JP2001220026A - Bunched sheet separating and feeding device, automatically document carrying device, image forming device and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the impact noise of a feeding member when lifted down on bunched sheets, if thinner, by reducing the substantial lift-down starting height of the feeding member such as a pickup roller when lifted down to the bunched sheets P. SOLUTION: A lifting means 140 for lifting the feeding member 20 up and down on a placement board 10 limits the lift-down of the feeding member 20 on its way when lifting the feeding member 20 down from a lift-up position h1 and executes lift-down limiting action for reducing a lift-down speed after limitation.

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 a sheet bundle, and a document conveying apparatus, an image forming apparatus and an image reading apparatus using the same. The present invention relates to a mechanism and an apparatus suitable for setting and transporting the sheet by friction separation.

[0002]

2. Description of the Related Art When a sheet bundle of cut sheets or the like is separated one by one and conveyed to a predetermined position, a friction conveying roller is pressed against one side of the sheet bundle to move the one side sheet to the separation position side. 2. Description of the Related Art Separate feeding devices that perform feeding, that is, perform a so-called calling operation (pickup operation), are frequently used.

Particularly, in an automatic document feeder provided in an image forming apparatus such as a copying machine or a facsimile machine, image sheets are separated one by one from a bundle of documents (documents) set on a document table. The sheet is conveyed to a reading section (scanner section). In this case, this type of mechanism is widely used as a separation sheet feeding mechanism.

In such a sheet bundle separating and feeding apparatus, a document is set with a document image surface facing up, in order to reduce fouling of the document and a rule of facsimile transmission of transmitting the pages in order. The form of feeding pages sequentially has become mainstream and is becoming popular.

[0005] In this case, the separating and feeding apparatus usually has a separating section for feeding the original sheet in the transport direction while separating the original sheet, and a call roller for feeding the original sheet to the separating section.
When performing feeding with the original image side up, the call roller is separated from the original image surface in accordance with the timing of transporting the separated uppermost original sheet to the original reading position, and then the call roller is moved to the next original sheet. To the original document image surface.

In this separating and feeding apparatus, a roller elevating system in which a call roller is lifted (retracted) so as to be separated from a document image surface and lowered so as to abut on the document image surface;
There is a mounting table elevating method in which the original mounting table itself is raised and lowered.

In the case of the former method of raising and lowering the document table, it takes time to raise and lower the document table. Particularly when the document needs to be raised or lowered greatly at the time of setting the document, separation and feeding of the document from a start command such as copying are performed. It takes quite a while to get started. In particular, the contact pressure of the call roller on the original sheet is preferably reduced to some extent in order to reduce the contamination of the original, but it is not possible to obtain such contact pressure while moving the original placing table and the thick original sheet bundle up and down. It is inevitable to set a contact pressure range that is not easy and easily causes document contamination.

On the other hand, in the case of the latter roller raising / lowering method, the original is driven by its own weight or its biasing force of the degree that it is mainly applied (to the extent that it is slightly downwardly biased by a torsion spring having a small spring constant). By pressing against a sheet, a stable pressing force suitable for frictional conveyance can be applied regardless of the thickness of the original sheet bundle. In addition, since there is no need to raise and lower the original mounting table, which is a large component, there is an advantage that the configuration can be simplified. Further, there has been proposed a device in which the calling roller can be rotated and driven by the same drive source as the separating means, the number of components is reduced, and the configuration is further simplified (see JP-A-11-143139).

[0009]

However, in such an apparatus for separating and feeding a sheet bundle, an automatic document feeder, an image forming apparatus and an image reading apparatus using the same, a call roller (feeding member) is provided. If you try to process a larger number of original sheet bundles in
It is necessary to retract the call roller to a position higher than the upper surface of the original sheet bundle having the maximum stacking thickness. for that reason,
When the retracting height of the call roller on the document sheet bundle is increased, an unpleasant hitting sound or an impulsive sound is generated when the call roller descends or falls.

In particular, when the stack of original sheets is thin, when the call rollers fall from a high retreat position and come into contact with the upper surface of the document, the call rollers collide with a guide plate constituting the bottom surface of the document table. The impact sound at the time of the collision gave the user discomfort.

This problem has been evident since the hitting sound and the impact sound described above are periodically repeated when the calling roller repeatedly descends and rises when the document is separated.

On the other hand, for example, it is conceivable to reduce the impact sound by increasing the rigidity of the bottom surface of the document table or by arranging some cushioning material below the call roller. In a separation feeding device that is downsized and simplifies the configuration by obtaining the rotational driving force from the separation means in a lifting and lowering method, it is not advisable to adopt such a reinforcing structure or add expensive parts. is not.

In view of the above, the present invention reduces the height of a substantial drop starting point when a feeding member such as a pickup roller descends toward a sheet bundle, thereby making it possible to feed from a single sheet to a thick sheet bundle. It is intended to reduce the impact sound and the like when the sheet feeding member falls into the sheet bundle even if the sheet bundle is thin, while enabling the sheet feeding. It is an object of the present invention to provide a separation feeding device and a document conveying device that reduce noise, and an image forming apparatus and an image reading device that use the same for reading a document.

[0014]

According to a first aspect of the present invention, there is provided an image forming apparatus, comprising: a mounting table on which a sheet bundle is mounted; and a predetermined position above the sheet bundle mounted on the mounting table. A feeding member that comes into contact with the urging force to call the upper sheet of the sheet bundle to the separation position, and a separation member that separates the uppermost sheet of the sheets called to the separation position by the feeding member from the lower sheet. Means, and raises the feeding member so as to be separated from the uppermost sheet, holds the feeding member at the raised position, and releases the holding to allow the feeding member to be lowered by the urging force, so that the feeding member is positioned above the sheet bundle. An elevating unit that raises and lowers the feeding member by bringing the feeding member into contact with the sheet bundle. Reduce the lowering speed of the feeding member It is characterized in that it is capable of executing the descending restriction operation.

In this separation and feeding device for a sheet bundle, when the raising and lowering of the feeding member is stopped at the ascending position which is the upper stop position in the ascending and descending range of the feeding member, the sheet can be fed even if the sheet bundle is thick. Becomes Further, when the feeding member descends from its rising position, the lowering of the feeding member is restricted in the middle of the lowering, and the lowering speed after the restriction is reduced, so that the substantial drop starting position of the feeding member is lowered. As a result, the impact noise can be reduced.

According to a second aspect of the present invention, in the apparatus for separating and feeding a sheet bundle according to the first aspect, the lowering operation of the raising and lowering means is performed below the raising position while allowing the lowering of the feeding member. The operation is an operation of decreasing the descending speed of the feeding member. In this configuration, when the feeding member descends to the predetermined height position below the rising position, the descending speed is reduced, so that the vicinity of the predetermined height is fed without fine control of the retraction height. The impact sound can be reduced as the substantial drop start position of the member.

According to a third aspect of the present invention, in the apparatus for separating and feeding a sheet bundle according to the first aspect, the lowering operation of the raising and lowering means is performed by temporarily lowering the feeding member below the raising position. The operation is a stopping operation.
In this configuration, when the feeding member descends to the predetermined height position below the rising position, the lowering is temporarily stopped, so that the vicinity of the predetermined height is fed without fine control of the retraction height. As a substantial drop starting position of the member,
Impact noise can be reduced.

According to a fourth aspect of the present invention, in the apparatus for separating and feeding a sheet bundle according to the third aspect, the elevating means moves at a position higher than a position where the feeding member contacts the sheet bundle on the mounting table. The feeding member is dropped from a lower position of any of the rising position and the intermediate stop position for temporarily stopping the lowering of the feeding member.
In this configuration, the drop starting height of the feeding member is higher than the position where the feeding member comes into contact with the sheet bundle on the mounting table, and the rising position or the intermediate stop position for temporarily stopping the lowering of the feeding member is selected. If the height at which the feeding member is retracted is higher than the contact position with the sheet bundle, the height can be set freely within the height range from the intermediate stop position to the elevation position. There is no need to control the evacuation height in detail according to the height of the bundle.

According to a fifth aspect of the present invention, there is provided an image forming apparatus, comprising: a mounting table on which a sheet bundle is mounted; and an upper portion of the sheet bundle mounted on the mounting table, which is brought into contact with the upper portion of the sheet bundle by a predetermined urging force. To the separation position, separating means for separating the uppermost sheet of the sheets called to the separation position from the lower sheet by the feeding member, and a driving cam for driving the feeding member up and down And a drive transmission member for transmitting a drive force from the drive cam to the feed member,
The feeding member is lifted so as to be separated from the uppermost sheet and held at the raised position, and the holding is released to allow the feeding member to descend by the urging force and to contact the upper portion of the sheet bundle. Lifting means for raising and lowering the feeding member, the separation and feeding device for a sheet bundle, wherein the lifting means makes a part of a cam surface of the driving cam abut on the drive transmission member, and A feed member capable of holding the feed member at the raised position, releasing a part of a cam surface of the drive cam from the drive transmission member to release the holding of the feed member at the raised position; Limiting the lowering of the feeding member via the drive transmission member at the rest of the cam surface during the lowering,
The lowering speed of the feeding member after the restriction is reduced.

In this configuration, when the feeding member is lowered from its raised position, the lowering of the feeding member during the lowering is limited,
Since the lowering speed after the restriction is reduced, the dropping position of the feeding member is substantially reduced, and the impact noise can be reduced. In addition, since the feeding member is driven to move up and down by the driving cam, it is possible to perform a quick ascending and descending drive, and furthermore, it is possible to provide a simple elevating means in which the retracting speed and the descending speed can be easily set according to the cam shape.

According to a sixth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the fifth aspect, when the driving cam releases the holding of the feeding member at the raised position, the driving cam rotates. Is characterized by a constant speed. In this configuration, since the rotation of the drive cam is at a constant speed, complicated control is not required.

According to a seventh aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the fifth or sixth aspect, the driving cam has a first cam surface of a maximum lift and an intermediate lift smaller than the maximum lift. A second cam surface, and a third cam surface having a minimum lift smaller than the intermediate lift, wherein the elevating means rotates the drive cam forward and reverse to form the second cam surface and the third cam surface. Are alternately opposed to the drive transmission member, and the feeding member can be moved up and down within a predetermined range below the ascending position.
In this configuration, the feeding member can be moved up and down in a predetermined range below the ascending position, so that when the number of stacked sheets in the sheet bundle is small, the retracting height is set to an intermediate retracting height to further reduce impact noise. Can be done.

According to an eighth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the fifth or sixth aspect, the driving cam has a first cam surface of a maximum lift and an intermediate lift smaller than the maximum lift. A first cam position having a second cam surface and a third cam surface having a minimum lift smaller than the intermediate lift, and detecting that the first cam surface of the drive cam has contacted the drive transmission member; Detecting means and a second drive cam.
And a second cam position detecting means for detecting that the cam surface has come into contact with the drive transmission member. With this configuration, it is possible to switch the evacuation operation and determine the necessity of the evacuation operation by using a simple detection unit that detects the rotational angle position of the detected member.

According to a ninth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to any one of the first to eighth aspects, the weight of the feeding member acts as the urging force. It is.

[0025] The invention according to claim 10 is the invention according to claims 1 to 6,
The sheet bundle separating and feeding device according to any one of 8 and 9, wherein the sheet feeding member is retracted to the raised position regardless of the height of the sheet bundle on the mounting table. . In this configuration, since the height at the time of evacuation is not variably controlled, the control is simplified.

According to an eleventh aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the tenth aspect, the drive cam has a first cam surface of a maximum lift and an intermediate lift smaller than the maximum lift. A cam surface and a third cam surface having a minimum lift smaller than the intermediate lift, wherein the elevating means rotates the drive cam only in one direction, and causes the first cam surface and the second cam surface to rotate. A cam surface and the third cam surface are sequentially opposed to the drive transmission member. In this configuration, it is sufficient to simply rotate the driving cam in one direction, so that the elevation control of the feeding member is simplified.

According to a twelfth aspect of the present invention, in the apparatus for separating and feeding a sheet bundle according to any one of the first to ninth aspects, the lifting / lowering means is provided when there is no sheet on the table.
The sheet feeding member is retracted to the raised position, and when a sheet is placed on the mounting table, at least the first one
In the rotation, the feeding member is lowered from the raised position to a contact position with the sheet bundle.
With this configuration, when the sheet bundle is mounted on the mounting table, the feeding member always retreats at the raised position,
Can handle thick originals. In addition, since the operation of lowering the feeding member from the raised position to the sheet bundle is performed at least once at the first time, the retracting height of the feeding member can be reduced if the sheet bundle is thin.

According to a thirteenth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to any one of the first to ninth or twelfth aspects, the elevating means moves according to the height of the sheet bundle on the mounting table. Performing one of a first retracting operation of retracting the feeding member to the raised position and a second retracting operation of retracting the feeding member to an intermediate stop position below the raised position. The retracting height of the feeding member from the uppermost sheet is adjusted to a certain height or less. In this configuration, by switching between the first evacuating operation and the second evacuating operation to keep the evacuating height low, noise can be further reduced.

According to a fourteenth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to any one of the first to eighth aspects, the weight of the feeding member acts as the urging force. It is. Here, the state in which the own weight acts as the above-mentioned urging force means that the urging force due to the own weight of the feeding member and its supporting portion is reduced by other auxiliary urging force (for example, the lowering by an elastic member such as a torsion spring having a small spring constant). A substantially constant biasing force in the direction). In this configuration, since the contact pressure of the feeding member to the sheet bundle is about its own weight, a stable contact pressure suitable for frictional feeding can be obtained regardless of the thickness of the sheet bundle.

According to a fifteenth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the thirteenth aspect, an intermediate retreat height for detecting that the feeding member has reached an intermediate retreat position lower than the raised position. Detecting means, the elevating means based on the detection information of the intermediate retreat height detecting means,
And switching between the second save operation and the second save operation. With this configuration, when the actual contact height of the feeding member to the sheet bundle reaches a predetermined height, this is detected by the intermediate retreat height detecting means. At a preferable timing, the retracting height of the feeding member can be switched.

According to a sixteenth aspect of the present invention, in the sheet bundle separating and feeding apparatus according to the thirteenth aspect, sheet height detecting means for detecting the height of the sheet bundle on the mounting table is provided.
The elevating means switches between the first retreat operation and the second retreat operation based on the detection information of the sheet height detecting means. With this configuration, if the number of stacked sheets is input by the sheet height input unit to be small or large, the retreat height of the feeding member is switched, so that the retreat height can be reliably switched when necessary. . The sheet height detecting means is not limited to directly detecting the height of the sheet bundle on the mounting table, but by detecting the position of a feeding member or other members,
The height of the sheet bundle in the vicinity of the feeding member may be indirectly detected. In addition, it is possible to perform fine vertical drive control of the feeding member according to the sheet height. By raising and lowering the feeding member, for example, the contact time between the feeding member and the sheet can be set to a more preferable range. It can also be controlled.

According to a seventeenth aspect of the present invention, there is provided an automatic document feeder comprising the sheet bundle separating and feeding device according to any one of the first to fourteenth aspects. In this automatic document feeder, if the raising and lowering of the feeding member is stopped at the ascending position, which is the upper stop position of the ascending and descending range of the feeding member, the thick sheet bundle can be fed. Further, it is possible to reduce the impact noise when the feed roller is lowered from its raised position.

[0033] The image forming apparatus according to claim 18 is:
A sheet bundle separating and feeding device according to any one of claims 1 to 14 is provided. In this image forming apparatus, when the ascending and descending of the feeding member is stopped at the ascending position which is the upper stop position of the ascending and descending range of the feeding member, the sheet can be fed even if the sheet bundle is a thick copy original or a transmission original. Becomes Further, it is possible to reduce the impact noise when the feed roller is lowered from its raised position.

An image reading apparatus according to a nineteenth aspect of the present invention
A sheet bundle separating and feeding device according to any one of claims 1 to 14 is provided. In this image reading apparatus, when the ascending and descending of the feeding member is stopped at the ascending position which is the upper stop position of the ascending and descending range of the feeding member, the sheet can be fed even if the sheet bundle is a thick document to be read. Further, it is possible to reduce the impact noise when the feed roller is lowered from its raised position.

[0035]

Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]

FIGS. 1 to 12 show a sheet bundle separating and feeding apparatus according to a first embodiment of the present invention, an automatic document feeder using the same, and an image forming apparatus equipped with the automatic document feeder. FIG. The image forming apparatus main body 1000 shown in FIG. 1 operates independently as a copier and a facsimile machine, and can be used as a scanner (image reading device) and a printer in a state where it is connected to an external computer. An automatic document feeder (hereinafter, referred to as ADF) 200 is provided on the image forming apparatus main body 1000.

As a reading method of the image forming apparatus provided with the ADF 200, there are a scanning method in which an original is stopped on a contact glass and a scanner section is scanned, and a reading method in which the scanner section is stopped and an original is moved to read. Although a sheet-through method is known, in the present embodiment, a sheet-through method is used. That is, the image forming apparatus main body 1000 is configured to read an image from the ADF 200 while transporting the document from the ADF 200 to a fixed reading unit (image reading unit) at a predetermined speed. Since such a basic configuration of the image forming apparatus main body 1000 is known, the following description mainly focuses on the ADF 200 in detail.

The ADF 200 includes a document setting section 1, a separation sheet feeding section 2, a registration section 3, a reversing section 4, a first reading and conveying section 5,
(Conveying means), a second reading / conveying unit 6, a paper discharging unit 7, a reversing conveying unit 8, a stacking unit 9, and a driving unit for driving these conveying operations (a calling motor 101, a paper feeding motor 102, The reading motor 103, the reversing motor 104, the reversing switching solenoid 105, etc.), and a controller 100 (shown in FIG. 2) for controlling a series of document conveyance operations by these components.

The document setting section 1 includes a document setting table 1
0, side guide 11, first document length sensor 12, second document
A document length sensor 14, a document stopper 25, and the like are provided to set a document sheet bundle P of a single-sided or double-sided document. The document set table 10 is configured to be open and rotatable upward about a rotation fulcrum 95, thereby facilitating removal of stacked documents. Each of the first original length sensor 12 and the second original length sensor 14 is a reflective sensor or an actuator that can detect even one original.
Of the same document size.

The separation paper feed unit 2 includes a pickup roller 2
0, paper feed belt 23, document stopper 25, separation roller 2
6. The originals are separated and fed one by one from the original sheet bundle P set on the original set table 10. The states of the pickup roller 20 and the document stopper 25 are detected by a home position sensor (for example, constituted by an optical reflection sensor) 19.

The registration section 3 is composed of an abutment sensor 29, a registration roller 30, a width size sensor group 32, etc., and performs an operation of firstly abutting and aligning a fed document, and drawing out the aligned document. To carry out the operation.

The reversing section 4 comprises a reading and conveying roller 43, a pressure roller 35, a registration sensor 40, and the like. The reversing section 4 reverses the document conveyed to the reading position and conveys the image surface toward the reading side (downward). I do.

The first reading and conveying unit 5 includes the reading and conveying roller 4
3, the original being read and conveyed includes a contact roller 54, a white background plate 51, a contact glass 54, and a white background plate 51 arranged at a predetermined interval on the upper surface of the contact glass. Pass between. Then, the surface image of the original is read by the contact glass 54 by a reading system (not shown) in the image forming apparatus main body 1000.
The image is read from the bottom of the
, And is stored in a memory device (image memory) (not shown).

In order to make the transport gap in the first reading transport section 5 as narrow as possible and to minimize the degree of freedom of the original, a flexible guide member is extended from the inner surface of the reading entrance guide 42 toward the white background plate 51. It is configured to fill the gap. Further, the white background plate 51 disposed on the contact glass 54 is connected to the guide member by a .0.
It is arranged with a gap of about 5 mm ± 0.2 mm, and is pressed against the contact glass 54 with predetermined elasticity. With this configuration, an error in the reading depth direction can be suppressed.

The surface of the contact glass 54 is treated with a surfactant (silicone-based activator) so that ink or the like hardly adheres or adheres. By extending the guide member to the vicinity of the reading position, the document surface does not actively contact the contact glass 54 at the reading position, and
4 is configured to be able to perform wiping (the action of scraping off foreign matter on the glass surface at the tip) around the reading position.

The second reading / conveying section 6 comprises a contact image sensor 61, a pressing member 62 and the like, and reads the back side image from above while conveying the original after the front side reading.

The paper discharge section 7 is composed of a paper discharge drive roller 71, a paper discharge pressure roller 72, a paper discharge sensor 70, and the like, and conveys the original whose front and back sides have been read to the outside or the reverse conveyance section 8. .

The reverse transport section 8 is composed of a reverse switching claw 80, a pair of reverse discharge rollers 81 and 82, and performs a switchback operation for re-reading after reading the front side. Note that the switchback path 83 forms an intermediate stack.

The stack section 9 is composed of a paper discharge stacker 90 and the like, and stacks and holds originals after reading is completed. The discharge stacker 90 is provided with a small-size dedicated stacker 91 for enhancing the visibility of the small-sized document after the discharge and facilitating the removal of the discharged document.

Here, the configuration of the control unit of the ADF 200 of the present embodiment and the image forming apparatus main body 1000 equipped with the ADF 200 will be described.

As shown in FIG. 2, the ADF 200 has a controller 100 for controlling the operation of the ADF.
Detection signals from 9, 28, 29, 32, 34, 40, 70, 84, etc., each motor (for example, a stepping motor) 1
01 to 104, a state signal from the reversing switching solenoid 105, the completed stamp 73, and a control signal (document feed signal, read start signal, etc.) transmitted via the interface unit (serial communication line) 107 with the main body control unit 111. ) Or a table open signal indicating that the document set table 10 is open.

Further, the controller 100 outputs signals based on the detection information from the sensors (a document size signal (width signal, length signal), a registration stop signal, a discharge completion signal, etc.).
Is transmitted to the main body control section 111 and the main body control section 11
1 based on the control signal transmitted from
To 104, the reversing switching solenoid 105, the finished stamp 73
And the like. For example, the document set sensor 28
Detects that the original sheet bundle P is set on the original set table 10, the detection information is transmitted by the controller 100 to the main body control unit 111 as an original set signal via the interface unit 107. Alternatively, when the table opening / closing sensor 15 detects that the document set table 10 of the ADF 200 has been lifted, the detection information is transmitted to the main body control unit 111 as a lift-up signal via the interface unit 107 by the controller 100. Is done.

The controller 100 supplies power to the contact image sensor 61 provided on the ADF side as shown in FIG. Further, the controller 100
Is a timing signal (a front DF gate on / off signal, a surface DF gate on / off signal,
Back DF gate on / off signal, etc.) and turn on / off the light source for exposure.

The contact image sensor 61 includes a light source unit (LED) 208 for exposure when reading an original, and a CCD sensor chip 201 which reads an image surface of the original and photoelectrically converts the information into an electric signal (analog signal). , An amplifier 202 for amplifying the analog signal, and an A / D converter 2 for converting the amplified analog signal into a digital signal
03, an image processing unit 204 for generating image information from the digital signal, a frame memory 205 for expanding and storing the image information, and a main unit control unit via the interface circuit 207 for transferring the image information stored in the frame memory 205. 1
11 and an output control circuit 206 for sending out to the ADF
The exposure processing is performed according to a timing signal from the image forming apparatus, and the acquired image information is transmitted to the image forming apparatus main body 1000 side.

The controller 100 has a RAM (not shown).
The operation mode input and set from the operation unit 108 on the 00 side is stored, and the stored content is updated each time the operation mode is changed. For example, a mixed loading mode in which originals of different sizes are mixed on the original set table 10 and the originals are read at a predetermined transport speed according to the size, a unified size mode in which originals of different sizes are read and output on recording paper of the same size, Duplex / single-sided mode for reading double-sided or single-sided originals,
At the time when the preceding document after reading has passed through the paper ejection sensor 70 (or when it has been conveyed by a predetermined number of pulses after passing through the registration sensor 40), the setting contents such as the advance feeding mode for feeding the next document are stored. In the RAM, the document size in the transport direction calculated based on the detection information of the document length sensors 12 and 14 and the document size in the width direction detected by the width size sensor group 32 are determined in combination. The stored original size is stored.

On the other hand, the main body control unit 111 controls the entire apparatus, detects information signals from various sensors (not shown) on the image forming apparatus main body 1000 side, and input / output units (not shown, such as drive motors and clutches). Status signal from the load),
And various signals from the operation unit 108, signals transmitted from the ADF 200 via the interface unit 107, information signals such as document jams and serviceman calls, and image information from the contact image sensor 61.

The main body control section 111 performs drive control of the input / output section, display control in the operation section 108, and the like based on the information indicated by the signal thus received and input, and also controls the ADF 200 for the operation mode. Or a document feed signal for starting the sheet feeding operation by driving and rotating the pickup roller 20, a reading start signal for starting a reading operation by the contact image sensor 61 in accordance with the transport timing of the ADF 200, and the like. , And instructs the controller 100 to control the feeding / conveying operation (including the advance operation) or the reading speed (conveying speed) of the ADF 200. In particular, only when a pause is required depending on the state of the image forming apparatus main body 1000, such as synchronization with an image memory or transfer paper jam in the advance mode, the reading start signal is not transmitted before the reading position of the document is read. Control is performed so that the transport loss due to the previous temporary stop is minimized.

The operation unit 108 includes various button keys such as a start button and numeric keys (not shown), an LCD, and the like.
Display, etc., the mixed mode, single-sided / double-sided mode,
It is configured such that the setting of each operation mode such as and the like and the instruction of operation start / stop can be performed by a user operation. For example, when the start button is pressed after the document set is detected by the main body control unit 111, the pressed information is transmitted to the main body control unit 111.
A start signal (document feed signal) is transmitted to the ADF 200 based on the pressed information. By transmitting the start signal in this way, AD
In F200, the pickup roller 20 is automatically driven and rotated to start the sheet feeding operation, and the image forming apparatus main body 1000
The reading operation is performed by the first reading / transporting unit 5 on the ADF side and the second reading / conveying unit 6 on the ADF side.

When each of the motors 101 to 104 is composed of a stepping motor, for example, the driving amount can be easily obtained by counting the number of pulses and multiplying the driving amount per pulse. Based on the above, the length of the original is detected, the transport interval (sheet interval) between the preceding original and the next original, the reading position arrival timing control, the reading operation end timing control, and the like are performed.

As shown in FIG. 5, the pickup roller 2
0 is driven up and down by a lifting drive mechanism 120.

The raising / lowering drive mechanism 120 includes the
The toothed wheels 121 and 123 are rotated via a toothed wheel 101a attached to the output shaft 1 and a toothed transmission belt 122 (timing belt) having teeth formed on an inner peripheral portion thereof. The toothed wheel 123 is connected to a pickup input gear 125 via a shaft member 124. The gear 125 meshes with a pickup drive gear 126, and the pickup drive gear 126 can rotate the drive cam 131 by the rotational power from the gear 125. When the ringing motor 101 rotates in one direction, the pickup driving gear 126 rotates in the R1 direction in FIG. 5 via the belt 122 and the pickup input gear 125.

Drive shaft 129 for rotating drive cam 131
Is mounted with a filler 128 for detecting a home position, and is rotatably supported by a bracket 211 (only a part is shown) constituting a part of the frame of the ADF 200. The home position sensor 19 provided in the vicinity of the filler 128 includes a light emitting element and a light receiving element. When light emitted from the light emitting element to the light receiving element is blocked by the filler 128,
It is detected that the pickup roller 20 has retracted to the upper stop position (up position), which is the home position.

As shown in FIGS. 6 and 7, the drive cam 131 is provided with a cam follower lever 133 provided at one end of the pickup drive member 133 (drive transmission member).
The pickup driving member 133 is supported by a paper feed belt drive shaft 134 that drives the paper feed belt 23. And the driving cam 1
When the rotating member 31 rotates while abutting on the cam follower lever portion 133a, the pickup driving member 133 rotates around the sheet feeding belt driving shaft 134. The pickup driving member 133 does not necessarily need to be supported on the same axis as the sheet feeding belt driving shaft 134. However, if the pickup driving member 133 is supported on the same axis, the sheet feeding conveyance path can be simplified, and the conveyance of the separation sheet feeding unit 2 can be simplified. It is possible to easily remove the jam document on the road.

An up / down driving lever 133b is provided at the other end of the pickup driving member 133.
The lifting drive lever portion 133b swings the swing member 135 in accordance with the rotation of the pickup drive member 133. Specifically, the swing member 135 includes a swing support shaft 135a rotatably supported by a bracket 138 that houses the paper feed belt 23, an end 135b that rotatably supports the pickup roller 20, and Lift drive lever portion 1 provided on pickup drive member 133
The other end 135c slidably engaged with the slot of 33b.
And The bracket 138 is rotatably supported at its base end by a feed belt drive shaft 134 in the vertical direction, and rotatably supports the driven pulley 22 at its tip end. Is wound around the driven pulley 22 and the drive pulley 24 fixed to the feed belt drive shaft 134, and the feed belt drive shaft 134
It is driven by the rotation of. An idle gear 137 for driving the pickup roller 20 is attached to the swinging member 135. The idle gear 137 meshes with a gear 20a formed at an end of the pickup roller 20, and the driven pulley 22 The gears 20a, 137 and 22a are always meshed with each other,
The rotation from the feed belt drive shaft 134 is transmitted to the pickup roller 20.

As shown in FIG. 8, the driven pulley 2
A cylindrical member 145 is inserted between the swing member 135 and the swing support shaft 135a of the swing member 135, and compression springs 146a, 146 are provided between both ends of the cylindrical member 145 and the bracket 138.
46b is contracted. These springs 146a,
Reference numeral 146b designates the driven pulley 22 as a feed belt driving shaft 134.
The paper feed belt 2 is urged in a direction away from the paper feed belt 2.
3 is given a constant tension. The feed belt 23 also has a function of pressing the bracket 138 against bearings 24a and 24b at both ends of the drive pulley 24. Therefore, when the springs 146a and 146b are contracted, the tension of the feed belt 23 is released, and the feed belt 2 is released.
3. The feed belt drive shaft 134 and the driven pulley 22 can be removed from the bracket 138.

When the feed belt 23 is wound around the feed belt drive shaft 134 and the driven pulley 22 with a predetermined tension, both the driven pulley 22 and the bracket 138 supporting the driven pulley 22 are fed. Drive shaft 1
The rotation of the pickup roller 20 is restricted, but the pickup roller 20 is normally urged downward by its own weight. Specifically, a torsion spring 141 having a low spring constant for urging the swing member 135 toward the lower side of the pickup roller 20 with respect to the bracket 138 is mounted around the swing support shaft portion 135a of the swing member 135. The torsion spring 141
Is lower than or equal to the weight of the pickup roller 20 by its own weight. Accordingly, due to the weight of the pickup roller 20, the gear 137, and the like, as shown in FIG. 7A, the swing member 135 is urged in the counterclockwise direction in FIG. 7 to tilt, and the cam follower lever portion 133a is driven by the driving cam. 13
1. And the driving cam 13
1 rotates, the pickup driving member 133 rotates downward, and as shown in FIG.
Raises the pickup roller 20 to the retraction side via
It can be separated from the original sheet bundle P.

The pick-up roller 20 moves the original sheet bundle P
The home position sensor 19 detects the filler 128 and outputs an evacuation detection signal to the controller 100 when the evacuation is made to the upper stop position, which is the uppermost evacuation position away from the controller. Then, based on the evacuation detection information from the home position sensor 19, the controller 100
It is determined that the pickup roller 20 has risen to the upper stop position.

The driving motor 13
1 as well as the pickup driving member 133 and the swinging member 135 for raising and lowering the pickup roller 20 in accordance with the output thereof, as a whole, the lifting side so as to separate the pickup roller 20 from the uppermost document sheet. To the pickup roller 2
The lifting means 140 is configured to lower the pickup roller 20 by allowing 0 to be lowered by a predetermined urging force including its own weight, thereby changing the height of the pickup roller 20 on the document set table 10.

The driving force of the paper feeding motor 102 driven based on a command signal from the controller 100 is supplied to a paper feeding belt driving shaft 134 and a separation roller via a toothed pulley, a timing belt, a one-way clutch and gears (not shown). 26 respectively.
Further, the driving force of the paper feed motor 102 is also transmitted to the reading and conveying roller 43 via an electromagnetic clutch, a one-way clutch and the like (not shown).

On the other hand, as shown in FIG.
Has a cam shape capable of moving the pickup roller 20 up and down and temporarily stopping the descending pickup roller 20 or reducing the descent speed of the pickup roller 20 by its rotation.

More specifically, the driving cam 131 has a first cam surface 131a having a maximum radius that is the maximum lift La and a second cam surface 13a having an intermediate lift Lb that is smaller than the maximum lift La.
1b and a third cam surface 131c having a minimum radius that is a minimum lift Lc smaller than any of the lifts La and Lb. When the drive cam 131 rotates counterclockwise in FIG. From the first cam surface 131a to the second cam surface 131
b, the third cam surface 131c and the pickup driving member 1 sequentially
33 and a cam follower lever portion 133a in order from the first cam surface 131a.
a.

The drive cam 131 may be separated from the third cam surface 131c by a gap when the minimum lift of the third cam surface 131c faces the cam follower lever 133a. That is, when the original sheet bundle P is in the thinnest state, for example, one sheet, the driving cam 13
1 and the cam follower lever 133a are always in contact with each other while the contact portion between them is from the first cam surface 131a to the second cam surface 131b, and from the second cam surface 131b to the third cam surface 131b.
At the stage leading to c, both may be completely separated on the way. In that case, the cam follower lever 1
33a, the tip of the cam follower lever 133a rises higher than the center of rotation of the drive cam 131 when facing the third cam surface 131c, and the cam follower lever 133a is pushed down from the time when the first cam surface 131a abuts again. You may hit with a structure. When such a configuration is adopted, the installation space for the driving cam is limited, and even if the height difference between the first cam surface 131a and the third cam surface 131c cannot be obtained by a predetermined amount, the pickup roller 2
An ascending / descending amount of 0 can be secured. However, when the cam follower lever 133a is shortened and separated from each other as described above, the height difference between the second cam surface 131b and the third cam surface 131c increases, and the drive cam 131 is rotated forward and reverse as described later. In this case, it is difficult to rotate the cam follower lever 133a, and it is difficult to normally move the pickup roller 20 up and down. In the present embodiment, the configuration in which the third cam surface 131c and the cam follower lever 133a are in contact with each other is described as an example for ease of description.

The angle range of each of the first to third cam surfaces 131a to 131c and the shape of the connecting portion between them are determined according to the ascending and descending timing of the pickup roller 20, the ascending and descending speed, and the ascending and descending speed change pattern. 2 cam surface 1
31b preferably has a radius that provides a lift closer to the third cam surface 131c than to the first cam surface 131a. Further, when the driving cam 131 rotates at a constant speed, the contact between the cam follower lever 133a and the driving cam 131 is changed from the first cam surface 131a to the second cam surface 131b.
When the pickup roller 20 descends without abutting on the original sheet bundle P during the transition to, that is, when the number of stacked original sheet bundles P is small, the contact point between the cam follower lever portion 133a and the drive cam 131 becomes the second position. When the pickup roller 20 reaches the cam surface 131b, the lowering speed of the pickup roller 20 is substantially temporarily stopped or reduced to a degree close to the stop.

When the first cam surface 131a of the driving cam 131 is in contact with the cam follower lever 133a, the cam follower lever 133a swings the swing member 135 to raise the pickup roller 20. At this time, when the pickup roller 20 comes to a high position (height h1 on the mounting table) shown in FIG. 4C, a large number of documents can be set.

When the second cam surface 131b of the drive cam 131 is in contact with the cam follower lever portion 133a, when the
As shown in (b), the pickup roller 20 has a height h.
It remains at a height h2 (h2 <h1) lower than 1. As described above, when the pickup roller 20 descends from the high position to the calling position, the kinetic energy of the pickup roller 20 once becomes zero by stopping at the intermediate height h2. The sound of the impact is reduced.

When the third cam surface 131c of the driving cam 131 comes into contact with the cam follower lever portion 133a, the pickup roller 20 comes into contact with the document set table 10 or before it comes into contact with the document sheet bundle P and mainly by its own weight. The original sheet bundle P is pressed. The rotation of the pickup roller 20 is driven by the sheet feeding motor 102 which is a driving source different from the lifting / lowering means 140. By raising and lowering the pickup roller 20 by a driving system independent of the feeding rotation, a paging operation is performed. It is possible to prevent a malfunction such as an unintended operation.

As described above, since the position of the pickup roller 20 is determined by the position of the drive cam 131, the sensor 19 detects the filler 128 which rotates together with the drive cam 131, so that the pickup roller 20 can be raised or lowered. The reference position at the time can be determined. Further, the lever portion 133a of the pickup driving member 133 is attached to the feed belt driving shaft 134, and a new shaft for rotating the pickup driving member 133 is not provided. By arranging such a mechanical component on the upper side of the paper section 2, the current removal at the time of misfeed is facilitated.

When the calling motor 101 is a stepping motor, the driving cam 131 is counted by counting a predetermined number of pulses based on the detected position of the filler 128.
And the height of the pickup roller 20 can be controlled. Further, as shown in FIG. 10, when the plurality of sensors 19a and 19b are attached to the drive shaft 129, when the pickup roller 20 is almost completely lowered, when the pickup roller 20 is raised to the intermediate retract position, the upper stop is stopped. You can control each time you are in the position. In this case, there is no need to use a stepping motor, and the motor control can be simplified.

((Transportation operation))

Next, the operation of separating and transporting the original sheet bundle according to the present embodiment will be described.

First, the original sheet bundle P to be read is set on the original set table 10 with its leading end abutting on the broken line position of the original stopper 25. Further, the side guides 11 on the left and right sides of the original sheet bundle P Position in the width direction.

In this state, the original set detection filler 21
Moves from the broken line position to the solid line position in FIG. 1, the light shielding of the document set sensor 28 is released, the document set is detected, and a document set signal is transmitted to the main body control unit 111 via the interface unit 107. Is done. Further, a first original length sensor 12 provided on the original set table surface is provided.
Alternatively, the second document length sensor 14 determines the approximate length of the document in the transport direction.

Thereafter, a document feed signal (input from the operation unit 108 and sent from the main unit control unit 111 to the interface unit 10)
7 is a signal for instructing the controller 100 to feed paper)
Thus, the document feeding operation shown in FIGS. 11 and 12 is performed.

First, the setting of a document is detected (step S 1). If the document sheet is not set on the document set table 10, the current process is terminated, but if the document sheet is set on the document set table 10. If
The call motor 101 is driven forward (CW) (step S2), the pickup roller 20 is lowered from the upper stop position, the pickup roller 20 is moved from the broken line position to the upper surface of the original document indicated by the solid line position, and the original sheet bundle P is self-weighted. When pressure is applied at a predetermined pressure, the calling operation is performed (Yes in step S3), and the calling motor 101 is stopped (step S4).

It should be noted that detecting that the pickup roller 20 has moved to the calling position is performed by the calling motor 10.
This is possible by detecting one pulse. When the ringing motor 101 is normally rotated by a predetermined pulse from the position detected by the home position sensor 19, that is, the position where the first cam surface 131a of the driving cam 131 faces the cam follower lever portion 133a. The drive cam 131 rotates to a position where the third cam surface 131c faces the cam follower lever portion 133a, and the pickup roller 20 becomes movable to a lowermost position where the pickup roller 20 comes into contact with the document set table 10. As another detection method, a sensor similar to the home position sensor 19 is used.
The third cam surface 131c is a cam follower lever portion 133a.
By installing at a position that detects that it is facing
It is also possible to determine whether or not the sensor has contacted the original sheet bundle P by determining whether or not the sensor has detected.

Then, after a predetermined time, the separation sheet feeding section 2
The feed motor 102 for driving the registration unit 3 is driven to rotate forward (step S4), and the pickup roller 20 is driven.
Is rotated clockwise to feed the uppermost original sheet from the uppermost position of the original sheet bundle P toward the separation sheet feeder 2 (step S5). At this time, the separation roller 26 is driven via a torque limiter (not shown) having a predetermined torque, and is directly engaged with the paper feed belt 23 or engaged with one document. Then, feed belt 2
It is rotated by the rotation of 3.
When the paper enters between the paper feed belt 23 and the separation roller 26, the frictional resistance of the lower original sheet based on the load torque of the torque limiter is larger than the frictional resistance between the original sheets. It rotates and pushes back the lower excess document sheet taken out by the uppermost document sheet to prevent double feeding.

The document separated into one sheet by the action of the paper feed belt 23 and the separation roller 26 is further conveyed by the paper feed belt 23 and advances in the paper feed path 27. In this process, when the front end is detected by the abutment sensor 29 (yes in step S6), the abutment is performed on the stopped registration roller 30. Here, in order to abut the document by a predetermined amount, the count of the number of drive pulses of the paper feed motor 102, that is, the so-called abutting count is started (step S9). If the predetermined time has elapsed without the abutment sensor 29 being turned on in the step S6 (step S7), a predetermined abutment unreachable jam process is executed (step S8).

When the hit count is started,
By rotating the calling motor 101 forward (step S10), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and it is determined whether the pickup roller 20 has reached a predetermined retract position (step S11). ). If the result of the determination is yes, the calling motor 101 is stopped (step S12).

During this time, by feeding the original sheet only by the conveying force of the paper feed belt 23, the leading end of the original sheet enters the nip portion of the pair of upper and lower rollers of the registration roller 30, and the alignment of the leading end (correction of abutting skew) is performed. Done.

After the calling motor 101 stops, the original sheet is detected by the abutment sensor 29 and fed to the sheet feeding motor 10.
The sheet is conveyed by a predetermined distance (predetermined number of pulses) in the forward rotation of 2, and at this time, it is determined whether or not the abutting count amount is the predetermined number of pulses (step S13). Is stopped, and the driving of the paper feed belt 23 is stopped (step S14).

Next, the registration roller 30 is driven by the normal rotation of the reading motor 103, and the document sheet is conveyed in the direction of the reversing section 4 (step S15). If the hit sensor 29 has been turned off for a predetermined period of time and the time has expired in step S7, it is determined that a jam has been detected, and the fact that the jam has not been reached is displayed on the operation unit 108.

((Image reading))

The document whose registration is stopped, or the reading / conveying roller 43 and the pressure roller 4 without stopping the registration.
The document sent to the nip portion of the main body 1 is
Then, based on a reading start signal from the controller to the controller 100, the reading roller 103 and the pressing roller 41 which are rotated by the forward rotation of the reading motor 103 are fed to the first reading and conveying unit 5.

The timing at which the leading edge of the document arrives at the reading / transporting section 5 is controlled by the pulse count of the reading motor 103. At this timing, a front DF gate-on signal indicating the effective reading area of the front image in the sub-scanning direction is transmitted. . Thereafter, the original is conveyed while reading, and is sent to the intermediate conveyance pressurizing roller 53 via the pickup guide 52. The intermediate transport pressure roller 53 and the pressure roller 41
Is a common drive by the reading and conveying roller 43,
The feed and withdrawal speeds are the same, which has the effect of reducing the occurrence of delivery shocks.

The original sent from the first reading / conveying unit 5 by the intermediate conveying / pressing roller 53 is sent to the second reading / conveying unit 6 for reading the back surface, and is arranged above the conveying path with the reading unit facing downward. It passes between the contact image sensor 61 and a pressing member 62 which is opposed to the reading surface of the contact image sensor 61 below the conveyance path and is disposed at a predetermined pressure and a predetermined interval.

In the case of the duplex mode, the timing at which the leading edge of the document reaches the reading position by the close contact image sensor 61 is controlled by the conveyance pulse count from the leading edge detection of the registration sensor, and the effective reading area of the back side image is notified at that timing. Therefore, a backside DF gate-on signal is transmitted to the contact sensor unit. Based on this signal, the image of the surface corresponding to the back side of the document is read, converted into an electric signal as in the case of the front side, temporarily stored in the frame memory 205 shown in FIG. The pressing member 62 serves as a reference for shading and acts as a white background plate. The pressing member 62 is formed of a plate-shaped guide member in FIG. 1, but may be formed of a rotating body.

Thus, a predetermined reading operation is performed (step S16).

The timing of terminating the original reading areas on the front and back sides is controlled by pulse counting from the time when the leading edge of the original is detected by the paper discharge sensor 70 and the trailing end of the original is detected by the registration sensor 40. Then, when the trailing end of the document sheet that has passed the image reading position is detected by the paper discharge sensor 70 (step S17), the next document feed signal is generated (step S18).

Thereafter, the read original sheet is discharged to the stack section 9 by the discharge drive roller 71 and the discharge pressure roller 72. Note that the discharge stacker 90 is configured to be higher on the downstream side, which contributes to prevention of discharge document jumping out and improvement of stack document alignment accuracy.

In the continuous reading of a plurality of originals, the drive of the reading motor 103 is stopped by the registration stop operation by the next original advance operation before the original discharge completion timing. Therefore, the operation of discharging the read original is started by reading the next original. When the trailing edge of the original passes through the paper ejection sensor 70 by resuming the driving of the reading motor 103, the controller 10
From 0, a paper discharge completion signal is transmitted to the main body control unit 111, and the processing is completed.

When a small-size document is stacked, the reversing switching claw 80 of the reversing conveyance section 8 is set to the reversing switching solenoid 105.
Is switched to the state shown by the broken line, and the original is conveyed to the switchback path 83 and discharged from the pair of reverse discharge rollers 81 and 82 onto the small-size dedicated stacker 91 formed as a part of the discharge stacker 90. Thereby, the visibility after discharge is improved. At this time, the stack document can be easily taken out by rotating and retracting the document set table 10 around the rotation fulcrum 95 upward.

When the original is ejected, the operation of the inversion switching claw 80 is synchronized with the trailing end of the ejected original, and immediately after the original is ejected, the inversion switching claw 80 is rotated in the direction of the broken line by the inversion switching solenoid 105. Control is performed to prevent the trailing end of the discharged document from remaining by hitting the trailing end of the discharged document.

The above is the operation when the original sheet bundles P of the same size are separated and conveyed, and the conveying operation in the mixed loading mode for conveying the original sheet bundles P having different sizes is also possible. Omit.

((Action))

As described above, in the present embodiment, the pickup roller 20 which contacts the upper part of the original sheet bundle P placed on the original set table 10 and calls the upper original sheet to the separation position, A separation sheet feeding unit 2 for separating the uppermost sheet from the lower sheet among the sheets called to the separation position by the pickup roller 20
And the pickup roller 2 on the document set table 10
ADF provided with elevating means 140 for changing the height of zero
In 200, the lifting unit 140 stops the lifting of the pickup roller 20 at the highest upper stop position of the lifting range of the pickup roller 20, and selectively stops when the pickup roller 20 is lowered from the upper stopping position. The lowering operation of temporarily stopping the lowering of the pickup roller 20 or reducing the lowering speed of the pickup roller 20 is executed.

Therefore, before the original document is set, the elevation of the pickup roller 20 is stopped at the highest upper stop position in the elevation range of the pickup roller 20, so that the thick original sheet bundle can be fed. Become. Also,
When the pickup roller 20 descends from its upper stop position, the descent of the pickup roller 20 is temporarily stopped or the descent speed is decreased, so that the substantial drop start position of the pickup roller 20 is lowered. Similarly, it is possible to reduce the impact noise.

In the present embodiment, the pickup roller 20 is located at a position higher than the position where the pickup roller 20 contacts the original sheet bundle P on the original set table 10 and the upper stop position and the intermediate stop for temporarily stopping the lowering of the pickup roller 20. The pickup roller 20 is dropped from one of the lower positions. In other words, the drop start height of the pickup roller 20 is higher than the position where the pickup roller 20 comes into contact with the sheet bundle on the document set table 10 and the upper stop position and the intermediate stop position for temporarily stopping the lowering of the pickup roller 20. Any of the lower positions, the height at which the pickup roller 20 is retracted can be freely set within the height range from the intermediate stop position to the upper stop position if it is higher than the contact position with the sheet bundle. In addition, it is not necessary to precisely control the retracting height according to the height of the sheet bundle. As a result, it is possible to reduce the hitting sound and the impact sound at the time of falling by setting the substantial drop start position of the pickup roller 20 within a predetermined height range from the document sheet bundle P without finely controlling the retreat height. it can.

Further, in this embodiment, the pickup roller 20 is driven up and down by the drive cam 131, so that it is possible to drive up and down quickly, and how to adjust the retracting speed and the descending speed by the cam shape. It is a simple elevating means 140 that can be set. Also, since it is sufficient to simply rotate the driving cam 131 in one direction,
No complicated drive control is required. Moreover, the driving cam 131
By providing the cam surface 131b in a predetermined angle range where the radius (lift) is constant, the height of the pickup roller 20 can be kept constant during the rotation of the driving cam 131, or the lift Lb can be adjusted to an angle. As a configuration that changes according to the position, the lifting speed of the pickup roller 20 can be appropriately adjusted.

Incidentally, as shown in FIG.
Fillers 128a and 128b that rotate together with the first roller 1, a sensor 19a as first cam position detecting means for detecting the filler 128a when the pickup roller 20 is at the uppermost stop position that is the uppermost retreat position, and a pickup roller 20. Is provided with a sensor 19b as a second cam position detecting means for detecting the filler 128b when it is at the intermediate retreat position lower than the upper stop position, if the elevating means 140 is provided with detection information of the sensors 19a and 19b. The driving cam 131 can be rotated on the basis of this, and the simple operation of the sensors 19a and 19b for detecting the rotational angle positions of the fillers 128a and 128b can be used to switch the evacuation operation and determine whether or not it is necessary.

Further, in the above operation, the driving cam 131 is rotated in one direction. However, the above-described elevating means 140 rotates the driving cam 131 reciprocally in one direction and the other side in the rotation direction. The pickup roller 20 may be moved up and down only in a part of the range in which it can be moved up and down.

In this case, there is a dedicated mode when the number of originals placed is one (or a small number) (in the case of one,
It is not necessary to raise the pickup roller 20 to its maximum height. Therefore, the second cam surface 131b and the third cam surface of the driving cam 131 are provided to the lever portion 133a of the pickup driving member 133. By controlling the driving cam 131 so that the driving cams 131c abut alternately, the retraction height can be reduced, and the original setting table can be used in order to cope with an order of only one copy (or only a small number of copies) in advance. The shock generated when the pickup roller 20 falls on the front end side guide plate portion (not shown in detail) of the pickup 10 can be reduced, and the sound of the shock can be reduced.

In the above-described embodiment, the elevation is controlled by detecting the approximate height of the pickup roller 20 when it is stopped or retracted. However, as shown in FIG. In the vicinity of the pickup roller 20,
A sensor 151 for detecting the height of the document can be provided.

[Second Embodiment]

FIG. 13 and FIG. 14 show that a document height sensor 151 composed of, for example, a reflection type sensor is provided as a sheet height detecting means for detecting such a document height. A second embodiment in which the first retracting operation up to the uppermost stop position and the second retracting operation up to the intermediate retracting position are switched and executed based on the detection information of the second embodiment. It is a flowchart of a paper operation.

The operation of transporting the original sheet bundle P in the present embodiment will be described. First, the original sheet bundle P to be read is set on the original set table 10 with the leading end abutting on the broken line position of the original stopper 25. Further, positioning in the width direction is performed by the left and right side guides 11 of the original sheet bundle P. At this time, the original set detection filler 21 moves, the light shielding of the original set sensor 28 is released, and the setting of the original is detected.
1, a document set signal is transmitted.

Next, in response to a paper feed command signal from the main body control section 111 to the controller 100, FIGS.
Is performed.

First, the setting of the document is detected (step S21). If the document sheet is not set on the document set table 10, the current process is terminated (no in step S21). 1
If it is set to 0, it is then determined whether or not the document height is higher than a predetermined height (step S22). If the determination result is yes, then the calling motor 10
1 is driven forward (CW) (step S24). If the result of the determination is no, then it is determined whether or not a flag indicating that the document height is low is set (step S23). If the flag has been set, the process proceeds to step S24.

In step S23, if the flag is not set, it means that the height of the original sheet bundle P is first detected after the original is set. Here, the calling motor 101 is driven to rotate forward (step S25), and it is repeatedly checked whether or not the position of the pickup roller 20 is at a height corresponding to the lift amount Lb of the second cam surface 131b (step S26). When the height reaches the height corresponding to the lift amount Lb (yes in step S26), the calling motor 10
1 is stopped (step S27), and a predetermined process for setting a flag indicating that the document height is low is executed. Then, the process proceeds to step S24.

The detection that the pickup roller 20 has moved to the calling position is realized by detecting the pulse of the calling motor 101 as in the first embodiment. However, unlike the first embodiment, the standby position of the pickup roller 20 changes depending on the number of originals. For example, when there is no small-number-sheet loading flag, the pickup roller 20 is driven by a predetermined number of pulses as in the first example, When the placement flag is set, the cam follower lever 133a
It is sufficient to drive the ringing motor 101 in the forward direction by the number of pulses enough for the cam surface opposing to the second cam surface 131b to move to the third cam surface 131c. As another method, a sensor similar to the home position sensor 19 is added to a position where the third cam surface 131c detects that the third cam surface 131c faces the cam follower lever portion 133a, and whether or not the sensor detects the third cam surface 131c is detected. , It can be determined whether or not the original sheet bundle P has come into contact. In this case, there is no need to determine the minority sheet placement flag.

In step S24, the calling motor 101
Rotates forward, the pickup roller 20 moves down from the upper stop position and moves to the upper surface of the document, and presses the document sheet bundle P with a predetermined pressure of about its own weight (step S29).
(Yes), the calling motor 101 is stopped (step S30).

Thereafter, after a predetermined time, the separation sheet feeding section 2
The paper feed motor 102 for driving the registration unit 3 is driven to rotate forward (step S31), and the pickup roller 20 is rotated.
Feeds and rotates to feed the uppermost original sheet from the uppermost position of the original sheet bundle P toward the separation sheet feeding unit 2.

The document separated into one sheet by the action of the paper feed belt 23 and the separation roller 26 is further conveyed by the paper feed belt 23 and advances in the paper feed path 27. In this process, when the front end is detected by the abutting sensor 29 (yes in step S32), the abutting sensor 29 further abuts against the stopped registration roller 30. Here, in order to hit the document by a predetermined amount, a hit count is started based on the number of drive pulses of the paper feed motor 102 (step S).
35). If the predetermined time has elapsed without the abutment sensor 29 being turned on in step S32, it is determined that the time is over (yes in step S33), and a predetermined abutment unreachable jam process is executed (step S34).

When the hit count is started,
It is checked whether or not a flag indicating that the document height is low is set (step S36). If the flag is set (yes in step S36), then the calling motor 101 is rotated in reverse ( Step S37), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and the pickup roller 20 is moved to a predetermined position corresponding to the lift amount Lb of the second cam surface 131b of the driving cam 131 (in FIGS. (step S3).
8). If the result of the determination is yes, the calling motor 101 is stopped (step S39).

On the other hand, if the decision result in the step S36 is no, that is, if the flag indicating that the document height is high and the document height is low is not set, then the calling motor 101 is rotated forward. (Step S40), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and the pickup roller 20 is moved to the first cam surface 131a of the drive cam 131.
It is determined whether or not the retract position (upper stop position) corresponding to the lift amount La has been reached (step S41). And
If the determination result is yes, the calling motor 101
Is stopped (step S42).

During this time, by feeding the original sheet only by the conveying force of the paper feed belt 23, the leading end of the original sheet enters the nip portion of the pair of upper and lower rollers of the registration roller 30, and the alignment of the leading end (correction of abutting skew) is performed. Done.

After the calling motor 101 is stopped, the original sheet is detected by the abutment sensor 29 and fed to the sheet feeding motor 10.
In the forward rotation of No. 2, it is transported by a predetermined distance (predetermined number of pulses). At this time, it is determined whether or not the abutment count amount is the predetermined number of pulses (step S43).
The paper feed motor 102 is stopped, and the paper feed belt 23 is stopped (step S44).

Next, the registration roller 30 is driven by the normal rotation of the reading motor 103, the original sheet is conveyed in the direction of the reversing section 4 (step S45), and the original sheet is determined by at least one of the image forming apparatus main body 1000 and the contact image sensor 61. Is performed (step S
46). Then, when the trailing end of the document sheet that has passed the image reading position is detected by the paper discharge sensor 70 (step S47), the next document feed signal is generated (step S47).
48).

As described above, in this embodiment, the elevating means 1
40 is a first retracting operation for retracting the pickup roller 20 to the uppermost retracted position (upper stop position) in accordance with the height of the original sheet bundle P on the document set table 10, and One of the second retraction operation for retreating to the lower intermediate stop position is performed, and the retraction height of the pickup roller 20 from the uppermost sheet is adjusted to a certain height or less.
Therefore, effects similar to those of the above-described embodiment can be obtained.
In addition, according to the height of the document sheet bundle P, it is possible to switch between the first retreat operation, which is the retreat of the maximum height, and the second retreat operation having a lower retreat height at a required timing. The noise can be further reduced by keeping the retracting height low.

A plurality (three or more) of retreat heights corresponding to the thickness of the original sheet bundle P can be finely set. Further, since it is possible to perform finer elevation drive control of the pickup roller 20 according to the sheet height, by raising and lowering the pickup roller 20, for example, the contact time between the pickup roller 20 and the original sheet can be constantly called. It can also be controlled to an optimal range.

The sheet height detecting means is not limited to the one which directly detects the height of the sheet bundle on the original set table 10, but detects the operation position of the pickup roller 20 and other members in detail, thereby picking up the sheet. Roller 2
The height of the sheet bundle near zero may be indirectly detected.

[Third Embodiment]

FIGS. 15 and 16 show that the operation unit 108 enables the setting operation of the multi-sheet stacking mode and the small-number sheet stacking mode for the document stacking, and the uppermost stop position according to the mode setting state. 13 is a flowchart of the sheet feeding operation according to a third embodiment in which the first retreat operation and the second retreat operation to an intermediate retreat position are switched and executed.

The operation of transporting the original sheet bundle P in this embodiment will be described. First, as in the above-described case,
The original sheet bundle P to be read is placed on the original set table 10.
The document sheet bundle P is set with its leading end abutting on the broken line position of the document stopper 25, and is further positioned in the width direction by the left and right side guides 11 of the document sheet bundle P. At this time, the original set detection filler 21 moves, the light shielding of the original set sensor 28 is released, the original set is detected, and an original set signal is transmitted to the main body control unit 111.

Next, in response to a paper feed command signal from the main body control unit 111 to the controller 100, FIGS.
Is performed.

In the document feeding operation, first, the setting of the document is detected (step S51), and if the document sheet is not set on the document set table 10, the current process is terminated (step S51: no). If a document sheet is set on the document set table 10, it is then determined whether or not the document stacking mode is the multi-sheet stacking mode (step S52). If the result of the determination is yes, the call motor 101 is driven forward (step S54). If the result of the determination is no, then it is determined whether or not the minority sheet placement flag is set. (Step S53), and if the minority sheet placement flag is set, the process proceeds to Step S54.

In step S53, if the minority sheet placement flag is not set, it means that the height of the original sheet bundle P is first detected after the original is set. here,
The calling motor 101 is driven to rotate forward (step S5).
5) The position of the pickup roller 20 is the second cam surface 13
It is repeatedly checked whether it is at the height corresponding to the lift amount Lb of 1b (step S56). When the height reaches the height corresponding to the lift amount Lb (yes at step S56), the calling motor 101 is stopped (step S56). S57) Then,
After performing a predetermined process of setting the minority sheet placement flag (step S58), the process proceeds to step S54.

When the calling motor 101 rotates forward in step S54, the pickup roller 20 moves down from the upper stop position to the upper surface of the original, and presses the original sheet bundle P with a predetermined pressure of about its own weight (step S54). Y in S59
es), the calling motor 101 is stopped (step S60).

Thereafter, after a predetermined time, the separation sheet feeding section 2
The feed motor 102 for driving the registration unit 3 is driven to rotate forward (step S61), and the pickup roller 20 is driven.
Feeds and rotates to feed the uppermost original sheet from the uppermost position of the original sheet bundle P toward the separation sheet feeding unit 2.

The document separated into one sheet by the action of the paper feed belt 23 and the separation roller 26 is further conveyed by the paper feed belt 23 and advances in the paper feed path 27. In this process, when the front end is detected by the abutment sensor 29 (yes in step S62), the abutment is performed on the registration roller 30 which is further stopped and abuts. Here, in order to hit the document by a predetermined amount, a hit count is started based on the number of drive pulses of the paper feed motor 102 (step S).
65). If the predetermined time has elapsed while the butting sensor 29 is not turned on in step S62, it is determined that the time is over (yes in step S63), and a process for a predetermined but not reached jam is executed (step S64).

When the hit count is started,
It is checked whether or not the minority sheet placement flag is set (step S66). If the flag is set (yes in step S66), then the calling motor 1 is set.
01 is reversed (step S67), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and the pickup roller 20 is moved to a predetermined position corresponding to the lift amount Lb of the second cam surface 131b of the driving cam 131. (Step b68 in FIGS. 15 and 16). If the result of the determination is yes, the calling motor 101 is stopped (step S69).

On the other hand, if the decision result in the step S66 is no, that is, if the document height is high and the small-number-sheet placing flag is not set, then the calling motor 101 is rotated forward to ( Step S70),
The pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and whether the pickup roller 20 has reached a retracted position (upper stop position) corresponding to the lift amount La of the first cam surface 131a of the drive cam 131 is determined. It is determined (step S71). Then, the determination result is ye
If it is s, the calling motor 101 is stopped (step S72).

During this time, the original sheet is fed only by the conveying force of the paper feed belt 23, so that the leading end of the original sheet enters the nip portion of the pair of upper and lower rollers of the registration roller 30, and the leading end is aligned (abutment skew correction). Done.

After the calling motor 101 stops, the original sheet is detected by the abutment sensor 29 and fed to the sheet feeding motor 10.
In the forward rotation of No. 2, it is transported by a predetermined distance (predetermined number of pulses). At this time, it is determined whether or not the abutment count amount is the predetermined number of pulses (step S73).
The paper feed motor 102 is stopped, and the paper feed belt 23 is stopped (step S74).

Next, the registration roller 30 is driven by the normal rotation of the reading motor 103, and the original sheet is conveyed in the direction of the reversing section 4 (step S75), and is determined by at least one of the image forming apparatus main body 1000 and the contact image sensor 61. Is performed (step S
76). Then, when the trailing end of the document sheet that has passed the image reading position is detected by the paper discharge sensor 70 (step S77), the next document feed signal is generated (step S77).
78).

As described above, in the present embodiment, the operation unit 10
8 functions as sheet height input means for setting by manual operation input that the number of original sheets placed on the original set table 10 is less than or equal to a predetermined number in the small number original conveying mode. When a sheet is placed on the original set table 10 when the input means has input that the mode is the small-number original transport mode,
The elevating means 140 sets the lowering start position of the pickup roller 20 based on the input information of the sheet height input means. In addition, the lifting / lowering means 140 is configured to control the pickup roller 20 based on the input information of the sheet height input means.
The descent start position is set at least once for the first time, and the descent start position may be set for the second and subsequent times in consideration of another condition.

Therefore, if the user sets a low sheet height by manual operation input, at least the first descent start position of the pickup roller 20 is set based on the input information. The shunting position can be easily switched to enable quick copying operation and the like when necessary.

[Fourth Embodiment]

FIGS. 17 and 18 show a filler 128 as an intermediate retract height detecting means for detecting that the pickup roller 20 has reached the intermediate retract position lower than the upper stop position.
13 is a flowchart of a sheet feeding operation according to a fourth embodiment in which a first retracting operation and a second retracting operation are switched based on sensor detection information provided with the sensor 19b.

The operation of transporting the original sheet bundle P in the present embodiment will be described. First, as in the case described above,
The original sheet bundle P to be read is placed on the original set table 10.
The document sheet bundle P is set with its leading end abutting on the broken line position of the document stopper 25, and is further positioned in the width direction by the left and right side guides 11 of the document sheet bundle P. At this time, the original set detection filler 21 moves, the light shielding of the original set sensor 28 is released, the original set is detected, and an original set signal is transmitted to the main body control unit 111.

Next, in response to a paper feed command signal from the main body control unit 111 to the controller 100, FIGS.
Is performed.

In this document feeding operation, first, the setting of the document is detected (step S81), and if the document sheet is not set on the document set table 10, the current processing is terminated (step S81: no). If the original sheet is set on the original set table 10, the calling motor 101 is driven forward (step S82).

When the calling motor 101 rotates forward, the pickup roller 20 moves down from the upper stop position and moves to the upper surface of the original, and presses the original sheet bundle P with a predetermined pressure of its own weight (yes in step S83). ), The calling motor 101 is stopped (step S84).

Next, it is checked whether or not the position of the pickup roller 20 has passed the height corresponding to the lift amount Lb of the second cam surface 131b (step S85), and has reached the height corresponding to the lift amount Lb. If it is (YES in step S85), a predetermined flag setting process for setting a flag indicating that the pickup roller position has passed the intermediate retreat position b is executed (step S86).

When the pickup roller 20 is moved to the calling position, the number of driving pulses is changed according to the presence or absence of the intermediate retreat position b passage flag, as in the second embodiment.

Alternatively, similarly to the second embodiment, a separate sensor can be provided to eliminate the need to determine the passage flag.

Thereafter, after a lapse of a predetermined time, or if the determination result in step S85 is no, the process proceeds to step S85.
After 85, the paper feed motor 102 for driving the separation paper feed unit 2 and the registration unit 3 is driven to rotate forward (step S87),
The pickup roller 20 is fed and rotated, and the original sheet bundle P
The uppermost original sheet is fed from the uppermost position to the separation sheet feeder 2.

The document separated into one sheet by the action of the paper feed belt 23 and the separation roller 26 is further conveyed by the paper feed belt 23 and advances in the paper feed path 27. In this process, when the front end is detected by the abutting sensor 29 (yes in step S88), the abutting sensor 29 abuts on the registration roller 30 which has stopped further. Here, in order to hit the document by a predetermined amount, a hit count is started based on the number of drive pulses of the paper feed motor 102 (step S).
91). If the predetermined time has elapsed without the abutment sensor 29 being turned on in step S88, it is determined that the time is over (yes in step S89), and the process of the predetermined unreachable jam is executed (step S90).

When the hit count is started, then
It is checked whether or not the intermediate retreat position passage flag is set (step S92). If the flag is set (yes in step S92), the calling motor 101 is rotated in reverse (step S92).
93), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the original, and
0 is the lift amount L of the second cam surface 131b of the drive cam 131
It is determined whether or not a predetermined intermediate retreat position b corresponding to b has been reached (step S94). Then, the determination result is ye
If it is s, the calling motor 101 is stopped (step S95).

On the other hand, if the decision result in the step S66 is no, that is, if the document height is high and the intermediate retreat position passing flag is not set, then the calling motor 101 is rotated forward to ( Step S
96), the pickup roller 20 is retracted upward so as to be separated from the upper surface of the document, and the pickup roller 2
0 is the lift amount L of the first cam surface 131a of the drive cam 131
It is determined whether or not the retracted position (upper stop position) corresponding to a has been reached (step S97). If the result of the determination is yes, the calling motor 101 is stopped (step S98).

During this time, by feeding the original sheet only by the conveying force of the paper feed belt 23, the leading end of the original sheet enters the nip portion between the pair of upper and lower rollers of the registration roller 30, and the leading end alignment (correction of abutting skew) is performed. Done.

After the calling motor 101 stops, the original sheet is detected by the abutment sensor 29,
In the forward rotation of No. 2, it is transported by a predetermined distance (predetermined number of pulses). At this time, it is determined whether or not the abutment count amount is the predetermined number of pulses (step S99).
The paper feed motor 102 is stopped, and the paper feed belt 23 is stopped (step S101).

Next, the registration roller 30 is driven by the normal rotation of the reading motor 103, and the document sheet is conveyed in the direction of the reversing unit 4 (step S102). At least one of the image forming apparatus main body 1000 and the contact image sensor 61 is used. A predetermined reading operation is performed (step S103). Then, when the trailing end of the document sheet that has passed the image reading position is detected by the paper discharge sensor 70 (step S104), the next document feed signal is generated (step S105).

As described above, in this embodiment, the filler 12 for detecting that the pickup roller 20 has reached the intermediate retract position b lower than the uppermost retract position (upper stop position).
8b and a sensor 19b, and the elevating means 140 switches between the first evacuating operation and the second evacuating operation based on the intermediate evacuation height detection information. When the abutment height of the pickup roller 20 reaches a predetermined height, the retracting height of the pickup roller 20 can be switched at a preferable timing according to the height of the original sheet bundle, and the drop impact noise can be reduced. it can.

Further, at the time of sheet feeding after the pickup roller 20 reaches the intermediate retract position b, the pickup roller 2
The retracting height can be reduced by setting the descending start position of 0 as the intermediate retracting position b. In this case, the portion where the drive cam 131 abuts on the cam follower portion 133a is the first cam surface 1
31a from the second cam surface 131b to the second cam surface 131b.
From the first cam surface 131c to the third cam surface 131c.
By reciprocating between the first cam surface 31b and the third cam surface 131c, a quick copying operation or the like can be performed when necessary.

In each of the above-described embodiments, the pickup roller 20 comes into contact with the original sheet bundle P at a predetermined contact pressure by the downward urging force mainly due to its own weight. Since the contact pressure to P is about its own weight, regardless of the thickness of the sheet bundle,
A stable contact pressure suitable for friction feeding can be obtained.
Here, the downward biasing force mainly by its own weight means that the biasing force of the pickup roller 20 and its supporting portion due to its own weight is other auxiliary biasing force (for example, such as a torsion spring 141 having a small spring constant or the like). It is larger than a substantially constant urging force in the descending direction by the elastic member.

In addition, when there is no original sheet on the original set table 10,
The pickup roller 20 is retracted to the upper stop position, and when a sheet is placed on the document set table 10, at least the first time the pickup roller 2 moves from the upper stop position to a contact position with the document sheet bundle P.
Decrease 0. In this case, when the original sheet bundle P is placed on the original set table 10, the pickup roller 20 is always retracted at the upper stop position, and it is possible to handle a thick original. In addition, since the operation of lowering the pickup roller 20 from the upper stop position to the sheet bundle is performed at least once at the first time, if the sheet bundle is thin, the retracting height of the pickup roller 20 can be reduced.

Further, in the ADF 200, since the rotational power of the pickup roller 20 is obtained from the separation sheet feeding section 2,
The mechanism is simplified. Further, when the lifting timing of the pickup roller 20 is controlled by using the lifting / lowering means 140, the feeding time of the pickup roller 20 can be controlled.

In the image forming apparatus main body 1000 of each embodiment, when the start of copying or the like is instructed, the pickup roller 20 can be lowered to immediately start the separation and feeding of the original. The impact sound at the time of descending can be reduced. The image forming apparatus main body 1000 is a scanner (image reading device) that reads an image of a document conveyed to a predetermined document reading position by the ADF 200, generates image data representing the document image, and outputs the image data. Also in operation, the pickup roller 20 is lowered when a reading start command is issued, so that separation and feeding of the original sheet can be started immediately, and further, the impact noise when the pickup roller 20 is lowered can be reduced. Can be. Further, when the image forming apparatus main body 1000 is a facsimile machine, the pickup roller 20 is lowered when a transmission or recording output command is issued, so that separation and feeding of the original sheet can be started immediately. The impact sound at the time can be reduced.

[0170]

According to the present invention, the raising and lowering of the feeding member is stopped at the ascending position which is the upper stop position in the ascending and descending range of the feeding member, so that a thick sheet bundle can be fed. On the other hand, when the feeding member is lowered from its raised position, the lowering of the feeding member during the lowering is restricted, and the lowering speed after the restriction is reduced, so that the substantial lowering of the feeding member is performed. The impact sound can be reduced in the same manner as when the start position is lowered.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an automatic document feeder and an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the automatic document feeder and the image forming apparatus according to the first embodiment.

FIG. 3 is a block diagram illustrating a configuration of a contact image sensor according to the first embodiment.

FIG. 4 is an operation explanatory diagram showing an elevating operation of a pickup roller in the automatic document feeder of the first embodiment.

FIG. 5 is a perspective view of a lifting / lowering drive mechanism of a drive cam in the automatic document feeder according to the first embodiment.

FIG. 6 is a perspective view of a main part of a lifting unit in the automatic document feeder according to the first embodiment.

FIGS. 7A and 7B are diagrams showing a relationship between a paper feed belt and a pickup roller according to the first embodiment, wherein FIG. 7A is a perspective view of a lowered state in which the pickup roller has moved to a contact position side, and FIG. FIG. 4 is a perspective view of a retracted state moved to a position.

FIG. 8 is an exploded perspective view of the sheet feeding belt unit according to the first embodiment.

FIG. 9 is a partial side view showing the shape of the drive cam of the first embodiment.

FIG. 10 is a perspective view of first and second drive cam position detecting means in the automatic document feeder of the first embodiment.

FIG. 11 is a flowchart illustrating a sheet feeding operation according to the first embodiment.

FIG. 12 is a flowchart of the sheet feeding operation continued from FIG. 11;

FIG. 13 is a flowchart illustrating a sheet feeding operation according to the second embodiment.

FIG. 14 is a flowchart of the sheet feeding operation following FIG.

FIG. 15 is a flowchart illustrating a sheet feeding operation according to the third embodiment.

FIG. 16 is a flowchart of the sheet feeding operation continued from FIG. 15;

FIG. 17 is a flowchart illustrating a sheet feeding operation according to a fourth embodiment.

FIG. 18 is a flowchart of the sheet feeding operation continued from FIG. 17;

[Explanation of symbols]

10 Document Set Table (Document Placement Table) 19 Home Position Sensor (First Cam Position Detector) 19a, 19b Sensor (First Cam Position Detector, Second Cam Position Detector) 20 Pickup Roller (Feeding Member) 21 Document Set detection filler 23 Paper feed belt 25 Document stopper 26 Separation roller 30 Registration roller 40 Registration sensor 43 Reading / conveying roller 54 Contact glass 61 Close contact image sensor 70 Discharge sensor 80 Reverse switching claw 81 Reverse discharge roller pair 83 Switchback path 90 Discharge Paper stacker 100 Controller 101 Calling motor 102 Feeding motor 108 Operation unit 111 Main unit control unit 120 Elevating drive mechanism 122 Toothed transmission belt 123 Toothed wheel 128a Filler (detected member) 128a, 128b Filler -(Detected member) 131 Drive cam 131a First cam surface 131b Second cam surface 131c Third cam surface 133 Pickup drive member (drive transmission member) 133a Cam follower lever portion 133b Lifting drive lever portion 134 Feeding belt drive shaft 135 Swinging member 135a Swing support shaft 135a Swing support shaft 135b One end 135c Other end 138 Bracket 140 Elevating means 200 ADF 1000 Image forming apparatus main body

Claims (19)

[Claims] A feeder for loading a sheet bundle placed on the mounting table into contact with an upper portion of the sheet bundle placed on the mounting table by a predetermined urging force to recall the upper sheet of the sheet bundle to a separation position; A feeding member, separating means for separating the uppermost sheet of the sheets called to the separation position by the feeding member from a lower sheet, and raising the feeding member so as to be separated from the uppermost sheet. Lifting means for holding the sheet at the ascending position, releasing the holding, allowing the sheet feeding member to descend by the urging force, and bringing the sheet feeding member up and down by making contact with the upper portion of the sheet bundle. In the sheet bundle separating and feeding device, the lifting / lowering means can execute a descent restriction operation of restricting descent of the feeding member during descent and reducing a descent speed of the feeding member after the restriction. Separation of sheet bundle Feeding device. 2. The lowering operation of the elevating means, wherein the lowering speed of the feeding member is reduced below the raising position while allowing the lowering of the feeding member. 2. The sheet bundle separating and feeding device according to 1. 3. The separation and feeding of a sheet bundle according to claim 1, wherein the lowering operation of the raising and lowering means is an operation of temporarily stopping the lowering of the feeding member below the raising position. apparatus. 4. The apparatus according to claim 1, wherein the elevating means is located at a position higher than a position at which the feeding member contacts the sheet bundle on the mounting table, and an intermediate stop position for temporarily stopping the lowering of the feeding member. The sheet feeding and separating apparatus according to claim 3, wherein the feeding member is dropped from any one of the lower positions. 5. A feeding table, on which a sheet bundle is placed, and an upper portion of the sheet bundle placed on the placing table, which is brought into contact with a predetermined urging force, to feed the upper sheet of the sheet bundle to a separation position. A feeding member, separating means for separating the uppermost sheet of the sheets called to the separation position by the feeding member from a lower sheet, a driving cam for driving the feeding member up and down, and A drive transmission member for transmitting the drive force of the drive member to the feeding member;
And raising the feeding member so as to be separated from the uppermost sheet and holding the feeding member at a raised position, and releasing the holding to allow the feeding member to be lowered by the urging force, thereby allowing the upper portion of the sheet bundle And a lifting unit that raises and lowers the feeding member by contacting the feeding member with the drive transmission member. The lifting / lowering unit applies a part of the cam surface of the drive cam to the drive transmission member. Contacting the feed member at the raised position, releasing a part of the cam surface of the drive cam from the drive transmission member to release the holding of the feed member at the raised position. A sheet bundle, wherein the lowering of the feeding member is restricted during the lowering of the remaining portion of the cam surface of the driving cam via the driving transmission member, and the lowering speed of the feeding member after the restriction is reduced. Separation feeding device. 6. The separation and feeding of a sheet bundle according to claim 5, wherein when the driving cam releases the holding of the feeding member at the raised position, the rotation of the driving cam is constant. Feeder. 7. The driving cam has a first cam surface having a maximum lift, a second cam surface having an intermediate lift smaller than the maximum lift, and a third cam surface having a minimum lift smaller than the intermediate lift.
A cam surface, and the elevating means rotates the drive cam forward and reverse to
The cam surface and the third cam surface are alternately opposed to the drive transmission member, and the feeding member can be moved up and down in a predetermined range below the ascending position. Sheet bundle separation and feeding device. 8. The driving cam has a first cam surface having a maximum lift, a second cam surface having an intermediate lift smaller than the maximum lift, and a third cam surface having a minimum lift smaller than the intermediate lift.
A first cam position detecting means for detecting that the first cam surface of the drive cam has contacted the drive transmission member, and a second cam surface of the drive cam to the drive transmission member. The sheet bundle separation and feeding device according to claim 5, further comprising a second cam position detecting unit that detects the contact. 9. A sheet bundle separating and feeding device according to claim 1, wherein the weight of said feeding member acts as said urging force. 10. A sheet according to claim 1, wherein said feeding member is retracted to said raised position irrespective of the height of the sheet bundle on said mounting table. Bundle separation feeding device. 11. The drive cam has a first cam surface having a maximum lift, a second cam surface having an intermediate lift smaller than the maximum lift, and a third cam surface having a minimum lift smaller than the intermediate lift. The elevating means rotates the driving cam only in one direction, so that the first cam surface, the second cam surface, and the third
The sheet feeding and separating apparatus according to claim 10, wherein a cam surface is sequentially opposed to the drive transmission member. 12. The apparatus according to claim 12, wherein said elevating means retracts said feeding member to said raised position when there is no sheet on said mounting table, and at least one time when said sheet is mounted on said mounting table. The sheet feeding / separating apparatus according to any one of claims 1 to 9, wherein the feeding member is lowered from the rising position to a contact position with the sheet bundle. 13. A first retracting operation for retracting the feeding member to the raised position in accordance with a height of the sheet bundle on the mounting table, wherein the lifting means moves the feeding member to the raised position. Performing one of a second retreat operation for retreating to a lower intermediate stop position, and adjusting a retreat height of the feeding member from the uppermost sheet to a certain height or less. A sheet feeding / separating apparatus according to claim 1. 14. A sheet height detecting means for detecting a height of a sheet bundle on a mounting table, wherein said elevating means performs said first retreat operation based on detection information of said sheet height detecting means. 14. The sheet feeding / separating apparatus according to claim 13, wherein the apparatus switches between the first and second retracting operations. 15. An intermediate retreat height detecting means for detecting that the feeding member has reached an intermediate retreat position lower than the raising position, wherein the elevating means detects the intermediate retreat height detecting means based on detection information of the intermediate retreat height detecting means. 14. The sheet bundle separation and feeding device according to claim 13, wherein the first retreat operation and the second retreat operation are switched based on the first retreat operation. 16. A sheet height input means for setting and inputting whether or not the number of stacked sheets on the mounting table is equal to or less than a predetermined number, wherein when a sheet is mounted on the mounting table, 14. The sheet bundle separation and feeding device according to claim 13, wherein the raising and lowering means sets a lowering start position of the feeding member based on input information of the sheet height inputting means. 17. An automatic document feeder provided with the sheet bundle separating and feeding device according to claim 1. 18. An image forming apparatus comprising the sheet bundle separating and feeding device according to claim 1. 19. An image reading apparatus comprising the sheet bundle separating and feeding device according to claim 1.