JP3666950B2 - Sheet material transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for automatically feeding a sheet material placed on a sheet material placing table, and in particular, a sheet material overlapped by sandwiching the sheet material between two rotating rollers having different conveying directions and conveying forces. The present invention relates to a sheet material conveying apparatus using a retard separation system that separates and conveys a sheet.
[0002]
[Prior art]
Conventionally, a plurality of documents as sheet materials placed on a document placement table are automatically separated one by one and conveyed to an image reading unit such as a copying machine or an image scanner to read image information of the document. Things have been done.
[0003]
As an image reading method, for example, a document placed on a platen glass is irradiated with light, reflected light or transmitted light of the obtained image information is folded using a plurality of mirrors, and an imaging lens is used. A device that reads image information by forming an image on an image sensor or a photoreceptor is known.
[0004]
FIG. 21, FIG. 22, FIG. 23, FIG. 24 regarding such a conventional document reading device (hereinafter referred to as a main body) and a document conveying device (hereinafter referred to as ADF) that automatically transports a document to this document reading device. Will be described.
[0005]
FIG. 21 is a schematic diagram for explaining a cross section of the main body and the ADF, and FIG. 22 is a diagram for explaining an ADF document transport system. FIG. 23 is a diagram for explaining an ADF drive transmission system, and FIG. 24 is a sequence diagram of document reading when an ADF is used.
[0006]
As shown in FIG. 21, the ADF 116 is placed on the main body 117. The original G ′ is placed on the paper feed tray 107 with the reading surface facing upward and the first page at the top.
[0007]
The lifting plate 108 is moved to the maximum ascending position (state shown by a two-dot chain line in FIG. 21) and the maximum descending position (state shown by a solid line in FIG. 21) by two micro switches (not shown). It is possible to control the document G ′ so that it is in the maximum lowered position when the operator places the document G ′ and moves to the maximum raised position when the document G ′ is fed / conveyed.
[0008]
The original G ′ is fed by the feeding roller 101, but when a plurality of originals G ′ are fed, the original G ′ is separated by the separation unit including the separation upper roller 102 and the separation lower roller 103, Only the top document is transported.
[0009]
Thereafter, the original G ′ is further conveyed in the direction of the reading position A ′ by the first conveying roller 104 and the second conveying roller 105, and after the image information of the original G ′ is read, the original G ′ is conveyed by the paper discharge roller 106 and discharged. The paper is discharged onto the paper tray 109 with the reading surface facing downward.
[0010]
Further, when the ADF 116 is used to convey and read a document, the main body 117 appropriately moves the optical systems U1 and U2 so that the document can be read at the reading position A ′. Then, the light source 10 irradiates the original, forms an image on the image sensor 115 using the folding mirrors 111, 112, 113 and the imaging lens 114, and reads the image.
[0011]
FIG. 22 shows the rotation direction of each roller during document conveyance when the document is conveyed using the ADF 116. In FIG. 22, 118 a, 118 b, and 118 c are idle rollers that are in contact with and contact the first transport roller 104, the second transport roller 105, and the paper discharge roller 106, respectively.
[0012]
FIG. 23 illustrates a drive transmission system of the ADF 116. There are two drive sources, a stepping motor 119 and a DC motor 141. The stepping motor 19 serves as a drive source for each roller, and the DC motor 141. Is a drive source of the lifting plate 108.
[0013]
The DC motor 141 is connected to the worm gear 142 and the cam-equipped worm wheel 143, and the lift plate 108 is swung up and down by the cam mechanism.
[0014]
The drive for conveying the original G ′ is transmitted to the gear train 120 by the gear 120 a fixed to the shaft of the stepping motor 119, and reaches the gear train 125 by the shaft 124. Drive is transmitted to the shafts 126, 129, and 130 by the gear train 125. Further, the drive is transmitted to the gear train 133 by the shaft 130 and reaches the shafts 134 and 139.
[0015]
The first conveying roller 104 and the gear 125 d are fixed to the shaft 124, and the driving force is transmitted to the gear train 125. An idle roller 118a is disposed on the first transport roller 104 so as to be urged by a spring 146a.
[0016]
Here, when the stepping motor 119 rotates in the first direction, the first conveyance roller 104 conveys the document G ′ in the downstream direction, and this rotation direction is assumed to be the first rotation direction (FIG. 22). (CCW rotation direction in which the first conveyance roller 104 is rotating).
The drive reaching the gear train 125 is transmitted to the shaft 126 fixed to the gear 125c, the shaft 129 fixed to the gear 125a, and the shaft 130 fixed to the gear 25f. The shaft 126 transmits driving force to the shaft 128 via the torque limiter 127. The shaft 128 transmits driving to the separation lower roller 103. Further, the lower separation roller is urged against the upper separation roller 102 by a spring 146d. When the first conveying roller 104 rotates in the first direction, the lower separation roller 103 receives a driving force that rotates in the opposite direction to the first conveying roller 104 (this is the second rotating direction). Become.
[0017]
A discharge roller 106 is fixed to the shaft 129, and an idle roller 118c is configured to be urged against and contact the discharge roller 106 by a spring 146c. The paper discharge roller 106 rotates in the opposite second direction when the first transport roller 104 rotates in the first direction.
[0018]
The second conveying roller 105 is fixed to the shaft 130, and the idle roller 118b is biased by a spring 146b. Similarly, when the first transport roller 104 rotates in the first direction, the second transport roller 105 similarly rotates in the first direction.
[0019]
Further, the shaft 130 is connected to the gear 133 a via the electromagnetic clutch 131 and the shaft 132. The gear 133d is engaged with the shaft 134 via the one-way clutch 151. The separation upper roller 102 and the toothed pulley 136 are fixed to the shaft 134, and the one-way clutch 152 engaged with the apparatus main body is provided. is there. The separation upper roller 102 is configured to rotate in the second direction when the first transport roller 104 rotates in the first direction.
[0020]
The one-way clutch 151 engaged with the gear 133d is configured to transmit driving in a state where the gear 133d is rotating in the second direction. Further, the one-way clutch 152 engaged with the apparatus main body prevents the shaft 134 from rotating in the first direction. This is because the shaft 134 is connected to the lower separation roller 103 when the electromagnetic clutch 131 is not driven. This is to avoid being driven around by driving.
[0021]
The drive transmitted to the shaft 134 is transmitted to the shaft 139 via the toothed pulley 136 and the toothed belt 137. The feed roller 101 is fixed to the shaft 139, and when the first transport roller 104 rotates in the first direction, it rotates in the second direction.
[0022]
Here, to summarize the rotation direction in which each roller is driven, when the first conveying roller 104 is rotating in the first direction, the second conveying roller 105 rotates in the same direction, and the feeding roller 101 and the separation roller are separated. The upper roller 102, the separation lower roller 103, and the paper discharge roller 106 rotate in the reverse direction.
[0023]
However, the driving of the lower separation roller 103 is transmitted via the torque limiter 127, and the tangential force generated by the driving force transmitted from the upper separation roller 102 and the lower separation roller 103 is the tangential force of the separation upper roller. Since the tangential force of the lower separation roller is set to be smaller than that of the lower separation roller, the separation lower roller 103 rotates with the upper separation roller 102 and rotates in the first direction when a document is normally fed. To do.
[0024]
A document reading method using the ADF 116 having the above configuration will be described with reference to a document reading sequence diagram of FIG.
[0025]
In FIG. 24, DCM is a DC motor 141, MSW1 is a micro switch that detects the maximum raising position of the lifting plate, SPM is a stepping motor 119, MSW2 is a micro switch that detects the maximum lowering position of the lifting plate, and ECL is the electromagnetic clutch 131. It is shown.
[0026]
First, when the main body power is turned on (S101), the DC motor 141 is driven to move the elevating plate 108 to the maximum lowered position (S102 to S104). When the original is set on the paper feed tray 107, the original detection sensor is turned on and a reading start operation is started, and the optical system U1 of the main body 117 moves to the position A ′ so that the original conveyed by the ADF 116 can be read (S105). To S107).
[0027]
Next, the stepping motor 119 is driven and the electromagnetic clutch 131 is set in the drive transmission (ON) state (S108). Then, the lift plate 108 is moved to the maximum lift position by the DC motor 141, and the maximum lift position is held for a predetermined time by the microswitch that detects this state (S109 to S111).
[0028]
Here, the first transport roller 104 and the second transport roller 105 rotate in the first direction, and the separation upper roller 103 and the paper discharge roller 106 rotate in the second direction. Further, since the electromagnetic clutch 31 is in the ON state, the feeding roller 101 and the separation upper roller 102 also rotate in the second direction. At this time, the lower separation roller 103 is rotated around the upper separation roller 102 by the torque limiter 127.
[0029]
The document is fed by being pressed against the feeding roller 101. When the original is caught in the nip between the separation upper roller 102 and the separation lower roller 103, the DC motor is driven to move the lifting plate 108 to the maximum lowered position, and the maximum lowering is performed by the microswitch that detects that this state is reached. The position state is maintained (S112 to S114).
[0030]
When the document end detection sensor for detecting the state in which the document is caught in the nip between the first conveying roller 104 and the idle roller 118a is turned on (S115), the electromagnetic clutch 131 is set in the non-drive transmission state (S116). The rotation of the feeding roller 101 and the separation upper roller 102 is stopped.
[0031]
Further, the original is conveyed in the reading position A ′ direction by the first conveying roller 104 and the second conveying roller 105 to read the image information (S117). Thereafter, the paper discharge roller 106 discharges the original to the paper discharge tray 109 (S118).
[0032]
If the document still exists in the paper feed tray 107, the process returns to S108 to read the next document (S119), and if there is no document, the reading is finished (S120).
[0033]
Next, a second conventional example will be described with reference to FIGS. 25, 26, and 27. FIG. FIG. 25 is a main cross-sectional view of the second conventional example, FIG. 26 is an arrow view of the transport system of the second conventional example, and FIG. 27 is a diagram for explaining the drive transmission system of the second conventional example.
[0034]
The outline of the apparatus of the second conventional example is almost the same as that of the first conventional example, and the original G ′ is set on the paper feed tray 207 with the first page facing upward. The feed roller 201 is swingable in the direction of the arrow A201 about the rotation shaft 234 of the separation upper roller 202. When the document reading is started by the ADF 216, the feed roller 201 is lowered and the document G Carry '.
[0035]
Then, only the uppermost document is transported by the separation unit composed of the separation upper roller 202 and the separation lower roller 203, transported by the first transport roller 204, the second transport roller 205, and the paper discharge roller 206, and discharged. The paper is discharged to the paper tray 209 (FIGS. 25 and 26).
[0036]
The drive transmission system of the second conventional example will be described with reference to FIG. The driving source is only the stepping motor 219, and the motor is used by rotating it forward and backward. FIG. 27A shows a drive transmission path when the stepping motor 219 is driven in the first direction, and FIG. 27B shows a drive transmission path when the stepping motor 219 is driven in the second direction.
[0037]
The drive transmission path is composed of four paths distributed from the gear 255, and is separated from the feed roller 201 via the gear 256, the toothed belts 237a and 237b, the gear 236a, the shaft 238, the gears 236b and 236c, and the shaft 239. A first path for transmitting drive to the roller 202.
[0038]
A second path for transmitting drive to the pickup arm 262 via the shafts 260 and 261.
[0039]
A third path for driving the gear 259 via the shaft 257 and the gear train 258 (gears 258a, 258b, 258c) and a fourth path for driving the gear 259 via the shafts 260, 263.
[0040]
Here, the gear 259 transmits driving force to the first and second transport rollers 204 and 205 and the paper discharge roller 206. The one-way clutches 251, 252, 253, and 254 are in a non-drive transmission state when shown in a broken state, and are in a drive transmission state when shown as a rectangle.
[0041]
As can be seen from FIG. 27, when the stepping motor 219 is rotated in the first direction, the driving force is transmitted to the gear 259 through the third path, and when the stepping motor 219 is rotated in the second direction. The driving force is transmitted to the gear 259 through the fourth path.
[0042]
Therefore, since the gear 259 rotates in the same direction regardless of the rotation direction of the stepping motor 219, the first and second transport rollers 204, 205 and the paper discharge roller 206 always rotate in the same direction.
[0043]
Further, the feeding roller 201 and the separation upper roller 202 are also configured to transmit only the driving force in the first rotational direction of the stepping motor 219 by the one-way clutch 251.
[0044]
[Problems to be solved by the invention]
However, in the conventional configuration as described above, if the document bundle is fed while the document bundle is caught in the nip of the separation roller pair when the document is set, the separation upper roller and the feed roller are always only in the direction of conveying the document. The rotating document is transported as it is, and the separation ability of the separation roller pair cannot be exhibited.
Therefore, not only the normal paper feeding operation cannot be performed, but also a large amount of originals are caught in the nip and the driving load is increased. If the motor is forcibly driven as it is, the motor and the driving system will step out. , Paper feeding failure may occur.
[0045]
Further, in order to reduce the motor torque, when the document is caught in the conveying roller downstream of the separating unit, the driving of the roller of the separating unit is turned off, so that the separating operation may be interrupted in the first conventional example. If the previous document separation operation is insufficient, double feeding will be caused.
[0046]
The present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to have a bundle of sheet materials caught in the nip of the separation roller pair when the sheet materials are placed on the document table. Even if it is in a normal state, it has a means to return the sheet material in the opposite direction and return it to the normal position to release this state, so that stable document separation / feeding can be performed and the transport system It is an object of the present invention to provide a sheet material conveying device having a simple configuration.
[0047]
[Means for Solving the Problems]
  In order to achieve the above objective,Tomorrow,
  A sheet material mounting table on which a plurality of sheet materials are stacked;
  A feeding means for feeding in contact with the sheet material placed on the sheet material placing table;
  The sheet material is changed by changing the relative position between the sheet material mounting table and the feeding means.Of the feeding meansPosition moving means for contacting or separating from the feeding roller;
  A pair of separation rollers for nipping and conveying the sheet material fed by the feeding means one by oneWhen,
  A one-way clutch for transmitting a driving force for causing the feeding roller of the feeding means to rotate forward in the conveying direction from the pair of separating rollers;
  Reversing prevention means for preventing reversal of the feeding roller of the feeding means,
  The separation roller pairBut,Normal rotationandCan be driven selectively in two reverse directionsConfigured,
  Sheet material and feeding means by the position moving meansWhenIn a state where,The separation roller pairButReverseBe done
  This is a sheet material conveying apparatus.
[0049]
The separation roller pair has a separation upper roller supplied via a driving force connecting means that can selectively supply a driving force from the driving means, and a driving force in a direction opposite to the conveying direction of the separation upper roller. It is also preferable to include a lower separation roller that is supplied via the driving force limiting means.
[0050]
It is also preferable that the position moving means is a sheet material lifting / lowering means disposed on the conveying direction side of the sheet material mounting table, or changing the position of the feeding means.
[0051]
Further, it is preferable that the position moving unit changes a relative position between the sheet material placing table and the feeding unit a predetermined number of times in a state where the pair of separation rollers is reversed.
[0052]
Therefore, with the above configuration, the pair of separation rollers can be rotated forward and backward, and the pair of documents sandwiched between the nips of the separation roller pair can be reversed by rotating the separation roller pair in reverse before the sheet material feeding operation. Therefore, the sheet material can be reliably separated and conveyed.
[0053]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
The present invention will be described below based on the illustrated embodiments. In this embodiment, a description will be given based on a sheet material conveying device (hereinafter referred to as ADF) mounted on the upper portion of the image scanner main body.
[0054]
FIG. 1 shows a form in which the image scanner 70 is used as a part of a computer system. The host computer 71 and the image scanner 70 can communicate with each other via an I / F cable 72. The image scanner 70 is controlled by the host computer 71. The image scanner 70 has an ADF 16 mounted on the upper portion of the main body 17.
[0055]
The ADF 16 has a rotatable hinge foot 73 and is mounted so that the hinge foot 73 engages with a hinge foot hole 74 of the main body 17 so that the hinge foot 73 can be opened and closed. Both image information can be read.
[0056]
2A shows a state where the book B is being read, and FIG. 2B shows a state where the sheet material S is being read.
[0057]
FIG. 3 is a cross-sectional explanatory view showing the internal configuration of the main body 17 and the ADF 16. Below the platen glass 21 of the main body 17, a first mirror unit U 1 including a light source 10 and a first mirror 11, a second mirror unit U 2 including a second mirror 12 and a third mirror 13, an imaging lens 14, and an image. There is an optical system composed of the sensor 15.
[0058]
When an image of a document that cannot use the ADF 16 such as a book is read by the main body, the first mirror unit U1 and the second mirror unit U2 are driven in parallel with the document table glass 21 at a speed ratio of 1: 1/2. By doing so, the original on the platen glass is read.
[0059]
In the case of a sheet document, reading is performed using the ADF 16. For reading by the ADF 16, first, the document S is set on the ADF 16, and then the first mirror unit U1 is moved to a position where the document conveyed by the ADF 16 can be read (position A in the figure). The original is read by transporting the original S without driving the optical system of the main body.
[0060]
Next, the movement of each roller and the drive transmission method will be described with reference to FIGS. The internal configuration of the ADF 16 follows the first conventional example. In this embodiment, however, the stepping motor 19 rotates in both forward and reverse directions, the feeding roller 1 as feeding means, and the separation The configuration of the driving portion of the roller 2 is different, and different components will be mainly described below.
[0061]
As shown in FIG. 4, the driving of the stepping motor 19 can be selectively connected to the gear train 20 (20a to 20c), the shaft 24, the gear train 25 (25a to 25f), the shaft 30, and the driving force of the stepper motor 19. Is transmitted to the shaft 34 through the electromagnetic clutch 31, the shaft 32, and the gear train 33 (33 a to 33 d).
[0062]
A gear 33 d, the separation upper roller 2, and a toothed pulley 36 are fixed to the shaft 34, and the driving force is transmitted to the toothed pulley 47 by a toothed belt 37.
[0063]
Further, the toothed pulley 47 transmits the drive to the shaft 39 via the one-way clutch 51. The shaft 39 has a one-way clutch 52 to which the feed roller 1 is fixed and engaged with the apparatus main body.
[0064]
When the stepping motor 19 rotates in the first direction (arrow A1 direction in FIG. 4), the rotation direction of each roller is the same in the first direction (arrow A2) as the first conveyance roller 4 and the second conveyance roller 5. , A3 direction), the feed roller 1, the separation upper roller 2, the separation lower roller 3 and the paper discharge roller 6 are directions in which the sheet material is conveyed, and a second direction opposite to the first direction. It rotates in the direction of arrows A4, A5, A6 and A7. However, the lower separation roller 3 is limited in driving force supplied by the torque limiter 27 and is rotated around the separation upper roller 2.
[0065]
The one-way clutch 51 is arranged so as to transmit drive to the shaft 39 when the toothed pulley 47 is rotating in the second direction, and the one-way clutch 52 is such that the toothed pulley 47 rotates in the first direction. And the rotation of the shaft 39 in the first direction is locked by the engagement with the main body of the apparatus, thereby preventing the feeding roller 1 from rotating in the first direction.
[0066]
Here, the shaft 39 should not rotate because it is in the non-drive transmission direction of the one-way clutch 51, but actually rotates due to the idling torque of the one-way clutch 51.
[0067]
Accordingly, when the stepping motor 19 rotates in the first direction and the electromagnetic clutch is in the OFF state, the separation upper roller 2 rotates with the separation lower roller 3 and rotates in the first direction. The accompanying drive is transmitted to the toothed pulley 47 by the toothed belt 37.
[0068]
Further, when the feed roller 1 rotates in the first direction (the direction opposite to the arrow A4 direction on which the feed roller 1 in FIG. 5 is described), the original set on the paper feed tray 7 (particularly, there are many originals, In the case of curling, the document may come into contact with the feeding roller 1), which causes a paper feed failure. However, the second way of the shaft 39 is caused by the one-way clutch 52. Rotation in the direction does not occur, and there is no paper feed failure.
[0069]
6 and 7 show a state in which the stepping motor 19 is rotating in the second direction (the direction of the arrow A11), and the first conveying roller 4 and the second conveying roller 5 are rotated in the second direction. The separation upper roller 2, the separation lower roller 3, and the paper discharge roller 6 rotate in the first direction (arrows A15, A16, A17). However, the feeding roller 1 is not rotated by the one-way clutch 52.
[0070]
Here, the rotational direction of each roller is organized using FIG. In FIG. 8A, when the stepping motor 19 is driven in the first direction and the electromagnetic clutch 31 is ON, the first transport roller 4 (the second transport roller is not shown) rotates in the first direction, Then, the feeding roller 1 and the separation upper roller 2 (the paper discharge roller is not shown) rotate in the second direction (sheet material conveyance direction), and the separation lower roller 3 rotates in the first direction.
[0071]
In FIG. 8B, when the stepping motor is driven in the first direction and the electromagnetic clutch 31 is in the OFF state, the first conveying roller 4 (second conveying roller, not shown) rotates in the first direction, and The lower separation roller 3 rotates in the second direction. The feeding roller 1 does not rotate, and the separation upper roller 2 rotates with the separation lower roller 3 in the first direction.
[0072]
In FIG. 8C, when the stepping motor is driven in the second direction and the electromagnetic clutch is ON, the first transport roller 4 (the second transport roller is not shown) rotates in the second direction and is separated. The upper roller 2 rotates in the first direction, the feed roller 1 does not rotate, and the separation lower roller 3 rotates along with the separation upper roller 2 and rotates in the second direction.
[0073]
With reference to FIGS. 9, 10, and 11, a method for swinging the lift plate and a method for controlling the maximum lift position and the maximum drop position of the lift plate will be described. FIG. 9 is a front view of the lifting plate, FIG. 10 is a front view C1 arrow view, FIG. 11 is a front view C2 arrow view.
[0074]
The elevating plate 8 is engaged with the shaft 22, and the shaft 22 is rotatably supported with respect to the apparatus main body. A cam lever 23 is fixed to the shaft 22. Further, the cam lever 23 is biased upward by a spring 46 (see FIG. 11), and the swing position of the cam lever 23 is determined by the rotational position of the cam-equipped wheel 43.
[0075]
The cam-equipped wheel 43 and the gear 42 constitute a worm gear mechanism (see FIG. 10A), and the DC motor 41 is driven by rotating the cam-equipped wheel 43, and the cam shape of the cam-equipped wheel 43 and the cam lever 23 move up and down. The plate 8 swings (FIG. 10B is the maximum ascending position and FIG. 10C is the maximum descending position).
[0076]
Further, the side surface of the cam-equipped wheel 43 opposite to the cam shape is formed by two arcs (FIG. 11B). By combining this shape with the microswitches 44 and 45, the maximum ascending position and the maximum descending position are determined. The microswitch is turned on at the outer arc 43a and turned off at the inner arc 43b. That is, when the DC motor is driven, the state of the microswitch is monitored to determine the maximum ascending and descending positions, the DC motor is stopped at each position, and the position control of the lifting plate is performed.
[0077]
A document presence / absence detection method will be described with reference to FIG. As shown in FIG. 12, a document presence / absence detection lever 48 that is rotatably supported by the apparatus main body is provided above the elevating plate 8. The document presence / absence detection lever 48, the elevating plate 8, and the apparatus main body are arranged so as not to engage with each other (FIGS. 12A and 12B). As shown in FIG. 12B, the document presence / absence detection lever 48 has a shape that blocks the optical axis of the photo interrupter 50 while being supported by the apparatus main body without receiving external force (hereinafter referred to as photo). The state where the optical axis of the interrupter is interrupted is the OFF state, and the state where the optical axis is not interrupted is the ON state).
[0078]
When the document G is set on the paper feed tray 7, the document presence / absence detection lever 48 is swung by receiving an external force from the document, the document presence / absence detection lever 48 opens the optical axis of the photo interrupter 50, and the photo interrupter is turned on. It will be in an ON state (FIG.12 (c)). When the original G disappears from the paper feed tray 7, the original presence / absence detection lever 48 swings again, interrupts the optical axis of the photo interrupter, and is turned off. That is, the presence or absence of the document on the paper feed tray is detected by monitoring the state of the photo interrupter.
[0079]
The document separation method will be described with reference to FIG. The document separation method applied to the present invention is called a retard separation method. The separation upper roller 2 and the separation lower roller 3 are configured to rotate in the same direction. The driving force is transmitted via the figure, and the strength of the tangential force generated by the driving force is set so that the tangential force of the lower separation roller is smaller than the tangential force of the upper separation roller. When the original document is being conveyed or when the original document is not being conveyed, the lower separation roller 3 rotates with the upper separation roller 2 (FIG. 13A).
[0080]
When a plurality of originals are transported, the tangential force between the originals and the frictional force generated between the originals are set to be smaller than the tangential force of the lower separation roller. Force> tangential force of separation lower roller> friction force between documents, separation upper roller 2 conveys the upper document, and separation lower roller 3 rotates in a direction to push the lower document back toward the paper feed tray. (FIG. 13B). In FIG. 13, only two sheets of documents are double-fed. However, no matter how many sheets are fed, the lower separation roller 3 feeds the lower side of the original until the number of originals to be conveyed becomes one. Rotate in the direction pushing back in the direction. Then, when the conveyed document becomes one sheet, the separation lower roller 3 is rotated with the separation upper roller 2 (FIG. 13C).
[0081]
The document edge detection method will be described with reference to FIG. On the conveyance path between the first conveyance roller 4 and the second conveyance roller 5, a document edge detection sensor 49 including a document edge detection lever 49 and a photo interrupter 50 for controlling document reading timing and the like is disposed. The document edge detection lever 49 is rotatably supported by the apparatus main body, and has a shape that blocks the conveyance path and blocks the optical axis of the photo interrupter 50 without receiving external force (FIG. 14). (A), (b)). When the original G is conveyed by the first conveying roller 4, the original end detection lever 49 is swung by the original G, and when the optical axis of the photo interrupter 50 is opened, the photo interrupter 50 is turned on (FIG. 14 ( c)). Thereafter, when the original disappears from the conveyance path, the optical axis of the photo interrupter 50 is again cut off, and the photo interrupter 50 is turned off. That is, the document end can be detected by monitoring the state of the photo interrupter 50.
[0082]
Next, FIG. 15 and FIG. 16 show sequence diagrams in the case of reading. FIG. 17 illustrates the operation of this sequence diagram. In the figure, DCM is a DC motor 41, MSW1 is a micro switch for detecting the maximum raising position of the lifting plate, SPM is a stepping motor 19, MSW2 is a micro switch for detecting the maximum lowering position of the lifting plate, and ECL is an electromagnetic clutch 31. Is shown.
[0083]
Since the power is supplied from the main body, when the main body is turned on (S01), the ADF is in a pre-preparation state, and the elevating plate is at the maximum lowered position so that the user can easily set the original. The DC motor is driven to enter a standby state until the document detection sensor is turned on (S02 to S04).
[0084]
When the user sets a document (S05) and receives a reading start signal from the host computer (S06), the image scanner starts reading.
[0085]
First, preparation before feeding is performed. When the original is set, if the original bundle is thick or the original is curled, the original bundle may bite into the nip between the separation upper roller 2 and the separation lower roller 3 as shown in FIG. . If the sheet feeding operation is performed in this state, the driving load increases, which may cause motor step-out or double feeding.
[0086]
Therefore, by driving the stepping motor 19 in the second direction (S08), the document that has digged into the nip between the separation upper roller 2 and the separation lower roller 3 is discharged, so that normal feeding operation and separation operation can be performed. To do. At this time, if the elevating plate is swung several times at the same time, it is useful for discharging the original and aligning the original (FIG. 17B). Then, the stepping motor 19 is stopped, the lifting plate is set to the maximum lowered position, and the process proceeds to the next step.
[0087]
In FIG. 17B, the feeding roller 1 is stopped, but the separation upper roller 2 is rotated along with the separation lower roller 3, and the document is continuously discharged so that the document is not caught in the nip of the separation roller pair. In this state, the stepping motor is not stepped out due to an increase in the driving load, and the occurrence of double feeding of documents is prevented.
[0088]
FIG. 16 is a continuation of FIG. 15, and next, the stepping motor 19 is driven and the electromagnetic clutch 31 is set in the drive transmission (ON) state (S11). Then, the lift plate 8 is moved to the maximum lift position by the DC motor 41, and the maximum lift position is held for a predetermined time by the microswitch that detects this state (S12 to S14).
[0089]
Here, the first transport roller 4 and the second transport roller 5 rotate in the first direction, and the separation upper roller 3 and the paper discharge roller 6 rotate in the second direction. Further, since the electromagnetic clutch 31 is in the ON state, the feeding roller 1 and the separation upper roller 2 also rotate in the second direction. At this time, the separation lower roller 3 is rotated around the separation upper roller 2 by the torque limiter 27 (see FIG. 17C).
[0090]
The document is started to be fed by being pressed against the feeding roller 1. When the original is caught in the nip between the separation upper roller 2 and the separation lower roller 3, the DC motor is driven to move the lifting plate 8 to the maximum lowered position, and the maximum lowering is performed by the micro switch that detects that this state is reached. The position state is maintained (S15 to S17).
[0091]
When the document end detection sensor for detecting the state in which the document is caught in the nip between the first conveying roller 4 and the idle roller 18a is turned on (S18), the electromagnetic clutch 31 is set in the non-drive transmission state (S19). The rotation of the feeding roller 1 and the separation upper roller 2 is stopped (see FIG. 7).
[0092]
Further, the original is conveyed in the reading position A direction by the first conveying roller 4 and the second conveying roller 5 to read the image information (S20). Thereafter, the paper discharge roller 106 discharges the original to the paper discharge tray 109 (S21).
[0093]
If the document still exists in the paper feed tray 7, the process returns to S11 to read the next document (S22), and if there is no document, the reading ends (S23).
[0094]
(Embodiment 2)
In the second embodiment, the present invention is applied to a sheet material conveying apparatus having the same configuration as that described in the first embodiment. However, the driving capable of selectively supplying the driving force from the driving means. The document G placed on the sheet feed tray 7 serving as the sheet material placing means is reversed using the electromagnetic clutch 31 serving as the force connecting means and the driving force of the separation lower roller 3 in the direction opposite to the document conveying direction. It is conveyed in the direction.
[0095]
FIG. 18 shows a sequence diagram for performing image reading with this configuration. The drive transmission method, the rotation direction of each roller, and the sequence at the time of reading a document (FIG. 16 only) are the same as those in the first embodiment.
[0096]
Since the sequence S1 to the sequence S07 is the same as that in FIG. In sequence S08A, when the stepping motor is driven in the first direction with the electromagnetic clutch 31 in the OFF state before reading the document, the separation upper roller 2 rotates with the separation lower roller 3 and is caught in the nip between the conveyance roller and the separation lower roller. It is rotated in the direction of discharging the original document (the state from FIG. 17A to FIG. 17B).
[0097]
Then, after a predetermined time has elapsed, the driving of the stepping motor is stopped (S10A). Therefore, it is possible to prevent the occurrence of double feeding of documents by the movement of each roller in the sequence S08A.
[0098]
Incidentally, the swinging of the lifting plate of the first and second embodiments has no problem using a solenoid instead of the DC motor 41 employed in the embodiment.
[0099]
(Embodiment 3)
Further, in the first and second embodiments, the form in which the paper feed tray 7 swings and the original is brought into contact with the feed roller is shown, but the same diagram as that described in the second conventional example is shown. The same operation can be performed even when the feeding roller 1 is swung by the pickup arm 62 as shown in FIG. In FIG. 19, the other components are the same as those of the first embodiment described above, and the same components are denoted by the same reference numerals and description thereof is omitted.
[0100]
The drive system of the third embodiment will be described with reference to FIG. A one-way clutch 239a that transmits only the driving force in the direction in which the sheet material is conveyed to the shaft 239 that rotates the feeding roller 201, and a one-way clutch 239b that serves as an anti-reverse means for inhibiting the feeding roller 201 from rotating in reverse. Prepare. The one-way clutches 251 and 254 are electromagnetic clutches.
[0101]
Other configurations are the same as those in FIG. 27, and by rotating the motor 219 in the direction of discharging the document caught in the nip of the separation roller pair and controlling the electromagnetic clutches 251E and 254E, The same effect as in the second embodiment can be obtained.
[0102]
Also in the third embodiment, the pickup arm 62 can be swung using a solenoid or the like.
[0103]
Although the embodiment has described the ADF of the image scanner, the present invention can also be applied to a general image forming apparatus, for example, an apparatus that automatically conveys a document attached to a copying machine, a facsimile, or the like.
[0104]
【The invention's effect】
In the present invention having the configuration and operation described in the above embodiment, since the separation roller pair rotates in the direction opposite to the direction in which the sheet material is conveyed, the separation roller pair is engaged with the separation roller pair when the sheet material is placed. By returning the inserted sheet material in the direction toward the sheet material mounting table, stable document separation and paper feeding can be performed.
[0105]
Further, since the feeding roller is provided with a one-way clutch and a reverse rotation preventing means, the feeding roller that feeds the placed sheet material does not rotate in the reverse direction. Even if the sheet material comes into contact with the sheet material, the sheet material does not return too much and cannot be fed.
[0106]
Further, the driving of the conveying roller, which is one roller of the separation roller pair, is cut off, and the sheet material is moved in the direction of the sheet material mounting table by the driving force in the direction opposite to the sheet material conveying direction of the lower separation roller, which is the other roller. It is possible to return.
[0107]
The position moving means assists the discharge of the sheet material caught in the separation roller pair by changing the relative position between the sheet material mounting table and the feeding roller a predetermined number of times while the separation roller pair is reversed. At the same time, the sheet material can be aligned.
[Brief description of the drawings]
FIG. 1 is a diagram of a sheet material conveying apparatus as an embodiment to which the present invention is applied.
FIG. 2 is a diagram of a usage form of a sheet material conveying apparatus to which the present invention is applied.
FIG. 3 is an explanatory cross-sectional view illustrating an internal configuration of a sheet material conveying apparatus.
FIG. 4 is an explanatory diagram of a drive transmission system (forward rotation).
FIG. 5 is a cross-sectional explanatory view in the vicinity of a pair of separation rollers.
FIG. 6 is an explanatory diagram of a drive transmission system (reverse rotation).
FIG. 7 is a cross-sectional explanatory view in the vicinity of a pair of separation rollers.
FIG. 8 is a diagram for explaining the rotation direction of each roller.
FIG. 9 is a front view of the lifting plate.
FIG. 10 is a C1 arrow view of the lifting plate.
FIG. 11 is a C2 arrow view of the lifting plate.
FIG. 12 is a diagram illustrating document presence / absence detection.
FIG. 13 is a diagram for explaining a document separation method;
FIG. 14 is a diagram for explaining a document edge detection method;
FIG. 15 is a sequence diagram when reading a document (first part);
FIG. 16 is a sequence diagram when reading a document (second part).
FIG. 17 is a diagram for explaining the operation of the separation roller pair in a state where a document is placed.
FIG. 18 is a sequence diagram at the time of reading a document according to the second embodiment (first stage portion).
FIG. 19 is an explanatory sectional view of the vicinity of a separation roller pair according to the third embodiment.
FIG. 20 is an explanatory diagram of a drive transmission system according to a third embodiment.
FIG. 21 is an explanatory cross-sectional view showing a configuration of a first conventional sheet material conveying apparatus.
FIG. 22 is a cross-sectional explanatory view of the vicinity of a separation roller pair of a first conventional example.
FIG. 23 is an explanatory diagram of a drive transmission system of a first conventional example.
FIG. 24 is a sequence diagram when reading a document of a first conventional example.
FIG. 25 is a cross-sectional explanatory view showing a configuration of a sheet material conveying apparatus of a second conventional example.
FIG. 26 is a sketch showing a configuration of a sheet material conveying apparatus of a second conventional example.
FIG. 27 is an explanatory diagram of a drive transmission system of a second conventional example.
[Explanation of symbols]
1 Pickup roller (feeding means)
2 Separation upper roller
3 Separate lower roller
4 First transport roller
5 Second transport roller
6 Paper discharge roller
7 Paper tray
8 Lift plate (position change means)
9 Output tray
10 Light source
11 First mirror
12 Second mirror
13 Third mirror
14 Imaging lens
15 Image sensor
16 ADF (sheet material conveying device)
17 Body
18a, 18b, 18c Idle roller
19 Stepping motor (drive means)
20 Gear train
24 shaft
25 Gear train
26 Shaft
27 Torque limiter (driving force limiting means)
28 Shaft
29 Shaft
30 shaft
31 Electromagnetic clutch (connection means)
32 shaft
33 Gear train
34 Shaft
36, 47 Toothed pulley
37 Toothed belt
39 Shaft
41 DC motor
42 Gear
43 Wheel with cam
44, 45 micro switch
51 One-way clutch (one-way clutch)
52 One-way clutch (reverse rotation prevention means)

Claims (6)

A sheet material mounting table on which a plurality of sheet materials are stacked;
A feeding means for feeding in contact with the sheet material placed on the sheet material placing table;
Position moving means for bringing the sheet material into contact with or separating from the feeding roller of the feeding means by changing the relative position between the sheet material placing table and the feeding means;
A pair of separation rollers that sandwich and convey the sheet material fed by the feeding means one by one ;
A one-way clutch for transmitting a driving force for causing the feeding roller of the feeding means to rotate forward in the conveying direction from the pair of separating rollers;
Reversing prevention means for preventing reversal of the feeding roller of the feeding means,
The separation roller pair is configured to be selectively driven in two directions of normal rotation and reverse rotation ,
Sheet conveying apparatus and the sheet material and the feeding means while being in contact away, characterized in that the separation roller pair is reversed by the position moving means. The separation roller pair includes a separation upper roller that is supplied via a driving force connecting unit that can selectively supply a driving force from the driving unit;
The reverse of the driving force to the conveying direction of the separation on roller, the driving force according to claim 1 Symbol placement of the sheet material conveying apparatus characterized by comprising a separation lower roller supplied through the limiting means. It said position moving means, according to claim 1 or 2 Symbol placement of the sheet material conveying device, characterized in that a sheet lifting means arranged in the conveying direction of the sheet material mounting table. Said position moving means, said separation roller pair claim 3 Symbol placement of the sheet material conveying device, characterized in that a predetermined number of times changing the relative position of the sheet material mounting table and the feeding means in a state in which reverse . Said position moving means, according to claim 1 or 2 SL placing the sheet conveying device and changing the position of said feeding means. It is configured to be able to transport a sheet material from which an image is read by an image sensor,
When a reading start signal is supplied, the separation roller pair is driven in the reverse direction,
After the separation roller pair is driven in the reverse rotation direction, the separation roller pair is driven in the normal rotation direction to separate and convey the sheet material fed by the feeding means.
The sheet material conveying device according to any one of claims 1 to 5, wherein

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