JP2022162748A - Image reading device and image forming apparatus - Google Patents

Abstract

To facilitate removal of a sheet when conveyance of the sheet is stopped.SOLUTION: When the length of a sheet fed from a placement part is a first length shorter than a distance along a conveyance path from an opening to an ejection roller pair on the conveyance path with a cover part opened, after a preceding sheet is fed by a feeding unit, control means causes a plurality of conveying members to convey the preceding sheet while causing a subsequent sheet to stand by at a predetermined position, and subsequently, after a leading end of the preceding sheet reaches the ejection roller pair, causes the feeding unit to feed the subsequent sheet. When the length of the sheet fed from the placement part is a second length longer than the distance along the conveyance path from the opening to the ejection roller pair on the conveyance path with the cover part opened, the control means causes the feeding unit to feed the subsequent sheet so that the distance between a rear end of the preceding sheet and a leading end of the subsequent sheet becomes shorter than that when the sheet with the first length is fed from the placement part.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image reading apparatus that reads image information from a sheet and an image forming apparatus that forms an image on the sheet.

2. Description of the Related Art Some image reading apparatuses are equipped with an automatic document feeder (hereinafter referred to as an ADF) that automatically feeds sheets of documents one by one. The ADF feeds the documents placed on the document tray one by one, passes the reading position of the image sensor, and then discharges them to the output tray, thereby continuously reading image information from multiple documents. (also called skimming).

If a jam (so-called paper jam) or double feeding is detected while the document is being transported by the ADF, the transport of the document is stopped in order to prevent the document from being damaged. Further, the ADF is provided with an openable cover for opening the transport path inside the ADF, and the user can remove the document stopped on the transport path by opening the cover.

Some ADFs have a configuration in which a single motor drives a plurality of conveying members. In Patent Document 1, a single motor drives a plurality of rollers, and when double feeding of a succeeding sheet is detected, conveyance of the preceding sheet is continued until the preceding sheet is discharged onto a document stacking table, and then the driving of the motor is stopped. It is stated that

JP 2018-52684 A

In the above document, document transport is continued even after detection of double feeding. However, in order to prevent document damage, it is desirable to stop transporting documents immediately upon detection of a jam or double feed. There is also Here, in the ADF having a configuration in which a single motor drives a plurality of conveying members, when the driving of the motor is stopped while the subsequent document is being conveyed, the preceding document that is being conveyed ahead of the succeeding document is also conveyed at the same time. Stop. However, when the size of the document is relatively small, the preceding document stops at a position that is difficult for the user to access even when the cover is open, and it is difficult for the user to remove the document.

SUMMARY OF THE INVENTION The present invention provides an image reading apparatus and an image forming apparatus having the same, in which a sheet can be easily removed when conveyance of the sheet is stopped.

According to one aspect of the present invention, a sheet feeder has a stacking unit on which a sheet whose image information is to be read is placed, and a separation unit that separates the sheet, and feeds the sheet while separating the sheets one by one from the stacking unit. a feeding unit, a sensor arranged downstream of the separating section in the sheet conveying direction to detect the sheet, and a plurality of conveyers arranged along the sheet conveying path and conveying the sheet fed by the feeding unit. a motor for driving the plurality of conveying members; driving means capable of starting and stopping driving of the feeding unit while the plurality of conveying members are being driven by the motor; An image reading apparatus comprising: a cover part configured to be able to open a part of a path; and a control means for controlling the motor and the driving means, wherein the plurality of conveying members convey sheets from the conveying path. a pair of discharge rollers for discharging the sheet, and the control means determines that the length of the sheet fed from the stacking portion is the length from the opening of the conveying path to the pair of discharge rollers in a state where the cover portion is opened; When the first length is shorter than the distance along the conveying path, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed to the plurality of conveying members while waiting at a predetermined position. After that, after the leading edge of the preceding sheet reaches the pair of discharge rollers, the following sheet is fed to the feeding unit, and the length of the sheet fed from the stacking section reaches the opening of the cover section. When the second length is longer than the distance along the conveying path from the opening of the conveying path to the discharge roller pair in the state, the sheet of the first length is fed from the receiver. The image reading apparatus is characterized in that the following sheet is fed by the feeding unit so that the distance between the trailing edge of the preceding sheet and the leading edge of the following sheet is shorter than the case.

Another aspect of the present invention has a stacking portion on which a sheet whose image information is to be read is placed, and a separating portion that separates the sheet, and feeds the sheet while separating the sheets one by one from the stacking portion. a sheet feeding unit arranged downstream of the separating section in the sheet conveying direction to detect the sheet; and a plurality of sensors arranged along the sheet conveying path for conveying the sheet fed by the sheet feeding unit. a reading means for reading image information from a sheet conveyed on the conveying path; one motor for driving the plurality of conveying members; An image comprising driving means capable of starting and stopping the driving of a feeding unit, a cover part configured to be able to open a part of the conveying path, and control means controlling the motor and the driving means. A reading device comprising: a first housing in which the reading means is arranged; and a second housing in which the plurality of conveying members are arranged and which can be opened and closed with respect to the first housing, a second housing provided with an open portion in which a part of the conveying path is opened so as to form a space between the first housing and the sheet through which the sheet read by the reading means passes; Further, the plurality of conveying members are arranged in the sheet conveying direction downstream of the opening of the conveying path and upstream of the opening of the second housing when the cover is opened. a pair of rollers, and a pair of discharge rollers for discharging the sheet from the conveying path. If the first length is shorter than the distance along the conveying path from the opening of the path to the discharge roller pair, after the preceding sheet is fed by the feeding unit, the succeeding sheet is caused to wait at a predetermined position. while the preceding sheet is conveyed by the plurality of conveying members, and after the trailing edge of the preceding sheet passes through the pair of conveying rollers, the subsequent sheet is fed to the feeding unit, and is fed from the tray. When the length of the sheet is a second length longer than the distance along the conveying path from the opening of the conveying path to the pair of discharge rollers when the cover is open, the first length The feeding unit feeds the succeeding sheet so that the distance between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet is shorter than when the sheet is fed from the tray. It is an image reading device.

Still another aspect of the present invention has a stacking portion on which a sheet whose image information is to be read is placed, and a separating portion that separates the sheet, and the sheet is fed while being separated one by one from the stacking portion. a feeding unit that feeds the sheet, a sensor that is arranged downstream of the separating section in the sheet conveying direction and detects the sheet, and a sensor that is arranged along the sheet conveying path and conveys the sheet fed by the feeding unit. a plurality of conveying members; reading means for reading image information from a sheet conveyed on the conveying path; one motor for driving the plurality of conveying members; a driving means capable of starting and stopping driving of the feeding unit; a cover part configured to be able to open a part of the conveying path; and a control means controlling the motor and the driving means. An image reading apparatus comprising: a first housing in which the reading means is arranged; and a second housing in which the plurality of conveying members are arranged and which can be opened and closed with respect to the first housing. a second housing provided with an open portion in which a part of the conveying path is opened so as to form a space between the first housing and the sheet through which the sheet read by the reading means passes; wherein the plurality of conveying members are arranged in the sheet conveying direction downstream of the opening of the conveying path when the cover is opened and upstream of the opening of the second housing. a pair of conveying rollers and a pair of discharge rollers for discharging the sheet from the conveying path, wherein a distance along the conveying path from an opening of the conveying path to the pair of discharging rollers is defined as a first distance, and the conveying rollers When the distance along the conveying path from the pair to the pair of discharge rollers is defined as a second distance, the control means determines that the length of the sheet fed from the tray is equal to or greater than the second distance. If the first length is less than one distance, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is waiting at a predetermined position. After that, after the leading edge of the preceding sheet reaches the discharge roller pair, the feeding unit feeds the succeeding sheet, and the length of the sheet fed from the tray is less than the second distance. In the case of two lengths, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is kept waiting at the predetermined position. After the end passes through the conveying roller pair, the feeding unit When the length of the sheet fed from the tray is a third length that is equal to or greater than the first distance, the first length or the second length The feeding unit feeds the succeeding sheet so that the distance between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet is shorter than when the sheet is fed from the tray. It is an image reading device that

According to the present invention, it is possible to facilitate the removal of the sheet when the conveyance of the sheet is stopped.

1 is a perspective view of an automatic document reading apparatus according to Embodiment 1; FIG. 1 is a schematic diagram of an automatic document reading apparatus according to Embodiment 1; FIG. 4A and 4B are schematic diagrams of an operation unit according to the first embodiment; FIG. FIG. 2 is a block diagram showing the control configuration of the automatic document reading apparatus according to the first embodiment; FIG. 4 is a schematic diagram showing the length of the transport path of the automatic document reading device according to the first embodiment; 4 is a timing chart showing the document conveying operation when L1≧Lm in the first embodiment; 4 is a timing chart showing the document conveying operation when L1<Lm in the first embodiment; 4A and 4B are flow charts showing a control example of the automatic document reading apparatus according to the first embodiment; 4A and 4B are diagrams for explaining the cover unit of the ADF according to the first embodiment; FIG. FIG. 2 is a diagram showing the driving configuration of the automatic document reading device according to the first embodiment; 4 is a timing chart for explaining the operation when L1≧Lm in the first embodiment; FIG. 5 is a diagram for explaining the position of a document stopped inside the automatic document reading apparatus according to the reference example; 9 is a timing chart showing the document conveying operation when L1<Lm in the second embodiment; FIG. 4 is a diagram showing an open portion of the ADF according to the embodiment; 9 is a flow chart showing an example of control of the automatic document reading device according to the second embodiment; 10 is a flow chart showing an example of control of the automatic document reading apparatus according to the third embodiment;

Exemplary embodiments of the present disclosure are described below with reference to the drawings.

First, an image reading apparatus according to a first embodiment (Example 1) will be described. FIG. 1 is a perspective view showing an automatic document reading device 10 as an image reading device according to this embodiment. FIG. 2 is a schematic diagram showing a cross-sectional configuration of the automatic document reading device 10 taken along a plane perpendicular to the sheet width direction (main scanning direction during image reading). FIG. 3 is a front view of the operation section 90 provided in the automatic document reading apparatus 10. As shown in FIG. FIG. 4 is a block diagram showing a control configuration of the automatic document reading apparatus 10. As shown in FIG.

As shown in FIG. 1, the automatic document reading device 10 has a reader section 40 that reads image information of a document, and an ADF 20 that automatically feeds the document. Further, the automatic document reading apparatus 10 has an operation section 90 shown in FIG. The operation unit 90 includes a display unit 91 such as a liquid crystal panel, and an operation key group 92 (including an image reading execution button 93) as an input unit. Each section of the automatic document reading apparatus 10 and the operation section 90 are electrically connected to a controller 310 (FIG. 4) that controls the entire apparatus.

The automatic document reading device 10 can be used as a part of the image forming apparatus by being mounted on the upper portion of the main body of the image forming apparatus having an electrophotographic or inkjet image forming unit. When used as a part of the image forming apparatus, the controller 310 may be a controller mounted on the main body of the image forming apparatus to control the entire image forming apparatus, and the operation unit 90 may be the image forming apparatus. It may be the entire user interface. In that case, the controller 310 can execute an image forming operation (copying operation) for forming an image on a recording material by the image forming unit based on image information received from the automatic document reading apparatus 10 . Alternatively, the automatic document reading apparatus 10 can be used as an image reading apparatus independent of the image forming apparatus.

Documents can be printed on a wide variety of papers of different sizes and materials, including plain paper, thick paper, plastic film, cloth, surface-treated sheet materials such as coated paper, and special-shaped sheet materials such as envelopes and index paper. sheets can be used. Also, the document may be blank or may have an image formed on one side or both sides.

As shown in FIG. 2, the reader section 40 has a front side reading unit 104 as reading means for reading image information, a platen glass 102 and an original table glass 101 . The front side reading unit 104 is connected to a belt member 109 driven by an optical motor 225 (FIG. 4) so that it can move under the platen glass 102 and the platen glass 101 in the sub-scanning direction (horizontal direction in the figure, sheet width direction). perpendicular to). Both the platen glass 102 and the document table glass 101 are transparent members (transmissive members) that allow the front side reading unit 104 to optically scan the document through the platen glass 102 and the document table glass 101 .

The ADF 20 functions as a sheet conveying device that conveys a sheet as a document via a reading position of the front side reading unit 104 (and a back side reading unit 212 which will be described later). The ADF 20 includes a document tray 121, an ADF main body 110 internally provided with a transport path 140 for documents fed from the document tray 121, and a discharge tray 122 on which documents discharged from the transport path 140 are stacked. have.

The document tray 121 protrudes from the ADF main body 110, and together with a lower transport guide 123 provided on the ADF main body 110, constitutes a document stacking section 120 as a placement section on which documents are placed. As shown in FIG. 1, the document tray 121 is provided with side regulating plates 125A and 125B as a pair of regulating members for regulating the position of the document by coming into contact with both ends of the document in the sheet width direction. The side regulating plates 125A and 125B are movable in the sheet width direction, and when one of them is moved by an interlocking mechanism (for example, a rack and pinion mechanism) arranged inside the document tray 121, the other is also moved. configured to In this embodiment, the side regulating plates 125A and 125B are configured to move while maintaining a symmetrical positional relationship about the reference position in the seat width direction. In other words, in the present embodiment, the document is conveyed by aligning the center of the document in the sheet width direction with the reference position (conveyance center) in the sheet width direction of the ADF 20 regardless of the size of the document.

Note that the ADF 20 of this embodiment also supports small documents (small size documents) such as receipts and business cards smaller than the standard size. The lower limit of the standard size is, for example, B6 size (long side feeding direction) or A5 size (long side feeding direction).

The ADF 20 also has a feeding unit 20</b>F that feeds documents one by one from the document tray 121 and a plurality of transport members ( 114 , 115 , 117 , 119 ) arranged along the transport path 140 . In the following description, the direction along a typical transport path from the document tray 121 to the discharge tray 122 via the transport path 140 is referred to as the “sheet transport direction” of the ADF 20 .

Further, the ADF 20 has a back surface reading unit 212 as reading means for reading image information from a document, and a platen glass 217 . The platen glass 217 is a transparent member (transmissive member) that allows the back surface reading unit 212 to optically scan the document through the platen glass 217 .

As the front side reading unit 104 and the back side reading unit 212, CIS type image sensor units are used. That is, each of the front side reading unit 104 and the back side reading unit 212 has reading sensors 108 and 216 including light receiving elements arranged in the sheet width direction (see also FIG. 4). Each of the front side reading unit 104 and the back side reading unit 212 includes LEDs 105 and 214 as light sources for irradiating light toward the document, and lens arrays 107 and 215 for forming an image of light reflected from the document on the light receiving surface of the light receiving element. and have Note that a CCD type image sensor unit may be used instead of the CIS type.

As shown in FIG. 2, the feeding unit 20F has a pickup roller 111, a feed roller 112, and a separation roller 113. As shown in FIG. The pickup roller 111 is positioned above the document stacking section 120 and held by a swingable arm 111a. The pickup roller 111 can be moved between a feeding position where it contacts the uppermost document of the stack of documents stacked on the document stacking section 120 and a standby position where it is separated upward from the stack of documents by swinging of the arm 111a. . The pickup roller 111 feeds the document from the document stacking section 120 toward the separation nip between the feed roller 112 and the separation roller 113 by rotating at the feeding position. The feed roller 112 is arranged downstream of the pickup roller 111 in the sheet conveying direction. The separation roller 113 is a roller member connected via a torque limiter to a shaft fixed to the frame of the ADF 20, and contacts the feed roller 112 with a predetermined pressure suitable for document separation.

Note that the feeding unit 20F including the pickup roller 111, the feed roller 112, and the separating roller 113 is an example of the feeding unit, and other configurations may be used. For example, the pickup roller 111 may be omitted, and a support plate that can move up and down may be provided in the document stacking section 120 so that the feed roller 112 starts feeding the document by raising the support plate. The separation roller 113 is an example of a separation member that separates the document by using a frictional force, and receives a driving force (retard driving) in a direction opposite to the sheet conveying direction (clockwise direction in the drawing) via a torque limiter. rollers may be used. A pad-like elastic member that contacts the feed roller 112 may be used as the separating member.

A plurality of conveying members provided along the conveying path 140 are a registration roller pair 114, a read roller pair 115, an intermediate conveying roller pair 117, and a discharge roller pair 119 from upstream to downstream in the sheet conveying direction. including. Among them, the read roller pair 115 is a roller pair positioned upstream in the sheet conveying direction with respect to the reading positions of the front side reading unit 104 and the back side reading unit 212 . The intermediate conveying roller pair 117 is a roller pair positioned downstream in the sheet conveying direction with respect to the reading positions of the front side reading unit 104 and the back side reading unit 212 . In other words, the image information reading position in the present embodiment is provided on the transport path from the read roller pair 115 to the intermediate transport roller pair 117 .

In addition, the ADF 20 has a first document sensor 204, a second document sensor 205, a post-separation sensor 207, and a read sensor 210 as detection means for detecting the presence or absence of documents and the state of transport. (see also Figure 4). Furthermore, the ADF 20 has a transport motor 224, a feed clutch 223, and the like. These configurations will be described later.

By the way, the ADF 20 is rotatably supported by the reader section 40 via a hinge, and has a closed position supported on the upper surface of the reader section 40 (FIG. 1) and an open position moved above the reader section 40 (FIG. 14). can be opened and closed between That is, the reader unit 40 is a first housing of the image reading apparatus, and the ADF 20 is a second housing that can be opened and closed with respect to the first housing.

As shown in FIG. 2, the ADF 20 is provided with a transport guide plate 211A as a facing member that faces the front side reading unit 104 with the platen glass 102 interposed therebetween when the ADF 20 is in the closed position. The transport guide plate 211A guides the document passing through the platen glass 102 so that it does not float above the platen glass 102 . Further, the reader section 40 is provided with a guide surface 211B as a facing member that faces the back surface reading unit 212 across the platen glass 217 when the ADF 20 is positioned at the closed position. Therefore, when the ADF 20 is positioned at the closed position, the document at the reading positions of the front side reading unit 104 and the back side reading unit 212 is positioned between the platen glass 102 and the transport guide plate 211A and between the platen glass 217 and the guide surface 211B. A transport path is formed.

When the ADF 20 is moved to the open position as shown in FIG. 14, the transport guide plate 211A and the platen glass 217 of the ADF 20 are separated upward from the platen glass 102 and the guide surface 211B of the reader section 40 . Therefore, when the ADF 20 is opened, the conveying guide plate 211A and the platen glass 217 of the ADF 20 are exposed when viewed from the front side of the apparatus (front left side in FIG. The document transport path is opened. In other words, when the ADF 20 is open, at least part of the transport path between the read roller pair 115 and the intermediate transport roller pair 117 is open.

(ADF cover unit)
As shown in FIG. 9, the ADF main body 110 is composed of a main body unit 110B and a cover unit 110A. The main unit 110B is a portion supported by the reader section 40 so as to be openable and closable. The cover unit 110A is a cover part that can open a part of the transport path 140 . The cover unit 110A is rotatably supported in the direction indicated by the arrow A1 with the support shaft 110a as a fulcrum with respect to the main body unit 110B. The direction of the rotation axis of the cover unit 110A is the seat width direction, and the cover unit 110A is opened by rotating upward away from the main body unit 110B, and then rotated downward toward the main body unit 110B. is closed by

A portion of the transport path 140 (FIG. 2) of the ADF 20 is configured by a transport guide 140a provided on the cover unit 110A and a transport guide 140b provided on the main unit 110B. Therefore, when the cover unit 110A is opened, the transport guide 140a of the cover unit 110A is separated from the transport guide 140b of the main unit 110B (the transport path 140 is opened). In this state, the user can remove the document stopped in the transport path 140 due to a jam or the like from the transport path 140 . Even if the leading edge of the document is stopped at a position downstream of the transport path 140 between the transport guides 140 a and 140 b in the sheet transport direction, the trailing edge of the document must be exposed through the cover opening 170 . However, it is possible to remove the original. In this case, the user can pull out the document through the cover opening 170 by gripping the trailing edge of the document. Here, the leading end of the document is the downstream end in the sheet conveying direction, and the trailing end of the document is the upstream end in the sheet conveying direction. Further, the position downstream in the sheet conveying direction from the conveying path 140 between the conveying guides 140a and 140b means, for example, a position on the conveying path closest to the support shaft 110a of the cover unit 110A. position.

(ADF driving configuration)
A driving configuration of the ADF 20 will be described with reference to FIG. The ADF 20 has a transport motor 224 as a drive source, and a feed clutch 223 that engages (connects) and disconnects (disconnects) drive transmission from the transport motor 224 to the feed unit 20F.

The transport motor 224 is connected to drive rollers 114a, 115b, 117b, and 119b of a plurality of transport members (114, 115, 117, and 119) of the ADF 20 via a transmission mechanism (eg, gear train) not shown. The drive rollers 114a, 115b, 117b, 119b are driven by the transport motor 224 and rotate together with the driven rollers 114b, 115a, 117a, 119a that follow.

Also, the transport motor 224 is connected to the feeding unit 20F via the feeding clutch 223 . As the feed clutch 223, a known clutch such as an electromagnetic clutch or a dog clutch operated by a solenoid can be used. When the feeding clutch 223 is in the engaged state, the driving force of the conveying motor 224 is transmitted to the feeding unit 20F, and the pickup roller 111, the feed roller 112 and the separation roller 113 are rotationally driven. The feeding clutch 223 is an example of driving means capable of starting and stopping the driving of the feeding unit 20F while the feeding motor 224 is driving the plurality of feeding members (114, 115, 117, 119). Further, the driving force of the transport motor 224 is used to move the arm 111a up and down, so that the pickup roller 111 contacts and separates from the document.

(lock mechanism and sensor)
By the way, as shown in FIGS. 1, 2 and 9, the arm 111a holding the pickup roller 111 has a regulation plate 130 (shutter plate) as a regulation member for regulating the position of the leading edge of the document stacked on the document stacking section 120. ) is provided. When the pickup roller 111 is at the standby position, the regulating plate 130 is locked at a position (regulating position) that abuts against the leading edge of the document to regulate conveyance. In addition, the locking of the regulation plate 130 is released in association with the descent of the pickup roller 111, allowing the document to be conveyed toward the separation nip when the pickup roller 111 is positioned at the feeding position.

As shown in FIGS. 1 and 2, the detection member 160 of the first document presence/absence sensor 204 and the detection member 150 of the second document presence/absence sensor 205 are located upstream of the regulating position of the regulating plate 130 in the sheet conveying direction. They are arranged side by side in the seat width direction. These detection members 160 and 150 are arranged downstream in the sheet conveying direction from the position where the pickup roller 111 contacts the document. As shown in FIGS. 2, 4 and 5, the first document existence sensor 204 is, for example, a photoelectric sensor (photointerrupter) that is shielded by the detection member 160. The detection member 160 is pressed downward by the document and rotated. When it is moved, it outputs an ON signal. The second document presence/absence sensor 205 is, for example, a photoelectric sensor (photointerrupter) that is shielded by the detection member 150, and outputs an ON signal when the detection member 150 is pressed upward by the document and rotated.

As shown in FIG. 2, among the sensors arranged along the conveying path 140 inside the ADF 20, the post-separation sensor 207 is located downstream of the feed roller 112 (separation nip) in the sheet conveying direction and placed higher up. The read sensor 210 is arranged downstream from the registration roller pair 114 and upstream from the read roller pair 115 in the sheet conveying direction. As the post-separation sensor 207 and the read sensor 210, a photoelectric sensor (photointerrupter) can be used to detect that a detection member (flag) protruding in the transport path 140 contacts the document and rotates. Further, as the post-separation sensor 207 and the read sensor 210, a photoelectric sensor that emits light toward the transport path 140 and detects reflected light from the document may be used.

(Original reading operation)
Next, a document reading operation by the automatic document reading device 10 will be described with reference to FIG. The automatic document reading device 10 has a feed reading mode in which the documents stacked on the document tray 121 are conveyed one by one by the ADF 20 while scanning the documents, and a fixed reading mode in which the documents placed on the platen glass 101 are scanned. , to read the image information from the document. The skimming mode is selected when the first document presence/absence sensor 204 detects a document stacked on the document tray 121, or when the user explicitly instructs using the operation unit 90 or the like.

When the reading operation in the flow reading mode is started, the pickup roller 111 descends and comes into contact with the uppermost document on the document tray 121 . Then, the document is conveyed by a pickup roller 111 and conveyed while being separated one by one at a separation nip as a separation portion formed by a feed roller 112 and a separation roller 113 . The separation roller 113 rotates with the feed roller 112 when one document enters the separation nip, and does not rotate when two or more documents enter the separation nip. Therefore, one document in contact with the feed roller 112 is fed from the separation nip, and the other documents do not pass through the separation nip. In this way, the feeding unit 20F feeds the originals while separating them one by one.

In parallel with the descent of the pickup roller 111, the front side reading unit 104 is positioned at a position (position shown in FIG. 2) facing the transport guide plate 211A. Also, the leading edge and the trailing edge of the document that have passed through the separation nip are detected by the post-separation sensor 207, and serve as a reference for the lift timing of the pickup roller 111 and the drive start and drive stop timings. By using the post-separation sensor 207 , for example, the transport of the document can be temporarily stopped when the leading edge of the document reaches the stop position P immediately after passing through the detection position of the post-separation sensor 207 . The document that has passed through the separation nip is conveyed toward the reading position of the front side reading unit 104 by the registration roller pair 114 and the read roller pair 115 .

In the case of front side reading, in which image information is read from one side of the document (the upper side of the document stacked on the document tray 121; is read by Specifically, light is emitted from the LED 105, which is the light source of the front side reading unit 104, to the surface of the document. converted. At this time, line images in the main scanning direction are acquired line by line, and image information as two-dimensional image data is obtained by connecting the acquired line images in the sub-scanning direction. The acquired image information is subjected to image correction in the image processing section 306 (FIG. 4) of the reader section 40 and transferred to the image memory 305 . After passing through the reading position of front side reading unit 104 , the document is conveyed via intermediate conveying roller pair 117 , discharged from conveying path 140 by discharge roller pair 119 , and discharged to discharge tray 122 .

In the case of double-sided reading in which image information is read from both sides of a document, while the document is conveyed from the read roller pair 115 toward the intermediate conveying roller pair 117, the front and back sides of the document (the second side opposite to the first side) are scanned. Image information is read simultaneously. Image reading of the front side by the front side reading unit 104 is the same as in the case of single-sided reading. The back side reading unit 212 irradiates light from an LED 214 as a light source to the back grain of the document, causes the light receiving element of the reading sensor 216 to receive the reflected light from the document through the lens array 215, and performs photoelectric conversion by the light receiving element. Image information as two-dimensional image data is obtained by connecting the line images acquired by the reading sensor 216 in the sub-scanning direction. The image information of the front and back sides acquired by the front side reading unit 104 and the back side reading unit 212 is corrected in the image processing section 306 (FIG. 4) of the reader section 40 and transferred to the image memory 305 .

On the other hand, the fixed reading mode is selected when a sensor arranged near the platen glass 101 detects the document placed on the platen glass 101, or when the user explicitly instructs it by the operation unit 90. be done. In this case, the front side reading unit 104 is moved along the platen glass 101 by the optical motor 225 so that the front side reading unit 104 scans the document without moving the document on the platen glass 101 . The image information acquired by the front side reading unit 104 is transferred to the image memory 305 via the image processing section 306 (FIG. 4) of the reader section 40 .

(Description of block diagram)
FIG. 4 is a block diagram showing a control configuration of the automatic document reading apparatus 10. As shown in FIG. The upper part of FIG. 4 shows the configuration related to the ADF 20 (left side) and the configuration related to the reader unit 40 (right side), and the lower part of FIG. Represents configuration.

First, as shown in the upper part of FIG. A CPU 301 is a central processing unit that controls each unit of the reader unit 40 and the ADF 20 in an integrated manner. A ROM 302 is a storage device that stores a program indicating the content of control to be executed by the CPU 301 and data necessary for executing the program. A RAM 303 is a storage device used as a work area necessary for the CPU 301 to perform control.

The CPU 301 is connected to a transport motor 224 that drives the transport rollers described above in order to realize a document transport function. The conveying motor 224 is connected to the pick-up roller 111 and the feed roller 112 via the feeding clutch 223 so as to be able to be engaged and disconnected. The CPU 301 uses the driving amount of the transport motor 224 to manage the transport distance and current position of the document being transported. The conveying motor 224 of this embodiment is a pulse motor (stepping motor), and the CPU 301 controls the driving amount (rotation amount) of the conveying motor 224 by controlling the number of drive pulses input to the conveying motor 224 . The CPU 301 calculates the transport distance of the document being transported from the number of drive pulses input to the transport motor 224, grasps the current position of the document based on the calculated transport distance, and determines the operation of the transport motor 224 and the feed clutch 223. Determines control timing. The CPU 301 is further connected to the first document presence/absence sensor 204, the second document presence/absence sensor 205, the post-separation sensor 207, and the read sensor 210, and receives input signals from each sensor.

The CPU 301 includes a front side reading unit 104, a back side reading unit 212, an optical motor 225, an optical system HP (home position) sensor 226, an image memory 305, an image processing section 306, and an image transfer section 304 in order to realize the image reading function. It is connected. The front side reading unit 104, the back side reading unit 212, and the optical motor 225 are as described above. The image memory 305 is a storage device that temporarily stores image data read by the front side reading unit 104 and the back side reading unit 212 .

An image processing unit 306 performs image processing for correcting the image data stored in the image memory 305 . For example, the image processing unit 306 performs shading correction on image data based on shading correction data stored in the shading memory 307 . The shading correction data is obtained based on the results of reading the shading thin plates 103A and 103B (FIG. 2) by the front side reading unit 104 and the back side reading unit 212 in advance. The image transfer unit 304 transfers the image data subjected to image processing by the image processing unit 306 to the image transfer unit 314 of the controller 310 via the image transfer line 402 .

A controller 310 controls the entire image reading system including the reader section 40 and the ADF 20 . That is, the control circuit 80 including the controller 310 and the CPU 301 functions as control means for controlling the operation of the image reading apparatus according to this embodiment. As described above, the controller 310 may be a control circuit that controls the entire image forming apparatus including the automatic document reading device 10 . The controller 310 includes a CPU 311 , a ROM 312 , a RAM 313 , an image transfer section 314 and an image memory 315 . A CPU 311 is a central processing unit that controls each unit of the controller 310 in an integrated manner. The ROM 312 is a storage device that stores a program describing the control contents to be executed by the CPU 311 . A RAM 313 is a storage device used as a work area necessary for the CPU 311 to perform control.

The image transfer unit 314 receives image information from the image transfer unit 304 of the reader unit 40 and stores it in the image memory 315 . The operation unit 90 is used to issue operation instructions from the user to the entire image reading system, display messages to the user, and display read images. implement.

The CPU 311 exchanges control commands and control data relating to image reading via the communication line 401 with the CPU 301 . For example, when the user presses the image reading execution button 93 ( FIG. 3 ) of the operation unit 90 , the CPU 311 receives an image reading job start instruction from the operation unit 90 and transmits an image reading start request to the CPU 301 . When the user operates the operation key group 92 of the operation unit 90 to change the setting of image reading, the CPU 311 transmits control information requesting the setting change to the CPU 301 . The setting of image reading includes an instruction of a color mode (black-and-white reading or color reading) of image reading, an instruction of reading resolution, information of document size, and the like. Based on the control information and the image reading start request from the CPU 311, the CPU 301 executes a series of operations (FIG. 8A) as an image reading job.

The CPU 311 also receives a signal representing the state of the automatic document reading apparatus 10 from the CPU 301 and causes the operation unit 90 to display a message to the user according to the state of the apparatus (for example, occurrence of a jam). Specifically, when the CPU 301 detects the occurrence of a jam in the ADF 20, the operation unit 90 informs the user of the occurrence of the jam and the method of removing the document on the display unit 91 (FIG. 3) based on the instruction from the CPU 311. Screen display can be performed. The screen display informing the method of removing the document is, for example, an image and a message specifically instructing any one of the following three methods (A) to (C) or a combination thereof.
(A) Open the cover unit 110A and pull out the document from the cover opening 170;
(B) The ADF 20 is rotated upward to remove the document from the open portion 180 (Fig. 14) of the ADF 20;
(C) Inserting the hand into the discharge tray 122 and pulling out the document from the discharge roller pair 119 .

(Control of document feeding intervals)
Next, control of the interval (document interval) at which the ADF 20 conveys the documents in the flow reading operation (document transport operation) when a plurality of documents are placed on the document tray 121 will be described. The document spacing refers to the distance measured along the transport path 140 from the trailing edge of the preceding document transported earlier in the transport path 140 of the ADF 20 to the leading edge of the succeeding document transported subsequently.

First, the distance between positions on the transport path 140 related to the control of the document spacing will be described. As shown in FIG. 5, the distance from the detection position of the post-separation sensor 207 to the discharge roller pair 119 is Lp. Let Lm be the distance (first distance) from the cover opening 170 of the ADF 20 to the discharge roller pair 119 . Distances Lp and Lm are distances measured along the transport path 140 . The position of the discharge roller pair 119 is based on the position of the nip portion, that is, the position where a straight line connecting the axes of the rollers and the conveying path passing through the nip portion intersect when viewed in the sheet width direction.

The position of the cover opening 170 is based on, for example, the boundary position between the transport guide 140a arranged in the cover unit 110A and the transport guide 141a arranged in the main unit 110B and adjacent to the downstream side of the transport guide 140a ( See Figure 10). The position of the cover opening 170 corresponds to the limit position where the user can access the document when the cover unit 110A is opened (FIG. 9). In other words, when the rear end of the document stopped inside the ADF 20 is positioned upstream in the sheet conveying direction from the position of the cover opening 170, the user can grip the document with the cover unit 110A open. . Conversely, if the trailing edge of the document stopped inside the ADF 20 is located downstream of the position of the cover opening 170 in the sheet conveying direction, it may be difficult for the user to grip the document even if the cover unit 110A is opened. The position of the cover opening 170 is defined as the position where the

In this embodiment, when the document length L1 is equal to or longer than the distance Lm from the cover opening 170 to the discharge roller pair 119, the documents are separated by the first gap L2 between the preceding document and the following document. transport. Further, when the length of the document is shorter than the distance Lm, by temporarily stopping the transport of the succeeding document at a predetermined position, the first space L2 and the second space L3 are provided between the preceding document and the succeeding document. feed the document leaving the Note that the document length L1 is the length in the sheet conveying direction. The first interval L2 and the second interval L3 are determined as follows.

(When L1≧Lm)
First, referring to FIG. 6, a timing chart of the document conveying operation when the document length L1 is equal to or greater than the distance Lm from the cover opening 170 to the discharge roller pair 119, and a first interval which is the document interval in that case. L2 will be explained. FIG. 6 shows ON/OFF of driving of the transport motor 224, ON (engagement)/OFF (disconnection) of the feeding clutch 223, and ON of the post-separation sensor 207 (state in which the document is detected) in the document transport operation. /OFF (a state in which the document is not detected). In the lower part of FIG. 6, the feeding period of the preceding document S1 and the succeeding document S2, which are two documents that are continuously fed (after the leading edge of the document starts to move from the temporary stop position P in FIG. 10) is shown. ) until the trailing end of the .

When the CPU 301 (FIG. 4) receives a document feed start instruction from the controller 310, the CPU 301 starts driving the feed motor 224 and engages the feed clutch 223. FIG. As a result, the pickup roller 111 descends and comes into contact with the preceding document S1 positioned at the top of the document stack on the document tray 121 to feed out the preceding document S1. (time Ta).

When the leading edge of the preceding document S1 that has passed through the separation nip reaches the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from OFF to ON (time Tb). After that, after the leading edge of the preceding document S1 reaches the registration roller pair 114, the feeding clutch 223 is disconnected (time Tc). The CPU 301 determines whether or not the leading edge of the preceding document S1 has reached the registration roller pair 114 based on the number of driving pulses of the transport motor 224 after the post-separation sensor 207 detects the leading edge of the preceding document S1. can be done. After time Tc, the preceding document S1 is transported by transport rollers (registration roller pair 114, read roller pair 115, intermediate transport roller pair 117, discharge roller pair 119) driven by the transport motor 224, and is discharged to the discharge tray 122. be done. On the other hand, since the feed clutch 223 is disengaged at time Tc, even if the preceding document S1 passes through the separation nip, the subsequent document S2 does not pass through the separation nip.

After that, when the trailing edge of the preceding document S1 passes the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from ON to OFF (time Td). Based on the fact that the detection signal of the post-separation sensor 207 is switched from ON to OFF, the CPU 301 engages the feed clutch 223 to separate the succeeding document S2. Here, the CPU 301 can obtain the length L1 of the preceding document S1 based on the number of driving pulses of the transport motor 224 from when the post-separation sensor 207 detects the leading edge of the preceding document S1 until it detects the trailing edge. can. Specifically, the product of the number of drive pulses of the transport motor 224 and the amount of rotation of the transport roller per drive amount for one pulse of the transport motor 224 (for example, the amount of movement of the peripheral surface of the registration roller pair 114) is , the length L1 of the preceding document S1.

When the feeding clutch 223 is engaged at time Td, the pickup roller 111 and the feed roller 112 start feeding the succeeding document S2. After that, when the leading edge of the succeeding document S2 reaches the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from OFF to ON (time Te). Here, the driving pulses of the transport motor 224 are counted from when the trailing edge of the preceding document S1 is detected by the post-separation sensor 207 until when the leading edge of the following document S2 is detected by the post-separation sensor 207 (Td to Te). A first interval L2 is defined as the interval obtained by the above. Note that the horizontal axis of FIG. 6 represents time. They are shown as L1 and L2 (the same applies to FIGS. 7 and 13).

If L1.gtoreq.Lm, the subsequent document S2 is continued to be conveyed with the document spacing of the first spacing L2. Specifically, after the feeding clutch 223 is engaged at time Te as shown in FIG. 6, the succeeding document S2 is conveyed while maintaining the first spacing L2 with respect to the preceding document S1. After the leading edge of the succeeding document S2 reaches the registration roller pair 114, the feeding clutch 223 is disconnected.

The first interval L2 is a document interval that occurs when the timing to start feeding the subsequent document S2 is determined using the post-separation sensor 207 so that the leading edge of the subsequent document S2 does not collide with the trailing edge of the preceding document S1. be. The first distance L2 has a value close to the distance from the separation nip to the post-separation sensor 207 . In other words, the first spacing L2 can be said to be the minimum document spacing that can achieve high throughput (productivity) while avoiding collisions between documents. Therefore, when L1≧Lm, as shown in FIG. 11, the ADF 20 repeats engagement and disengagement of the feed clutch 223 while the transport motor 224 continues to be driven. A high throughput (productivity of scanning operation) can be achieved. Note that if L1≧Lm, even if the transport of the preceding document S1 is stopped at any time, at least the leading edge of the preceding document S1 has reached the discharge roller pair 119, or the trailing edge of the preceding document S1 has reached the discharge roller pair 119. has not passed through the cover opening 170 . Therefore, in this case, there is no need to perform processing for delaying the transport of the succeeding document S2, which will be described below.

(When L1<Lm)
Next, the timing chart of the document conveying operation when the length L1 of the preceding document S1 is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119, and the first interval L2 and the second interval L2 which are the document intervals in that case. The interval L3 will be explained using FIG.

In FIG. 7, the operation up to time Td is the same as in the case of L1≧Lm shown in FIG. However, in FIG. 6, the subsequent document S2 continues to be conveyed even after the post-separation sensor 207 detects the leading edge of the subsequent document S2. When the leading edge of the document S2 is detected, the feeding clutch 223 is disconnected (time Te in FIG. 7). Disengagement of the feeding clutch 223 stops the driving of the feeding unit 20F, and the succeeding document S2 waits at a temporary stop position P (FIG. 2) as a predetermined position. Since the transport motor 224 continues to be driven even while the succeeding document S2 is waiting, the interval between the preceding document S1 and the succeeding document S2 increases.

After that, when the leading edge of the preceding document S1 reaches the discharge roller pair 119, the feeding clutch 223 is engaged again, and transport of the succeeding document S2 is resumed (time Tf). Here, the second gap L3, which is the gap between the preceding document S1 and the succeeding document S2 that is widened by waiting the succeeding document S2, is obtained by using the distance Lp, the length L1 of the document, and the first gap L2. calculated by the formula.
L3=Lp-(L1+L2)

At time Tf, the feeding clutch 223 is engaged again, and the feeding unit 20F is driven by the driving force supplied from the conveying motor 224 via the feeding clutch 223, and the succeeding document S2 is moved from the temporary stop position P. start moving. Then, the succeeding document S2 is conveyed following the preceding document S1 with a gap obtained by summing the first gap L2 and the second gap L3 from the trailing edge of the preceding document S1 to the leading edge of the succeeding document S2. In other words, the second interval L3 is a delay distance for delaying the transport of the succeeding document S2 when the first interval L2 is used as a reference for the document interval. Note that the feed clutch 223 is disconnected after the leading edge of the succeeding document S2 reaches the registration roller pair 114 after the conveyance of the succeeding document S2 is resumed.

With such control, as will be described later, even if the transport of the document is stopped due to the occurrence of a jam or the like at any point after the time Tf at which the transport of the succeeding document S2 is resumed, the user can easily retrieve the preceding document S1. can be removed. As can be seen from the above equation, in this embodiment, the distance (L1+L2+L3) from the leading edge of the preceding document to the leading edge of the succeeding document is constant at Lp during the period after the transport of the succeeding document is resumed. In other words, in this embodiment, when the length of the document is shorter than a predetermined length (Lm), the distance from the leading edge of the preceding document S1 to the leading edge of the subsequent document S2 is constant at Lp regardless of the length of the document. The document spacing between the preceding document S1 and the succeeding document S2 is determined so that .

Even when three or more documents are conveyed, the second document (S2) is treated as a new preceding document, and the third document (S3) is treated as a new succeeding document. is used to apply the document spacing described above. In this case, after the succeeding document (S3), which is the third document, is temporarily stopped at the temporary stop position P, the distance from the trailing edge of the preceding document (S2) to the leading edge of the succeeding document (S3) is the first interval L2. The document is conveyed following the preceding document (S2) while leaving a gap that is the sum of the second gap L3.

(Control example)
The control of the document interval when this embodiment is applied will be described with reference to the flow chart of FIG. 8(a). Each step in the flowchart of FIG. 8A represents processing executed by the CPU 301 executing a program stored in the ROM 302 when the ADF 20 is used to read one side of the document.

The CPU 301 waits while monitoring whether or not the user has set the document on the document stacking unit 120 (S101). When the document is set, that is, the ON signal of the first document sensor 204 is detected (S101: Yes), the CPU 301 waits for reception of a job start (document feeding start instruction) from the controller 310 (S102). When receiving a job start instruction from the controller 310 (S102: Yes), the CPU 301 starts conveying the first document (S103, time Ta in FIGS. 6 and 7). That is, the CPU 301 drives the transport motor 224 and engages the feed clutch 223 to feed the top document on the document stacking section 120 by the pickup roller 111 and the feed roller 112 of the feed unit 20F. let me send

Thereafter, the CPU 301 waits until the post-separation sensor 207 detects the leading edge of the first document, that is, until the post-separation sensor 207 detects an ON signal (S104). After detecting the ON signal of the post-separation sensor 207 (S104: Yes, time Tb in FIGS. 6 and 7), the CPU 301 starts feeding at the timing after the leading edge of the first document reaches the registration roller pair 114. The feed clutch 223 is disconnected (time Tc in FIGS. 6 and 7). Thereafter, the CPU 301 waits until the post-separation sensor 207 detects the trailing edge of the first document, that is, until the post-separation sensor 207 detects an OFF signal (S105). When the OFF signal of the post-separation sensor 207 is detected (S105: Yes, time Td in FIGS. 6 and 7), the CPU 301 obtains the document length L1 (S106). As described above, it is obtained by counting the number of driving pulses of the conveying motor 224 from the detection of the ON signal of the post-separation sensor 207 to the detection of the OFF signal of the post-separation sensor 207 . devil

When the OFF signal of the post-separation sensor 207 is detected (S105: Yes, time Td in FIGS. 6 and 7), the CPU 301 engages the feed clutch 223 to start separating the succeeding document at the separation nip ( S107). Thereafter, the CPU 301 waits until the post-separation sensor 207 detects the leading edge of the succeeding document, that is, until the post-separation sensor 207 detects an ON signal (S108). When the ON signal of the post-separation sensor 207 is detected (S108: Yes, time Te in FIGS. 6 and 7), the CPU 301 obtains the first interval L2. As described above, the first interval L2 is from the detection of the trailing edge of the preceding document by the post-separation sensor 207 (S105: Yes or S112: Yes) to the detection of the leading edge of the subsequent document by the post-separation sensor 207 (S108: Yes). It is obtained based on the number of driving pulses of the transport motor 224 .

The CPU 301 determines whether the length L1 of the acquired document is shorter than the aforementioned distance Lm (the distance from the cover opening 170 to the discharge roller pair 119) (S110). If L1 is equal to or greater than Lm (S110: No), the transport of the succeeding document is continued (S111, after time Te in FIG. 6).

At S110, if L1 is shorter than Lm (S110: Yes), the CPU 301 disconnects the feeding clutch 223 to stop the transport of the succeeding document (S120, time Te in FIG. 7). As a result, the succeeding document is temporarily put on standby at the stop position P. Then, the CPU 301 calculates the second interval L3 (S121). The formula for calculating the second interval L3 is as described above. Then, the CPU 301 waits until the preceding document is conveyed by the second interval L3 (S122). When it is determined that the preceding document has been conveyed by the second interval L3 based on the number of driving pulses of the conveying motor 224 (S122: Yes), the CPU 301 engages the feeding clutch 223 again to resume conveying the succeeding document ( S123, time Tf in FIG. 7). As a result, the succeeding document is conveyed in a state in which the total of the first gap L2 and the second gap L3 is provided from the trailing edge of the preceding document to the leading edge of the succeeding document.

After S211 or S223, the CPU 301 waits until the post-separation sensor 207 detects the trailing edge of the succeeding document, that is, until the post-separation sensor 207 detects an OFF signal (S112). When the OFF signal of the post-separation sensor 207 is detected (S112: Yes), the CPU 301 determines whether or not the document is the final document (S113). The final document is determined when the first document sensor 204 on the document tray 121 is OFF when the OFF signal of the post-separation sensor 207 is detected. If the document being transported is not the final document in S113 (S113: No), return to S106, treat the succeeding document as a new preceding document, treat the next document as a new succeeding document, and execute the processes of S106 to S123. .

The above processing is repeated until it is determined in S113 that the document is the final document being conveyed, and if it is determined that the document is the final document (S113: Yes), this control ends.

As described above, in this embodiment, in the ADF configured to drive a plurality of conveying members with one motor, when the length of the document is shorter than the predetermined distance Lm in the ADF, the leading edge of the preceding document reaches the discharge roller pair. Control is performed to temporarily stop the transport of the succeeding document until it reaches 119 . In other words, the control means sets the length of the sheet fed from the stacker to the first length shorter than the distance along the conveying path from the opening of the conveying path to the discharge roller pair when the cover is open. In this case, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is kept waiting at a predetermined position. After arriving, the feeding unit feeds the succeeding sheet. Here, the first length is the length L1 that satisfies L1<Lm.

As a result, even if the transport motor 224 is stopped due to a transport failure such as jamming or double feeding of the subsequent document after transport of the subsequent document is restarted, at least the leading edge of the preceding document reaches the discharge roller pair 119 . there is For this reason, as shown in FIG. 12 as a reference example, when the driving of the transport motor 224 is stopped after the transport of the succeeding document is started, the document S may not protrude from the cover opening 170 or the discharge roller pair 119 . unlikely to occur. Accordingly, the user can remove the preceding document by gripping the leading edge of the preceding document and pulling it out from the discharge roller pair 119 . Further, the user can remove the succeeding document by opening the cover unit 110A to open the transport path 140 (FIG. 9). Therefore, by applying this embodiment, it is possible to facilitate the removal of the sheet when the conveyance of the sheet is stopped.

In particular, the ADF 20 of this embodiment can convey small size documents such as receipts and business cards smaller than the standard size. According to this embodiment, even if a jam occurs during transport of such a small size document, the possibility of the preceding document stopping at a position inaccessible from the outside of the ADF 20 is reduced, and the document can be easily removed by the user. can be

Also, in this embodiment, when a relatively long document is to be transported, control for delaying the transport of subsequent documents (S120 to S123) is not performed. In other words, the control means sets the length of the sheet fed from the stacker to a second length longer than the distance along the conveying path from the opening of the conveying path to the discharge roller pair when the cover is open. The following sheet is fed to the feeding unit so that the distance between the trailing edge of the preceding sheet and the leading edge of the following sheet is shorter than when sheets of the first length are fed from the receiver. to be fed. Here, the second length is the length L1 that satisfies Lm<L1. As a result, the throughput of the ADF 20 can be improved as compared with the case where the transportation of the succeeding document is always delayed. Particularly, in this embodiment, when the succeeding sheet is not made to wait at the temporary stop position P, the following sheet is fed to the feeding unit 20F based on the post-separation sensor 207 detecting the passage of the trailing edge of the preceding sheet. , high productivity can be achieved.

(jam detection)
FIG. 8B shows an example of control for stopping the driving of the transport motor 224 when a transport failure such as a document jam (paper jam) or double transport is detected in the ADF 20 . During execution of the image reading job (FIG. 8A), the CPU 301 monitors the occurrence of a jam based on detection signals from sensors arranged on the transport path of the ADF 20 (S131). For example, the CPU 301 detects the occurrence of a jam when the post-separation sensor 207 does not detect the leading edge of the document even after a predetermined time has elapsed since the feeding unit 20F was started to be driven. In addition, the CPU 301 prevents the post-separation sensor 207 from detecting the trailing edge of the document even after a predetermined time has passed while the transport motor 224 continues to be driven. jam occurrence is detected. In these examples, the "predetermined time" means the theoretical time at which the leading edge or the trailing edge of the document can be detected if the document is being transported normally based on the setting value of the sheet transport speed. This is the time including a margin to account for misalignment, fluctuations in the transport speed, and the like.

If no jam has been detected (S131: No), the CPU 301 continues executing the job. When the occurrence of a jam is detected (S131: Yes), the CPU 301 stops driving the transport motor 224 (S132). At this time, the CPU 301 immediately stops driving the transport motor 224 without continuing the transport of the preceding document even when the occurrence of the jam of the subsequent document is detected. As a result, for example, even if the subsequent document is a bundle of stapled sheets and a jam occurs, the subsequent document can be prevented from being damaged.

In addition, the CPU 301 notifies the user of the occurrence of a jam by means of screen display, voice alert, etc. by the operation unit 90 (S133). Here, in the present embodiment, the leading edge of the preceding document has reached the discharge roller pair 119 at the time when the transport of the succeeding document, which has been temporarily stopped at the stop position P, is restarted. Therefore, when the occurrence of a jam is detected before the discharge of the preceding document is completed after the transport of the succeeding document is resumed, the operation unit 90 receives information indicating that "insert your hand into the discharge tray 122 and pull out the document from the discharge roller pair 119". is preferably displayed.

Note that although the jam detection method has been described here using the post-separation sensor 207 as an example, the method of detecting a jam, multiple feeds, and other transport abnormalities is not limited to this. The CPU 301 monitors the occurrence of a jam using the lead sensor 210 in the same manner as the method using the post-separation sensor 207 . Further, a sensor for detecting double feeding of documents may be added to the transport path 140 of the ADF 20 . Furthermore, when a sensor for detecting the height of the document surface is provided above the document stacking unit 120 and downstream of the pickup roller 111, the error occurs when a document in which a plurality of sheets are bound is fed. A sensor may be provided to detect the occurrence of a jam by detecting wrinkles in the document.

A second embodiment (second embodiment) of the present disclosure will be described below. In the following description, elements denoted by the same reference numerals as in Embodiment 1 have substantially the same configuration and action as those in Embodiment 1, and portions different from Embodiment 1 will be described. This embodiment differs from the first embodiment in the distance for delaying the conveyance of the subsequent document when the length L1 of the document is equal to or greater than the distance Lm from the cover opening 170 to the discharge roller pair 119. FIG.

In this embodiment, when the document length L1 is equal to or longer than the distance Lm from the cover opening 170 to the discharge roller pair 119, the documents are separated by the first gap L2 between the preceding document and the following document. transport. The first spacing L2 is the same as in the first embodiment. On the other hand, when the length L1 of the document is shorter than the distance Lm, the conveying of the succeeding document is temporarily stopped at a predetermined position, so that the first space L2 and the third space L4 are provided between the preceding and succeeding documents. Feed the document with a gap between them. The third interval L4 is determined as follows.

As shown in FIG. 5, let Lt be the distance measured along the conveying path 140 from the post-separation sensor 207 to the read roller pair 115 .

FIG. 13 shows a timing chart of the document conveying operation when the length L1 of the preceding document S1 is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119 in this embodiment. The operation when the length L1 of the preceding document S1 is equal to or longer than the distance Lm is the same as that of the first embodiment (FIG. 6).

When the CPU 301 (FIG. 4) receives a document feed start instruction from the controller 310, the CPU 301 starts driving the feed motor 224 and engages the feed clutch 223. FIG. As a result, the pickup roller 111 descends and comes into contact with the preceding document S1 positioned at the top of the document stack on the document tray 121 to feed out the preceding document S1. (time Ta).

When the leading edge of the preceding document S1 that has passed through the separation nip reaches the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from OFF to ON (time Tb). After that, after the leading edge of the preceding document S1 reaches the registration roller pair 114, the feeding clutch 223 is disconnected (time Tc). After time Tc, the preceding document S1 is transported by transport rollers (registration roller pair 114, read roller pair 115, intermediate transport roller pair 117, discharge roller pair 119) driven by the transport motor 224, and is discharged to the discharge tray 122. be done. On the other hand, since the feed clutch 223 is disengaged at time Tc, even if the preceding document S1 passes through the separation nip, the subsequent document S2 does not pass through the separation nip.

After that, when the trailing edge of the preceding document S1 passes the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from ON to OFF (time Td). Based on the fact that the detection signal of the post-separation sensor 207 is switched from ON to OFF, the CPU 301 engages the feed clutch 223 to separate the succeeding document S2.

When the feeding clutch 223 is engaged at time Td, the pickup roller 111 and the feed roller 112 start feeding the succeeding document S2. After that, when the leading edge of the succeeding document S2 reaches the detection position of the post-separation sensor 207, the detection signal of the post-separation sensor 207 is switched from OFF to ON (time Te). Here, the driving pulses of the transport motor 224 are counted from when the trailing edge of the preceding document S1 is detected by the post-separation sensor 207 until when the leading edge of the following document S2 is detected by the post-separation sensor 207 (Td to Te). Let the first interval L2 be the interval obtained by

When the post-separation sensor 207 detects the leading edge of the succeeding document S2, the feeding clutch 223 is disconnected (time Te). By disconnecting the feeding clutch 223, the driving of the feeding unit 20F is stopped, and the succeeding document S2 waits at the temporary stop position P as a predetermined position. Since the transport motor 224 continues to be driven even while the succeeding document S2 is waiting, the interval between the preceding document S1 and the succeeding document S2 increases.

After that, when the trailing edge of the preceding document S1 passes through the read roller pair 115, the feeding clutch 223 is engaged again, and the subsequent document S2 is resumed to be transported (time Tf). Here, the third space L4, which is the space between the preceding document S1 and the succeeding document S2, which is widened by waiting the succeeding document S2, is obtained as follows using the distance Lt, the length L1 of the document, and the first space L2. calculated by the formula.
L4 = Lt - L2

At time Tf, the feeding clutch 223 is engaged again, and the feeding unit 20F is driven by the driving force supplied from the conveying motor 224 via the feeding clutch 223, and the succeeding document S2 is moved from the temporary stop position P. start moving. Then, the succeeding document S2 is conveyed following the preceding document S1 with a gap obtained by summing the first gap L2 and the third gap L4 from the trailing edge of the preceding document S1 to the leading edge of the succeeding document S2. In other words, the third interval L4 is a delay distance for delaying the transport of the succeeding document S2 when the first interval L2 is used as a reference for the document interval.

Even when three or more documents are conveyed, the second document (S2) is treated as a new preceding document, and the third document (S3) is treated as a new succeeding document. is used to apply the document spacing described above. In this case, after the succeeding document (S3), which is the third document, is temporarily stopped at the temporary stop position P, the distance from the trailing edge of the preceding document (S2) to the leading edge of the succeeding document (S3) is the first interval L2. The document is conveyed following the preceding document (S2) while leaving a gap that is the sum of the third gap L4.

With such control, as will be described below, even if the transport of the document is stopped due to a jam or the like at any point after the time Tf at which the transport of the succeeding document S2 is resumed, the user can transfer the preceding document S1. can be easily removed. As can be seen from the above formula, in this embodiment, the distance (L1+L2+L3) from the leading edge of the preceding document to the leading edge of the succeeding document is (L1+Lt) in the period after the transport of the succeeding document is restarted, and the length of the document is It changes according to L1. Also, in this embodiment, the shorter the document length L1, the shorter the distance from the leading edge of the preceding document to the leading edge of the succeeding document, and the throughput of the ADF 20 increases.

When the ADF 20 is moved to the open position as shown in FIG. 14, the open portion 180 (the portion including the transport guide plate 211A and the platen glass 217) of the ADF 20 is exposed. The open portion 180 is provided in the ADF 20, which is the second housing, and extends along the conveying path so as to form a space through which the sheet read by the front side reading unit 104 passes between the open portion 180 and the reader portion 40, which is the first housing. A portion of 140 is an open portion. By delaying the transport of the succeeding document S2 as described above, even when the transport motor 224 is stopped after the transport of the succeeding document S2 is resumed, the preceding document S1 stops at least at a position where it passes through the read roller pair 115 . Therefore, the user either opens the ADF 20 and pulls out the preceding document S1 from the open portion 180, or if the preceding document S1 has already reached the discharge roller pair 119, the user grasps the leading edge of the preceding document S1 and discharges it. By pulling it out from the roller pair 119, the preceding document S1 can be removed.

(Control example)
The control of the document interval when this embodiment is applied will be described with reference to the flow chart of FIG. Each step in the flowchart of FIG. 15 represents processing executed by the CPU 301 executing the program stored in the ROM 302 when the ADF 20 is used to read one side of the document. Since the processing of S201 to S213 of this control is substantially the same as S101 to S113 of the control of the first embodiment shown in FIG. 8A, the description thereof will be omitted.

In S210, it is determined whether or not the document length L1 obtained in S206 is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119. FIG. If L1<Lm (S210: Yes), the CPU 301 disconnects the feeding clutch 223 and stops the transport of the succeeding document (S220, time Te in FIG. 13). As a result, the succeeding document is temporarily put on standby at the stop position P. Then, the CPU 301 calculates the third interval L4 (S221). The formula for calculating the third interval L3 is as described above. Then, the CPU 301 waits until the preceding document is conveyed by the third interval L4 (S222). When it is determined that the preceding document has been conveyed by the third interval L4 based on the number of driving pulses of the conveying motor 224 (S222: Yes), the CPU 301 engages the feeding clutch 223 again to resume conveying the succeeding document ( S223, time Tf in FIG. 13). As a result, the succeeding document is conveyed in a state in which a total of the first gap L2 and the third gap L4 is provided from the trailing edge of the preceding document to the leading edge of the succeeding document.

As described above, in the present embodiment, in the ADF configured to drive a plurality of conveying members with one motor, when the length of the document is shorter than the predetermined distance Lm in the ADF, the trailing edge of the preceding document reaches the lead roller. Control is performed to temporarily stop the transport of the succeeding document until it passes through the pair 115 . In other words, the control means sets the length of the sheet fed from the stacker to the first length shorter than the distance along the conveying path from the opening of the conveying path to the discharge roller pair when the cover is opened. In this case, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is kept waiting at a predetermined position. after passing through the feeding unit to feed the succeeding sheet. Further, the control means sets the length of the sheet fed from the stacker to a second length longer than the distance along the conveying path from the opening of the conveying path to the discharge roller pair when the cover is open. , the following sheet is fed to the feeding unit so that the distance between the trailing edge of the preceding sheet and the leading edge of the following sheet is shorter than when the sheet of the first length is fed from the tray. send it. Here, the first length is the length L1 that satisfies L1<Lm, and the second length is the length L1 that satisfies Lm<L1.

As a result, even if the driving of the transport motor 224 is stopped due to a transport failure such as jamming or double feeding of the succeeding document after restarting transport of the succeeding document, at least the trailing edge of the preceding document does not pass through the read roller pair 115 . ing. Therefore, as shown in FIG. 12, when the driving of the transport motor 224 is stopped after the subsequent document is transported, the trailing edge of the document is nipped by the read roller pair 115, and the open portion 180 of the ADF 20 ( 14), the situation in which the preceding document cannot be pulled out is unlikely to occur. Therefore, the user can pull out the preceding document from the open portion 180 of the ADF 20 and remove it. Further, the user can remove the succeeding document by opening the cover unit 110A to open the transport path 140 (FIG. 9). Therefore, by applying this embodiment, it is possible to facilitate the removal of the sheet when the conveyance of the sheet is stopped. Further, according to this embodiment, even if a jam occurs during transport of a small size document, the possibility of the preceding document stopping at a position inaccessible from the outside of the ADF 20 is reduced, and the document can be easily removed by the user. can be In addition, since the sheets of the second length are conveyed at shorter intervals, the throughput of the ADF 20 can be improved compared to the case where the conveyance of subsequent documents is always delayed.

In this embodiment, the shorter the document length L1, the shorter the distance from the leading edge of the preceding document to the leading edge of the succeeding document, and the throughput of the ADF 20 increases. There is an advantage that the throughput can be improved compared to the first embodiment.

When detecting a transport abnormality such as a jam, the CPU 301 notifies the user of the occurrence of a jam by the same method as in the first embodiment, such as screen display and voice alert by the operation unit 90 (see FIG. 8B). S133). Here, in this embodiment, when the transport of the succeeding document stopped at the stop position P is restarted, the trailing edge of the preceding document has passed the read roller pair 115 and then moves toward the discharge roller pair 119 . be transported. Therefore, when the occurrence of a jam is detected before the leading edge of the preceding document reaches the discharge roller pair 119 after the transport of the succeeding document is resumed, "Rotate the ADF 20 upward and open the opening portion 180 of the ADF 20 (FIG. 14) It is preferable to display information to the effect that "remove document from". When the occurrence of a jam is detected after the leading edge of the preceding document has reached the discharge roller pair 119, the operation unit 90 displays information to the effect that ``insert your hand into the discharge tray 122 and pull out the document from the discharge roller pair 119''. and is suitable.

A third embodiment (Example 3) of the present disclosure will be described below. In the following description, elements denoted by common reference numerals in Embodiments 1 and 2 have substantially the same configuration and action as those in Embodiments 1 and 2, and portions different from Embodiments 1 and 2 will be described. The present embodiment differs from the first embodiment in that the control of the document spacing described in the first embodiment and the control of the document spacing described in the second embodiment are switched according to the length of the document.

In the control of the first embodiment, when the length L1 of the document is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119, the distance from the leading edge of the preceding document to the leading edge of the following document in the period after the transport of the succeeding document is restarted (L1+L2+L3) becomes constant at Lp as described above. On the other hand, under the control of the second embodiment, when the document length L1 is shorter than the distance Lm, the distance (L1+L2+L3) from the leading edge of the preceding document to the leading edge of the succeeding document is (L1+Lt) in the period after the transport of the succeeding document is resumed. , and changes according to the length L1 of the document.

Here, as shown in FIG. 5, the distance measured along the conveying path 140 from the read roller pair 115 to the discharge roller pair 119 is Ls. When the length L1 of the preceding document is shorter than the distance Ls, the trailing edge of the preceding document passes through the read roller pair 115 before the leading edge of the preceding document reaches the discharge roller pair 119 . That is, when L1<Ls, the relationship is L1+Lt<Lp, and when Ls≦L1, the relationship is L1+Lt≧Lp. Therefore, when a document shorter than the distance Ls is conveyed, the throughput of the ADF 20 is improved by using the control of the second embodiment rather than the control of the first embodiment. On the contrary, when Ls≦L1, the throughput of the ADF 20 is improved by using the control of the first embodiment rather than the control of the second embodiment.

Therefore, in this embodiment, when the document length L1 is shorter than the distance Lm (first distance), the document length The control is switched according to the depth L1. In other words, when L1<Ls, the transport of the succeeding document is delayed so that the following document is transported with a gap obtained by adding the first gap L2 and the third gap L4 from the preceding document. When Ls≦L1<Lm, the transport of the succeeding document is delayed so that the succeeding document is transported with a space obtained by summing the first space L2 and the second space L3 from the preceding document.

The control of the document interval when this embodiment is applied will be described with reference to the flow chart of FIG. Each step in the flowchart of FIG. 16 represents processing executed by the CPU 301 executing the program stored in the ROM 302 when the ADF 20 is used to read one side of the document. Since the processing of S301 to S313 of this control is substantially the same as S101 to S113 of the control of the first embodiment shown in FIG. 8A, the description thereof will be omitted.

In S310, if the document length L1 obtained in S306 is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119 (S310: Yes), the CPU 301 disconnects the feeding clutch 223 to transport the succeeding document. is stopped (S320). As a result, the succeeding document is temporarily put on standby at the stop position P. Then, the CPU 301 determines whether the document length L1 is shorter than the distance Ls from the read roller pair 115 to the discharge roller pair 119 (S321).

If L1≧Ls (S321: No), the CPU 301 sets the second interval L3 as the distance for delaying the succeeding document (S322). If L1<Ls (S321: Yes), the CPU 301 sets the third interval L4 as the distance for delaying the succeeding document (S323). The method of calculating the second interval L3 and the third interval L4 is as described in the first and second embodiments. Then, the CPU 301 waits until the preceding document is conveyed by the second interval L3 or the third interval L4 set as the delay distance (S324). When it is determined that the preceding document has been transported by the delay distance based on the number of drive pulses of the transport motor 224 (S324: Yes), the CPU 301 engages the feed clutch 223 again to resume transport of the subsequent document (S325). . As a result, the succeeding document is conveyed in a state in which a space obtained by summing the first space L2 and the delay distance is provided from the trailing end of the preceding document to the leading end of the succeeding document.

As described above, in the ADF in which a plurality of transport members are driven by one motor in this embodiment, when the document length is shorter than the predetermined distance Lm in the ADF, transport of the succeeding document is temporarily stopped. control. The period for delaying the transport of the succeeding document is either until the leading edge of the preceding document reaches the discharge roller pair 119 or until the trailing edge of the preceding document passes through the read roller pair 115. Switch according to length. In other words, when the length of the sheet fed from the sheet tray is the first length that is greater than or equal to the second distance and less than the first distance, the control means determines that the preceding sheet has been fed by the feeding unit. Later, the preceding sheet is conveyed by a plurality of conveying members while the succeeding sheet is waiting at a prescribed position, and after that, the succeeding sheet is fed to a feeding unit after the leading edge of the preceding sheet reaches a discharge roller pair. When the length of the sheet fed from the receiver is a second length that is less than the second distance, the control means feeds the succeeding sheet at the predetermined position after the preceding sheet is fed by the feeding unit. The preceding sheet is conveyed by a plurality of conveying members while waiting, and then the succeeding sheet is fed to the feeding unit after the trailing edge of the preceding sheet passes through the pair of conveying rollers. Further, when the length of the sheet fed from the placing section is a third length that is longer than or equal to the first distance, the control means controls that the sheet of the first length or the second length is fed from the placing section. The succeeding sheet is fed to the feeding unit so that the distance between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet is shorter than when the sheet is fed. Here, the first length is the length L1 that satisfies Ls≦L1<Lm, the second length is the length L1 that satisfies L1<Ls, and the third length is the length L1 that satisfies Lm<L1. shall be

As a result, even if the transport motor 224 is stopped due to a transport failure such as jamming or double feeding of the succeeding document after restarting the transport of the succeeding document, the leading edge of the preceding document has reached the discharge roller pair 119. , or the trailing edge of the preceding document has passed the read roller pair 115 . For this reason, the user pulls out the preceding document projecting from the discharge roller pair 119 by grasping the leading edge of the preceding document, or rotates the ADF 20 upward to pull out the preceding document from the open portion 180 (FIG. 14) of the ADF 20. Preceding documents can be easily removed. In this embodiment, the CPU 301 determines the position at which the preceding document should be removed based on the set value (L3 or L4) of the delay distance and the current position of the preceding document estimated from the driving pulse of the conveying motor 224. to display on the operation unit 90.

(Modification 1)
In Embodiments 1 to 3 described above, the transport motor 224 is an example of one motor (driving source) that drives a plurality of transport members in the image reading apparatus, and the number and arrangement of the transport rollers to be driven are limited to those illustrated. do not have. In addition to the transport motor 224, another motor for driving the pickup roller 111 and the feed roller 112 of the feeding unit 20F may be additionally arranged. In that case, the motor added to drive the feeding unit 20F starts and stops driving the feeding unit 20F while the transport motor 224 is driving the plurality of transport members (114, 115, 117, 119). It functions as a driving means capable of Even when a motor is added to drive the feeding unit 20F, the document spacing control described in the first to third embodiments is useful in a configuration in which the transport motor 224 drives a plurality of transport members. In that case, it is possible to apply Embodiments 1 to 3 by replacing the engagement of the feeding clutch 223 with "driving" of the added motor and the disengagement of the feeding clutch 223 with "stopping driving" of the added motor. can.

(Modification 2)
In Embodiments 1 to 3, the CPU 301 of the automatic document reading apparatus 10 acquires the length of the document being transported based on the detection timing of the leading edge and the trailing edge of the document by the post-separation sensor 207 and the driving pulse number of the transport motor 224. was That is, the CPU 301 functions as acquisition means for acquiring the length of the document. The acquisition means for acquiring the length of the document is not limited to this, and for example, a document length sensor for detecting the length of the document may be arranged on the document tray 121 . As an example, a document length sensor for detecting the presence or absence of a document on the document tray 121 is arranged at a position separated by a predetermined distance upstream from the pickup roller 111 in the sheet feeding direction. In this case, the CPU 301 can determine the document size by combining the detection results of the document length sensor and the sensor that detects the width of the side regulation plates 125A and 125B. Further, when the CPU 301 acquires from the operation unit 90 the document length input by the user's operation on the operation unit 90, the operation unit 90 functions as an acquisition unit.

(Modification 3)
In Embodiments 1 to 3, when L1<Lm, the conveying of the subsequent document is once stopped when the leading edge of the subsequent document is detected by the sensor 207 after separation. That is, the temporary stop position P (predetermined position) when the subsequent document is temporarily stopped is the position immediately after the leading edge of the subsequent document passes the detection position of the post-separation sensor 207 . However, the temporary stop position P may be any position upstream of the most upstream conveying member in the sheet conveying direction (registration roller pair 114 in Embodiments 1 to 3) among the plurality of conveying members driven by the conveying motor 224. Just do it. As a result, it is possible to continue the transport of the preceding document while causing the subsequent document to wait at the stop position P temporarily. Specifically, the temporary stop position P may be the position immediately before the leading edge of the succeeding document passes the post-separation sensor 207 and reaches the registration roller pair 114 .

Further, when the length of the document is determined in advance, the temporary stop position P can be the position of the separation nip. In this case, when L1<Lm, even if the post-separation sensor 207 detects the trailing edge of the preceding document, separation of the succeeding document is not started, and the leading edge of the preceding document reaches the discharge roller pair 119 or the trailing edge of the preceding document reaches the lead roller pair. After passing through 115, separation of subsequent documents is started. Note that, compared with this modified example, the first to third embodiments have the advantage that the throughput of the ADF 20 is improved by the amount that the temporary stop position P of the succeeding document is positioned downstream in the sheet conveying direction.

(Modification 4)
The control example described in the first to third embodiments is an example of a method of delaying the transport of the succeeding document when the length L1 of the document is shorter than the distance Lm from the cover opening 170 to the discharge roller pair 119. FIG. Regardless of the specific processing content of the control, as a result, when a document having a length L1 that satisfies L1<Lm is transported, an appropriate document interval can be ensured by delaying the transport of the succeeding document. The control method can be changed. For example, the threshold for determining whether or not to delay the transport of the succeeding document based on the length L1 of the document (S110, S210, S310) may not be Lm itself. For example, for standard-size documents, a determination may be made by referring to a table that predetermines whether or not to apply the delay distance (L3, L4) for each size.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

10: Image reading device (automatic document reading device) / 20: Second housing (ADF) / 40: First housing (reader unit) / 80: Control means (control circuit) / 104: Reading means (surface reading unit)/110A: cover portion (cover unit)/115: conveying roller pair (read roller pair)/119: discharge roller pair/120: placing portion (original stacking portion)/140: conveying path/170: opening (cover opening)/207: sensor (post-separation sensor)/223: driving means (feeding clutch)/224: motor (conveying motor)/L1: length of sheet/Lm: length from opening to discharge roller pair distance, first distance/Ls: second distance

Claims (10)

a placement section on which a sheet whose image information is to be read is placed;
a feeding unit having a separation section for separating sheets, and feeding the sheets while separating the sheets one by one from the stacking section;
a sensor arranged downstream of the separation unit in the sheet conveying direction and detecting the sheet;
a plurality of conveying members arranged along a sheet conveying path for conveying the sheet fed by the feeding unit;
a motor that drives the plurality of conveying members;
driving means capable of starting and stopping driving of the feeding unit while the plurality of conveying members are being driven by the motor;
a cover part configured to be able to open a part of the transport path;
a control means for controlling the motor and the driving means;
An image reading device having
the plurality of conveying members include a pair of discharge rollers for discharging the sheet from the conveying path;
The control means is
The length of the sheet fed from the placing section is a first length shorter than the distance along the conveying path from the opening of the conveying path to the pair of discharge rollers when the cover is open. In one case, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is kept waiting at a predetermined position. after reaching to the feeding unit to feed the succeeding sheet;
a length of the sheet fed from the stacking portion is a second length longer than a distance along the conveying path from an opening of the conveying path to the discharge roller pair when the cover is open; In one case, the trailing edge of the sheet following the feeding unit is arranged such that the distance between the trailing edge of the leading sheet and the leading edge of the following sheet is shorter than when the sheet of the first length is fed from the receiver. to feed the sheet,
An image reading device characterized by: a placement section on which a sheet whose image information is to be read is placed;
a feeding unit having a separation section for separating sheets, and feeding the sheets while separating the sheets one by one from the stacking section;
a sensor arranged downstream of the separation unit in the sheet conveying direction and detecting the sheet;
a plurality of conveying members arranged along a sheet conveying path for conveying the sheet fed by the feeding unit;
reading means for reading image information from a sheet conveyed on the conveying path;
a motor that drives the plurality of conveying members;
driving means capable of starting and stopping driving of the feeding unit while the plurality of conveying members are being driven by the motor;
a cover part configured to be able to open a part of the transport path;
a control means for controlling the motor and the driving means;
An image reading device having
a first housing in which the reading means is arranged;
A second housing, in which the plurality of conveying members are arranged and which can be opened and closed with respect to the first housing, wherein a sheet to be read by the reading means passes between the first housing and the first housing. a second housing provided with an open portion in which a part of the transport path is opened so as to form a space;
further having
the plurality of conveying members are a pair of conveying rollers disposed downstream of an opening of the conveying path and upstream of the open portion of the second housing in the sheet conveying direction when the cover is open; a pair of discharge rollers for discharging the sheet from the conveying path,
The control means is
The length of the sheet fed from the placing section is a first length shorter than the distance along the conveying path from the opening of the conveying path to the pair of discharge rollers when the cover is open. In one case, after the preceding sheet is fed by the feeding unit, the preceding sheet is conveyed by the plurality of conveying members while the succeeding sheet is kept waiting at a predetermined position. feeding the succeeding sheet to the feeding unit after passing through
a length of the sheet fed from the stacking portion is a second length longer than a distance along the conveying path from an opening of the conveying path to the discharge roller pair when the cover is open; In one case, the following sheet is fed to the feeding unit so that the distance between the trailing edge of the preceding sheet and the leading edge of the following sheet is shorter than when the sheet of the first length is fed from the receiver. An image reading device, characterized in that it feeds an image. a placement section on which a sheet whose image information is to be read is placed;
a feeding unit having a separation section for separating sheets, and feeding the sheets while separating the sheets one by one from the stacking section;
a sensor arranged downstream of the separation unit in the sheet conveying direction and detecting the sheet;
a plurality of conveying members arranged along a sheet conveying path for conveying the sheet fed by the feeding unit;
reading means for reading image information from a sheet conveyed on the conveying path;
a motor that drives the plurality of conveying members;
driving means capable of starting and stopping driving of the feeding unit while the plurality of conveying members are being driven by the motor;
a cover part configured to be able to open a part of the transport path;
a control means for controlling the motor and the driving means;
An image reading device having
a first housing in which the reading means is arranged;
A second housing, in which the plurality of conveying members are arranged and which can be opened and closed with respect to the first housing, wherein a sheet to be read by the reading means passes between the first housing and the first housing. a second housing provided with an open portion in which a part of the transport path is opened so as to form a space;
further having
the plurality of conveying members are a pair of conveying rollers disposed downstream of an opening of the conveying path and upstream of the open portion of the second housing in the sheet conveying direction when the cover is open; a pair of discharge rollers for discharging the sheet from the conveying path,
A distance along the transport path from an opening of the transport path to the pair of discharge rollers is defined as a first distance,
When the distance along the conveying path from the conveying roller pair to the discharging roller pair is defined as a second distance,
The control means is
When the length of the sheet fed from the tray is the first length that is equal to or greater than the second distance and less than the first distance, after the preceding sheet is fed by the feeding unit, the following sheet is fed. conveying the preceding sheet by the plurality of conveying members while the sheet is waiting at a predetermined position, and then feeding the succeeding sheet to the feeding unit after the leading edge of the preceding sheet reaches the pair of discharge rollers;
When the length of the sheet fed from the stacking portion is the second length that is less than the second distance, after the preceding sheet is fed by the feeding unit, the succeeding sheet is moved to the predetermined position. causing the preceding sheet to be conveyed by the plurality of conveying members while waiting at , and then feeding the succeeding sheet to the feeding unit after the trailing edge of the preceding sheet passes through the pair of conveying rollers;
When the length of the sheet fed from the receiver is a third length that is equal to or greater than the first distance, the sheet of the first length or the second length is fed from the receiver. causing the feeding unit to feed the succeeding sheet so that the distance between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet is shorter than when the sheet is fed;
An image reading device characterized by: The image reading device according to any one of claims 1 to 3,
the predetermined position is a position where the leading edge of the sheet is located downstream of the detection position of the sensor in the sheet conveying direction and upstream of the most upstream conveying member in the sheet conveying direction among the plurality of conveying members;
When causing the subsequent sheet to wait at the predetermined position, the control means drives the feeding unit to move the subsequent sheet to the predetermined position when the sensor detects that the trailing edge of the preceding sheet has passed. After that, the driving of the feeding unit is stopped and the succeeding sheet is made to wait at the predetermined position;
An image reading device characterized by: The image reading device according to any one of claims 1 to 4,
The control means is
When the succeeding sheet is not allowed to wait at the predetermined position, the feeding unit is driven based on the detection of the passage of the trailing edge of the preceding sheet by the sensor, and the succeeding sheet reaches the predetermined position. To feed subsequent sheets without stopping the drive of the unit,
An image reading device characterized by: The image reading device according to any one of claims 1 to 5,
The control means controls the amount of driving of the motor from when the sensor detects passage of the leading edge of the preceding sheet until when the sensor detects the passage of the trailing edge of the preceding sheet. to get the length of the sheet,
An image reading device characterized by: The image reading device according to any one of claims 1 to 6,
The drive means is a clutch that connects and disconnects drive transmission from the motor to the feeding unit based on instructions from the control means.
An image reading device characterized by: The image reading device according to any one of claims 1 to 6,
The driving means is another motor that is provided separately from the motor and drives the feeding unit.
An image reading device characterized by: The image reading device according to any one of claims 1 to 8,
When detecting a conveyance abnormality of the succeeding sheet after starting conveying the succeeding sheet waiting at the predetermined position, the control means does not continue the conveying of the preceding sheet and the succeeding sheet, and controls the feeding unit and the plurality of sheets. stop driving the conveying member of
An image reading device characterized by: an image reading device according to any one of claims 1 to 9;
an image forming unit that forms an image on a recording material based on image information read by the image reading device;
An image forming apparatus comprising:

Images