JP2009198909A - Method of manufacturing elastic roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make both the preventinon of change in mechanical properties of rubber caused by reaction residual in an elastic roll after being left for a long term and the moldability of the elastic roll compatible. <P>SOLUTION: The elastic roll is formed by applying a liquid silicone rubber material, whose temperature is 0°C to 15°C, whose yield stress under 0°C to 15°C is 20 Pa to 600 Pa and whose H/Vi of the number of mols H in silicon atomic union hydrogen atom to the number of mols Vi in vinyl group is 2.0 to 6.0, on a metal shaft core body 101, whose temperature is 60°C to 160°C, by using a ring shaped coating head. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an elastic roll used as a developing roll, a charging roll or the like of an image forming apparatus such as a printer or a copying machine.

  As an elastic roll used in an image forming apparatus, a metal shaft core and an elastic layer (hereinafter also referred to as “silicone rubber elastic layer”) made of a cured product of a silicone rubber composition covering the peripheral surface thereof. The provided structure is often used. This is because the characteristics (electrical characteristics, elastic characteristics, etc.) of the silicone rubber elastic layer hardly change even when the surrounding environment (temperature, humidity, etc.) changes.

As a conventional manufacturing method of this elastic roll, as described in Patent Document 1, a silicone rubber composition is applied to a metal shaft core (core metal) with an adhesive called a primer, and then dedicated. A method of forming an elastic layer using a metal mold was employed. For forming the elastic layer, compression molding or injection molding is used. However, such a manufacturing method has various problems associated with the use of primers. With respect to such a problem, in Patent Document 1, an elastic roll excellent in adhesion between the core metal and the silicone rubber elastic layer can be obtained without using a primer by using an addition reaction type organopolysiloxane composition. (Paragraph numbers 0002 and 0003).
JP-A-9-174649

  Based on the disclosure of Patent Document 1, the present inventors have conducted various studies on a method for producing an elastic roll using an addition reaction type organopolysiloxane mixture. In the process, in order to further strengthen the adhesion between the silicone rubber elastic layer and the core metal, the number of moles of active hydrogen in the mixture with respect to the vinyl group may be excessive ((H / Vi)> 1). I found it effective. However, in the silicone rubber elastic layer formed by such a mixture, it is inevitable that the vinyl group content decreases. As a result, the rubber elasticity, which is known as the aging phenomenon, may decrease over time.

  Accordingly, an object of the present invention is to provide a method for producing an elastic roll in which the silicone rubber elastic layer has good adhesion to the core metal while suppressing a decrease in elasticity of the silicone rubber elastic layer over time. .

As a result of intensive studies to solve this problem, the present inventors have found that the above object can be well achieved by adjusting all of the following parameters.
(1) Number of moles (H / Vi) of active hydrogen in the addition reaction type organopolysiloxane mixture with respect to the vinyl group.
(2) Temperature at the time of supplying the addition reaction type organopolysiloxane mixture to the surface of the metal shaft core.
(3) The temperature of the shaft core surface.

That is, the method for producing an elastic roll according to the present invention includes:
(1) A liquid addition reaction type silicone rubber mixture in which functional groups for addition reaction are silicon atom-bonded hydrogen atoms and vinyl groups is supplied to the peripheral surface of the metal shaft core body, Forming a coating layer of the addition reaction type silicone rubber layer on the surface;
(2) curing the coating layer to form an elastic layer;
A method for producing an elastic roll having
In the step (1), the addition reaction type silicone rubber mixture having a temperature in the temperature range of 0 ° C. to 15 ° C. is supplied to the peripheral surface of the shaft core having a surface temperature in the range of 60 ° C. to 160 ° C. Including a step of performing, and
The addition reaction type silicone rubber mixture is characterized in that the ratio of the number of moles of silicon-bonded hydrogen atoms to the number of moles of vinyl groups is 2.0 or more and 6.0 or less.

  According to the present invention, an elastic roll that has good adhesion between the shaft core and the elastic layer, and that can maintain good mechanical properties with reduced changes in the mechanical properties of rubber even when left for a long period of time. Can be obtained.

  Hereinafter, the present invention will be described in detail.

  FIG. 1A shows a perspective view of an example of an elastic roll according to the present invention. In FIG. 1 (A), 101 is a shaft core body, and the elastic roll concerning this invention is provided with the elastic layer 102 which consists of the hardened | cured material of the silicone rubber composition around the shaft core body 101. FIG. The shaft core body 101 functions as an electrode and a support member of an elastic roll.

  In the method for producing an elastic roll of the present invention, the temperature of the addition reaction type silicone rubber mixture supplied to the shaft core is set to 0 ° C to 15 ° C. The yield stress of this addition reaction type silicone rubber mixture at 0 ° C. to 15 ° C. is preferably 20 Pa to 600 Pa. Further, H / Vi, which is the ratio of the number of moles of silicon-bonded hydrogen atoms to the number of moles of vinyl groups Vi in the addition reaction type silicone rubber mixture, is 2.0 to 6.0. This liquid addition-reactive silicone rubber mixture is directly applied to the peripheral surface made of metal or alloy of a metal shaft core having a temperature of 60 ° C. to 160 ° C. using a ring-shaped coating head or the like. A reactive silicone rubber composition coating layer (addition reactive silicone rubber coating layer) is formed. The formed coating layer is further cured to obtain an elastic roll as a silicone rubber layer as an elastic layer.

<Description of reason for selecting silicone rubber material>
In the case of an elastic roll used in an electrophotographic system, since it is used in a state where it is always in pressure contact with a member disposed in the periphery, it is required to have low hardness and good deformation recovery. Therefore, a silicone rubber having a moderately low hardness and good deformation recovery is used as the elastic layer forming material. Silicone rubber is available in addition reaction crosslinking type, condensation reaction crosslinking type, and peroxide curing type. Among these, processability is good and dimensional accuracy is stable, and no reaction by-products are generated during the curing reaction. Silicone rubber crosslinked by addition reaction is used.

  An addition reaction type silicone rubber mixture that provides such a silicone rubber comprises an alkenyl group-containing organopolysiloxane (main agent) and an organohydrogenpolysiloxane (curing agent), and further contains a catalyst and other additives. It is a waste.

  The organopolysiloxane having an alkenyl group is a base polymer of a silicone rubber raw material, and the molecular weight thereof is not particularly limited, but the mass average molecular weight (Mw) is 10,000 to 1,000,000, particularly 50,000 to 700,000. It is preferable.

  The alkenyl group of the organopolysiloxane is a site that reacts with the active hydrogen of the organohydrogenpolysiloxane to form a crosslinking point. And as an alkenyl group, a vinyl group and an allyl group with high reaction with active hydrogen are preferable, and a vinyl group is especially preferable.

  The organohydrogenpolysiloxane functions as a crosslinking agent for addition reaction in the curing process, and two or more silicon-bonded hydrogen atoms in one molecule are required. It is preferable that there are more than one. The molecular weight of the organohydrogenpolysiloxane is not particularly limited, and a preferable mass average molecular weight (Mw) is suitably from 1,000 to 10,000. In order to suitably perform the curing reaction, a polymer having a relatively low molecular weight and a weight average molecular weight of 1,000 to 5,000 is preferred.

  The addition reaction type liquid silicone rubber preferably contains a known platinum-based catalyst as a crosslinking catalyst. Examples of the platinum-based catalyst include platinum compounds such as chloroplatinic acid, alcohol compounds of chloroplatinic acid, ether compounds, and complexes with hydrates. Moreover, the transition metal compound which shows a catalytic action in hydrosilylation reaction can also be used as a crosslinking catalyst. The addition amount of the crosslinking catalyst is preferably in the range of 1 ppm or more and 2000 ppm or less in total of platinum atoms or platinum atoms and transition metal atoms with respect to the organopolysiloxane.

<Description of H / Vi>
In the present invention, the ratio (H / Vi) of the number of moles of active hydrogen (H) of the organohydrogenpolysiloxane (curing agent) and the number of moles of vinyl groups (Vi) of the organopolysiloxane (main agent) forming the crosslinking point. ) Is set to 2.0 to 6.0. Usually, a crosslinking point is formed by 1 mol of active hydrogen of the curing agent and 1 mol of vinyl group of the main agent. Therefore, as described above, when the number of moles of active hydrogen is excessive with respect to the number of moles of vinyl groups, in the cured product from the addition reaction type silicone rubber mixture, theoretically, in the silicone rubber after crosslinking. Thus, a curing agent having active hydrogen remains, and no vinyl group remains.

  The remaining curing agent is a relatively low-molecular compound and a highly reactive substance. For these reasons, there are concerns over changes in mechanical properties of the elastic layer over time, such as oozing out from the elastic layer after curing, or by promoting polymerization of the curing agent by reacting with moisture in the air. Is done. In addition, the effect of suppressing the change in elasticity over time due to the reconstruction of the crosslinked structure by the reaction of the remaining vinyl groups cannot be expected.

  Therefore, as will be described later, the inventors of the present invention applied an excess of active hydrogen to the surface of the shaft core body of the addition reaction type silicone rubber mixture in order to actively utilize the active hydrogen for adhesion between the shaft core body and the silicone rubber layer. The temperature at the time of supply and the surface temperature of the shaft core were adjusted. As a result, the active hydrogen was used for adhesion between the shaft core body and the silicone rubber, so that the adhesion between the shaft core body and the elastic layer was improved and the change in mechanical properties of the elastic layer over time was suppressed.

  A hydrogen atom bonded to a silicon atom (active hydrogen) has a high reactivity with a hydroxyl group, and reacts with a functional group (hydroxyl group) present on the metal surface, whereby an addition reaction type silicone rubber layer and an elastic layer obtained therefrom, It is considered that a good adhesion state with the shaft core body can be obtained. The present invention balances the amount of the curing agent consumed in the polymerization reaction and the amount of the curing agent consumed for adhesion to the shaft core so that the remaining amount of active hydrogen in the elastic layer after crosslinking is reduced. It is characterized in that the amount of H / Vi is adjusted in advance. And if H / Vi is the range of 2.0 or more and 6.0 or less, adhesiveness with a shaft core body is fully securable. Further, it is difficult to cause a change with time in the mechanical properties of the elastic layer. This is presumably because a large amount of the curing agent does not remain in the crosslinked elastic layer and a vinyl group remains.

<Description of temperature of silicone rubber material>
The temperature (material temperature) of the addition reaction type silicone mixture, which is a material for forming the coating layer when supplied to the shaft core, is in the range of 0 ° C to 15 ° C. The material temperature referred to here is the temperature of the material in the ring-type coating head immediately before coating, and is measured by a thermometer fixed to the material flow path in the coating head. In the production method of the present invention, since the shaft core body that has been heated in advance is used, the silicone rubber material contacts the shaft core body, and at the same time, heat is removed from the shaft core body, and the material temperature rises. At this time, in order to preferentially use the curing agent for the adhesion reaction with the shaft core body, it is necessary not to raise the material temperature too much. When the material temperature is higher than 15 ° C., the material temperature rises too much due to the heat taken from the shaft core body, and the crosslinking reaction in the material is promoted, so that sufficient adhesion to the shaft core body cannot be obtained. . In addition, the viscosity of the material is too low, and air is easily involved during molding, resulting in bubble defects. When the material temperature is lower than 0 ° C., the viscosity of the material becomes too high, the pressure when the material is discharged from the coating head becomes high, the material pulsates, and the shape of the molded product becomes uneven. End up. When the material temperature of the silicone rubber is in the range of 0 ° C. to 15 ° C., the adhesive with the shaft core body is sufficient, and a molded product with good dimensional accuracy can be obtained.

<Description of Yield Stress of Silicone Rubber Material>
As the addition reaction type silicone mixture which is a material for forming a coating layer used in the production method of the present invention, it is preferable to use a mixture having a yield stress in the range of 20 Pa to 600 Pa. This only needs to satisfy 20 Pa to 600 Pa when the material temperature is in the use range of 0 ° C. to 15 ° C. Yield stress is an index indicating how much fluidity a liquid material exhibits. For example, in the case of a material having a yield value of 100 Pa, the material does not exhibit fluidity when it is subjected to stress less than 100 Pa, but exhibits a solid-like property. However, when stress exceeding 100 Pa is applied to the material For the first time, it exhibits fluidity and exhibits liquid properties. That is, it becomes an index for maintaining the shape when the material is molded on the shaft core. As described above, as one method for giving a liquid material a predetermined yield value, there is a method in which a filler having a cohesive force is mixed and dispersed in the material.

  Examples of such fillers are fumed silica, wet silica, quartz fine powder, diatomaceous earth, carbon black, zinc oxide, basic magnesium carbonate, activated calcium carbonate, magnesium silicate, aluminum silicate, titanium dioxide, talc, Contains mica powder, aluminum sulfate, calcium sulfate and barium sulfate. These can be used alone or in combination of two or more. In order to exert cohesive force, silica fine powder and carbon black having a large specific surface area are preferred. When the yield stress of the material is within the above numerical range, the shape can be kept well because the material is difficult to flow during coating. Therefore, the dimensional accuracy can be improved. Further, when the yield value is 600 Pa or less, streaks are not generated in the molded product.

<Description of temperature range of shaft core>
In the manufacturing method of the present invention, the temperature of the peripheral surface on which the coating layer of the shaft core body is formed is adjusted to a range of 60 ° C to 160 ° C. The temperature of the shaft core means the temperature immediately before the material is applied, and is measured by a non-contact type radiation thermometer attached to the molding apparatus. In the actual process, the surface temperature of the shaft core body changes due to the application of the liquid material, but the setting on the shaft core body temperature control side should be used without changing the temperature setting of the shaft core body before the application of the liquid material. Can do. By making the surface temperature of the shaft core body higher than the material temperature when supplying the addition reaction type silicone rubber mixture, which is a material for forming the coating layer, to the surface of the shaft core body, functional groups present on the surface of the shaft core body ( The reactivity between the hydroxyl group) and the addition reaction type silicone rubber mixture can be increased. As a result, first, the curing agent in the addition reaction type silicone rubber mixture reacts with the core metal. Therefore, the adhesion between the shaft core body and the crosslinked silicone rubber layer becomes stronger. Thereafter, the crosslinking reaction between the main agent and the curing agent in the addition reaction type silicone rubber mixture is promoted by primary curing. When the temperature of the shaft core body is lower than 60 ° C., the shaft core body temperature is rapidly cooled by contact with the material. For this reason, the reactivity with the functional group on the surface of the shaft core is low, and sufficient adhesion to the rubber material cannot be obtained. On the other hand, if the temperature of the shaft core body is higher than 160 ° C., the material temperature rises rapidly, and the moisture in the material reacts with the curing agent and is consumed, so the reactivity with the surface of the shaft core body is poor. Therefore, it is difficult to obtain sufficient adhesion as intended in the present invention. When the temperature of the shaft core body is in the range of 60 ° C. to 160 ° C., sufficient adhesion with the shaft core body can be obtained. Preferably it is the range of 80 to 140 degreeC.

<Description of molding speed range>
In the production method of the present invention, the supply rate of the addition reaction type silicone rubber mixture to the shaft core body is such that the temperature of the addition reaction type silicone rubber mixture supplied to the surface of the metal core is the temperature range described above due to heat conduction from the metal core. It is preferable to adjust so as not to deviate. The speed at which the material is applied is preferably set within a range of 30 mm / sec to 120 mm / sec. Within this speed range, it is possible to avoid that the material applied in the initial stage takes away the heat of the metal core and the adhesiveness with the material of the part to be applied later is insufficient. Further, the material can be discharged stably.

<Description of elastic layer thickness range>
In the present invention, the thickness of the elastic layer is preferably in the range of 1.0 mm to 4.0 mm. The thickness of the coating layer before crosslinking and curing is related to the heat absorption of the shaft core and the remaining of the curing agent. By setting the thickness of the elastic layer within the above range, both good adhesion to the shaft core and stability over time of the mechanical properties of the elastic layer can be achieved.

<Description of shaft core material>
The shaft core used in the production method of the present invention is preferably aluminum, stainless steel, iron, or any alloy thereof, or those plated with chromium or nickel. Among them, stainless steel, iron, various alloys, or those plated on the surface thereof have an appropriate material strength and are preferable for use as a shaft core.

  Here, FIG. 2 shows a schematic explanatory diagram of a ring coater having a ring-type coating head used in the production method of the present invention. In this ring coat machine, a column 2 is attached substantially vertically on a gantry 1, and a precision ball screw 3 is attached substantially vertically from the gantry 1 to the top of the column 2. Reference numeral 15 denotes a linear guide. Two linear guides 15 are attached to the column 2 in parallel with the precision ball screw 3. The LM guide 4 connects the linear guide 15 and the precision ball screw 3, and the rotary motion is transmitted from the servo motor 5 through the pulley 6 so that the LM guide 4 can move up and down. A ring-shaped coating head 8 that applies a liquid material for forming a coating layer to the peripheral surface of the shaft core body 101 is attached to the column 2. Furthermore, a bracket 7 is attached to the LM guide 4, and a shaft core lower holding shaft 9 that holds and fixes the shaft core body 101 is attached to the bracket 7 substantially vertically. Further, the central axis of the shaft core upper holding shaft 10 that holds the shaft core body 101 of the opposite roll is attached to the upper part of the bracket 7, and the shaft core upper holding shaft 10 faces the shaft core lower holding shaft 9. And it arrange | positions so that it may become substantially concentric, and the shaft core body is hold | maintained.

  The center axis of the ring-shaped coating head 8 is supported so as to be parallel to the moving direction of the shaft core lower holding shaft 9 and the shaft core upper holding shaft 10. Further, when the shaft core lower holding shaft 9 and the shaft core upper holding shaft 10 are moved up and down, the central axis of the discharge port formed as an annular slit opened inside the coating head 8 and the shaft core lower holding shaft 9 are arranged. In addition, the center axis of the shaft core holding shaft 10 is adjusted to be substantially concentric.

  With such a configuration, the central axis of the discharge port formed in the annular slit of the coating head 8 can be aligned substantially concentrically with the central axis of the shaft core 101, and the inner peripheral surface of the ring-shaped coating head and the above-mentioned A uniform gap is formed between the shaft core body 101 and the peripheral surface.

  The liquid material supply port 11 is connected to a material supply valve 13 via a pipe 12. The material supply valve 13 includes a material temperature adjustment unit 14 in front of the material supply valve 13 to adjust the temperature of the liquid material. At this time, if necessary, a mechanism for adjusting the temperature of the material may be added by providing a flow path for flowing the cooling water in the coating head 8 and using a chiller to flow the cooling water. Further, a non-display mixing mixer, a material supply pump, a material fixed amount discharge device, a material tank, and the like are provided in front of the material temperature control unit 14 so that a fixed amount (a constant amount per unit time) of liquid rubber can be discharged. A predetermined amount of the silicone rubber composition is weighed from the material tank by a material dispensing device and mixed by a mixing mixer. Thereafter, the silicone rubber composition mixed by the material supply pump is sent from the material supply valve 13 to the supply port 11 via the pipe 12.

  The liquid material fed from the supply port 11 passes through the flow path in the ring type coating head 8 and is discharged from the nozzle of the ring type coating head 8. At this time, the material temperature in the coating head 8 is measured by a material thermometer 16 (detailed diagram: FIG. 3), and the temperature is fed back to the material temperature control unit 14 to adjust the temperature. In order to make the wall thickness of the coating layer constant, the discharge amount from the ring-shaped coating head nozzle and the supply amount from the material supply pump are made constant, and the shaft core body 101 held in the vertical direction (the shaft core body) (In the direction of the central axis). Thus, the shaft core body 101 moves in the axial direction relative to the coating head 8, and has a cylindrical shape (roll shape) made of the addition reaction type silicone rubber composition on the peripheral surface of the shaft core body 101. An uncured material covering layer 102 'is formed. At this time, the temperature of the shaft core body 101 heated in advance is measured by a fixed shaft core body thermometer 17 and is molded when it is at a preferable temperature. When a non-contact thermometer is used as the shaft core thermometer, it is necessary to concentrate the spot on the apex of the curved surface of the shaft core body and set the reflectance appropriately.

  In the next step, the uncured coating layer is heat-treated by infrared heating and cured to obtain an elastic roll as an elastic layer. The surface of the uncured coating layer has adhesiveness. For this reason, the heat treatment is preferably a non-contact, simple apparatus, and infrared heating that can uniformly heat the uncured layer of the silicone rubber composition in the longitudinal direction. At this time, heat treatment is uniformly performed in the circumferential direction by fixing the infrared heating device and rotating the axial body provided with the cylindrical (roll-shaped) coating layer in the circumferential direction. The heat treatment temperature of the coating layer is preferably 100 ° C. or more and 250 ° C. or less at which the curing reaction starts although it depends on the addition reaction type silicone rubber composition used.

  Here, for the purpose of stabilizing the physical properties of the elastic layer after curing and sufficient reaction in the elastic layer, secondary curing such as heat treatment may be further performed on the elastic layer.

  The elastic roll according to the present invention has good dimensional accuracy, mechanical property uniformity, and temporal stability of the elastic layer. The elastic roll according to the present invention is used for applications that require elastic properties such as an electrophotographic developing roll, a charging roll, a transfer roll, a supply roll, a driving roll, a transport roll, a cleaning roll, a coating roll, and a fixing roll. Is possible.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, these do not limit this invention at all. First, various evaluation and measurement methods performed in Examples will be described.

<Elastic layer thickness measurement method>
A sharp blade was vertically placed at three locations that divide the elastic layer forming portion of the elastic roll into four equal parts in the longitudinal direction to reach the shaft core (see FIG. 1B). Next, a blade was similarly inserted at a position where the width was about several millimeters to cut out the elastic layer, and three samples were taken out in the longitudinal direction. Each sample was measured using a video microscope (trade name: VHX100; manufactured by Keyence Corporation), and the average value thereof was used as the thickness of the elastic layer.

<Yield stress of liquid rubber material for elastic layer>
The yield stress of the liquid rubber material for the elastic layer is the storage elastic modulus G ′ and loss elastic modulus G ″ measured by the following operations using a viscoelasticity measuring device “RS600” (trade name) manufactured by Haake. It was measured by obtaining the stress value at the intersecting point.

  About 1 g of the mixed solution of A and B is sampled and placed on the sample stage of the viscoelasticity measuring device, and the cone plate (diameter 35 mm, inclination angle 1 °) is gradually approached and measured at a position of about 50 μm from the sample stage. A gap was set. At that time, the material extruded around was removed cleanly so as not to affect the measurement. Next, the temperature of the platen was set to the material temperature at the time of molding, and after setting the sample, it was left for 10 minutes, and then the measurement was started. The stress applied to the sample was started from 0.00 Pa and varied over 180 seconds from 50000 Pa (frequency is 1 Hz), and changes in storage elastic modulus G ′, loss elastic modulus G ″ and phase difference tan δ were measured at 32 points. The modulus G ′ is a constant value in the first linear viscoelastic region, but changes thereafter. The relationship between the stress value and the storage elastic modulus G ′ and the loss elastic modulus G ″ is shown in a graph, and the storage elastic modulus G ′ and The stress value at the point where the loss elastic modulus G ″ intersects was read and taken as the yield stress.

[Example 1]
(Preparation of silicone rubber composition)
A material obtained by mixing the following materials with a planetary mixer for 1 hour was used as a base material for liquid silicone rubber.
-Dimethylpolysiloxane having a weight average molecular weight of 100,000 with vinyl groups substituted at both ends (vinyl group Vi content 0.15 mass%): 100 parts by mass-Carbon black (trade name: Raven890; manufactured by Columbian Chemicals Campany): 5 .7 parts by mass,
Carbon black (trade name: Raven410; manufactured by Columbian Chemicals Campany): 7.9 parts by mass.

  The base material was mixed with 10 ppm of isopropyl alcohol solution of 2% by weight of chloroplatinic acid as a curing catalyst and mixed with dimethylpolysiloxane for 30 minutes using a planetary mixer to prepare solution A.

  In addition, the above base material was blended so that H that binds organohydrogensiloxane to Si atoms was doubled with respect to 1 mol of the vinyl group of the dimethylpolysiloxane, and mixed with a planetary mixer for 30 minutes. It was set as B liquid.

  The liquid A and the liquid B were mixed at a mass ratio of 1: 1 to obtain a liquid material for forming an elastic roll coating layer. The yield stress of the liquid material was 190 Pa.

(Create elastic roll)
2 is an iron shaft core having an outer diameter of 6 mm on the shaft core holding shaft (the shaft core upper holding shaft 10 and the shaft core lower holding shaft 9) of the ring coater having a ring type coating head having an inner diameter of 12 mm shown in FIG. A (SUM material) with nickel plating (Ni) was set vertically. The shaft core body was moved by vertically raising the shaft core body holding shaft (60 mm / sec). At this time, the temperature of the shaft core was 100 ° C. In addition, the liquid material is discharged at 5040 mm ³ / sec, and a coating layer made of an addition reaction type silicone rubber composition and formed into a cylindrical shape (roll shape) is formed on the outer peripheral surface of the shaft core. A roll having a cured coating layer (hereinafter, an uncured roll) was produced. At this time, the material temperature in the coating head was 10 ° C.

  The uncured roll is rotated at 60 rpm around the shaft core body, and infrared rays (output 1000 W) are applied to the surface of the uncured coating layer with an infrared heating lamp (trade name: HYL25; manufactured by HYBEK Co., Ltd.) for 4 minutes. Irradiated to cure. Note that the distance between the surface of the molded product layer and the lamp during infrared irradiation was 60 mm, and the temperature of the molded product layer surface was 200 ° C. Thereafter, for the purpose of stabilizing the physical properties of the elastic layer obtained by curing, secondary curing was performed at 200 ° C. for 4 hours in an electric furnace to obtain an elastic roll 1 having a diameter of 12 mm.

(Preparation of roll for image evaluation)
The following materials and MEK were mixed and dispersed in a sand mill for 1 hour.
Polyurethane polyol prepolymer (trade name: Takelac TE5060; manufactured by Mitsui Takeda Chemical Co., Ltd.): 100 parts by mass
・ Isocyanate (trade name: Coronate 2521; manufactured by Nippon Polyurethane Co., Ltd.): 77 parts by mass
Carbon black (trade name: MA100; manufactured by Mitsubishi Chemical Corporation): 24 parts by mass.

  After dispersion, MEK was further added to adjust the solid content in the range of 20% by mass to 30% by mass so that the film thickness after coating and drying was 20 μm to obtain a coating material for the surface layer.

  The elastic roll 1 was immersed in this paint, the paint was applied to the elastic layer, and then naturally dried to form a paint film. Subsequently, it heated at 140 degreeC for 60 minute (s), the coating film was hardened, and the surface layer was formed. Thus, an image evaluation roll 1 was obtained.

<Evaluation of imageability (change with time) of elastic roll>
Two electrophotographic process cartridges (nominal life 6000 sheets, A4 size, printing rate 5%) of an electrophotographic image forming apparatus (trade name: HP Color LaserJet 3700; manufactured by HP Japan) were prepared (hereinafter referred to as “electrophotographic process cartridge”). I ”and“ electrophotographic process cartridge II ”). Each of the electrophotographic process cartridges I and II was incorporated with the image evaluation roll 1 and filled with black toner. The electrophotographic process cartridge I was left in an environment of a temperature of 23 ° C. and 55% RH for 24 hours or more, and then mounted on an electrophotographic image forming apparatus to output an electrophotographic image (solid image and halftone image). This is the initial image. On the other hand, the electrophotographic process cartridge II was left for 3 months in a high-temperature and high-humidity environment (temperature 40 ° C., humidity 95% RH) for accelerating tests by simulating long-term storage. Next, it was left for 24 hours in an environment of a temperature of 23 ° C. and 55% RH. Thereafter, the electrophotographic process cartridge 102 was mounted on an electrophotographic image forming apparatus, and images (solid image and halftone image) were output. This is an image after being left for a long time.

The output image was visually observed, and the level of transverse stripes was evaluated according to the following criteria.
Rank 1: No horizontal stripes Rank 2: Horizontal stripes are found on either the left or right edge of the image and are not connected across the image Rank 3: Horizontal stripes extend from the right edge to the left edge of the image Clearly visible rank 4: The horizontal stripes are clearly visible from the right edge to the left edge of the image and are observed over the entire image in the roll cycle. Furthermore, the rank difference between the initial image and the image after being left for a long time Was regarded as a change with time, and evaluated according to the following criteria.
A: Rank difference None B: Rank difference 1 Within allowable limit C: Rank difference 2 Change too large outside allowable limit D: Rank difference 3 Change too large outside allowable limit <formability>
1000 elastic rolls were formed by the above-mentioned method, and the number of defects that occurred as defects (runout, uneven outer diameter, bubble generation, streaks, adhesion failure) was investigated. evaluated.
A: defective rate of less than 1% B: defective rate of 1% or more and less than 3% and within allowable limit C: defective rate of 3% or more and less than 30% and out of allowable limit D: defective rate of 30% or more and out of allowable limit [Example 2 ]
The blending amount of the organohydrogensiloxane of the B liquid in Example 1 was changed so that H bonded to Si atoms was four times as much as 1 mol of the vinyl group of the dimethylpolysiloxane. Other than that was carried out similarly to Example 1, and prepared the silicone rubber composition which concerns on a present Example. The yield stress of this silicone rubber composition was 150 Pa. Using this silicone rubber composition, an elastic roll 2 and an image evaluation roll 2 were prepared and evaluated in the same manner as in Example 1.

Example 3
The blending amount of the organohydrogensiloxane in the B liquid in Example 1 was changed so that H bonded to Si atoms was 6 times the 1 mol of the vinyl group of the dimethylpolysiloxane. Other than that was carried out similarly to Example 1, and prepared the silicone rubber composition which concerns on a present Example. The yield stress of this silicone rubber composition was 150 Pa. Using this silicone rubber composition, an elastic roll 2 and an image evaluation roll 2 were prepared and evaluated in the same manner as in Example 1.
Example 4
An elastic roll 3 and an image evaluation roll 3 were prepared and evaluated in the same manner as in Example 1 except that the temperature of the liquid material during coating in Example 1 was changed to a temperature of 0 ° C. (yield stress 250 Pa).
Example 5
The temperature of the liquid material at the time of coating in Example 1 was changed to a temperature of 15 ° C. (yield stress 170 Pa). In addition, an iron shaft core (SUM material) for molding that was chrome plated (Cr) was used. Otherwise, the elastic roll 3 and the image evaluation roll 3 were produced and evaluated in the same manner as in Example 1.
Example 6
In Example 1, the base material was changed to the following composition. Otherwise, a silicone rubber composition was prepared in the same manner as in Example 1. The yield stress was 20 Pa.
-A dimethylpolysiloxane having a mass average molecular weight of 100,000 substituted with vinyl groups at both ends (vinyl group Vi content 0.15% by mass): 100 parts by mass,
Carbon black (Raven860, manufactured by Columbian Chemicals Campany): 3.8 parts by mass
Carbon black (Raven410, manufactured by Columbian Chemicals Campany): 3.0 parts by mass.

  The elastic roll 6 and the image evaluation roll 6 were formed in the same manner as in Example 1 except that the above silicone rubber composition was used and an iron (SUM material) shaft core subjected to chrome plating (Cr) was used. Prepared and evaluated.

Example 7
In Example 1, the base material was changed to the following composition. Otherwise, a silicone rubber composition was prepared in the same manner as in Example 1. The yield stress of the obtained silicone rubber composition was 600 Pa.
-A dimethylpolysiloxane having a mass average molecular weight of 100,000 substituted with vinyl groups at both ends (vinyl group Vi content 0.15% by mass): 100 parts by mass,
Carbon black (Raven 3600, manufactured by Columbian Chemicals Campany): 11.4 parts by mass
Carbon black (Raven500, manufactured by Columbian Chemicals Campany): 5.0 parts by mass.
An elastic roll 7 and an image evaluation roll 7 were prepared and evaluated in the same manner as in Example 1 except that the above silicone rubber composition was used and a stainless steel (SUS304) shaft core was used.
Example 8
In Example 1, a shaft core body made of stainless steel (SUS304) was used, and the temperature of the shaft core body at the time of creating the elastic roll was changed to 60 ° C. Otherwise, the elastic roll 8 and the image evaluation roll 8 were produced and evaluated in the same manner as in Example 1.
Example 9
An elastic roll 9 and an image evaluation roll 9 were prepared and evaluated in the same manner as in Example 8 except that the temperature of the shaft core at the time of creating the elastic roll was 160 ° C.
Example 10
In Example 1, various conditions at the time of creating the elastic roll were changed as follows. Otherwise, the elastic roll 10 and the image evaluation roll 10 were produced and evaluated in the same manner as in Example 1.
Inner diameter of coating head: 8mm,
Ascent speed of shaft holding shaft; 120 mm / s,
Discharge rate of silicone rubber composition; 3360 mm ³ / sec,
Shaft core temperature: 80 ° C,
Shaft core: Made of aluminum (Al).
Example 11
In Example 1, various conditions at the time of creating the elastic roll were changed as follows. Otherwise, the elastic roll 11 and the image evaluation roll 11 were produced and evaluated in the same manner as in Example 1.
Inner diameter of coating head: 14 mm,
Ascending speed of shaft core holding shaft; 30 mm / s,
Discharge rate of silicone rubber composition; 3360 mm ³ / sec,
Shaft core temperature; 140 ° C
Shaft core: Made of stainless steel (SUS304).

[Comparative Example 1]
The B liquid organohydrogensiloxane in Example 1 was blended in an amount of 1.0 part by mass so that the amount of H bonded to Si atoms was 1 time with respect to 1 mol of the vinyl group of the dimethylpolysiloxane. Other than that was carried out similarly to Example 1, and prepared the silicone rubber composition which concerns on this comparative example. The yield stress of this silicone rubber composition was 150 Pa. Using this silicone rubber composition, an elastic roll 12 and an image evaluation roll 12 were prepared and evaluated in the same manner as in Example 1.
[Comparative Example 2]
The organohydrogensiloxane of the liquid B in Example 1 was blended so that the amount of H bonded to Si atoms was 10 times that of 1 mol of the vinyl group of the dimethylpolysiloxane. Otherwise, a silicone rubber composition was prepared in the same manner as in Example 1. The yield stress of this silicone rubber composition was 150 Pa. Using this silicone rubber composition, an elastic roll 13 and an image evaluation roll 13 were prepared and evaluated in the same manner as in Example 1.
[Comparative Example 3]
An elastic roll 14 and an image evaluation roll 14 were prepared and evaluated in the same manner as in Example 1 except that the temperature of the material during coating in Example 1 was changed to −5 ° C.
[Comparative Example 4]
An elastic roll 15 and an image evaluation roll 15 were prepared and evaluated in the same manner as in Example 1 except that the temperature of the material at the time of coating in Example 1 was 20 ° C.
[Comparative Examples 6 and 7]
In Example 1, the elastic roll 16, the image evaluation roll 16, the elastic roll 17, and the image evaluation were performed in the same manner as in Example 1 except that the temperature of the shaft core at the time of creating the elastic roll was changed to 25 ° C. and 180 ° C. A roll 17 was prepared and evaluated.

  Table 1 below shows conditions for preparing image evaluation rolls according to the above Examples and Comparative Examples. The evaluation results of each image evaluation roll are shown in Table 2 below.

(A) is a perspective view of an example of the elastic roll of this invention. (B) is a figure which shows operation in the measurement of the thickness of an elastic layer. It is a schematic explanatory drawing of a ring coat machine. It is sectional drawing of a coating head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Shaft core body 102 Elastic body 102 'Covering layer 1 Base 2 Column 3 Ball screw 4 LM guide 5 Servo motor 6 Pulley 7 Bracket 8 Coating head 9 Shaft core lower holding shaft 10 Shaft core upper holding shaft 11 Supply port 12 Piping 13 Material Supply Valve 14 Material Temperature Control Unit 15 Linear Guide 16 Material Thermometer 17 Shaft Core Thermometer

Claims (3)

(1) A liquid addition reaction type silicone rubber mixture in which functional groups for addition reaction are silicon atom-bonded hydrogen atoms and vinyl groups is supplied to the peripheral surface of the metal shaft core body, Coating the surface with an addition reaction type silicone rubber layer;
(2) curing the addition reaction type silicone rubber layer to form an elastic layer;
A method for producing an elastic roll having
In the step (1), the addition reaction type silicone rubber mixture having a temperature in the temperature range of 0 ° C. to 15 ° C. is supplied to the peripheral surface of the shaft core having a surface temperature in the range of 60 ° C. to 160 ° C. Including a step of performing, and
A method for producing an elastic roll, wherein the ratio of the number of moles of silicon-bonded hydrogen atoms to the number of moles of vinyl groups in the addition reaction type silicone rubber mixture is 2.0 or more and 6.0 or less.   The method for producing an elastic roll according to claim 1, wherein the temperature of the shaft core is in the range of 80C to 140C.   The method for producing an elastic roll according to claim 1 or 2, wherein the shaft core is obtained by plating aluminum, stainless steel, iron, or any alloy thereof, or chromium or nickel.