JPH03279125A - Sheet transfer device - Google Patents

Abstract

PURPOSE:To provide an inexpensive sheet transfer device by combining a one- way clutch with a lead screw which rotates in one-way direction and reciprocates, so that both drive of a pick belt and shift of a sheet guide can be made by a single motor. CONSTITUTION:During normal rotation of a motor 11, a drive shaft 12 and a pick belt 13 are rotated through the intermediary of a timing belt 13 so as to transfer a sheet. Simultaneously, gears 15, 16 are rotated, but no torque is transmitted to a lead screw 18 which rotates in one-way direction and reciprocates, since a one-way clutch is press-fitted in the gear 16 with a predetermined direction. Accordingly, a sheet guide 10 is not shifted. When the sheet size is changed, the motor 11 is reversed so that a torque is transmitted to the lead screw 18 by means of the one-way clutch which is in a coupling direction, and accordingly, the sheet guide 10 is shifted to a position corresponding to the sheet size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a paper conveying device in a printing device, a copying device, etc.

[Background of the invention]

The prior art will be explained by taking as an example a switchback reversing device for a cut paper laser beam printer capable of double-sided printing.

The toner on the photosensitive drum 4 is transferred to the surface of the paper 2 picked from the paper hopper 1 at a transfer station 3. Then, the paper 2 passes through the fixing station 5 and is once stacked on the stacker 6 of the switchback station. In the case of double-sided printing, when the paper is reversed and the pick belt 13 sends the paper to the transfer station 3 again, double-sided printing is performed and the paper is discharged to the stacker 6.

In the stacker 6 of the switchback station,
The sheets fed into the tray 8 by the rollers 7 bounce when they come into contact with the backstop 9, causing variations in the stack position in the width direction. This not only causes jams, but also causes variations in paper feeding positions and printing devices. Therefore, in order to regulate the stack position, a movable paper guide 10 and a fixed paper guide 21 are provided in a direction perpendicular to the paper feeding direction to suppress variations in stack position accuracy. The moving paper guide 10 is
Since it is necessary to move the paper depending on the size of the paper, the stacker 6 of the switchback station has conventionally been provided with one motor for moving the paper guide and one motor for driving the pick belt. This has the disadvantage that the device is large and expensive.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide an inexpensive paper conveying device. We focused on the fact that if used, the paper guide could be moved back and forth just by rotating the motor in a fixed direction.
The pick belt, motor, lead screw, and paper are rotated so that the lead screw for moving the paper guide rotates only when the motor is rotated in the reverse direction using a one-way clutch, and only the pick belt rotates when the motor is rotating in the forward direction and the paper is being transported. The relationship between the guides has been devised.

[Embodiments of the invention]

FIG. 1 shows a specific embodiment of the present invention.

When conveying paper, the motor 11 rotates normally and the timing belt 14
, the pick belt 13 is also rotated at the same time as the vertical movement shaft 12 is rotated. Then, the gear 16 rotates at the same time as the gear 15 rotates. A one-way clutch is press-fitted into the gear 16, but the operating direction of the one-way clutch is determined so that the lead screw 18 does not rotate in this direction of rotation. Therefore, during paper conveyance, the paper guide 10 does not move but remains at an appropriate position.

When the paper size changes, the motor 11 is reversed,
A gear 16 is rotated via a timing belt 14, a pick pulley 12, and a gear 15.

At this time, the one-way clutch is set in the connecting direction, and the lead screw 18 rotates. On the other hand, the lead screw 18 has a groove for reciprocating rotation in one direction, so the holder 19 fitted to the lead screw 18 reciprocates, and the paper guide 10 moves to an appropriate position according to the paper size.

〔Effect of the invention〕

According to the present invention, when adjusting the paper guide according to the size of the paper, a single motor can move the paper guide and drive the pick belt, so a simple and inexpensive paper conveying device can be used. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a paper feeding device according to the present invention, and FIG. 2 is a schematic diagram showing a feeding system of a laser beam printer. FIG. 3 is a schematic diagram of the lead screw 18. In the figure, 1 is a paper hopper, 2 is paper, 3 is a transfer station, 4 is a photosensitive drum, 5 is a fixing station, and 6
is a stacker, 7 is a roller, 8 is a tray, 9 is a backstop, 10 is a paper guide, 11 is a motor, 12 is a pick pulley, 13 is a pick belt, 14 is a timing belt, 15 is a gear 16 is a gear, 17 is a one-way clutch ,
18 is a lead screw, 19 is a guide holder, and 20 is a stacker.

Claims (1)

[Claims] 1. A paper transport means having a drive shaft, a drive motor that drives the drive shaft, a fixed paper guide that guides one end of the paper when the paper is transported, and a fixed paper guide that is perpendicular to the paper transport direction depending on the paper width. In a paper transport device having a movable paper guide that moves in a direction and guides the other end of the paper, a one-way rotation reciprocating lead screw is screwed into the paper guide member, and the lead screw is connected via a one-way clutch. , is connected to the drive shaft of the paper conveyance means, and interrupts torque transmission when the drive shaft drives the paper conveyance means in the paper feeding direction, and when the drive shaft rotates in the reverse direction, the one-way clutch operates in the direction of operation of the one-way clutch. A paper conveyance device characterized in that the paper conveyance device is configured to connect a lead screw and a lead screw.