JP4984088B2 - Sheet conveying device, driven roller mold and image recording device - Google Patents

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet-like recording medium, and in particular, a sheet conveying apparatus that includes a driving roller and a driven roller that is in pressure contact with the driving roller and is configured to convey the recording medium. The present invention relates to an image recording apparatus including a driven roller mold and a sheet conveying device.

  2. Description of the Related Art Conventionally, in an image recording apparatus such as an inkjet method, a sheet conveying apparatus that conveys a recording sheet (a recording medium, hereinafter simply referred to as a sheet) toward a platen generally includes a driving roller that is rotated by a driving force such as a motor. The driven roller is disposed opposite to the driving roller and rotates following the driving roller.

  By the way, with respect to the driving roller that is long in the width direction of the paper, the driven roller is disposed on the outer peripheral surface of the driving roller at an appropriate interval in the axial direction of the driving roller. The roller surface (outer peripheral surface) of the conventional driven roller is formed on a cylindrical surface concentric with the rotation center axis, and both ends in the axial direction of this cylindrical surface are angular due to the design of the molding die, that is, the driven Since the end surface of the roller is a surface orthogonal to the axis with respect to the roller surface (cylindrical surface) of the roller, both ends of the driven roller often have substantially 90 ° sharp edges (edges).

  If the corners (edges) of the cylindrical surface are in contact with the peripheral surface of the drive roller, streaky indentation due to the sharp angle edge remains on the paper nipped by the driven roller and the drive roller. This was a cause of deterioration in image recording quality.

  In order to solve the above problem, Patent Document 1 proposes a so-called barrel-shaped driven roller in which the outer diameter of the axially central portion of the driven roller is large. In that case, the cavity portion (space portion) of the roller molding die corresponding to this also becomes a barrel shape, and must be forcibly removed in the axial direction after the molten resin is cooled and solidified. Therefore, there is a difficulty that the outer peripheral surface of the driven roller is damaged due to the pulling operation.

As a configuration for eliminating this inconvenience, in Patent Document 1, the outer diameter of the axial center portion of the roller surface after cooling and shrinkage of the resin of the driven roller is equal to the axial end portions including both axial ends of the roller surface. The axial center of the roller surface is formed as a cylindrical surface concentric with the axial center, and the inner diameter of the axial central portion of the roller surface after cooling shrinkage of the resin is set at both axial ends. The inner diameter at both ends in the axial direction is larger than the outer diameter at the central portion in the axial direction of the roller surface after cooling and shrinkage of the resin. Thus, when the driven roller is extracted from the molding die in the axial direction, the outer diameter portion of the central portion in the axial direction of the roller surface is allowed to pass without being caught by the side end of the molding die.
JP 2001-97593 A

  However, the barrel-shaped bulge at the outer diameter of the central portion of the roller surface, which is the difference between the outer diameter of the central portion of the roller surface and the outer diameter of both end portions in the axial direction, effectively gives only a contraction degree of the resin material. Can not. For this reason, in practice, it is completely possible to cancel the sink at the center of the roller surface and obtain a cylindrical driven roller having a constant outer diameter. If it does so, the problem that an indentation generate | occur | produces on a sheet | seat due to the sharp corner | angular part (edge) in the one end part (or both ends) of a roller surface cannot be solved.

  The present invention has been made in view of the above circumstances, and is a driven roller integrally formed of a resin material so as not to cause indentation on a sheet (recording medium) and to take out from a molding die. It is another object of the present invention to provide a sheet conveying apparatus including a driven roller that can be smoothly operated, a driven roller mold, and an image recording apparatus including the sheet conveying apparatus.

In order to achieve the above object, the invention according to claim 1 is a sheet conveying apparatus that conveys the recording medium to a support base on which the sheet-like recording medium is placed during image recording, and includes a driving roller, and A driven roller is disposed so as to face the drive roller, and the driven roller is made of resin, and at least two of the driven rollers are paired and can be rotated through one rotating support shaft. The rotation support shaft is supported so as to urge the driven roller to the drive roller by an urging force in an elastic support portion, and is located at a position close to one end surface of the driven roller, the center of the driven roller A radius R1 in a cross section perpendicular to the axis, a position close to the other end face of the driven roller, and a radius R3 in a cross section perpendicular to the central axis, between the one end face and the other end face in the driven roller A position, when the radius R2 in a cross section perpendicular to the central axis, is set to R1 ≧ R2> R3, between the cross section including the cross-section and the radius R2 including the radius R1 in each of the driven rollers The first roller surface is formed in a cylindrical surface substantially concentric with the central axis, and the second roller surface between the cross section including the radius R2 and the cross section including the radius R3 is substantially the center axis. When the distance between the cross section including the radius R2 and the cross section including the radius R3 is L23, the angle tan -1 is formed. [(R2-R3) / L23] is set larger than the maximum deflection angle formed by the rotation support shaft and the axis of the drive roller, and the two driven rollers in contact with the drive roller are respectively On the side closer to the cross section having radius R3 The end surface is disposed so as to be directed to the side closer to the elastic support portion at a position closest to the driven roller.

A second aspect of the present invention is the molding die for the driven roller according to the first aspect , wherein the dividing surface of the cavity mold and the core mold is located at a cross section including the radius R1 in the rotation axis direction. Or it is located on the opposite side of the position of the cross section containing the said radius R3 on both sides of the position of the cross section containing the said radius R1.

According to a third aspect of the present invention, there is provided a sheet conveying apparatus that conveys the recording medium to a support base on which the sheet-like recording medium is placed during image recording, and is opposed to the driving roller and the driving roller. The driven roller is made of resin, and at least two driven rollers are paired and supported rotatably via a single rotation support shaft. The support shaft is supported so as to urge the driven roller to the drive roller by the urging force in the elastic support portion, and has a sharp angle only at one end portion of the outer peripheral surface of the driven roller that is in contact with the drive roller. A portion is formed, and the corner portion is disposed on the side farther from the elastic support portion at a position closest to the driven roller.

According to a fourth aspect of the present invention, there is provided the sheet conveying apparatus according to the first or third aspect , and a recording head that performs image recording based on an ink jet recording method on a recording medium conveyed by the sheet conveying apparatus. An image recording apparatus.

The sheet conveying apparatus according to claim 1, further comprising a driving roller and a driven roller disposed so as to face the driving roller, wherein the driven roller is made of resin, and at least two of the driven rollers are paired with each other. Thus, it is supported so as to be rotatable through a single rotation support shaft. The rotation support shaft is supported so as to urge the driven roller to the drive roller by an urging force in an elastic support portion, and is located at a position near one end surface of the driven roller, the center axis of the driven roller. A radius R1 in a vertical cross section, a position close to the other end face of the driven roller, a radius R3 in a cross section perpendicular to the central axis, and a position between the one end face and the other end face in the driven roller; When a radius R2 in a cross section perpendicular to the central axis is set, R1 ≧ R2> R3 is set, and when a distance between a cross section including the radius R2 and a cross section including the radius R3 is L23, an angle tan ⁻¹ [ (R2-R3) / L23] is set to be larger than the maximum deflection angle formed by the rotation support shaft and the axis of the drive roller, and the two driven rollers in contact with the drive roller The roller is arranged so that the end face on the side close to the cross section having the radius R3 is directed to the side closer to the elastic support portion at the nearest position with respect to the driven roller.

With this configuration, the first condition R1 ≧ R2> R3 and the angle tan ⁻¹ [(R2−R3) / L23] are the maximum deflection between the rotation support shaft and the axis of the drive roller. In consideration of the second condition that it is set to be larger than the angle, the elastic support at the closest position to the driven roller is the end surface portion of the driven roller near the cross section having the radius R3. By arranging so as to face the side closer to the portion, the corner portion on the small diameter side (cross-sectional side having the radius R3) of the roller surface does not come into contact with the roller surface (outer peripheral surface) of the driving roller. As a result, the recording medium sandwiched between the driven roller and the drive roller does not generate indentations due to the corners.

  When a large number of driven rollers having the above-described shape are formed by injection molding simultaneously with a resin, in order to reduce variation in accuracy of each cavity portion for multi-cavity picking, the molding die has the radius R1. A first die having a cavity portion having a roller surface from the radius R3 to a radius R3, a second die having a cavity portion from the radius R1 to one end surface of the driven roller, and the radius R3 to the driven roller. It is common and practical to divide into three molds (blocks) with a third mold having a cavity portion up to the other end surface.

  In the driven roller formed by such three dies, corner portions (edge portions) having sharp angles are usually formed at both ends of the roller surface. Even with such a driven roller in which corners are formed at both ends, indentations due to the corners do not occur on the recording medium sandwiched between the driving rollers.

According to the first aspect of the present invention, the first roller surface between the cross section including the radius R1 and the cross section including the radius R2 in each driven roller is substantially a concentric cylinder with the central axis. The second roller surface between the cross section including the radius R2 and the cross section including the radius R3 is formed into a planar shape, and is a frustoconical surface or a frustoconvex convex rotating body substantially concentric with the central axis. It is formed in the shape of a peripheral surface.

  In other words, the roller surface of each driven roller is substantially cylindrical and concentric with the central axis, and is continuous with the first roller surface and is equal to the radius of the cylindrical surface. And a second roller surface having a frustoconical surface shape or a circumferential surface shape of the frusto-convex curved surface rotating body having a cross section (small diameter portion) including the radius R3 smaller in radius than the cross section including the radius R2. It will be.

  Accordingly, the portion of the roller surface of the driven roller that contacts the roller surface of the driving roller is only in an appropriate range of the first roller surface and the second roller surface across the cross section including the radius R2. As a result, the corner portions, which are the end portions of the first roller surface and the second roller surface, do not come into contact with the recording medium, so that no indentation is generated. The driven roller whose second roller surface has a truncated conical shape is easy to process and measure. On the other hand, in the driven roller in which the second roller surface is a peripheral surface of the truncated convex curved surface rotator, the tangent line on the surface including the central axis at the transition point (contact point) from the first roller surface to the second roller surface. Change is continuous. In other words, the tangent line changes very smoothly from the first roller surface to the second roller surface. Therefore, it is possible to reliably prevent the occurrence of indentation on the print medium.

According to a second aspect of the present invention, the mold for molding the driven roller is such that the dividing surface of the cavity mold and the core mold has a position of a cross section including the radius R1 or a position of a cross section including the radius R1 in the rotation axis direction. It is located on the opposite side to the position of the cross section including the radius R3.

Therefore, in the rotation axis direction, the direction of pushing the driven roller in which the resin is solidified from the core mold becomes the large diameter direction from the small diameter portion side, and has the same action and effect as when a so-called draft is formed in the core mold, There is an effect that the driven roller can be taken out from the molding die very easily.

According to a third aspect of the present invention, there is provided a sheet conveying apparatus that conveys the recording medium to a support base on which the sheet-like recording medium is placed during image recording, and is opposed to the driving roller and the driving roller. The driven roller is made of resin, and at least two driven rollers are paired and supported rotatably via a single rotation support shaft. The support shaft is supported so as to urge the driven roller to the drive roller by the urging force in the elastic support portion, and has a sharp angle only at one end portion of the outer peripheral surface of the driven roller that is in contact with the drive roller. A portion is formed, and the corner portion is disposed on the side farther from the elastic support portion at a position closest to the driven roller.

  In the mold for molding the driven roller made of resin, the solidified product inside the molding space is taken out from the mating surfaces of at least two molds. This separation surface is generally formed at one end of the roller surface of the driven roller. In that case, by arranging the corner portion on the side farther from the elastic support portion at a position closest to the driven roller, the corner portion is arranged on the side farther from the elastic support portion where the amount of deflection of the rotation support shaft with respect to the drive roller is large. The corner portion is positioned, and the impression of the recording medium does not occur in the sandwiched portion between the driven roller and the driving roller.

According to a fourth aspect of the present invention, there is provided the sheet conveying apparatus according to the first or third aspect , and a recording head that performs image recording based on an ink jet recording method on a recording medium conveyed by the sheet conveying apparatus. An image recording apparatus.

  With such an image recording apparatus, no impression is generated when the recording medium is sandwiched between the roller surface of the driven roller and the driving roller during image recording, and the recording quality of the image is reduced due to the impression. There is an effect that it does not deteriorate.

  An embodiment of the present invention will be described below with reference to the drawings as appropriate. In addition, the following embodiment is only an example in which the present invention is embodied, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.

  FIG. 1 is a perspective view showing an external configuration of a multi-function device 1 according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an outline of the internal configuration of the multi-function device 1. FIG. 3 is a plan view showing the main configuration of the recording unit 10. FIG. 4 is a partial cross-sectional view showing a configuration around the conveyance roller pair 27.

[Basic structure of multi-function device 1]
As shown in FIG. 1, an opening 2a is opened on the front side (front side in FIG. 1) of a housing 2 (synthetic resin housing) in the multi-function device 1, and a recording medium is provided in the opening 2a. The sheet feeding tray 3 having an open upper surface for storing sheets in a stacked state is mounted so as to be insertable / removable along the X-axis direction. An auxiliary paper feed tray 33 for feeding small-size paper is mounted on the upper surface of the paper feed tray 3, and a paper discharge tray portion 33a is formed on the upper surface of the rear portion. The term “insertion / removal” is not limited to the case where the paper feed tray 3 is detachable from the housing 2, and even when the paper feed tray 3 is pulled out of the housing 2, This is intended to include those in which the tray 3 cannot be removed (cannot be attached or detached).

  An image reading device 5 with an automatic document feeding mechanism for reading a document in a copy function or a facsimile function is disposed on the upper part of the housing 2 made of synthetic resin. The image reading device 5 is configured to be vertically openable and closable with respect to one side end of the housing 2 via a pivot portion (not shown). Further, the upper surface of the image reading device 5 is constituted by a glass plate (not shown) for placing a document, and this glass plate can be turned up and down around the pivot with respect to the rear end of the image reading device 5. The document cover body 6 is covered. The document cover body 6 is opened upward, the document is placed on the glass plate, and an image of the document is read by a document reading scanner (for example, CIS: Contact Image Sensor) that reciprocates in the main scanning direction below the glass plate. Read.

  The printer function is a function in which the recording unit 10 records an image or document on a sheet based on image data or document data transmitted from a computer (not shown). The scanner function is a function for transferring image data of a document read by the scanner unit to a computer connected to the apparatus by wire or wirelessly. The read image data can also be transferred to various storage media such as a memory card and stored. The copy function is a function in which the recording unit 10 records the image data read by the scanner unit on the paper P. The facsimile function is a function for transmitting image data read by the scanner unit by facsimile via a telephone line or the like. The received facsimile data is recorded on the paper P by the recording unit 10.

  On the upper surface of the housing 2 and in front of the document cover body 6, there are an operation panel unit 7 having various operation buttons, and a display device 8 using a liquid crystal or the like for displaying operation procedures and the status of processes being executed. Is provided. The various operation buttons include a start button, a stop button, and the like, and various operations are performed by pressing these operation buttons. In addition, the setting state of the multi-function device 1 and various operation messages are displayed as necessary.

  An external memory insertion portion 11 for inserting an external memory is provided on the front surface of the housing 2 and above the opening 2a. The external memory corresponds to, for example, CompactFlash (registered trademark), SmartMedia (registered trademark), Memory Stick (registered trademark), SD card (registered trademark), xD (registered trademark), and the like. The data stored in the external memory inserted into the external memory insertion unit 11 is read into the internal memory of the multi-function device 1 and recorded on the paper P by the recording device.

Next, the recording unit 10 and the paper feeding device 12 will be described with reference to FIGS. FIG. 2 is a side sectional view of the recording unit 10 and the paper feeding device 12, and FIG. 3 is a schematic plan view of the recording unit 10.
[Schematic Configuration of Recording Unit 10]
The recording unit 10 records an image on the paper P according to an inkjet recording method. The recording unit 10 according to the present embodiment uses a four-color ink, that is, each color ink of cyan (C), magenta (M), yellow (Y), and black (Bk), to form a color image or a monochrome image on the paper P. Record. The recording head 14 receives ink of each color of cyan (C), magenta (M), yellow (Y), and black (Bk) from an ink cartridge 19 provided inside the housing 2 through an ink tube 20 (see FIG. 4). The ink is supplied and selectively ejected as fine ink droplets. While the carriage 13 is reciprocated, ink droplets are selectively ejected from the recording head 14, whereby image recording is performed on the paper P conveyed on the platen 26 (supporting base in the present invention). .

  The recording unit 10 is supported by a main frame (not shown) made of a bowl-shaped metal plate having an open upper surface and a pair of left and right side plates, and extends in the Y-axis direction (main scanning direction). It is formed between the first and second guide members 22 and 23 (see FIGS. 2 and 3). The carriage 13 on which the recording head 14 of the recording unit 10 is mounted on the lower surface side is supported so as to be slidable across the first guide member 22 on the upstream side and the second guide member 23 on the downstream side in the paper transport direction ( It can be moved back and forth.

  In order to reciprocate the carriage 13, timing is arranged on the upper surface of the second guide member 23 arranged on the downstream side in the paper conveyance direction (arrow A direction) so as to extend in the main scanning direction (Y-axis direction). A belt 25 is wound around a pulley, and a CR (carriage) motor 24 that drives the timing belt 25 is fixed to the lower surface of the second guide member 23.

  A flat platen 26 extending in the Y-axis direction so as to face the lower surface of the recording head 14 in the carriage 13 is fixed between the guide members 22 and 23 and above the bottom plate of the main frame.

[Paper Feeder]
The sheet feeding device 12 includes a sheet feeding tray 3 or an auxiliary sheet feeding tray 33, a feeding unit 20, and sheet conveying devices disposed upstream and downstream in the conveying direction of the carriage 13. The recording medium accommodated in the paper feeding tray 3 or the auxiliary paper feeding tray 33 is hereinafter referred to as a paper for the sake of convenience. The recording medium is not only plain paper, but also cardboard, envelope and other thick paper, glossy paper, etc. It is a concept that includes special paper and resin film. Note that the auxiliary paper feed tray 33 is not necessarily provided on the paper feed tray 3, and only the paper discharge tray portion 33a may be provided.

[Feeding means]
In the embodiment, the arm 20c made of synthetic resin in the pendulum type feeding means 20 can be turned up and down around the drive shaft 29. The arm 20c extends so as to approach the inclined separation plate 21, and the arm body 20c. A feeding roller 20a is disposed at the tip of 20c. The feed roller 20a is rotationally driven from the drive shaft 29 through a gear transmission mechanism (not shown) provided on the arm body 20c (see FIG. 2). The gear transmission mechanism includes a plurality of transmission gears and a planetary gear. Note that the pair of feed rollers 20a in the embodiment are provided at symmetrical positions with respect to the center line in the Y direction.

  The paper P in the paper feed tray 3 or the auxiliary paper feed tray 33 is separated by the feeding roller 20a of the feeding means 20 and the inclined separation plate 21 disposed on the back side (left end side in FIG. 2) of the paper feed tray 3. The sheets are separated one by one by cooperation with the claws and fed to the U-turn-shaped conveyance path 9. Then, the sheet is fed one by one to the recording unit 10 through a sheet conveying device of the present invention, which will be described later, and after the image is recorded by the recording head 14, the sheet is discharged to the discharge tray unit 33 a through the discharge roller pair 28. The FIG. 2 shows a position where the auxiliary paper feed tray 33 is retracted with respect to the paper feed tray 3, and the paper accumulated and stored in the paper feed tray 3 can be fed. If the auxiliary paper feed tray 33 is pushed inward, the feed roller 20a can come into contact with the paper on the auxiliary paper feed tray 33.

[Sheet Conveying Device]
A registration roller (conveyance roller) pair 27 for feeding the paper P to the lower surface of the recording head 14 is disposed on the upstream side of the platen 26, and the recorded paper P is placed on the downstream side of the platen 26. A pair of paper discharge rollers 28 for transporting onto a paper discharge tray section 33a provided on the upper surface of the paper feed tray 3 is disposed. The platen 26 supports the paper P conveyed by the registration roller (conveyance roller) pair 27 so that the gap between the platen and the recording head is constant.

  The paper discharge roller pair 28 includes a driving roller 28a and a spur roller 28b. The spur roller 28b is provided so as to face the upper side of the drive roller 28a. The spur roller 28b is in pressure contact with the drive roller 28a. The recorded paper P is pinched by the driving roller 28a and the spur roller 28b and further conveyed downstream. The spur roller 28b is also urged against the driving roller 28a so as to be able to come into pressure contact. However, since the spur roller 28b is pressed against the recorded paper P, a roller is used so as not to deteriorate the image recorded on the paper P. The surface is spur-shaped and uneven.

  FIG. 4 shows a cross-sectional structure around the conveyance roller pair 27. In FIG. 4, the carriage 13, the first and second guide members 22 and 23, the discharge roller pair 28 and the like are not shown.

  The registration roller (conveying roller) pair 27 as the sheet conveying apparatus of the present invention includes a driving roller 35 and a driven roller 36 (also referred to as a pinch roller) disposed so as to face the driving roller 35. In the present embodiment, the drive roller 35 is made of ceramics and is integrally formed long along the Y-axis direction. A plurality of driven rollers 36 are arranged below the one drive roller 35 at appropriate intervals.

  As shown in FIGS. 4 to 6, the two pairs of driven rollers 36 are rotatably supported by one rotation support shaft 46, and this one rotation support shaft 46 is supported by a roller holder 37 and an auxiliary holder 38. It is rotatably supported. In the present embodiment, four holder support members 39 are arranged side by side and in a straight line in the axial direction of the drive roller 35, and each holder support member 39 has a roller holder 37, an auxiliary holder 38, a driven roller 36, and the like. These members are supported. Therefore, the holder support member 39 and thus the roller holder 37 and the auxiliary holder 38 are arranged at predetermined intervals along the axis of the drive roller 35 (parallel to the Y axis). In the following, for convenience of explanation, the configuration of one holder support member 39 and each member supported by the holder support member 39 will be described.

  Each holder support member 39 is attached to a main frame forming a casing of the apparatus. The roller holder 37 and the auxiliary holder 38 are supported by a holder support member 39 so as to be able to roll in the paper P conveyance direction.

  By adopting such a rolling support mechanism, when the leading edge of the paper P enters the pinching portion of the conveyance roller pair 27, the roller holder 37 together with the driven roller 36 is conveyed from the upstream retracted position to the downstream side. Roll to position. When the trailing edge of the sheet P comes out of the holding portion of the conveying roller pair 27, the roller holder 37 rolls together with the driven roller 36 from the downstream conveying position to the upstream retracted position. Such a rolling support mechanism is provided for improving the image quality, but is not an essential requirement for the present invention.

[Configuration of Support Mechanism for Follower Roller 36]
The support mechanism of the driven roller 36 includes a holder support member 39, a rolling bearing 40, a roller holder 37, an auxiliary holder 38, a coil spring 41 (corresponding to an urging member of the present invention), and a driven roller 36.

  As shown in FIGS. 5 and 6, the holder support member 39 is formed in a long shape. The holder support member 39 is made of a synthetic resin typified by polystyrene resin (PS). The holder support member 39 serves as a base for supporting the rolling bearing 40, the holder support member 39, the auxiliary holder 38, the coil spring 41, and the driven roller 36.

  The holder support member 39 is fixed to the main frame constituting the recording unit 10. Specifically, the holder support member 39 is positioned by fitting two protruding claws 42 provided on one side of the holder support member 39 into an engagement groove (not shown) of the frame. A mounting seat 43 extending from the lower end to the downstream side is provided on the other side surface. When a screw is screwed into the through hole 44 provided in the mounting seat 43 in a state where the holder support member 39 is positioned with respect to the frame, the mounting seat 43 is screwed to the frame. Thereby, the holder support member 39 is fixed to the frame.

  The roller holder 37 is supported by a recessed portion formed in an upwardly open shape on the upper surface of the holder support member 39 via a rolling bearing 40 having a roller 40a on a support bottom surface 45 having an arcuate side section. .

  As shown in FIGS. 5 and 6, the roller holder 37 is formed in a long shape, like the holder support member 39. The roller holder 37 is made of a synthetic resin such as polyacetal resin (POM). In the present embodiment, the auxiliary holder 38, the coil spring 41, the driven roller 36, and the rotation support shaft 46 thereof are assembled to the roller holder 37 to constitute one assembly (assembly), and this assembly is the holder support member 39. It is supported in the recess.

  The roller holder 37 is disposed in the recess so that its longitudinal direction (Y-axis direction) coincides with the axial direction of the drive roller 35 and its short direction coincides with the conveyance direction (X-axis direction) of the paper P. The

  Cutouts 47 are formed at both ends of the roller holder 37 in the longitudinal direction. The notch 47 is formed in a substantially rectangular shape in plan view. The support arm 48 of the auxiliary holder 38 is inserted into these notches 47 from above. Hook ribs 49 are provided on both sides of the notch 47 in the short direction, and the hooks 48 a of the support arms 48 are hooked on the hook ribs 49 when the support arms 48 are inserted.

  Support arms 48 are provided at both ends of the auxiliary holder 38 in the longitudinal direction. Each support arm 48 is a member that supports the auxiliary holder 38 in the roller holder 37 so as to be movable in the up-down direction, that is, in the direction in which it contacts and separates from the drive roller 35.

  The roller holder 37 is provided with spring housing chambers 50 that are open upward at both ends in the longitudinal direction (Y-axis direction). Each spring accommodating chamber 50 is provided adjacent to the inner side in the longitudinal direction from each notch 47. A coil spring 41 is accommodated in the spring accommodating chamber 50. The coil spring 41 is used as a so-called compression spring, and has a spring length and a spring force capable of pressing the rotation support shaft 46 of the driven roller 36 toward the drive roller 35. Instead of the coil spring 41, an elastic member such as a leaf spring or rubber may be used as the urging means.

  An auxiliary holder 38 to be described later is supported via a coil spring 41 on the upper side of the roller holder 37, that is, on the side facing the driving roller 35.

  A positioning rib 51 having a groove 52 at the upper end is provided on the inner side in the longitudinal direction (Y-axis direction) than the spring accommodating chamber 50. The positioning rib 51 is erected on the upper surface of the roller holder 37. The groove 52 is formed by being deeply cut in the vertical direction from the upper end of the positioning rib 51, and is formed in a substantially U shape in a side view. The positioning rib 51 is for positioning the driven roller 36 in the short direction (X-axis direction). Specifically, the auxiliary holder 38 is attached to the roller holder 37, and the rotation support shaft 46 of the driven roller 36 is supported by the auxiliary holder 38, and the rotation support shaft 46 is inserted into the groove 52 of the positioning rib 51. Thus, the rotation support shaft 46 is positioned in the short direction (see FIG. 5). The positioning accuracy of the rotary spindle 46 by the positioning rib 51 is determined by the size of the groove 52 and the size of the rotary spindle 46.

  A protruding piece 53 is provided at the center of the bottom surface of the roller holder 37 in the longitudinal direction (Y-axis direction). The protruding piece 53 is inserted into and engaged with an engaging groove 54 (see FIG. 6) formed on the bottom surface of the recessed portion of the holder support member 39. The protruding piece 53 is formed in a narrow shape protruding downward from the bottom surface of the roller holder 37. The protruding piece 53 and the engaging groove 54 are formed in a shape that is long in the short direction (X-axis direction). By inserting the protruding piece 53 into the engagement groove 54, the roller holder 37 is positioned in the longitudinal direction (Y-axis direction) in the holder support member 39. Further, the moving range of the roller holder 37 is restricted in the conveyance direction of the paper P.

  A first guide rib 56 that protrudes in a direction substantially perpendicular to the side surface 55 is provided on the side surface 55 on the downstream side of the roller holder 37. Specifically, as shown in FIG. 5, the first guide rib 56 is provided on the side surface 55 so as to protrude toward the platen 26 provided on the downstream side of the roller holder 37. The first guide rib 56 is formed integrally with the roller holder 37. A plurality of first guide ribs 56 are provided in the axial direction of the driven roller 36, that is, in the longitudinal direction of the roller holder 37.

  The upper surface of the first guide rib 56 constitutes a guide surface that plays the role of directing the leading end toward the platen 26 when the paper P is conveyed toward the first guide rib 56.

  The auxiliary holder 38 is formed in a long shape like the roller holder 37 and the holder support member 39. The auxiliary holder 38 is made of a synthetic resin such as polyacetal resin (POM). The auxiliary holder 38 is attached to the upper side of the roller holder 37 so that the longitudinal direction thereof coincides with the axial direction of the drive roller 35.

  With the auxiliary holder 38 attached to the roller holder 37, the movement range of the auxiliary holder 38 is determined by the distance between the hook 48 a and the lower end of the latching rib 49. That is, the hook 48 a is separated from the lower end of the retaining rib 49 in a posture in which the auxiliary holder 38 is pressed downward with the auxiliary holder 38 attached to the roller holder 37. On the other hand, when the auxiliary holder 38 is lifted upward, the hook 48 a is hooked on the lower end of the hook rib 49.

  The auxiliary holder 38 is attached to the roller holder 37 from above the coil spring 41 in a state where the coil spring 41 is accommodated in the spring accommodating chamber 50. Therefore, in a state where no external force is applied to the auxiliary holder 38, the auxiliary holder 38 is always lifted upward by the biasing force of the coil spring 41. Conversely, when a downward external force is applied to the auxiliary holder 38, the coil spring 41 is compressed and the auxiliary holder 38 is displaced in a direction approaching the roller holder 37. In the present embodiment, as shown in FIG. 5, when each member is assembled and incorporated in the recording unit 10, the driven roller 36 is pressed against the drive roller 35, so the auxiliary holder 38 is also It is pressed downward via the driven roller 36. Therefore, in the state incorporated in the recording unit 10, the auxiliary holder 38 is held in a state in which it can move in the vertical direction within the above-described movement range.

  A plurality of second guide ribs 66 and one third guide rib 64 are provided on the upper surface of the auxiliary holder 38. These second guide ribs 66 are provided to smoothly guide the leading edge of the sheet P conveyed from the upstream side to the holding portion of the conveying roller pair 27. The third guide rib 64 is provided at the center in the longitudinal direction on the upper surface of the auxiliary holder 38.

Bearings 63 </ b> A are provided at both ends in the longitudinal direction of the auxiliary holder 38. The third guide rib 64 is also provided with a bearing 63B. The rotation support shaft 46 of the driven roller 36 is supported by the bearings 63A and 63B. The bearing 63A protrudes from the end 60 to the downstream side. Both ends of the rotation spindle 46 are supported by the bearing 63A. On the other hand, the center part of the rotation support shaft 46 is supported by the bearing 63B. The bearing 63 </ b> B is a groove-like member provided on the end 60 side of the third guide rib 64, and assists the rotation support shaft 46 when a load is applied downward to the rotation support shaft 46. To do.
[Following roller 36]
The driven roller 36 is made of a hard resin having high wear resistance (for example, a synthetic resin such as polyacetal resin, polycarbonate resin or thermoplastic polyimide resin, or natural resin such as celluloid) or the like, and is substantially in the shape of a frustoconical or substantially shell. It is formed on the peripheral surface of a truncated convex curved rotating body such as a cylinder. Here, the hard resin assumed in the present invention refers to a substance in which the deformation amount of the surface (roller surface) of the driven roller 36 per load is smaller than the deflection amount per load of the rotary support shaft 46. Further, the substantially barrel shape will be described in detail later. Further, a shaft hole 36 d through which the rotation support shaft 46 passes is formed in the inner diameter of the driven roller 36. The axis of the shaft hole 36d and the center shaft 36c of the driven roller 36 are coaxial.

  In the present invention, at least two driven rollers 36 are paired and supported rotatably via a single rotation support shaft 46, and the rotation support shaft 46 has at least one position at the coil spring 41 as described above. Is rotatably supported by a rotation support portion 73 that is elastically supported (see FIG. 8A). In addition, the structure of the rotation support part 73 in this invention is not limited to the structure of the above-mentioned embodiment, In the range which does not change the summary of this invention, it can change suitably.

In the first embodiment, the position is close to one end face 36a of each driven roller 36, the radius R1 in the cross section 70a perpendicular to the central axis 36c of the driven roller 36, and the position close to the other end face 36b of the driven roller 36. When the radius R3 in the cross section 71a perpendicular to the central axis 36c and the radius R2 in the cross section 71b perpendicular to the central axis 36c, which is a position between the one end face 36a and the other end face 36b in the driven roller 36,
R1 ≧ R2> R3 is set (see FIG. 7).

When the distance parallel to the central axis 36c from the position of the cross section 71b of the radius R2 to the position of the cross section 71a of the radius R3 is L23, the angle θ1 = tan ⁻¹ [(R2−R3) / L23] is 46 and the axis of the drive roller 35 are set to be larger than the maximum deflection angle θ2. Each driven roller 36 is such that the roller surface between the radius R1 and the radius R3 is in contact with the drive roller 36. 8A, 8B, 9, 10A, and 1 are in contact with each other. 8A, FIG. 8B, FIG. 9, FIG. 10A, and FIG. 10B, in order to clarify the action and effect, the deflection angle of the rotation support shaft 46 is set to be larger than the actual one. It is exaggerated. 9, 10 </ b> A, and 10 </ b> B, the shape of the driven roller 36 is also exaggerated.

  In the embodiment, the roller surface of each driven roller 36 has a cylindrical first roller surface 70 substantially coaxial with the central shaft 36c, a cross section 71b (large diameter portion) having a radius R2, and a radius R3. A second roller surface 71 having a frustoconical surface having a small cross section 71a (small diameter portion), and a radius R2 of the large diameter portion 71b is substantially equal to a radius R1 of the first roller surface 70 (cylindrical surface). Moreover, they are integrally formed continuously (see FIG. 7).

  The meaning that the radius R1 in the cross section 70a of the first roller surface 70 and the radius R2 of the cross section 71b in the second roller surface 71 are substantially equal (R2 ≦ R1) is as follows. This means that a draft angle smaller than θ1 when the driven roller 36 is pulled out along the axis may be provided on the first roller surface 70.

  As shown in FIG. 8A, two pairs of driven rollers 36 are supported on a single rotation support shaft 46 supported at both ends by two rotation support portions 73 having elastic urging force by a coil spring 41 or the like. When this is done, each driven roller 36 is disposed such that the small-diameter side having the second roller surface 71 of each driven roller 36 and having a cross-section 71 a is positioned closer to each rotation support portion 73. In other words, the first roller surface 70 having a cylindrical surface, which is the large diameter side of the driven roller 36, is disposed so as to be positioned on the center side of one rotation support shaft 46.

  As described above, the two driven rollers 36 are rotatably supported on one rotation support shaft 46 so that the first roller surface 70 is located on the center side in the longitudinal direction of the rotation support shaft 46. When the roller surface of the driven roller 36 is pressed against the peripheral surface (roller surface) of the driving roller 35 by the elastic biasing force of the both ends of the single rotation support shaft 46 by the coil spring 41 or the like, the rotation of both ends of the rotation support shaft 46 is rotated. Since there is a contact portion between the driven roller 36 and the drive roller 35 between the support portions 73, a bending moment is applied to the rotation support shaft 46 so that the center side in the longitudinal direction is separated from the peripheral surface of the drive roller 35. The central portion of the rotation support shaft 46 bends away from the peripheral surface of the drive roller 35. Therefore, the maximum deflection angle θ2 in that case occurs at the locations of the rotation support portions 73 at both ends of the rotation support shaft 46.

  In the first embodiment, when the second roller surface 71 has a frustoconical surface shape, a straight generatrix of the second roller surface 71 (here, a line segment forming the second roller surface 71 is referred to as a generatrix). The angle θ1 is set to be larger than the maximum deflection angle θ2 when the angle θ1 forms the central axis (see FIGS. 7 and 8A).

  When set as described above, the first roller surface 70 located on the center side in the longitudinal direction of the rotation support shaft 46 is a cylindrical surface substantially coaxial with the central axis of the rotation support shaft 46, and Since the deflection angle on the center side in the longitudinal direction is zero or close to zero and the amount of deflection is maximized, the location side of the cross section 70 a on the first roller surface 70 is slightly separated from the peripheral surface of the drive roller 35. On the other hand, the location side of the cross section 71 b of the second roller surface 71 is in contact with the peripheral surface of the drive roller 35. Also, the angle θ1 formed by the generatrix of the frustoconical second roller surface 71 with respect to the central axis is set to be larger than the maximum deflection angle θ2 of the rotation support shaft 46 with respect to the drive roller 35. The cross section 71a having the radius R3 in FIG. 8 does not contact the peripheral surface of the drive roller 35 (see FIG. 8A). Accordingly, the sheet P sandwiched between the driving roller 35 and the driven roller 36 is pressed against a roller surface region in an appropriate range including a cross section 71b that is a continuous portion (transition portion) between the first roller surface 70 and the second roller surface 71. Will be. Moreover, the peripheral surface of the transition portion between the first roller surface 70 and the second roller surface 71 sandwiching the cross section 71b having the radius R2 has no step, and the portion of the cross section 71a that is the smaller diameter side of the second roller surface 71 In addition, unlike the portion of the first roller surface 70 on the side of the cross section 70a, it is not angular, so that a streak-like impression does not occur.

In the second embodiment of the driven roller 36 shown in FIG. 14, the first roller surface 70 from the position of the cross section 70a having the radius R1 to the position of the cross section 71b having the radius R2 is the center axis of the rotation support shaft 46 (center axis 36c). The second roller surface 71 from the position of the cross section 71b having the radius R2 to the position of the cross section 71a having the radius R3 is a circumferential surface (so-called warhead type) of the truncated convex curve line rotating body. Alternatively, it may be substantially a shell, or the generatrix of the rotating body of the convex curve line may be a part of a convex curve line such as a parabola, an ellipse, a suspension curve, a cycloid curve, etc. In this embodiment, the radius R2 When the distance parallel to the central axis 36c from the position of the cross section 71b to the position of the cross section 71a of radius R3 is L23, the outer periphery of the position of the cross section 71b of radius R2 and the outer periphery of the position of the cross section 71a of radius R3 are connected. Line and center axis 36c An angle .theta.1 = tan ^-1 formed by the [(R2-R3) / L23 ]. Since the other configuration is the same as the first embodiment, the same components are given the same reference numerals.

  Thus, it is most preferable that the 2nd roller surface 71 is a surrounding surface of a truncated convex curve line | wire rotary body. In this embodiment, there is no step at the transition portion between the first roller surface 70 and the second roller surface 71, and it is smooth, so no streak indentation is generated as described above.

  On the other hand, when the two pairs of driven rollers 100 inserted and supported by one rotating support shaft 46 supported at both ends have cylindrical roller surfaces 100a over the entire circumference as in the prior art, the following is performed. become. That is, as shown in FIG. 8B, when the maximum deflection angle θ2 of the rotation support shaft 46 at the position of the rotation support portion 73 is set, the roller surface 100a of the driven roller 100 inserted and supported by the rotation support shaft 46 is The rotation support shaft 46 is inclined parallel to the maximum deflection angle θ2 and is separated from the circumferential surface of the drive roller 35 on the center side in the longitudinal direction of the rotation support shaft 46. In other words, of the roller surfaces 100 a of the pair of driven rollers 100, only the end portion 100 b on the side close to the end portion of the rotation support shaft 46 (the side close to the rotation support portion 73) contacts the peripheral surface of the drive roller 35. In other words, in the paper P sandwiched between the driving roller 35 and the driven roller 100, indentations are generated due to sharp corners (edges) at the end portion 100b of the roller surface 100a.

  In another embodiment of the present invention, when three or more driven rollers 36 are supported by a rotation support shaft 46 supported only at both ends by a rotation support portion 73 that elastically supports the rotation, The driven roller 36 disposed at a position closest to both end portions (rotation support portion 73) of the support shaft 46 has an end portion of the rotation support shaft 46 on the side having a cross section 71a having a radius R3 which is a small diameter on the second roller surface 71. What is necessary is just to arrange | position so that it may be located near (rotation support part 73) (refer FIG. 9).

  As a third embodiment of the present invention, as shown in FIG. 10 (A), one rotation support shaft 46 is composed of three auxiliary rotation support portions 75 at both ends and a main rotation support portion 74 at the center portion. The biasing force of the main spring 76 in the main rotation support portion 74 is set to be larger than the biasing force of the auxiliary spring 77 in the auxiliary rotation support portion 73. Then, the driven roller 100 in the form shown in FIG. 7 is rotatably supported on the rotation support shaft 46 between the auxiliary rotation support portions 75 at both ends across the main rotation support portion 74 at the center. In this case, each driven roller 36 is arranged so that the small diameter portion 71 b is closer to the main rotation support portion 74 having the main spring 76.

In this configuration, the main spring 76 force in the main rotation support portion 74 located between the contact points of the pair of driven rollers 36 that are in contact with the drive roller 35 is directed toward the drive roller 35, and this main rotation support portion The rotational support shafts 46 at 74 are bent in a direction approaching the drive roller 35. Therefore, the deflection angle of the rotation support shaft 46 corresponding to the location (location contacting the drive roller 35) of the cross section 71b (large diameter portion) on the second roller surface 71 of each driven roller 36 is the maximum deflection angle. The angle θ1 (= tan ⁻¹ [(R2−R3) / L23]) formed by the generatrix of the second roller surface 71 such as a frustoconical shape with the central axis is set to be larger than the maximum deflection angle. Therefore, only the part of the cross section 71b (or the part sandwiching the part) in the second roller surface 71 of each driven roller 36 is in contact with the driving roller 35, and has a sharp angle at both ends of the driven roller 36. The portions (the cross section 71 b side and the cross section 70 a side of the first roller surface 70) do not contact the drive roller 35. Accordingly, the sheet P sandwiched between the driving roller 35 and the driven roller 36 is pressed against a roller surface region in an appropriate range including a cross section 71b that is a continuous portion (transition portion) between the first roller surface 70 and the second roller surface 71. Will be. Moreover, the peripheral surface of the portion of the cross section 71b is an end of the second roller surface 71 (corner of the portion having the cross section 71a) or an end of the first roller surface 70 (corner of the portion having the cross section 70a). As shown in FIG. 4, the dent is not horny, and no streak-like impression is generated.

  In this embodiment, one main rotation support portion 74 and a pair of driven rollers 36 disposed on both sides of this portion are indispensable requirements, and the rotation support portions 73 at both ends have one rotation. This is provided to stabilize the posture of the support shaft 46 and is not an essential requirement.

  FIG. 10B is a modification of the third embodiment. Two driven rollers 36 (same as FIG. 7) are provided on both sides of the main rotation support portion 74 that is the central portion of the rotation support shaft 46. Form) is arranged. Also in this case, each driven roller 36 disposed on the side closest to the main rotation support portion 74 having the main spring 76 is oriented so that the portion of the cross section 71a is on the side close to the main rotation support portion 74. Be placed. Thereby, there can exist an effect similar to embodiment of FIG. 10 (A). In the embodiment shown in FIG. 9, FIG. 10 (A) and FIG. 10 (B), when the second roller surface 71 of the driven roller 36 is the peripheral surface of the truncated convex curve line rotating body as shown in FIG. There are also similar effects.

  A first embodiment of a mold for forming the driven roller 36 having the above-described configuration by injection molding is shown in FIG. This molding die is for taking a large number of three mold blocks. Of the first roller surface 70, a first die (core die) 80 having a molding space (cavity space) corresponding to the cylindrical roller-shaped first roller surface 70 and the second roller surface 71 having a frustoconical shape, etc. A second die (cavity die) 81 having a space corresponding to a small-diameter stepped portion 82 (corresponding to the one end surface 36a side of the driven roller 36) adjacent to the portion having the cross-section 70a, and a cross-section at the second roller surface 71 And a third mold 83 having a space corresponding to a small-diameter stepped portion 84 (corresponding to the other end surface 36b side of the driven roller 36) adjacent to the portion having 71a. Thus, a molding space (cavity space) 87 equal to the outer peripheral shape of the driven roller 36 is formed inside the three molds 80, 81, 83. An injection portion (spool) 88 for injecting molten resin into the molding space 82 is provided on the second mold 81 side.

  A core pin 85 for forming the shaft hole 36 d of the driven roller 36 is slidably inserted and supported by a third mold (cavity mold) 83. The core pin 85 passes through the molding space 87 such as the first mold (core mold) 80, and the tip of the core pin 85 is supported by the support recess of the third mold 83. The other end surface 36b close to the cross-section 71a side of the solidified driven roller 36 is pushed out into the molding space 87 by the protruding rod 86 provided on the outer periphery of the core pin 85 provided on the third die 83.

In the molding die shown in FIG. 11, the mating surface of the first die 80 and the second die 81 is a split surface (PL) for extruding the solidified driven roller 36. A sharp angle between the first roller surface 70 and the one end surface 36a of the driven roller 36 (for example, about 90 degrees, an angle less than that) is provided at the position of the mating surface of the first mold 80 and the second mold 81. ) 89 (edge) 89 is formed. A sharp corner (edge) 90 between the second roller surface 71 and the other end surface 36b of the driven roller 36 is formed at the position of the mating surface of the first mold 80 and the third mold 83.

  In order to take out the driven roller 36 solidified in the molding space 87 from the molding die, first, the first die 80 and the second die 81 are separated by the dividing surface PL, and then the core pin 85 is retracted from the molding space 87. After that, the driven roller 36 is removed from the first mold (core mold) 80 by extruding the other end surface 36 b into the molding space 87 by the protruding rod 86 disposed on the outer periphery of the core pin 85. The second roller surface 71 has a frustoconical shape or a cannonball shape with respect to the first roller surface 70 which is a substantially cylindrical surface, and pushes the driven roller 36 toward the large diameter side, so that the resin contracts. It can be extracted smoothly without relying on it. Usually, a molding space 87 in which 20 to 30 driven rollers 36 can be molded at once (manufacturing multiple pieces) is provided in one molding die, so that multiple cutting can be performed and manufacturing costs can be reduced. Can do.

  In the molding die shown in the second embodiment of FIG. 12, the first die (core die) having a space corresponding to the other end surface 36b of the driven roller 36 and the first roller surface 70 and the second roller surface 71 which are outer peripheral surfaces. ) 80 and a second die (cavity die) having a space corresponding to a stepped small diameter portion 82 (corresponding to the one end face 36a side of the driven roller 36) adjacent to the portion having the cross section 70a of the first roller surface 70. 81 and two molds are provided. A molding space 91 having the outer peripheral shape of the driven roller 36 is formed by combining the first mold 80 and the second mold 81. A sharp corner is not formed between the portion having the cross section 71a and the other end surface 36b of the driven roller 36, which is a rounded portion. The core pin 85 for forming the shaft hole 36d of the driven roller 36 is provided so as to be movable forward and backward in the axial direction so as to penetrate the forming space 91 with respect to the first die 80. Among the molding dies, the split surface PL between the first mold (core mold) 80 and the second mold (cavity mold) 81 sandwiches the position of the cross section including the radius R1 or the position of the cross section including the radius R1. The position is on the opposite side to the position of the cross section including the radius R3. Therefore, a sharp corner 93 is formed only at the end of the first roller surface 70 corresponding to the portion of the dividing surface PL. In the molding space 91, a portion (small diameter portion side) having a cross section 71 a of the second roller surface 71 is provided on the side far from the dividing surface PL. Further, an injection portion (spool) 88 for injecting the molten resin into the molding space 91 is provided on the second mold 81 side.

  In order to take out the driven roller 36 solidified in the molding space 91 from the molding die, first, the first die 80 and the second die 81 are separated by the dividing plane PL, and then the core pin 85 is removed from the molding space 91. After the retraction, the driven roller 36 is removed from the first die (core die) 80 by extruding the other end surface 36 b into the molding space 91 by the protruding rod 86 disposed on the outer periphery of the core pin 85. The second roller surface 71 has a frustoconical shape or a cannonball shape with respect to the first roller surface 70 which is a substantially cylindrical surface, and pushes the driven roller 36 toward the large diameter side, so that the resin contracts. It can be extracted smoothly without relying on it. Usually, a molding space 91 in which 20 to 30 driven rollers 36 can be molded at once (many pieces) is provided in one molding die. The driven roller 36 molded by the molding die shown in FIG. 12 may have a cylindrical surface as a whole.

  The driven roller 36 molded using the molding die shown in FIG. 12 has a corner 93 having a sharp angle (for example, 90 degrees or less) formed only at one end of its outer peripheral surface, and the other end is a rounded portion without a corner. Therefore, when such a pair of driven rollers 36 are rotatably supported on the rotation support shaft 46 supported at both ends by the elastic support portion 73, as shown in FIG. It is arranged on the side farther from the elastic support portion 73 at the nearest position (closer side) to the driven roller 36. In other words, the direction of the driven roller 36 is set so that the other end of the outer peripheral surface (roller surface) and the rounded portion is close to the nearest elastic support portion 73 (closer side). It is. As described above, when the pair of driven rollers 36 are arranged, the corner portion 93 having a sharp angle is located near the portion where the largest deflection amount of the rotation support shaft 46 is generated with respect to the driving roller 35. Since the corner portion 93 is greatly separated from the outer peripheral surface of the driving roller 35, no indentation is generated on the paper P sandwiched between the driving roller 35 and the driven roller 36.

  Further, the molded driven roller 36 may have a resin burr at the portion of the dividing surface PL. However, the portion where the burr is formed is formed on the side of the first roller surface 70 that is a cylindrical surface that is close to the one end surface 36a of the driven roller 36, so that it is sandwiched between the driving roller 35 and the driven roller 36 as described above. When the sheet P to be pressed is brought into pressure contact with a roller surface region in an appropriate range including a portion having a cross section 71b that is a continuous portion of the first roller surface 70 and the second roller surface 71, the sheet P is caused by the burr. There is no indentation.

  In addition, embodiment mentioned above is only an example of this invention, and can change suitably embodiment in the range which does not change the summary of this invention.

1 is a perspective view of a multi-function device 1 according to an embodiment of the present invention. 2 is a schematic cross-sectional view showing an outline of an internal configuration of the multi-function device 1. FIG. 2 is a plan view showing a main configuration of a recording unit 10. FIG. FIG. 4 is a partial cross-sectional view illustrating a configuration around a conveyance roller pair 27. FIG. 5 is a perspective view showing a state in which a roller holder 37 is supported by a holder support member 39. 4 is an exploded view of a holder support member 39 and a roller holder 37. FIG. It is sectional drawing along the axis line of the driven roller 36 of one Embodiment of this invention. (A) is sectional drawing which shows the state which has arrange | positioned a pair of driven roller 36 which concerns on this invention to the one rotating support shaft 46 elastically supported only at both ends, (B) is the whole cylindrical shape as a reference example. It is sectional drawing of the state which has arrange | positioned the following driven roller. It is sectional drawing which shows the state which has arrange | positioned the three driven rollers 36 based on this invention to the one rotating support shaft 46 elastically supported only at both ends. (A) is sectional drawing which shows the state which has arrange | positioned the pair of driven roller 36 which concerns on this invention on the one rotating support shaft 46 supported by 3 points | pieces, (B) is one piece supported by 3 points | pieces elastically. It is sectional drawing which shows the state which has arrange | positioned the two pairs of driven rollers 36 which concern on this invention to the rotation spindle 46 of this. 3 is a cross-sectional view showing a molding die according to a first embodiment for molding a driven roller 36. FIG. It is sectional drawing which shows the shaping | molding die of 2nd Embodiment for shape | molding the driven roller. It is explanatory drawing at the time of arrange | positioning the driven roller 36 formed with the shaping | molding die of 2nd Embodiment to the one rotating support shaft 46 elastically supported only at both ends. It is sectional drawing of the driven roller 36 of 2 embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multifunctional device 10 ... Recording part 13 ... Carriage 14 ... Recording head 26 ... Platen 35 ... Drive roller 36 ... Driven roller 36a ... One end surface 36b ... Other end surface 36c ... Center axis 36d ································································································································································································ • Auxiliary spring 80 ... 1st type 81 ... 2nd type 83 ... 3rd type 87 ... Molding space

Claims (4)

A sheet conveying apparatus for conveying the recording medium to a support base on which a sheet-like recording medium is placed during image recording,
A driving roller, and a driven roller arranged to face the driving roller;
The driven roller is made of resin,
At least two of the driven rollers are paired and supported rotatably through a single rotation support shaft,
The rotation support shaft is supported so as to urge the driven roller to the drive roller by an urging force in an elastic support portion,
A radius R1 in a cross-section perpendicular to the central axis of the driven roller at a position near one end surface of the driven roller;
A radius R3 in a cross section perpendicular to the central axis at a position close to the other end surface of the driven roller;
When the radius R2 is a position between the one end surface and the other end surface of the driven roller and is perpendicular to the central axis,
R1 ≧ R2> R3 is set,
The first roller surface between the cross section including the radius R1 and the cross section including the radius R2 in each driven roller is formed in a cylindrical surface substantially concentric with the central axis,
The second roller surface between the cross section including the radius R2 and the cross section including the radius R3 is formed in a frustoconical surface substantially concentric with the central axis or a circumferential surface of a frustoconvex curved rotating body. And
When the distance between the cross section including the radius R2 and the cross section including the radius R3 is L23, an angle tan -1 [(R2-R3) / L23] is formed between the rotation support shaft and the axis of the drive roller. It is set larger than the maximum deflection angle,
The two driven rollers that are in contact with the drive roller are such that the end surfaces on the side close to the cross section having the radius R3 are directed toward the side closer to the elastic support portion at the nearest position to the driven roller. A sheet conveying apparatus, wherein the sheet conveying apparatus is arranged. 2. The mold for molding the driven roller according to claim 1, wherein a split surface between the cavity mold and the core mold is a position of a cross section including the radius R <b> 1 or a position of a cross section including the radius R <b> 1 in the rotation axis direction. A mold for forming a driven roller, wherein the mold is located on the opposite side of the position of the cross section including the radius R3. A sheet conveying apparatus for conveying the recording medium to a support base on which a sheet-like recording medium is placed during image recording,
A driving roller, and a driven roller arranged to face the driving roller;
The driven roller is made of resin,
At least two of the driven rollers are paired and supported rotatably through a single rotation support shaft,
The rotation support shaft is supported so as to urge the driven roller to the drive roller by an urging force in an elastic support portion,
A corner with a sharp angle is formed only at one end of the outer peripheral surface of the driven roller that is in contact with the drive roller,
The sheet conveying apparatus according to claim 1, wherein the corner portion is disposed on a side farther from the elastic support portion at a position closest to the driven roller. A sheet conveying device according to claim 1 or 3,
An image recording apparatus comprising: a recording head that performs image recording based on an ink jet recording method on a recording medium conveyed by the sheet conveying apparatus.

Images