JP2584142B2 - Automatic document feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder, and more particularly, to a method for feeding stacked documents one by one to an image forming apparatus.
The present invention relates to an automatic document feeder for returning each supplied document to the original in the stacked state.

[0002]

2. Description of the Related Art An automatic document feeder disclosed in Japanese Patent Application Laid-Open No. 1-197236 has a document storage section having a rear end regulating plate for aligning the rear end of a document and a document storage section from a document storage section to a platen of a copying machine. A document feed unit that supplies the documents one by one, and a document return unit that returns the documents supplied to the document table of the copier to the document storage unit are provided. The document return section has a mechanism for returning the document so that the rear end of the document is disposed near the rear end regulating plate.

In this automatic document feeder, stacked documents are stored in a document storage unit. The documents stored in the document storage unit are supplied one by one to a document table of a copying machine by a document feeding unit. The document for which the copying operation has been completed is returned from the document table to the document storage unit by the document return unit.

In the operation of the document returning section, the returning operation is performed such that the rear end of the document is close to the rear end regulating plate. When the document makes one round, the trailing edge regulating plate pushes the stacked documents toward the document feeder, and the leading end of the document reaches the document feeder. As a result, the document in the document storage unit can be transported again by the document feeding unit.

[0005]

In the conventional automatic document feeder, the document return section returns the document to the document storage section such that the rear end of the document is close to the rear end regulating plate. And
The trailing edge regulating plate pushes the document in the document storage unit, and causes the leading end of the document to reach the document feed unit. The operation of pushing out the document by the trailing edge regulating plate does not cause any problem when the sizes of the documents are all the same.

However, some originals have the same width but different lengths in the feeding direction. For example, an A4 size document and an A5 size document may be mixed.
At this time, even if the trailing edge of the document is pushed out by the trailing edge regulating plate, the leading edge of the smaller document does not reach the document feeder. Therefore, in the conventional automatic document feeder, when documents of different sizes are mixed, the document re-feeding operation cannot be performed normally.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic document feeder capable of normally re-transporting a document even when documents of different sizes are mixed.

[0008]

SUMMARY OF THE INVENTION An automatic document feeder according to the present invention is an apparatus for feeding stacked documents one by one to an image forming apparatus and returning each fed document to the stacked documents. This device includes a document storage unit, a document feed unit, a document
And a return unit. The document storage section is in the document transport direction.
It has a document holder for holding the leading end on the downstream side.
Documents of different sizes can be stored together. original
The document feeder sends the document from the document storage to the image forming apparatus.
Supply one by one. The document return section is provided to the image forming apparatus side.
Depending on the size of the fed document,
And a discharge roller movably supported downstream.
The leading edge on the downstream side in the document transport direction reaches the document
The document is returned to the document storage unit by moving the discharge roller.

[0009]

In the automatic document feeder according to the present invention, stacked documents are stored in the document storage section. In this storage state,
The leading end of the document is held by the document holding unit. In this state,
Documents are supplied one by one from a document storage unit to the image forming apparatus side by a document feeding unit. The document supplied to the image forming apparatus is returned to the document storage unit by the document return unit such that the leading end of the document reaches the document holding unit.

In this case, the original is returned to the original storing section so that the leading end of the original reaches the original holding section. Therefore, even if originals of different sizes are mixed, the leading end of the original is held in the original holding section. And the document is re-conveyed normally.

[0011]

FIG. 1 shows an automatic document feeder according to an embodiment of the present invention. The automatic document feeder 1 is arranged on the upper end surface of the copying machine 2. Automatic document feeder 1
The document storage unit 3 includes a document storage unit 3 disposed at the upper center, a document feed unit 4 disposed on the left side of the document storage unit 3 in the drawing, and a document return unit 5 disposed on the right side of the drawing. A transport belt 7 is arranged at a position facing the contact glass 6 arranged at the center of the upper end of the copying machine 2.

The document storage unit 3 has a document tray 10 on which documents in a stacked state are placed. At the end of the document tray 10 on the side of the document feeder 4, a document stopper 11 and a document pressing plate 12 whose posture is switched between a solid line position and a two-dot chain line position by a solenoid (not shown) are provided. When the document stopper 11 is disposed above (in a solid line posture), its leading end protrudes above the document tray 10 and can come into contact with the front end of the document. When the document stopper 11 is disposed below (in the position indicated by the two-dot chain line), the entire document stopper 11 is disposed below the document tray 10. On the other hand, the document pressing plate 12 is disposed above the document stopper 11. When the document pressing plate 12 is disposed above (in a solid line posture), the document pressing plate 12 is in a posture in which a document can be inserted, and when it is disposed below (in a position indicated by a two-dot chain line), it is in a document pressing posture.

The document stopper 1 of the document tray 10
A forward feed roller 13 is further disposed at a portion where the document 1 and the document pressing plate 12 are disposed. Forward feed roller 13
Has a partially cutout shape, and is rotated by a drive mechanism (not shown). The front feed roller 13 is configured such that a part thereof can protrude above the document tray 10 when rotated, and can feed a document to the document feed unit 4 by rotating counterclockwise in FIG.

An open / close fulcrum 14 is provided above the document tray 10.
The tray cover 15 is provided so as to be rotatable around the center. The open / close fulcrum 14 is supported by a cover 16 that covers the entire automatic document feeder 1.

The document feeder 4 has a paper feed roller 20 and a separation roller 21 arranged on the document tray 10 side. The original tray 10 is controlled by the rollers 20 and 21.
The originals sent from the side are separated one by one. A transport path 22 composed of a pair of plate members is provided between the rollers 20 and 21 and the transport belt 7. A registration roller pair 23 is provided in the middle of the conveyance path 22 to correct the conveyance posture of the document. At the end of the conveyance path 22 on the side of the conveyance belt 7, there is provided a switching claw 25 that is rotatable around a rotation start point 24 between a position indicated by a solid line and a position indicated by a dashed line.

Further, there is provided a reversing device 26 that branches off from the downstream end and the center of the transport path 22. Reversing device 2
Reference numeral 6 mainly includes a reversing roller 27 and a transport path 28 connecting the reversing roller and the transport path 22.

The transport belt 7 is stretched over a number of rollers 30 arranged at intervals from each other along the upper surface of the contact glass 6. As a result, the lower end surface of the conveyor belt 7 faces the contact glass 6.

The document returning section 5 connects the transport belt 7 and the document storage section 3 and is provided at the right end of the automatic document transport apparatus 1 in FIG. The document return section 5 has a large-diameter drive roller 40 and a discharge belt 41 stretched over the drive roller 40. The discharge belt 41 includes an end roller 42 disposed below the document tray 10, an auxiliary roller 43 disposed adjacent to the drive roller 40, a discharge roller 44 disposed above the document tray 10, And is substantially C-shaped.

As shown in FIG. 2, the shaft 4 of the end roller 42
5 is supported by a slide bearing 46. The slide bearing 46 is movable in a guide groove 47 formed in the cover 16. The guide groove 47 is a groove extending in parallel with the document tray 10 (FIG. 1). The rotation shaft 48 of the discharge roller 44 is supported by a slide bearing 49. The slide bearing 49 can move in a guide groove 50 formed in the cover 16 in parallel with the guide groove 47.

The two bearings 46 are fixed to a belt 51 extending between the guide grooves 47 and 50. The left and right ends of the belt 51 in FIG. 2 are hung on a pair of pulleys 52 and 53. The pulley 52 near the drive roller 40 is fixed to a center shaft 54, and the center shaft 54 is
Output shaft. The pulley 53 has a central shaft 56.
It is supported rotatably. The auxiliary roller 43
Is rotatable about a shaft 54.

The center shaft 57 of the driving roller 40 is connected to the output shaft of the DC motor 58. Further, as shown in FIG. 3, a plurality of sponge rollers 60 are fixed to the shaft 57 so as to sandwich the drive roller 40. The sponge roller 60 is made of, for example, a flexible polyurethane foam such as “Molten Prene Foam” manufactured by Inoac Corporation, and other related rollers 40, 42, 43, and 44.
The rigidity is extremely low compared to. Further, as shown in FIG. 1, a transport path 61 composed of a pair of plate-like members is provided between the roller 40 and the document return unit 5 side portion of the transport belt 7.
Is provided. In the transport path 61, a pair of transport rollers 62 are arranged.

As shown in FIG. 1, the discharge cover 63 covers the drive roller 40 and the sponge roller 60 from outside.
Is provided. The discharge cover 63 is rotatable about an opening / closing fulcrum 64. The opening / closing fulcrum 64 is supported by the cover 16.

A rib 65a is formed on the inner surface of the discharge cover 63. The rib 65 a extends from the end of the transport path 61 on the drive roller 40 side to the document storage unit 3 along the direction in which the discharge belt 41 extends. Also, as shown in FIG.
Each rib 65a has its tip extending a distance b closer to the shaft 57 than the outer peripheral surface of the sponge roller 60. However, the tip of the rib 65a is further away from the shaft 57 by a distance a than the discharge belt 41 that is hung on the outer peripheral surface of the drive roller 40. That is, the tip of the rib 65a is located on the outer peripheral side of the discharge belt 41 with respect to the shaft 57,
0 is located on the inner peripheral side of the outer peripheral surface.

As shown in FIG. 1, the rib extending continuously from the rib 65a to the lower surface of the tray cover 15 (the range between the position of the solid line and the position of the dashed line) of the discharge roller 44. 65b are provided. The rib 65b formed on the lower surface of the tray cover 15
5 and also serves to reinforce the strength of the tray cover 15. As shown in FIG. 4, a part of the rib 65 a linearly extending from the roller 40 to the lower surface of the tray cover 15 and the rib 65 b are separated from the outer peripheral surface of the discharge belt 41 whose leading end is hung over the discharge roller 44. Also protrudes toward the shaft 48 by a distance c.

The control section 7 of the automatic document feeder 1 shown in FIG.
0 includes a microcomputer including a CPU, a ROM, a RAM, and the like. The controller 70 controls the document tray 10
A document detection sensor 71 for detecting whether or not a document is placed in the document tray, a size detection sensor 72 for detecting a document size when the document passes through the conveyance path 22, A round detection sensor 73 for detecting one round of the placed document is connected. The control unit 70 includes a document pressing plate driving unit 74 for driving the document pressing plate 12, a stopper driving unit 75 for driving the document stopper 11, and a stepping motor 55 for driving the discharge roller 44. , A belt circulating unit 77 including a DC motor 58 for circulating the discharge belt 41, and other input / output units. Further, the control unit 70 includes the copying machine 2
The control unit 78 including a microcomputer provided on the main body side is also connected.

Next, the operation of the above embodiment will be described with reference to FIGS.
1 will be described according to the control flowchart shown in FIG. When the program starts, in step S1 in FIG. 7, initial settings such as disposing the document stopper 11 and the document pressing plate 12 at positions indicated by solid lines are performed. After the initialization, the program proceeds to step S2.

In step S2, the control section 7 of the copier body side
8 to wait for a document supply command. If an original supply command is received from the copying machine main body side control unit 78, step S3
Move to In step S3, the document detection sensor 71 determines whether a document is present on the document tray 10. If the document does not exist, the document cannot be supplied to the copying machine 2 side, so the process proceeds to step S4. In step S4, error processing such as outputting an error signal to the copying machine main body side control section 78 is executed. Upon completion of the process in the step S4, the process returns to the step S2.

If it is determined in step S3 that there is a document, the process proceeds to step S5. Step S
In step 5, by checking the operation mode setting state in the copying machine main body side control unit 78, it is determined whether or not the mixed size mode is designated. If the mixed-size mode has not been designated, the flow shifts to step S6 to execute a normal document conveying operation. On the other hand, if the mixed-size loading mode is designated, the process proceeds to step S7, and the transport operation in the mixed-size loading mode is executed.

FIGS. 8 and 9 show the control flow of the normal transport operation in step S6. Step S in FIG.
At 10, the document stopper 11 and the document pressing plate 12 are lowered to the position indicated by the two-dot chain line in FIG. As a result, the restriction on document conveyance by the document stopper 11 is released, and the leading end of the document is held by the document pressing plate 12.

Next, in step S11, a command to start a document supply operation is issued. As a result, a series of document supply operations such as rotation of the paper feed roller 20 counterclockwise is started. In step S12, the length of the original that has passed through the transport path 22 is detected by the size detection sensor 72.
Subsequently, in step S13, the movement of the discharge roller 44 is started. The movement of the discharge roller 44 is performed by the rotation of the stepping motor 55 in FIG. When the stepping motor 55 rotates, the belt 51 circulates, and the slide bearing 49 moves along the guide groove 50 accordingly. At the same time, the slide bearing 46 is also in the guide groove 4.
Move along 7. Note that the moving amount of the discharge roller is determined according to the document length detected in step S12.

In step S14, the process waits until the operation of setting one document on the contact glass 6 is completed.
When a series of sequence operations are performed and it is determined that a certain document is set on the contact glass 6, the process proceeds to step S15. In step S15, a set completion signal indicating that the setting of the original is completed is output to the copier body side control unit 78. Upon receiving the setting completion signal, the copying machine 2 reads the image information of the document placed on the contact glass 6 and executes a general copying operation such as transferring a toner image to a sheet.

In steps S16 and S17,
It waits for a document discharge command or a document reversal command from the copier body side control unit 78. In the case of a double-sided document, a reversal command is issued from the copying machine main body side control unit 78, and the program shifts from step S17 to step S18. In step S18, a document reversing operation using the reversing roller 27 is performed. Upon completion of the process in the step S18, the process returns to the step S14, and waits for completion of the document setting after the reversing operation. Then, the processing from step S14 is repeated.

When a copy discharge command is issued from the copying machine main body control section 78, the program shifts from step S16 to step S19 in FIG. In step S19, it is determined whether the movement of the discharge roller 44 has been completed. If it is determined that the movement of the discharge roller 44 has been completed, the program proceeds to step S20. In step S20, the document pressing plate 12 is raised to the solid line position. Thereby, the original pressing operation by the original pressing plate 12 is released.

In step S21, a document discharging operation is instructed. Thus, the transport belt 7 starts circulating, and the shaft 57 is driven by the DC motor 58.
As a result, the discharge belt 41 circulates, and the sponge roller 60 rotates. The document on the contact glass 6 passes through the transport path 61 with these operations,
The document is introduced into the document return unit 5.

In the document return section 5, a distance b is provided between the rib 65a and the sponge roller 60 as shown in FIG. The document is conveyed toward the document tray 10. Here, since the sponge roller 60 is formed of a material having low rigidity, even if the document is conveyed in a state of being curved along the outer peripheral surface of the sponge roller 60, the document is wrinkled or the strength of the document is reduced. It does not deteriorate.

The document that has passed through the sponge roller 60 is conveyed while being sandwiched between the discharge belt 41 and the ribs 65a and 65b, which are stretched over the discharge roller 44 as shown in FIG. In this portion, since the original is conveyed in a straight line, the original does not deteriorate even if the hardness of the discharge roller 44 is high. The leading end of the document passing between the discharge belt 41 and the ribs 65a and 65b is
Is discharged toward the document feeder 4 until the paper reaches the lower part of the document.

When the processing in step S21 is completed, the flow shifts to step S22. In step S22, the document holding plate 12 is lowered as shown by the two-dot chain line in FIG. Thus, the original placed on the original tray 10 in a stacked state and the original returned by the original returning unit 5 are held by the original pressing plate 12.

In step S23, the cycle detection sensor 73
It is determined whether or not the last original has been returned based on the detection state. If it is not the final manuscript, the process proceeds to step S24,
The operation of supplying the lowermost document among the documents stacked on the document tray 10 to the contact glass 6 side is started. Upon completion of the process in the step S24, the process returns to the step S14 in FIG.

On the other hand, if it is determined in step S23 that the document is the last one, the process proceeds to step S25, in which the document stopper 11 and the document pressing plate 12 are raised to the position indicated by the solid line. As a result, the document held by the document pressing plate 12 is released, so that the operator can open the tray cover 15 and take out the document. Upon completion of the process in the step S25, the program returns to the main routine in FIG.

If it is determined in step S5 in FIG. 7 that the mode is the mixed size loading mode, the mixed loading transport process of step S7 is performed. In FIG. 10 showing the mixed transport process, in step S30, a counter n for counting the number of pages of the document is set to “0”. In step S31, the document stopper 11 and the document pressing plate 12 are lowered. In step S32, the document supply operation is started. The processing here is the same as step S11 in FIG.

In step S33, the counter n is incremented. In step S34, step S12
The document length is detected in the same manner as in.

In step S35, it is determined whether or not the original is the first sheet based on the counter n. 1 manuscript
If it is, the process proceeds to step S36. Step S
36, the discharge roller 44 is connected to the automatic document feeder 1
To the position corresponding to the smallest document that can be handled. The movement operation at this time is basically the same as step S13. In step S37, it is determined based on the detection result in step S34 whether or not the supplied document is of the minimum size. If it is the minimum size, step S3
8 and set the index X to “1”. On the other hand, if it is determined in step S37 that the document is not the minimum document, the process proceeds to step S39. In step S39,
The index X is set to “0”. Note that the index X
Is “1”, it means that the position of the discharge roller 44 is appropriate, and if “0”, the position of the discharge roller 4
4 means that the position is inappropriate.

When the processing in step S38 or S39 is completed, the flow shifts to step S40 in FIG.

On the other hand, at step S35 in FIG.
If it is determined that the document is not the first document, step S41 is performed.
Move to In step S41, the length of the document handled last time is compared with the length of the current document to determine whether the latter is the same as the former or the latter is smaller than the former. If the length of the document handled this time is longer than the length of the document handled last time, the process moves from step S41 to step S39, and the index X is set to “0”.

If the determination in step S41 is Yes, the process moves to step S42. In step S42, it is determined whether or not the length of the document handled last time is equal to the length of the document handled this time. If they are equal, the process moves to step S38, and the index X is set to "1". On the other hand, step S
If the determination at 42 is No, the process moves to step S43, and the discharge roller 44 is moved to a position corresponding to the current document length.
To move. Thus, the stop position of the discharge roller 44 is closer to the document pressing plate 12 than the rear end position of the previously processed document on the document tray 10. Upon completion of the process in the step S43, the process shifts to a step S38 to set the index X to “1”.

In FIG. 11, steps S40 and S44 to S51 are the same as steps S14 to S22 in FIGS. 8 and 9, and a description thereof will be omitted. However, at the time of document ejection in step S50, the ejection roller 44 is arranged at least at a position corresponding to the length of the document handled last time or at a position closer to the document feeder 4 than that. For this reason, even if the next original is returned from the original return unit 5 onto the original group placed on the original tray 10, the front end of the original returned to the rear end of the previously processed original is There is no collision. Therefore, the leading end of the document can surely reach below the document pressing plate 12.

Upon completion of the process in the step S51, the process shifts to a step S52. In step S52, it is determined whether or not the index X is “1”. Index X
Is "1", the discharge roller 44 has already been arranged at an appropriate position, and the program proceeds to step S5.
Move to 3. If the index X is “0”, it means that the discharge roller 44 has moved too much toward the document feed unit 4 and the trailing end of the returned document does not fall off the discharge belt 41 and cannot be completely removed. Move to step S54.
In step S54, the discharge roller 44 is repositioned at a position corresponding to the document length. Upon completion of the process in the step S54, the process shifts to a step S53.

In step S50, in the case of the first document, the discharge roller 44 is arranged at a position equal to the minimum document length. Here, when the leading end of the discharged document reaches a position corresponding to the document stopper, the driving of the discharge belt 41 is stopped. On the other hand, for the second and subsequent documents, when the current document length is not longer than the previous document length, the stop position of the discharge roller 44 is the same as the previous document, and the same document discharge operation as the previous document is performed. Be executed. If the current document is longer than the previous document, the discharge roller 44 retreats to the document return section 5 to a position equal to the length of the current document in step S54. Thus, when the document is discharged in step S50, the front end of the document does not collide with the rear end of the previous document. In addition, since the discharge roller 44 retreats in step S54, even if the document is long, the document is completely discharged onto the document tray 10.

FIG. 6 shows a state in which the document (A) group is placed on the document tray 10 in the mixed size loading mode. FIG.
As apparent from the above, according to this embodiment, even if originals of a plurality of sizes are included, the front ends thereof are aligned. Therefore, a normal re-conveying operation of the document becomes possible.

In step S53, the round detection sensor 73
Then, it is determined whether or not the document is the final one based on the detection result in step (1). If it is not the final document, the process returns to step S32 in FIG. 10, and the subsequent processes are repeated. If the determination in step S53 is Yes, the process proceeds to step S55, where the document stopper 11 and the document pressing plate 12 are raised, and
Return to the main routine.

If a document jam occurs in the document feeder 4 during the document feeding operation described above, the tray cover 15 is opened around the opening / closing fulcrum 14, and the discharge cover 63 is opened around the opening / closing fulcrum 64. . Thereby, the ribs 65a, 65
b moves away from the belt 41 and the rollers 40 and 60,
Documents that have caused a jam can be easily removed.

[0052]

According to the automatic document feeder of the present invention, the document return section returns the document supplied to the image forming apparatus to the document storage section such that the leading end of the document reaches the document holding section. . Therefore, according to the present invention, the re-conveying operation of the original can be normally performed even in the case of the original having different sizes.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an automatic document feeder as one embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a discharge belt driving portion.

FIG. 3 is a partial sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a partial sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a schematic block diagram of a control unit of the embodiment of FIG. 1;

FIG. 6 is a schematic diagram showing an example of a document storage state.

FIG. 7 is a control flowchart of the embodiment of FIG. 1;

FIG. 8 is a control flowchart of the embodiment of FIG. 1;

FIG. 9 is a control flowchart of the embodiment of FIG. 1;

FIG. 10 is a control flowchart of the embodiment of FIG. 1;

FIG. 11 is a control flowchart of the embodiment of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 automatic document feeder 2 copy machine 3 document storage section 4 document feed section 5 document return section 41 discharge belt 44 discharge rollers 65 a, 65 b rib

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-197236 (JP, A) JP-A-4-179680 (JP, A) JP-A-4-3785 (JP, A) JP-A-3-197 147683 (JP, A) JP-A-3-136070 (JP, A) JP-A-1-197236 (JP, A) JP-A-2-132074 (JP, A) JP-A-2-14669 (JP, A) Actual opening Hei 4-53763 (JP, U)

Claims (1)

(57) [Claims] 1. A document in a stacked state to supply one by one to the image forming apparatus, an automatic document feeder to return on a document of the stacked state of each document fed, the tip of the downstream side of the document Department have a manuscript holding portion for holding a storage-friendly mixed documents of different sizes
A document storage section Noh, wherein the document container unit to the image forming apparatus, wherein the document feeding unit for supplying one by one the originals, according to the size of the supplied document to the image forming apparatus
The document is supported so as to be movable upstream and downstream in the document transport direction.
A discharge roller to be carried, and a downstream side in the conveyance direction of the document.
So that the leading edge of the paper reaches the document holder.
A document return unit that returns the document to the document storage unit by moving a document feeder.