JP2011195322A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeder capable of stably feeding even paper of causing a curl and a flapping, with a simple constitution.SOLUTION: This paper feeder is mounted on a copier and a printer, and includes one paper feeding roller 31 and a separation roller 35 contacting with the paper feeding roller 31 under predetermined pressure. A roller 32 is arranged at a predetermined distance on both sides of the paper feeding roller 31 on the same axis with the paper feeding roller 31. A guide member 40 for constituting a paper feeding passage of the paper in a circular arc shape is oppositely arranged to the roller 32. The paper can be stably fed by regulating the paper by the roller 32 and the guide member 40.

Description

  The present invention relates to a paper feeding device, and more particularly, to a paper feeding device mounted on an image forming apparatus such as a copying machine or a printer based on electrophotography.

  Conventionally, this type of paper feeding device sandwiches a plurality of stacked paper sheets between a paper feeding roller and a separating roller, friction between the paper feeding roller and the paper, frictional force between the paper, and separating roller and paper. There is known a configuration in which only one sheet in contact with the sheet feeding roller is fed in the rotation direction of the sheet feeding roller by utilizing the difference in frictional force with the sheet feeding roller.

  If the paper to be fed is new, by restricting both sides of the paper, the posture of the paper can be controlled using the waist of the paper, and stable paper feeding is possible. When an image is formed on the second side of the paper on which the image is formed on the first side, the paper is heated once passing through the fixing unit, and thus curling and undulation are generated. If it is a high-end machine, it will be equipped with a dedicated re-feed mechanism for image formation on the second side in the machine, and even if the re-feed paper is curled, it will be bent appropriately and its side will be firmly Regulated and stable re-feeding is possible.

  On the other hand, in a low-priced machine that does not have the re-feeding mechanism, image formation on the second surface is performed using a manual feed mechanism. The conventional manual paper feed mechanism has a simplified configuration, and it is difficult to stably feed paper that has once passed through the fixing unit and has been curled or wavy.

  Patent Documents 1 and 2 can be cited as a paper feeding device provided with an auxiliary roller separately from the paper feeding roller. In Patent Document 1, conductive rollers are provided at some intervals on both sides of the paper feed roller to prevent double feeding and paper jam caused by the uppermost sheet electrostatically sticking to the next sheet. A sheet conveying apparatus as described above is described. Japanese Patent Application Laid-Open No. 2004-228561 describes a paper feed / conveying device in which a roller is provided so as to be movable in a direction orthogonal to the paper feed direction, and the position of the roller is corrected according to the amount of deflection of the paper.

JP 2008-81266 A JP-A-8-282865

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device that can feed paper stably even with curled or wavy paper with a simple configuration.

A sheet feeding device according to one aspect of the present invention is
One feed roller,
A separating roller that contacts the sheet feeding roller at a predetermined pressure;
A plurality of rollers arranged coaxially with the paper feed roller and at a predetermined distance on both sides of the paper feed roller;
A guide member that is disposed to face the roller and configures a paper feed path in an arc shape;
It is provided with.

  In the paper feeding device, the paper is fed one by one between the paper feeding roller and the separating roller based on the rotation of the paper feeding roller. At this time, even if the paper is curled or wavy, the guide member that is regulated by the plurality of rollers and the guide member and arranged opposite to the rollers forms the paper feed path in an arc shape. Therefore, the paper is smoothly and stably fed. In addition, stable feeding can be achieved with a simple configuration in which a roller and a guide member are provided.

  According to the present invention, it is possible to stably feed even a curled or wavy sheet with a simple configuration.

1 is a front view showing an external appearance of an image forming apparatus equipped with a paper feeding device according to an embodiment of the present invention. FIG. 3 is an elevation view of the sheet feeding device. It is a perspective view which shows the principal part of the said paper feeder. FIG. 4 is an elevational view showing a relationship between a roller and a guide member in the paper feeding device. FIG. 3 is a plan view showing a relationship between a paper feed roller, a roller, and a guide member in the paper feed device. FIG. 4 is an explanatory diagram illustrating a relationship between a sheet feeding roller and a separating roller in the sheet feeding device.

  Hereinafter, an embodiment of a paper feeding device according to the present invention will be described with reference to the accompanying drawings. In each figure, common parts and portions are denoted by the same reference numerals, and redundant description is omitted.

  First, an outline of an image forming apparatus equipped with a paper feeding apparatus according to an embodiment of the present invention will be described. As shown in FIG. 1, the image forming apparatus includes an apparatus main body 1 that holds an image forming mechanism based on electrophotography, and a scanner 10 that optically reads a document image. Although not shown, the image forming mechanism forms a toner image on a sheet by a known electrophotographic process with a photosensitive drum as a center. A door 2 and an operation panel 3 for accessing the mounted image forming mechanism are provided on the front side of the apparatus main body 1, and an automatic paper feed cassette 5 containing paper is installed at the lower part of the apparatus main body 1. ing. The toner image is transferred while the paper is conveyed upward on the right-hand side in FIG. 1, and is discharged / stacked one sheet at a time in the direction of arrow A on the discharge tray unit 7.

  A manual paper feed mechanism 20 is installed at the lower right side of the apparatus body 1. The manual sheet feeding mechanism 20 feeds a plurality of sheets placed on a flat tray 21 by a user one by one in order, and will be described in detail below.

  As shown in FIGS. 2 and 3, the manual paper feed mechanism 20 is coaxial with the paper feed roller 31, the separating roller 35 that contacts the paper feed roller 31 with a predetermined pressure, and the paper feed roller 31. The two rollers 32 (see FIG. 5) arranged at a predetermined distance on both sides of the paper feed roller 31 and the resin made of a resin that is arranged opposite to the rollers 32 and forms a paper feed path in an arc shape. Guide member 40 (see FIG. 4). The roller 32 is driven to rotate integrally with the paper feed roller 31 coaxially with the paper feed roller 31.

  The user stacks a desired number of sheets on a tray 21 opened substantially horizontally as shown in FIG. When the paper feed signal is turned on, the pickup plate 22 shown in FIG. 2 moves up with the shaft 22 a as a fulcrum, and presses the front end of the paper against the paper feed roller 31. As the paper feed roller 31 rotates in the direction of arrow a, the leading ends of a plurality of sheets enter between the paper feed roller 31 and the separating roller 35.

  Then, using the frictional force between the paper feeding roller 31 and the paper, the frictional force between the papers, and the frictional force between the separating roller 35 and the paper, only the uppermost sheet that contacts the paper feeding roller 31 is used. Is fed in the rotation direction of the paper feed roller 31. The separating roller 35 rotates following the rotation of the sheet feeding roller 31. The separation roller 35 is provided with a spring-type torque limiter 36 (see FIG. 6) coaxially. When a torque of a predetermined value or more acts on the separation roller 35 at the time of paper feeding, the separation roller 35 further follows. The rotation is prevented. A sheet feeding method based on such a difference in frictional force is conventionally known.

  In the present embodiment, as a specific configuration, two rollers 32 are arranged on both sides of the paper feed roller 31 at a predetermined distance, and the paper feed path of the paper is configured in an arc shape (see FIG. 3 and FIG. 4) are installed. When manually feeding paper using the paper feeding mechanism 20 to form an image on the second surface of paper on which an image has already been formed on the first surface, the paper has already passed through the fixing unit. It's curled or wavy. Since such a sheet is weak, it is difficult to restrict the side of the sheet and maintain the posture during sheet feeding. However, even such a sheet is regulated by the roller 32 and the guide member 40 at the time of feeding, and the guide member 40 disposed so as to face the roller 32 has an arcuate feeding path. Therefore, the paper is smoothly and stably fed.

  In order to ensure such sheet feeding stability, the manual feed mechanism 20 preferably adopts the following configuration.

  A resin film 41 (see FIG. 2) is disposed in the paper feed path from the separating roller 35 to the guide member 40. The resin film 41 is fixed to the frame 42 that holds the separation roller 35, passes through both sides of the separation roller 35, and reaches the guide member 40. The planar shape of the resin film 41 is as shown by a one-dot chain line in FIG. The guide member 40 has an opening 40 a formed around the paper feed roller 31 and the separating roller 35, and the paper feed is stabilized by covering the opening 40 a with the resin film 41.

  The roller 32 is preferably smaller in diameter than the paper feed roller 31, and the interval B (see FIG. 4) with the guide member 40 is preferably 1 to 10 mm. If the roller 32 has the same diameter as the paper feed roller 31, curling and undulation are excessively restricted. Further, when the interval B exceeds 10 mm, the regulation effect becomes weak. However, if the interval B is 0, the paper is jammed, and the interval B needs to be at least 1 mm. According to the experiments by the present inventors, the interval B was an appropriate value of 3.4 mm.

  Further, the roller 32 preferably has a distance D with respect to the paper feed center position C (see FIG. 5) of at least 50 mm. In the paper feed mechanism 20, the paper size to be fed is set to the maximum A4 horizontal feed (paper width 297 mm). When the distance D is increased, the paper is not suitable for small-size paper, and when it is reduced, the correction effect on the paper is weakened. In this embodiment, the interval D is set to 74.8 mm on the assumption that the minimum sheet size is A5 vertical feed (paper width 160 mm).

  Further, as shown in FIG. 6, the separation roller 35 is installed such that its own shaft core 35 a can be adjusted in parallel with the shaft core 31 a of the paper feed roller 31. Since the separation roller 35 has a torque limiter 36 on one side, the brake is applied by the torque limiter 36 during paper feeding. Even if the separation roller 35 is adjusted so that its shaft core 35a is strictly parallel to the shaft core 31a of the sheet feeding roller 31, the parallelism is shifted during sheet feeding. If so, it is possible to maintain the parallelism during actual paper feeding by predicting the parallelism deviation and adjusting the parallelism in advance.

(Other examples)
The paper feeding device according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist.

  For example, two rollers may be arranged on both sides of the paper feed roller. Further, the present invention can be applied not only to a manual sheet feeding mechanism but also to a normal automatic sheet feeding mechanism. Further, the shape and structure of the details of the paper feed roller, the separation roller, and the guide member are arbitrary.

  As described above, the present invention is useful for a paper feeding device mounted on a copying machine, a printer, or the like, and is particularly excellent in that stable paper feeding is possible with a simple configuration.

DESCRIPTION OF SYMBOLS 1 ... Apparatus main body 20 ... Manual feed mechanism 31 ... Paper feed roller 32 ... Roller 35 ... Separation roller 36 ... Torque limiter 40 ... Guide member 41 ... Resin film

Claims (5)

One feed roller,
A separating roller that contacts the sheet feeding roller at a predetermined pressure;
A plurality of rollers arranged coaxially with the paper feed roller and at a predetermined distance on both sides of the paper feed roller;
A guide member that is disposed to face the roller and configures a paper feed path in an arc shape;
A paper feeding device comprising:   The sheet feeding device according to claim 1, wherein the separating roller includes a torque limiter.   The sheet feeding device according to claim 1, wherein a resin film is disposed in a sheet feeding path from the separating roller to the guide member.   4. The roller according to claim 1, wherein the roller has a smaller diameter than the paper feed roller, and has an interval of 1 to 10 mm from the guide member. 5. Paper feeder.   The sheet feeding device according to any one of claims 1 to 4, wherein the roller is disposed at least 50 mm away from a sheet feeding center position.

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