JPH11208957A - Paper discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small sized paper discharging device that can prevent the rear end of recording paper from remaining and prevent a paper jam with smooth driving. SOLUTION: A paper discharging device is provider with a driving roller 11A and a paper discharge roller 13A rotated in contact with the driving roller 11A, and recording paper 8 is discharged being inserted between the contact faces of the driving roller 11A and paper discharge roller 13A. The outer peripheral part of the paper discharge roller 13A is provided with a cutout part 15A with a contact face 17 formed to face forward in a rotating direction so as to make the rear end of the recording paper 8 come in contact with it at the time of delivering the recording paper 8 and with a guide face 19 formed being extended forward in the rotating direction from the contact face 17. A groove of approximately V-shaped cross section is formed at the guide face 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper discharge device applied to, for example, an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a printer, a copying machine, a facsimile or the like is provided with a paper discharging device for discharging the recording paper after image recording to the outside. The paper discharging device includes a driving roller and a paper discharging roller that rotates in contact with the driving roller, and rotates the driving roller so that the recording paper is discharged by the rotating driving roller and the discharging roller. Has become. Japanese Patent Application Laid-Open No. 4-66 discloses such a paper discharging device.
As shown in FIG. 5, a convex protrusion 43 is formed on the outer peripheral portion of the paper discharge roller 41, and the rear end of the recording paper 45 to be discharged is fixed to the protrusion 43 as shown in FIG. In some cases, the trailing end of the recording paper 45 is not left on the paper discharge roller 41 to prevent the recording paper 45 that is subsequently discharged later from being hindered.

[0003]

However, the discharge roller 41 having the projection 43 formed on the outer periphery as described above.
Is brought into direct contact with the drive roller, and when the protrusion 43 comes into contact with the drive roller, the contact state between the two is different between when the protrusion 43 comes into contact with the other arc portion. There is an inconvenience that the movement is not performed smoothly, causing blurring periodically, and causing problems such as vibration and abnormal noise.

In this case, as shown in FIG. 6, in order to smoothly rotate the discharge roller 41, another roller 4 having no protrusion is provided.
4 is provided on the same rotation shaft 45 as the paper discharge roller 41, and it is necessary to apply a rotational motion to the paper discharge roller 41 from the drive roller 47 through this. There is a disadvantage that the space must be increased.

Japanese Utility Model Laid-Open Publication No. 64-56446 discloses a lower discharge roller 49 as schematically shown in FIG.
A contact surface 51 extending in the radial direction of the roller and facing forward in the rotational direction and a plane 52 extending forward from the plane and facing outward of the roller have a V-shaped groove (notch) on the peripheral surface of the roller. )
Is disclosed. However, according to the technique disclosed in this publication, if the trailing end of the recording paper 45 to be ejected has a curl or warp, the trailing end of the recording paper 45 contacts the contact surface 51.
7, there is a disadvantage that the recording paper 45 is greatly warped and causes a jam as indicated by a one-dot chain line in FIG.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a small-sized sheet discharging device which can prevent the trailing end of a recording sheet from remaining, can drive smoothly, and can prevent a jam.

[0007]

According to one aspect of the present invention, there is provided an image forming apparatus comprising: a driving roller; and a discharge roller which rotates in contact with the driving roller. And a discharge surface that is inserted into the contact surface of the discharge roller and discharges the recording paper, when the recording paper is sent out to the outer peripheral portion of the discharge roller, the contact surface facing the front in the rotation direction and the rear end of the recording paper abutting. A notch formed with a guide surface extending forward from the contact surface in the rotational direction, wherein a groove having a substantially V-shaped cross section is formed in the guide surface. is there.

According to the first aspect of the present invention, the rear end of the recording paper abuts against the abutting surface of the notch of the paper discharge roller which rotates together with the driving roller, and the recording paper is extruded.
As a result, the trailing end of the recording paper does not remain on the paper discharge rollers, and it is possible to prevent the progress of the recording paper continuously discharged later from being hindered. In addition, since the paper discharge roller is provided with a rotational motion by contacting the drive roller at an outer peripheral portion (hereinafter, referred to as an arc portion) other than the notch portion, the paper discharge roller is smoothly rotated and periodically shakes, The occurrence of problems such as vibration and abnormal noise is suppressed. Furthermore, the guide surface has a cross section of approximately V
When the trailing edge of the recording paper is curled or warped (hereinafter simply referred to as “curl”
In this case, the rear end abuts against the wall of the V-shaped groove, and a force in the paper discharging direction can be applied to the recording paper. To prevent

Furthermore, the paper discharge roller is configured to directly contact the drive roller, and the paper discharge roller in contact with the drive roller is formed with a notch, so that a separate rear end feed roller is not provided. In addition, the size of the device can be reduced.

According to a second aspect of the present invention, in the first aspect, the contact surface is continuous with a wall surface forming a substantially V-shaped cross section of the groove. .

According to the second aspect of the present invention, since the wall surface of the substantially V-shaped groove formed in the guide surface and the contact surface are continuous, the rear end of the recording paper is curled. In case,
The rear end of the recording paper can be easily guided from the contact surface to the wall surface of the groove having the V-shaped cross section, and the recording paper can easily contact the wall surface of the groove.

According to a third aspect of the present invention, in accordance with the first or second aspect of the present invention, there are provided a plurality of drive rollers and a plurality of paper discharge rollers corresponding to the drive rollers, and a cut formed on the paper discharge roller. The positions of the notches are different from each other.

According to the third aspect of the present invention, when the notch portion of one of the discharge rollers comes to a position where it contacts the drive roller, the arc portion of the other discharge roller contacts the drive roller. I do. Therefore, the rotation of the drive roller is always transmitted to the paper discharge roller, and the occurrence of vibration, abnormal noise, and the like is further reduced.

According to a fourth aspect of the present invention, in the third aspect of the present invention, each of the paper discharge rollers has only one notch, and each notch has a circular shape. At the target position.

According to the fourth aspect of the present invention, since only one cutout portion is provided for each discharge roller, it is possible to minimize vibration, abnormal noise, and the like caused by the cutout portion. it can. In addition, since each notch formed in each paper discharge roller is located at a target position on the circumference of the paper discharge roller, it is possible to prevent uneven driving of each paper discharge roller and to drive the paper discharge roller smoothly. it can.

[0016]

Embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a schematic view showing a sheet discharging device provided in the image forming apparatus. The paper discharging device 2 provided on the upper surface of the image forming apparatus 1 has the transport unit 3 at a position corresponding to the paper discharging unit 7 of the image forming apparatus 1. The transport section 3 includes a drive roller 3a and a transport roller 3b. Transport unit 3
Downstream of the guide plate, two guide plates 4a and 4b are arranged, and a transport path is formed between the two. Guide plates 4a, 4b
The paper discharge unit 5 is provided on the downstream side of. A tray 6 for receiving the recording paper 8 discharged from the paper discharge unit 5 is provided downstream of the paper discharge unit 5.

As shown in FIG. 4, the paper discharge section 5 includes a pair of drive rollers 11A and 11B and each of the drive rollers 11A and 11B.
1B includes a pair of paper discharge rollers 13A and 13B. The drive shaft 21 has two drive rollers 11A, 1
1B, and these drive rollers 11
The two paper discharge rollers 13A and 13B are attached to the rotating shaft 23 so as to rotate in contact with A and 11B, respectively. The discharge rollers 13A and 13B are mounted so that the rotation shaft 23 is coaxial, and the notch 15B of the other discharge roller 15B rotates 180 ° with respect to the notch 15A of the one discharge roller 13A. It is fixed in the position that was set. Therefore, the cutouts 15A and 15B formed on the paper discharge rollers 13A and 13B are located at alternate positions.
As a result, when one of the discharge rollers 13A rotates and the notch 15A comes to a position in contact with one of the drive rollers 11A, the other discharge roller 13B is moved to the arc portion 13a.
(See FIGS. 2 and 3) and is in contact with the other drive roller 11B. Conversely, when the notch 15B of the other discharge roller 13B comes to a position in contact with the other drive roller 11B, the one discharge roller 13A comes into contact with the one drive roller 11A at the arc portion 13a. I have. In this way, the paper discharge rollers 13A, 13B are connected to the cutouts 15A,
Although the contact rollers 15A and 13B are not in contact with each other but alternately contact the drive rollers 11A and 11B at the arc portions 13a, the rotational movement can be always applied to the discharge rollers 13A and 13B, and the occurrence of vibration and abnormal noise can be reduced. it can.

Here, the configuration of the cutouts 15A and 15B formed in each of the paper discharge rollers 13A and 13B will be described. Since the configuration of each of the cutouts 15A and 15B is substantially the same, Only the notch 15A formed in the paper discharge roller 13A will be described.

As shown in FIGS. 2 and 3, the notch 1
5A, a contact surface 17 facing the front in the rotational direction when the recording paper 8 is sent out to the outer peripheral portion of the paper discharge roller 13A, and a rear end of the recording paper contacting the contact surface 17; An extending guide surface 19 is formed.

The guide surface 19 is formed with a groove 22 having a substantially V-shaped cross section. When the trailing end of the recording paper 8 is curled toward the discharge roller 13A, the groove 22 receives the trailing end and abuts against the wall surface 22A of the groove 22. Wall 2
2A is continuous with the contact surface 17 and facilitates guiding the rear end of the recording paper 8 from the contact surface 17 to the wall surface 22A of the groove 22 having a V-shaped cross section. As a result, the curled recording paper 8
Of the groove 22 can easily contact the wall surface 22A of the groove 22.

In the paper discharging device 2 having the above configuration, paper is discharged as follows. First, a recording paper 8 as an output medium such as a plain paper or an overhead projector (OHP) sheet is output from a paper output unit 7 of the image forming apparatus 1.
Is inserted into the transport unit 3. The recording paper 8 is carried out by the driving roller 3a and the conveying roller 3b, and is guided by the guide plates 4a, 4b.
The sheet is sent to the sheet discharging section 5 along the line b.

In the discharge section 5, the recording paper 8 is inserted into the contact surface 21 of the rotating drive roller 11A (11B) and the discharge roller 13A (13B) as shown in FIG. Paper. When the discharge of the recording paper 8 proceeds, the rear end of the recording paper 8 enters from the guide surface 19 of the notch 15 and strikes against the contact surface 17.
The recording paper 8 is pushed out in the paper discharge direction by the rotation of the paper discharge roller 13, and the paper discharge is completed.

As described above, according to the paper discharging device 2, the notch 15 allows the rear end of the recording paper 8 to be reliably pushed out, and the paper can be discharged without fail. Also, the paper discharge roller 1
In No. 3, since the arc portion 13a comes into contact with the drive roller 11, the paper discharge roller 13 is given a rotational motion. Therefore,
Unlike a conventional paper discharge roller having a protrusion formed on the outer peripheral portion, it is possible to suppress the occurrence of periodic blurring and problems such as vibration and abnormal noise. Further, it is not necessary to provide another roller for transmitting the rotational motion, the number of parts can be reduced, the cost can be reduced, and the paper discharge device 2 can be downsized.
Mounting space can be reduced.

On the other hand, as shown in FIG. 3, when the trailing edge of the recording paper 8 is curled, the trailing edge is
A can be applied to the recording paper by applying a force in the paper discharge direction
Even in such a case, the recording paper 8 can be reliably pushed out,
It is possible to prevent the curl portion, which has conventionally occurred, from expanding toward the drive roller 11A, thereby preventing a jam caused by such a curl expansion.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, one notch 15A, 15B is formed on each of the paper discharge rollers 13A, 13B, but a plurality of notches may be provided.

In the embodiment shown in FIG. 3, the notch 15B of the other discharge roller 15B is fixed at a position rotated by 180 ° with respect to the notch 15A of the one discharge roller 13A. However, the angle is not particularly limited to 180 °, and the notches 15A and 15B may be located at different positions.

Further, the wall surface of the groove 22 is not limited to a straight section, but may be a curved section or an arc section.

[0029]

As described above, according to the first aspect of the present invention, the trailing edge of the recording sheet does not remain on the sheet ejection roller, and the recording sheet continuously ejected later advances. Not only can it be prevented from being hindered, but also the contact between the drive roller and the paper discharge roller can be made smooth, and it is possible to suppress the occurrence of periodic blurring, vibration, abnormal noise, and other problems. further,
Since it is not necessary to provide a separate roller, the number of parts can be reduced, cost can be reduced, and the size of the apparatus can be reduced. Further, since the V-shaped groove is formed on the guide surface, the recording paper can be reliably discharged even when the rear end of the recording paper is curled.

According to the second aspect of the present invention, since the wall surface of the substantially V-shaped groove formed on the guide surface is continuous with the contact surface, the rear end of the recording paper is curled. In addition, the rear end of the recording paper can easily contact the wall surface of the groove.

According to the third aspect of the invention, the rotation of the drive roller is always transmitted to the paper discharge roller, and the occurrence of vibration and abnormal noise can be further reduced.

According to the fourth aspect of the present invention, since only one cutout portion is provided for each discharge roller, vibrations, abnormal noise, and the like caused by uneven contact between the discharge roller and the drive roller are provided. Can be minimized and can be driven smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a paper discharge device provided in an image forming apparatus.

FIG. 2 is a side view showing a driving roller and a paper discharge roller of the paper discharge device shown in FIG.

FIG. 3 is a side view of a drive roller and a paper discharge roller showing a paper discharge state when the recording paper is curled.

FIG. 4 is a perspective view showing a driving state of a driving roller and a discharge roller.

FIG. 5 is a side view showing a driving roller and a paper discharge roller of a conventional paper discharge device.

FIG. 6 is a perspective view showing a roller unit of a conventional sheet discharging device.

FIG. 7 is a side view of a conventional paper discharge roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper discharge device 3 Conveyance part 5 Paper discharge part 8 Recording paper 11A, 11B Driving roller 13A, 13B Paper discharge roller 15A, 15B Notch part 17 Contact surface 19 Guide surface 22 Groove 22A Wall surface of groove

Claims (4)

[Claims] 1. A paper discharge device, comprising: a drive roller; and a paper discharge roller that rotates in contact with the drive roller, and discharges recording paper by inserting the recording paper into a contact surface between the drive roller and the paper discharge roller. A guide surface that faces forward in the rotational direction when the recording paper is sent out to the outer peripheral portion of the paper discharge roller, and a rear end of the recording paper abuts on; and a guide extending from the contact surface along the rotational front. And a notch formed with a surface, and the guide surface has a substantially V
A sheet discharging device characterized in that a groove having a cross section is formed. 2. The device according to claim 1, wherein the contact surface is continuous with a wall surface forming a substantially V-shaped cross section of the groove.
2. The paper ejection device according to claim 1. 3. The apparatus according to claim 2, wherein the drive roller and a plurality of paper discharge rollers corresponding to the drive roller are coaxially provided, and the positions of cutouts formed in each paper discharge roller are different from each other. The sheet discharging device according to claim 1. 4. The apparatus according to claim 3, wherein each of the discharge rollers has only one cutout, and each cutout is located at a target position on the circumference. Paper ejection device.