JPH07206195A - Paper feed device of image forming device - Google Patents

Abstract

PURPOSE:To prevent any non-feed of a paper sheet generated in a separation means in a paper feed device of an image forming device provided with a rotating roller and a separation blade as the paper sheet separation means on a paper sheet carrying passage. CONSTITUTION:A taper part 20 is formed on the part contacting with a rotating roller 15 of a separation blade 16. The taper part 20 is positioned on the tangential line of the rotating roller 15, and further the friction coefficient of the taper part 20 is made large.

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 of an image forming apparatus such as a copying machine, a printer and a facsimile, and more specifically, a sheet separating device including a rotating roller and a separating blade that abuts against the rotating roller. The present invention relates to a sheet feeding device provided with means.

[0002]

2. Description of the Related Art A paper feeder of the above-mentioned type is disclosed in Japanese Patent Laid-Open No.
This is well known from Japanese Patent Publication No. 31747 and will be described with reference to FIG.

In FIG. 3, a stack of paper sheets 2 on a paper feed tray 1
Are fed one by one from the uppermost one by the paper feed roller 3, pass through the sheet separating means including the rotating roller 5 and the separating blade 6 provided in the conveying path 4, and the registration roller pair 7, and then the photosensitive drum 8 of the photosensitive drum 8. It is sent to the transfer unit 9.

When the uppermost paper and the lower paper are superposed and simultaneously fed out by the paper feed roller 3, the lower paper progresses slowly due to contact friction with the separating blade 6, and only the upper paper precedes. Then, it abuts on the peripheral surface of the rotating roller 5, and is fed to the transfer portion 9 through a small gap between the rotating roller 5 and the separation blade 6 by the rotation of the rotating roller 5. The delayed lower sheet cannot withstand the frictional force of the separating blade 6, and the small gap is blocked by the preceding sheet. Double feed is prevented.

[0005]

However, in the sheet feeding device of the above-described type, as shown in FIG. 4, the edge 6a of the separating blade 6 bites into the peripheral surface of the rotating roller 5 and, as a result, the sheet to be conveyed is There is a problem that it becomes difficult to enter the gap (nip) between the rotating roller and the separation blade, resulting in no feed.

Further, in the sheet separating means composed of a rotating roller and a separating blade, the leading edge of a plurality of sheets of paper which has arrived is stepwise determined by the angle of the separating blade with respect to the peripheral surface of the rotating roller, so that the sheet to be conveyed is In the edge separation method that separates only into sheets, the number of sheets that can be separated is limited. When the number of sheets exceeding the separating ability reaches the separating blade at one time, only one sheet cannot be separated, and a large number of sheets are fed (double feeding).

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to provide a sheet feeding device of the above-mentioned type, which does not cause non-feeding, and prevent the above-mentioned double feeding.

[0008]

According to the present invention, the above-mentioned problems can be solved by forming a taper on a portion of the separating blade which abuts on a rotating roller.

In order to solve the above problems, the present invention proposes that the tapered portion of the separating blade is on the tangent line of the rotating roller at the contact position of the separating blade.

In order to solve the above problems, the present invention proposes that the coefficient of friction of the tapered portion of the separating blade is made larger than the coefficient of friction of other surfaces of the separating blade.

Further, according to the present invention, in order to increase the friction coefficient of the tapered portion, the tapered portion of the separating blade is roughened so that the other surface of the separating blade is not roughened or is left as a ground surface. Propose to be.

[0012]

Since the taper is provided at the portion of the separating blade that comes into contact with the rotating roller, the edge of the separating blade does not bite into the peripheral surface of the rotating roller, and the non-feed of the paper due to this biting is eliminated.

Further, since the taper portion is configured to be on the tangent line of the rotating roller at the contact position of the separating blade, and the friction coefficient of the taper portion is increased, the taper portion has a friction separating effect. It became effective to prevent double feeding of paper.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the taper portion 20 is provided in the region of the edge 16a of the separating blade 16 which abuts against the rotating roller 15.
Is formed, which increases the angle at the edge 16a of the separating blade 16 and
It is reduced or eliminated that 6a bites into the peripheral surface of the rotating roller 15.

In FIG. 2, the tapered portion 20 'formed on the edge 16a of the separating blade 16 is the edge 1a.
Rotating roller 1 at the contact point between 6a and the peripheral surface of the rotating roller 15
It is located on the tangent line T of 5. As a result, the tapered portion 20 'has a friction separating effect.

Further, the separating blade 16 shown in FIG.
It is also possible to configure the coefficient of friction of the tapered portion 20 ′ to be larger than the coefficient of friction of the other surface of the separating blade 16. This allows the tapered portion 20 'to have a more effective friction separating effect.

In order to increase the coefficient of friction of the tapered portion 20 ', the tapered portion 20' is roughened so that the tapered portion 20 'has a greater coefficient of friction than the other surfaces of the separating blade 16. be able to.
In this case, the surfaces of the separating blade other than the tapered portion 20 'are not roughened or left as the ground surface.

[0019]

EFFECTS OF THE INVENTION By forming a taper at the portion of the separating blade that abuts on the rotating roller, the non-feeding of the sheet separating means composed of the rotating roller and the separating blade is eliminated.

By providing the taper portion with a friction separating function, it is possible to effectively exhibit the double feeding preventing function of the paper separating means.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a separation blade according to the present invention.

FIG. 2 is an explanatory view of another embodiment of the separating blade according to the present invention.

FIG. 3 is an explanatory diagram of a sheet feeding device provided with a rotating roller and a separating blade.

FIG. 4 is an explanatory view showing the biting of the edge of the separation blade.

[Explanation of symbols]

 15 Rotating Rollers 16 Separation Blade 16a Separation Blade Edge 20, 20 'Tapered Part

Claims (4)

[Claims] 1. In a sheet feeding device of an image forming apparatus provided with a sheet separating means composed of a rotating roller and a separating blade abutting against the rotating roller, a taper is formed at a portion of the separating blade abutting the rotating roller. A paper feeding device characterized by the above. 2. The sheet feeding device according to claim 1, wherein the taper portion of the separating blade is on a tangent line of the rotating roller at the contact position of the separating blade. 3. The sheet feeding device according to claim 1, wherein a friction coefficient of the tapered portion of the separating blade is set to be larger than a friction coefficient of the other surface of the separating blade. 4. The paper feed according to claim 3, wherein the tapered portion of the separating blade is roughened and the other surface of the separating blade is not roughened or remains a ground surface. apparatus.