JP5760329B2 - Sheet feeding device - Google Patents

Description

  The present invention relates to a sheet feeding apparatus that separates and feeds a stack of stacked sheets one by one.

  2. Description of the Related Art Conventionally, a sheet feeding device that separates and feeds transfer sheets and documents one by one is used for a paper feeding unit of various image forming apparatuses and a paper feeding unit of a document reading device. As such a sheet feeding device, a feeding rotating body that rotates in a sheet feeding direction, a separation holder that supports a friction member that forms a nip in contact with the feeding rotating body, and the separation holder is rotatable. In addition, there is known one having a holding frame body that is detachably mounted and an elastic member that presses the friction member in a direction in which the friction member abuts against the feeding rotating body via the separation holder.

  In this type of sheet feeding apparatus, if the separation pad, which is a friction member, is worn due to use over time, multiple feeding occurs frequently, so the separation pad must be replaced. The replacement of the separation pad is usually performed by an expert such as a service person. However, it is quite difficult to place the separation pad in the correct position and posture, and good separation performance is obtained if the separation pad is displaced. Cannot be secured. In view of this, Patent Documents 1 and 2 describe an apparatus that allows a general user to easily replace a separation pad.

  In Patent Document 1, a holding member that integrally holds the separation pad and the separation pressure spring is detachably attached to the apparatus main body, and when replacing the separation pad, the holding member is taken out from the apparatus main body, A sheet feeding apparatus is disclosed in which a separation pad is removed from the sheet feeding device. Patent Document 2 discloses an insertion guide for guiding the insertion of the separation unit into the opening from the sheet conveying rotation member side, and a cover provided in the separation unit that is guided by the insertion guide and inserted into the opening. The separation unit is attached to and detached from the sheet conveying rotation member side by providing a position restriction part that restricts the restriction part and positions the separation unit at a position where the separation unit should be accommodated in the opening. A sheet feeding device that can be made to be disclosed is disclosed.

  However, in Patent Document 1, it is necessary to remove even the separation unit holding portion for replacement of the separation pad, so that compared to Patent Document 2, extra work is required for the replacement work. Furthermore, since the separation unit and the separation unit holding portion are fixed by the support shaft and the hole, there is a risk that the support shaft may be broken when a person who is not used to the replacement work performs the replacement. . Further, in the case of Patent Document 2, since the spring for pressing the separation pad against the sheet conveying rotation member cannot be easily replaced, it is unnecessary when the spring is removed at the time of spring replacement or separation pad replacement. There is a problem that it is necessary to perform disassembly work.

  In view of the above-described conventional problems, an object of the present invention is to provide a sheet feeding apparatus that can replace the friction member of the separation unit with a simple operation.

In order to solve the above-described problems, the present invention provides a feeding rotating body that rotates in a sheet feeding direction, a separation holder that supports a friction member that forms a nip in contact with the feeding rotating body, and the separation In a sheet feeding apparatus comprising: a holding frame that is rotatably and detachably mounted on a holder; and an elastic member that presses the friction member in a direction to contact the feeding rotating body via the separation holder. and regulating means for regulating against the rotation of the separation holder the pressing force of the elastic member, and a receiving portion for receiving one end of said elastic member, wherein the receiving portion is recessed portion to which one end of the elastic member is guided The other end of the elastic member presses the separation holder outside the recess , and the restricting means includes a protrusion formed on the separation holder and the rotation locus of the protrusion Provided on the holding frame and positioned outside the recess It proposes a sheet feeding apparatus, characterized in that composed of the stopper convex shape.

The present invention is the separation holder detachably can be ing and is positioned at an angle with respect to the holding frame. The angle from the holding frame body that enables the attachment / detachment is θ1, the angle from the holding frame body where the friction member abuts on the feeding rotating body is θ2, and the angle from the holding frame body that the regulating means regulates is θ. Then, it is advantageous that θ2 <θ <θ1 is set.

  Further, according to the present invention, it is advantageous that the restricting means is composed of a convex portion formed on the separation holder and a stopper provided on the holding frame body within the rotation locus of the convex portion.

Still further, according to the present invention, it is advantageous that the protruding portion gets over the stopper when the separation holder applies a force greater than a certain elastic force of the elastic member.

  According to the present invention, the replacement work of the friction member is simplified, and the separation holder is blown off by the action of the elastic member when the feed rotating body is separated from the separation holder by replacement of the friction member at the time of replacement. Is prevented. Furthermore, since the installation and setting of the elastic member is easy, anyone can replace the friction member.

1 is an overall schematic diagram showing an automatic document feeder using a sheet feeding device according to the present invention. FIG. 6 is a perspective view showing a separation unit of the sheet feeding apparatus according to the present invention. Is a perspective view of the separation unit from different directions Figure 2. It is a perspective view which shows the attachment method of the elastic member which presses a separation unit to a feed rotary body. (A), (b), (c) is the upper view of the receiving part which receives the other end of the elastic member of FIG. 4, a side view, and sectional drawing. It is a figure which shows the control means which controls rotation of a separation holder by interference of the convex part of a base part, and the convex part of a separation holder from the pressing force of an elastic member. (A), (b), (c), (d) is a figure which shows the assembly | attachment method of assembling | attaching a separation unit to a base part. It is a figure which shows the attachment state and angle to the holding | maintenance frame of a separation unit. It is a figure which shows the regulation means which regulates rotation of a separation holder by the interference of the axis | shaft of a separation holder, and the convex part in the bearing by the side of a base part from the pressing force of an elastic member. (A), (b) is a figure which shows the control means which controls rotation of a separation holder by interference of the friction part and base part which were attached to the separation holder from the pressing force of the elastic member. (A), (b) is a figure which shows the regulation means which regulates rotation of a separation holder by interference of the friction part attached to the separation holder and the base part from the pressing force of an elastic member.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an overall schematic view showing a document reading apparatus provided with a sheet feeding apparatus according to the present invention.

In FIG. 1, a document reading apparatus 1 conveys a bundle of documents stacked on a document tray 2 between a separation unit 4 that is a sheet feeding device and a separation roller 5 by a pickup roller 3 . Then the separation nip between the separation unit 4 the separation roller 5, have given separating action to feed only the uppermost document to the document called the pickup roller 3. The top of the original document separated one by separation nip is conveyed to between the pullout roller 6a and the driven roller 6b by the rotation of the separation roller 5 is held to the pull-out roller 6. Although the conveyance speed of the pull-out roller 6 is set to be higher than the conveyance speed of the separation roller 5, a torque limiter (not shown) is attached to the separation roller 5 . For this reason, after the original reaches the pull-out roller 6, the accompanying operation can be performed at the conveyance speed of the pull-out roller 6.

The document that has reached the pull-out roller 6 is conveyed along the conveyance path to the image reading unit between the background plate 8 and the image reading device 9 via the pre-reading roller 7a and the driven roller 7b , and the image is read. Is called. In the case of single-sided reading, the original that has passed through the image reading unit is sent to the paper discharge tray 13 via the paper discharge roller 10a and its driven roller 10b. For double-sided reading, branching pawl 11 moves, the document from between the discharge roller 10a and the follower roller 10b to the reversing roller 12a and the follower roller 12b is Ru is conveyed. Thereafter, the sheet is conveyed to the pre-reading roller 7 via the sheet discharge roller 10a and the driven roller 10c, and an image is read in the same manner as in single-sided reading. However, if the original is sent out to the paper discharge tray 13 as it is after the back side image is read, the setting direction of the front and back of the original is opposite to that when the original is set on the original tray 2, and therefore the path transported at the time of double-side reading again Then, the original is sent out to the paper discharge tray 13.

2 and 3 are a front perspective view and a rear perspective view showing the separation unit 4 of the sheet feeding apparatus.
2 and 3, the separation unit 4 of this example includes a base 40 integrally or fixed to a machine frame of the apparatus main body, and a separation holder 41 to which a friction member as a separation pad 42 is attached by sticking or the like. have. Further, the separation unit 4 includes an elastic member as a pressing spring 43 that presses the separation holder 41 toward the separation roller 5 (shown in FIG. 1). In order to attach the separation holder 41 to the base part 40 in a rotatable and detachable manner, a bearing 44 having a notch 45 formed in the base part 40 is provided. In the case of this example, the bearing 44 is provided on one end side of the base portion 40 and separately on the left and right sides. The notch portion 45 is the top portion of the bearing 44 and the notch direction is the separation holder 41 . It is formed in the axial direction of the rotation fulcrum. On the other hand, the shaft 46 integrally connected by the connection part 46a is provided in the one end side of the separation holder 41, The cross-sectional shape of the shaft 46 is formed in the track shape (oval shape). The shaft 46 is set so that the short width of the track shape is set slightly smaller than the width of the notch 45, and the long width of the track shape is slidably in contact with the inner peripheral wall of the bearing 44. Is set to almost match. The entire shape of the separation holder 41 is curved in an arc shape, and a separation pad 42 is attached to the curved convex surface side by sticking or the like. The base part 40 and the separation holder 41 are each made of plastic resin.

  Further, the pressing spring 43 is disposed between the separation holder 41 and the base portion 40, and the assembly method is a cylinder formed at one end on the back side of the curved surface of the separation holder 41 as shown in FIG. It fits in the protrusion 47 of a shape. At this time, when the pressing spring 43 is pushed into the protrusion 47 by using the pressing spring 43 having an inner diameter slightly smaller than the diameter of the protrusion 47 of the separation holder 41, for example, about 0.1 mm, the tightening force of the inserted spring itself Thus, the spring is held by the separation holder 41. Note that the pressing spring 43 is a coil spring, and even if one end is fitted into the protrusion 47 and the other end, which is a free end, is positioned upward as shown in FIG. 4, the posture is broken by its own weight (the axis is bent). Has almost no elastic force.

  On the other hand, the base portion 40 is provided with a receiving portion 48 that receives the other end of the pressing spring 43. As shown in FIG. 5, the receiving portion 48 of this example is formed with a circular hollow portion 49 having a diameter substantially equal to the diameter of the pressing spring 43 at the center thereof, and a mortar guide portion that guides the pressing spring 43 to the hollow portion 49. 50 is provided. The mortar guide portion 50 does not need to be provided on the entire circumference of the recess portion 49, and the side farther from the bearing 44 where the other end of the pressing spring 43 is easily contacted when the separation holder 41 is mounted on the base portion 40 as will be described later. It is provided for the semicircle.

  The separation unit 4 is provided with restriction means for restricting the movement of the separation holder 41 against the pressing force of the pressing spring 43. In the embodiment shown in FIG. 2, FIG. 3 and FIG. 6, the restricting means is composed of a convex stopper 51 provided on the base part 40 and a convex part 52 provided on the separation holder 41. The convex portion 52 of the separation holder 41 is provided on the connecting shaft portion 44a between the left and right shafts 46. The working surface that contacts the stopper 51 is formed on a plane orthogonal to the axis, and the opposite surface gradually increases in thickness. It is formed in such a curved surface.

An assembling method for assembling the separation holder 41 to the base 40 configured as described above will be described with reference to FIG.
One end of the pressing spring 43 is fitted into the protrusion 47 in advance in the separation holder 41. When the separation holder 41 is assembled to the base portion 40, the longitudinal direction of the track-shaped shaft 46 is aligned with the position of the notch portion 45 of the bearing 44 as shown in FIG. In this example, the notch 45 is formed in the portion directly above the bearing 44, so that the longitudinal direction of the track-shaped shaft 46 is perpendicular to the base 40 as shown in FIG. The left and right shafts 46 are inserted into the left and right bearings 44, respectively. After the insertion, as shown in FIG. 7C, when the separation holder 41 is rotated counterclockwise about the shaft 46, the convex portion 52 provided on the separation holder 41 gets over the stopper 51. At this time, although resistance against overcoming rotation is received, the convex portion 52 provided in the separation holder 41 is formed in a shape that gradually increases in diameter, and thus can be overcome relatively smoothly. Thus, the separation holder 41 with the convex portion 52 overcoming the stopper 51 further rotates, so that the other end (free end) of the pressing spring 43 hits the mortar guide portion 50 of the receiving portion 48 and is guided to the recess portion 49. It fits into the recess 49 . Thereby, as shown in FIG.7 (d), the assembly | attachment to the base part 40 of the separation holder 41 is completed.

  As described above, the assembly of the separation holder 41 to the base unit 40 can be performed by a very simple operation, and the pressing spring 43 can be easily attached and the spring force does not need to be adjusted. It can be done easily. The contact between the convex portion 52 and the stopper 51 cannot be overcome by the force of the pressing spring 43, but the convex portion can be overcome without causing damage or the like by applying an appropriate large force by the operator. The material and contact width of 52 and stopper 51 are set as appropriate. Incidentally, the convex portion 52 and the stopper 51 are made of a plastic resin material. In this example, the base portion 40 provided integrally with the stopper 51 is the FR-ABS resin, and the separation holder 41 provided integrally with the convex portion 52 is provided. It is made from POM (polyacetal resin).

Separation unit 4 assembled in this way, the separation pad 42 of the separation holder 41 but hits the separation roller 5, the separation pressure at this time is given by the pressing spring 43. For this reason, when the separation roller 5 is retracted or removed due to replacement of the separation holder 41 or the like, the separation holder 41 may be blown by the action of the pressing spring 43. Therefore, as shown in FIG. 8, the angle formed between the surface of the base portion 40 and the separation holder 41 when contacting the separation roller 5 is θ2, and the surface of the base portion 40 and the convex portion 52 hit the stopper 51. The stopper 51 and the convex portion 52 are provided so that θ2 <θ is satisfied, where θ is an angle formed with the separation holder 41 when the head is in contact. Furthermore, the position where the convex portion 52 and the stopper 51 abut is set on the angle θ2 side with respect to the position where the separation holder 41 is mounted on the base portion 40. That is, when the angle formed by the surface of the base portion 40 and the separation holder 41 when the shaft 46 is positioned to be inserted into the bearing 44 is θ1, θ <θ1 is established. Therefore, the angle θ at which the above-described convex portion 52 hits the stopper 51 is set to θ2 <θ <θ1.

Separation unit 4 configured in this way, the position where the convex portion 52 hits the stopper 51 by setting as described above, the separation pressure to the separation roller 5 of the separation pad 42 is obtained, et al by the action of the pressure spring 43 . Further, when the separation pad 42 is replaced due to wear or the like, even if the separation roller 5 is separated from the separation holder 41, the protrusion 52 contacts the stopper 51 before reaching the position where the separation holder 41 comes off. The holder 41 is not rotated and blown by the action of the pressing spring 43. Even if the separation holder 41 is rotated by the action of the pressing spring 43 when the separation roller 5 is separated from the separation holder 41 by exchanging the separation pad 42, the stopper 51 hits the convex portion 52 and stops the rotation of the separation holder 41. The separation holder 41 is not skipped.

In the above embodiment, the rotation of the separation holder 41 is stopped by the protrusion 52 coming into contact with the stopper 51 of the separation holder 41. However, in the embodiment shown in FIG. 9, the protrusion 44a is provided on the inner peripheral surface of the bearing 44. This protrusion 44a is separation holder 41 rotates, its oval-shaped shaft 46 is restricted movement per its top, a portion other than the top portion is formed in a size that does not hit. In addition, although only one protrusion 44a functions sufficiently, in this example, two places are provided on the diagonal line in consideration of balance. Thus formed protrusion 44a is the top of the oval-shaped shaft 46 by a user applying a suitable strong force is overcome, the elastic force of the pressing spring 43 is set to a size insurmountable. By setting in this way, when the separation roller 5 is separated from the separation holder 41 by exchanging the separation pad 42, the top of the shaft 46 hits the protrusion 44a even if the separation holder 41 rotates by the action of the pressing spring 43. Since the rotation of the separation holder 41 is stopped, the separation holder 41 is not skipped during work.

FIG. 10 shows still another embodiment of the present invention . In this example, the friction piece 53 made of a rubber plate or the like is fixed to the connecting portion 46a of the shaft 46 , and the friction piece 53 is based on the position where the rotation of the separation holder 41 satisfies the angle θ shown in FIG. It is comprised so that rotation may be controlled in contact with the surface of the base part 40. FIG.

  If comprised in this way, even if it rotates with the force of the press spring 43, the friction piece 53 will contact | abut on the surface of the base part 40, and will be stopped. Then, the friction piece 53 is deformed and overcomes by applying a force stronger than the spring to the separation holder 41 at the time of attachment or removal. Therefore, the separation holder 41 can be attached and detached without any trouble.

FIG. 11 is a modification of the embodiment of FIG. 10, and in this example, the friction piece 54 is fixed not to the separation holder 41 side but to the surface of the base portion 40. Even when the separation holder 41 is rotated by the force of the pressing spring 43, as shown in FIG. 11B, the separation holder 41 hits the friction piece 54 at a position satisfying the angle θ described above, and the rotation is restricted. Is done. This friction Kosuhen 54 also separate holder 41 deformed by applying a force greater than the spring, it is possible to get over, can be easily carried out installation and removal of the separation holder 41 in the same manner as the above embodiment.

4 Separating Unit 5 Separating Roller 40 Base Part 41 Separating Holder 42 Separating Pad 43 Pressing Spring 44 Bearing 44a Protrusion 45 Notch 46 Shaft 51 Stopper 52 Protruding Part 53, 54 Friction Piece

JP 2000-219347 A Japanese Patent No. 3689629

Claims (7)

A feeding rotating body that rotates in the direction of feeding the sheet;
A separation holder that supports a friction member that forms a nip in contact with the feeding rotating body;
A holding frame on which the separation holder is rotatably and detachably mounted;
In the sheet feeding apparatus having an elastic member that presses the friction member in a direction to contact the feeding rotating body via the separation holder,
Restriction means for restricting rotation of the separation holder against the pressing force of the elastic member;
And a receiving portion for receiving one end of said elastic member,
The receiving part has a hollow part into which one end of the elastic member is guided,
The other end of the elastic member presses the separation holder outside the recess ,
The restricting means includes a convex portion formed on the separation holder, and a convex stopper provided on the holding frame body within the rotation trajectory of the convex portion and positioned outside the concave portion. A sheet feeding device characterized by the above.   The sheet feeding apparatus according to claim 1, wherein the separation holder is detachable when positioned at an angle with respect to the holding frame, and an angle from the surface of the holding frame at the time of detachment is θ1, Assuming that the angle from the surface of the holding frame when the friction member is in contact with the feeding rotating body is θ2, and θ is the angle from the surface of the holding frame when the restricting means is restricted, θ2 <θ <θ1 A sheet feeding device, characterized in that the sheet feeding device is set. 3. The sheet feeding apparatus according to claim 1 , wherein the convex portion gets over the convex stopper when the separation holder applies a force greater than or equal to an elastic force of the elastic member. Sheet feeding device. A sheet feeding apparatus according to any one of claims 1 to 3, the size of the recess portion, the sheet feeding, wherein substantially equal to the elastic member device. A sheet feeding apparatus according to any one of claims 1 to 4, wherein the contact with the one end of the elastic member, a sheet feeding apparatus is characterized by providing the inclined guide portion for guiding said recess. In sheet Oku置according to any one of claims 1 to 5, wherein the separation holder, integrally connected by a connecting portion, and is characterized by providing an insertable shaft portion to the holding frame sheet Feeding device. An image forming apparatus comprising: a sheet feeding apparatus according to any one of claims 1 to 6.

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