JP2011085656A - Cleaning blade for image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning blade for an image forming device capable of showing over a long period, excellent cleaning performance fit to a linear pressure, when bringing an edge part into slide-contact with the surface with a high linear pressure fit to cleaning of especially a small particle size toner or a spherical toner in the contact state with the surface of a photoreceptor. <P>SOLUTION: The cleaning blade 22 for the image forming device is formed by using an elastomer composition including a rubber portion containing XNBR and/or HXNBR at the rate of 70 mass% or more, a crosslinking agent, and zinc oxide as much as 20 pts.mass or more per 100 pts.mass of the rubber portion in total and 45 mass% or less of the amount of XNBR and/or HXNBR. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cleaning blade for an image forming apparatus used in an image forming apparatus such as an electrostatic copying machine, a laser printer, a plain paper facsimile machine, and a complex machine of these.

  In the image forming apparatus, the surface of the photoconductive photoconductor is exposed in a uniformly charged state to form an electrostatic latent image corresponding to the formed image on the surface (charging process → exposure process). ) After the electrostatic latent image is developed into a toner image by selectively adhering a pre-charged toner (development process), the surface of the toner image (including a plastic film, etc.) (Transfer process), and further fixing (fixing process), an image is formed on the surface of the paper. The surface of the photoreceptor after the toner image is transferred to the surface of the paper is used for the next image formation after the toner remaining in the cleaning process is removed.

As toner,
(a) A pulverized toner produced by pulverizing a kneaded product containing a fixing resin, a colorant, etc., and further classifying as necessary, or
(b) A spherical shape produced by polymerizing the monomers and the like in a state where a mixture of monomers or oligomers, a polymerization initiator, a colorant, and the like as a fixing resin is dispersed in a minute spherical shape in a dispersion medium. A deformed polymer toner obtained by further deforming a polymerized toner by compression deformation or the like is widely used.

In the cleaning process, for example, a rectangular flat plate is formed, and the toner remaining on the surface is peeled off by sliding on the surface in a state where an edge portion of one side of the rectangle is in contact with the surface of the photoreceptor. It is common to use a cleaning blade that is removed in this manner.
The pulverized toner and the modified polymerized toner can be sufficiently cleaned even if the contact pressure (linear pressure) of the edge portion of the cleaning blade to the surface of the photoreceptor is low.

  Therefore, as a cleaning blade, since the heat resistance, wear resistance, etc. are low in the past, the edge portion is worn in a relatively short period of time due to friction with the photoconductor when exposed to a high temperature particularly during operation of the image forming apparatus. Although there is a problem that the function of removing the toner is likely to deteriorate, the toner attached to the surface of the photoconductor is scraped off or blown off efficiently without causing the surface of the photoconductor to be worn or damaged as much as possible. In consideration of making it possible to remove the material, a flexible urethane rubber material has been widely used.

  However, in recent years, in order to further reduce the energy consumption, cost, and quality of the formed image, the image forming apparatus can be used in the form of a sphere without reducing the particle size of the toner or by changing the shape of the polymerized toner. In order to prevent the occurrence of poor cleaning by reliably removing the small particle size toner and spherical toner from the surface of the photoconductor, it is necessary to increase the linear pressure at the edge portion more than the current state. Has arisen.

However, conventional urethane rubber cleaning blades are not sufficiently heat-resistant and wear-resistant as described above, and the edge portions are likely to wear, so it is substantially difficult to increase the linear pressure from the current level.
Therefore, recently, in order to provide a cleaning blade that is excellent in heat resistance and wear resistance and is particularly difficult to wear at the edge portion, it is possible to provide a cleaning blade capable of increasing the linear pressure and improving the cleaning performance for small particle size toner and spherical toner. Various forming materials have been studied.

  For example, in Patent Documents 1 to 3, the cleaning blade may be abbreviated as hydrogenated acrylonitrile butadiene rubber (hereinafter may be abbreviated as “HNBR”) or carboxylated acrylonitrile butadiene rubber (hereinafter “XNBR”). Or an elastomer composition containing any one NBR rubber among hydrogenated carboxylated acrylonitrile butadiene rubbers (hereinafter sometimes abbreviated as “HXNBR”).

Specifically, the cleaning blade is manufactured by molding an elastomer composition containing the rubber component, a crosslinking agent thereof, a filler, and the like into a predetermined shape of the cleaning blade and reinforcing the rubber component by crosslinking.
As the crosslinking agent, sulfur, an organic sulfur-containing compound, a peroxide crosslinking agent, or the like is used. Among these, when using sulfur, in the Example of patent documents 1-3, all contain 1.5 mass parts of sulfur per 100 mass parts of rubber components.

  Further, in a system using XNBR or HXNBR as a rubber component, the elastomer composition may contain zinc oxide, zinc (meth) acrylate, or the like. The zinc oxide or the like functions as a co-crosslinking agent that further ionizes the carboxyl group in the XNBR and HXNBR and further reinforces the rubber component crosslinked by the crosslinking agent.

JP 2008-107754 A JP 2008-299204 A JP 2009-186828 A

However, according to the inventor's study, although the cleaning blades of the inventions described in Patent Documents 1 to 3 are all improved in wear resistance as compared with those made of conventional urethane rubber, such wear resistance is improved. It has been clarified that even if it is used for cleaning with increased linear pressure at the edge portion, good cleaning performance commensurate with the increased linear pressure cannot be exhibited.
The object of the present invention is to make the line contact when the surface is slid on the surface in a state where the edge portion is in contact with the surface of the photoreceptor with a high linear pressure suitable for cleaning a small particle size toner or a spherical toner. An object of the present invention is to provide a cleaning blade for an image forming apparatus that can exhibit good cleaning performance commensurate with pressure over a long period of time.

The present invention is an image forming apparatus cleaning blade comprising an elastomer composition, the elastomer composition as a rubber component,
(1-1) at least one rubber selected from the group consisting of carboxylated acrylonitrile butadiene rubber and hydrogenated carboxylated acrylonitrile butadiene rubber; or
(1-2) A mixed rubber comprising the rubber (1-1) and a hydrogenated acrylonitrile butadiene rubber, wherein the amount of the rubber (1-1) in the total amount of both is 70% by mass or more ,
Any one of and
(2) a crosslinking agent, and
(3) Zinc oxide that is 20 parts by mass or more per 100 parts by mass of the total rubber content and 45% by mass or less of the amount of the rubber of (1-1),
It is characterized by including.

The conventional cleaning blade cannot exhibit a good cleaning performance commensurate with a predetermined linear pressure because the edge portion brought into contact with the surface of the photoconductor with the predetermined linear pressure is in contact with the rotation of the photoconductor. One of the causes is considered to be a so-called slip-stick behavior when slid on the surface.
That is, the cleaning blade does not slide smoothly while maintaining a fixed shape with respect to the surface of the photosensitive member, and the edge portion follows the surface by a frictional force (stick) as it moves relative to the surface. ) Gradually deform, and with this deformation, the internal stress of the cleaning blade increases and exceeds the frictional force, causing slippage (slip) with respect to the surface to restore the original shape to some extent Repeat the operation to vibrate.

When the vibration occurs, the linear pressure may decrease or the edge portion may be separated from the surface of the photoconductor. At this time, the toner adhering to the surface of the photoconductor passes through the cleaning blade without being removed. As a result, slipping of the toner occurs, and the cleaning performance deteriorates.
On the other hand, according to the present invention, a cleaning blade for an image forming apparatus comprising the elastomer composition can be obtained by containing a large amount of zinc oxide of 20 parts by mass or more per 100 parts by mass of the total rubber content in the elastomer composition. The specific gravity can be increased to suppress the vibration of the edge portion, and the toner can be prevented from slipping through the vibration.

Further, since the zinc oxide functions as a co-crosslinking agent to reinforce the rubber component by ionic bond with the carboxyl group contained in XNBR and / or HXNBR of (1-1) in the rubber component, By containing this zinc oxide, the abrasion resistance of the image forming apparatus cleaning blade can be improved.
Therefore, according to the present invention, when the edge portion is in contact with the surface of the photosensitive member with a high linear pressure particularly suitable for cleaning a small particle size toner or a spherical toner, It is possible to provide a cleaning blade for an image forming apparatus that can exhibit a good cleaning performance corresponding to the linear pressure over a long period of time.

  In the present invention, the amount of XNBR and / or HXNBR in the total amount of rubber is limited to 70% by mass or more when the amount is less than the above range, the number of ion bonding points (carboxyl groups) with zinc oxide decreases. This is because the sufficient effect of ionic bonding cannot be obtained and the excess zinc oxide that is not ion-bonded to the carboxyl group tends to fall off, resulting in a decrease in wear resistance of the cleaning blade for the image forming apparatus. .

In particular, the zinc oxide is dropped off at the edge portion, so that the edge portion is likely to be chipped, and the toner is easily slipped at the chipped portion, so that the cleaning performance is deteriorated.
In the present invention, the amount of zinc oxide is limited to 45% by mass or less of the amount of (1-1) XNBR and / or HXNBR. Excess zinc oxide exceeding the above range is not ionically bonded to the carboxyl group. Therefore, it is easy to fall off, and the wear resistance of the image forming apparatus cleaning blade is reduced.

In particular, the zinc oxide is dropped off at the edge portion, so that the edge portion is likely to be chipped, and the toner is easily slipped at the chipped portion, so that the cleaning performance is deteriorated.
HNBR is preferably HNBR hydrogenated so that the residual double bond amount is 3% or more and 10% or less. If the amount of residual double bonds is less than the above range, the crosslinking density of the rubber can be sufficiently increased even if a crosslinking reaction (crosslinking reaction between the double bond in the rubber and the crosslinking agent) is performed with a predetermined amount of the crosslinking agent. Therefore, the wear resistance of the image forming apparatus cleaning blade may be reduced. On the other hand, when the above range is exceeded, the mechanical strength as rubber is lowered, and the wear resistance of the image forming apparatus cleaning blade may be lowered.

The cross-linking agent is preferably sulfur, and the elastomer composition preferably contains the sulfur in a range of less than 2.5 parts by mass per 100 parts by mass of the total rubber content.
It is preferable that the amount of sulfur is 2.5 parts by mass or less, in addition to the rubber component cross-linked at a relatively high density with sulfur exceeding the above range, an ion-bonded structure with a large amount of zinc oxide is further introduced. This is because the cured image forming apparatus cleaning blade is hard and brittle, and its wear resistance may decrease.

  According to the present invention, when the edge portion is brought into contact with the surface of the photosensitive member with a high linear pressure particularly suitable for cleaning a small particle size toner or a spherical toner, the line is slid on the surface. It is possible to provide a cleaning blade for an image forming apparatus that can exhibit good cleaning performance commensurate with pressure over a long period of time.

1 is a schematic cross-sectional view of an example of an image forming apparatus that can incorporate a cleaning blade for an image forming apparatus of the present invention. It is sectional drawing which expands and shows the part of the cleaning blade for image forming apparatuses among the image forming apparatuses of the said example. It is a figure for demonstrating the measuring method of the dimension of the wear surface which arose in the edge part in the abrasion test which evaluates the abrasion resistance of the cleaning blade for image forming apparatuses produced by the Example of this invention and the comparative example.

The present invention is an image forming apparatus cleaning blade comprising an elastomer composition, the elastomer composition as a rubber component,
(1-1) at least one rubber selected from the group consisting of carboxylated acrylonitrile butadiene rubber and hydrogenated carboxylated acrylonitrile butadiene rubber; or
(1-2) A mixed rubber comprising the rubber (1-1) and a hydrogenated acrylonitrile butadiene rubber, wherein the amount of the rubber (1-1) in the total amount of both is 70% by mass or more ,
Any one of and
(2) a crosslinking agent, and
(3) Zinc oxide that is 20 parts by mass or more per 100 parts by mass of the total rubber content and 45% by mass or less of the amount of the rubber of (1-1),
It is characterized by including.

  XNBR can be prepared by copolymerizing acrylic acid or methacrylic acid as a third component together with acrylonitrile and butadiene constituting the main chain of acrylonitrile butadiene rubber (hereinafter sometimes abbreviated as “NBR”). Examples thereof include various XNBRs having a carboxyl group introduced into the chain. Moreover, as HXNBR, various HXNBR which hydrogenated the double bond contained in the butadiene part of the principal chain of said XNBR is mentioned.

  The content of carboxyl groups in the XNBR and HXNBR is preferably 0.5% by mass or more, particularly preferably 10% by mass or more, and is preferably 30% by mass or less, particularly preferably 20% by mass or less. If the carboxyl group content is less than the above range, a sufficient reinforcing effect due to the function of the carboxyl group as an ionic bond point with zinc oxide cannot be obtained, and the wear resistance of the image forming apparatus cleaning blade may be reduced. There is. When the above range is exceeded, the reactivity of XNBR and HXNBR becomes too high and so-called rubber burns are likely to occur, and when the rubber burns occur, the wear resistance of the cleaning blade for the image forming apparatus decreases. There is a fear.

  XNBR and HXNBR preferably have a combined acrylonitrile content of 21% or more, preferably 46% or less, particularly preferably 44% or less. If the amount of bound acrylonitrile is less than the above range, the mechanical strength of the XNBR and HXNBR itself is insufficient, and the wear resistance of the image forming apparatus cleaning blade may be reduced. When the above range is exceeded, the glass transition temperature Tg of the XNBR and HXNBR itself becomes high, so that the cleaning blade for an image forming apparatus may become hard, particularly in a low temperature environment, and the cleaning performance may be deteriorated.

  XNBR and HXBNR have a Mooney viscosity, which indicates their molecular weight, of 20 ML (1 + 4) 100 ° C. or higher, preferably 40 ML (1 + 4) 100 ° C. or higher, 160 ML (1 + 4) 100 ° C. or lower, particularly 150 ML (1 + 4) 100 ° C. It is preferable that: XNBR and HXNBR with a small molecular weight whose Mooney viscosity is less than the above range have insufficient mechanical strength, which may reduce the wear resistance of the image forming apparatus cleaning blade. Further, since XNBR and HXNBR having a large molecular weight exceeding the above range are not easily kneaded or molded, the productivity of the cleaning blade for an image forming apparatus may be lowered.

  HXNBR has a residual double bond content of 3% or more, particularly 3.5% or more, preferably 10% or less, particularly preferably 9% or less. If the amount of residual double bonds is less than the above range, the crosslinking density of the rubber cannot be sufficiently increased even if the crosslinking reaction is performed with a predetermined amount of the crosslinking agent, and the wear resistance of the cleaning blade for the image forming apparatus may be reduced. There is. On the other hand, when the above range is exceeded, the mechanical strength as rubber is lowered, and the wear resistance of the image forming apparatus cleaning blade may be lowered.

Examples of the XNBR include various XNBRs of the KRYNAC (Clinac, registered trademark) series manufactured by LANXESS, Germany. Moreover, as HXNBR, various HXNBRs of THERBAN (registered trademark) series also manufactured by LANXESS are listed.
Examples of HNBR include various HNBRs in which double bonds contained in the butadiene portion of the main chain of NBR are hydrogenated.

  HNBR preferably has a bound acrylonitrile content of 21% or more, preferably 46% or less, particularly preferably 44% or less. If the amount of bound acrylonitrile is less than the above range, the mechanical strength of the HNBR itself may be insufficient, and the wear resistance of the image forming apparatus cleaning blade may be reduced. In addition, when the above range is exceeded, the glass transition temperature Tg of the HNBR itself becomes high, and the cleaning blade for the image forming apparatus may become hard, particularly in a low temperature environment, and the cleaning performance may be deteriorated.

  HBNR has a Mooney viscosity indicating its molecular weight of 20 ML (1 + 4) 100 ° C. or higher, preferably 40 ML (1 + 4) 100 ° C. or higher, 160 ML (1 + 4) 100 ° C. or lower, particularly 150 ML (1 + 4) 100 ° C. or lower. Preferably there is. HNBR with a small molecular weight whose Mooney viscosity is less than the above range has insufficient mechanical strength, which may reduce the wear resistance of the image forming apparatus cleaning blade. Further, HNBR having a large molecular weight exceeding the above range is not easy to knead or mold, and thus there is a risk that the productivity of the cleaning blade for an image forming apparatus is lowered.

  Further, HNBR has a residual double bond amount of 3% or more, particularly 3.5% or more, preferably 10% or less, particularly preferably 9% or less. If the amount of residual double bonds is less than the above range, the crosslinking density of the rubber cannot be sufficiently increased even if the crosslinking reaction is performed with a predetermined amount of the crosslinking agent, and the wear resistance of the cleaning blade for the image forming apparatus may be reduced. There is. On the other hand, when the above range is exceeded, the mechanical strength as rubber is lowered, and the wear resistance of the image forming apparatus cleaning blade may be lowered.

In the present invention, as described above,
(1-1) at least one rubber selected from the group consisting of carboxylated acrylonitrile butadiene rubber and hydrogenated carboxylated acrylonitrile butadiene rubber; or
(1-2) A mixed rubber comprising the rubber (1-1) and a hydrogenated acrylonitrile butadiene rubber, wherein the amount of the rubber (1-1) in the total amount of both is 70% by mass or more ,
One of these is used.

  In the combined system (1-2), the amount of XNBR and / or HXNBR is limited to 70% by mass or more of the total amount of the rubber component. ), The reinforcing effect due to ionic bonds cannot be obtained sufficiently, and excess zinc oxide that is not ion-bonded to carboxyl groups tends to fall off, and the wear resistance of the cleaning blade for an image forming apparatus is reduced. It is because it falls.

In particular, the zinc oxide is dropped off at the edge portion, so that the edge portion is likely to be chipped, and the toner is easily slipped at the chipped portion, so that the cleaning performance is deteriorated.
In consideration of further improving the reinforcing effect by ionic bonding with zinc oxide and further improving the wear resistance and cleaning performance of the cleaning blade for image forming apparatus, the amount of XNBR and / or HXNBR is Even within the range, it is preferably 90% by mass or more.

The upper limit of the amount of XNBR and / or HXNBR is 100% by mass. That is, as described in (1-1), the present invention includes a case where only XNBR and / or HXNBR is used and HNBR is not included.
Considering the effect of improving the wear resistance of the cleaning blade for the image forming apparatus, the amount of XNBR and / or HXNBR is preferably larger within the above range as described above, but a cheaper HNBR is blended within the above range. Thus, the cost of the image forming apparatus cleaning blade can be reduced without degrading the cleaning performance.

  The amount of zinc oxide as a co-crosslinking agent is limited to 20 parts by mass or more per 100 parts by mass of the total rubber content. If the amount is less than the above range, the edge of the image forming apparatus is increased by increasing the specific gravity. This is because the effect of suppressing the vibration of the portion and suppressing the slipping of the toner due to the vibration cannot be obtained. Further, this is because a sufficient effect of reinforcing the rubber component cannot be obtained by ionic bonding with a carboxyl group contained in XNBR and / or HXNBR, and the wear resistance of the image forming apparatus cleaning blade cannot be sufficiently improved.

  In addition, the amount of zinc oxide is limited to 45% by mass or less of the amount of XNBR and / or HXNBR. Excess zinc oxide exceeding the above range is not ion-bonded to the carboxyl group, and thus is easily dropped off. This is because the wear resistance of the cleaning blade is reduced. In particular, the zinc oxide is dropped off at the edge portion, so that the edge portion is likely to be chipped, and the toner is easily slipped at the chipped portion, so that the cleaning performance is deteriorated.

  In addition, the amount of zinc oxide is effective to suppress the vibration of the edge part by increasing the specific gravity of the cleaning blade for the image forming apparatus while preventing the above-mentioned dropout problem more reliably, and the ion bond reaction with the carboxyl group. In view of further improving the effect of reinforcing the rubber content, the amount is preferably 25 parts by mass or more, more preferably 35 parts by mass or less per 100 parts by mass of the total rubber content even within the above range.

  It is preferable that the amount of sulfur as a crosslinking agent is less than 2.5 parts by mass per 100 parts by mass of the total rubber content. Furthermore, when the ion binding structure with a large amount of zinc oxide is introduced, the cured cleaning blade for an image forming apparatus becomes hard and brittle, so that its wear resistance may be lowered.

In consideration of further improving the wear resistance, the amount of sulfur is preferably 1 part by mass or more and preferably 2 parts by mass or less per 100 parts by mass of the total amount of rubber even within the above range. .
In addition, as a crosslinking agent, it may replace with the said sulfur and may use an organic sulfur compound, an organic peroxide, a heat resistant crosslinking agent, a resin crosslinking agent etc., for example. The amount of the other cross-linking agent is such that when the ionic bond structure by a large amount of zinc oxide is further introduced into the rubber component cross-linked by the respective cross-linking agent, the cleaning blade for the image forming apparatus after curing is hard and What is necessary is just to set to the arbitrary ranges which become weak and there is no possibility that the abrasion resistance may fall on the contrary.

  The elastomer composition may further contain a filler. Examples of the filler include silicates such as carbon black, silica, magnesium silicate, calcium carbonate, tansan magnesium, magnesium silicate, clay, talc, coumarone indene resin powder, phenol resin powder, wood powder and the like. The seed | species or 2 or more types is mentioned, Especially carbon black and / or a silica are preferable.

The amount of the filler is preferably 5 parts by mass or more, particularly 10 parts by mass or more, preferably 35 parts by mass or less, particularly 30 parts by mass or less, per 100 parts by mass of the total amount of the rubber.
By including the amount of the filler, it is possible to further enhance the reinforcement effect by the crosslinking described above and ion binding by zinc oxide, and further improve the wear resistance of the cleaning blade for an image forming apparatus.

  If the amount of the filler is less than the above range, the reinforcing effect due to the inclusion of the filler may not be sufficiently obtained. In addition, for example, after forming and crosslinking an elastomer composition, there is a possibility that the workability when processing (cutting, punching, etc.) into a predetermined shape of a cleaning blade for an image forming apparatus may be lowered. On the other hand, when the above range is exceeded, the reinforcing effect of the filler is weakened, and the wear resistance of the image forming apparatus cleaning blade may be reduced.

  As the carbon black, any of various grades of carbon black used as a rubber filler and a reinforcing agent can be used. Examples of the carbon black include SAF, SAF-HS, ISAF, N-339, ISAF-LS, ISAF-HS, HAF, HAF-HS, N-351, HAF-LS, LI-HAF, MAF, FEF, and SRF. , SRF-LM, GPF or the like.

As the silica, any of various types of silica used as a rubber filler and a reinforcing agent among wet silica and dry silica classified according to the production method can be used.
When silica is used as the filler, it is preferable to add a coupling agent such as a silane coupling agent in order to increase the affinity of the silica for rubber. The amount of the coupling agent is preferably about 6 parts by mass or more and 12 parts by mass or less per 100 parts by mass of silica.

It is preferable that the elastomer composition further contains a vulcanization accelerator. Examples of the vulcanization accelerator include one or more of thiazole vulcanization accelerator, thiuram vulcanization accelerator, thioureas, dithiocarbamates, guanidines, sulfenamides, etc. Thiazole vulcanization accelerators and / or thiuram vulcanization accelerators are preferred.
These vulcanization accelerators function to promote the cross-linking reaction between the double bond in the rubber component and the cross-linking agent (especially sulfur) and the ionic bond reaction between the carboxyl group in the rubber component and zinc oxide. Therefore, the wear resistance of the image forming apparatus cleaning blade can be further improved.

  Examples of thiazole-based vulcanization accelerators include M [2-mercaptobenzothiazole, MBT], DM [dibenzothiazyl disulfide, MBTS], MZ [zinc salt of 2-mercaptobenzothiazole, ZnMBT], HM [2-mercapto. One or more of cyclohexylamine salt of benzothiazole, CMBT], DS [2- (4′-morpholinodithio) benzothiazole, MDB] and the like can be mentioned, and DM is particularly preferable.

  Examples of the thiuram vulcanization accelerator include TT [tetramethylthiuram disulfide, TMTD], TET [tetraethylthiuram disulfide, TETD], TBT [tetrabutylthiuram disulfide, TBTD], TS [tetramethylthiuram monosulfide, TMTM]. , TRA [dipentamethylene thiuram tetrasulfide, DPTT] and the like, and TS is particularly preferable.

The thiazole vulcanization accelerator and the thiuram vulcanization accelerator are preferably used in combination since they have different vulcanization acceleration mechanisms. In particular, DM and TS are used in combination with the above-described cross-linking reaction between the double bond in the rubber component and the cross-linking agent (especially sulfur) and the ionic bond reaction between the carboxyl group in the rubber component and zinc oxide. It is suitable in terms of the effect of promoting the above.
When sulfur is used as the cross-linking agent, the amount of thiazole vulcanization accelerator such as DM is preferably ½ part by weight or more and 3/2 parts by weight or less per 1 part by weight of sulfur. The amount of the vulcanization accelerator is preferably ¼ part by weight or more and 1 part by weight or less per part by weight of sulfur.

When the amount of the vulcanization accelerator is less than the above range, unreacted sulfur may bloom on the surface of the cleaning blade for the image forming apparatus after crosslinking. When the amount exceeds the above range, the image forming apparatus after crosslinking is over. The surplus vulcanization accelerator may bloom on the surface of the cleaning blade.
The elastomer composition may further contain a vulcanization accelerating aid, an anti-aging agent, a rubber softener and the like in addition to the above-described components.

Among these, examples of the vulcanization acceleration aid include one or more of metal oxides such as zinc oxide, fatty acids such as stearic acid, oleic acid and cottonseed fatty acid, and other various vulcanization acceleration aids. Zinc oxide can also be used as a co-crosslinking agent as described above. The amount of the vulcanization acceleration aid is preferably 30 parts by mass or less per 100 parts by mass of rubber.
Examples of the antiaging agent include one or more of amines, phenols, imidazoles, phosphoric acids, thioureas, and the like. The amount of the anti-aging agent is preferably 0.1 parts by mass or more, particularly 0.5 parts by mass or more, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less, per 100 parts by mass of rubber.

Examples of rubber softeners include one or more of phthalic acid derivatives, isophthalic acid derivatives, adipic acid derivatives, sebacic acid derivatives, benzoic acid derivatives, phosphoric acid derivatives, and the like. The amount of the softening agent for rubber is preferably 5 parts by mass or less per 100 parts by mass of rubber.
In order to adjust the elastomer composition, for example, a rubber component is kneaded under heating using a kneader such as a twin-screw extruder, open roll, Banbury mixer, kneader, etc., and then a filler is first added while continuing the kneading, After the filler is sufficiently dispersed in the rubber component, zinc oxide, a vulcanization accelerator, a vulcanization acceleration aid, an antiaging agent, and the like are added and further kneaded.

  At this time, it is preferable that the kneading conditions with only the rubber component until the filler is added be at a temperature of 80 to 120 ° C. for about 0.5 to 2 minutes. If the kneading temperature is less than 80 ° C. or the kneading time is less than 0.5 minutes, the rubber component cannot be sufficiently plasticized, and the filler and other components may not be well dispersed. If the kneading temperature exceeds 120 ° C. or the kneading time exceeds 2 minutes, the rubber component may be decomposed or deteriorated.

The conditions for the subsequent kneading are not particularly limited, but the kneading after adding the filler is preferably performed at a temperature of 80 to 120 ° C. for about 0.5 to 2 minutes. The kneading after adding zinc oxide and other components is preferably performed at a temperature of 120 to 140 ° C. for about 5 to 60 seconds in order to disperse the components as uniformly as possible.
Next, the kneaded product is taken out from the kneading machine, added with a predetermined amount of sulfur, and kneaded at, for example, 80 to 90 ° C. for about 5 to 6 minutes using, for example, an open roll, a Banbury mixer, a kneader, or the like. Prepare the product. If the kneading temperature is less than 80 ° C. or the kneading time is less than 5 minutes, the kneaded product cannot be sufficiently plasticized, and sulfur may not be well dispersed. In addition, when the kneading temperature exceeds 90 ° C. or the kneading time exceeds 6 minutes, the stabilized sulfur is usually decomposed and activated by linking the eight atoms in a cyclic manner. There is a risk that the vulcanization reaction proceeds during kneading due to sulfur and so-called burning occurs.

  Next, the elastomer composition is taken out from the kneader, and set in a mold and subjected to press crosslinking, for example, to crosslink the rubber while forming the elastomer composition into a sheet, thereby cleaning the image forming apparatus. The sheet-shaped precursor is prepared, and the precursor is cut or punched out into a predetermined planar shape, whereby the image forming apparatus cleaning blade is manufactured.

  The crosslinking conditions are preferably 140 to 170 ° C. and about 20 to 40 minutes. If the crosslinking temperature is less than 140 ° C. or the crosslinking time is less than 20 minutes, the rubber component cannot be sufficiently crosslinked, and a cleaning blade for an image forming apparatus having excellent wear resistance may not be produced. is there. Further, when the crosslinking temperature exceeds 170 ° C. or the crosslinking time exceeds 40 minutes, the rubber component is decomposed or deteriorated, and a cleaning blade for an image forming apparatus having excellent wear resistance is obtained. There is a risk that it cannot be manufactured.

  The cleaning blade for an image forming apparatus of the present invention can be formed in an arbitrary size and shape according to the structure of the image forming apparatus to be incorporated, the size of the photosensitive member to be combined, and the like. For example, a cleaning blade for an image forming apparatus incorporated in a general A4 size laser printer has a thickness of 1 to 3 mm, a width of 220 to 300 mm in a direction perpendicular to the rotation direction of the photosensitive member, and a length of about 10 to 40 mm in the rotation direction. And it is sufficient.

The cleaning blade for an image forming apparatus of the present invention is excellent in wear resistance, and particularly considering that it has excellent cleaning performance for small-diameter toner and spherical toner, in particular, Japanese Industrial Standard JIS K6251: 2004 It is preferable that the tensile stress at the time of cutting specified in “Sulfur rubber and thermoplastic rubber—How to obtain tensile properties” is 10 MPa or more.
FIG. 1 is a schematic cross-sectional view of a color laser printer as an example of an image forming apparatus in which a cleaning blade for an image forming apparatus of the present invention can be incorporated. FIG. 2 is an enlarged cross-sectional view of the image forming apparatus cleaning blade portion of the image forming apparatus of the above example.

Referring to both the drawings, the color laser printer 1 of this example includes a rotating photoreceptor 2 that rotates in a direction indicated by a solid arrow in the drawings.
Further, around the photoreceptor 2, a charging roller 3 for uniformly charging the surface of the photoreceptor 2 in order along the rotation direction, the surface of the charged photoreceptor 2 is exposed, and the surface is exposed. Further, an exposure unit 4 for forming an electrostatic latent image corresponding to the formed image, and a developing unit 5 for developing the electrostatic latent image into a toner image by selectively attaching toner. .

  In the case of forming a color image, the exposure unit 4 forms a photoconductor for each image data obtained by color-separating the color image into four colors of cyan (C), magenta (M), yellow (Y), and black (K). The surface of 2 is exposed, and electrostatic latent images corresponding to the respective colors are sequentially formed on the surface of the photoreceptor. When a monochrome image such as a document is formed, the exposure unit 4 exposes the surface of the photoreceptor 2 with image data that is not subjected to color separation.

The developing unit 5 converts the electrostatic latent image into cyan (C), magenta (M), yellow (corresponding to the electrostatic latent image formed on the surface of the photoreceptor 2 by the exposure unit 4. Four developing units 6 to 9 for developing with any one color toner corresponding to the electrostatic latent image among the four color toners of Y) and black (K) are provided.
The developing units 6 to 9 are held by a rotary holding body 10 arranged in parallel with the photosensitive member 2, and the developing unit 5 rotates the holding body 10 to be one of the developing units 6 to 9. Is held in a state facing the surface of the photoreceptor 2, and the electrostatic latent image formed on the surface is developed into a toner image of a predetermined color by any of the facing developing units 6 to 9.

  An endless intermediate transfer belt 11 that is fed in the direction indicated by the solid line arrow in the drawing in synchronization with the rotation of the photosensitive member 2 and downstream of the developing means 5 around the photosensitive member 2 in the rotational direction. A transfer means 13 including a primary transfer roller 12 disposed with the intermediate transfer belt 11 sandwiched between the photosensitive member 2 and the photosensitive member 2 is disposed. The toner image formed on the surface of the photoreceptor 2 is applied from the surface of the photoreceptor 2 to the surface of the intermediate transfer belt 11 by applying a predetermined transfer voltage between the photoreceptor 2 and the primary transfer roller 12. Transcribed.

  When a color image is formed, an electrostatic latent image corresponding to the image data of the first color is first formed on the surface of the photoreceptor 2 by exposure by the exposure unit 4, and the electrostatic latent image corresponds to the development unit 5. The toner image of the first color is developed and transferred to the surface of the intermediate transfer belt 11 by the transfer unit 13. When this operation is repeated for the image data of the second color to the fourth color, and the toners of four colors are transferred onto the surface of the intermediate transfer belt 11 in order, a predetermined color image is formed on the surface of the intermediate transfer belt 11. Is formed.

When a monochrome image is formed, an electrostatic latent image corresponding to predetermined image data is formed on the surface of the photosensitive member 2 by exposure by the exposure unit 4, and the electrostatic latent image is formed in the developing unit 5 by a predetermined unit. A toner image of one color (usually black) is developed and transferred to the surface of the intermediate transfer belt 11 by the transfer means 13.
The transfer unit 13 includes a pair of secondary transfer rollers 14 and 15, and the intermediate transfer belt 11 is inserted between the secondary transfer rollers 14 and 15.

The toner image (color image or monochrome image) formed on the surface of the intermediate transfer belt 11 is passed through the secondary transfer rollers 14 and 15 while the intermediate transfer belt 11 and the paper 16 are overlapped with each other. By applying a predetermined transfer voltage between the next transfer rollers 14 and 15, the image is transferred from the surface of the intermediate transfer belt 11 to the surface of the paper 16.
The paper 16 to which the toner image has been transferred is inserted between a pair of fixing rollers 17 and 18 that are heated to a predetermined temperature, for example, as indicated by solid arrows in the drawing. As a result, the toner image is fixed on the surface of the paper 16.

When forming a color image by superimposing the toner images of the respective colors, the secondary transfer rollers 14 and 15 are separated from each other, or are applied with a transfer voltage and a reverse voltage. As a result, it is possible to prevent image defects such as a toner image being partially transferred onto the surface of the secondary transfer roller 14.
The toner remaining on the surface of the photosensitive member 2 after the toner image is transferred by the transfer unit 13 is removed from the periphery of the photosensitive member 2 in the rotation direction downstream of the transfer unit 13 and upstream of the charging roller 3. Cleaning means 19 is provided for this purpose.

The cleaning unit 19 includes a toner recovery box 20 for storing toner removed from the surface of the photoreceptor 2, and the image forming apparatus of the present invention held in the toner recovery box 20 via a support member 21. Cleaning blade 22.
As described above, the image forming apparatus cleaning blade 22 is formed in, for example, a rectangular flat plate shape, and the edge portion 23 of one side of the rectangle is in contact with the surface of the photoreceptor 2 with a predetermined linear pressure. A sliding contact is made on the surface. At that time, the toner adhering to the surface of the photosensitive member 2 can be recovered by the toner recovery box 20 and removed by being scraped off or blown off by the edge portion 23.

  Moreover, the cleaning blade 22 for the image forming apparatus of the present invention is made of the elastomer composition having the predetermined composition described above and has a large specific gravity. Therefore, the cleaning blade 22 for the image forming apparatus has a high linear pressure particularly suitable for cleaning small-diameter toner and spherical toner. Therefore, when the edge portion is in sliding contact with the surface of the photoconductor, the vibration of the edge portion is suppressed, the toner slipping by the vibration is suppressed, and the linear pressure is reduced. Good cleaning performance commensurate with the amount of increase can be exhibited. Also, because of its excellent wear resistance, when the edge portion is in contact with the surface of the photoconductor with the high linear pressure, the good cleaning performance is maintained for a longer period of time when the surface is slid on the surface. can do.

  As the support member 21, for example, a member formed of metal, hard plastic, ceramic, or the like can be used. As an adhesive for adhering the image forming apparatus cleaning blade 22 of the present invention to the support member 21, for example, a polyamide-based or polyurethane-based hot melt adhesive, an epoxy-based, phenol-based adhesive, or the like is used. In particular, a hot melt adhesive is preferable in consideration of shortening the time required for the bonding operation.

Production of the cleaning blade for an image forming apparatus of the following examples and comparative examples, measurement of characteristics, and tests were performed in an environment of a temperature of 23 ± 1 ° C. and a relative humidity of 55 ± 1%, unless otherwise specified.
<Example 1>
100 parts by mass of HXNBR as a rubber component (THERANAN (Zurban, registered trademark) XTVPKA8889 manufactured by LANXESS, Germany) was kneaded at 80 to 120 ° C. for 0.5 to 2 minutes using a Banbury mixer, and then carbon black [Tokai 20 parts by mass of a trade name Seast ISAF manufactured by Carbon Co., Ltd. was added and kneaded at 80 to 120 ° C. for 0.5 to 2 minutes.

Next, after cleaning, that is, the work of dropping the carbon black blown up when the ram of the Banbury mixer was closed for the kneading, the kneaded material was further kneaded at 120 to 140 ° C. for 1 to 5 minutes, The following components were added and kneaded at 80 to 120 ° C. for 5 to 60 seconds.
Zinc oxide [Zinc oxide two types manufactured by Mitsui Kinzoku Co., Ltd.]: 20 parts by mass Stearic acid [trade name Tsubaki manufactured by NOF Corporation]: 1 part by mass Anti-aging agent A [Ouchi Shinsei Chemical Co., Ltd. NOCRACK (registered trademark) CD, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine (CD)]: 1 part by mass anti-aging agent B [NOCRACK MB manufactured by Ouchi Shinsei Chemical Co., Ltd., 2-Mercaptobenzimidazole (MBI)]: 2 parts by mass Vulcanization accelerator A [Noxeller (registered trademark) TS, tetramethylthiuram monosulfide (TS) manufactured by Ouchi Shinsei Chemical Co., Ltd.]: 1.5 parts by mass Part Vulcanization accelerator B [Noxeller DM, dibenzothiazyl disulfide (DM) manufactured by Ouchi Shinsei Chemical Co., Ltd.]: 0.5 part by mass Next, the kneaded product was taken out from the twin-screw extruder, and in the kneaded product 100 parts by weight of rubber Add 1.5 parts by mass of sulfur (powder sulfur manufactured by Tsurumi Chemical Co., Ltd.) and knead it at 80-90 ° C for 5-6 minutes using an open roll, then set in the mold and 160 ° C. The sheet is press vulcanized for 30 minutes to produce a sheet having a thickness of 2 mm, and the sheet is punched into a rectangular flat plate having a width of 320 mm in the direction perpendicular to the rotation direction of the photoreceptor and a length of 20 mm in the rotation direction. A cleaning blade for the forming apparatus was produced.

The amount of zinc oxide was 20 parts by mass per 100 parts by mass of the total amount of rubber and 20% by mass of the amount of HXNBR.
<Example 2>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that the amount of zinc oxide per 100 parts by mass of rubber was 30 parts by mass and 30% by mass of the amount of HXNBR.

<Example 3>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that the amount of zinc oxide per 100 parts by mass of the rubber content was 45 parts by mass and 45% by mass of the amount of HXNBR.
<Example 4>
For an image forming apparatus as in Example 1 except that 30 parts by mass of HNBR (ZETPOL (registered trademark) 1020 manufactured by Nippon Zeon Co., Ltd.) and 70 parts by mass of HXNBR were used as rubber components. A cleaning blade was manufactured. The amount of zinc oxide was 20 parts by mass per 100 parts by mass of the total amount of rubber, and 28.6% by mass of the amount of HXNBR.

<Example 5>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 4 except that the amount of zinc oxide per 100 parts by mass of rubber was 31.5 parts by mass and 45% by mass of the amount of HXNBR.
<Example 6>
As a rubber component, 100 parts by mass of XNBR (KRYNAC (Clinac, registered trademark) X750 manufactured by LANXESS, Germany) is used, and the amount of zinc oxide per 100 parts by mass of the total rubber component is 30 parts by mass, which is 30 of the amount of XNBR. A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that the mass% was used.

<Comparative example 1>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that the amount of zinc oxide per 100 parts by mass of rubber was 5 parts by mass and 5% by mass of the amount of HXNBR. This corresponds to Example 22 of Patent Document 1.
<Comparative example 2>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that the amount of zinc oxide per 100 parts by mass of the rubber content was 55 parts by mass and 55% by mass of the amount of HXNBR.

<Comparative Example 3>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 6 except that the amount of zinc oxide per 100 parts by mass of the rubber content was 5 parts by mass and 5% by mass of the amount of HXNBR.
<Comparative example 4>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 6 except that the amount of zinc oxide per 100 parts by mass of rubber was 55 parts by mass and 55% by mass of the amount of HXNBR.

<Comparative Example 5>
A cleaning blade for an image forming apparatus was produced in the same manner as in Example 1 except that 40 parts by mass of HNBR and 60 parts by mass of HXNBR were used as rubber components. The amount of zinc oxide was 20 parts by mass per 100 parts by mass of the total amount of rubber and 33.3% by mass of the amount of HXNBR.

<Tensile test>
A dumbbell-shaped No. 3 test piece defined in the Japanese Industrial Standard JIS K6251: 2004 "Vulcanized rubber and thermoplastic rubber-Determination of tensile properties" And the tensile stress (MPa) at the time of cutting was measured according to the measurement method described in the standard using the test piece.

<Specific gravity measurement>
The specific gravity of the sheet having a thickness of 2 mm produced in the examples and comparative examples was measured according to the measurement method defined in Japanese Industrial Standard JIS K6268: 1998 “vulcanized rubber-density measurement”.
<Abrasion test>
The image forming apparatus cleaning blade 22 manufactured in the embodiment and the comparative example is bonded to a support member 21 as shown in FIG. 2, and a commercially available laser provided with the rotary photoreceptor 2 through the support member 21. Built into the printer. The linear pressure of the edge portion 23 of the image forming apparatus cleaning blade 22 against the surface of the photoreceptor 2 was 1.2 N / cm.

Then, after the photoreceptor 2 is rotated at a peripheral speed of 200 to 500 mm / s, an image having a printing density of 4% is continuously formed on the surface of plain paper on the surface of 150,000 sheets, and as shown in FIG. In a state where the cleaning blade 22 is held at an inclination angle of 45 ° with respect to the measurement reference surface 24, the wear surface 25 generated on the edge portion 23 is projected onto the measurement reference surface 24, and the wear surface 25 is used for an image forming apparatus. the projection dimension W ₁ in a direction orthogonal to the width direction of the cleaning blade 22 was measured to evaluate the wear resistance based on the following criteria.

◎: _{W 1} is a 0μm above is a state where there is no wear surface 25 was 5μm or less. Very good wear resistance.
○: _{W 1} is greater than 5μm, it was 10μm or less. Good wear resistance.
△: _{W 1} is greater than 10μm, it was 50μm or less. Slightly poor wear resistance.
×: _{W 1} was greater than 50μm. Insufficient wear resistance.

<Cleaning performance test>
As shown in FIG. 2, the image forming apparatus cleaning blade 22 manufactured in the embodiment and the comparative example is bonded to a support member 21, and the rotary photosensitive member 2 is provided via the support member 21, and spherical toner is used. The image forming apparatus used was incorporated in a testing machine (manufactured in-house). The linear pressure of the edge portion 23 of the image forming apparatus cleaning blade 22 against the surface of the photoreceptor 2 was 1.2 N / cm.

As the spherical toner, a toner manufactured by a polymerization method and having a volume average diameter of 5 to 10 μm and a sphericity represented by a ratio of a major axis to a minor axis of 0.90 to 0.99 was used.
Then, after rotating the photoconductor at a peripheral speed of 200 to 500 mm / s and continuously forming 150,000 sheets of images with a printing density of 4% on the surface of plain paper, the image forming apparatus cleaning blade 22 of the photoconductor. The adhesion amount Ta (μg) per unit area of the toner adhering to the surface after passing through was determined.

Then, after the photosensitive member is rotated once more without image formation, the image forming device cleaning blade 22 passes through the surface of the photosensitive member after passing through the image forming device cleaning blade 22. The adhesion amount Tb (μg) per unit area of the remaining toner was determined.
Then, Tb / Ta was obtained and the cleaning performance was evaluated. That is, it can be evaluated that the smaller the Tb / Ta is, the better the cleaning performance of the image forming apparatus cleaning blade 22 is.

<Vibration analysis>
The image forming apparatus cleaning blades produced in the examples and comparative examples were incorporated in the same manner as described above into the same image forming apparatus testing machine (made in-house) used in the cleaning performance test.
Then, while rotating the photosensitive member, the tip of one side including the edge portion of the cleaning blade for the image forming apparatus was photographed using a high-speed video camera (FASTCAM APX RS manufactured by Photoron Co., Ltd.) The tracking software [Dipp Motion Pro2D manufactured by Detect Co., Ltd.] was used as data, and this data was subjected to wavelet analysis (vibration analysis) to confirm the vertical movement of the tip, that is, stick-slip behavior.

That is, in the wavelet analysis, the vibration element is decomposed into three dimensions (time X, frequency Y, power Z), and the magnitude of vibration (power Z) is obtained as wavelet data expressed in color. The obtained wavelet data was visually confirmed and evaluated as “large” when the amount of red was large, “medium” when there was a lot of yellow, and “small” when there was a lot of green.
The above results are shown in Tables 1 and 2.

  From the results of Examples and Comparative Examples in both tables, XNBR and / or HXNBR as a rubber component is contained in a range of 70% by mass or more, and the amount of zinc oxide per 100 parts by mass of the rubber component is 20 parts by mass or more. In addition, the specific gravity is increased by forming a cleaning blade for an image forming apparatus using an elastomer composition having an amount of 45% by mass or less of the amount of XNBR and / or HXNBR, and particularly suitable for cleaning a small particle size toner or a spherical toner. When the edge portion is brought into contact with the surface of the photosensitive member with a high linear pressure, the edge portion is suppressed from vibration, and toner slippage due to the vibration is suppressed. It is possible to exhibit good cleaning performance commensurate with the increase in the linear pressure, improve the wear resistance, and expose the edge portion of the photoconductor with the high linear pressure. When obtained by sliding over the surface held in contact, the more over a long period of time, it has been found capable of maintaining the good cleaning performance.

DESCRIPTION OF SYMBOLS 1 Color laser printer 2 Photoconductor 3 Charging roller 4 Exposure means 5 Developing means 6, 7, 8, 9 Developing part 10 Holding body 11 Intermediate transfer belt 12 Primary transfer roller 13 Transfer means 14, 15 Secondary transfer roller 16 Paper 17, 18 Fixing roller 19 Cleaning means 20 Toner recovery box 21 Support member 22 Cleaning blade 23 for image forming apparatus Edge portion 24 Measurement reference surface 25 Wear surface

Claims (3)

A cleaning blade for an image forming apparatus comprising an elastomer composition, wherein the elastomer composition is a rubber component,
(1-1) at least one rubber selected from the group consisting of carboxylated acrylonitrile butadiene rubber and hydrogenated carboxylated acrylonitrile butadiene rubber; or
(1-2) A mixed rubber comprising the rubber (1-1) and a hydrogenated acrylonitrile butadiene rubber, wherein the amount of the rubber (1-1) in the total amount of both is 70% by mass or more ,
Any one of and
(2) a crosslinking agent, and
(3) Zinc oxide that is 20 parts by mass or more per 100 parts by mass of the total rubber content and 45% by mass or less of the amount of the rubber of (1-1),
A cleaning blade for an image forming apparatus.   2. The cleaning blade for an image forming apparatus according to claim 1, wherein the hydrogenated acrylonitrile butadiene rubber is a hydrogenated acrylonitrile butadiene rubber having a residual double bond amount of 3% or more and 10% or less.   The image forming apparatus cleaning blade according to claim 1, wherein the crosslinking agent is sulfur, and the sulfur is contained in a range of less than 2.5 parts by mass per 100 parts by mass of the total amount of the rubber.

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