JP2012040577A - Method for manufacturing cylindrical shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a cylindrical shaft having a stable shape.SOLUTION: The method for manufacturing a cylindrical shaft includes a step for processing a cylinder to form the cylindrical shaft curved in a constant direction in an axial direction by performing a press bending of a metallic sheet that is formed to have a length in a bending direction set to a predetermined length shorter than the cylinder perimeter of a press die, such that both ends in the bending direction come close to or are brought into contact with each other so that the metallic sheet is formed in a cylindrical shape. The predetermined length is defined within a certain range based on the length obtained by subtracting the stretch amount in the bending direction in the press bending of the metallic sheet from the cylinder perimeter of the press die.

Description

    The present invention relates to a method for manufacturing a cylindrical shaft.

2. Description of the Related Art Conventionally, a printing apparatus that prints information on a sheet-like recording medium has been used, and this printing apparatus is provided with a conveying apparatus that conveys the recording medium.
The conveyance device includes a conveyance roller that conveys a recording medium by rotating, and a driven roller that is urged and brought into contact with the conveyance roller, and the recording medium is sandwiched between the conveyance roller and the driven roller. And is designed to be transported. A solid bar-like member is generally used for the transport roller. On the other hand, solid materials have the problem of increasing weight and cost.

Patent Document 1 describes a technique of bending a metal plate into a cylindrical shape.
In the cylindrical shaft described in Patent Document 1, when the metal plate is bent and formed into a cylindrical shape, the end faces of the metal plate are brought into contact with each other. For this reason, a joint (seam) is formed between the pair of end faces of the metal plate over the entire length of the cylindrical shaft.

JP 2006-289596 A

However, the present inventors have found that in the above configuration, the shape of the cylindrical shaft may change over time. This shape change is considered to be the effect of, for example, stress remaining when the cylindrical shaft is formed by bending, and the residual stress is relaxed over time.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method for manufacturing a cylindrical shaft having a stable shape.

In the method for manufacturing a cylindrical shaft according to the present invention, a metal plate formed in a predetermined length whose bending direction length is shorter than the cylindrical peripheral length of the press die is arranged so that both end surfaces of the bending direction are close to or abut on each other. It is characterized by having a cylindrical processing step of forming a cylindrical shaft that is press-bended into a cylindrical shape and the joint between the both end faces extends in the axial direction.

Further, the predetermined length is defined within a certain range based on a length obtained by removing an extension in a bending direction in press bending of the metal plate from a cylindrical peripheral length of the press die.

Moreover, after the said cylindrical processing process, it has the stress adjustment process of applying the external force to the said cylindrical axis | shaft and adjusting the stress which remains in the said cylindrical axis | shaft.

Further, it is characterized in that there is a curvature correcting step of bending the cylindrical shaft in the axial direction so that the joint faces the inner side of the arc between the cylindrical processing step and the stress adjusting step.

Further, the cylindrical processing step and the curvature correction step are continuously performed by progressive press processing.

1 is a side sectional view of an ink jet printer according to the present invention. (A) is a top view of a conveyance unit part, (b) is a side view of a drive system. (A) is a schematic block diagram of a conveyance roller mechanism, (b) is a schematic block diagram of a bearing. It is a top view which shows the metal plate as a base material of a roller main body. It is a figure which shows a part of press punching process. (A)-(c) is a figure which shows the bending process which concerns on this embodiment. (A)-(c) is a figure which shows the bending process following FIG. It is a figure explaining a curvature correction process. It is a figure which shows the relationship between the length of the short side of a flat plate part, the bending direction of a roller main body, and a bending amount. (A) The perspective view of a roller main body, (b) is a sectional side view of a joint. It is a figure which shows a stress adjustment process. It is a figure which shows the relationship between the distortion | strain given to the roller main body, and the amount of change with time. It is a figure which shows the change of the bending direction and bending amount of a roller main body before and behind a stress adjustment process. It is a figure which shows the other aspect of a stress adjustment process. It is a figure which shows a centerless grinding | polishing process. It is a figure which shows a high friction layer formation process. It is a figure which shows the modification of the side cut shape of a joint. (A)-(c) is a figure which shows the modification of a joint.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

FIG. 1 is a side sectional view of an ink jet printer according to an embodiment of the present invention.
2A is a plan view showing a transport unit of the ink jet printer, and FIG. 2B is a side view showing a drive system of the transport unit.

As shown in FIG. 1, an ink jet printer (printing apparatus) 1 includes a printer main body 3, a paper feeding unit 5 provided on the upper rear side of the printer main body 3, and a paper discharging unit provided on the front side of the printer main body 3. 7.

A paper feed tray 11 is provided in the paper feed unit 5, and a plurality of sheets (medium, recording medium, transport medium) P are stacked on the paper feed tray 11. Here, as the paper P,
Plain paper, coated paper, OHP (overhead projector) sheet, glossy paper, glossy film, and the like are used. Hereinafter, in the transport path of the paper P, the paper feed tray 11 side is referred to as an upstream side, and the paper discharge unit 7 side is referred to as a downstream side. A paper feed roller 13 is provided on the downstream side of the paper feed tray 11.

The paper feed roller 13 is configured to sandwich the paper P located at the uppermost part of the paper feed tray 11 with an opposing separation pad (not shown) and send it to the downstream side. Paper feed roller 13
A transport roller mechanism 19 is provided on the downstream side.

The transport roller mechanism 19 includes a transport roller 15 disposed on the lower side and a driven roller 17 disposed on the upper side.

The conveyance roller 15 sandwiches the paper P between the driven roller 17 and the drive unit 3 shown in FIG.
It is provided so as to be rotationally driven by zero. As a result, the transport roller 15 moves the paper P
Can be transported to a print head (printing unit) 21 arranged on the downstream side by a precise and accurate transport (paper feed) operation accompanying the transport printing process.

The print head 21 is held by a carriage 23, and the carriage 23 is configured to reciprocate in a direction orthogonal to the paper feeding direction (paper P transport direction). Printing processing (printing processing) by the print head 21 is controlled by the control unit CONT. A platen 24 is disposed at a position facing the print head 21.

The platen 24 is composed of a plurality of diamond ribs 25 arranged at intervals along the moving direction of the carriage 23.

The diamond rib 25 supports the paper P from below when printing on the paper P by the print head 21, and the top surface functions as a support surface. The distance between the diamond rib 25 and the print head 21 can be adjusted according to the thickness of the paper P.
As a result, the paper P can smoothly pass over the top surface of the diamond rib 25. On the downstream side of the diamond rib 25 and the print head 21, there is a paper discharge roller mechanism 2.
9 is provided.

The paper discharge roller mechanism 29 includes a paper discharge roller 27 disposed on the lower side and a paper discharge jagged roller 28 disposed on the upper side. The paper P is pulled out by the rotation of the paper discharge roller 27 and discharged. Yes.
Here, a description will be given of the relationship among the drive speeds of the driving unit 30 of the transport roller mechanism 19 and the paper discharge roller mechanism 29, the transport roller 15, and the paper discharge roller 27.

As shown in FIGS. 2A and 2B, the printer body 3 is provided with a transport motor 32 that is driven under the control of the control unit CONT. The drive shaft of the transport motor 32 is provided with a pinion 33, and the transport drive gear 35 is engaged with the pinion 33, and the transport roller 15 is inserted and connected to the transport drive gear 35. .
Under such a configuration, the transport motor 32 and the like serve as a drive unit 30 that rotationally drives the transport roller 15.

The transport roller 15 is provided with an inner gear 39 coaxially with the transport drive gear 35, and an intermediate gear 41 is engaged with the inner gear 39. The intermediate gear 41 has a paper discharge drive gear 43. Are in mesh. The rotation shaft of the paper discharge drive gear 43 is a shaft body 45 of the paper discharge roller 27 as shown in FIG.

Under such a configuration, the transport roller 15 of the transport roller mechanism 19 and the paper discharge roller 27 of the paper discharge roller mechanism 29 are driven by receiving the rotational driving force from the transport motor 32 that is the same drive source. It has become so.

The rotation speed of the paper discharge roller 27 is set to be faster than the rotation speed of the transport roller 15 by adjusting the gear ratio of each gear. Accordingly, the paper discharge speed of the paper discharge roller mechanism 29 is faster than the transport speed of the transport roller mechanism 19 by an increase rate.

The holding force (pressing force) of the paper P by the transport roller mechanism 19 is the discharge roller mechanism 2.
9 is set larger than the clamping force (pressing force) by 9. Therefore, when the transport roller mechanism 19 and the paper discharge roller mechanism 29 both hold the paper P, the paper transport speed is
Regardless of the paper discharge speed of the paper discharge roller mechanism 29, it is defined by the transport speed of the transport roller mechanism 19.

Next, the conveyance roller 15 and the conveyance roller mechanism 19 provided with the same will be described.
FIG. 3A is a diagram showing a schematic configuration of the transport roller mechanism 19, and FIG. 3B is a diagram showing a schematic configuration of the bearing.

The transport roller 15 includes a roller main body (cylindrical shaft) 16 formed into a cylindrical shape by pressing a metal plate, and a high friction layer (partial in the longitudinal direction (axial direction) of the surface of the roller main body 16 ( Medium support area) 50.

The roller body 16 is formed using a steel plate coil around which a metal plate such as a galvanized steel plate or a stainless steel plate is wound as a base material. The roller body 16 is formed by pressing (punching or bending) a metal plate on which a coil has been rewound. As shown in FIG. 10, the roller body 16 has a pair of end faces 61a, 61 of a metal plate that is bent and abutted (adjacent or abutted).
It has a joint (seam) 80 formed between b.

As shown in FIG. 3A, the high friction layer 50 is selectively formed in the central portion excluding both end portions of the roller body 16. The surface of the high friction layer 50 is fixed in a state where a sharp pointed portion of the inorganic particles is exposed, and exhibits a high frictional force.

The high friction layer 50 has a resin particle 10 μm in the formation region of the high friction layer on the surface of the roller body 16.
It is formed by selectively applying with a uniform film thickness of about 30 μm to form a resin film, spraying inorganic particles uniformly on the resin film, and then baking.
The resin particles are made of epoxy resin, polyester resin, etc., and have a diameter of 10-20.
Fine particles of about μm are preferably used. As the inorganic particles, aluminum oxide (alumina; Al2O3) or silicon carbide (SiC) adjusted to a predetermined particle size distribution by crushing treatment is used.
), Ceramic particles such as silicon dioxide (SiO 2) are preferably used.

As shown in FIG. 3A, both ends of the transport roller 15 are rotatably held by a bearing 26 integrally formed with the platen 24 (see FIG. 1).
As shown in FIG. 3 (b), the bearing 26 is formed in a U-shape that opens upward, and the conveyance roller 15 is fitted into this U-shaped portion so that the conveyance roller 15 is moved in the three directions of the front and rear sides and the lower side. From the pivot. Then, lubricating oil (lubricating liquid) such as grease is supplied (applied) to the contact surface between the bearing 26 and the transport roller 15 (the surface of the transport roller 15).
Further, an engaging portion (not shown) for engaging and connecting the inner gear 39 and the transport driving gear 35 so as not to rotate is formed at one end or both ends of the transport roller 15. Transport roller 15
In order to connect to various connecting parts, various forms of engaging portions can be formed.

The driven roller 17 is configured by a plurality of (for example, six) rollers 17 a arranged coaxially, and is arranged at a position facing and contacting the high friction layer 50 of the transport roller 15. A biasing spring (not shown) is attached to the driven roller 17 composed of these rollers 17a, whereby the driven roller 17 is biased toward the transport roller 15 side.

Accordingly, the driven roller 17 applies a predetermined pressing force (on the high friction layer 50 of the transport roller 15 (
The sheet P is in contact with the sheet P) and is rotated by the rotation operation of the transport roller 15. Moreover, the force which clamps the paper P between the conveyance roller 15 and the driven roller 17 becomes large, and the conveyance property of the paper P becomes more favorable.

The surface of each roller 17a of the driven roller 17 is subjected to a low wear treatment such as fluororesin coating in order to reduce damage caused by sliding contact with the high friction layer 50.
The conveyance roller 15, the bearing 26, the drive unit 30, the driven roller 17, and the like described above constitute a conveyance unit (conveyance device) 20 of the inkjet printer 1.

Next, the operation of the ink jet printer 1 will be described with reference to FIGS.
The inkjet printer 1 clamps the paper P located at the uppermost part of the paper feed tray 11 by the paper feed roller 13 and sends it out downstream. The fed paper P is a transport roller mechanism 1.
9 is reached. The transport roller mechanism 19 nips the paper P between the transport roller 15 and the driven roller 17, and transports the paper P at a constant speed toward the lower side of the print head 21 by a paper feeding operation by the rotational drive of the transport roller 15. The paper P conveyed below the print head 21 is a diamond rib 2.
5 is printed with high quality by the print head 21 while passing smoothly over the top surface of 5. The paper P printed by the print head 21 is sequentially discharged by the paper discharge roller 27 of the paper discharge unit 7.

Since the conveyance speed of the paper discharge roller mechanism 29 is set faster than the conveyance speed of the conveyance roller mechanism 19, the paper P is conveyed in a state where the back tension is applied. However, when the transport roller mechanism 19 and the paper discharge roller mechanism 29 both hold the paper P, the paper transport speed is defined by the transport speed of the transport roller mechanism 19. Therefore, even when the paper discharge roller mechanism 29 and the transport roller mechanism 19 simultaneously perform paper discharge and transport in this way, the transport speed of the paper is defined by the transport speed of the transport roller mechanism 19. Therefore, accurate and stable paper feeding (conveyance) without unevenness of conveyance is performed.

Then, by adopting a hollow cylindrical shaft as the roller body 16, the weight can be greatly reduced as compared with the case where a solid shaft is used. Moreover, the request | requirement with respect to the machinability of material becomes low compared with the case where a solid axis | shaft is used for the roller main body 16. FIG. Therefore, the roller body 1
It is possible to use a material that does not contain harmful substances such as lead as the material No. 6, and the environmental load can be reduced.

In addition, a high friction layer 50 is formed on the transport roller 15, and the driven roller 17 is disposed at a position where the driven roller 17 contacts the high friction layer 50. Therefore, the force for pinching the paper P between the transport roller 15 and the driven roller 17 is increased, and the transportability of the paper P is improved.

Moreover, the conveyance part 20 of this embodiment is provided with the conveyance roller 15 and the bearing 26 which supports this. Therefore, as described above, the transport roller 15 that provides high transport accuracy is provided with the bearing 26.
The paper P can be supported by the high friction layer 50 and conveyed with high accuracy. In addition, by adopting the hollow roller body 16 as the transport roller 15, the weight of the transport unit 20 can be greatly reduced compared to the case of using a solid shaft, and the environmental load can be reduced.

Further, the inkjet printer 1 of the present embodiment can transport the paper P with high accuracy by the transport unit 20 and can perform printing processing on the paper P with high printing accuracy. Further, by adopting the hollow roller body 16 as the transport roller 15, the weight of the entire apparatus can be greatly reduced as compared with the case where a solid shaft is used, and the environmental load can be reduced.

Next, the detailed structure and manufacturing method of the transport roller 15 (roller body 16) will be described with reference to FIG.
This will be described with reference to FIG.

FIG. 4 is a plan view showing a metal plate M as a base material of the roller body.
In order to manufacture the transport roller 15, as shown in FIG. 4, a metal plate M such as a cold rolled steel plate, a galvanized steel plate or a stainless steel plate having a thickness of about 1 mm is pressed (punched) in the transport direction. A continuous frame portion 66, a strip-shaped flat plate portion 60 extending in a direction intersecting the transport direction, and a connecting portion 67 that connects the frame portion 66 and the flat plate portion 60 are formed.
In this embodiment, the flat plate portion 60 is substantially rectangular, the short side 60a is parallel to the transport direction, and the long side 6
The die is punched so that 0b is orthogonal to the transport direction.

FIG. 5 is a diagram showing a part of the press punching process.
When forming the flat plate portion 60 by pressing (cutting) the metal plate M, the long side 60b (side portions 62a, 62b) of the flat plate portion 60 is cut diagonally.
Specifically, as shown in FIGS. 5A to 5C, the metal plate M includes a male mold 121 and a female mold 122.
It is punched by a press using And the upper surface edge part (conveyance direction of the metal plate M) of the female type | mold 122 is rounded by circular arc shape. For this reason, as shown in FIG. 5B, when the metal plate M is pressed out by the male mold 121 and the female mold 122, the portions to be the both side portions 62 a and 62 b of the flat plate portion 60 are the upper surfaces of the female mold 122. It is cut (sheared) in a curved state following the shape of the end. Immediately after the punching process, both side portions 62a and 62b of the flat plate portion 60 return to a flat state due to their elastic force.
Thereby, as shown in FIG.5 (c), the end surface 61 of the both sides 62a and 62b of the flat plate part 60 is shown.
a and 61b are formed to be inclined with respect to the main surfaces C1 and C2 of the flat plate portion 60. That is, the end surfaces 61a and 61b are inclined so as to have an acute angle with respect to a main surface C1 (described later, outer peripheral surface 16a) and an obtuse angle with respect to the main surface C2 (described later, inner peripheral surface 16b). It is formed.

The length of the short side 60a on the main surface C1 side (outer peripheral surface 16a side) is 35.55 mm as a reference.
The length is set within a range of about ± 100 μm. In this embodiment, the flat plate part 60 in which the length of the short side 60a is set to 35.55 mm is stably formed by adjusting the dimensions of the punching die.
The reference length of 35.55 mm as the length of the short side 60a is the minimum necessary for the end faces 61a and 61b to abut when the flat plate portion 60 is pressed into a cylindrical shape (diameter 12.2 mm). Because it is long.

The length of the short side 60a is defined in consideration of the elongation amount of the metal plate M (the flat plate portion 60) due to press working. In the present embodiment, a cold-rolled steel plate is used as the metal plate M. That is, when a galvanized steel plate, a stainless steel plate, or the like is used, the length of the short side 60a is a reference value that is different from the length described above.

A plurality of flat plate portions 60 and connecting portions 67 are formed at equal intervals in the conveyance direction of the metal plate M by repeatedly pressing the metal plate M while being conveyed intermittently by a conveyance unit (not shown).

Next, as shown in FIGS. 6A to 6C and FIGS. 7A to 7C, the flat plate portion 60 is pressed (bent) into a cylindrical shape (pipe shape), and both sides (long) End surfaces 61a, 6 of side 60b)
1b is brought close to or in contact (cylindrical shaft forming step).

Specifically, first, a female die (bending die) 141 and a male die (bending punch) 1 shown in FIG.
42, the flat plate portion 60 of the metal plate M is pressed, and both side portions 62a and 62b of the flat plate portion 60 are bent into an arc shape (preferably approximately ¼ arc).
In FIG. 6A, the flat plate portion 60 and the female die 14 are shown for easy understanding of each member.
1 and the male mold 142 are spaced apart from each other, but these members do not actually exist. The flat plate portion 60, the female mold 141, and the male mold 142 are in contact with each other. In almost all. This will be described later with reference to FIGS. 6B, 6C, and 7A to 7C.
The same applies to.

Next, after feeding the metal plate M in one direction, the second female die (bending die) 143 shown in FIG.
And the second male die (bending punch) 144 press the central portion of the flat plate portion 60 in the short side direction (bending direction). Then, the flat plate portion 60 is bent into an arc shape (preferably approximately ¼ arc).

Next, after feeding the metal plate M in one direction, the core die 147 is disposed inside the flat plate portion 60 as shown in FIG. Then, using the upper mold 145 and the lower mold 146 shown in FIG. 6C, as shown in FIGS. 7A to 7C, both end faces 61a of both side portions 62a and 62b of the flat plate portion 60.
, 61b are brought close to each other.

Here, the outer diameter of the core die 147 shown in FIG. 6C and FIGS. 7A to 7C is equal to the inner diameter of the hollow cylindrical roller body 16 to be formed. Further, as shown in FIG. 6C, the radius of the press surface 146c of the lower die 146 and the radius of the press surface 145a of the upper die 145 are each of the roller main body 16 considering the polishing margin (about 0.1 mm). It is equal to the radius of the outer diameter.
The finished size of the roller body 16 has a diameter (outer diameter) of 12.0 mm (radius 6.0 mm).
It is. And about 0.1 mm is provided from the outer peripheral surface 16a as polishing margin. Therefore,
The size of the roller body 16 after the press working is 12.2 mm in diameter (outer diameter) (radius 6.1 m).
m). That is, the lower die 146 (press surface 146c), the upper die 145 (press surface 145a).
) Is set to 6.1 mm. That is, the length (cylindrical circumferential length) of the press surfaces 145a and 146c formed by the upper die 145 and the lower die 146 is set to about 38.24 mm.

Further, as shown in FIGS. 7A to 7C, the lower mold 146 is a pair of left and right split molds, and the split molds 146a and 146b are configured to be able to move up and down independently.

That is, from the state shown in FIG. 6 (c), as shown in FIG. 7 (a), the left split mold 146a is brought close to the upper mold 145, and one side of the flat plate portion 60 is pressed to form a substantially semicircular shape. Bend to.
The upper mold 145 is also a pair of left and right split molds (refer to the split surface 145b) like the lower mold 146, and the upper mold on the same side is brought close to the split mold 146a in the process shown in FIG. Also good.

Next, as shown in FIG. 7B, the core die 147 is moved to the upper die 145 side slightly (so that the end surface 61a on one side and the end surface 61b on the other side can be brought close to each other) The split mold 146b on the other side is brought close to the upper mold 145, and the other side of the flat plate portion 60 is pressed and bent into a substantially semicircular shape.

Thereafter, as shown in FIG. 7C, the core mold 147 and the pair of split molds 146a and 146b are both brought close to the upper mold 145 to form a cylindrical roller body (hollow pipe) 16. In this state, the end surfaces 61a and 61b on both the left and right sides are in a state of facing each other. That is, in this cylindrical roller body 16, the end surfaces 61a and 61b on both sides of the flat plate portion 60 of the metal plate M as the base material are close to each other, and the joint 8 is formed between these end surfaces 61a and 61b.
0 is formed.

As described above, the length (cylindrical circumferential length) of the press surfaces 145a and 146c including the upper die 145 and the lower die 146 is set to about 38.24 mm. On the other hand, the short side 60 of the flat plate portion 60.
The length of a (the length in the bending direction) is set to 35.55 mm.
However, since the flat plate portion 60 (metal plate M) extends by press bending (cylindrical shaft forming step), the flat plate portion 60 (metal plate M) comes into contact with the end faces 61a and 61b. For this reason, the joint 80 between the end surfaces 61a and 61b is in a state without a gap.

In addition, when the length of the short side 60a is set to 35.45 mm, the joint 80 is in a state with a minute gap. On the other hand, when the length of the short side 60a is set to 35.65 mm, the end faces 61a and 61b abut against each other so as to lightly press each other, so that the joint 80 is substantially free of gaps.

FIG. 8 is a diagram for explaining a curvature correction process. Note that the seam 80 is 0 ° in the circumferential direction.
In this case, the curved state so as to swell in the 0 ° direction is + (plus), and the curved state so as to swell in the 180 ° direction is − (minus).
As shown in FIG. 8A, the roller body 16 formed through the cylindrical shaft forming step has a slightly curved shape in the axial direction. That is, the roller main body 16 molded through the press work has a bow shape. That is, the roller body 1 with respect to a straight line (ideal center axis 16d) connecting the centers of both ends of the roller body 16 (center of the cylinder).
The center portion of the actual center axis 16c of 6 is slightly shifted.

When the diameter of the roller body 16 after the cylindrical shaft forming step is about 12 mm and the length is about 300 mm to about 320 mm, the deviation amount of the central portion of the actual central axis with respect to the bending amount of the roller body 16 (ideal central axis 16d) ( The distance d) is about −15 μm. Roller body 1
In the bending direction 6 (warping direction), the joint 80 faces inward of the curvature (arc) (recessed in the direction of the joint 80).

When the length of the short side 60a of the flat plate portion 60 of the metal plate M is set to 35.55 mm, the central portion of the roller body 16 is such that the joint 80 faces the inside of the curve (arc). The curved shape deviates by about −15 μm from the axis 16d. Unless the length of the short side 60a is changed,
The direction and amount of bending of the roller body 16 are constant.

When the length of the short side 60a of the flat plate portion 60 of the metal plate M is set to 35.45 mm, the roller body 16 has a central portion so that the joint 80 faces the inside of the curve (arc). The curved shape deviates by about −18 μm from the ideal central axis 16d (see FIG. 8A).
On the other hand, when the length of the short side 60a of the flat plate portion 60 of the metal plate M is set to 35.65 mm, the roller body 16 has a central portion so that the joint 80 faces the outside of the curve (arc). The curved shape deviates from the ideal central axis 16d by about +50 μm (not shown).

Then, as the final process of the progressive press process, the cylindrical roller body 16 is corrected so as to be in a predetermined curved state (curvature correcting step).
In the bending correction process, as shown in FIG. 8B, the cylindrical roller body 16 is pressed (post-bending with a mold) by the upper mold 151 and the lower mold 152. The upper mold 151 and the lower mold 152 are
The cylindrical roller body 16 is not further bent in the circumferential direction, but the roller body 16 is curved (corrected) so as to have a bow shape in the axial direction.
In other words, the roller body 16 has a slightly curved shape in the axial direction through a cylindrical bending process by press working. Make it curved in an arc.

Specifically, as shown in FIG. 8C, when the joint 80 is 0 ° in the circumferential direction,
The curved state is corrected so as to swell in the 180 ° direction. That is, plastic deformation is performed so that the joint 80 is positioned inside the curve (arc) (depressed in the direction of the joint 80).

The bending amount (distance d1) at this time is corrected to 20 μm to 100 μm (plastically deformed).
More specifically, the roller body 16 has a diameter of about 12 mm and a length of about 300 mm to about 32 mm.
In the case of 0 mm, correction is made so as to be about 30 μm to 50 μm. When the diameter of the roller body 16 is about 6 mm and the length is about 300 mm to about 320 mm, the roller body 16 is corrected to be about 50 μm to 80 μm.

Since the curvature correction processing is uniformly applied to the roller body 16, the bending amount (correction amount) at that time is constant. That is, it is not necessary to adjust the bending amount (correction amount) each time. In other words, since it is not necessary to adjust the bending amount (correction amount) each time, it can be uniformly formed in a predetermined curved state by a progressive press.

FIG. 9 is a diagram showing the relationship between the length of the short side 60 a of the flat plate portion 60, the bending direction and the bending amount of the roller body 16. In the circumferential direction, the joint 80 is set to 0 °, the state curved so as to swell in the 0 ° direction is defined as + (plus), and the state curved so as to swell in the 180 ° direction is defined as − (minus).
In this way, the roller body 16 can be uniformly bent and straightened according to the length of the short side 60a (the main surface C1 side) of the flat plate portion 60 of the metal plate M. Body 16
This is because the bending direction and amount of bending are determined.

As shown in FIG. 9 and as described above, when the length of the short side 60a is set to 35.55 mm, the roller body 16 has the joint 80 so as to face the inside of the curve (arc). The central portion has a curved shape shifted by about 15 μm (−15 μm) from the ideal central axis 16d.
When the length of the short side 60a is set to 35.45 mm, the roller body 16 is
The central portion is 18 μm from the ideal central axis 16d so that the joint 80 faces the inside of the curve (arc).
The curved shape is shifted by about m (−18 μm).
Furthermore, when the length of the short side 60a of the flat plate portion 60 of the metal plate M is set to 35.65 mm, the roller body 16 has a central portion so that the joint 80 faces the outside of the curve (arc). The curved shape deviates from the ideal central axis 16d by about 50 μm (+50 μm).

In this embodiment, since the length of the short side 60a of the flat plate portion 60 of the metal plate M is fixed to 35.55 mm, it is not necessary to adjust the bending amount (correction amount) each time in the straightening process. . For this reason, the roller body 1 can be obtained by uniformly performing the curvature correction processing by the progressive press processing.
6 can be reliably corrected to be in a predetermined curved state.

In addition, when the length of the short side 60a of the flat plate portion 60 of the metal plate M is set to 35.45 mm or 35.65 mm, the bottom dead center of the upper die 151 or the lower die 152 is changed, or the upper die 151 is changed. And lower mold 1
The arrangement of 52 is switched up and down. This is because the amount of bending and the direction of bending of the roller body 16 differ depending on the length of the short side 60a, so that the amount of correction and the direction of correction are also different.
Even in this case, the bending correction processing is uniformly applied to the roller body 16, and the bending amount (correction amount) at that time is constant. Therefore, it can be formed in a predetermined curved state uniformly by the progressive press.

In this way, regardless of the length of the short side 60a, the roller body 16 is in a predetermined curved state, that is, the joint 80 faces the inside of the curve (arc), and the central portion is −20 from the ideal central axis 16d.
It becomes a curved shape that swings about μm to −100 μm.

The reason why the roller body 16 is corrected to a predetermined curved state is as follows.
In the manufacture of the roller body 16, after the metal plate M is pressed (bent) to form a cylindrical shaft (roller body 16), an external force is applied to the outer peripheral surface of the roller body 16 to adjust (homogenize) the residual stress. It is necessary to go through a stress adjustment step (details will be described later).
However, when a pressing force is applied to the roller body 16 during this stress adjustment step, the roller body 16 is deformed so that the joint 80 is located outside the curve (convex in the direction of the joint 80) ( The inventors have found a phenomenon of bending (see FIG. 13).

Therefore, prior to the stress adjustment process, the roller body 16 is bent (
In other words, the curvature is preliminarily curved in the opposite direction. In other words, the roller body 16 is curved (corrected) in advance so that the joint 80 is positioned inside the curve (arc), so as to cancel out the deformation of the roller body 16 in the subsequent stress adjustment process.

Thus, since all the roller main bodies 16 formed through the press work are subjected to curvature correction as the final process of the press work, if the joint 80 is set to 0 ° in the circumferential direction, 1
It is corrected to a curved state in the axial direction so as to swell slightly in the 80 ° direction.

As described above, while the metal plate M is intermittently fed in one direction, the punching process, the cylindrical bending process, and the curvature correcting process are sequentially performed by a press (sequential feeding press).
Then, after the flat plate portion 60 is formed in a cylindrical shape, the connecting portion 67 is cut by a not-shown cutting portion, and the hollow cylindrical roller body 16 is shown in FIGS. It becomes.
The end faces 61a and 61b that form the joint 80 are not limited to abutting but are close to each other (
This may be the case when the gap is open.

Next, a step of adjusting the stress remaining in the roller body 16 (stress adjustment step) is performed.
In this stress adjustment step, at least the high friction layer 5 of the outer peripheral surface 16a of the roller body 16 is used.
A pressing force is applied to a predetermined portion where 0 is formed. In the present embodiment, a case where a pressing force is applied to almost the entire outer peripheral surface 16a of the roller body 16 will be described as an example.
Specifically, as the stress adjustment step, a pressing force is applied to the roller body 16 using a roll leveler (roll leveler step).

In the roll leveler process, a plurality of pressing rollers are used. Here, as shown in FIG. 11, a case where two pressing rollers R1 and R2 are used will be described as an example.
The outer surface of the pressing roller R1 is formed in a convex shape (spindle shape). That is, it is formed in a cylinder whose diameter gradually changes so that both ends in the axial direction have a small diameter and the center has a large diameter.
On the other hand, the pressing roller R2 has an outer peripheral surface formed in a concave shape (a drum shape). That is, it is formed in a cylinder whose diameter gradually changes so that both ends in the axial direction have a large diameter and the center has a small diameter.

The two pressing rollers R1, R2 are arranged so that their rotation axes are parallel.
And between this press roller R1, R2, the roller main body 16 is pressed roller R1, R.
2 in parallel. That is, the roller body 16 is pressed by the pressing rollers R1 and R2.
Pinch.
And the desired pressing force can be given with respect to the clamped roller main body 16 by adjusting the distance between the axes of the pressing rollers R1 and R2. Further, the two pressing rollers R1 and R2 are rotated in different directions while the roller body 16 is sandwiched.
Thus, by rotating the pressing rollers R1 and R2 in different directions, the roller body 16 sandwiched between the pressing rollers R1 and R2 receives a pressing force while rotating.

Moreover, as shown in FIG. 11, a compressive force acts on the surface side in contact with the pressing roller R1 in the outer peripheral surface of the roller body 16. On the other hand, a tensile force acts on the surface of the outer peripheral surface of the roller body 16 that is in contact with the pressing roller R2. When the roller body 16 rotates, a tensile force and a compressive force are repeatedly applied to the outer peripheral surface of the roller body 16 while receiving a pressing force as a whole.

And while pressing roller body 16 with press rollers R1 and R2, roller body 16
Is moved relatively in the direction of the central axis.
That is, the pressing rollers R1 and R2 are fixed, and the roller body 16 is passed while rotating between the pressing rollers R1 and R2. Thereby, a pressing force is applied to the roller body 16 in order from the first end portion 16f to the second end portion 16s. The stress remaining in the roller body 16 is adjusted by this pressing force.

In the roll leveler process, a compressive force is applied to the roller body 16 so that plastic deformation occurs. As a forming material (metal plate M) of the roller body 16, a cold rolled steel plate (SP
When CC) is used, roll leveler processing (pressing rollers R1, R2) is performed so that a (compression) strain of about 0.25 to about 0.5% (about 0.0025 to about 0.005) is generated. The distance between the axes of R2 is adjusted.
Cold-rolled steel sheet (SPCC) is said to reach a plastic deformation region (plastic deformation occurs) when a strain of about 0.1% occurs. That is, in the roll leveler process, an external force (strain) of about 2 to about 5 times the external force (strain) at which plastic deformation starts to occur is applied to the roller body 16.
As a result, the roller body 16 is plastically deformed (compressed), and the internal stress is made uniform, and the change with time can be reliably suppressed.

That is, the roller body 16 is formed by bending the metal plate M by press working, so that both end surfaces 61a and 61b of the both side portions 62a and 62b of the flat plate portion 60 are brought close to or in contact with each other. However, the present inventors have found that the shape of the roller body 16 may change (warp occurs) with time (approximately several hundred hours).
It is considered that the stress (residual stress) remaining inside the roller body 16 during the press working is a deformation caused by gradually releasing (relaxing). In particular, the roller body 16 is heated when it undergoes a plating process or a high friction layer forming process, which will be described later, so that it is considered that the residual stress is easily released (relaxed). And when the residual stress of the roller main body 16 becomes non-uniform | heterogenous, it will be thought that the shape change of the roller main body 16 appears.
Specifically, with the passage of time, the roller body 16 is curved and deformed (warped) so that the joint 80 is positioned outside the curve. That is, when the joint 80 is 0 ° in the circumferential direction of the roller body 16, the roller body 16 is curved so as to swell in the 0 ° direction.

Thus, as described above, in the manufacture of the roller body 16, the residual stress is made uniform by passing through a stress adjustment process (roll leveler process), and the change with time is minimized. In particular, in the stress adjustment process (roll leveler process), an external force (strain) of about 2.5 to about 5 times the external force (strain) that causes plastic deformation to the roller body 16.
Therefore, the occurrence of changes with time can be minimized. Specifically, the amount of increase in the curvature of the roller body 16 over time is about 2 μm or less.

FIG. 12 is a diagram showing the relationship between the strain applied to the roller body and the amount of change over time.
FIG. 12 shows that 0%, 0.18%,.
24%, 0.29%, 0.32%, 0.34% (0, 0.0018, 0.0024,.
0029, 0.0032, 0.0034) is a graph in which the amount of deformation (the amount of increase in bending due to aging) is plotted after being left standing for several hundred hours or more (the number of samples is shown for each strain condition). 5).

0.29%, 0.32%, 0.34 with respect to the roller body 16 in the stress adjustment step.
% Strain, the deformation due to aging (bending increase) is about 2 μm at maximum.
It is suppressed to the extent.
And when 0.24% distortion is given with respect to the roller main body 16, the deformation | transformation amount (bending increase amount) by a temporal change will be about 4 micrometers at maximum. In addition, when a strain of 0.18% is applied to the roller body 16, the deformation amount (curve increase amount) due to change with time is about 6 μm at maximum. Further, when the roller body 16 is not subjected to the stress adjustment step (0% strain), the deformation amount (curve increase amount) due to the change with time is at least about several tens of μ.
m, which is about several hundred μm at the maximum (for this reason, the experimental data is not shown in FIG. 12).
In addition, when the distortion over 0.5% is given with respect to the roller main body 16, the joint 80 etc. of the roller main body 16 may deform | transform.
Thus, as indicated by the broken line in FIG. 12, the external force (0... About 2.5 to 5 times the external force (0.1% strain) that causes plastic deformation with respect to the roller body 16. 25-0.5%
) Can be suppressed to a minimum.

Moreover, as described above, prior to the stress adjustment step (roll leveler step), the roller body 16 is corrected in advance so that the joint 80 is positioned inside the curve (arc), so the stress adjustment step (roll leveler) The curvature (warp) of the roller body 16 that occurs in the step) can be offset.
That is, when a pressing force is applied to the roller body 16 during the stress adjustment step, the roller body 1
6 is deformed so that the joint 80 is located outside the curve (convex in the direction of the joint 80).
Bend). However, since the roller body 16 is previously corrected so that the joint 80 is positioned inside the curve (arc), the roller body 16 that has undergone the stress adjustment process (roll leveler process).
Is formed so that the linearity (cylindricity) falls within a predetermined range. Specifically, the bending amount of the roller body 16 is suppressed to about 20 μm or less.
Therefore, the total amount of bending of the roller body 16 is about 2 at the worst when a long time has elapsed.
2 μm or less (initial bending amount 20 μm + bending increase 2 μm).

FIG. 13 is a diagram illustrating changes in the bending direction and the bending amount of the roller body before and after the stress adjustment step. That is, a stress adjustment step (approx. 0.3% strain was applied) was performed on the plurality of roller bodies 16 curved in the 180 ° direction.
As a result, as shown in FIG. 13, the sample of the roller body 16 bent in the 180 ° direction (plot data □, ◇ in FIG. 13) has a bending amount of about 20 μm or less after the stress adjustment step. . In particular, when the bending amount before the stress adjustment process is about 20 μm to 100 μm or less (◇
), After the stress adjustment step, the bending amount is about 20 μm or less.

Thus, prior to the stress adjustment step, a desired straightness (cylindricity) is obtained by performing a curving correction step in which the roller body 16 is bent in the axial direction so that the joint 80 is inside the arc.
A roller body 16 having the following can be obtained. In particular, the length of the roller body 16 is 300.
In the case of mm to 320 mm, by providing a bending amount of about 20 μm to 100 μm, the bending amount can be reliably suppressed within a desired range (within about 20 μm).

When the stress adjustment step is not performed, the roller main body 16 having a desired linearity (cylindricity) is once formed, but the shape change due to aging is remarkable. Specifically, the amount of increase in the bending of the roller body 16 (the amount of bending due to changes over time) is about several tens of μm to several hundreds of μm.
For this reason, the linearity (cylindricity) of the roller body 16 is outside the desired range, and the defect rate of the roller body 16 is increased.

If the stress adjustment process is performed without performing the curvature correction process, the roller body 1
6 is suppressed to about 2 μm or less, but the bending amount of the roller body 16 is often about 100 μm or more through the stress adjustment process.
For this reason, the linearity (cylindricity) of the roller body 16 is outside the desired range, and the defect rate of the roller body 16 is increased.
On the other hand, as described above, according to the manufacturing process of the present embodiment, the defect rate of the roller body 16 is reduced and the yield is increased by going through both the curvature correction process and the stress adjustment process.

In addition, as a stress adjustment process, you may employ | adopt not only the roll leveler process mentioned above but the following processes.
As shown in FIG. 14 (a), a rolling process may be used.
The rolling process is so-called through-feed rolling (also called step rolling or through rolling) using two rolling rollers 201 and 202.
Specifically, as shown in FIG. 14A, the two rolling rollers 201 and 202 arranged so as to sandwich the roller body 16 are pressed against the roller body 16 with a predetermined pressure. In this state, the two rolling rollers 201 and 202 are rotated in the same direction. In the through feed rolling, when the rolling rollers 201 and 202 rotate, the roller body 16 moves in the axial direction while rotating in the direction opposite to the rotating direction of the rolling rollers 201 and 202.

In order to form the high friction layer 50 on the surface of the rolling rollers 201 and 202, spiral recesses 201a and 202a are formed, and the recesses 201a and 202a deform the surface of the roller body 16, On the surface of the roller body 16, a lattice-shaped uneven portion 203 is formed.

As described above, the uneven portion 2 is sequentially formed from the first end portion 16f of the roller body 16 to the second end portion 16s.
03 is formed. By forming the uneven portion 203, the stress remaining in the roller body 16 is adjusted. In addition, about the depth (unevenness | corrugation level | step difference) of the said uneven | corrugated | grooved part 203, it can set suitably in the range of 5 micrometers-50 micrometers.

In the rolling process, the axial dimensions of the rolling rollers 201 and 202 and the roller body 1
By making the axial dimension of 6 equal, a pressing force is applied to the entire roller body 16. Even in this case, the stress remaining in the roller body 16 is adjusted.

Moreover, as shown in FIGS. 14B and 14C, a rotation pressing process may be used as the stress adjustment process.
The rotation pressing process is performed in a state where the pressing member is pressed against the roller body 16.
Is a step in which the pressing member and the roller body 16 are relatively moved in the central axis direction of the roller body 16.

As a rotation press process, as shown in FIG.14 (b), the example which moves the roller main body 16 is mentioned. In this case, the pressing members R3 and R4 are fixed on the table TBL. The distance between the pressing member R3 and the pressing member R4 is set to be slightly smaller than the diameter of the roller body 16.

In this state, the roller body 16 is passed between the pressing member R3 and the pressing member R4 while rotating the roller body 16. The pressing member R <b> 3 and the pressing member R <b> 4 press the roller body 16 so as to be sandwiched. For this reason, a pressing force is applied from the first end 16 f of the roller body 16 to the second end 16 s. With this pressing force, the roller body 16
The residual stress is adjusted.

Moreover, as a rotation press process, as shown in FIG.14 (c), the example which moves the press member R5 without moving the roller main body 16 is mentioned. In this case, the roller body 16 is rotated around the central axis while the position of the roller body 16 is fixed. In this state, the pressing member R5 is moved to the roller body 1
6, the pressing member R <b> 5 is moved along the central axis of the roller body 16.

For this reason, a pressing force is applied from the first end 16 f of the roller body 16 to the second end 16 s. By this pressing force, the stress remaining in the roller body 16 is adjusted. In addition, it is preferable that the front-end | tip (part which contact | abuts the roller main body 16) of pressing member R5 is formed in the roller shape.

In each of the stress adjustment steps described above, a pressing force may be applied to the roller body 16 in a state where a core member (not shown) is inserted into the roller body 16. Thereby, it can avoid that the roller main body 16 deform | transforms with a pressing force.

Next, in the present embodiment, in order to increase the roundness of the roller body 16 and reduce the deflection,
Centerless polishing is performed.
In this polishing step, as shown in FIG. 15, the outer peripheral surface 16a of the roller body 16 is polished using a grindstone member GD formed in a columnar shape (or cylindrical shape). In the polishing step, a portion having a predetermined depth (thickness of about 20 μm to 100 μm; hereinafter referred to as “polishing depth”) is polished from the outer peripheral surface 16 a of the roller body 16.

The roller main body 16 is arranged between two grindstone members GD arranged with an interval smaller than the outer diameter of the roller main body 16 so that the roller main body 16 is in contact with the outer peripheral portions of the two grindstone members GD. . Thereafter, the two grindstone members GD are rotated in the same direction. A frictional force is generated between each grindstone member GD and the roller body 16 by the rotation of the two grindstone members GD.

The two grindstone members GD are formed so that the dimension in the longitudinal direction (the height direction of the cylinder) is larger than that of the roller body 16 so that the entire longitudinal direction of the roller body 16 can be polished at a time. It is preferable to use one. Further, when the grindstone member GD is rotated, in order to ensure a margin in the longitudinal direction of the roller main body 16, the roller main body is arranged at the center in the longitudinal direction of the grindstone member GD so that the entire longitudinal direction contacts the two grindstone members GD. 16 is preferably arranged.

The outer peripheral surface 16a of the roller main body 16 is polished while the roller main body 16 rotates in a direction opposite to the rotation direction of the grindstone member GD by the frictional force generated by the rotation of the grindstone member GD. For this reason, almost the entire outer peripheral surface 16a of the roller body 16 is uniformly polished, and the roundness of the roller body 16 becomes better than before the polishing step.

In addition, when performing the rolling process in the stress adjustment process, the outer peripheral surface 1 of the roller body 16
The uneven portion 203 formed on 6a is removed by polishing. Based on this, when the rolling process is performed, the uneven part 203 is formed so that the portion of the roller body 16 where the high friction layer 50 is formed is deeper than the polishing depth in the polishing process. . Further, the uneven portion 203 is formed so that the portion where the high friction layer 50 is not formed is shallower than the polishing depth.

If a grinding | polishing process is performed in this state, the part in which the high friction layer 50 is formed among the roller main bodies 16 will be in the state in which a part of uneven | corrugated | grooved part 203 remained. The high friction layer 5 of the roller body 16 is also provided.
A portion where 0 is not formed is in a state where the uneven portion 203 is removed. Therefore, in the process of forming the high friction layer 50, since the uneven portion 203 can be used, the manufacturing efficiency is increased.

After performing the polishing step, the roller body 16 having a high roundness and a small deflection amount is obtained. In addition, in this roller main body 16, the joint 80 in which the clearance gap between these both end surfaces 61a and 61b was narrowed is formed by narrowing between both end surfaces 61a and 61b.

When the roller body 16 is formed as described above, the roller body 16 is subjected to a surface treatment.
First, when a cold-rolled steel plate (SPCC) is used as a forming material (metal plate M) of the roller body 16, a plating process is performed. By forming a plating layer on the surface of the roller body 16, rust prevention is enhanced.

Next, a high friction layer 50 as shown in FIG. 3A is formed on the surface of the roller body 16.
As a method for forming the high friction layer 50, a dry method and a wet method (or a method using both of them) can be employed. In this embodiment, the dry method is preferably employed. Specifically, first, resin particles and inorganic particles are prepared as a material for forming the high friction layer 50. As the resin particles, fine particles having a diameter of about 10 μm made of an epoxy resin or a polyester resin are preferably used.

Further, as the inorganic particles, aluminum oxide (alumina; Al2O3) or silicon carbide (S
Ceramic particles such as iC) and silicon dioxide (SiO2) are preferably used. Among these, alumina is more preferably used because it has a relatively high hardness and functions well to increase frictional resistance, and is relatively inexpensive and does not hinder cost reduction. Therefore, in this embodiment, alumina particles are used as the inorganic particles.

As the alumina particles, those adjusted to a predetermined particle size distribution by crushing treatment are used. By being produced by crushing treatment, the alumina particles have a sharp end with a relatively sharp end, and the sharp end has a high frictional force.
The particle size of the alumina particles can be appropriately selected and adjusted.

When such resin particles and inorganic particles are prepared, first, the above-described resin particles are applied to the roller body 16. That is, the roller main body 16 is disposed in a painting booth (not shown), and the roller main body 16 is kept at a minus (-) potential in a single state.

The resin particles are then transferred to the roller body 16 using a tribogun of an electrostatic coating device (not shown).
The spray particles (resin particles) are charged to + (plus) high potential while spraying (spouting) toward the surface. Then, the charged resin particles are adsorbed on the outer peripheral surface of the roller body 16 to form a resin film.

Here, the formation of the resin film by spraying the resin particles corresponds to the formation region of the high friction layer 50 shown in FIG. That is, without performing the entire length of the roller main body 16, by masking both end portions with a tape or the like, only the central portion excluding these both end portions is performed as shown in FIG. That is, the resin film 51 is selectively formed only in a region corresponding to at least the central portion of the transport roller 15 including the roller body 16 that is in contact with the paper (medium) P to be transported.
In FIG. 16A and later-described FIGS. 16B and 16C, the joint 80 is not shown.

In the resin film 51, weak static electricity of about +0.5 KV remains after spray coating. In this spray coating, the roller body 16 is rotated around its axis, so that the resin film 51 is formed with a substantially uniform thickness over the entire circumference. The resin film 51 is formed to have a thickness of about 10 μm to 30 μm in consideration of the powder diameter of the alumina particles described above. About such a film thickness, it can adjust suitably with the ejection amount, ejection time, etc. of a resin particle.

Next, the roller body 16 on which the resin film 51 is formed is taken out from the above-described painting booth and transferred to another painting booth (not shown) by a handling robot or the like.
Then, the roller body 16 is rotated around the central axis. The roller body 16 is slowly rotated around its axis at a low speed of about 100 rpm to 500 rpm.

The alumina particles 95 are sprayed and sprayed from a corona gun disposed on the upper part of the coating booth, whereby the alumina particles 95 are formed on the resin film 51 formed on the roller body 16.
Is selectively electrostatically adsorbed. The alumina particles are selectively electrostatically adsorbed on the resin film 51 by masking both end portions of the roller body 16 with a tape or the like as in the formation of the resin film 51.

Then, as described above, since the weak static electricity (about +0.5 KV) remains in the resin film 51 of the roller body 16 by the electrostatic coating, the alumina particles 95 are resinated by this static electricity. Electrostatic adsorption is performed almost uniformly on the entire circumference of the film 51. The alumina particles 95 thus electrostatically adsorbed adhere to the outer peripheral surface of the roller body 16 using the resin film 51 as a binder in a state where the alumina particles 95 are in contact with the surface of the resin film 51 and partially enter.

In particular, the alumina particles 95 uniformly adhere to the surface of the resin film 51 that is not masked, whereby the roller body 16 has alumina particles (in the resin film 51 at the center thereof as shown in FIG. 16B). Inorganic particles 95 are dispersed and exposed. That is, the alumina particles 95 are
When the resin film 51 comes into contact with the electrostatic adsorption force, a part of the resin film 51 enters and the remaining part protrudes from the surface of the resin film 51. At that time, since the alumina particles 95 are likely to stand vertically to the surface of the roller body 16, the alumina particles 95 are uniformly distributed, and most of them are sharply pointed (top) facing outward. Adhere to.

Therefore, the alumina particles 95 exhibit a high frictional force due to the end portion protruding from the surface of the resin film 51. Here, in order for the alumina particles 95 to exhibit a necessary and sufficient frictional force against the paper P, the area occupied by the alumina particles 95 is 20 with respect to the area of the resin film 51.
% To 80% is preferable.

The application (spreading) of the alumina particles 95 is not limited to the application by the electrostatic coating method as long as the alumina particles 95 are slowly sprayed downward in the vertical direction, and a spray gun is used. The application (spreading) method may be used.

After the alumina particles 95 are spread and adhered on the resin film 51 in this way, the roller body 16 is heated at a temperature of about 180 ° C. to 300 ° C. for about 20 minutes to 30 minutes, and the resin film 51 is baked and cured. . As a result, the alumina particles 95 are fixed to the roller body 16. In this way, as shown in FIG. 16C, the high friction layer 50 in which the alumina particles (inorganic particles) 95 are dispersed and exposed in the resin film 51 is formed, and the transport roller 15 is obtained.

In this embodiment, resin particles are applied (sprayed) and alumina particles (inorganic particles) are applied (
Spraying) was carried out in separate painting booths, but it is of course possible to carry out in the same painting booth.

As described above, according to the present embodiment, after the roller body 16 is formed by bending, a pressing force is applied to at least a predetermined portion of the outer peripheral surface 16a of the roller body 16 where the high friction layer 50 is formed, Since we decided to adjust the residual stress on the roller body 16,
The residual stress is made uniform at least in the predetermined portion. For this reason, the shape change of the roller main body 16 in the predetermined portion can be suppressed. Thereby, the conveyance roller 15 of the stable shape can be manufactured.

Further, according to the present embodiment, in the stress adjustment step, the outer peripheral surface 16a of the roller body 16
Since the pressing force is applied to the entire surface, the residual stress on the entire surface of the roller body 16 is uniformly adjusted. Thereby, the shape of the conveyance roller 15 whole can be stabilized.

Furthermore, in the present embodiment, prior to the stress adjustment process, the roller body 16 is subjected to a stress correction process by performing a curving correction process in which the joint 80 is bent in the axial direction so that the joint 80 is inside the arc. The bending deformation (warping) of the main body 16 can be canceled out. Therefore, the roller body 16 having a desired linearity (cylindricity) can be obtained. In particular, when the length of the roller body 16 is 300 mm to 320 mm, the amount of bending can be reliably suppressed within a desired range by giving the amount of bending of about 20 μm to 100 μm.

Further, since the curving correction process is performed by pressing continuously after the cylindrical bending process, the roller body 16 that has been corrected to a desired curving state can be formed stably and reliably.
In particular, since the length in the bending direction (circumferential direction) of the flat plate portion 60 is set to be shorter than the cylindrical peripheral length of the press die in consideration of elongation during pressing, the roller body immediately after the cylindrical bending process 1
The bending amount and the bending direction of 6 are constant. Therefore, it becomes possible to perform the curvature correction process by pressing (sequential feeding press) continuously to the cylindrical bending process.

Therefore, when such a roller body 16 is used as the transport roller 15 of the inkjet printer 1 (transport roller mechanism 19), the printing paper P can be transported with high accuracy, and high-precision printing can be performed. It can be performed.

The various shapes and combinations of the constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

In the above embodiment, the roller body 16 has a configuration in which a steel plate coil around which a metal plate such as a rolled steel plate, a galvanized steel plate, or a stainless steel plate is wound is formed as a base material.
It is not limited to this.
The roller body 16 may be formed by using a flat metal plate as a base material, forming a metal plate having substantially the same shape and dimensions as the flat plate portion 60 from the flat metal plate, and processing the metal plate. Absent.
Therefore, in the above description or the following description, the present invention can be applied even when the flat plate portion 60 is replaced with the metal plate.

FIG. 17 is a diagram illustrating a modification of the cross-sectional shape of the joint 80.
As shown in FIG. 17A, the angle α formed by the end surface 61a and the outer peripheral surface 16a of the joint 80 is formed smaller than 90 °, and the angle β formed by the end surface 61b and the outer peripheral surface 16a is 9
You may form by the magnitude | size of 0 degree or more. That is, the end faces 61a and 61b at the joint 80.
The shape may be inclined in a predetermined direction with respect to the circumferential direction.
Further, as shown in FIG. 17B, either one of the end surfaces 61a and 61b is connected to the outer peripheral surface 16a.
It is possible to incline the other and make the other substantially orthogonal.
Further, as shown in FIG. 17 (c), both end surfaces 61a and 61b are substantially orthogonal to the outer peripheral surface 16a and the inner peripheral surface 16b, and the inner peripheral surface 16b side of the end surfaces 61a and 61b is close to or abuts. There may be.

As shown in FIG. 17C, when the end surfaces 61 a and 61 b are close to or abut on the inner peripheral surface 16 b side, the length of the short side 60 a of the flat plate portion 60 of the metal plate M is the peripheral length of the core die 147. Stipulated based on That is, the length is defined in consideration of the amount of elongation of the short side 60 a of the flat plate portion 60 from the peripheral length of the core die 147.
If the core mold 147 is not used, the upper mold 145 (press surface 145a) and the lower mold 146 are used.
The length is defined in consideration of the elongation amount of the short side 60a of the flat plate portion 60 and the plate thickness of the flat plate portion 60 from the peripheral length of the (press surface 146c).

When the roller main body 16 after the cylindrical machining process has almost no curvature or changes with time, the stress adjustment process and the curvature correction process may be omitted.
If the bending amount and the bending direction of the roller body 16 can be formed in a state opposite to the bending amount and the bending direction (can be canceled) by only the cylindrical bending process, the bending correction process is performed. It may be omitted.

Moreover, although the case where a curvature correction process is performed continuously with a progressive press was demonstrated, it is not restricted to this. You may perform a cylindrical bending process and a curvature correction process separately.
Although the cases of diameters of 12 mm and 6 mm have been described, the present invention is not limited thereto, and may be a case of a small diameter or a large diameter.

Further, the shape of the joint 80 of the roller body 16 is described as being a straight line parallel to the axial direction, but is not limited thereto. As shown in FIGS. 18A to 18C, various shapes can be adopted.
In addition, the case where the shape of the joint 80 shown to Fig.18 (a)-(c) may be provided in the whole or one part of the axial direction of the roller main body 16, and the case where these shapes are combined may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer, 15 ... Conveyance roller, 16 ... Roller main body (cylindrical shaft), 16a ... Outer peripheral surface, 16b ... Inner peripheral surface, 16c ... Central axis, 16d ... Ideal central axis, 50 ... High friction layer, 60 ... Flat plate Part, 60a ... short side, 61a, 61b ... end face (
End surfaces), 80 ... Joint, 145 ... Upper die (press die), 145a ... Press surface, 1
46 ... Lower mold (press mold), 146c ... Press surface, 147 ... Core mold (press mold), P ...
Paper, M ... Metal plate, C1, C2 ... Main surface, d1 ... Distance, R1, R2 ... Press roller, GD ... Whetstone member

Claims (5)

A metal plate formed in a predetermined length whose bending direction length is shorter than the cylindrical peripheral length of the press die is press-bended into a cylindrical shape so that both end surfaces in the bending direction are close to or in contact with each other. A method of manufacturing a cylindrical shaft, comprising: a cylindrical machining step in which a joint between the surfaces forms a cylindrical shaft extending in the axial direction. The said predetermined length is prescribed | regulated in the fixed range on the basis of the length remove | excluding the expansion | extension of the bending direction in the press bending process of the said metal plate from the cylindrical peripheral length of the said press die. The manufacturing method of the cylindrical shaft as described. 3. The manufacturing of the cylindrical shaft according to claim 1, further comprising a stress adjusting step of adjusting a residual stress in the cylindrical shaft by applying an external force to the cylindrical shaft after the cylindrical processing step. Method. 4. The curve correcting step of bending the cylindrical shaft in the axial direction so that the joint faces the inside of the arc between the cylindrical machining step and the stress adjusting step. The manufacturing method of the cylindrical axis | shaft of description. The cylindrical shaft manufacturing method according to claim 4, wherein the cylindrical processing step and the curvature correcting step are continuously performed by progressive press processing.

Images