KR20040048501A - Apparatus for driving pick-up of printer - Google Patents

Abstract

PURPOSE: A pick-up driving device of an image forming apparatus is provided to prevent a cam of a pick-up gear and a driving gear from interfering each other. CONSTITUTION: A pick-up driving device(20) of an image forming apparatus includes a driving gear(6), a pick-up gear(21) engaged with the driving gear, a cam(22) fixed to the pick-up gear, and a stopper(23) protruded from the outer face of the cam. The driving gear is rotated by a driving motor to transmit a driving force to a pick-up roller. The pick-up gear receives the driving force from the driving gear and is mounted on a pick-up shaft(3). The cam is integrated with the pick-up gear. The stopper has a sloped face(23a) such that the pick-up gear is finely moved in the axial direction along the sloped face to return to the original position even when interference is generated between the driving gear and the cam of the pick-up gear.

Description

Pickup driving device of image forming device {APPARATUS FOR DRIVING PICK-UP OF PRINTER}

The present invention relates to a paper feeder of an image forming apparatus, and more particularly, to a pickup driving device of a paper feeder having an improved structure.

In general, an image forming apparatus performs a copying or printing process using printing paper and essentially includes a paper feeder on which a plurality of sheets are loaded, and a plurality of sheets from the paper feeder to the image forming unit side of the image forming apparatus. Pick-up driving device for picking up one by one in order to transfer the printing paper.

1 is a perspective view schematically showing a paper feeder of a generally used image forming apparatus.

The paper feeder 100 of the image forming apparatus includes a knock-up plate 1 on which a plurality of print sheets are stacked, a pickup shaft 3 mounted on the frame 2, and a pickup built up on the pickup shaft 3. A roller 5, a drive gear 6 arranged on an axis of a drive motor (not shown), a pickup gear 7 coupled to the pickup shaft 3 so as to be in gear with the drive gear 6, and the pickup gear And a solenoid (not shown) for constraining the rotation of the pickup gear 7.

The knock-up plate 1 is elastically supported toward the pickup roller 5 by the elastic support member 4. Therefore, when a sheet of paper is picked up and conveyed to the image forming portion side of the image forming apparatus, the sheet is brought up close by the gap.

The pick-up shaft 3 is rotatably mounted to the frame 2 via an bushing (not shown).

The pickup roller 5 is arranged in the pickup shaft 3 and is formed in a semi-cylindrical shape, and is located at the tip side of the printing paper to pick up the printing paper.

The drive gear 6 is arranged on the axis of the drive motor to transfer the driving force of the drive motor to the pickup roller 5 side.

The pickup gear 7 is connected to the drive gear 6 in gear coupling to receive the driving force from the drive motor to rotate the pickup roller 5 installed coaxially with the drive gear 6. A cam 8 is formed inside the pickup gear 7, which is integrally formed with the pickup gear 7.

The cam 8 is formed with a stopper 9 protruding outward on one side of the outer circumferential surface, and the cam 8 rotates at the same speed in the same direction as the pickup gear 7 rotates. Solenoids are provided on the lower side to restrain the rotation of (8).

Since the stopper 9 has a force to rotate in the same direction as the cam 8 about an axis, the cam 8 restrained by the stopper 9 when power is applied to the solenoid, The stopper 9 is released from the solenoid to release the restraint.

Thus, the pickup gear 7 formed integrally with the cam 8 is rotated.

When the power supply to the solenoid is cut off, the solenoid is brought back to an initial state, thereby being caught by the stopper 9 of the cam 8, thereby restricting the rotation of the pickup gear 7.

The paper pick-up and paper feeding process according to the above configuration will be described with reference to FIGS. 1 and 2A to 2C.

When printing paper is loaded on the knock-up plate 1, a pickup command is issued from the engine board by a sensor not shown in the drawing. Subsequently, when power is applied to the solenoid, the magnet becomes magnetic by the principle of the electromagnet, and the pickup gear 7 rotates while the solenoid is released from the stopper 9 of the cam 8.

When the pickup gear 7 rotates by the driving force of the drive motor in this way, the pickup roller 5 arranged coaxially with the pickup gear 7 rotates. The printing paper loaded on the knock-up plate 1 is transferred to the image forming unit side of the image forming apparatus by the pickup roller 5 which is rotated as described above.

In the conventional pickup driving apparatus 10 configured as described above, the pickup gear 7 is connected to the driving gear 6 to transmit a driving force by the driving motor. Conventionally, the cam 8 and the drive gear 6 of the pickup gear 7 are designed to be separated by a predetermined length in the shaft direction so as not to interfere with each other, but the error between the pickup shaft 3 and the bushing, the bushing and the frame 2 If the pickup shaft 3 is moved in the axial direction due to an error in the liver, interference may occur as shown in FIG. 2C.

As such, when interference between the cam 8 and the drive gear 6 of the pickup gear 7 occurs, tooth damage and noise of the drive gear 6 are generated, and thus it is necessary to improve it.

The present invention is conceived in view of the above, even if the pickup shaft is moved in the axial direction due to the assembly error of the pickup shaft, even if the interference between the cam and the drive gear of the pickup gear is rotated cam of the pickup gear It is an object of the present invention to provide a pickup driving apparatus of an image forming apparatus capable of preventing interference between a cam of a pickup gear and a driving gear by being moved to a position where this does not occur.

1 is a perspective view schematically showing a paper feeder of a general image forming apparatus;

2A and 2C are front views showing a conventional pickup driving apparatus of the image forming apparatus;

2B is a side view showing a conventional pickup driving apparatus of the image forming apparatus;

3A and 3B are a perspective view and a front view showing a pickup driving apparatus of the image forming apparatus according to the present invention;

4A to 4C show the operation of the pickup driving apparatus of the image forming apparatus according to the present invention.

<Description of Symbols for Major Parts of Drawings>

3: pickup shaft 5: pickup roller

20: pickup drive device 21: pickup gear

22: cam 23: stopper

23a: slope

Pick-up driving apparatus of the image forming apparatus according to the present invention for achieving the above object,

A drive gear which picks up sheet of printing paper from the sheet feeding unit by a pickup roller and feeds the sheet to the image forming unit of the image forming apparatus, the drive gear being constructed on the drive shaft of the driving motor and transmitting a driving force to the pickup roller side; A pickup gear meshed with the drive gear and rotatably mounted on the pickup shaft to receive the driving force of the drive motor; And a cam which is coaxially formed with the pickup gear and rotates integrally with the pickup gear, and has a stopper protruding from one side of the outer circumference thereof with an inclined surface formed to be inclined inwardly with a portion facing the pickup gear.

According to a preferred embodiment of the present invention, the cam is integrally formed with the pickup gear.

The above objects and other features will become more apparent by describing the preferred embodiments of the present invention in detail with reference to the accompanying drawings. For reference, in describing the embodiments of the present invention, the same reference numerals refer to the same parts as those in the related art.

As shown in Figs. 3A and 3B, the pickup driving device 20 of the image forming apparatus according to the embodiment of the present invention includes a drive gear 6 arranged on an axis of a drive motor (not shown), and the drive. A pickup gear 21 geared to the gear 6, a cam 22 fixed to the pickup gear 21, and a stopper 23 protruding from the outer circumferential surface of the cam 22.

The drive gear 6 is installed on the axis of the drive motor and is rotated by the drive motor to transfer the driving force to the pickup roller 5 side to be described later.

The pickup gear 21 is gear-connected with the drive gear 6 to receive a driving force, and is installed on the pickup shaft 3 installed in the frame 2 (see FIG. 1). A plurality of bushings (not shown) are fitted on the pickup shaft 3 to prevent their rotating frictional forces.

A cam 22 is formed on an inner surface of the pickup gear 21, and the cam 22 may be integrally formed with the pickup gear 21.

As described above, the driving force of the driving motor is transferred to the semi-cylindrical pickup roller 5 located above the leading end of the printing paper through the driving gear 6 and the pickup gear 21, and the image forming apparatus sheet by sheet. Is transferred to the image forming unit side.

The stopper 23 protruding outward from the outer circumferential surface of the cam 22 is formed to have an inclined surface 23a in the inward direction of the pickup gear 21. That is, the stopper 23 is formed in a trapezoidal shape in front thereof.

By the shape of the cam stopper 23 of the pickup gear 21 as described above, the cumulative error caused by various causes such as between the pickup shaft 3 and the bushing or between the bushing and the frame 2 during the printing process is also shown. Although the pickup shaft 3 is moved in the axial direction as shown in 4a, and interference occurs between the drive gear 6 and the cam of the pickup gear 21, the pickup gear 21 may be moved to the stopper 23. It moves finely in the axial direction along the inclined surface 23a and rotates to return to its original position.

Such a trapezoidal stopper 23 is caught by the solenoid to interrupt the rotation of the pickup roller (5).

An operation process of the paper feed unit 100 including the pickup driving device 20 having the above-described configuration will be described with reference to FIGS. 1 and 3A to 4C.

The paper feeder 100 is provided with a knock-up plate 1 on which a plurality of print papers are stacked, and the pickup roller 5 is placed on the pickup shaft 3 above the tip of the print paper loaded on the knock-up plate 1. It is built up. The pickup gear 21 and the cam 22 are arranged on the pickup shaft 3 on which the pickup roller 21 is arranged, and the pickup gear 21 is geared with the drive gear 6 of the drive motor. Connected to receive the driving force.

A solenoid (not shown) that is caught by a stopper 23 protruding from the cam 22 outer circumferential surface of the pickup gear 21 and intermittently rotates the pick-up roller 5 is movable with a catch portion that is caught by the stopper 23. And a plate, an elastic support member for elastically supporting the movable plate, and a solenoid portion having magnetic properties. When power is applied to the solenoid, the movable plate is in contact with the solenoid portion and the locking portion of the movable plate is separated from the stopper 23 to release the rotational restraint of the pickup roller 5.

Therefore, when printing paper is loaded on the knock-up plate 1, a pick-up command is issued from the engine board by a sensor not shown in the drawing, and when power is applied to the solenoid, the magnet becomes magnetic by the principle of the electromagnet. The movable plate is in contact with the top of the solenoid. Simultaneously, the cam stopper 23 of the pickup gear 21 is released from the engaging portion of the movable plate so that the pickup gear 21 is rotated.

When power is transmitted from the driving gear 6 from the driving mechanism of the pickup gear 21 as described above, and the pickup roller 5 rotates, the printing paper is transferred to the image forming unit side by the frictional force with the uppermost sheet, thereby printing. .

As the pickup roller 5 rotates as described above, when the pickup shaft 3 moves in the axial direction due to various causes, the interference between the cam 22 and the driving gear 6 of the pickup gear is as shown in FIG. 4A. This occurs, and as the pickup gear 21 rotates, the cam 22 integrally formed therewith also rotates. While the inclined surface 23a formed on the rotating cam 22 stopper and the driving gear 6 are in contact with each other, the pickup gear 21 is formed by the inclined surface 23a of the stopper as shown in FIGS. 4B and 4C. Returning to the position where the interference between the drive gear 6 and the pickup gear cam 22 does not occur.

The pickup driving device 20 of the image forming apparatus according to the present invention configured as described above is rotated and automatically eliminates the interference even if the interference between the drive gear 6 and the cam 22 of the pickup gear occurs.

As described above, according to the present invention, even if the shaft of the pickup gear moves in the axial direction due to various causes in the pickup driving apparatus of the image forming apparatus, the cam rotates even if interference occurs between the drive gear and the cam of the pickup gear. While being returned to its original position along the inclined surface of the stopper, interference between the drive gear and the pickup gear cam can be prevented, and thus damage to the drive gear teeth and occurrence of joints can be prevented.

While the invention has been shown and described in connection with preferred embodiments for illustrating the invention, the invention is not limited to the construction and operation as shown and described. Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims. Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

Claims (2)

A pickup driving apparatus of an image forming apparatus, which picks up sheet of printing paper from a sheet feeding unit by a pickup roller and feeds the sheet to an image forming unit of an image forming apparatus. A drive gear installed on a drive shaft of a drive motor and transmitting a driving force to the pickup roller; A pickup gear meshed with the drive gear and rotatably mounted on the pickup shaft to receive the driving force of the drive motor; And A cam configured to be coaxially formed with the pick-up gear and rotate integrally with the pick-up gear, and having a stopper protruding from one side of the outer circumferential surface thereof, the stopper having an inclined surface formed to be inclined inwardly. Drive system. The method of claim 1, wherein the cam, The pickup driving device of the image forming apparatus, characterized in that formed integrally with the pickup gear.