JPH04338038A - Sheet feeder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to FRR (Feed&Rev) of paper feeding devices such as copying machines and laser printers.
The present invention relates to a paper feeding device of the type ``Erse Roller''.

0002

[Prior Art] As a conventional FRR type paper feeding device,
For example, there is one shown in FIG. In the paper feed device 1 shown in FIG. 3, when the paper feed cassette 2 is set in the cassette holder, the top surface of the recording paper 3 is raised to the proper position by a lever 2B that is linked to the lifting mechanism of the bottom plate 2A of the paper feed cassette 2.
controlled to maintain that position. The pickup roller 4 and the feed roller 5 are rotationally driven clockwise by the paper feed signal, and at the same time, the pickup arm 4A is rotated clockwise, and the pickup roller 4 is driven to rotate in the paper feed cassette 2.
It presses against the recording paper 3 inside with a predetermined pressure, picks up the recording paper 3, feeds it to the feed roller 5 side up to the nip, and leaves the paper surface. On the other hand, the reverse shaft 6A, which pivotally supports the separation roller 6 via the torque limiter 7, is driven to rotate clockwise. The recording paper 3 is fed into the nip between the feed roller 5 and the separation roller 6, and when two or more sheets of recording paper 3 are fed,
A torque limiter 7 attached to the separation roller 6 rotates the separation roller 6 clockwise to return it from the lower recording paper 3 to the paper feed cassette 2, and the recording paper is placed between the feed roller 5 and the separation roller 6. 3 does not exist or when one sheet of recording paper 3 is fed, the separation roller 6 is set to the torque limiter 7.
The recording paper 3 is rotated counterclockwise by the feed roller 5 against the torque of , and one sheet of recording paper 3 is reliably fed.

0003

However, in such a conventional paper feeding device, a torque limiter 7 for controlling the pickup roller 4 to press against the recording paper 3 at a predetermined pressure, a recording paper There is a problem in that a complicated mechanism is required, such as a height detection sensor for keeping the height of the recording paper 3 constant, a solenoid for raising the recording paper 3, and a paper lifting device such as a sector gear.

0004

[Object of the Invention] The present invention has been made against the background of such conventional technology, and by eliminating the vertical movement of the pickup roller and fixing it, it is possible to determine the height of the recording paper by hitting it against the pickup roller. This eliminates the need for a complicated mechanism to determine the height of the recording paper, and by using a feed gear with a one-way clutch, the rotation of the feed roller is interrupted from being transmitted to the pickup roller, and the rotation of the feed shaft is started. To provide a paper feeding device that can sometimes create a paper feeding interval by causing a pickup roller to start rotating.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention collects the recording paper picked up by the pickup roller that contacts the recording paper in the paper feed cassette into only one sheet between the feed roller and the separation roller. In a paper feeding device that feeds paper separately, the pickup roller is rotatably supported on a roller shaft at a constant height above the paper feeding side end of the paper feeding cassette so as to be in contact with the recording paper. When the feed shaft is driven, the feed roller is connected to a feed gear with a one-way clutch attached to the feed gear, and when the feed shaft is driven, the feed roller is driven in the paper feeding direction according to the rotation of the feed gear. The rotation of the feed roller is driven by the feed shaft, and when the feed shaft is not driven, the transmission of the rotation of the feed roller to the pickup roller is interrupted by a feed gear with a one-way clutch.

[0006]

[Operation] In the present invention, since the pickup roller is fixed to a roller shaft of a constant height, the height of the recording paper is determined by abutting against the pickup roller. In addition, when the feed shaft is not driven, the rotation of the feed roller is cut off from being transmitted to the pickup roller by the feed gear with a one-way clutch, and the transmission is not transmitted to the pickup roller. ,
The pickup roller is not driven.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1 and 2 are diagrams showing an embodiment of a paper feeding device according to the present invention. First, the configuration will be explained. 1 and 2, reference numeral 11 denotes a paper feeder, and the paper feeder 11 is used to store recording paper 13 on the paper feed cassette 12 above the paper feed side end of the paper feed cassette 12 of a copying machine (not shown). A roller shaft 14 provided at a constant height parallel to the paper surface and orthogonal to the paper feeding direction; a pickup roller 15 rotatably supported by the roller shaft 14 and in contact with the recording paper 13 in the paper feeding cassette 12; have. A pickup gear 15A is integrally provided at one end of the pickup roller 15. The recording paper 13 in the paper feed cassette 12 is placed on the bottom plate 16 inside the paper feed cassette 12, and is urged upward by a spring 17 so that the uppermost recording paper 13 comes into contact with the pickup roller 15.

A feed shaft 21 connected to a feed drive source 20 is provided downstream of the paper feed of the pickup roller 15, and the feed shaft 21 is driven by the feed drive source 20 in synchronization with the timing of feeding the recording paper 13. Ru. The feed shaft 21 pivotally supports a feed gear 22 with a one-way clutch 22A, and also supports a feed roller 23. The feed drive source 20 drives the pickup roller 1 through an idler gear 24 and a pickup gear 15A that mesh with the feed gear 22 with a one-way clutch during driving.
5 counterclockwise and the feed roller 23
is driven counterclockwise. When the feed drive source 20 is not driven, the rotation of the feed roller 23 is not transmitted to the feed gear 22 due to the operation of the one-way clutch 22A, so the transmission to the pickup roller 15 is cut off, and the pickup roller 15 is not driven.

Separation rollers 25 are provided below the feed rollers 23 in correspondence with the feed rollers 23.
5 is supported by the separation roller shaft 26 via a torque limiter, and when an external force larger than the torque of the torque limiter is applied to the separation roller 25, the separation roller 25 is driven, and even if a torque smaller than the torque of the torque limiter is applied, separation is not performed. The rollers 25 are not driven, that is, the separating rollers 25 are stopped.

A registration roller 28 connected to a drive source (not shown) is provided downstream of the feed roller 23, and a registration pressure roller 29 is provided below the registration roller 28 for applying pressure to the registration roller 28 side. It is being The registration rollers 28 are driven in synchronization with the rotation of a photosensitive drum (not shown) of the copying machine. When the registration rollers 28 are driven, the drive source for the feed shaft 21 is configured to stop driving.

Next, the paper feeding operation of the recording paper 13 of the paper feeding device 11 will be explained with reference to FIGS. 2(a) to 2(d). Figure 2 (a
), when the feed drive source 20 is turned on and the feed shaft 21 is driven, the feed gear 22 with one-way clutch starts rotating, and the pickup roller 15 and feed roller 23 connected to the feed gear 22 with one-way clutch start rotating. Followed, pickup roller 15
picks up the recording paper 13 and feeds it to the feed roller 23 side.

In FIG. 2(b), when two or more sheets of recording paper 13 are fed between the feed roller 23 and the separation roller 25, the torque of the torque limiter of the separation roller 25 overcomes the frictional force between the sheets. The separation roller 25 stops rotating, the recording paper 13 in contact with the separation roller 25 stops together with the separation roller 25, and the topmost recording paper 13 in contact with the feed roller 23 stops.
is fed to the registration roller 28 side by the counterclockwise rotation of the feed roller 23, and the registration roller 28
28 and waits just in front of the registration roller 28.

In FIG. 2(c), the registration roller 28
starts driving in synchronization with the rotation of the photosensitive drum of the copying machine, and at the same time, the driving of the feed shaft 21 stops. When the registration rollers 28 start driving, the recording paper 13 is sent toward the photosensitive drum by the registration rollers 28 and the resist pressure rollers 29, and as the recording paper 13 moves, the feed rollers 23 and the pickup rollers 15 rotate together. The rotation of the feed roller 23 is not transmitted to the one-way clutch-equipped feed gear 22 by the one-way clutch 22A, and therefore the pickup roller 15 is not driven, but is rotated by the movement of the recording paper 13.

In FIG. 2(d), the registration roller 28
The recording paper 13 is sent to the photosensitive drum side by the drive of
When the rear end 13a of the recording paper 13 passes through the pickup roller 15, the feed roller 23 rotates with the movement of the recording paper 13, but the rotation of the feed roller 23 is controlled by the feed gear 22 with one-way clutch by the one-way clutch 22A.
That is, since no power is transmitted to the pickup roller 15, the pickup roller 15 does not rotate until the feed shaft 21 starts to be driven. Therefore, the recording paper 13 is not picked up, and a gap is created between it and the preceding recording paper 13.

Next, the operation will be explained. A pickup roller 15 is rotatably supported on a fixed roller shaft 14 above the leading end of the paper feed cassette 12 in contact with the recording paper 13, so that the recording paper 13 can be removed from the recording paper 13 simply by abutting against the pickup roller 15. The height of the recording paper 13 is determined, and there is no need for a complicated mechanism for determining the height of the recording paper 13 as in conventional paper feeding devices.

When the feed shaft 21 is not driven, the accompanying rotation of the feed roller 23 is not transmitted to the one-way clutch equipped feed gear 22 by the one-way clutch 22A, and therefore is not transmitted to the pickup roller 15. Therefore, when the rear end 13a of the recording paper 13 passes through the pickup roller 15, the pickup roller 15 does not rotate until the feed shaft 21 starts to be driven. Therefore, the recording paper 13
is not picked up, and a gap is created between it and the preceding recording paper 13.

[0017]

[Effects of the Invention] As explained above, according to the present invention,
By eliminating the vertical movement of the pickup roller and fixing it, the height can be determined by hitting the recording paper against the pickup roller, eliminating the need for a complicated mechanism to determine the height of the recording paper.In addition, it is equipped with a one-way clutch. By using the feed gear, transmission of the rotation of the feed roller to the pickup roller is interrupted, and the pickup roller starts rotating when the feed shaft starts rotating, thereby making it possible to create a paper feeding interval.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a paper feeding device according to the present invention, in which (a) is an overall explanatory view, and (b) is a sectional view of a main part thereof.

2 is a diagram showing various states in FIG. 1, (a) is when the recording paper is picked up, (b) is when it is separated, (c) is when the registration roller is driven, and (d) is the rear end of the recording paper. FIG. 3 is an explanatory diagram showing the operation of each when the roller passes through the pickup roller.

FIG. 3 is a diagram showing a conventional paper feeding device, in which (a) is an explanatory front view thereof, and (b) is a sectional view of a main part thereof.

[Explanation of symbols]

11 Paper feeding device 12 Paper feeding cassette 13 Recording paper 14 Roller shaft 15 Pickup roller 21 Feed shaft 22 Feed gear with one-way clutch 23
Feed roller 25 Separation roller

Claims (1)

[Claims] 1. A paper feeding device that separates and feeds a recording paper picked up by a pickup roller that contacts the recording paper in a paper feed cassette into only one sheet between a feed roller and a separation roller, wherein the pickup roller is rotatably supported on a roller shaft at a constant height above the paper feed side end of the paper feed cassette so as to be in contact with the recording paper, and is connected to a feed gear with a one-way clutch attached to the feed shaft. When the feed shaft is driven, the feed roller is driven in the paper feeding direction according to the rotation of the feed gear, and the feed roller pivotally supported on the feed shaft is driven in the paper feeding direction according to the drive of the feed shaft,
A paper feeding device characterized in that when the feed shaft is not driven, transmission of rotation of the feed roller to the pickup roller is interrupted by a feed gear with a one-way clutch.