JP6724461B2 - Rubber roll manufacturing equipment - Google Patents

Description

The present invention relates to a rubber roll manufacturing apparatus for manufacturing a rubber roll.

Patent Document 1 discloses a method for manufacturing a rubber roll in which the outer circumference of a core metal is coated with a rubber material by a rubber extruder having a crosshead. The crosshead is composed of a die and a mandrel, and the rubber material is extruded along a spiral groove provided on the inner wall of the die toward the exit direction, and a spiral groove provided on the outer wall of the mandrel constituting the crosshead toward the exit direction. Along which the rubber material is extruded.

Patent Document 2 discloses an extruder equipped with a crosshead die for manufacturing a conductive rubber roll by coating a shaft with a rubber composition. The crosshead die has two strips of a manifold portion that spreads a rubber composition that has been introduced from an inlet port in two directions, and the rubber composition that has passed through the manifold portion is spirally diffused in the circumferential direction of the crosshead die. And the spiral part of the strip. The inner peripheral surface of the die and the outer peripheral surface of the mandrel have a grounding surface formed by a tapered surface or a cylindrical surface for positioning. The gap between the die and the grounding surface of the mandrel is 0.01 mm or less, and a flow groove in which the rubber composition flows from the inflow port to the position where the rubber compositions spread in two lines meet at the spiral part is arranged on the grounding surface. ing. The portion of the rubber composition that is upstream of the flow is the ground surface of the die and mandrel.

The crosshead die of Patent Document 3 includes an outer die having an outer die hole and a supply port, a mandrel arranged in the outer die hole and having a core metal guide hole and a manifold, and a lower end of the core metal guide hole in the outer die hole. And a die having a die hole arranged below the opening. The cross-sectional area of the expanded flow path in the cutting plane perpendicular to each of the flow direction along the manifold and the flow direction along the axial direction is the extruded cross-sectional area obtained by subtracting the cross-sectional area of the core from the cross-sectional area of the die port. 4.1 times or more and 6.9 times or less. The length of the developing part flow path is 0.5 times or more and 1 time or less than the diameter of the outer die hole at the upper end of the supply port.

JP, 2008-094050, A JP, 2009-034915, A JP, 2011-230485, A

It is an object of the present invention to provide a rubber roll manufacturing apparatus capable of suppressing variation in the shape of the rubber roll in the circumferential direction, as compared with the case where a flow path forming portion having no convex surface is used.

The rubber roll manufacturing apparatus according to the first aspect is provided with a tubular discharge part for discharging unvulcanized rubber charged from a charging port formed in a side part through a discharging port formed at a tip, and an inside of the discharging part. And a flow passage forming portion provided with a reference surface that forms a flow passage of the rubber between the inner peripheral surface of the discharge portion and the inner peripheral surface of the discharge portion, and faces the input port in the axial direction of the discharge portion. When the position of the reference surface is 0°, convex surfaces are provided in the 0°±10° range, the 90°±10° range, and the 270°±10° range of the reference surface, and When the distance to the inner peripheral surface is D, the distance from each convex surface to the inner peripheral surface is 0.5D to 0.9D.

In the rubber roll manufacturing apparatus according to the second aspect, the groove extending from the 0° position to the 180° position of the reference surface is formed in the axial direction from the respective convex surfaces to the charging port side, and from the bottom of the groove to the inner side. The separation distance to the peripheral surface is within the range of 1.1D to 1.5D.

In the rubber roll manufacturing apparatus according to the third aspect, the flow path forming portion includes a base end portion having the reference surface, and a rotationally symmetrical tip end portion extending from the base end portion toward the tip end side. When the length of the base end portion in the axial direction is L1 and the length of the tip end portion is L2, L1/L2 is 3/7 to 5/5.

A rubber roll manufacturing apparatus according to a fourth aspect is provided with a supply unit that supplies the rubber to the discharge unit, and the discharge amount is V when the volume of the rubber supplied to the discharge unit by the supply unit is V. The volume of all the rubber passages formed in the section is 5V to 10V.

The rubber roll manufacturing apparatus according to the first aspect can improve the surface shape of the rubber roll as compared with the case where the flow path forming portion having no convex surface is used.

The rubber roll manufacturing apparatus according to the second aspect can improve the surface shape of the rubber roll as compared with the case where the flow path forming portion having no groove is used.

In the rubber roll manufacturing apparatus according to the third aspect, compared to the case where the flow path forming portion in which (the length L1 of the base end portion)/(the length L2 of the tip end portion) is not 3/7 to 5/5 is used. Therefore, the surface shape of the rubber roll can be improved.

In the rubber roll manufacturing apparatus according to the fourth aspect, when the volume of the rubber supplied per minute is V, the surface of the rubber roll is compared to the case where the volume of all the rubber passages in the discharge part is not 5 V to 10 V The shape can be improved.

It is a block diagram which showed the manufacturing apparatus of the rubber roll which concerns on embodiment. It is a perspective view showing a mandrel as an example of a channel formation part of the embodiment. It is a front view showing a mandrel as an example of a channel formation part of the embodiment. It is a right side view showing a mandrel as an example of a channel formation part of the embodiment. It is a rear view which shows the mandrel as an example of the flow path formation part of the same embodiment. FIG. 5 is a sectional view taken along the line AA of FIG. 4. It is a figure which shows the table of a test result.

A rubber roll manufacturing apparatus 10 according to an embodiment of the present invention will be described with reference to FIG. The arrow H shown in the drawing indicates the vertical direction of the apparatus (vertical direction), and the arrow W indicates the width direction of the apparatus (horizontal direction).

(overall structure)
A rubber roll (not shown) manufactured by the rubber roll manufacturing apparatus 10 is used, for example, as a charging roll that contacts a photosensitive drum of an electrophotographic image forming apparatus and is driven to rotate to charge the photosensitive drum. In order to suppress variations in charging of the photoconductor drum, the rubber roll is required to have a predetermined shape accuracy.

The rubber roll manufacturing apparatus 10 includes an extruder 12 including a so-called crosshead die, a separator 14 arranged below the extruder 12, and a drawer 16 arranged below the separator 14. I have it. Further, the rubber roll manufacturing apparatus 10 includes a cutting machine (not shown).

[Extruder]
The extruder 12 includes a supply unit 18 that supplies unvulcanized rubber, an extrusion unit 20 that extrudes the rubber that is supplied from the supply unit 18 into a cylindrical shape, and a central portion of the rubber that is extruded into a cylindrical shape from the extrusion unit 20. A core metal transport unit 24 for supplying the core metal 22 is provided.

[Supply section]
The supply unit 18 includes a screw 28 arranged inside the cylindrical main body 26, a heater (not shown) for heating rubber in the main body 26, and a screw 28 arranged on the right side of the main body 26 in the drawing. And a drive motor 30 for rotating the motor. Further, a material charging port 32 for charging the rubber 100 is arranged on the drive motor 30 side of the main body 26.

In this configuration, the rubber 100 charged from the material charging port 32 is kneaded by the screw 28 inside the main body 26 and is fed toward the extruding portion 20 as an example of the discharging portion.

As the rubber 100, it is possible to use, for example, one having 80 parts by mass or more of epichlorohydrin rubber in all the polymers and blended with 30 to 60 parts by mass of an inorganic filler such as carbon or calcium carbonate.

[Extrusion section]
The pushing unit 20 is configured to include a cylindrical case 34 connected to the supply unit 18, and a cylindrical holding member 42 provided inside the case 34. An input port 102 into which the rubber 100 supplied from the supply unit 18 is input is formed on a side portion of the case 34. The ejection head 38 is held at the lower end of the holding member 42, and the ejection head 38 is held by the case 34 via the holding member 42. The discharge head 38 is formed with a discharge port 104 for discharging the rubber 100 charged in the extrusion unit 20 downward.

A mandrel 36, which is an example of a cylindrical flow path forming portion, is inserted into a holding member 42 in the case 34 of the pushing-out portion 20 and is supported. The mandrel 36 holds the case 34 through the holding member 42. Held in. A top member 106 for fixing the mandrel 36 is provided on the upper part of the case 34, and the rubber 100 flows annularly between the outer peripheral surface of the mandrel 36 and the inner peripheral surface 42A of the holding member 42. An annular flow path 44 is formed.

Explaining the annular flow channel 44, when the volume of the rubber 100 supplied to the extrusion unit 20 by the supply unit 18 per minute is V, the annular flow channel 44 of the rubber 100 formed in the extrusion unit 20 is configured. The volume of all the flow paths is set to 5V to 10V. Each flow path will be described in detail in the description of the mandrel 36.

[Mandrel]
At the center of the mandrel 36 is formed a passage hole 46 into which the cored bar 22 is inserted and passes. Further, the lower part of the mandrel 36 has a tapered shape toward the tip located on the discharge port 104 side in the set state attached to the extrusion part 20. An area below the tip of the mandrel 36 is a merging area 48 where the core metal 22 supplied from the passage hole 46 and the rubber 100 supplied from the annular flow path 44 merge. That is, the rubber 100 is extruded in a cylindrical shape toward the confluence region 48, and the core metal 22 is fed to the central portion of the rubber 100 extruded in the cylindrical shape.

As shown in FIGS. 1 to 6, the mandrel 36 includes a disk-shaped base portion 110 supported in a state of being surrounded by a case 34, a base end portion 112 extending from the base portion 110 toward a tip side, and a base portion. A tip portion 114 extending from the end portion 112 to the tip side is included.

A bottomed circular hole 110A is formed on a side surface of the base 110 at a predetermined position, and the positioning pin 116 can be inserted into the circular hole 110A in a protruding state as shown in FIG. Is configured. By setting the positioning pin 116 in alignment with a positioning groove (not shown) provided in the pushing portion 20, the mounting position of the mandrel 36 with respect to the pushing portion 20 in the circumferential direction is determined.

The base end portion 112 is formed in a cylindrical shape having a smaller diameter than the base portion 110 and a passage hole 46 (see FIG. 6) penetrating the center portion thereof. As shown in, the reference surface 120 that forms the flow path of the rubber 100 (the annular flow path 44) is formed between the inner peripheral surface 42A of the holding member 42.

As shown in FIGS. 2 and 4 in the set state of the mandrel 36, when the position in the circumferential direction S of the reference surface 120 facing the input port 102 in the axial direction J of the extrusion part 20 is 0°, 0 Grooves 122 extending from the ° position to the 180° position are formed on both sides in the circumferential direction S. A circular hole 110A is provided at this 180° position.

The groove 122 is inclined from the base end side to the tip end side of the mandrel 36 as it goes from the 0° position to the 180° position, and the tips of both grooves 122 are as shown in FIGS. 2 and 5. , 180° position. On the groove bottom 122A of both grooves 122, as shown in FIG. 3, a mountain-shaped protruding ridge 124 is formed in the groove width direction at the 0° position. As a result, the rubber 100 input from the input port 102 can be distributed and flown into the left and right grooves 122 with the ridge 124 as a boundary.

As shown in FIG. 4, each groove 122 has a separation distance K1 from the groove bottom 122A to the inner peripheral surface 42A of 1 when the separation distance from the reference surface 120 to the inner peripheral surface 42A of the holding member 42 is D. It is set to fall within the range of 1D to 1.5D.

A thick portion 125 protruding from the reference surface 120 is formed between the groove 122 and the base 110. Accordingly, the mandrel 36 is inserted into the holding member 42 of the pushing portion 20, and the thick portion 125 is fitted to the inner peripheral surface 42A of the holding member 42 while being in close contact with the holding member 42.

In the region of the reference surface 120 located on the tip side of the groove 122, as shown in FIG. 3, an inlet-side convex surface 126 as an example of a convex surface is formed within at least 0°±10°. The inlet-side convex surface 126 projects in a triangular shape having an apex on the tip side of the mandrel 36 when viewed from the 0° direction, and as shown in FIG. 4, the separation distance K2 from the inlet-side convex surface 126 to the inner peripheral surface 42A. Is set to be 0.5D to 0.9D.

Further, in the region of the reference surface 120 located on the tip side of the groove 122, as shown in FIGS. 3 and 4, at least within a range of 90°±10° and within a range of at least 270°±10°. A side convex surface 128 is formed as an example of a convex surface. The side convex surface 128 is formed in a quadrangular shape when viewed from the 90° direction and the 270° direction, one side thereof is arranged along the groove 122, and the corner portions facing each other are located on the distal side and the proximal side. It is arranged to face. Then, as shown in FIG. 5, the separation distance K3 from the side-side convex surface 128 to the inner peripheral surface 42A is set to be 0.5D to 0.9D. A reference surface 120 exists between the inlet-side convex surface 126 and the side-side convex surface 128 and on the tip side of the inlet-side convex surface 126 and the side-side convex surface 128.

Thereby, between the base end portion 112 of the mandrel 36 and the inner peripheral surface 42A of the holding member 42 of the pushing portion 20, as shown in FIG. 4, a flow path having a separation distance K1 along the groove 122, A flow path having a separation distance K2 is formed along the inlet-side convex surface 126. Further, between the base end portion 112 and the inner peripheral surface 42A, as shown in FIGS. 4 and 5, the flow path having the separation distance K3 along the side convex surface 128 and the separation along the reference surface 120 are formed. A flow path having a distance D is formed.

As shown in FIGS. 2 and 3, the distal end portion 114 has a smaller diameter than the proximal end portion 112 and is formed in a cylindrical shape with a passage hole 46 (see FIG. 6) penetrating through the central portion thereof, and is rotated around the axis. It is formed in a symmetrical shape. The distal end portion 114 is provided on the proximal end portion 112 side and is reduced in diameter toward the distal end side, a proximal end reduced diameter portion 114A, a cylindrical portion 114B extending from the proximal end side reduced diameter portion 114A toward the distal end side, and a cylindrical portion 114B. It is configured to include a tip-side reduced diameter portion 114C that reduces its diameter toward the tip side.

As shown in FIG. 3, the axial length of the distal end portion 114 is such that when the axial length of the proximal end portion 112 is L1 and the distal end portion 114 is L2, The ratio L1:L2 is set within the range of 3:7 to 5:5. That is, (the length L1 of the base end portion 112)/(the length L2 of the tip end portion 114) is set to be 3/7 to 5/5.

[Core bar transport section]
As shown in FIG. 1, the cored bar transport unit 24 includes a pair of rollers 50 arranged above the mandrel 36. A plurality of pairs (for example, three pairs) of roller pairs 50 are provided, and one roller (left side in the drawing) of each roller pair 50 is connected to a driving roller 54 via a belt 52. When the drive roller 54 is driven, the core metal 22 sandwiched by the roller pairs 50 is conveyed toward the passage hole 46 of the mandrel 36. The mandrel 22 has a predetermined length, and the rear mandrel 22 sent by the roller pair 50 pushes the leading mandrel 22 present in the passage hole 46 of the mandrel 36 to thereby form a plurality of mandrels. 22 passes through the passage hole 46 in sequence.

In this structure, the cored bar transport unit 24 transports the cored bar 22 downward in the vertical direction, and the drive of the drive roller 54 is temporarily stopped when the tip of the leading cored bar 22 reaches the tip of the mandrel 36. It is about to be done. Then, the rubber 100 is extruded into a cylindrical shape in the merging area 48, and the cored bar 22 is sequentially fed into the central portion of the rubber 100 at intervals. As a result, the rubber roll portion 56 in which the outer peripheral surface of the cored bar 22 is covered with the rubber 100 and the hollow portion 58 in which the inside of the rubber 100 is hollow between the cored bar 22 are alternately discharged. It is supposed to be discharged from. A primer is applied to the outer peripheral surface of the cored bar 22 in advance in order to enhance the adhesiveness with the rubber 100.

〔Separator〕
The separator 14 includes a pair of semi-cylindrical separation members 60. The pair of separating members 60 are arranged so as to face each other so as to sandwich the rubber roll portion 56 discharged from the extruder 12. Each of the separation members 60 is formed with a protrusion 62 that protrudes toward the center. Each separating member 60 is movable in the left-right direction in the drawing by a drive mechanism (not shown) to separate the front rubber roll portion 56 and the rear rubber roll portion 56. As a result, a rubber roll body (not shown) in which the leading core metal 22 has a bag-like binding shape is formed.

[Drawer]
The drawer 16 has a pair of semi-cylindrical gripping members 64. The pair of gripping members 64 are arranged to face each other so as to sandwich the rubber roll portion 56 discharged from the extruder 12. Each grip 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 gripping member 64 is movable in the left-right direction and the vertical direction by a drive mechanism (not shown).

(Action)
The operation of the present embodiment having the above configuration will be described. An inlet side convex surface 126 is formed on the reference surface 120 of the mandrel 36 held by the extruding section 20 in the range of 0°±10° on the side of the charging port 102 of the rubber 100. When the distance from the reference surface 120 to the inner peripheral surface 42A of the holding member 42 is D, the distance from the inlet side convex surface 126 to the inner peripheral surface 42A is set to be 0.5D to 0.9D. Has been done.

As a result, the flow passage width from the inlet side convex surface 126 to the inner peripheral surface 42A is narrower than the flow passage width from the reference surface 120 to the inner peripheral surface 42A, and the rubber 100 injected from the charging opening 102 is provided below. Direct movement to the discharged outlet 104 is suppressed, and detour to the side is promoted.

Further, on the reference surface 120 of the mandrel 36, side-side convex surfaces 128 are formed in the range of 90°±10° and the range of 270°±10° of the reference surface 120. The separation distance to 42A is set to be 0.5D to 0.9D.

As a result, the channel width from the side-side convex surface 128 to the inner peripheral surface 42A is narrower than the channel width from the reference surface 120 to the inner peripheral surface 42A. Therefore, the rubber 100 diverted in the lateral direction at the inlet side convex surface 126 is suppressed from moving to the lower outlet port 104 by the side side convex surface 128, and the movement to the opposite side (180° side) to the input port 102 is promoted. To be done.

As described above, as compared with the case where the mandrel 36 having no convex surfaces 126 and 128 is used, the flow rate of the rubber 100 in the circumferential direction becomes uniform, and the thickness of the manufactured rubber roll in the circumferential direction becomes uniform. It is possible to reduce the variation in circularity.

Further, when the mandrel 36 having no convex surfaces 126 and 128 is used, the rubber 100 passing through the opposite side (180° side) of the charging port 102 has a large pressure loss and the flow tends to stagnant. In this case, a weld line may be formed or minute unevenness may be formed on the surface by the scorch of the rubber 100.

However, in this embodiment, since the stagnation of the rubber 100 can be suppressed even on the side opposite to the charging port 102, the formation of weld lines and minute irregularities can be suppressed, and the surface shape can be improved. Along with this, there is no need to perform a polishing operation on the rubber roll after molding, so that manufacturing costs such as labor costs and material costs can be significantly reduced.

Further, in this embodiment, the groove 122 extending from the 0° position to the 180° position of the reference surface 120 is formed closer to the inlet 102 than the convex surfaces 126 and 128, and extends from the groove bottom 122A of the groove 122 to the inner peripheral surface 42A. The separation distance K1 is set to be 1.1D to 1.5D.

As a result, the flow channel width from the groove bottom 122A of the groove 122 to the inner peripheral surface 42A is wider than the flow channel width from the reference surface 120 to the inner peripheral surface 42A, and the rubber 100 charged from the charging port 102 is discharged. It is possible to promote the movement to the side opposite to the input port 102. Therefore, the surface shape of the rubber roll can be improved as compared with the case where the mandrel 36 having no groove 122 is used.

Further, in the mandrel 36, when the length of the base end portion 112 where the convex surfaces 126 and 128 and the groove 122 are formed is L1 and the length of the tip end portion 114 is L2, L1/L2 is 3/7 to 5 It is set to be /5.

Therefore, the merging portion of the rubber 100 flowing from both sides of the mandrel 36 to the opposite side of the charging port 102 via the convex surfaces 126 and 128 and the groove 122 of the basal portion 112 is the merging portion. It can be closely joined while passing through the smaller diameter tip 114.

As a result, the mandrel in which (the length L1 of the base end portion 112)/(the length L2 of the tip end portion 114) is outside the range of 3/7 to 5/5 and the length L2 of the tip end portion 114 is less than the lower limit value. The formation of weld lines can be suppressed and the surface shape of the rubber roll can be improved as compared with the case of using.
On the other hand, if the length L2 of the tip 114 exceeds the upper limit value, the vulcanization of the rubber 100 will be faster than the design value. Therefore, (length L1 of the base 112)/(length L2 of the tip 114) Is preferably in the range of 3/7 to 5/5.

When the volume of the rubber 100 supplied to the extrusion unit 20 by the supply unit 18 per minute is V, the volume of the entire passage of the rubber 100 formed in the extrusion unit 20 is set to be 5V to 10V. Has been done.

Therefore, as compared with the case where the volume of all the passages of the rubber 100 is not 5V to 10V, the replacement cycle of the rubber 100 in the extruding section 20 becomes appropriate, and the rubber 100 starts the initial vulcanization during the process. It is possible to suppress the formation of minute irregularities due to the scorch. Thereby, the surface shape of the rubber roll can be improved.

<Test>
In order to prove the effect of this embodiment, Example 1 to Example 10 and Comparative Example 1 to Comparative Example 8 were carried out according to each condition of the table shown in FIG. 7.

In each example and each comparative example, the separation distance K2 from the inlet-side convex surface 126 of the mandrel 36 to the inner peripheral surface 42A, the separation distance K3 from the side-side convex surface 128 to the inner peripheral surface 42A, and the groove bottom 122A of the groove 122. The distance K1 from the inner peripheral surface 42A to the inner peripheral surface 42A is the value shown in the table. Further, in each of the examples and the comparative examples, the ratio L1:L2 of the length L1 of the base end portion 112 and the length L2 of the tip end portion 114 of the mandrel 36, and the total flow of the rubber 100 between the extruding portion 20 and the mandrel 36. The volume of the passage is the value shown in the table.

(Test conditions)
-Rubber 100 parts by mass (epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber Hydrin T3106: manufactured by Zeon Corporation)
Conductive agent (carbon black Asahi Thermal: Asahi Carbon Co., Ltd.) 20 parts by mass Conductive agent (Ketjen Black EC: manufactured by Lion Co., Ltd.) 2 parts by mass Ion conductive agent 1 part by mass (benzyltrimethylammonium chloride, trade name "BTEAC" (Lion Akzo)
・Vulcanizing agent 1.5 parts by mass (organic sulfur 4,4'-dithiodimorpholine Barnock R: manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
・Vulcanization accelerator 1.5 parts by mass (di-2-benzothiazolyl disulfide Noxeller DM-P: manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
・Vulcanization accelerator 1.8 parts by mass (Tetraethyl thiuram disulfide Noxera TET-G: manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
・Vulcanization accelerating aid (zinc oxide, zinc oxide type 1: manufactured by Shodo Chemical Co., Ltd.) 3 parts by mass, stearic acid 1.0 part by mass, heavy calcium carbonate 40 parts by mass

"Rubber roll manufacturing conditions"
A rubber roll was manufactured using a "60 mm uniaxial bent rubber extruder" manufactured by Mitsuba Seisakusho. A core metal made of SUS303 having a diameter of 8 mm and a length of 330 mm is prepared, rubber is extruded into a cylindrical shape from the extruding part of the rubber roll manufacturing apparatus having the following settings, and the core metal is supplied to the center of the extruded rubber to form a core A cylindrical rubber was coated on the outer peripheral surface of the gold. Then, the unvulcanized rubber roll having the outer peripheral surface of the cored bar covered with rubber was vulcanized at 160° C. for 60 minutes in an air heating furnace.
-Cylindrical body (cylinder): length L = 1200 mm, inner diameter ID = 60 mm, screw rotation = 16 rpm
・Breaker plate: Φ OD 1.3mm, 60 holes

<Crosshead extrusion conditions>
Core bar shaft: total length 350 mm, outer diameter φ8.0 mm Extruder: Mitsuba Seisakusho φ60 mm, L/ID20
Screw rotation speed: 10 rpm Die diameter: φ12.5 Extrusion pressure: 23 MPa

"Evaluation method"
-Roundness: Roundness was calculated using Rondocom at a pitch of 30 mm. The smaller the number, the better.
-Small irregularities: If any irregularities having a height of 30 μm and a width of 50 μm or more are visually inspected, it is judged as NG. 100 molding under each condition.
◯: NG is 2/100 or less Δ: 2/100 to 5/100 ×: 5/100 or more ・Image quality evaluation Using the rubber roll manufactured in each example as a charging roll, an image forming apparatus "DocuCenter-V C5580: manufactured by Fuji Xerox Co., Ltd." I put it on. Using this image forming apparatus, 10 half-tone images having an image density of 40% were output on A4 paper in an environment of a temperature of 10° C. and a humidity of 15% RH. Then, the image quality of the finally output image was evaluated.
○: No defects such as density unevenness △: Minor density unevenness occurred ×: Density unevenness that cannot be actually used

As shown in FIG. 7, it was confirmed that Examples 1 to 16 are superior to Comparative Examples 1 and 2 in all of the roundness, the fine irregularities, and the density unevenness.

10 Rubber Roll Manufacturing Equipment 18 Supplying Section 20 Extruding Section (Example of Discharging Section)
36 Mandrel (an example of flow path forming part)
42A Inner peripheral surface 44 Annular flow path 100 Rubber 102 Inlet 104 Outlet 112 Base end 114 Tip portion 120 Reference surface 122 Groove 122A Groove bottom 126 Entrance side convex surface 128 Side convex surface J Axial direction

Claims (3)

A cylindrical discharge part for discharging unvulcanized rubber charged from a charging port formed on the side from a discharging port formed on the tip,
A flow passage forming portion provided in the discharge portion and forming a flow passage of the rubber between the discharge portion and the inner peripheral surface thereof , the flow passage forming portion having a cylindrical reference surface,
When the position of the reference surface facing the input port in the axial direction of the discharge portion is 0°, the reference surface has a 0°±10° range, a 90°±10° range, and a 270°±10° range. A convex surface that partially protrudes from the reference surface is provided in the range, and when the distance from the reference surface to the inner peripheral surface is D, the distance from each convex surface to the inner peripheral surface is 0.5D to 0.9D,
Grooves that extend from the 0° position to the 180° position of the reference surface and are concave with respect to the reference surface are formed in the axial direction from the respective convex surfaces to the insertion port side, and from the bottom of the groove to the inner side. An apparatus for manufacturing a rubber roll, wherein a separation distance to the peripheral surface is within a range of 1.1D to 1.5D . The flow path forming portion includes a base end portion having the reference surface, and a rotationally symmetrical distal end portion extending toward the distal end side from the base end portion,
The rubber roll manufacturing apparatus according to claim 1, wherein L1/L2 is 3/7 to 5/5 when the length of the base end portion in the axial direction is L1 and the length of the tip end portion is L2. A supply unit for supplying the rubber to the discharge unit is provided, and assuming that the volume of the rubber supplied to the discharge unit by the supply unit for one minute is V, all the flow paths of the rubber formed in the discharge unit are The apparatus for manufacturing a rubber roll according to claim 1 or 2, wherein the volume is 5V to 10V.