JP5656662B2 - Developing roller and electrophotographic apparatus - Google Patents

Description

  The present invention relates to a developing roller used in an electrophotographic developing device.

  A developing roller used in an electrophotographic apparatus that develops an electrostatic latent image formed on a photosensitive drum by a contact developing method using a developer such as a non-magnetic one-component toner forms a stable nip with the photosensitive drum and develops it. A structure having a conductive elastic layer for applying an electric field is common. As a material for such an elastic layer, rubber obtained by dispersing electronic conductive particles such as carbon black is often used. Incidentally, a charging member having an elastic layer made conductive by an electron conductive conductive agent has a problem that its electric resistance characteristics are unstable.

With respect to such a problem, Patent Document 1 discloses a conductive member for OA equipment that can be used for a developing roller formed by molding a composition comprising non-ether polyurethane, carbon black, and bis (trifluoromethanesulfonyl) imide lithium. Disclosure. According to Patent Document 1, it is described that the above-described conductive member exhibits extremely stable electric resistance in a volume resistance region of 10 ⁵ to 10 ¹² Ω · cm, and the voltage dependency of conductivity is small. Further, as a reason for this, the conductive member is formed by a molding method because bis (trifluoromethanesulfonyl) imide lithium, which is an ionic conductive material, complements even when a defect occurs in the conductive path of carbon black. In addition, it is described that desired conductivity can be uniformly imparted to a molded product without strict adjustment of manufacturing conditions.

JP 2007-178752 A

The inventor has examined the use of the conductive member according to the invention of Patent Document 1 for the developing roller. As a result, the electrical resistance may gradually increase with long-term use.
And the fluctuation | variation of the electrical resistance may affect the quality of the electrophotographic image.
Accordingly, the present invention is directed to providing a developing roller in which the electrical resistance is less likely to change even after long-term use.

According to the present invention, the mandrel has an elastic layer provided et the the outer periphery of the mandrel, the elastic layer is a silicone rubber obtained by crosslinking the alkoxy-modified polysiloxanes, alkoxy-modified A developing roller containing silicone oil and carbon black is provided. Also provided is an electrophotographic apparatus having an electrophotographic photosensitive member and the above-described developing roller in contact with the electrophotographic photosensitive member.

  According to the present invention, it is possible to obtain a developing member in which the electrical resistance hardly increases even when a potential is continuously applied over a long period of time. As a result, an electrophotographic apparatus that can stably obtain a high-quality electrophotographic image can be obtained.

Schematic of electrophotographic apparatus according to the present invention Schematic diagram of a developing device showing an embodiment of the present invention Side surface and cross-sectional view of a developing roller showing an embodiment of the present invention Schematic of a resistance measuring device representing an embodiment of the present invention

The present inventors have studied the reason for the increase in electrical resistance over time of a developing roller provided with an elastic layer imparted with conductivity by electronic conductive particles. As a result, the following phenomenon is considered to be the cause.
That is, since the developing roller is brought into contact with the photosensitive drum or the like in the electrophotographic apparatus with a certain pressure, the elastic layer of the developing roller repeats deformation and recovery. A potential is applied to the developing roller. Under such circumstances, the electron conductive particles gradually move in the network structure of the crosslinked rubber, and the electron conductive particles are aggregated. As a result, it is considered that the electrical resistance of the developing roller increases due to long-term use.

In view of this, the present inventors have investigated the suppression of fluctuations in the dispersion state of the electroconductive particles in the elastic layer in order to suppress an increase in the electric resistance value of the developing roller due to long-term use in the electrophotographic apparatus. . Specifically, it was studied to suppress the movement of the electron conductive particles in the elastic layer.
As a result, by including the following (1) to (3) in the elastic layer of the developing roller, even if the developing roller is used in the printer for a long time, the movement of the electronic conductive particles is suppressed, and the electric resistance of the developing roller is reduced. It was found that the increase in value can be suppressed.
(1) A silicone rubber obtained by crosslinking an alkoxy-modified polysiloxane.
(2) Alkoxy-modified silicone oil.
(3) Carbon black.
The developing roller having an elastic layer containing the above (1) to (3) does not easily increase in electrical resistance even after long-term use. The alkoxy-modified polysiloxane in the present invention represents a polysiloxane having an alkoxy group in the molecule and a crosslinkable reactive functional group other than the alkoxy group. Alkoxy-modified silicone oil is a compound that has an alkoxy group in the molecule and does not bind to the crosslinked silicone rubber but exists in a liquid state in the silicone rubber, and is extracted by extraction using toluene or the like. Represents the component to be processed.

  In the present invention, it is necessary to contain a silicone rubber obtained by crosslinking an alkoxy-modified polysiloxane and an alkoxy-modified silicone oil. The oxygen atom of the alkoxy group of the crosslinked alkoxy-modified polysiloxane interacts with the hydroxyl group or carboxyl group on the surface of the carbon black and is taken into the crosslinked network, and the carbon black is fixed in the silicone rubber. Furthermore, since the alkoxy-modified silicone oil, which is a feature of the present invention, does not participate in the crosslinked structure, it has a higher degree of freedom and can move more easily than the alkoxy-modified polysiloxane. Therefore, not only the hydroxyl group or carboxyl group on the surface of the carbon black interacting with the crosslinked alkoxy-modified polysiloxane interacts with the hydroxyl group or carboxyl group on the surface of the carbon black that does not interact. Therefore, the effect of suppressing the movement of carbon black is very high. Further, the alkoxy-modified silicone oil having a certain molecular weight interacts with a plurality of carbon blacks, so that the distance between the carbon blacks is kept constant, and the agglomeration is less likely to occur. Therefore, in the present invention, by using an elastic layer containing a silicone rubber obtained by crosslinking alkoxy-modified polysiloxane and an alkoxy-modified silicone oil as a developing roller, the above-mentioned action works synergistically, Suppresses the movement of carbon black. Therefore, an increase in the resistance value of the developing roller can be reduced, and even if the developing roller is used for a long time in the printer, the negative ghost performance is good as when the printer is started.

In the crosslinked alkoxy-modified polysiloxane, the number of carbon atoms in R ¹ of the alkoxy group represented by —OR ¹ in Formula 1 is preferably 1 or more and 5 or less, and more preferably 1 or 2. By setting the carbon number of R ¹ within the above range, R ¹ does not become too sterically large, and interaction between the oxygen atom of the alkoxy group and the hydroxyl group or carboxyl group on the carbon black surface due to steric hindrance. It is possible to suppress inhibition. As a result, the carbon black can be more reliably fixed, and the increase in resistance of the developing roller over time can be better suppressed. For the same reason, also in the alkoxy-modified silicone oil, it is preferable that the alkoxy group has 1 to 5 carbon atoms, particularly 1 to 2 carbon atoms.

  The weight average molecular weight of the alkoxy-modified silicone oil is preferably 3000 or more and 20000 or less, and more preferably 4000 or more and 15000 or less. When the weight average molecular weight of the alkoxy-modified silicone oil is within the above range, the carbon black can be more reliably fixed. Further, even during long-term pressure contact with the photosensitive drum and the toner regulating member, bleeding to the surface is difficult to occur.

A silicone rubber obtained by crosslinking an alkoxy-modified polysiloxane has a structure represented by the following formula 1 (R ¹ , R ² , R ³ , R ⁴ may be the same hydrocarbon having 1 to 5 carbon atoms), And it is preferable that l and m are 1 / m ≦ 120. By setting l / m to 120 or less, the number of alkoxy groups interacting with the carbon black particles in the elastic layer is ensured, and the fixing effect of carbon black can be expressed more reliably. The values of l and m were determined from the peak area ratio obtained by cutting out the elastic layer and measuring ¹³ C NMR.

As a guideline for the content of the alkoxy-modified silicone oil, considering the suppression of bleeding of the alkoxy-modified silicone oil from the elastic layer, it is 0.5% by mass or more and 6.0% by mass or less with respect to the mass of the elastic layer. In particular, the content is preferably 1.0% by mass or more and 5.0% by mass or less.

The silicone rubber obtained by crosslinking the alkoxy-modified polysiloxane in the present invention can be obtained by an addition reaction between a polysiloxane having an alkoxy group and an alkenyl group in the molecule and a polysiloxane having an SiH group in the molecule. it can.
The polysiloxane having an alkoxy group and an alkenyl group in the molecule preferably has at least two alkoxy groups in the molecule and further has at least two alkenyl groups in the molecule. Moreover, as polysiloxane having an alkoxy group and an alkenyl group in the molecule, both terminal dialkylalkenylsiloxy-alkylalkoxysiloxane-dialkylsiloxane copolymer, both terminal dialkylalkoxysiloxy-alkenylalkylsiloxane-dialkylsiloxane copolymer, both terminal A trimethylsiloxy-alkoxyalkylsiloxane-alkenylalkylsiloxane-dialkylsiloxane copolymer, dialkylalkoxysiloxy-alkylalkoxysiloxane-alkenylalkylsiloxane-dialkylsiloxane copolymer at both ends, and the like can be used.

The molecular structure of the polysiloxane having an alkoxy group and an alkenyl group in the molecule can be used without any particular limitation, such as a linear or branched one.
The weight average molecular weight of the polysiloxane having an alkoxy group and an alkenyl group in the molecule is preferably in the range of 500 to 1,000,000. A mixture of polysiloxanes having a weight average molecular weight of one kind or a plurality of kinds of polysiloxanes having different weight average molecular weights may be used.
The polysiloxane having SiH groups preferably has two or more SiH groups in the molecule. As polysiloxane having SiH group, both terminal trialkylsiloxy-alkylhydrogensiloxane, both terminal trialkylsiloxy-alkylhydrogensiloxane-dialkylsiloxane copolymer, both terminal dialkylhydrogensiloxy-alkylhydrogensiloxane-dialkylsiloxane A copolymer or the like can be used.

The molecular structure of the polysiloxane having a SiH group can be used without any particular limitation, such as a linear, branched, or cyclic structure.
The weight average molecular weight of the polysiloxane having SiH groups is preferably in the range of 300 to 100,000. Further, a mixture of polysiloxanes having a weight average molecular weight of one kind or a plurality of kinds of polysiloxanes having different weight average molecular weights may be used.

The compounding amount of the polysiloxane having SiH groups is the relationship between the molar ratio of SiH groups and the molar ratio of alkenyl groups of polysiloxane having alkoxy groups and alkenyl groups in the molecule (molar ratio of SiH groups) / (mol of alkenyl groups). Ratio) = 0.8 to 2.5.
As the alkoxy-modified silicone oil, dialkylalkoxysiloxy-dialkylsiloxane at both ends, dialkylalkoxysiloxy-alkylalkoxysiloxane-dialkylsiloxane copolymer at both ends, trialkylsiloxy-alkylalkoxysiloxane-dialkylsiloxane copolymer at both ends, etc. should be used. Can do. In addition, it is preferable that the alkoxy group couple | bonded with a silicon atom has at least 2 or more in a molecule | numerator.

The molecular structure of the alkoxy-modified silicone oil can be used without any particular limitation, such as a linear or branched one.
As a method for allowing the alkoxy-modified silicone oil to be present in the elastic layer, a method of mixing a polysiloxane having no functional group other than an alkoxy group and an alkyl group in the molecule, or a polysiloxane having an alkoxy group and an alkenyl group in the molecule can be used. And a method of adding excessively to the polysiloxane having SiH groups and leaving the alkoxy-modified silicone oil in the silicone rubber component as an unreacted component.

A polysiloxane having an alkenyl group in the molecule can be used as necessary. It is preferable to have at least two alkenyl groups in the molecule. Further, as the polysiloxane having an alkenyl group bonded to a silicon atom, a dialkylalkenylsiloxy-dialkylsiloxane having both terminals, a trimethylsiloxy-alkenylalkylsiloxane-dialkylsiloxane copolymer having both terminals, and the like can be used.
The molecular structure of the polysiloxane having an alkenyl group in the molecule can be used without particular limitation, such as a linear or branched one.
A standard for the weight average molecular weight of the polysiloxane having an alkenyl group in the molecule is in the range of 500 to 2,000,000. Further, a polysiloxane having a weight average molecular weight of one kind or a mixture of plural kinds of polysiloxanes may be used.

Various carbon blacks to be blended in the elastic layer can be used without any particular limitation. For example, acetylene black having high conductivity and furnace black include SAF, ISAF, HAF, MAF, FEF, GPF, SRF and the like. The amount to be added is preferably 1% by mass to 12% by mass with respect to the elastic layer, and a more preferable range is 2% by mass to 10% by mass.

If necessary, other conductive agents can be used in combination with carbon black. For example, various conductive metals or alloys such as graphite, aluminum, copper, tin, stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, etc. Can be mentioned. The amount to be added is preferably 2% by mass to 10% by mass with respect to the mass of the elastic layer, and a more preferable range is 3% by mass to 8% by mass.

In addition, various known additives can be used. For example, reinforcing agents such as hydrophilic silica, hydrophobic silica, quartz, calcium carbonate, aluminum oxide, zinc oxide, and titanium oxide, heat transfer improvers, and the like may be added as necessary.
In order to produce the developing roller of the present invention, a known method can be used as a method of providing an elastic layer on the shaft core. For example, a method for extruding and molding the material for the shaft core and the elastic layer, and if the material is liquid, a cylindrical pipe and a piece for holding the shaft core disposed at both ends of the pipe are disposed. For example, a method of injecting into a mold and heating and curing.
The heating conditions for curing can be selected according to the curing rate of the material. Further, in order to complete the removal of low molecular components and the reaction, it can be further heated after being heated and cured. As heating conditions, it is preferable to heat at a temperature of 170 ° C to 230 ° C for 30 minutes to 8 hours.

The shaft core of the developing roller can be applied to the present invention as long as it functions as an electrode of a conductive member and a supporting member. As the material thereof, for example, a metal or alloy such as aluminum, copper, stainless steel, or iron, or a conductive material such as conductive synthetic resin is used. These materials may be plated with chrome or nickel. In addition, in order to adhere | attach the shaft core body and the elastic layer formed in the surrounding surface, a primer can be apply | coated to a shaft core body. Examples of commonly used primers include silane coupling primers.

In the developing roller of the present invention, a surface layer may be provided on the peripheral surface of the elastic layer for the purpose of providing irregularities on the surface of the developing roller.
The resin used as the surface layer can be appropriately used without particular limitation as long as it is soluble in a solvent before being cured. Specifically, fluorine resin, polyamide resin, acrylic urethane resin, phenol resin, melamine resin, silicone resin, urethane resin, polyester resin, polyvinyl acetal resin, epoxy resin, polyether resin, amino resin, acrylic resin, urea resin, etc. And mixtures thereof.

As the surface layer, a resin obtained by adding carbon black can be used. For example, carbon black having high conductivity such as ketjen black EC300J and ketjen black EC600JD (manufactured by Lion), carbon black for rubber having moderate conductivity, or carbon black for paints can be used. From the viewpoint of controlling dispersibility and conductivity, carbon black for paint is preferred. The blending amount of carbon black is preferably 3% by mass or more and 30% by mass or less with respect to the resin component.

The surface layer can be obtained by coating the elastic layer with a coating liquid in which the resin, carbon black and solvent are mixed and dispersed.
As a solvent used for a coating liquid, it can use suitably within the conditions that resin used as a surface layer melt | dissolves. Specific examples of the solvent include the following. Ketones represented by methyl ethyl ketone and methyl isobutyl ketone. Hydrocarbons represented by hexane, toluene and the like. Alcohols represented by methanol and isopropanol. Other esters. water. A particularly preferred solvent is methyl ethyl ketone (hereinafter referred to as MEK) or methyl isobutyl ketone from the solubility and boiling point of the resin. As a standard of the thickness of the surface layer, 4 μm or more and 50 μm or less is preferable, and 5 μm or more and 45 μm or less is particularly preferable.

An example of an electrophotographic apparatus used in the present invention is shown in FIG. The photosensitive drum 2 rotates at a predetermined process speed. In the process of rotating the photosensitive drum 2 at a predetermined process speed, the surface of the photosensitive drum is charged to a constant potential by a charging roller 9 having a predetermined charging bias. Further, a target electrostatic latent image is formed on the surface of the photosensitive drum 2 by image exposure (analog exposure of the original image, digital scanning exposure) by the laser light 21.
The developing roller 1 develops the electrostatic latent image on the photosensitive drum 2 to form a toner image. The paper (recording medium 24) is conveyed at a predetermined timing by the paper feed roller 22 to the transfer portion where the photosensitive drum 2 and the conveyance belt 23 are in contact with each other. Then, a transfer bias is applied to the conveyor belt 23 using a bias power source 25 and a transfer roller 26, and the toner image on the surface of the photosensitive drum 2 is transferred to paper.

The paper on which the toner image is transferred is separated from the surface of the photosensitive drum 2 and moves to the fixing device 31. The toner image is fixed on the paper by the fixing device 31, and the paper having the fixed image is discharged from the fixing device 31. . On the other hand, untransferred toner may remain on the surface of the photosensitive drum 2 after the toner image is transferred. The toner remaining without being transferred is removed from the surface of the photosensitive drum 2 by the cleaning blade 33.

The following examples further illustrate the present invention.
-Evaluation method of resistance value of developing roller and change in resistance value by energization The resistance value of the developing roller was determined by the following measuring method and calculating method of resistance value. A schematic diagram of a developing roller resistance value measuring machine is shown in FIG. The developing roller 1 was pressed against the aluminum drum 35, a load of 500 gf was applied to both ends of the shaft core of the developing roller 1, and the aluminum drum 35 was rotated so that the rotational speed of the developing roller 1 was 60 rpm. Next, a voltage of 100 V was applied to the shaft core of the developing roller 1. The drum 35 is grounded through a reference resistor 37 having a resistance value of R (Ω), and a potential difference between both ends of the reference resistor is sampled at a rate of 135 times per second using a voltmeter 38. Note that the resistance of the reference resistor 37 is sufficiently lower than the resistance value of the developing roller 1. Measurement was performed until the developing roller 1 was rotated five times, and an arithmetic average value of data for five rounds was obtained. Let the obtained value be X (V).
Current value I (A) = X (V) / R (Ω)
Therefore, the initial resistance value Z (Ω) of the developing roller was calculated as follows.
Z (Ω) = 100 (V) / I (A) = 100 (V) / X (V) × R (Ω)

Next, a test for applying a charge to the developing roller 1 for a long time was performed. The developing roller 1 is assembled in a measuring device for the resistance value of the developing roller 1, a load of 500 gf is applied to both ends of the shaft core of the developing roller 1, and the drum 35 is rotated so that the rotational speed of the developing roller 1 is 60 rpm. . In this state, at a temperature of 23 ° C., a charge was applied to the shaft core body of the developing roller so that the current value became 100 μA for 100 hours. Thereafter, as in the previous resistance value measurement of the developing roller 1, the potential difference between both ends of the reference resistance was sampled at a rate of 135 times per second. Measurement was performed until the developing roller 1 was rotated five times, and an arithmetic average value of data for five rounds was obtained. The obtained value was set as X ′ (V), and the resistance value Z ′ (Ω) of the developing roller after energization was further obtained. The value of Z ′ (Ω) / Z (Ω) is obtained from the obtained initial resistance value Z (Ω) and Z ′ (Ω) after energization, and this value is defined as a change in resistance value of the developing roller. evaluated.

A: When Z ′ (Ω) / Z (Ω) ≦ 3.0 B: When 3.0 <Z ′ (Ω) / Z (Ω) ≦ 6.0 C: 6.0 <Z ′ (Ω ) / Z (Ω) ≦ 10.0 D: 10.0 <Z ′ (Ω) / Z (Ω) In addition, the evaluation after applying the charge to the developing roller for 100 hours is 20 for the A4 size. This is equivalent to the evaluation after outputting 20000 sheets with a real machine having a printing capacity of sheets / min.

-Determination of weight average molecular weight and content of alkoxy-modified silicone oil The elastic layer was cut out, immersed in a sufficient amount of toluene, and allowed to stand at a temperature of 23 ° C for 72 hours. Toluene was removed from the toluene immersed in the elastic layer by an evaporator, and the residue was collected using gel permeation chromatography (hereinafter referred to as GPC). Furthermore, the weight average molecular weight was calculated | required by styrene conversion about the fraction which can confirm the peak which shows an alkoxy group from a nuclear magnetic resonance spectrum (henceforth NMR). Moreover, the mass of the fraction which can confirm the peak which shows an alkoxy group was measured, and content (%) of the alkoxy modified silicone oil was calculated | required from the following formula | equation.
Formula: Alkoxy-modified silicone oil content (%) = (mass of fraction from which peak showing alkoxy group can be confirmed) / (mass of cut out elastic layer) × 100

[Example 1]
A silane coupling primer: DY35-051 (trade name, Toray Dow Corning) was applied to an 8 mm diameter shaft core made of SUS304, and then baked at 170 ° C. for 20 minutes. Next, a cylindrical pipe with an inner diameter of 16 mm, and an elastic layer in which a piece for fixing the shaft core and the shaft core are assembled at both ends, and a material composed of the following contents is dispersed from the piece at one end A liquid material for forming was poured and heated at a temperature of 130 ° C. for 20 minutes. After cooling, the primary curing elastic roller 1 having a thickness of 4.0 mm was provided around the shaft core body by removing from the mold.

Material constituting the elastic layer- 83.6 parts by mass of a polysiloxane having a methoxy group and a vinyl group, the average molecular weight of which is represented by Formula 2 is 8000, and l '/ m' is 50

・式３で示されるＳｉＨ基を持つポリシロキサン ８．４質量部
（ＳｉＨ基のモル数／ビニル基のモル数＝２．０となる量）

8.4 parts by mass of polysiloxane having SiH group represented by formula 3 (amount of moles of SiH groups / moles of vinyl groups = 2.0)

・式４で示される重量平均分子量が１００００であるメトキシ変性シリコーンオイル
３質量部

A methoxy-modified silicone oil having a weight average molecular weight of 10,000 represented by formula 4
3 parts by mass

・カーボンブラック：ＨＳ−１００（商品名、電気化学工業社）
５質量部
先の一次硬化弾性ローラ１を温度２００℃で、５時間オーブンで加熱し、弾性ローラを得た。

・ Carbon black: HS-100 (trade name, Denki Kagaku Kogyo)
The primary curing elastic roller 1 at 5 parts by mass was heated in an oven at a temperature of 200 ° C. for 5 hours to obtain an elastic roller.

Next, a surface layer was provided on the peripheral surface of the elastic layer roller as follows. That is,
Polyol: N5120 (trade name, Nippon Polyurethane) 87 parts by mass Isocyanate: L-55E (trade name, Nippon Polyurethane) 13 parts by mass Carbon black: MA77 (trade name, Mitsubishi Chemical) 20 parts by mass Acrylic particles : G-800 transparent (trade name, Negami Kogyo Co., Ltd.) 20 parts by mass were weighed, MEK was added, and the well-stirred mixture was placed in an overflow-type circulation coating apparatus. The elastic layer roller was immersed in the coating device and pulled up, and then air-dried for 60 minutes, and then heated at 160 ° C. for 5 hours to provide a surface layer. The obtained developing roller was evaluated for change in resistance value after energization, the value of l / m by ¹³ C NMR measurement, and the content of alkoxy-modified silicone oil by toluene extraction and fractionation using GPC. The results are shown in Table 1.

Next, another developing roller that has not been evaluated for changes in resistance or the like is incorporated into a cartridge for a color laser printer: LBP5500 (trade name, Canon Inc.), and an image having the following image pattern is output using the laser printer. The ghost performance was evaluated. (Hereinafter referred to as initial ghost evaluation.) By outputting 20000 sheets of images over 100 hours, the printer was operated until there was no toner in the cartridge. The following ghost performance evaluation image patterns were output to evaluate the ghost performance. (Hereinafter referred to as ghost evaluation after endurance)

Image pattern for evaluating ghost performance Six square solid images with a side of 20 mm are lined up horizontally on the top of one sheet of paper, and an image with a half-tone pattern underneath it. Two types of image patterns with different tone densities were used, one for each and two in total. A halftone having a density measured using a spectral densitometer (manufactured by X-Rite Inc: 504 spectral densitometer) indicating 0.4 and 0.7 was used.

-Ghost performance evaluation A: In the ghost evaluation after endurance, when no negative ghost having a square shape with a side of 20 mm is seen on the halftone of both image patterns. B: In the ghost evaluation after endurance, A square negative ghost with a side of 20 mm can be confirmed on the halftone, but at a level where there is no problem in actual use. C: In a ghost evaluation after endurance, a square with a side of 20 mm on the halftone of both image patterns In case of a level where there is no problem in actual use D: In the ghost evaluation after endurance, a square negative ghost with a side of 20 mm can be clearly confirmed on both halftones, and there is a problem even in actual use At a certain level

[Example 2]
Example 1 except that polysiloxane having a methoxy group and a vinyl group having a weight average molecular weight of 15000 and l ′ / m ′ of 40 and a methoxy modified silicone oil having a weight average molecular weight of 8000 were used. went. The results are shown in Table 1.
Example 3
The same procedure as in Example 1 was conducted except that a polysiloxane having an ethoxy group and a vinyl group having a weight average molecular weight of 15000 and l ′ / m ′ of 40 and an ethoxy-modified silicone oil were used. The results are shown in Table 1.

Example 4
The same procedure as in Example 1 was conducted except that polysiloxane having an ethoxy group and a vinyl group and an ethoxy-modified silicone oil having a weight average molecular weight of 8000 were used. The results are shown in Table 1.
Example 5
41.8% by mass of a polysiloxane having a methoxy group and a vinyl group having l ′ / m ′ of 25, 41.8% by mass of a polysiloxane having a vinyl group having a weight average molecular weight of 8,000 represented by the formula 5, and ethoxy modification The same procedure as in Example 1 was performed except that silicone oil was used. The results are shown in Table 1.

Example 6
41.8% by mass of a polysiloxane having a methoxy group and a vinyl group having an average molecular weight of 15000 and l ′ / m ′ of 20, and a polysiloxane having a vinyl group having a weight average molecular weight of 15000 represented by Formula 5 The same procedure as in Example 1 was performed except that ethoxy-modified silicone oil having a weight average molecular weight of 8000 mass% was used. The results are shown in Table 1.

Example 7
41.8% by mass of polysiloxane having an ethoxy group and a vinyl group having an average molecular weight of 15000 and l ′ / m ′ of 20, and a polysiloxane having a vinyl group having a weight average molecular weight of 100,000 represented by formula 6 The same procedure as in Example 1 was performed except that% by mass was used. The results are shown in Table 1.

Example 8
41.8% by mass of a polysiloxane having an ethoxy group and a vinyl group in which l ′ / m ′ is 25, 41.8% by mass of a polysiloxane having a vinyl group having a weight average molecular weight of 100,000 represented by formula 6, The same procedure as in Example 1 was performed except that a methoxy-modified silicone oil having a weight average molecular weight of 8000 was used. The results are shown in Table 1.
Example 9
The same procedure as in Example 1 was performed except that polysiloxane having an i-pentoxy group and vinyl group having an average molecular weight of 15000 and a methoxy-modified silicone oil having a weight average molecular weight of 8000 was used. The results are shown in Table 1.

Example 10
The same procedure as in Example 1 was performed except that polysiloxane having a methoxy group and a vinyl group having l ′ / m ′ of 65 and a methoxy-modified silicone oil having a weight average molecular weight of 8000 were used. The results are shown in Table 2.
Example 11
The same procedure as in Example 1 was conducted except that polysiloxane having an ethoxy group and a vinyl group having l ′ / m ′ of 65 and an ethoxy-modified silicone oil having a weight average molecular weight of 3000 were used. The results are shown in Table 2.

Example 12
The same procedure as in Example 1 was performed except that polysiloxane having an ethoxy group and a vinyl group having a weight average molecular weight of 5000 and a methoxy-modified silicone oil having a weight average molecular weight of 3000 were used. The results are shown in Table 2.
Example 13
A polysiloxane represented by Formula 7 having an ethoxy group and a vinyl group having l '/ m' of 40 and having weight average molecular weights of 1000 and 150,000, and an ethoxy-modified silicone oil having a weight average molecular weight of 3000 are used. The procedure was the same as in Example 1 except for the above. The results are shown in Table 2.

Example 14
The same procedure as in Example 1 was performed except that the polysiloxane represented by Formula 8 having an ethoxy group and a vinyl group and an ethoxy-modified silicone oil having a weight average molecular weight of 2000 were used. The results are shown in Table 2.

Example 15
The polysiloxane represented by the formula 7 having an ethoxy group and a vinyl group and having a weight average molecular weight of 8000 and 100,000 and the SiH group-containing cyclic polysiloxane represented by the formula 9 were used. The same procedure as in Example 1 was performed except that 5% by mass was added. The results are shown in Table 2.

Example 16
a polysiloxane having a methoxy group and a vinyl group having l ′ / m ′ of 40 and having weight average molecular weights of 5000 and 15000 and a SiH group-containing cyclic polysiloxane represented by formula 9; The same procedure as in Example 1 was performed except that 0.5% by mass of silicone oil was added. The results are shown in Table 2.
Example 17
The same procedure as in Example 1 was performed except that polysiloxane having an ethoxy group and a vinyl group and a SiH group-containing cyclic polysiloxane represented by Formula 9 were used, and that 6% by mass of ethoxy-modified silicone oil was added. The results are shown in Table 2.

Example 18
Use of a polysiloxane having a methoxy group and a vinyl group having a weight average molecular weight of 15000 and l ′ / m ′ of 40, and a SiH group-containing cyclic polysiloxane represented by formula 9, and 6% by mass of methoxy-modified silicone oil Except for the addition, the same procedure as in Example 1 was performed. The results are shown in Table 2.

[Comparative Example 1]
In place of polysiloxane having methoxy group and vinyl group, polysiloxane having vinyl group bonded to silicon atom having a weight average molecular weight of 100,000 shown in formula 6 was used, and alkoxy-modified silicone oil was not used. The other operations were performed in the same manner as in Example 1. The results are shown in Table 3.
[Comparative Example 2]
The same procedure as in Example 1 was conducted except that dimethyl silicone oil was used instead of methoxy modified silicone oil. The results are shown in Table 3.

[Comparative Example 3]
The same procedure as in Example 1 was carried out except that a polysiloxane having a vinyl group having a weight average molecular weight of 100,000 shown in Formula 6 was used instead of the polysiloxane having a methoxy group and a vinyl group. The results are shown in Table 3.
[Comparative Example 4]
The use of a polysiloxane having a vinyl group with a weight average molecular weight of 100,000 shown in Formula 6 instead of a polysiloxane having a methoxy group and a vinyl group, and the use of dimethyl silicone oil instead of an alkoxy-modified silicone oil The other operations were performed in the same manner as in Example 1. The results are shown in Table 3.

In addition, although the resistance value change and negative ghost performance of Comparative Examples 1 and 4 were the same D rank as compared with Comparative Examples 2 and 3, they were clearly inferior.
In Examples 1 to 18, the elastic layer is composed of silicone rubber obtained by crosslinking alkoxy-modified polysiloxane and alkoxy-modified silicone oil. Therefore, the resistance value hardly changed during use as a developing roller. On the other hand, in Comparative Example 1, the elastic layer is made of silicone rubber obtained by crosslinking polysiloxane that is not alkoxy-modified. Therefore, the resistance value increased during use as a developing roller, and the negative ghost performance deteriorated. In Comparative Example 2, silicone oil that was not alkoxy-modified was used. Therefore, during use as a developing roller, the resistance value increased and the negative ghost performance deteriorated. In Comparative Example 3, a silicone rubber obtained by crosslinking polysiloxane which is not alkoxy-modified is used. Therefore, the resistance value increased during use as a developing roller, and the negative ghost performance deteriorated. In Comparative Example 4, the elastic layer is composed of silicone rubber obtained by crosslinking polysiloxane that is not alkoxy-modified and silicone oil that is not alkoxy-modified. Therefore, the resistance value increased during use as a developing roller, and the negative ghost performance deteriorated.

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Photosensitive drum 3 Hopper 4 Toner 5 Stirring blade 6 Toner supply roller 7 Developing bias power supply 8 Toner regulating blade 9 Charging roller 10 Developing devices 10a to 10d Developing devices (for each color)
21 Laser beam 22 Feed roller 23 Conveyor belt 24 Recording medium 25 Bias power supply 26 Transfer roller 27 Drive roller 28 Drive roller 29 Tension roller 30 Adsorption roller 31 Fixing device 32 Peeling device 33 Cleaning blade 34 Waste toner container 35 Aluminum drum 36 Resin Drum 37 Reference resistance 38 Voltmeter

Claims (6)

A developing roller having a shaft core and an elastic layer provided on the outer periphery of the shaft core,
The elastic layer is
Silicone rubber obtained by crosslinking alkoxy-modified polysiloxane;
Alkoxy-modified silicone oil;
A developing roller characterized by containing carbon black. The developing roller according to claim 1 , wherein the alkoxy-modified silicone oil has a weight average molecular weight of 3000 or more and 20000 or less. Silicone rubber obtained by crosslinking the alkoxy-modified polysiloxane is
The developing roller according to claim 1, wherein the developing roller has a structure represented by the following formula (1), and l and m are 1 / m ≦ 120.

(In the above formula (1), R ¹ , R ² , R ³ and R ⁴ are hydrocarbons having 1 to 5 carbon atoms, which may be the same or different). The developing roller according to any one of claims 1 to 3, wherein the content of the alkoxy-modified silicone oil is 0.5 % by mass or more and 6.0% by mass or less with respect to the mass of the elastic layer.   The developing roller according to claim 1, wherein the amount of carbon black added is 1% by mass or more and 12% by mass or less with respect to the elastic layer.   An electrophotographic apparatus having an electrophotographic photosensitive member and a developing roller in contact with the electrophotographic photosensitive member, wherein the developing roller is the developing roller according to any one of claims 1 to 5. A feature of an electrophotographic apparatus.

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