JPH0352742Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a paper feeding device used in a recording device, an image forming device, or the like.

[Prior art and problems]

2. Description of the Related Art Conventionally, in image forming apparatuses and the like, various paper feeding devices have been proposed for feeding sheets one by one and recording image information.

Generally, as shown in FIGS. 4a and 4b, a stacking plate 4 under a cassette 6 in which a large number of sheets 3 are stacked is supported by a spring 5, and a circumference provided on the top surface of the sheets 3 is used. This device uses a paper feed roller with a portion cut out and a separating claw 2 to convey one sheet at a time in one rotation.

The device having the structure described above has the advantages of a simple structure, easy control, low cost, and easy attachment and detachment of the cassette.

However, when the paper feed roller 1 having the notch rotates and a part of the circumferential surface of the paper feed roller comes into contact with the paper 3 and the circumferential surface rides on the paper 3, the paper feed roller 1 springs upwardly with the paper 3. In order to push down the biased loading plate 4 against the spring, a large load torque is applied to the drive shaft.

Further, due to the above-mentioned load torque, the drive source causes uneven rotation, which causes synchronization unevenness on images. Furthermore, in order to eliminate the above-mentioned uneven rotation of the drive shaft, it may be possible to use a drive source with a large rotational force (torque), but this has the drawback of increasing costs.

[Purpose of invention]

In view of the above-mentioned drawbacks of the conventional paper, it is an object of the present invention to provide a paper feeding device that equalizes fluctuations in the load torque of the drive shaft and is free from rotational unevenness and synchronization unevenness.

[Key points of the idea]

In order to achieve the above object, the present invention includes a paper stacking board for stacking paper, an elastic member that pushes up the paper stacking board, and a top and bottom paper on the paper stacking board that is pushed up by the elastic member. a drive shaft that rotates at a constant speed during rotation; a drive transmission means that transmits driving force from the drive shaft to the paper feed shaft; and a drive shaft that is fixed to the paper feed shaft. , has a cross-sectional shape in which a part of the circumference is cut out, and when the paper feed shaft is not rotating, the cutout portion maintains a predetermined distance from the topmost sheet of the stacked sheets, and one rotation of the paper feed shaft a paper feed roller whose circumferential portion comes into contact with the uppermost sheet of paper during each rotation to push the paper down from the first position to the second position against the force of the elastic member while feeding the paper; In the feeding device, the drive transmission means moves the uppermost sheet to the second position from the time when the circumferential portion of the sheet feeding roller first contacts the uppermost sheet when the sheet feeding shaft rotates. In order to gradually reduce the paper feeding rotational force by the paper feeding roller until it is pressed down from a first rotational force to a second rotational force, and to make the paper feeding rotational force after the second position to be the second rotational force, The present invention is characterized in that it includes a conversion mechanism that transmits uniform rotation from the drive shaft to the paper feed shaft as non-uniform rotation.

[Example of idea]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of the main parts of the paper feeding device of the present invention. The paper feeding device includes a paper feeding roller 11, a paper feeding shaft 12, an eccentric pulley 13, a paper 14, a claw member 15, a mounting plate 22, and a drive mechanism shown in FIGS. 2 and 3.

The paper feed roller 11 is fixed to a paper feed shaft 12, and an eccentric pulley 13 is fixed to the end of the shaft 12, and the whole is rotatable by support means (not shown).

Then, a paper feed roller 1 with a notch provided in a part
When the paper sheet 1 is stopped, the notch faces the uppermost sheet of sheets 14 stacked on the mounting plate 22 in parallel.

The placing plate 22 is urged upward by a spring (not shown), and the claw member 15 comes into contact with the uppermost sheet of paper, thereby restricting the upward movement of the sheet.

When the paper feeding roller 11 rotates and the paper 14 is pushed down, the claw member 15 follows the paper and comes into contact with the paper under its own weight. The eccentric pulley 13 has teeth on its circumferential surface, is fitted with a toothed belt (timing belt), and is driven by the toothed belt.

FIG. 2 is a diagram of the drive mechanism of the eccentric pulley 13.
(However, the view is from the back side).

The drive mechanism is composed of a drive pulley 16, a tension pulley 17, a toothed belt 21, and a spring clutch mechanism.

In the same figure, eccentric pulley 13 and drive pulley 16
are connected by a toothed belt 21, and a tension pulley 17 is urged upward to prevent the belt from sagging. Eccentric pulley 13 and drive pulley 16
The drive pulley 16 has the same circumferential length and the same number of teeth.
When the eccentric pulley 13 rotates once, the eccentric pulley 13 also rotates once.

FIG. 2 shows the state when the paper feeding roller 11 starts rotating and the peripheral surface of the roller is about to ride on the paper. At this time, the portion of the eccentric pulley having the largest amount of eccentricity from the center is configured to transmit the drive.

FIG. 3 is an assembled view of the spring clutch showing the rotation control mechanism of the drive pulley. The parts are coaxially assembled, and the boss part 18a of the drive gear 18 and one end of the clutch spring 19 fit together, and the boss part 16a of the drive pulley 16 and the other end of the clutch spring 19 fit together.

Circumferential protrusion A19a of clutch spring 19
is fitted into the groove 20a of the control tube 20, and the axially protruding portion B19b is fitted into the hole 16b of the drive pulley 16. In such a configuration, the drive gear 18 is connected to a drive source (not shown) and constantly rotates. A control member (not shown) is provided so as to be able to move in and out during the rotation trajectory of the protrusion 20b, and when the control member and the protrusion come into contact, the clutch spring does not transmit the rotational force, and when the protrusion does not come into contact and rotates freely, the clutch spring does not transmit the rotational force. conduct.

In the paper feeding device configured as described above, the protrusion 2 of the spring clutch is
When the control member 0b is released, the rotation of the drive gear 18 is transmitted to the drive pulley 16. Here, the relationship between the drive pulley 16 and the eccentric pulley 13 is configured as shown in FIG.
receives power at the eccentric part, and as the torque increases, the rotational speed decreases.

Therefore, even if a large torque load is applied, no fluctuation occurs.

In addition, since it rests on the loose paper, there is no risk of the paper slipping.

[Effect of idea]

As described above in detail, according to the paper feeding device of the present invention, fluctuations in the copying machine torque of the drive shaft can be reduced. Therefore, it is possible to prevent synchronization unevenness and image unevenness from occurring.

Further, when the paper feed roller comes into contact with the paper and rides on it, the rotation speed of the paper feed roller is low and the torque increases, so that the paper feed is stabilized and slips do not occur. Furthermore,
After the paper is completely mounted, the paper feed roller rotates at high speed, so the paper feed speed does not decrease.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of the paper feeding device of the present invention, FIG. 2 is a diagram of the drive mechanism of the eccentric pulley of the present invention, FIG. 3 is a diagram of the rotation control mechanism of the drive pulley of the present invention, and FIG. 4a and 4b are sectional views of main parts of a conventional paper feeding device. 11...Paper feed roller, 12...Paper feed shaft, 13...
Eccentric pulley, 14...paper, 15...claw member,
16a... Boss part, 16b... Hole, 17... Tension pulley, 18... Drive gear, 19... Clutch spring, 19a... Protruding part A, 19b... Protruding part B, 20... Control tube, 20a ...Groove, 20b...
... protrusion, 21 ... toothed belt, 22 ... mounting plate.

Claims (1)

[Claims for Utility Model Registration] A paper stacking board 22 on which papers 14 are stacked, an elastic member that pushes up the paper stacking board 22, and the uppermost paper on the paper stacking board 22 pushed up by the elastic member. means 15 for regulating the vertical position to the first position; a drive shaft 16a that rotates at a constant speed during rotation; and drive transmission means 16, 21, 13 that transmits driving force from the drive shaft 16a to the paper feed shaft 12. , which is fixed to the paper feed shaft 12 and has a cross-sectional shape in which a part of the circumference is cut out, and when the paper feed shaft 12 is not rotating, the cutout portion is attached to the uppermost sheet of the stacked sheets 14. A predetermined interval is maintained between the paper feed shaft 12 and the circumferential portion of the sheet during each rotation of the paper feed shaft 12, and the paper is moved from the first position to the first position against the biasing force of the elastic member. In a paper feeding device equipped with a paper feeding roller 11 that feeds paper while pushing it down to the second position, the drive transmission means 16, 21, 13 is configured to transfer the circumferential portion of the paper feeding roller 11 when the paper feeding shaft 12 rotates. The paper feed rotational force by the paper feed roller 11 from the time when the paper first contacts the top paper to the time when the paper feed roller 11 pushes down the top paper to the second position is expressed as a first
The rotational force is gradually reduced to 2 rotational force and the second
The method further includes a conversion mechanism 13 that transmits uniform rotation from the drive shaft 16a to the paper feed shaft 12 as a non-uniform rotation so that the paper feed rotational force after the position becomes the second rotational force. Characteristic paper feeding device.