JPH07144774A - Paper feeder - Google Patents

Abstract

PURPOSE:To provide a paper feeder for an image forming device by which a trace of a paper feeding roller is not left on a paper sheet at paper feed stopping time by bringing the paper feeding roller into pressure contact with the paper sheet in a paper feeding cassette for paper feeding operation time only. CONSTITUTION:A paper feeder is composed of a plate body 22a rotatable by being supported with a rotary shaft 21, a paper feeding roller body 24b pivoted to the plate body 22a, a first driving member 21a to rotate together with the rotary shaft 21 and a second driving member 23a arranged between the first driving member 21a and the roller body 24b, and rotates through the second driving member 23a when it comes into contact with the roller body 24b and a feeding paper sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for feeding a sheet stored in a sheet feeding cassette of an image forming apparatus such as a copying machine, a printing machine, a printer or a facsimile to a printing unit.

[0002]

2. Description of the Related Art In a conventional sheet feeding device, a sheet feeding roller is always pressed against a sheet when a sheet feeding cassette is mounted.

[0003]

However, if the paper and the roller are always in contact with each other when the paper feeding cassette is mounted as in the conventional paper feeding device, the rubber component of the roller is transferred to the paper. In addition, there are drawbacks such as the fact that a trace is left on the paper due to the contact pressure of the roller.

The present invention has been made in view of the above-mentioned circumstances, and provides a sheet feeding device in which a sheet feeding roller is brought into pressure contact with a sheet in a sheet feeding cassette only during a sheet feeding operation.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a rotatable plate member supported by a rotary shaft, a paper feed roller member pivotally supported by the plate member, and a first rotary member that rotates together with the rotary shaft. Drive member and a second drive member provided between the first drive member and the roller body, and the roller body causes the second drive member to move when abutting against paper for feeding. It is characterized by rotating through.

[0006]

When the rotating shaft is rotated in the same direction as the roller body when the roller body is not in contact with the paper, the second drive member does not rotate and the plate body rotates. When the plate body rotates and the roller body comes into contact with the paper in due course, the second drive member rotates at this time to rotate the roller body and perform paper feeding.

When the rotary shaft is rotated in the reverse direction, the plate member swings upward, so that the roller member is separated from the paper.

[0008]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the paper 11 is stored in the paper feed cassette 12 from above, and when the paper feed cassette 12 is pushed into the image forming apparatus 10, the paper holding plate 15 is raised obliquely to form a cylindrical shape. The paper feed roller 24b is at a position where the paper 11 can be fed. At this time, the paper feed roller 24b is separated from the paper 11 by a predetermined distance as shown in FIG. In the figure, reference numeral 13 is a corner claw provided to prevent double feeding of sheets.

In the figure, reference numeral 21 is a rotary shaft, and 22a, 22.
Reference numeral b denotes a pair of roller holding plates, which are roller holding plates 22a and 22a.
A rotation shaft 21 is attached to the base end of b, and the rotation shaft 21 is rotated by a motor (not shown) so as to rotate a predetermined number of rotations in the rotation direction of the paper feed roller 24b and a predetermined angle in the opposite direction. It has become. The roller holding plates 22a and 22b have the rotation shaft 21.
It is adapted to rotate up and down by a predetermined angle around.
Therefore, a stopper (not shown) is provided so that when the roller holding plates 22a and 22b move up, the paper feeding roller 11 stops at a predetermined distance from the paper.

Reference numeral 21a is a drive gear, which is fixedly attached to the rotary shaft 21 and rotates together with the rotation of the rotary shaft 21. The drive gear 21a has a pendulum gear 23.
a is meshed, the pendulum gear 23a is loosely fitted to a fixed shaft 23 fixed to the roller holding plate 22a, and a coil spring which is an elastic member is provided between the pendulum gear 23a and the roller holding plate 22a. 23b is attached in a compressed state.

A feed gear 24a meshes with the pendulum gear 23a, and a rubber feed roller 24 is provided coaxially with the feed shaft 24 to which the feed gear 24a is attached.
b is attached, and when the feeding gear 24a rotates, the paper feeding roller 24b also rotates.

Next, the operation of the paper feeding device of the present invention will be described.
FIG. 3 shows a state before sheet feeding, and from this state, the rotation shaft 21 and the drive gear 21a are moved by the arrow a by a motor (not shown).
When rotated in the direction, the pendulum gear 23a meshed with this
Does not rotate due to frictional resistance with the coil spring 23b, and the roller holding plates 22a and 22b rotate around the rotating shaft 21 in the direction of the arrow b, and as shown in FIG.
When b b oscillates until it comes into pressure contact with the paper 11, and when it comes into pressure contact with the paper 11, the pendulum gear 23a overcomes the frictional resistance with the coil spring 23b (FIG. 2) and rotates in the direction of arrow c, so that the feeding gear 24a also simultaneously. It rotates in the direction of arrow d.
Therefore, the paper is sent to the printing unit 14 by the rotating paper feed roller 24b.

To stop the feeding of the paper 11, the motor (not shown) is rotated in the reverse direction, or the rotary shaft 21 is rotated in the reverse direction through the reverse device (not shown) while keeping the rotation direction of the motor unchanged. The plates 22a and 22b rotate upward, come into contact with a stopper (not shown) and stop, and a predetermined space is held between the paper 11 and the paper feed roller 24b. In this embodiment, the paper feed roller is rotated by the combination of gears. However, the drive gear and the pendulum gear may be composed of two rollers, and the rollers may be pressed against the paper feed roller.

[0014]

According to the present invention described in detail above, the following effects are exhibited. That is, since the paper and the paper feed roller come into contact with each other only during the paper feed operation, the rubber component of the paper feed roller does not transfer to the paper and no trace is left on the paper due to the pressure of the paper feed roller.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a perspective view of a sheet feeding device according to an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing the operation of the paper feeding device according to the embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing the operation of the sheet feeding device according to the embodiment of the present invention.

[Explanation of symbols]

 21 rotary shaft 21a drive gear (first drive member) 22a, 22b roller holding plate (plate) 23 fixed shaft 23a pendulum gear (second drive member) 23b coil spring 24 feeding shaft 24a feeding gear 24b feeding Paper roller (roller body)

Claims (1)

[Claims] 1. A rotatable plate member supported by a rotary shaft, a sheet feeding roller member axially supported by the plate member, a first drive member which rotates together with the rotary shaft, and a first drive member. And a second drive member provided between the roller body and the roller body, and the roller body rotates via the second drive member when abutting against the paper for feeding. Paper feeding device.