JP6390449B2 - Solid lubricant, solid lubricant application device, and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus provided with a solid lubricant application device, wherein the solid lubricant composition contains a metal soap mainly composed of a higher fatty acid metal salt and a tetrafluoroethylene oligomer having a terminal group converted to -CF3. It relates to a lubricant.

  JP 2011-170155 A (Patent Document 1), JP 2007-108327 A (Patent Document 2), JP 2004-126382 A (Patent Document 3), and JP 2002-268400 A (Patent Document 2). Documents 4) each disclose an image forming apparatus.

JP 2011-170155 A JP 2007-108327 A JP 2004-126382 A JP 2002-268400 A

  In recent years, in image forming apparatuses, it is necessary to sufficiently prevent the occurrence of image noise such as image blurring and image flow as image formation speeds up. It is important to suppress wear of the cleaning blade that cleans.

  In the image forming apparatus disclosed in Patent Document 1, as a lubricant used in the cleaning apparatus, in order to optimize the contact between the cleaning blade and an image carrier (photoconductor) on which an electrostatic latent image is formed. A technique for applying a solid lubricant containing a fatty acid metal salt and a fluororesin to an image carrier using a brush is disclosed.

  Patent Document 2 discloses a technique in which a lubricant of a polytetrafluoroethylene (PTFE) molded body crosslinked by radiation is directly applied to an image carrier in order to optimize the contact between the cleaning blade and the image carrier. It is disclosed.

  In Patent Document 3, a lubricant containing polytetrafluoroethylene (low molecular weight PTFE) having a low low molecular weight (average molecular weight of several hundred thousand or less) is used. This low molecular weight PTFE is produced by controlling the molecular weight by a polymerization method, a radiolysis method, a thermal decomposition method or the like, and its average molecular weight is kept low. By keeping the average molecular weight low, the effect of the lubricant is exerted.

  Patent Document 4 discloses that the surface friction coefficient of an image carrier is maintained within an appropriate range by using a lubricant containing a fluororesin.

  However, in recent years, image forming apparatuses are required to increase the speed of image formation, and further suppression of surface wear of the image carrier and suppression of wear of a cleaning blade for cleaning the image carrier are being demanded.

  An object of the present invention has been made in view of the above problems, and is a solid lubricant capable of achieving both suppression of surface wear of an image carrier and suppression of wear of a cleaning blade for cleaning the image carrier, It is an object of the present invention to provide a solid lubricant coating device including a solid lubricant and an image forming apparatus including the solid lubricant coating device.

This solid lubricant is used in an image forming apparatus that performs each process of charging, exposure, development, and transfer, and is a solid lubricant that is applied to the surface of an image carrier that temporarily carries a toner image, A metal soap containing at least a fatty acid metal salt as a main component and a tetrafluoroethylene oligomer represented by the following general formula (1) are contained. However, m represents a positive number of 5 to 500.
General formula (1): CF3- (CF2-CF2) m-CF3
In another embodiment, the metal soap as a main component is zinc stearate.

In another embodiment, the metal soap as a main component is magnesium stearate.
In this solid lubricant coating device, a lubricant coating member that coats while deforming the outer shape in response to biting on the surface of the image carrier, and a lubricant supply unit that feeds the solid lubricant to the lubricant coating member And the solid lubricant is any of the solid lubricants described above.

  This image forming apparatus is an image forming apparatus that performs each process of charging, exposure, development, and transfer, and an image carrier on which an electrostatic latent image is formed by a charging unit, and an electrostatic latent image of the image carrier. A developing device that forms a toner image by an image; and a solid lubricant coating device that applies a solid lubricant to the surface of the image carrier. The solid lubricant coating device is the solid lubricant coating device described above. .

  In this invention, it is possible to achieve both suppression of surface wear of the image carrier and suppression of wear of a cleaning blade for cleaning the image carrier, a solid lubricant, and a solid lubricant application device including the solid lubricant, An image forming apparatus including the solid lubricant application device is also provided.

FIG. 2 is a schematic diagram of a solid lubricant, a solid lubricant coating device including the solid lubricant, and an image forming apparatus including the solid lubricant coating device in the present embodiment. It is a figure which shows the conditions of TFF oligomer (1)-(6) in this Embodiment. It is a figure which shows the result of the various evaluation of Example 1 to Example 8 and Comparative Example 1 to Comparative Example 3 of the solid lubricant in this Embodiment. FIG. 6 is a schematic diagram of a solid lubricant, a solid lubricant application device including the solid lubricant, and an image forming apparatus including the solid lubricant application device according to another embodiment.

  A solid lubricant, a solid lubricant application device including the solid lubricant, and an image forming apparatus including the solid lubricant application device according to an embodiment of the present invention will be described below with reference to the drawings. In the embodiments described below, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated. It is planned from the beginning to use a combination of the configurations in each embodiment as appropriate.

  As a result of intensive studies on the solid lubricant used in the image forming apparatus, the inventors have focused on the friction characteristics of polytetrafluoroethylene (hereinafter referred to as PTFE) and further improved its general characteristics to improve the lubricity. In order to increase the molecular weight, it has been found that lowering the molecular weight of PTFE (average molecular weight is several hundreds of thousands or less) is effective. However, as a result of the experiment, it was found that the influence of the functional group (hydrophilic group) at the end of PTFE becomes obvious.

  Specifically, a cleaning failure or an image blur (hereinafter referred to as an HH image blur) generated in a high-temperature and high-humidity environment due to a large variation in the friction coefficient due to the environmental variation occurs. In order to improve this, tuning of the coating amount was tried, but it was not possible to achieve a good balance. As a result of further diligent investigation, the end of PTFE was treated with CF3 to reduce the fluctuation of the friction coefficient due to the environment, resulting in poor cleaning and It has been found that the resistance to HH image blur is improved, the effect of reducing the friction coefficient is further increased, the amount of lubricant applied can be further reduced, and it contributes to a longer life and compactness of the solid lubricant application device.

  Here, none of the above-mentioned Patent Documents 1 to 4 describes PTFE end treatment. In order to enhance the action of the lubricant, it is desirable that it is a soft substance, has a small cohesive force between molecules, and easily slips between molecules. That is, it can be said that low molecular weight PTFE is effective.

  In addition, the lower the molecular weight PTFE, the greater the influence on the physical properties of the end groups relative to the high molecular weight PTFE. General low molecular weight PTFE is produced by various methods. Among them, a method of telomerizing tetrafluoroethylene (hereinafter referred to as TFE) (refer to Japanese Patent Publication No. 51-25275), and thermally decomposing PTFE. Examples thereof include a method (see Japanese Patent Publication No. 50-15506), a decomposition method of PTFE by irradiation (see Japanese Patent Publication No. 52-25419), a method of generating from a gas phase dispersion state, and the like.

  However, the method by telomerization, the method by thermal decomposition, and the decomposition method by radiation irradiation have a highly hydrophilic structure containing hydrogen at the production end, so that the environmental dependency is increased and the lubricity is also affected. Regarding the hydrophobicity of the TFE oligomer, it is considered that the fact that the terminal is a perfluoro group has a decisive difference from other functional groups.

Here, in order to perfluorinate the terminal as represented by the following general formula (1), a method of generating from a gas phase dispersion state is preferable. As a specific example, PTFE is heated and gasified to a melting point or higher. In this method, the gas and the fluorinating agent are contact-reacted.
General formula (1): CF3- (CF2-CF2) m-CF3
Examples of the fluorinating agent to be supplied include compounds such as molecular fluorine, nitrogen trifluoride, chlorine trifluoride, bromine trifluoride, iodine trifluoride, and krypton fluoride. These fluorides are fluorinating agents that generate fluorine radicals. Fluorine radicals facilitate the reaction by cleaving the main chain of the fluororesin and stabilizing the coupling of the resulting low molecular weight terminal radicals. is there. For this reason, the reaction product has a low molecular weight and decomposes in the presence of active fluorine radicals, so that the terminal is fluorinated and is extremely stable.

  Since the molecular weight of PTFE, which is usually widely used for various applications, is one having an extremely high degree of polymerization of 1,000,000 or more, it is considered that the terminal group hardly affects the physical properties. However, in a TFE oligomer having a molecular weight of several hundreds of thousands or less, the terminal functional group is a relatively important factor, and it has an influence on the reaction energy, surface energy, water repellency, friction coefficient, and the like. .

(Solid lubricant, solid lubricant application device, and image forming device)
First, the configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram of a solid lubricant, a solid lubricant coating device including the solid lubricant, and an image forming apparatus including the solid lubricant coating device according to the present embodiment.

  An image forming apparatus 100 shown in FIG. 1 includes a photoconductor (image carrier) 101, a charging unit 102, a developing unit 104, a transfer unit 105, a cleaning blade 108 as a cleaning unit, a lubricant applying member 106, a solid lubricant 107, A pressing unit 109 as a lubricant supply unit and a leveling unit 120 are provided. The lubricant application member 106, the solid lubricant 107, the pressing means 109, and the leveling means 120 constitute a solid lubricant application device 110.

  The cleaning blade 108 is obtained by processing polyurethane rubber into a sheet having a thickness of about 2 mm by a centrifugal molding machine. The cleaning blade 108 extends in the depth direction, and is adhered to the holding sheet metal with a hot melt adhesive. The cleaning blade 108 is pressed against the photoconductor 101 and scrapes off transfer residual toner adhering to the rotating photoconductor 101.

  The solid lubricant application device 110 extends in the depth direction in the drawing. The lubricant application member 106 rotates in the opposite direction (that is, counter direction) to the photoconductor 101. Such a solid lubricant application device 110 is arranged such that the lubricant application member 106 is in contact with the surface of the photoreceptor 101.

  The lubricant application member 106 extends in the depth direction in the drawing. The lubricant application member 106 includes a metal shaft 106a and an application brush 106b. The application brush 106b is woven into a base cloth held by the shaft 106a and formed in a roll shape. In addition, the application brush 106b rotates in the same direction as the photoreceptor 101 (that is, the counter direction) about the shaft 106a. Such a lubricant application member 106 is disposed so that the application brush 106 b is in contact with the surface of the photoreceptor 101.

Here, an example of detailed specifications of the lubricant application member 106 will be described. The material of the application brush 106b is conductive acrylic, and the resistance value as a fiber is about 10 ⁶ Ω. The coating brush 106b has a fiber thickness of 3T (decitex) and a fiber density of 225 kF / inch ² . The shaft 106a is made of iron and has a diameter of 6 mm. The outer diameter of the application brush 106b is φ12 mm, but the length of the fiber is about 3.0 mm because the fiber is woven on a base cloth having a thickness of about 0.5 mm.

  The solid lubricant 107 is provided below the lubricant application member 106. The solid lubricant 107 is urged upward by a pressing means 109 using a spring, for example, and is pressed against the application brush 106 b of the lubricant application member 106.

  As with the cleaning blade 108, the leveling means 120 is obtained by fixing a plate-like polyurethane rubber manufactured by a centrifugal molding machine to a holding metal plate through hot melt bonding, and in the trail direction with respect to the photoreceptor 101. It is in contact.

  The lubricant application member 106 rotates in the same direction (counter direction) as the rotation direction B about the shaft 106a. The lubricant is scraped off from the solid lubricant 107 by the rotation of the lubricant application member 106 and the urging force of the pressing means 109, and returned to a powder form. Hereinafter, this powder is referred to as a lubricant particle. The lubricant particles adhere to the application brush 106 b and are supplied to the surface of the photoreceptor 101 by the rotation of the lubricant application member 106.

The lubricant particles adhering to the surface of the photoconductor 101 are conveyed to the leveling means 120 by the rotation of the photoconductor 101. The leveling means 120 forms a lubricant film by forming the lubricant particles into a film by a pressing force on the surface of the photoreceptor 101. Here, as will be described later, the solid lubricant 107 includes at least magnesium stearate, zinc stearate, other metal soaps, and tetrafluoro represented by the following general formula (1). An ethylene (TFE) oligomer (TFE) may be contained. However, in the following general formula (1), m represents a positive number of 5 to 500.
General formula (1): CF3- (CF2-CF2) m-CF3
In this case, the formed lubricant film is characterized by high releasability and a low friction coefficient. As a result, the cleaning property is good regardless of the environment, and wear of the photosensitive member 101 can be suppressed. As a result, the lifetime of the photoconductor 101 and the cleaning blade 51 can be extended.

  The lubricant applying member 106 is preferably a member that applies the solid lubricant 107 while deforming its outer shape according to the biting into the surface of the image carrier 101, and examples thereof include a brush and a sponge.

  The image forming apparatus 100 performs charging, exposure, development, and transfer processes. On the photoreceptor (image carrier) 101, an electrostatic latent image is formed by the charging unit 102, and a toner image is temporarily formed by the developing device 104. Thereafter, the toner image on the photoconductor (image carrier) 101 is transferred to a transfer member (paper or the like) P by the transfer unit 105.

[TFE oligomer production example]
Next, production examples of various tetrafluoroethylene oligomers (hereinafter referred to as “TFE oligomers”) used for the solid lubricant 107 will be described. FIG. 2 is a diagram showing conditions of TFF oligomers (1) to (6).

<Production Example (1): Production of TFE oligomer (1)>
400 g of PTFE pellets were charged into a 15 L nickel reactor equipped with a fan and a heater for forced gas stirring. Thereafter, the temperature inside the 15 L nickel reactor was raised to 450 ° C. with a heater in a nitrogen atmosphere. Then, while supplying fluorine gas (5 vol%) diluted with nitrogen gas directly to the sample, the reaction product gas is drawn out from the outlet of the reactor, and fluorine gas (1 vol%) diluted with room temperature nitrogen gas in a collection container And the mixture was cooled and precipitated, and the remaining gas was externally returned to the reactor.

  After 8 hours of reaction, 360 g of white powder was obtained. The melting point of this powder was 317 ° C. and the molecular weight was 10,300. This was designated as TFE oligomer (1).

<Production Example (2): Production of TFE oligomer (2)>
As in Example 1, 400 g of PTFE pellets were charged into a nickel reactor. Then, after raising the temperature to 420 ° C. with a heater in a nitrogen atmosphere, the reaction product gas is drawn out from the reactor outlet while supplying fluorine gas (5 vol%) diluted with nitrogen gas directly to the sample, and the collection container The mixture was internally mixed with fluorine gas (1 vol%) diluted with nitrogen gas at room temperature, cooled and precipitated, and the remaining gas was externally returned to the reactor.

  After 5 hours of reaction, 350 g of white powder was obtained. The melting point of this powder was 306 ° C., and the molecular weight was 4,800. This was designated as TFE oligomer (2).

<Production Example (3): Production of TFE oligomer (3)>
The temperature of the nickel reactor was raised to 500 ° C. with a heater, and fluorine gas (5 vol%) diluted with nitrogen gas was introduced at 1 l / min, and TFE oligomer (6) described later was continuously added at 15 g / hr. Supplied to. The reaction product gas was drawn from the reactor outlet at 30 to 40 l / min using a suction pump, cooled and precipitated in the collection vessel, and the remaining gas was externally circulated back into the reactor.

  After reacting for 5 hours, 40 g of white powder was obtained. The melting point of this powder was 229 ° C. and the molecular weight was 900. This was designated as TFE oligomer (3).

<Production Example (4): Production of TFE Oligomer (4)>
The temperature of the nickel reactor was raised to 520 ° C. with a heater, fluorine gas diluted with nitrogen gas (5 vol%) was introduced at 1.5 l / min, and PTFE pellets were continuously supplied at 15 g / hr. . The reaction product gas was drawn from the outlet of the reactor at a rate of 20 to 30 l / min using a suction pump, cooled and precipitated in a collection vessel, and the remaining gas was externally circulated back into the reactor.

  After reacting for 10 hours, 50 g of white powder was obtained. The melting point of this powder was 324 ° C. and the molecular weight was 35,000. This was designated as TFE oligomer (4).

<Production Example (5): TFE oligomer (5), method by telomerization>
A 6 L stainless steel autoclave was charged with 3500 g of deionized water, 100 g of paraffin wax and 5.25 g of ammonium perfluorooctanoate, and the system was replaced with nitrogen gas while heating to 85 ° C. Thereafter, the internal pressure was adjusted to 0.70 MPa with TFE gas, and the inside of the system was kept at 85 ° C. while stirring.

  After the temperature in the polymerization tank was stabilized, an aqueous solution in which 15 mg of ammonium persulfate was dissolved in 50 g of deionized water and an aqueous solution in which 250 mg of disuccinic acid peroxide was dissolved in 50 g of deionized water were injected with TFE, and the internal pressure of the autoclave was adjusted to 0.80 MPa. The TFE was continuously supplied while maintaining the temperature. When the amount of TFE consumption reached 1000 g, stirring and TFE supply were stopped, and the gas in the autoclave was released to normal pressure to complete the reaction.

  The obtained TFE oligomer liquid was separated by filtration to obtain 1000 g of a white powder. The melting point of this powder was 323 ° C., and the molecular weight was 26,000. This was designated as TFE oligomer (5).

<Production Example (6): TFE oligomer (6), decomposition method by irradiation>
50 g of PTFE pellets were irradiated with cobalt 60 gamma rays in the atmosphere for 10 hours at a dose rate of 500 Gy / hr.

  The pulverized powder had a melting point of 320 ° C. and a molecular weight of 15,000. This was designated as TFE oligomer (6).

(Example)
Hereinafter, Examples 1 to 8 and Comparative Examples 1 to 3 of solid lubricants using the TFE oligomers (1) to (6) will be described. In FIG. 3, the result of various evaluation of Example 1 to Example 8 and Comparative Example 1 to Comparative Example 3 is shown.

[Example 1: Production of solid lubricant (1)]
170 parts of magnesium stearate and 30 parts of TFE oligomer (1) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 15%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (1) was taken out.

[Example 2: Production of solid lubricant (2)]
170 parts of zinc stearate and 30 parts of TFE oligomer (1) were mixed in a Henschel mixer (the solid lubricant had a TFE oligomer content of 15%), and the resulting powder was placed in a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (2) was taken out.

[Example 3: Production of solid lubricant (3)]
170 parts of zinc stearate and 30 parts of TFE oligomer (2) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 15%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (3) was taken out.

[Example 4: Production of solid lubricant (4)]
180 parts of zinc stearate and 20 parts of TFE oligomer (2) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 10%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (3) was taken out.

[Example 5: Production of solid lubricant (5)]
190 parts of zinc stearate and 10 parts of TFE oligomer (2) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 5%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (5) was taken out.

[Example 6: Production of solid lubricant (6)]
180 parts of zinc stearate and 20 parts of TFE oligomer (3) were mixed in a Henschel mixer (the solid lubricant had a TFE oligomer content of 10%), and the resulting powder was placed in a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (5) was taken out.

[Example 7: Production of solid lubricant (7)]
190 parts of zinc stearate and 10 parts of TFE oligomer (3) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 5%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (7) was taken out.

[Example 8: Production of solid lubricant (8)]
160 parts of zinc stearate and 40 parts of TFE oligomer (4) were mixed in a Henschel mixer (the TFE oligomer content of the solid lubricant was 20%), and the obtained powder was put into a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (8) was taken out.

[Comparative Example 1: Production of solid lubricant (9)]
170 parts of zinc stearate and 30 parts of TFE oligomer (5) were mixed in a Henschel mixer (the solid lubricant had a TFE oligomer content of 15%), and the resulting powder was placed in a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (9) was taken out.

[Comparative Example 2: Production of solid lubricant (10)]
170 parts of zinc stearate and 30 parts of TFE oligomer (6) were mixed in a Henschel mixer (the solid lubricant had a TFE oligomer content of 15%), and the resulting powder was placed in a glass container with a lid, and 140 ° C. Then, the mixture was melted with stirring by a hot stirrer whose temperature was controlled. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (10) was taken out.

[Comparative Example 3: Production of solid lubricant (11)]
200 parts of zinc stearate (the TFE oligomer content of the solid lubricant was 0%) was placed in a glass container with a lid and melted with stirring by a hot stirrer whose temperature was controlled at 140 ° C. The molten lubricant composition was poured into a mold heated to 100 ° C., allowed to cool in a room temperature atmosphere, and then the solid lubricant (11) was taken out.

  Using the solid lubricants (1) to (11) in Examples 1 to 8 and Comparative Examples 1 to 3 obtained as described above, Bizhub Pro 1100 (tandem type color image forming apparatus, manufactured by Konica Minolta) Each of the four color process cartridges (image forming apparatus) was mounted for various evaluations. The evaluation results are shown in FIG.

  As an example of the lubricant application member 106 (see FIG. 1) of the process cartridge, a solid lubricant application brush was used. As the solid lubricant application brush, an electrostatic flocking brush made of polyester having a hair thickness of (3d) was used. As the pressing means 109 (see FIG. 1), the solid lubricant 107 was pressed against the solid lubricant application brush 106 with a spring pressure of 3.5 N.

"Evaluation 1": <Image blur in high temperature and high humidity environment>
An image 12 hours after the end of a 50,000-print live image when the linear lubricant application brush 106 is set to twice the standard linear velocity (application amount UP) in a high-temperature, high-humidity (30 ° C, 80% RH) environment. Was visually evaluated. Evaluation B is a level at which no image flow is recognized, Evaluation C is a level at which some image flow occurs and cannot be used, and Evaluation F is a level at which image flow occurs on the entire surface and cannot be used at all. is there. A rating B or higher is a practical level.

"Evaluation 2-1": <Image streaks in a low temperature and low humidity environment>
A cleaning blade 108 in which the edge portion was forcibly worn by 10 μm was attached in a low-temperature and low-humidity (10 ° C., 20% RH) environment, and the image after 50,000 print images were visually evaluated.

"Evaluation 2-2"
Under the conditions of Evaluation 2-1, the image after 50,000 print images were visually evaluated with the setting (application amount DOWN) in which the linear velocity of the solid lubricant application brush 106 was reduced by 30% from the standard linear velocity. Evaluation A is a level at which no streaks are observed, evaluation B is a level at which some streaks occur slightly, but there is no practical problem, and evaluation C is a level at which some streaks occur and cannot be used. F is a level at which uneven stripes occur on the entire surface and cannot be used at all. A rating B or higher is a practical level.

"Evaluation 3": <Cleaning blade wear amount and photoreceptor wear amount in a low temperature and low humidity environment>
After actual printing of 100,000 prints in a low temperature and low humidity (10 ° C., 20% RH) environment, the cleaning blade wear amount and the photoreceptor wear amount were evaluated. Evaluation B is a cleaning blade wear amount of 5 μm or less and a photoreceptor wear amount of 0.5 μm or less. Evaluation C is a cleaning blade wear amount of 8 μm or less and a photoreceptor wear amount of 0.8 μm or less. Evaluation F is a cleaning blade wear amount of 8 μm or more, or a photoreceptor wear amount of 0.8 μm or more. A rating B or higher is a practical level.

"Evaluation 4"
In a low-temperature and low-humidity (10 ° C, 20% RH) environment, install a cleaning blade with 10μm of the edge of the cleaning blade forcibly worn, change the spring load, and set the cleaning limit load for the same color (solid image) as follows Evaluated. Rank 5 is a cleaning limit load (N / m) of less than 15 (N / m), Rank 4 is a cleaning limit load (N / m) of 15 or more and less than 18 (N / m), and Rank 3 is a cleaning limit load (N / m). / M) is 18 or more and less than 21 (N / m), Rank 2 has a cleaning limit load (N / m) of 21 or more and less than 24 (N / m), and Rank 1 has a cleaning limit load (N / m) of 24 ( N / m) or more. If it is Rank3 or more, it is practical.

Although it is difficult to directly measure the molecular weight of the PTFE oligomer, for example, from the relationship between the melting point and the molecular weight, it can be determined according to the following formula described in US Pat. No. 3,067,262. The melting point Tm (K) was determined from the intersection of the base line and the maximum slope of the peak with a differential thermal analyzer: DTG-60A, Shimadzu Corporation at a heating rate of 10 ° C./min.
[Molecular weight] = 200/685 (1 / Tm-1 / 600)
From the above evaluation results, it was confirmed that in Examples 1 to 8, all evaluations were at a practical level. That is, the solid lubricant includes magnesium stearate, zinc stearate, and other metal soaps mainly composed of at least a fatty acid metal salt, and a tetrafluoroethylene (TFE) oligomer (TFE) represented by the following general formula (1). ). However, in the following general formula (1), m represents a positive number of 5 to 500.
General formula (1): CF3- (CF2-CF2) m-CF3
The image forming apparatus 100 shown in FIG. 1 shows a configuration in which the cleaning blade 108 is provided on the upstream side of the lubricant application member 106 when viewed from the rotation direction (arrow B direction) of the photoconductor 101. It is not limited to this configuration.

  The image forming apparatus 100A shown in FIG. 4 shows a configuration in which the cleaning blade 108 is provided on the downstream side of the lubricant application member 106 when viewed from the rotation direction of the photoconductor 101 (the direction of arrow B). Even if it exists, it is possible to obtain the same effect. Note that in the image forming apparatus 100A, the same or corresponding parts as those in the image forming apparatus 100 are denoted by the same reference numerals, and redundant description is omitted.

  It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 100 Image forming apparatus, 101 Photoconductor (image carrier), 102 Charging means, 104 Developing apparatus, 105 Transfer means, 106 Lubricant application member, 107 Solid lubricant, 108 Cleaning blade (cleaning means), 109 Press means (lubricant) Supply means), 110 solid lubricant application device.

Claims (5)

A solid lubricant used in an image forming apparatus that performs each process of charging, exposure, development, and transfer, and applied to the surface of an image carrier that temporarily carries a toner image,
A metal soap containing at least a fatty acid metal salt as a main component;
A tetrafluoroethylene oligomer represented by the following general formula (1);
Containing a solid lubricant.
General formula (1): CF3- (CF2-CF2) m-CF3
However, m represents a positive number of 5 to 500.   The solid lubricant according to claim 1, wherein the metal soap as a main component is zinc stearate.   The solid lubricant according to claim 1, wherein the metal soap as a main component is magnesium stearate. Lubricant application member that is applied while deforming the outer shape according to the biting into the image carrier surface,
Lubricant supply means for supplying the solid lubricant to the lubricant application member;
With
The solid lubricant is the solid lubricant according to any one of claims 1 to 3.
Solid lubricant application device. An image forming apparatus that performs each process of charging, exposure, development, and transfer,
An image carrier on which an electrostatic latent image is formed by charging means;
A developing device for forming a toner image by an electrostatic latent image of the image carrier;
A solid lubricant application device for applying a solid lubricant to the surface of the image carrier;
With
The solid lubricant application device is the solid lubricant application device according to claim 4,
Image forming apparatus.

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