JP3329938B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for separating and feeding sheets one by one from a sheet bundle, which is applied to an image forming apparatus such as a copying machine, a facsimile, and a laser printer.

[0002]

2. Description of the Related Art In an image forming apparatus, a so-called friction separation system is widely known and employed as a mechanism for separating sheets one by one from a sheet bundle. In this system, a member for feeding out the top or bottom sheet of a sheet bundle and a member for preventing the conveyance of another sheet fed out along with the sheet, that is, a member for preventing a so-called double feed, are used as basic members. The separation is performed using the difference between the friction coefficient between both members and the paper and the friction coefficient between the papers.

Some of the members for preventing double feed and separating sheets are of a fixed type. For example, JP-A-3-1
JP-A-8531 discloses a long separation belt facing a paper feed roller rotatable around an axis.

[0004] If the sheet feeding / separation is repeated by the blocking member of this type, the blocking member deteriorates due to friction with the original bundle or adhesion of dirt, so that the blocking member needs to be replaced.

[0005]

Therefore, in order to extend the life of the blocking member, the blocking member is formed in the form of an endless belt, and the blocking member is moved little by little to reduce the abrasion at the nip portion of the sheet separation. Known are those that are dispersed.

As a method of replacing such a belt-like blocking member, a blocking member drive shaft bracket at the tip of the blocking member drive shaft is first removed, and the blocking member support is slid in the thrust direction along the shaft. There is a method of removing the blocking member together with the support from the tip end of the drive shaft, and removing the driven member attached to the support to remove the blocking member.

[0007] The separation belt used as a sheet blocking member used for sheet separation is in contact with the sheet from beginning to end, and if used for a long time, deteriorates due to wear or contamination of the belt surface. After a certain period, the separation belt needs to be replaced. in this case,
Although the separation belt has a rotating structure, dirt and load are dispersed and product life is improved,
The structure for mounting the members becomes complicated, which causes a problem that it is difficult to easily replace the belt. When the separation belt bracket, which is the support of the separation belt, is removed as described above, the following two steps are required for belt replacement.

[0008] 1. Remove the separation belt together with the separation belt bracket from the automatic paper transport device.

[0009] 2. Remove the separation belt from the separation belt bracket.

Conventionally, it is necessary to loosen the set screw when removing the drive shaft bracket in the initial stage.
In the next stage, an operation of removing an E-ring or the like is necessary for disassembling the separation belt bracket.

However, as the assembly labor or the labor cost for the service rises, the necessity of shortening the assembling time and the service time by improving the assemblability and serviceability of the image forming apparatus has been increasing. In particular, there is a demand for a structure that allows service parts to be assembled without tools such as a screwdriver.

In view of the above-mentioned demands, the present invention makes it possible to replace the separation belt portion of the paper feeder without requiring any tools, greatly improving assemblability and serviceability, and improving high reliability. It is an object to provide a paper feeder realized at low cost.

[0013]

According to the present invention, there is provided, in accordance with the present invention, a feeding means for feeding a sheet in a feeding direction, and an endless belt for rubbing the feeding means to prevent double feeding. And a sheet feeding device for feeding sheets one by one from the bottom or top of a plurality of stacked sheets, the separation means being provided at both ends of the support. One roller member is connected to a drive shaft, and the other roller member is movable along a guide portion formed on the support and is used as a pressing means for applying tension to the separating means. The support is engaged with the drive shaft via the bearing by the tension of the pressurizing means, and the tension of the separating means is relaxed by moving the roller member against the pressing force of the pressurizing means. , So that the engagement between the support and the drive shaft is released. It is.

A driven shaft inserted into the roller member is slidable on a guide portion of the support, and the pressing means held and regulated by a positioning portion formed on the guide portion is engaged with the driven shaft. It is preferable if it is done.

Further, it is more convenient if the partial surface of the support constitutes a guide portion for conveying the sheet.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on embodiments shown in the drawings.

FIG. 1 shows an automatic document feeder / reversing device equipped with a paper feeding device according to the present invention, wherein a document feeding mechanism is located on the left side of the drawing, and a reversing / discharging mechanism is located on the right side of the drawing.

A document table 28 is provided at an upper central position of the automatic document feed / reversing device, and a document discharge unit 31 is provided below the document table 28. In the document feeding mechanism, the feeding roller 1, the feeding roller 7, and the separation belt 6 that abuts against the same, the driving roller 8 and the driven roller 5 that hang the belt, the pull-out driving roller 10, and the driven roller 11 that abuts against the same. Are provided at predetermined positions, and a document pressing lever 2, a document set detecting filler 3, and a document stopper 4 that can be pressed against the call roller 1 are coaxially mounted.

Between the document discharge section 31 and the contact glass 18 located below the automatic document feed / reversing device, there is a transport belt 17 stretched over a driving roller 14 and a driven roller 19, and A plurality of conveyor belt pressing rollers 16 are disposed so as to contact the lower inner surface.
At the left end of the contact glass 18 as seen in the figure, a reference scale 29 for the one-sided contact mode is attached.

In the reversing / discharging mechanism, the reversing driving roller 20 and the reversing entrance driven roller 21 and the reversing exit driven roller 25 abutting on both ends thereof, the guide roller 23, the switching claw 24, respectively.
A paper discharge drive roller 26 and a paper discharge driven roller 27 that is opposed to and abuts the paper discharge drive roller 26 are respectively provided at predetermined positions.

As for the conveyance operation, in the case of one-sided copying, the size of the width direction is detected by the detection sensor 9 and the size of the conveyance direction is detected by the registration sensor 13 when passing through a document feeding mechanism which will be described in detail later. After the original is stopped at a predetermined position on the contact glass 18 by the transport belt 17 and exposed, the reversing drive roller 20 and the reversing entrance driven roller 2
1 and travels along the conveyance path in the reversing / discharging mechanism, and is discharged to the document discharge unit 31 through between the discharge rollers 26 and 27.
In the case of double-sided copying, the document whose size has been detected is first conveyed as it is on the contact glass 18 by the conveyance belt 17 and guided to the conveyance path in the reversing / discharging mechanism. The sheet is conveyed to a predetermined position on the contact glass 18 by the conveyance belt 17 which is reversed in a reversing manner by the reversing path between the reversing exit driven rollers 25, and is rotated in reverse at the same time. And the surface is exposed, and is discharged to the document discharge section 31 through the reversing / discharging mechanism.

Here, the operation of the paper feeding system will be described. Place the stack of originals on the original table 28 with the front side facing up,
The document is set so that the leading edge of the document abuts on a document stopper 4 at the entrance of the sheet feeding unit (which is lifted up in FIG. 1 but is lowered at the time of setting). In such a state, since the document bundle lifts the document set detection filler 3, the document set detection sensor 12 detects that a document is present on the document table 28. When the copy start button on the operation panel (not shown) is pressed and a document feed signal is issued, the press lever 2 is moved to the recall roller side by the control mechanism (not shown) to move the document bundle with the roller 1. The document stopper 4 is released while being held and pressed, and the position of FIG.

After the document stopper 4 is released, when a paper feed motor (not shown) rotates in a predetermined direction, the calling roller 1, the feeding roller 7, and the pull-out driving roller 10 are driven via the respective transmission mechanisms. Due to the rotation of the page roller 1, the bundle of documents set on the document table 28 is transported to a position where it hits the separation belt 6. In the document hitting the separation belt 6, the lowermost sheet and other sheets are friction-separated by the feeding roller 7 and the separation belt 6. At this time, since the power is not transmitted by the one-way clutch (not shown) in the transmission mechanism, the separation belt is in a stopped state.

The separated lowermost sheet is conveyed by the feed roller 7 and the pull-out roller pair 10, 11. When the leading edge of the conveyed document is detected by the registration sensor 13 disposed downstream of the pull-out driving roller 10, the sheet feeding motor stops and the document is stopped at a predetermined position.

Thereafter, at the same time as the sheet feeding motor rotates in the reverse direction, the transport motor (not shown) also rotates. The pull-out driving roller 10 and the separation belt driving roller 8 are driven by the rotation of the sheet feeding motor via the respective transmission mechanisms. Due to the rotation of the separation belt driving roller 8, the separation belt 6 stopped at the time of separation rotates in the direction opposite to the document conveying direction. The call roller 1 and the feed roller 7 can be rotated in the document conveying direction by a one-way clutch in a transmission mechanism (not shown). By the rotation of the transport motor,
The transport belt driving roller 14 is driven, and the transport belt 17 rotates so as to transport the document to the right in FIG.

Since no driving force is generated in the feeding roller 1 and the feeding roller 7 and the separation belt 6 rotates in the direction opposite to the document conveyance direction, the entry of the next document into the separation nip portion is prevented, and the conveyance of the next document is performed first. The fed document is transported from the paper feeding unit to the transport unit by the rotation of the pull-out roller pair and the transport belt.

FIG. 2 shows a belt section for separating and feeding a document. As shown in FIG. 1, an endless separation belt 6 is a belt bracket 5 having one end locked to a belt drive shaft 51.
It is supported by 2. As shown in FIG. 3, the drive roller 8 for rotating and driving the separation belt has one end fitted to a D-shaped portion 51a of a belt drive shaft 51 held on a shaft bracket 61 via a stepped bearing 54. To the drive shaft 51 so as not to rotate. A stepped bearing 54 is also attached to the other end of the driving roller 8 that is fitted to the belt drive shaft 51 and fixed in position by the shaft bracket 61, and the fixing ring 55 is fitted into the notch 51 b of the drive shaft 51. As a result, the sliding of the driving roller 8 in the axial direction is prevented.

As shown in FIG. 4, when the separation belt 6 is attached to the belt bracket 52, the pin 57 formed on the notch sliding portion on both side surfaces of the belt bracket 52 on the driven portion side is attached to the pin 57. Longer compression springs 53 are respectively inserted and supported. At both ends of the compression spring 53 opposite to the pin side, both ends of a driven shaft 56 inserted in the belt driven roller 5 are fixed, and the driven shaft 56 and the driven roller 5 It slides according to and against the pressing force. At both ends of the driven roller 5 fitted to the sliding shaft 56, flanges for preventing the belt from coming off are formed, and when the driven roller 5 and the driven shaft 56 are attached to the belt bracket 52, they are separated. The belt 6 is also wound.

As described above, when the belt bracket 52 having the driven portion side is attached to the belt drive shaft 51, the driven roller on the driven portion side is pushed into the notch sliding portion of the belt bracket, as shown in FIG. After the other end of the separation belt 6 is wound around the drive roller 8, the drive portion side concave engagement portion 52 a of the belt bracket 52 is engaged with the small diameter portion of the bearing 54 at both ends of the drive roller 8. Will be When the compression spring 53 attempts to return to its original state, the separation belt 6 is placed in tension between the driving roller 8 and the driven roller, and the entire belt portion is fixed.

FIG. 6 shows the surface of the belt portion facing the feed roller. When the feeding roller side of the belt bracket 52 is open, the separation belt 6 comes into contact with the feeding roller and can rub against the roller. Further, a paper guide surface 52b is formed on the upper portion of the belt bracket 52, and is used for stable document conveyance.

With the above configuration, the belt portion can be easily assembled and removed without using any tools. At the time of removal, the belt driven roller 5 is pushed into the notched sliding portion of the belt bracket to bend the separation belt 6, and in this state, the belt bracket 52 is detached from the bearing 54 and shifted in the thrust direction. Remove the belt.

Although the above embodiment has been described as a document feeder, it is very obvious to those skilled in the art that the present invention is applied to a transfer paper feeder.

[0033]

According to the paper feeder of the first aspect, the separating means is stretched over the two roller members disposed at both ends of the support, one of which is connected to the drive shaft and the other of which is connected to the drive shaft. The roller member is movable along a guide portion formed on the support and is pressed by a pressurizing means for applying tension to the separating means, and the support is engaged with the drive shaft via a bearing by the tension of the pressurizing means. It is configured so that the tension of the separating means is relaxed by moving the roller member against the pressing force of the pressing means, and the engagement between the support and the drive shaft is released. Since the separating means is integral with the support on which the means is suspended and can be easily mounted on and removed from the paper feeder without using special tools, the ease of assembly and serviceability is greatly improved. .

According to the paper feeder of the second aspect,
A driven shaft that is inserted into the roller member is slidable on a guide portion of the support, and the pressing unit that is held and regulated by a positioning portion formed on the guide portion is engaged with the driven shaft. Therefore, in addition to the effect of the first aspect, assembling on the driven side of the belt portion is possible without any special fastener.

According to the paper feeder of the third aspect,
Since the partial surface of the support forms a guide portion for transporting the paper, in addition to the effects of the first and second aspects, it is possible to supplement a paper guide which is often insufficient in the automatic paper feeder, and to form a paper bundle. Unnecessary contact with the separating means can be reduced, problems such as breakage of the leading edge of the sheet can be prevented, and the sheet transportability can be stabilized.

[Brief description of the drawings]

FIG. 1 is a schematic view of an automatic document feeding / reversing device equipped with a paper feeding device according to the present invention.

FIG. 2 is a schematic perspective view of a belt unit.

FIG. 3 is a schematic perspective view illustrating an attached state of a belt driving roller to a driving shaft.

FIG. 4 is a partial schematic perspective view illustrating an assembling configuration of a belt portion on a driven portion side.

FIG. 5 is a schematic perspective view for explaining an assembling configuration of a belt portion on a driven portion side.

FIG. 6 is a schematic view showing a feeding roller side of a belt unit.

[Explanation of symbols]

 6 Separation belt 8 Drive roller 52 Belt bracket 52a Concave engagement part 53 Compression spring

────────────────────────────────────────────────── ─── Continuing from the front page Examiner Norio Nakamura (56) References JP-A-1-267226 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B65H 1/00-3 / 68

Claims (3)

(57) [Claims] A feeding unit for feeding a sheet in a feeding direction;
Endless belt-shaped separating means for preventing double feeding by rubbing the feeding means, and feeding the sheets one by one from the bottom or top of a plurality of stacked sheets. In the apparatus, the separating means is stretched over two roller members disposed at both ends of the support, one of which is connected to a drive shaft, and the other is along a guide formed on the support. The support is engaged with the drive shaft via a bearing by the tension of the pressurizing means, and is pressed by the pressurizing means to apply tension to the separating means. A sheet feeder, wherein the tension of the separating means is relaxed by moving the roller member in opposition, and the engagement between the support and the drive shaft is released. 2. The driven shaft, which is inserted into a roller member, is slidable on a guide portion of the support, and the pressing means, which is held and regulated by a positioning portion formed on the guide portion, is provided on the driven shaft. The sheet feeder according to claim 1, wherein the sheet feeder is engaged. 3. The sheet feeder according to claim 1, wherein the partial surface of the support forms a guide portion for conveying the sheet.