JP2001106412A - Paper discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper discharging device capable of providing excellent paper discharging performance and precisely keeping an outer diameter of a discharge auxiliary member to accelerate paper discharge performance. SOLUTION: This device is provided with a rotatably driven discharge roller, a driven roller abutting to the discharge roller, and the discharge auxiliary member coaxially rotatably provided in at least one of the discharge roller and the driven roller at a position axially shifted from an abutting position of the discharge roller and the driven roller. The discharge auxiliary member is formed in a circular shape as to a side surface so as to have slightly larger outer diameter than the discharge roller or the driven roller, and multiple recessed grooves engaging a rear end of the paper to stimulate to discharge the paper are provided around an outer periphery of the discharge auxiliary member.

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 used for an image forming apparatus such as an electrophotographic or electrostatic recording type printer or copier.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic or electrostatic recording type printer or copier, a sheet is fed and conveyed from a sheet cassette to a transfer position of a photosensitive drum. An image is formed by transferring and fixing the toner image formed on the photosensitive drum onto paper, and then discharging the toner image onto a discharge tray by a paper discharge device.

A paper discharge device for discharging the paper on which an image has been formed as described above onto a discharge tray includes a discharge roller that is driven to rotate, and a driven roller that abuts the discharge roller. The sheet is transported while being pinched by rollers, and the sheet on which an image is formed is discharged onto a discharge tray.

In such a paper discharge device, a discharge roll and a driven roller, or a flange 1 having a paper discharge performance provided on these rollers, in order to promote the paper discharge property.
In FIG. 00, a convex shape 101 as shown in the figure is provided, so that the rear end of the sheet is kicked by this convex shape 101 portion, and the rear end of the sheet is prevented from being left in the discharge port. I have.

[0005]

However, the prior art described above has the following problems. That is, in the case of the above-described conventional paper discharge device, in order to promote the paper discharge property of the paper, the discharge roll and the driven roller, or the flange portion 100 having the paper discharge performance provided on these rollers,
It is configured to have a convex shape 101 as shown in FIG. Therefore, when the paper comes into contact with the convex shape 101 of the flange portion 100, a mark of the convex shape 101 is attached to the paper, or the driven roller moves up and down with the passage of the convex shape 101 portion of the flange portion 100. However, there has been a problem that a stable transport posture of the paper cannot be obtained, and that an abnormal noise is generated due to a vertical movement of a driven roller or the like.

In particular, in the case of the above-mentioned conventional paper discharging device, if the convex portion 101 is provided on the flange portion 100, the outer diameter A of the flange portion 100 itself becomes a design value in order to improve the paper discharging performance. In addition, there is a demand for dimensional accuracy with a small error, and there is also an outer diameter dimension of A + 2 × B obtained by adding a value twice as large as the protrusion amount B of the convex shape 101 to the outer diameter dimension A,
By providing the convex portion 101 on the flange portion 100,
There has been a problem that a target dimension of the outer diameter dimension A, which is a design value, cannot be constantly obtained.

More specifically, since the outer diameter A of the flange 100 itself directly determines the sheet discharging performance, if the outer diameter A of the flange 100 varies, the paper can be stably formed. In order to prevent the paper from being ejected and to reduce the damage to the paper caused by the convex shape 101, it is desirable to set the height B of the convex shape 101 as small as possible. And A + 2
There is a problem that it is difficult to set both the outer diameter dimensions of the value of × B with high accuracy.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and the object of the present invention is to provide a good paper discharge performance as a matter of course. It is another object of the present invention to provide a paper discharge device capable of accurately maintaining the outer diameter of a discharge auxiliary member that promotes paper discharge performance.

[0009]

In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a discharge roll that is driven to rotate, a driven roller that contacts the discharge roll, and a driven roller that is driven by the discharge roll. A discharge auxiliary member provided coaxially and rotatably on at least one of the discharge roll and the driven roller at a position axially displaced from the contact position of the roller, wherein the discharge auxiliary member is provided coaxially The roller is formed in a circular shape having a slightly larger outer diameter than the discharge roll or driven roller to be driven, and a plurality of concave grooves are provided on the outer periphery thereof so as to engage with the rear end of the paper and promote the discharge of the paper. It is composed.

[0010]

According to the first aspect of the present invention, the discharge roll that is driven to rotate, the driven roller that comes into contact with the discharge roll, and the position that is axially shifted from the contact position between the discharge roll and the driven roller. A discharge auxiliary member provided coaxially and rotatably on at least one of the discharge roll and the driven roller, wherein the discharge auxiliary member has a slightly outer diameter than the discharge roller or the driven roller provided coaxially. It is formed in a large circular shape on the side, and the outer periphery thereof is provided with a plurality of concave grooves that engage with the rear end of the paper and promote the discharge of the paper. Can be surely obtained by the discharge roller and the driven roller which are in contact with each other. In addition, since the discharge auxiliary member having a slightly larger outer diameter than the discharge roll or the driven roller is provided at a position shifted in the axial direction from the contact position between the discharge roll and the driven roller, the discharge auxiliary member having a slightly larger outer diameter is used. By the member, the paper pinched by the discharge roll and the driven roller can be discharged in a state of being slightly wavy and bent,
Due to the rigidity of the paper itself bent in a wavy state, the paper can be discharged while being held in a substantially flat shape, and it is possible to reliably prevent the paper from interfering with the paper already discharged.

Further, according to the present invention, since a plurality of grooves are provided on the outer periphery of the discharge assisting member so as to engage with the rear end of the sheet to promote the discharge of the sheet, the disk-shaped flange is provided. As compared with the case where a plurality of convex shapes are provided on the outer periphery of the portion, the outer diameter of the discharge auxiliary member can be easily and accurately maintained.

Further, according to the present invention, since the plurality of grooves provided on the outer periphery of the discharge assisting member engage with the rear end of the sheet to promote the discharge of the sheet, the depth of the groove is reduced. The dimensional accuracy has almost no effect on the discharge performance of the sheet, and only the outer diameter of the discharge assisting member needs to be accurately maintained, so that the discharge assisting member can be easily manufactured.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 2 shows a laser printer as an image forming apparatus to which a paper discharge device according to Embodiment 1 of the present invention is applied.

In FIG. 2, reference numeral 1 denotes a laser printer main body. Inside the printer main body 1, an image processing section 2 for performing predetermined image processing on image information input from the outside, An image output unit 3 that outputs an image based on image information on which predetermined image processing has been performed by the image processing unit 2 is provided. The image processing unit 2 in the printer main body 1 reads image information sent from a host computer such as a personal computer (not shown), a communication line such as a telephone line or a LAN, or an image reading device (not shown). Image information or the like is input.

An ROS 4 (Rast 4) for performing image exposure based on image information subjected to predetermined image processing by the image processing unit 2 is provided to an image output unit 3 in the printer body 1.
ROS 4 is disposed, and in this ROS 4, a laser beam L is output in accordance with image information.
Image exposure by B is performed.

In the ROS 4, as shown in FIG. 2, a laser beam LB is emitted from a semiconductor laser (not shown) according to gradation data of image information. Laser light LB emitted from the semiconductor laser is deflected and scanned by a rotating polygon mirror (not shown), and is scanned on a photosensitive drum 5 as an electrostatic latent image carrier via a reflecting mirror (not shown).

As the photosensitive drum 5 on which the laser beam LB is scanned and exposed by the ROS 4, for example, a photosensitive member using an organic photoconductive substance (OPC) is used.
The photosensitive drum 5 is driven to rotate at a predetermined speed in a direction indicated by an arrow by a driving unit (not shown). The surface of the photosensitive drum 5 is previously charged to a predetermined potential by a charging roll 6 serving as a charging unit, and is then scanned and exposed to laser light LB in accordance with image information to form an electrostatic latent image. . The electrostatic latent image formed on the photosensitive drum 5 is developed by a developing roll 8 as a developer carrier of a developing device 7 to become a toner image.

The toner image formed on the photosensitive drum 5 is transferred onto a transfer sheet 10 as a transfer medium by a transfer roll 9 arranged so as to come into contact with the photosensitive drum 5, and the toner image The transfer paper 10 on which the image has been transferred is separated from the photosensitive drum 5. As shown in FIG. 2, the transfer paper 10 is fed from a paper feed cassette 12 of a paper feeder 11 disposed at a lower portion of the printer main body 1.
Sheets are fed one by one by a nudger roll 13, a feed roll 14, and a retard roll 15. The transfer paper 10 fed from the paper cassette 12 is transported by the transport roll 1
The photosensitive drum 5 is transported to a transfer position below the photosensitive drum 5 by the resist roll 6 and the resist roll 17.

As shown in FIG. 2, the printer body 1 is provided with a manual feed tray 18 on the left side surface. The manual feed tray 18 is rotated counterclockwise to a substantially horizontal position and stopped. By doing so, transfer media of different materials and sizes, such as OHP sheets and postcards, can be fed from the manual feed tray 18 via the feed roll 19 and the retard pad 20 having a large diameter.

The transfer paper 10 on which the toner image has been transferred from the photosensitive drum 5 is separated from the surface of the photosensitive drum 5 and then conveyed to the fixing device 21 as described above. The transfer paper 10 separated from the surface of the photoconductor drum 5 forms a toner image on the transfer paper 1 by heat and pressure by a heating roll 22 and a pressure roll 23 of a fixing device 21.
After the image is fixed on the upper side of the printer 1, the sheet is discharged onto the discharge tray 26 provided on the upper portion of the printer main body 1 by the discharge rollers 41, 42, and 43 of the discharge device 40 via the switching lever 24, and the image forming process is completed. .

Further, when an image is printed on both sides of the transfer sheet 10, as shown in FIG. 2, the transfer sheet 10 on which the image is printed on one side is not discharged onto the discharge tray 26 as it is. The transfer direction of the transfer paper 10 is switched by a switching lever 24 provided at the exit of the fixing device 21, and guided to a double-sided transfer path 29 provided with a plurality of transfer rolls 28 by a double-sided roll 27, so that the transfer paper 10 is turned upside down. Are transported to the transfer position of the photosensitive drum 5 again in a state where is inverted.

After the toner image transfer step is completed, the surface of the photosensitive drum 5 is cleaned of residual toner and paper dust by a cleaning device 31 having a cleaner blade 30, as shown in FIG. , For the next image forming step.

FIG. 3 is a front view of the paper discharge device used in the laser printer as viewed from the discharge tray 26, and FIG. 4 is a view of the paper discharge device used in the laser printer from the side opposite to the discharge tray 26. FIG. 5 is a side view of the paper ejection device used in the laser printer as viewed from the side.

By the way, in this embodiment, the discharge roller which is driven to rotate, the driven roller which comes into contact with the discharge roller, and the discharge roller which is displaced in the axial direction from the contact position between the discharge roller and the driven roller are placed. A discharge auxiliary member coaxially and rotatably provided on at least one of the roll and the driven roller, wherein the discharge auxiliary member has a side circular shape having a slightly larger outer diameter than the discharge roller or the driven roller provided coaxially. In addition, a plurality of grooves are provided on the outer periphery of the outer periphery thereof so as to engage with the rear end of the sheet and promote the discharge of the sheet.

That is, as shown in FIG. 1B, FIG. 3 and FIG. 4, the paper discharge device 40 according to this embodiment has three discharge rolls 41, 42, 43 which are driven to rotate, and Driven rollers 44 that abut against the rolls 41, 42, 43,
45 and 46 are provided. The above three discharge rolls 4
As shown in FIGS. 3 to 5, 1, 42 and 43 are provided on drive shafts 56, 57 and 58, which are driven to rotate a plurality of gears 48 to 55 by a drive motor 47.
It is configured to be driven to rotate by 58. As shown in FIG. 4, the first-stage discharge rolls 41 are provided with four first-stage discharge rolls 41 formed of a member such as rubber at predetermined intervals on the drive shaft 56. I have. The second-stage discharge roll 42 is provided with a drive shaft 57.
At a predetermined interval, two second-stage discharge rolls 42 formed of a member such as rubber are provided. Further, the final-stage discharge roll 43 is formed at a predetermined interval from the drive shaft 58 by a member such as rubber.
The final discharge rolls 43 are provided.

The drive shafts 56, 57, 58 are formed by bearing members 59 made of synthetic resin provided at both ends thereof.
The paper ejection device 40 is rotatably supported by frames 60 and 61.

The driven rollers 4, 42, 43 fixed to the drive shafts 56, 57, 58 have driven rollers 4.
4, 45 and 46 are in contact with each other.
The recording paper 10 is conveyed while being sandwiched by the rollers 1, 42, 43 and the driven rollers 44, 45, 46, and the recording paper 10 is discharged onto the discharge tray 26 by the final discharge rollers 43 and the driven rollers 46. It is configured as follows.

Further, the discharge rolls 41, 42, 43
4, a guide member 63 having a rib 62 for guiding the recording paper 10 is provided. As shown in FIGS. 1 and 3, a frame 64 constituting a side wall of the discharge tray 26 is provided vertically on the discharge tray 26 side of the paper discharge device 40.

Further, the driven roller 46 that comes into contact with the final-stage discharge roll 43 is divided into four corresponding to the four discharge rolls 43 as shown in FIGS. . As shown in FIG. 6, the driven rollers 46a located at both ends are formed by integrally connecting three disk portions 65, and the rotating shaft 66 of the driven rollers 46a A discharge auxiliary member 67 is coaxially and integrally provided at one end. The discharge auxiliary member 67 is formed in a disk shape, like the disk portion 65 of the driven roller 46a, but the radius of the discharge auxiliary member 67 is larger than the radius of the disk portion 65 of the driven roller 46a. It is set slightly larger (for example, about 1 mm). Further, on the outer periphery of the discharge assisting member 67, the recording paper 1
A plurality (six in the illustrated example) of recessed grooves 68 for urging the discharge of zero are provided.

Further, among the driven rollers 46 that come into contact with the final-stage discharge roll 43, the driven rollers 4 located inside
As shown in FIG. 7, the disk 6b is formed by integrally connecting five disk portions 69, and the rotating shaft 70 of the driven roller 46b is provided with a discharge assisting member at both ends in the axial direction. 71
Are provided coaxially and integrally. The discharge auxiliary member 71 is formed in a disk shape, like the disk portion 69 of the driven roller 46b, but the radius of the discharge auxiliary member 71 is
The radius is set to be slightly larger (for example, about 1 mm) than the radius of the disk portion 69 of the driven roller 46b. In addition, a plurality of the outer circumferences of the discharge assisting member 71 are engaged with the rear end of the recording paper 10 to urge the discharge of the recording paper 10 (in the illustrated example,
(Six) concave grooves 72.

In the above configuration, the paper discharging apparatus according to the present embodiment can not only obtain good paper discharging performance but also promote paper discharging performance in the following manner. It is possible to accurately maintain the outer diameter of the discharge auxiliary member.

That is, in the paper discharge device 40 according to this embodiment, as shown in FIGS. 1 and 3, the discharge roller 43 that is driven to rotate, the driven roller 46 that contacts the discharge roller 43, and the discharge roller Discharge auxiliary members 67 and 71 provided coaxially and rotatably with the driven roller 46 at positions axially displaced from the contact position between the roll 43 and the driven roller 46, and the discharge auxiliary members 67 and 71 A plurality of coaxially-formed driven rollers 46 whose outer diameter is slightly larger than the driven roller 46, and which has a plurality of outer circumferential surfaces that engage with the rear end of the recording paper 10 to promote the ejection of the recording paper 10. Are formed so that the concave grooves 68 and 72 are provided.
The conveyance force for discharging the paper is the discharge rolls 4 that abut against each other.
3 and the driven roller 46 can be reliably obtained.
In addition, since the discharge auxiliary members 67 and 71 having a slightly larger outer diameter than the discharge roller 43 or the driven roller 46 are provided at positions axially displaced from the contact position between the discharge roller 43 and the driven roller 46. As shown in FIG. 1A, the discharge roll 4 is moved by the discharge auxiliary member 17 having a slightly larger outer diameter.
The recording paper 10 nipped by the driven roller 3 and the driven roller 46 can be discharged in a state in which the recording paper 10 is slightly bent in a wavy state, and the recording paper 10 is substantially flattened by the rigidity of the recording paper 10 bent in a wavy state. The recording paper 10 can be discharged while being held in a state, and the contact with the already discharged recording paper 10 can be delayed, so that a stable recording paper storage state can be obtained.

Further, in this embodiment, a plurality of grooves 68, 72 are provided on the outer periphery of the discharge assisting members 67, 71 so as to engage with the rear end of the recording paper 10 and promote the discharge of the recording paper 10. Therefore, the outer diameters of the discharge assisting members 67 and 71 can be easily and accurately maintained as compared with a conventional case in which a plurality of convex shapes are provided on the outer periphery of a disk-shaped flange portion. be able to. The trailing edge of the recording sheet 10 is engaged with one of the plurality of concave grooves 68, 72 provided on the outer periphery of the ejection assisting members 67, 71, and the recording sheet 10 is kicked. Can be discharged in a correct position at a position distant from the camera.

Further, in this embodiment, a plurality of grooves 68, 72 provided on the outer periphery of the discharge assisting members 67, 71 are provided.
Is engaged with the rear end of the recording sheet 10 to promote the ejection of the recording sheet 10. Therefore, the dimensional accuracy of the depths of the grooves 68 and 72 hardly affects the ejection performance of the recording sheet 10. Instead, only the outer diameters of the discharge assisting members 67 and 71 need to be accurately maintained, and therefore, the discharge assisting members 67 and 71 can be easily manufactured.

[0036]

As described above, according to the present invention, it is possible to obtain not only good paper discharge performance, but also to reduce the outer diameter of the discharge auxiliary member for promoting the paper discharge performance. It is possible to provide a paper discharge device that can be maintained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a paper discharge device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a laser printer as an image forming apparatus to which the paper discharge device according to the first embodiment of the present invention is applied;

FIG. 3 is a front view of a paper discharge device used in the laser printer as viewed from a discharge tray side.

FIG. 4 is a rear view of the paper ejection device used in the laser printer as viewed from the side opposite to the ejection tray.

FIG. 5 is a side view of the sheet discharging device used in the laser printer as viewed from the side.

FIG. 6 is a configuration diagram showing a driven roller and a discharge assisting member.

FIG. 7 is a configuration diagram showing a driven roller and a discharge assisting member.

FIG. 8 is a configuration diagram showing a main part of a conventional discharging device.

[Explanation of symbols]

10: transfer paper, 40: paper feeder, 43: last stage discharge roll, 46a: driven roller, 46b: driven roller, 67
71: discharge auxiliary member, 68, 72: concave groove.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshinori Sasaki 3-7-1, Fuuchi, Iwatsuki-shi, Saitama Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Hideki Sato 3-7-1, Fuuchi, Iwatsuki-shi, Saitama No. Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Akihiro Oeda 3-7-1, Fuwa, Iwatsuki City, Saitama Prefecture Fuji Xerox Co., Ltd. Iwatsuki Office F term (reference) 3F049 AA01 CA02 CA05 DA11 DA12 LA02 LA05 LA07 LB03 3F053 HA07 HB02 LA02 LB03

Claims (1)

[Claims] A discharge roller that is driven to rotate, a driven roller that contacts the discharge roller, and at least a position of the discharge roller and the driven roller that is axially shifted from a contact position between the discharge roller and the driven roller. On the other hand, a discharge auxiliary member is provided coaxially and rotatably provided, and the discharge auxiliary member is formed in a side circular shape having a slightly larger outer diameter than a discharge roll or a driven roller provided coaxially, and
A paper discharge device, wherein a plurality of concave grooves are provided on the outer periphery thereof so as to engage with the rear end of the paper and promote the discharge of the paper.