JP2011126239A - Conveyance roller, conveyance unit, printing apparatus, and method for manufacturing conveyance roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyance roller capable of reducing a bend due to the elapse of time, conveyance unit, printing apparatus, and a method for manufacturing the conveyance roller. <P>SOLUTION: The conveyance roller 15 includes a roller main body 16 where a metal plate is subjected to press processing, a pair of ends 61a and 61b thereof is mutually opposed to be formed into a cylindrical shape and a joint 80 is contained between a pair of ends 61a and 61b. In a cross-sectional shape orthogonal to the axis O1 on the roller main body 16, a thickness Th1 of a joint opposing part 160 opposing with the joint 80 and the axis O1 interposed is smaller than a thickness Th2 of a joint part 161 on which the joint 80 is formed and a thickness of the roller main body 16 of a gap where the joint opposing part 160 and the joint part 161 are connected is configured so as to be gradually changed following from the joint opposing part 160 to the joint part 161. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a conveyance roller, a conveyance unit, a printing apparatus, and a method for manufacturing the conveyance roller.

 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 conveyance unit that conveys a recording medium that is an object to be conveyed. The transport unit has a transport roller for transporting the recording medium. A solid round bar member is generally used for the transport roller. The recording medium is held by the conveyance roller, and is conveyed by the rotation of the conveyance roller. Further, since printing is performed on the recording medium along with this conveyance, it is necessary to convey the recording medium with high positioning accuracy for proper printing.

 On the other hand, solid members have the problem of increasing weight and cost, and further weight reduction and cost reduction are being studied. Here, Patent Document 1 describes a technique for manufacturing a hollow cylindrical shaft by pressing and bending a metal plate so that a pair of end portions face each other.

JP 2006-289596 A

By the way, in order to convey a recording medium with high positioning accuracy, a cylindrical shaft with high roundness and excellent linearity with little warpage in the axial direction is required.
However, even in the case of a cylindrical shaft having excellent linearity at the time of manufacture, warping may occur over time, and the conveyance performance may deteriorate. The change with time of the cylindrical shaft appears as a warp in which the joint side formed when the pair of end portions of the metal plate are opposed to each other is convex.
Such warpage due to the aging of the cylindrical shaft is caused, for example, by the fact that internal stress generated by applying various processes to the joints to increase the roundness at the time of manufacture is generated due to lapse of time. Conceivable.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a transport roller, a transport unit, a printing apparatus, and a transport roller manufacturing method that can reduce warping due to the passage of time.

In order to solve the above-described problems, the present invention provides a cylindrical shaft that is formed in a cylindrical shape by pressing a metal plate so that a pair of ends thereof are opposed to each other, and has a joint between the pair of ends. In a cross-sectional shape perpendicular to the axis of the cylindrical shaft, the thickness of the joint facing portion that faces the joint and the shaft center is the joint where the joint is formed. The thickness of the cylindrical shaft between the joint facing portion and the joint portion is smaller than the thickness of the joint portion and gradually changes from the joint facing portion toward the joint portion. adopt.
By adopting such a configuration, in the present invention, in the cross-sectional shape orthogonal to the axial center of the cylindrical shaft, the thickness of the joint facing portion is smaller than the thickness of the joint portion, so the joint portion side is Even if it extends in the axial direction, the joint facing portion side tends to extend following it. For this reason, the warp that only the joint portion side extends in the axial direction and the joint becomes convex as in the prior art is reduced. In addition, by gradually changing the thickness from the joint-facing part to the joint part, stress concentration due to local steps or the like can be prevented from interfering with force transmission, and the warpage of the cylindrical shaft can be prevented. It is possible to prevent the occurrence of distortion that reduces the degree.

In the present invention, in the cross-sectional shape, the outer diameter shape of the cylindrical shaft is a circular shape centered on the shaft center, and the inner diameter shape of the cylindrical shaft is from the shaft center to the joint facing portion. The configuration is a circular shape eccentric to the side.
By adopting such a configuration, in the present invention, the circular shape of the inner diameter shape is decentered toward the joint facing portion side with respect to the circular shape of the outer shape, so that the joint facing portion is thicker than the thickness of the joint portion. The thickness can be reduced, and the thickness can be gradually and gradually changed from the joint-facing portion to the joint portion.

Moreover, in this invention, the structure provided with the conveyance roller as described previously and the drive device which rotationally drives the said conveyance roller is employ | adopted.
By adopting such a configuration, the present invention includes a transport roller that is less warped over time, so that the recording medium can be transported precisely over a long period of time.

In the present invention, a configuration is adopted in which a transport unit and a printing unit that performs a printing process on a recording medium transported by the transport unit are provided.
By adopting such a configuration, in the present invention, an accurate printing process for a recording medium can be performed over a long period of time by precise conveyance of the recording medium.

In the present invention, a metal plate is pressed, and a pair of end portions are opposed to each other to form a cylindrical shape, and a transport roller including a cylindrical shaft having a joint between the pair of end portions is manufactured. In the cross-sectional shape perpendicular to the axis of the cylindrical shaft, the thickness of the seam facing portion facing the seam and the axis is determined by the thickness of the seam where the seam is formed. And a thickness adjusting step for forming the thickness of the cylindrical shaft between the joint facing portion and the joint portion so as to gradually change from the joint facing portion toward the joint portion. The method of having
By adopting such a method, in the present invention, it is possible to manufacture a transport roller that is less warped over time.

Moreover, in this invention, the method of performing in the said press work is employ | adopted for the said thickness adjustment process.
By adopting such a method, in the present invention, in press working for forming a cylindrical shaft, the thickness can be adjusted at the same time, thereby preventing an increase in manufacturing steps. In addition, in the press working, by adjusting the thickness to make the thickness of the joint facing portion smaller than the thickness of the joint portion, internal stress that extends in the axial direction is added to the joint facing portion, It is possible to balance the internal stress with the joint portion side, and the warpage due to the passage of time is reduced.

1 is a side sectional view of an ink jet printer according to an embodiment of the present invention. (A) is a top view of a conveyance roller mechanism, (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 an enlarged view which shows the structure of the conveyance roller which concerns on embodiment of this invention. FIG. 5 is a sectional view taken along line AA in FIG. 4. It is a schematic block diagram of the manufacturing apparatus of the conveyance roller which concerns on embodiment of this invention. It is process drawing of the punching which concerns on embodiment of this invention. It is a top view of the metal plate after the punching which concerns on embodiment of this invention. (A)-(c) is process drawing of a bending process. (A)-(c) is process drawing of a bending process. It is sectional drawing of the roller main body after the thickness adjustment process which concerns on embodiment of this invention. It is process drawing of the centerless grinding | polishing process which concerns on embodiment of this invention. It is a schematic block diagram of the coating booth for forming the high friction layer which concerns on embodiment of this invention. (A)-(d) is the schematic which shows the structure of a roller main body. (A)-(c) is the schematic which shows the structure of a roller main body. (A) is a principal part perspective view of a roller main body, (b) is side sectional drawing. (A) is a principal part perspective view of a roller main body, (b) is a side view. (A) is a principal part perspective view of a roller main body, (b) is a side view. (A) is a principal part perspective view of a roller main body, (b) is a side view. (A)-(d) is a principal part top view of the metal plate which shows an expansion | deployment engaging part. (A)-(c) is a principal part top view of the metal plate which shows an expansion | deployment engaging part. (A) is a figure which shows the joint of a roller main body, (b) is a top view of a metal plate. (A) is a figure which shows the joint of a roller main body, (b) is a top view of a metal plate. FIG. 6 is a perspective view illustrating a relationship between a conveyance roller and a sheet during paper feeding. (A)-(c) is a figure for demonstrating the shape of a joint. (A)-(c) is a figure for demonstrating the shape 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.
FIG. 2A is a plan view showing a transport roller mechanism of the ink jet printer, and FIG. 2B is a side view showing a drive system of the transport roller mechanism.
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, or the like is 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 pinch the paper P located at the uppermost part of the paper feed tray 11 with an opposing separation pad (not shown) and send the paper P downstream. A transport roller mechanism 19 is provided on the downstream side of the paper feed roller 13.

  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 transport roller 15 is provided so that the paper P is sandwiched between it and the driven roller 17 and is rotationally driven by a drive unit (drive device) 30 (see FIG. 2). Thereby, the conveyance roller 15 becomes a structure which can perform the exact and exact conveyance (paper feeding) operation | movement accompanying a printing process (printing process) to the printing head (printing part) 21 arrange | positioned the paper P downstream. ing.

  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). The printing process 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. A paper discharge roller mechanism 29 is provided on the downstream side of the diamond rib 25 and the print head 21.

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 main 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 the speed increase rate.

  Further, the holding force (pressing force) of the paper P by the transport roller mechanism 19 is set larger than the holding force (pressing force) by the paper discharge roller mechanism 29. Therefore, when the transport roller mechanism 19 and the paper discharge roller mechanism 29 both hold the paper P, the paper transport speed is independent of the paper discharge speed of the paper discharge roller mechanism 29 and is transported by the transport roller mechanism 19. It is specified by speed.

Next, the conveyance roller 15 and the conveyance roller mechanism 19 provided with the same will be described.
FIG. 3A is a diagram illustrating a schematic configuration of the transport roller mechanism 19, and FIG. 3B is a diagram illustrating a schematic configuration of the bearing.
The transport roller 15 includes a hollow cylindrical roller body (cylindrical shaft) 16 and a high friction layer (medium support region) 50 formed on a surface of a part of the roller body 16 in the longitudinal direction (axial direction). ing.

  As shown in FIG. 3A, the high friction layer 50 is selectively formed in a central portion excluding both ends 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 is formed by selectively applying resin particles with a uniform film thickness of, for example, about 10 μm to 30 μm to the formation region of the high friction layer on the surface of the roller body 16. Inorganic particles are uniformly dispersed on the surface and then fired. As the resin particles, fine particles having a diameter of about 10 to 20 μm made of, for example, an epoxy resin or a polyester resin are preferably used. Further, as the inorganic particles, ceramic particles such as aluminum oxide (alumina; Al ₂ O ₃ ), silicon carbide (SiC), silicon dioxide (SiO ₂ ), etc., adjusted to a predetermined particle size distribution by crushing treatment are preferably used. It is done.

  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 or both ends of the transport roller 15. Since the transport roller 15 is connected 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, and thereby the driven roller 17 is biased toward the transport roller 15 side.

  Therefore, the driven roller 17 comes into contact with the high friction layer 50 of the transport roller 15 with a predetermined pressing force (clamping force with respect to the paper P), and rotates following 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.

Note that the surface of each roller 17a of the driven roller 17 is subjected to a low wear treatment such as a fluororesin coating in order to alleviate damage due to 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 constitute a conveyance unit (conveyance unit) 20 of the inkjet printer 1.

FIG. 4 is an enlarged view showing the configuration of the transport roller 15. 5 is a cross-sectional view taken along line AA in FIG.
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 main body 16 is bent so that a pair of end portions 61a and 61b of a metal plate obtained by rewinding the coil by press processing, which will be described later, face each other. A cylindrical shaft formed in a cylindrical shape. That is, the metal plate forming the roller body 16 is formed in a cylindrical shape in a state in which the winding by the coil remains so as to warp the inner peripheral surface side of the cylinder.

  The roller main body 16 has a joint 80 formed between a pair of end portions 61a and 61b of a metal plate which is bent and abutted as shown in FIG. In the roller body 16 of the present embodiment, the circumferential direction (bending direction) and the coil winding direction (metal plate rolling direction) are the same, and the joint 80 is substantially the same as the axial direction of the roller body 16. They are formed in parallel.

FIG. 5 shows a cross-sectional shape orthogonal to the axis O <b> 1 of the roller body 16. In the cross-sectional shape shown in FIG. 5, the roller main body 16 has a thickness Th1 of a joint facing portion 160 that faces the joint 80 with the axis O1 interposed therebetween, and is thicker than a thickness Th2 of the joint 161 where the joint 80 is formed. It is formed small. That is, the relationship is Th1 <Th2.
The joint facing portion 160 and the joint portion 161 refer to specific portions of the roller body 16 in a predetermined region facing each other on the straight line CL passing through the joint 80 and the axis O1.

  In this cross-sectional shape, the thickness of the roller body 16 between the joint facing portion 160 and the joint portion 161 is configured to gradually change from the joint facing portion 160 toward the joint portion 161. Yes. That is, the thickness of the roller main body 16 increases continuously from the thickness Th1 to the thickness Th2 as it goes to both sides in the circumferential direction.

In the present embodiment, in the cross-sectional shape shown in FIG. 5, the outer diameter shape of the roller body 16 (the shape of the outer peripheral surface 16a) is a circular shape centered on the axis O1. In the cross-sectional shape shown in FIG. 5, the inner diameter shape of the roller body 16 (the shape of the inner peripheral surface 16 b) is a circular shape that is eccentric by a predetermined distance from the axis O <b> 1 toward the joint facing portion 160. The axial center O2 of the inner diameter shape of the roller body 16 has moved a predetermined distance from the axis O1 to the joint facing portion 160 side on a straight line CL passing through the joint 80 and the axis O1.
The roller body 16 of the present embodiment has a shape that is line-symmetric with respect to the straight line CL in the cross-sectional shape shown in FIG.

The thickness difference between the thickness Th1 of the joint facing portion 160 and the thickness Th2 of the joint portion 161 is set within a range of 10% to 50% when the thickness Th2 is 100%. If the thickness Th2 of the joint portion 161 is 1.00 mm, the difference between the thickness Th1 and the thickness Th2 is in the range of 0.10 mm to 0.50 mm.
Specifically, in the example of the present embodiment, the difference between the thickness Th1 and the thickness Th2 is set to 0.15 mm, which is a 15% thickness difference. That is, the thickness Th1 is set to 0.85 mm, and the thickness Th2 is set to 1.00 mm.

Next, the manufacturing apparatus which manufactures the conveyance roller 15 of the said structure is demonstrated.
FIG. 6 is a schematic configuration diagram of an apparatus for manufacturing the transport roller 15 according to the embodiment of the present invention.
As shown in FIG. 6, the manufacturing apparatus 100 has a configuration in which an uncoiler 110, a leveler 120, a first press machine 130, and a second press machine 140 are arranged in one direction.
The manufacturing apparatus 100 also includes a conveyance unit (not shown) that sends the metal plate M unwound from the coil C in one direction, and a cutting unit (not shown) that cuts the processed cylindrical shaft (roller body 16) from the metal plate M. And.

The uncoiler 110 supports a cylindrical coil (steel plate coil) C around which a metal plate M is wound so as to be rotatable about an axis, and rewinds the coil C.
The leveler 120 includes a plurality of work rolls 121 arranged alternately above and below, and the metal plate M is flattened by passing the metal plate M between the upper and lower work rolls 121.

The first press machine 130 includes a male die (punch) 131 and a female die (die) 132, and is configured to punch the metal plate M into a predetermined shape by pressing.
The second press machine 140 includes a plurality of female dies (bending dies) 141 and 143 and male dies (bending punches) 142 and 144 arranged in one direction, and an upper die 145 and a lower die 146. The plate M is configured to be bent. Then, while the metal plate M is intermittently fed in one direction by a conveyance unit (not shown), the metal plate M is gradually brought closer to the cylinder by sequentially bending with different molds (sequential feed). ing.

Next, a method for manufacturing the transport roller 15 will be described.
First, for example, a coil C is prepared in which a metal plate M such as a cold rolled steel plate or an electrogalvanized steel plate having a thickness of about 0.8 mm to 1.2 mm is wound in the rolling direction. And the coil C is supported by the uncoiler 110 of the manufacturing apparatus 100, the coil C is rotated around an axis | shaft, and the metal plate M is rewound. The metal plate M unwound from the coil C has an arc-like winding in a side view in which the inner peripheral surface (lower surface C1) of the coil C is concave and the outer peripheral surface (upper surface C2) is convex. It is in the state. The rewound metal plate M is transported in one direction (rolling direction) by a transport unit (not shown) and reaches the leveler 120.

  The metal plate M that has reached the leveler 120 is flattened by a plurality of work rolls 121 arranged above and below, and the winding is adjusted. As a result, the metal plate M is flattened to such an extent that it can be processed by the first press machine 130, but the winding around which the inner peripheral side surface (lower surface C1) of the coil C is concave is left to some extent. . The metal plate M flattened by the leveler 120 is transported in one direction by a transport unit (not shown) and reaches the first press machine 130.

  The metal plate M that has reached the first press machine 130 is punched by a press using a male die 131 and a female die 132. Then, the die-cut metal plate M is formed as a base material of the roller body 16 by a punching process as shown in FIGS. In a later step, the metal plate M that is the base material of the roller body 16 is bent into a cylindrical shape with the upper surface C2 facing the male mold 131 shown in FIG.

  In this case, even in the case where the sagging sd, the shear surface sp, the fracture surface bs, and the burr (not shown) are formed on the metal plate M that has been die-cut as shown in FIG. The upper surface C <b> 2 where the sagging sd is formed is set to the outer peripheral side of the roller body 16. In other words, the lower surface C <b> 1 of the metal plate M continuing to the burr and the fracture surface bs is set to the inner peripheral side of the roller body 16.

Thereby, when forming the roller main body 16 which has a joint 80 (refer FIG. 5) by abutting a pair of edge part 61a, 61b of the metal plate M, the burr | flash and the unevenness | corrugation of the torn surface bs become obstacles, and a joint 80 can be prevented from opening.
Therefore, the accuracy of the joint 80 of the roller body 16 can be improved, and the transport roller 15 that can obtain high transport accuracy can be provided. Moreover, the burr | flash becomes the inner peripheral surface side of the roller main body 16, it can prevent protruding from the outer peripheral surface of the roller main body 16, and a burr removal process can be skipped and productivity can be improved.

FIG. 8 is a plan view of the metal plate M punched by the first press machine 130.
As shown in FIG. 8, the metal plate M is punched into a frame portion 66 that is continuous in the transport direction (rolling direction), a strip-shaped flat plate portion 60 that extends in a direction intersecting the transport direction, and a frame portion 66. A connecting portion 67 that connects the flat plate portion 60 is formed. In the present embodiment, the flat plate portion 60 has a substantially rectangular shape, and is stamped so that the short side 60a1 is parallel to the rolling direction and the long side 60b1 is orthogonal to the rolling direction. By repeatedly pressing the metal plate M while being transported intermittently by a transport unit (not shown), a plurality of flat plate portions 60 and connecting portions 67 are formed at equal intervals in the transport direction of the metal plate M.

The metal plate M punched by the first press machine 130 is conveyed by a conveyance unit (not shown) and reaches the second press machine 140 shown in FIG.
FIG. 9A to FIG. 9C and FIG. 10A to FIG. 10C are side views showing a bending process by the second press machine 140.

  The flat plate portion 60 of the metal plate M that has reached the second press machine 140 is bent by a press in a direction (rolling direction) parallel to the short side 60a1 shown in FIG. That is, bending is performed so that a pair of end faces along the long sides 60b1 and 60b1 on both sides of the flat plate portion 60 are brought close to each other. That is, as shown in FIGS. 9 (a) to 9 (c) and FIGS. 10 (a) to 10 (c), the pair of end portions 61a and 61b are opposed to face each other, and the flat plate portion 60 is formed in a cylindrical shape.

  Specifically, first, the flat plate portion 60 of the metal plate M is pressed with a female die (bending die) 141 and a male die (bending punch) 142 shown in FIG. 62b is bent into an arc shape (preferably approximately ¼ arc). In FIG. 9A, in order to make each member easy to understand, these members are shown with a space between the flat plate portion 60, the female die 141, and the male die 142. In reality, it does not exist, and the flat plate portion 60, the female die 141, and the male die 142 are in close contact with each other at their contact portions. The same applies to FIG. 9B, FIG. 9C, and FIG. 10A to FIG.

  Here, the male mold 142 is disposed so as to face the lower surface C1 (the lower surface of the flat plate portion 60 in FIG. 9) which is the inner peripheral side in the coil C shown in FIG. Further, the female die 141 is disposed so as to face the upper surface C2 (the upper surface of the flat plate portion 60 in FIG. 9) which is the outer peripheral side in the coil C shown in FIG. Thereby, both side parts 62a and 62b of the flat plate part 60 are bent to the lower surface C1 side which was the inner peripheral surface of the coil C.

  Next, after feeding the metal plate M in one direction, the second female die (bending die) 143 and the second male die (bending punch) 144 shown in FIG. The center part in the side direction (bending direction) is pressed. Then, the flat plate portion 60 is bent into an arc shape (preferably approximately ¼ arc) on the lower surface C1 side which is the inner peripheral side in the coil C shown in FIG.

  Next, after feeding the metal plate M in one direction, a cylindrical 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. 9 (c), as shown in FIGS. 10 (a) to 10 (c), the end portions of both side portions 62a and 62b of the flat plate portion 60 are used. 61a and 61b are brought close to each other.

  Here, the outer diameter of the core die 147 shown in FIG. 9C and FIGS. 10A to 10C is equal to the inner diameter of the hollow cylindrical roller body 16 to be formed. Further, as shown in FIG. 9C, 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 respectively the outer diameters of the roller body 16 in consideration of the later centerless polishing process. Is equal to the radius of. Further, as shown in FIGS. 10A to 10C, 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.

  First, from the state shown in FIG. 9 (c), as shown in FIG. 10 (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. 10B, the core die 147 is moved to the upper die 145 side slightly (so that the end 61a on one side and the end 61b on the other side can be brought close to each other). At the same time, 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. 10C, 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 portions 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 portions 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 a joint is formed between these end portions 61a and 61b. 80 is formed. Here, the lower surface C1 which is the inner peripheral side of the coil C shown in FIG. 6 becomes the inner peripheral surface 16b of the roller body 16, and C2 which is the outer peripheral side surface of the coil C becomes the outer peripheral surface 16a of the roller main body 16. ing. Thus, the roller body 16 is formed so that the flat plate portion 60 is wound around the core die 147. After the flat plate portion 60 is formed in a cylindrical shape, the connecting portion 67 is cut by a cutting portion (not shown) to form a hollow cylindrical roller body 16.

In the present embodiment, in order to obtain the cross-sectional shape of the roller body 16 described with reference to FIG. 5, the thickness of the roller body 16 is adjusted (thickness adjustment step) in the press work.
Specifically, in the press shown in FIG. 10C, the central portion in the short side direction of the flat plate portion 60 is adjusted in the plate thickness direction by strongly adjusting the pressing between the core die 147 and the upper die 145. Press. The pair of split molds 146a and 146b are both brought close to the upper mold 145, and the flat plate portion 60 is wound around the core mold 147 to form the roller body 16 having the cross-sectional shape shown in FIG. The thickness adjustment of the roller body 16 is performed, for example, when pressing the central portion in the short side direction of the flat plate portion 60 with the second female die 143 and the second male die 144 shown in FIG. Alternatively, it may be performed in advance.
As described above, in the present embodiment, in the press working for forming the roller body 16, the thickness can be adjusted at the same time, thereby preventing an increase in the manufacturing process.

FIG. 11 shows a cross-sectional shape orthogonal to the axis O1 of the roller body 16 with the thickness adjusted. In the cross-sectional shape shown in FIG. 11, the roller main body 16 has a thickness Th1 of the joint facing portion 160 facing the joint 80 and the axis O1, and the central portion in the short side direction of the flat plate portion 60 is pressed by the pressing. For this reason, it is formed smaller than the thickness Th2 of the joint portion 161 where the joint 80 is formed.
In this cross-sectional shape, the thickness of the roller body 16 between the joint facing portion 160 and the joint portion 161 is such that the cylindrical core die 147 is pressed against the upper die 145 side, and the upper die 145 and the lower die 146 are pressed. Or by pressing the center part of the flat plate part 60 in advance and pressing it using the cylindrical core mold 147 and the upper mold 145 and the lower mold 146, from the joint facing part 160. It forms so that it may change gradually as it goes to the joint part 161. FIG.

Next, in the present embodiment, centerless polishing is performed in order to increase the roundness of the formed roller body 16 and to reduce runout (warpage with respect to the axial direction). In this polishing step, for example, as shown in FIG. 12, the outer peripheral surface 16a of the roller body 16 is polished using a grindstone member GD formed in a columnar shape (or a cylindrical shape).
The roller main body 16 is arranged between two grindstone members GD arranged with a smaller interval than the outer diameter of the roller main body 16, and the roller main body 16 is in a state of being 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, for example. Due to the rotation of the two grindstone members GD, a frictional force is generated between each grindstone member GD and the roller body 16.

  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, at the time of rotation of the grindstone member GD, in order to ensure a margin in the longitudinal direction of the roller main body 16, for example, at the central portion in the longitudinal direction of the grindstone member GD, for example, the entire longitudinal direction contacts the two grindstone members GD. It is preferable to arrange the roller body 16.

  In this centerless polishing process, the outer peripheral surface 16a of the roller body 16 is polished while the roller body 16 rotates in the direction opposite to the rotation direction of the grinding wheel member GD due to the frictional force generated by the rotation of the grinding wheel member GD. Will be. For this reason, almost the entire outer peripheral surface 16a of the roller body 16 is uniformly ground, and the roundness of the roller body 16 is increased and the runout is reduced as compared with that before the centerless polishing step.

  When the roller body 16 serving as the cylindrical shaft according to the present invention is thus formed, a high friction layer 50 as shown in FIG. 3 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.

As inorganic particles, ceramic particles such as aluminum oxide (alumina; Al ₂ O ₃ ), silicon carbide (SiC), silicon dioxide (SiO ₂ ) and the like 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.

  Further, in this embodiment, the alumina particles are adjusted so that the particle diameter is in the range of 15 μm or more and 90 μm or less, and the weighted average particle diameter (average particle diameter) serving as the center diameter is 45 μm. Things are used.

  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 set to, for example, a minus (minus) potential in a single state.

  Then, the spray particles (resin particles) are charged to a + (plus) high potential while spraying (spraying) the resin particles toward the roller body 16 using a tribogun of an electrostatic coating apparatus (not shown). Let Then, the charged resin particles are adsorbed on the outer peripheral surface of the roller body 16 to form a resin film 51 (see FIG. 13).

  Here, the formation of the resin film 51 by spraying the resin particles corresponds to the formation region of the high friction layer 50 shown in FIG. That is, it does not carry out over the full length of the roller main body 16, for example, by masking the both ends with a tape etc., it carries out only to the center part except the both ends. That is, the resin film 51 is selectively formed only in the region corresponding to the central portion of the transport roller 15 including the roller body 16 that is at least the region in contact with the transported paper P.

  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 the 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 film thickness of, for example, 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 main 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 90 shown in FIG. 13 by a handling robot (not shown).
The coating booth 90 is provided with a pair of rotational drive members 91 and 91 at the lower portion thereof, and the rotational drive members 91 and 91 are provided with a chuck 92 for supporting the roller body 16 substantially horizontally. ing.

  Then, both ends of the roller body 16 are held and fixed to the chucks 92 and 92, and the chucks 92 and 92 are rotated by the rotation driving member 91. As a result, the roller body 16 is slowly rotated around its axis at a low speed of, for example, about 100 rpm to 500 rpm. Of course, the roller body 16 may be supported slightly obliquely.

  Further, a corona gun 93 is disposed at the upper portion of the painting booth 90, and the corona gun 93 moves on the shaft 94 in the left-right direction in FIG. An exhaust mechanism 96 is provided at the bottom of the painting booth 90. As a result, a slow air flow is formed in the painting booth 90 in the downward direction. The suction air volume of the exhaust mechanism 96 is set appropriately.

  Under such a configuration, the alumina particles 95 are sprayed and sprayed from the corona gun 93 while rotating the roller body 16 around its axis, whereby the alumina particles are formed on the resin film 51 formed on the roller body 16. 95 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.

At the time of electrostatic coating, the surface potential of the chuck 92 and the rotary drive member 91 is set to be substantially equal to the potential of the roller body 16, and the inner surface potential of the coating booth 90 is electrically neutral and substantially zero. To do. This is to prevent the alumina particles 95 from the corona gun 93 from being adsorbed to parts other than the roller body 16. In order to keep the inner surface potential of the coating booth 90 electrically neutral, it is desirable to manufacture the coating booth 90 using a steel plate having an inner surface electrical resistance of, for example, about 10 ¹¹ Ω.

  The electric potential applied to the corona gun 93 is set to zero V, and the pressure of the air supplied to the corona gun 93 is set to a low value of about 0.2 Mpa. Next, while moving the corona gun 93 in the left-right direction in FIG. 13, alumina particles 95 with substantially zero potential are blown out from above, and the alumina particles 95 are naturally dropped by their own weight in the vertical direction.

  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.

  Here, in this embodiment, since the inner surface potential of the coating booth 90 is electrically neutral and substantially zero, and the air flow in the coating booth 90 is formed in a slow downward flow, the alumina particles 95 naturally falls down vertically due to its own weight. Below the dropping direction, the horizontally supported roller body 16 is slowly rotating around its axis, so that the alumina particles 95 are dispersed almost uniformly on the outer peripheral surface of the roller body 16.

  Therefore, the alumina particles 95 are uniformly attached to the surface of the resin film 51 that is not particularly masked, and the alumina particles (inorganic particles) 95 are dispersed and exposed in the resin film 51. That is, when the alumina particles 95 come into contact with the resin film 51 by electrostatic attraction, a part of the alumina particles 95 enters the resin film 51 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% to 80% with respect to the area of the resin film 51. Is preferred.

  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. For example, a spray gun is used. The application (spreading) method may be used.

  When the alumina particles 95 are spread and adhered on the resin film 51 in this way, the roller body 16 is heated, and the resin film 51 is baked and cured. By this heating, the alumina particles 95 are fixed to the roller body 16. If it does so, the conveyance roller 15 (refer FIG. 3) which has the high friction layer 50 of the state which the alumina particle (inorganic particle) 95 disperse | distributed and exposed in the resin film 51 will be obtained.

  In the present embodiment, the application (spraying) of the resin particles and the application (spraying) of the alumina particles (inorganic particles) are performed in different painting booths. However, it may be performed in the same painting booth. It is.

Next, the operation of the ink jet printer 1 having the above configuration and the operation of the transport roller 15 having the above configuration will be described.
As shown in FIG. 1, 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 to the downstream side. The fed paper P reaches the transport roller mechanism 19. 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 printed with high quality by the print head 21 while smoothly passing over the top surface of the diamond rib 25. 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.

  Here, when the paper P is supported and transported by the high friction layer 50 of the transport roller 15, torque acts on the roller body 16. Then, stress acts in a direction in which the joint 80 (see FIG. 4) between the pair of end portions 61a and 61b of the metal plate forming the roller body 16 opens. If the joint 80 of the roller body 16 is opened, the transport roller 15 may not be in contact with the paper P uniformly, and transport unevenness may occur.

  However, in the present embodiment, the roller main body 16 of the transport roller 15 is formed of a metal plate in which the winding by the steel plate coil remains, and is formed in a cylindrical shape in which the lower surface C1 that is the inner peripheral side of the coil is the inner peripheral surface. Has been. The winding of the metal plate by the steel plate coil is a warp such that the lower surface C1, which is the inner peripheral surface of the steel plate coil, becomes a concave surface. In other words, the metal plate forming the roller body 16 remains so as to warp toward the inner peripheral surface side of the roller body 16.

  Therefore, winding does not act at least in the direction in which the joint 80 of the roller body 16 is opened. Therefore, it is possible to make it difficult to open the joint 80 of the roller main body 16 as compared with the case where the winding that warps to the outer peripheral surface side of the roller main body 16 remains. That is, according to the present embodiment, even when stress is applied in the direction in which the joint 80 of the roller body 16 is opened, the joint 80 can be prevented from opening, and transport with high transport accuracy can be obtained. A roller 15 can be provided.

  Moreover, the circumferential direction (bending direction) of the roller main body 16 and the winding direction (rolling direction of a metal plate) of a steel plate coil are the same. Therefore, the bending direction of the metal plate forming the roller body 16 can be matched with the direction of warping due to winding. Thereby, the winding of the metal plate which forms the roller main body 16 acts in the direction which closes the joint 80 of the roller main body 16. Accordingly, the opening of the joint 80 of the roller body 16 can be more effectively prevented.

  In addition, by adopting a hollow cylindrical shaft for 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, it is possible to use a material that does not contain harmful substances such as lead as the material of the roller body 16, 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.

  Further, in the transport roller 15, the roller body 16 in the cross-sectional shape shown in FIG. The thickness of the roller body 16 between the joint portion 160 and the joint portion 161 is smaller than the thickness Th2 of the joint portion 161 so that the thickness gradually changes from the joint opposing portion 160 toward the joint portion 161. It is configured. For this reason, the time-dependent change of the conveyance roller 15 by progress of time can be suppressed, and the shape with the high roundness and the linearity with few curvature with respect to an axial direction can be maintained over a long period of time.

  That is, in the press shown in FIG. 10 (c), in order to bring the pair of end portions 61a and 61b of the flat plate portion 60 into contact with each other without a gap, the pair of end portions 61a and 61b are combined and crushed in the circumferential direction. Press. As a result, the crushing allowance escapes in the axial direction of the roller body 16, and an internal stress that tends to extend in the axial direction is generated in the joint portion 161 in which the joint 80 shown in FIG. 5 is formed. When this internal stress is released over time, a change with time appears as a warp in which the joint 80 formed when the pair of end portions 61a and 61b face each other is convex.

  However, since the thickness Th1 of the joint facing portion 160 is smaller than the thickness Th2 of the joint portion 161 in the cross-sectional shape orthogonal to the axis O1 of the roller body 16, the joint portion 161 side extends in the axial direction over time. However, the seam facing portion 160 side tends to extend following this. For this reason, the warp that only the joint portion 161 side extends in the axial direction and the joint 80 becomes convex as in the prior art is reduced. Further, by gradually changing the thickness from the joint facing portion 160 to the joint portion 161, the occurrence of stress concentration due to a local step or the like between them and the interference of force transmission are prevented, and the axial extension due to the change over time is prevented. It is possible to prevent the warpage of the roller main body 16 and the occurrence of distortion that reduces the roundness due to the above.

  Moreover, in the press work which forms the roller main body 16 as described above, when the center portion of the flat plate portion 60 is pressed and the thickness adjustment is performed so that the thickness of the joint facing portion 160 is smaller than the thickness of the joint portion 161. Further, by adding an internal stress that causes the crushing margin to extend in the axial direction also to the joint facing portion 160 and balancing the internal stress with the joint portion 161 side, the joint portion 161 over time. Since the timing at which the internal stress on the side is released and the timing at which the internal stress on the joint facing portion 160 side is adjusted can be adjusted to be the same, warpage due to the passage of time can be further reduced.

  The difference between the thickness Th1 of the joint facing portion 160 and the thickness Th2 of the joint portion 161 is set within a range of 10% to 50% when the thickness Th2 is 100%. That is, when the thickness difference is less than 10%, the thickness difference between the joint facing portion 160 and the joint portion 161 becomes small, so that the above-described effects are not sufficiently obtained, and the conventional joint 80 side is convex. It becomes difficult to prevent the occurrence of warpage. On the other hand, if the thickness difference is larger than 50%, the strength of the joint facing portion 160 is weakened, and conversely, the roller body 16 may be warped and may cause distortion that lowers the roundness. For this reason, by setting the thickness difference between the thickness Th1 of the joint facing portion 160 and the thickness Th2 of the joint portion 161 within a range of 10% or more and 50% or less when the thickness Th2 is 100%, The effects described above can be sufficiently obtained.

  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 can obtain high transport accuracy can be supported and rotated by the bearing 26, and the paper P can be supported by the high friction layer 50 and transported 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. In addition, since the transport unit 20 includes the transport roller 15 that is less warped over time, the paper P can be transported accurately over a long period of time.

  In addition, 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 over a long period of time. 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.

  As described above, according to this embodiment, it is possible to obtain the transport roller 15 that can reduce warping due to the passage of time. Further, the transport unit 20 that can accurately transport the paper P over a long period of time is obtained. In addition, the ink jet printer 1 capable of performing an accurate printing process on the paper P over a long period of time is obtained.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and modifications can be made as appropriate without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the roller body 16 has a configuration in which a steel plate coil around which a metal plate such as a galvanized steel plate or a stainless steel plate is wound is formed as a base material, but is not limited thereto. No. For example, 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. I do not care. Therefore, for example, in the above description or the following description, the present invention is applicable even when the flat plate portion 60 is replaced with the metal plate.

Further, for example, an opening 170 may be provided in a part of the joint 80 formed in the roller body 16 as shown in FIG.
As shown in FIG. 14B, the joint 80 formed in the roller body 16 has a groove shape in which the inner peripheral sides of the pair of end portions 61a and 61b are in close contact with each other and the outer peripheral sides are separated from each other. Alternatively, the joint 80 may be formed as a gap with the end portions 61a and 61b slightly spaced apart without the pair of end portions 61a and 61b coming into contact with each other. Since the joint 80 is formed over the entire length of the transport roller 15, when the grease G supplied to the bearing 26 adheres to the surface of the transport roller 15, the grease G flows through the joint 80 by capillary action. become. In particular, as the joint 80 (the maximum distance d1 between the end portions 61a and 61b) is reduced in order to improve the strength of the transport roller 15, the capillary phenomenon of the grease G becomes stronger, and the grease G moves along the joint 80. It becomes easy to flow.

  Therefore, as shown in FIG. 14C, an opening 170 is provided in a part of the joint 80 formed in the roller body 16. As shown in FIG. 14C, the opening 170 is formed by notches 176 and 177 provided at a pair of end portions 61 a and 61 b that form the joint 80. When the end portions 61a and 61b are brought into contact with each other, the maximum distance d2 between the notches 176 and 177 is set to be about 1 mm or more, for example, and functions as the opening 170.

  The opening 170 is provided in a region excluding a region where the high friction layer 50 is formed and a region supported by the bearing 26 in the joint 80 formed over the entire length of the transport roller 15 (roller body 16). That is, the high friction layer 50 is formed at substantially the center of the transport roller 15, and both ends of the transport roller 15 are supported by the bearings 26, so that the transport roller 15 is provided with at least two openings 170.

  The opening 170 is provided for the purpose of preventing the grease G (lubricating oil) supplied (applied) to the bearing 26 from reaching the high friction layer 50 along the joint 80 (the gap between the end portions 61a and 61b). That is, by providing the opening 170 in a part of the joint 80, the capillary phenomenon of the grease G is stopped. Specifically, by providing the opening 170 between the region supported by the bearing 26 and the region where the high friction layer 50 is formed in the joint 80, the grease G is prevented from reaching the high friction layer 50. is doing. Then, by adjusting the size of the opening 170 (the maximum distance d2 between the pair of notches 176 and 177), the capillary phenomenon of the grease G can be reliably stopped.

  Note that the present invention is not limited to the case where the notches 176 and 177 for forming the opening 170 are formed in each of the pair of end portions 61 a and 61 b that form the joint 80. That is, as shown in FIG. 14D, a notch 178 is formed only in one (for example, the end 61a) of the pair of end portions 61a and 61b that form the joint 80, and the notch 178 and the end portions are formed. The opening 170 may be formed by 61b. The shape of the opening 170 is not limited to a rectangle, and may be a circle or the like.

  Further, as shown in FIG. 15, the shape of the joint (indicated by reference numeral 276 in FIG. 15) formed in the roller body (indicated by reference numeral 271 in FIG. 15) is changed to the shape shown in FIG. May be. That is, in the joint 276, the first end 274 and the second end 275 are in contact with each other on the outer peripheral surface 271 a side of the roller body 271. The gap between the first end 274 and the second end 275 gradually becomes wider from the radially outer side toward the inner side. Moreover, the shape of the 1st end part 274 and the 2nd end part 275 is the same shape over the axial direction full length of the roller main body 271. As shown in FIG.

 The roller body 271 has a plating layer 278 formed on the surface thereof. The plating layer 278 is formed on the end surfaces of the outer peripheral surface 271a, the inner peripheral surface 271b, the first end portion 274, and the second end portion 275. The plating layer 278 may be formed using any method of electroplating and electroless plating, or may be formed by overlapping a plurality of plating layers. As the type of plating, for example, nickel plating, zinc plating, chromium plating or the like is used.

  Further, the first angle α formed by the first end portion 274 and the outer peripheral surface 271a and the second angle β formed by the second end portion 275 and the outer peripheral surface 271a are both formed smaller than 90 °. ing.

  The first end 274 and the second end 275 of the joint 276 are in contact with each other on the outer peripheral surface 271a side, and the smoothness on the outer peripheral surface 271a side is improved at the connecting portion. Therefore, even if the transport roller 15 rotates, the outer peripheral surface can stably contact the paper P. For this reason, the paper P can be conveyed with high accuracy.

  As shown in FIG. 15B, the shape of the joint 276 is such that the first angle α formed by the first end 274 of the joint 276 and the outer peripheral surface 271a is smaller than 90 °, The second angle β formed by the end portion 275 and the outer peripheral surface 271a may be formed with a size of 90 ° or more. That is, the first end portion 274 and the second end portion 275 in the connection portion of the joint 276 may be shaped to be inclined in a predetermined direction with respect to the circumferential direction.

  The shape of the joint 276 is formed through the following steps. That is, after the metal plate 270 is formed by punching in progressive press processing, end adjustment processing is performed on the first end portion 274 and the second end portion 275 of the metal plate 270, and the first end portion 274 is processed. And the inclination with respect to the outer peripheral surface 271a of the 2nd edge part 275 is adjusted.

As shown in FIG.15 (c), the inclination with respect to the outer peripheral surface 271a of the 1st end part 274 and the 2nd end part 275 is adjusted by press work. With this adjustment, the first angle α formed by the first end portion 274 and the outer peripheral surface 271a and the second angle β formed by the second end portion 275 and the outer peripheral surface 271a are both smaller than 90 °. Become. Further, in the metal plate 270 having a thickness t, the length _{L 3} of a side of the inner circumferential surface 271b is smaller than the side length _{L 4} of the outer circumferential surface 271a.

  Accordingly, when the cylindrical roller body 271 is formed by bending the metal plate 270, the first end 274 and the second end 275 are in contact with each other at least on the outer peripheral surface 271a side.

  In FIG. 15, if the first end portion 274 and the second end portion 275 are tapered at a predetermined angle by performing a press for end adjustment processing, the first end portion 274 and the second end portion 275 are internally connected. When stress is accumulated and they are made to face each other, as a result, an internal stress that tends to extend in the axial direction is generated in the joint portion where the joint 276 is formed. By gradually changing the thickness smaller than the joint portion where the joint 276 is formed, it is possible to suppress a change with time due to the same effect as the above-described embodiment.

  Further, as described above, one or both of the both ends of the roller body 16 (conveyance roller 15) are connected to various connection components such as the conveyance drive gear 35 and the inner gear 39 shown in FIG. An engaging portion is formed. For example, as shown in FIGS. 16 (a) and 16 (b), the opposite positions of the roller body 16 composed of a cylindrical pipe (hollow pipe), that is, two formation surfaces defining the diameter of the roller body 16 are provided. The through holes 71a and 71a can be formed, respectively, and an engagement hole (engagement portion) 71 including the pair of through holes 71a and 71a can be formed. According to the engagement hole 71, the connecting component 72 such as a gear can be fixed by a shaft, a pin or the like (not shown).

  In addition, as shown in FIGS. 17A and 17B, a D-cut engagement portion 73 can be formed at the end of the roller body 16. The engaging portion 73 is formed at the end of a cylindrical hollow pipe (roller body 16), and an opening partly cut out in a rectangular shape in plan view as shown in FIG. 73a. As a result, the outer shape of the side surface of the end portion is formed in an apparent D shape as shown in FIG.

  Therefore, by engaging a connecting part (not shown) such as a gear with the engaging portion 73 formed in an apparent D shape, the connecting part is idled with respect to the roller body 16 (conveying roller 15). It can be installed without. Further, since the engaging portion 73 is formed with a groove-like opening 73a that communicates with the internal hole of the hollow pipe (roller body 16), the connecting part can be connected to the roller body by using the opening 73a. It can be attached to 16 without making it idle. Specifically, by forming a convex portion on the connecting component and fitting the convex portion into the opening 73a, it is possible to prevent idling.

  Further, as shown in FIGS. 18A and 18B, an engaging portion 74 having a groove 74a and a D-cut portion 74b can be formed at the end of the roller body 16. In this engagement portion 74, the D cut portion 74b is formed at the outer end of the roller body 16, and the groove 74a is formed inside the D cut portion 74b. As shown in FIG. 18A, the groove 74 a is formed by cutting the roller body 16 approximately half in the circumferential direction. The D-cut portion 74b has an opening 74c extending in a direction orthogonal to the groove 74a outside the groove 74a, and has a pair of bent pieces 74d and 74d on both sides of the opening 74c. That is, as shown in FIG. 18B, when the pair of bent pieces 74d and 74d are bent toward the central axis side of the roller body 16, the portions corresponding to the bent pieces 74d and 74d are The roller body 16 is recessed from the circular outer peripheral surface.

  Therefore, a connecting part (not shown) such as a gear is engaged with the groove 74a or the D-cut portion 74b without causing the connecting part to idle with respect to the roller body 16 (conveying roller 15). Can be attached. In addition, the engaging portion 74 can be attached to the roller body 16 without making it idle by using the opening 74c formed between the bent pieces 74d. Specifically, by forming a convex portion on the connecting component and fitting the convex portion into the opening 74c, it is possible to prevent idling.

  Further, as shown in FIGS. 19A and 19B, an engaging portion 75 having a groove 75 a and an opening 75 b can be formed at the end of the roller body 16. In the engaging portion 75, the opening 75b is formed at the outer end of the roller body 16, and the groove 75a is formed inside the opening 75b. As shown in FIG. 19A, the groove 75a is formed by cutting the roller body 16 approximately half in the circumferential direction. In the opening 75b, a part of the roller body 16 is cut out in a rectangular shape in plan view outside the groove 75a, and thereby the outer shape of the end side surface is formed in an apparent D shape as shown in FIG. Is.

  Therefore, a connecting part (not shown) such as a gear is engaged with the groove 75a or an apparently D-shaped part formed by the opening 75b, thereby connecting the connecting part to the roller body 16. It can be attached to the (conveying roller 15) without idling. Also, in this engaging portion 75, similarly to the engaging portion 73 shown in FIGS. 17 (a) and 17 (b), the connecting component is attached to the roller body 16 without being idle by using the opening 75b. be able to.

  In order to form such engagement holes 71 and engagement portions 73, 74, and 75, the roller body 16 obtained by pressing the flat plate portion 60 is further subjected to cutting or the like. You can also. However, in that case, the cost and time efficiency are reduced by adding a separate processing step to the roller body 16 only for forming the engaging portion. Therefore, in the manufacturing method of the present invention, before the roller main body 16 is pressed in the second pressing step, a deployment engaging portion that becomes an engaging portion is formed on the flat plate portion 60 by pressing in the first pressing step. Thereafter, when the flat plate portion 60 is pressed into the roller body 16 in the second pressing step, the engaging portion is simultaneously formed.

  Specifically, when the metal plate M wound in a coil shape is punched into an elongated substantially rectangular plate-like flat plate portion 60, the metal plate M is obtained simultaneously with the processing from the large metal plate M to the small flat plate portion 60. At the end of the flat plate portion 60, a developed engagement portion such as a notch shape, a projecting piece shape, a hole shape, or a groove shape is formed.

  For example, as shown in FIG. 20 (a), a pair of through holes 71a and 71a are processed at predetermined positions on the end of the flat plate portion 60, and these are used as the deployment engaging portion 76a, thereby pressing the flat plate portion 60. By processing, a pair of through-holes 71a and 71a can be made to oppose, and the engagement hole 71 shown to FIG. 16 (a), (b) can be formed.

  Also, as shown in FIG. 20B, the flat plate portion 60 is pressed by cutting the end portion of the flat plate portion 60 into a predetermined shape to form a deployment engagement portion 73c composed of a pair of cutout portions 73b and 73b. By processing, the engaging portion 73 shown in FIGS. 17A and 17B can be formed.

  Further, as shown in FIG. 20 (c), the flat plate portion 60 is pressed into a predetermined shape by cutting out the end portion of the flat plate portion 60 into a predetermined shape, thereby pressing the flat plate portion 60 as shown in FIG. 18 (a). , (B) can be formed. That is, the engagement portion 74 can be formed by forming a pair of notches (recesses) 74e, 74e and a pair of protrusions 74f, 74f as the deployment engagement portion 76b. However, in this example, after the flat plate portion 60 is pressed, it is necessary to bend the pair of projecting pieces 74f and 74f inward to form a bent piece 74d. Is slightly insufficient to increase

  Therefore, as shown in FIG. 20 (d), the flat plate portion 60 is press-processed by cutting the end portion of the flat plate portion 60 into a predetermined shape by cutting out the end portion of the flat plate portion 60 as shown in FIG. 19 (a). , (B) can be formed. That is, the engaging portion 75 can be formed by forming a pair of notches (recessed portions) 75c and 75c and a pair of projecting pieces 75d and 75d as the deployment engaging portion 76c. In this example, when the flat plate portion 60 is pressed, the pair of projecting pieces 75d and 75d are also bent in an arc shape to form the opening 75b shown in FIG. 19B between the projecting pieces 75d and 75d. Can do. Therefore, it is not necessary to add further processing to the roller main body 16 formed by press processing, and thereby the cost and time efficiency of the processing steps can be sufficiently increased.

  Here, in the example shown in FIGS. 20B to 20D, the flat plate is formed so that the engaging portions 73, 74, and 75 shown in FIGS. 17, 18, and 19 are formed with the joint 80 interposed therebetween. Deployment engaging portions 73 c, 76 b, 76 c are formed at both ends of the portion 60. Thus, the joint 80 of the roller main body 16 to form can be made shorter than the length of this roller main body 16 by forming the expansion | deployment engaging parts 73c, 76b, and 76c in both ends. Accordingly, it is possible to suppress deformation of the roller body 16 due to the end portions 61a and 61b partially contacting and interfering when the joint 80 is formed.

  However, the above-described configuration is not limited to this, and as shown in FIGS. 21A to 21C, the development engagement portions are not formed at both ends of the flat plate portion 60, but in the width direction (bending direction). ) In the vicinity of the center line. That is, as shown in FIG. 21A, the engaging portion 73 shown in FIG. 17 can be formed by forming a deployment engaging portion 76d made of an elongated rectangular cutout at the end. Further, by forming the deployment engagement portion 76e formed of a T-shaped notch as shown in FIG. 21B, the engagement portion 74 shown in FIG. 18 can be formed, and further, FIG. By forming the developed engaging portion 76f formed of a substantially T-shaped notch as shown in c), the engaging portion 75 shown in FIG. 19 can be formed.

  Thus, if the expansion | extension engagement parts 76d-76f are formed in the vicinity of the centerline in a bending direction, the engagement parts 73-75 obtained from these expansion | extension engagement parts 76d-76f can be formed more accurately. .

As described above, when the small metal plate (flat plate portion 60) is formed from the large metal plate M by pressing in the method for manufacturing the transport roller 15, the unfolding engagement portion is also formed at the same time. When pressing 60, the engagement hole (engagement part) 71 and the engagement parts 73, 74, 75 are formed from the development engagement part, and after the roller body 16 is formed, the engagement part There is no need to add a separate processing step only for the formation of the film.
Therefore, since the cost and time required for the added processing steps are not required, the cost of the transport roller 15 itself can be sufficiently reduced, and the productivity is improved. In particular, when the large metal plate is reduced in size, the development engaging portion is formed in a lump so that the process can be further simplified.

  As shown in FIG. 4, in the transport roller 15 (roller body 16) according to the present embodiment, the joint 80 is formed to be parallel to the central axis of the roller body 16 formed of a cylindrical hollow pipe. However, the present invention is not limited to this.

  For example, as shown in FIG. 22A, the joint 83 may be formed in a wavy line formed of a curve such as a sine wave. In order to form the joint 83 in this manner, as a metal plate serving as a base material, as shown in FIG. 22 (b), a flat plate portion having a long and substantially rectangular shape and both long sides thereof being formed in a wavy line shape. Using 60b, press working is performed so that the straight line indicated by reference numeral 16d is the central axis. In addition, since a pair of long sides formed in a wavy line are brought close to each other by press working, naturally, when one long side becomes a peak portion between corresponding points, a trough is formed on the other long side. Conversely, when one long side is a valley, the other long side is a mountain.

  Further, as shown in FIG. 23A, the joint 84 may be formed in a wavy shape bent in a hook shape. In order to form the joint 84 in this way, as shown in FIG. 23 (b), the metal plate serving as the base material has an elongated and substantially rectangular shape, and both long sides thereof are bent in a wavy shape. Using the formed flat plate portion 60c, pressing is performed so that the straight line indicated by reference numeral 16d is the central axis. Also in the flat plate portion 60c, between the portions corresponding to each other in the pair of long sides formed in a wavy line, when one long side is a peak, the other long side is a valley, and conversely, When the long side is a trough, the other long side is a crest.

  Moreover, about a joint, it is not limited to the example shown in FIG. 22, FIG. 23, A various shape is employable. For example, you may combine the wavy line which consists of a curve shown to Fig.22 (a), and the bent wavy line shown to Fig.23 (a).

  In this way, if the joints 83 and 84 are formed so as to overlap only at a plurality of points with respect to a straight line parallel to the central axis of the cylindrical pipe (roller body 16), the conveyance having the roller body 16 is performed. When the roller 15 transports the paper P in cooperation with the driven roller 17, that is, when feeding the paper, the transport speed of the paper P becomes constant, and transport unevenness is more reliably prevented.

  That is, as shown in FIG. 24, the portion where the transport roller 15 contacts the paper P when the paper is fed is basically a straight line L on the outer peripheral surface, that is, a straight line L parallel to the central axis 16c. Therefore, when the joint 80 of the transport roller 15 (roller body 16) is parallel to the central axis 16c of the roller body 16 as shown in FIG. 4, the entire joint 80 is temporarily (instantaneous) The contact with the paper P. Then, since the groove is not formed due to the joint 80 as described above in the transport roller 15 of the present embodiment, there is no problem, but the groove is temporarily formed due to the joint 80. Then, this groove is temporarily and simultaneously in contact with the paper P, so that the entire width of the paper P is temporarily in contact with the groove due to the joint 80. As a result, the groove has a dent compared to the other outer peripheral surface of the transport roller 15, and the contact resistance with respect to the paper P is small. Therefore, the transport speed of the paper P is temporarily reduced, resulting in uneven transport. End up.

  Therefore, if the joints 83 and 84 are formed as shown in FIGS. 22A and 23A, even if grooves are formed due to these joints, these grooves are not fed to the paper. At this time, only a plurality of points are in contact with the paper P at the same time. Therefore, there is almost no change in the contact resistance as compared with the case where the other surface of the transport roller 15 hits, whereby the transport speed of the paper P becomes constant, and transport unevenness is prevented.

  Moreover, about the joint of the conveyance roller 15 (roller main body 16) which consists of a cylindrical hollow pipe, in addition to the example mentioned above, for example, as shown to Fig.25 (a), it is parallel to the central axis of the roller main body 16. It may be formed having a rectangular wave-like bent portion 85 composed of a straight portion 85a and a straight portion 85b orthogonal thereto. Even in the joint having such a bent portion 85, if a groove is temporarily formed due to the joint, the groove is simultaneously formed over the entire width of the sheet P during paper feeding. Since there is no contact, the conveyance speed of the paper P becomes substantially constant, and uneven conveyance is prevented.

  Further, the bent portion 85 may be formed over the entire length of the roller body 16 as shown in FIG. 25 (b), and the central portion thereof as shown in FIG. 25 (c). You may selectively form in the both ends except. When the bent portions 85 are formed only at both ends as shown in FIG. 25C, a central straight portion 86 parallel to the central axis of the roller body 16 is formed between the bent portions 85.

  Further, when the bent portion 85 is formed only at both end portions and the central portion between them is the central straight portion 86, the formation region of the high friction layer 50 shown in FIG. Preferably.

  When the bent portion 85 is formed at the joint, and thus the bent portion 85 is made to be a fitting portion with unevenness, the bent portion 85 (fitting portion) is fitted as designed, and the tip of the convex portion and the tip It becomes difficult to make it approach (match) without a gap between the recesses corresponding to. Therefore, when the bent portion 85 is formed over the entire length of the roller body 16, the roller body 16 is likely to be distorted or twisted. Therefore, if the bent portions 85 are formed only at both ends as shown in FIG. 25C, it is possible to suppress the occurrence of such distortion and twist. In particular, by setting the central portion corresponding to the high friction layer 50, which is an area in direct contact with the paper P, to the central straight portion 86 instead of the bent portion 85, the area in direct contact with the paper P is distorted or twisted. Can be reliably prevented.

  In addition, about the joint of the conveyance roller 15 (roller main body 16) which consists of a cylindrical hollow pipe, in addition to the above-mentioned example, for example, as shown in FIG. You may make it non-parallel with respect to the center axis | shaft of the roller main body 16, and form the angle (alpha) of the front end side of the convex piece 88b in the bending part 88 to an obtuse angle (less than 180 degrees). In this way, when the pair of end portions are brought close to each other in the press working of the metal plate, the tip of the convex piece 88b can be easily fitted into the corresponding concave portion, and therefore, the roller body 16 is distorted or twisted. Can be suppressed.

  Further, in the structure in which the bent portions 85 are formed only at both ends as shown in FIG. 25C, the bent portions 85 are shown in FIG. 22A as shown in FIG. 26B, for example. The wavy line 89a may be replaced with a curved line 89a, and may be replaced with the bent wavy line 89b shown in FIG. 23 (a) as shown in FIG. 26 (c).

  Further, a joint may be formed by combining the rectangular wavy bent portion 85 shown in FIG. 25A and the wavy line 89a made of the curve shown in FIG. The joint 85 may be formed by combining the portion 85 and the bent wavy line 89b shown in FIG.

  22, 23, 25, and 26, when a concave portion and a convex portion are formed at a pair of end portions of the metal plate, respectively, and the convex portion is press-fitted into the concave portion with the pair of end portions facing each other. The internal stress that tends to extend in the axial direction is generated in the joint portion. By changing, it is possible to suppress the change with time by the same effect as the above-described embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet printer (printing apparatus), 15 ... Conveyance roller, 16 ... Roller main body (cylindrical shaft), 20 ... Conveyance part (conveyance unit), 21 ... Print head (printing part), 30 ... Drive part (drive device), 60 ... Flat plate portion, 61a ... End portion, 61b ... End portion, 80 ... Joint, 160 ... Joint facing portion, 161 ... Joint portion, M ... Metal plate, O1 ... Axis, O2 ... Axis, P ... Paper (recording medium), Th1 ... thickness, Th2 ... thickness

Claims (6)

A metal roller is pressed, and a pair of end portions are opposed to each other and formed into a cylindrical shape, a transport roller including a cylindrical shaft having a joint between the pair of end portions,
In a cross-sectional shape orthogonal to the axis of the cylindrical shaft,
The thickness of the seam facing portion that faces the seam across the axis is smaller than the thickness of the seam where the seam is formed,
The conveyance roller, wherein a thickness of the cylindrical shaft between the joint facing portion and the joint portion is gradually changed from the joint facing portion toward the joint portion. In the cross-sectional shape,
The outer diameter shape of the cylindrical shaft is a circular shape centered on the axis,
The conveying roller according to claim 1, wherein an inner diameter shape of the cylindrical shaft is a circular shape that is eccentric from the axial center toward the joint facing portion side. The transport roller according to claim 1 or 2,
And a drive unit that rotationally drives the transport roller. A transport unit according to claim 3;
And a printing unit that performs a printing process on the recording medium conveyed by the conveyance unit. A method of manufacturing a transport roller comprising a cylindrical shaft formed by pressing a metal plate and having a pair of ends opposed to each other and formed into a cylindrical shape, and having a joint between the pair of ends,
In a cross-sectional shape orthogonal to the axis of the cylindrical shaft,
The thickness of the seam facing portion facing the seam across the axis is smaller than the thickness of the seam portion where the seam is formed, and the seam facing portion and the seam portion. A method for manufacturing a transport roller, comprising: a thickness adjusting step of forming a thickness of the cylindrical shaft during tying so as to gradually change from the joint facing part toward the joint part.   The said thickness adjustment process is performed in the said press work, The manufacturing method of the conveyance roller of Claim 5 characterized by the above-mentioned.

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