JP2020086195A - Process cartridge and image formation device - Google Patents

Abstract

To provide a process cartridge which is low in photoreceptor drive torque without image issues due to contaminated charging member, and an image formation device.SOLUTION: A process cartridge 7 has: a developing unit 3 including a developing roller 4 and the like; and a photoreceptor unit 13 including a photoreceptor drum 1 and the like. The developing unit 3 is composed of a developing chamber 17 and a developer storage chamber 18, and the developer storage chamber 18 stores therein toner 10 as developer. The toner 10 has Martens hardness of 200-1100 MPa at maximum load 2.0x10-4 N, and contains organic silicon polymer in a surface layer. The organic silicon polymer has a fastening ratio of 90% or more with respect to the toner 10. A charging roller 2 and a cleaning blade 8 as a cleaning member are disposed on the photoreceptor unit 13. A contact part of the cleaning blade 8 with the photoreceptor drum 1 has dynamic hardness of 0.07-1.1 mN/μm2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a process cartridge and an image forming apparatus mounted on an electrophotographic or electrostatic recording type image forming apparatus.

An electrophotographic image forming apparatus forms an image of toner, which is a developer, on a photosensitive drum, which is an image carrier, from a developing device, transfers the toner from the photosensitive drum to a recording material, and sequentially fixes the toner. To get the image. In a color image forming apparatus, an image forming apparatus of an intermediate transfer belt system, which transfers a toner image from a photosensitive drum to an intermediate transfer belt and then transfers the toner image again from the intermediate transfer belt to a recording material, has been put into practical use.

In the transfer process from the photoconductor drum to the intermediate transfer belt, toner charged to the opposite polarity to normal or toner with a low charge amount may remain on the photoconductor drum without being transferred in the transfer process. A cleaning device is used in contact with the photosensitive drum.

The developing device, the photosensitive drum, and the cleaning device may be integrally configured as a process cartridge that can be attached to and detached from the image forming apparatus.

As a cleaning device, a counter-type blade cleaning in which a cleaning blade made of an elastic body is contacted in a counter direction is widely used from the viewpoint of the simple structure and the removal ability.

In the counter type blade cleaning, the cleaning blade is strongly brought into contact with and rubbed against the photosensitive drum. Therefore, the drive torque of the photosensitive drum occupies most of the process cartridge drive torque.

To reduce power consumption by reducing the drive torque of the image forming apparatus in which the process cartridge is mounted and to reduce the size of the image forming apparatus and the apparatus, there are the following that reduce the torque in blade cleaning.

In Patent Document 1, there is a toner in which spherical silica and non-spherical silica are externally added to a toner, and a lubricant such as a fatty acid metal salt is applied to a photosensitive drum. Here, in the low temperature and low humidity environment, low torque is achieved by the effect of the lubricant. Also, in a high temperature and high humidity environment, discharge products adhere to the lubricant, resulting in high torque, so torque is reduced by interposing a spherical silica external additive between the cleaning blade and the photoconductor (hereinafter referred to as the contact part). is doing.

In Patent Document 2, the liberation rate of the external additive contained in the toner is 1% or more, and the external additive is supplied to the cleaning member, and the torque is lowered by interposing it in the contact portion as in Document 1. ing.

JP, 2005-22078, A JP, 2003-280255, A

However, the above-mentioned prior art has the following problems. In Patent Documents 1 and 2, a low torque is realized by interposing an external additive in the contact portion. For this reason, it means that the external additive is gradually discharged to the downstream side of the cleaning blade, and during long-term use, contamination of the charging member causes streak-like density change on the image, and unevenness in the image. May occur.

Further, in Patent Document 1, a fatty acid metal salt is used as a lubricant in order to achieve low torque. The fatty acid metal salt forms a film on the photoconductor drum to reduce the torque. However, if the film of the fatty acid metal salt is not properly maintained, the torque may rather increase. For this reason, it is necessary to precisely control the contact pressure of the cleaning blade or to provide a leveling member, and the addition of members complicates the structure of the image forming apparatus and the supply and leveling control of the fatty acid metal salt. ..

An object of the present invention is to provide a process cartridge having a low photosensitive member driving torque without causing a problem of an image due to contamination of a charging member.

An object of the present invention is to solve the above problems, and to reduce the driving torque of a process cartridge mounted in an image forming apparatus and prevent contamination of a charging member.
A developer, a developing device, an image carrier for carrying a developer image formed by developing the electrostatic latent image by the developer, a charging member, and a contact portion for contacting the image carrier, A process cartridge having a cleaning member for cleaning the surface of the image carrier by a contact portion,
The developer in the surface layer _{R0-SiO 3/2} (R0 carbon 6 alkyl group) include organosilicon polymer represented by,
The fixing rate of the organosilicon polymer to the developer is 90% or more,
The Martens hardness when measured under the condition of the maximum load of 2.0×10 −4 N is 200 MPa or more and 1100 MPa or less,
The dynamic hardness of the contact portion of the cleaning member with the image carrier is DHs, and the dynamic hardness is
0.07 (mN/μm2)≦DHs≦1.1 (mN/μm2)
Is characterized in that

According to the present invention, it is difficult to deform in the cleaning portion, and the toner having a high sticking ratio of the surface layer is sufficiently pressed and held by the cleaning blade having a high surface hardness, so that there is no problem of the image due to the contamination of the charging member. It is possible to provide an image forming apparatus having a low photosensitive member drive torque.

FIG. 1 is a diagram showing an entire image forming apparatus according to the present invention. It is a figure showing the process cartridge concerning this invention. It is a figure showing the outline of the cleaning blade concerning the present invention. FIG. 6 is a diagram showing the definition of the contact state of the cleaning blade with the photosensitive drum in the present invention. FIG. 6 is a diagram illustrating a toner interposition state in a cleaning blade contact portion according to the mechanism of the present invention.

Hereinafter, an embodiment of a process cartridge in which the driving torque of the image carrier is reduced and the charging member is prevented from being contaminated will be described in more detail with reference to the drawings.

(Image forming device)
The overall configuration of one embodiment of the electrophotographic image forming apparatus will be described. FIG. 1 is a sectional view of an image forming apparatus 100 according to this embodiment. The image forming apparatus 100 according to the present embodiment is a full-color laser beam printer that employs a tandem system and an intermediate transfer system. The image forming apparatus 100 can form a full-color image on a recording material (for example, recording paper, plastic sheet, cloth, etc.) according to the image information. The image information is input to the image forming apparatus main body from an image reading apparatus connected to the image forming apparatus main body or a host device such as a personal computer communicably connected to the image forming apparatus main body. In the image forming apparatus 100, the process cartridges 7 as a plurality of image forming units form SY and SM for forming images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. , SC, SK. In the present embodiment, the image forming units SY, SM, SC, SK are arranged in a line in a direction intersecting the vertical direction.

The process cartridge 7 is attachable/detachable to/from the image forming apparatus 100 via a mounting guide such as a mounting guide and a positioning member provided in the main body of the image forming apparatus. In the present embodiment, the process cartridges 7 for each color have the same shape, and the process cartridges 7 for each color have yellow (Y), magenta (M), cyan (C), and black ( The toner (developer) of each color of K) is stored. Although the process cartridge is described in the present embodiment, the developing device 3 may be configured to be independently attachable to and detachable from the image forming apparatus main body.

The photosensitive drum 1 as an image carrier that carries an electrostatic image (electrostatic latent image) is rotationally driven by a driving unit (driving source) not shown. A scanner unit (exposure device) 30 is arranged around the photosensitive drum 1. The scanner unit 30 is an exposure unit that irradiates a laser based on image information to form an electrostatic image (electrostatic image) on the photosensitive drum 1. An intermediate transfer belt 31 as an intermediate transfer member for transferring the toner image on the photosensitive drums 1 to the recording material 12 is arranged facing the four photosensitive drums 1.

The intermediate transfer belt 31 formed of an endless belt as an intermediate transfer member contacts all the photoconductor drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) in the drawing.

On the inner peripheral surface side of the intermediate transfer belt 31, four primary transfer rollers 32 as primary transfer means are arranged in parallel so as to face each photoconductor drum 1. Then, a voltage having a polarity opposite to the regular charging polarity of the toner is applied to the primary transfer roller 32 from a primary transfer bias power source (high voltage power source) as a primary transfer bias applying unit (not shown). As a result, the toner image on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 31.

Further, a secondary transfer roller 33 as a secondary transfer means is arranged on the outer peripheral surface side of the intermediate transfer belt 31. Then, a voltage having a polarity opposite to the regular charging polarity of the toner is applied to the secondary transfer roller 33 from a secondary transfer bias power source (high voltage power source) as a secondary transfer bias applying unit (not shown). As a result, the toner image on the intermediate transfer belt 31 is transferred (secondarily transferred) to the recording material 12. For example, when forming a full-color image, the above-described process is sequentially performed in the image forming units SY, SM, SC, and SK, and the toner images of the respective colors are sequentially superposed and primarily transferred onto the intermediate transfer belt 31. Then, the recording material 12 is conveyed to the secondary transfer portion in synchronization with the movement of the intermediate transfer belt 31. Then, the four-color toner images on the intermediate transfer belt 31 are collectively secondarily transferred onto the recording material 12 by the action of the secondary transfer roller 33 that is in contact with the intermediate transfer belt 31 via the recording material 12. It

The recording material 12 to which the toner image is transferred is conveyed to a fixing device 34 as a fixing unit. By applying heat and pressure to the recording material 12 in the fixing device 34, the toner image is fixed on the recording material 12.

(Process cartridge)
The overall structure of the process cartridge 7 installed in the image forming apparatus of this embodiment will be described.

FIG. 2 is a cross-sectional (main cross-sectional) view of the process cartridge 7 according to the present embodiment as viewed along the longitudinal direction (rotational axis direction) of the photosensitive drum 1. In this embodiment, the configuration and operation of the process cartridge 7 for each color are substantially the same except for the type (color) of the contained developer. Each operation in this embodiment is controlled by a control unit (control means) of a CPU (not shown).

The process cartridge 7 includes a developing unit 3 including the developing roller 4 and the like, and a photoconductor unit 13 including the photoconductor drum 1 and the like.

The developing unit 3 includes a developing chamber 17 and a developer containing chamber 18, and the developer containing chamber 18 is arranged below the developing chamber 17. The toner 10 as a developer is stored in the developer storage chamber 18. In this embodiment, the normal charging polarity of the toner 10 is negative. Here, the regular charging polarity is the charging polarity for developing the electrostatic image. In this embodiment, since the negative electrostatic image is reversely developed, the normal charging polarity of the toner is negative. However, the present invention is not limited to the negatively chargeable toner.

Further, the developer accommodating chamber 18 is provided with a toner conveying member 22 for conveying the toner 10 to the developing chamber 17, and the toner is conveyed to the developing chamber 17 by rotating in the direction of arrow G in the figure. Transporting.

The developing chamber 17 is provided with a developing roller 4 as a developer carrying member that comes into contact with the photosensitive drum 1 and rotates in a direction indicated by an arrow D. In the present embodiment, the developing roller 4 and the photoconductor drum 1 rotate so that their surfaces move in the same direction at the facing portions. A voltage sufficient for developing and visualizing the electrostatic image on the photosensitive drum 1 as a toner image is applied to the developing roller 4 from a first power source (high voltage power source) (not shown) as first voltage applying means. Is applied.

Further, inside the developing chamber 17, a toner supply roller (hereinafter, simply referred to as “supply roller”) 5 as a developer supply member for supplying the toner conveyed from the toner storage chamber 18 to the developing roller 4, and supply. A developer amount regulating member (hereinafter, simply referred to as “regulating member”) 6 that regulates the amount of toner coated on the developing roller 4 supplied by the roller 5 and imparts electric charge is arranged.

The supply roller 5 is an elastic sponge roller having a conductive cored bar and a foam layer on the surface, and is arranged so as to form a contact portion with the developing roller 4, and is rotated in the direction of arrow E in the figure. To do. However, the rotation direction of the supply roller may be opposite to E.

Further, a voltage is applied to the supply roller 5 from a second power source (high voltage power source) (not shown) as a second voltage applying means.

The toner supplied to the developing roller 4 by the supply roller 5 enters the contact portion between the regulation member 8 and the developing roller 4 by the rotation of the developing roller 4 in the arrow D direction. The toner is triboelectrically charged by the sliding friction between the developing roller 4 and the regulating member 8 and is given an electric charge, and at the same time, its layer thickness is regulated. The regulated toner on the developing roller 4 is conveyed to a portion facing the photoconductor drum 1 by the rotation of the developing roller 4, and the electrostatic image on the photoconductor drum 1 is developed and visualized as a toner image.

On the other hand, the photoconductor drum 1 is rotatably attached to the photoconductor unit 13 via a bearing (not shown). The photoconductor drum 1 is an organic photoconductor drum and has an outer diameter of 24 mm. By receiving the driving force of a driving motor P (not shown) as a drum driving means, the drum is driven to rotate in the direction of arrow A.

Further, in the photoconductor unit 13, the charging roller 2 and the cleaning member 8 are arranged so as to contact the peripheral surface of the photoconductor drum 1. The charging roller 2 is biased to the photosensitive drum by a spring (not shown), and is driven to rotate as the photosensitive drum rotates.

The cleaning blade rubs the photosensitive drum 1 at a relative speed equal to the surface speed of the photosensitive drum 1 by the rotation of the photosensitive drum 1, scrapes off the toner remaining in the transfer process, and prevents the charging member from being contaminated. In addition, in the charging step, the discharge products attached to the surface of the photosensitive drum 1 are removed to prevent the friction of the photosensitive drum 1 from increasing.

The scraped toner is stored in the collection chamber 9. The toner may be stored in a toner recovery container provided in the image forming apparatus via the recovery chamber 9.

Hereinafter, details of the toner and the cleaning blade according to the present invention will be described.

(toner)
A toner having a Martens hardness of 200 to 1100 MPa at the maximum load of 2×10 −4 N can be obtained by forming an organic silicon polymer on the surface layer. Further, a method of forming an organic silicon polymer on the surface layer is also suitable for achieving a fixing rate of 90% or more. The details will be described below.

<Method of measuring toner hardness>
Hardness is one of the mechanical properties on or near the surface of an object, and is the degree of difficulty in deforming or scratching an object when it is about to be deformed or scratched by foreign matter. There are various measurement methods and definitions. For example, the measuring method is used properly depending on the size of the measuring area. In the case where the measuring area is 10 μm or more, the Vickers method is used. .. As a definition, for example, Brinell hardness or Vickers hardness is used as indentation hardness, Martens hardness is used as scratch hardness, and Shore hardness is used as repulsion hardness.

In the toner measurement, the nano-indentation method is preferably used since the general particle size is 3 μm to 10 μm. According to the studies by the inventors, the Martens hardness, which represents the scratch hardness, is suitable as the regulation of the hardness for expressing the effect of the present invention. This is because the scratch hardness can represent the strength of the toner against scratching by a hard substance such as a metal or an external additive in the developing machine.

The method for measuring the Martens hardness of the toner by the nanoindentation method is calculated from the obtained load-displacement curve in a commercially available device conforming to ISO14577-1 according to the procedure of the indentation test specified in ISO14577-1. be able to. In the present invention, an ultra-fine indentation hardness tester “ENT-1100b” (manufactured by Elionix Co., Ltd.) was used as a device conforming to the ISO standard. The measuring method is described in the "ENT1100 operation manual" attached to the apparatus, and the specific measuring method is as follows.

Regarding the measurement environment, the inside of the shield case was kept at 30.0° C. by the attached temperature control device. Keeping the ambient temperature constant is effective in reducing variations in measured data due to thermal expansion and drift. The set temperature was set to 30.0° C. assuming the temperature in the vicinity of the developing device where the toner rubs. The standard sample table attached to the device was used as the sample table. After the toner was applied, weak air was blown so that the toner was dispersed, and the sample table was set in the device and held for 1 hour or more before measurement. ..

For the indenter, a flat indenter (titanium indenter, the tip of which is made of diamond) having a 20 μm square plane attached to the device was used as the indenter. For a small-diameter and spherical object such as toner, an object to which an external additive is attached, or an object having unevenness on the surface, a flat indenter is used because a sharp indenter greatly affects the measurement accuracy. The maximum load of the test is set to 2.0×10 ⁻⁴ N. By setting this test load, the hardness can be measured without destroying the surface layer of the toner under the condition corresponding to the stress applied to one toner particle in the developing section. In the present invention, since abrasion resistance is important, it is important to measure hardness while maintaining the surface layer without breaking it.

As the particles to be measured, those in which the toner alone is present on the measurement screen (field size: width 160 μm, height 120 μm) by the microscope attached to the apparatus are selected. However, in order to eliminate the error of the displacement amount as much as possible, the particle diameter (D) is selected within a range of ±0.5 μm of the number average particle diameter (D1) (D1-0.5 μm≦D≦D1+0.5 μm). .. The particle diameter of the particles to be measured was measured by measuring the major axis and the minor axis of the toner using software attached to the apparatus, and [(major axis+minor axis)/2] was defined as the particle diameter D (μm). Further, the number average particle diameter is measured by a method described later using "Coulter Counter Multisizer 3 (manufactured by Beckman Coulter, Inc.)".

At the time of measurement, 100 particles of any toner having a particle diameter D (μm) satisfying the above conditions are selected and measured. The conditions to be input at the time of measurement are as follows.
Test mode: Load-unload test Test load: 20.000 mgf (=2.0×10 ⁻⁴ N)
Number of divisions: 1000step
Step interval: 10 msec
When the analysis menu “Data analysis (ISO)” is selected and measurement is performed, the Martens hardness is analyzed and output by the software attached to the apparatus after the measurement. The above measurement was performed on 100 toner particles, and the arithmetic mean value thereof was defined as the Martens hardness in the present invention.

By adjusting the Martens hardness when measured under the condition of the maximum load of the toner of 2.0×10 ⁻⁴ N to 200 MPa or more and 1100 MPa or less, it is possible to reduce the deformation of the toner in the cleaning nip as compared with the conventional toner. became. That is, the contact area between the cleaning blade and the photosensitive drum can be kept small and the torque can be reduced.

If the Martens hardness is lower than 200 MPa, the effect of the present invention cannot be satisfactorily obtained.

On the other hand, if the Martens hardness is higher than 1100 MPa, it may cause damage to the photosensitive drum or the developing member in some cases, so it is necessary to be careful.

The means for adjusting the Martens hardness at the time of measurement under the maximum load of 2.0×10 ⁻⁴ N to 200 MPa or more and 1100 MPa or less is not particularly limited. However, since the hardness is significantly higher than the hardness of the organic resin used for a general toner, it is difficult to achieve it by a means that is usually used to increase the hardness. For example, it is difficult to achieve it by means of designing a resin having a high glass transition temperature, increasing the molecular weight of resin, thermosetting, adding a filler to the surface layer, or the like.

The Martens hardness of the organic resin used for a general toner is about 50 MPa to 80 MPa when measured under the condition of the maximum load of 2.0×10 ⁻⁴ N. Further, even when the hardness is increased by designing the resin or increasing the molecular weight, it is about 120 MPa or less. Furthermore, even when a filler such as a magnetic material or silica is filled in the vicinity of the surface layer and cured by heat, it is about 180 MPa or less, and the toner of the present invention is significantly harder than general toner.

<Hardness control method>
As one means for adjusting the specific hardness range, for example, the surface layer of the toner is formed of a substance such as an inorganic material having an appropriate hardness, and the chemical structure or macro structure is controlled to have an appropriate hardness. There is a method of doing.

As a specific example, the substance that can have the above-mentioned specific hardness includes an organic silicon polymer, and the selection of the material includes the number of carbon atoms directly bonded to the silicon atom of the organic silicon polymer and the carbon chain length. The hardness can be adjusted by. The toner particles have a surface layer containing an organosilicon polymer, and the number of carbon atoms directly bonded to silicon atoms of the organosilicon polymer is 1 or more and 3 or less (preferably 1 or more and 2 or less). , And more preferably 1), since it is easy to adjust to the above specific hardness.

As a means for adjusting the Martens hardness by the chemical structure, it is possible to adjust the chemical structure such as crosslinking of the surface layer substance or the degree of polymerization. As means for adjusting the Martens hardness by the macro structure, it is possible to adjust the uneven shape of the surface layer or the network structure for connecting the projections. When the organosilicon polymer is used as the surface layer, these adjustments can be made by adjusting the pH, concentration, temperature, time, etc. when pretreating the organosilicon polymer. Further, it can be adjusted by the timing, form, concentration, reaction temperature and the like of applying the surface layer of the organosilicon polymer to the core particles of the toner.

The following method is particularly preferred in the present invention. First, core particles of a toner containing a binder resin and a colorant are manufactured and dispersed in an aqueous medium to obtain a core particle dispersion liquid. The concentration at this time is preferably such that the solid content of the core particles is 10% by mass or more and 40% by mass or less based on the total amount of the core particle dispersion liquid. The temperature of the core particle dispersion is preferably adjusted to 35°C or higher. Further, the pH of the core particle dispersion liquid is preferably adjusted to a pH at which condensation of the organosilicon compound is difficult to proceed. Since the pH at which condensation of the organosilicon polymer is difficult to proceed differs depending on the substance, it is preferably within ±0.5 around the pH at which the reaction is most difficult to proceed.

On the other hand, it is preferable to use a hydrolyzed organosilicon compound. For example, the organosilicon compound is hydrolyzed in a separate container as a pretreatment. When the amount of the organosilicon compound is 100 parts by mass, the charged concentration of hydrolysis is preferably 40 parts by mass or more and 500 parts by mass or less of water obtained by removing ion components such as ion-exchanged water and RO water, and more preferably 100 parts by mass of water. It is above 400 parts by mass. As conditions for hydrolysis, the pH is preferably 2 to 7, the temperature is 15 to 80° C., and the time is 30 to 600 minutes.

By mixing the obtained hydrolyzed liquid and the core particle dispersion liquid and adjusting the pH (preferably 6 to 12, or 1 to 3, and more preferably 8 to 12) suitable for condensation, the organosilicon compound is removed. A surface layer can be applied to the surface of the core particles of the toner while being condensed. Condensation and surface coating are preferably performed at 35° C. or higher for 60 minutes or longer. Further, the surface macrostructure can be adjusted by adjusting the time of holding at 35° C. or higher before adjusting the pH suitable for condensation, but if the time is too long, the toner of Martens hardness of the present invention can be obtained. Since it is difficult, 3 minutes or more and 120 minutes or less are preferable.

By the means as described above, it is possible to reduce the reaction residues, form irregularities on the surface layer, and further form a network structure between the protrusions, so that it is easy to obtain a toner having the above specific Martens hardness. ..

When the surface layer containing the organosilicon polymer is used, the fixing rate of the organosilicon polymer is preferably 90% or more and 100% or less. More preferably, it is 95% or more. The method for measuring the sticking rate of the organosilicon polymer will be described later.

<Regarding Surface Layer Containing Organosilicon Polymer>
When the toner particles have a surface layer containing an organic silicon polymer, it preferably has a partial structure represented by the formula (1).

R-SiO _3/2 formula (1)
(R represents a hydrocarbon group having 1 to 6 carbon atoms.)
In the organosilicon polymer having the structure of formula (1), one of the four valences of Si atoms is bonded to R and the remaining three are bonded to O atoms. Each of the O atoms has a valence of 2 and is bonded to Si, that is, a siloxane bond (Si-O-Si). Considering Si atoms and O atoms as the organosilicon polymer, two Si atoms have three O atoms, and thus they are expressed as —SiO _3/2 . It is considered that the -SiO _3/2 structure of this organosilicon polymer has properties similar to silica (SiO ₂ ) composed of many siloxane bonds. Therefore, it is considered that it is possible to increase the Martens hardness because it has a structure closer to that of an inorganic substance as compared with the toner formed by the surface layer of the conventional organic resin.

As a production example of the organosilicon polymer, the sol-gel method is preferable. The sol-gel method is a method in which a liquid raw material is used as a starting raw material to undergo hydrolysis and condensation polymerization to gel through a sol state, and is used for synthesizing glass, ceramics, organic-inorganic hybrids, and nanocomposites. By using this manufacturing method, it is possible to manufacture functional materials having various shapes such as surface layers, fibers, bulk bodies, and fine particles from a liquid phase at a low temperature.

Specifically, the organosilicon polymer present in the surface layer of the toner particles is preferably produced by hydrolysis and polycondensation of a silicon compound represented by alkoxysilane.

By providing the toner particles with a surface layer containing the organosilicon polymer, environmental stability is improved, and it is possible to obtain a toner having excellent storage stability, which is unlikely to cause deterioration in toner performance during long-term use. ..

Furthermore, since the sol-gel method starts from a liquid and forms the material by gelling the liquid, various fine structures and shapes can be formed. In particular, when the toner particles are manufactured in an aqueous medium, the hydrophilicity of a hydrophilic group such as a silanol group of the organosilicon compound facilitates precipitation on the surface of the toner particles. The fine structure and shape can be adjusted by the reaction temperature, reaction time, reaction solvent, pH and the kind and amount of the organometallic compound.

The organosilicon polymer on the surface layer of the toner particles is preferably a polycondensation product of an organosilicon compound having a structure represented by the following formula (Z).

In formula (Z), R ₁ represents a hydrocarbon group having 1 to 6 carbon atoms, and R ₂ , R ₃ and R ₄ are each independently a halogen atom, a hydroxy group, an acetoxy group or an alkoxy. Represents a group.

The hydrocarbon group (preferably an alkyl group) of R ₁ can improve the hydrophobicity, and toner particles having excellent environmental stability can be obtained. Further, an aryl group which is an aromatic hydrocarbon group, for example, a phenyl group can be used as the hydrocarbon group. When R ₁ has a large hydrophobicity, the charge amount tends to increase in various environments. Therefore, in view of environmental stability, R ₁ is preferably a hydrocarbon group having 1 to 3 carbon atoms, It is more preferably a methyl group.

R ₂ , R ₃ and R ₄ are each independently a halogen atom, a hydroxy group, an acetoxy group or an alkoxy group (hereinafter, also referred to as a reactive group). These reactive groups are hydrolyzed, addition-polymerized and polycondensed to form a crosslinked structure, and a toner excellent in member contamination resistance and development durability can be obtained. Hydrolyzability is mild at room temperature, and an alkoxy group having 1 to 3 carbon atoms is preferable, and a methoxy group and an ethoxy group are more preferable, from the viewpoints of the depositability on the surface of the toner particles and the coatability. .. The hydrolysis, addition polymerization and condensation polymerization of R ₂ , R ₃ and R ₄ can be controlled by the reaction temperature, reaction time, reaction solvent and pH.

To obtain the organosilicon polymer used in the present invention, an organosilicon compound having _three reactive groups (R ₂ , R ₃ and R ₄ ) in one molecule excluding R ₁ in the above formula (Z) is used. (Hereinafter, also referred to as trifunctional silane) may be used alone or in combination of two or more.
Further, the content of the organosilicon polymer in the toner particles is preferably 0.5% by mass or more and 10.5% by mass or less.

When the content of the organosilicon polymer is 0.5% by mass or more, the surface free energy of the surface layer can be further reduced, the fluidity can be improved, and member contamination and fogging can be suppressed. .. When the content is 10.5% by mass or less, it is possible to make charge-up less likely to occur. The content of the organosilicon polymer should be controlled by the type and amount of the organosilicon compound used for forming the organosilicon polymer, the method for producing toner particles during the formation of the organosilicon polymer, the reaction temperature, the reaction time, the reaction solvent and the pH. You can

It is preferable that the surface layer containing the organosilicon polymer and the toner core particles are in contact with each other without any space. As a result, the occurrence of bleeding due to the resin component or the release agent inside the surface of the toner particles is suppressed, and a toner having excellent storage stability, environmental stability, and development durability can be obtained. In addition to the above organosilicon polymer, the surface layer may contain a resin such as a styrene-acrylic copolymer resin, a polyester resin or a urethane resin, and various additives.

<Method of manufacturing toner particles>
As a method for producing the toner particles, known means can be used, and a kneading and pulverizing method or a wet production method can be used. From the viewpoint of making the particle diameter uniform and controlling the shape, the wet manufacturing method can be preferably used. Further, as the wet production method, a suspension polymerization method, a dissolution suspension method, an emulsion polymerization aggregation method, an emulsion aggregation method and the like can be mentioned.

Here, the suspension polymerization method will be described. In the suspension polymerization method, first, a polymerizable monomer for producing a binder resin, a colorant and, if necessary, other additives are added using a ball mill or a disperser such as an ultrasonic disperser. A polymerizable monomer composition that is uniformly dissolved or dispersed is prepared (step of preparing the polymerizable monomer composition). At this time, if necessary, a polyfunctional monomer, a chain transfer agent, a wax as a release agent, a charge control agent, a plasticizer, etc. can be appropriately added.

Next, the polymerizable monomer composition is put into an aqueous medium prepared in advance, and a droplet made of the polymerizable monomer composition is desired by a stirrer or a disperser having a high shearing force. To the size of the toner particles (granulating step).

It is preferable that the aqueous medium in the granulation step contains a dispersion stabilizer in order to control the particle size of the toner particles, sharpen the particle size distribution, and suppress coalescence of the toner particles in the manufacturing process. The dispersion stabilizer is generally classified into a polymer that exhibits a repulsive force due to steric hindrance and a poorly water-soluble inorganic compound that stabilizes the dispersion by electrostatic repulsive force. Since the fine particles of the poorly water-soluble inorganic compound are dissolved by an acid or an alkali, they can be easily dissolved and removed by washing with an acid or an alkali after the polymerization, and thus are preferably used.

After the granulation step or while performing the granulation step, the temperature is preferably set to 50° C. or higher and 90° C. or lower to polymerize the polymerizable monomer contained in the polymerizable monomer composition to obtain a toner. A particle dispersion is obtained (polymerization step).

In the polymerization step, it is preferable to carry out a stirring operation so that the temperature distribution in the container becomes uniform. When the polymerization initiator is added, it can be carried out at an arbitrary timing and required time. Further, the temperature may be raised in the latter half of the polymerization reaction for the purpose of obtaining a desired molecular weight distribution, and further in the latter half of the reaction or the end of the reaction in order to remove unreacted polymerizable monomers, by-products and the like outside the system. After that, part of the aqueous medium may be distilled off by a distillation operation. The distillation operation can be performed under normal pressure or reduced pressure.

The particle diameter of the toner particles is preferably 3.0 μm or more and 10.0 μm or less in terms of obtaining a high-definition and high-resolution image. The weight average particle diameter of the toner can be measured by the pore electrical resistance method. For example, it can be measured by using "Coulter Counter Multisizer 3" (manufactured by Beckman Coulter, Inc.). The toner particle dispersion liquid thus obtained is sent to a filtration step for solid-liquid separating the toner particles and the aqueous medium.

Solid-liquid separation for obtaining toner particles from the obtained toner particle dispersion liquid can be carried out by a general filtration method, and thereafter, in order to remove foreign substances that could not be completely removed from the toner particle surface, reslurry or washing water is used. Further washing is preferably carried out by washing with water. After sufficient washing is performed, solid-liquid separation is performed again to obtain a toner cake. After that, it is dried by a known drying means, and if necessary, a group of particles having a particle diameter outside the predetermined range is separated by classification to obtain toner particles. The particles having a particle size outside the predetermined range may be reused in order to improve the final yield.

When forming a surface layer having an organosilicon polymer, when forming the toner particles in an aqueous medium, the hydrolysis solution of the organosilicon compound is added as described above while performing the polymerization step in the aqueous medium. The surface layer can be formed. Using the dispersion of toner particles after polymerization as the dispersion of core particles, a hydrolyzed liquid of an organosilicon compound may be added to form the surface layer. Further, in the case of other than an aqueous medium such as a kneading and pulverizing method, the obtained toner particles are dispersed in an aqueous medium and used as a core particle dispersion liquid, and as described above, the hydrolysis liquid of the organosilicon compound is added to the surface layer. Can be formed.

<Measurement Method of Securing Rate of Organosilicon Polymer>
160 g of sucrose (manufactured by Kishida Chemical Co., Ltd.) is added to 100 mL of ion-exchanged water and dissolved with a water bath to prepare a concentrated sucrose solution. In a centrifuge tube (volume 50 ml), 31 g of the above concentrated sucrose solution and 10 parts of a contaminone N (nonionic surfactant, anionic surfactant, organic builder, pH 7 precision measuring instrument washing neutral detergent) 6% of a mass% aqueous solution, manufactured by Wako Pure Chemical Industries, Ltd. is added to prepare a dispersion liquid. To this dispersion, 1.0 g of toner is added, and a lump of toner is loosened with a spatula or the like.

The centrifuge tube is shaken with a shaker at 350 spm (strokes per min) for 20 minutes. After shaking, the solution is replaced with a glass tube for swing rotor (capacity: 50 mL), and separated by a centrifuge (H-9R, manufactured by Kokusan Co., Ltd.) under conditions of 3500 rpm and 30 minutes. Visually confirm that the toner and the aqueous solution are sufficiently separated, and collect the toner separated in the uppermost layer with a spatula or the like. The collected aqueous solution containing the toner is filtered with a vacuum filter and then dried with a dryer for 1 hour or more. The dried product is disintegrated with a spatula and the amount of silicon is measured by fluorescent X-ray. The sticking ratio (%) is calculated from the ratio of the element amounts of the toner after washing and the initial toner to be measured.

The measurement of the fluorescent X-ray of each element conforms to JIS K 0119-1969, and specifically is as follows.

As the measuring device, a wavelength dispersive X-ray fluorescence analyzer "Axios" (manufactured by PANalytical) and attached dedicated software "SuperQ ver. 4.0F" (manufactured by PANalytical) for setting measurement conditions and analyzing measurement data. ) Is used. Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 10 mm, and the measurement time is 10 seconds. When measuring a light element, a proportional counter (PC) is used, and when measuring a heavy element, a scintillation counter (SC) is used.

As a measurement sample, about 1 g of the toner after washing and the initial toner was put into a dedicated aluminum ring for press with a diameter of 10 mm and flattened, and the tablet compression machine "BRE-32" (made by Maekawa Testing Machine Co., Ltd. ) Is used to press for 60 seconds at 20 MPa, and pellets molded to a thickness of about 2 mm are used.

The measurement is performed under the above conditions, the element is identified based on the obtained X-ray peak position, and the concentration is calculated from the count rate (unit: cps), which is the number of X-ray photons per unit time.

As a quantification method in the toner, for example, silica (SiO ₂ ) fine powder is added to 0.5 parts by mass with respect to 100 parts by mass of the toner particles, and sufficiently mixed using a coffee mill. To do. Similarly, fine silica powder is mixed with toner particles so as to be 2.0 parts by mass and 5.0 parts by mass, respectively, and these are used as a sample for a calibration curve.

For each sample, pellets of the sample for the calibration curve were prepared as described above using the tablet molding compressor, and when PET was used for the dispersive crystal, it was observed at the diffraction angle (2θ)=109.08°. The Si-Kα ray count rate (unit: cps) is measured. At this time, the acceleration voltage and the current value of the X-ray generator are set to 24 kV and 100 mA, respectively. A calibration curve of a linear function is obtained with the obtained X-ray count rate as the vertical axis and the addition amount of SiO ₂ in each calibration curve sample as the horizontal axis.

Next, the toner to be analyzed is pelletized as described above using a tablet molding compressor, and the count rate of the Si-Kα ray is measured. Then, the content of the organosilicon polymer in the toner is determined from the above calibration curve. The ratio of the elemental amount of the toner after washing with respect to the initial elemental amount of the toner calculated by the above method was determined and defined as the fixation rate (%).

[External additive]
The toner particles can be used as a toner without external addition, but in order to improve fluidity, charging property, cleaning property, etc., so-called external additives such as a fluidizing agent and a cleaning aid are added. It may be toner.

As the external additive, for example, inorganic oxide fine particles made of alumina fine particles, titanium oxide fine particles, etc., inorganic stearate compound fine particles such as aluminum stearate fine particles, zinc stearate fine particles, or strontium titanate, zinc titanate, etc. Inorganic titanate compound fine particles and the like. These can be used alone or in combination of two or more.

It is preferable that these inorganic fine particles are subjected to a gloss treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil or the like in order to improve heat resistant storage stability and environmental stability. The BET specific surface area of the external additive is preferably 10 m ² /g or more and 450 m ² /g or less.

The BET specific surface area can be determined by the low temperature gas adsorption method by the dynamic constant pressure method according to the BET method (preferably the BET multipoint method). For example, by using a specific surface area measuring device (trade name: Gemini 2375 Ver. 5.0, manufactured by Shimadzu Corporation), nitrogen gas is adsorbed on the surface of the sample, and measurement is performed using the BET multipoint method. The BET specific surface area (m ² /g) can be calculated.

The total amount of these various external additives added is preferably 0.05 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 3 parts by mass, relative to 100 parts by mass of the toner particles. It is below. Further, various external additives may be used in combination.

The toner preferably has positively charged particles on the surface of the toner particles. The number average particle diameter of the positively charged particles is preferably 0.10 μm or more and 1.00 μm or less. More preferably, it is 0.20 μm or more and 0.80 μm or less.

It has been revealed that the transfer efficiency is improved by using such positively charged particles through durable use. With the positively charged particles having the particle diameter, the toner particles can roll on the surface of the toner particles, friction between the photosensitive drum and the transfer belt promotes negative charging of the toner, and as a result, a positive charge is generated by applying the transfer bias. It is thought that this is due to suppression. The toner of the present invention is characterized by having a hard surface, and since positively charged particles are unlikely to stick or be buried in the surface of the toner particles, the transfer efficiency can be kept high.

The positively charged particles in the present invention are particles that are positively charged when mixed and stirred with a standard carrier (anionic: N-01) provided by the Japan Imaging Society to be triboelectrically charged.

The number average particle diameter of the external additive is measured using a scanning electron microscope "S-4800" (manufactured by Hitachi, Ltd.). The toner to which the external additive is externally added is observed, and the major axis of 100 primary particles of the external additive is randomly measured in a field of view magnified up to 200,000 times to obtain the number average particle diameter. The observation magnification is appropriately adjusted depending on the size of the external additive.

Various methods are conceivable as means for allowing the positively charged particles to be present on the surface of the toner particles, and any method may be used, but a method of applying by external addition is preferable. It has been found that when the Martens hardness of the toner is within the range of the present invention, the positively charged particles can be uniformly present on the surface of the toner particles. The fixing rate of the positively charged particles to the toner particles is preferably 5% or more and 75% or less, and more preferably 5% or more and 50% or less. When the sticking ratio is within this range, the transfer efficiency can be maintained high by promoting the triboelectric charging of the toner particles and the positively charged particles. The method of measuring the sticking rate will be described later.

Preferred types of positively charged particles include hydrotalcite, titanium oxide, and melamine resin. Of these, hydrotalcite is particularly preferable.

<Measurement method of fixing rate of positively charged particles>
In the method for measuring the sticking rate of the organosilicon polymer, the element to be measured is the element contained in the positively charged particles. For example, in the case of hydrotalcite, magnesium and aluminum are measured. Otherwise, the fixing rate of positively charged particles is measured by the same method.

The toners produced are shown below.

[Toner 1]
(Preparation process of aqueous medium 1)
To 1000.0 parts of ion-exchanged water in the reaction vessel, 14.0 parts of sodium phosphate (12 hydrate manufactured by Lhasa Kogyo Co., Ltd.) was charged, and the temperature was kept at 65° C. for 1.0 hour while purging with nitrogen.

T. K. Using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), while stirring at 12000 rpm, an aqueous solution of calcium chloride in which 9.2 parts of calcium chloride (dihydrate) was dissolved in 10.0 parts of ion-exchanged water was collected. Then, an aqueous medium containing the dispersion stabilizer was prepared. Furthermore, 10 mass% hydrochloric acid was added to the aqueous medium to adjust the pH to 5.0, and thus an aqueous medium 1 was obtained.

(Hydrolysis step of organosilicon compound for surface layer)
60.0 parts of ion-exchanged water was weighed in a reaction vessel equipped with a stirrer and a thermometer, and the pH was adjusted to 3.0 using 10% by mass of hydrochloric acid. This was heated with stirring to bring the temperature to 70°C. Thereafter, 40.0 parts of methyltriethoxysilane, which is an organosilicon compound for the surface layer, was added and stirred for 2 hours or more for hydrolysis. The end point of the hydrolysis was visually confirmed by the fact that the oil and water did not separate to form a single layer, and it was cooled to obtain a hydrolyzed solution of the organosilicon compound for the surface layer.

(Process for preparing polymerizable monomer composition)
-Styrene: 60.0 parts-C.I. I. Pigment Blue 15:3:6.5 parts The above materials were put into an attritor (manufactured by Mitsui Miike Kakoki Co., Ltd.), and further dispersed using zirconia particles having a diameter of 1.7 mm at 220 rpm for 5.0 hours to prepare a pigment. A dispersion was prepared. The following materials were added to the pigment dispersion.
-Styrene: 20.0 parts-n-butyl acrylate: 20.0 parts-Crosslinking agent (divinylbenzene): 0.3 parts-Saturated polyester resin: 5.0 parts (Propylene oxide-modified bisphenol A (2 mol addition product) Polycondensate of terephthalic acid (molar ratio 10:12), glass transition temperature Tg=68° C., weight average molecular weight Mw=10000, molecular weight distribution Mw/Mn=5.12)
Fischer-Tropsch wax (melting point 78° C.): 7.0 parts This was kept warm at 65° C. K. A homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was used to uniformly dissolve and disperse at 500 rpm to prepare a polymerizable monomer composition.
(Granulation Step) The temperature of the aqueous medium 1 is 70° C. K. While maintaining the rotation speed of the homomixer at 12000 rpm, the polymerizable monomer composition was charged into the aqueous medium 1, and 9.0 parts of t-butylperoxypivalate as a polymerization initiator was added. Granulation was performed for 10 minutes while maintaining 12,000 rpm with the stirring device.

(Polymerization process)
After the granulation step, the stirrer was changed to a propeller stirring blade to carry out polymerization for 5.0 hours while maintaining 70°C while stirring at 150 rpm, and the polymerization reaction was performed by heating to 85°C and heating for 2.0 hours. To obtain core particles. When the temperature of the slurry was cooled to 55° C. and the pH was measured, it was pH=5.0. While continuing stirring at 55° C., 20.0 parts of the hydrolyzed liquid of the organosilicon compound for the surface layer was added to start the surface layer formation of the toner. After maintaining as such for 30 minutes, the pH of the slurry was adjusted to 9.0 for completion of condensation using an aqueous solution of sodium hydroxide, and the slurry was further maintained for 300 minutes to form a surface layer.

(Washing and drying process)
After the completion of the polymerization process, the toner particle slurry is cooled, hydrochloric acid is added to the toner particle slurry to adjust the pH to 1.5 or less, and the mixture is left to stir for 1 hour, followed by solid-liquid separation with a pressure filter to obtain a toner cake. Got This was reslurried with ion-exchanged water to form a dispersion again, and then solid-liquid separation was performed with the above-mentioned filter. The reslurry and solid-liquid separation were repeated until the electric conductivity of the filtrate became 5.0 μS/cm or less, and finally solid-liquid separation was performed to obtain a toner cake.

The obtained toner cake was dried using a flash jet dryer, a flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.), and fine coarse powder was cut using a multi-division classifier utilizing the Coanda effect to obtain toner particles 1. The drying conditions were such that the blowing temperature was 90° C., the dryer outlet temperature was 40° C., and the toner cake supply rate was adjusted so that the outlet temperature did not deviate from 40° C. according to the water content of the toner cake.

It was confirmed that silicon atoms were present in the surface layer by performing silicon mapping in cross-sectional TEM observation of the toner particles 1. Also in the following toner production examples, it was confirmed by the same silicon mapping that the surface layer containing the organic silicon polymer had silicon atoms in the surface layer. In this production example, the obtained toner particles 1 were used as the toner 1 as they were without external addition.

The evaluation method performed on Toner 1 will be described below.

<Measurement of Martens hardness>
The measurement was performed by the method described in "Method of measuring toner hardness".

<Method of measuring sticking rate>
The measurement was carried out by the method described in "Measurement Method of Organosilicon Polymer Sticking Ratio".

[Toner 2, Toner 3]
A toner was prepared in the same manner as Toner 1, except that the conditions for adding the hydrolyzed liquid in the (polymerization step) and the holding time after the addition were changed as shown in Table 1. The pH of the slurry was adjusted with hydrochloric acid and sodium hydroxide aqueous solution. Table 1 shows the measurement results of the obtained toner 2 and toner 3.

[Toner 4]
Toner 1 was externally added as shown in Table 2 to prepare Toner 4. As the method of external addition, 100 parts of the toner particles were charged with SUPERMIXER PICCOLO SMP-2 (manufactured by Kawata Co., Ltd.) in the number of parts shown in Table 2 and mixed at 3000 rpm for 10 minutes. Table 1 shows the measurement results of the obtained toner.

[Toner 5]
Toner 5 was produced in the same manner as in Toner 1, except that the conditions for adding the hydrolysis liquid in the (polymerization step) and the holding time after addition were changed as shown in Table 1. The evaluation results of the obtained toner are shown in Table 1.

[Toner 6]
(Hydrolysis step of organosilicon compound for surface layer) was not performed. Instead, 30 parts of methyltriethoxysilane, which is an organosilicon compound for the surface layer, was added as a monomer (step of preparing a polymerizable monomer composition).

In the (polymerization step), after cooling to 70° C. and measuring the pH, the hydrolysis solution was not added. While continuing stirring at 70° C., the pH of the slurry was adjusted to 9.0 for completion of condensation with an aqueous sodium hydroxide solution, and the slurry was further held for 300 minutes to form a surface layer.

The evaluation results of Toner 6 thus obtained are shown in Table 1.

In the table, DHT-4A is manufactured by Kyowa Chemical Industry Co., Ltd.

(Cleaning blade)
<Structure of cleaning blade>
The cleaning blade 8 of the present invention includes an elastic member 8a and a support member 8b that supports the elastic member. The elastic member has a first surface M1 and a second surface M2 that form an edge ED that contacts the member to be cleaned. A surface located on the upstream side in the rotation direction of the photosensitive drum is a first surface, and a downstream surface is M2.

In the cleaning blade of the present invention, the "free end" of the elastic member is the end of the elastic member opposite to the end supported by the support member. The “free end portion” of the elastic member is the free end and its vicinity. The "edge" is a contact portion of the cleaning blade that contacts the member to be cleaned, and is a ridge portion formed by the intersection of the first surface and the second surface.

The cleaning blade of this example can be obtained by arranging a supporting member in a mold, injecting a raw material composition such as polyurethane elastomer into the mold, heating and reacting to cure and releasing the mold. After releasing from the mold, the tip of the free end of the elastic member and both ends of the elastic member in the longitudinal direction can be cut as necessary.

The formation of the portion having the dynamic hardness DHs and 0.07≦DHs≦1.1 in the free end portion can be realized by providing a hardening step of the free end portion. The step of forming the hardened region at the tip of the elastic member may be performed before or after cutting. This makes it possible to obtain a cleaning blade in which the elastic member and the support member are integrated.

[Supporting member]
The material forming the support member of the cleaning blade of the present invention is not particularly limited, and examples thereof include the following materials. Metallic materials such as steel plate, stainless steel plate, galvanized steel plate, chrome-free steel plate, resin materials such as 6-nylon and 6,6-nylon. Further, the structure of the support member is not particularly limited. One end of the elastic member of the cleaning blade is supported by the supporting member.

[Elastic member]
Examples of the material forming the elastic member of the cleaning blade 6 of the present invention include the following materials. Polyurethane elastomer, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine Rubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, polysulfide rubber, etc. As the polyurethane elastomer, a polyester urethane elastomer is preferable because it has excellent mechanical properties. Polyurethane elastomer is a material mainly obtained from raw materials such as polyisocyanate, polyol, chain extender, catalyst and other additives.

[Cured area forming part]
The portion where the hardened region is formed at the tip of the elastic member is at least one of the first surface and the second surface that is in contact with the member to be cleaned. Moreover, what hardened the inside of this surface vicinity can also be used.

The hardened region may be further formed on the other surface of the tip portion of the elastic member, that is, the surface facing the second surface, and both end surfaces in the longitudinal direction of the elastic member. In this case, the rigidity of both end surface portions of the elastic member can be improved.

[Shape of elastic member]
In the elastic member of the present invention, the angle of the edge formed by the first surface and the second surface is not particularly limited, but is usually about 85 to 95 degrees.

The international rubber hardness (IRHD) of the elastic member of the present invention is preferably 60 degrees or more, and more preferably 65 degrees or more.

<Method of manufacturing cleaning blade>
[Method of forming cured area]
The method of forming the hardened area on the tip portion can be performed by applying a material for forming the hardened area and hardening the material. The material for forming the cured region is used by diluting it with a diluting solvent as necessary, and can be applied by a known means such as dipping, spraying, dispenser, brush coating, roller coating and the like. An isocyanate compound or the like can be used as the material for forming the cured region. Further, in order to allow the high hardness region to exist inside the surface, it is necessary to sufficiently impregnate the elastic member with the material for forming the cured region (isocyanate compound or the like). Since the impregnation is promoted by making the material for forming the hardened region high in concentration and low in viscosity, it is effective to heat the material for forming the hardened region without diluting it. The material temperature is preferably 60° C. or higher.

Hereinafter, an example of a method of forming a hardened area will be described by using an isocyanate compound as a material for forming the hardened area. The elastic member coated with the material for forming the cured region may be referred to as a "precursor".

[Material for forming cured area]
The material for forming the cured region is not particularly limited as long as it is capable of curing the elastic member or capable of forming the cured region on the surface of the elastic member, and is, for example, an isocyanate compound. And acrylic resin. The material forming the cured region may be diluted with a solvent or the like and used. The solvent used for dilution is not particularly limited as long as it dissolves the material used, and examples thereof include toluene, xylene, butyl acetate, methyl isobutyl ketone, and methyl ethyl ketone.

When the constituent material of the elastic member is a polyester urethane elastomer, as the material forming the cured region, considering the compatibility with the elastic member and the impregnation property into the elastic member, the isocyanate compound which is the constituent material of the polyester urethane elastomer is used. It is more preferable to use. As the isocyanate compound brought into contact with the elastic member, one having one or more isocyanate groups in the molecule can be used. As the isocyanate compound having one isocyanate group in the molecule, aliphatic monoisocyanate such as octadecyl isocyanate (ODI) and aromatic monoisocyanate such as phenyl isocyanate (PHI) can be used. As the isocyanate compound having two isocyanate groups in the molecule, those generally used for producing a polyurethane resin can be used, and specific examples thereof include the following. 2,4-Tolylene diisocyanate (2,4-TDI), 2,6-Tolylene diisocyanate (2,6-TDI), 4,4′-Diphenylmethane diisocyanate (MDI), m-Phenylene diisocyanate (MPDI), Tetra Methylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI) and the like. Moreover, as an isocyanate compound having three or more isocyanate groups in the molecule, for example, 4,4′,4″-triphenylmethane triisocyanate, 2,4,4′-biphenyltriisocyanate, 2,4,4′ -Diphenylmethane triisocyanate, etc. can be used.In addition, an isocyanate compound having two or more isocyanate groups can also be used as a modified derivative or a polymer thereof. Above all, in order to efficiently increase the hardness of the cured region, The MDI having high crystallinity, that is, the structure having symmetry is preferable, and the MDI containing the modified product is more preferable in terms of workability since it is liquid at room temperature.

It is further preferable that the hardening region is formed on both of the first surface and the second surface that form an edge of the elastic member that contacts the member to be cleaned. This is because both the first surface and the second surface may contact the image carrier during cleaning.

<Method of measuring hardness of cleaning blade>
In the present invention, the hardness of the cured region can be measured by the following method. As a measuring machine, "Shimadzu dynamic ultra-micro hardness meter DUH-W211S" manufactured by Shimadzu Corporation can be used. As the indenter, a 115° triangular cone indenter is used, and the dynamic hardness can be obtained by the following calculation formula.
Dynamic hardness: DHs=α×P/D2
In the formula, α represents a constant depending on the shape of the indenter, P represents the test force (mN), and D represents the amount of penetration of the indenter into the sample (pushing depth) (μm).

The measurement conditions are as follows.
α: 3.8584,
P: 1.0 mN,
Load speed: 0.03mN/sec,
Hold time: 5 seconds,
Measurement environment: temperature 23 ℃, relative humidity 55%,
Aging of measurement sample: left for 6 hours or longer in an environment of temperature 23°C and relative humidity 55% (method of adjusting measurement sample)
The method for preparing the measurement sample is as follows. The measurement sample is 4 mm in the longitudinal direction (2 mm in both directions from the intermediate point) from each of the three intermediate points (3 points) that divide the longitudinal direction into three equal parts in the image forming area, and in the lateral direction from the edge 7 to 2 mm. Cut out with the dimensions of.

The sample was placed so that the indenter hits the cured surface (first surface) of the cured region of the measurement sample vertically, and the longitudinal direction was 2 mm from the end, and the lateral or thickness direction was 100 μm from the edge ED. Dynamic hardness is measured. This is because the first surface mainly comes into contact with each other at the time of contact and plays a main role of holding the toner.

This measurement is performed on three measurement samples, and the average value thereof is defined as the dynamic hardness DHs of the surface of the cleaning blade.

<Method of manufacturing cleaning blade>
(Production of cleaning blade precursor)
The method for manufacturing the cleaning blade according to the present invention is not particularly limited as long as a suitable method may be selected from known methods. Further, as a method for manufacturing the elastic member, a suitable one may be selected from known methods such as a mold molding method and a centrifugal molding method. For example, in a cleaning blade mold provided with a cavity for forming an elastic member, a support member having an adhesive applied to a contact portion with the elastic member is arranged. On the other hand, a prepolymer obtained by partially polymerizing polyisocyanate and a polyol and a curing agent containing a polyol, a chain extender, a catalyst, and other additives are put into a casting machine, and mixed and stirred at a constant ratio in a mixing chamber. Then, a raw material composition such as a polyurethane elastomer is obtained. The raw material composition is poured into the mold to form a cured molded product (elastic member) on the adhesive-coated surface of the support member, and the mold is removed after reaction curing. If necessary, the elastic member is appropriately cut in order to secure the predetermined size and the edge dimensional accuracy of the contact portion of the elastic member, and a cleaning blade precursor in which the supporting member and the elastic member are integrally molded is formed. It can be manufactured.

When the elastic member is manufactured by a centrifugal molding machine, a prepolymer obtained by partially polymerizing polyisocyanate and a polyol, and a curing agent containing a polyol, a chain extender, a catalyst, and other additives are mixed and stirred. A raw material composition such as a polyurethane elastomer is put into a rotating drum to obtain a polyurethane elastomer sheet. This polyurethane elastomer sheet is cut in order to ensure a predetermined size and edge dimensional accuracy of the contact portion of the elastic member. The polyurethane elastomer sheet (elastic member) thus obtained can be attached to a support member coated with an adhesive to produce a cleaning blade precursor.

(Formation of hardening area)
The hardened region can be formed by the method described above. That is, first, a material for forming a hardened region is applied to the first surface and the second surface of the tip portion of the elastic member of the cleaning blade precursor. Next, the tip portion of the elastic member is heat-treated at a temperature of 80° C. or higher for 3 minutes or longer. As a result, a hardened region can be formed on the surface and inside of the tip of the elastic member.

When it is necessary to cut the elastic member in order to form the edge for contacting the member to be cleaned on the cleaning blade, the hardening region may be formed before or after the cutting. In the case of centrifugal molding, the hardened region can be formed before being joined to the support member. The cleaning blade can be obtained as described above.

Hereinafter, an example of the manufactured cleaning blade will be shown.

[Cleaning blade 1]
In this manufacturing example, an integrally molded type cleaning blade shown in FIG. 3 was manufactured and evaluated.

1. Support Member A 1.6 mm thick galvanized steel plate was prepared and processed to obtain a support member 8b having an L-shaped cross section. An adhesive (product name: Chemlock 219, manufactured by Road Corporation) for bonding a polyurethane resin was applied to a portion of the support member that was brought into contact with the elastic member 8a.

2. Preparation of Raw Material for Elastic Member The materials shown in the column of Component 1 in Table 1 were reacted with stirring at 80° C. for 3 hours to obtain a prepolymer having a molar concentration of isocyanate of 8.50%. A polyurethane elastomer having a molar ratio (α value) of 0.60 of a hydroxyl group to an isocyanate group of 0.60 is obtained by mixing 1000 g of this prepolymer with 212.9 g of a curing agent composed of the materials of the types and amounts shown in the column of Component 2 in Table 1. A composition was prepared and used as a raw material for an elastic member.

3. Integral molding of support member and elastic member The polyurethane elastomer composition is injected into a molding die for a cleaning blade, which is arranged so that the adhesive application portion of the support member is projected into the cavity, and is cured at 130° C. for 2 minutes. After that, the mold was removed to obtain an integrally molded body of the elastic member and the supporting member.

This integrally molded body was appropriately cut before forming the cured region, and the edge angle was 90 degrees, and the distances in the lateral direction, the thickness direction, and the longitudinal direction of the elastic member were 7.5 mm, 1.6 mm, and 237 mm, respectively.

4. Formation of Hardened Area Modified MDI (trade name; Millionate MTL, manufactured by Tosoh Corporation) was prepared as a material for forming a hardened area. The material for forming a hardened region is heated to 90° C., and the other five surfaces except the surface (the reference numeral 11 in FIG. 2) facing the supporting member are immersed in the material so as to be immersed in the integrally molded body. The elastic member was dipped for 30 seconds to apply the material on each surface. Then, the material for forming a hardened region on the surface of the elastic member was wiped off with a sponge soaked with butyl acetate as a solvent.

In this way, the cured regions were formed on the five surfaces of the elastic member (the first surface, the second surface, the surface facing the second surface, both end surfaces in the longitudinal direction) and the interiors below the surfaces. The cleaning blade 1 was obtained. The cured region was formed 24 hours after the elastic member was molded.

[Cleaning blade 2]
The cleaning blade was formed under the same conditions as the cleaning blade 1 except that the step of forming the cured region was omitted.

[Cleaning blade 3]
Under the same conditions as the cleaning blade 2, except that a polyurethane elastomer composition having a molar ratio (α value) of hydroxyl groups to isocyanate groups of 0.90 was prepared and used as the raw material for the elastic member in the method for preparing and producing the elastic member raw material. The cleaning blade 3 was formed. No treatment for forming a cured region was performed.

[Cleaning blade 4]
A cleaning blade 4 was obtained under the same conditions as those of the cleaning blade 1 except that the temperature of the material for forming a hardened area was changed to 90° C. and the dipping time was changed to 90 seconds in forming the hardened area.

[Cleaning blade 5]
A cleaning blade 5 was obtained under the same conditions as the cleaning blade 1 except that the temperature of the material for forming a hardened area was changed to 90° C. and the dipping time was changed to 150 seconds in forming the hardened area.

Table 4 shows the manufacturing conditions of the prepared cleaning blade and the measurement results of the dynamic hardness.

(Position relationship between cleaning blade and photoconductor drum)
In the blade having the above characteristics and having a slightly deformed tip, in order to generate a force necessary for cleaning toner having a Martens hardness of 200 MPa to 1100 MPa, a set angle is 18 to 26° and an intrusion amount is 0.6 to 1 0.4 mm is preferred.

The set angle of the cleaning blade and the amount of penetration are defined as follows.

(1) Set angle The tangent line of the photosensitive drum when the cleaning blade is placed at the virtual point F where its elastic edge just contacts the photosensitive drum, and the plane on the downstream side in the rotational direction of the photosensitive drum that sandwiches the edge of the cleaning blade Angle θ. Figure 4(a)
(2) Penetration amount A movement amount δ when the cleaning blade is moved in a direction of 90° from the imaginary point F with the tangent line in a direction of contacting the photosensitive drum. Figure 4(b)
The cleaning blade is fixed so that the edge of the cleaning blade is located at the above positions (1) and (2) without the photosensitive drum. When fixed and brought into contact with the photosensitive drum, the actual cleaning blade is deformed into a shape as shown in FIG.

(Example)
As Examples 1 to 6 and Comparative Examples 1 to 4, combinations of toners 1 to 6 and cleaning blades 1 to 5 as shown in Table 5 were prepared.

(Experiment)
(torque)
The developer chamber 18 of the process cartridge 7 was filled with 100 g of the toners of Examples 1-6 and Comparative Examples 1-4. Similarly, the cleaning blades of Examples 1 to 6 and Comparative Examples 1 to 4 were attached to the photoconductor unit 13, and the setting angle θ22° and the penetration amount δ1.0 mm were set.

At room temperature of 15° C. and relative humidity of 10% Rh, with the developing roller in contact with the developing roller, the charging roller is −1 kV and the developing roller is grounded while rotating at the photosensitive member surface speed of 296 mm/s and the developing roller surface speed of 425 mm/s. -100V was applied to the supply roller and the regulating member.

The photoconductor drive torque was measured for 2 seconds after 30 seconds had elapsed from the start of rotation. The evaluation was performed as follows.
A: Good low torque 0.16 N·m or less B: Low torque effect 0.16 N·m or more and 0.18 N·m or less C: No low torque effect observed 0.18 N·m or more.
The evaluations of A and B were determined to have the effect of reducing the torque. The results are shown in Table 5, "Torque" column.

(Dirt of charging member)
For the examples in which the torque evaluations were A and B, the image forming apparatus 100 formed an image on 15,000 sheets with a printing rate of 1% in an environment of room temperature of 15° C. and relative humidity of 10% Rh. An intermittent time of 3 seconds was set for every two sheets of image formation.

The surface speed of the photosensitive member was 296 mm/s, the surface speed of the developing roller was 425 mm/s, the surface potential of the photosensitive member was -500 V, the applying voltage of the developing roller was -350 V, the voltage of the supplying roller was -450 V, and the voltage of the regulating member was -450 V.

The degree of smearing of the charging roller after image formation on 15,000 sheets was evaluated. The evaluation was performed as follows.
A: No stain on the eye and no effect on the image B: Slight stain on the eye but no effect on the image C: Stain on the eye and influence on the image The effect on the image is a halftone image. Those having streaks due to contamination of the charging roller in the recording material conveyance direction are considered to have an influence.

The results are shown in the column of "Contamination of charging member" in Table 5. A and B, which had no effect on the image, were considered to have the effect of the invention.

In Examples 1 to 6, the torque was 0.18 N·m or less, and it was found that the torque could be reduced.

By setting the adhesion rate of the surface layer of the organosilicon polymer to the toner, which is the developer, to 90% or more, the contact portion between the cleaning blade 6 and the photoconductor drum, which is the image carrier, as shown in FIG. A small amount of the organic silicon polymer surface layer particles peeled from the toner is obtained. As a result, when the toner particles T having a Martens hardness of 200 to 1100 MPa and which are difficult to deform are sandwiched between the cleaning blade and the photoconductor drum, they act as spacers, and the contact area is reduced and the torque is reduced.

In this state, by setting the dynamic hardness of the cleaning blade to DHs of 0.07 to 1.1, sufficient force can be applied to the toner particles, slipping does not occur, and contamination of the charging member can be prevented.

In Comparative Example 1, since the Martens hardness of the toner was high, the toner sandwiched between the contact portions damaged the photosensitive drum, and the toner and the organosilicon polymer slipped from the scratched portion.

In Comparative Example 2, the toner had a low Martens hardness and the organosilicon fixing rate was 90% or less, so the torque was high. Although 15,000 sheets have not been printed, the charging member is contaminated in the torque measurement test, and it is expected that the charging member will be contaminated during long-term use.

When the Martens hardness of the toner is 200 MPa or less, the toner deforms flat at the contact portion as shown in FIG. 5B, and the contact area between the elastic body and the photoconductor via the toner increases and the torque increases. Further, as shown in FIG. 5(c), the silicon polymer surface layer peeled from the toner in the cleaning section or other places fills the gap formed by the cleaning blade, the toner and the photosensitive drum (see FIG. 5). It is considered that the torque increased because the contact area increased.

In Comparative Example 3, since the hardness of the cleaning blade was too low, sufficient pressure did not act on the toner, the toner slipped out from the contact portion, and the charging member was contaminated.

In Comparative Example 4, since the cleaning blade has a high hardness and the deformation is extremely small, the toner is not caught in the contact portion. Further, since the fixing rate is high, the cleaning blade and the photoconductor drum come into direct contact with each other, and the cleaning blade is chipped due to durability, and the toner slips through the chipping, which appears as dirt on the charging member.

(Position range of cleaning blade that can achieve both low torque and durable high image quality)
With respect to the configuration of Example 1, the setting angle θ and the penetration amount δ were variously changed, and the torque was measured at room temperature of 15° C. and relative humidity of 10% Rh. The results are shown in Table 6. The symbols are as shown in Table 5. When the set angle is 18 to 26° and the penetration amount is 0.6 to 1.4 mm, the torque is 0.2 N·m or less.

Further, 15,000 sheets of 1% printing rate image formation was performed in an environment of room temperature of 15° C. and relative humidity of 10% Rh. The results are shown in Table 7. As for the cleaning property, the greater the penetration amount, the greater the contact force of the contact portion and the better the cleaning property. Therefore, it was found that the cleaning can be preferably performed in the range of 0.6 to 1.4 mm and the set angle of 18 to 26°.

From the above, 18 to 26°, 0.6 to 1.4 mm, and more preferably 20 to 24° are maintained in order to maintain the torque reduction effect while appropriately cleaning the toner of the present invention by applying sufficient pressure. , 0.9 to 1.2 mm.

In the region where the penetration amount is less than 0.6 mm or the setting angle is less than 18°, the cleaning blade has low followability in an environment where the room temperature is 10° C. and the relative humidity is 15% Rh. Due to the unevenness, the toner may slip through in a band shape.

Further, when the penetration amount is 1.4 mm or more or the setting angle exceeds 26°, the cleaning blade may be turned over in an environment of room temperature of 30° C. and relative humidity of 80% Rh.

As described above, according to the present invention, the contact area between the photosensitive drum and the cleaning blade can be kept small, and a sufficient holding pressure can be applied to the toner at the contact portion. As a result, it is possible to provide a process cartridge in which the photosensitive member driving torque is low and there is no problem of streak images and density unevenness due to contamination of the charging member.

1 photoconductor drum, 2 charging roller, 3 developing unit, 4 developing roller,
5 supply roller, 6 developer regulating blade, 7 process cartridge,
8 cleaning blade, 9 toner recovery container, 10 developer,
12 recording material, 13 photoconductor unit, 17 developing chamber, 18 developer accommodating chamber,
22 stirring sheet, 30 scanner, 31 intermediate transfer belt,
32 primary transfer roller, 33 secondary transfer roller, 34 fixing device,
35 intermediate transfer belt cleaner, 100 image forming apparatus

Claims (3)

A developer, a developing device, an image carrier for carrying a developer image formed by developing the electrostatic latent image by the developer, a charging member, and a contact portion for contacting the image carrier, A process cartridge having a cleaning member for cleaning the surface of the image carrier by a contact portion,
The developer in the surface layer _{R0-SiO 3/2} (R0 carbon 6 alkyl group) include organosilicon polymer represented by,
The fixing rate of the organosilicon polymer to the developer is 90% or more,
The Martens hardness when measured under the condition of the maximum load of 2.0×10 −4 N is 200 MPa or more and 1100 MPa or less,
The dynamic hardness of the contact portion of the cleaning member with the image carrier is DHs, and the dynamic hardness is
0.07 (mN/μm2)≦DHs≦1.1 (mN/μm2)
Process cartridge characterized in that When the set angle θ and the penetration amount δ are set in the contact posture of the cleaning member with respect to the image carrier,
18≦θ≦26 (°),
0.6≦δ≦1.4 (mm)
The process cartridge according to claim 1, wherein An image forming apparatus comprising the process cartridge according to claim 1 or 2 detachably.