JPH08268571A - Paper feeder and image reader and image forming device - Google Patents

Abstract

PURPOSE: To provide a paper feeder by which the sheet tip can be easily adjusted to a proper position by arranging a checking member to check the sheet tip when a user manually inserts plural sheets. CONSTITUTION: A checking member 12a to check so that the tip of a sheet to be inserted into a clearance between a pressing member 5 and a rotary member 3 cannot be inserted more than a specific quantity is arranged on the downstream side in the carrying direction of the rotary member 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device used in, for example, a copying machine, a printer, a facsimile and the like, an image reading apparatus using the same and an image forming apparatus.

[0002]

2. Description of the Related Art A conventional paper feeder will be described with reference to FIGS.

In FIG. 10, 201 is a separation roller for separating a plurality of stacked sheets of sheet material, and 2 is a separation roller.
Reference numeral 02 denotes a separating piece constituted by an elastic member so as to stop the sheet material which is not separated by coming into contact with the separating roller 201. Reference numeral 203 denotes a pre-conveying roller that collectively conveys the stacked sheet materials and separates the sheet materials from the separation roller 201.
And guide it until it contacts the separation piece 202. 204a and 204b
Are a paper edge sensor lever and a paper edge sensor, respectively, and the detection unit of the paper edge sensor 204b is operated by the tip of the sheet material hitting the paper edge sensor lever 204a and pushing it.

Reference numeral 207 is a solenoid supported by the frame 212, and 205 is a plunger reciprocally driven by the solenoid 207.
It is connected to one end of a pendulum arm 209 which is swingably supported by 0 through a pin 208. At the other end of the pendulum arm 209, the preliminary conveyance roller 203 is rotatably supported via a rotary shaft 211, and a pressing spring 206 is provided between the pendulum arm 209 and the frame 212.
Is urged to lift up.

Further, as shown in FIG. 11, 213 is an upper guide for guiding the upper surface of the sheet material P, and 205 is the sheet material P.
Is a lower guide that guides the lower surface of the.

Next, the sheet feeding operation will be described with reference to FIGS.

FIG. 10 is a sectional view showing a standby state, in which the plunger 205 pushes the pin 208. Here, since the rotary shaft 210 is rotatably held by the device and the rotary shaft 211 is rotatably held by the pendulum arm 209, when the pin 208 is pushed upward as shown in FIG. The pendulum arm 209 swings to lower the pre-transport roller 203. Then, the pre-conveyance roller 203 is hidden by the lower surface of the lower guide 215, a space is formed between the upper guide 213 and the lower guide 215, and the sheet material P can be inserted into this space.

As shown in FIG. 11, when the sheet material P is set, the leading edge of the sheet material P hits the paper edge sensor lever 204a and pushes it, and the paper edge sensor 204b confirms that the sheet material P has been set. Detect. Then, the solenoid 207 is excited by the detection signal from the paper edge sensor 204b, and the plunger 205 moves downward as indicated by the arrow in FIG. As a result, the force pushing down the preliminary conveyance roller 203 is released, and the preliminary conveyance roller 203 lifts the sheet material P by the pressing spring 206, and the upper guide 2
Sandwich with 13. In this state, the rotational driving force is transmitted from the drive source (not shown) to the separation roller 201 and the pre-conveyance roller 203, and the separation conveyance of the sheet material P is started one by one.

When all the sheet materials P have been conveyed,
The paper edge sensor lever 204a returns to the state of FIG. 10, and the paper edge sensor 204b detects "no sheet material P". When this happens, de-energize the solenoid 207 and
The preliminary conveyance roller 203 is again pushed down and held.

Such a configuration is, for example, a real fair 1-2.
It is described in Japanese Patent No. 6667 and Japanese Utility Model Publication No. 3-30353.

[0011]

However, in the above-mentioned conventional structure, in the standby state in which the preliminary conveying roller 203 is lowered,
When a large gap is provided at the entrance of the sheet material to improve the loading property, the following problems occur.

First, since there is no sense of abutting when inserting the sheet material P, the user may not know how far the sheet material P may be inserted, and the tip position of the sheet material P may vary.

Secondly, when the user inserts the sheet material P extremely quickly, the front end portion of the sheet material P is moved to the preliminary conveyance roller 2.
03 The sheet material P cannot be completely separated because it has passed over the contact portion between the separation roller 201 and the separation piece 202 on the downstream side, and a plurality of sheets are sent together.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to:
An object of the present invention is to provide a sheet feeding device that can easily align the leading edge of a sheet at an appropriate position by providing a blocking member that holds the leading edge of the sheet when the user manually inserts a plurality of sheets.

The second object is to achieve the first object by the cheapest means.

A third object is that the pressing of the sheet by the rotating member can be released when a driving force opposite to the direction in which the sheet is conveyed to the rotating member such as the preliminary conveying roller is transmitted, and the pressing of the solenoid or the like is exclusively used. It is intended to reduce the cost by omitting the electric parts.

A fourth object is to securely stop the sheet by moving the stopper member between the stopper position and the retracted position, and further drive the stopper member similarly to the pressing release operation of the rotating member. It is intended to reduce the cost by mechanically connecting with the drive of the device and operating it.

A fifth object is to automatically release the pressing of the sheet by the rotating member when the operation of the sheet feeding device is normally completed, and return the sheet to a state in which the next sheet can be easily loaded.

A sixth object is to automatically release the pressing of the sheet by the rotating member when the operation of the sheet feeding device is not normally completed, and return the sheet to a state in which the next sheet can be easily loaded. is there.

[0020]

In order to achieve the above object, in the present invention, a rotating member for conveying a sheet,
A pressing member provided so as to come in contact with and away from the rotating member, a pressing releasing means for separating the pressing member and the rotating member, and a gap for inserting the sheet therebetween, and a driving means for rotationally driving the rotating member. And a sheet inserted into the gap between the pressing member and the rotating member, which is sandwiched between the rotating member and the pressing member and conveyed, inserted into the gap between the pressing member and the rotating member. A stop member is provided on the downstream side of the rotating member in the conveyance direction so as to prevent the front end of the sheet from being inserted by a predetermined amount or more.

The stopping member is in a position where the leading end of the sheet is stopped when the pressing member and the rotating member are separated from each other, and is in a position where the leading end of the sheet is not stopped when the sheet is conveyed by the pressing member and the rotating member. And

The stop member is a part of a guide member for guiding the lower surface of the sheet.

The pressing releasing means maintains the pressing member in a pressed state against the rotating member when the driving means generates a driving force in the direction in which the rotating member conveys the sheet to the downstream side. When the driving means generates a driving force that rotates in a direction opposite to the direction in which the sheet is conveyed to the downstream side, the pressing of the pressing member against the rotating member is released, and a predetermined distance is provided between the pressing member and the rotating member. It is characterized in that a gap is formed.

The restraining member is movable to two positions, a restraining position for restraining the sheet and a retracting position for permitting the passage of the sheet, and the driving force in the direction in which the rotating member conveys the sheet to the downstream side. When the drive means is generated, the braking member is retracted from the braking position to the retracted position, and when the driving means generates a driving force in a direction opposite to the direction in which the rotating member conveys the sheet to the downstream side. The blocking member is configured to stand by at the blocking position.

A detection means for detecting the presence or absence of the sheet is provided,
After detecting that the conveyance of the sheet is completed by the detection means, drive the drive means in a direction opposite to the direction in which the rotating member conveys the sheet to the downstream side, and activate the press release means. A gap is formed between the rotating member and the pressing member.

When the detecting means detects that the sheet is not conveyed normally, the rotating means causes the driving means to drive in the direction opposite to the direction in which the rotating member conveys the sheet to the downstream side. It is characterized in that a gap is formed between the rotating member and the pressing member by operating the pressing releasing means.

On the downstream side of the rotating member in the conveying direction, there is provided a separating / conveying section for separating and conveying a plurality of sheets sandwiched between the rotating member and the pressing member and conveyed one by one to the downstream side, and the stopping means is provided. The member is arranged between the rotating member and the separating / conveying unit.

An image reading apparatus of the present invention comprises an image reading unit for reading an image of an original and a paper feeding unit for feeding the original to the image reading unit, and the above-mentioned paper feeding unit is used for the paper feeding unit. Is characterized by.

The image forming apparatus of the present invention comprises an image forming section for forming an image on a sheet and a sheet feeding section for feeding the sheet to the image forming section, and the sheet feeding apparatus is used for the sheet feeding section. Is characterized by.

[0030]

According to the invention of claim 1, since the restraint member for restraining the sheets is provided, when a plurality of sheets are manually inserted, if the leading ends of the sheets hit the restraint member, they are completely positioned. You can set them in line.

According to the second aspect of the present invention, since the blocking member functions when the sheet is inserted, it does not become a resistance when the sheet is conveyed, and a feeding failure or the like does not occur.

According to the third aspect of the invention, if the restraining member is formed of a part of the guide member that guides the lower surface of the sheet, the position of the leading end can be adjusted very inexpensively.

In this case, the blocking member is fixed, and a gap is provided between the blocking member and the rotating member to allow the passage of the sheet during transportation, and the leading end is dammed by the blocking member during transportation. The sheet is lifted by the pressing member to the upper end of the blocking member.

According to a fourth aspect of the invention, the pressure releasing means is configured to mechanically interlock with the rotating member. That is, when the sheet is conveyed, the driving means generates a driving force in the direction in which the rotating member conveys the sheet to the downstream side, and therefore the pressing member is kept pressed against the rotating member at this time. On the other hand, when the conveyance of the sheet is completed, the rotating member is rotated in the direction opposite to the direction in which the sheet is conveyed to the downstream side, and the driving force separates the pressing member from the rotating member against the pressing force of the biasing means. , Form a predetermined gap.

According to a fifth aspect of the invention, the restraining member is movable to two positions, a restraining position for restraining the seat and a retracted position for permitting passage of the seat.

When the stopper member is fixed, it is necessary to provide a gap between the stopper member and the rotating member to allow the passage of the sheet, but if it is movable, the stopper member and the rotating member can be completely blocked without a gap. Therefore, the leading edge can be surely aligned even if the sheet is inserted at any position.

Further, the driving of the restraining member is also configured to mechanically interlock with the rotating member, as in the third aspect of the invention. That is, when the rotating member conveys the sheet to the downstream side, the stopping member is located at the retracted position.
On the other hand, when the conveyance of the sheet is completed, the rotating member is rotated in the direction opposite to the direction in which the sheet is conveyed to the downstream side, and the stopping member stands by at the stopping position in order to insert the next sheet.

According to the sixth aspect of the invention, the detection means for detecting the presence or absence of the sheet is provided.

After the completion of the sheet conveyance is detected by the detecting means, the driving means is caused to drive in the direction opposite to the direction in which the rotating member conveys the sheet to the downstream side, and the pressing releasing means is operated. Then, a gap is automatically formed between the rotating member and the pressing member.

According to the invention of claim 7, when the detecting means detects that the sheet is not conveyed normally due to the paper clogging, etc., the rotating member is removed after the sheet is completely removed. Drive is generated in the drive means in the direction opposite to the direction in which the sheet is conveyed to the downstream side, and the pressing release means is operated to form a gap between the rotating member and the pressing member.

When the separating / conveying unit is provided on the downstream side of the rotating member, a plurality of sheets are preliminarily conveyed to the separating / conveying unit by the rotating member with the leading ends of the sheets perfectly aligned. Be sure to separate one by one.

Further, even if a plurality of sheets are inserted extremely quickly, the sheets are blocked by the stopper, so that they can be prevented from reaching the separating / conveying section as in the conventional case.

If the above-mentioned paper feeding device is used for the paper feeding portion of the image reading device, a plurality of originals can be read smoothly.

Further, if the above-mentioned paper feeding device is used for the paper feeding portion of the image forming apparatus, a plurality of sheets can be fed smoothly.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. [Embodiment 1] Embodiment 1 of the present invention will be described with reference to FIGS.

FIG. 1 is a sectional view of a facsimile apparatus as an image reading apparatus embodying the present invention. That is, this facsimile apparatus has a paper feed section S for feeding the original P as a sheet, a transport section 9 for transporting the original P fed from the paper feed section S, and an original transported by the transport section 9. A reading unit 10 for reading the image of P and a paper discharge unit 11 for discharging the document P that has been read are provided.

The paper feed section S is a preliminary conveyance section S1 of the present invention for collectively conveying a plurality of manually loaded originals P.
And a plurality of documents P preliminarily transported from the preparatory transport unit S1.
And a separating and conveying section S2 for separating and conveying the sheets one by one.

In the preliminary conveying section S1, a preliminary conveying roller 3 as a rotating member for conveying a plurality of originals P, and a pressure contact plate 5 as a pressing member which can come into contact with and separate from the preliminary conveying roller 3 from below. And the pressure contact plate 5 to the pre-transport roller 3
A pressing spring 5 as an urging means for pressing with a predetermined pressure.
b and a release lever 6 as a pressure release means for releasing the pressure of the pressure contact plate 5 by the pressure spring 5b to form a gap between the pressure contact plate 5 and the preliminary conveyance roller 3 for inserting a plurality of originals P.
And a paper edge sensor 4 as a detecting means for detecting the presence / absence of the document P.

Then, the pressure contact plate 5 and the pre-transport roller 3
A stop member 12a for preventing the front ends of a plurality of documents P inserted in the gaps from being inserted beyond a predetermined amount is provided on the downstream side in the transport direction of the preliminary transport rollers 3 and in front of the separation / transport unit. .

The preliminary transport section is provided with a lower guide 12 and an upper guide 13 which are provided to face each other in the vertical direction so as to be opposed to each other in order to guide the document P, and the preliminary transport roller 3 is an upper guide. The pressure contact plate 5 is provided on the 13 side and on the lower guide 12 side.

The pressure contact plate 5 is a rotary shaft 5 located at the upstream end.
It is swingable around a as a fulcrum and has a release lever 6 and a pressing spring 5.
With b, it moves between two positions, a position in contact with the preliminary conveyance roller 3 and a position in contact with the lower guide 12.
The press plate 5 serves as a holding member that can hold the original P over its entire width.

In this embodiment, the stopping member 12a is fixed to the lower guide 12, and in particular, is integrally molded by a part of the lower guide 12 and serves to stop the leading edge of the original P to be inserted.

The paper edge sensor 4 is composed of a sensor lever 4a, one end of which projects into the passage between the lower guide 12 and the upper guide 13, and a sensor body 4b which is operated by the other end of the sensor lever 4a. When the leading edge of the document P hits the paper edge sensor lever 4a and pushes it in, the detecting portion of the sensor body 4b is activated.

The separating / conveying section S2 is composed of a separating roller 1 and a separating piece 2 that abuts on the separating roller 1, and only one of the plurality of overlapping originals P conveyed from the preliminary conveying section. It is separated and sent to the downstream side. The separating piece 2 is composed of an elastic member so as to stop the originals other than one sheet which come into contact with the separating roller 1 and separate. Further, the separating piece 2 is biased by the spring force of the separating spring 7 so as to be pressed against the separating roller 1.

From the separation / conveyance section of the sheet feeding section, the conveyance section 9 is
An intermediate conveyance roller pair 9a, 9b is provided to convey the originals P conveyed one by one to the rear. Further, a trailing edge sensor 8 that detects that the document P has passed is provided on the downstream side of the pair of conveying rollers 9a and 9b and before the reading unit. The trailing edge sensor 8 is composed of a sensor lever 8a that is swung by the passing document P and a sensor body 8b that is activated by the swing of the sensor lever 8a. When the leading edge of the document P hits the trailing edge sensor lever 8a and pushes it in, the trailing edge sensor 8b is actuated, and the trailing edge of the document P is trailing edge sensor lever 8a.
The operation of the rear end sensor 8b is released when the vehicle passes.

The document reading section 10 is provided with a contact sensor 10a for reading an image of a document P passing therethrough.

Further, in the paper discharge section 11, a pair of paper discharge rollers 11 for discharging the document P read by the reading section 10 to the outside of the apparatus.
a and 11b are provided.

FIG. 2 is a view of the rotation driving portion of the paper feeding section of FIG. 1 as seen from below.

In FIG. 2, reference numeral 15 is a lever rotation shaft that serves as a rotation center of the release levers 6 and 6, and 16 is a lever rotation shaft 15.
Reference numeral 17 denotes a torque limiter coupled to the input gear, and 17 denotes an input gear that transmits the rotational drive from a reading motor (not shown), which is a drive source, to the separation roller 1, the pre-transport roller 3, and the torque limiter 16. The pre-conveyance roller 3 has a lever rotation shaft 15
It is rotatably supported by.

3 to 6 show the operating state of the sheet feeding device. FIG. 4 is a standby state, FIGS. 3 and 5 are a state in which a document P is inserted, and FIG. Represents up to.

FIGS. 1 and 4 show the paper feeding device in the standby state, and the paper edge sensor 4 including the sensor lever 4a and the sensor body 4b recognizes "no original".

At this time, since the release lever 6 pushes the pressure contact plate 5 downward, the preliminary conveying roller 3 and the pressure contact plate 5 are separated from each other, and a gap is formed therebetween. Here, as shown in FIG. 2, since the release lever 6 is outside the passage area of the document P, it does not hinder the insertion of the document P.

Next, the operation when the document P is set will be described. When a plurality of (or one) originals P are inserted into the gap between the pre-transport roller 3 and the pressure plate 5, the leading edge of the original P lowers by its own weight, and the leading edge of the original P as shown in FIGS. 3 and 5. The raised blocking member 12a abuts against the overloading of the document P. Further, the leading end of the document P has the stopping member 12a.
Immediately before contact with the sheet edge sensor lever 4a,
The sheet edge sensor 4b detects that "the document is present" by hitting the tip of the sheet.

A few seconds after the detection section of the paper edge sensor 4b detects "there is a document" (after a time sufficient for the leading edge of the document P to hit the stopping member 12a), it is a drive source (not shown). Drive is transmitted from the reading motor, and each roller rotates in the direction of the broken line arrow in FIG. At this time, since the release lever 6 is also connected to the reading motor, the release lever 6 also moves in the direction of the broken arrow as the rollers rotate. here,
When the release lever 6 is rotationally driven to a position where the pressure contact plate 5 is opened and the pressure contact plate 5 presses the preliminary conveyance roller 3, the release lever 6 hits a stopper (not shown) and is prevented from rotating. Since the lever rotation shaft 15 of the release lever 6 is coupled to the torque limiter 16, the torque limiter 1
Only the gear No. 6 runs idle, the drive is not transmitted to the lever rotation shaft 15, and the release lever 6 is held at the position shown in FIG.

The pressure contact plate 5, which has been pushed downward by the rotation of the release lever 6, is rotated upward by the rotation of the release lever 6. Then, the document P stacked on the pressure contact plate 5 is also lifted and released from the stop of the stop member 12 as shown in FIG. Further, the lifted document P is pressed against the preliminary conveyance roller 3 and is conveyed downstream by the preliminary conveyance roller 3 which is rotationally driven.

The leading edge of the original P conveyed by the preliminary conveying roller 3 hits the contact portion between the separating roller 1 and the separating piece 2 and the uppermost one original is dragged by the rotating separating roller 1, and the remaining originals are separated. The sheet 2 is blocked and the sheets are fed one by one in the next process.

The originals P fed one by one are further conveyed by the intermediate conveying roller pair 9, and when the leading edge of the original P hits the trailing edge sensor lever 8a and pushes it in, the leading edge position of the trailing edge sensor 8b is reached. Is detected. The contact sensor 10 starts reading according to the position of the leading edge of the document P, and ends the reading at the timing when the trailing edge of the document P passes through the trailing edge sensor lever 8a. When the reading by the contact sensor 10 is completed, the document P is discharged to the outside of the apparatus by the discharge roller 11. The number of steps for rotating the paper discharge roller 11 is managed by the trailing edge sensor 8, and the number of steps required to eject the original P from the apparatus after the trailing edge of the original P passes the sensor lever 8a, The motor is controlled to rotate.

Although the standby state is returned after the discharge of the document P is completed, the pressure contact plate 5 is still in pressure contact with the preliminary conveyance roller 3 and it is difficult to set the next document in this state. Therefore,
After the document P is discharged, the reading motor, which is the drive source, is rotated in the opposite direction, and each roller and the release lever 6 are rotated in the direction of the solid line arrow in FIG. When the release lever 6 rotates in the direction of the solid line arrow, the release lever 6 pushes down the pressure contact plate 5,
A space is formed between the pre-conveyance roller 3 and the pressure contact plate 5, and FIG.
Return to the standby state.

As described above, by providing the restraining member 12a, the setting and separation / conveyance of the document P can be ensured at a low cost, and the feeding performance can be improved. [Embodiment 2] The reliability is remarkably improved by providing a stopper plate that moves in conjunction with the vertical movement of the pressure contact plate, instead of the fixed stopper member 12a of the first embodiment.

7 to 9 are detailed explanatory diagrams showing the operating state of the sheet feeding device of the reading section of the facsimile apparatus. In these figures, the same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted. Only the different points will be described below.

In this embodiment, the press-contact plate 105 is provided with a push-down portion 105c by extending the tip thereof.

Further, the stopping member 121 has a rotation center 121a.
Is rotatably held about the center of the arrow and is biased by a biasing member (not shown) so as to rotate in the direction of the arrow in FIG. Reference numeral 121b is a pin forming a part of the stopper member 121, and is a push-down portion 105 at the tip of the press-contact plate 105.
When pushed down by c, the stopping member 121 is configured to stand up against the biasing member as shown in FIG.

The operation state of the second embodiment is shown in FIG. 2 and FIGS.
Will be explained.

FIG. 7 is a diagram showing the paper feeding device in a standby state, and the paper edge sensor 4 recognizes "no original".

At this time, since the release lever 6 pushes the pressing plate 105 downward, the pre-conveying roller 3 and the pressing plate 1 are pushed.
05 is separated and there is a space between them. Here, since the release lever 6 is outside the passage area of the document P, it does not hinder the insertion of the document P. In addition, the stop member 121,
Since the pin 121b is pushed down by the push-down portion 105c of the press contact plate 105, the pin 121b rotates about the rotation center 121a and rises from the lower guide 12.

Next, the operation when the document P is set will be described. When a plurality of (or one) originals P are inserted into the space between the pre-transport roller 3 and the pressure plate 105, the leading edge of the original P is lowered by its own weight and rises with the leading edge of the original P as shown in FIG. The stopping member 121 that is in contact therewith prevents the document P from being excessively inserted. In addition, the leading end of the document P is the stopper member 12.
Immediately before coming into contact with 1, the sensor lever 4a abuts against the leading edge of the document P and moves, and the detection portion of the sensor body 104b detects "document present".

A few seconds after the paper edge sensor 104 detects "there is a document" (after a time sufficient for the leading edge of the document P to hit the stopping member 121), a reading motor (not shown) serving as a drive source is used. The drive is transmitted and each roller rotates in the direction of the broken arrow in FIG. At this time, the release lever 6
Is also connected to the reading motor, it moves in the direction of the broken line arrow as the rollers rotate. Here, when the release lever 6 is driven to rotate to a position where the pressure contact plate 105 is opened and the pressure contact plate 105 presses the preliminary transport roller 3, the release lever 6 hits a stopper (not shown) and is prevented from rotating. Since the lever rotation shaft 15 of the release lever 6 is coupled to the torque limiter 16, the torque limiter 1
Only the gear No. 6 runs idle, the drive is not transmitted to the lever rotation shaft 15, and the release lever 6 is held at the position shown in FIG.

The pressing plate 105, which has been pushed down by the rotation of the release lever 6, is rotated upward by the rotation of the release lever 6. Then, the pin 12 that has been pushed down by the pushing-down portion 105c of the press-contact plate 105.
The force applied to 1b is released, and the stopping member 121 falls down following the lower guide 12 (FIG. 9). At this time, the pressure contact plate 10
The document P stacked on the sheet 5 is lifted, pressed against the pre-conveying roller 103 as shown in FIG. 9, and conveyed downstream by the pre-conveying roller 3 which is rotationally driven.

The operation of other strokes and the operation of returning to the standby state are the same as in the first embodiment.

As described above, since the original P can be surely stopped by the stop member 121 which is the movable member, it is possible to deal with the original P having a scattered tip.
The performance can be remarkably improved. [Third Embodiment] In the first and second embodiments, it is described that the paper feeding device returns to the standby state after the discharge operation of the document P is completed, but here, the document P is not discharged successfully. The operation of time will be described.

In the state of FIG. 3, when the original P is pulled out, the original P does not pass the trailing edge sensor lever 8a. Therefore, in the description of the first embodiment, the reverse rotation operation of the reading motor is always performed. There will be no. When the document P is pulled out, the paper edge sensor 4 changes from “document present” to “no document”, and the trailing edge sensor 8 remains “no document”. When such a state is reached, the reverse rotation operation of the reading motor is immediately performed, and the pressure contact plate 5 is retracted from the preliminary conveyance roller 3.

When the original P reaches the trailing edge sensor 8 and is pulled out, the reverse operation of the reading motor is performed several seconds after the trailing edge sensor 8 is cut off as in the case of normal termination. The pressure contact plate 5 is retracted from the preliminary conveyance roller 3.

As described above, since the pressure contact plate 5 is retracted from 0N / OFF of the paper edge sensor 5 and the trailing edge sensor 8 as a starting point, it is possible to adapt to the abnormal operation.

In the above embodiment, the case where the present invention is applied to the document feeding section of the image reading apparatus such as a facsimile has been described, but the present invention is not limited to this and an automatic document feeding apparatus such as a copying machine or an image reader. Also applicable to image readers.

Further, the present invention can be applied to a paper feeding unit for feeding an image forming sheet to an image forming unit of an image forming apparatus such as a copying machine or a printer.

[0086]

As described above, according to the present invention,
Since the stop member for stopping the leading edge of the sheet is provided, the leading edge of the sheet can be easily positioned.

When the restraining member is positioned at the restraining position only when the sheet is inserted, stable feeding can be performed without adding resistance to the sheet when the sheet is fed, and a highly reliable apparatus can be provided.

When the restraining member is constituted by a part of the guide member for guiding the lower surface of the sheet, it becomes possible to position the leading end very inexpensively.

When the pressure releasing means is mechanically interlocked with the rotating member, the sheet can be easily loaded at low cost without adding an electric part for exclusive use of releasing the pressure.

When the stopper member is movable, it is not necessary to provide a gap for allowing the passage of the sheet between the stopper member and the rotating member as in the case where the stopper member is fixed, and there is no gap between the stopper member and the rotating member. Since it can be shut off at any position, it is possible to reliably align the leading edge regardless of the position of the sheet.

Also, the driving of the restraining member can be inexpensively constructed by mechanically interlocking with the rotating member.

After the detection means detects that the conveyance of the sheet is completed, the drive means is caused to drive in the direction opposite to the direction in which the rotary member conveys the sheet to the downstream side, and the rotary member and the pressing member are automatically driven. If a gap is formed between the two, when the operation of the paper feeding device ends normally,
The seat can always be returned to a state where it can be easily loaded.

When the detecting means detects that the sheet is not conveyed normally, the rotating means causes the driving means to drive in the direction opposite to the direction in which the rotating member conveys the sheet to the downstream side, and automatically. When a gap is formed between the rotating member and the pressing member, even if the operation of the sheet feeding device is not normally completed, it becomes possible to always return the sheet to a state in which it is easy to load. .

Further, when the separating / conveying unit is provided on the downstream side of the rotating member, the rotating member preliminarily conveys to the separating / conveying unit in a state where the leading ends of the sheets are perfectly aligned. Can be reliably separated one by one.

Furthermore, even if a plurality of sheets are inserted extremely quickly, the sheets are blocked by the stop portion, so that they cannot reach the separating / conveying portion as in the conventional case.

On the other hand, if the paper feeding device is used as the paper feeding portion of the image reading device, a plurality of originals can be read smoothly.

If the above-mentioned paper feeding device is used for the paper feeding portion of the image forming apparatus, the plural sheets can be fed smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view of a document standby state according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the drive system of the sheet feeding unit according to the first embodiment of the present invention, as seen from below.

FIG. 3 is a sectional view of the first embodiment of the present invention during a sheet feeding operation.

FIG. 4 is a detailed explanatory diagram of a standby state of the sheet feeding unit according to the first embodiment of this invention.

FIG. 5 is a detailed explanatory diagram of a document loading state of the sheet feeding unit according to the first embodiment of the present invention.

FIG. 6 is a detailed explanatory diagram of a document feeding state of a sheet feeding unit according to the first exemplary embodiment of the present invention.

FIG. 7 is a detailed explanatory diagram illustrating a standby state of the sheet feeding unit according to the second embodiment of this invention.

FIG. 8 is a detailed explanatory diagram of a document loading state of a paper feeding unit according to the second embodiment of the present invention.

FIG. 9 is a detailed explanatory diagram of a document feeding state of a sheet feeding unit according to the second embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a standby state of a conventional sheet feeding device.

FIG. 11 is a cross-sectional view of a conventional water absorbing device during a paper feeding operation.

[Explanation of symbols]

 1 Separation Roller 2 Separation Piece 3 Preliminary Conveying Roller 4 Paper Edge Sensor (Detecting Means) 5,105 Pressing Plate 5b, 105b Pressing Spring 6 Release Lever 8 Rear Edge Sensor 12a, 121 Stopping Member 30 Paper Feed Port

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H04N 1/00 108 H04N 1/00 108 (72) Inventor Shigeyuki Sugiyama 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 in Canon Inc. (72) Inventor Atsushi Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Noriyuki Aoki No. 3-30-2 Shimomaruko, Ota-ku, Tokyo Canono (72) Inventor Akio Okubo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (10)

[Claims] 1. A rotating member that conveys a sheet, a pressing member that is provided so as to come in contact with and away from the rotating member, and the pressing member and the rotating member are separated from each other, and a gap for inserting the sheet is formed therebetween. A sheet feeding device that includes a pressure releasing unit and a driving unit that rotationally drives the rotating member, and that conveys a sheet inserted in a gap between the pressing member and the rotating member by sandwiching the sheet between the rotating member and the pressing member. In the sheet feeding device, the stopping member is provided on the downstream side of the rotating member in the conveying direction so as to prevent the front end of the sheet inserted into the gap between the pressing member and the rotating member from being inserted by a certain amount or more. . 2. The stopping member is in a position to stop the leading edge of the sheet when the pressing member and the rotating member are separated from each other,
The sheet feeding device according to claim 1, wherein when the sheet is conveyed by the pressing member and the rotating member, the sheet is in a position where the leading end of the sheet is not stopped. 3. The sheet feeding device according to claim 1, wherein the restraint member is a part of a guide member that guides a lower surface of the sheet. 4. The pressing releasing means maintains the pressing member in a pressed state against the rotating member when the driving means generates a driving force in a direction in which the rotating member conveys the sheet to the downstream side, When the driving means generates a driving force for rotating the rotating member in the direction opposite to the direction in which the sheet is conveyed to the downstream side, the pressing of the pressing member with respect to the rotating member is released and the pressing member and the rotating member are The sheet feeding device according to claim 1, wherein a predetermined gap is formed therebetween. 5. A driving force in a direction in which a restraining member is movable to two positions, a restraining position for restraining a sheet and a retracted position for permitting passage of the sheet, and the rotating member conveys the sheet downstream. When the driving means is generated, the stopping member is retracted from the stopping position to the retracted position, and the driving means generates a driving force in a direction opposite to the direction in which the rotating member conveys the sheet to the downstream side. 5. The paper feeding device according to claim 4, wherein the stopping member is configured to stand by at the stopping position when the above-mentioned situation occurs. 6. A drive unit in a direction opposite to a direction in which the rotating member conveys the sheet downstream after providing a detection unit for detecting the presence or absence of the sheet and detecting that the conveyance of the sheet is completed by the detection unit. Is generated in the drive means,
The sheet feeding device according to claim 4, wherein a gap is formed between the rotating member and the pressing member by operating the pressing releasing means. 7. When the detection means detects that the sheet is not conveyed normally, the drive means is caused to drive in a direction opposite to the direction in which the rotating member conveys the sheet to the downstream side. 7. The paper feeding device according to claim 6, wherein a gap is formed between the rotating member and the pressing member by operating the pressing releasing means. 8. A separating / conveying unit is provided on the downstream side of the rotating member in the conveying direction, and separates and conveys a plurality of sheets sandwiched between the rotating member and the pressing member and conveyed to the downstream side one by one, 8. The blocking member is arranged between the rotating member and the separation / conveyance unit, according to any one of claims 1 to 7.
The paper feeding device according to the item. 9. An image reading unit for reading an image of an original document, and a paper feeding unit for feeding the original document to the image reading unit, wherein the paper feeding unit is according to any one of claims 1 to 8. An image reading apparatus using a sheet feeding device. 10. An image forming unit for forming an image on a sheet,
An image forming apparatus comprising: a sheet feeding unit that feeds a sheet to the image forming unit, wherein the sheet feeding device according to claim 1 is used as the sheet feeding unit.