SHEET DISCHARGE DEVICE AND IMAGE SCANNING APPARATUS

A follow roller nips a sheet with a discharge roller. The follow roller is harder than the discharge roller. A paddle is rotatable together with the follow roller. The paddle includes protrusions and recesses arranged alternately in a circumferential direction of an axis of the follow roller. Each of the protrusions protrudes farther radially outward than an outer circumference of the follow roller to contact the sheet. Each of the recesses is recessed radially inward between two of the protrusions adjacent to each other in the circumferential direction. A groove is located between the follow roller and the paddle in a width direction parallel to a direction in which the axis extends. The groove is located at a same position as an end of the discharge roller in the width direction. The groove is recessed one round farther radially inward than the outer circumference of the follow roller.

REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No. 2022-004058 filed on Jan. 14, 2022. The entire content of the priority application is incorporated herein by reference.

BACKGROUND ART

A recording medium feeding device as an example of a sheet discharge device is known.

DESCRIPTION

A recording medium feeding device includes a first rotating member and a second rotating member. The second rotating member has a rotating member main body and a paddle. The rotating member main body is rotatable about an axis. The paddle rotates integrally with the rotating member main body. The paddle has protrusions and recesses that are alternately arranged in the circumferential direction of the axis. Each protrusion protrudes radially from the outer circumference of the rotating member main body and is configured to contact a recording medium. Each recess is radially recessed between two protrusions that are adjacent in the circumferential direction.

The first rotating member is covered with, for example, a rubber material. The second rotating member is made of, for example, plastic. That is, the rotating member main body is harder than the first rotating member.

The edge in the width direction parallel to the axis of the first rotating member is separated from the paddle. The outer circumference of the rotating member main body is a cylindrical surface that extends in the width direction to the paddle without steps or unevenness.

In such a sheet discharge device, the first rotating member rotates to apply a conveyance force to the recording medium to discharge the same. The rotating member main body nips the recording medium together with the first rotating member and rotates by following rotation of the first rotating member. At this time, the paddle kicks out the trailing edge of the recording medium with the protrusions and recesses, thereby suppressing discharge failure of the recording medium.

However, in the recording medium feeding device described above, the widthwise edge of the first rotating member, which is softer than the rotating member main body, is separated from the paddle, and the outer circumference of the rotating member main body is a cylindrical surface extending to the paddle in the width direction without steps or unevenness. Due to this configuration, the portion of the recording medium located outside the first rotating member in the width direction can be easily warped away from the protrusions and recesses.

As a result, in this recording medium feeding device, kicking of the trailing edge of the recording medium by the protrusions and recesses tends to be weak, and consequently, it may become difficult to suppress a discharge failure of the recording medium.

In view of the foregoing, an example of an object of this disclosure is to provide a sheet discharge device and an image scanning apparatus configured to suppress a sheet discharge failure.

According to one aspect, this specification discloses a sheet discharge device. The sheet discharge device includes a discharge roller, a follow roller, a paddle, and a groove. The discharge roller is rotatable to apply a conveyance force to a sheet and discharge the sheet. The follow roller is rotatable about an axis. The follow roller is configured to nip the sheet with the discharge roller and to rotate by following rotation of the discharge roller. The follow roller is harder than the discharge roller. The paddle is rotatable together with the follow roller. The paddle includes protrusions and recesses arranged alternately in a circumferential direction of the axis. Each of the protrusions protrudes farther radially outward than an outer circumference of the follow roller to contact the sheet. Each of the recesses is recessed radially inward between two of the protrusions adjacent to each other in the circumferential direction. The groove is located between the follow roller and the paddle in a width direction. The width direction is parallel to a direction in which the axis extends. The groove is located at a same position as an end of the discharge roller in the width direction. The groove is recessed one round farther radially inward than the outer circumference of the follow roller. Thus, the end of the discharge roller in the width direction presses the sheet toward the groove at a position between the follow roller and the paddle. Here, the discharge roller is softer than the follow roller. Thus, the sheet warps such that a portion of the sheet located outside the follow roller in the width direction enters the groove and approach the protrusions and the recesses. Thus, it is unlikely that kicking of a trailing edge of the sheet by the protrusions and the recesses is weakened. As a result, the sheet discharge device suppresses problems that the trailing edge of the sheet stays near the follow roller, that the leading edge of the subsequent sheet slips under the trailing edge of the staying sheet to change the discharge order of the sheets, and that the subsequent sheet collides with the trailing edge of the staying sheet to cause damage or jamming of the sheet. Thus, the sheet discharge device suppresses discharge failures of the sheet.

According to another aspect, this specification also discloses an image scanning apparatus. The image scanning apparatus includes an image scanner and a sheet discharge device. The image scanner is configured to scan an image on a sheet. The sheet discharge device is configured to discharge the sheet. The image scanning apparatus includes the sheet discharge device having the above-described configuration, and thus has similar advantages.

An image scanning apparatus1according to an embodiment is shown inFIG.1. A sheet discharge device5of the embodiment provided in the image scanning apparatus1is shown inFIGS.2to5.

InFIG.1, the side of an operation panel8P of the image scanning apparatus1is defined as front. The left side when facing the operation panel8P is defined as a left side. A front-rear direction, a left-right direction, and an upper-lower direction shown inFIG.2and subsequent figures correspond to the directions shown inFIG.1.

As shown inFIG.1, the image scanning apparatus1includes a main body8and a cover9. The main body8is a flat, substantially box-shaped body. The operation panel8P such as a touch panel is located on the front surface of the main body8. The main body8accommodates a print engine (image forming section)2in its lower portion. The print engine2forms an image on a sheet by an inkjet method, a laser method, and so on.

As shown inFIG.2, the main body8accommodates an image scanner (image reading section)3in its upper portion. The image scanner3has a document support surface3A, a reading surface3B, a reading sensor3S, and a scanning mechanism (not shown).

The document support surface3A is an upper surface of a large-area platen glass located on the upper surface of the main body8. The reading surface3B is an upper surface of a platen glass that is located to the left of the document support surface3A on the upper surface of the main body8and that is elongated in the front-rear direction.

The document support surface3A supports a document to be read. Documents to be read are sheets such as paper and OHP sheets, books, and so on. The reading surface3B is used when a conveyor4described later operates.

The reading sensor3S is a well-known image reading sensor such as a CIS (Contact Image Sensor) or a CCD (Charge Coupled Device), and is elongated in the front-rear direction. The reading sensor3S is located below the document support surface3A and the reading surface3B.

When the image scanner3reads an image of a document supported on the document support surface3A, the reading sensor3S reads the image of the document in a line in the front-rear direction, that is, in a main scanning direction, while moving rightward, that is, in a sub-scanning direction, from below the left edge of the document support surface3A by an operation of a scanning mechanism (not shown). When the reading sensor3S moves to a position below the right edge of the document support surface3A, the reading sensor3S finishes reading the image and returns to a standby position by the operation of the scanning mechanism (not shown).

When the conveyor4described later operates, the reading sensor3S moves to a stationary reading position below the reading surface3B by the operation of the scanning mechanism (not shown), and stop there.

As shown inFIG.1, the cover9is located above the main body8. The rear end of the cover9is connected to the rear end of the main body8via a hinge (not shown). The cover9is swingable about a swing axis X9extending in the left-right direction.

As shown inFIG.2, the cover9has a base member95made of resin. The lower surface of the base member95forms the bottom surface of the cover9. The bottom surface of the cover9has a size of capable of covering the entire upper surface of the main body8. The lower surface of the base member95of the cover9covers the document placed on the document support surface3A.

Although not shown, when a user swings the cover9upward and rearward about the swing axis X9, the cover9open the document support surface3A. In this state, the user places a document on the document support surface3A and takes out the document.

As shown inFIGS.1and2, the cover9has a supply tray91and a discharge tray92. The supply tray91and the discharge tray92are located at the right portion of the cover9.

The upper surface of the right portion of the base member95forms the discharge tray92. The supply tray91is located above the discharge tray92. The supply tray91supports sheets SH to be read in a stacked state.

In this embodiment, an object whose image is read using the document support surface3A is referred to as a document, and an object whose image is read while being conveyed by the conveyor4is described as a sheet SH. The document and the sheet SH may be substantially the same.

As shown inFIG.2, the cover9has the conveyor4and a conveyance guide30. The conveyor4and the conveyance guide30are located inside the left portion of the cover9.

The conveyor4includes a feed roller41, a separation roller42, a separation pad42A, a first conveyance roller pair43, and a second conveyance roller pair44, which are well known. The image scanning apparatus1also includes the sheet discharge device5that constitutes a part of the conveyor4.

The feed roller41faces the left end of the supply tray91from above. The separation roller42and the separation pad42A are located to the left of the feed roller41.

The first conveyance roller pair43and the second conveyance roller pair44are located at a side of the left side wall of the cover9. The first conveyance roller pair43is located at a higher position than the second conveyance roller pair44.

The sheet discharge device5is located above the left end of the discharge tray92. A specific configuration of the sheet discharge device5will be described in detail later.

The conveyance guide30has a first portion31, a second portion32, and a third portion33. The first portion31, the second portion32, and the third portion33are formed by parts of a plurality of chute members located inside the cover9, ribs protruding downward from the lower surface of the upper wall member of the cover9, and so on.

The first portion31is a guide that guides the sheet SH from the left end of the supply tray91to the first conveyance roller pair43.

The second portion32is a guide that guides the sheet SH from the second conveyance roller pair44toward the discharge tray92, that is, to the sheet discharge device5.

More specifically, the second portion32guides the sheet SH from the second conveyance roller pair44to the reading surface3B so as to be inclined downward, and then causes the sheet SH to pass over the reading surface3B, that is, above the reading sensor3S at the stationary reading position. After that, the second portion32guides the sheet SH to the sheet discharge device5so as to be inclined upward.

The base member95has a discharge guide96. The discharge guide96is located between the reading surface3B and the left end of the discharge tray92. The upper surface of the discharge guide96is inclined upward to the right from a position adjacent to the reading surface3B to reach a top portion96T. The upper surface of the discharge guide96defines, from below, a portion that guides the sheet SH in the second portion32so as to be inclined upward to the sheet discharge device5.

The third portion33is connected to the first portion31and the second portion32at the side of the left side wall of the cover9. The third portion33is a guide that guides the sheet SH from the first conveyance roller pair43to the second conveyance roller pair44so as to make a U-turn.

When the image scanner3reads images of the sheets SH supported by the supply tray91, the conveyor4conveys the sheets SH supported by the supply tray91one sheet at a time. The first portion31, the third portion33, and the second portion32of the conveyance guide30guide the conveyed sheet SH to pass above the reading sensor3S at the stationary reading position. Thereby, the reading sensor3S reads the image on the surface of the sheet SH. Thereafter, the sheet discharge device5discharges the sheet SH from which the image has been read toward the discharge tray92, and the discharge tray92supports the sheet SH.

<Configuration of Sheet Discharge Device>

As shown inFIGS.3to5, the sheet discharge device5has a drive shaft59, two discharge rollers50, a support shaft89, and two sets of follow rotation units6.

The center axis of the drive shaft59and an axis X1which is the center of the support shaft89are parallel to each other, and extend in the front-rear direction. The width direction of the sheet discharge device5is the front-rear direction parallel to the axis X1. In this embodiment, the front side is one side in the width direction, and the rear side is the other side in the width direction.

As shown inFIG.3, the drive shaft59is a steel round bar extending in the width direction above the top portion96T of the discharge guide96. Shaft support portions99A and99B located at the front and rear ends of the base member95rotatably support both ends of the drive shaft59in the width direction.

Although not shown, the conveyor4has a drive source and a transmission mechanism that transmits a driving force generated by the drive source to the drive shaft59. A gear59G constitutes a part of the transmission mechanism, and transmits the driving force to the drive shaft59to rotate the drive shaft59.

The drive shaft59holds the two discharge rollers50so as to be rotatable together. Each discharge roller50is separated from each other in the width direction. Each discharge roller50has the same configuration.

Each discharge roller50is made of rubber, more specifically, ethylene propylene diene rubber (EPDM). The outer circumference of each discharge roller50is a cylindrical surface extending in the width direction without steps or unevenness. Each discharge roller50is compressed and deformed by being pressed by a member harder than itself.

Each discharge roller50rotates integrally with the drive shaft59, and contacts the sheet SH passing through the top portion96T of the discharge guide96from above. Thereby, each discharge roller50applies a conveyance force to the sheet SH and discharges the sheet SH to the discharge tray92.

The discharge guide96has a support shaft accommodating portion96A, two spring accommodating portions96B, and two follow-rotation-unit accommodating portions96C.

The support shaft accommodating portion96A is a groove recessed downward from the top portion96T and extending in the width direction. Both ends of the support shaft accommodating portion96A in the width direction are located outside the discharge rollers50in the width direction.

Each spring accommodating portion96B is a bottomed hole that overlaps the support shaft accommodating portion96A at a position that is inside the discharge rollers50in the width direction and apart from each other in the width direction, and is recessed downward from the top portion96T. A compression coil spring89S is located inside each of the spring accommodating portions96B.

Each follow-rotation-unit accommodating portion96C is a recess that overlaps the support shaft accommodating portion96A below each discharge roller50and is recessed downward from the top portion96T.

The support shaft89is located within the support shaft accommodating portion96A. The support shaft89is a steel round bar that extends to near both ends in the width direction of the support shaft accommodating portion96A. The support shaft89extends around the axis X1. The compression coil spring89S urges the support shaft89upward such that the support shaft89moves toward the drive shaft59.

Each of the follow rotation units6is located below each discharge roller50and inside the follow-rotation-unit accommodating portion96C. Since each of the follow rotation units6has the same configuration, one of the follow rotation units6will be described, and the description of the other of the follow rotation units6will be omitted.

As shown inFIGS.4to7, the follow rotation unit6has a follow roller60, a holder80, and two rubber members7.

As shown inFIGS.6to10, the follow roller60is a member integrally having an anti-rotation protrusion64, a contact portion65, and an engagement portion66. The follow roller60is made of resin, more specifically polyacetal resin (POM). That is, the follow roller60is harder than the discharge roller50.

The follow roller60has a substantially cylindrical shape of which the center axis is the axis X1. An outer circumferential surface60S of the follow roller60is a cylindrical surface that extends in the width direction without steps or unevenness. The outer circumferential surface60S is an example of “outer circumference of the follow roller”. In a case where the surface of the follow roller60has steps or unevenness, the portion of the steps or unevenness farthest from the axis X1forms the outer circumference of the follow roller60.

As shown inFIG.8, an inner circumferential surface60T of the follow roller60is a cylindrical surface that extends in the width direction without steps or unevenness, except for the anti-rotation protrusion64, the contact portion65, and the engagement portion66.

As shown inFIG.5, a length W2of the follow roller60in the width direction is smaller than a length W1of the discharge roller50in the width direction. Ends50E of the discharge roller50at one side and the other side in the width direction are located outside of edges60E of the follow roller60at one side and the other side in the width direction, with respect to the width direction.

As shown inFIGS.8and10, the contact portion65is an inner flange that protrudes radially inward of the axis X1from the other end the inner circumferential surface60T in the width direction. The contact portion65has a substantially C shape with a part cut out as viewed from the direction of the axis X1. Hereinafter, a radial direction of the axis X1is simply referred to as “radial direction”.

The contact portion65has a contact surface65A. The contact surface65A is a surface facing one side in the width direction among the inner flange.

As shown inFIGS.8and9, the anti-rotation protrusion64protrudes radially inward from the inner circumferential surface60T of the follow roller60and extends in the width direction. The end of the anti-rotation protrusion64at the other side in the width direction is connected to the contact surface65A. As shown inFIG.9, the end of the anti-rotation protrusion64at one side in the width direction is separated from one end of the inner circumferential surface60T in the width direction by a distance greater than the thickness of a flange portion83described later.

As shown inFIGS.8and9, the engagement portion66is located on the inner circumferential surface60T of the follow roller60at a position away from the cutout portion of the contact portion65toward one side in in the width direction. The engagement portion66(engagement protrusion) is a claw-like protrusion protruding radially inward. As shown inFIG.9, the engagement portion66has a retainer surface66A and an inclined surface66B.

The retainer surface66A protrudes radially inward from the inner circumferential surface60T of the follow roller60and faces the other side in the width direction.

The inclined surface66B extends from the tip edge of the retainer surface66A so as to be inclined toward one side in the width direction and toward the inner circumferential surface60T radially.

As shown inFIGS.6,7,9and10, the holder80is a member having a shaft hole80H, a first holding portion81, and two second holding portions82that are formed integrally. The holder80is made of resin, more specifically polyacetal resin (POM).

The axis X1is the axial center of the shaft hole80H. The shaft hole80H is formed to penetrate the first holding portion81and the second holding portions82. Each second holding portion82is located outside the first holding portion81in the width direction.

As shown inFIGS.9and10, the support shaft89enters the shaft hole80H and holds the holder80. In this state, the holder80is rotatable about the axis X1relative to the support shaft89.

As shown inFIGS.6and7, the first holding portion81has two flange portions83and a contact protrusion86.

The flange portions83protrude radially outward in a flange shape from positions separated from each other in the width direction. The flange portion83at the other side in the width direction has an anti-rotation recess84and an inclined recess85.

The anti-rotation recess84is recessed radially inward from the outer circumferential edge of the flange portion83. The inclined recessed85is recessed radially inward from the outer circumferential edge of the flange portion83at a position opposite to the anti-rotation recess84with respect to the axis X1. The bottom surface (inclined surface) of the inclined recess85is inclined to be radially outward from the other side toward one side in the width direction.

The contact protrusion86is connected to the outer circumferential edge of the flange portion83at the other side in the width direction, and protrudes toward the other side in the width direction.

Each of the second holding portions82has a first cylinder82A and a second cylinder82B, each having a cylindrical shape. The second cylinder82B is located outside the first cylinder82A in the width direction.

The first cylinder82A has a smaller diameter than each flange portion83. The second cylinder82B has a smaller diameter than each flange portion83and a larger diameter than the first cylinder82A.

As shown inFIG.9, the holder80slides from one side to the other side in the width direction to enter the follow roller60. Thereby, each flange portion83fits the inner circumferential surface60T of the follow roller60, and the anti-rotation recess84fits the anti-rotation protrusion64.

At this time, in the follow roller60, as shown inFIG.10, the contact surface65A of the contact portion65contacts the contact protrusion86of the first holding portion81from the other side in the width direction. And, as shown inFIG.9, due to the inclined surface66B, the engagement portion66gets (climbs) over the inclined recess85of the flange portion83at the other side in the width direction, and the retaining surface66A contacts the flange portion83from one side in the width direction.

As a result, the first holding portion81holds the follow roller60from the inside. In this state, the follow roller60is integral with the holder80and is rotatable about the axis X1together with the holder80.

As shown inFIGS.6,7,9and10, each rubber member7is one member integrally having a paddle70and a groove (clearance portion)75. Each rubber member7is made of rubber, more specifically, ethylene propylene diene rubber (EPDM).

In other words, the paddle70and the groove75are softer than the follow roller60. Also, in this embodiment, the paddle70and the groove75are softer than the discharge roller50.

The rubber member7has a substantially cylindrical shape. The rubber member7includes a flange-shaped paddle70and a rubber member main body. The rubber member main body is continuous from the paddle70so as to be located closer to the follow roller60than the paddle70is, and forms the groove75. The paddle70is located outside the groove75in the width direction. The paddle70has a plurality of protrusions71and recesses72on the outer circumference of the flange shape. The protrusions71and the recesses72are alternately arranged in the circumferential direction of the axis X1. Hereinafter, the circumferential direction of the axis X1is simply referred to as “circumferential direction”.

As shown inFIG.7, the protrusion71protrudes farther radially outward than the outer circumferential surface60S of the follow roller60. That is, a distance L3between the tip of the protrusion71and the axis X1in the radial direction is greater than a distance L1between the outer circumferential surface60S of the follow roller60and the axis X1in the radial direction.

The recess72is recessed radially inward between two protrusions71adjacent to each other in the circumferential direction. A distance L2between the bottom of the recess72and the axis X1in the radial direction is smaller than the distance L1.

A distance L4between an outer circumferential surface of the groove75and the axis X1in the radial direction is smaller than the distances L1and L2. Thus, the groove75has a shape that is recessed one round toward the center in the radial direction from the follow roller60. In other words, the groove75has a groove-shaped bottom between the follow roller60and the paddle70.

The rubber member7has a substantially cylindrical shape having a through hole that is formed to penetrate in the width direction, and the through hole has two portions with different diameters. Of the through hole, a pressure contact hole7H is formed at a radially inner side of the groove75and a portion of the paddle70located at the inner side of the protrusions71and the recesses72in the width direction. Of the through hole, the outer side in the width direction of the pressure contact hole7H has a shape of a through hole having a diameter larger than that of the pressure contact hole7H. The through hole having the larger diameter has an inner circumferential surface70T. That is, the paddle70has the protrusions71and the recesses72on its outer circumference, and has the inner circumferential surface70T on its inner circumference.

As shown inFIGS.9and10, the second holding portion82of the holder80holds, from the inside, the paddle70and groove75of each rubber member7in a state where the first cylinder82A enters the pressure contact hole7H. In this state, the paddle70and the groove75rotate about the axis X1integrally with the holder80and the follow roller60.

The paddle70and the groove75are prevented from rotating relative to the holder80due to pressure contact between the first cylinder82A and the groove75and a part of the paddle70via the pressure contact hole7H. The second cylinder82B retains the paddle70and the groove75relative to the holder80.

As shown inFIG.11, the paddles70are located at one side and the other side of the follow roller60in the width direction.

The groove75at one side in the width direction is located between the edge60E of the follow roller60at one side in the width direction and the paddle70at one side in the width direction. Further, the groove75at one side in the width direction is located at the same position as the end50E of the discharge roller50at one side in the width direction.

The groove75at the other side in the width direction is located between the edge60E of the follow roller60at the other side in the width direction and the paddle70at the other side in the width direction. Further, the groove75at the other side in the width direction is located at the same position as the end50E of the discharge roller50at the other side in the width direction.

Each groove75is recessed farther radially inward than the outer circumferential surface60S of the follow roller60.

Note thatFIG.11exaggerates deformation of a portion of the discharge roller50that is pressed by the follow roller60.

As shown inFIGS.9and10, the inner circumferential surface70T of the protrusions71and the recesses72of the paddle70is separated radially outward from the second holding portion82. Ends80E of the holder80at one end and the other end in the width direction protrude farther outward in the width direction than the paddle70.

As shown inFIG.11, the follow roller60nips the sheet SH together with the discharge roller50and rotates following the discharge roller50. The protrusions71and the recesses72of the paddle70also rotate about the axis X1integrally with the follow roller60, and the protrusions71contact the sheet SH. Accordingly, when the trailing edge of the sheet SH enters the recess72of the paddle70, the protrusion71contacts the trailing edge and kicks out the sheet SH.

In the sheet discharge device5of the embodiment, as shown inFIG.11, the ends50E of the discharge roller50at one side and the other side in the width direction press the sheet SH toward each groove75at a position between the follow roller60and each paddle70. Here, the discharge roller50is softer than the follow roller60. Thus, the sheet discharge device5causes the sheet SH to warp such that portions of the sheet SH located outside the follow roller60in the width direction enter the grooves75and approach the protrusions71and the recesses72.

Thus, in the sheet discharge device5, it is unlikely that kicking of the trailing edge of the sheet SH by the protrusions71and the recesses72is weakened. As a result, the sheet discharge device5suppresses problems that the trailing edge of the sheet SH stays near the follow roller60, that the leading edge of the subsequent sheet SH slips under the trailing edge of the staying sheet SH to change the discharge order of the sheets SH, and that the subsequent sheet SH collides with the trailing edge of the staying sheet SH to cause damage or jamming of the sheet SH.

Thus, the sheet discharge device5of the embodiment suppresses discharge failures of the sheet SH. The same goes for the image scanning apparatus1of the embodiment including the sheet discharge device5.

In the sheet discharge device5, as shown inFIGS.9and10, the paddle70and the groove75are one member and are softer than the follow roller60. The holder80includes the first holding portion81that holds the follow roller60from the inside, and the second holding portion82located outside the first holding portion81in the width direction and holding the paddle70and the groove75from the inside. With this configuration, the paddle70and the groove75which are softer than the follow roller60are held by the second holding portion82of the holder80in a preferable manner. As a result, in the sheet discharge device5, it is unlikely that kicking of the trailing edge of the sheet SH by the protrusions71and the recesses72is weakened.

In the sheet discharge device5, the inner circumferential surface70T of the protrusions71and the recesses72of the paddle70is separated from the second holding portion82radially outward. With this configuration, the second holding portion82is unlikely to prevent deformation of the protrusion71and the recess72of the paddle70, and the protrusion71is easily deformed radially inward when pressed by the sheet SH. Thus, the sheet discharge device5prevents the contact pressure of the protrusions71against the sheet SH from becoming excessively large, and suppresses scraping of the protrusions71. As a result, the sheet discharge device5improves the durability of the paddle70.

In the sheet discharge device5, as shown inFIG.11, the ends80E of the holder80at one end and the other end in the width direction protrude farther outward in the width direction than the paddle70. With this configuration, the ends80E of the holder80at one end and the other end in the width direction contact a frame holding the support shaft89and so on, more specifically, the follow-rotation-unit accommodating portion96C of the base member95before the paddle70contacts the same. Thus, the sheet discharge device5suppresses scraping of a side surface of the paddle70. As a result, the sheet discharge device5improves the durability of the paddle70. Further, if the paddle70comes into contact with the frame holding the support shaft89and so on, the paddle70does not rotate and only the follow roller60rotates, which may weaken kicking of the trailing edge of the sheet SH. However, because the ends80E of the holder80at one end and the other end in the width direction protrude farther outward in the width direction than the paddle70, the paddle70is reliably rotated together with the follow roller60.

In the sheet discharge device5, as shown inFIG.7, the distance L2between the bottom of the recess72and the axis X1in the radial direction is smaller than the distance L1between the outer circumferential surface60S of the follow roller60and the axis X1in the radial direction. With this configuration, because the recesses72are recessed farther radially inward than the outer circumferential surface60S of the follow roller60, the deformability of the protrusion71is ensured by maximizing the distance between the tip of the protrusion71and the bottom of the recess72without increasing the protrusion amount of the protrusion71. As a result, the sheet discharge device5suppresses the occurrence of impact noise and contact marks when the sheet SH contacts the protrusion71, compared with a case where the protrusion amount of the protrusion71is increased.

In the sheet discharge device5, as shown inFIGS.6and9, the flange portion83at the other side in the width direction has the anti-rotation recess84and the inclined recess85. The follow roller60has the anti-rotation protrusion64. The holder80slides from one side to the other side in the width direction to enter the follow roller60. Thereby, each flange portion83fits the inner circumferential surface60T of the follow roller60, and the anti-rotation recess84fits the anti-rotation protrusion64. With this configuration, the follow roller60is attached to the holder80and the rotation of the follow roller60relative to the holder80is prevented with a single action.

In the sheet discharge device5, as shown inFIGS.8and10, the follow roller60has the contact portion65and the engagement portion66. The holder80slides from one side to the other side in the width direction to enter the follow roller60. Thereby, in the follow roller60, as shown inFIG.10, the contact surface65A of the contact portion65contacts the first holding portion81from the other side in the width direction. And, as shown inFIG.9, due to the inclined surface66B, the engagement portion66gets one of the flange portion83, and the retaining surface66A contacts the flange portion83from one side in the width direction. With this configuration, the follow roller60is retained relative to the holder80with a single action.

In the sheet discharge device5, the second holding portion82includes the first cylinder82A in contact with the groove75and a part of the paddle70via the pressure contact hole7H, and the second cylinder82B located outside the first cylinder82A in the width direction and having a larger diameter than the first cylinder82A. With this configuration, the shape of the second holding portion82is simplified, and the paddle70and the groove75, which are one member, are retained relative to the holder80by the second cylinder82B.

In the sheet discharge device5, the discharge roller50is made of rubber, and the follow roller60is made of resin. If the discharge roller50and the follow roller60are made of rubber, there is a possibility that an oil component and so on contained in the rubber will migrate from the follow roller60to the discharge roller50and change the outer diameter of the discharge roller50. Then, when the outer diameter of the discharge roller50changes, the conveyance speed of the sheet SH by the discharge roller50fluctuates, and the image reading quality by the reading sensor3S may deteriorate. In this regard, the sheet discharge device5and the image scanning apparatus1of the embodiment suppresses changes in the outer diameter of the discharge roller50due to the above configuration, and deterioration of the reading quality is suppressed.

In the sheet discharge device5, as shown inFIG.5, the length W2of the follow roller60in the width direction is smaller than the length W1of the discharge roller50in the width direction. As shown inFIG.11, each paddle70is located at one side and the other side of the follow roller60in the width direction. Each groove75is located between the follow roller60and the paddle70at one side in the width direction and between the follow roller60and the paddle70at the other side in the width direction. With this configuration, it is unlikely that kicking of the trailing edge of the sheet SH by the protrusions71and the recesses72is weakened.

In the embodiment, the paddle70and the groove75are one member (one piece), but the present disclosure is not limited to this configuration. For example, the follow roller and the groove may be one member. Further, the groove may be a member different from the follow roller and the paddle, for example, a part of the holder80in the embodiment. Further, the follow roller, the paddle and the groove may be one member.

In the embodiment, the discharge roller50is made of EPDM, but the present disclosure is not limited to this configuration. For example, the discharge roller may be made of rubber different from EPDM, or may be made of resin that is softer than the follow roller.

In the embodiment, the follow roller60is made of POM, but the present disclosure is not limited to this configuration. For example, the follow roller may be made of resin or rubber different from POM, provided that the follow roller is harder than the discharge roller.

In the embodiment, two sets of the paddles70and the grooves75are located at one side and the other side of the follow roller60in the width direction, but the present disclosure is not limited to this configuration. For example, the paddle and the groove may be provided at only one side of the follow roller in the width direction.

In the embodiment, the sheet discharge device of the present disclosure is embodied as the sheet discharge device5included in the image scanning apparatus1, but the present disclosure is not limited to this configuration. For example, the present disclosure may be applied to a sheet discharge device included in an image forming apparatus that forms an image on a sheet. Further, the present disclosure may be applied to a sheet discharge device of an image forming apparatus or an image scanner in a multifunction peripheral (MFP) including the image scanner at the upper side of the image forming apparatus.

In the embodiment, regarding the recess72of the paddle70, the distance L2between the bottom of the recess72and the axis X1in the radial direction is smaller than the distance L1between the outer circumferential surface60S of the follow roller60and the axis X1in the radial direction. The present disclosure is not limited to this configuration. For example, the distance L2may be greater than the distance L1.