JPH11322102A - Separating unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a service cost by improving exchangeability of a separating roller having a service life shorter than a feed roller, in a separating unit. SOLUTION: A unit structure 6 is composed of a integrally molded member such as a resin having a function supporting a feed roller 1 and a pickup roller 3 via a bearing member, an upper side paper guide function from the pickup roller 3 to an overlapped part of the feed roller 1 and a separating roller 2, further a function supporting a detection filler 9 and a function supporting a sensor 10, integrally molded products are also used as each function part and cost is remarkably reduced. The separating roller 2 is held on a lower side guide member 4 via a bearing and is pressurized by compression springs 8, 8 toward the feed roller 1. In the separating roller 2, a gear 11 is journalled by an E ring. If the E ring is removed, the separating roller 2 whose performance is lowered due to deterioration can be easily changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a separation unit used in an image forming apparatus such as a copying machine or a printer to separate and feed sheets in a sheet cassette one by one.

[0002]

2. Description of the Related Art As to a separation unit for separating and feeding paper, for example, as disclosed in Japanese Patent Application Laid-Open No. 54-24104, a feed roller having an uneven shape is provided. Separation rollers provided across the entire width of the paper to be rotated and conveyed are
There is one in which the other protrusion is inserted into one recess in a non-contact state with each other, and the two rollers are alternately arranged so as to overlap each other, so that the conveyance guide does not cause the paper to first contact the separation roller. .

In such a separation unit, since the life of the separation roller is shorter than that of the feed roller, it is desired to improve the exchangeability and reduce the service cost. In addition, it is desired to reduce the cost by integrating the functional components to reduce the cost, reduce the sheet conveyance resistance, and reduce the motor capacity.

[0004]

According to a first aspect of the present invention, there is provided a separation unit in which a feed roller for transporting a sheet and a separation roller for separating the sheet are arranged to face each other. Both rollers have uneven shapes, respectively,
In a separation unit in which the protrusion of the other roller enters the recess of one roller in a non-contact state with each other to form an overlapped portion, the separation roller is supported via a bearing so as to be movable toward the feed roller side. A lower guide plate, a pressurizing unit for pressing the separation roller against the feed roller via a bearing at a constant pressure, and a driving unit for rotating and driving the separation roller.

According to a second aspect of the present invention, there is provided a portion for supporting the feed roller and a pickup roller for calling the sheet via a bearing, and a sheet for guiding the sheet from the pickup roller portion to the overlap portion. An upper guide portion, and a portion that supports the sensor filler of the sheet positioned closer to the pickup roller and upstream of the feed roller and the separation roller in the sheet conveyance direction,
The unit body including a portion for holding a sensor for detecting that the upper surface of the sheet to be conveyed has reached an appropriate position together with the sensor filler is formed by a mold integral structure.

According to a third aspect of the present invention, a portion of the separation unit main body above the feed roller above the feed roller is the paper guide portion, and a surface of the upper portion that slides on the paper is a curved surface. I do.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing an embodiment of the separation unit according to the present invention, and FIG. 2 is an enlarged sectional view showing an arrangement relationship between a main part of the separation unit of FIG. 1 and a paper cassette. In the drawing, reference numeral 1 denotes a feed roller, in which a resin cylindrical member is fixed to a metal shaft, and at least two or more ring-shaped EP rubbers are mounted on the outer periphery thereof by press-fitting or the like. Then, as shown in FIG. 2, the feed roller 1 is arranged on the side that comes into contact with the upper surface of the sheet P fed from the sheet cassette 20.

[0010] In the drawing, reference numeral 2 denotes a separation roller. Similar to the feed roller 1, a resin cylindrical member is fixed to a metal shaft, and a ring-shaped urethane rubber is mounted around the outer periphery thereof by press-fitting or the like. As shown in FIG. 2, at least one ring is attached to the separation roller 2 so as to form a pair with the feed roller 1 and to be in contact with the back surface of the paper P so that the ring portions of the rollers are alternated. ing.

As can be seen from FIG. 2, each of the ring portions of the feed roller 1 and the separation roller 2 has a shape that overlaps with the shaft of the counterpart roller by a dimension 1 without contact.

In FIG. 1, reference numeral 3 denotes a pickup roller, and the material of the roller is EP rubber, like the feed roller 1. The pickup roller 3 also has a resin cylindrical member held on a metal shaft via a one-way bearing, and EP rubber is press-fitted to the outer periphery of the resin cylindrical member. As shown in FIG. 2, the pickup roller 3 is disposed in the area of the leading end portion of the sheet P in the cassette 20, and the uppermost sheet P
Used for sending out.

In the drawing, reference numeral 4 denotes a lower guide member for feeding the paper P, and both ends are held by the unit structure 6. The separation roller 2 is movably held by the lower guide member 4 via a bearing, and is pressed toward the feed roller 1 by compression springs 8, 8. A gear 11 is engaged with the separation roller 2 by a D hole and is axially fixed by an E-ring or the like. Therefore, by removing the E-ring or the like from this state, the separation roller 2 that has deteriorated and the performance has been reduced can be easily replaced.

The lower guide member 4 has a reference pin or a reference hole integrally formed on both side surfaces. The reference pin of the lower guide member 4 is inserted into the reference hole provided in the unit structure 6, and the face plate 5 (the reference pin is protruded) is pressed from the other side to the reference hole of the lower guide member 4. The lower guide member 4 and the unit structure 6 are positioned by being inserted and engaged with the positioning holes of the unit structure 6. The face plate 5 is fixed with screws.

In the figure, reference numeral 12 denotes a relay gear for transmitting the rotational force transmitted via the shaft 7 to the gear 11. In the figure, 13 is a driven gear, 14 is a feed roller drive gear, and the feed roller drive gear 14 is connected to a gear on the main body (not shown) to be rotationally driven, and transmits its rotational force to the feed roller 1. The driven gear 13 receives a rotational force from the feed roller drive gear 14 and transmits the rotational drive of the shaft 7. In the figure, reference numeral 15 denotes a pulley, which transmits a rotational force to the pulley 16 via a timing belt 17. In the figure, reference numeral 18 denotes a shaft, which is connected to the metal shaft of the pickup roller 3 by coupling or the like.
Here, if the life of the pickup roller 3 is sufficient, there is no problem even if the shaft 18 and the metal shaft of the pickup roller 3 are integrated.

In the drawing, reference numeral 9 denotes a detection filler,
0 informs the sensor 10 that the bottom plate (not shown) has risen and the upper surface of the uppermost sheet P has reached the proper position. The sensor 10 detects the fact that the detection filler 9 rotates in response to the rising of the sheet and reaches a proper position, and sends a signal. As a result, a lift motor (not shown) stops.

The unit structure 6 has a function of supporting the feed roller 1 and the pickup roller 3 via a bearing member, and an upper paper guide function from the pickup roller 3 to the overlap portion of the feed roller 1 and the separation roller 2. Further, it is an integrally molded member such as resin having a function of supporting the detection filler 9 and a function of supporting the sensor 10. By doing so, each functional component is also used as an integrally molded product, and significant cost reduction is achieved. Further, by forming the upper front surface of the feed roller 1 into a paper guide shape and forming an R-curved surface, the conveyance resistance of the paper can be greatly reduced, the motor capacity on the apparatus main body side can be reduced, and the cost can be reduced.

Next, the operation of this embodiment will be described. First, when the rotational force of the drive gear (not shown) is transmitted to the gear 14, the feed roller 1, the separation roller 2, and the pickup roller 3 rotate via the gear train, pulley 15, and timing belt 17 described above. .

As shown in FIG. 2, the uppermost sheet P in the sheet cassette 20 is fed by the pickup roller 3 in the nip direction of the feed roller 1 and the separation roller 2. When one sheet of paper P is sent, the friction coefficient between the feed roller 1 and the sheet P is larger than the friction coefficient between the separation roller 2 and the sheet P, so that the sheet is conveyed as it is, and a registration roller unit (not shown) The tip is sent to. When this is detected by a sensor (not shown), the paper P is temporarily stopped. Thereafter, the sheet P is sent out from the registration unit at a timing such that the leading edge of the sheet P matches the leading edge of the image. At this time, since the driving of the sheet feeding device is cut off, the feed roller 1 is rotated by the feeding force of the sheet P. At this time, the rotation is transmitted to the separation roller 2 in the order of the feed roller drive gear 14, the driven gear 13, the relay gear 12, and the gear 11. Therefore, even if the sheet located below the uppermost sheet reaches the nip between the feed roller 1 and the separation roller 2, the sheet is prevented from entering the nip.

The one-way bearing is press-fitted into the pickup roller 3 because the pickup roller 3 does not act as a brake for feeding the paper P, in other words, does not apply an excessive load to the registration roller. This is to prevent the shaft from being subjected to rotation in the clockwise direction in the drawing. When the bottom plate of the paper cassette 20 is raised by a lifting motor (not shown) and the detection filler 9 cuts off the sensor 10, it is detected that the paper P has reached an appropriate position, and the lifting motor stops.

After the sheet P is conveyed by the registration rollers and the trailing end of the sheet passes through the pickup roller 3, the sheet positioned under the conveyed sheet P is moved by the rotational force of the feed roller 3 as described above. In order to prevent the pick-up roller 3 rotating from being transmitted, the pick-up roller 3 releases or spins the sheet except when the pick-up roller 3 feeds the paper to the overlap portion of the feed roller 1 and the separation roller 2. It is also possible to use.

[0020]

Since the separation unit according to the first aspect is as described above, the exchangeability of the separation roller having a shorter life than the feed roller is improved, and the service cost can be reduced.

Since the separation unit according to the second aspect is as described above, in addition to the above-mentioned common effects, there is an effect that the cost can be reduced by integrating the functional components.

Since the separation unit according to the third aspect is as described above, in addition to the above-described common effects, there is an effect that the sheet conveyance resistance can be reduced, the motor capacity can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a separation unit according to the present invention.

FIG. 2 is an enlarged sectional view showing an arrangement relationship between a main part of the separation unit of FIG. 1 and a paper cassette;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 feed roller P paper 2 separation roller 3 pickup roller 4 lower guide member 5 face plate 6 unit structure 7 shaft 8 compression spring 9 detection filler 10 sensor 11 gear 12 relay gear 13 driven gear 14 feed roller drive gear 15, 16 pulley 17 Timing belt 18 axis 20 paper cassette

Claims (3)

[Claims] 1. A feed roller for transporting a sheet and a separation roller for separating the sheet are arranged to face each other, each roller has an uneven shape, and a concave portion of one roller is in a non-contact state with a convex portion of the other roller. And a lower guide plate for supporting the separation roller via a bearing so as to be movable toward the feed roller side, and the separation roller for feeding the separation roller via a bearing. A separation unit comprising: a pressurizing unit that presses a roller with a constant pressure; and a driving unit that rotationally drives the separation roller. 2. A portion for supporting a feed roller and a pickup roller for calling a sheet via a bearing, an upper sheet guide portion for guiding a sheet from the pickup roller portion to the overlap portion, and the pickup. A portion that supports the sensor filler of the paper that is closer to the rollers and that is located upstream of the feed rollers and the separation rollers in the paper transport direction, and that the upper surface of the paper to be transported is at the proper position. 2. The separation unit according to claim 1, wherein a unit main body including a part holding a sensor to be detected is formed by a mold integral structure. 3. The separation unit according to claim 2, wherein a portion of the separation unit main body above the feed roller is forward and the sheet guide portion is formed, and a surface of the upper portion that slides on the sheet is a curved surface. .