JP2015022078A - Image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that suppresses occurrence of a change in density of images due to passing of silica particles through a cleaning blade under a low-temperature and low-humidity environment, and an increase in a rotational load of an image carrier under a high-temperature and high-humidity environment.SOLUTION: An image forming apparatus includes: an image carrier; developing means for accommodating an electrostatic charge image developer including a toner containing an external additive containing first silica particles having a number average particle diameter of 100 nm or more and 180 nm or less and a shape factor SF2 of 130 or more and 180 or less and second silica particles having a number average particle diameter of 100 nm or more and 180 nm or less and a shape factor SF2 of 100 or more and 125 or less, and developing electrostatic charge images formed on the surface of the image carrier as toner images with the electrostatic charge image developer; cleaning means including a cleaning blade cleaning the surface of the image carrier; and lubricant supply means for supplying a lubricant to the surface of the image carrier.

Description

  The present invention relates to an image forming apparatus and a process cartridge.

  A method for visualizing image information through an electrostatic charge image by electrophotography or the like is currently used in various fields. In electrophotography, image information is formed as an electrostatic charge image on the surface of an image carrier (photoreceptor) by charging and exposure processes, and a toner image is developed on the surface of the photoreceptor using a developer containing toner. The toner image is visualized as an image through a transfer process for transferring the toner image to a recording medium such as paper and a fixing process for fixing the toner image on the surface of the recording medium.

  For example, Patent Document 1 states that “an external additive in which a plurality of silica fine particles are non-spherical amorphous silica particles fixed in a chain, and the major axis (D50) of the non-spherical amorphous silica particles is 8 nm or more and 50 nm or less. Toner containing "is disclosed.

  Patent Document 2 discloses “a toner including an external additive having a plurality of primary particles irreversibly coalesced and having a shape factor SF2 of 110 to 160”.

JP 2010-243664 A JP 2010-224502 A

  An object of the present invention is a phenomenon in which the density change of an image caused by slipping of silica particles from a cleaning blade in a low temperature and low humidity environment (hereinafter referred to as “ghost”), and an image carrier in a high temperature and high humidity environment Is to provide an image forming apparatus that suppresses an increase in rotational load (hereinafter referred to as “rotational torque”).

The above problem is solved by the following means.
The invention according to claim 1
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Toner particles, first silica particles having a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 130 to 180, and a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 100 or more And an electrostatic charge image developer formed on the surface of the image carrier by the electrostatic charge image developer. Developing means for developing the toner image as a toner image;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Lubricant supply means for supplying a lubricant to the surface of the image carrier;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising:

The invention according to claim 2
The external addition amount of the first silica particles, the external addition amount of the second silica particles, and the supply amount of the lubricant per 1000 rotations of the image carrier satisfy the following formulas (1) and (2). The image forming apparatus according to claim 1.
Formula (1): (Y / X) × Z = a
Formula (2): 0.006 ≦ a ≦ 0.065
(In Formula (1) and Formula (2), X is the external addition amount (mass%) of the first silica particles to the toner particles, and Y is the external addition amount of the second silica particles to the toner particles. Z is the amount of lubricant supplied (mg / cm ² ) supplied per 1000 rotations of the image carrier.

The invention according to claim 3
The mass ratio of the external addition amount of the first silica particles and the external addition amount of the second silica particles to the toner particles (external addition amount of the first silica particles / external addition amount of the second silica particles) is: The image forming apparatus according to claim 1, wherein the image forming apparatus is 0.1 or more and 2.9 or less.

The invention according to claim 4
The image forming apparatus according to claim 1, wherein the lubricant is zinc stearate.

The invention according to claim 5
An image carrier,
Toner particles, first silica particles having a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 130 to 180, and a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 100 or more And an electrostatic charge image developer formed on the surface of the image carrier by the electrostatic charge image developer. Developing means for developing the toner image as a toner image;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Lubricant supply means for supplying a lubricant to the surface of the image carrier;
And a process cartridge that is detachably attached to the image forming apparatus.

  According to the first aspect of the present invention, in an image forming apparatus including a cleaning unit having a cleaning blade and a lubricant supply unit, the first silica particles and the second silica particles are not used in combination as external toner additives. There is provided an image forming apparatus that suppresses a ghost in a low temperature and low humidity environment and an increase in rotational torque of an image carrier in a high temperature and high humidity environment.

  According to the second aspect of the present invention, in the image forming apparatus including the cleaning unit having the cleaning blade and the lubricant supply unit, the external addition amount of the first silica particles, the external addition amount of the second silica particles, and the supply of the lubricant As compared with the case where the amount does not satisfy the above formula (1), there is provided an image forming apparatus that suppresses a ghost in a low temperature and low humidity environment and an increase in rotational torque of the image carrier in a high temperature and high humidity environment.

  According to the invention of claim 3, compared with the case where the mass ratio of the external addition amount of the first silica particles and the external addition amount of the second silica particles does not satisfy the above range, the ghost in the low temperature and low humidity environment, and the high temperature An image forming apparatus that suppresses an increase in rotational torque of an image carrier under a high humidity environment is provided.

  According to the fourth aspect of the present invention, in an image forming apparatus including a cleaning unit having a cleaning blade and a lubricant supply unit, the first silica particles and the second silica particles are not used in combination as external toner additives. Further, there is provided an image forming apparatus in which zinc stearate is applied as a lubricant to suppress a ghost in a low temperature and low humidity environment and an increase in rotational torque of an image carrier in a high temperature and high humidity environment.

  According to the invention according to claim 5, in the process cartridge including the cleaning unit having the cleaning blade and the lubricant supply unit, as compared with the case where the first silica particles and the second silica particles are not used together as the external additive of the toner, A process cartridge is provided that suppresses a ghost under a low temperature and low humidity environment and an increase in rotational torque of an image carrier under a high temperature and high humidity environment.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium Transferred onto the surface of the image carrier, cleaning means having a cleaning blade for cleaning the surface of the image carrier, lubricant supply unit for supplying a lubricant to the surface of the image carrier, and transferred onto the surface of the recording medium. Fixing means for fixing the toner image.
The electrostatic charge image developer includes toner particles, first silica particles having a number average particle diameter of 100 nm to 180 nm and a shape factor SF2 of 130 to 180 (hereinafter referred to as “deformed silica particles”), And an external additive containing second silica particles (hereinafter referred to as “spherical silica particles”) having a number average particle diameter of 100 nm to 180 nm and a shape factor SF2 of 100 to 125.

  Here, if the toner includes large-diameter irregular-shaped silica particles having a particle size and a shape factor in the above ranges as external additives, the irregular-shaped silica particles are embedded in the toner particle surface and the toner particle surface is recessed. Since it is difficult for the deformed silica particles to migrate to the toner, the transfer maintenance property and heat storage property of the toner are improved.

  Further, in the image forming apparatus provided with the lubricant supply means for supplying the lubricant to the surface of the image carrier when the irregular shaped silica particles are externally added to the toner particles, the irregular shaped silica particles released from the toner particles are used as an abrasive. The lubricant film is appropriately shaved on the surface of the image carrier to suppress the formation of an excessive lubricant film. This phenomenon of excessive formation of a lubricant film may be referred to as “lubricant filming”.

  However, the deformed silica particles are hardly released from the surface of the toner particles under a high temperature and high humidity environment (for example, at 28 ° C. and 85% RH environment), and the function as an abrasive is difficult to be exhibited. As a result, lubricant filming (formation of an excessive lubricant film) may occur on the surface of the image carrier. When lubricant filming occurs in the image carrier, in an image forming apparatus including a cleaning unit having a cleaning blade, the frictional force between the blade and the image carrier is increased, and the rotational torque (rotational load) of the image carrier is increased. Ascending, the device may stop. This is presumably because deposits (for example, discharge products) easily adhere excessively to the excessive lubricant film, thereby increasing the viscosity of the lubricant film.

  On the other hand, if the toner contains large-sized and irregularly shaped spherical silica particles having a particle size and a shape factor in the above ranges as external additives, the modified silica is used in a low-temperature and low-humidity environment (for example, 10 ° C., 15% RH). Compared with particles, spherical silica particles have fewer contacts with toner particles and tend to be excessively released from toner particles. When excessive spherical silica particles are released from the toner particles, in an image forming apparatus including a cleaning unit having a cleaning blade, the spherical silica particles pass through the cleaning blade and the surface of the image carrier is coated with silica (hereinafter referred to as “silica filming”). May occur). When silica filming occurs, a ghost (a phenomenon in which an image density change due to slipping of silica particles from a cleaning blade in a low temperature and low humidity environment) may occur.

  In contrast, if the toner includes both irregular shaped silica particles and spherical silica particles as external additives, the irregular shaped silica particles are more easily released from the toner particles in the low temperature and low humidity environment than in the high temperature and high humidity environment. , The amount of the released irregular shaped silica particles reaching the cleaning blade increases. The deformed silica particles are easily dammed by the cleaning blade because of their distorted shape compared to the spherical silica particles. The irregular shaped silica particles that have been dammed form a lump, thereby suppressing slipping of the spherical silica particles from the spherical silica particle cleaning blade. For this reason, even if spherical silica particles are used as an external additive, silica filming is suppressed in a low-temperature and low-humidity environment, and as a result, generation of ghost is suppressed.

On the other hand, in high-temperature and high-humidity environment, spherical silica particles are
There are few points of contact with the toner particles, and there is a tendency to be easily separated from the toner particles. For this reason, spherical silica is liberated from the toner even if it is difficult for the deformed silica to be liberated from the toner in a high-temperature and high-humidity environment. Demonstrates the function, suppresses the frictional force between the blade and the image carrier, suppresses the increase of the rotational torque (rotational load) of the image carrier, and the surface of the photoconductor is polished by the free spherical toner, and the lubricant filming also occurs. It is suppressed.

  As described above, in the image forming apparatus according to the present embodiment, in the image forming apparatus including the cleaning unit having the cleaning blade and the lubricant supply unit, the ghost in a low temperature and low humidity environment (for example, 10 ° C., 15% RH), and An increase in rotational torque of the image carrier is suppressed in a high temperature and high humidity environment (for example, in an environment of 28 ° C. and 85% RH).

  In particular, externally added toner particles having a volume average particle diameter of 5.0 μm or more and 9.0 μm or less are irregularly shaped silica particles having a number average particle diameter of 100 nm or more and 180 nm or less and spherical silica particles having a number average particle diameter of 100 nm or more and 180 nm or less. In this case, spherical silica particles are easily released from the toner particles in a low-temperature and low-humidity environment, silica filming occurs, and ghosts are easily generated. On the other hand, the irregular-shaped silica particles are not easily released from the toner particles in a high-temperature and high-humidity environment. The filming of the agent occurs, and the tendency that the rotation torque of the image carrier is easily increased is increased. However, even in this case, in the image forming apparatus according to the present embodiment, a ghost in a low temperature and low humidity environment and an increase in rotational torque of the image carrier in a high temperature and high humidity environment are suppressed.

  In the image forming apparatus according to the present embodiment, the charging step of charging the surface of the image holding member by the charging unit, the electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image holding member, The developing process for developing the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to the form, and transferring the toner image formed on the surface of the image carrier to the surface of the recording medium A transfer step for cleaning, a cleaning step for cleaning the surface of the image carrier with a cleaning blade, a step for supplying a lubricant to the surface of the image carrier with a lubricant supply means, and a toner image transferred to the surface of the recording medium. And an image forming method including a fixing step of fixing.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member Intermediate transfer system device that primarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the intermediate transfer body; then neutralizes the image on the surface of the image carrier after the toner image is transferred and before charging. A well-known image forming apparatus such as an apparatus provided with a neutralizing unit that performs neutralization by irradiating is applied.
In the case of an intermediate transfer type apparatus, the transfer unit includes, for example, an intermediate transfer body on which a toner image is transferred to the surface and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit, the cleaning unit, and the lubricant supply unit may be a cartridge structure (process cartridge) that is detachable from the image forming apparatus.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that can be attached to and detached from the image forming apparatus.

Above each unit 10Y, 10M, 10C, 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 is extended through each unit. The intermediate transfer belt 20 is provided around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, and travels in a direction from the first unit 10Y to the fourth unit 10K. Yes. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer body cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 so as to face the drive roll 22.
Each unit 10Y, 10M, 10C, 10K developing device (an example of developing means) 4Y, 4M, 4C, 4K has yellow, magenta, cyan, black in toner cartridges 8Y, 8M, 8C, 8K, respectively. Each toner is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, operation, and operation, a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction is formed here. The first unit 10Y will be described as a representative. The same reference numerals as magenta (M), cyan (C), and black (K) are attached to portions equivalent to the first unit 10Y instead of yellow (Y), so that the second to fourth units are added. Description of 10M, 10C, 10K is omitted.

  The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on the color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A photoconductor cleaning device having a primary transfer roll (an example of a primary transfer means) 5Y that transfers a toner image onto the intermediate transfer belt 20, and a cleaning blade 6Y-1 that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer ( An example of cleaning means) 6Y and a lubricant supply device (an example of lubricant supply means) 7Y for applying a lubricant to the surface of the photoreceptor 1Y are sequentially arranged.

  The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. A bias power source (not shown) for applying a primary transfer bias is connected to the primary transfer rolls 5Y, 5M, 5C, and 5K of each unit. Each bias power source changes the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

The photoconductor cleaning device 6Y includes a cleaning blade 6Y-1 that presses against the surface (circumferential surface) of the photoconductor 1Y and scrapes (scraps) residual toner after transfer from the photoconductor 1Y.
The cleaning blade 6Y-1 is a plate-like (blade-like) member and is made of, for example, an elastic material. Examples of the elastic material include thermosetting polyurethane rubber, silicone rubber, fluorine rubber, and ethylene / propylene / diene rubber.
For example, the cleaning blade 6Y-1 is disposed in a state in which the end on the proximal side of the photoreceptor 1Y is oriented opposite to the rotation direction of the photoreceptor 1Y.

  The lubricant supply device 7Y includes, for example, a solid lubricant and a rotating brush that contacts the lubricant and the surface (circumferential surface) of the photoreceptor 1Y and applies the lubricant to the photoreceptor 1Y. The rotating brush rotates as the photoconductor 1Y rotates, and a lubricant is applied to the surface of the photoconductor 1Y via the rotating brush.

The lubricant provided in the lubricant supply device 7Y is, for example, a well-known solid lubricant, and specific examples include fatty acid metal salts, fluororesins, and polyolefins.
Examples of fatty acid metal salts include metal salts of stearic acid such as zinc, cadmium, barium, lead, iron, nickel, cobalt, copper, aluminum, and magnesium; dibasic lead stearate: oleic acid, zinc, magnesium Metal salts such as iron, cobalt, copper, lead and calcium; metal salts of palmitic acid such as aluminum and calcium; lead caprylate, caproate, zinc linoleate, cobalt linoleate, calcium ricinoleate, zinc ricinoleate And cadmium ricinoleate; and mixtures thereof.
Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polyvinylidene fluoride (PVDF). ), Tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinyl fluoride (PVF), fluoroolefin-vinyl ether copolymer , Vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, and the like.
Examples of the polyolefin include paraffin wax, paraffin latex, and microcrystalline wax.
Among these, as the lubricant, zinc stearate is preferable from the viewpoint of the function as a lubricant, availability, and cost.

For example, when the area of the outer peripheral surface of the photoreceptor 1Y is 880 cm ² , the amount of lubricant supplied by the lubricant supply device 7Y is preferably 5 mg to 20 mg, more preferably 8 mg to 15 mg per 1000 revolutions.

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive base (for example, a volume resistivity of 1 × 10 ⁻⁶ Ωcm or less at 20 ° C.). This photosensitive layer usually has a high resistance (general resin resistance), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, the laser beam 3Y is irradiated from the exposure device 3 on the surface of the charged photoreceptor 1Y in accordance with yellow image data sent from a control unit (not shown). Thereby, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is developed and visualized as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as that charged on the photoreceptor 1Y and is held on the developer roll. . As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

  When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image, thereby causing the The toner image on the body 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to, for example, +10 μA by the control unit (not shown) in the first unit 10Y.

  After the toner image is transferred to the intermediate transfer belt 20, the photoconductor 1Y continues to rotate, and after the transfer from the photoconductor 1Y, the photoconductor 1Y and the cleaning blade 6Y-1 provided in the photoconductor cleaning device 6Y come into contact with each other. The residual toner is scraped off and removed. The toner removed from the photoreceptor 1Y is collected.

  The photosensitive member 1Y from which the residual toner has been removed by the photosensitive member cleaning device 6Y continues to rotate, and as the photosensitive member 1Y rotates, the rotating brush provided in the lubricant supply device 7Y rotates and lubricates via the rotating brush. An agent is applied to the surface of the photoreceptor 1Y.

The primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple ways through the first to fourth units includes the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and an image holding surface of the intermediate transfer belt 20. To a secondary transfer portion composed of a secondary transfer roll (an example of secondary transfer means) 26 arranged on the side. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, and the transfer bias is applied to the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

  Thereafter, the recording paper P is sent to a pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image. .

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. As the recording medium, in addition to the recording paper P, an OHP sheet and the like are also included.
In order to further improve the smoothness of the image surface after fixing, it is desirable that the surface of the recording paper P is smooth. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Preferably used.

  The recording paper P on which the color image has been fixed is unloaded to the discharge unit, and a series of color image forming operations is completed.

Hereinafter, an example of a process cartridge according to the present embodiment will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 and the photoconductor 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. The charged charging roll 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), a photoreceptor cleaning device 113 (an example of a cleaning unit), and a lubricant supply device (an example of a lubricant supply unit) 114 are integrated. These are combined and held in a cartridge.

The photoconductor cleaning device 113 includes a cleaning blade 113-1 that contacts the surface (circumferential surface) of the photoconductor 107 and scrapes (scraps) residual toner.
The lubricant supply device (an example of the lubricant supply unit) 114 is, for example, a solid lubricant 114S, a rotation that contacts the solid lubricant 114S and the surface (peripheral surface) of the photoconductor 107 and applies the lubricant to the photoconductor 107. And a brush 114B.

  In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (an example of a recording medium). Is shown.

  Next, the electrostatic charge image developer (hereinafter, the electrostatic charge image developer according to this embodiment) applied to the image forming apparatus according to this embodiment will be described in detail.

The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment (hereinafter, the toner according to the exemplary embodiment).
The electrostatic image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer mixed with the toner and a carrier.

[toner]
The toner according to the exemplary embodiment includes toner particles and an external additive.

(Toner particles)
The toner particles include, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

-Binder resin-
Examples of the binder resin include styrenes (eg, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (eg, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid). n-butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (for example, acrylonitrile, Methacrylonitrile, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, etc.) Emissions, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
As the binder resin, for example, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, non-vinyl resin such as modified rosin, a mixture of these with the vinyl resin, or these Examples also include a graft polymer obtained by polymerizing a vinyl monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of the polyester resin include known polyester resins.

  As a polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as a polyester resin, a commercial item may be used and what was synthesize | combined may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (eg, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.) Alicyclic dicarboxylic acids (for example, cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (for example, having 1 or more carbon atoms) 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, having 1 to 5 carbon atoms) alkyl esters.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K-1987 “Method for Measuring Transition Temperature of Plastics”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the polyester resin is preferably from 5,000 to 1,000,000, more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the polyester resin is preferably from 2,000 to 100,000.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed with a THF solvent using a Tosoh GPC / HLC-8120 as a measuring device and a Tosoh column / TSKgel Super HM-M (15 cm). The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

The polyester resin can be produced by a known production method. Specifically, for example, the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation.
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.

  The content of the binder resin is, for example, preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, and more preferably 60% by weight to 85% by weight with respect to the entire toner particles. Further preferred.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, or acridine series, xanthene series, azo series Various dyes such as benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole Can be mentioned.
A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.

  The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less with respect to the entire toner particles.

-Release agent-
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester types such as fatty acid esters and montanic acid esters Wax; and the like. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) according to the “melting peak temperature” described in JIS K-1987 “Method for measuring the transition temperature of plastics”.

  The content of the release agent is, for example, preferably 1% by mass to 20% by mass and more preferably 5% by mass to 15% by mass with respect to the entire toner particles.

-Other additives-
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core / shell structure toner particles include, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a binder resin. It is good to be comprised with the comprised coating layer.

  The volume average particle diameter (D50v) of the toner particles is preferably 3.0 μm or more and 9.0 μm or less, more preferably 5.0 μm or more and 9.0 μm or less, and further preferably 4 μm or more and 8 μm or less.

The various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter). The
In the measurement, 0.5 mg to 50 mg of a measurement sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is measured using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, a particle size that is 50% cumulative is defined as a volume average particle size D50v, a cumulative number average particle size D50p, and a particle size that is 84% cumulative is defined as a volume particle size D84v and a number particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following formula.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and is calculated as follows. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

(External additive)
As the external additive, irregular-shaped silica particles and spherical silica particles are applied.

-Deformed silica particles-
The irregular shaped silica particles are silica particles having a number average particle diameter of 100 nm to 180 nm and a shape factor SF2 of 130 to 180.

The number average particle diameter of the irregular shaped silica particles is from 100 nm to 180 nm, preferably from 110 nm to 160 nm, more preferably from 110 nm to 140 nm.
When the average particle size of the irregular shaped silica particles is 100 nm or more, the embedding in the toner particles is suppressed, and the function as an external additive (spacer function) is easily secured. On the other hand, when the average particle size of the irregular-shaped silica particles is 180 nm or less, an excessive amount from toner particles in a low-temperature and low-humidity environment (for example, 10 ° C., 15% RH environment) and a normal temperature and normal humidity environment (for example, 22 ° C., 55% RH). The amount of external addition to the toner particles is maintained, the function as an external additive (spacer function) is easily secured, and the deformed silica on the image carrier (photoreceptor) Migration and accompanying defects (external additive slipping through ghost / silica filming) are suppressed.

  The volume average particle diameter of the irregular-shaped silica particles is determined by observing 100 primary particles of irregular-shaped silica particles after externally adding (dispersing) the irregular-shaped silica particles to the toner particles with a SEM (Scanning Electron Microscope) apparatus. By analysis, the longest diameter and the shortest diameter of each particle are measured, and the sphere equivalent diameter is measured from the intermediate value. The 50% diameter (D50p) in the number-based cumulative frequency of the obtained equivalent sphere diameter is defined as the average particle diameter of the irregular shaped silica particles (that is, the number average particle diameter).

The shape factor SF2 of the irregularly shaped silica particles is 130 or more and 180 or less, preferably 130 or more and 160 or less, and more preferably 130 or more and 150 or less.
When the shape factor SF2 of the deformed silica particles is 130 or more, the contact area between the deformed silica particles and the toner particles increases, and the adhesion between the toner particles and the deformed silica particles increases, so that the deformed silica particles are released from the toner particles. As described above, the development of the spacer function of the irregularly shaped silica particles and the transfer to the image carrier (photoreceptor) are suppressed. In addition, when the image is transferred onto the image holding member (photosensitive member), by setting the shape factor SF2 to 130 or more, the scraping performance of the cleaning blade can be improved, and slipping of the irregular shaped silica particles can be prevented. On the other hand, when the shape factor SF2 of the irregular shaped silica particles is 180 or less, the irregular shaped silica particles are hardly lost even when a mechanical load is applied.

The shape factor SF2 of the irregular-shaped silica particles is determined by observing 100 primary particles of irregular-shaped silica particles after externally adding (dispersing) the irregular-shaped silica particles to the toner particles with a SEM (Scanning Electron Microscope) apparatus. Thus, SF2 is calculated by the following formula, and the average value is obtained.
Formula: Shape factor SF2 = “PM ² / (4 · A · π)” × 100
Here, in the formula, PM indicates the perimeter of the irregular shaped silica particle. A shows the projected area of deformed silica particles. π represents a circumference ratio.

Irregular silica particles, as long as it Motas the number average particle diameter and the shape factor SF2, silica, i.e. may be a particle composed mainly of SiO _2, may be non-crystalline in crystallinity. The irregular shaped silica particles may be particles produced from a silicon compound such as water glass or alkoxysilane, or particles obtained by pulverizing quartz.
Specifically, the irregular-shaped silica particles include sol-gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, famed silica particles obtained by a gas phase method, and fused silica particles. Among these, sol-gel silica particles are Good. The sol-gel silica particles as the deformed silica particles are obtained, for example, according to the method for producing silica particles described in JP 2012-006781 A.

  It is preferable that the surface of the irregular shaped silica particles is subjected to a hydrophobic treatment with a hydrophobic treatment agent. Examples of the hydrophobizing agent include known organosilicon compounds having an alkyl group (eg, methyl group, ethyl group, propyl group, butyl group). Specific examples include, for example, silazane compounds (eg, methyl trimethyl compound). Silane compounds such as methoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, and trimethylmethoxysilane, hexamethyldisilazane, tetramethyldisilazane, and the like. The hydrophobizing agent may be used alone or in combination. Among these hydrophobizing agents, organosilicon compounds having a trimethyl group such as trimethylmethoxysilane and hexamethyldisilazane are suitable.

  The external addition amount of the irregular shaped silica particles is, for example, preferably from 1.0% by mass to 2.0% by mass, and more preferably from 1.2% by mass to 1.6% by mass with respect to the toner particles.

-Spherical silica particles-
The spherical silica particles are silica particles having a number average particle diameter of 100 nm to 180 nm and a shape factor SF2 of 100 to 125.

The number average particle diameter of the spherical silica particles is from 100 nm to 180 nm, preferably from 110 nm to 170 nm, more preferably from 120 nm to 160 nm.
When the average particle diameter of the spherical silica particles is 100 nm or more, the embedding in the toner particles is suppressed, and the function as an external additive (spacer function) is easily secured. On the other hand, when the average particle diameter of the spherical silica particles is 180 nm or less, the toner particles are excessive from toner particles in a low-temperature and low-humidity environment (for example, 10 ° C., 15% RH environment) and a normal temperature and normal humidity environment (for example, 25 ° C., 55% RH). The amount of external addition to the toner particles is maintained, and the function as an external additive (spacer function) is easily secured.
The volume average particle diameter of the spherical silica particles is measured by the same method as that for the irregular shaped silica particles.

The spherical silica particles have a shape factor SF2 of 100 or more and 125 or less, preferably 100 or more and 120 or less, more preferably 100 or more and 110 or less.
When the shape factor SF2 of the spherical silica particles is within the above range, the function of the roller between the cleaning blade and the image carrier is easily exhibited, the frictional resistance between the two is reduced, and the rotational torque of the image carrier is increased. Is easily suppressed.
In addition, the shape factor SF2 of the spherical silica particles is measured by the same method as that for the irregular shaped silica particles.

Spherical silica particles, as long as it Motas the number average particle diameter and the shape factor SF2, silica, i.e. may be a particle composed mainly of SiO _2, may be non-crystalline in crystallinity. The irregular shaped silica particles may be particles produced from a silicon compound such as water glass or alkoxysilane, or particles obtained by pulverizing quartz.
Specifically, the irregular-shaped silica particles include sol-gel silica particles, aqueous colloidal silica particles, alcoholic silica particles, famed silica particles obtained by a gas phase method, and fused silica particles. Among these, sol-gel silica particles are Good. The sol-gel silica particles as the spherical silica particles are obtained, for example, according to a well-known method for producing monodispersed spherical silica particles.

  The spherical silica particles are also preferably subjected to a hydrophobic treatment on the surface with a hydrophobic treatment agent. Examples of the hydrophobizing agent include the same hydrophobizing agents described for the irregular-shaped silica particles.

  The external addition amount of the spherical silica particles is, for example, preferably from 0.8% by mass to 1.6% by mass, more preferably from 1.0% by mass to 1.5% by mass with respect to the toner particles. More preferably, the content is 2% by mass or more and 1.4% by mass.

-Others-
The external addition amount of the irregular shaped silica particles, the external addition amount of the spherical silica particles, and the supply amount of the lubricant per 1000 rotations of the image carrier are the ghost in the low temperature and low humidity environment, and the image retention in the high temperature and high humidity environment. From the viewpoint of suppressing an increase in rotational torque of the body, it is preferable to satisfy the following formula (1) and the following (2) (preferably (2-2), more preferably (2-3)).
Formula (1): (Y / X) × Z = a
Formula (2): 0.006 ≦ a ≦ 0.065
Formula (2-2): 0.010 ≦ a ≦ 0.050
Formula (2-3): 0.010 ≦ a ≦ 0.040

In Formula (1), Formula (2), Formula (2-2), and Formula (2-3), X is the external addition amount (% by mass) of the first silica particles with respect to the toner particles; Is the external addition amount (mass%) of the second silica particles to the toner particles, and Z is the supply amount of the lubricant (mg / cm ² ) supplied per 1000 rotations of the image carrier.

  The mass ratio between the external addition amount of the irregular shaped silica particles and the external addition amount of the spherical silica particles to the toner particles (external addition amount of the irregular shaped silica particles / external addition amount of the spherical silica particles) is a ghost in a low temperature and low humidity environment, and From the viewpoint of suppressing an increase in the rotational torque of the image carrier in a high temperature and high humidity environment, it is preferably 0.1 or more and 2.9 or less, preferably 0.3 or more and 2.5 or less, more preferably 0.5 or more. 2.0 or less.

  The total amount of the extraordinary silica particles and the spherical silica particles is determined from toner particles from the viewpoints of ghosting in a low-temperature and low-humidity environment, and suppression of an increase in rotational torque of the image carrier in a high-temperature and high-humidity environment and transfer maintenance. On the other hand, 1.4 mass% or more and 3.0 mass% or less are preferable, 1.6 mass% or more and 2.6 mass% or less are more preferable, and 1.8 mass% or more and 2.4 mass% are still more preferable.

  In addition, as an external additive, you may use together other well-known external additives other than a deformed silica particle and a spherical silica particle.

(Toner production method)
Next, a toner manufacturing method according to this embodiment will be described.
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner particles after the toner particles are manufactured.

The toner particles may be produced by any of a dry production method (for example, a kneading and pulverizing method) and a wet production method (for example, an aggregation coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). The production method of the toner particles is not particularly limited, and a known production method is adopted.
Among these, it is preferable to obtain toner particles by an aggregation and coalescence method.

Specifically, for example, when toner particles are produced by an aggregation coalescence method,
A step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step), and a resin particle dispersion (after mixing other particle dispersions as necessary) In the dispersion), the resin particles (other particles as necessary) are aggregated to form aggregated particles (aggregated particle formation step), and the aggregated particle dispersion in which the aggregated particles are dispersed is heated. Then, toner particles are manufactured through a process of fusing and coalescing the aggregated particles to form toner particles (fusing and coalescing process).

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing may be performed, for example, with a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

[Career]
There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. As a carrier, for example, a coated carrier in which the surface of a core made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; a porous magnetic powder is impregnated with a resin Resin impregnated type carriers; and the like.
Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

  Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

  Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer. Examples thereof include a polymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.
Note that the coating resin and the matrix resin may contain other additives such as a conductive material.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating layer forming solution obtained by dissolving the coating resin and, if necessary, various additives in an appropriate solvent may be mentioned. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include a dipping method in which the core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the core material, and a state in which the core material is suspended by flowing air. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed, a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to these Examples at all. The “part” means “part by mass” unless otherwise specified.

<Preparation of resin particle dispersion>
(Preparation of resin particle dispersion (1))
・ 30 mol parts of terephthalic acid ・ 70 mol parts of fumaric acid ・ 20 mol parts of bisphenol A ethylene oxide 2 mol adduct 80 mol parts of bisphenol A propylene oxide 2 mol adduct Stirrer, nitrogen inlet tube, temperature sensor, and rectification tower The above material was charged into a 5 liter flask equipped with the above, and the temperature was raised to 190 ° C. over 1 hour, and 1.2 parts of dibutyltin oxide was added to 100 parts of the material. The temperature was raised to 240 ° C. over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued at that temperature for 3 hours, and then the reaction product was cooled. Thus, a polyester resin (1) having a weight average molecular weight of 9700 and a glass transition temperature of 60 ° C. was synthesized.

The polyester resin (1) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 g / min. Simultaneously, separately prepared ammonia water having a concentration of 0.37% by mass was transferred to Cavitron CD1010 at a rate of 0.1 liter per minute while being heated to 120 ° C. with a heat exchanger.
The Cavitron CD1010 was operated under conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm ² to obtain a resin particle dispersion in which resin particles having a volume average particle diameter of 160 nm were dispersed. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 30% by mass to obtain a resin particle dispersion (1).

<Preparation of colorant dispersion>
(Preparation of colorant dispersion (1))
-Cyan pigment 50 parts (CI Pigment Blue 15: 3 manufactured by Dainichi Seika Kogyo Co., Ltd.)
1 part of anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 200 parts of ion-exchanged water The above materials are mixed and dispersed for 10 minutes using a homogenizer (Ultra Tlux T50 manufactured by IKA). A colorant dispersion (1) in which particles were dispersed (solid content 20% by mass) was obtained. The volume average particle diameter of the colorant particles was 168 nm.

<Preparation of release agent dispersion>
(Preparation of release agent dispersion (1))
・ 50 parts of paraffin wax (HNP-9 manufactured by Nippon Seiwa Co., Ltd.) 1 part of anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 200 parts of ion-exchanged water The above materials are mixed and heated to 95 ° C. Then, after being dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), the dispersion was dispersed with a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and the release agent dispersion (1) in which the release agent particles were dispersed. A solid content of 20% by mass was obtained. The volume average particle size of the release agent particles was 200 nm.

<Preparation of toner particles>
(Production of toner particles (P1))
-Resin particle dispersion (1) 310 parts-Colorant dispersion (1) 40 parts-Release agent dispersion (1) 50 parts-Anionic surfactant (TeycaPowerBN2060, 20% by weight aqueous solution manufactured by Teika) 2 parts The above materials were placed in a round stainless steel flask and dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA). Subsequently, 0.1N nitric acid was added to adjust the pH to 3.5, and 30 parts of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by mass was added. Subsequently, after dispersing at 30 ° C. using a homogenizer, the mixture was heated to 45 ° C. in a heating oil bath and held for 60 minutes. Thereafter, 100 parts of the resin particle dispersion (1) was gently added and held for 30 minutes.
Then, after adding 0.1N sodium hydroxide aqueous solution and adjusting pH to 8.5, it heated to 85 degreeC and continued for 180 minutes, continuing stirring. After confirming that the aggregated particles were fused with an optical microscope, it was cooled to 20 ° C. at a rate of 1 ° C./min.
After cooling, the particles were filtered off, washed thoroughly with ion exchange water, and dried to obtain toner particles (P1) having a volume average particle diameter (D50v) of 6.0 μm.

(Production of toner particles (P2))
In the production of the toner particles (P1), the holding time at 45 ° C. in the heating oil bath was changed from 60 minutes to 20 minutes to produce toner particles (P2) having a volume average particle diameter (D50v) of 5.0 μm. .

(Production of toner particles (P3))
In the production of the toner particles (P1), the temperature in the oil bath for heating was changed from 45 ° C. to 55 ° C. to produce toner particles (P3) having a volume average particle size of 9.0 μm.

<Preparation of silica particles>
(Silica particles (S1))
[Granulation process]
-Alkali catalyst solution preparation step [Preparation of alkali catalyst solution]-
Put 300 parts by mass of methanol and 47.8 parts by mass of 10% aqueous ammonia into a 3 L glass reaction vessel with a metal stir bar, dropping nozzle (Teflon (registered trademark) micro tube pump) and thermometer. The mixture was stirred and mixed to obtain an alkali catalyst solution.

-Particle generation step [Preparation of silica particle suspension]-
Next, the temperature of the alkali catalyst solution was adjusted to 25 ° C., and the alkali catalyst solution was purged with nitrogen. Thereafter, while stirring the alkaline catalyst solution, 450 parts of tetramethoxysilane (TMOS) and 270 parts of ammonia water having a catalyst (NH ₃ ) concentration of 4.44% were simultaneously added dropwise at the following supply amount to obtain silica particles. Suspension (silica particle suspension) was obtained.
Here, the supply amount of tetramethoxysilane was 7.08 parts / min, and the supply amount of 4.44% ammonia water was 4.25 parts / min.
The volume average particle diameter (D50v) of particles of the obtained silica particle suspension was 75 nm.

[Drying process]
Next, the obtained suspension of hydrophilic silica particles (hydrophilic silica particle dispersion) was dried by spray drying to remove the solvent to obtain hydrophilic silica particle powder.

[Hydrophobicization process]
100 parts of the obtained powder of hydrophilic silica particles is put into a mixer and stirred at 200 rpm while heating to 200 ° C. in a nitrogen atmosphere, and 30 parts of hexamethyldisilazane (HMDS) is added to the powder of hydrophilic silica particles. The solution was added dropwise and reacted for 2 hours. Thereafter, cooling and hydrophobic treatment of hydrophobic silica particles (S1) were obtained.

  The obtained hydrophobic silica particles (SA1) were added to toner particles, and SEM photography was performed on 100 primary particles of hydrophobic silica particles. Next, as a result of performing image analysis on the obtained SEM photograph, the primary particles of the hydrophobic silica particles (S1) had an average circularity of 0.750.

(Preparation of silica particles (SA1) to (SA10))
In the production of silica particles (S1), the total supply amount and supply amount of methanol, 10% ammonia water in the alkali catalyst solution preparation step, and tetramethoxysilane in the particle generation step, and the total supply amount and supply amount of 4.44% ammonia water. Were changed to the conditions shown in Table 1 to obtain hydrophobic silica particles (SA1) to (SA10) in the same manner as the silica particles (S1). Table 1 shows the number average particle diameter (D50p) and average circularity (SF2) of each silica particle.

(Preparation of silica particles (SB1) to (SB8))
In the production of silica particles (S1), the total supply amount and supply amount of methanol, 10% ammonia water in the alkali catalyst solution preparation step, and tetramethoxysilane in the particle generation step, and the total supply amount and supply amount of 4.44% ammonia water. The hydrophobic silica particles (SB1) to (SB8) were obtained in the same manner as the silica particles (S1) except that the conditions were changed to the conditions shown in Table 1. Table 1 shows the number average particle diameter (D50p) and average circularity (SF2) of each silica particle.

[Production of toner]
(Production of toner (T1))
Each particle is a toner particle so that the amount of silica particles (SA1) as silica particles A is 0.8% by mass (vs. toner particles) and the amount of silica particles (SB1) as silica particles B is 1.2% by mass. In addition to (P1), the mixture was mixed for 15 minutes at a peripheral speed of 30 m / s using a 5 liter Henschel mixer, and then coarse particles were removed using a sieve having an opening of 45 μm to prepare toner (T1).

(Production of toners (T2) to (T25))
According to Tables 2 to 3, toners (T2) to (T25) were produced in the same manner as the toner (T1) except that the type of toner particles and the type and amount of each silica particle were changed.

[Production of developer]
(Preparation of developer (D1))
4 parts of toner (T1) and 96 parts of carrier were stirred for 20 minutes at 40 rpm using a V-blender, and sieved with a sieve having an opening of 250 μm to prepare developer (D1). However, the following carrier 1 was used as a carrier.

-Production of carrier 1-
Ferrite particles (average particle size: 50 μm): 100 parts Toluene: 14 parts Styrene-methyl methacrylate copolymer (component ratio: 90/10): 2 parts Carbon black (R330: manufactured by Cabot Corporation): 0. Part 2 First, the above components other than the ferrite particles are stirred with a stirrer for 10 minutes to prepare a dispersed coating solution. Next, the coating solution and ferrite particles are placed in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes. After that, the carrier 1 was produced by further depressurizing while heating and degassing and drying.

(Production of developers (D2) to (D25))
Developers (D2) to (D25) were produced in the same manner as the developer (D1) except that the type of toner was changed according to Tables 2 to 3.

[Examples (1) to (16), Comparative Examples (1) to (9)]
Each developer shown in Tables 2 to 3 is supplied with an image forming apparatus “Color 1000 press (cleaning blade for cleaning the photoconductor and a lubricant (zinc stearate)) supplied to the photoconductor by Fuji Xerox Co., Ltd. The development apparatus of “equipped apparatus)” was filled.
The following evaluation was performed using this image forming apparatus. However, the supply amount of lubricant per 1000 revolutions of the photosensitive member (indicated as “lubricant supply rate” in the table) was set to the amount described in Tables 2 to 3. The results are shown in Tables 2 to 3.

[Evaluation]
The evaluation criteria are as follows.

(Rotational torque of photoconductor)
With the image forming apparatus of each example, 2000 halftone images having an image density of 10% were continuously output on A4 paper in a high temperature and high humidity environment (28 ° C., 85% RH). At that time, a torque meter is attached to the device to monitor the rotational torque. The evaluation was made based on the transition of the rotational torque and the presence or absence of an error display due to an increase in the rotational torque of the photosensitive member.
The evaluation criteria are as follows.
A: No error display, no torque increase
B: No error display, torque increase (Increase rate less than 50%)
C: No error display, torque increase (rate of increase of 50% or more)
D: Error display

(Evaluation of silica filming)
The image forming apparatus of each example continued to output 5000 attached charts (corresponding to an image density of 1%) in a low-temperature and low-humidity environment (10 ° C., 15% RH), and then the surface of the photoconductor was scanned with a laser microscope. Observation with “VK9500 (manufactured by Keyence Corporation)”, observation of the coating state of silica, and calculation of the ratio of the silica filming portion in the observed image When the ratio of the silica filming portion exceeds 10%, there is a practical problem.

(Evaluation of transfer maintenance)
The image forming apparatus of each example continuously outputs 10,000 half-tone images with an image density of 1% on A4 paper, and then the image density of the first and 10,000th sheets is set to X-Rite 938 (manufactured by X-Rite). ) And measured 5 points each to obtain an average value. By calculating the ratio (%) of the average value of the image density of the 10,000th sheet to the average value of the image density of the first sheet. The transfer maintenance was evaluated. If the transfer efficiency is less than 81%, there is a practical problem.

(Ghost evaluation)
The image forming apparatus of each example outputs 50 ghost evaluation charts such as attached images to A3 paper, measures the L * difference (ΔL *) between the ghost generation part and the non-generation part at that time, and evaluates the ghost. Went. If ΔL * exceeds 0.5, there is a practical problem.

(Evaluation of photoconductor scratches)
The image forming apparatus of each example output 20000 charts having an image density of 1%, and then the surface of the photoreceptor was observed. The evaluation criteria are as follows.
A: No scratches are observed on the photoreceptor B: Minor scratches are observed on the photoreceptor, but the image quality is not affected.
C: Scratches were observed on the photoreceptor and streaks were confirmed in the image.

  Tables 1 to 3 below list the details of each example, the evaluation results, and the characteristics of the silica particles measured by the method described above.

From the above results, in this example in which deformed silica particles and spherical silica particles were used in combination as external additives, Comparative Examples 5 and 8 using only deformed silica particles, and Comparative Examples 3 and 9 using only spherical silica particles were used. In comparison, it can be seen that both the rotational torque of the photoconductor and the evaluation of the ghost are good.
In addition, it can be seen that this example has good evaluations of lubricant filming, silica filming, transfer maintenance, and photoconductor scratches.

1Y, 1M, 1C, 1K, photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K, charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
6Y-1, 6M-1, 6C-1, 6K-1 Cleaning blades 7Y, 7M, 7C, 7K Lubricant supply device (an example of lubricant supply means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
28 Fixing device (an example of fixing means)
30 Intermediate transfer member cleaning device P Recording paper (an example of a recording medium)
107 photoconductor (an example of an image carrier)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
113-1 Cleaning blade 114 Lubricant supply device (an example of lubricant supply means)
114B Rotating brush 114S Solid lubricant 115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening 200 for exposure Process cartridge 300 Recording paper (an example of a recording medium)

Claims (5)

An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Toner particles, first silica particles having a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 130 to 180, and a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 100 or more And an electrostatic charge image developer formed on the surface of the image carrier by the electrostatic charge image developer. Developing means for developing the toner image as a toner image;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Lubricant supply means for supplying a lubricant to the surface of the image carrier;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: The external addition amount of the first silica particles, the external addition amount of the second silica particles, and the supply amount of the lubricant per 1000 rotations of the image carrier satisfy the following formulas (1) and (2). The image forming apparatus according to claim 1.
Formula (1): (Y / X) × Z = a
Formula (2): 0.006 ≦ a ≦ 0.065
(In Formula (1) and Formula (2), X is the external addition amount (mass%) of the first silica particles to the toner particles, and Y is the external addition amount of the second silica particles to the toner particles. Z is the amount of lubricant supplied (mg / cm ² ) supplied per 1000 rotations of the image carrier.   The mass ratio of the external addition amount of the first silica particles and the external addition amount of the second silica particles to the toner particles (external addition amount of the first silica particles / external addition amount of the second silica particles) is: The image forming apparatus according to claim 1, wherein the image forming apparatus is 0.1 or more and 2.9 or less.   The image forming apparatus according to claim 1, wherein the lubricant is zinc stearate. An image carrier,
Toner particles, first silica particles having a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 130 to 180, and a number average particle size of 100 nm to 180 nm and a shape factor SF2 of 100 or more And an electrostatic charge image developer formed on the surface of the image carrier by the electrostatic charge image developer. Developing means for developing the toner image as a toner image;
Cleaning means having a cleaning blade for cleaning the surface of the image carrier;
Lubricant supply means for supplying a lubricant to the surface of the image carrier;
And a process cartridge that is detachably attached to the image forming apparatus.