JP2011137533A - Cylindrical shaft, conveyance roller, conveyance device, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical shaft with a stabilized shape, a conveying roller with the cylindrical shaft, a conveyance apparatus with the conveying roller, and a printer. <P>SOLUTION: The cylindrical shaft is formed by press working a metal plate to bring a pair of their ends to face each other so as to form a cylindrical shape, and has a joint section between the pair of the ends. The joint section has: a first joint part which extends in the center axial direction of the cylindrical shaft; and a second joint part which is provided on the opposite side of the first joint part across the center axis of the cylindrical shaft and connected to the end of the first joint part, and extends in the center axial direction of the cylindrical shaft. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cylindrical shaft, a conveyance roller, a conveyance device, and a printing device.

  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. Here, Patent Document 1 describes a technique in which a metal plate is bent and formed 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 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 joint of the cylindrical shaft changes with time, and the shape of the cylindrical shaft may change accordingly. This shape change is considered to be an effect of, for example, stress remaining when the cylindrical shaft is bent, and the residual stress being relaxed over time.

  The present invention has been made in view of the above-described circumstances. The object of the present invention is to provide a cylindrical shaft having a stable shape, a transport roller using the cylindrical shaft, a transport device using the transport roller, and a printing device. It is to provide.

  The cylindrical shaft according to the present invention is a cylindrical shaft that is formed in a cylindrical shape with a pair of end portions facing each other by press working, and has a joint between the pair of end portions, and the joint is the cylindrical shaft A first connecting portion extending in the direction of the central axis, and provided on the opposite side of the first connecting portion across the central axis, connected to an end of the first connecting portion, and in the direction of the central axis And a second connecting portion extending.

  According to the present invention, since the first joint portion and the second joint portion constituting the joint are provided on the opposite side across the central axis of the cylindrical shaft, the effect of relaxation of the residual stress is the first joint portion. And the second connecting portion will be offset. Thereby, the shape change of a cylindrical axis | shaft can be suppressed and the cylindrical axis | shaft of a stable shape can be provided.

Moreover, it is preferable that the said 2nd connection part is divided | segmented and provided in the position which pinches | interposes the said 1st connection part in the said center axis direction.
According to the present invention, since the second connecting portion is divided and provided at a position sandwiching the first connecting portion in the central axis direction, the influence of relaxation of residual stress is canceled while being distributed in the central axis direction of the cylindrical shaft. Can do.

Moreover, it is preferable that a said 1st connection part is provided in the center part of the said central axis direction of the said cylindrical shaft.
According to the present invention, since the first connecting portion is provided in the central portion in the central axis direction of the cylindrical shaft, the influence of relaxation of residual stress can be more evenly distributed in the central axis direction of the cylindrical shaft.

Moreover, it is preferable that a said 2nd connection part is provided in the position shifted | deviated to the circumferential direction of the said cylindrical shaft.
According to the present invention, since the second connecting portion is provided at a position shifted in the circumferential direction of the cylindrical shaft, the effect of relaxation of the residual stress can be dispersed in the circumferential direction of the cylindrical shaft.

Moreover, it is preferable that the said 1st connection part and said 2nd connection part are formed in the dimension substantially equal to the said center axis direction.
According to the present invention, since the first connecting portion and the second connecting portion are formed to have substantially the same dimension in the central axis direction, the influence of the relaxation of the residual stress is almost canceled out. Thereby, deformation of the cylindrical shaft can be prevented more reliably.

Moreover, it is preferable that the pair of end portions forming the second connecting portion have an uneven portion for fitting one end portion and the other end portion of the pair of end portions.
According to the present invention, since one end portion of the pair of end portions forming the second connecting portion and the other end portion can be fitted in the concavo-convex portion, the shape of the cylindrical shaft can be further stabilized. it can.

A conveyance roller according to the present invention includes a cylindrical shaft that is rotatably provided, and a conveyance unit that is provided on a surface of the cylindrical shaft and conveys a medium to be conveyed. It is used.
According to the present invention, since the medium to be transported can be transported using a cylindrical shaft having a stable shape, the intended transport accuracy can be maintained.

Moreover, it is preferable that the said conveyance part has a high friction layer in which the inorganic particle contained.
According to the present invention, since the transport unit has the high friction layer containing inorganic particles, the transport accuracy can be increased and the transport accuracy can be maintained.

  Moreover, it is preferable that the said 1st connection part of the said cylindrical shaft is provided in the said conveyance part.

  According to this invention, since the 1st connection part of a cylindrical shaft is provided in the conveyance part, it can avoid that the conveyance state of a conveyance part varies.

Moreover, it is preferable that the said 2nd connection part of the said cylindrical shaft is provided in the part remove | deviated from the said conveyance part.
According to the present invention, since the second connecting portion of the cylindrical shaft is provided in a portion that is disengaged from the transport unit, it is possible to avoid the transport state of the transport unit from being varied.

The transport device according to the present invention is rotatably provided, and transports the transported medium between a transport roller having a transport unit that transports the transported medium, a driving device that drives the transport roller, and the transport roller. And a driven roller that rotates while being held, wherein the transport roller is used as the transport roller.
According to the present invention, since the transporting medium can be transported by driving the transport roller capable of maintaining the intended transport accuracy, it is possible to provide a transport device with high transport accuracy.

A printing apparatus according to the present invention includes a conveyance unit that conveys a medium to be conveyed, and a printing unit that performs a printing process on the recording medium conveyed by the conveyance device. A transport device is used.
According to the present invention, printing can be performed while transporting a recording medium using a transport apparatus having high transport accuracy, and therefore high-precision printing is possible.

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. It is a schematic block diagram of a conveyance roller mechanism. (A), (b) is a top view which shows the metal plate as a base material of a roller main body. (A)-(c) is process drawing for demonstrating the press work of a metal plate. (A)-(c) is process drawing for demonstrating the press work of a metal plate. It is a perspective view of the roller main body which concerns on 1st Embodiment. It is a figure for demonstrating the shape of the joint of the roller main body which concerns on 1st Embodiment. It is the expanded sectional side view of a joint. (A)-(c) is a figure which shows the formation process of the high friction layer to a roller main body. It is a schematic block diagram of the coating booth for forming a high friction layer. It is the principal part enlarged view of the joint of a roller main body, and its vicinity. (A), (b) is a top view which shows the metal plate as a base material of a roller main body. (A) is a perspective view of a roller main body, (b) is explanatory drawing of the shape of the joint of a roller main body, (b) is a sectional side view of a joint. (A), (b) is a top view which shows the metal plate as a base material of a roller main body. (A) is a perspective view of a roller main body, (b) is a sectional side view of a joint. (A) is explanatory drawing of the shape of the joint of a roller main body, (b) is a sectional side view of a joint. (A) is a principal part perspective view of a roller main body, (b) is a principal part sectional 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) is a principal part perspective view of a roller main body, (b) is a side view. (A)-(c) is a principal part top view of the metal plate which shows an expansion | deployment engaging part.

  Hereinafter, the present invention will be described in detail 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. First, with reference to FIG. 1, FIG. 2, the printing apparatus provided with the conveyance roller which concerns on this invention is demonstrated.

  FIG. 1 is a side sectional view of a printing apparatus (inkjet printer) provided with a conveyance unit according to the present invention, FIG. 2A is a plan view of a conveyance unit portion of the printing apparatus, and FIG. It is a side view of a drive system.

  FIG. 1 shows an ink jet printer 1 which is an embodiment of a printing apparatus of the present invention. The ink jet printer 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 discharge unit 7 formed on the front side of the printer main body 3. Is.

  A paper feed tray 11 is provided in the paper feed unit 5, and a plurality of sheets (recording media) P are stacked on the paper feed tray 11. Here, as the paper P, for example, plain paper, coated paper, OHP (overhead projector) sheet, glossy paper, glossy film, or the like is used. 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 forward.

  The fed paper P reaches a transport roller mechanism 19 including a transport roller 15 disposed on the lower side and a driven roller 17 disposed on the upper side. The conveyance roller 15 becomes one Embodiment of the conveyance roller of this invention so that it may mention later. Further, the transport unit 10 is configured by the transport roller 15, the driven roller 17, and a driving device that rotationally drives the transport roller 15. The paper P reaching the transport roller mechanism 19 is subjected to a precise and accurate transport (paper feed) operation accompanying the printing process by the rotational drive of the transport roller 15, and the print head located on the downstream side of the transport roller mechanism 19 (Printing section) 21 is conveyed.

  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 feed direction (paper P transport direction). A platen 24 is disposed at a position facing the print head 21, and the platen 24 is constituted by 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. Specifically, the top surface of the diamond rib 25 functions as a support surface. . Note that the printing process (printing process) by the print head 21 is controlled by the control unit CONT.

  The distance between the print head 21 and the diamond rib 25 can be adjusted according to the thickness of the paper P, so that the paper P can pass through the top surface of the diamond rib 25 and be high quality. It is supposed to be printed. The paper P printed by the print head 21 is sequentially discharged by a paper discharge roller 29 provided in the paper discharge unit 7. The paper discharge roller mechanism 27 includes a paper discharge roller 29 disposed on the lower side and a paper discharge jagged roller 31 disposed on the upper side. It comes to discharge.

  Here, the relationship between the drive system of the transport roller 15 and the paper discharge roller 29 and the drive speed of both the rollers 15 and 29 in the transport roller mechanism 19 and the paper discharge roller mechanism 27 will be described. As shown in FIGS. 2A and 2B, the printer body 3 is provided with a transport motor (drive device) 32 that is driven under the control of the control unit CONT.

  A pinion 33 is provided on the drive shaft of the transport motor 32, 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. ing. Under such a configuration, the transport motor 32 is a driving device 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 29 as shown in FIG. Under such a configuration, the transport roller 15 of the transport roller mechanism 19 and the paper discharge roller 29 of the paper discharge roller mechanism 27 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 29 is set to be faster than the rotation speed of the transport roller 15 by adjusting the gear ratio of each gear described above. Accordingly, the paper discharge speed of the paper discharge roller mechanism 27 is faster than the transport speed of the transport roller mechanism 19 by an increase rate s.

  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 27. Therefore, when the transport roller mechanism 19 and the paper discharge roller mechanism 27 both hold the paper P, the paper transport speed is independent of the paper discharge speed of the paper discharge roller mechanism 27 and is transported by the transport roller mechanism 19. It is specified by speed.

  Next, the conveyance roller mechanism 19 provided with the conveyance roller 15 according to the present invention will be described. FIG. 3 is a diagram illustrating a schematic configuration of the transport roller mechanism 19 including the transport roller 15 and the driven roller 17.

  The transport roller 15 includes a roller main body 16 formed into a cylindrical shape by pressing a metal plate such as a galvanized steel plate or a stainless steel plate, and a high friction layer 50 provided on the surface of the roller main body 16. Is. Here, the roller body 16 is an embodiment of the cylindrical shaft in the present invention.

  Further, the both ends of the transport roller 15 are rotatably held by the bearing 70. In particular, an end portion on the side connected to the inner gear 39 and the transport driving gear 35 described above is an engaging portion (not shown) for engaging and connecting to the inner gear 39 and the transport driving gear 35 in a non-rotatable manner. ) Is formed. In addition, since it connects with various connection components, the engaging part of various forms can be formed in the conveyance roller 15 so that it may mention later. Moreover, the high friction layer 50 is selectively formed in the center part except the both ends of the roller main body 16 in this example.

  The driven roller 17 is configured by a plurality of (for example, six) rollers 17 a being arranged coaxially, and is disposed at a position where the driven roller 17 faces the high friction layer 50 of the transport roller 15 and abuts on the high friction layer 50. It is a thing. 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 roller body (cylindrical shaft) 16 is formed in a cylindrical shape by pressing a metal plate and bringing a pair of opposed end portions (end surfaces) into close proximity or abutting each other. . Therefore, the roller main body 16 has a joint formed between a pair of end portions. Usually, a gap is formed at the joint by slightly separating the pair of end portions (end surfaces). Has been.

Next, the detailed structure and manufacturing method of the conveyance roller 15 (roller main body 16) are demonstrated using FIGS.
To manufacture the transport roller 15, first, as shown in FIG. 4A, a rectangular or strip-shaped large metal plate (first metal plate) 65 is prepared. As the large metal plate 65, for example, a galvanized steel plate having a thickness of about 1 mm is used.

  Subsequently, the large metal plate 65 is cut by pressing to form a metal plate 60 having a shape corresponding to the roller main body 16 as shown in FIG. 4B. The metal plate 60 serves as a base material for the roller body 16. The metal plate 60 is provided with, for example, three regions 60a to 60c. A first region 60a is provided at the center in the vertical direction in the figure. The second regions 60b and 60c are provided at both ends of the first region 60a in the vertical direction so as to sandwich the first region 60a in the vertical direction in the drawing.

  The first region 60a, the second region 60b, and the third region 60c have the same horizontal dimension (L1, L2, L3) in the drawing. The second region 60b is provided with a predetermined dimension L5 shifted from the first region 60a, for example, in the left direction in the figure. The first production region 60c is provided with a predetermined dimension L4 shifted from the first region 60c, for example, in the right direction in the figure. In the present embodiment, the predetermined dimension L4 and the predetermined dimension L5 are equal. Therefore, the second region 60b and the second production region 60c are provided so as to be shifted to the left and right by half the dimension of the first region 60a in the left-right direction in the drawing. Of course, the predetermined dimension L4 and the predetermined dimension L5 may be set to different dimensions.

  For example, as shown in FIG. 4C, the metal plate 60 has a configuration in which the second region 60b and the third region 60c are shifted from the first region 60a in the same direction in the left-right direction in the drawing. It does not matter. FIG. 4C shows a state shifted to the left in the drawing as an example, but it may of course be shifted to the right in the drawing.

  Returning to FIG. 4B, the vertical dimension H1 in the drawing of the first region 60a is the sum of the same dimension H2 of the second region 60b and the same dimension H3 of the third region 60c. It is preferable that it is formed so as to be approximately equal to.

  Further, when such a metal plate 60 is formed, when a pair of long sides (end portions 61a and 61b) are brought close to each other by press working, a gap formed in a joint formed therebetween, that is, mutually The dimensions and the like are designed so that the distance between the opposing end portions (end faces) has a relationship as described later between the respective parts, and press working is performed based on this.

  Next, the metal plate 60 is pressed into a cylindrical shape (pipe shape) as shown in the pressing process diagrams of FIGS. 5 (a) to 5 (c) and FIGS. 6 (a) to 6 (c). Side) end portions 61a and 61b are brought close to or in contact with each other. In the press working process shown in FIGS. 5A to 5C and FIGS. 6A to 6C, it is assumed that the metal plate 60 is rectangular in order to make the process contents easy to understand. explain. When performing the following pressing process, for example, the first region 60a, the second region 60b, and the third region 60c of the metal plate 60 may be performed individually or collectively.

  That is, first, the metal plate 60 is pressed by the male mold 101 and the female mold 102 shown in FIG. 5A, and both side portions 62a and 62b of the metal plate 60 are formed in an arc shape (preferably approximately 1/4 arc). Bend. In FIG. 5A, in order to make each member easy to understand, the metal plate 60, the male mold 101, and the female mold 102 are shown with an interval between them, but this interval is actually The metal plate 60 and the male mold 101 and the female mold 102 are almost in close contact with each other at their contact portions. The same applies to FIGS. 5B and 5C and FIGS. 6A to 6C described later.

  Subsequently, the central portion in the width direction (bending direction) of the metal plate 60 obtained in FIG. 5A is pressed with the male mold 103 and the female mold 104 shown in FIG. It is preferably bent to approximately 1/4 arc). Next, as shown in FIG. 5C, the core mold 105 is disposed inside the metal plate 60 obtained in FIG. 5B, and the upper mold 106 and the lower mold 107 shown in FIG. 6A to 6C, the end surfaces (end portions) 61a and 61b of the both side portions 62a and 62b of the metal plate 60 are brought close to each other.

  Here, the outer diameter of the core mold 105 shown in FIG. 5C and FIGS. 6A to 6C is equal to the inner diameter of the cylindrical hollow pipe to be formed. The radius of the press surface 106c of the upper die 106 and the radius of the press surface 107a of the lower die 107 are equal to the radius of the outer diameter of the hollow pipe to be formed. Further, as shown in FIGS. 6A to 6C, the upper mold 106 is a pair of left and right split molds, and the split molds 106a and 106b are configured to be able to move up and down independently.

  That is, from the state shown in FIG. 5 (c), the right split mold 106a is lowered relative to the lower mold 107 as shown in FIG. 6 (a). ), One side of the metal plate 60 is pressed and bent into a substantially semicircular shape. The lower mold 107 may also be a pair of left and right split molds as in the upper mold 106 (see the split surface 107b), and the lower mold on the same side may be raised during the process shown in FIG.

  Next, as shown in FIG. 6 (b), the split mold 106a is lowered slightly (so that the end 61a on one side and the end 61b on the other side can be brought close to each other) and the other side The lower mold 106b is lowered and the other side of the metal plate 60 is pressed and bent into a substantially semicircular shape.

  Thereafter, as shown in FIG. 6C, both the core mold 105 and the upper mold 106 (split molds 106a and 106b) are lowered to form a cylindrical hollow pipe (roller body 16). In this state, the left and right end portions 61a and 61b are sufficiently close to each other through a slight gap or are in partial contact with each other. That is, in this cylindrical hollow pipe, both ends 61a and 61b of the metal plate 60 which is a base material are close to or in contact with each other, so that a joint is formed between these both ends 61a and 61b. ing. Therefore, the joints usually have a gap because the both end portions 61a and 61b are slightly separated from each other.

  In addition, when performing the press work process shown in FIGS. 5A to 5C and FIGS. 6A to 6C using the metal plate 60 having the configuration shown in FIG. 4C, for example, the first region 60a. When the second region 60b and the third region 60c are separately performed, the second region 60b and the third region 60c can be performed in one step using a common mold member.

  Next, in this embodiment, in order to increase the roundness of the formed hollow pipe (roller body 16) and reduce the runout, conventionally known centerless polishing is performed, and the outer periphery of the hollow pipe (roller body 16) described above is performed. Polish the surface. Then, this hollow pipe has a roundness better than that before the centerless polishing process, and the roller body 16 having a small runout, that is, the cylindrical shaft according to the present invention. Further, in the roller body (cylindrical shaft) 16, the gap between the both end portions 61a and 61b is narrowed as shown in FIG. An eye 80 is formed.

  In the press working and centerless polishing described above, it is preferable that the gap between both end portions 61a and 61b of the metal plate 60 is eliminated, that is, the both end portions 61a and 61b are in contact with each other. However, it is very difficult to completely eliminate the gap while improving the roundness and the amount of deflection of the hollow pipe (roller body 16) to be obtained, so that a certain degree of gap is formed at present. Become.

  As shown in FIGS. 7 and 8, the joint 80 of the roller body 16 includes a joint portion 80a corresponding to the first region 60a shown in FIG. 4B, a joint portion 80b corresponding to the second region 60b, and In addition, the connecting portion 80c corresponding to the third region 60c is provided. The connecting portions 80 a to 80 c are formed in a straight line so as to be parallel to the central axis 16 b of the roller body 16, for example. Among these, the connection part 80a is a 1st connection part in this invention. The connecting portions 80b and 80c are the second connecting portions in the present invention.

  The connecting portion 80a and the connecting portion 80b are connected by a connecting portion 80d. The connecting portion 80a and the connecting portion 80c are connected by a connecting portion 80e. The connecting portions 80 d and 80 e are formed along the circumferential direction of the roller body 16.

  The connecting portion 80a, which is the first connecting portion, and the connecting portions 80b and 80c, which are the second connecting portions, are respectively formed on the opposite sides of the roller body 16 with the central axis 16b interposed therebetween. When the metal plate 60 is formed, the second region 60b and the third region 60c are shifted from each other by the same dimensions L4 and L5 with respect to the first region 60a. As a result of the press work, the joint portion 80a and the joint portion 80b are formed. And 80c are the positional relationship.

  Therefore, when the metal plate 60 is formed, if the second region 60b and the third region 60c are shifted by different dimensions with respect to the first region 60a, the connecting portion 80b and the connecting portion 80c are formed on the roller body 16. It is formed at a position shifted in the circumferential direction. Of course, such a configuration may be adopted as long as it is arranged on the opposite side of the connecting portion 80a across the central axis 16a.

  For example, the connecting portion 80 a, the connecting portion 80 b, and the connecting portion 80 c may be formed at positions shifted by 120 °, for example, in the circumferential direction of the roller body 16. In this case, when the metal plate 60 is formed, the second region 60b and the third region 60c are separated from the first region 60a by a third dimension of the first region 60a (left and right in FIG. 4B). What is necessary is just to form so that only the direction dimension) may shift | deviate.

  Further, the connecting portion 80a is formed at the central portion of the roller body 16 in the central axis direction, and the connecting portions 80b and 80c are divided and formed so as to sandwich the connecting portion 80a. When the metal plate 60 is formed, if the dimension H1 of the first region 60a is formed to be approximately equal to the sum of the dimension H2 of the second region 60b and the dimension H3 of the third region 60c, the first joint portion The dimension in the central axis direction (the dimension in the central axis direction of the joint portion 80a) is substantially equal to the dimension in the central axis direction of the second joint portion (the total dimension of the joint portions 80b and 80b).

  In the present embodiment, the connecting portion 80a that is the first connecting portion and the connecting portions 80b and 80c that are the second connecting portions are formed on the opposite sides of the roller body 16 with the center axis 16b interposed therebetween, respectively. The influence of the relaxation of the residual stress in the pressing process is offset between the connecting portion 80a and the connecting portions 80b and 80c. For this reason, the shape change of the roller main body 16 is suppressed.

  The joint 80 is relatively wide on the outer peripheral surface side of the roller body 16 as shown in FIG. 9 because the outer peripheral surface and the inner peripheral surface of the metal plate 60 have the same dimension (width). It is relatively narrow on the inner peripheral surface side. This configuration is substantially the same for the connecting portions 80a to 80c. That is, the distance d1 between the pair of end portions 61a and 61b on the outer peripheral surface side of the roller body 16 is larger than the distance d2 on the inner peripheral surface side. Specifically, in this embodiment, the distance d1 (= d4) on the outer peripheral surface side is about 20 μm, and the distance d2 on the inner peripheral surface side is about 8 μm.

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

  That is, in the present invention, alumina particles (inorganic particles) having an average particle diameter (center diameter) larger than the distance d1 (30 μm) on the outer peripheral surface side of the joint 80 are used. In particular, the particle size distribution (particle size range) includes particles that are smaller than the distance d1 on the outer peripheral surface side of the joint 80 and larger than the distance d2 (10 μm) on the inner peripheral surface side. It is preferable. Furthermore, the minimum particle size in the particle size distribution is preferably larger than the shortest distance between the pair of end portions 61a and 61b in the joint 80, for example, the distance d2 on the inner peripheral surface side.

  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.

  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 over the entire length of the roller body 16, for example, by masking both ends with a tape or the like, it is performed only on the central portion excluding the both ends as shown in FIG. That is, only the region corresponding to the central portion of the transport roller 15 composed of the roller body 16 that corresponds to at least the region in contact with the transported paper (medium) P, for example, the region where the connecting portion 80a is formed is selected. Thus, the resin film 51 is formed.

  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 film thickness of, for example, about 10 μm to 30 μm in consideration of the powder diameter of the alumina particles. 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. 11 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.

  In addition, a corona gun 93 is disposed on the coating booth 90, and the corona gun 93 moves on the shaft 94 in the left-right direction in FIG. Further, an exhaust mechanism 90 a 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 94 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 about 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 1011Ω.

  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. 10, alumina particles 95 having substantially zero potential are blown out from above, and the alumina particles 95 are naturally dropped in the vertical direction by their own weight.

  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 rotates slowly around its axis, so that the alumina particles 95 are dispersed almost uniformly on the outer peripheral surface of the roller body 16.

  Accordingly, the alumina particles 95 are uniformly attached to the surface of the resin film 51 that is not particularly masked. As a result, the roller main body 16 has alumina in the resin film 51 at the center as shown in FIG. The particles (inorganic particles) 95 are dispersed and exposed. 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.

  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. Thus, as shown in FIG. 10C, the high friction layer 50 is formed in which the alumina particles (inorganic particles) 95 are dispersed and exposed in the resin film 51, and the transport roller 15 according to the present invention is obtained. In the present embodiment, the friction layer 50 is formed only in the region where the connecting portion 80a is formed, and further, the connecting portions 80b and 80c and the connecting portions 80d and 80e are formed at positions away from the friction layer 50. For this reason, the conveyance state by the friction layer 50 does not vary in the entire friction layer 50.

  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.

  When the high friction layer 50 is formed in this way, a groove due to the gap between the end portions (end surfaces) 61a and 61b of the metal plate 60 is formed particularly at the joint 80 shown in FIGS. Instead, the gap between the end portions 61 a and 61 b is mainly filled with the alumina particles 95.

  That is, since the alumina particles 95 having an average particle diameter larger than the distance d1 on the outer peripheral surface side of the joint 80 are used, most of the alumina particles 95 do not enter the joint 80. As shown in FIG. 11, it adheres to the outer peripheral surface of the roller body 16 through a resin film 51. Accordingly, although the gap 80 is formed between the end portions 61a and 61b of the metal plate 60 in the joint 80, the alumina particles 95 cover the gap, so that a groove due to the gap is substantially formed. No longer formed.

  Further, the alumina particle 95 has a particle size distribution (particle size) including particles 95a that are smaller than the distance d1 on the outer peripheral surface side of the joint 80 and larger than the distance d2 (10 μm) on the inner peripheral surface side. Since the particles 95a enter the gap formed in the joint 80 and stay there, the groove due to the joint 80 is not reliably formed.

  In addition, even when a force is applied to the roller body 16 (conveying roller 15) in the direction of narrowing the gap, the alumina particles 95a that have entered here resist this force. The deformation of 15) can be suppressed. Therefore, in the transport roller mechanism 19 including the transport roller 15, transport unevenness due to deformation of the transport roller 15 is prevented.

  In the roller main body (cylindrical shaft) 16 constituting such a transport roller 15, the joint 80 formed between the pair of end portions 61a and 61b is, as shown in FIG. Since the distance d3 between the pair of end portions facing each other in 83b is longer than the distance d4 between the pair of end portions facing each other in the first linear portion 83a, the shape as a cylindrical hollow pipe is formed. And accuracy with respect to dimensions.

  That is, as shown by the solid line in FIG. 9, the dimension t2 of the portion where the tip side of the convex piece 88 forming the second straight line portion 83b floats outside is compared with the dimension t1 shown by the two-dot chain line in FIG. As a result, the formation of a step in the second straight portion 83b can be suppressed.

  In addition, by suppressing the formation of a step in the second linear portion 83b in this way, it is possible to suppress deformation or the like of the roller body 16 due to the step and to increase the accuracy of the shape and dimensions.

  Further, since the first straight portion 83a and the second straight portion 83b in the bent portion 81 are formed substantially parallel to the central axis 16a of the roller body 16, when the metal plate 60 serving as a base material is pressed, The pair of end portions 61a and 61b facing each other over the entire length of the joint 80 can be brought close to each other or brought into contact with each other with relatively high accuracy.

  Further, since the intersecting portion 82 in the bent portion 81 extends in a direction substantially orthogonal to the central axis 16a of the roller body 16, it faces the intersecting portion 82 when the metal plate 60 is pressed. It is possible to make the ends close to each other approach or contact each other with relatively high accuracy.

  And the conveyance roller 15 formed by forming the high friction layer 50 on such a roller main body 16 uses a roller main body (cylindrical shaft) 16 formed by pressing a metal plate 60 into a cylindrical shape. Compared with the case of using a real round bar, the cost and weight can be reduced. Moreover, by providing the high friction layer 50 containing alumina particles 95 (inorganic particles), a good conveying force is exhibited. Furthermore, since the roller body 16 has higher accuracy with respect to the shape and dimensions as described above, the conveyance unevenness due to insufficient accuracy is also suppressed.

  In general, both ends of the roller main body 16 (conveying roller 15) are parts for attaching a connecting component of a driving system such as a gear, and the center of the roller main body 16 is in direct contact with the paper P (recording medium). Part. Therefore, in the present embodiment, the high friction layer 50 described above is provided in the central portion excluding both ends of the roller body 16, that is, in the region in contact with the paper (medium) P, so that the conveyance performance of the paper P is reduced. In addition, the material cost of the high friction layer 50 can be minimized.

  As described above, according to the present embodiment, since the joint portion 80a constituting the joint 80 and the joint portions 80b and 80c are provided on the opposite side across the central axis 16a of the roller body 16, the residual portion The influence of stress relaxation is offset between the connecting portion 80a and the connecting portions 80b and 80c. Thereby, the shape change of the roller main body 16 can be suppressed, and the roller main body 16 having a stable shape can be provided.

  Moreover, according to this embodiment, since the paper P which is a to-be-conveyed medium can be conveyed using the roller main body 16 with a stable shape, the conveyance roller 15 capable of maintaining the intended conveyance accuracy is provided. Can be provided.

  Furthermore, according to this embodiment, since the paper P is transported by driving the transport roller 15 capable of maintaining the intended transport accuracy, it is possible to provide the transport unit 10 with high transport accuracy.

  In addition, according to the present embodiment, printing can be performed while transporting the paper P using the transport unit 10 with high transport accuracy, and thus the inkjet printer 1 capable of high-precision printing can be provided.

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

  For example, in the above-described embodiment, an example in which a joint formed between a pair of end portions is formed in a straight line has been described. However, the present invention is not limited thereto, and for example, a joint formed between a pair of end portions. A configuration in which a bent portion is formed in the eyes may be used.

  In this case, first, as shown in FIG. 13A, a rectangular or strip-shaped large metal plate (first metal plate) 65 is prepared. Subsequently, the large metal plate 65 is subjected to a cutting process by pressing, and as shown in FIG. 13B, a long and substantially rectangular metal plate (second shape) having a size corresponding to the roller body 16 described above. (Metal plate) 60, that is, the metal plate 60 that becomes the base material of the roller body 16 is formed.

  However, when the large metal plate 65 is pressed, a pair of opposing long sides are formed at the joint formed between the pair of end portions at the same time as the above-described cutting process. A rectangular wave-shaped concavo-convex portion 110 is formed at the end portions 61a and 61b.

  Next, as in the first embodiment, the metal plate 60 is pressed into a cylindrical shape (pipe shape) as shown in the pressing process diagrams of FIGS. 5 (a) to 5 (c) and FIGS. 6 (a) to 6 (c). After processing, the end portions 61a and 61b on both sides (long side) are brought close to each other or brought into contact with each other.

  Similarly to the first embodiment, centerless polishing is performed in order to increase the roundness of the hollow pipe (roller body 16) formed by pressing and to reduce runout, and the hollow pipe (roller body 16) The outer peripheral surface is polished.

  As shown in FIG. 14A, the joint 80 formed in this way is formed in a straight line so that the joint portions 80 a to 80 c are parallel to the central axis 16 b of the roller body 16, for example. . Among these, the connection part 80a is a 1st connection part in this invention. The connecting portions 80b and 80c are the second connecting portions in the present invention. The connecting portion 80a and the connecting portion 80b are connected by a connecting portion 80d. The connecting portion 80a and the connecting portion 80c are connected by a connecting portion 80e. The connecting portions 80 d and 80 e are formed along the circumferential direction of the roller body 16.

  Further, as shown in FIG. 14B, the joint 80 includes a plurality of intersecting portions 82 that intersect the central axis 16 a of the roller body (cylindrical shaft) 16 and one of a pair of adjacent intersecting portions 82 and 82. The first linear portion 83a connecting the end portions on the side and the second linear portion 83b connecting the end portions on the other side.

Here, the first straight portion 83a and the second straight portion 83b are formed so as to be substantially parallel to the central axis 16a of the roller body 16, and the intersecting portion 82 is orthogonal to the first straight portion 83a and the second straight portion 83b. That is, it is formed so as to be substantially orthogonal to the central axis of the roller body 16.
Further, the second straight portion 83b is formed shorter than the first straight portion 83a.

  In the roller body (cylindrical shaft) 16, a distance d3 between a pair of end portions facing each other particularly in the second linear portion 83b is set to be a distance d4 between a pair of end portions facing each other in the first linear portion 83a. Form long. Here, the distances d3 and d4 between the pair of end portions are the distances between the end portions in the gap formed on the outer peripheral surface of the roller body 16, as will be described later.

  In this way, the accuracy of the shape and dimensions of the roller main body 16 as the cylindrical hollow pipe can be further increased, and therefore, uneven conveyance due to deformation of the roller main body 16 and the like can be prevented. That is, in the metal plate which is a base material for forming such a roller main body 16, one end portion constituting the second straight portion 83b is between a pair of adjacent intersecting portions 82 and 82 and these end portions. It becomes the convex piece 88 which makes the 2nd linear part 83b which ties to the external shape.

  Therefore, when the metal plate is pressed to make the convex piece 88 close to the opposite end, the tip side of the convex piece 88 is circumferential as shown by a two-dot chain line in FIG. Without being sufficiently bent into a planar shape, it is in a state of being lifted by a dimension t1 with respect to the opposite end. As a result, a step is formed in the second straight portion 83b. Then, due to this step, the obtained roller main body 16 is likely to be deformed, and it is difficult to obtain good accuracy in terms of shape and dimensions.

  Therefore, the distance d3 between the end portions of the second straight line portion 83b is made longer than the distance d4 between the end portions of the first straight line portion 83a formed longer than the second straight line portion 83b. As a result, as shown by a solid line in FIG. 14C, the dimension t2 of the portion where the tip end side of the convex piece 88 floats outside becomes smaller (smaller) than the above-described t1, and this causes the second linear portion 83b to The formation of a step can be suppressed.

  In FIG. 14C, the dimension t2 is also shown large for easy understanding, but actually the dimension t2 is almost close to zero and there is no substantial step. That is, by suppressing the formation of a step in the second linear portion 83b in this way, it is possible to suppress deformation or the like of the roller body 16 due to the step and to increase the accuracy of the shape and dimensions.

Further, for example, the connecting portion 80a can be formed in a linear shape, and the connecting portions 80b and 80c can be formed in a rectangular wave shape.
In this case, first, as shown in FIG. 15 (a), a rectangular metal plate or strip-shaped large metal plate 65 is cut by pressing, and as shown in FIG. 15 (b), the roller body described above is cut. A metal plate 60 having an elongated rectangular plate shape having a size corresponding to 16, that is, a metal plate 60 serving as a base material of the roller body 16 is formed.

  However, when the large metal plate 65 is pressed, a pair of opposing long sides are formed at the joint formed between the pair of end portions at the same time as the above-described cutting process. The rectangular corrugated portions 110 are formed at both end portions of the end portions 61a and 61b in the length direction. Moreover, in each long side (end part 61a, 61b), the linear part 111 is formed between the uneven | corrugated | grooved parts 110 formed in the both ends, ie, a center part.

  Next, as in the first embodiment, the metal plate 60 is pressed into a cylindrical shape (pipe shape) as shown in the pressing process diagrams of FIGS. 5 (a) to 5 (c) and FIGS. 6 (a) to 6 (c). After processing, the end portions 61a and 61b on both sides (long side) are brought close to each other or brought into contact with each other. Similarly to the first embodiment, centerless polishing is performed in order to increase the roundness of the hollow pipe (roller body 16) formed by pressing and to reduce runout, and the hollow pipe (roller body 16) The outer peripheral surface is polished.

  As shown in FIG. 16 (a), the joint 80 formed in this way is fitted with the concave and convex portion 110 shown in FIG. 15 (b). A wavy both-end bent portion 85 is formed. Further, a central straight portion 84 is formed between the bent portions 85 at both ends because the straight portion 111 shown in FIG. The central straight portion 84 is formed to include a region corresponding to a high friction layer to be described later, that is, a region that forms at least the high friction layer.

  In addition, the joint 80 is formed in the linear form so that the center linear part 84 and the both-end bending part 85 may be parallel to the central axis 16b of the roller main body 16, for example like the said embodiment. Among these, the center straight part 84 is a 1st connection part in this invention. The both ends bent portion 85 is a second connecting portion in the present invention. The central straight portion 84 and the bent portions 85 are connected by connecting portions 84t. The connecting portion 84t is formed along the circumferential direction of the roller body 6.

  This joint 80 has a pair of ends as shown in FIG. 16B, for example, in the central straight portion 84 because the outer peripheral surface and the inner peripheral surface of the metal plate 60 are the same size (width). The distance between the portions (end surfaces) 61a and 61b is relatively wide on the outer peripheral surface side of the roller body 16 and relatively narrow on the inner peripheral surface side.

  That is, the distance d1 between the pair of end portions 61a and 61b on the outer peripheral surface side of the roller body 16 is larger than the distance d2 on the inner peripheral surface side. Specifically, in this embodiment, the distance d1 on the outer peripheral surface side is 30 μm, and the distance d2 on the inner peripheral surface side is 10 μm.

  Further, as shown in FIG. 17A, the both-end bent portion 85 includes a connecting straight portion 87 (first straight portion 87a, second straight portion 87b) substantially parallel to the central axis 16a of the roller body 16, and It consists of a linear intersection 86 that is orthogonal to this and therefore substantially orthogonal to the central axis 16a.

  That is, the bent portions 85 formed at both ends of the joint 80 include a plurality of straight intersecting portions 86, a first straight portion 87a connecting the ends on one side of the intersecting portions 86, and the other And a second straight line portion 87b connecting the end portions on the side.

  Here, the first straight portion 87 a of the connecting straight portions 87 is formed on the same straight line as the central straight portion 84. The first straight portion 87 a is formed longer than the other second straight portion 87 b of the connecting straight portions 87.

  And in this embodiment, in this both-ends bending part 85, the 2nd linear part 87b side used as the front-end | tip part of the convex piece 88 formed of a pair of crossing parts 86 and 86 and the 2nd linear part 87b mutually A distance d7 between a pair of opposed end portions is formed longer than a distance d6 (= d1) between a pair of opposed end portions in the central linear portion 84.

  Further, the distance d7 between the end portions of the second linear portion 87b is longer than the distance d8 between the pair of end portions facing each other in the first linear portion 87a. Here, it is preferable that the distance d8 between the end portions in the first straight line portion 87a is equal to or longer than the distance d6 between the end portions in the central straight line portion 84.

  The distances d6, d7, d8 between the pair of end portions described above are all the distances between the end portions in the gap formed on the outer peripheral surface of the roller body 16.

  Specifically, in the present embodiment, the distance d6 (= d1) in the central straight portion 84 is 30 μm as described above, whereas the distance d7 in the second straight portion 87b is longer than 30 μm, for example, 40 μm or more. Is formed.

  Since the distance d7 is formed longer than the distance d6 (= d1) as described above, the roller body (cylindrical shaft) 16 has higher accuracy with respect to the shape and dimensions of the cylindrical hollow pipe. Yes.

  That is, in the metal plate 60 serving as a base material for forming such a roller body 16, one end constituting the second linear portion 87b is a pair of adjacent intersections 86, 86 and these end portions. It becomes the convex piece 88 which makes the external shape the 2nd linear part 87b which connects between. Therefore, when the metal plate 60 is pressed to make the convex piece 88 close to the opposite end, the tip side of the convex piece 88 is circular as shown by a two-dot chain line in FIG. It is not bent sufficiently in the shape of the peripheral surface, and is in a state of being lifted by a dimension t1 with respect to the opposite end. As a result, a step is formed in the second straight portion 87b. Then, due to this step, the obtained roller main body 16 is likely to be deformed, and it is difficult to obtain good accuracy in terms of shape and dimensions.

  Therefore, the distance d7 between the end portions of the second straight line portion 87b is made longer than the distance d6 between the end portions of the central straight line portion 84 formed longer than the second straight line portion 87b. As a result, as shown by a solid line in FIG. 17B, the dimension t2 of the floating portion of the tip end side of the convex piece 88 is smaller (smaller) than the aforementioned t1. Therefore, it is possible to suppress the formation of a step in the second straight portion 87b.

  In FIG. 17B, the dimension t2 is also shown large for easy understanding, but actually, the dimension t2 is almost close to zero and there is no substantial step. That is, by suppressing the formation of a step in the second linear portion 87b as described above, it is possible to suppress deformation or the like of the roller body 16 due to the step and to increase the accuracy of the shape and dimensions.

  Further, when the distance d8 between the end portions in the first straight line portion 87a is formed to be the same as the distance d6 between the end portions in the central straight line portion 84, both side ends of the metal plate 60 constituting the first straight line portion 87a and Both side ends constituting the central straight line portion 84 can be aligned with the same line. Therefore, the press working of the metal plate 60 can be facilitated. Therefore, by comprising in this way, the precision about the shape and dimension of the roller main body 16 obtained can be made more favorable, and a deformation | transformation etc. can be suppressed.

  On the other hand, when the distance d8 between the end portions in the first straight line portion 87a is formed longer than the distance d6 between the end portions in the central straight line portion 84, as in the case described with reference to FIG. The size of the floating part of the protruding piece 89 having the one straight part 87a side as the tip is reduced (small). Accordingly, it is possible to suppress the formation of a step in the first straight portion 87a. When the roller body 16 serving as the cylindrical shaft is formed in this way, the high friction layer 50 is formed on the surface of the roller body 16 as shown in FIG.

  Incidentally, the resin film is formed by spraying the resin particles except for the bent portions 85 (both ends) corresponding to the formation region of the high friction layer 50 shown in FIG. 3 as shown in FIG. Only in the center. That is, the resin film 51 is selectively formed only in the central portion of the transport roller 15 composed of the roller body 16 that is at least the central portion that is in contact with the paper (medium) P to be transported, that is, the region corresponding to the central straight portion 84. To do.

  In the roller main body (cylindrical shaft) 16 constituting such a transport roller 15, the joint 80 formed between the pair of end portions 61a and 61b is linear as shown in FIG. Since the central straight portion 84 is formed by the bent portions 85 formed on both sides of the central straight portion 84, the central straight portion 84 is not fitted by unevenness. Therefore, compared to the case where a fitting portion with unevenness is formed over the entire length of the joint 80, the roller body 16 is less likely to be distorted or twisted, and the shape and dimensions such as roundness and runout have good accuracy. It becomes easy to obtain.

  Further, as shown in FIG. 17A, the distance d7 between a pair of ends facing each other in the second straight line portion 87b in the both-end bent portion 85 is defined as a pair of end portions facing each other in the central straight line portion 84. Since it is formed longer than the distance d6, the roller body (cylindrical shaft) 16 has higher accuracy with respect to the shape and dimensions of the cylindrical hollow pipe.

  That is, as indicated by a solid line in FIG. 17B, the dimension t2 of the amount of the tip side of the convex piece 88 forming the second straight line portion 87b floating outward is indicated by a two-dot chain line in FIG. It can be made smaller (smaller) than the dimension t1 shown. As a result, the formation of a step in the second straight line portion 87b can be suppressed.

  In addition, by suppressing the formation of the step in the second linear portion 87b as described above, it is possible to suppress deformation or the like of the roller body 16 due to the step, and to improve the accuracy of the shape and dimensions.

  Further, since the connecting straight line portions 87 (first straight line portion 87a, second straight line portion 87b) in the both-end bent portion 85 are formed substantially parallel to the central axis 16a of the roller body 16, the connecting straight line portions 87 are It becomes substantially parallel to the central straight portion 84. Therefore, when the metal plate 60 serving as the base material is pressed, the pair of opposed end portions 61a and 61b can be brought into close contact with each other or brought into contact with each other over the entire length of the joint 80.

  Further, since the first straight portion 87a in the connecting straight portion 87 is formed on the same straight line as the central straight portion 84, this also covers the entire length of the joint when the metal plate 60 is pressed. Thus, the pair of opposed end portions can be brought close to or brought into contact with each other with relatively high accuracy.

  Moreover, since the 1st linear part 87a in the connection linear part 87 is formed longer than the other 2nd linear part 87b, this also opposes over the full length of a joint, when a metal plate is pressed. The pair of end portions can be brought close to or brought into contact with each other with relatively high accuracy.

  Further, since the distance d7 between the end portions of the second straight portion 87b of the connecting straight portion 87 is formed to be longer than the distance d8 between the end portions of the first straight portion 87a, particularly the end portion of the first straight portion 87a. Even if the distance d8 between them is the same as the distance d6 between the ends of the central straight portion 84 or longer than this, in any case, deformation or the like is caused in the roller body 16 obtained as described above. It can be suppressed from occurring.

  In addition, since the intersecting portion 86 of the both-end bent portion 85 extends in a direction substantially perpendicular to the central axis 16a of the roller body 16, when the metal plate 60 is pressed, The opposing end portions can be brought close to each other or brought into contact with each other with relatively high accuracy.

  Therefore, the roller main body 16 (conveyance roller 15) is a solid round bar by using the roller main body (cylindrical shaft) 16 formed by pressing the metal plate 60 into a cylindrical shape, as in the above embodiment. Compared to the case of using a material, the cost can be reduced and the weight can be reduced. Moreover, by providing the high friction layer 50 containing alumina particles 95 (inorganic particles), a good conveying force is exhibited. Furthermore, since the roller body 16 has higher accuracy with respect to the shape and dimensions as described above, the conveyance unevenness due to insufficient accuracy is also suppressed.

  In general, both ends of the roller main body 16 (conveying roller 15) are parts for attaching a connecting component of a driving system such as a gear, and the center of the roller main body 16 is in direct contact with the paper P (recording medium). Part. Accordingly, in the present embodiment, the high friction layer 50 is provided in the central straight portion 84 excluding the bent portions 85 at both ends of the roller body 16, that is, in a region in contact with the paper (medium) P. Without lowering, the material cost of the high friction layer 50 can be minimized.

Next, the engaging part formed in the both tip side of said roller main body 16 (conveyance roller 15) is demonstrated using FIGS.
Engaging portions for connecting to various connecting parts such as the transport drive gear 35 and the inner gear 39 shown in FIG. 2 are formed on one or both ends of the both ends of the roller body 16 (transport roller 15). It is possible.

  For example, as shown in FIGS. 18 (a) and 18 (b), on opposite positions of the roller body 16 composed of cylindrical pipes (hollow pipes), that is, on two formation surfaces that define the diameter of the roller body 16 The through holes 71a and 71a are formed, respectively. Then, an engagement hole (engagement portion) 71 including the pair of through holes 71a and 71a is 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. 19A and 19B, 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 as shown in FIG. 73a is formed. Thereby, as shown in FIG. 19B, the outer shape of the side surface of the end portion is formed in an apparent D shape.

  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. 20A and 20B, an engaging portion 74 having a groove 74 a and a D cut portion 74 b 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. 20 (a), the groove 74a 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. 20 (b), when the pair of bent pieces 74d and 74d are bent toward the central axis 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 component (not shown) such as a gear is engaged with the aforementioned groove 74a or engaged with the D-cut portion 74b so that the connecting component is idled with respect to the roller body 16 (conveying roller 15). It can be installed without. 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 part and fitting the convex portion into the opening 74c, it is possible to prevent idling.

  Further, as shown in FIGS. 21A and 21B, 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. 21A, 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 as a result, the outer shape of the end side surface is formed in an apparent D shape as shown in FIG. Is.

  Accordingly, by engaging a connecting part (not shown) such as a gear with the groove 75a or an apparently D-shaped portion formed by the opening 75b, the connecting part is moved to the roller. The main body 16 (conveying roller 15) can be attached without being idle. Also, in this engaging portion 75, similarly to the engaging portion 73 shown in FIGS. 20 (a) and 20 (b), by using the opening 75b, the connecting component is attached to the roller body 16 without being idle. be able to.

  In order to form the engagement holes 71 and the engagement portions 73, 74, and 75, the roller body 16 obtained by pressing the metal plate 60 is further subjected to cutting or the like. Can do. For example, with respect to the engaging portion 73 shown in FIGS. 20A and 20B, an apparently D-shaped engaging portion 73 is formed by cutting the end portion to form the opening 73a. Can do. Moreover, also about the engagement hole 71 shown to Fig.19 (a), (b), a pair of through-hole 71a, 71a can be made to oppose more favorably by drilling with respect to the roller main body 16. FIG. .

  However, when the roller body 16 is further processed in this way, the cost and time efficiency are reduced by adding a separate processing step only for the formation of the engaging portion. Therefore, before the roller body 16 is subjected to press processing, a deployment engagement portion that becomes an engagement portion is formed on the metal plate by another press processing, and when this metal plate is pressed to form the roller body 16. The engaging portion is preferably formed at the same time.

  Specifically, the large metal plate (first metal plate) 65 shown in FIGS. 4 (a) and 13 (a) is replaced with an uneven portion as shown in FIGS. 4 (b) and 13 (b). When the long and substantially rectangular metal plate (second metal plate) 60 having 110 is pressed, the long side of the obtained metal plate 60 is simultaneously processed from the large metal plate 65 to the small metal plate 60. At the end in the length direction, that is, at the outer ends of the bent portion 81 and the both end bent portions 85, a development 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. 22 (a), by processing a pair of through holes 71a and 71a at predetermined positions on the outer end portion of the concavo-convex portion 110 of the metal plate 60 and setting them as a deployment engaging portion 76a, By pressing the metal plate 60, the pair of through holes 71a and 71a described above can be made to face each other to form the engagement hole 71 shown in FIGS. 18 (a) and 18 (b).

  Further, as shown in FIG. 22 (b), the outer end portion of the concavo-convex portion 110 of the metal plate 60 is cut into a predetermined shape to form a deployment engagement portion 76b, whereby the metal plate 60 is pressed. The engaging portion 74 shown in FIGS. 20A and 20B can be formed. That is, the engaging portion 74 can be formed by forming a pair of notches (recessed portions) 74e and 74e and a pair of projecting pieces 74f and 74f as the deployment engaging portion 76b. However, in this example, after the metal plate 60 is pressed, it is necessary to fold the pair of projecting pieces 74f and 74f inward to form a bent piece 74d. It can be said that it is slightly insufficient to sufficiently increase.

  Therefore, as shown in FIG. 22 (c), the metal plate 60 is pressed by cutting the outer end portion of the concavo-convex portion 110 of the metal plate 60 into a predetermined shape to form a deployment engagement portion 76c. The engaging portion 75 shown in FIGS. 21A and 21B 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 metal plate 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. 21B 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.

Next, the operation of the ink jet printer (printing apparatus) 1 including the above-described transport roller mechanism 19 will be described with reference to FIGS. 1 and 2.
When the paper P fed by the paper feed roller 13 reaches the vicinity of the upstream side of the transport roller mechanism 19, the paper P is drawn between the transport roller 15 and the driven roller 17, and printing positioned downstream by driving both rollers. It is conveyed at a constant speed toward the lower side of the head 21.

  At this time, since the 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, between the transport roller 15 and the driven roller 17. The force for pinching the paper P is increased, and the transportability of the paper P is improved.

  In particular, since the transport roller 15 uses alumina particles having a predetermined particle diameter when forming the high friction layer 50, there is no groove due to the joint 80, and therefore, transport unevenness due to the groove is also prevented. Furthermore, since the roller body 16 has good accuracy with respect to shape and dimensions, this also prevents uneven conveyance. Therefore, the transport roller mechanism 19 performs more accurate and stable paper feeding (transport). When the printing start end of the paper P reaches a predetermined printing position directly below the print head (printing unit) 21, printing is started.

  Thereafter, when the leading edge of the paper P reaches the paper discharge roller mechanism 27, the paper discharge operation is started. Since the conveyance speed of the paper discharge roller mechanism 27 is set to be higher 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 27 both hold the paper P, the paper transport speed is defined by the transport speed of the transport roller mechanism 19 as described above. Therefore, even when the paper discharge roller mechanism 27 and the transport roller mechanism 19 simultaneously perform paper discharge and transport in this way, the paper transport speed is defined by the transport speed of the transport roller mechanism 19, so Accurate and stable paper feeding (conveyance) can be achieved.

  As described above, in the transport roller 15 of the present embodiment, a solid round bar is obtained by using the roller body (cylindrical shaft) 16 in which the metal plate 60 is pressed into a cylindrical shape. Compared to the case of using, the cost can be reduced and the weight can be reduced. Moreover, by providing the high friction layer 50 containing alumina particles 95 (inorganic particles), a good conveying force is exhibited. Furthermore, since the roller body 16 has higher accuracy with respect to the shape and dimensions as described above, the conveyance unevenness due to insufficient accuracy is also suppressed.

  Further, since the high friction layer 50 is selectively provided in the central portion excluding both ends of the roller body 16, that is, the central portion that directly contacts the paper P (recording medium), the conveyance performance of the paper P is lowered. In addition, the material cost of the high friction layer 50 can be minimized. Moreover, in the roller main body 16 according to the second embodiment, the high friction layer 50 is provided in at least the region corresponding to the central bent portion 84, so that the material cost of the high friction layer 50 is also minimized. be able to. However, the conveyance roller of this invention is not limited to this, For example, the high friction layer 50 can also be formed over the full length of the roller main body 16. FIG.

  Further, in the transport unit 10 of the present embodiment, as described above, the cost can be reduced and the weight can be reduced, and the transport roller 15 in which transport unevenness is suppressed is provided. Down and weight reduction are possible. Furthermore, the conveyance property of the recording medium by the conveyance roller 15 is also excellent.

  Moreover, since the inkjet printer (printing apparatus) 1 of this embodiment is provided with the above-mentioned conveyance unit, cost reduction and weight reduction are possible. Furthermore, the recording medium can be transported satisfactorily. The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, in the above-described embodiment, with respect to the joint of the cylindrical shafts (roller main bodies) according to the present invention, as shown in FIG. Although it is orthogonal to the central axis of the main body 16, it is not limited to this.

  The intersecting portion 82 (86) is formed by the pair of intersecting portions 82 (86) and the second straight portion 83b (87b) in the bent portion 81 (both end bent portions 85) without being orthogonal to the central axis. You may form the angle (alpha) of the front end side of the convex piece 88 which becomes the obtuse angle (less than 180 degrees). In this way, when the pair of end portions 61a and 61b are brought close to each other in the press working of the metal plate, the tip of the convex piece 88 is easily fitted into the corresponding concave portion. Therefore, the roller body 16 can be prevented from being distorted or twisted.

  Moreover, although the conveyance roller which concerns on this invention was applied to the conveyance roller 15 in the conveyance roller mechanism 19 in embodiment mentioned above, it is not restricted to this. The present invention can also be applied to the paper discharge roller 29 and the paper discharge jagged roller 31 in the paper discharge roller mechanism 27. Furthermore, it can also be applied to the driven roller 17 (roller 17a) in the transport roller mechanism 19.

DESCRIPTION OF SYMBOLS 1 ... Inkjet printer (printing apparatus), 10 ... Conveyance unit, 15 ... Conveyance roller, 16 ... Roller main body (cylindrical axis), 16a ... Central axis, 17 ... Driven roller, 19 ... Conveyance roller mechanism, 21 ... Print head (printing) Part), 50 ... high friction layer, 51 ... resin film, 60 ... metal plate, 61a, 61b ... end, 62a, 62b ... side part, 65 ... large metal plate, 80 ... joint, 80a-80c ... joint 80d, 80e ... Connection part, 82 ... Intersection, 83a ... First straight part, 83b ... Second straight part, 84 ... Central straight part, 85 ... Both ends bent part, 86 ... Intersection, 87 ... Connection straight line Part, 87a ... first straight part, 87b ... second straight part, 88, 89 ... convex piece, 90 ... painting booth, 95 ... alumina particles (inorganic particles),

Claims (12)

A cylindrical shaft formed in a cylindrical shape with a pair of end portions facing each other by pressing, and having a joint between the pair of end portions,
The joint is
A first connecting portion extending in the central axis direction of the cylindrical shaft;
A second connecting portion provided on the opposite side of the first connecting portion across the central axis, connected to an end of the first connecting portion, and extending in the central axis direction;
A cylindrical shaft characterized by comprising:   2. The cylindrical shaft according to claim 1, wherein the second connecting portion is divided and provided at a position sandwiching the first connecting portion in the central axis direction.   The cylindrical shaft according to claim 1, wherein the first connecting portion is provided at a central portion of the cylindrical shaft in the central axis direction.   The cylindrical shaft according to claim 2 or 3, wherein the second connecting portion is provided at a position shifted in a circumferential direction of the cylindrical shaft.   The cylindrical shaft according to any one of claims 1 to 4, wherein the first connecting portion and the second connecting portion are formed to have substantially the same dimension in the central axis direction. . The pair of end portions forming the second connecting portion has an uneven portion that fits one end portion and the other end portion of the pair of end portions. The cylindrical shaft according to one item. A cylindrical shaft rotatably provided;
A transport unit that is provided on a surface of the cylindrical shaft and transports a transported medium;
The conveyance roller characterized by using the cylindrical axis as described in any one of Claims 1-6 as said cylindrical axis.   The conveyance roller according to claim 7, wherein the conveyance unit has a high friction layer containing inorganic particles.   The transport roller according to claim 7 or 8, wherein the first joint portion of the cylindrical shaft is provided in the transport unit.   The transport roller according to any one of claims 7 to 9, wherein the second connecting portion of the cylindrical shaft is provided in a portion off the transport unit. A transport roller provided rotatably and having a transport unit for transporting a transported medium;
A driving device for driving the transport roller;
A driven roller that rotates while holding the medium to be transported with the transport roller,
The conveyance apparatus as described in any one of Claims 7-10 is used as the said conveyance roller. The conveyance apparatus characterized by the above-mentioned. A transport unit for transporting a transported medium;
A printing unit that performs a printing process on the recording medium conveyed by the conveying device,
The printing apparatus according to claim 11, wherein the conveyance device according to claim 11 is used as the conveyance unit.

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