JP2015033789A - Method and apparatus for production of rubber roll and rubber roll production program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress of deviation of the position giving the maximum outside diameter relative to the axial-direction central position of a core metal, in producing a crown-shaped rubber roll in which the axial-direction central side is thicker than both end sides.SOLUTION: In a method of producing a rubber roll, a rubber material G is extruded in a cylindrical form; a core metal 22 is charged; and a rubber roll part 56 is taken out. Taking the axial-direction total length of the core metal 22 as 1, increase and decrease of the charging speed V2 of the core metal 22 are set so as to get the lowest in a specified range M of the charging-direction length of the core metal 22 from the tip position of 0.30-0.48, and the maximum outside diameter is formed in the axial-direction central part of the core metal 22, suppressing deviation of the position giving the maximum outside diameter of a rubber roll 70 in the axial direction of the core metal 22 relative to the central position of the core metal 22.

Description

  The present invention relates to a rubber roll manufacturing method, a rubber roll manufacturing apparatus, and a rubber roll manufacturing program.

  The rubber roll manufacturing method of Patent Document 1 uses a crosshead extrusion device to stabilize the supply amount of unvulcanized rubber material at a set amount in a rubber roll manufacturing method in which the outer shape is a crown shape. And the rubber roll manufacturing method of patent document 1 changes the moving speed of the metal core in a die nozzle by the site | part of the length direction of a metal core, and changes the outer peripheral diameter of a rubber roll to the length direction.

  In the rubber roll manufacturing method of Patent Document 2, the curvature A of the speed change curve decelerating from the front end to the center of the core metal shaft and the speed change accelerating from the center to the rear end of the core metal shaft. The ratio (A / B) with the curvature B of the curve is in the range of 1.1 to 1.3.

Japanese Patent Laid-Open No. 2003-300279 JP 2008-052025 A

  The present invention provides a rubber roll manufacturing method capable of suppressing the position of the maximum outer diameter from deviating from the central position in the axial direction of the core metal when manufacturing a crown-shaped rubber roll whose axial center side is thicker than both end sides, It is an object to obtain a rubber roll manufacturing apparatus and a rubber roll manufacturing program.

  The rubber roll manufacturing method according to claim 1 of the present invention includes a first step of extruding an unvulcanized rubber material into a cylindrical shape, and a step of feeding a core metal into the rubber material, the axial length of the core metal being The feed speed is set so that the feed speed of the core bar is the slowest at a specific position within a range of 0.30 to 0.48 in length in the feed direction of the core bar. A second step of feeding the cored bar into the rubber material while decreasing and increasing the amount, and a third step of taking out a rubber roll part in which the outer peripheral surface of the cored bar is covered with the rubber material.

  In the rubber roll manufacturing method according to claim 2 of the present invention, both ends of the core metal are sealed with the rubber material.

  The rubber roll manufacturing apparatus according to claim 3 of the present invention includes an extruding unit that extrudes an unvulcanized rubber material into a cylindrical shape, and a feeding unit that feeds a metal core into the center of the rubber material extruded by the extruding unit. The length from the tip position in the feeding direction of the cored bar is defined as taking out means for taking out a rubber roll part in which the outer peripheral surface of the cored bar is covered with the rubber material, and the axial length of the cored bar being 1, Control means for controlling the decrease and increase of the feeding speed of the cored bar by the feeding means so that the feeding speed of the cored bar becomes the slowest at a specific position within a range of 0.30 or more and 0.48 or less; Have

  A rubber roll manufacturing program according to claim 4 of the present invention is a program for causing a computer to function as the control means constituting the rubber roll manufacturing apparatus according to claim 3.

  According to the first aspect of the present invention, when manufacturing a crown-shaped rubber roll whose axial center side is thicker than the both end sides, the position where the maximum outer diameter is at the position where the feeding speed is the slowest at the axial center position is a cored bar. It is possible to suppress deviation from the axial center position.

  The invention according to claim 2 is such that, even when both ends of the cored bar are sealed with a rubber material, the position where the maximum outer diameter is the center in the axial direction of the cored bar is compared with the configuration in which the feeding speed is slowest at the axially central position. Deviation from the position can be suppressed.

  According to the invention of claim 3, when manufacturing a rubber roll having a crown shape whose axial center part is thicker than both end parts, the position where the maximum outer diameter is the center is compared with the configuration in which the feeding speed is slowest at the axial center position. Deviation from the central position in the axial direction of the gold can be suppressed.

  According to the invention of claim 4, when manufacturing a rubber roll having a crown shape whose axial center is thicker than both ends, the position where the maximum outer diameter is the center is compared with the configuration in which the feeding speed is slowest at the axial center. Deviation from the central position in the axial direction of the gold can be suppressed.

It is sectional drawing which shows the structure of the rubber roll manufacturing apparatus which concerns on this embodiment. It is a block diagram of the control part concerning this embodiment. (A) It is a schematic diagram of the metal core which concerns on this embodiment. (B) It is sectional drawing of the rubber roll which concerns on this embodiment. (C) It is a schematic diagram of the rubber roll which concerns on this embodiment. It is a graph which shows the change with respect to the axial direction position of the feeding speed of the metal core concerning this embodiment. It is a flowchart which shows an example of the manufacturing program of the rubber roll which concerns on this embodiment. (A), (B), (C) It is sectional drawing which shows the state from which the metal core which concerns on this embodiment is sent into a rubber material, and is taken out. (A), (B) It is sectional drawing which shows the state from which the rubber roll part which concerns on this embodiment is taken out by the extraction part. (A), (B), (C) It is sectional drawing which shows the state which presses the hollow part which concerns on this embodiment with a pressing member. It is a graph which shows the profile of the external shape of the rubber roll which concerns on this embodiment.

  An example of a rubber roll manufacturing method, a rubber roll manufacturing apparatus, and a rubber roll manufacturing program according to the present embodiment will be described. The rubber-coated shaft body (hereinafter referred to as “rubber roll”) manufactured by the rubber roll manufacturing apparatus, the rubber roll manufacturing method, and the rubber roll manufacturing program according to the present embodiment is used as a charging roll as an example. Although not shown, the charging roll rotates in contact with the photoreceptor of the image forming apparatus and charges the outer peripheral surface of the photoreceptor.

  As shown in FIG. 1, a rubber roll manufacturing apparatus 10 as an example of the present embodiment is an example of a discharge unit 12 that discharges a rubber material G, and an extraction unit that is disposed below the discharge unit 12 and takes out a rubber roll unit 56 described later. And a take-out portion 16. Further, the rubber roll manufacturing apparatus 10 has a pressing portion 14 disposed between the discharge portion 12 and the extraction portion 16.

<Discharge unit>
The discharge unit 12 is constituted by a so-called cross head die. The discharge unit 12 includes a rubber material supply unit 18 that supplies an unvulcanized rubber material G, and an extrusion unit 20 as an example of an extrusion unit that extrudes the rubber material G supplied from the rubber material supply unit 18 into a cylindrical shape. And have. Furthermore, the discharge part 12 has a feeding part 24 as an example of a feeding means for feeding the cored bar 22 into the central part of the rubber material G extruded from the pushing part 20 in a cylindrical shape.

(Rubber material supply unit)
The rubber material supply unit 18 is provided with a screw 28 rotatably inside a cylindrical main body 26 that extends in the illustrated horizontal direction. The screw 28 is rotationally driven by a supply motor 30 with the illustrated lateral direction as an axial direction. The operation of the supply motor 30 is controlled by the control unit 100 described later. In addition, on the supply motor 30 side of the main body portion 26, a charging port 32 for charging the rubber material G is provided. Thereby, the rubber material G introduced from the insertion port 32 is supplied toward the extrusion unit 20 while being kneaded by the screw 28 inside the main body 26. In the rubber material supply unit 18, the supply speed of the rubber material G is adjusted by adjusting the rotational speed of the screw 28.

(Rubber material)
The rubber material G contains a rubber material, a processing aid, a conductive agent, a plasticizer, a vulcanization accelerator, and the like. In the present embodiment, epichlorohydrin rubber is used as an example of the rubber material, and carbon black is used as an example of the conductive agent. Specific examples of each material will be described later.

  The rubber material is not limited to epichlorohydrin rubber, but isoprene rubber, chloroprene rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin- Examples include ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and blend rubbers thereof. Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR, and blended rubbers thereof are preferably used. These rubber materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used. Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; tin oxide, indium oxide, titanium oxide And various conductive metal oxides such as tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution; and the like.

  Examples of the ionic conductive agent include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium, perchlorates and chlorates of alkaline earth metals, and the like.

  These conductive agents may be used alone or in combination of two or more. There is no restriction | limiting in particular in the addition amount of a electrically conductive agent. In the case of an electronic conductive agent, it is preferably in the range of 1 to 40 parts by mass, more preferably in the range of 10 to 30 parts by mass with respect to 100 parts by mass of the rubber material. More preferably, it is in the range of 15 to 25 parts by mass. In the case of an ionic conductive agent, the range is preferably 0.1 parts by weight or more and 5.0 parts by weight or less, and 0.5 parts by weight or more and 3.0 parts by weight or less with respect to 100 parts by weight of the rubber material. It is more preferable that

(Extruded part)
The extrusion unit 20 includes a cylindrical case 34 connected to the rubber material supply unit 18, a columnar mandrel 36 disposed in the center of the case 34, and a discharge head 38 disposed below the mandrel 36. Have.

  The mandrel 36 is held by a holding member 40 attached to the upper side of the case 34. Further, the discharge head 38 is held by a holding member 42 attached to the lower side of the case 34. The rubber material G is annular between the outer peripheral surface of the mandrel 36 (in part, the outer peripheral surface of the holding member 40) and the inner peripheral surface of the holding member 42 (in part, the inner peripheral surface of the discharge head 38). An annular flow path 44 that flows in a (cylindrical) shape is formed.

  Further, an insertion hole 46 into which the cored bar 22 is inserted is formed in the center of the mandrel 36 with the vertical direction shown in the figure as the axial direction. Furthermore, the lower part of the mandrel 36 has a tapered shape toward the lower end. A lower region of the lower portion of the mandrel 36 is a joining portion 48 where the core metal 22 supplied from the insertion hole 46 and the rubber material G supplied from the annular flow path 44 merge. That is, in the extruding part 20, the rubber material G is pushed out in a cylindrical shape toward the joining part 48, and the cored bar 22 is fed into the central part of the rubber material G pushed out in the cylindrical shape.

  Here, the rubber material G has an extrusion speed V1 [mm / s] (see FIG. 6A) when it flows through the joining portion 48 and is extruded from the extrusion portion 20 without the cored bar 22. Yes. That is, the extrusion speed V <b> 1 is a speed when the rubber material G is extruded by the rotation of the screw 28 without the cored bar 22.

(Sending part)
The feeding unit 24 has a roll pair 50 disposed above the mandrel 36. A plurality of pairs of rolls 50 (three pairs as an example) are provided, and a roll on one side of each pair of rolls 50 is connected to a drive roll 54 via a belt 52. Then, the drive roll 54 is rotated at a rotational speed (infeed of the core metal 22) by a control unit 80 as an example of a control unit that controls the decrease and increase in the feeding speed V2 [mm / s] of the core metal 22 by the feeding unit 24. Speed) is controlled.

  Specifically, the drive roll 54 is rotationally driven by the drive motor 84. The operation of the drive motor 84 is controlled by the motor driver 82. Further, the operation of the motor driver 82 is controlled by the control unit 80. As a result, when the drive roll 54 is driven by the drive motor 84, the cored bar 22 sandwiched by each pair of rolls 50 is sent toward the insertion hole 46 of the mandrel 36.

(Control part)
As shown in FIG. 2, the control unit 80 includes a computer as an example. The control unit 80 is set with a rubber roll manufacturing program to be described later for causing the computer to function as an example of a control unit.

  Specifically, the control unit 80 includes a CPU (Central Processing Unit) 80A, a ROM (Read Only Memory) 80B, a RAM (Random Access Memory) 80C, and a nonvolatile memory 80D. The control unit 80 has a configuration in which a CPU 80A, a ROM 80B, a RAM 80C, a nonvolatile memory 80D, and an input / output interface (I / O) 80E are connected to each other via a bus 80F.

  A motor driver 82 is electrically connected to the input / output interface 80E, and the motor driver 82 is electrically connected to the drive motor 84. In this case, for example, a later-described rubber roll manufacturing program is written in the ROM 80B, and the CPU 80A reads the program to control the motor driver 82. Note that the nonvolatile memory 80D may be connected to the outside of the control unit 80 (computer) via the input / output interface 80E, and may be an external storage device such as a memory card, for example.

  As shown in FIG. 1, the cored bar 22 has a predetermined length. Then, the rear core bar 22 (upward in the drawing) sent by the roll pair 50 pushes the front core bar 22 present in the insertion hole 46 of the mandrel 36, and the front core bar 22 is taken out by the take-out portion 16. As a result, the plurality of core bars 22 sequentially move in the insertion hole 46. Further, the drive of the drive roll 54 is temporarily stopped when the front end of the front cored bar 22 is positioned at the tip (lower end) of the mandrel 36, and at the junction 48 below the mandrel 36, The cored bar 22 is fed at intervals.

  Thus, in the discharge part 12, the rubber material G is extruded cylindrically in the junction part 48, and the cored bar 22 is sequentially sent in the center part of the rubber material G at intervals. As a result, the rubber roll portion 56 in which the outer peripheral surface of the core bar 22 is covered with the rubber material G and the hollow portion 58 in which the space between the core bars 22 is hollow are alternately discharged from the discharge head 38. ing. Note that a primer (not shown) is applied in advance to the outer peripheral surface of the cored bar 22 in order to improve the adhesiveness with the rubber material G.

  Here, the feeding speed V2 of the metal core 22 by the feeding section 24 is set to be higher than, for example, an extrusion speed V1 of the rubber material G and a later-described ejection speed V3 of the rubber roll section 56 by the ejection section 16. .

<Pressing part>
The pressing part 14 has a pair of semi-cylindrical pressing members 60. The pair of pressing members 60 are disposed to face each other so as to sandwich the rubber roll portion 56 discharged from the discharge portion 12. Each pressing member 60 is formed with a protrusion 62 that protrudes toward the center. Each pressing member 60 is movable in the horizontal direction and vertical direction shown in the figure by a drive mechanism (not shown).

<Extraction department>
The extraction part 16 has a pair of semi-cylindrical extraction members 64. The pair of extraction members 64 are disposed to face each other so as to sandwich the rubber roll portion 56 discharged from the discharge portion 12. Each extraction member 64 is formed with a grip portion 66 having a shape corresponding to the outer peripheral surface shape of the rubber roll portion 56. Each extraction member 64 can be moved in the horizontal direction and the vertical direction in the figure by a drive mechanism (not shown). The speed at which the rubber roll portion 56 is taken out (pulled out) by the takeout member 64 is the takeout speed V3 [mm / s].

(Setting of feeding speed)
Next, the setting of the feeding speed V2 of the cored bar 22 will be described.

  The charging roll (not shown) is rotated while being pressed against the rotating photoconductor. At this time, if the contact width (nip width) between the charging roll and the photoconductor is not uniform in the axial direction, the electric field strength becomes non-uniform in the axial direction, which may cause uneven charging. As a method for aligning the nip area, it is known that the outer shape of the charging roll is a crown shape (a shape in which the outer diameter on the axial center side is larger than the outer diameters on both ends).

  As a method of manufacturing the crown-shaped rubber roll, there is a method of changing the feeding speed V2 of the cored bar 22 in the axial direction while stabilizing the extrusion speed V1 of the rubber material G within an allowable range. Furthermore, as a method of manufacturing a crown-shaped rubber roll, the rubber whose compression speed becomes slower from the axial front end to the center of the core metal 22 and whose movement speed becomes faster from the center to the rear end is shown. There is a method of changing the speed control pattern depending on the tension.

  Here, with respect to the feed speed V2 of the cored bar 22, when the speed control pattern is changed at the axial center position of the cored bar 22, the phenomenon that the maximum outer diameter position is biased toward the rear end side with respect to the axial center position. confirmed. This phenomenon is considered to be due to the following reason.

  The rubber material G in contact with the cored bar 22 has a high flow velocity and follows the feed speed control of the cored bar 22, but the rubber material G flowing near the die wall surface of the junction 48 is a rubber material near the cored bar 22. Compared to G, the flow velocity is slower and it is difficult to follow speed control. For this reason, for the speed control of the cored bar 22 whose axial center position is the slowest, the wall thickness is the thickest on the rear end side than the central position, and the crown center is biased toward the rear end side (in the axial direction). It will be asymmetric).

  For this reason, with respect to the feeding speed V2 of the cored bar 22, the position of changing the speed control pattern (the position at which the speed is changed from the speed decrease to the speed increase and the minimum speed position) is changed, and the outer shape of the rubber roll 70 (see FIG. 2B). Evaluation was performed. The position where the speed control pattern is changed corresponds to a specific position M (see FIG. 4) described later.

<Outline evaluation of rubber roll>
As shown in FIG. 3A, the tip position (position of the lower end face 68 in FIG. 1) in the axial direction of the cored bar 22 is A, the center position is E, and the rear end position (upper end face 68 in FIG. 1). F). Further, positions B, C, and D were set as positions between the tip position A and the center position E. Furthermore, the distance between the position A and the rear end position F is L (L is equivalent to the total length of the cored bar 22), the distance between the position A and the position B is L1, the distance between the position A and the position C is L2, and the position A The distance between the position A and the position D is L3, and the distance between the position A and the center position E is L4.

  In this evaluation, the positions B, C, D, and E are represented as L1 / L, L2 / L, L3 / L, and L4 / L as a ratio to the distance L, and the distance L = 1. In this evaluation, based on the result of the preliminary experiment, the position B is set to 0.25, the position C is set to 0.30, the position D is set to 0.48, and the center position E is set to 0.50. The speed control pattern was changed so that the minimum speed was obtained at any one of B, C, D, and E.

(Speed control pattern)
As shown in FIG. 4, a graph G1 of the feeding speed V2 of the cored bar 22 (see FIG. 3A) was set. Specifically, the graph G1 has a speed control pattern α in which the speed decreases from the position A to the specific position M, and the speed from the specific position M to the rear end position, with the position where the feeding speed V2 is the slowest as the specific position M. The curve has an increasing speed control pattern β. Further, in the graph G1, the feeding speed V2 = Vf at the position A, the feeding speed V2 = Vm at the specific position M, the feeding speed V2 = Vr at the rear end position F, and Vm <Vr <Vf. . Note that the distance from the position A to the specific position M is Lm.

  Here, regarding the graph G1, the rubber roll 70 (see FIG. 3C) was manufactured by changing the specific position M = 0.25, 0.30, 0.40, 0.50. And as shown in FIG.3 (C), the distance Lx from the front-end | tip position A of the position Q used as the outer diameter Df in the front-end | tip position A, the maximum outer diameter Dm, and the maximum outer diameter Dm in the rubber roll 70 as a completed body, And the outer diameter Dr at the rear end position F was evaluated.

(Rubber material)
The rubber material G used in this evaluation is epichlorohydrin rubber (trade name: EPION301, company name: Daiso) 100 parts by mass, processing aid (trade name: Tsubaki, company name: Japanese fats and oils) 1 part by mass, carbon black (Product name: 3030B, company name: Mitsubishi Chemical) 12 parts by mass, calcium carbonate (product name: Viscoexcel-30, company name: Shiraishi Kogyo) 40 parts by mass, plasticizer (product name: DB02, company name: Daiso) 3 Rubber containing 6 parts by mass of sulfur, 6 parts by mass of sulfur (trade name: Noxeller DM, company name: Ouchi Shinsei Chemical), and 5 parts by mass of a vulcanization accelerator (trade name: 2 types of zinc oxide, company name: Shodo Chemical) The material was kneaded using a closed kneader and a roll machine to obtain an unvulcanized one. The rubber material G had a Mooney viscosity of 50 according to JISK6300-1 (2001).

(Extrusion condition)
The cored bar 22 used for this evaluation is made of SUS (stainless steel) having L (full length) = 354.5 [mm] and an outer diameter of φ8.0 [mm]. The extruder used is a Mitsuba Seisakusho φ60 [mm], L / D (effective screw length) of 20, the screw rotation speed is 10 [rpm], the die diameter is φ12.5 [mm], extrusion The pressure was 23 [MPa]. The target values of the rubber roll 70 (see FIG. 3C) are: Dm = 12.1 [mm], Df = Dr = 12.0 [mm], crown amount (the outer diameter of the central portion and the outer diameter of both ends) Difference) = 0.10 [mm].

(Process after extrusion)
The unvulcanized rubber material G was extruded with an extruder, and at the same time, the cored bar 22 was continuously passed through the extruder to form the rubber roll. Thereafter, the rubber roll 70 (see FIG. 3 (B)) in which the vulcanized rubber layer of the rubber material G was formed on the cored bar 22 was vulcanized by placing it in a hot air oven at 165 [° C.] for 75 minutes. . Then, the rubber material G at both ends of the vulcanized rubber roll 70 was cut to expose the cored bar 22.

(Measurement of outer diameter of rubber roll)
For measurement of the outer diameter of the rubber roll 70, a light-shielding laser outer diameter measuring device (manufactured by Asaka Riken: ROLL2000) was used.

(Image evaluation)
The obtained rubber roll 70 was attached to an image forming apparatus (manufactured by Fuji Xerox Co., Ltd .: Docu Center-IV C2260, voltage applied to the rubber roll -1000 [V]) as a charging roll, and image evaluation was performed. The image evaluation was carried out by forming a single gray solid image and visually checking the density unevenness of the fixed image. The image evaluation results were evaluated in a two-step evaluation, with ◯ indicating that no density unevenness was visually confirmed, and x indicating that density unevenness was visually confirmed.

Here, the evaluation results are shown in Table 1.

  As shown in Table 1, when the specific position M (see FIG. 4) at which the feeding speed V2 of the cored bar 22 is the minimum speed is 0.30, 0.48 with respect to the total length 1 of the cored bar 22, the image It was confirmed that the evaluation was ○. On the other hand, when the specific position M is 0.25 or 0.50 with respect to the total length 1 of the core metal 22, it was confirmed that the image evaluation was x. From this result, it was confirmed that the specific position M is preferably set within a range of 0.30 or more and 0.48 or less. In the present embodiment, as an example, the specific position M is set at a position of 0.38 with respect to the total length 1 of the cored bar 22. Conditions 1 and 2 are conditions of this embodiment.

Next, the distance from the front end position A of the set center position in the axial direction of the cored bar 22 (the position where the cored bar 22 is equally divided in the axial direction) = 354.5 / 2≈177.3 [mm]. Further, the distance from the tip position A of the position Q (see FIG. 3C) having the maximum outer diameter is Lx. That is, the difference between the distance from the tip position A to the set center position and the distance Lx represents the amount of deviation from the set center position of the position Q in the rubber roll 70 of the finished product. Here, regarding the conditions 1, 2, 3, 4 and the rubber roll 70 of the comparative example, Table 2 shows the deviation amount. In Table 2, a minus value means a deviation amount on the front end side from the set center position, and a plus value means a deviation amount on the rear end side from the set center position.

  From the results of Tables 1 and 2, when the specific position M (see FIG. 4) is set within the range of 0.30 or more and 0.48 or less, the deviation amount [mm] compared to that set outside the range. Was confirmed to be small. Further, when the specific position M was set to 0.50 (set center position), it was confirmed that the maximum outer diameter position of the crown was shifted to the rear end side from the set center position of the cored bar 22.

  On the other hand, from the results of Tables 1 and 2, the conditions 1 and 2 that are “good” in the image evaluation are compared with the conditions 3 and 4 and the comparative example, the position Q in the rubber roll 70 of the finished product (see FIG. 3C) It was confirmed that the amount of deviation from the set center position of That is, by setting the specific position M (see FIG. 4) within a setting range of 0.30 or more and 0.48 or less, not only the image evaluation becomes “good”, but also the deviation amount from the set center position becomes small. Was confirmed.

[Action]
Next, the operation of this embodiment will be described.

  With reference to the flowchart shown in FIG. 5, FIGS. 6 (A), (B), (C), FIGS. 7 (A), (B), and FIGS. 8 (A), (B), (C), rubber rolls A manufacturing procedure of the rubber roll 70 in the manufacturing apparatus 10 will be described. The feeding speed V2 of the cored bar 22 is changed according to the speed control pattern of the graph G1 shown in FIG.

  In step S10, when the rubber roll manufacturing apparatus 10 (see FIG. 1) is activated, the supply motor 30 is driven. Thereby, the screw 28 is rotationally driven, and the unvulcanized rubber material G is extruded into a cylindrical shape at an extrusion speed V1 (an example of the first step). The extrusion speed V1 does not change in subsequent steps. Then, the process proceeds to step S12.

  Subsequently, in step S12, the drive motor 84 is driven. Thereby, the drive roll 54 and the roll pair 50 rotate, and the cored bar 22 starts to be fed into the central portion of the rubber material G at the feeding speed V2 (see FIG. 6A). And when the front-end | tip (lower end) of the metal core 22 arrives at the exit of the mandrel 36, it transfers to step S14. In addition, although illustration is abbreviate | omitted, the front-end | tip (lower end) of the metal core 22 is covered with the rubber material G because the press member 60 moves to a horizontal direction.

  Subsequently, in step S14, the feeding speed V2 of the cored bar 22 is decreased by the speed control pattern α (see FIGS. 4 and 6B). Then, the process proceeds to step S16.

  Subsequently, in step S16, when the specific position M (here, as an example, a position of 0.38 with respect to the total length 1 of the cored bar 22) reaches the junction 48 (that is, the specific position M is the mandrel 36). When it is discharged from the vehicle and reaches the junction 48), the process proceeds to step S18. On the other hand, when the specific position M has not reached the junction 48, step S16 is repeated. In step S16 (an example of the second step), the feeding speed V2 of the cored bar 22 is the slowest and becomes the speed Vm (see FIG. 4).

  Whether or not the specific position M has reached the junction 48 is determined based on the elapsed time from the start of feeding of the cored bar 22 and the speed control pattern. The arrival of the specific position M at the joining portion 48 means that the specific position M of the cored bar 22 reaches the lower end of the mandrel 36.

  Subsequently, in step S18, the feeding speed V2 of the cored bar 22 is increased by the speed control pattern β (see FIGS. 4 and 6C). Then, the process proceeds to step S20.

  Subsequently, in step S20, it is determined whether or not the rubber material G has been fed to the rear end of the core metal 22. And when it is sent to the rubber material G to the rear end of the core metal 22, it transfers to step S22. On the other hand, when the rubber material G has not been fed to the rear end of the core bar 22, step S20 is repeated. The determination as to whether or not the core bar 22 has been fed to the rear end is determined based on the elapsed time from the start of feeding of the core bar 22, the speed control pattern, and the total length of the core bar 22.

  Subsequently, in step S22, the rubber roll portion 56 (core metal 22 and rubber material G) is taken out by the take-out portion 16 (see FIGS. 7A and 7B). At this time, the take-out member 64 takes out the rubber roll portion 56 at a take-out speed V3 downward (an example of a third step). Then, the process proceeds to step S24. In the middle of taking out the rubber roll portion 56, the tip (end surface 68) of the next (rear) cored bar 22 is stopped at the lower end of the mandrel 36. At this time, the feeding speed V2 of the next cored bar 22 is zero.

  Subsequently, in step S24, it is determined whether or not to continue feeding the next cored bar 22 to the rubber material G. This is determined, for example, based on whether or not the number of rubber roll portions 56 taken out has reached the set number of rubber rolls 70 to be manufactured. When the next cored bar 22 is not fed (the set number of manufactured cores is reached), the process proceeds to step S26. On the other hand, when feeding the next cored bar 22 (not reaching the set production number), the process proceeds to step S14.

  Subsequently, in step S26, the supply motor 30 and the drive motor 84 are stopped, and the feeding of the cored bar 22 to the rubber material G is stopped. When the core bar 22 is continuously fed into the rubber material G, as shown in FIGS. 8A, 8B, and 8C, the rubber roll portion 56 and the central portion of the rubber material G are hollow. The hollow portions 58 are discharged alternately. And when the hollow part 58 moves to the opposing position of the press member 60, each press member 60 is moved to the direction which mutually approaches, and the rubber material G of the hollow part 58 is inward by the protrusion part 62 of each press member 60. Pressed. Thereby, the end surface 68 of the front core metal 22 and the end surface 68 of the rear core metal 22 are covered with the rubber material G of the hollow portion 58.

  Subsequently, when the pressing members 60 are moved in directions away from each other, the rubber roll 70 in which the cored bar 22 has a bag-like shape (both ends of the cored bar 22 are covered with the rubber material G) is formed. Each take-out member 64 moves downward while gripping the separated rubber roll 70, and then moves to a standby position for gripping the next rubber roll portion 56. Then, the obtained rubber roll 70 is subjected to the vulcanization process and the processing (cutting) process described above.

  Here, when the outer diameter of the rubber roll 70 in which the specific position M is set to a position of 0.38 with respect to the total length 1 of the core metal 22 is measured by the method described above, a profile G2 shown in FIG. 9 is obtained. It was. In FIG. 9, the horizontal axis is the distance [mm] from the tip of the cored bar 22, and the vertical axis is the thickness of the rubber layer of the rubber material G (thickness with reference to the outer peripheral surface of the cored bar 22) [mm]. It has become.

  In the profile G2, the position where the maximum outer diameter (crown-shaped apex position) is 180 [mm] from the tip, and is substantially at the center position with respect to the total length of the cored bar 22 = 354.5 [mm]. It was confirmed that there was.

  As described above, in the example of the rubber roll manufacturing apparatus, the rubber roll manufacturing method, and the rubber roll manufacturing program of the present embodiment, when the cored bar 22 is fed into the cylindrical rubber material G, the core from the tip to the specific position M is The feeding speed V2 of the gold 22 is reduced. From the specific position M to the rear end, the feeding speed V2 of the cored bar 22 is increased. As a result, a crown-shaped rubber roll 70 whose center in the axial direction is thicker than both ends is formed.

  In the present embodiment, the specific position M (the position at which the feeding speed V2 of the cored bar 22 is the lowest speed) is set to the front end side with respect to the central position in the axial direction (feeding direction) of the cored bar 22. For this reason, even if the moving speed of the rubber material G located far from the core metal 22 in the radial direction of the core metal 22 is slower than the moving speed of the rubber material G located near the core metal 22, the core metal 22 A maximum outer diameter portion is formed at the central portion in the axial direction. Thereby, in this embodiment, it is suppressed that the position where a rubber roll becomes the largest outer diameter in the axial direction of the cored bar 22 is shifted from the axial center position of the cored bar 22.

  Furthermore, in the present embodiment, both end portions in the axial direction of the cored bar 22 are sealed with the rubber material G, and then the rubber roll portion 56 is taken out. Here, as a comparative example, when both ends in the axial direction of the core metal 22 are not covered with the rubber material G, when the rubber between the front core metal 22 and the rear core metal 22 is cut, The rubber material G expands in a trumpet shape at the end of the cored bar 22 due to contraction.

  On the other hand, in the present embodiment, both ends in the axial direction of the cored bar 22 are covered (sealed) with the rubber material G, and after the vulcanization treatment is performed, the rubber material G at both ends is cut. At this time, since the rubber material G at both ends to be cut is after vulcanization, the amount of shrinkage due to cutting is smaller than in the comparative example. Thereby, the error with respect to the set value of the outer diameter of the both ends in the axial direction of the rubber roll 70 is reduced.

  In the present embodiment, the setting range of the specific position M is set including the amount of covering both ends in the axial direction of the cored bar 22 with the rubber material G. For this reason, even when both ends of the cored bar 22 are covered with the rubber material G, it is possible to suppress the position where the maximum outer diameter is shifted in the axial direction from the center position of the cored bar 22.

  In addition, in the present embodiment, the specific position M is set within a setting range on the tip side with respect to the axial center position of the cored bar 22. Thereby, even if the viscosity of the rubber material constituting the rubber material G is higher than that of epichlorohydrin rubber or the thickness of the rubber layer is thicker than that of the rubber roll 70, the position where the maximum outer diameter is reached is the core. It is formed at the center of the gold 22.

  In the present embodiment, as described above, the position where the maximum outer diameter in the axial direction of the cored bar 22 is suppressed from being shifted from the center position of the cored bar 22, so that the specific position M is the configuration of the center position. Compared with, the productivity of crown-shaped rubber rolls is increased.

  In addition, this invention is not limited to said embodiment.

  The means for extruding the rubber material G is not limited to a screw shape, and may be a piston shape. Further, the feeding means for the cored bar 22 is not limited to the roll pair, and may be a moving member having a gripping portion. Furthermore, the take-out means of the rubber roll unit 56 is not limited to the one that grips and moves the rubber roll unit 56, but may be moved by a roll pair.

  The specific position M may be selected from a setting range of 0.30 or more and 0.48 or less with respect to the total length 1 of the cored bar 22, and is not limited to 0.38 described in the embodiment.

  In the rubber roll manufacturing apparatus 10, the rubber roll 70 is separated by the hollow portion 58 by the pressing portion 14, but after the rubber material of the hollow portion 58 is pressed inward by the pressing portion 14, another cutting member (cutter) You may comprise so that the rubber roll 70 may be isolate | separated by.

  Although the rubber material G illustrated what used epichlorohydrin rubber, it is not restricted to this, You may use another rubber material. Further, in the rubber roll 70, the entire end surface 68 of the cored bar 22 is covered with a rubber material G in the hollow part 58 in the form of a bag, but this is not limiting, and at least the peripheral part of the end surface 68 of the cored bar 22 is hollow. What is necessary is just to be covered with the rubber material G of the part 58. FIG.

  The rubber roll 70 (completed body) of the present embodiment is used in an image forming apparatus such as a copying machine or a printer. However, the use is not limited to a charging roll, but is used for a recording medium conveyance roll, a development roll, a transfer roll, and the like. Also good.

10 Rubber roll manufacturing equipment,
16 Extraction part (an example of extraction means),
20 Extrusion part (an example of an extrusion means),
22 Core,
24 sending part (an example of sending means),
56 Rubber roll part,
80 control unit (an example of control means),
G rubber material,
M Specific position

Claims (4)

A first step of extruding an unvulcanized rubber material into a cylindrical shape;
A step of feeding a cored bar to the rubber material, wherein the length of the cored bar in the axial direction is 1 and the length from the tip position in the feeding direction of the cored bar is in the range of 0.30 to 0.48 A second step of feeding the core metal into the rubber material while decreasing and increasing the feed speed so that the feed speed of the core metal is the slowest at a specific position in
A third step of taking out a rubber roll portion whose outer peripheral surface is covered with the rubber material;
A rubber roll manufacturing method comprising:   The rubber roll manufacturing method according to claim 1, wherein both ends of the core metal are sealed with the rubber material. Extrusion means for extruding unvulcanized rubber material into a cylindrical shape;
Feeding means for feeding a cored bar to the center of the rubber material extruded by the pushing means;
An extraction means for taking out a rubber roll portion whose outer peripheral surface is covered with the rubber material;
The length of the cored bar in the axial direction is set to 1, and the feeding speed of the cored bar is the highest at a specific position within a range of 0.30 or more and 0.48 or less in the feeding direction of the cored bar. Control means for controlling the decrease and increase of the feeding speed of the cored bar by the feeding means so as to be slow;
A rubber roll manufacturing apparatus having: The rubber roll manufacturing program for functioning a computer as the said control means which comprises the rubber roll manufacturing apparatus of Claim 3.