JPH10147445A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a connection between a reverse shaft and a torque limiter from disconnecting by removing a reverse roller only when the reverse roller is replaced in a paper feeding device in which a specified torque is transmitted from the reverse shaft through the torque limiter to the reverse roller. SOLUTION: A connecting force at a connection part between a reverse shaft 7 and a torque limiter 6 is set larger than a connecting force at a connection part between the torque limiter 6 and a reverse roller 5. Thus, when the reverse roller 5 is pulled in the direction to disconnect it from the torque limiter 6 in order to replace the reverse roller 5, only the connection between the reverse roller 5 and torque limiter 6 is disconnected and the connection between the reverse shaft 7 and torque limiter 6 is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder having a double feed prevention function used in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, as a paper feeder used in an image forming apparatus such as a copying machine or a printer, Japanese Utility Model Publication No. 5-4298 is known.
No. 9, JP-A-5-319604, a feed roller that is driven to rotate in the sheet feeding direction, a reverse roller that contacts the feed roller, and a reverse shaft that is connected to the reverse roller via a torque limiter. And the like are known. According to such a sheet feeding device, when one sheet is fed between the feed roller and the reverse roller, the reverse roller is driven to rotate in the sheet feeding direction together with the feed roller to feed the sheet. . On the other hand, when two or more sheets are fed between the feed roller and the reverse roller, the reverse roller is driven to rotate in the direction opposite to the sheet feeding direction, and the second and subsequent sheets are fed into the sheet feed tray. The sheet is returned to prevent double feeding.

In such a paper feeder, the connection between the reverse shaft and the torque limiter is performed by fitting a pin fixed to the reverse shaft into a groove formed in the torque limiter. In addition, the connection between the torque limiter and the reverse roller is performed by fitting a fitting portion formed on the torque limiter with a fitting portion formed on the reverse roller. The connection between the reverse shaft and the torque limiter and the connection between the torque limiter and the reverse roller are easily released by applying a force in a direction away from the connected members. It has a structure. The reason is to facilitate maintenance when the reverse roller is deteriorated due to wear or when the torque limiter is deteriorated due to lack of grease.

[0004]

Recently, a torque limiter has been developed which has high durability without the need for grease, and its durability is several to ten times that of a reverse roller. Reach. Therefore, in most cases, the reverse rollers are replaced at the time of maintenance, and the torque limiter is rarely replaced.

[0005] However, when the serviceman pulls the reverse roller in the removing direction in order to replace the reverse roller, the connection between the torque limiter and the reverse shaft may be disconnected. The shaft must be connected, which is very troublesome.

In recent copiers and printers, a front-loading type paper feeder has become widespread. Since the paper feeder is arranged inside a main body case, it is dark and has poor visibility. Therefore, the serviceman may overlook that the torque limiter and the reverse shaft are disengaged from each other, and if left as it is, a double feed of paper or a jam occurs.

Accordingly, the present invention is to provide a paper feeder in which the connection between the torque limiter and the reverse shaft is not disconnected during maintenance for replacing the reverse roller.

[0008]

According to the first aspect of the present invention,
A feed roller that is driven to rotate in the sheet feeding direction, a reverse roller that contacts the feed roller, a reverse shaft that is driven to rotate in a direction opposite to the rotation direction of the feed roller, and that is connected to the reverse shaft and the reverse roller. And a torque limiter for transmitting a predetermined torque from the reverse shaft to the reverse roller, wherein a connecting force of a connecting portion between the reverse shaft and the torque limiter is increased by connecting the torque limiter to the reverse roller. It was set larger than the coupling force of the part. Therefore, when the reverse roller is pulled in a direction to disconnect the connection with the torque limiter in order to replace the reverse roller, the connection between the reverse roller and the torque limiter is released, but the connection between the reverse shaft and the torque limiter is not released, and the reverse roller is replaced. In this case, maintainability is improved.

According to a second aspect of the present invention, in the first aspect of the present invention, the connecting portion between the torque limiter and the reverse shaft is provided at a projection fixed to the reverse shaft and at an end of the torque limiter. The projection includes a groove in which the projection is fitted, and at least a part of the groove has a portion narrower than the diameter of the projection. Therefore, when the projection is fitted into the groove and the torque limiter and the reverse shaft are connected, at least a portion of the groove has a portion narrower than the diameter of the projection, so that the projection is less likely to come off the groove, and the reverse The coupling force between the shaft and the torque limiter can be increased by a simple structure.

[0010]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG. FIG. 2 is a side view showing the overall structure of a sheet feeding device used in an image forming apparatus such as a copying machine or a printer. A pickup roller 3 is disposed above a paper feed tray 2 that stores the paper 1, and a feed roller 4 and a reverse roller 5 are disposed downstream of the paper 1 picked up by the pickup roller 3 in the paper supply direction. ing. The feed roller 4 and the reverse roller 5 are arranged in parallel, and their outer peripheral surfaces are in contact with each other.

The feed roller 4 is driven to rotate in the direction of arrow A in order to feed the sheet 1 in the direction of the image forming section. The reverse roller 5 is connected to a reverse shaft 7 via a torque limiter 6, and the reverse shaft 7 is driven to rotate in a direction opposite to the rotation direction of the feed roller 4.

FIG. 1 is an exploded perspective view illustrating a connection state of the reverse roller 5, the torque limiter 6, and the reverse shaft 7. Reverse roller 5 and torque limiter 6
Are arranged in series, and a reverse shaft 7 is inserted through the reverse roller 5 and the torque limiter 6.
The torque limiter 6 is moved from the reverse shaft 7 to the reverse roller 5.
The outer case portion 8 is connected to the reverse shaft 7 and always rotates integrally with the reverse shaft 7.
And a core portion 9 fitted into the outer case portion 8 with a predetermined frictional force.

An elastically deformable resin knob 10 is formed at one end of the reverse roller 5, and the knob 10 is engaged with a ring groove 11 formed on the reverse shaft 7. The other end of the reverse roller 5 is formed with a plurality of protrusions 12 arranged on the same circumference. A plurality of protrusions 13 arranged on the same circumference are formed on a side surface of the core portion 9 of the torque limiter 6 facing the reverse roller 5. An engagement recess 14 is formed between the adjacent projections 13, and these engagement recesses 14 are formed.
Is formed slightly larger than the width “L2” of the projection 12, and the projection 12 is engaged with the engagement recess 14.

A boss 15 is formed on a side surface of the outer case portion 8 of the torque limiter 6 at a position surrounding the reverse shaft 7 inserted into the torque limiter 6. A groove 17 into which a pin 16 as a projection fixed to 7 is fitted is formed. This groove 1
7 is a chamfer 17a and a passage 17b as shown in FIG.
And a circular expanding portion 17c. Passage 1
The width of 7b is formed smaller than the diameter of the pin 16, and the diameter of the circular enlarged portion 17c is formed larger than the diameter of the pin 16.

In such a configuration, the reverse roller 5
And the torque limiter 6 and the reverse shaft 7 are connected by disposing the reverse roller 5 and the torque limiter 6 in series and engaging the projection 12 with the engagement recess 14, and then connecting the reverse shaft 7 with the torque limiter 6. This is performed by inserting the roller into the reverse roller 5. When the reverse shaft 7 is inserted through the torque limiter 6 and the reverse roller 5, the ring groove 11 has a knob 10.
Are engaged, and the pin 16 is fitted into the circular enlarged portion 17 c of the groove 17.

When replacing the reverse roller 5 that has deteriorated due to wear, the knob 10 is bent and removed from the ring groove 11, and the reverse roller 5 is pulled toward the tip of the reverse shaft 7 while maintaining the state. The reverse roller 5 and the torque limiter 6 are connected by engaging the projection 12 with the engagement recess 14, and the width dimension “L” of the engagement recess 14.
1 "is slightly larger than the width dimension" L2 "of the projection 12, so that the coupling force is almost" 0. "On the other hand, when the reverse shaft 7 and the torque limiter 6 are coupled, the pin 16 has a circular shape of the groove 17. This is performed by fitting the groove 1 with the expanding portion 17c.
Since the passage portion 17 b having a smaller width than the diameter of the pin 16 is formed in the pin 7, the pin 16 does not easily come off the groove 17.

Therefore, when the reverse roller 5 is pulled in the direction of the tip of the reverse shaft 7, the connection between the reverse roller 5 and the torque limiter 6 is easily released, without disconnecting the connection between the torque limiter 6 and the reverse shaft 7. Only the reverse roller 5 can be removed, and the maintenance performance when replacing the deteriorated reverse roller 5 is improved. Therefore, when the reverse roller 5 is replaced, the work of connecting the torque limiter 6 disengaged from the reverse shaft 7 does not occur, and the user does not notice that the connection between the torque limiter 6 and the reverse shaft 7 has been disconnected. Double feeds and jams do not occur because they are left unattended.

If the coupling force between the reverse shaft 7 and the torque limiter 6 is set to about 200 gf to 600 gf, when the torque limiter 6 needs to be replaced, the torque limiter 6 is connected to the reverse shaft 7. Can be easily extracted from

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. 1 to 3 are denoted by the same reference numerals. In the present embodiment, the connection between the reverse shaft 7 and the torque limiter 6 is performed by fitting a pin 16 fixed to the reverse shaft 7 into a groove 18 formed in the boss 15 of the torque limiter 6. . The groove 18 is formed between the chamfered portion 18a and the passage 1
8b, a circular enlarged portion 18c, and a cut portion 18d. The width of the passage 18b is smaller than the diameter of the circular enlarged portion 18c, and the diameter of the circular enlarged portion 18c is
6 is formed slightly smaller than the diameter.

Therefore, the pin 16 is connected to the circular expanded portion 1 of the groove 18.
8c, when the reverse shaft 7 and the torque limiter 6 are connected to each other, the inner peripheral surface of the circular enlarged portion 18c comes into pressure contact with the outer peripheral surface of the pin 16, and a force in the opening direction is always applied to the groove 18. Working. The groove 1 has a pin 1
6 has a passage portion 18b whose width is smaller than the diameter of the circular enlarged portion 18c in which the pin 1 is fitted.
6 hardly comes off the groove 18. Therefore, the reverse roller 5
Is pulled in the direction of the tip of the reverse shaft 7, the connection between the reverse roller 5 and the torque limiter 6 is easily released, and only the reverse roller 5 can be removed without disconnecting the connection between the torque limiter 6 and the reverse shaft 7. it can.

In each of the above-described embodiments, the case where the reverse roller 5 and the torque limiter 6 are directly connected to each other has been described as an example. However, the torque limiter 6 and the reverse roller 5 are connected for positioning or the like. When connecting via a spacer, the connecting force between the torque limiter 6 and the reverse shaft 7 is set to be greater than the connecting force between the spacer and the torque limiter 6.

[0022]

According to the first aspect of the present invention, the connecting force of the connecting portion between the reverse shaft and the torque limiter is set to be greater than the connecting force of the connecting portion between the torque limiter and the reverse roller. When pulling in the direction to disconnect the connection with the torque limiter for replacement, only the connection between the reverse roller and the torque limiter can be removed to maintain the connection between the reverse shaft and the torque limiter.
The maintainability when replacing the reverse rollers can be improved.

According to the second aspect of the present invention, the connecting portion between the torque limiter and the reverse shaft comprises a projection fixed to the reverse shaft and a groove provided at an end of the torque limiter and fitted with the projection, Since at least a part of the groove has a portion narrower than the diameter of the protrusion, the connecting force between the reverse shaft and the torque limiter can be increased by a simple structure.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a connection state of a reverse roller, a torque limiter, and a reverse shaft according to a first embodiment of the present invention.

FIG. 2 is a side view showing the overall structure of the sheet feeding device.

FIG. 3 is an enlarged front view showing a structure of a connecting portion between a torque limiter and a reverse shaft.

FIG. 4 is an enlarged front view showing a structure of a connecting portion between a torque limiter and a reverse shaft according to a second embodiment of the present invention.

[Explanation of symbols]

 4 Feed Roller 5 Reverse Roller 6 Torque Limiter 7 Reverse Shaft 16 Projection 17, 18 Groove

Continuation of front page (72) Inventor I ▼ Man ▲ Anji Ricoh Company, Ltd. 1-3-6 Nakamagome, Ota-ku, Tokyo

Claims (2)

[Claims] A feed roller that is driven to rotate in the sheet feeding direction; a reverse roller that contacts the feed roller; a reverse shaft that is driven to rotate in a direction opposite to the rotation direction of the feed roller; In a paper feeder having a torque limiter connected to a roller and transmitting a predetermined torque from the reverse shaft to the reverse roller, a connecting force of a connecting portion between the reverse shaft and the torque limiter is increased by the torque limiter and the torque limiter. A sheet feeding device characterized in that it is set to be larger than a connecting force of a connecting portion with a reverse roller. 2. A coupling portion between the torque limiter and the reverse shaft includes a protrusion fixed to the reverse shaft and a groove provided at an end of the torque limiter and fitted with the protrusion. 2. The paper feeder according to claim 1, wherein the paper feeder has a portion having a width smaller than a diameter of the protrusion.