JP5879691B2 - Image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an image forming apparatus and an image forming method.

In a general electrophotographic image forming apparatus represented by a copying machine or a laser printer, for example, a toner image formed on a photosensitive layer on the surface of an image carrier is recorded on a recording sheet or the like through an intermediate transfer member. It is designed to be transferred to the medium. The toner remaining on the surface of the image carrier without being transferred is removed by a cleaning device.
As this cleaning device, a method of removing a toner remaining on the surface of the image holding member by pressing a cleaning blade against the surface of the image holding member is well known.

Here, in a system in which the toner remaining on the surface of the image holding member is removed by a cleaning blade, a technique for retaining (depositing) a cleaning aid or the like at the tip of the cleaning blade is known.
For example, Patent Documents 1 to 5 propose a technique for retaining a fluidizing agent in a wedge-shaped staying part (prenip tip part) in a range of 5 to 50 μm (20 to 100 μm).
Patent Document 6 proposes a technique for retaining a cleaning aid having a volume average particle size of 0.1 to 3 μm in a width of 50 to 100 μm.
Patent Document 7 proposes a technique in which a cleaning assistant is externally added in an amount of 10 to 40 wt% and is deposited in a layered manner.
Patent Document 8 proposes a technique for retaining a cleaning aid so as to be 50 to 100 μm.
Patent Document 9 proposes a technique for defining the toner speed distribution in the staying region and the width of the blocking region, and adding a functional agent to the developer and supplying it to the cleaning unit for deposition.

JP-A-8-297446 JP-A-8-297447 JP-A-8-297448 JP-A-8-297449 JP-A-8-297450 JP 2001-013837 A JP 2003-140468 A JP 2003-307985 A Japanese Patent Laid-Open No. 2006-18489

  The subject of this invention is providing the image forming apparatus which suppresses abrasion of an image holding body.

The above problem is solved by the following means. That is,
The invention according to claim 1
An image carrier,
A charging device for charging the surface of the image carrier;
An electrostatic latent image forming device that forms an electrostatic latent image on the surface of the image carrier charged by the charging device;
Difference value of total energy value measured in flow rate change test of powder rheometer [(measured value when rotational speed of rotor blade is 10 mm / s) − (measured value when rotational speed of rotor blade is 100 mm / s)] Is a developing device that contains a developer containing a toner of 187 mJ or more and 220 mJ or less, and develops the electrostatic latent image formed by the electrostatic latent image forming device with the developer;
A transfer device for transferring the image developed by the developing device and held on the surface of the image carrier to a recording medium;
A cleaning device for removing the toner remaining on the surface of the image carrier, a cleaning blade pressure against the surface of the image carrier is arranged below 1.0 gf / mm or more 10.0gf / mm A cleaning device;
An image forming apparatus comprising:

The invention according to claim 1
An image carrier,
A charging device for charging the surface of the image carrier;
An electrostatic latent image forming device that forms an electrostatic latent image on the surface of the image carrier charged by the charging device;
FRI (flow velocity index) [(measured value when the rotational speed of the rotary blade is 10 mm / s) / (measured value when the rotational speed of the rotary blade is 100 mm / s)] measured by the powder rheometer is 1. 70 to 2.10 and the difference value of the total energy value measured in the flow rate change test of the powder rheometer [(measured value when the rotational speed of the rotary blade is 10 mm / s) − (rotational speed of the rotary blade] Is measured at 100 mm / s)] is stored in a developer containing toner having a value of 187 mJ or more and 220 mJ or less, and the electrostatic latent image formed by the electrostatic latent image forming apparatus is developed with the developer. A developing device,
A transfer device for transferring the image developed by the developing device and held on the surface of the image carrier to a recording medium;
A cleaning device that removes the toner remaining on the surface of the image carrier, and includes a cleaning blade that is disposed at a pressure applied to the surface of the image carrier of 1.0 gf / mm to 10.0 gf / mm. A cleaning device;
An image forming apparatus comprising:

請 Motomeko 2 according the invention, the toner, and the toner particles, as an external additive to be externally added to the toner particles of claim 1 having silica particles, titania particles, and a fluorine resin particles, the Image forming apparatus.
The invention according to claim 3 is the image forming apparatus according to claim 1, wherein the toner includes toner particles and a flow accelerator externally added to the toner particles.

The invention according to claim 4
The image forming apparatus according to claim 3 , wherein the flow accelerator is a fluororesin particle.

The invention according to claim 5
The fluorine outer added amount of the resin particles, the image forming apparatus according to claim 2 or claim 4 1.50 mass% or less than 0.05 wt% with respect to the toner particles.

The invention according to claim 6
A charging step for charging the surface of the image carrier;
An electrostatic latent image forming step of forming an electrostatic latent image on the surface of the image carrier charged by the charging step;
FRI (flow velocity index) [(measured value when the rotational speed of the rotary blade is 10 mm / s) / (measured value when the rotational speed of the rotary blade is 100 mm / s)] measured by the powder rheometer is 1. 70 to 2.10 and the difference value of the total energy value measured in the flow rate change test of the powder rheometer [(measured value when the rotational speed of the rotary blade is 10 mm / s) − (rotational speed of the rotary blade] Development value for developing the electrostatic latent image formed in the electrostatic latent image forming step with a developer containing a toner having a measured value of 187 mJ or more and 220 mJ or less]
A transfer step of transferring the image developed in the development step and held on the surface of the image carrier to a recording medium;
A cleaning step of removing the toner remaining on the surface of the image carrier by a cleaning blade disposed at a pressure applied to the surface of the image carrier of 1.0 gf / mm to 10.0 gf / mm;
An image forming method comprising:

The invention according to claim 7 is the image according to claim 6 , wherein the toner includes toner particles and silica particles, titania particles, and fluororesin particles as external additives externally added to the toner particles. Forming method.
The invention according to claim 8 is the image forming method according to claim 6 , wherein the toner includes toner particles and a flow accelerator externally added to the toner particles.

The invention according to claim 9 is:
The image forming method according to claim 8 , wherein the glidant is fluororesin particles.

The invention according to claim 10 is:
The image forming method according to claim 7 or 9 , wherein an external addition amount of the fluororesin particles is 0.05% by mass or more and 1.50% by mass or less with respect to the toner particles.

According to the invention according to claim 1 or 2 , as compared with the case where a toner satisfying the above range of the difference value or FRI (flow rate index) of the total energy value and a cleaning blade where the applied pressure satisfies the above range are not combined. An image forming apparatus that suppresses wear of the image carrier can be provided.
According to the third and fourth aspects of the invention, it is possible to provide an image forming apparatus that suppresses the wear of the image carrier as compared with the case where the toner configured to include toner particles and the flow accelerator is not applied.
According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus that suppresses the wear of the image carrier as compared with the case where the external addition amount of the fluororesin particles as the flow accelerator is out of the above range.

According to the invention according to claim 6 or 7 , as compared with the case where a toner satisfying the above range of the difference value or FRI (flow rate index) of the total energy value and a cleaning blade where the applied pressure satisfies the above range are not combined. An image forming method for suppressing wear of the image carrier can be provided.
According to the eighth and ninth aspects of the present invention, it is possible to provide an image forming method that suppresses the wear of the image carrier as compared with the case where toner including toner particles and a flow accelerator is not applied.
According to the tenth aspect of the present invention, it is possible to provide an image forming method that suppresses the wear of the image carrier as compared with the case where the external addition amount of the fluororesin particles as the flow accelerator is outside the above range.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows a cleaning apparatus. It is a schematic diagram for demonstrating the pressurization force of the cleaning blade of a cleaning apparatus. It is the schematic diagram which expanded the circumference | surroundings of the cleaning blade of the cleaning apparatus. It is the schematic diagram which expanded the circumference | surroundings of the front-end | tip part of the cleaning blade of a cleaning apparatus. It is a schematic diagram for demonstrating the state of the external additive in a blade prenip when the conventional toner is applied. FIG. 5 is a schematic diagram for explaining a state of an external additive in a blade prenip when a toner having improved dynamic fluidity is applied. It is the image which image | photographed the blade prenip with the camera when the conventional toner was applied. It is the image which image | photographed the blade prenip when the toner which improved the dynamic fluidity was applied. It is a graph which shows the relationship between FRI (ratio) and photoconductor abrasion rate obtained in evaluation experiment. It is a graph which shows the relationship between FRI (difference value) and photoconductor abrasion rate obtained in evaluation experiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the figure, when an arrow UP is shown, it is an upward direction, and when an arrow IN is shown, it is an inward direction.
In addition, components having the same function are denoted by the same reference numerals throughout the drawings, and description thereof may be omitted.

  FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment. FIG. 2 is a schematic configuration diagram illustrating the cleaning device.

The configuration of the image forming apparatus 10 according to the present embodiment will be briefly described, but portions common to the respective colors will be described without adding alphabetic characters indicating the respective colors after the reference numerals.
For example, as shown in FIG. 1, the image forming apparatus 10 according to the present embodiment transfers toner images of each color based on input image data to an endless belt-shaped intermediate transfer belt 24 described later to form an image. The four-tandem image forming means 12 is provided.

  The image forming unit 12 outputs, for example, yellow (Y), magenta (M), cyan (C), and black (K) images in order from the upstream side in the conveyance direction of the recording paper P that is an example of a recording medium. The electrophotographic image forming units 14Y, 14M, 14C, and 14K are provided. The image forming units 14Y to 14K are separated from each other along the moving direction of the intermediate transfer belt 24 (indicated by an arrow B). It is installed side by side.

  Each of the image forming units 14Y to 14K includes, for example, photoconductors 16Y to 16K as image carriers, and the photoconductors 16Y to 16K are, for example, the surface (circumferential surface) of a conductive metal cylinder. In addition, a photosensitive layer made of an organic photoconductor or the like is laminated, and is driven to rotate in a direction indicated by an arrow A (clockwise direction) at a target process speed.

  The photosensitive layer is, for example, a function-separated type in which a charge generation layer and a charge transport layer are sequentially laminated, and has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam. ing. Further, it is desirable that the diameter of each of the photoconductors 16Y to 16K is, for example, in a range from 20 mm to 100 mm.

  Around each of the photoconductors 16Y to 16K, for example, charging devices 18Y to 18K as charging devices for charging the surface (circumferential surface) of the photoconductor 16 sequentially from the upstream side in the rotation direction, and the charged photoconductor 16Y. Exposure devices 20Y to 20K that irradiate the surface (circumferential surface) of 16K to a laser beam (image light) based on color-separated image data (image signal) to form an electrostatic latent image by exposure, and charged development Tension is applied from the inner peripheral surface side to the developing devices 22Y to 22K that transfer (develop) the developer (developer including toner) to an electrostatic latent image to form a toner image, and a path that contacts the photoconductors 16Y to 16K. An endless belt-shaped intermediate transfer belt 24 supported while being applied, primary transfer rolls 26Y to 26K that transfer the toner images formed on the photoreceptors 16Y to 16K to the intermediate transfer belt 24, and a feeling after the primary transfer. And a cleaning device 28Y~28K for removing residual toner TN1 remaining on the surface of the body 16Y～16K, are arranged.

  For example, the cleaning devices 28Y to 28K are provided with cleaning blades 60Y to 60K that are pressed against the surfaces (circumferential surfaces) of the photoreceptors 16Y to 16K and scrape (scrap off) the transfer residual toner TN1 from the photoreceptors 16Y to 16K. It has been. The cleaning device 28 (cleaning blade 60) will be described in detail later.

  The primary transfer rolls 26Y to 26K are disposed, for example, on the inner side of the intermediate transfer belt 24, and are provided at positions facing the photoreceptors 16Y to 16K, respectively. A contact portion between the photoreceptors 16Y to 16K and the intermediate transfer belt 24 by the primary transfer rolls 26Y to 26K is a primary transfer portion (primary transfer position) T1.

  Further, for example, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 26Y to 26K. Further, each bias power source is controlled by a control unit (not shown), for example, so that the primary transfer bias applied to each of the primary transfer rolls 26Y to 26K is changed. Further, the charging devices 18Y to 18K are, for example, roll-shaped contact chargers, but non-contact chargers such as scorotrons and solid-state dischargers may be used.

  On the other hand, the intermediate transfer belt 24 as an intermediate transfer member includes, for example, primary transfer rolls 26Y to 26K, a drive roll 32 that is rotationally driven by a drive source (not shown), a driven roll 33, and a secondary transfer unit (secondary transfer unit). Position) It is wound around the back roll 34 arranged at T2, and is rotated (circulated) in the direction of arrow B in synchronization with the rotation of the photosensitive member 16.

The intermediate transfer belt 24 has a surface resistivity of, for example, dispersed in a resin material such as polyimide, polyamideimide, polycarbonate, or fluorine resin with a substance for imparting conductivity such as carbon or an ion conductive substance. It is formed by adjusting to about 10 ¹⁰ Ω / □ or more and about 10 ¹² Ω / □ or less (measurement voltage: 100 V).

  The secondary transfer roll 36 that transfers the toner image on the intermediate transfer belt 24 onto, for example, the recording paper P conveyed by the conveyance mechanism 42 is located at a position facing the back roll 34 across the intermediate transfer belt 24. Is provided. A contact portion between the secondary transfer roll 36 and the intermediate transfer belt 24 is a secondary transfer portion (secondary transfer position) T2.

  The image forming apparatus 10 also includes a toner removing device (cleaning device) that removes the transfer residual toner NT1 remaining on the intermediate transfer belt 24 after the toner image is transferred onto the recording paper P by the secondary transfer roll 36, for example. ) 38 and a fixing device 40 for fixing the toner image transferred onto the recording paper P by the secondary transfer roll 36.

  The transport mechanism 42 includes, for example, a pickup roll 46 that transports the recording paper P stored in the paper feed unit 44 one by one, a guide member 50 and a pair of transport rolls 48 that are provided in the transport path of the recording paper P, A conveyance belt 56 is disposed downstream of the secondary transfer roll 36 in the conveyance path of the recording paper P and upstream of the fixing device 40 in the conveyance path of the recording paper P and is wound around the guide rolls 52 and 54. And a pair of paper discharge rolls 58 provided on the downstream side of the fixing device 40, a paper discharge unit (not shown), and the like.

  By the transport mechanism 42, for example, the recording paper P accommodated in the paper supply unit 44 is transferred to the secondary transfer unit (secondary transfer position) where the secondary transfer roll 36 and the back roll 34 face each other with the intermediate transfer belt 24 interposed therebetween. ) Transported to T2, transported from the secondary transfer portion (secondary transfer position) T2 to the fixing device 40, and transported from the fixing device 40 to the paper discharge portion.

  For example, the image forming apparatus 10 configured as described above operates as follows to form an image. Since the image forming units 14Y to 14K for the respective colors have the same configuration, an example of an operation for forming a yellow toner image by the image forming unit 14Y will be described here.

  First, the surface of the photoconductor 16Y is charged to a potential of, for example, −600 V or less and −800 V or less by the charging device 18Y. The surface of the charged photoreceptor 16Y is irradiated with a laser beam by the exposure device 20Y in accordance with, for example, yellow image data sent from the control unit. That is, an electrostatic latent image of a yellow print pattern is formed on the photosensitive layer of the photoreceptor 16Y.

  The electrostatic latent image is, for example, an image formed on the surface (photosensitive layer) of the photoconductor 16Y by charging. In the photoconductive layer, the specific resistance of the portion irradiated with the laser beam decreases, and the photoconductor 16Y. This is a so-called “negative latent image” formed by the fact that the charged charge flows on the surface of the film while the charge remaining in the portion not irradiated with the laser beam remains.

  Thus, the electrostatic latent image formed on the photoconductor 16Y is conveyed to the development position by the rotation of the photoconductor 16Y, for example. At this development position, the electrostatic latent image on the photoreceptor 16Y is converted into a visible image (toner image) by the developing device 22Y.

  For example, the yellow toner is triboelectrically charged by being stirred inside the developing device 22Y, and has a charge of the same polarity (−) as the charge on the surface of the photoreceptor 16Y. Accordingly, when the surface of the photoconductor 16Y passes through the developing device 22Y, for example, yellow toner is electrostatically attached only to the latent image portion on the surface of the photoconductor 16Y, and the latent image becomes yellow toner. It is developed by. Thereafter, the photoreceptor 16Y continues to rotate, and the toner image developed on the surface thereof is conveyed to the primary transfer portion (primary transfer position) T1.

  When the yellow toner image on the surface of the photoreceptor 16Y is conveyed to the primary transfer portion (primary transfer position) T1, for example, a primary transfer bias is applied to the primary transfer roll 26Y, and static electricity is directed from the photoreceptor 16Y to the primary transfer roll 26Y. The force acts on the toner image, and the toner image on the surface of the photoreceptor 16 </ b> Y is transferred to the surface of the intermediate transfer belt 24. The primary transfer bias applied at this time is, for example, a polarity (+) opposite to the polarity (−) of the toner, and in the image forming unit 14Y, constant current control is performed, for example, to +20 μA or more and +30 μA or less by the control unit.

  The transfer residual toner TN1 on the surface of the photoreceptor 16Y is cleaned by, for example, the cleaning device 28Y. Further, the primary transfer bias applied to the primary transfer rolls 26M to 26K of the image forming units 14M to 14K is also controlled in the same manner as described above, for example. Thus, the intermediate transfer belt 24 onto which the yellow toner image has been transferred by the image forming unit 14Y is sequentially conveyed to, for example, the remaining color image forming units 14M to 14K, and transferred so that the toner images of the respective colors are superimposed. (Multiple transfer).

  The intermediate transfer belt 24 on which the toner images of all colors have been transferred in multiple passes through the image forming units 14Y to 14K is, for example, circulated and conveyed in the direction of arrow B shown in the figure, and the inner surface (back surface) of the intermediate transfer belt 24. To the secondary transfer portion (secondary transfer position) T2 constituted by the back roll 34 in contact with the secondary transfer roll 36 disposed on the toner image holding surface side of the intermediate transfer belt 24.

  On the other hand, the recording paper P is fed, for example, between the secondary transfer roll 36 and the intermediate transfer belt 24 by the transport mechanism 42, and a secondary transfer bias is applied to the secondary transfer roll 36. The secondary transfer bias applied at this time is, for example, the polarity (+) opposite to the polarity (−) of the toner, and the electrostatic force from the intermediate transfer belt 24 toward the recording paper P acts on the toner image, and the intermediate transfer The toner image on the surface of the belt 24 is transferred to the surface of the recording paper P.

  The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer portion (secondary transfer position) T2, for example, and is a constant voltage. It is controlled. Thereafter, for example, the recording paper P is sent to the fixing device 40, the toner image is heated and pressurized, and the color-superposed (multi-transferred) toner image is melted and permanently fixed on the surface of the recording paper P. Is done. Thus, the recording paper P on which the image has been fixed is carried out, for example, toward a paper discharge unit, and a series of image forming operations is completed.

Next, the developer will be described.
Examples of the developer include a two-component developer including a toner and a carrier, but may be a one-component developer composed only of toner.
The toner is 1) the difference value of the total energy value measured in the flow rate change test of the powder rheometer [(measured value when the rotational speed of the rotary blade is 10 mm / s) − (the rotational speed of the rotary blade is 100 mm / (measured value when s)] is 220 mJ or less, or 2) FRI (flow velocity index) measured by a powder rheometer [(measured value when the rotational speed of the rotating blade is 10 mm / s) / ( The measured value when the rotational speed of the rotor blades is 100 mm / s)] is 2.10 or less.
In the following description, FRI (flow velocity index) is referred to as “FRI (ratio)”, and the difference value of the total energy value is referred to as “FRI (difference value)”.

When the toner satisfies this FRI (difference value) or FRI (ratio), the wear of the photosensitive member 16 is suppressed.
The FRI (difference value) is 220 mJ or less, preferably 170 mJ or more and 215 mJ or less, and more preferably 180 mJ or more and 210 mJ or less.
The FRI (ratio) is 2.10 or less, preferably 1.6 or more and 2.05 or less, and more preferably 1.7 or more and 2.00 or less.
In order to satisfy the FRI (difference value) or FRI (ratio) of the toner, for example, a method of externally adding a flow accelerator as an external additive to the toner particles can be mentioned.

Here, FRI (difference value) or FRI (ratio) indicates the dynamic fluidity of the toner.
A powder rheometer FT4 manufactured by Freeman Technology (UK) is used to measure the dynamic fluidity of the toner.
The powder rheometer measures the rotational torque and vertical load of the rotating blades (blades) obtained by the rotating blades (blades) rotating in the powder at the same time, and integrates the energy gradient with respect to the moving distance. The value is obtained as total energy and used as an indicator of dynamic fluidity. There are four types of dynamic fluidity tests performed with this device: stability test, flow rate change test, compression test, and aeration test. The dynamic fluidity index that can be measured is the basic fluidity energy BFE ( Basic Flowability Energy) and stability index SI (Stability Index), flow rate index FRI (Flow Rate Index) in flow rate change test, compression index CI (Consolidation Index) in compression test, aeration index AR (Aeration Ratio) in aeration test, etc. All are automatically measured by a personal computer connected to the device.

Specifically, the measurement of the dynamic fluidity of the toner is as follows.
First, in an environment of a temperature of 22 ° C. and a humidity of 55%, 180 g of toner is put into a 160 ml split container attached to the powder rheometer and attached to the main body. In order to improve the reproducibility of the measurement, conditioning is performed seven times to adjust the state of the toner, and then excess toner is removed by grinding with a split container.
The conditioning cycle is performed automatically. After that, if you click Start on the computer, the above test is automatically performed, and each index is calculated and output. However, when performing a ventilation test, it is necessary to connect an automatic ventilation measurement kit.

Among the obtained measured values, those having a high correlation with the wear of the photosensitive member 16 are FRI (ratio) and FRI (difference value).
FRI (ratio) is the measurement value obtained by changing the rotation speed of the rotor blade from 100 mm / s → 70 mm / s → 40 mm / s → 10 mm / s (the rotation speed of the rotor blade is 10 mm / s). Measured value) / (measured value of rotating blade rotation speed of 100 mm / s). FRI (ratio) means that the one close | similar to 1 has shown the dynamic fluidity stabilized with respect to the flow rate change.
On the other hand, FRI (difference value) is not the above-mentioned ratio but is obtained by (measured value of rotating blade rotation speed of 10 mm / s) − (measured value of rotating blade rotation speed of 100 mm / s). .

Next, a specific configuration of the toner will be described.
The toner includes, for example, toner particles and an external additive.

The toner particles will be described.
The toner particles include, for example, a binder resin and, if necessary, other additives such as a colorant and a release agent.

Examples of the binder resin include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride copolymer. Typical examples include polyethylene resin, polypropylene resin, and polyester resin.
Examples of the binder resin include polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, and paraffin wax.

Examples of other additives include a colorant, a release agent, a magnetic material, a charge control agent, and an inorganic powder.
Examples of the colorant include magnetic powder (eg, magnetite, ferrite, etc.), carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.
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. Typical examples include waxes.

The characteristics of the toner particles will be described.
The toner particles have an average shape factor (shape factor = (ML ² / A) × (π / 4) × 100), and ML represents the maximum length of the particles, where A represents the maximum length of the particles (Representing the projected area) is preferably from 100 to 150, more preferably from 105 to 145, and even more preferably from 110 to 140.

  For example, the toner particles preferably have a volume average particle diameter D50v of 2.0 μm to 10 μm, preferably 2.0 μm to 6.5 μm, more preferably 2.0 μm to 5.5 μm, and more preferably 2.0 μm. It is particularly desirable that it is not less than 4.5 μm. The lower limit of the volume average particle diameter D50v is desirably 2.5 μm or more, and more desirably 3.0 μm or more.

The external additive will be described.
As the external additive, for example, inorganic particles are applied.
Examples of inorganic particles as external additives include SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, _{ZrO 2, CaO · SiO 2,} K 2 O · (TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.

  The surface of the inorganic particles as an external additive may be previously hydrophobized. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.

  The external addition amount of the inorganic particles as the external additive is, for example, preferably from 0.5% by mass to 5.0% by mass and preferably from 1.0% by mass to 3.0% by mass with respect to the toner particles. .

Examples of the external additive include a glidant.
Preferable examples of the glidant as the external additive include particles such as a fluororesin, a silicone resin, and a polypropylene resin. Of these, fluororesin particles are preferable as the glidant.

  Examples of the fluororesin constituting the glidant include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), Polyvinylidene fluoride (PVDF), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinyl fluoride (PVF), fluoro Examples thereof include an olefin-vinyl ether copolymer, a vinylidene fluoride-tetrafluoroethylene copolymer, and a vinylidene fluoride-hexafluoropropylene copolymer.

  The volume average particle size of the glidant as the external additive is, for example, preferably from 0.1 μm to 10 μm, desirably from 0.5 μm to 8 μm, and more desirably from 1 μm to 6 μm.

The external addition amount of the glidant (particularly fluororesin particles) as the external additive is preferably 0.05% by mass or more and 1.50% by mass or less, and 0.08% by mass or more with respect to the toner particles. 1.0 mass% or less is desirable, and 0.1 mass% or more and 0.8 mass% or less is more desirable.
When the external additive amount of the glidant as the external additive is in the above range, the toner easily satisfies the above FRI (difference value) or FRI (ratio) range, so that wear of the photoconductor 16 is easily suppressed. .
Note that if the amount of the external additive of the glidant as an external additive is too large, the toner charging characteristics may be affected.

As the external additive, among the inorganic particles and the glidant, in particular, a glidant (particularly fluororesin particles) is preferably used in combination with silica particles (SiO ₂ ) and titania particles (TiO ₂ ).

A method for producing toner will be described.
First, the toner particles are not particularly limited by the production method. For example, the toner particles are kneaded and pulverized by adding, for example, a binder resin, a colorant and a release agent, and a charge control agent as necessary. Method: Method of changing the shape of particles obtained by kneading and pulverization method by mechanical impact force or thermal energy; Emulsion polymerization of polymerizable monomer of binder resin, and formed dispersion and colorant And a release agent and, if necessary, a dispersion of a charge control agent or the like, and agglomeration, heat fusion to obtain toner particles; an emulsion polymerization aggregation method; a polymerizable monomer for obtaining a binder resin; A suspension polymerization method in which a solution of a colorant and a release agent, if necessary, a charge control agent is suspended in an aqueous solvent for polymerization; a binder resin, a colorant and a release agent, and optionally charged A solution manufactured by a suspension method, etc., in which a solution of a control agent is suspended in an aqueous solvent and granulated. Over particles are used.

  Further, a known method such as a production method in which the toner particles obtained by the above method are used as a core, and agglomerated particles are further adhered and heated and fused to give a core-shell structure is used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  The toner is produced by mixing the toner particles and the external additive with a Henschel mixer or a V blender. Further, when the toner particles are produced by a wet method, they may be externally added by a wet method.

Next, the carrier will be described.
There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. Examples of the carrier include a resin-coated carrier, a magnetic dispersion carrier, a resin dispersion carrier, and the like.

  The mixing ratio (weight ratio) between the toner and the carrier in the two-component developer is preferably in the range of, for example, toner: carrier = 1: 100 to 30: 100, and in the range of 3: 100 to 20: 100. Is more desirable.

Next, the cleaning device 28 will be described in detail.
For example, as shown in FIG. 2, the cleaning device 28 includes a housing 30 that is disposed in the vicinity of the surface (circumferential surface) of the photoconductor 16 and opens on the side facing the surface of the photoconductor 16.

  The cleaning device 28 may be configured as, for example, at least a photoconductor unit (image holding unit) 27 integrated with the photoconductor 16, and the image forming apparatus 10 is in the state of the photoconductor unit 27. On the other hand, it is configured to be attached and detached. Further, the cleaning device 28 may be unitized as a single unit, and may be configured to be attached to and detached from the image forming apparatus 10. Further, the cleaning device 28 is attached to the image forming apparatus 10 so as not to be attachable and detachable. 16 may be configured to be attached to and detached from the image forming apparatus 10.

  On the inner surface of the open end 30B on the lower side of the housing 30, for example, a seal member 72 that prevents waste toner or the like accommodated in the cleaning device 28 from leaking outside is disposed. That is, the seal member 72 is configured to extend toward the photoconductor 16 so as to close a gap between the photoconductor 16 and the housing 30 and does not contact the photoconductor 16. For the seal member 72, for example, a thermoplastic polyurethane film having a thickness of 0.2 mm is used.

  Further, on the lower side in the housing 30, for example, a screw 74 that conveys the collected waste toner or the like to a waste toner discharge portion (not shown) provided outside the housing 30 is disposed. For example, a cleaning blade 60 is disposed downstream of the seal member 72 of the housing 30 in the rotation direction (arrow A direction) of the photosensitive member 16.

  That is, for example, the base (one end side) 62 of the cleaning blade 60 is provided on the lower outer surface of the sheet metal 76 as a supporting base material provided in the axial direction of the photosensitive member 16 and having an “L” shape in cross section. The sheet metal 76 is fixed to the upper outer surface of the housing 30 by a set screw 78.

  The cleaning blade 60 is formed in a plate shape (blade shape) made of an elastic material, for example, and has a thickness of 2.0 mm and a free length (a width (not fixed to the sheet metal 76) ( The length in the vertical direction)) is 10.0 mm, and the axial length of the photosensitive member 16 is 330 mm. Examples of the elastic material include thermosetting polyurethane rubber that is excellent in mechanical properties such as wear resistance, chipping resistance, and creep resistance. Examples of the elastic material also include functional rubber materials such as silicone rubber, fluorine rubber, and ethylene / propylene / diene rubber.

  For example, the cleaning blade 60 sensitizes the edge portion 65 of the tip portion (lower end portion) 64 in a state where the tip portion (lower end portion) 64 faces the direction opposite to the rotation direction (arrow A) of the photosensitive member 16. The body 16 is disposed so as to face the body 16.

The pressure N (see FIG. 3) of the cleaning blade 60 is determined to be a value that satisfies the cleaning property for a long time, for example, the blade free length L, the blade thickness t, the Young's modulus (hardness) of the blade material, and the blade setting angle θ. (Contact angle α), blade biting amount d (to the photosensitive member), toner specification used in the image forming apparatus, specification of the photosensitive member 16, charging method, members contacting around the photosensitive member 16, blade required life In the present embodiment, for example, a range of 1.0 gf / mm to 10.0 gf / mm (preferably 1.2 gf / mm to 8.0 gf / mm, more preferably 1.5 gf / mm). mm to 6.0 gf / mm).
If the applied pressure N of the cleaning blade 60 is less than 1.0 gf / mm, cleaning failure is likely to occur due to insufficient applied pressure. If the pressure N of the cleaning blade 60 exceeds 10.0 gf / mm, the rotational torque of the photoconductor 16 is increased by the cleaning blade 60, which is not practical.
Here, the pressure N of the cleaning blade 60 is calculated by the following equation (see FIG. 3).
Formula: N = dEt ³ / 4L ³
Here, d is the blade biting amount, E is the blade Young's modulus, t is the blade thickness, and L is the blade free length.

  The pressurizing method of the cleaning blade 60 (pressurizing method for the photosensitive member 16) may adopt a constant displacement method having a simple structure and a low cost, and is not limited to the constant displacement method. A constant load method with little change may be adopted.

Here, in the cleaning device 28, when cleaning is performed with the cleaning blade 60 disposed in the range of the pressure applied to the photosensitive member 16, the contact portion between the cleaning blade 60 (the edge portion 65) and the photosensitive member 16. The toner (toner particles and external additives) is accumulated on the upstream side (hereinafter referred to as blade pre-nip).
FIG. 4 is an enlarged view of the periphery of the cleaning blade 60 of the cleaning device 28. TN1 is the transfer residual toner, and TN2 is the toner accumulated in the blade prenip. FIG. 5 is an enlarged view of the inside of the circle in FIG. 4 in order to explain the blade prenip in detail.

  As shown in FIGS. 4 and 5, the edge portion 65 of the cleaning blade 60 is moved by the dynamic frictional force acting on the surface of the photosensitive member 16 and the edge portion 65 of the cleaning blade 60 during the rotation of the photosensitive member 16. It is deformed into a shape pulled in the rotation direction (arrow A) and becomes a wedge shape with a small tip angle.

At this time, what is important is that, as a result of detailed observation and analysis of the blade prenip, it has been found that the following phenomenon occurs.
When the rotation of the photoconductor 16 continues, external additives having a relatively small particle size begin to gather in the blade prenip (indicated by G in FIG. 5), and the particle size is increased upstream in the rotation direction of the photoconductor 16. Large toner (toner particles) collects (indicated by TN2 in FIG. 5). In the region where the external additive is gathered, the pressing force is applied by the toner carried from the upstream side in the rotation direction of the photosensitive member 16, so that the external additive is in a filled state (packing state). A pressing force is applied to the surface of the photoconductor 16 (indicated by the arrow Y1 in FIG. 5) when pressed by 65.
As a result, the surface of the photoreceptor 16 is polished by an external additive (for example, hard inorganic particles such as silica particles) and wear progresses.
Note that toner (toner particles) gathers to some extent on the upstream side of the rotating direction of the photoreceptor 16 in the blade pre-nip, and after that, can no longer stay in the pre-nip and gradually fall by gravity (toner particles: TN3 in FIG. 5). Is generated, and once stored in the housing 30, it is discharged by the screw 74.

Although the case where the cleaning blade 60 faces downward has been described, it has been found that the same phenomenon has occurred as a result of separately observing and analyzing the case in the upward direction separately.
Specifically, as shown in FIG. 6, while the photosensitive member 16 is rotating, the edge portion 65 of the cleaning blade 60 is moved to the photosensitive member due to the dynamic frictional force acting on the surface of the photosensitive member 16 and the edge portion 65 of the cleaning blade 60. It is deformed into a shape pulled in 16 rotation directions, and becomes a wedge shape with a small tip angle.
When the rotation of the photosensitive member 16 continues, as in the case where the cleaning blade 60 faces downward, external additives having a relatively small particle diameter begin to gather in the blade prenip (indicated by G in FIG. 6). Toner (toner particles) having a large particle diameter collects on the upstream side in the rotation direction of the photoconductor 16 (indicated by TN2 in FIG. 6).
In the region where the external additive is gathered, the pressing force is applied by the toner carried from the upstream side in the rotation direction of the photosensitive member 16, so that the external additive is in a filled state (packing state). A pressing force is applied to the surface of the photoreceptor 16 (indicated by the arrow Y1 in FIG. 6) when pressed by 65.
As a result, the surface of the photoreceptor 16 is polished by an external additive (for example, hard inorganic particles such as silica particles) and wear progresses.
In addition, on the upstream side of the rotating direction of the photosensitive member 16 in the blade prenip, after the toner has gathered to some extent, the toner can no longer stay in the blade prenip and falls sequentially by gravity (toner particles: TN3 in FIG. 6). And is temporarily deposited on the tip surface (cut surface) of the tip 64 of the cleaning blade 60 (indicated by TN4 in FIG. 6).
When a large amount of transfer residual toner accumulates in the blade pre-nip, the accumulated toner TN4 is pushed from the pre-nip side and slowly moves to the left in FIG. 6, and is opposite to the edge of the cleaning blade 60 (not shown). Is dropped by gravity, and once stored in the housing 30, it is discharged by the screw 74.

From the above phenomenon, it has been found that the abrasion of the photoreceptor is promoted by the aggregate of the external additive.
As a result of extensive studies to prevent the phenomenon of acceleration of wear of the photosensitive member by the aggregate of external additives, the dynamic fluidity of the toner is improved (that is, the FRI (difference value) or FRI (toner value) of the toner). It was found that when the ratio is within the above range, the generation of aggregates of external additives that wear the photoreceptor 16 is suppressed.
That is, as shown in FIG. 7, the flow (convection) indicated by the arrows Y2 and Y3 is generated in a dynamic state, and the external additive is not allowed to stay in the blade prenip as much as possible. It was kept from being reduced.

Here, what is important is not to retain the external additive in a dynamic state, and specifically, to create a state in which the external additive moves along the flow within a few seconds.
In order to confirm this phenomenon, a visualization environment using a high-speed camera was constructed, and detailed observations were made. For observation, a φ100 glass drum is manufactured, an ITO electrode (indium tin oxide electrode) that is a transparent electrode is formed on the surface, and the same specifications as the photoconductor used in the product are formed on the ITO electrode. A film in which a charge generation layer (CGL layer) and a charge transport layer (CTL layer) are coated was used as the photoreceptor 16. In addition, a charging device, a developing device, and a cleaning device having the same configuration as the product are arranged around the glass drum, and an observation device is prepared to perform an image forming process operation including these devices.

  As the high-speed camera, FASTCAM-ultima 1024 manufactured by Photoron was used, and a QM100 manufactured by Quester Co. was used as a long focus microscope on the sensor head. In addition, high-intensity lighting and a mirror were installed inside the glass drum so that it could be captured by a high-speed camera installed outside.

In this visualization environment, the type of toner was changed for observation. As a result, in the conventional toner, the aggregate of the external additive stays as shown in FIG. 6, and the toner with improved dynamic fluidity (FRI (difference value) or FRI (ratio) in the above range). ), It was confirmed that the external additive that was flowing as shown in FIG. 7 and stayed in a dynamic state was not observed.
In particular, when the tip 64 of the cleaning blade 60 is directed upward, the flow is disadvantageous due to the influence of gravity, and it has also been found that aggregates of external additives appear remarkably.

8 and 9 show an example of the result of observing the blade pre-nip from the back side of the glass drum in one frame of an image taken as a moving image.
In both cases, the tip 64 of the cleaning blade 60 is used in an upward direction. In FIGS. 8 and 9, 60 is a cleaning blade, TN2 is toner (toner particles) accumulated in the blade prenip, and TN3 is in the blade prenip. TN4 is toner (toner particles) deposited on the front end surface (cut surface) of the front end portion 64 of the cleaning blade 60.

  FIG. 8 is an observation result when a conventional toner is used, and G, which appears white in a band shape, is an aggregate of external additives staying in the blade prenip. As described above, when the glass drum is used and observed from the back side, it can be seen that the aggregate of the external additive can be clearly confirmed.

  On the other hand, FIG. 9 shows the observation results when using toner with improved dynamic fluidity (toner having FRI (difference value) or FRI (ratio) in the above range), with a band-like white deposit (in FIG. 8). The aggregate of the external additive indicated by G) is not observed, and it is understood that the aggregate of the external additive is not formed. However, although it is not visible due to the problem of resolution, the SEM analysis (scanning electron microscope) was conducted separately that the external additive pooled in the minute region of the blade prenip and the cleaning property was secured. (Observation analysis).

Next, a verification experiment using a toner having improved dynamic fluidity (a toner having an FRI (difference value) or FRI (ratio) in the above range) will be described.
In the experiment, “DCC450 (cleaning blade pressure 4 gf / mm (39.2 N / m))” manufactured by Fuji Xerox was used. The experiment environment was conducted in two environments of high temperature and high humidity (28 ° C, 85% RH) and low temperature and low humidity (10 ° C, 15% RH), and 2 x 2 obtained by multiplying the two conditions of the image area and the non-image area. The wear rate was evaluated with the matrix of and the average value was obtained. The total number of running cycles (total number of rotations of the photoconductor) is 50,000 Cycle. The results are shown in FIG.
In FIG. 10, the horizontal axis represents FRI (ratio), the vertical axis represents photoconductor wear rate (nm / kCycle [nm / photoconductor 1000 rotations]), and developers each containing 10 types of toner (details will be described later) are used. The measured measurement points are plotted. From this result, it can be seen that the photoreceptor wear rate increases almost in proportion to the FRI (ratio). The target value of 25 nm / kCycle indicates a photoconductor wear rate of about ½ of the conventional value. From this result, it was found that the target was achieved if the FRI (ratio) was 2.10 or less.

  On the other hand, FIG. 11 shows the result plotted similarly by FRI (difference value). It can be seen that FRI (difference value) shows a better correlation with the photoreceptor wear rate than FRI (ratio). From this result, it was found that if the FRI (difference value) is 220 mJ or less, the target of 25 nm / kCycle is achieved.

  In the evaluation experiment, the same results were obtained in both high temperature and high humidity (28 ° C., 85% RH) and low temperature and low humidity (10 ° C., 15% RH).

In addition, as a result of conducting a similar evaluation experiment by changing only the pressure of the cleaning blade in the range of 1.0 gf / mm to 10.0 gf / mm under the same configuration and conditions of the experimental apparatus, photoconductor wear Similar rates were obtained for FRI (ratio) and FRI (difference value), although the rates were different.
On the other hand, when the pressure applied to the cleaning blade was varied to less than 1.0 gf / mm, a result that cleaning failure was observed was obtained.
Further, when the pressing force of the cleaning blade was varied over 10.0 gf / mm, the result was that rotation failure occurred due to the increase in driving torque of the photosensitive member.

  In addition, as a result of performing a similar evaluation experiment by changing only the type of the photoconductor under the same configuration and conditions of the experimental apparatus, the FRI (ratio) and FRI (difference value) values are obtained although the photoconductor wear rates are different. A similar trend was obtained. As a result, it was also confirmed that the dynamic fluidity of the toner is dominant in reducing the wear of the photoreceptor and does not depend on the surface layer structure of the photoreceptor.

  Here, the developers each including 10 types of toners used in the verification experiment (developers 1 to 10 each including toners 1 to 10) are produced as follows.

[Toner 1]
(Preparation of polyester resin (A1) and polyester resin particle dispersion (a1))
In a heat-dried two-necked flask, 15 mol parts of polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (2,2) -2,2-bis (4 -Hydroxyphenyl) propane 85 mol part, terephthalic acid 10 mol part, fumaric acid 67 mol part, n-dodecenyl succinic acid 3 mol part, trimellitic acid 20 mol part, and these acid components (terephthalic acid, n After adding 0.05 mol part of dibutyltin oxide to the total number of moles of dodecenyl succinic acid, trimellitic acid and fumaric acid), introducing nitrogen gas into the container and maintaining the inert atmosphere to raise the temperature The copolycondensation reaction was carried out at 150 to 230 ° C. for 12 to 20 hours. Thereafter, the pressure was gradually reduced at 210 ° C. to 250 ° C. to synthesize a polyester resin (A1). This resin had a weight average molecular weight Mw of 65000 and a glass transition temperature Tg of 65 ° C.

  In an emulsification tank of a high-temperature / high-pressure emulsification apparatus (Cabitron CD1010, slit: 0.4 mm), 3000 parts by mass of the obtained polyester resin, 10000 parts by mass of ion-exchanged water, and 90 parts by mass of a surfactant sodium dodecylbenzenesulfonate were added. Then, after heating and melting at 130 ° C., it was dispersed at 110 ° C. at a flow rate of 3 L / m at 10,000 rpm for 30 minutes, passed through a cooling tank, and then passed through an amorphous resin particle dispersion (high temperature / high pressure emulsifier (Cabitron CD1010 .4 mm) was recovered to obtain a polyester resin particle dispersion (a1).

(Preparation of polyester resin (B1) and polyester resin particle dispersion (b1))
Into a heat-dried three-necked flask, 45 mol parts of 1,9-nonanediol, 55 mol parts of dodecanedicarboxylic acid and 0.05 mol parts of dibutyltin oxide as a catalyst were added, and the air in the container was then decompressed. Was placed in an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 2 hours with mechanical stirring. Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 5 hours, air-cooled when it became a viscous state, the reaction was stopped, and the polyester resin (B1) was synthesize | combined. This resin had a weight average molecular weight Mw of 25000 and a melting temperature Tm of 73 ° C.
Thereafter, a polyester resin dispersion (b1) was obtained using a high-temperature and high-pressure emulsification apparatus (Cabitron CD1010, slit: 0.4 mm) under the same conditions as those for preparing the polyester resin dispersion (A1).

(Preparation of colorant particle dispersion)
-Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 1000 parts by mass-Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku) Anionic surfactant (sodium lauryl sulfate Wako Jun (Made by Yakuhin Co., Ltd.): 150 parts by mass, ion-exchanged water: 4000 parts by mass The above are mixed, dissolved, and dispersed and colored for 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006). A colorant particle dispersion was prepared by dispersing agent (cyan pigment) particles. The volume average particle diameter of the colorant (cyan pigment) particles in the colorant particle dispersion was 0.15 μm, and the colorant particle concentration was 20%.

(Preparation of release agent particle dispersion)
・ Wax (WEP-2, manufactured by NOF Corporation): 100 parts by mass
Anionic surfactant Neogen SC (Daiichi Kogyo Seiyaku): 2 parts by mass
-Ion exchange water: 300 parts by mass-Fatty acid amide wax (Nippon Seikatsu, Neutron D: 100 parts by mass)-Anionic surfactant (manufactured by Nippon Oil & Fats, Newlex R): 2 parts by mass-Ion exchange water: 300 parts by mass Part The above components were heated to 95 ° C. and dispersed using a homogenizer (manufactured by IKA, Ultra Tarrax T50), and then dispersed with a pressure discharge type gorin homogenizer (Gorin), and the volume average particle size was 200 nm. A release agent particle dispersion (1) (release agent concentration: 20% by mass) obtained by dispersing release agent particles as described above was prepared.

(Preparation of toner particles 1)
Polyester resin particle dispersion (a1): 340 parts by mass Polyester resin particle dispersion (b1): 160 parts by weight Colorant particle dispersion: 50 parts by weight Release agent particle dispersion: 60 parts by weight Surface activity Aqueous solution: 10 parts by mass, 0.3 M nitric acid aqueous solution: 50 parts by mass, ion-exchanged water: 500 parts by mass

The above components were placed in a round stainless steel flask and dispersed using a homogenizer (IKA, Ultra Tarrax T50), then heated to 42 ° C. in a heating oil bath and held for 30 minutes. The temperature of the heating oil bath was raised and maintained at 58 ° C. for 30 minutes, and at the stage where it was confirmed that aggregated particles were formed, after adding 100 parts by mass of additional polyester resin particle dispersion (a1), further Hold for 30 minutes.
Subsequently, nitrilotriacetic acid Na salt (manufactured by Chubu Kirest Co., Ltd., Kirest 70) was added so as to be 3% of the total liquid. Thereafter, a 1N aqueous sodium hydroxide solution was gently added until pH 7.2 was reached, and then the mixture was heated to 85 ° C. while continuing stirring and maintained for 3.0 hours. Thereafter, the reaction product was filtered, washed with ion-exchanged water, and then dried using a vacuum dryer to obtain toner particles 1.

  When the particle diameter at this time was measured with a Coulter Multisizer, the volume average particle diameter D50 was 4.5 μm, and the particle size distribution coefficient GSD was 1.22.

(Preparation of Toner 1)
Toner particles 1: 100 parts by mass, 0.9 parts by mass of silica particles (volume average particle size: 50 nm), 0.6 parts by mass of titania particles (volume average particle size: 40 nm), and fluororesin particles (PTFE particles: (Volume average particle size: 3 μm) and 0.3 part by mass, and after blending for 15 minutes at a peripheral speed of 30 m / s using a 5 liter Henschel mixer, coarse particles using a sieve with an opening of 45 μm Then, Toner 1 was produced.

(Toner 2 to 10)
According to Table 1, toners 2 to 10 were prepared in the same manner as toner 1 except that the types and amounts of external additives for the toner particles were changed. Table 1 shows the FRI (difference value) and FRI (ratio) of each toner.

Developers 1 to 10 were respectively prepared by mixing the obtained toner and the following resin-coated ferrite carrier so that the toner concentration was 7% by weight.
-Resin coated ferrite carrier-
100 parts by mass of ferrite particles (manufactured by Powder Tech Co., Ltd., average particle size 50 μm) and 1.5 parts by mass of methyl methacrylate resin (manufactured by Mitsubishi Rayon Co., Ltd., molecular weight 95,000, component ratio of 10,000 or less) are combined with 500 parts by mass of toluene. Put in a pressure kneader and stir and mix at room temperature for 15 minutes, then heat up to 70 ° C. while mixing under reduced pressure to distill off toluene, then cool and classify using a 105 μm sieve to obtain a resin-coated ferrite carrier. Obtained.

The toner to which fluororesin particles (PTFE particles) were added as a lubricant had small values for FRI (ratio) and FRI (difference value), and showed a tendency to reduce the wear rate. On the other hand, it was found that the toner to which no fluororesin particles were added had a high FRI (ratio) and FRI (difference value), and showed a tendency to have a high wear rate.
From the above demonstration experiment, it can be seen that the wear of the photosensitive member 16 is suppressed in this embodiment.

  In the present exemplary embodiment, an image forming apparatus including an intermediate transfer apparatus including a primary transfer roll 26, an intermediate transfer belt 24, a secondary transfer roll 36, and the like as a transfer apparatus and a tandem image forming apparatus have been described. However, the present invention is not limited to this. For example, a direct transfer type image forming apparatus that directly transfers a toner image formed on the photoconductor 16 to the recording paper P, or an image formation that forms a monochrome image including the single photoconductor 16. A known image forming apparatus such as an apparatus may be applied.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming means 14 Image forming unit 16 Photosensitive body (an example of an image holding body)
18 Charging device 20 Exposure device (an example of electrostatic latent image forming means)
22 Developing Device 24 Intermediate Transfer Belt 26 Primary Transfer Roll 27 Photosensitive Unit 28 Cleaning Device 30 Housing 32 Drive Roll 33 Driven Roll 34 Back Roll 36 Secondary Transfer Roll 40 Fixing Device 42 Transport Mechanism 44 Paper Feed Unit 46 Pickup Roll 48 Transport Roll 50 Guide member 50 Cleaning blade 52, 54 Guide roll 56 Conveying belt 58 Paper discharge roll 60 Cleaning blade 64 Cleaning blade tip 65 Cleaning blade edge 72 Seal member 74 Screw 76 Sheet metal 78 Screw P Recording paper (on recording medium) One case)

Claims (10)

An image carrier,
A charging device for charging the surface of the image carrier;
An electrostatic latent image forming device that forms an electrostatic latent image on the surface of the image carrier charged by the charging device;
FRI (flow velocity index) [(measured value when the rotational speed of the rotary blade is 10 mm / s) / (measured value when the rotational speed of the rotary blade is 100 mm / s)] measured by the powder rheometer is 1. 70 to 2.10 and the difference value of the total energy value measured in the flow rate change test of the powder rheometer [(measured value when the rotational speed of the rotary blade is 10 mm / s) − (rotational speed of the rotary blade] Is measured at 100 mm / s)] is stored in a developer containing toner having a value of 187 mJ or more and 220 mJ or less, and the electrostatic latent image formed by the electrostatic latent image forming apparatus is developed with the developer. A developing device,
A transfer device for transferring the image developed by the developing device and held on the surface of the image carrier to a recording medium;
A cleaning device that removes the toner remaining on the surface of the image carrier, and includes a cleaning blade that is disposed at a pressure applied to the surface of the image carrier of 1.0 gf / mm to 10.0 gf / mm. A cleaning device;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the toner includes toner particles and silica particles, titania particles, and fluororesin particles as external additives that are externally added to the toner particles. The image forming apparatus according to claim 1, wherein the toner includes toner particles and a flow accelerator externally added to the toner particles. The image forming apparatus according to claim 3 , wherein the flow accelerator is a fluororesin particle. The fluorine outer added amount of the resin particles, the image forming apparatus according to claim 2 or claim 4 1.50 mass% or less than 0.05 wt% with respect to the toner particles. A charging step for charging the surface of the image carrier;
An electrostatic latent image forming step of forming an electrostatic latent image on the surface of the image carrier charged by the charging step;
FRI (flow velocity index) [(measured value when the rotational speed of the rotary blade is 10 mm / s) / (measured value when the rotational speed of the rotary blade is 100 mm / s)] measured by the powder rheometer is 1. 70 to 2.10 and the difference value of the total energy value measured in the flow rate change test of the powder rheometer [(measured value when the rotational speed of the rotary blade is 10 mm / s) − (rotational speed of the rotary blade] Development value for developing the electrostatic latent image formed in the electrostatic latent image forming step with a developer containing a toner having a measured value of 187 mJ or more and 220 mJ or less]
A transfer step of transferring the image developed in the development step and held on the surface of the image carrier to a recording medium;
A cleaning step of removing the toner remaining on the surface of the image carrier by a cleaning blade disposed at a pressure applied to the surface of the image carrier of 1.0 gf / mm to 10.0 gf / mm;
An image forming method comprising: The image forming method according to claim 6 , wherein the toner includes toner particles and silica particles, titania particles, and fluororesin particles as external additives added to the toner particles. The image forming method according to claim 6 , wherein the toner includes toner particles and a flow accelerator externally added to the toner particles. The image forming method according to claim 8 , wherein the glidant is fluororesin particles. The image forming method according to claim 7 or 9 , wherein an external addition amount of the fluororesin particles is 0.05% by mass or more and 1.50% by mass or less with respect to the toner particles.