JP7259613B2 - Process cartridge, image forming apparatus, and image forming method - Google Patents

Description

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

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, an image bearing member (hereinafter also referred to as a "photoreceptor") as a member to be cleaned has a surface after a toner image has been transferred to a transfer sheet or an intermediate transfer member. It is known that the adhering matter such as unnecessary transfer residual toner is removed by cleaning means.

As a cleaning member of the cleaning means, a strip-shaped cleaning blade is well known because of its simple structure and excellent cleaning performance (see, for example, Patent Document 1). In this method, the base end of the cleaning blade is supported by a supporting member, and the abutment portion (tip edge portion) is pressed against the peripheral surface of the image carrier to block and scrape off the toner remaining on the image carrier. .

In recent years, the cleaning blade has been required to have a long service life. However, if the cleaning blade is used for a long period of time, wear, chipping, turning, etc. occur at the contact portion with the image bearing member, resulting in poor cleaning performance. There is a problem that an abnormal image is generated due to toner passing through.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process cartridge capable of maintaining cleanability over a long period of time and suppressing filming on an image carrier over a long period of time.

Means for solving the problems of the present invention are as follows.
an image carrier;
a developing means provided with the toner for developing the electrostatic latent image formed on the image carrier with the toner to form a visible image;
cleaning means for removing residual toner remaining on the image carrier with a cleaning blade;
A process cartridge having
the cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner remaining on the image carrier;
The elastic member has a base material and a surface layer provided on the base material,
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the substrate including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction,
The Martens hardness HM has a measured value at a load of 1 μN and a measured value at a load of 1000 μN of 2.5 N/mm ² or more and 32.5 N/mm ² or less,
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less,
A process cartridge, wherein the toner contained in the developing means has a circularity of less than 0.950 and a content of fine powder of 2 μm or less of 20% by number or more and 60% by number or less.

According to the present invention, it is possible to provide a process cartridge that can maintain cleanability over a long period of time and can suppress filming on an image carrier over a long period of time.

FIG. 1 is an enlarged cross-sectional view showing an example of a state in which an example of a cleaning blade used in the present invention is in contact with the surface of an image carrier. FIG. 2 is a perspective view showing an example of a cleaning blade used in the present invention. FIG. 3A is a diagram illustrating an example of a method for manufacturing a cleaning blade used in the present invention. FIG. 3B is a diagram explaining another example of the method for manufacturing the cleaning blade used in the present invention. FIG. 4 is an explanatory diagram of elastic power. FIG. 5 is a schematic configuration diagram showing an example of an image forming apparatus according to the present invention. FIG. 6 is a schematic configuration diagram showing an example of an image forming unit included in the image forming apparatus according to the present invention. FIG. 7 is a diagram for explaining how cleaning is performed over time according to the present invention. FIG. 8 is a diagram for explaining an example of a method for measuring the average thickness of the surface layer. FIG. 9A is a diagram showing a state in which the tip ridge of a conventional cleaning blade is curled. FIG. 9B is a diagram illustrating local wear of the tip surface of the cleaning blade. FIG. 9C is a diagram showing a state in which the edge line portion of the cleaning blade is missing. FIG. 10 is a diagram for explaining cut-out portions of the base material when measuring the Martens hardness (HM) of the base material. FIG. 11A is a diagram for explaining the measurement positions of the Martens hardness (HM) of the substrate (No. 1). FIG. 11B is a diagram for explaining the measurement positions of the Martens hardness (HM) of the substrate (No. 2). FIG. 11C is a diagram for explaining the measurement positions of the Martens hardness (HM) of the substrate (No. 3).

A process cartridge, an image forming apparatus, and an image forming method according to the present invention will be described below with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below, and can be changed within the scope of those skilled in the art, such as other embodiments, additions, modifications, deletions, etc. is also included in the scope of the present invention as long as the functions and effects of the present invention are exhibited.

(Process cartridge, image forming apparatus, and image forming method)
The process cartridge of the present invention has at least an image carrier, developing means and cleaning means, and further has other means as necessary.
The image forming apparatus of the present invention has at least an image carrier, developing means and cleaning means, and further has other means as necessary.
The image forming method of the present invention uses, for example, the process cartridge of the present invention.

The cleaning means is means for removing residual toner remaining on the image carrier with a cleaning blade.
The cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner (deposits) remaining on the image carrier, which is a member to be cleaned.
The elastic member has a base material and a surface layer provided on the base material.
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the base material including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction.
The Martens hardness HM is 2.5 N/mm 2 or more and 32.5 N/mm ^{2 or} less when measured at a load of 1 μN and at a load of 1000 μN.
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less.
The toner provided in the developing means has a circularity of less than 0.950 and a fine powder content of 2 μm or less of 20% by number or more and 60% by number or less.
According to the process cartridge, the image forming apparatus, and the image forming method, it is possible to maintain cleanability over a long period of time and to suppress filming on the image carrier over a long period of time. Even if the nip width of the cleaning blade widens over time and the peak pressure drops, the penetration of toner into the nip is suppressed and cleaning performance is maintained, and cleaning is achieved even with a small amount of external additive. It is thought that this is because filming of the external additive to the photoreceptor can be suppressed over time.

<Cleaning Means>
The cleaning means is means for removing residual toner remaining on the image carrier with a cleaning blade.

<<Cleaning Blade>>
Conventionally, when a polymerized toner having a small particle size and excellent sphericity is used, there is a problem that the toner slips through a slight gap formed between the cleaning blade and the image carrier. In order to suppress the slip-through, it is necessary to increase the contact pressure between the image carrier and the cleaning blade to improve the cleaning performance. However, when the contact pressure of the cleaning blade is increased, as shown in FIG. 9A, the frictional force between the image carrier 123 and the cleaning blade 62 increases, and the cleaning blade 62 is pulled in the movement direction of the image carrier 123. , the edge line portion 62c of the cleaning blade 62 is turned over. When the turned-up cleaning blade 62 is restored to its original state against the turning-up, abnormal noise may be generated.

Further, if cleaning is continued with the tip ridge 62c of the cleaning blade 62 turned up, as shown in FIG. A large amount of wear X occurs. If cleaning is continued in such a state, this localized wear will increase. Ultimately, as shown in FIG. 9C, the tip ridgeline portion 62c is lost. If the edge line portion 62c is missing in this manner, the toner cannot be cleaned normally, and there is a problem that cleaning failure occurs. 9A to 9C, 62b is the lower surface of the cleaning blade (blade lower surface).

On the other hand, the cleaning blade (hereinafter sometimes simply referred to as blade) used in the present invention is as follows.
The cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner (deposits) remaining on the image carrier, which is a member to be cleaned.
The elastic member has a base material and a surface layer provided on the base material.
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the base material including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction.
The Martens hardness HM is 2.5 N/mm 2 or more and 32.5 N/mm ^{2 or} less when measured at a load of 1 μN and at a load of 1000 μN.
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less.
Here, the hardness gradient specifically means the Martens hardness HM near the surface of the surface layer in the present invention (load: 1 μN), the deepest portion in the film thickness direction (load: 1000 μN), and the intermediate portion (load: 50 μN). can be grasped by measuring

An embodiment of a cleaning blade used in the present invention will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is an explanatory view of a state in which the cleaning blade 62 is in contact with the surface of the photoreceptor 3, and FIG. 2 is a perspective view of the cleaning blade 62. As shown in FIG. In the illustrated cleaning blade 62, a supporting member 621, an elastic member 624, a base material 622, and a surface layer 623 are illustrated, and the base material 622 in this embodiment has a rectangular shape. A blade tip surface 62a, a blade lower surface 62b, and a tip ridgeline portion 62c (also referred to as an abutment portion, an edge portion, etc.) are also illustrated.

In the present invention, the lower surface of the base material is defined as a longitudinal surface of the base material that constitutes the elastic member and faces the downstream side in the direction of travel (rotational direction in this embodiment) of the image bearing member that is the member to be cleaned. The surface of the tip facing the upstream side in the rotational direction of the member to be cleaned, including the ridgeline portion of the tip of the base material, is referred to as the tip surface of the base material.
In the longitudinal direction of the elastic member, the surface facing the downstream side in the rotational direction of the member to be cleaned is referred to as the lower surface of the blade. The surface is called the blade tip surface.

In FIG. 1, the surface facing the downstream side B in the traveling direction of the member to be cleaned is the blade lower surface 62b, and the tip surface (blade tip surface 62a) facing the upstream side A in the traveling direction of the member to be cleaned is the blade tip surface. .
Further, the contact portion of the elastic member that contacts the surface of the member to be cleaned includes the edge line portion of the elastic member. In addition, when the ridgeline of the tip is turned over or when the line pressure is high, a portion of the tip surface of the blade can also be the abutting portion.

In the present invention, the average film thickness of the surface layer of the contact portion of the cleaning blade is preferably 10 μm or more and 500 μm or less. Stick-slip can be suppressed. Furthermore, even if it wears out due to long-term use, the thick surface layer prevents the base material of the elastic member from being exposed, suppresses an increase in torque and squeals, and maintains these functions. As a result, it is possible to achieve both reduction of curling and abrasion resistance of the blade, and to maintain good cleaning performance over a long period of time. In addition, since it is possible to prevent the base material of the elastic member from contacting the image carrier, it is possible to suppress an increase in torque and an increase in the load applied to the rotation of the image carrier. can do. The cleaning blade of the present invention is not limited to the tandem system.

Since the average film thickness of the surface layer of the contact portion is 500 μm or less, the flexibility of the elastic member of the base material is maintained, and the ability to follow vibrations due to axial vibration of the image carrier and minute undulations on the surface of the image carrier. is improved, and defective cleaning is prevented. Moreover, when the average film thickness is 10 μm or more, abnormal noise due to abnormal wear or the like can be prevented.

More preferably, the average film thickness of the surface layer of the contact portion of the cleaning blade is 50 μm or more and 200 μm or less. By setting the thickness to 50 μm or more and 200 μm or less, it is possible to make it more difficult for the contact portion to turn over in the initial stage, and even if the wear progresses, the wear can be stopped within the surface layer, and the exposure of the base material of the elastic member can be suppressed. , Turning up, squealing, and cleaning failures are less likely to occur even after long-term use.

Here, the average film thickness of the surface layer of the contact portion can be obtained from the arithmetic mean value obtained by measuring 10 arbitrary locations of the surface layer of the contact portion. The method for measuring the thickness is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a method of measuring a cut surface including the surface layer of the contact portion using a microscope. Specifically, for example, the thickness of the surface layer at a position of 50 μm to 200 μm from the tip of the contact portion (contact side) is measured. In addition, it is usually measured at positions excluding 2 cm from both ends in the longitudinal direction (direction of the contact side).

-Manufacturing method of cleaning blade-
Conventionally, it is difficult to have a thick film on the surface layer of the contact part with the previous blade that was manufactured by spray or dip coating. was less than In addition, in such a way of attaching the film, the abutting portion is rounded, and the edge accuracy is deteriorated. For this reason, the cleanability may have deteriorated.

Further, in the prior art, for example, Japanese Patent No. 5515865, a long sheet material made of polyurethane rubber is impregnated with an impregnating agent, then cut, and a coating agent containing a resin is applied and cured to form a coating film. A method of manufacturing a cleaning blade is disclosed comprising the step of forming a In this case, since the coating film is applied later, the film thickness of the edge portion becomes thin, and there is a possibility that the torque increases with time. Japanese Patent No. 2962843 discloses a cleaning blade having a coating layer containing lubricating particles, in which the edge is cut after the coating layer is formed. However, since the lubricating particles are dispersed, the surface roughness of the coating layer increases, and even if the edge is cut after the coating layer is formed, the edge accuracy may deteriorate and the cleanability may deteriorate.

In contrast, in the cleaning blade 62 of this embodiment, a curable composition that forms the surface layer 623 is applied to the base material 622 made of urethane rubber, for example, and then the resin is cured by heat curing. After that, the contact portion is cut to form a blade shape. The surface layer 623 contains a siloxane-based compound and has a hardness gradient in which the hardness decreases from the surface toward the bottom surface of the substrate in the film thickness direction.

The surface layer 623 is formed, for example, by coating at least the edge line portion 62c of the cleaning blade 62 with a curable composition by spray coating, dip coating, die coating, or the like.

The surface layer on the bottom surface of the substrate can be formed by bar coating, spray coating, dip coating, brush coating, screen printing, or the like. The film thickness of the surface layer depends on conditions such as the solid content concentration of the coating liquid, coating conditions (bar coating: gap, spray coating: discharge amount, distance, moving speed, dip coating: lifting speed, etc.), and the number of coatings. It is possible to control by changing it appropriately.

A part of the method for manufacturing the cleaning blade of this embodiment is shown in FIGS. 3A and 3B. 3A and 3B are side views of the elastic member of the cleaning blade. The diagram on the left side of FIG. 3A shows a state in which the curable composition is applied to the substrate 622 and cured. A resilient member 624 shown in FIG. Although the location to be cut can be changed as appropriate, for example, a portion of 1 mm from the tip is cut.
Another example is shown in FIG. 3B. The drawing on the left side of FIG. 3B shows a state in which the curable composition is applied to the substrate 622 and cured, as in FIG. 3A. Here, instead of cutting the tip surface of the base material 622 as in FIG. 3A, the base material 622 is cut near the center. In this case, it is also possible to manufacture two cleaning blades at the same time.
In addition to the above, a method of curing a curable composition using a mold to form a right-angled contact portion may be used.
The method of cutting the base material 622 and the surface layer 623 can be changed as appropriate, and for example, a vertical slicer or the like can be used.
Although the cutting direction can be changed as appropriate, it is preferable to cut from the surface layer 623 side to the base material 622 side. In this case, edge precision can be improved.
In this embodiment, after forming a thick film of the surface layer 623 on the lower surface of the substrate, the edge is cut, thereby achieving both a thick film of the contact portion and edge accuracy.

-Parts to be cleaned-
The material, shape, structure, size, etc. of the member to be cleaned are not particularly limited, and can be appropriately selected according to the purpose. Examples of the shape of the member to be cleaned include a drum shape, a belt shape, a flat plate shape, and a sheet shape. The size of the member to be cleaned is not particularly limited and can be appropriately selected according to the purpose, but a size that is normally used is preferable.
The material of the member to be cleaned is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include metal, plastic, ceramic, and the like.
Further, the member to be cleaned is not particularly limited, and can be appropriately selected according to the purpose. When the cleaning blade is applied to an image forming apparatus, for example, an image carrier can be used.

-deposits-
The adhering matter is not particularly limited as long as it adheres to the surface of the member to be cleaned and can be removed by the cleaning blade, and can be appropriately selected according to the purpose. , inorganic fine particles, organic fine particles, dirt, dust, or a mixture thereof. Among these, toners are preferable, and toners having a glass transition temperature of 50° C. or lower and having low-temperature fixability are particularly preferable.

-Supporting member-
The cleaning blade of this embodiment preferably comprises a support member, and a flat elastic member having one end connected to the support member and the other end having a free end portion of a predetermined length. The cleaning blade is arranged such that a contact portion including a tip ridge line portion, which is one end of the elastic member on the free end side, contacts the surface of the member to be cleaned along the longitudinal direction.

The shape, size, material, etc. of the supporting member are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape of the support member include a plate shape, strip shape, sheet shape, and the like. The size of the support member is not particularly limited, and can be appropriately selected according to the size of the member to be cleaned.

Examples of materials for the support member include metal, plastic, and ceramic. Among these, a metal plate is preferred from the viewpoint of strength, and a steel plate such as stainless steel, an aluminum plate, and a phosphor bronze plate are particularly preferred.

-Base material-
The base material 622 of the elastic member 624 is not particularly limited in its shape, material, size, structure, etc., and can be appropriately selected according to the purpose.
Examples of the shape include plate-like, strip-like, sheet-like, and the like.
The size is not particularly limited, and can be appropriately selected according to the size of the member to be cleaned.
The material is not particularly limited and can be appropriately selected depending on the intended purpose. Polyurethane rubber, polyurethane elastomer, and the like are preferable because high elasticity can be easily obtained.

The method for manufacturing the base material of the elastic member is not particularly limited, and can be appropriately selected according to the purpose. For example, a polyurethane prepolymer is prepared using a polyol compound and a polyisocyanate compound, a curing agent and, if necessary, a curing catalyst are added to the polyurethane prepolymer, crosslinked in a predetermined mold, and placed in a furnace. After post-crosslinking by centrifugal molding, the product is molded into a sheet, left to stand at room temperature and aged, and then cut into a flat plate of a predetermined size.

The polyol compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include high-molecular-weight polyols and low-molecular-weight polyols.
Examples of the high-molecular-weight polyol include polyester polyol which is a condensate of alkylene glycol and an aliphatic dibasic acid; ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene butylene Polyester polyols such as adipate ester polyols, polyester polyols of alkylene glycol and adipic acid such as ethylene neopentylene adipate ester polyols; polycaprolactone polyols such as polycaprolactone ester polyols obtained by ring-opening polymerization of caprolactone; poly( polyether-based polyols such as oxytetramethylene)glycol and poly(oxypropylene)glycol; These may be used individually by 1 type, and may use 2 or more types together.

Examples of the low molecular weight polyol include 1,4-butanediol, ethylene glycol, neopentyl glycol, hydroquinone-bis(2-hydroxyethyl) ether, 3,3′-dichloro-4,4′-diaminodiphenylmethane. , 4,4′-diaminodiphenylmethane and other dihydric alcohols; 1,1,1-trimethylolpropane, glycerin, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolethane, 1, trihydric or higher polyhydric alcohols such as 1,1-tris(hydroxyethoxymethyl)propane, diglycerin, and pentaerythritol; These may be used individually by 1 type, and may use 2 or more types together.

The polyisocyanate compound is not particularly limited and can be appropriately selected depending on the intended purpose. - diisocyanate (NDI), tetramethylxylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), and the like. These may be used individually by 1 type, and may use 2 or more types together.

The curing catalyst is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include amine compounds such as tertiary amines and organometallic compounds such as organic tin compounds. Examples of tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N,N,N',N'-tetramethyl-1,3-butanediamine, aminoalcohols such as dimethylethanolamine, and ethoxyl. amines, ethoxylated diamines, ester amines such as bis(diethylethanolamine) adipate, triethylenediamine (TEDA), cyclohexylamine derivatives such as N,N-dimethylcyclohexylamine, N-methylmorpholine, N-(2-hydroxypropyl )-dimethylmorpholine and other morpholine derivatives, N,N'-diethyl-2-methylpiperazine, N,N'-bis-(2-hydroxypropyl)-2-methylpiperazine and other piperazine derivatives, and the like. Examples of organic tin compounds include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di(2-ethylhexoate), stannous 2-ethylcaproate, and stannous oleate. . These may be used individually by 1 type, and may use 2 or more types together.
The content of the curing catalyst is not particularly limited and can be appropriately selected depending on the intended purpose. % or less is more preferable.

The JIS-A hardness of the base material is not particularly limited and can be appropriately selected depending on the intended purpose. When the JIS-A hardness is 60 degrees or more, the linear pressure of the blade can be easily obtained, and the area of the contact portion with the image bearing member is difficult to expand, so cleaning failures are less likely to occur. Here, the JIS-A hardness of the base material can be measured using, for example, Micro Rubber Hardness Tester MD-1 manufactured by Kobunshi Keiki Co., Ltd.

The impact resilience of the base material conforming to the JIS K6255 standard is not particularly limited, and can be appropriately selected according to the purpose. Here, the impact resilience coefficient of the base material is, for example, conforming to JIS K6255 standard, at 23° C., Toyo Seiki Seisakusho No. 221 resilience tester.

The average thickness of the base material is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1.0 mm or more and 3.0 mm or less.

The Martens hardness of the base material is not particularly limited and can be appropriately selected depending on the purpose. A more preferable range of the Martens hardness of the substrate is 0.8 N/mm ² or more and 3.0 N/mm ² or less. By setting the Martens hardness of the base material to 0.8 N/mm ² or more and 3.0 N/mm ² or less, cracks in the surface layer of 10 μm or more can be suppressed, and cleaning failures are less likely to occur even after long-term use. . Further, since the base material has a Martens hardness of 0.8 N/mm ² or more, the base material is not too soft, and deformation due to vibrations due to axial vibration of the member to be cleaned (for example, an image carrier) is suppressed. The layer easily follows the deformation of the base material, prevents the occurrence of cracks, and improves cleanability.

A method for measuring the Martens hardness (HM) of the substrate is as follows. Martens hardness (HM) is based on ISO 14577, using Elionix's nanoindenter ENT-3100, indenting a Berkovich indenter with a load of 1000 μN for 10 seconds, holding it for 5 seconds, and removing it for 10 seconds at the same loading speed. . The measurement location is a position 100 μm from the tip ridgeline of the tip face of the blade.
As a method of measurement, as shown in FIG. A base material 622 is cut into a rectangular shape of 10 mm, and as shown in the perspective view of the base material in FIG. 11A and the front view of the base material in FIG. It can be fixed on the glass with an adhesive or double-sided tape, and the Martens hardness (HM) can be measured at a position 100 μm in the depth direction from the tip ridge 62c as a measurement position. On the other hand, the Martens hardness (HM) can be similarly measured even in a state in which a surface layer is formed on the lower surface of the substrate as shown in FIG. 11C. Alternatively, the Martens hardness (HM) can be measured by cutting the surface layer with a razor or the like to expose the tip surface of the substrate. Note that the Martens hardness (HM) of the surface layer 623 described below is obtained by cutting the substrate with the surface layer formed on the bottom surface of the substrate as shown in FIG. It is fixed on the glass with an adhesive or double-sided tape and measured by the above method.

-Surface layer-
In the cleaning blade of the present embodiment, the ridgeline portion 62c at the tip that abuts on the image bearing member is formed of a surface layer 623, and the surface layer 623 is formed of a curable composition described below (combined with an elastic member). not a mixed layer). The surface layer 623 may be formed on the contact portion and the lower surface of the substrate, and may also be formed on the blade tip surface 62a. In addition, the elastic member may contain a curable composition.

The surface layer 623 may cover the entire surface of the substrate, but is preferably formed over a region of at least 1 mm or more, preferably 1 mm or more and 7 mm or less in the surface direction from the contact portion to the bottom surface of the substrate. When the area is 7 mm or less, the flexibility of the elastic member is not hindered, and the followability to the photoreceptor is improved, resulting in improved cleaning performance.

The material of the surface layer 623 is not particularly limited and can be appropriately selected according to the purpose, but it is preferable that the Martens hardness of the cured product is higher than that of the base material. The surface layer 623 is made of a member having a hardness higher than that of the base material 622 of the elastic member 624 , so that the surface layer 623 is hard to deform and can suppress the tip ridge 62 c of the cleaning blade 62 from being turned over.

The method for curing the curable composition of the surface layer formed on the contact portion of the cleaning blade is not particularly limited and can be appropriately selected according to the purpose. be done.

The elastic work rate of the cleaning blade is preferably 60% or more and 90% or less. The elastic work rate is a characteristic value obtained as follows from the integrated stress at the time of measurement of Martens hardness. The Martens hardness is measured using a microhardness meter while pressing a Berkovich indenter with a constant force, for example, for 30 seconds, holding it for 5 seconds, and pulling it out with a constant force for 30 seconds.
Here, if the integrated stress when pushing the Berkovich indenter is Wplast, and the integrated stress when the test load is unloaded is Welast, the elastic power is a characteristic value defined by the formula Welast/Wplast×100 [%]. (See Figure 4). The higher the elastic power, the less the plastic deformation, that is, the higher the rubberiness. When the elastic power is 60% or more, the movement of the contact portion is not suppressed, and the abrasion resistance is improved.

--Curable composition--
The curable composition is a material in which monomers and oligomers are polymerized and cured by receiving energy such as light and heat to form a cured product (solid polymer). The energy source differs depending on the type of initiator and stimulus (electron beam) that generates active species (radicals, ions, acids, bases, etc.) that initiates polymerization. curing compositions and the like.

UV curable compositions and electron beam curable compositions use a photopolymerization initiator, and when irradiated with ultraviolet rays or electron beams, a curing reaction classified into one of radical polymerization, cationic polymerization, and anionic polymerization occurs. A cured product is produced by a polymerization reaction such as vinyl polymerization, vinyl copolymerization, ring-opening polymerization, or addition polymerization.
The thermosetting composition uses a thermal polymerization initiator and initiates a curing reaction by heating to produce a cured product through a polymerization reaction such as isocyanate, radical polymerization, epoxy ring-opening polymerization, and melamine condensation.

The cured product produced by such a reaction is not particularly limited and can be appropriately selected according to the purpose. Examples include acrylic resin, phenol resin, urethane resin, epoxy resin, silicone resin, amino resin, or Examples thereof include a resin composition having a polyethylene skeleton. However, it has excellent wear resistance, excellent compatibility and adhesion with the base material urethane rubber, and it is easy to adjust physical properties such as hardness and elastic work rate by controlling the NCO group and OH group. From this point of view, a polyurethane compound such as a urethane resin is preferable.

The urethane resin is not particularly limited and can be appropriately selected depending on the intended purpose, but a combination of a prepolymer having NCO groups at both ends and a curing agent (compound having _NH2 group or OH group) is preferable. The prepolymer having NCO groups at both ends is more preferably a prepolymer in which polyfunctional isocyanates are bound to both ends of PTMG (polytetramethylene ether glycol).

The polyfunctional isocyanate of the prepolymer is not particularly limited and can be appropriately selected depending on the purpose. ,5-diisocyanate (NDI), tetramethylxylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI) ), norbornene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), and the like. These may be used singly in combination with PTMG, or may be used after conversion into a nurate form or the like.

Examples of the curing agent include compounds such as diols, triols, diamines, and triamines that can react with the prepolymer. Curing agents include trimethylolpropane (TMP), diaminodiphenylmethane (DDM), and the like. These may be used individually by 1 type, and may use 2 or more types together.
The degree of polymerization of PTMG in the prepolymer is not particularly limited, and can be appropriately selected according to the purpose.

The surface layer in the present invention has a hardness gradient in which the hardness decreases from the surface toward the bottom surface of the substrate in the film thickness direction. Such a hardness gradient can be formed, for example, as follows. For the surface layer, the equivalent ratio of the curable composition (equivalent of NCO groups in the prepolymer/equivalent of _NH2 groups and OH groups in the curing agent) is designed to be higher than 1, and the surplus NCO groups are used for curing. The hardness can be increased by increasing the number of isocyanurate bonds in the composition and increasing the crosslink density. A uniform increase in isocyanurate linkages throughout the curable composition may result in an overall too hard and brittle composition. Therefore, in the present invention, the amount of isocyanurate bonds in the curable composition on the surface side of the surface layer is preferably greater than the amount of isocyanurate bonds on the bottom surface side of the substrate. By forming the surface layer in this way, it is possible to obtain a hardness gradient in which the hardness decreases from the surface toward the bottom surface of the substrate in the film thickness direction. The surface layer on the lower surface side of the base material has a hardness close to that of the soft base material, and the quality such as followability as a blade is stabilized. In order to increase the amount of isocyanurate bonds of the curable composition on the surface side in the surface layer, for example, after applying the curable composition to the substrate, under a high temperature and high humidity environment such as 45 ° C./90% RH It is possible to allow the surface layer to undergo more cyanuration than the lower surface side of the substrate by leaving the substrate to stand for several days to complete the reaction of the surplus NCO groups.

The siloxane-based compound in the surface layer can be appropriately selected depending on the purpose, but modified silicone oil is preferable. By using modified silicone oil, the friction coefficient of the blade is reduced, the friction force during sliding is reduced, the wear of the blade is suppressed, and the behavior of the blade tip during sliding is stabilized. . In addition, in the form of using a polyurethane-based compound, since the polyurethane-based compound is generally hard, the use of the modified silicone oil can promote the stabilization of the behavior of the tip of the blade.

Modified silicone oils include polyether-modified silicone oils, alkyl-modified silicone oils and the like, and commercially available products such as SH8400 (polyether-modified silicone oil manufactured by Dow Corning Toray Co., Ltd.) and FZ-2110 can be used. (polyether-modified silicone oil manufactured by Dow Corning Toray), SF8416 (manufactured by Dow Corning Toray, alkyl-modified silicone oil), SH3773M (polyether-modified silicone oil manufactured by Dow Corning Toray), X-22-4272 (manufactured by Shin-Etsu Silicone polyether-modified silicone oil) and the like.
The content of the siloxane-based compound in the surface layer is, for example, 3% by mass or more and 15% by mass or less, preferably 8% by mass or more and 15% by mass or less, more preferably 8% by mass or more and 10% by mass or less.

From the viewpoint of improving the effects of the present invention, the surface layer in the present invention has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction. It is preferable to have The measurement points of the Martens hardness HM are at least two points near the surface of the surface layer and the deepest part in the film thickness direction. The Martens hardness (HM) of the surface layer can be measured by the same method as the method for measuring the Martens hardness (HM) of the substrate. The "Martens hardness HM near the surface of the surface layer" is measured by pressing a Berkovich indenter with a load of 1 μN for 10 seconds, holding it for 5 seconds, and removing it with the same load for 10 seconds. Similarly, the "Martens hardness HM of the deepest part in the film thickness direction of the surface layer" is measured by pressing a Berkovich indenter with a load of 1000 μN for 10 seconds, holding it for 5 seconds, and removing it with the same load for 10 seconds. Also, the "Martens hardness HM at an intermediate portion" is measured by pressing a Berkovich indenter with a load of 50 μN for 10 seconds, holding it for 5 seconds, and removing it with the same load for 10 seconds.

The Martens hardness HM of the surface layer in the present invention is preferably 2.5 N/mm ² or more and 32.5 N/mm ² or less in the measured value at a load of 1 μN and the measured value at a load of 1000 μN, and 4.0 N/mm More preferably, it is ² or more and 21.0 N/mm ² or less. Specifically, the Martens hardness HM near the surface (load: 1 μN) of the surface layer in the present invention is preferably 7.5 N/mm ² or more and 32.5 N/mm ² or less, and 17.0 N/mm ² More preferably, it is 21.0 N/mm ² or more. In addition, the Martens hardness HM of the deepest portion (load: 1000 μN) in the film thickness direction of the surface layer in the present invention is preferably 2.5 N/mm ² or more and 9.5 N/mm ² or less, and 3.5 N/mm ² . More preferably, it is at least 5.0 N/mm ² or less. In addition, the Martens hardness HM of the intermediate portion (load: 50 μN) of the surface layer in the present invention is preferably 4.0 N/mm ² or more and 18.0 N/mm ² or less, and 7.0 N/mm 2 or more and 12.0 N/mm ² or more. It is more preferably 0 N/mm ² or less.
If the measured value at a load of 1 μN is less than 2.5 N/mm ² , the surface layer is likely to deform and the effect of the surface layer cannot be exhibited.
If the measured value at a load of 1000 μN is less than 2.5 N/mm ² , the surface layer is likely to deform, although not as much as the measured value at a load of 1 μN is less than 2.5 N/mm ² . The effect of the surface layer cannot be exhibited.
If the measured value at a load of 1 μN exceeds 32.5 N/mm ² , the hardness in the surface vicinity of the surface layer is high, and the quality of the blade such as followability is not stable.
If the measured value at a load of 1000 μN exceeds 32.5 N/mm ² , the surface layer as a whole becomes too hard and brittle.

Furthermore, from the viewpoint of improving the effects of the present invention, the surface layer in the present invention has a gradient in which the creep CIT measured using the nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction. The creep CIT is preferably 3.0 to 13.5% in the range from the vicinity of the surface (load: 1 μN) to the deepest portion in the film thickness direction (load: 1000 μN), and 5.0 to 12.5%. 0% is more preferred. Specifically, the creep CIT in the vicinity of the surface of the surface layer (load: 1 μN) in the present invention is preferably 9.5 to 13.5%, more preferably 9.5 to 12.0%. preferable. Further, the creep CIT at the deepest portion (load: 1000 μN) in the film thickness direction of the surface layer in the present invention is preferably 3.0 to 7.5%, more preferably 3.0 to 6.5%. preferable. Further, the creep CIT at the intermediate portion (load: 50 μN) of the surface layer in the present invention is preferably 6.0 to 11.0%, more preferably 6.0 to 9.5%.

<Development means>
The developing means is a means for developing an electrostatic latent image formed on the image carrier with toner to form a visible image.
The developing means comprises the toner.

<<Toner>>
The base colored particles of the toner used in the present invention comprise at least a binder resin, a chromatic colorant, and a release agent, and are etc.), but it is not limited to these manufacturing methods. The toner used in the present invention preferably has a low degree of circularity and a high content of fine powder in order to maintain cleanability over time. A method for producing such a toner includes a pulverization method. The manufacturing method and the materials, additives, and the like used in the manufacturing method are described below.
As an example of a pulverization system, a toner having a step of mechanically mixing raw materials containing at least a binder resin, a charge control agent and a colorant, a step of melt-kneading, a step of pulverizing, and a step of classifying. Manufacturing methods can be applied. Further, in order to improve the dispersibility of the colorant, the colorant may be mixed with other raw materials after masterbatch treatment, and then processed in the next step.

The mixing step of mechanically mixing may be performed under normal conditions using a normal mixer with rotating blades, and is not particularly limited. After the above mixing process is completed, the mixture is charged into a kneader and melt-kneaded. As the melt-kneader, a single-screw or twin-screw continuous kneader or a batch-type kneader using a roll mill can be used. Specific apparatuses for kneading the toner include a batch-type two-roll mixer, a Banbury mixer, and a continuous twin-screw extruder, such as a KTK type twin-screw extruder manufactured by Kobe Steel, Ltd., and a TEM type twin-screw extruder manufactured by Toshiba Machine Co., Ltd. Extruder, twin-screw extruder manufactured by KCK Co., Ltd., PCM type twin-screw extruder manufactured by Ikegai Iron Works Co., Ltd., KEX type twin-screw extruder manufactured by Kurimoto Iron Works Co., Ltd., continuous single-screw kneader, for example, co-kneader manufactured by BUSS Co., Ltd. etc. are preferably used. The melt-kneaded product obtained as described above is cooled and then pulverized. Pulverization is performed by coarse pulverization using, for example, a hammer mill or Rotoplex, and further pulverization by a fine pulverizer using a jet stream or mechanical pulverization. machine can be used. Pulverization is preferably carried out so that the average particle size is 3 to 15 μm. Further, the pulverized material is adjusted to a particle size of 2 to 7 μm by an air classifier or the like. Next, an external additive is externally added to the toner particles. By mixing and stirring the toner particles and the external additive using a mixer or the like, the external additive is pulverized and coated on the toner particle surfaces.
Although known binder resins can be used in this pulverized toner, it is preferable to use a polyester resin from the viewpoint of improving the dispersibility of the pigment and obtaining an image with a wider color reproduction range. Furthermore, a wide fixing temperature range can be ensured by using the crystalline polyester and the non-crystalline polyester, which are binder resins, and a release agent. Also, in order not to impair the glossiness, hot offset can be prevented by improving the dispersibility of the release agent.

- Binder resin -
The binder resin is not particularly limited and can be appropriately selected depending on the intended purpose. For example, a polyester resin can be suitably used as the binder resin.

--Polyester resin--
The polyester resin can be obtained by polycondensation of alcohol and carboxylic acid.

Examples of the alcohol include diols such as polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-butanediol. Etherified bisphenols such as 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene bisphenol A, saturated Alternatively, a divalent alcohol simple substance substituted with an unsaturated hydrocarbon group, other divalent alcohol simple substance, and the like can be mentioned.

Examples of the carboxylic acid include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, and malonic acid. , divalent organic acid monomers substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, acid anhydrides thereof, dimers of lower alkyl esters and linoleic acid, and other divalent and organic acid monomers.

Moreover, as the polyester resin, in addition to the above-described polymer composed of only the bifunctional monomer, a polymer containing a component composed of a trifunctional or higher polyfunctional monomer can also be used.

Trivalent or higher polyhydric alcohol monomers that are polyfunctional monomers include, for example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-salbitan, pentaerythritol, dipentaerythritol, Tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri methylolpropane, 1,3,5-trihydroxymethylbenzene, and the like.

Trivalent or higher polyvalent carboxylic acid monomers include, for example, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5, 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene carboxypropane, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, acid anhydrides thereof, and the like.

Also, a known binder resin can be used together with the polyester resin as the binder resin.
Examples of the binder resin include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and their substituted homopolymers; styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, and styrene. -vinyl toluene copolymer, styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer , styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-methyl chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl Methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-malein Acid copolymers, styrene-based copolymers such as styrene-maleic acid ester copolymers, and the like can be mentioned.
Furthermore, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, Aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc., and the above polyester resins may be mixed and used.

The toner used in the present invention may contain a crystalline resin in order to improve low-temperature fixability. As for the type, it is preferable to use a polyester resin. Crystalline polyesters are obtained as polycondensates of polyols and polycarboxylic acids, and the polyols are preferably aliphatic diols, specifically ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4 -butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,4-butenediol and the like, among which 1 ,4-butanediol, 1,6-hexanediol and 1,8-octanediol are preferred, and 1,6-hexanediol is more preferred. As the polycarboxylic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid and aliphatic carboxylic acids having 2 to 8 carbon atoms are preferable, but aliphatic carboxylic acids are more preferable in order to increase the degree of crystallinity. .

A crystalline resin (crystalline polyester) and an amorphous resin are distinguished by thermal characteristics. A crystalline resin refers to a resin that has a distinct endothermic peak, such as wax, in DSC measurements. On the other hand, a gentle curve based on the glass transition is observed in the amorphous resin.

--Release agent--
A known release agent can be used as the release agent for use in the present invention. Such waxes include, for example, polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long-chain hydrocarbons (paraffin wax, sazol wax, etc.); carbonyl group-containing waxes, and the like. Of these, carbonyl group-containing waxes are preferred.

Examples of carbonyl group-containing waxes include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1 , 18-octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitate, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenylamide, etc.); etc.); and dialkyl ketones (such as distearyl ketone).

The melting point of the release agent of the present invention is preferably 50 to 120°C, more preferably 60 to 90°C. The melt viscosity of the release agent is preferably 5 to 1000 cps, more preferably 10 to 100 cps as measured at a temperature 20° C. higher than the melting point.

--Colorant--
As the coloring agent of the present invention, all known dyes and pigments can be used. , ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), vulcan fast yellow ( 5G, R), tartrazine lake, quinoline yellow lake, anthrazane yellow BGL, isoindolinone yellow, red iron oxide, red lead, red lead, cadmium red, cadmium mercury red, antimony vermillion, permanent red 4R, para red , Phise Red, Parachlororthonitroaniline Red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fastlubin B, Brilliant Scarlet G, Risol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, rhodamine lake Y, alizarin lake, thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermillion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue lake, peacock blue lake, victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine blue, navy blue, anthraquinone blue, fast violet B, methyl violet lake, Cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green , titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

The colorant used in the present invention can also be used as a masterbatch compounded with a resin. A resin selected from the binder resins described above is used for the production of the masterbatch or the resin kneaded together with the masterbatch.
This masterbatch can be obtained by mixing and kneading a masterbatch resin and a colorant by applying a high shearing force. At this time, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, in which an aqueous paste containing colorant water is mixed and kneaded with a resin and an organic solvent, the colorant is transferred to the resin side, and the water and organic solvent components are removed to form a wet cake of the colorant. Since it can be used as it is, there is no need to dry it, and it is preferably used. For mixing and kneading, a high-shear dispersing device such as a three-roll mill is preferably used.

--Charge control agent--
In the present invention, all known charge control agents can be used in order to impart appropriate charging properties to the toner. , rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus elements or compounds, tungsten elements or compounds, fluorine-based surfactants, metal salicylates and salicylic acid Metal salts of derivatives and the like. Specifically, nigrosine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid-based metal complex E-82, salicylic acid-based metal complex E- 84, E-89 of phenolic condensate (above, manufactured by Orient Chemical Industry Co., Ltd.), TP-302, TP-415 of quaternary ammonium salt molybdenum complex and TN-105 of zirconium compound (above, Hodogaya Chemical Industry Co., Ltd. ), quaternary ammonium salt copy charge PSYVP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEGVP2036, copy charge NXVP434 (manufactured by Hoechst), LRA-901, boron complex LR-147 (manufactured by Nihon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymeric compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

Preferably, the compound is a crystalline compound, and more preferably one that is easily pulverized into fine particles of 1 μm by stress or the like. These charge control agent particles can also be incorporated in advance inside the resin particles containing the colorant to reinforce the chargeability. The amount of the charge control agent particles to be stirred together with the resin particles containing the colorant is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1 part by weight, with respect to 100 parts by weight of the resin particles containing the colorant. parts, most preferably 0.1 to 0.5 parts by weight.

--external additives--
In addition to fine particles having an average particle diameter of 0.04 to 0.30 μm, inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability, and chargeability of the colored particles obtained in the present invention. can be used. In particular, hydrophobic silica and/or hydrophobic titanium oxide are preferred. The primary particle diameter of the inorganic fine particles is preferably 5 mμ to 2 μm, particularly preferably 5 mμ to 500 mμ. Also, the specific surface area by the BET method is preferably 20 to 500 m ² /g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by mass, particularly preferably 0.01 to 2.0% by mass, of the toner.

Specific examples of other inorganic fine particles include alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, Chromium oxide, cerium oxide, pengal oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like can be mentioned.

In addition, polymer-based fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, methacrylic acid ester, acrylic acid ester copolymer, silicone, benzoguanamine, polycondensation such as nylon, thermosetting resin and polymer particles according to

Such a fluidizing agent can be subjected to surface treatment to increase hydrophobicity and prevent deterioration of fluidity and charging characteristics even under high humidity. Examples of preferred surface treatment agents include silane coupling agents, silylating agents, silane coupling agents having alkyl fluoride groups, organic titanate-based coupling agents, aluminum-based coupling agents, silicone oils, and modified silicone oils. .

Examples of cleaning improvers for removing the developer remaining on the image carrier or intermediate transfer member after transfer include zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, polymethyl methacrylate fine particles, and polystyrene fine particles. polymer fine particles produced by soap-free emulsion polymerization such as The fine polymer particles have a relatively narrow particle size distribution, and preferably have an average particle size of 0.01 to 1 μm.

In the present invention, it is preferable to use the above-described masterbatch colorant particles as the colorant, whereby the colorant can be uniformly dispersed efficiently.

-- Circularity, 2 μm or less fine powder content, 2 μm or less fine powder circularity --
To achieve the object of the present invention, the toner preferably has a circularity of less than 0.950, more preferably less than 0.945, and even more preferably less than 0.940. The surface layer of the cleaning blade used in the present invention has a very high hardness and a low μ (low coefficient of friction), so that it has high cleaning performance and excellent wear resistance, but as shown in FIG. Since the nip width of the abutting portion of the blade 62 is widened and the peak pressure is lowered, the circularity of the toner is less than 0.950 so that it is difficult for the toner to enter the nip portion and the cleaning performance can be maintained. When the circularity of the toner is 0.950 or more, the nip width of the contact portion of the cleaning blade widens over time and the peak pressure decreases, so that the toner easily enters the nip portion and slips through the blade, resulting in poor cleaning. Because it becomes easy, it is inferior in durability.
The lower limit of the circularity is not particularly limited and can be appropriately selected depending on the purpose. For example, it may be 0.900 or 0.910.

In order to achieve the object of the present invention, it is preferable that the content of fine particles of 2 μm or less in the toner is 20% by number or more and 60% by number or less. 2 μm or less When the fine powder content is 20% or more and 60% or less by number, as shown in FIG. is constantly replaced while circulating due to the deformation of the blade (shaped to protrude the jaw), so contamination such as filming on the photoreceptor can be suppressed. Due to the apparent dam layer of this fine powder, normal size toner is repelled without entering the vicinity of the nip portion. If the fine powder content of 2 μm or less is less than 20% by number, an apparent dam layer cannot be formed, resulting in a decrease in cleanability. As a result, contamination such as filming on the photoreceptor occurs.

In order to achieve the object of the present invention, it is preferable that the circularity of fine powder of 2 μm or less of the toner is 0.950 or more and 0.985 or less. When the circularity of the fine powder of 2 μm or less is 0.950 or more and 0.985 or less, the circulation of the fine powder is more likely to occur, so that contamination such as filming on the photoreceptor can be further suppressed.

The circularity, the fine powder content of 2 μm or less, and the circularity of fine powder of 2 μm or less are determined by a flow type particle image analyzer FPIA-3000.
0.1-0.5 ml of alkylbenzene sulfonate as a dispersant is added to 100-150 ml of water using a container from which impure solids have been previously removed, and then about 0.1-0.5 g of toner is added. The suspension in which the sample is dispersed is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the shape and distribution of the toner are measured with the apparatus at a dispersion concentration of 3,000 to 10,000 particles/μl. A fine powder content of 2 μm or less and a circularity of fine powder of 2 μm or less are obtained.

<Image carrier>
The shape, structure, size, material, etc. of the image carrier are not particularly limited, and can be appropriately selected according to the purpose.
The shape of the image bearing member is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a drum shape and a belt shape.
The material of the image carrier is not particularly limited and can be appropriately selected depending on the intended purpose. is mentioned.
The image bearing member is rotated at a high linear velocity of 600 mm/sec or higher to enable high-speed image formation.

<Other means>
The other means are not particularly limited and can be appropriately selected according to the purpose, and examples thereof include charging means, exposure means, transfer means, fixing means, and auxiliary cleaning means.
The auxiliary cleaning means has a mechanism for applying a lubricant to the surface of the image carrier.

The process cartridge is a device (unit) detachably provided in the image forming apparatus.

The image forming method includes, for example, a developing step and a cleaning step, and further includes other steps appropriately selected as necessary.
The image forming method can be suitably performed by the image forming apparatus, the charging step can be performed by the charging means, the exposure step can be performed by the exposure means, and the developing step can be performed by the The transfer process can be performed by the transfer means, the fixing process can be performed by the fixing means, the cleaning process can be performed by the cleaning means, and the other The process can be performed by the other means described above.

An electrophotographic printer (hereinafter simply referred to as printer 500) as an image forming apparatus to which the present invention is applied will be described below. First, the basic configuration of the printer 500 according to this embodiment will be described.

FIG. 5 is a schematic configuration diagram showing the printer 500. As shown in FIG. The printer 500 has four image forming units 1Y, C, M and K for yellow, magenta, cyan and black (hereinafter referred to as Y, C, M and K). They use Y, C, M, and K toners of different colors as image forming substances for forming images, but otherwise have the same configuration.

A transfer unit 60 having an intermediate transfer belt 14 as an intermediate transfer member is arranged above the four image forming units 1 . Toner images of respective colors formed on the surfaces of the photoreceptors 3Y, C, M, and K provided in the respective image forming units 1Y, C, M, and K, which will be detailed later, are superimposed on the surface of the intermediate transfer belt . It is a configuration to be transcribed.

An optical writing unit 40 is arranged below the four image forming units 1 . The optical writing unit 40, which is a latent image forming means, irradiates the photoreceptors 3Y, C, M, K of the image forming units 1Y, C, M, K with laser light L emitted based on image information. As a result, electrostatic latent images for Y, C, M, and K are formed on the photoreceptors 3Y, C, M, and K, respectively. The optical writing unit 40 deflects the laser light L emitted from the light source by a polygon mirror 41 rotated by a motor, and writes the light onto the photoreceptors 3Y, C, M, and K via a plurality of optical lenses and mirrors. It irradiates to Instead of such a configuration, it is also possible to employ a device that performs optical scanning using an LED array.

Below the optical writing unit 40, a first paper cassette 151 and a second paper cassette 152 are arranged so as to overlap vertically. In each of these paper feed cassettes, a plurality of sheets of transfer paper P, which are recording media, are accommodated in a paper bundle state. The second paper feed rollers 152a are in contact with each other. When the first paper feed roller 151a is driven to rotate counterclockwise in the figure by the drive means, the uppermost transfer paper P in the first paper feed cassette 151 extends vertically in the right side of the cassette in the figure. The sheets are discharged toward the paper feed path 153 arranged so as to be present. Further, when the second paper feed roller 152a is driven to rotate counterclockwise in FIG. be done.

A plurality of transport roller pairs 154 are arranged in the paper feed path 153 . The transfer paper P fed into the paper feed path 153 is conveyed from the lower side to the upper side in FIG.

A registration roller pair 55 is arranged at the downstream end of the paper feed path 153 in the transport direction. As soon as the registration roller pair 55 sandwiches the transfer paper P sent from the conveying roller pair 154 between the rollers, the rotation of both rollers is temporarily stopped. Then, the transfer paper P is fed toward a secondary transfer nip, which will be described later, at an appropriate timing.

FIG. 6 is a configuration diagram showing a schematic configuration of one of the four image forming units 1. As shown in FIG.
As shown in FIG. 6, the image forming unit 1 includes a drum-shaped photosensitive member 3 as an image carrier. Although the photoreceptor 3 has a drum-like shape, it may have a sheet-like shape or an endless belt-like shape.

Around the photoreceptor 3, a charging roller 4, a developing device 5, a primary transfer roller 7, a cleaning device 6, a lubricant coating device 10, a static elimination lamp, and the like are arranged. The charging roller 4 is a charging member included in a charging device as charging means, and the developing device 5 is a developing means for converting the latent image formed on the surface of the photoreceptor 3 into a toner image. The primary transfer roller 7 is a primary transfer member provided in a primary transfer device as primary transfer means for transferring the toner image on the surface of the photoreceptor 3 to the intermediate transfer belt 14 . The cleaning device 6 is cleaning means for cleaning toner remaining on the photoreceptor 3 after the toner image has been transferred to the intermediate transfer belt 14 . The lubricant applicator 10 is a lubricant applicator that applies a lubricant to the surface of the photoreceptor 3 after being cleaned by the cleaning device 6 . The static elimination lamp is static elimination means for eliminating the surface potential of the photoreceptor 3 after cleaning.

The charging roller 4 is arranged in a non-contact manner with a predetermined distance from the photoreceptor 3, and charges the photoreceptor 3 to a predetermined polarity and a predetermined potential. The surface of the photoreceptor 3 uniformly charged by the charging roller 4 is irradiated with laser light L from an optical writing unit 40, which is a latent image forming means, based on image information to form an electrostatic latent image.

The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to the developing roller 51 from a power source. A supply screw 52 and an agitation screw 53 are provided in the casing of the developing device 5 for agitating the developer contained in the casing while transporting the developer in opposite directions. A doctor 54 for regulating the developer carried on the developing roller 51 is also provided. The toner in the developer agitated and conveyed by the two screws of the supply screw 52 and the agitation screw 53 is charged to a predetermined polarity. The developer is scooped up onto the surface of the developing roller 51 , the scooped up developer is regulated by the doctor 54 , and the toner adheres to the latent image on the photoreceptor 3 in the developing area facing the photoreceptor 3 . .

The cleaning device 6 has a fur brush 101, a cleaning blade 62, and the like. The cleaning blade 62 is in contact with the photoreceptor 3 in a direction counter to the surface moving direction of the photoreceptor 3 . The cleaning blade 62 is the cleaning blade of the present invention. The lubricant application device 10 includes a solid lubricant 103, a lubricant pressure spring 103a, and the like, and uses a fur brush 101 as an application brush for applying the solid lubricant 103 onto the photosensitive member 3. FIG. A solid lubricant 103 is held by a bracket 103b and is pressed toward the fur brush 101 by a lubricant pressurizing spring 103a. Then, the solid lubricant 103 is scraped by the fur brush 101 that rotates in the rotation direction with respect to the rotation direction of the photoreceptor 3 and the lubricant is applied onto the photoreceptor 3 . It is preferable that the coefficient of friction of the surface of the photoreceptor 3 is maintained at 0.2 or less during non-image formation by applying a lubricant to the photoreceptor.

The charging device of this embodiment is of a non-contact, close arrangement type in which the charging roller 4 is placed close to the photoreceptor 3. Examples of charging devices include corotrons, scorotrons, and solid state chargers. A known configuration can be used. Among these charging methods, the contact charging method or the non-contact close-positioning method is particularly preferable, and has advantages such as high charging efficiency, low ozone generation amount, and possibility of miniaturization of the apparatus.

The light source of the laser light L of the optical writing unit 40 and the light source such as the static elimination lamp include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LED), semiconductor lasers (LD), electroluminescence (EL), ) can be used.
Moreover, various filters such as a sharp cut filter, a bandpass filter, a near-infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used in order to irradiate only light in a desired wavelength range.
Among these light sources, light-emitting diodes and semiconductor lasers are favorably used because they have high irradiation energy and long-wavelength light of 600 to 800 nm.

A transfer unit 60, which is a transfer means, includes an intermediate transfer belt 14, a belt cleaning unit 162, a first bracket 63, a second bracket 64, and the like. It also has four primary transfer rollers 7Y, C, M, K, a secondary transfer backup roller 66, a drive roller 67, an auxiliary roller 68, a tension roller 69, and the like. The intermediate transfer belt 14 is endlessly moved counterclockwise in the figure by the rotation of the drive roller 67 while being stretched around these eight roller members. The four primary transfer rollers 7Y, C, M, and K sandwich the endlessly moved intermediate transfer belt 14 between the photoreceptors 3Y, C, M, and K to form primary transfer nips. . Then, a transfer bias having a polarity opposite to that of the toner (for example, plus) is applied to the back surface of the intermediate transfer belt 14 (the inner circumferential surface of the loop). The intermediate transfer belt 14 passes through the primary transfer nips for Y, C, M, and K successively as it moves endlessly. Y, C, M, and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 14 .

The secondary transfer backup roller 66 sandwiches the intermediate transfer belt 14 between itself and a secondary transfer roller 70 arranged outside the loop of the intermediate transfer belt 14 to form a secondary transfer nip. The registration roller pair 55 described above feeds the transfer paper P sandwiched between the rollers toward the secondary transfer nip at a timing that can be synchronized with the four-color toner image on the intermediate transfer belt 14 . The four-color toner image on the intermediate transfer belt 14 is affected by the secondary transfer electric field formed between the secondary transfer roller 70 to which the secondary transfer bias is applied and the secondary transfer backup roller 66 and the nip pressure. , are collectively secondarily transferred to the transfer paper P in the secondary transfer nip. Combined with the white color of the transfer paper P, a full-color toner image is formed.

Transfer residual toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 14 after passing through the secondary transfer nip. It is cleaned by belt cleaning unit 162 . In the belt cleaning unit 162, a belt cleaning blade 162a is brought into contact with the front surface of the intermediate transfer belt 14, thereby scraping and removing transfer residual toner on the intermediate transfer belt 14. FIG.

The first bracket 63 of the transfer unit 60 swings at a predetermined rotation angle about the rotation axis of the auxiliary roller 68 as the solenoid is turned on and off. When forming a monochrome image, the printer 500 slightly rotates the first bracket 63 counterclockwise in the drawing by driving the above-described solenoid. By this rotation, the primary transfer rollers 7Y, C, and M for Y, C, and M are revolved counterclockwise in the drawing about the rotation axis of the auxiliary roller 68, thereby rotating the intermediate transfer belt 14 to Y, C, and M. It is separated from the photoconductors 3Y, C, and M for M. Of the four image forming units 1Y, C, M, and K, only the image forming unit 1K for K is driven to form a monochrome image. As a result, it is possible to avoid wasting of each member constituting the image forming unit 1 caused by driving the image forming unit 1 for Y, C, and M unnecessarily during monochrome image formation.

A fixing unit 80 is arranged above the secondary transfer nip in the figure. The fixing unit 80 includes a pressure heating roller 81 containing a heat source such as a halogen lamp, and a fixing belt unit 82 . The fixing belt unit 82 has a fixing belt 84 as a fixing member, a heating roller 83 including a heat source such as a halogen lamp, a tension roller 85, a driving roller 86, a temperature sensor, and the like. The endless fixing belt 84 is stretched by a heating roller 83, a tension roller 85 and a drive roller 86, and is endlessly moved counterclockwise in the figure. In the course of this endless movement, the fixing belt 84 is heated from the back side by the heating roller 83 . A pressurizing heating roller 81 rotated clockwise in the drawing abuts from the front surface side on the portion where the fixing belt 84 heated in this way is wound around the heating roller 83 . As a result, a fixing nip is formed in which the pressure heating roller 81 and the fixing belt 84 are brought into contact with each other.

A temperature sensor is arranged outside the loop of the fixing belt 84 so as to face the front surface of the fixing belt 84 with a predetermined gap therebetween. to detect. This detection result is sent to the fixing power supply circuit. The fixing power supply circuit controls on/off of power supply to the heat source included in the heating roller 83 and the heat source included in the pressure heating roller 81 based on the detection result of the temperature sensor.

After passing through the secondary transfer nip, the transfer paper P is separated from the intermediate transfer belt 14 and sent into the fixing unit 80 . In the process of being sandwiched between the fixing nip in the fixing unit 80 and conveyed from the lower side to the upper side in the figure, the full-color toner image is fixed on the transfer paper P by being heated and pressed by the fixing belt 84 . be.

The transfer paper P that has undergone the fixing process in this manner passes between the rollers of the paper discharge roller pair 87, and is then discharged outside the machine. A stack section 88 is formed on the upper surface of the housing of the main body of the printer 500 , and the transfer papers P discharged outside the machine by the pair of discharge rollers 87 are sequentially stacked on this stack section 88 .

Above the transfer unit 60, four toner cartridges 100Y, 100C, 100M and 100K containing Y, C, M and K toners are arranged. The Y, C, M, and K toners in the toner cartridges 100Y, C, M, and K are appropriately supplied to the developing devices 5Y, C, M, and K of the image forming units 1Y, C, M, and K. These toner cartridges 100Y, 100C, 100M and 100K can be attached to and detached from the printer body independently of the image forming units 1Y, 100C, 100M and 100K.

Next, an image forming operation in printer 500 will be described.
When a print execution signal is received from an operation unit or the like, predetermined voltages or currents are sequentially applied to the charging roller 4 and the developing roller 51 at predetermined timings. Similarly, predetermined voltages or currents are sequentially applied at predetermined timings to the optical writing unit 40 and the light source such as the charge removal lamp. In synchronism with this, the photoreceptor 3 is rotationally driven in the direction of the arrow in the drawing by a photoreceptor driving motor as a driving means.

When the photoreceptor 3 rotates in the direction of the arrow in the drawing, the surface of the photoreceptor 3 is first uniformly charged to a predetermined potential by the charging roller 4 . Then, the photoreceptor 3 is irradiated with a laser beam L corresponding to image information from the optical writing unit 40, and the portion irradiated with the laser beam L on the surface of the photoreceptor 3 is discharged to form an electrostatic latent image. .

The surface of the photoreceptor 3 on which the electrostatic latent image is formed is rubbed by a magnetic brush of developer formed on the developing roller 51 at the portion facing the developing device 5 . At this time, the negatively charged toner on the developing roller 51 is moved to the electrostatic latent image side by a predetermined developing bias applied to the developing roller 51 and is formed into a toner image (developed). A similar image forming process is executed in each image forming unit 1, and a toner image of each color is formed on the surface of each photoreceptor 3Y, C, M, K of each image forming unit 1Y, C, M, K. .

Thus, in the printer 500 , the electrostatic latent image formed on the photoreceptor 3 is reversely developed by the developing device 5 with negatively charged toner. In the present embodiment, an example using an N/P (negative/positive: toner adheres to low potential) non-contact charging roller system has been described, but the present invention is not limited to this.

The toner images of respective colors formed on the surfaces of the photoreceptors 3Y, C, M, and K are primary-transferred sequentially so as to overlap on the surface of the intermediate transfer belt . Thereby, a four-color toner image is formed on the intermediate transfer belt 14 .

The four-color toner image formed on the intermediate transfer belt 14 is fed from the first paper feed cassette 151 or the second paper feed cassette 152, passes between the rollers of the registration roller pair 55, and is fed to the secondary transfer nip. is transferred to the transfer paper P. At this time, the transfer paper P is temporarily stopped while sandwiched between the pair of registration rollers 55, and is supplied to the secondary transfer nip in synchronization with the leading edge of the image on the intermediate transfer belt 14. FIG. The transfer paper P onto which the toner image has been transferred is separated from the intermediate transfer belt 14 and conveyed to the fixing unit 80 . When the transfer paper P with the toner image transferred passes through the fixing unit 80, the toner image is fixed on the transfer paper P by the action of heat and pressure. 500 is ejected to the outside of the device and stacked in the stacking section 88 .

On the other hand, the belt cleaning unit 162 removes transfer residual toner on the surface of the intermediate transfer belt 14 from which the toner image has been transferred onto the transfer paper P at the secondary transfer nip.

On the surface of the photoreceptor 3 from which the toner images of each color have been transferred to the intermediate transfer belt 14 at the primary transfer nip, residual toner after transfer is removed by the cleaning device 6, and lubricant is applied by the lubricant applying device 10. After that, the charge is removed by the charge removal lamp.

As shown in FIG. 6, the image forming unit 1 of the printer 500 includes a photoreceptor 3, and a charging roller 4, a developing device 5, a cleaning device 6, a lubricant coating device 10, etc. as processing means, which are housed in a frame 2. . The image forming unit 1 is integrally detachable from the main body of the printer 500 as a process cartridge. In the printer 500, the image forming unit 1 integrally replaces the photoreceptor 3 as a process cartridge and the process means. A configuration may be adopted in which a unit such as the agent coating device 10 is replaced with a new one.

Examples of the present invention will be described below, but the present invention is not limited to the following examples. "Parts" means "mass parts" unless otherwise specified. "%" represents "% by mass" unless otherwise specified.

<Base material>
As the base material of the elastic member, urethane rubber having the following JIS-A hardness, 23° C. impact resilience, and Martens hardness (HM) was produced by centrifugal molding.
JIS-A hardness: 75°
23°C impact resilience: 45%
Martens hardness (HM): 0.9 N/mm ²
The measurement method is shown below.

<< JIS-A hardness of base material >>
The JIS-A hardness of the lower surface side of the base material of the elastic member was measured according to JIS K6253 (at 23° C.) using a Micro Rubber Hardness Tester MD-1 manufactured by Kobunshi Keiki Co., Ltd.

<<Rebound resilience of base material>>
The modulus of impact resilience of the base material of the elastic member was measured at 23° C. by Toyo Seiki Seisakusho No. It was measured according to JIS K6255 using a 221 resilience tester. The sample used was obtained by stacking sheets with a thickness of 2 mm so as to have a thickness of 4 mm or more.

<<Martens hardness of base material>>
The Martens hardness (HM) of the substrate was measured according to the method described above.

<Surface layer formation>
Materials used in the curable composition for forming the surface layer are shown below.
-Isocyanate-
・ MDI (4,4'-diphenylmethane diisocyanate): "Millionate MT" manufactured by Tosoh
・ Hydrogenated MDI (dicyclohexylmethane 4,4′-diisocyanate): manufactured by Tokyo Chemical Industry ・ TDI (2,4-tolylene diisocyanate): manufactured by Tosoh “Coronate T-100”
- Polyol -
· PTMG (polytetramethylene ether glycol): Mitsubishi Chemical "PTMG1000", "PTMG2000", "PTMG3000"
-Curing agent-
・ DDM (4,4′-diaminodiphenylmethane): manufactured by Tokyo Chemical Industry Co., Ltd. ・ TMP (trimethylolpropane): manufactured by Mitsubishi Gas Chemical - Catalyst -
・ Dioctyl tin dilaurate: Nitto Kasei “Neostan U-810”
-Siloxane compound-
・SH8400: Polyether-modified silicone oil manufactured by Dow Corning Toray ・FZ-2110: Polyether-modified silicone oil manufactured by Dow Corning Toray ・SF8416: Alkyl-modified silicone oil manufactured by Dow Corning Toray-NCO group prepolymer at both ends Synthesis-
As shown in Table 1 below, an isocyanate and a polyol were mixed so as to obtain the desired NCO%, and the mixture was stirred at 80° C. for 180 minutes under a nitrogen purge to react. 4 was prepared.

-Preparation of curable composition-
The above _prepolymers 1 to 4, curing agent, catalyst, The siloxane-based compound was mixed at room temperature for 3 minutes (parts by weight) and sufficiently defoamed. A curable composition was thus prepared.
Among the curing agents, DDM and TMP were diluted with MEK (methyl ethyl ketone) so as to have a solid content of 40% and a solid content of 10%, respectively.

<Toner preparation example>
Next, specific production examples of toner used for evaluation will be described. The toner used in the present invention is not limited to these examples.
[toner]
<<Production of Toner 1>>
Constituent material of toner 1
Binder resin: polyester resin (1/2 outflow start temperature: 106°C) 100 parts Release agent: carnauba wax 5 parts Coloring: carbon black 8 parts Charge control agent: salicylic acid derivative zinc salt 3 parts

After thoroughly mixing the constituent materials of toner 1 with a blender, the mixture was melted and kneaded with a twin-screw extruder heated to 100 to 110.degree. The kneaded product was allowed to cool, coarsely pulverized with a cutter mill, pulverized with a fine pulverizer using a jet stream, and then with an air classifier to obtain colored matrix particles 1.
Furthermore, to 100 parts of the base colored particles 1, 0.5 parts of hydrophobic silica having an average particle diameter of 20 nm, 0.5 parts of titanium oxide fine powder having an average particle diameter of 15 nm (isobutyltrimethoxysilane treatment), and an average particle diameter of 1.0 part of hydrophobic silica having a diameter of 120 nm was mixed with a Henschel mixer to obtain Toner 1.

<<Production of Toners 2 to 9>>
Toners 2 to 9 were obtained in the same manner as for Toner 1, except that the pulverization and classification conditions were changed so that toners having the physical properties shown in Table 3 were obtained.

<<Production of Toner 10>>
[Synthesis of polyester 1]
235 parts of bisphenol A ethylene oxide 2 mol adduct, 525 parts bisphenol A propylene oxide 3 mol adduct, 205 parts terephthalic acid, 47 parts adipic acid and dibutyl are placed in a reaction vessel equipped with a condenser, stirrer and nitrogen inlet. Add 2 parts of tin oxide, react at normal pressure of 230° C. for 8 hours, and further react at reduced pressure of 10 to 15 mmHg for 5 hours. After reacting for some time, [Polyester 1] was obtained. [Polyester 1] had a number average molecular weight of 2,600, a weight average molecular weight of 6,900, a Tg of 44°C, and an acid value of 26.

[Synthesis of prepolymer A]
682 parts of bisphenol A ethylene oxide 2 mol adduct, 81 parts of bisphenol A propylene oxide 2 mol adduct, 283 parts of terephthalic acid, and 22 parts of trimellitic anhydride were placed in a reaction vessel equipped with a condenser, stirrer and nitrogen inlet tube. and 2 parts of dibutyltin oxide were added, reacted at normal pressure of 230° C. for 8 hours, and further reacted under reduced pressure of 10 to 15 mmHg for 5 hours to obtain [intermediate polyester 1]. [Intermediate polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, a Tg of 55°C, an acid value of 0.5, and a hydroxyl value of 49.

Next, 411 parts of [intermediate polyester 1], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube and reacted at 100° C. for 5 hours, Polymer A] was obtained.

[Preparation of Masterbatch 1]
Carbon black (Regal 400R manufactured by Cabot Corporation): 40 parts, binder resin: polyester resin (Sanyo Kasei RS-801, acid value: 10, Mw: 20000, Tg: 64°C): 60 parts, and water: 30 parts were mixed in a Henschel mixer. , to obtain a mixture in which water was impregnated in pigment aggregates. The mixture was kneaded for 45 minutes with two rolls set at a roll surface temperature of 130° C. and pulverized to a size of 1 mm with a pulverizer to obtain [Masterbatch 1].

[Preparation of pigment/wax dispersion liquid 1 (oil phase)]
545 parts of [Polyester 1], 181 parts of paraffin wax, and 1450 parts of ethyl acetate were charged into a container equipped with a stirring rod and a thermometer, heated to 80°C while stirring, and maintained at 80°C for 5 hours. Cooled to 30° C. in 1 hour. Next, 500 parts of [masterbatch 1] and 100 parts of ethyl acetate were charged into a container and mixed for 1 hour to obtain [raw material solution 1].

[Raw material solution 1] 1,500 parts was transferred to a container, and a bead mill (Ultra Viscomill, manufactured by Aimex Co., Ltd.) was used to feed the liquid at a rate of 1 kg/hr, a disk peripheral speed of 6 m/sec, and 80% by volume of 0.5 mm zirconia beads. Carbon black and WAX were dispersed under conditions of filling and three passes. Then, 425 parts and 230 parts of [Polyester 1] were added, and one pass was carried out with the bead mill under the above conditions to obtain [Pigment/WAX Dispersion 1]. [Pigment/wax dispersion liquid 1] was added and adjusted so that the solid content concentration (130° C., 30 minutes) was 50%.

[Aqueous phase preparation process]
970 parts of ion-exchanged water, 40 parts of a 25% aqueous dispersion of organic resin fine particles for dispersion stabilization (styrene-methacrylic acid-butyl acrylate-methacrylate ethylene oxide adduct sulfate ester sodium salt copolymer), dodecyl diphenyl ether 140 parts of a 48.5% aqueous solution of sodium disulfonate (ELEMINOL MON-7: manufactured by Sanyo Chemical Industries) and 90 parts were mixed and stirred to obtain a milky white liquid. This is referred to as [aqueous phase 1].

[Emulsification process]
975 parts of [pigment/wax dispersion liquid 1] and 2.6 parts of isophoronediamine as an amine were mixed at 5,000 rpm for 1 minute with a TK homomixer (manufactured by Tokushu Kika), and then [prepolymer A] 88 After mixing for 1 minute at 5,000 rpm with a TK homomixer (manufactured by Tokushu Kika), 1200 parts of [aqueous phase 1] are added, and the TK homomixer is rotated at 8,000 rpm for 20 minutes. By mixing, [Emulsified slurry 1] was obtained.

[Solvent removal process]
[Emulsified slurry 1] was put into a container equipped with a stirrer and a thermometer, and the solvent was removed at 30° C. for 8 hours to obtain [dispersed slurry 1].

[Washing/drying process]
After filtering 100 parts of [dispersion slurry 1] under reduced pressure,
(1): 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (12,000 rpm for 10 minutes) and then filtered. The filtrate at this time was milky white.
(2): 900 parts of ion-exchanged water was added to the filter cake of (1), ultrasonically vibrated, mixed with a TK homomixer (12,000 rpm for 30 minutes), and filtered under reduced pressure. This operation was repeated until the electrical conductivity of the reslurry liquid was 10 μC/cm or less.
(3): 10% hydrochloric acid was added to the reslurry liquid of (2) so that the pH thereof became 4, and the mixture was stirred with a three-one motor for 30 minutes and then filtered.
(4): 100 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (12,000 rpm for 10 minutes) and then filtered. This operation was repeated until the electrical conductivity of the reslurry liquid was 10 μC/cm or less to obtain [filter cake 1].

[Filtration cake 1] was dried at 42° C. for 48 hours in a circulating air dryer and sieved through a 75 μm mesh to obtain [Toner base 1]. The circularity was 0.973 and the volume average particle diameter (Dv) was 6.2 μm.

Then, 100 parts of this [toner base 1], 1.0 part of hydrophobic silica having an average particle diameter of 20 nm as an external additive, and 0.5 part of titanium oxide fine powder having an average particle diameter of 15 nm (isobutyltrimethoxysilane treatment). , and 1.5 parts of hydrophobic silica having an average particle size of 120 nm are mixed for 30 seconds at a peripheral speed of 30 m / second using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) and rested for 1 minute. After performing 5 cycles, [Toner 10] was obtained by sieving with a mesh having an opening of 35 μm.

<Circularity, 2 μm or less fine powder content, 2 μm or less fine powder circularity>
Circularity (average circularity), fine powder content of 2 μm or less, and fine powder circularity of 2 μm or less were determined by a flow type particle image analyzer FPIA-3000.
0.1 to 0.5 ml of alkylbenzene sulfonate as a dispersant was added to 100 to 150 ml of water using a container from which impure solids had been previously removed, and then about 0.1 to 0.5 g of toner was added. The suspension in which the sample was dispersed was subjected to a dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the shape and distribution of the toner were measured with the apparatus at a dispersion liquid concentration of 3000 to 10000 particles/μl.

<Volume average particle size (Dv)>
The volume average particle diameter (Dv) of the toner is measured using a particle size analyzer (“Multisizer III”, manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm, and analyzed with analysis software (Beckman Coulter Multisizer 3 Version 3.51). did Specifically, 0.5 ml of a 10% surfactant (alkylbenzene sulfonate Neogen SC-A; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to a 100 ml glass beaker, 0.5 g of each toner was added, and the mixture was stirred with a microspatula. Then 80 ml of ion-exchanged water was added. The resulting dispersion was subjected to dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II manufactured by Honda Denshi Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter) as a measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the device was 8±2%.

Table 3 shows the results of the measurement as described above.

<Carrier>
Next, a specific production example of the carrier used for evaluation will be described. Carriers used in the present invention are not limited to these examples.
Acrylic resin solution (solid content 50% by mass) 21.0 parts Guanamine solution (solid content 70% by mass) 6.4 parts Alumina particles [0.3 μm, specific resistance 1014 (Ω cm)] 7.6 parts Silicone resin solution 65.0 parts [Solid content 23% by mass (SR2410: manufactured by Dow Corning Toray Silicone Co., Ltd.)]
Aminosilane 1.0 part [Solid content 100% by mass (SH6020: manufactured by Dow Corning Toray Silicone Co., Ltd.)]
60 parts of toluene and 60 parts of butyl cellosolve were dispersed in a homomixer for 10 minutes to obtain a blend coating solution of acrylic resin and silicone resin containing alumina particles. A sintered ferrite powder [(MgO) _1.8 (MnO) _49.5 (Fe ₂ O ₃ ) _48.0 : average particle diameter: 35 μm] was used as the core material, and the coating film forming solution was applied to the surface of the core material. The coating was applied with a Spiracoater (manufactured by Okada Seiko Co., Ltd.) to a thickness of 0.15 μm and dried. The obtained carrier was left in an electric furnace at 150° C. for 1 hour to be sintered. After cooling, the ferrite powder bulk was pulverized using a sieve with an opening of 106 μm to obtain a carrier. Since the coating film covering the surface of the carrier can be observed by observing the cross section of the carrier with a transmission electron microscope, the binder resin film thickness was measured as the average value of the film thickness.
Thus, a carrier having a weight average particle size of 35 μm was obtained.

<Preparation of two-component developer>
Using the above [toner 1] to [toner 10] and the above ferrite carrier, 100 parts of the carrier and 7 parts of the toner are uniformly mixed using a Turbula mixer of a type in which the container rolls and is stirred, and charged to develop. agent was produced.

<Fabrication of Cleaning Blades of Examples and Comparative Examples>
The lower surface of the substrate was masked leaving a width of 4 mm from the tip surface of a strip-shaped substrate having a thickness of 1.8 mm, and the curable compositions of Examples and Comparative Examples were applied to the lower surface of the substrate to form a surface layer with various average thicknesses. It was coated so that it would be
Specifically, the entire lower surface of the base material was overcoated by spray coating at a spray gun moving speed of 6 mm/s from the tip surface of the base material. Thereafter, the masking was removed, and after heating in a 90° C. constant temperature bath for 1 hour, the reaction was completed by standing in a 45° C./90% RH constant temperature bath for 48 hours. After that, a contact portion was formed by cutting at a distance of 1 mm from the tip surface.
Next, each elastic member having a surface layer formed on the contact portion was fixed to a sheet metal holder (supporting member) with an adhesive so as to be mounted on a process cartridge of a color multifunction machine (imagio MP C4500, manufactured by Ricoh Co., Ltd.). . As described above, the cleaning blades of the example and the comparative example having the surface layer formed on the contact portion were produced.
Various properties of the produced cleaning blade were measured as follows.

<Martens Hardness HM of Surface Layer>
The Martens hardness (HM) of the surface layer in Examples and Comparative Examples was measured as described above. The measurement position was set at a position 20 μm in the depth direction from the tip ridgeline. In addition, the measurement location was a position excluding the 2 cm portion at both ends.

<Average film thickness of surface layer>
FIG. 8 is a cross-sectional view showing measurement locations of the thickness of the contact portion of the cleaning blade in Examples and Comparative Examples.
As shown in FIG. 8, the elastic member was sliced in a plane orthogonal to the longitudinal direction, and the cross section was observed with a digital microscope VHX-2000 (manufactured by KEYENCE CORPORATION) facing upward. The measurement point is the blade contact portion (tip ridgeline portion) of the cross section. As a method for cutting the elastic member into round slices, the elastic member was cut with a razor perpendicularly to the longitudinal direction so that the thickness in the longitudinal direction of the elastic member was 3 mm. At that time, if a vertical slicer is used, the cross section can be cut more neatly. The position in the longitudinal direction where the elastic member was sliced was the position excluding the 2 cm portion at both ends.

Table 4 shows the results of the measurement as described above.

<Assembly of Image Forming Apparatus>
The cleaning blades produced in Examples and Comparative Examples were attached to a process cartridge of a color multifunction machine (imagio MP C4500, manufactured by Ricoh Co., Ltd.) (the printer section has the same configuration as the image forming apparatus 500 shown in FIG. 5), and further, the cleaning blades were produced. A toner cartridge was filled with the developer, and the image forming apparatuses of Examples and Comparative Examples were assembled.
The cleaning blade was attached to the image forming apparatus so that the linear pressure was 20 g/cm and the cleaning angle was 79°. Further, the apparatus is provided with a device for applying a lubricant to the surface of the photoreceptor, and the static friction coefficient of the surface of the photoreceptor is maintained at 0.2 or less during non-image formation by applying the lubricant. A method for measuring the coefficient of static friction of the surface of the photoreceptor is described in, for example, paragraph No. 0057 of Japanese Patent Application Laid-Open No. 2007-178619 by the Euler belt method.

<Cleanability>
As an evaluation image, 20 sheets of a vertical band pattern (with respect to the direction of paper travel) with a width of 43 mm and 3 horizontal charts of A4 size were output, and the obtained images were visually observed. Cleanability was evaluated.
[Evaluation criteria]
⊚: The toner that has passed through due to poor cleaning cannot be visually confirmed on the printed paper or on the photoreceptor.
◯: Toner slipped through due to poor cleaning cannot be visually observed on the printed paper or on the photoreceptor.
Δ: Toner slipped through due to poor cleaning cannot be visually observed on the printed paper, but can be slightly observed on the photoreceptor.
x: Toner slipped through due to poor cleaning can be visually observed on both the printed paper and the photoreceptor.

<Cleanability over time>
After outputting 100,000 sheets of the above evaluation image, the photoreceptor was taken out, and the residual toner on the photoreceptor that had passed through the cleaning blade was collected with a printer tac C (thickness: 25 μm) manufactured by Nitto Denko Co., Ltd., and pasted on a blank sheet of paper. Using a spectrodensitometer (manufactured by X-Rite), the ID was measured at 10 points with an observation light source of D50 and a viewing angle of 2°, and the average value was calculated.
[Evaluation criteria]
◎: Difference from blank is less than 0.005 ○: Difference from blank is 0.005 to less than 0.010 △: Difference from blank is 0.010 to less than 0.015 ×: Difference from blank is 0.015 015 or more ⊚ and ◯ are considered to have good cleaning properties.

<Photoreceptor filming>
The image forming apparatus was left in a constant temperature bath at 45° C./95% RH for 10 days. After that, in a laboratory environment of 23° C./50% RH, the image forming apparatus was used to continuously print 5 halftone images and 10,000 sheets. ) was observed. Evaluation was performed according to the following criteria.
[Evaluation criteria]
◎: No filming is observed ○: Very slight filming is observed, but at a satisfactory level △: Very small filming is observed in some places, or scratches are observed on the surface ×: Large filming has occurred, or many scratches are found on the surface

Table 5 shows the results.

Aspects of the present invention are, for example, as follows.
<1> an image carrier;
a developing means provided with the toner for developing the electrostatic latent image formed on the image carrier with the toner to form a visible image;
cleaning means for removing residual toner remaining on the image carrier with a cleaning blade;
A process cartridge having
the cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner remaining on the image carrier;
The elastic member has a base material and a surface layer provided on the base material,
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the substrate including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction,
The Martens hardness HM has a measured value at a load of 1 μN and a measured value at a load of 1000 μN of 2.5 N/mm ² or more and 32.5 N/mm ² or less,
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less,
In the process cartridge, the toner contained in the developing means has a circularity of less than 0.950 and a fine powder content of 2 μm or less of 20% or more and 60% or less by number.
<2> The surface layer contains a siloxane compound,
The process cartridge according to <1>, wherein the content of the siloxane-based compound in the surface layer is 8% by mass or more and 15% by mass or less.
<3> The process cartridge according to any one of <1> to <2>, wherein the toner provided in the developing means has a circularity of less than 0.945.
<4> The process cartridge according to any one of <1> to <3>, wherein the toner provided in the developing means has a circularity of less than 0.940.
<5> The process cartridge according to any one of <1> to <4>, wherein in the toner provided in the developing means, the fine powder of 2 μm or less has a circularity of 0.950 or more and 0.985 or less.
<6> an image carrier;
a developing means provided with the toner for developing the electrostatic latent image formed on the image carrier with the toner to form a visible image;
cleaning means for removing residual toner remaining on the image carrier with a cleaning blade;
An image forming apparatus having
the cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner remaining on the image carrier;
The elastic member has a base material and a surface layer provided on the base material,
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the substrate including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction,
The Martens hardness HM has a measured value at a load of 1 μN and a measured value at a load of 1000 μN of 2.5 N/mm ² or more and 32.5 N/mm ² or less,
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less,
In the image forming apparatus, the toner provided in the developing means has a circularity of less than 0.950 and a fine powder content of 2 μm or less of 20% by number or more and 60% by number or less.
<7> An image forming method comprising using the process cartridge according to any one of <1> to <5>.

The process cartridge described in <1> to <5>, the image forming apparatus described in <6>, and the image forming method described in <7> solve the problems in the conventional art, and solve the problems of the present invention. can achieve the purpose of

REFERENCE SIGNS LIST 1 image forming unit 2 frame 3 photoreceptor 4 charging roller 5 developing device 6 cleaning device 7 primary transfer roller 10 lubricant applying device 14 intermediate transfer belt 40 optical writing unit 41 polygon mirror 51 developing roller 52 supply screw 53 stirring screw 54 Doctor 55 registration roller pair 60 transfer unit 62 cleaning blade 62a blade tip surface 62b blade lower surface 62c tip ridge line portion 621 support member 622 base material 623 surface layer 624 elastic member 63 first bracket 64 second bracket 66 secondary transfer backup roller 67 drive Roller 68 Auxiliary Roller 69 Tension Roller 70 Secondary Transfer Roller 80 Fixing Unit 81 Pressure Heating Roller 82 Fixing Belt Unit 83 Heating Roller 84 Fixing Belt 85 Tension Roller 86 Drive Roller 87 Discharge Roller Pair 88 Stack Section 100 Toner Cartridge 101 Fur Brush 103 Solid Lubricant 103a Lubricant Pressure Spring 103b Bracket 123 Image Carrier 151 First Paper Feed Cassette 151a First Paper Feed Roller 152 Second Paper Feed Cassette 152a Second Paper Feed Roller 153 Paper Feed Path 154 Conveying Roller Pair 162 Belt Cleaning unit 162a Belt cleaning blade 500 Image forming apparatus (printer)

JP 2018-072806 A

Claims (7)

an image carrier;
a developing means provided with the toner for developing the electrostatic latent image formed on the image carrier with the toner to form a visible image;
cleaning means for removing residual toner remaining on the image carrier with a cleaning blade;
A process cartridge having
the cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner remaining on the image carrier;
The elastic member has a base material and a surface layer provided on the base material,
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the substrate including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction,
The Martens hardness HM has a measured value at a load of 1 μN and a measured value at a load of 1000 μN of 2.5 N/mm ² or more and 32.5 N/mm ² or less,
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less,
A process cartridge, wherein the toner contained in the developing means has a circularity of less than 0.950 and a content of fine powder of 2 μm or less of 20% by number or more and 60% by number or less. The surface layer contains a siloxane compound,
2. A process cartridge according to claim 1, wherein the content of said siloxane compound in said surface layer is 8% by mass or more and 15% by mass or less. 3. A process cartridge according to claim 1, wherein said toner provided in said developing means has a circularity of less than 0.945. 4. A process cartridge according to claim 1, wherein said toner provided in said developing means has a circularity of less than 0.940. 5. A process cartridge according to any one of claims 1 to 4, wherein in said toner provided in said developing means, fine powder of 2 [mu]m or less has a circularity of 0.950 or more and 0.985 or less. an image carrier;
a developing means provided with the toner for developing the electrostatic latent image formed on the image carrier with the toner to form a visible image;
cleaning means for removing residual toner remaining on the image carrier with a cleaning blade;
An image forming apparatus having
the cleaning blade includes an elastic member that contacts the surface of the image carrier and removes the residual toner remaining on the image carrier;
The elastic member has a base material and a surface layer provided on the base material,
When the surface of the base material facing the downstream side of the image carrier in the traveling direction of the image carrier with respect to the contact part of the elastic member that contacts the image carrier is defined as the lower surface of the base material, the surface layer is the contact portion. is formed on at least a portion of the lower surface of the substrate including
The surface layer has a hardness gradient in which the Martens hardness HM measured using a nanoindenter decreases from the surface toward the bottom surface of the substrate in the film thickness direction,
The Martens hardness HM has a measured value at a load of 1 μN and a measured value at a load of 1000 μN of 2.5 N/mm ² or more and 32.5 N/mm ² or less,
The average film thickness of the surface layer at the contact portion is 10 μm or more and 500 μm or less,
An image forming apparatus, wherein the toner provided in the developing means has a circularity of less than 0.950 and a fine powder content of 2 μm or less of 20% by number or more and 60% by number or less. An image forming method, comprising using the process cartridge according to any one of claims 1 to 5.

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