JP2007004044A - Reproduction elastic roll, reproducing method of elastic roll, developer carrying roll, electrophotographic process cartridge, and electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reproducing method of an elastic roll which is simple and does not damage roll performance, a reproduction shaft core body used for it, a reproduction elastic roll which is excellent in performance and low in cost, a developer carrying roll, an electrophotographic process cartridge, and an electrophotographic image forming apparatus. <P>SOLUTION: The reproduction elastic roll has: a shaft core body; a first elastic layer (thickness ta) formed around the shaft core body before reproduction; and a second elastic layer formed around the first elastic layer in reproduction, and satisfies ta≤0.2tb (tb:the total thickness of the first and second elastic layers) and ta≥0.2mm. The reproducing method of an elastic roll is for obtaining the reproduction elastic roll. The developer carrying roll using the reproduction elastic roll, the electrophotographic process cartridge having the developer carrying roll, and the image forming apparatus are provided. The reproduction shaft core body is obtained from the elastic roll having an elastic layer on the shaft core body and has only the part having the thickness ta of the elastic layer, on the outer periphery of the shaft core body and satisfies ta≤0.2tc (tc:the total thickness of the elastic layer of the elastic roll) and ta≥0.2mm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for regenerating an elastic roll, a regenerated elastic roll, and a regenerative shaft core used for the method. The present invention also relates to an electrophotographic image forming apparatus such as a copying machine or a laser beam printer, an electrophotographic process cartridge used in the electrophotographic image forming apparatus, and a developer carrying roll.

  Conventionally, as a method for producing an elastic roll using a metal shaft core, a method in which a rubber elastic layer is formed in advance by extrusion or the like, and the obtained elastic tube is press-fitted into the shaft core, or is necessary. An injection molding method is used in which a shaft core is placed in a mold having a roll-shaped internal structure, a material is injected into the mold, and then cured. In these roll manufacturing methods, various defective phenomena such as defects in the outer diameter shape, dents on the roll surface, and adhesion of foreign matters may occur, and in addition, when an outer layer is provided on the surface of this elastic layer by coating or the like Also, coating defects such as uneven surface properties may occur in this coating layer. The elastic roll in which such a defect has occurred becomes a defective product and cannot be shipped and is discarded.

  However, from the viewpoint of cost reduction as well as from the viewpoint of environmental conservation, reducing the amount of defective products discarded has become a very important issue. That is, there is an increasing demand for extracting and reusing a part of the material constituting the roll from defective products that have been processed once but cannot be used and discarded.

  In response to such demands, a method is widely used in which an elastic body portion is peeled off from a processed elastic roll and only the shaft core body is reused. Thereby, not only can the raw material cost for the roll be reduced during reuse, but also metal resources used for the metal shaft core can be effectively utilized.

  However, the shaft core used for the elastic roll is usually provided with a layer having an adhesive property at the boundary surface with the elastic body, and the metal shaft core and the elastic body are bonded to each other. By simply pulling out the shaft core from the roll, the shaft core in the original state cannot be obtained. That is, since an elastic body remains attached to the surface, the remaining elastic body has to be removed by polishing or wiping. At this time, the shaft core surface may be scratched, and in order to reuse the scratched shaft core body, additional processing such as re-plating is required as shown in Patent Document 1. It was.

  From the viewpoint of reducing the amount of elastic body material required when reusing the shaft core without requiring additional processing, only the defective part of the elastic roll surface when regenerating the shaft core A method of removing and re-using as an elastic roll is also proposed in Patent Document 2.

However, when the shaft core regenerated by the above method is used, the elastic layer adhering to the regenerated shaft core is subjected again to heat treatment necessary for hardening of the elastic layer at the time of reworking. There was a concern that the required performance required for the elastic layer could not be satisfied.
JP 2000-291737 A JP 09-155427 A

  An object of the present invention is to provide a method for regenerating an elastic roll that is simple without requiring additional treatment such as plating and that does not impair the performance of the elastic roll, has good performance, and is relatively low. An object of the present invention is to provide a cost-effective regenerative elastic roll and to provide a regenerative shaft core suitable for use in this.

  Another object of the present invention is to provide a developer-carrying roll, an electrophotographic process cartridge, and an electrophotographic image forming apparatus having good performance and relatively low cost by using such a regenerated elastic roll. .

According to the present invention, the shaft core includes: a first elastic layer formed around the shaft core before reproduction; and a second elastic layer formed around the first elastic layer during reproduction. When the thickness of the first elastic layer is ta and the total thickness of the first and second elastic layers is tb,
There is provided a regenerated elastic roll in which ta ≦ 0.2 tb and ta is 0.2 mm or more.

  It is preferable that the first and second elastic layers are both cured products of addition reaction crosslinking liquid silicone rubber.

  According to the present invention, there is provided a developer carrying roll comprising the regenerated elastic roll in which at least the surface of the shaft core is made of metal and the first and second elastic layers have conductivity.

According to the present invention, a developer-carrying roll is provided, a thin layer of developer is formed on the surface of the developer-carrying roll, and the developer-carrying roll is brought into contact with or in proximity to the image-forming body. In an electrophotographic process cartridge that forms a visible image on the surface of the image forming body by supplying the developer,
An electrophotographic process cartridge is provided in which the developer carrying roll is the developer carrying roll.

According to the present invention, a developer-carrying roll is provided, a thin layer of developer is formed on the surface of the developer-carrying roll, and the developer-carrying roll is brought into contact with or in proximity to the image-forming body. In an electrophotographic image forming apparatus that forms a visible image on the surface of the image forming body by supplying the developer,
An electrophotographic image forming apparatus is provided in which the developer carrying roll is the developer carrying roll according to claim 3.

According to the present invention, there is provided a method for regenerating an elastic roll having a shaft core and an elastic layer disposed around the shaft core,
A peeling step of peeling the elastic layer from the outer peripheral side leaving the thickness ta; and
An elastic layer is newly formed around the elastic layer left in the peeling step, and the elastic layer has a total thickness tb.
Provided is a method for regenerating an elastic roll in which ta ≦ 0.2 tb and ta is 0.2 mm or more.

According to the present invention, a regenerative shaft core obtained from an elastic roll having a shaft core and an elastic layer disposed around the shaft core,
When the total thickness of the elastic layer of the elastic roll is tc,
Around the shaft core, it has only a portion of the elastic layer with a thickness ta,
A reproducing shaft core body is provided in which ta ≦ 0.2tc and ta is 0.2 mm or more.

  According to the present invention, there is provided a method for regenerating an elastic roll that is simple without requiring additional processing such as plating and that does not impair the performance of the elastic roll, has good performance, and is relatively low cost. A regenerative elastic roll is provided, and a regenerative shaft core that can be suitably used for this is provided.

  According to the present invention, a developer carrying roll, an electrophotographic process cartridge, and an electrophotographic image forming apparatus having good performance and relatively low cost are provided using such a regenerated elastic roll.

  The present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view perpendicular to the axis of one embodiment of the regenerated elastic roll of the present invention. A cylindrical first elastic layer is present on the outer peripheral surface of the round rod-shaped shaft core body 11 via an adhesive layer (not shown), which is present in the elastic roll before the reproduction and is left without being peeled off during the reproduction. There are twelve. The thickness of the first elastic layer is represented by ta. On the outer peripheral surface of the first elastic layer, there is a cylindrical second elastic layer (first layer) 13 newly formed during reproduction. Further, a surface layer 14 formed as necessary exists around the second elastic layer as a second layer of the second elastic layer. The total thickness of the first and second elastic layers is represented by tb.

  Any of the elastic layer, the first elastic layer, and the second elastic layer of the original elastic roll to be reproduced may have a single layer structure or a multilayer structure.

  When the elastic layer of the original elastic roll is peeled off, the thickness of the first elastic layer is set to 0.2 mm or more from the viewpoint of protecting the shaft core surface during peeling.

  Further, in order to avoid that the physical properties such as the setting property of the regenerative elastic roll are lower than the elastic roll in the case of newly manufacturing, the thickness ta of the first elastic layer is the total elastic layer of the regenerative elastic roll. The thickness (that is, the sum of the thickness of the first elastic layer and the thickness of the second elastic layer) tb is 0.2 times or less.

  The regenerative shaft core body for the elastic roll refers to a shaft core body regenerated from the elastic roll, but does not necessarily mean only the shaft core body, and may include members other than the shaft core body. The reproducing shaft core of the present invention has a part of the elastic layer on the shaft core. Specifically, the reproduction shaft core body 15 of the present invention can be obtained by a peeling process, and has a first elastic layer 12 around the shaft core body 11.

  As a material for forming the second elastic layer (the layer closest to the first elastic layer when the second elastic layer has a multilayer structure), the first elastic layer (the first elastic layer has a multilayer structure) In the case of having the same, the same material as the material of the layer closest to the second elastic layer) is preferable from the viewpoint of compatibility, but it is not necessarily limited thereto. In the case where the adhesiveness between the first elastic layer and the second elastic layer is in a desired range and does not cause curing inhibition, the same material may not be used.

  Moreover, when reproducing | regenerating an elastic roll, the reproduction | regeneration elastic roll of the same specification as the original elastic roll is usually produced. In such a case, the total thickness tc of the elastic layer of the original elastic roll is the same as the total thickness tb of the elastic layer of the regenerative elastic roll. When tc and tb are the same, in order to create a regenerative elastic roll, it has only a portion of the thickness ta of the original elastic layer (thickness tc) around the shaft core body, ta ≦ 0.2tc, And the reproduction | regeneration axial center body whose ta is 0.2 mm or more can be used conveniently.

[Shaft core regeneration method]
FIG. 2 is a schematic view for explaining an example of a method for peeling a part of the elastic layer of the elastic roll.

  As a method of peeling a part of the elastic layer from the outer peripheral side of the elastic roll, that is, a method of taking out the reproduction shaft core body, a method of peeling the elastic layer around the shaft core body by leaving a desired thickness by polishing. Alternatively, a method of peeling by blasting or a method of scraping manually can be employed. However, the following method is preferable as a method that can leave a relatively uniform film thickness in a shorter time and with fewer man-hours than these methods.

  That is, as shown in FIG. 2, a plate-like member (called an elastic layer peeling plate) in which a hole (called an elastic layer peeling hole) 24 having a diameter corresponding to the thickness of the elastic layer that is desired to be left is opened from the diameter of the roll core. ) 21 and passing an elastic roll through the elastic layer peeling hole, a regenerated shaft core body in which an elastic layer having a desired thickness is left on the shaft core body can be obtained. A blade is attached to the entrance side of the hole 24 through which the shaft core body passes in order to cut the elastic body and make it easy to peel off.

  It is also possible to use a plurality of peeling methods in combination.

(Shaft core)
The material of the shaft core body can be appropriately selected from known materials as the shaft core body of the elastic roll in consideration of rigidity and the like. The shape is usually round or cylindrical.

  In the case of conductive elastic rolls used in electrophotographic processes such as developer-carrying rolls, the shaft core is in the form of a round bar or cylinder whose surface is a metal, and is iron, aluminum, titanium, copper and nickel. Desired rigidity such as a round bar or cylinder made of an alloy such as stainless steel, duralumin, brass and bronze, or a non-conductive plastic round bar or cylinder formed with a metal conductive layer A known material can be used as the shaft core of a conductive elastic roll having a thickness and at least a surface of a metal. For example, in the case of carbon steel, iron, etc., it is also preferable that the surface is chemically plated with nickel at a thickness of 2 to 20 μm, preferably 3 to 10 μm.

  The diameter of the shaft core is appropriately determined depending on the purpose of the shaft core material and the elastic roll. For example, in an elastic roll used in an electrophotographic process, the diameter is usually 4 to 10 mm.

[Elastic layer]
The material of the elastic layer can be appropriately selected from known elastic layers of elastic rolls. The degree of elasticity can be appropriately determined according to the purpose of use.

  In the case of a conductive elastic roll, the elastic layer has conductivity. The degree of conductivity can be appropriately determined according to the purpose of use.

  In the case of a conductive elastic roll used in an electrophotographic process, a liquid rubber material, preferably a liquid addition reaction cross-linked silicone rubber, blended with a conductive filler such as carbon black as a conductivity imparting agent as a material of the elastic layer Is preferably used.

(Liquid silicone rubber material)
As a material for the elastic layer, it is excellent in processability, has no dimensional stability due to the absence of by-products associated with the curing reaction, and has a liquid addition reaction for reasons such as stable physical properties after curing. Cross-linked silicone rubber is preferably used.

  This addition reaction-crosslinking type silicone rubber includes, for example, an organopolysiloxane represented by the formula (1) and an organohydrogenpolysiloxane represented by the formula (2), and these, and a catalyst and other additives, Can be used by appropriately mixing them.

  In addition, the composition obtained by mix | blending a catalyst and an additive with the organopolysiloxane represented by Formula (1) and the organohydrogenpolysiloxane represented by Formula (2) is called a liquid silicone rubber material.

In the formula, R ¹ and R ² are alkenyl groups which may be the same or different from each other, and x is a positive integer.

  The organopolysiloxane represented by the formula (1) is a base polymer of a liquid silicone rubber raw material, and the molecular weight thereof is not particularly limited, but is preferably 100,000 or more and 1,000,000 or less, and the weight average molecular weight is preferably 400,000 or more and 700,000 or less. . Furthermore, from the viewpoint of processing characteristics and characteristics of the resulting liquid silicone rubber composition, the viscosity (at 25 ° C.) of the organopolysiloxane is preferably 10 Pa · s or more, more preferably 50 Pa · s or more as the lower limit, The value is preferably 300 Pa · s or less, and more preferably 250 Pa · s or less.

  The alkenyl group of the organopolysiloxane represented by the formula (1) is a site that reacts with the active hydrogen of the organohydrogenpolysiloxane to form a crosslinking point, and the type thereof is not particularly limited, but the reaction with the active hydrogen For reasons such as high properties, it is preferably selected from vinyl groups and allyl groups, with vinyl groups being particularly preferred.

  In the formula, y is a positive integer of 2 or more, and z is a positive integer.

  The organohydrogenpolysiloxane represented by the formula (2) serves as a crosslinking agent for addition reaction in the curing process, and the number of silicon-bonded hydrogen atoms in one molecule is 2 or more, and the curing reaction From the viewpoint of excellent performance, it is preferable that the number of silicon-bonded hydrogen atoms in one molecule is 3 or more.

  There are no particular restrictions on the molecular weight of the polyorganohydrogenpolysiloxane, for example, those having a molecular weight of 1000 to 10,000 are contained, but a relatively low molecular weight (for example, a weight average molecular weight of 1000 or more, for example) is required in order to appropriately carry out the curing reaction. 5000 or less) is preferable.

(Crosslinking catalyst)
As a crosslinking catalyst for the reaction of organopolysiloxane and organohydrogenpolysiloxane, for example, chloroplatinic acid hexahydrate can be used, and a transition metal compound that exhibits a catalytic action in hydrosilylation reaction can also be used. is there. Specific examples thereof include Fe (CO) ₅ , Co (CO) ₈ , RuCl ₃ , IrCl ₃ , [(olefin) PtCl ₂ ] ₂ , vinyl group-containing polysiloxane-Pt complex, L ₂ Ni (olefin), L ₄ Pd, L ₄ Pt, L ₂ NiCl ₂ (wherein L is PPh ₃ or PR ′ ₃ , where P is phosphorus, Ph is a phenyl group, and R ′ is an alkyl group). Among these, platinum, palladium, and rhodium-based transition metal compound catalysts are preferable.

  In the case of a platinum-based metal compound catalyst, the compounding amount of the catalyst is preferably 1 to 100 ppm by mass as platinum in the liquid silicone rubber material, but is not limited to this range, and the target pot life and curing It is appropriately selected depending on time, product shape and the like.

(Curing reaction retarder)
Further, the liquid silicone rubber material can contain an unsaturated alcohol such as 1-ethynyl-1-cyclohexanol or phenylbutynol as a curing reaction retarder. The amount of the curing reaction retarder is appropriately selected depending on the target pot life, curing time, and product shape in the range of 0.05 to 0.5 parts by mass with respect to 100 parts by mass of the organopolysiloxane. .

(filler)
Examples of fillers (reinforcing fillers and extenders) that can be included in the liquid silicone rubber material include fumed silica, wet silica, quartz fine powder, diatomaceous earth, carbon black, zinc oxide, basic magnesium carbonate, activated carbon. Calcium acid, magnesium silicate, aluminum silicate, titanium dioxide, talc, mica powder, aluminum sulfate, calcium sulfate, barium sulfate, glass fiber, carbon black for rubber, organic reinforcing agent, organic filler can be mentioned. It is preferable that the surface of these fillers is treated with an organosilicon compound such as polydiorganosiloxane to make it hydrophobic so as to increase dispersibility in the liquid silicone rubber material.

(Conductive agent)
Examples of the conductive agent that can be included in the elastic layer, particularly the conductive agent that can be included in the liquid silicone rubber include metal powders and fibers such as aluminum, palladium, iron, copper, and silver; titanium oxide , Metal oxide powders such as tin oxide and zinc oxide; metal compound powders such as copper sulfide and zinc sulfide; tin oxide, antimony oxide, indium oxide, molybdenum oxide, zinc, aluminum, gold, silver, Powder with copper, chromium, cobalt, iron, lead, platinum or rhodium deposited by electrolytic treatment, spray coating or mixed shaking; and acetylene black, ketjen black, PAN carbon black, pitch carbon black, etc. Carbon powder. Further, ion conductive materials such as KSCN, LiClO ₄ , NaClO ₄ , and quaternary ammonium salts can be used.

  As the conductive agent, carbon black is particularly preferable because the electrical resistivity can be reduced by adding a relatively small amount and conductivity can be imparted without increasing the hardness of the rubber composition.

(Physical properties of liquid silicone rubber materials)
The viscosity ρ (measured at 25 ° C.) of the liquid silicone rubber material in which necessary fillers are blended is not particularly limited, but is 10 Pa · s or more from the viewpoint of suppressing material flow to some extent and preventing material leakage. Preferably, 300 Pa · s or less is preferable from the viewpoint of avoiding the problem of moldability such as the occurrence of welds between the injection gates.

(Formation of elastic layer)
An example of a method for forming a conductive elastic layer when an addition reaction cross-linkable liquid silicone rubber is used as the rubber material will be described.

  A metal shaft core (core metal) coated with a vulcanized adhesion type silicone rubber primer is placed in a cylindrical mold and inside the elastic layer forming cavity formed between the mold and the core metal. The above-mentioned liquid silicone rubber material is injected into the mold, and is subjected to primary heat vulcanization in a mold at 100 to 150 ° C. for 0.1 to 1 hour, and then the molded product is taken out, and if necessary, in a constant temperature bath at 180 to 220 ° C. The heat vulcanization can be completed with a conductive elastic layer on the metal core.

  In order to form the second elastic layer around the first elastic layer, a method similar to the above can be employed. In this case, the second elastic layer can be formed without applying a primer to the surface of the first elastic layer. Alternatively, a primer may be used in order to improve the adhesion between the first elastic layer and the second elastic layer.

  The thickness of the conductive elastic layer used in the electrophotographic process is usually 2 to 6 mm, preferably 3 to 5 mm.

(Formation of surface layer)
A resin layer can be further formed as a surface layer on the elastic layer prepared as described above. In the present invention, the surface layer is also a part of the elastic layer.

  As a material for forming the resin layer, for example, various polyamides, fluorine resins, hydrogenated styrene-butylene resins, urethane resins, silicone resins, polyester resins, phenol resins, imide resins, olefin resins, and the like can be used.

  These materials can be dispersed in methyl ethyl ketone, toluene, methyl isobutyl ketone, or the like as a suitable solvent using a conventionally known dispersing apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill. By performing this dispersion, a coating solution for obtaining a surface layer with few surface defects can be obtained.

  The obtained dispersion for forming the surface layer can be applied on the elastic layer by spray coating, dipping, or the like.

  The thickness of the surface layer is preferably 5 μm or more from the viewpoint of excellently preventing the elastic layer component under the surface layer from seeping out and contaminating the image forming body in the case of an elastic roll used in an electrophotographic process. From the viewpoint of preventing the surface of the roll from becoming hard and preventing toner fusion, the thickness is preferably 500 μm or less, more preferably 10 to 30 μm.

  When the elastic roll is a developer-carrying roll, it is possible to facilitate transport of the developer on the surface of the developer-carrying roll by dispersing fine particles having a mass average particle diameter of 1 to 20 μm in the surface layer. This is preferred because an amount of developer can be transported to the development area. Examples of the fine particles used for such purpose include plastic pigments such as polymethyl methyl methacrylate fine particles, silicone rubber fine particles, polyurethane fine particles, polystyrene fine particles, amino resin fine particles, and phenol resin fine particles. In particular, polymethyl methyl methacrylate fine particles and polyurethane fine particles are preferred. These fine particles are preferably added in an amount of about 3 to 200% by mass with respect to the total mass of the surface layer constituent components excluding the fine particles.

[Image forming apparatus]
Next, FIG. 3 schematically shows an example of a contact developing type image forming apparatus using an electrophotographic process cartridge incorporating the developer carrying roll of the present invention.

  Photosensitive drum 31 that is an image forming body, primary charging roll 32, developer carrying roll 33, developer supply roll 34, toner layer thickness regulating member 35 that is a developer layer thickness regulating member, stirring blade 36, and developer. The toner 37 is collected in one cartridge, and is a cartridge that can be integrally replaced in the electrophotographic apparatus.

  The photosensitive drum 31 uniformly charged by the primary charging roll 32 rotates in the direction of the arrow, and a laser beam 40 on which recording information is placed on the surface between the primary charging roll 32 and the developer supply roll 33 is generated. Irradiation forms a latent image. On the other hand, the toner 37 sent to the developer supply roll 34 by the stirring blade 36 is uniformly coated on the surface of the developer carrying roll 33 by the toner layer thickness regulating member 35, and is carried to the surface of the photosensitive drum 31. The latent image formed on the surface of the drum 31 is visualized as a toner image. When the photosensitive drum 31 further rotates and the toner image reaches the transfer region, the toner image is transferred onto a recording medium 43 such as paper by a transfer roll 42 that is opposed to the photosensitive drum 31. The surface of the photosensitive drum 31 is uniformly charged again by the primary charging roll 32 after the toner remaining without being transferred to the recording medium 43 is removed by the cleaning elastic member 38.

  The unfixed toner image transferred to the recording medium 43 passes between the fixing roll 44 and the pressure roll 45, is fixed to the recording medium by pressure and heat, and is discharged from the electrophotographic apparatus.

  On the other hand, the developer carrying roll 33 is returned to the developing container 41 while the toner remaining without being used for development is carried on the surface. Inside the developer container 41, the developer supply roll 34 removes toner remaining on the surface of the developer carrying roll 33 from the surface of the developer carrying roll 33 and supplies new toner to the surface of the developer carrying roll 33. The new toner supplied to the surface of the developer carrying roll 33 has its layer thickness uniformly adjusted by the toner layer thickness regulating member 35 and is conveyed to the development area. By repeating this, new toner is always uniformly coated on the developer carrying roll 33, and the electrostatic latent image is developed.

  According to the present invention, when the elastic layer is peeled off from the elastic roll, a part of the elastic layer is left without peeling off all the elastic layers from the shaft core body, thereby reducing the time taken to regenerate the shaft core body. Not only can it be done, it is possible to avoid scratching the shaft core. Therefore, additional processing such as plating is not necessary. Furthermore, when a new elastic layer is formed, there is already an elastic layer that is bonded to the shaft core body, so there is no need to form an adhesive layer on the shaft core body. Moreover, since the elastic material used newly occupies 80% or more of the total thickness of the elastic layer, the performance of the regenerated elastic roll can be made equivalent to that of the new elastic roll.

  Therefore, according to the present invention, the regenerative shaft core body and further the regenerative elastic roll can be manufactured with few steps. In addition, as for the characteristics of the regenerated elastic roll, compared with the case where the shaft core regenerated by the conventional method is used, the shaft core is not damaged, the roll performance is deteriorated, and there is no local physical property abnormality. It is possible.

  In addition, the amount of elastic material used when creating the regenerated elastic roll can be reduced as compared with the case of newly producing an elastic roll.

  Hereinafter, the present invention will be described in more detail with reference to examples. This does not limit the invention in any way.

(Measurement of elastic layer thickness)
The thickness of the elastic layer was calculated from the measured outer diameter of the elastic roll and the shaft core. That is, as shown in FIG. 4, the elastic roll or shaft core body 402 is placed between the laser beams (between the laser light emitting unit 402 and the laser light receiving unit 403) of a laser length measuring device (trade name: LS-5040, manufactured by Keyence Corporation). It was inserted and rotated at a rotation speed of 120 ° / s, and the outer diameter was measured at intervals of 0.33 ms (rotation angle every 3.6 °). Thereafter, the data for one roll (100 pieces) of the roll or the shaft core was averaged to obtain the outer diameter at that position. As shown in FIG. 5, the outer diameter measurement points in the longitudinal direction of the roll or the shaft core were set to L1 (injection side) and L2 (outlet side), respectively, from the end of the elastic layer at the center of 20 mm. Further, the center of L1 and L2 was LC. The average value of the outer diameters at the points L1, L2, and LC was taken as the outer diameter of the measurement object. The elastic layer thickness was defined as 1/2 of the difference in outer diameter between the measurement points of the elastic roll and the shaft core measured in this manner.

[Example 1]
An elastic roll to be regenerated was prepared. The shaft body of this elastic roll was obtained by electroless nickel plating having a thickness of 5 μm on an iron round bar having a diameter of 8 mm and a length of 280 mm. In addition, a silicone rubber layer having a length of 230 mm and a thickness of 4 mm was disposed as an elastic layer on the shaft core. Furthermore, on the outer periphery, a surface layer formed by blending polyurethane particles with urethane particles having an average particle diameter of 15 μm and conductive carbon black was disposed.

  An elastic layer peeling plate having an elastic layer peeling hole with a diameter of 9.6 mm having the structure shown in FIG. 2 is used, and this elastic roll is passed through the elastic layer peeling hole, leaving the elastic layer with a thickness of 0.8 mm. It peeled and the reproduction | regeneration axial core body was obtained.

  Next, this reproduction shaft core was set in a cylindrical mold having an inner diameter of 16 mm while holding it from both ends. Addition reaction crosslinking type liquid silicone rubber (organopolysiloxane / organohydrodiene polysiloxane / conductive carbon black / platinum catalyst / quartz / silica is appropriately blended into the mold through the injection port provided on the piece, in a liquid state. The outer peripheral surface of the elastic layer (first elastic layer) on the reproduction shaft core is injected by injecting a cured Asuka C hardness 40 degree product with a viscosity of 150 Pa · s, and heated and cured at 150 ° C. for 30 minutes. A new elastic layer (first layer of the second elastic layer) was formed thereon.

  On the surface of the obtained second elastic layer (first layer), a coating liquid in which urethane particles having an average particle diameter of 15 μm and conductive carbon black are uniformly dispersed in a polyurethane resin raw material is dip-coated and heat-treated. This was cured to form a uniform polyurethane resin layer (second layer of the second elastic layer) having a thickness of 20 μm, and a regenerated elastic roll usable as a developer carrying roll was obtained.

  The obtained regenerated shaft core body was checked for scratches, and the amount of elastic material used when creating the regenerated elastic roll was investigated by the ratio of the elastic material used amount when the new shaft core body was used. Summarized.

  Furthermore, the regenerative elastic roll is set as a developer carrying roll on an electrophotographic process cartridge, and left in an environment with an environmental temperature of 40 ° C. and a relative humidity of 90% for one week, and then this cartridge is attached to an electrophotographic image forming apparatus for image evaluation. went. At that time, it was confirmed whether or not the contact trace with the layer thickness regulating member appeared in the image, and this result was also summarized in the set image evaluation result column of Table 1.

  In the table, the reproduction shaft core appearance and the evaluation result of the set image are ○ when it is excellent, △ when it is not acceptable but within the allowable range, × when it cannot be used as a developer carrying roll In particular, when it was inferior, it was represented by xx. Further, in the comprehensive judgment, “◯” is indicated when the developer carrying roll can be used, and “X” when the developer carrying roll cannot be used.

  In Example 1, the setability was slightly inferior to that when a new shaft core was used, but it was within an allowable range, and the cored bar was not damaged. This regenerated elastic roll could be suitably used as a developer carrying roll.

[Example 2]
A developer carrying roll using the reproduction shaft core was prepared in the same manner as in Example 1 except that the diameter of the elastic layer peeling hole was changed and the elastic layer thickness remaining on the reproduction shaft core was 0.2 mm. The same items as in Example 1 were evaluated, and the results are summarized in Table 1.

  In the regenerated elastic roll of Example 2, since the thickness of the first elastic layer was relatively thin, the shaft core body was slightly scratched, but was within the allowable range, and there was no problem in setability, and the developer carrying It was suitably usable as a roll.

Example 3
A developer-carrying roll using the reproduction shaft core was prepared in the same manner as in Example 1 except that the elastic layer thickness remaining on the reproduction shaft core was 0.4 mm, and the same items as in Example 1 were evaluated. The results are summarized in Table 1.

  Although the regenerative elastic roll of Example 3 has a thickness sufficient to prevent the shaft core from being scratched even though the first elastic layer is thin, there is a problem in the scratch and setability of the shaft core. And it was suitably usable as a developer carrying roll.

[Comparative Example 1]
As in Example 1, after the elastic layer was peeled off, the elastic layer remaining on the shaft core body was completely removed from the shaft core body by polishing, and no elastic material was left on the regenerated shaft core body. In the same manner as in Example 1, a developer-carrying roll using a reproduction shaft core was prepared, and the same items as in Example 1 were evaluated. The results are summarized in Table 1.

  The regenerated elastic roll of Comparative Example 1 was not suitable for use as a developer carrying roll due to scratches on the shaft core (core metal).

[Comparative Example 2]
A developer-carrying roll using the regenerated shaft core is prepared in the same manner as in Example 1 except that the elastic layer thickness remaining on the regenerated shaft core is 3 mm, and the same items as in Example 1 are evaluated. The results are summarized in Table 1.

  The regenerated elastic roll of Comparative Example 2 had poor setability and was not suitable for use as a developer carrying roll.

[Comparative Example 3]
A developer-carrying roll using the regenerated shaft core was prepared in the same manner as in Example 1 except that the elastic layer thickness remaining on the regenerated shaft core was 0.1 mm, and the same items as in Example 1 were evaluated. The results are summarized in Table 1.

  The regenerated elastic roll of Comparative Example 3 was not suitable for use as a developer-carrying roll because it exceeded the allowable range of scratches on the shaft core for suitability for use as a developer end-supporting roll.

[Comparative Example 4]
A developer-carrying roll using the reproduction shaft core was prepared in the same manner as in Example 1 except that the thickness of the elastic layer remaining on the reproduction shaft core was 1.0 mm, and the same items as in Example 1 were evaluated. The results are summarized in Table 1.

  The regenerated elastic roll of Comparative Example 4 had insufficient setability and was not suitable for use as a developer carrying roll.

  The present invention can be suitably used, for example, when reproducing a developer carrying roll for an electrophotographic process cartridge or an electrophotographic image forming apparatus.

It is sectional drawing which shows a cross section perpendicular | vertical to the axis | shaft of an example of the reproduction | regeneration elastic roll of this invention. It is a conceptual diagram for demonstrating an example of the method of obtaining the reproduction | regeneration axial core body of this invention. 1 is a conceptual diagram of an example of an image forming apparatus of the present invention. It is a schematic diagram of the apparatus used for the measurement of elastic layer thickness. It is a schematic diagram for demonstrating the measurement of an elastic layer thickness.

Explanation of symbols

11: Shaft core 12: First elastic layer 13: Second elastic layer 14: Surface layer (included in the second elastic layer)
15: Reproduction shaft core 21: Elastic layer peeling plate 22: Elastic roll 23: Reproduction shaft core body 24: Elastic layer peeling hole 31: Photoreceptor drum 32: Primary charging roll 33: Developer carrying roll 34: Developer supply roll 35: toner layer thickness regulating member 36: stirring blade 37: toner 38: cleaning elastic member 40: laser beam 41: developing container 42: transfer roll 43: recording medium 44: fixing roll 45: pressure roll 401: roll or shaft Core 402: Laser light emitting unit 403: Laser light receiving unit

Claims (7)

A first elastic layer having a first elastic layer formed around the shaft core before reproduction; and a second elastic layer formed at the time of reproduction around the first elastic layer. When the thickness of the layer is ta and the total thickness of the first and second elastic layers is tb,
A regenerative elastic roll in which ta ≦ 0.2 tb and ta is 0.2 mm or more.   2. The regenerated elastic roll according to claim 1, wherein each of the first and second elastic layers is a cured product of an addition reaction crosslinking liquid silicone rubber.   The developer carrying roll comprising a regenerative elastic roll according to claim 1 or 2, wherein at least the surface of the shaft core body is made of metal, and the first and second elastic layers have conductivity. A developer-carrying roll, forming a thin layer of developer on the surface of the developer-carrying roll, and bringing the developer-carrying roll into contact with or in proximity to the image-forming body, In an electrophotographic process cartridge that forms a visible image on the surface of the image forming body by supplying,
The electrophotographic process cartridge, wherein the developer carrying roll is the developer carrying roll according to claim 3. A developer-carrying roll, forming a thin layer of developer on the surface of the developer-carrying roll, and bringing the developer-carrying roll into contact with or in proximity to the image-forming body, In the electrophotographic image forming apparatus for forming a visible image on the surface of the image forming body by supplying
The electrophotographic image forming apparatus, wherein the developer carrying roll is the developer carrying roll according to claim 3. A method for regenerating an elastic roll having a shaft core and an elastic layer disposed around the shaft core,
A peeling step of peeling the elastic layer from the outer peripheral side leaving the thickness ta; and
An elastic layer is newly formed around the elastic layer left in the peeling step, and the elastic layer has a total thickness tb.
A method for regenerating an elastic roll in which ta ≦ 0.2 tb and ta is 0.2 mm or more. A regenerative shaft core obtained from an elastic roll having a shaft core and an elastic layer disposed around the shaft core,
When the total thickness of the elastic layer of the elastic roll is tc,
Around the shaft core, it has only a portion of the elastic layer with a thickness ta,
A reproducing shaft core in which ta ≦ 0.2tc and ta is 0.2 mm or more.

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