JP2648518B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a sheet feeding device for feeding a sheet to an image processing section and a document placing section of an image forming apparatus.

<Problems to be Solved by the Related Art and the Invention> Generally, in the above-described paper feeding device, when the paper sent from a paper storage unit such as a cassette is transported to a predetermined position by a paper feeding roller, the paper feeding roller uses the paper feeding roller. By pressing a separation roller whose rotation is restricted on the conveyed sheet, two or more sheets are prevented from being conveyed simultaneously.

As shown in FIGS. 8 and 9, the rotation of the separation roller is controlled by a separation roller 90 provided opposite to the sheet feeding roller 93.
A ratchet wheel 91 is attached to one end portion 90a of the device so as to be integrally rotatable, and a locking member 92 is engaged with a claw 91a of the ratchet wheel 91 (see Japanese Patent Application Laid-Open No. 61-90943). The locking member 92 is formed of a leaf spring, and presses the separation roller 90 that is movable in the direction in which the separation roller 90 is pressed against the sheet feeding roller 93 and in the opposite direction to the sheet feeding roller 93 side, and rotates around the separation roller 90. Even if the surface is worn, the pressing force against the paper is not lost.

As described above, the rotation of the separation roller 90 is restricted by the one end 90a of the separation roller 90.
Is inclined with respect to the feed roller 93, and one end of the separation roller 90
The peripheral surface on the 90a side is pressed more strongly by the paper feed roller 93 than the peripheral surface on the other end 90b side. Therefore, there is a problem that the paper is transported obliquely, causing paper jam.

Further, in the above-mentioned paper feeding device, the pawl 91a of the ratchet wheel 91 is pushed when necessary, and the ratchet wheel 91 is rotated by the pawl pitch angle in the direction opposite to the rotation restricting direction by the locking member 92. Thus, the separation roller 90 is rotated by a predetermined angle, and the portion of the separation roller 90 pressed against the sheet is updated to a new portion. When the separation roller 90 is worn, the separation roller 90 is removed and replaced with a new one.

However, since the peripheral surface of the separation roller 90 to be replaced is used only intermittently at every claw pitch, the life of the separation roller 90 is short, and as shown in FIG. However, the unused portion 90d remains, which is disadvantageous in terms of cost.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a paper feeding device capable of suppressing skewed conveyance of a sheet and achieving a longer life of a separation roller.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a paper feed roller that conveys a sheet sent from a sheet storage unit to a predetermined position,
In a paper feeder having a pair of separation rollers that are pressed against the paper conveyed by the paper feed roller and prevent two or more papers from being simultaneously conveyed, the paper feed device is disposed between the pair of separation rollers. A ratchet wheel that rotates together with the pair of separation rollers by a claw pitch angle γ at times, and regulating means that engages with the pawls of the ratchet wheel when necessary to regulate the rotation of both separation rollers. Is detachably attached to the end of the ratchet wheel with the phases of the two rollers being different from each other by substantially half of the claw pitch angle γ.

<Operation> According to the above configuration, when the paper is conveyed by the paper feed roller, the regulating means regulates the rotation of the pair of separation rollers pressed against the paper, thereby feeding the two papers (multi-feed). ), The rotation of the separation roller is regulated by the above-described defining means by engaging a ratchet wheel claw interposed between the pair of separation rollers. in this way,
Since the rotation is regulated in the middle of both separation rollers, a reaction force to the paper supply roller side against the rotation regulation acts on the intermediate portion of both separation rollers, and the separation roller is inclined with respect to the paper supply roller. Never do. Therefore, during the conveyance of the paper, the pressing force of the two separation rollers against the paper becomes equal,
The oblique conveyance of the paper can be suppressed.

Further, when necessary, the separation roller is rotated by the claw pitch angle γ together with the ratchet wheel, so that the pressure contact portion of the separation roller against the paper is sequentially updated, so that the peripheral surface of the separation roller has the claw pitch angle γ. Used and worn out intermittently. By replacing the separation roller attached to one end of the ratchet wheel and intermittently worn as described above to the other end of the ratchet wheel, the phase of the separation roller is set to approximately the claw pitch angle γ. By shifting by half, the unused portion between the worn portions can be pressed against the sheet.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing a sheet feeding apparatus as one embodiment of the present invention, and FIG. 4 is a schematic view showing an end face of a ratchet wheel. With reference to FIGS. 1 and 4, the paper feeding device includes a paper storage unit 1 and a stopper unit 8 that contacts the front end of the paper stored in the paper storage unit 1 and regulates the conveyance of the paper. A paper feed roller 2 for transporting the paper sent from the paper storage unit 1 to a predetermined position, a pair of separation rollers 3 and 4 pressed against the paper transported by the paper supply roller 2, and the separation rollers 3; It has a ratchet wheel 5 interposed between the separation roller 4 and a regulating means 6 that engages with the pawl 51 of the ratchet wheel 5 to regulate the rotation of the ratchet wheel 5 when necessary.

The paper storage unit 1 operates in conjunction with the paper feed roller 2,
A feed roller 1a for feeding paper to the paper feed roller 2 is provided.

Each of the separation rollers 3 and 4 is provided to face the paper feed roller 2. The shaft 50 penetrating the separation rollers 3 and 4 and the ratchet wheel 5 is moved between the pair of side plates 11 and 12 so that the separation rollers 3 and 4 can move in the direction of pressing against the sheet feeding roller 2 and the direction of separating. It is freely supported. 20 is a separation roller
An urging means for urging both ends of the shaft 50 so that the rollers 3 and 4 are pressed against the paper feed roller 2.

The separation rollers 3 and 4 are, as shown in FIGS.
Fitting projections 3c, 4d are formed on the end faces 3a, 4b facing the end faces 5a, 5b of the ratchet wheel 5, respectively. These fitting projections 3c, 4d are detachably fitted in fitting grooves 5c, 5d formed in the end faces 5a, 5b of the ratchet wheel 5. Fitting grooves 5c, 5d
Are long grooves along the diameter lines α and β of the circular end faces 5a and 5b, respectively. As shown in FIG. 4, the diameter line α and the diameter line β are different in phase from each other by half γ / 2 of the pawl pitch angle γ of the ratchet wheel 5.

The regulating means 6 includes a solenoid 61 attached to the outer surface of the side plate 11, a lever 62 engaged with a control rod 61a of the solenoid 61, a shaft 63 supported between the pair of side plates 11, 12, and a center of the shaft 63. It is constituted by a claw member 64 fixed to the section.

As shown in FIG. 7, the restricting means 6 includes a solenoid.
The control rod 61a of the shaft 61 is advanced, and the shaft 63 is rotated counterclockwise in FIG. 7 via the lever 62, and the claw member 64 provided on the shaft 63 is engaged with the claw 51 of the ratchet wheel 5. The rotation of the separation rollers 3 and 4 is thereby restricted. In addition, the rotation of the separation rollers 3 and 4 by the restricting means 6 is controlled after a predetermined time elapses from the start of rotation of the sheet feeding roller 2 in conjunction with the advance roller 1a during sheet feeding. Will be Therefore,
During a predetermined time from the start of the paper feed roller 2, the separation rollers 3, 4 can be rotated by the above-described claw pitch angle γ by being driven by the paper feed roller 2, whereby the separation rollers 3, 4 can be rotated. The contact portion with the feed roller 2 is updated for each claw pitch angle γ.

Referring to FIGS. 5 and 6, the stopper means 8 includes a shaft 81 penetrating between the pair of side plates 11 and 12, and an operation position A provided at both ends of the shaft 81 for restricting the conveyance of a sheet. And a pair of stopper plates rotatable between a non-operating position B allowing the conveyance.
82, 83, a lever 84 fixed to the center of the shaft 81 and the side plate 12
The stop plates 82 and 83 are interposed between the paper storage unit 1
And a tension coil spring 85 that urges the shaft 81 via a lever 84 so as to advance into the inside.

A lever 86 is provided at the center of the shaft 81 of the stopper means 8.
Is fixed, and at the center of the shaft 63 of the restricting means 6, the stopper plates 82 and 83 are retracted from the operation position to the non-operation position by engaging with the lever 86 and resisting the tension coil spring 85. The lever 65 is fixed. Thereby, the regulating means 6
In conjunction with the regulation of the rotation of the separation rollers 3 and 4, the regulation of the sheet conveyance by the stopper means 8 can be released.

According to this embodiment, when the paper is conveyed by the paper feed roller 2, the regulating means 6 regulates the rotation of the pair of separation rollers 3, 4 pressed against the paper so that the paper 2
Although the sheet feed (double feed) is prevented, the rotation of the separation rollers 3 and 4 by the above-mentioned restricting means 6 is restricted by the pawl 51 of the ratchet wheel 5 interposed between the separation rollers 3 and 4 and the pawl member 64. Is performed by engaging. Thus, both separation rollers 3, 4
Is restricted in the middle of the rotation, the reaction force against this rotation regulation (the force to the paper feed roller 2 side) is
Acts in the middle of 4. Therefore, during the conveyance of the sheet, the separation rollers 3 and 4 do not incline with respect to the sheet feeding roller 2, and the pressing forces of the separation rollers 3 and 4 on the sheet become uniform, so that the oblique conveyance of the sheet can be suppressed.

When necessary, the separation rollers 3 and 4 are connected to the ratchet wheel 5.
When the roller is rotated by the claw pitch angle γ at the same time, the pressing portions of the separation rollers 3 and 4 against the paper are sequentially updated, so the peripheral surfaces of the separation rollers 3 and 4 are used intermittently for each claw pitch angle γ Being worn. The separation roller 3 having the intermittently worn portion is separated from the end 5a of the ratchet wheel 5 to the end.
5b, and set the phase of the separation roller 3 to the claw pitch angle γ.
The unused portion between the worn portions can be pressed against the sheet by shifting by half γ / 2. Similarly, by replacing the separation roller 4 from the end 5b to the end 5a of the ratchet 5, an unused portion of the separation roller 4 can be pressed against the sheet. Therefore,
The separation rollers 3 and 4 can be used over the entire circumference,
The service life of the separation rollers 3 and 4 can be extended.

The present invention is not limited to the above-described embodiment. For example, it is possible to externally engage the pawl 51 of the ratchet wheel 5 to rotate the separation rollers 3 and 4 by the pitch of the ratchet wheel. Various design changes can be made, such as providing fitting projections on the end faces and fitting grooves on the end faces of the separation rollers 3 and 4 without changing the gist of the present invention.

<Effects of the Invention> As described above, according to the present invention, the regulating means regulates the rotation of the separation roller by restricting the rotation of the ratchet wheel interposed between the separation rollers. The reaction force to the paper feed roller side against the regulation acts on the middle part of both separation rollers, and during the conveyance of the paper, the pressing force of both separation rollers against the paper becomes equal, and the oblique conveyance of the paper is suppressed. Can be. In addition, the separation roller attached to one end of the ratchet wheel, the peripheral surface of which is used intermittently at every claw pitch angle γ and is worn is replaced with the other end of the ratchet wheel to replace the separation roller. By shifting the phase of the roller by approximately half of the ratchet wheel claw pitch angle γ, the unused part between the worn parts can be pressed against the paper, so the entire circumference of the separation roller can be used and separated. This has a specific effect that the life of the roller can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a sheet feeding device as one embodiment of the present invention. FIG. 2 is an exploded perspective view of a separation roller and a ratchet wheel. FIG. 3 is a sectional view of the separation roller and a ratchet wheel. 5 to 7 are side views showing the operation of the paper feeder, FIG. 8 is a partial cross-sectional front view showing a conventional paper feeder, and FIG. FIG. 10 is a schematic view showing a separation roller, and FIG. 10 is a sectional view showing a worn state of a peripheral surface of the separation roller. 1 paper storage unit 2 paper feed roller 3 4 separation roller 5 ratchet wheel 6 regulating means 51 claw γ claw pitch angle

Claims (1)

(57) [Claims] A sheet feed roller for conveying a sheet sent from a sheet storage section to a predetermined position; and a sheet pressed by the sheet feed roller to prevent two or more sheets from being simultaneously conveyed. In a paper feeder having a pair of separation rollers, a ratchet wheel interposed between the pair of separation rollers and integrally rotating with the pair of separation rollers by a nail pitch angle γ when necessary, and a ratchet wheel when necessary. Restricting means for restricting the rotation of both separation rollers, and the pair of separation rollers are arranged such that the phases thereof are different from each other by substantially half of the claw pitch angle γ. A sheet feeding device, which is detachably attached to a section.