WO2004099048A1

WO2004099048A1 - Sheet-conveying mechanism

Info

Publication number: WO2004099048A1
Application number: PCT/JP2004/004218
Authority: WO
Inventors: Toshihiko Seike; Akira Kohno; Masatsugu Ohishi; Takashi Hori; Hideshi Izumi; Tomohiko Fujii
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2003-04-02
Filing date: 2004-03-25
Publication date: 2004-11-18
Also published as: CN1767990A; US20060180989A1; CN100439222C; JP2004307087A; JP4197449B2

Abstract

A sheet-conveying guide is constructed from helical torsion springs (X). An end portion (B5) of one arm portion (B4) of each helical torsion spring supports a rotating shaft of a follower roller (R32) and applies an elastic force to the follower roller (R32). The arm portion (B4) formed in a curved shape causes a rotating roller (R31) to guide a sheet material in an early stage of the roller (R31). A coil portion (B1) of a helical coil spring (X) and an end portion (B3) of the other arm portion (B2) are fixed. Follower rollers (R32) are arranged parallel to a shaft (R31a) of the rotating roller, and a helical torsion spring (X) is provided at each follower roller (R32). An elastic force set for each helical torsion spring (X) is made to be strongest for a follower roller (R32) at a predetermined standard position and to be weaker for a follower roller (R32) away from the roller (R32) at the predetermined standard position.

Description

Description Sheet transport mechanism

Technical field

The present invention relates to a sheet provided with a rotating roller provided in an image forming apparatus or the like, an oscillating member elastically biased against the rotating roller, and a sheet transport guide for guiding the transport of a sheet material transported therebetween. It relates to a transport mechanism. Background art

An image forming apparatus or the like is provided with a rotating roller that is driven to rotate and a driven roller or a separating pad that is a resiliently oscillating member to convey a sheet material such as recording paper. By passing the sheet material between the rotating roller and the swinging member, the sheet material is conveyed by the rotating force of the rotating roller. Further, a sheet material is guided between the rotating roller and the swinging member, or is conveyed from between the rotating roller and the swinging member, to a front stage and a Z stage or a rear stage of the rotating roller. A sheet transport guide is provided to guide the sheet material to the next transport path.

FIG. 4 is a schematic cross-sectional view illustrating a configuration example of a conventional sheet conveyance guide. The sheet material S set in a predetermined sheet feeding section 1 is sent out from the sheet feeding section 1 by a sheet feeding roller R1, and is separated by a separating roller R2 (an example of the rotating roller) and a spring. Guided between the elastically biased separating pad 2 (friction pad). When a plurality of sheet materials S are discharged by the paper feed roller R1, a frictional force acting between the separating pad 2 and the sheet material S and between the plurality of sheet materials S, Due to the difference between the frictional force acting between the roller R2 and the sheet material S in contact with the roller R2, the sheet materials S are separated one by one and conveyed to the subsequent stage. At this time, the separating pad 2 swings due to the difference in thickness of the sheet material S (an example of a swinging member). The sheet material S that has passed through the separating roller R 2 and the separating pad 2 is guided by a sheet conveying guide G at a stage subsequent to the separating roller R 2, and an image is transferred to the sheet material S. The sheet material S is guided in the direction of the pair of idle rollers R3 for transporting the sheet material S to the transfer portion.

The idle roller pair R 3 includes an idle roller R 31, which is rotationally driven, and a driven roller R 32, which is elastically urged by a spring or the like and driven to rotate, and is driven by the thickness of the sheet material S. The driven roller R32 swings (an example of a swinging member). The sheet transport guide G is made of sheet metal, resin, or the like, and is formed so as to guide the sheet material S between the idle roller R 31 and the driven roller 32 before the idle roller R 31. .

Here, since the separating pad 2 and the driven opening roller R 32 (hereinafter referred to collectively as a swinging member) swing, the sheet transport guide G and the above-mentioned sheet transport guide G are not interfered with these movements. Predetermined gaps 4 and 5 are provided between the rocking members.

However, in recent years, as the size of the apparatus has been reduced, the sheet conveying guide is configured to change the direction of the sheet material with a small radius of curvature, so that the sheet material is swung in the gap with the swing member. There is a problem that a jam easily occurs due to a collision between the moving member and the rotating roller. In the example shown in Fig. 4, the gap 5 is particularly small in radius of curvature, and jams are likely to occur.

On the other hand, Japanese Patent Application Laid-Open No. H06-92505 proposes a configuration in which a sheet material is guided by a film member arranged near a pinch roller (an example of a rotating roller). However, it was difficult to change the direction with a small radius of curvature.

An object of the present invention is to guide a sheet material smoothly without a gap before and after a rotating roller and an oscillating member elastically biased by the rotating roller, and to change the direction of a sheet material with a small radius of curvature. An object of the present invention is to provide a sheet conveyance guide that can respond. Disclosure of the invention

The present invention provides a rotating roller, a swing member biased to the rotating roller, and a step of transporting a sheet material conveyed between the rotating roller and the swing member before the rotating roller. And / or a sheet conveyance guide made of an elastic member, a part of which is connected to the oscillating member, and wherein the sheet conveyance guide is provided with the elastic force of the sheet conveyance guide to the oscillating member. The oscillating member is elastically urged against the rotating roller.

For example, the elastic member is a torsion coil panel, and the sheet member is guided by an arm of the torsion coil panel.

Examples of the swing member include a driven roller that is driven to rotate by the rotation roller, and a separation pad that separates and transports the sheet material one by one.

Accordingly, a portion for guiding the sheet material (eg, an arm portion of the torsion coil panel) extends to the swinging member facing the rotary roller. There is no gap between the swinging member and the sheet material, and the sheet material can be smoothly transported (guided). Further, if the shape of the elastic member (that is, the sheet conveyance guide) is adjusted to the radius of curvature necessary for changing the direction of the sheet material, it is possible to cope with a conveyance path having a small radius of curvature.

Further, as a configuration of the sheet conveyance guide using the torsion coil spring, for example, a configuration in which the swinging member is supported by a coil portion or one arm portion of the torsion coil panel is considered.

In this case, a plurality of the swing members may be arranged in a direction substantially parallel to the axis of the rotating roller, and the sheet conveyance guide may be formed of the elastic member provided for each of the swing members.

As a result, in the width direction of the sheet material (ie, in a direction substantially parallel to the axis of the rotating roller), a guide such as an arm portion of the torsion coil panel that guides the sheet material is provided. Since a plurality of sheet parts are arranged, and if the arrangement interval is set to a suitably small interval, stable guiding can be performed even when the sheet material size (width) is large.

Further, in this case, the elastic biasing force of each of the elastic members is configured to be strongest with respect to the swing member at a predetermined reference position and weaker with respect to the swing member located at a distance from the reference position. Are preferred.

Thereby, when the swinging member is the driven roller, it is possible to prevent the sheet material from being sheared. The reference position is, for example, the center or one end of the rotating roller in the axial direction. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic sectional view of a sheet conveying mechanism according to an embodiment of the present invention. Figure 2 is a schematic front view of the sheet conveyance guide X and a graph showing the distribution of the spring force of the torsion coil spring.

FIG. 3 is a schematic sectional view of a sheet conveying mechanism according to another embodiment of the present invention. Fig. 4 is a schematic sectional view of a conventional sheet conveyance guide.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.

FIG. 1 is a schematic sectional view of a sheet conveying mechanism according to an embodiment of the present invention, and FIG. 2 is a schematic front view of the sheet conveying mechanism and a graph showing a distribution of spring pressure of a torsion coil spring.

The sheet transport mechanism is applied to a sheet feeding unit of an image forming apparatus. This sheet transport mechanism includes a sheet transport guide X. The sheet conveyance guide X is composed of a torsion coil panel (hereinafter referred to as a torsion coil spring X). A sheet member s such as recording paper conveyed from a predetermined paper feed unit 1 is provided in front of an idle roller pair R 3 for conveying the sheet material s to a transfer unit 3 for transferring a toner image to the sheet material S It is.

The torsion coil spring X has a coil portion B1 and one end portion B3 of one arm portion B2 fixed to a frame of the image forming apparatus main body, and an end portion B5 of the other arm portion B4. The idler roller pair R 3 supports the rotating shaft of a driven roller R 32 constituting the idle roller pair R 3. As a result, the driven roller R32 is biased by an elastic force of the torsion coil spring X toward an idler roller R31 (an example of the rotary roller) constituting the idle roller pair R3. You. Further, the arm portion B4 is formed to be curved along the conveyance path of the sheet material S.

The sheet material S set in the sheet feeding section 1 is sent out from the sheet feeding section 1 by a sheet feeding roller R1 in the same manner as the conventional sheet material shown in FIG. On the other hand, the sheet material S is separated one by one by the separating pad 2 (friction pad) elastically urged by a panel or the like, and is conveyed to the subsequent stage. The separating pad 2 is rotatably supported on a predetermined rotating shaft 2a, and the separating pad 2 swings (rotates) due to a difference in thickness of the sheet material S passing therethrough.

The sheet material S that has passed through the separating roller R2 and the separating pad 2 is guided by the arm portion B4 of the torsion coil spring X, and is guided in the direction of the idle roller pair R3.

Here, the driven roller R32, which constitutes one of the idle roller pair R3, is moved relative to the idle roller R31 by the end B5 of the arm portion B4 by the elastic force of the torsion coil spring X. The driven roller R32 swings due to the thickness of the sheet material S passing therethrough because of the elastic biasing (an example of a swinging member).

With such a configuration, the torsion coil spring for guiding the sheet material S is provided. Since the arm portion B4 of X extends to the driven roller R32, there is no gap between the portion (B4) for guiding the sheet material S and the driven roller R32, The sheet material S can be smoothly transported (guided). Further, by making the shape of the arm portion B4 a curved shape that matches the radius of curvature necessary for changing the direction of the sheet material, it is possible to cope with a conveyance path having a small radius of curvature.

Fig. 2 is a schematic front view of the sheet transport guide X (Fig. 2A) and a graph showing the distribution of the panel pressure of the torsion coil panel (Figs. 2B and C). As shown in FIG. 2A, a plurality of the driven rollers R32 are arranged in a direction substantially parallel to the axis R31a of the idle roller R31 (five in FIG. 2). The end of the arm portion B4 of the torsion coil spring X is attached to the shaft of each of the driven rollers R32, where the torsion coil spring X is provided for each of the rollers R32. Holder R 30 is attached to

With such a configuration, the arm portion R of the torsion coil panel that guides the sheet material S in the width direction of the sheet material S (ie, a direction substantially parallel to the axis R31a of the idle port roller R31). 4 (not shown in Fig. 2) are arranged in a plural number. If the arrangement interval is set to an appropriately small interval, even if the size (width) of the sheet material S is large, it is stable. Can guide.

Here, the elastic force (spring pressure) set for each of the plurality of torsion coil panels X, that is, the 弹 biasing force from the driven roller R32 to the idle roller R31, is shown in the panel pressure distribution graph of FIG. 2B. As shown in the figure, the configuration is such that it is strongest for the driven roller R32 at a predetermined reference position P0, and weaker for the driven roller R32 at a position distant from the reference position P0. Have been.

As a result, the conveying force transmitted from the idler R 31 to the sheet material S increases in the direction in which the sheet material S is stretched (in the panel pressure distribution shown in FIG. 2B, This acts in the direction from the center of the shaft R31a of the idle roller R31 to the outside of the shaft R31a, so that it is possible to prevent the sheet material from being sheared.

The torsional force (panel pressure) set for each of the torsion coil panels X is set (adjusted) by the wire diameter, opening angle, the number of turns of the coil portion B1, the wire material (type), etc., in the torsion coil spring X. ) do it. Further, in FIG. 2B, the substantially central portion of the shaft R31a of the idle roller R31 is set to the reference position P0, and the panel pressure becomes weaker as the position is further away from both sides. However, the present invention is not limited to this. For example, as shown in FIG. 2C, the vicinity of one end of the shaft R31a of the idle roller R31 is set to the reference position P0. 3 It is also conceivable to adopt a configuration in which the panel pressure is reduced as the position becomes more distant in the opposite direction. This reference position P 0 is, for example, where a sheet material S of different size (width) can be conveyed, regardless of the size of the sheet material S being conveyed, the position where the sheet material S always passes. It is conceivable that

Next, another embodiment of the present invention will be described with reference to FIG.

In FIG. 3, the sheet conveying mechanism of the present invention is applied to a sheet material guide at a stage subsequent to the separating roller 2.

The sheet conveyance guide XI included in the sheet conveyance mechanism is composed of a torsion coil panel (hereinafter, referred to as a torsion coil spring X1), and one end B 2 ′ of the arm B 2 ′ is a frame of the image forming apparatus main body. And the other end B 5 ′ of the arm B 4 ′ is also fixed to the frame of the main body of the image forming apparatus. It is configured to be fixed to the guide section 6 at the subsequent stage, and to support the vicinity of the turning tip of the separating pad 2 by the coil section B 1 ′.

Thus, the separating pad 2 (an example of the swinging member) is elastically urged against the separating roller R 2 (an example of the rotary roller) by the elastic force of the torsion coil spring X1. With such a configuration, the arm portion B 4 ′ of the torsion coil spring X straddles between the discriminating pad 2 and the guide portion 6 at the subsequent stage, so that the arm portion B 4 ′ is connected to the discriminating pad 2. It serves as a guide that fills the gap between the guide section 6 and the sheet material, and enables smooth conveyance (guide) of the sheet material. Further, in the above embodiment, the torsion coil panel is used as the elastic member which also serves as the elastic urging member of the rocking member (the driven roller or the separating pad) and the guide members before and after the elastic member. Other metal members or the like that can obtain a high elastic biasing force may be used.

As described above, according to the present invention, the elastic member such as the torsion coil panel serves as the elastic urging force applying member of the swing member with respect to the rotating port and the guide member of the sheet material before and after the rotating roller. Since the part that guides the sheet material (such as the arm of the torsion coil panel) extends to the swing member, there is no gap between the part that guides the sheet material and the swing member. The material can be smoothly transported (guided). Furthermore, if the shape of the flexible member is adjusted to the radius of curvature necessary for changing the direction of the sheet material, it is possible to support a conveyance path with a small radius of curvature.

The description of the above embodiments is illustrative in all aspects and should not be construed as limiting. The scope of the present invention is defined by the terms of the claims, rather than the embodiments described above. Further, it is intended that the scope of the present invention include all modifications within the meaning and scope equivalent to the claims. Industrial potential

INDUSTRIAL APPLICABILITY The present invention can be applied to a paper feeding unit and a paper discharging unit of an apparatus that conveys and outputs paper, such as an image forming apparatus, a printer, and a facsimile.

Claims

The scope of the claims

(1) a rotating roller, a swing member elastically urged by the rotating roller, and a sheet material conveyed through the space between the rotating roller and the swing member. A sheet conveying guide made of an elastic member guided at Z or a subsequent stage, and a part of the sheet conveying guide is connected to the oscillating member, and the elastic force of the sheet conveying guide is applied to the oscillating member. A sheet conveying mechanism for elastically urging the swing member with respect to the sheet conveying mechanism.

(2) The sheet conveying mechanism according to claim 1, wherein the elastic member is a torsion coil panel, and the sheet material is guided by an arm of the torsion coil panel.

(3) The sheet conveying device according to claim 2, wherein the swing member is a driven roller that is driven to rotate by the rotation roller.

(4) The sheet transport mechanism according to claim 3, wherein the driven roller is supported by one arm of the torsion coil panel.

(5) The sheet transport mechanism according to claim 2, wherein the swing member is a separation pad that separates and transports the sheet material one by one.

(6) The sheet conveying mechanism according to claim 5, wherein the separation pad is supported by a coil portion of the torsion coil panel.

(7) The sheet transport mechanism according to claim 4, wherein a plurality of the swing members are arranged in a direction substantially parallel to an axis of the rotating roller, and the sheet transport guide is provided for each of the swing members.

(8) The magnitude of the elastic force applied to each of the sheet transport guides is stronger than that of the sheet transport guide at a predetermined reference position, and is greater than that of the sheet transport guide located away from the reference position. 8. The sheet transport mechanism according to claim 7, wherein the sheet transport mechanism is set to be weaker than that.

(9) The farther the sheet conveyance guide is from the reference position, 8. The sheet conveying mechanism according to claim 7, wherein the force to be set on the sheet conveying guide is set to be weak.

(10) The sheet transport mechanism according to (8), wherein a plurality of the oscillating members are arranged in a direction substantially parallel to the axis of the rotating roller, and a substantially center position thereof is the reference position.

(11) In a state where the plurality of swing members are arranged in a direction substantially parallel to the axis of the rotating roller, the position of one end of both ends is the reference position. The sheet conveying mechanism described in the above.