JPH10329963A - Sheet conveying device, image reading device provided with it, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform the placement of a sheet document to a document tray and processing for a jam and facilitate replacement of a separating unit. SOLUTION: In the case of stacking of a document, replacement of a feeding roller or a separating belt, and processing for a document jam, a pickup roller 6 is retracted from a document tray 5 by means of a supporting arm 90. In this way, a document can be easily stacked onto the document tray 5, and at the same time, a jam can be processed with ease. In this way, an accident, in which the pickup roller 6 is damaged, for example, can be prevented. On the other hand, replacement of the feeding roller or the separating belt can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus such as an automatic document conveying apparatus for reading an original by a flow reading method, and a sheet conveying apparatus used in an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile. The present invention relates to an image reading device and an image forming device.

[0002]

2. Description of the Related Art In the case of an automatic document feeder of an upper separating roller feeding type as a conventional sheet feeder, a document placed on a document tray is picked up by a pickup roller.
In general, the sheet is fed one by one from the top.

In this case, the pickup roller performs a sheet feeding operation as follows.

That is, when the pick-up roller enters a paper feeding operation, the pickup roller is lowered from a standby position above the original to a paper feeding position in contact with the uppermost original. Then, the pickup roller is supplied with a driving force and rotates to convey the uppermost document into the image forming apparatus main body.

When the leading edge of the original reaches the pair of conveying rollers downstream of the pickup roller in the conveying direction, the pickup roller rises so as to be separated from the upper surface of the original, returns to the standby position again, and returns to the next standby position. I was preparing for paper feeding.

[0006]

However, in the above-mentioned conventional automatic document feeder, the pick-up roller disposed on the document tray contacts the document on the document tray when the document is fed, and the pickup roller is placed in the standby state and during standby. When loading originals, the pick-up roller hinders the work of loading originals or exchanging originals because it is arranged so that it can be lifted and lowered so as to be separated from the originals on the original tray at the standby position. There was a problem that work was very difficult.

In addition, there is a problem that an accident such as accidental contact with the pickup roller and damage during the jam clearance occurs, and there is a problem that the pickup roller must be replaced more than necessary.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and makes it possible to easily carry out stacking of sheets on a sheet stacking means and to clear a jam, and to easily exchange a separation unit. It is an object of the present invention to provide a sheet conveying apparatus capable of performing the above-mentioned operations, an image reading apparatus and an image forming apparatus including the same.

[0009]

According to another aspect of the present invention, there is provided a sheet conveying apparatus, comprising: a sheet stacking unit for stacking sheets; and a sheet stacked on the sheet stacking unit. Sheet feeding means for feeding the sheet feeding section toward the downstream separating portion, and turning means for turning the sheet feeding means to a feeding position and a standby position,
The sheet feeding means and the turning means are supported and the sheet feeding means and the turning means are stacked on the sheet stacking means at a retreat position where sheets can be stacked on the sheet stacking means. Rotatable moving means for selectively moving the sheet to a feeding position for transporting the sheet or to a replaceable replacement position of the separation unit.

According to the second aspect of the present invention, the moving means detects that the rear end of the sheet conveyed from the sheet stacking means to the separation unit has passed the sheet feeding means. It supports passage detection means.

According to a third aspect of the present invention, the moving means includes:
There is provided a driving means for selectively rotating to any of the retracted position, the feeding position and the exchange position.

According to a fourth aspect of the present invention, there is provided a position detecting means for detecting whether the moving means is located at the retracted position, the feeding position or the replacement position, and the moving means is provided by the position detecting means. And control means for stopping the driving means when it is detected that the driving means is located at any of the retreat position, the feeding position and the exchange position.

According to a fifth aspect of the present invention, there is provided the sheet transporting device according to any one of the first to fourth aspects, and document reading means for reading a sheet document fed from the sheet transporting device.

According to a sixth aspect of the present invention, there is provided a sheet transport apparatus according to any one of the first to fourth aspects, a document reading means for reading a sheet document fed from the sheet transport apparatus, and the document reading means. Image forming means for forming an image on a recording sheet based on image information read by the means.

[Operation] Based on the above configuration, when stacking sheets on the sheet stacking means, processing a jammed sheet, or replacing the separation unit, the moving means is rotated to load the sheets. The sheet feeding means is retracted from the means. Thus, sheets can be easily stacked on the sheet stacking means, and jam processing can be easily performed. This also prevents accidents such as damaging the sheet feeding means. In addition, the parts of the separation unit can be easily replaced.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. <First Embodiment> FIG. 1 is a front sectional view showing an image reading apparatus to which the present invention can be applied, FIGS. 2A and 2B are configuration diagrams for explaining the operation of lifting and lowering a document tray, and FIG. 4A and 4B are conceptual diagrams illustrating the operation of the paper surface height sensor.

In FIG. 1, 1 is an image reading device, 2 is a document reading section for reading a running sheet document S by a flow reading method, and 3 is an automatic document feeder (hereinafter, referred to as a document feeding device) for feeding the sheet document S to the document reading section 2. Reference numeral 4 denotes an image forming unit.

The image reading device 1 and the image forming means 4
13 may be separate as shown in FIG. 13, but may be integrated.

The ADF 3 includes a document tray 5 as a sheet stacking unit capable of stacking a plurality of sheet documents S, a pickup roller 6 as a sheet feeding unit for taking out the sheet documents S one by one, a multi-fed sheet document. S, a separation unit 7 for separating the sheet S, a pull-out roller pair 8 for conveying the sheet document S to the document reading unit 2, and a pair of conveyance rollers 9, 10, 11
And a pair of transport rollers 13, 14, and 15 for transporting the read sheet S to the discharge tray 12.

Here, the ADF is fixedly supported by the main body frame 40 and detects the standby position of the document tray 5 and a lower limit sensor 31 which always keeps the height position of the uppermost sheet document S at the time of paper feeding at a constant height. And a paper height sensor 32 for keeping the paper height. Further, on the document tray 5, a rear-end passage detection sensor 60 is provided upstream of the pickup roller 6 in the conveyance direction of the sheet document S as rear-end passage detection means for detecting that the rear end of the sheet document S has passed. Have been. The detailed description of these sensors 31, 32, 60 will be described later.

The image reading apparatus 1 includes a first mirror base 16 as a scanning optical unit, a second mirror base 17, a lens 18, a CCD sensor 19 as a reading element, and an image processing unit (not shown). It consists of.

The first mirror table 16 is provided with an exposure lamp 20 for irradiating the surface of the sheet document S, a reflector 21 and a first mirror 22 for changing the direction of the reflected light of the irradiated sheet document S. I have. The second mirror base 17 is provided with a second mirror 23 and a third mirror 2S that further change the angle of the reflected light whose angle has been changed by the first mirror 22 and guide the reflected light to the CCD sensor 19 through the lens 18. ing. The first mirror base 16 is fixed substantially below the contact glass 26 and constitutes the document reading unit 2.

Next, the configuration of the image forming means will be described with reference to FIG.

In FIG. 13, reference numeral 25 denotes an upper cassette.
The recording sheets in the upper cassette 25 are separated and fed one by one by the action of the separation claw and the feeding roller 27u, and are guided to the registration rollers. Reference numeral 29 denotes a lower cassette. The recording sheets in the lower cassette 29 are separated and fed one by one by the action of the separation claw and the feeding roller 27d, and are guided to the registration roller.

Reference numeral 111 denotes a laser modulator (laser scanner) to which a processing signal from the image reading device 1 is input, for example.
112 is a photosensitive drum, 113 is an image writing optical system, 1
Reference numeral 14 denotes a developing device, 115 denotes a transfer charger, and 116 denotes a separation charger, and these constitute an image forming unit.

Reference numeral 117 denotes a conveyance belt for conveying the recording sheet on which an image has been formed, 118 denotes a fixing device, and 119 denotes a discharge roller. The recording sheet on which the image has been formed is fed to a discharge roller 11.
9 to the sorter.

The image forming means 4 functions as a copying machine when a processing signal of the image processing section is input to the laser modulation section 111, and functions as a facsimile when a facsimile transmission signal is input. If a signal is input, it functions as a printer. Conversely, if the processing signal of the image processing unit is transmitted to another facsimile, it functions as a facsimile.

Next, the basic operation of the image reading apparatus 1 according to the present invention will be described.

When the operator places the sheet originals S on the original tray 5 and instructs the start of image reading by an operation unit (not shown), the exposure lamp 20 is turned on to start the sheet feeding operation.

As a result, the document tray 5 retracted to the standby position starts to be lifted by the driving means described later, and continues to be lifted until the uppermost sheet document S is detected by the sheet height sensor 32.

Then, the sheet document S on the document tray 5 is sent out by the pickup roller 6, and unnecessary sheet documents S other than the topmost sheet document S are separated by the separation unit 7. Thereafter, the pull-out roller 8, the transport rollers 9, 10,
The sheet document S is conveyed to the image reading unit 2 by 11.

The sheet document S being conveyed is irradiated with light from an exposure lamp 20 and the reflected light is applied to a first mirror 2.
2, guided by the second mirror 23 and the third mirror 24 to the lens 18 and imaged on the CCD sensor 19. Then, the sheet document S is transported further downstream by the transport rollers 13, 14 and 15, and is discharged onto the discharge tray 12. This series of operations is performed when the sheet document S is placed on the document tray 5.
This operation is repeated until all the sheets S have been exhausted from the top. When all the sheets S have been exhausted, the document tray 5 is lowered to the standby position and the process is completed, and the exposure lamp 20 turns off.

Next, the structure of the horizontal movement of the document tray 5 will be described in detail with reference to FIGS.

FIGS. 2A and 2B are views of the document tray viewed from the downstream side in the document conveying direction. FIG. 2A is a side view showing the document tray at the standby position, and FIG. 2B is a diagram showing the document tray at the sheet feeding position. FIG. 3 is a side view, FIG. 3 is a bottom view showing the document tray, FIG. 4 is a view for explaining the operation of the paper height sensor, (a) is an operation conceptual diagram when the document tray is in a standby position, FIG. 3B is an operation conceptual diagram in a case where the document tray is in a paper feed position.

An operator places the sheet document S on the document tray 5 and then uses a pair of left and right side guides 33 to prevent the sheet document S from being skewed during feeding. To match. Then, when an image reading start is instructed by an operation unit (not shown), an image reading start signal is input to the CPU 50 as control means. Then, a control signal from the CPU 50 is input to a lifter motor 34 as a driving unit, and rotates the driving gear 35 in a counterclockwise direction and rotates an idler gear 37 meshing with the driving gear 35 in a clockwise direction.

Then, the sector gear 36 and the arm 38 integrally attached to the sector gear 36 are connected to a shaft 36a.
, And is rotated in the direction of the arrow X by the drive gear 35 and the idler gear 37. As a result, the document tray 5 is raised via the support rollers 39 rotatably attached to the arm 38.

In the present embodiment, the driving force for raising and lowering the document tray 5 has been described as a configuration in which the driving force from the lifter motor 34 is transmitted by a gear. However, the driving force may be transmitted by a belt. Similar effects can be obtained.

Next, the stop control of the raising operation of the document tray 5 will be described with reference to FIG.

The paper height sensor 32 includes a light transmission type photo sensor 32a and a flag 63b for turning on and off the light transmission type photo sensor 32a. The flag 63b is formed on a part of a holder 63 of a rear end passage detection sensor 60 described later, and is supported so as to be able to move up and down with respect to the photo sensor 32a.

When the document tray 5 is retracted to the standby position, as shown in FIG.
Is lowered, and the photo sensor 32a recognizes that the photo sensor 32a is in an off state by transmitting light. Next, when an instruction to start image reading is given, the lifter motor 34 is driven by a control circuit (not shown), and the original tray 5 is
Is raised, and the flag 63b is determined by the uppermost sheet document S.
Is pushed up.

When the sheet document S reaches the sheet feeding position, a flag 63b is interposed between the photo sensors 32a as shown in FIG. 4B, and the photo sensor 32a is turned on to block light. That is, the rotation of the lifter motor 34 is stopped by a control circuit (not shown), and the state shown in FIG.

Thereafter, when the uppermost sheet document S is sequentially fed, the height of the uppermost sheet document S gradually decreases, and accordingly the flag 63 is relatively reduced.
b will also decrease. For this reason, the photo sensor 32a
Is turned off by transmitting light, so that the lifter motor 34 is driven again until the photo sensor 32a is turned on. When the photo sensor 32a is turned on with the flag 63b interposed between the photo sensors 32a,
The rotation of the lifter motor 34 is stopped. Hereinafter, such a series of operations is repeated until there is no sheet document S.

Next, control for stopping the lowering operation of the document tray 5 will be described.

As shown in FIG. 2B, the lower limit sensor 31 includes a main body 31a, an arm 31b, and a switch 3.
1c, when the document tray 5 is in the paper feeding state, the arm 31b is separated from the main body 31a and the switch 31c as shown in FIG. When it is detected by the recycle lever (not shown) or the like that the sheet document S has run out on the document tray 5,
As shown in FIG. 2A, the lifter motor 34 rotates in the reverse direction, the document tray 5 is lowered, and the document tray 5 is
By pressing 1b, the switch unit 31c is turned on and the rotation of the lifter motor 34 is stopped.

Further, a guide configuration at the time of the elevating operation of the document tray 5 will be described with reference to FIG.

The document tray 5 is transported (in the direction of the arrow) of the sheet document S so as to be guided by the body frame 40.
Are supported rotatably on both sides of the roller. The two abutting rollers 41 on one side receive the pressing force of the compression spring 42 and are in contact with the main body frame 40. For this reason, the document tray 5 is positioned by the main body frame 40 without play in the direction perpendicular to the direction in which the sheet document S is conveyed. On the other hand, in the main body frame 40,
A guide portion 40a is formed to regulate the operation range of the document tray 5 in the elevating direction and guide the elevating operation, and the abutting roller 41 is fitted into the guide portion 40a. For this reason, the document tray 5 is positioned with respect to the transport direction of the sheet document S (the direction of the arrow in FIG. 3). As a result, the document placing surface of the document tray 5 moves up and down along the body frame 40 in the horizontal direction without play.

Next, the separating section 7 will be described in detail with reference to FIGS.

First, based on FIG. 5 and FIG.
Will be described.

The front plate 121, the rear plate 122, and the lower paper guide 128 are fixed by screws, respectively, and constitute a frame of the separation unit 7.

The feed roller shaft 117a of the feed roller 117
Is rotatably supported between a front side plate 121 and a rear side plate 122 via a bearing (not shown) as shown in FIG.
The separation belt 118 is stretched around a belt driving roller 118b integrally attached to the belt driving shaft 118a and a belt driven roller 118c rotatably held on the belt driven shaft 118d. That is, the belt driven shaft 118d is fixed to the belt side plate 126 with screws. Further, the belt driving shaft 118a is
Are rotatably supported via bearings (not shown). The separation belt 118 enters the feed roller 117 with the amount of penetration F
It is arranged on the front side plate 121 and the rear side plate 122 so as to bite in.

On the other hand, a roller gear 123 is integrally attached to one end (the front plate 121 side) of the feeding roller shaft 117a, and a belt gear 125 is attached to one end (the front plate 121 side) of the belt drive shaft 118a. And an idler gear 124 is rotatably supported between the roller gear 123 and the belt gear 125.

The driving force from the ADF 3 is input to the belt gear 125 and transmitted to the roller gear 123 via the idler gear 124. As a result, the separation belt 118 is rotated in the direction indicated by the arrow A, and the feed roller 117 is also rotated in the direction indicated by the arrow A. Therefore, the sheet document S is separated one by one and fed and conveyed in the direction of arrow B.

As shown in FIG. 5, the front plate 121 has a round hole 121a and a long hole 122a, and the rear plate 122 has a round hole 122a and a long hole (not shown). Has been established. A fixed shaft 133 is fixed to one frame 131 of the ADF 3 as shown in FIG. 6, and a fixed support unit 13 is fixed to the other frame 131.
0 is screwed.

Further, the fixed support unit 130
A cover 135 is fixed to the case 134 with screws, and a slide support shaft 136 is slidably provided through the case 134 and the cover 135. Also,
A handle 137 is fixed to the slide support shaft 136 by caulking.

A pressure spring 138 for pressing the slide support shaft 136 in the direction of the separating portion 7 is interposed between the lid 135 and the handle 137.

Thus, the round hole 121a and the long round hole 12
1b, the slide support shaft 136 is inserted into the round hole 122a.
The fixed shaft 133 is inserted into the oval hole (not shown). The separation unit 7 is supported in a state where the separation spring 7 is pressed by the slide support shaft 136 in the direction of arrow E shown in FIG.

Further, the rotation drive section 140 of the separation section 7 will be described with reference to FIG.

The rotation drive section 140 has a separation drive motor 141 using a stepping motor which has almost no time lag in terms of electric control, and a drive gear 142 is integrally attached to a shaft 141a. The drive gear 142 meshes with the swing gear 143,
The gear holder 144 is rotatably supported via a bearing (not shown). Further, the swing gear 143 is driven by the swing gear shaft 145 via a bearing (not shown).
4 is rotatably supported.

Further, the tension spring 146 has one end locked to the gear holder 144 and the other end locked to the frame 131. As a result, the swing gear 143 rotates upward around the drive motor shaft 141a and meshes with the belt gear 125. When the swing gear 143 and the belt gear 125 mesh with each other, the abutting portion 125b on the rotation shaft of the belt gear 125 and the swing gear 1
Abutting portion 143 provided on the oscillating gear shaft 145
b, the gear portions 125a and 143a
Can be engaged while maintaining a regular center distance, and the driving force is transmitted accurately.

Next, the drive control of the separation unit 7 will be described.

The separation unit 7 stops driving when the rear end of the sheet document S is still nipped by the separation unit 7 in order to open a predetermined space between the sheet documents S. Then, the subsequent transport of the sheet document S is performed by the pull-out roller pair 8 and the transport roller pairs 9, 10, and 11 on the downstream side.

The reason is that if the separation unit 7 is continuously driven, if two or more sheet documents S are conveyed to the separation unit 7 by the pickup roller 6, the first sheet document S is removed from the separation unit 7. This is to prevent the second sheet document S from being conveyed without opening the sheet interval.

For this reason, the passage of the trailing edge of the sheet document S is detected by the trailing edge detection sensor 60 (see FIG. 1) (a specific detection method will be described later in detail). The separation drive motor 141 is controlled so as to stop the conveyance when the rear end of the sheet document S is nipped by the separation unit 7 by about 10 mm before the rear end of the sheet S.

The roller gear 123 has a one-way clutch. Even if the sheet S is conveyed so as to be pulled out by only the pulling-out roller pair 8, the feeding roller 117 is moved in the direction of arrow D shown in FIG. You can go around.

Next, based on FIGS. 8 to 12, the structure of the pickup roller 6 and the supporting arm 90 as a moving means around the pickup roller 6 and its control operation, the procedure for loading the sheet S on the document tray 5, the separation section The roller replacement work procedure of No. 7 will be described in detail.

First, FIGS. 8A and 8B show the configuration of the rear end passage detecting sensor 60 in detail, wherein FIG. 8A is a sectional view and FIG. 8B is a side view. The rotating roller 61 has a core 61a, a roller 61b made of a rubber material, a disk 61c, and holes 61d formed at equal intervals in the disk 61c at equal intervals. It is rotatably supported by a shaft 62.

A light transmission type photosensor 64 for detecting the rotation of the disk 61c is attached to the holder 63.
The light transmitted through the hole 63a of the holder 63 is detected. The rear-end passage detection sensor 60 is rotatably supported by the paper feed frame 91 of the support arm 90. I'm on

When the rotating roller 61 rotates in accordance with the operation of transporting the sheet document S, the disk 61 c also rotates together with the rotation of the rotating roller 61.
Alternately outputs a Hi / Low signal according to the hole 61d.
Output to U50. Here, 63b is the above-mentioned flag part which has a shape protruding from the holder 63.

FIG. 9 is a perspective view showing a drive configuration of the up-down operation during the sheet feeding operation sequence of the pickup roller 6.

The arm 72 has an arrow L
The pickup roller 6 is rotatably attached to the tip of the arm 72. Further, the pickup roller 6 is attached to a drive belt 74 stretched between a pulley of the shaft 73 and a pulley attached to the shaft of the pickup roller 6, and attached to a pulley of the shaft 73 and a shaft of a paper feed drive motor 76. The driving force of the paper feed drive motor 76 is transmitted by the drive belt 75 stretched between the pulley and the pulley.

Further, the rotation support lever 77 is supported so as to be rotatable about a shaft 78 in a direction indicated by an arrow N, and the rotation of the rotation support lever 77 about the shaft 78 causes the arm 72 to rotate. Push up part G. Therefore, the rotation support lever 77 is rotatably supported by the vertical drive motor 80 via a drive belt 79 stretched between the shaft 78 and the vertical drive motor 80.

With the above-described configuration, the rotation support lever 77 pushes up the arm 72 by the counterclockwise rotation of the vertical drive motor 80 to rotate the pickup roller 6 to the standby position separated from the sheet document S. The clockwise rotation of 80 causes the rotation support lever 77 to move the arm 7
Then, the pickup roller 6 is rotated to a sheet feeding position where the sheet 2 is brought into contact with the sheet document S by lowering the sheet feeding roller 2.

The arm 72, shaft 73, drive belt 74, drive belt 75, paper feed drive motor 76,
A rotation support lever 77, a shaft 78, a drive belt 79,
The vertical drive motor 80 constitutes a rotating means.

When the pickup roller 6 is at the sheet feeding position, the pickup roller 6 is rotated by driving the sheet feeding drive motor 76, and the uppermost sheet document S is conveyed toward the separation section 7. In this case, the rear end passage detection sensor 60 is located upstream of the pickup roller 6 in the transport direction of the sheet document S, and in order to prevent skew of the sheet document S being transported due to the load of the rotating roller 61, Are provided substantially at the center in the vertical direction.

FIG. 10 shows the control of the up / down operation of the pickup roller 6.
5 is a graph showing the output signal of FIG.

That is, the output signal of the trailing end passage detection sensor 60 indicates that the sheet roller S is rotated by the rotation roller 61 until the time T ₁ during which the sheet document S is being conveyed by the separation section 7 and the pull-out roller 8.
Rotate and the conveyance of the sheet document S is detected by the photo sensor 64, so that Hi / Low is repeatedly output at equal intervals. The output signal of the trailing edge passage detection sensor 60 from the time T ₁ to time T _4, to which is constant, can detect that the sheet document S passes at time T _1.

As a result, a rotation command is output from the CPU 50 to the vertical drive motor 80 at a time T ₂ after a predetermined time from the time T ₁ , and the pickup roller 6 at the standby position moves toward the paper feed position by the rotation of the vertical drive motor 80. It begins to drop, in contact with the sheet document S at time T _3.

[0078] The sheet document S until the time T ₃ to the rear end passes the pickup roller 6 is further transported by the separating unit 7 and the pull-up roller 8, the pickup roller 6 is in contact with the sheet document S being transported Never. Further, at time T ₄ after a predetermined time, the output rotation command from CPU50 in the sheet feeding drive motor 76, and the pickup roller 6 is rotated, for conveying the sheet document S, the output signal of the trailing edge passage detecting sensor 60 Is Hi /
Low is repeated at equal intervals.

Then, the time T _{5 when} the leading edge of the sheet document S reaches the paper detection sensor (not shown) downstream of the separation unit 7.
In the rotation command to the vertical drive motor 80 from the CPU50 is output, the pickup roller 6 was in feeding position starts to rise toward the standby position, returning to the standby position at time T _6, the next feeding operation Will be prepared. The rotation driving of the paper feed drive motor 76, the pickup roller 6 is stopped at time T ₆ was returned to the standby position.

Next, the sequence of the entire operation of the support arm 90 will be described.

As shown in FIG. 11, the support arm 90 has a paper feed frame 91 which supports the pickup roller 6 and the rear end passage detection sensor 60 so as to be vertically movable, and a main body which rotates the paper feed frame 91. A frame rotating gear 92 rotatably supported by the frame 40, a driving gear 94 for rotating the sheet feeding frame 91 around the frame rotating gear 92, and a movement as a driving means for rotating the driving gear 94 A motor 93 is provided, and the rotation of the moving motor 93 is controlled by the CPU 50.

Support arm 9 such as pickup roller 6
Reference numeral 0 indicates that the document tray 5 has been retracted to a retracted position above the loading surface of the document tray 5 as shown in FIG.
When the sheet document S is placed on the document tray 5 from above and the reading of the document is supported by an operation unit (not shown),
The movement motor 93 is rotationally driven based on a command from the PU 50, and the support arm 90 moves to the position shown in FIG.

In the paper feeding state, as described above, the pickup roller 6 comes in contact with the upper surface of the sheet document S (the solid line position in FIG. 11A) and the standby position (FIG. 11A ) (Dotted line position). Then, when all the sheet documents S are exhausted from the document tray 5, the support arm 90 returns to the retracted position shown in FIG. 11B again, and prepares for loading of the next sheet document S.

Similarly, when the sheet document S is jammed by the support arm 90 for some reason during the paper feeding operation,
The support arm 90 returns to the retracted position in FIG. Therefore, the operator performs a process of removing the jammed sheet document S from the support arm 90.

On the other hand, the separation section 7 needs to be replaced when the surfaces of the feeding roller 117 and the separation belt 118 are worn due to durability and the original separation and feeding performance cannot be exhibited. In such a case, the separation / exchange mode of the operation unit (not shown) is selected, the moving motor 93 is driven, and the support arm 90 is moved to the position shown in FIG. Thereby, the exterior cover (not shown) is opened, and the above-mentioned handle 137 is slid against the spring force of the pressure spring 138 to thereby fix the separating portion 7 fixed by the slide support shaft 136.
Comes off, and it is possible to easily replace it from above.

[0086] The support arm 90 is shown in FIG.
It is configured to be held in the states of (b) and (c). The configuration will be described in detail with reference to FIG.

The drive gear 94 has a gear portion 94a and a flag portion 94b. Around the flag portion 94b, the support arm 90 is provided with the replacement position of the separation unit 7, the retreat position of the pickup roller 6, and the pickup roller 6
The three sensors 98a, 98b, 98c are disposed as position detecting means for reliably positioning the sheet feeding position.

In order to position the drive gear 94 at a predetermined position, the lock lever 95 includes a claw 95a that engages with the gear 94a, and a rotation center 9 that rotatably supports the base end.
5b, and a lever portion 95c for connecting the claw portion 95a and the rotation center portion 95b. A claw portion 95a is provided between one side of the lever portion 95c and the main body frame 40 by a gear portion 94.
A solenoid 97 for extending a spring 96 to be engaged with the gear portion 94a and detaching the claw portion 95a from the gear portion 94a is attached to the other side of the lever portion 95c.

Therefore, the support arm 90 is rotated around the frame rotation gear 92 by the rotation of the moving motor 93, and the flag portion 94b and the sensors 98a, 98b, 98
The lock lever 95 meshes with the drive gear 94 and is held at a predetermined position so that the lock lever 95 is accurately stopped at each position by means of (c).

When the support arm 90 is moved to another position, the lock 97 and the drive gear 94 are disengaged by the solenoid 97 based on a control signal from the CPU 50. Then, the frame rotating gear 92 is set in a rotatable state, and is rotated to another position by the rotational drive of the moving motor 93 to hold the lock lever 95 and the driving gear 94 at a predetermined position.

As described above, the pickup roller 6 and the support arm 90 are configured to be retracted from above the original tray 5 when the originals are loaded other than the sheet feeding operation or when the jam is cleared, so that the sheet can be moved relative to the original tray 5. Document S
Can be easily placed, and the jam removal operation can be performed greatly easily.

Since the support arm 90 can be retracted to the replacement position in the apparatus main body when the feeding roller 117 and the separation belt 118 of the separation unit 7 are replaced, the work of replacement of the separation unit 7 is performed. Efficiency has also improved.

In the above embodiment, the image reading apparatus having the automatic document feeder has been described.
Of course, the same can be applied to an image forming apparatus having a configuration in which the pickup roller moves to the standby position.

[0094]

As described above, according to the present invention,
When stacking sheets, processing a jammed sheet, or replacing the separation unit, the moving unit is rotated to retract the sheet feeding unit from the sheet stacking unit, so that the sheet Sheets can be easily stacked on the stacking means, and jam clearance can be easily performed. This can prevent an accident such as damaging the sheet feeding means.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing an image reading apparatus according to the present invention.

FIGS. 2A and 2B are diagrams for explaining an operation of raising and lowering a document tray according to the automatic document feeder of the present invention, wherein FIG. 2A is a configuration diagram illustrating a document tray at a standby position, and FIG. It is a block diagram.

FIG. 3 is a bottom view showing a document tray according to the present invention.

FIG. 4 is a diagram for explaining the operation of the paper height sensor;
(A) is an operation conceptual diagram showing a flag in a state of a standby position,
(B) is an operation conceptual diagram showing a flag of a state of a sheet feeding position.

FIG. 5 is a perspective view of the separating portion according to the present invention as viewed from below.

FIG. 6 is a front cross-sectional view of a separation unit according to the third embodiment.

FIG. 7 is a perspective view showing a drive unit for driving the separation unit according to the third embodiment.

8A and 8B show a configuration of a rear end passage detection sensor of the present invention, wherein FIG. 8A is a sectional view and FIG. 8B is a side view.

FIG. 9 is a perspective view illustrating a driving configuration of a pickup roller in a sheet feeding operation sequence.

FIG. 10 is a conceptual graph showing an output signal of a rear end passage detection sensor and a position of a pickup roller according to the present invention.

FIG. 11 shows a support arm according to the present invention, wherein (a)
FIG. 4B is a diagram illustrating a case where the support arm is positioned in the sheet feeding state of the document tray, FIG. 4B is a diagram illustrating a case where the support arm is retracted from the loading surface of the document tray to a retracted position, and FIG.
FIG. 10 is a diagram illustrating a case where the support arm is retracted to a position where the separation unit is replaced.

FIG. 12 is a schematic configuration diagram for holding a support arm according to the present invention at a predetermined position.

FIG. 13 is a diagram illustrating a schematic configuration of an image forming apparatus main body.

[Explanation of symbols]

 Reference Signs List 5 sheet stacking means (document tray) 6 sheet feeding means (pickup roller) 60 rear end passage detecting means (rear end passage detecting sensor) 76 rotating means (paper feed drive motor) 80 rotating means (vertical drive motor) 90 Moving means (supporting arm) 92 Driving means (frame rotating gear) 93 Driving means (moving motor) 94 Driving means (driving gear) 98a Position detecting means (sensor) 98b Position detecting means (sensor) 98c Position detecting means (sensor) 117 Separation unit (feed roller)

Claims (6)

[Claims] 1. A sheet stacking means for stacking sheets, a sheet feeding means for feeding a sheet stacked on the sheet stacking means to a separation section on a downstream side, and feeding the sheet feeding means. A sheet conveying device including a rotating unit configured to rotate between a position and a standby position, wherein the sheet feeding unit and the rotating unit are supported, and the sheet feeding unit and the rotating unit are mounted on the sheet. Selectively move to a retreat position where sheets can be stacked with respect to the stacking means, to a feeding position for conveying the sheets stacked on the sheet stacking means, or to an exchangeable exchange position of the separation unit. And a rotatable moving means for causing the sheet to be conveyed. 2. The moving means supports a rear end passage detecting means for detecting that a rear end of the sheet conveyed from the sheet stacking means to the separating section has passed through the sheet feeding means. The sheet conveying device according to claim 1, wherein: 3. The apparatus according to claim 1, further comprising a driving unit configured to selectively rotate the moving unit to one of the retracted position, the feeding position, and the exchange position. Sheet transport device. 4. A position detecting means for detecting whether the moving means is located at the retracted position, the feeding position or the replacement position; and the moving means is moved to the retracted position by the position detecting means.
4. A control means for stopping the driving means when it is detected that the driving means is located at one of the feeding position and the exchange position.
The sheet conveying device according to claim 1. 5. An image reading apparatus comprising: the sheet conveying device according to claim 1; and a document reading unit that reads a sheet document fed from the sheet conveying device. apparatus. 6. A sheet conveying device according to claim 1, a document reading device for reading a sheet document fed from the sheet conveying device, and image information read by the document reading device. And an image forming means for forming an image on a recording sheet based on the image forming apparatus.