kneaded product was cooled. The cooled kneaded material was coarsely pulverized using an impact type screen type pulverizer (“Fezamill (registered trademark) (FM-2S) 350 × 600 type” manufactured by Hosokawa Micron Corporation). The obtained coarsely pulverized product was finely pulverized using a supersonic jet pulverizer (“Jet Mill IDS-2” manufactured by Nippon Pneumatic Industry 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 base particles used for developer A were obtained. The volume median diameter (D ₅₀ ) of the toner base particles was 7 μm.

(Preparation of hydrophobic silica particles)
As an external additive, hydrophobic silica particles were prepared by the following method. Silica particles (“RA-200H” manufactured by Nippon Aerosil Co., Ltd.) were pulverized using a supersonic jet pulverizer (“Jet Mill IDS-2” manufactured by Nippon Pneumatic Industry Co., Ltd.). 100 parts by mass of the crushed silica particles are put into a closed FM mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), and the hydrophobizing agent (3-aminopropyltriethoxysilane, dimethyl silicone oil and In a mass ratio of 1: 1) was uniformly dispersed. Subsequently, the surface of the silica particles was hydrophobized by reacting at 110 ° C. for 2 hours while mixing the silica particles and the hydrophobizing agent using a closed FM mixer. Subsequently, the side reaction product was removed by a reduced pressure treatment, and then a heat treatment at 200 ° C. was further performed for 1 hour to obtain hydrophobic silica particles.

(Preparation of conductive titanium oxide particles)
As another external additive, conductive titanium oxide particles were produced by the following method. A mixture of titanium tetrachloride and oxygen gas produced by the chlorine method was introduced into the gas phase oxidation reactor. Subsequently, titanium oxide (bulk) was obtained by performing a gas phase oxidation reaction of the mixture at a temperature of 1000 ° C. in the reactor. The obtained titanium oxide (bulk) was pulverized with a hammer mill. Subsequently, the obtained pulverized titanium oxide was washed and then dried at a temperature of 110 ° C. Further, the dried pulverized titanium oxide was crushed by a jet mill. As a result, fine titanium oxide particles were obtained.

Subsequently, using an FM mixer (manufactured by Nippon Coke Kogyo Co., Ltd.), 100 parts by mass of the obtained titanium oxide fine particles and 2.6 parts by mass of isopropyl triisostearoyl titanate were mixed at a stirring speed of 40 m / sec. The titanium oxide fine particles were surface-treated by a coupling reaction at 130 ° C. Subsequently, the surface-treated titanium oxide fine particles were dried and crushed. As a result, fine titanium oxide particles having an electric resistivity of 1.0 × 10 ⁹ Ω · cm and a methanol hydrophobization degree of 35% were obtained. Since the electrical resistivity of the titanium oxide fine particles is likely to vary depending on the manufacturing conditions, the surface treatment was repeated until titanium oxide fine particles having a desired electrical resistivity were obtained.

Subsequently, the surface-treated titanium oxide fine particles were subjected to tin antimony treatment. Specifically, the surface-treated titanium oxide fine particles were dispersed in water to prepare a 100 g / L suspension of titanium oxide fine particles. Subsequently, the obtained titanium oxide suspension was heated to 70 ° C. Further, a solution obtained by dissolving 2 g of tin chloride (SnCl ₄ .5H ₂ O) and 0.1 g of antimony chloride (SbCl ₂ ) in 50 mL of a 2N hydrochloric acid aqueous solution and a 10% by mass sodium hydroxide aqueous solution were oxidized. It was added over 1 hour to the titanium oxide suspension so that the pH of the titanium suspension was maintained at 2-3. As a result, a conductive layer composed of each hydrate of tin oxide and antimony oxide was formed on the surface of the titanium oxide fine particles in the titanium oxide suspension. Thereafter, the titanium oxide suspension was filtered (solid-liquid separation), and the resulting titanium oxide fine particles were washed. Subsequently, the washed titanium oxide fine particles were fired at a temperature of 600 ° C. Subsequently, the fired titanium oxide fine particles were crushed using a jet mill (manufactured by Nippon Pneumatic Industry Co., Ltd.). As a result, electrically conductive titanium oxide particles having an electrical resistivity of 50 Ω · cm and hydrophilic properties were obtained.

(Production of toner by external treatment)
Using an FM mixer (“FM-10B” manufactured by Nippon Coke Kogyo Co., Ltd.), 100 parts by mass of toner base particles (toner base particles prepared by the above procedure) and hydrophobic silica particles (hydrophobic prepared by the above procedure) By mixing 1.5 parts by mass of conductive silica particles) and 1.0 part by mass of conductive titanium oxide particles (conductive titanium oxide particles prepared by the above-described procedure) at a rotational speed of 3500 rpm for 5 minutes, a toner base is obtained. External additives (hydrophobic silica particles and conductive titanium oxide particles) were adhered to the surface of the particles. Thereafter, the obtained toner was sieved using a sieve of 200 mesh (aperture 75 μm). As a result, a toner containing many toner particles (non-capsule toner particles) was obtained.

(Creation of carrier)
2 kg of an epoxy resin (“jER (registered trademark) 1004” manufactured by Mitsubishi Chemical Corporation) was dissolved in 20 L of acetone. To the obtained solution, 100 g of diethylenetriamine and 150 g of phthalic anhydride were added and mixed. The obtained mixed liquid was sprayed onto 10 kg of the carrier core while feeding hot air at 80 ° C. using a fluidized bed coating apparatus (“Spiraflow (registered trademark) SFC-5” manufactured by Freund Sangyo Co., Ltd.). As the carrier core, a Mn—Mg—Sr ferrite core (“EF-35” manufactured by Powder Tech Co., Ltd., particle diameter: 35 μm) was used. As a result, the carrier core was coated with an uncured organic layer (fluidized bed). The carrier core coated with the uncured organic layer (fluidized bed) was heated at 180 ° C. for 1 hour using a dryer. Thereby, the fluidized bed was hardened. As a result, a carrier having a carrier core and a resin layer (coat layer) covering the carrier core was obtained.

(Mixing of toner and carrier)
10 parts by mass of the toner prepared as described above and 100 parts by mass of the carrier prepared as described above were mixed, and the resulting mixture was stirred for 30 minutes by a ball mill. As a result, yellow developer A (two-component developer) was obtained.

[Production Method for Developer B]
Instead of 4 parts by mass of an azo pigment (Sanyo Dye Co., Ltd. “CI Pigment Yellow 180”), 3 parts by mass of a phthalocyanine pigment (Sanyo Dye Co., Ltd. “CI Pigment Blue 15: 1”) is used. Except for the above, a cyan developer B (two-component developer) was obtained in the same manner as in the method for producing developer A described above.

[Production Method for Developer C]
Instead of 4 parts by mass of the azo pigment (Sanyo Dye Co., Ltd. “CI Pigment Yellow 180”), 3 parts by mass of the quinacridone pigment (Sanyo Dye Co., Ltd. “CI Pigment Red 122”) was used. Except for the above, a magenta developer C (two-component developer) was obtained in the same manner as in the method for producing developer A described above.

[Method for Producing Developer D]
Instead of 4 parts by mass of an azo pigment (“CI Pigment Yellow 180” manufactured by Sanyo Dye Co., Ltd.), 4 parts by mass of carbon black (“REGAL (registered trademark) 330R” manufactured by Cabot Specialty Chemicals) was used. Except for this, a black developer D (two-component developer) was obtained in the same manner as in the method for producing developer A described above.

<Manufacturing method of toner container>
Toner containers A to K were manufactured as toner containers for evaluation. A method for manufacturing toner containers A to K will be described below.

[Method for Manufacturing Toner Container A]
FM mixer (Japan) 100 parts by weight of impact-resistant polystyrene (“H700” manufactured by Toyo Styrene Co., Ltd.) and 5 parts by weight of salicylic acid metal salt (“BONTRON (registered trademark) X-11” manufactured by Orient Chemical Co., Ltd.) Coke Kogyo Co., Ltd.) to obtain a mixture. Next, the mixture was melt-kneaded with an extruder, extruded into a strand, and then cut to produce pellets. Using the pellets, a toner container A for a color composite machine (“TASKalfa 5551ci” manufactured by Kyocera Document Solutions Co., Ltd.) was manufactured using a molding machine.

[Method for Manufacturing Toner Container B]
Toner container B was produced in the same manner as toner container A, except that the amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) was 10 parts by mass.

[Method for Manufacturing Toner Container C]
Toner container C was produced in the same manner as toner container A except that the amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) was changed to 15 parts by mass.

[Method for Manufacturing Toner Container D]
Toner container D was produced in the same manner as toner container A, except that the amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) was 20 parts by mass.

[Method for Manufacturing Toner Container E]
Instead of 5 parts by mass of salicylic acid-based metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.), fluororesin ("Neofluon (registered trademark) PFA AP-210" manufactured by Daikin Industries, Ltd.) 5 A toner container E was produced in the same manner as the toner container A except that the parts by mass were used.

[Method for Manufacturing Toner Container F]
Instead of 5 parts by mass of salicylic acid-based metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.), fluororesin ("Neofluon (registered trademark) PFA AP-210" manufactured by Daikin Industries, Ltd.) 10 A toner container F was produced in the same manner as the toner container A except that the parts by mass were used.

[Method for Manufacturing Toner Container G]
Instead of 5 parts by mass of a salicylic acid-based metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.), a fluororesin ("Neofluon (registered trademark) PFA AP-210" manufactured by Daikin Industries, Ltd.) 15 A toner container G was produced in the same manner as the toner container A except that the parts by mass were used.

[Method for Manufacturing Toner Container H]
Instead of 5 parts by mass of a salicylic acid-based metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.), a fluororesin ("Neofluon (registered trademark) PFA AP-210" manufactured by Daikin Industries, Ltd.) 20 A toner container H was produced in the same manner as the toner container A except that the parts by mass were used.

[Method for Manufacturing Toner Container I]
The amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) used was 20 parts by mass, and carbon black ("Ketjen Black (Lion Specialty Chemicals Co., Ltd.)" (Registered trademark) EC300J ") Toner container I was produced in the same manner as toner container A except that 10 parts by mass were further mixed.

[Production Method of Toner Container J]
The amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) used was 20 parts by mass, and carbon black ("Ketjen Black (Lion Specialty Chemicals Co., Ltd.)" (Registered trademark) EC300J ") A toner container J was produced in the same manner as in the toner container A except that 7 parts by mass were further mixed.

[Method for Manufacturing Toner Container K]
The amount of salicylic acid metal salt ("BONTRON (registered trademark) X-11" manufactured by Orient Chemical Co., Ltd.) used was 20 parts by mass, and carbon black ("Ketjen Black (Lion Specialty Chemicals Co., Ltd.)" (Registered trademark) EC300J ") A toner container K was produced in the same manner as in the toner container A except that 3 parts by mass were further mixed.

<Preparation of toner cartridge set>
[Example 1]
In the toner cartridge set of Example 1, the toner container A, the toner container B, the toner container C, and the toner container D are respectively filled with toner (yellow) of developer A, toner (cyan) of developer B, and developer C. A toner cartridge set having four toner cartridges was prepared by filling toner (magenta) and developer D toner (black).

[Example 2, Example 3, and Comparative Examples 1-3]
The toner cartridge sets of Example 2 and Example 3 were prepared in the same manner as in Example 1 except that the toner container and the toner to be filled were changed as shown in Table 1. Also, toner cartridge sets of Comparative Examples 1 to 3 were prepared in the same manner as in Example 1 except that the toner container and the toner to be filled were changed as shown in Table 2. In Tables 1 and 2, “transfer order” in the column “toner” means the transfer order of toner images formed using the toner shown in “kind” in the column “toner”.

<Evaluation method>
The evaluation methods of the toner cartridge sets of Examples 1 to 3 and Comparative Examples 1 to 3 are as follows.

[Transfer scattering and electrostatic offset]
Images were formed using a developer to evaluate transfer scattering and electrostatic offset. As an evaluation machine, a color multifunction machine (“TASKalfa 5551ci” manufactured by Kyocera Document Solutions Inc.) was used. The developer described above was charged into the developing device of the evaluation machine, and the toner cartridge set described above was mounted on the evaluation machine. Specifically, the evaluator had four developing devices (first to fourth developing devices). The order of arrangement of the first to fourth developing devices is from the first developing device located in the uppermost stream of primary transfer (the position where primary transfer is earliest) to the downstream of primary transfer (primary transfer). The second developing device, the third developing device, and the fourth developing device were arranged in this order toward the later timing side. First developer is charged with developer A, second developer is charged with developer B, third developer is charged with developer C, and fourth developer is charged with developer D. did. When each toner cartridge set was mounted, a toner cartridge filled with toner (yellow) of developer A was mounted as a toner cut ridge corresponding to the first developing device. As a toner cut ridge corresponding to the second developing device, a toner cartridge filled with toner (cyan) of developer B was attached. As a toner cut ridge corresponding to the third developing device, a toner cartridge filled with developer C toner (magenta) was attached. As a toner cut ridge corresponding to the fourth developing device, a toner cartridge filled with toner of developer D (black) was attached.

Using the evaluation machine, an image including a solid portion with a printing rate of 5% was printed on 5000 sheets of evaluation paper in an environment of a temperature of 20 ° C. and a humidity of 50% RH. Thereafter, transfer scattering and electrostatic offset were evaluated. Note that Mondi paper ("ColorCopy (registered trademark)", A4 size, 90 g / m ² ) was used as the evaluation paper. Hereinafter, a method for evaluating transfer scattering and electrostatic offset will be described.

(Evaluation method of transfer scattering)
Using the evaluation machine, an evaluation image including a solid portion and a character portion having a printing rate of 100% was continuously printed on the evaluation paper in an environment of a temperature of 20 ° C. and a humidity of 50% RH. The transfer scattering of each evaluation image (mainly the character portion) was evaluated. The results are shown in Tables 1 and 2. The evaluation criteria are as follows.
○ (good): no transfer scattering was observed, and the image quality was good.
× (Poor): Scattering of transfer was recognized and the image quality was poor.

(Evaluation method of electrostatic offset)
Using the evaluation machine, an evaluation image including a solid portion and a character portion having a printing rate of 100% was continuously printed on the evaluation paper in an environment of a temperature of 20 ° C. and a humidity of 50% RH. The electrostatic offset of the solid part of each evaluation image was evaluated by the period of the fixing roller of the fixing unit. The results are shown in Tables 1 and 2. The evaluation criteria are as follows.
O (good): No electrostatic offset was observed, and the image quality was good.
X (Poor): Electrostatic offset was recognized and the image quality was poor.

[Evaluation of toner charge after evaluation]
After the evaluation of the transfer scattering and electrostatic offset described above, the charge amount of the toner remaining in the toner container of each toner cartridge was measured by a Q / m meter (“MODEL 210HS” manufactured by Trek). The results are shown in Tables 1 and 2.

  As shown in Table 1, in Examples 1 to 3, the later the toner image transfer order, the greater the triboelectric charge amount between the toner container material and the toner (hereinafter sometimes referred to as triboelectric charge amount). It was. Therefore, in Examples 1 to 3, it can be evaluated that the chargeability of the inner wall of the corresponding toner container is increased as the order of transfer of the toner images is later. In Examples 1 to 3, the toner charge amount after evaluation increased as the order of toner image transfer was later. In Examples 1 to 3, good evaluation results were obtained in any evaluation of transfer scattering and electrostatic offset.

  As shown in Table 2, in Comparative Example 1, the triboelectric charge amount was smaller as the order of toner image transfer was later. Comparative Example 2 showed the same value for the triboelectric charge amount when the transfer order of the toner images was the third and fourth. Comparative Example 3 showed the same value for the triboelectric charge amount regardless of the order of transfer of the toner images. Therefore, in Comparative Examples 1 to 3, the tendency that the charging property of the inner wall of the corresponding toner container increases as the order of transfer of the toner images becomes later was not recognized. In Comparative Examples 1 to 3, the relationship between the order of toner image transfer and the amount of toner charge after evaluation showed the same tendency as the relationship between the order of toner image transfer and the amount of triboelectric charge described above. In Comparative Example 3, the evaluation of transfer scattering was x (bad). In Comparative Examples 1 to 3, the evaluation of the electrostatic offset was x (bad).

  As is clear from Tables 1 and 2, Examples 1 to 3 were able to suppress transfer scattering compared to Comparative Example 3. Moreover, Examples 1-3 have suppressed the electrostatic offset compared with Comparative Examples 1-3.

  The toner cartridge set, the image forming apparatus, and the image forming method according to the present invention can be used to form an image in, for example, a copying machine or a printer.

DESCRIPTION OF SYMBOLS 1 Toner container 1C Inner wall 6 Toner 36 Toner cartridge set 36A-36D Toner cartridge 40 Photosensitive drum 42 Charging device 44 Primary transfer roller 46 Static elimination device 48 Cleaner 50 Developing device 52 Developing roller 62 Intermediate transfer belt 64 Secondary transfer roller 100 Image Forming device P sheet

Claims (4)

A toner cartridge set that is used in an image forming apparatus that sequentially transfers toner images of a plurality of colors to an intermediate transfer member, and has a plurality of toner cartridges for each color,
Each of the toner cartridges includes a toner container and a toner contained in the toner container and forming the toner image,
The toner cartridge set in which the chargeability of the inner wall of the corresponding toner container is increased as the order of transfer of the toner images is later.   The toner cartridge set according to claim 1, wherein an inner wall of each of the toner containers includes a charge control agent that controls chargeability. The charge control agent is a salicylic acid metal salt,
At least one of the plurality of toner containers includes carbon black on an inner wall;
3. The toner cartridge set according to claim 2, wherein the amount of the carbon black with respect to the salicylic acid-based metal salt on the inner wall of the corresponding toner container decreases as the order of transfer of the toner images becomes later. An image forming apparatus for sequentially transferring toner images of a plurality of colors to an intermediate transfer member,
Have multiple toner cartridges for each color,
Each of the toner cartridges includes a toner container and a toner contained in the toner container and forming the toner image,
The image forming apparatus, wherein the chargeability of the inner wall of the corresponding toner container is increased as the order of transfer of the toner images is later.

Images