JP2002087607A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device capable of suppressing curling of a paper end part and having stable paper feeding performance in spite of its simplified structure not requiring any separate member such as an auxiliary roller, in the case of a paper feeding device having a feed tray, a feed roller integrally formed of resin, bearing parts for holding the feed roller, and a separation means. SOLUTION: This paper feeding device can suppress the curling of a paper end part without any separate member such as an auxiliary roller by making the outer diameter D2 of a shaft part 1b of the feed roller 1 slightly smaller than the outer diameter D1 of a rubber part 1a, and has stable performance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder of an image forming apparatus having a paper feed tray inserted into the image forming apparatus in a direction perpendicular to a paper conveying direction.

[0002]

2. Description of the Related Art Conventionally, in a paper feeder of a copying machine or the like, a paper feed tray inserted into an image forming apparatus in a direction perpendicular to a paper conveying direction and a pad separation using a friction pad for paper separation are often used. ing. In this case, there are a configuration in which paper feed rollers are provided on the image forming apparatus side and a configuration in which paper feed rollers are provided on the paper feed tray. When a paper feed roller is provided on the image forming apparatus side, when the paper tray is pulled out, if the paper is present between the paper feed roller and the separation unit, the pressure of the separation unit is prevented to prevent the transfer paper from being damaged. It was necessary to cancel, and the configuration of the device was complicated. In addition, when a paper feed roller is provided on the paper feed tray, the shaft portion is made of metal due to a problem in strength. Here, since the metal shaft is expensive, the diameter of the metal shaft is made as small as possible, and the difference from the diameter of the paper feed roller becomes large, so that the curl at the end of the paper cannot be suppressed.

In view of this, a method of providing an auxiliary roller on the shaft of a sheet feeding roller has been considered, as represented by the method disclosed in Japanese Utility Model Publication No. 4-0335310 and Japanese Patent Publication No. 2518309.
Further, a method has been considered in which the half-moon feeding roller and the shaft are integrated with resin as in the method disclosed in Japanese Patent Application Laid-Open No. 9-052633.

[0004]

However, actual fairness 4-0
In the methods disclosed in Japanese Patent No. 35310 and Japanese Patent No. 2518309, there is a problem that the auxiliary roller has a different configuration, the configuration becomes complicated and the cost increases. Also, Japanese Patent Laid-Open No. 9-
In the method disclosed in Japanese Patent No. 052633, since the use range of the paper feed roller is only partially on the circumference, it is not suitable when the use range of the paper feed roller is the entire circumference such as pad separation. Further, in the non-paper feed state, the cutout portion of the paper feed roller needs to face the paper side, so that a separate curl pressing means is required.

SUMMARY OF THE INVENTION In view of the above problems, the present invention relates to a paper feeder having a paper feed tray, a paper feed roller integrally formed of resin, a bearing for holding the paper feed roller, and a separating means. Although it is a simplified configuration that does not require a separate member, it can suppress the curl at the edge of the paper,
An object of the present invention is to provide a sheet feeding device having a performance capable of stably feeding a sheet.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to claim 1 comprises a paper feed tray,
In a sheet feeding device having a sheet feeding roller in which a holder portion holding a high friction material and a shaft portion are integrally formed of resin, a bearing portion holding the sheet feeding roller, and a separating device, the diameter of the shaft portion of the sheet feeding roller Is slightly smaller than the outer diameter of the high friction material.

According to a second aspect of the present invention, there is provided a paper feed tray,
In a sheet feeding device having a sheet feeding roller in which a holder portion holding a high friction material and a shaft portion are integrally formed of resin, a bearing portion holding the sheet feeding roller, and a separating device, the diameter of the shaft portion of the sheet feeding roller Is slightly smaller than the inner diameter of the high friction material.

According to a third aspect of the present invention, in the paper feeder according to the first or second aspect, the shape of the shaft between the bearings of the paper feed rollers is symmetrical about the conveyance center.

[0009] The invention described in claim 4 is based on claims 1, 2,
3. The sheet feeding device according to item 3, wherein the cross section of the shaft portion of the sheet feeding roller is formed by a radial portion from the axis and a circular portion.

With the above construction, in a paper feeder having a paper feed tray, a paper feed roller integrally formed with a resin, a bearing for holding the paper feed roller, and a separating means, another member such as an auxiliary roller is used. It is possible to suppress the curl at the end of the paper without any need, and to provide a paper feeder with stable performance.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described below in detail with reference to the drawings. (First Embodiment) A basic structure of a sheet feeding device according to a first embodiment will be described with reference to FIGS. The paper feed tray 8 is guided by rails 5 and 6 provided in an image forming apparatus (not shown) and inserted into the image forming apparatus (not shown). In the paper feed tray 8, a bottom plate 9 for placing and rotating the paper, a pressure spring 4 for pressing the bottom plate 9, and a separation pad 2a contacting the paper feed roller 1 and separating the paper one by one are provided. Is provided.
The separation pad 2a is held by a pad base 2b and is pressed by a separation spring 3. Feed roller 1 is rubber part 1
a and a shaft portion 1b, and is held via a bearing portion 8a of the paper feed tray 8.

Here, the operation of the transfer paper from the paper feed tray 8 will be described. The paper placed on the bottom plate 9 in the paper feed tray 8 is pressed by the pressure spring 4 almost simultaneously with the insertion of the paper feed tray 8 into the image forming apparatus main body (not shown).
At the same time. On the other hand, separation pad 2
a is also brought into contact with the feed roller 1 by the separation spring 3. Then, the sheet is conveyed along the guide plate 10 to the image forming unit (not shown) on the downstream side by the sheet feed roller 1 to which the drive is transmitted from the driving device (not shown).

Next, the features of the first embodiment will be described with reference to FIGS. The outer diameter D2 of the shaft portion 1b of the feed roller 1 is slightly smaller than the rubber outer diameter D1 of the rubber portion 1a. The relationship between the rubber outer diameter D1 of the rubber portion 1a and the outer diameter D2 of the shaft portion 1b is determined by the difference A between the amount of deflection of the rubber portion 1a and the shaft portion 1b due to the pressing force applied to the sheet feeding roller 1, and the amount of deformation of the rubber portion 1a. B (represented by R1-R1 'shown in FIG. 4)
D1-D2> 2 × (A + B) is set, and the shaft 1
The contact between the sheet b and the sheet is prevented from lowering the sheet conveyance force. According to the above configuration, the curl at the end of the sheet abutting on the rubber portion 1a can be suppressed by the shaft portion 1b, so that another member such as an auxiliary roller is not required.

(Second Embodiment) The features of the second embodiment will be described with reference to FIG. Here, the operation of the sheet feeding device is the same as that of the first embodiment, and the description is omitted. The outer diameter D2 of the shaft portion 1b of the paper feed roller 1 in the second embodiment is slightly smaller than the rubber inner diameter d1 of the rubber portion 1a. For this reason, although the curl pressing amount of the paper is smaller than that of the paper feed roller 1 in the first embodiment, the rubber portion 1a can be inserted from the end as it is, and the assembling property is improved and the rubber portion 1a can be prevented from being deformed. .

(Third Embodiment) The features of the third embodiment will be described with reference to FIG. The left and right lengths L1 and L2 of the shaft portion 1b of the sheet feed roller 1 are the same, and the outer diameter D2 is also the same. For this reason, the deflection of the paper feed roller 1 can be made equal to the conveyance center, so that the pressing force received by the rubber portion 1a of the paper feed roller 1 is distributed symmetrically, so that the oblique feeding of the paper called skew can be prevented. .

(Fourth Embodiment) The features of the fourth embodiment will be described with reference to FIG. The cross section of the shaft portion 1b of the paper feed roller 1 is formed alternately of a radial portion from the axis and a circular portion. For this reason, it is possible to suppress the variation in the deflection when the sheet feeding roller 1 rotates, and to perform stable sheet feeding.

[0018]

According to the first aspect of the present invention, the paper feed tray inserted into the image forming apparatus in a direction perpendicular to the paper conveying direction, the holder for holding the high friction material, and the shaft are integrally formed of resin. In a paper feeder having a paper feed roller, a bearing for holding the paper feed roller, and a separating unit, the diameter of the shaft of the paper feed roller is made slightly smaller than the outer diameter of the high friction material, so that Even if there is no separate member such as a roller, the curl at the end of the sheet can be suppressed by the sheet feeding roller, and a sheet feeding device with a simple configuration and low cost can be provided.

According to the second aspect of the present invention, a paper feed tray inserted into the image forming apparatus in a direction perpendicular to the paper conveying direction, a holder holding a high friction material, and a shaft are integrally formed of resin. In a paper feeder having a paper roller, a bearing for holding the paper feed roller, and a separating unit, the diameter of the shaft of the paper feed roller is slightly smaller than the inner diameter of the high friction material, so that the auxiliary roller The curl at the end of the sheet can be suppressed by the sheet feeding roller without the separate member, and the assembling property of the rubber portion is improved.

According to the third aspect of the present invention, since the shape of the shaft between the bearings of the paper feed roller is symmetrical about the center of conveyance,
Skew due to uneven bending of the paper feed roller can be prevented, and a paper feed device with stable performance can be provided.

According to the fourth aspect of the present invention, since the cross section of the shaft portion of the feed roller is formed by the radial portion from the axis and the circular portion, the variation in deflection when the feed roller rotates is reduced. It is possible to provide a paper feeder that can be held down and has stable performance.

[Brief description of the drawings]

FIG. 1 is a layout diagram showing a first embodiment.

FIG. 2 is a perspective view showing the first embodiment.

FIG. 3 is a layout view showing a main part of the first embodiment.

FIG. 4 is a layout diagram showing a state of a main part of the first embodiment.

FIG. 5 is a layout view showing a main part of the second embodiment.

FIG. 6 is a layout view showing a main part of a third embodiment.

FIG. 7 is a layout view showing a main part of a fourth embodiment.

[Explanation of symbols]

 1 	 Feed roller 1a 	 Rubber part 1b 	 Shaft part 2a 	 Separation pad 2b 	 Pad base 3 	 Separation spring 4 	 Pressure spring 5, 6 	 Rail 8 	 Paper feed tray 8a 	 Bearing 9 	 Bottom plate 10 	 Guide plate

Claims (4)

[Claims] 1. A paper feed tray inserted into an image forming apparatus in a direction perpendicular to a paper conveyance direction, a holder provided in the paper feed tray and holding a high friction material, and a shaft are integrally formed of resin. In a paper feeding device having a paper feeding roller, a bearing for holding the paper feeding roller, and a separating unit that separates sheets provided in the paper feeding tray one by one, a diameter of a shaft portion of the paper feeding roller is provided. Characterized by a slightly smaller outer diameter of the high friction material. 2. A paper feed tray inserted into an image forming apparatus in a direction perpendicular to a paper conveying direction, a holder provided in the paper feed tray and holding a high friction material, and a shaft are integrally formed of resin. In a paper feeding device having a paper feeding roller, a bearing for holding the paper feeding roller, and a separating unit that separates sheets provided in the paper feeding tray one by one, a diameter of a shaft portion of the paper feeding roller is provided. Characterized in that the diameter is slightly smaller than the inner diameter of the high friction material. 3. The sheet feeding device according to claim 1, wherein a shape of a shaft portion between bearing portions of the sheet feeding roller is symmetric with respect to a conveyance center. 4. The paper feeding device according to claim 1, wherein a cross section of a shaft portion of the paper feeding roller is formed by a radial portion from an axis and a circular portion. Paper feeder.