JP2011084399A - Sheet material carrying device, image reader and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet material carrying device, an image reader and an image forming device having the same capable of sufficiently narrowing a paper space more than a conventional paper space while preventing the double feeding of continuously-carried two sheet materials when carried up to a carrying object position one by one from a sheet material storage part for storing a plurality of sheet materials. <P>SOLUTION: An ADF 51 being the sheet material carrying device includes a tip detecting sensor S1 for transmitting a tip detecting signal to a controller when the tip is detected by detecting the tip in the carrying direction of a document MS carried in a predetermined position in a document carrying part 54, and the controller transmits a call-out starting signal to a sheet material call-out means such as a pickup roller 80 in predetermined timing based on the tip detecting signal. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a sheet material conveying apparatus that separates and conveys sheet materials one by one from a sheet material accommodating unit that accommodates a plurality of sheet materials, and an image reading apparatus and an image forming apparatus including the sheet material conveying apparatus. Is.

2. Description of the Related Art Conventionally, as an image reading device used as an image reading unit or a scanner of a copying machine, an image is read by a so-called sheet-through method in which a document image is read by image reading means fixed to the device while conveying a sheet-like document. There is something you can do by reading.
A sheet-through type image reading apparatus is a sheet material conveying apparatus that conveys a document one by one from a document table as a sheet material container for stacking and placing a plurality of documents to a reading position where a document image is read by an image reading unit. As an automatic document feeder. In such an automatic document feeder provided in such an image reading device, at least a part of two consecutively conveyed documents (hereinafter referred to as a previous document and a next document) overlaps when continuously reading the documents. Therefore, it is necessary to prevent double feeding.

  Conventional automatic document feeders include a document transport unit that transports a document to a reading position, and a document call that calls out one of a plurality of documents placed on a document table and sends it to the document transport unit. Some include a pickup roller as a member. This pick-up roller is driven to rotate in contact with the upper surface of one original on the top of a plurality of originals placed on the original table at a predetermined position in the transport direction on the original table. A conveyance force toward the document conveyance unit is applied to the one document. In such an automatic document feeder, the next document to be directed to the document transport unit together with the previous document is separated from the previous document so as to overlap the previous document with the conveying force applied to the pickup roller, and only the previous document is conveyed. A separating and conveying unit that conveys toward the unit. This separation conveyance unit conveys the originals one by one toward the original conveyance unit, thereby preventing double feeding.

Further, in the conventional automatic document feeder, when the leading edge of the previous document is detected by a sensor arranged at a predetermined position in the document feeder, the application of the feeding force by the pickup roller is stopped. Specifically, the pickup roller is separated from the upper surface of the document placed on the document table, or the rotation of the pickup roller is stopped. This is due to the following reason. That is, when the rear end of the previous document passes through a predetermined position in the transport direction where the pickup roller contacts the document placed on the document table, the pickup roller contacts the next document placed under the previous document. . At this time, the next original and the previous original remain overlapped between a predetermined position where the pickup roller contacts and the leading edge of the next original. Therefore, if the pickup roller continues to rotate even after the trailing edge of the previous document passes through a predetermined position where the pickup roller comes into contact, a part of the leading edge of the next document and a part of the trailing edge of the preceding document are separated. There is a possibility that a feeding force is applied to the next document in a state of being overlapped, which may cause double feeding.
After stopping the application of the conveyance force by the pickup roller, the previous document is conveyed by a conveyance member other than the pickup roller. Therefore, the application of the conveyance force by the pickup roller is stopped by the conveyance member other than the pickup roller. This is performed after the previous original reaches a position where it can be given.
In addition, when the pickup roller that has transported the previous document and stopped applying the transport force resumes applying the transport force to transport the next document, the previous document and the next document remain partially overlapped. When the application of the conveyance force is resumed, it causes double feeding. Therefore, the timing at which the next original is started to be conveyed by the pickup roller needs to be after the previous original is conveyed by a conveying member other than the pickup roller and the rear end of the previous original passes through the position where the front end of the next original exists. There is.

  The conventional automatic document feeder includes a trailing edge detection sensor that detects the trailing edge of the document on the downstream side in the conveyance direction with respect to the separation conveyance unit, and the trailing edge of the front document that has passed through the separation conveyance unit. There is one that starts the control of conveying the next original by the pickup roller, triggered by the detection of. With such a configuration, the timing at which the next original is started to be conveyed by the pickup roller is after the rear end of the previous original passes through a position where the front end of the next original is located, and double feeding can be prevented.

In order to improve productivity when continuously reading a document, an image reading device that reads a document image by feeding the document on the document table to the reading position one by one by such an automatic document feeder It is required to reduce the distance between the trailing edge of the original and the leading edge of the next original (hereinafter referred to as a sheet interval) as much as possible. However, as described above, when the calling operation is started with the detection of the trailing edge of the front document as a trigger, the interval between the sheets cannot be reduced so much. This is because if the trailing edge of the front document has passed through the separating and conveying section, the trailing edge of the preceding document may pass through the separating and conveying section even though the next document on the document table may be started immediately. This is because there is a time lag that is difficult to shorten from the time it passes through until the next document on the document table starts to be conveyed. Hereinafter, this time lag will be described.
When the conveyance of the next document by the pickup roller is triggered by the fact that the trailing edge of the previous document has passed the separation conveyance unit, the pickup roller drive motor starts after the trailing edge of the previous document has passed the separation conveyance unit In this case, the conveyance of the next document is not started. Further, in the configuration in which the pickup roller is separated from the upper surface of the document when the application of the conveyance force is stopped, the conveyance of the next document cannot be started until the separated pickup roller is moved to a position in contact with the document. Such a rise time of the calling operation such as the rise time of the drive motor and the time to move the pickup roller becomes a time lag that is difficult to shorten as described above. The distance that the previous document is conveyed during this time lag spreads the sheet as it is.

In order to reduce the influence of the time lag described above, it is conceivable to arrange the trailing edge detection sensor at a position where the passage of the trailing edge of the front document can be detected at the earliest possible timing. A position where the trailing edge of the front document passes at an earlier timing than before is upstream of the separation conveyance unit. As a configuration that can detect the passage of the trailing edge of the front document upstream from the separation conveyance unit, Patent Document 1 includes a roller member that contacts the upper surface of the bundle of documents on the document table, and changes in the speed of the roller member. A configuration is described in which the passage of the trailing edge of the front document is detected by detecting. However, in the configuration of Patent Document 1, a roller member that comes into contact with the upper surface of the original on the original plate protrudes further upstream than the pickup roller. There is a problem that it is not practical because it leads to a decrease.
In addition, the upstream side of the separation conveyance unit may be in a state where the next document is moved together with the previous document in a state where it overlaps the previous document. It is difficult to detect the passage of the trailing edge of the front document. Therefore, the position where the passage of the trailing edge of the front document can be detected is a position on the downstream side of the separation conveyance unit in which the separation of the previous document and the next document has been completed. There is a limit to advancing the detection timing of the trailing edge of the document.

  Japanese Patent Application Laid-Open No. 2004-228688 has a configuration in which the trailing edge of the previous document passes through the downstream side of the separation conveyance unit as a trigger for starting conveyance of the next document, and the document conveyance speed in the separation conveyance unit is set to A configuration in which the speed is set higher than the conveyance speed is described. With such a configuration, even if the gap between the sheets is widened when the next document starts to be transported, the next document transported through the separation transport unit when the previous document passes the reading position is Since the paper is transported at a speed faster than the transport speed, it is possible to narrow the gap between the papers spread by the time lag described above.

  However, with an increase in the conveyance speed at the reading position, it becomes difficult to provide a speed difference between the conveyance speed at the separation conveyance unit and the conveyance speed at the reading position so that the space between the papers spread by the time lag described above is sufficiently narrowed. Therefore, it is desired that the sheet interval at the time when the next document starts to be transported is made narrower than before.

In the automatic document feeder described in Patent Document 2, the call to the next document is detected after detecting that the trailing edge of the previous document, to which the conveyance force is applied by the document calling member, has passed the downstream position of the separating and conveying unit. Since the operation is started, the interval between the sheets is widened by the time lag of the rise time of the calling operation. The problem that the paper interval is widened due to the time lag of the rise time of the calling operation is not limited to the automatic document feeder in which the position where the passage of the trailing edge of the previous document is detected is the downstream position of the separating and conveying unit. The trailing edge detection sensor is placed at a position where it is possible to prevent double feeding even if the feeding force is applied to the next document, and control to carry the next document is triggered by the detection of the passage of the trailing edge of the previous document. The same problem may occur with an automatic document feeder that performs such a process.
Further, the problem that the paper interval is widened due to the time lag of the startup time of the call operation described above is not limited to the automatic document feeder, but from the sheet material storage unit that stores a plurality of sheet materials to the conveyance target position one by one. Any sheet material conveying device that conveys can occur.

  The present invention has been made in view of the above-described problems, and the object thereof is continuously conveyed when the sheet material is accommodated one by one from the sheet material accommodating portion that accommodates a plurality of sheet materials. By providing a sheet material conveying device capable of sufficiently narrowing the distance between sheets while preventing double feeding of two sheet materials, and an image reading apparatus and an image forming apparatus provided with the sheet material conveying device. is there.

In order to achieve the above object, the invention of claim 1 includes a sheet material accommodation unit that accommodates a plurality of sheet materials in a stacked manner, a sheet material conveyance unit that conveys the sheet material to a predetermined conveyance target position, and the sheet. A sheet material that calls a sheet material from a plurality of sheet materials by applying a conveying force toward the sheet material conveying unit side to the outermost sheet material of the plurality of sheet materials of the material container Separating from the one sheet material the calling means and another sheet material that overlaps with the one sheet material to which the conveying force is applied to the sheet material calling means and heads toward the sheet material conveying section, Separating means for directing only one sheet material to the sheet material conveying section, and sheet material calling control means for controlling the sheet material calling means, wherein the sheet material calling means is the sheet material calling control means. When a call start signal sent from It is a configuration that requires a predetermined rise time from the start of the calling operation for applying a conveying force to one sheet material and the start of conveying the one sheet material after the calling operation is started. After applying the conveying force to the one sheet material, the conveying force is applied by the sheet material calling means before the conveying force is applied to the next sheet material. In the sheet material conveying device to be stopped, the leading edge in the conveying direction of the sheet material conveyed at a predetermined position in the sheet material conveying unit is detected, and when the leading edge is detected, a leading edge detection signal is sent to the sheet material calling control means. The sheet material calling control means transmits the call start signal to the sheet material calling means at a predetermined timing based on the leading edge detection signal. is there.
According to a second aspect of the present invention, there is provided the sheet material conveying apparatus according to the first aspect, wherein the sheet material length information, which is information on a length in the conveying direction of the sheet material accommodated in the sheet material accommodating portion, is called up the sheet material. Sheet material length information input means for inputting to the control means, and the sheet material call control means outputs the call start signal to the sheet material call means based on the leading edge detection signal and the sheet material length information. It is characterized by transmitting.
Further, the invention of claim 3 is the sheet material conveying apparatus according to claim 2, wherein the sheet material length information input means detects the length in the conveying direction of the sheet material accommodated in the sheet material accommodating portion. A length detecting means is provided.
According to a fourth aspect of the present invention, there is provided the sheet material conveying apparatus according to the second or third aspect, wherein the sheet material is conveyed at a predetermined position downstream in the conveying direction of the sheet material from the region where the separating action of the separating means works. A rear end detection unit that detects a rear end of the sheet in the conveying direction and transmits a rear end detection signal to the sheet material call control unit when the rear end is detected. Based on the material length information, when it is determined that the length in the conveyance direction of the sheet material accommodated in the sheet material accommodating portion is within a predetermined range, a predetermined timing after receiving the tip detection signal When the call start signal is transmitted to the sheet material calling means and it is determined that the length of the sheet material accommodated in the sheet material accommodating portion is outside the predetermined range, the trailing edge detection signal After receiving the predetermined timin In which characterized in that transmitting the call start signal to the sheet material calling means.
According to a fifth aspect of the present invention, in the sheet material conveying apparatus according to any one of the second to fourth aspects, the leading end in the conveying direction of the sheet material conveyed at a plurality of positions in the sheet conveying portion is detected. A plurality of the leading edge detection means are provided so that the sheet material calling control means selects one of the plurality of leading edge detection means based on the sheet material length information, and the selected leading edge detection means The call start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the leading edge detection signal.
According to a sixth aspect of the present invention, in the sheet material conveying apparatus according to any one of the second to fourth aspects, the sheet material calling control unit includes a storage unit that stores a plurality of pieces of information on the predetermined timing. The sheet material call control means selects one of a plurality of predetermined timings based on the sheet material length information, and starts the calling at the selected predetermined timing after receiving the leading edge detection signal. A signal is transmitted to the sheet material calling means.
Further, the invention of claim 7 is the sheet material conveying apparatus according to any one of claims 1 to 6, wherein the sheet material calling means is a plurality of sheets accommodated overlapping the sheet material accommodating portion. A sheet material calling member that applies a conveying force to the one sheet material by driving in contact with the outermost sheet material, and the sheet material calling member is placed in the sheet material accommodating portion. A sheet material calling member contacting / separating mechanism for contacting or separating the sheet material, and when the sheet material calling means receives the call start signal, the sheet material calling member contacting / separating mechanism as the calling operation An operation of bringing the sheet material calling member into contact with the sheet material in the sheet material housing portion and an operation of driving the sheet material calling member in contact with the sheet material are performed.
The invention according to claim 8 is the sheet material conveying apparatus according to any one of claims 1 to 6, wherein the leading edge detection means detects the leading edge of the sheet material rather than the leading edge detection position. A leading end in the conveying direction of the sheet material conveyed at a predetermined position in the upstream sheet material conveying unit is detected, and when this leading end is detected, an upstream leading end detection signal is transmitted to the sheet material calling control means. The sheet material calling means is driven in a state of being in contact with the outermost one sheet material of the plurality of sheet materials accommodated to overlap the sheet material accommodating portion. A sheet material calling member for applying a conveying force; and a sheet material calling member contacting / separating mechanism for bringing the sheet material calling member into contact with or separating from the sheet material in the sheet material accommodating portion. Transmits a call preparation signal for performing a preparatory operation prior to the calling operation to the sheet material calling means at a predetermined timing based on the upstream side leading edge detection signal, and the sheet material calling means transmits the call preparation signal. Is received, the sheet material calling member contacting / separating mechanism performs an operation of bringing the sheet material calling member into contact with the sheet material in the sheet material accommodating portion as the preparation operation, and the sheet material calling means performs the calling operation. When a start signal is received, an operation for driving the sheet material calling member that has contacted the sheet material is executed as the calling operation.
The invention according to claim 9 is the sheet material conveying apparatus according to any one of claims 1 to 8, wherein the sheet material calling means is a plurality of sheets accommodated in the sheet material accommodating portion. A sheet material calling member that applies a conveying force by driving in a state in contact with the outermost sheet material of the material, and when the sheet material calling means receives the call start signal, An operation of driving the sheet material calling member in contact with the sheet material is executed.
The invention of claim 10 is the sheet material feeding device according to claim 9, wherein the sheet material calling means makes the sheet material calling member come into contact with or separate from the sheet material in the sheet material accommodating portion. A member contact / separation mechanism is provided.
The invention according to claim 11 is the sheet material conveying apparatus according to claim 10, wherein when the sheet material calling means receives the call start signal, the sheet material calling member contacting / separating mechanism is operated as the sheet material. An operation of bringing the calling member into contact with the sheet material in the sheet material accommodating portion and an operation of driving the sheet material calling member in contact with the sheet material are performed.
The invention of claim 12 is the sheet material conveying apparatus according to any one of claims 1 to 11, wherein a predetermined position downstream of the sheet material conveying direction from the region where the separating action of the separating means works. A rear end detection unit that detects a rear end of the sheet material conveyed in the direction of the sheet material, and transmits a rear end detection signal to the sheet material call control unit when the rear end is detected; and separation of the separation unit And a double feed detecting means for detecting whether or not the double feed of the sheet material is generated in the vicinity of the region where the action is applied. When detected, the calling start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the trailing edge detection signal.
According to a thirteenth aspect of the present invention, in the sheet material conveying apparatus according to the twelfth aspect of the invention, the double feed detecting means is an ultrasonic detection sensor.
According to a fourteenth aspect of the present invention, in the sheet material conveying apparatus according to the twelfth aspect, the double feed detecting means is a light transmission type detection sensor.
According to a fifteenth aspect of the present invention, there is provided an image reading apparatus comprising: a document conveying unit that conveys a document sheet as a sheet material; and a reading unit that reads a document image of the document sheet conveyed by the document conveying unit. The sheet material conveying device according to any one of claims 1 to 14 is used as the document conveying means.
According to a sixteenth aspect of the present invention, there is provided an image forming apparatus comprising: an image reading unit; and an image forming unit that forms an image based on a document image read by the image reading unit. The image reading apparatus is provided.

In the present invention, the sheet material calling control means detects the leading edge of the front sheet material of the two sheet materials (hereinafter referred to as the front sheet material and the next sheet material) conveyed in succession by the leading edge detection means. Based on the leading edge detection signal, a call start signal for conveying the next sheet material at a predetermined timing is transmitted to the sheet material calling means. For this reason, unlike the case where the detection means for detecting the passage of the sheet material detects the trailing edge of the front sheet material as a trigger, the position before the trailing edge of the front sheet material reaches the position detected by the detection means. It is possible to set a trigger for starting the calling operation for the next sheet material at an earlier timing than before. As a result, the conveyance of the next original is compared to the conventional configuration in which the subsequent sheet material starts to be conveyed after the rising time has elapsed after the trailing edge of the previous sheet material has reached the position detected by the detection unit. The time lag after the start is possible can be shortened.
Further, the timing at which a predetermined rising time has elapsed after the sheet material calling means receives the calling signal is set to be the timing after the rear end of the front sheet material has reached a position where the occurrence of the multifeed can be prevented. By setting a predetermined timing at which the sheet material call control means transmits the call start signal, it is possible to prevent occurrence of double feed.

  According to the present invention, there is an excellent effect that it is possible to narrow the space between sheets by shortening the time lag compared to the conventional one while preventing double feeding of two sheet materials conveyed continuously. .

1 is a schematic configuration diagram illustrating an ADF of an embodiment together with an upper part of a scanner. 1 is a schematic configuration diagram showing a copier according to an embodiment. FIG. 2 is a partial configuration diagram illustrating an enlarged part of an image forming unit in the copier. FIG. 3 is a partially enlarged view showing a part of a tandem part composed of four process units in the image forming part. FIG. 2 is a perspective view showing a scanner and an ADF of the copier. The control block diagram of the whole ADF51. The control part block diagram of a fixed image reading part. 1 is a schematic explanatory diagram of an ADF according to Embodiment 1. FIG. FIG. 3 is a schematic explanatory diagram of a configuration in which the target length sensor includes two sensors in the configuration of the ADF according to the first embodiment. FIG. 4 is an explanatory diagram of timing at which the conveyance of a previous document is started by rotation of a pickup roller in the ADF according to the first exemplary embodiment. FIG. 6 is an explanatory diagram of timing immediately before the previous document conveyed by the rotation of the pickup roller enters the separation nip portion in the ADF according to the first exemplary embodiment. FIG. 4 is an explanatory diagram of timings at which the pickup roller starts to rise in the ADF according to the first embodiment. FIG. 6 is an explanatory diagram of timing when the leading edge of the previous document is detected by the leading edge detection sensor in the ADF according to the first exemplary embodiment. FIG. 6 is an explanatory diagram of timing at which the pickup roller descends in the ADF according to the first embodiment. FIG. 4 is an explanatory diagram of timing at which the next document is started to be conveyed by rotation of a pickup roller in the ADF according to the first exemplary embodiment. 3 is a timing chart showing driving timing of each motor in the ADF according to the first embodiment. The schematic explanatory drawing of ADF of a modification. FIG. 10 is an explanatory diagram of timing when the leading edge of the previous document is detected by the leading edge detection sensor in a state where double feeding occurs in the separation nip portion of the ADF according to the modification. Explanatory drawing of the timing when the pick-up roller finished the descent in the state where double feeding occurred in the separation nip portion of the ADF of the modified example. FIG. 9 is an explanatory diagram of timing at which conveyance of a next original is started by rotation of a pickup roller after double feeding occurs in a separation nip portion of an ADF according to a modified example. FIG. 10 is an explanatory diagram of timing at which the conveyance of a previous document is started by rotation of a pickup roller in the ADF according to the second embodiment. FIG. 10 is an explanatory diagram of timing at which the pair of pull-out rollers starts to rotate after the front document hits in the ADF according to the second embodiment. FIG. 6 is an explanatory diagram of timing at which the pickup roller descends in the ADF according to the second embodiment. 9 is a timing chart showing driving timing of each motor in the ADF according to the second embodiment. Explanatory drawing of the structure which has arrange | positioned the double feed detection sensor to ADF of Example 2. FIG. The flowchart of control which determines the trigger of the calling operation of the structure which performs a calling operation immediately after the front-end | tip detection of a front-end | tip detection sensor. FIG. 26 is a flowchart of control for determining a trigger for starting conveyance of the next document having the ADF configuration shown in FIG. 25; Explanatory drawing of the timing which the fall of the pickup roller was completed in ADF of Example 3. FIG. FIG. 10 is an explanatory diagram of timing at which conveyance of the next original is started by rotation of a pickup roller in the ADF according to the third exemplary embodiment. The flowchart of the control which determines the trigger of the calling operation of the structure which performs a calling operation after only predetermined time passes, after the front-end | tip detection of a front-end | tip detection sensor. Explanatory drawing of the structure which has arrange | positioned the double feed detection sensor to ADF of Example 3. FIG. FIG. 32 is a control flowchart for determining a trigger for starting the calling operation of the configuration of the ADF shown in FIG. 31. FIG. 6 is a schematic explanatory diagram of an ADF according to a fourth embodiment. 10 is a flowchart of control for determining a trigger for a call operation in the ADF according to the fourth embodiment. Explanatory drawing of the structure which has arrange | positioned the double feed detection sensor to ADF of Example 4. FIG. FIG. 36 is a flowchart of control for determining a trigger for starting the conveyance of the next document having the ADF configuration shown in FIG. FIG. 7 is a schematic explanatory diagram of an ADF according to a fifth embodiment. 10 is a flowchart of control for determining a trigger for a call operation in the ADF according to the fifth embodiment. Explanatory drawing of the structure which has arrange | positioned the double feed detection sensor to ADF of Example 5. FIG. FIG. 40 is a flowchart of control for determining a trigger for starting conveyance of the next document having the ADF configuration shown in FIG. FIG. 10 is a schematic explanatory diagram of an ADF of Example 6. 10 is a flowchart of control for determining a trigger for a call operation in the ADF according to the sixth embodiment. Explanatory drawing of the structure which has arrange | positioned the double feed detection sensor in ADF of Example 6. FIG. FIG. 44 is a flowchart of control for determining a trigger for starting the calling operation of the configuration of the ADF shown in FIG. 43. FIG. FIG. 6 is an explanatory diagram of timing immediately before the conveyance of a previous document is started and a separation nip portion is entered in the ADF of the comparative example. FIG. 6 is an explanatory diagram of timing at which the leading edge of a previous document passes through a separation nip portion in an ADF of a comparative example. Explanatory drawing of the timing which the raise of a pick-up roller finished in ADF of a comparative example. Explanatory drawing of the timing which the fall of a pick-up roller finished in ADF of a comparative example. FIG. 9 is an explanatory diagram of timing immediately before the next document starts to be conveyed and enters the separation nip portion in the ADF of the comparative example.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as a copying machine 500) will be described.
First, a basic configuration of the copying machine 500 according to the present embodiment will be described.
FIG. 2 is a schematic configuration diagram showing the copying machine 500. This copying machine includes an image forming unit 1 as an image forming apparatus, a transfer paper supply device 40, and an image reading unit 50. The image reading unit 50 as an image reading apparatus includes a scanner 150 fixed on the image forming unit 1 and an automatic document feeder (hereinafter referred to as ADF) 51 as a sheet conveying device supported by the scanner 150. ing.

  The transfer paper supply device 40 includes two transfer paper feed cassettes 42 arranged in multiple stages in the paper bank 41, a transfer paper feed roller 43 that feeds transfer paper from the transfer paper feed cassette 42, and the transferred transfer paper. A transfer paper separation roller 45 and the like that are separated and supplied to the transfer paper feed path 44 are provided. In addition, the main body side transfer paper feed path 37 as a transport path of the image forming unit 1 also includes a plurality of transport rollers 47 for transporting transfer paper as a sheet-like member. Then, the transfer paper in the transfer paper feed cassette 42 is fed into the main body side transfer paper feed path 37 in the image forming unit 1.

  The image forming unit 1 as an image forming unit includes an optical writing device 2 and four process units 3K, Y, M, and 4 that form toner images of black, yellow, magenta, and cyan (K, Y, M, and C). C, a transfer unit 24, a paper transport unit 28, a registration roller pair 33, a fixing device 34, a switchback device 36, a main body side transfer paper feed path 37, and the like. Then, a light source such as a laser diode or LED (not shown) disposed in the optical writing device 2 is driven to irradiate the four drum-shaped photosensitive members 4K, Y, M, and C with the laser light L. . By this irradiation, electrostatic latent images are formed on the surfaces of the photoreceptors 4K, Y, M, and C, and the latent images are developed into toner images via a predetermined development process.

  FIG. 3 is a partial configuration diagram illustrating an enlarged part of the internal configuration of the image forming unit 1. FIG. 4 is a partially enlarged view showing a part of a tandem part composed of four process units 3K, Y, M, and C. The four process units 3K, Y, M, and C have substantially the same configuration except that the colors of the toners to be used are different. Therefore, the subscripts K, Y, M, and C attached to the respective reference numerals in FIG. Is omitted.

  The process units 3K, 3Y, 3C, and 3C support the photosensitive member and the various devices disposed around it as a single unit on a common support, and with respect to the image forming unit 1 main body. Detachable. One process unit 3 includes a charging device 5, a developing device 6, a drum cleaning device 15, a charge removal lamp 22, and the like around the photoconductor 4. The copying machine 500 has a so-called tandem type configuration in which four process units 3K, Y, M, and C are arranged so as to face an intermediate transfer belt 25 described later along the endless movement direction. Yes.

  As the photoreceptor 4, a drum-shaped member is used in which a photosensitive layer is formed by applying a photosensitive organic photosensitive material to a base tube made of aluminum or the like. However, an endless belt may be used.

  The developing device 6 develops the latent image using a two-component developer containing a magnetic carrier and a nonmagnetic toner (not shown). In order to transfer the toner in the two-component developer carried on the developing sleeve 12 to the photosensitive member 4, the agitating unit 7 that conveys the two-component developer accommodated in the inside and supplies the developing sleeve 12 with stirring. Development section 11.

  The stirring unit 7 is provided at a position lower than the developing unit 11, and is provided on the bottom surface of the two conveying screws 8 arranged in parallel to each other, a partition plate provided between these screws, and the developing case 9. The toner density sensor 10 is included.

  The developing unit 11 includes a developing sleeve 12 that faces the photosensitive member 4 through the opening of the developing case 9, a magnet roller 13 that is non-rotatably provided inside the developing sleeve 12, a doctor blade 14 that approaches the developing sleeve 12, and the like. ing. The developing sleeve 12 has a non-magnetic rotatable cylindrical shape. The magnet roller 13 has a plurality of magnetic poles that are sequentially arranged from the position facing the doctor blade 14 toward the rotation direction of the developing sleeve 12. Each of these magnetic poles applies a magnetic force to the two-component developer on the developing sleeve 12 at a predetermined position in the rotational direction. As a result, the two-component developer sent from the stirring unit 7 is attracted and carried on the surface of the developing sleeve 12 and a magnetic brush is formed on the surface of the developing sleeve 12 along the lines of magnetic force.

  The magnetic brush is regulated to an appropriate layer thickness when passing through the position facing the doctor blade 14 as the developing sleeve 12 rotates, and then conveyed to the developing region facing the photoconductor 4. Then, the toner is transferred onto the electrostatic latent image by the potential difference between the developing bias applied to the developing sleeve 12 and the electrostatic latent image on the photosensitive member 4, thereby contributing to development. Further, the two-component developer that forms a magnetic brush and is carried by the developing sleeve 12 and passes through the developing region returns to the developing unit 11 again as the developing sleeve 12 rotates, and is formed between the magnetic poles of the magnet roller 13. After being separated from the sleeve surface due to the influence of the repulsive magnetic field, the magnetic field is returned to the stirring unit 7. An appropriate amount of toner is supplied to the two-component developer in the stirring unit 7 based on the detection result of the toner density sensor 10. As the developing device 6, a device using a one-component developer not containing a magnetic carrier may be adopted instead of a device using a two-component developer.

  As the drum cleaning device 15, a system in which the cleaning blade 16 made of an elastic body is pressed against the photoconductor 4 is used, but another system may be used. For the purpose of enhancing the cleaning property, this example employs a system having a contact conductive fur brush 17 whose outer peripheral surface is in contact with the photoreceptor 4 so as to be rotatable in the direction of the arrow in the figure. The fur brush 17 also serves to apply the lubricant to the surface of the photosensitive member 4 while scraping the lubricant from a solid lubricant (not shown) into a fine powder. A metal electric field roller 18 for applying a bias to the fur brush 17 is rotatably provided in the direction of the arrow in the figure, and the tip of the scraper 19 is pressed against it. The toner attached to the fur brush 17 is transferred to the electric field roller 18 to which a bias is applied while rotating in contact with the fur brush 17 in the counter direction. Then, after being scraped from the electric field roller 18 by the scraper 19, it falls onto the recovery screw 20. The collection screw 20 conveys the collected toner toward the end of the drum cleaning device 15 in the direction orthogonal to the drawing surface, and delivers it to the external recycling conveyance device 21. The recycle conveyance device 21 sends the collected toner that has been delivered to the developing device 6 for recycling.

  The neutralization lamp 22 neutralizes the surface of the photoreceptor 4 by light irradiation. The surface of the photoreceptor 4 that has been neutralized is uniformly charged by the charging device 5 and then subjected to optical writing processing by the optical writing device 2. In the copying machine 500, the charging device 5 is a device in which a charging roller to which a charging bias is applied is rotated while being in contact with the photoconductor 4, but a scorotron that performs a charging process on the photoconductor 4 in a non-contact manner. A charger or the like may be used.

  In FIG. 3 described above, K, Y, M, and C toner images are formed on the photoreceptors 4K, Y, M, and C of the four process units 3K, Y, M, and C by the processes described above. Is done.

  A transfer unit 24 is disposed below the four process units 3K, Y, M, and C. The transfer unit 24 moves the intermediate transfer belt 25 stretched by a plurality of rollers endlessly in the clockwise direction in the drawing while contacting the photoreceptors 4K, Y, M, and C. As a result, primary transfer nips for K, Y, M, and C in which the photoreceptors 4K, Y, M, and C contact the intermediate transfer belt 25 are formed. In the vicinity of the primary transfer nips for K, Y, M, and C, the intermediate transfer belt 25 is transferred to the photoreceptors 4K, Y, M, and C by primary transfer rollers 26K, Y, M, and C disposed inside the belt loop. It is pushing toward. A primary transfer bias is applied to the primary transfer rollers 26K, Y, M, and C by a power source (not shown). As a result, a primary transfer electric field for electrostatically moving the toner images on the photoreceptors 4K, Y, M, and C toward the intermediate transfer belt 25 is formed in the primary transfer nips for K, Y, M, and C. Yes. In the drawing, a toner image is sequentially formed at each primary transfer nip on the front surface of the intermediate transfer belt 25 that sequentially passes through the primary transfer nips for K, Y, M, and C along with the endless movement in the clockwise direction. Overlaid and primary transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) is formed on the front surface of the intermediate transfer belt 25.

  Below the transfer unit 24 in the figure, a paper transport unit 28 is provided between the drive roller 30 and the secondary transfer roller 31 to endlessly move the endless paper transport belt 29. The intermediate transfer belt 25 and the paper transport belt 29 are sandwiched between the secondary transfer roller 31 and the lower stretching roller 27 of the transfer unit 24. As a result, a secondary transfer nip is formed in which the front surface of the intermediate transfer belt 25 and the front surface of the paper transport belt 29 abut. A secondary transfer bias is applied to the secondary transfer roller 31 by a power source (not shown). On the other hand, the lower stretching roller 27 of the transfer unit 24 is grounded. Thereby, a secondary transfer electric field is formed in the secondary transfer nip.

  A registration roller pair 33 is disposed on the right side of the secondary transfer nip in the drawing. A registration roller sensor (not shown) is disposed near the entrance of the registration nip of the registration roller pair 33. The transfer paper P conveyed from the transfer paper supply device 40 toward the registration roller pair 33 temporarily stops the transfer of the transfer paper P after a predetermined time when the leading edge of the transfer paper P is detected by a registration roller sensor (not shown). The tip is brought into contact with the resist nip of the pair 33. As a result, the posture of the transfer paper P is corrected, and preparations for synchronization with image formation are completed.

  When the prior application of the transfer paper P hits the registration nip, the registration roller pair 33 resumes roller rotation driving at a timing at which the transfer paper P can be synchronized with the four-color toner image on the intermediate transfer belt 25, and the transfer paper P To the secondary transfer nip. In the secondary transfer nip, the four-color toner images on the intermediate transfer belt 25 are collectively transferred to the transfer paper P due to the influence of the secondary transfer electric field and the nip pressure, and combined with the white color of the transfer paper P, a full color image is formed. The transfer paper P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 25 and is conveyed to the fixing device 34 along with its endless movement while being held on the front surface of the paper conveyance belt 29.

  The transfer residual toner that has not been transferred to the transfer paper P at the secondary transfer nip is attached to the front surface of the intermediate transfer belt 25 that has passed through the secondary transfer nip. The transfer residual toner is scraped and removed by the belt cleaning device 32 in which the cleaning member contacts the intermediate transfer belt 25.

  The transfer paper P conveyed to the fixing device 34 is fixed to a full-color image by pressurization or heating in the fixing device 34, and then sent from the fixing device 34 to the paper discharge roller pair 35. The paper is discharged to a paper discharge tray 501.

  In FIG. 2 described above, below the paper transport unit 28 and the fixing device 34, a switchback device 36 which is a transfer paper reversing device is disposed. As a result, when performing double-sided printing, the transfer path of the transfer paper P that has undergone image fixing processing on one side is switched to the switchback device 36 side by the switching claw, and is reversed there to return to the secondary transfer transfer nip. enter in. Then, after the secondary transfer process and the fixing process of the image are performed on the other side, the sheet is discharged onto the discharge tray 501.

  The image reading unit 50 including the scanner 150 fixed on the image forming unit 1 and the ADF 51 fixed on the image forming unit 1 includes a fixed reading unit and a moving reading unit 152. The movable reading unit 152 is disposed directly below the second contact glass 155 fixed to the upper wall of the casing of the scanner 150 so as to come into contact with the document MS, and shows an optical system including a light source, a reflection mirror, and the like. It can be moved in the left-right direction. Then, in the process of moving the optical system from the left side to the right side in the figure, the light emitted from the light source is reflected by the lower surface of the document MS (not shown) placed on the second contact glass 155, and then a plurality of reflections are made. Light is received by the image reading sensor 153 fixed to the scanner 150 via the mirror.

  On the other hand, the image reading unit 50 includes, as fixed reading units, a first fixed reading unit 151 disposed in the scanner 150 and a second fixed reading unit 95 described later disposed in the ADF 51. . A first fixed reading unit 151 having a light source, a reflection mirror, an image reading sensor such as a CCD, etc. is disposed immediately below a first contact glass 154 fixed to the upper wall of the casing of the scanner 150 so as to contact the document MS. ing. Then, when the document MS conveyed by the ADF 51 passes over the first contact glass 154, image reading is performed via a plurality of reflecting mirrors while sequentially reflecting the light emitted from the light source on the first surface of the document MS. The sensor 153 receives light. Accordingly, the first surface of the document MS is scanned without moving the optical system including the light source and the reflection mirror. The second fixed reading unit 95 scans the second surface of the document MS after passing through the first fixed reading unit 151.

  An ADF 51 disposed on the scanner 150 includes a document placing table 53 for placing a document MS before reading on a main body cover 52, a document transporting unit 54 for transporting a document MS as a sheet material, and a reading. A document stacking table 55 for stacking the subsequent document MS is held. As shown in FIG. 5, it is supported by a hinge 159 fixed to the scanner 150 so as to be swingable in the vertical direction. Then, by swinging, it moves like an open / close door, and the first contact glass 154 and the second contact glass 155 on the upper surface of the scanner 150 are exposed in the opened state. In the case of a single-bound document such as a book in which one corner of a document bundle is bound, the documents cannot be separated one by one, and therefore cannot be transported by the ADF 51. Therefore, in the case of a single-sided original, the ADF 51 is opened as shown in FIG. 5, the single-sided original with the page to be read open is placed face down and placed on the second contact glass 155, and then the ADF 51 is placed. close. Then, the image of the page is read by the moving reading unit 152 shown in FIG.

  On the other hand, in the case of a document stack in which a plurality of independent documents MS are simply stacked, the documents MS are automatically conveyed one by one by the ADF 51 while the first fixed reading unit 151 in the scanner 150 and the second fixed document in the ADF 51 are used. The fixed reading unit 95 can sequentially read. In this case, after the original bundle is set on the original placement table 53, the copy start button 158 of the operation unit 108 is pressed. Then, the ADF 51 sends the document MS of the bundle of documents placed on the document placement table 53 in order from the top into the document conveyance unit 54 and conveys the document MS toward the document stacking table 55 while inverting it. In the course of this conveyance, immediately after the original MS is reversed, it passes through the first fixed reading unit 151 of the scanner 150. At this time, the image on the first surface of the document MS is read by the first fixed reading unit 151 of the scanner 150.

Next, the ADF 51 will be described.
FIG. 1 is an enlarged configuration diagram showing the main configuration of the ADF 51 together with the upper portion of the scanner 150. The ADF 51 includes a document setting unit A, a separation conveyance unit B, a registration unit C, a turn unit D, a first reading conveyance unit E, a second reading conveyance unit F, a paper discharge unit G, a stack unit H, and the like. The document transport section 54 of the ADF 51 according to the present embodiment is a portion constituting a path through which the document MS is transported from the detection position by the separation sensor S3 on the downstream side of the separation transport section B to the reading entrance roller pair 90.

  The document setting unit A includes a document placement table 53 on which a bundle of documents MS is set so that the first surface is upward. The separation conveyance unit B separates and feeds the originals MS one by one from the set of originals MS set. The registration unit C temporarily abuts on the fed document MS and aligns the document MS to send it out. The turn portion D has a curved conveyance portion that is curved in a C shape, and the document MS is turned upside down while being folded in the curved conveyance portion, so that the first surface of the original MS is directed downward. . The first reading and conveying unit E conveys the document MS on the first contact glass 154, while the document MS is transferred from the lower side of the first contact glass 154 to the first fixed reading unit 151 disposed in the scanner 150. The first side is read. The second reading conveyance unit F causes the second fixed reading unit 95 to read the second surface of the document MS while conveying the document MS by a second reading roller 96 disposed below the second fixed reading unit 95. It is. The paper discharge unit G discharges the original MS from which both-side images are read toward the stack unit H. The stack unit H stacks the document MS on the document stacking table 55.

  FIG. 6 is a control block diagram of the entire ADF 51. The control unit of the ADF 51 includes motors 101 to 105 and 113 to 115 that are driving units for driving a document conveying operation, various sensor units, and a fixed image reading unit 300 (first fixed reading unit 151 or second fixed reading unit). 95), and the controller 100 for controlling a series of operations.

  FIG. 7 is a control unit block diagram of the fixed image reading unit 300. The fixed image reading unit 300 includes a light source unit 200, a sensor chip 201, an image processing unit 204, a frame memory 205, an output control circuit 206, and the like.

A document MS to be read includes a movable document table 53b that supports the leading edge of the document and can swing in the directions of arrows a and b according to the thickness of the bundle of documents MS, and a fixed document table that supports the trailing edge of the document. 53a is set on the document placing table 53 composed of 53a with the first surface facing upward. At this time, side guides (not shown) are abutted on both ends of the document placement table 53 in the width direction (the direction perpendicular to the conveyance direction of the document MS and the direction perpendicular to the drawing sheet). Positioning in the direction is made.
The document MS set on the document table 53 in this way pushes up the set filler 62 that is a lever member that is swingably disposed above the movable document table 53b. Accordingly, the document set sensor 63 detects the setting of the document MS and transmits a detection signal to the controller 100. The detection signal is transmitted from the controller 100 to the main body control unit 111 of the image reading unit 50 via an interface circuit (hereinafter referred to as I / F 107).

  The fixed document table 53a includes a plurality of document length sensors (S4, 57, S4, 57, S4, 57, S5, S5, S5, S5, S5, and S5) that include a reflective photosensor that detects the length of the document MS in the conveyance direction. 58a, 58b) are arranged. These document length sensors determine the outline of the length of the document MS in the transport direction (requires at least a sensor arrangement that can determine whether the document size is vertical or horizontal).

A pickup roller 80 is disposed above the movable document table 53b.
The movable document table 53b is swung in the directions of arrows a and b in the drawing by the driving cam mechanism by the driving of the bottom plate raising motor 105. When the set filler 62 and the document set sensor 63 detect that the document MS is set on the document placement table 53, the controller 100 rotates the bottom plate raising motor 105 in the normal direction so that the uppermost surface of the bundle-shaped document MS becomes the pickup roller 80. The movable document table 53b is raised so as to come into contact.
The pickup roller 80 is movable in the directions of arrows c and d in the figure by a cam mechanism driven by the pickup lifting / lowering motor 101. Further, the pick-up roller 80 is raised in the direction of arrow c in the figure by moving the movable original table 53b and being pushed by the upper surface of the original MS on the movable original table 53b. By detecting this by the table lift sensor 59, the lift to the upper limit of the movable document table 53b is detected. As a result, the pickup raising / lowering motor 101 stops and the bottom plate raising motor 105 stops.

  A copy start button 158 is pressed from the operation unit 108, and a document feed signal is transmitted from the main body control unit 111 to the controller 100 which is a control unit of the ADF 51 via the I / F 107. As a result, the pickup conveyance motor 115 is driven and the pickup roller 80 is rotationally driven to pick up several (ideally one) originals MS on the original placement table 53. The rotation direction of the pickup roller 80 is a direction in which the uppermost document MS is conveyed to the paper feed port 48.

The document MS sent out by the pickup roller 80 enters the separation conveyance unit B and is sent to a contact position with the paper feed belt 84. The paper feed belt 84 is stretched around a drive roller 82 and a driven roller 83, and is endlessly moved in the clockwise direction in the drawing by the rotation of the drive roller 82 accompanying the forward rotation of the paper feed motor 102.
A reverse roller 85 that is driven to rotate in the clockwise direction in the drawing by the forward rotation of the paper feed motor 102 is in contact with the lower tension surface of the paper feed belt 84. At the contact portion, the surface of the paper feed belt 84 moves in the paper feed direction. On the other hand, the surface of the reverse roller 85 tries to move in the direction opposite to the paper feeding direction, but the drive transmission portion of the reverse roller 85 has a torque limiter (not shown), and the force toward the paper feeding direction is torque. When the torque is larger than the limiter torque, the reverse roller 85 rotates so as to move the surface in the sheet feeding direction. The reverse roller 85 is in contact with the paper feeding belt 84 at a predetermined pressure, and when the reverse roller 85 is in direct contact with the paper feeding belt 84 or when only one document MS is sandwiched in the contact portion, Along with the paper feed belt 84 or the document MS. However, when a plurality of documents MS are sandwiched between the contact portions, the rotation force is set to be lower than the torque of the torque limiter. To rotate. As a result, a moving force in the direction opposite to the feeding direction is applied to the original document MS below the uppermost position by the reverse roller 85, and only the uppermost original document MS is separated from several originals. Thereby, double feeding is prevented.

The document MS separated into one sheet by the action of the sheet feeding belt 84 and the reverse roller 85 enters the registration portion C. Then, the paper is further fed by the paper feed belt 84 and is further abutted against the pull-out roller pair 86 that is stopped while being detected by the abutting sensor 72. Thereafter, the paper feed motor 102 is driven for a predetermined time from the detection of the tip by the abutting sensor 72 and stopped. As a result, the document MS is fed by a predetermined distance from the position detected by the abutting sensor 72. As a result, the document MS is fed in a state where the document MS is pressed against the pull-out roller pair 86 with a predetermined amount of bending. The conveyance of the document MS by the belt 84 is stopped.
When the leading edge of the document MS is detected by the abutting sensor 72, the pickup lift motor 101 is rotated so that the pickup roller 80 is retracted from the upper surface of the document MS, and the document MS is sent only by the conveying force of the paper feed belt 84. As a result, the leading edge of the document MS enters the nip formed by the upper and lower rollers of the pull-out roller pair 86, and leading edge alignment (skew correction) is performed.

As described above, the pull-out roller pair 86 has a skew correction function, and is a roller pair for transporting the document MS corrected in skew after separation to the intermediate roller pair 66. One is driven.
The document MS sent out by the pull-out roller pair 86 passes directly under the document width sensor 73. The document width sensor 73 is a sensor in which a plurality of paper detection sensors such as a reflection type photosensor are arranged in the document width direction (direction orthogonal to the drawing sheet), and based on which paper detection sensor detects the document MS. Thus, the size of the document MS in the width direction is detected. The length of the document MS in the conveyance direction is from the time when the leading edge of the document MS is detected by the abutting sensor 72 to the time when the document MS is not detected by the abutting sensor 72 (the trailing edge of the document MS passes). Detect from motor pulse based on timing.

The document MS conveyed by the drive of the pull-out roller pair 86 and the intermediate roller pair 66 enters the turn part D conveyed by the intermediate roller pair 66 and the reading entrance roller pair 90.
The intermediate roller pair 66 is configured such that the drive is transmitted from both the pull-out motor 113 which is a drive source of the pull-out roller pair 86 and the reading inlet motor 114 which is a driving source of the reading inlet roller pair 90. A mechanism is provided in which the rotational speed is determined by driving the motor on the side of the two motors whose rotational speed is faster.
In the image reading unit 50, when the document MS is conveyed from the registration unit C to the turn unit D by the rotational drive of the pull-out roller pair 86 and the intermediate roller pair 66, the conveyance speed at the registration unit C is set to the first reading conveyance unit. The speed is set to be higher than the transport speed at E, and the processing time for feeding the document MS to the first reading transport section E is shortened. At this time, the intermediate roller pair 66 rotates using the pull-out motor 113 as a drive source.

  When the leading edge of the document MS is detected by the reading entrance sensor 67, the transportation speed of the document MS is set to the first scanning transportation before the leading edge of the document MS enters the nip formed by the upper and lower rollers of the pair of scanning entrance rollers 90. In order to make it the same speed as the conveyance speed in the part E, the pull-out motor 113 starts decelerating. At the same time, the reading inlet motor 114 and the reading motor 103 are driven forward. When the reading inlet motor 114 is driven to rotate forward, the reading inlet roller pair 90 is rotationally driven in the conveying direction, and when the reading motor 103 is driven to rotate forward, the reading outlet roller pair 92 and the second reading outlet roller pair 93 are moved in the conveying direction. To drive each.

When the registration sensor 65 detects the leading edge of the document MS from the turn portion D toward the first reading conveyance portion E, the controller 100 decelerates the drive of each motor over a predetermined time, thereby increasing the conveyance speed of the document MS. Decelerate over a predetermined transport distance. Then, the controller 100 controls the original MS to be temporarily stopped before the first reading position 400 by the first fixed reading unit 151 and transmits a registration stop signal to the main body control unit 111 via the I / F 107. .
Subsequently, when the controller 100 receives a reading start signal from the main body control unit 111, the transport speed of the document MS is set to a predetermined transport speed until the leading edge of the document MS whose registration is stopped reaches the first reading position 400. The driving of the reading inlet motor 114 and the reading motor 103 is controlled so as to rise up to As a result, the document MS is conveyed toward the first reading position 400 while the conveyance speed is increased. Then, at the timing when the leading edge of the document MS calculated based on the pulse count of the reading entrance motor 114 reaches the first reading position 400, the sub-scan of the first surface of the document MS from the controller 100 to the main body control unit 111 is performed. A gate signal indicating a direction effective image area is transmitted. This transmission is continued until the trailing edge of the document MS leaves the first reading position 400, and the first surface of the document MS is read by the first fixed reading unit 151.

The document MS that has passed through the first reading / conveying section E passes through the nip of the reading exit roller pair 92, and then the leading edge thereof is detected by the paper discharge sensor 61, and then passes through the second reading / conveying section F. It is conveyed to the paper discharge unit G.
When reading only one side (first side) of the document MS, the second fixed reading unit 95 does not need to read the second side of the document MS. Therefore, when the leading edge of the document is detected by the paper discharge sensor 61, the forward drive of the paper discharge motor 104 is started, and the upper paper discharge roller in the drawing roller pair 94 in the counterclockwise direction in the drawing. Driven by rotation. The timing at which the trailing edge of the document MS exits the nip of the sheet discharge roller pair 94 is calculated based on the pulse count of the sheet discharge motor 104 after the leading edge of the document MS is detected by the sheet discharge sensor 61. Based on this calculation result, the driving speed of the paper discharge motor 104 is reduced at a timing immediately before the trailing edge of the original MS comes out of the nip of the discharge roller pair 94, and the original MS is removed from the original stack base 55. Control is made so that the paper is discharged at such a speed as not to jump out.

  On the other hand, when both sides (first side and second side) of the document MS are read, the timing from when the leading edge of the document MS is detected by the paper discharge sensor 61 until reaching the second fixed reading unit 95 is read. Calculation is performed based on the pulse count of the motor 103. At that timing, the controller 100 transmits a gate signal indicating an effective image area in the sub-scanning direction on the second surface of the document MS to the main body control unit 111. This transmission is continued until the trailing edge of the document MS exits the second reading position by the second fixed reading unit 95, and the second surface of the document MS is read by the second fixed reading unit 95.

  The second fixed reading unit 95 as a reading unit includes a contact image sensor (CIS), and for the purpose of preventing a reading vertical streak caused by a paste-like foreign material adhering to the document MS adhering to the reading surface. The reading surface is coated. Further, a second reading roller as a document supporting means for supporting the document MS from the non-reading surface side (first surface side) is located at a position facing the second fixed reading unit 95 across the conveyance path through which the document MS passes. 96 is arranged. The second reading roller 96 serves as a reference white portion for suppressing shading of the document MS at the second reading position by the second fixed reading unit 95 and acquiring shading data in the second fixed reading unit 95. Is responsible.

  As shown in FIG. 1, the ADF 51 of the present embodiment detects the leading edge of the document MS conveyed at a predetermined position in the document conveying section 54, and sends a leading edge detection signal to the controller 100 which is a sheet material call control means. A tip detection sensor S1 for transmission is provided. Further, the ADF 51 includes a target length sensor S4 for determining whether or not the size of the document MS set on the document placing table 53 is a target size that should increase productivity such as A4 paper.

Here, as a comparative example, a configuration without the tip detection sensor S1 and the target length sensor S4 will be described.
45 to 49 are schematic explanatory diagrams of portions corresponding to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D in the ADF 51 of the comparative example. 45 to 49 show changes in the state of the previous document MS1 and the next document MS2, which are two documents transported continuously, from when the previous document MS1 starts to be transported to when the next document MS2 begins to be transported. ing.
As shown in FIG. 45, when the pickup roller 80 is in contact with the upper surface of the previous document MS1 at the top of the bundle of documents MS, the pickup roller 80 is rotated as indicated by the arrow in the drawing, whereby the previous document. MS1 starts to be conveyed toward the paper feed port 48. As the pickup roller 80 continues to rotate, the previous original MS1 is sent to the separation conveyance unit B including the paper supply belt 84 and the reverse roller 85 as shown in FIG.
When the leading edge of the previous original MS1 is detected by the abutting sensor 72, control for raising the pickup roller 80 is started. As a result, as indicated by an arrow c in FIG. 47, the pickup roller 80 moves up, and at the timing when the leading edge of the previous document MS1 passes through the pull-out roller pair 86, the pickup roller 80 applies a conveying force to the previous document MS1. It will be in a state that does not.

Thereafter, conveyance by the paper feed belt 84, the pull-out roller pair 86, and the intermediate roller pair 66 is performed. When the conveyance of the previous original MS1 further proceeds from the state shown in FIG. 47, as shown in FIG. The end passes the detection position of the separation sensor S3. Here, in order to prepare for feeding the next original MS2, when the separation sensor S3 detects the trailing edge of the previous original MS1, control for lowering the pickup roller 80 is started as indicated by an arrow d in FIG. After the pickup roller 80 is lowered and the pickup roller 80 grips the next original MS2, the pickup roller 80 starts rotating as shown in FIG. 49, and the next original MS2 is fed.
Here, by setting the conveyance speed by the pickup roller 80, the paper feed belt 84, the pull-out roller pair 86, and the intermediate roller pair 66 to be higher than the conveyance speed in the first reading conveyance section E, the next original MS2 The leading edge can be brought close to the trailing edge of the front document MS1, and the space between the sheets can be reduced.

However, as the conveyance speed of the original MS that can read the original image is increased, when the original MS is conveyed at the reading position at a high speed, the rear end of the front original MS1 is separated and separated as in the comparative example. When the pick-up roller 80 starts to descend using the passage of as a trigger, the time required for the pick-up roller 80 to descend is a time lag. In particular, when the number of sheets that can be read per minute exceeds 100 sheets, the required inter-sheet time becomes very short, and when the trailing edge of the front document MS1 is detected and the pickup roller 80 is lowered. There is a problem that the feeding timing of the next original MS2 cannot keep up with the required paper interval.
In the method of starting the control for feeding the next original MS2 triggered by the fact that the rear end of the previous original MS1 has passed through the separation conveyance unit B as in the comparative example, first, the rear end of the previous original MS1 is detected. The time until the pickup roller 80 that has started to descend from the upper surface of the next original MS2 comes down is a time lag. Further, the time from when the pickup roller 80 comes into contact with the upper surface of the next original MS2 until the pickup conveyance motor 115 starts to be driven until the next original MS2 starts to be conveyed also becomes a time lag. Due to such a time lag, an extra sheet space as indicated by L in FIG. 49 occurs. If there is such an excess paper space, the paper space is not shortened, so that the next original cannot be conveyed promptly and it is difficult to improve productivity.

  Specifically, as the time from the start of driving the pickup transport motor 115 to the start of transporting the next original MS2, it takes time for the pickup transport motor 115 to rise. For example, the rise time of the stepping motor is about 0.05 to 0.1 seconds. Here, when the number of sheets that can be read per minute exceeds 100, the time required between the sheets is 0.1 to 0.2 seconds. When the control for conveying the document is started, the time required for starting up the motor greatly affects the productivity. The rise time of the motor that affects the productivity in this way also occurs in the period from when the pickup lift motor 101 starts to be driven until the pickup roller 80 starts to descend.

Further, as a configuration for separating the documents MS one by one from the bundle of documents MS on the document placing table 53, it is common to employ a frictional separation method as in the separation conveyance unit B. In this case, like the automatic document feeder described in Patent Document 2, a document calling member such as a pickup roller 80 for calling the document MS to the separation unit is kept pressed on the upper surface of the document. It is conceivable to reduce the time lag due to the contact / separation operation of the original calling member. However, if the previous document is conveyed while the document calling member is in contact with the upper surface of the document and is pressed, the previous document and the next document are rubbed, which may cause document contamination. Furthermore, in a state where the original calling member is in contact with the upper surface of the original and is pressed, there is a problem that the close contact between the previous original and the next original is increased, and double feeding is likely to occur.
On the other hand, since the contamination of the original can be reduced by separating the original calling member or releasing the pressure, it is desirable that the original calling member be in contact with and separated from the original.
Further, even though the problem of the time lag required for the movement of the original calling member can be solved, the problem of the time lag required for starting up the driving source of the original calling member remains unresolved.

[Example 1]
Next, a first example (hereinafter referred to as Example 1) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 8 is a schematic explanatory diagram up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the ADF 51 according to the first embodiment.
The ADF 51 according to the first embodiment illustrated in FIG. 8 is a target for detecting the leading edge detection sensor S1 that detects the leading edge of the document MS in the ADF 51 according to the comparative example described above and the size of the document MS that is set on the document placement table 53. It is the structure which added object length sensor S4 for discriminating whether it is a size.
The ADF 51 according to the first exemplary embodiment includes a medium size length sensor 57 and two large size length sensors 58 (58a and 58b) as document length sensors, similarly to the ADF 51 according to the comparative example described above. These three document length sensors (57, 58a, 58b) detect the provisional size of the document MS stacked on the document mounting table 53, and the controller 100 receives the detection result signal so that the document mounting table 53 is received. The provisional size information of the document MS loaded on is acquired.

A document width sensor 73 that detects the size of the document MS in the width direction based on information on the provisional size based on the detection results of the three document length sensors or in addition to the detection results of the three document length sensors. It is also possible to determine whether or not the size of the document MS is a target size that should increase productivity based on the provisional size information based on the detection result. In the first embodiment, by adding the target length sensor S4 in addition to the above three document length sensors, documents having different sizes and the same width size as a predetermined size paper, but only different lengths. It is possible to respond when the MS is placed.
For example, when the size of the object whose productivity is to be increased is A4 side, the length in the transport direction is 210 [mm]. Here, when the distance between the position detected by the target length sensor S4 and the document leading edge setting position (indicated by the arrow J in the figure) is L1 [mm], L1 is 210 [mm] + α [mm]. By setting so as to be, it becomes possible to make a fine document size determination according to the document size.
The setting of α is determined in consideration of an error range (for example, ± 2 [mm]) that the image reading unit 50 can read as a standard size, a layout shift amount due to other factors, and the like. Further, it may be set so that it can be used together with A4 horizontal (210 [mm]) and other sizes in the vicinity (for example, letter size (LT) horizontal: 216 [mm]). When used in combination with the letter size side, α is 8 [mm] or more.

FIG. 9 is an example in which the target length sensor S4 for determining whether or not the size is a target of which productivity should be increased is composed of two sensors, an upstream length sensor S4a and a downstream length sensor S4b. . In this example, the upstream length sensor S4a is arranged at a position where the distance from the document leading edge setting position J is L1a, and the downstream length sensor S4b is a position where the distance from the document leading edge setting position J is L1b. Is arranged. Here, when the size of the object whose productivity should be increased is L0,
L1b <L0 <L1a
The upstream length sensor S4a and the downstream length sensor S4b are arranged so as to satisfy the relationship. With the configuration shown in FIG. 9, when the document MS is detected by the downstream length sensor S4b and the document MS is not detected by the upstream length sensor S4a, the document MS placed on the document table 53 is productive. Can be determined to be the size of the target to be increased.

Next, the operation of the ADF 51 according to the first embodiment shown in FIG. 8 will be described. 10 to 15 are explanatory diagrams showing a state in which two originals MS (previous original MS1 and next original MS2) which are successively conveyed by the ADF 51 of FIG. 8 are conveyed, and FIG. 6 is a timing chart showing the driving timing of each motor in the ADF 51.
FIG. 16 shows the timing of changes in the lifted state of the pickup roller 80, the drive state of the pickup transport motor 115, the drive state of the paper feed motor 102, and the drive state of the pull-out motor 113.

  The pickup roller 80 is raised or lowered by driving the pickup raising / lowering motor 101 so that the pickup roller 80 is in contact with the document MS placed on the document table 53 from a separated state, or is in contact with the pickup roller 80. It changes from a state to a separated state. As the drive control of the pickup lifting / lowering motor 101, a configuration in which the rotation direction of the pickup lifting / lowering motor 101 is controlled to be separated and contacted only by normal rotation, and a configuration in which separation and contact are controlled by forward rotation and reverse rotation. Either configuration can be used.

The pick-up conveyance motor 115 and the paper feed motor 102 require a rise time to reach a predetermined rotation speed from the stopped state, and further, a fall time to reach a stop state from the predetermined rotation speed. Cost. In FIG. 16, regarding the driving states of these motors, the stopped state is “OFF”, and the driving state at a predetermined rotational speed is “ON”.
Similarly, the pull-out motor 113 requires a rise time and a fall time. However, the pull-out motor 113 according to the first embodiment rotates at a rotational speed corresponding to a “pull-out linear speed” described later and a “read linear speed”. The predetermined rotation speed changes depending on the timing, in two types of rotation speeds. For this reason, in FIG. 16, regarding the driving state of the pull-out motor 113, the driving state at a predetermined rotational speed corresponding to the pull-out linear speed is “pull-out linear speed”, and the driving is performed at a predetermined rotational speed corresponding to the reading linear speed. The state in which the reading is performed is “reading line speed”, and the stopped state is “OFF”.

The timing (i) in the timing chart of FIG. 16 is the timing at which the job is started. As shown in FIG. 16, before the job is started, the pickup roller 80 is in a “separated” state, and the pickup conveyance motor 115, the paper feed motor 102, and the pull-out motor 113 are in an “OFF” state.
When the job is started, the pickup raising / lowering motor 101 is driven to bring the pickup roller 80 in the “separated” state into “contact”, and the pickup roller 80 is moved as shown in timing (ii) in FIG. When it is in the “contact” state, the pickup lifting / lowering motor 101 stops. At timing (ii), driving of the pickup transport motor 115 and the paper feed motor 102 is started.

  FIG. 10 shows the state at timing (1) in FIG. In the state shown in FIG. 10, the pickup roller 80 is in contact with the upper surface of the previous original MS1. It should be noted that the start-up time elapses after the pickup conveyance motor 115 and the paper feed motor 102 are started to be driven at the timing (ii), so that the front document MS1 is started to be conveyed by the pickup roller 80. In the first embodiment, the pickup conveying motor 115 applies a conveying force to the document MS from the pickup roller 80 after the pickup conveying motor 115 reaches a predetermined rotation number. However, in the actual machine, the pickup conveying motor 115 has a predetermined rotation number. Even before reaching, the pickup roller 80 starts to rotate, so that the application of the conveyance force from the pickup roller 80 to the document MS is started.

  FIG. 11 shows the state at timing (2) in FIG. In the state shown in FIG. 11, the leading edge of the previous original MS 1 conveyed by the rotation of the pickup roller 80 has reached the entrance of the separation nip portion constituted by the paper feed belt 84 and the reverse roller 85.

  FIG. 12 shows the state at timing (3) in FIG. When the front document MS1 is transported from the state of FIG. 11 and the leading end thereof is detected by the abutment sensor 72 as shown in FIG. 12, the pickup raising / lowering motor 101 is driven and the pickup roller 80 in the “contact” state is moved. As shown by the arrow c in FIG. 12, the movement starts in the direction of “separating” from the upper surface of the previous original MS1. Further, when the leading edge of the previous document MS1 is detected by the abutting sensor 72 at the timing (3), the driving of the pickup conveyance motor 115 and the paper feed motor 102 starts to stop, and the timing after the fall time has elapsed ( In iii), the pickup transport motor 115 and the paper feed motor 102 are stopped. Note that after the pickup roller 80 is separated from the upper surface of the previous document MS1, the previous document MS1 is conveyed by the surface movement of the sheet feeding belt 84 that is rotated by the driving of the sheet feeding motor 102 during the fall time.

  The previous original MS1 whose leading edge is detected by the abutting sensor 72 further advances and abuts against the pull-out roller pair 86 whose rotation is stopped. Here, the paper feed motor 102 is driven and stopped for a predetermined time (the fall time of the paper feed motor 102 in the first embodiment) from the detection of the tip by the abutting sensor 72 (timing (iii) in FIG. 16). Accordingly, the leading edge of the previous document MS1 is fed a predetermined amount from the position detected by the abutting sensor 72. As a result, the leading edge of the preceding document MS1 enters a nip formed by the upper and lower rollers of the pull-out roller pair 86, and the sheet feeding belt 84 is pressed in a state where the preceding document MS1 is pressed against the pull-out roller pair 86 with a predetermined amount of deflection. The conveyance of the previous original MS1 is stopped, and the leading edge of the previous original MS1 is aligned (skew correction).

Thereafter, the pull-out motor 113 starts to be driven at a predetermined pull-out start timing (timing (iv) in FIG. 16), and the front document MS1 is directed to the intermediate roller pair 66 and the first fixed reading unit 151 on the downstream side thereof. Transport. The rotation speed of the pull-out motor 113 at this time is pulled out at a “pull-out linear speed” that is a linear speed higher than the “reading linear speed” that is the linear speed of the original MS when the reading entrance roller pair 90 conveys the original MS. The roller pair 86 is accelerated to a rotating speed. At this time, the drive of the intermediate roller pair 66 is transmitted from the pull-out motor 113 and rotates so as to have the same linear velocity (pull-out linear velocity) as the pull-out roller pair 86.
Further, the pull-out motor 113 starts to be driven at timing (iv), but the paper feed motor 102 is in the “OFF” state. A one-way clutch is connected to the rotation shaft of the drive roller 82 that transmits the drive from the paper feed motor 102 to the paper feed belt 84, and the document MS held between the paper feed belt 84 and the reverse roller 85 is pulled out by the pull-out roller pair 86. When the paper feed motor 102 is in the “OFF” state, the paper feed belt 84 and the reverse roller 85 are rotated along with the movement of the document MS.

  When the previous document MS1 is transported from the state of timing (iv) in FIG. 16 and the leading edge thereof is detected by the reading entrance sensor 67, the rotation speed of the pull-out motor 113 corresponds to the “pull-out linear speed”. To start deceleration so as to reach a rotational speed corresponding to the “reading linear velocity” (timing (v) in FIG. 16). The pull-out motor 113 whose rotational speed has reached the rotational speed corresponding to the “reading linear speed” continues to be driven, and starts to stop when the abutment sensor 72 detects the passage of the previous original MS1 (timing (vi in FIG. 16) )), Stop after the fall time.

  FIG. 13 shows the state at timing (4) in FIG. When the front document MS1 is transported from the state of FIG. 12 and the leading edge thereof is detected by the leading edge detection sensor S1 as shown in FIG. 13, the pickup lifting / lowering motor 101 is driven, and the pickup roller 80 in the “separated” state is illustrated. 13 begins to move in the direction of “contact” with the upper surface of the previous original MS1, as indicated by an arrow d in FIG. 13, and then “contacts” with the upper surface of the next original MS2 as shown in FIG.

FIG. 14 shows a state at timing (5) in FIG. While the previous original MS1 is being conveyed from the state of FIG. 13, the pickup roller 80 is lowered and the pickup roller 80 is in contact with the upper surface of the next original MS2. From this state, the pickup conveyance motor 115 and the paper feed motor 102 are started to be driven. It takes a rise time until the pickup conveyance motor 115 is driven and the pickup roller 80 starts conveying the next original MS2. Immediately, the conveyance of the next original MS2 is not started.
As shown in FIG. 14, in the first embodiment, the pickup roller 80 is lowered, and at the timing when it comes into contact with the upper surface of the bundle of documents MS placed on the document table 53, the pickup roller 80 is located at the rear end of the front document MS1. It passes through the abutting position. In this way, if the pickup roller 80 contacts the upper surface of the bundle of documents MS (the next document MS2) after the rear end of the previous document MS1 passes, the pickup roller 80 contacts with the rotation of the pickup roller 80 fixed. There is no problem. However, when the pickup roller 80 is in contact with the document MS, if the trailing edge of the previous document MS1 does not pass through the contact position of the pickup roller 80, the pickup roller 80 sandwiches the rear end side of the moving front document MS1. Therefore, there is a risk of obstructing the conveyance of the previous original MS1. Such a problem can be prevented by providing a torque limiter (not shown) in the drive transmission portion from the pickup conveyance motor 115 to the pickup roller 80 so that the pickup roller 80 is rotated.

FIG. 15 shows the state at timing (6) in FIG. When the rise time elapses from the state of FIG. 14, the next original MS 2 starts to be conveyed by the rotation of the pickup roller 80. At this time, the rear end of the front document MS1 passes through the separation nip as shown in FIG. If the trailing edge of the previous document MS1 has passed through the separation nip portion, it is possible to prevent the occurrence of double feeding even if the feeding force is started to be applied to the next document MS2. The position of the next original MS2 in the state shown in FIG. 15 is the same as the position of the previous original MS1 in FIG. 10, and the above-described control is repeated from the state shown in FIG. Thus, the document MS can be continuously conveyed.
Here, the time from when the pickup roller 80 is lowered from the trigger for starting the conveyance of the next original MS2 to when the conveyance of the next original MS2 by the pickup roller 80 is started is shown in FIG. 16 as a time lag t1 [s]. And In this case, the detection position by the leading edge detection sensor S1 is shorter than the time lag t1 [s] after the leading edge detection sensor S1 passes the leading edge of the document MS and the trailing edge of the document MS passes the separation nip. Set as follows.
Specifically, the distance of the conveyance path through which the original MS is conveyed from the position passing through the separation nip to the detection position by the leading edge detection sensor S1 is La [mm], the length of the original MS is L0 [mm], and the pull-out roller pair 86. Is set so that the following equation (a) is established when the conveyance speed of the original MS is V [mm / s].
(L0-La) / V <t1 (a)
When La is set longer than L0, the pickup roller 80 starts to descend after the trailing edge of the front document MS1 has passed the separation nip portion, and the trailing edge of the front document MS1 has passed the separation nip portion. Therefore, it is desirable to satisfy La <L0 since the difference from the conventional example in which the pickup roller 80 starts to descend after the separation sensor S3 is detected is difficult to occur.
By satisfying the relationship of (L0−La) / V <t1 and preventing double feeding, by setting La <L0, the paper gap can be narrowed compared to the conventional example, and the productivity is higher than that of the conventional example. Improvements can be made.

  In the first exemplary embodiment, the position of the rear end of the previous document MS1 that can prevent the occurrence of multifeed even when the feeding force is applied to the next document MS2 is the position after passing the separation nip portion. If it can be prevented, the conveyance of the next original MS2 may be started from the state in which the rear end of the previous original MS1 remains in the separation nip portion.

If the size of the document placed on the document placement table 53 is not the target size that should increase productivity (when the document MS is detected in S4), the trailing edge of the front document MS1 is detected by the separation sensor S3. Using the passage of the position as a trigger, the pickup roller 80 is controlled to start descending.
By setting in this way, regardless of the size of the document, the control for starting the calling operation by the pickup roller 80 can be processed by one sensor (S4).
Here, the calling operation is an operation of lowering the pickup roller 80 and then rotating the pickup roller 80 to start conveying the document MS on the document table 53.

As shown in FIG. 16, in the first embodiment, the drive timings of the pickup transport motor 115 and the paper feed motor 102 are the same, and therefore the rotation and stop timings of the pickup roller 80 and the paper feed belt 84 are the same. . Thus, if the rotation and stop timings are the same, the drive source of the pickup roller 80 and the drive source of the paper feed belt 84 may be a single motor.
Furthermore, the drive timings of the pickup transport motor 115 and the paper feed motor 102 may be different. In the first exemplary embodiment, the paper feed motor 102 is in an “OFF” state at the timing when the pull-out motor 113 is driven after the pickup roller 80 is separated, and the document MS conveyed by the rotation of the pull-out roller pair 86 is held. The paper feed belt 84 and the reverse roller 85 are rotated along with the movement of the document MS. On the other hand, it is also possible to control to drive the paper feed motor 102 so that the paper feed belt 84 rotates at the same linear speed as the pull-out roller pair 86 at the timing of driving the pull-out motor 113.

[Modification]
Next, a modified example (hereinafter referred to as “modified example”) of the ADF 51 in the first embodiment will be described.
FIG. 17 is a schematic explanatory view up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the modified ADF 51. The modified ADF 51 has a configuration in which a double feed detection sensor S5, which is a double feed detection means, is added to the ADF 51 of the first embodiment shown in FIG.

The double feed detection sensor S5 included in the modified ADF 51 is disposed opposite to the transmission unit S5-1 that transmits ultrasonic waves and the transmission unit S5-1, and receives the ultrasonic waves transmitted by the transmission unit S5-1. The receiving unit S5-2. In the double feed detection sensor S5, when the document MS passes between the transmission unit S5-1 and the reception unit S5-2, when the document MS passes through a single sheet, it is in a non-multifeed state and a plurality of sheets. The occurrence of double feed can be detected by utilizing the fact that the reception state of the ultrasonic wave at the receiving unit S5-2 differs depending on the double feed state. In the present modification, the transmission unit S5-1 is arranged on the upper side and the reception unit S5-2 is arranged on the lower side, but the arrangement of the transmission unit S5-1 and the reception unit S5-2 is reversed. Good.
The double feed detection sensor S5 is not limited to the ultrasonic detection sensor as in the present modification, and any detection sensor that can detect double feed of the sheet material may be used. For example, a light transmission type detection sensor including a light emitting unit and a light receiving unit can be used. In this light transmission type detection sensor, it is possible to irradiate the sheet material passing through the detection position with light and detect the occurrence of double feeding of the sheet material based on the amount of light transmitted through the sheet material.

In the modified ADF 51, while the detection result of the double feed detection sensor S5 is in the non-double feed state, the same control as in the first embodiment described with reference to FIGS. The document MS is continuously conveyed toward 300.
Next, in the modified ADF 51, when the next original MS2 is drawn into the separation nip before the rear end of the previous original MS1 passes through the separation nip, that is, the detection result of the double feed detection sensor S5 is double feed. The case where it will be in a state is demonstrated.

In FIG. 18, the conveyance timing of the previous document MS1 is the same as that in FIG. 13 of the first embodiment, and the next document MS2 is drawn into the separation nip portion before the rear end of the previous document MS1 passes through the separation nip portion. It is explanatory drawing which shows.
The state shown in FIG. 18 is the state of timing (4) in FIG. 16 in which the conveyance timing of the previous document MS1 is the same as that in FIG. 13 of the first embodiment. At this time, the paper feed motor is stopped, and the paper feed belt 84 and the reverse roller 85 are rotated along with the movement of the document MS. Therefore, even if the next original MS2 is pulled into the separation nip portion at the timing shown in FIG. 18, the moving force in the direction opposite to the feeding direction by the reverse roller 85 is not applied to the next original MS2. The next original MS2 in the state shown in FIG. 18 is separated from the previous original MS1 by the frictional force with the reverse roller 85 or the rotational resistance of the reverse roller 85 and stopped at that position, or separated from the previous original MS1. Instead, it passes through the separation nip portion together with the previous document MS1.
When the next original MS2 passes through the separation nip portion together with the previous original MS1, it is double-fed to the turn portion D and two reading portions downstream thereof, and as a result, there is a possibility that the read image is adversely affected. Even if the next original MS2 is separated from the previous original MS1 and stopped in the middle of the separation nip portion, the next original document MS1 overlaps with the leading edge of the next original MS2 at the exit of the separation nip portion. When the application of the conveyance force to the MS 2 is started, there is a possibility that the read image is adversely affected due to the double feed.

In the ADF 51 of this modification, as shown in FIG. 18, the next document MS2 is drawn into the separation nip portion before the trailing edge of the previous document MS1 passes through the separation nip portion. When the feeding state is detected, control different from that in the timing chart of FIG. 16 is performed.
When the double feed state is detected, when the leading edge of the previous document MS1 is detected by the leading edge detection sensor S1 as shown in FIG. 18, the pickup lifting / lowering motor 101 is driven, and the pickup roller 80 in the “separated” state is illustrated. As shown by an arrow d in FIG. 18, the movement starts in the direction of “contact” with the upper surface of the previous original MS1, and thereafter, the state “contacts” with the upper surface of the next original MS2 as shown in FIG.

FIG. 19 shows the same timing as that of FIG. 14 of the first embodiment for conveying the previous document MS1 after the next document MS2 is drawn into the separation nip before the trailing edge of the previous document MS1 passes through the separation nip. It is explanatory drawing which shows the state of.
While the previous original MS1 is being conveyed from the state of FIG. 18, the pickup roller 80 is lowered, and the pickup roller 80 is in contact with the upper surface of the next original MS2. In the timing chart of FIG. 16, driving of the pickup conveyance motor 115 and the paper feed motor 102 is started from this state. However, in the modified ADF 51, when the double feed detection sensor S5 detects the double feed state, FIG. Even if it becomes a state, the drive of these motors is not started.
Further, when the previous document MS1 is conveyed from the state of FIG. 19 and the trailing end thereof passes the detection position of the double feed detection sensor S5, the detection signal of the double feed detection sensor S5 changes from the double feed state to the non-double feed state. At this time as well, there is a possibility that the rear end of the previous original MS1 and the front end of the next original MS2 are overlapped with each other.

FIG. 20 is an explanatory diagram showing a state after the front document MS1 is further conveyed from the state of FIG. 19 and the rear end of the front document MS1 has passed the detection position of the separation sensor S3.
In the modified ADF 51, after the detection signal of the double feed detection sensor S5 has changed from the double feed state to the non-double feed state, as shown in FIG. 20, the fact that the rear end of the front document MS1 has passed through the separation nip portion. After the detection by the separation sensor S3, driving of the pickup transport motor 115 and the paper feed motor 102 is started. Thereafter, after the start-up time of the motor has elapsed, the conveyance of the next original MS2 is started.
As described above, in the modification, when the double feed detection sensor S5 detects the double feed state, the rear end of the previous original MS1 is detected by the separation sensor S3, and the rear end of the previous original MS1 and the front end of the next original MS2 are detected. After the separation is confirmed, the next original MS2 is controlled to be conveyed. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.
Thereafter, while the detection result of the double feed detection sensor S5 is in the non-double feed state, the same control as in the first embodiment described with reference to FIGS. The original MS is continuously conveyed with the space between the sheets narrowed.

  In the modified ADF 51, while the detection result of the double feed detection sensor S5 is in the non-double feed state, the same control as in the first embodiment described with reference to FIGS. When the detection result is in a double feed state, the document MS can be continuously and stably conveyed toward the fixed image reading unit 300 by performing the control described with reference to FIGS.

Note that after the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the next original MS2 cannot be separated from the previous original MS1, and the separation nip portion is moved together with the previous original MS1 without stopping at the separation nip portion. If the leading edge of the next document MS2 passes through the detection position of the separation sensor S3, the separation sensor S3 cannot detect the trailing edge of the preceding document MS1, and the trailing edge of the next document MS2 becomes the trailing edge of the preceding document MS1. There is a risk of false detection. In this case, the next original MS2 is fed to the turn part D and two reading parts downstream thereof together with the previous original MS1, and as a result, the read image may be adversely affected. Further, when the next original MS2 passes through the separation nip portion together with the previous original MS1 without stopping at the separation nip portion, and the leading edge of the next original MS2 passes through the detection position of the separation sensor S3 and is separated and stopped from the previous original MS1. The next original MS2 continues to exist at the detection position of the separation sensor S3, and a signal that triggers the start of driving of the pickup transport motor 115 and the paper feed motor 102, which is the detection of the trailing edge of the original MS by the separation sensor S3. There is a risk that it will never be obtained.
In order to prevent these problems, in the modified ADF 51, when the detection result of the double feed detection sensor S5 is in a double feed state, a predetermined time after the leading edge detection sensor S1 detects the leading edge of the previous document MS1. If the separation sensor S3 does not detect the trailing edge of the front document MS1 even after the elapse of time, the control of stopping the driving of the ADF 51 is performed on the assumption that the document MS needs to be removed or a double feed requiring confirmation of the read image has occurred. You may go.

  In the ADF 51 of the modified example, even when the detection result of the double feed detection sensor S5 is in the double feed state, the pickup lift motor 101 is driven using the detection of the leading edge of the previous document MS1 by the leading edge detection sensor S1 as a trigger. The pickup roller 80 is brought into contact with the upper surface of the next original MS2. The timing at which the pickup lifting / lowering motor 101 is driven when the double feed detection sensor S5 detects double feed is even after the separation sensor S3 detects that the trailing edge of the front document MS1 has passed through the separation nip portion. Good.

[Example 2]
Next, a second example (hereinafter referred to as Example 2) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 21 to FIG. 23 are schematic explanatory views up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the ADF 51 according to the second embodiment. FIG. 24 is a timing chart showing the driving timing of each motor in the ADF 51 of the second embodiment.
The ADF 51 of the second embodiment shown in FIGS. 21 to 23 is different from the ADF 51 of the first embodiment in that a pickup lowering start sensor S2 is provided on the downstream side of the document width sensor 73, but the other configurations are common. Only the differences will be described. Needless to say, the target length sensor S4 may be configured to include the two sensors (upstream length sensor S4a and downstream length sensor S4b) described with reference to FIG.

FIG. 21 shows a state at timing (1) in FIG.
In the ADF 51 of the second embodiment, as shown in FIG. 21, the pickup roller 80 rotates in a state where the pickup roller 80 is in contact with the previous document MS1 on the uppermost part of the document table 53, so that the previous document MS1 is separated. It is conveyed toward the nip part. At this time, the paper feed belt 84 and the reverse roller 85 that form the separation nip portion are also driven, and the previous original MS1 that has entered the separation nip portion passes through the separation nip portion while being subjected to the separation action by the reverse roller 85. Then, when the leading edge of the previous document MS1 is detected by the abutting sensor 72, the drive of the pickup transport motor 115 and the paper feed motor 102 starts to stop as indicated by the timing (i) in FIG. Also, at the timing (i) in FIG. 24, the pickup lifting / lowering motor 101 is driven, and the pickup roller 80 in the “contact” state is “separated” from the upper surface of the previous document MS1 as indicated by an arrow c in FIG. Move in the direction you want.
As shown in FIG. 24, the timing for stopping the driving of the pickup transport motor 115 and the timing for starting the driving of the pickup lifting / lowering motor 101 are simultaneous. In the second exemplary embodiment, since there is a fall time of the pickup transport motor 115, the previous original MS1 is not sandwiched between the pickup rollers 80 where the transmission of driving is stopped. However, depending on the configuration, the previous original MS1 is temporarily stored. In some cases, the state is sandwiched between the pickup rollers 80 in which the drive transmission is stopped. In the ADF 51 of the second embodiment, a torque limiter (not shown) is provided in a drive transmission portion from the pickup conveyance motor 115 to the pickup roller 80. Even if the pickup transport motor 115 stops driving by this torque limiter, when the document MS abutting on the pickup roller 80 is transported by the paper feed belt 84, the pickup roller 80 is rotated along with the movement of the upper surface of the document MS. It is configured.
The trigger for raising the pickup roller 80 may be a trigger after the leading edge of the previous document MS1 has passed through the separation nip portion, and as a sensor for detecting that the previous document MS1 has passed through the separation nip portion, the trigger is used. The contact sensor 72 or the separation sensor S3 may be used.

The previous document MS1 whose leading edge is detected by the abutting sensor 72 further advances by the surface movement of the sheet feeding belt 84, and abuts against the pull-out roller pair 86 whose rotation is stopped. Here, the paper feed motor 102 is driven and stopped for a predetermined time (the fall time of the paper feed motor 102 in the second embodiment) from the detection of the tip by the abutting sensor 72 (timing (ii) in FIG. 24). Accordingly, the leading edge of the previous document MS1 is fed a predetermined distance from the position detected by the abutting sensor 72. As a result, the leading edge of the preceding document MS1 enters the nip formed by the upper and lower rollers of the pull-out roller pair 86, and the sheet feeding belt 84 is pressed in a state where the preceding document MS1 is pressed against the pull-out roller pair 86 with a predetermined amount of deflection. The conveyance of the previous original MS1 is stopped, and the leading edge of the previous original MS1 is aligned (skew correction).
Thereafter, the pull-out motor 113 starts to be driven at a predetermined pull-out start timing (timing (2) in FIG. 24), so that the front document MS1 is placed on the intermediate roller pair 66 and its downstream side as shown in FIG. The conveyance starts toward the first fixed reading unit 151.

  When driving of the pull-out motor 113 is started, the leading edge of the previous original MS1 passes through the nip portion of the pull-out roller pair 86 as shown in FIG. When the leading edge of the previous document MS1 is detected by the pickup lowering start sensor S2, the pickup raising / lowering motor 101 is driven (timing (iii) in FIG. 24). As a result, the pickup roller 80 in the “separated” state starts to descend so as to be in “contact” with the upper surface of the bundle of documents MS on the document table 53 as indicated by an arrow d in FIG. In the ADF 51 of the second embodiment, the pickup roller 80 is detected before the leading edge of the document MS whose leading edge is detected by the pickup lowering start sensor S2 reaches the detection position of the leading edge detection sensor S1 (timing (iv) in FIG. 24). The position of the pickup lowering start sensor S2 is set so that the lowering operation is completed (timing (3) in FIG. 24).

When the lowering operation of the pickup roller 80 is completed, the drive of the pickup raising / lowering motor 101 is stopped, and the state shown in FIG. 23 is reached (the position of the pickup roller 80 is a solid line in the drawing). At this time, the leading edge of the previous document MS1 does not reach the detection position of the leading edge detection sensor S1, and further, the leading edge of the previous document MS1 passes through the detection position of the leading edge detection sensor S1 by being conveyed. When the leading edge of the previous document MS1 is detected by the leading edge detection sensor S1, driving of the pickup conveyance motor 115 and the paper feeding motor 102 is started as a calling operation (timing (iv) in FIG. 24), and after the rise time has elapsed. Then, the conveyance of the next original MS2 by the pickup roller 80 is started (timing (1) ′ in FIG. 24).
Thereafter, by repeating the above-described control, the document MS can be continuously conveyed toward the fixed image reading unit 300.
At the timing when the lowering operation of the pickup roller 80 shown in FIG. 23 is completed, the drive of the pickup conveyance motor 115 is not started as shown by the timing (3) in FIG. For this reason, the pickup roller 80 abuts against the rear end side of the front document MS1 as shown in FIG. 23 without being driven to rotate, but the pickup roller 80 can be rotated as described above. It can be prevented that the pickup roller 80 sandwiches the rear end side of the moving front document MS1 and obstructs the transport of the previous document MS1.

As in the second embodiment, when the pickup roller 80 starts to descend before the leading edge of the previous document MS1 is detected by the leading edge detection sensor S1, the time ta [s] required for the pickup roller 80 to descend is The time lag t1 [s] from the trigger for starting the conveyance of the original MS2 to the start of the conveyance of the next original MS2 can be prevented. As a result, the time ta [s] required for the pickup roller 80 to descend can be prevented from extending the interval between sheets, and the productivity can be prevented from decreasing due to the descending operation.
In the second embodiment, when the size of the document placed on the document placement table 53 is not the target size that should increase the productivity (when the document MS is detected by the target length sensor S4), after the previous document MS1. Control is performed so that driving of the pickup transport motor 115 as a calling operation is started by using, as a trigger, that the end has passed the detection position of the separation sensor S3.

FIG. 25 is an explanatory diagram of a configuration in which a double feed detection sensor S5 similar to the ADF 51 of the above modification is arranged in the ADF 51 of the second embodiment that includes the pickup lowering start sensor S2 on the downstream side of the document width sensor 73.
In the configuration shown in FIG. 25, as in the above modification, when the double feed detection sensor S5 detects the double feed state, the separation sensor S3 detects that the trailing edge of the front document MS1 has passed the separation nip portion. Later, driving of the pickup conveyance motor 115 and the paper feed motor 102 is started. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.
In the configuration shown in FIG. 25, the trigger for starting the driving of the pickup raising / lowering motor 101 to lower the pickup roller 80 may be detection of the leading edge of the previous document MS1 by the pickup lowering start sensor S2, or the previous document by the separation sensor S3. The rear end detection of MS1 may be used.

Here, FIG. 26 shows a flowchart of control for determining a trigger for a call operation having a configuration in which the call operation is performed immediately after detection by the tip detection sensor S1, like the ADF 51 of the first and second embodiments.
As shown in the flowchart of FIG. 26, the controller 100 provided in the ADF 51 of the first and second embodiments first determines whether or not the document MS is detected by the target length sensor S4. That is, it is determined whether or not the length of the document MS on the document table 53 is longer than L1.
If it is determined that the length of the document MS on the document table 53 is longer than L1 (“Y” at the branch in FIG. 26), the call is triggered by the detection of the trailing edge of the document MS by the separation sensor S3. Control to start operation.
On the other hand, if it is determined that the length of the document MS on the document table 53 is shorter than L1 ("N" at the branch in FIG. 26), the calling operation is triggered by the leading edge detection of the document MS by the leading edge detection sensor S1. Control to start.

Like the modified example or the ADF 51 having the configuration shown in FIG. 25, the next document MS2 is started to be transported with the double feed detection sensor S5 and in the non-double feed state, the calling operation is performed immediately after detection by the leading edge detection sensor S1. FIG. 27 shows a flowchart of control for determining the trigger to be performed.
As shown in the flowchart of FIG. 20, the controller 100 provided in the modified example or the ADF 51 having the configuration shown in FIG. 25 first determines the next paper feed timing using the leading edge detection of the document MS by the leading edge detection sensor S1 as a trigger. . It is determined whether the double feed detection sensor S5 detects double feed and whether the target length sensor S4 senses the document MS. That is, it is determined whether or not the leading edge of the next original MS2 overlaps with the previous original MS1 and does not enter the vicinity of the separation nip portion, and whether the length of the original MS on the original placement table 53 is longer than L1. .
Here, when it is determined that the leading edge of the next original MS2 is double-fed (“Y” at the second branch in FIG. 27), or the length of the original MS on the original placement table 53 is longer than L1. When it is determined that the document is long (“Y” at the third branch in FIG. 27), control is performed so that conveyance of the next document MS2 is started with the detection of the trailing edge of the previous document MS1 by the separation sensor S3 as a trigger.
On the other hand, when it is determined that the next document MS2 is not double-fed and the length of the document MS on the document table 53 is shorter than L1 (in the second branch and the third branch in FIG. 27). Both “N”) controls to start the calling operation triggered by the leading edge detection of the document MS by the leading edge detection sensor S1.

Example 3
Next, a third example (hereinafter referred to as Example 3) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 28 and FIG. 29 are schematic explanatory views up to the middle of the document setting portion A, the separation conveyance portion B, the registration portion C, and the turn portion D of the ADF 51 of the third embodiment.
The ADF 51 of the third embodiment combines the function as a trigger for the calling operation of the front end detection sensor S1 of the first embodiment and the function of the pickup lowering start sensor S2 of the second embodiment by a front end detection sensor S1 as one detection means. It is the structure to do.
In the ADF 51 of the third embodiment, the tip detection sensor S1 is arranged at a position where the pickup lowering start sensor S2 is provided in the ADF 51 of the second embodiment. Since the drive timing of each motor of the ADF 51 of the third embodiment is the same as that of the ADF 51 of the second embodiment, the control timing will be described with reference to the timing chart of FIG.

FIG. 28 shows the state at timing (3) in FIG. 24, and FIG. 29 shows the state at timing (1) ′ in FIG. The ADF according to the third embodiment starts the conveyance of the previous document MS1 indicated by the timing (1) in FIG. 24 and then starts the pickup lowering start sensor S2 indicated by the timing (iii) in FIG. The same control is performed until the leading edge of the previous document MS1 is detected.
In the second embodiment, when the pickup lowering start sensor S2 detects the leading edge of the previous document MS1, the pickup roller 80 is lowered, and based on the detection result of the leading edge detection sensor S1 disposed on the downstream side of the pickup lowering start sensor S2. The call operation is started.
On the other hand, in the third embodiment, when the leading edge detection sensor S1 detects the leading edge of the previous document MS1, the pickup roller 80 is lowered, and the controller 100 starts measuring time by counting pulses or the like. When the time elapses, the calling operation is executed, and after the time lag t1 [s] has elapsed, the conveyance of the next original MS2 is started as shown in FIG. The predetermined time here is the time required for the document MS to be conveyed from the detection position of the leading edge detection sensor S1 of the third embodiment to the position corresponding to the detection position of the leading edge detection sensor S1 of the second embodiment. Tb [s] in 24. Information on the predetermined time tb [s] is stored in a storage unit (not shown) of the controller 100.

In the third embodiment, when the leading edge detection sensor S1 detects the leading edge of the previous original MS1, the lowering operation of the pickup roller 80 and the measurement of the time until a predetermined time are performed in parallel. When the leading edge of the document MS1 is detected, only the time until a predetermined time may be measured first. In this case, after a predetermined time elapses from the detection of the tip of the tip detection sensor S1, the lowering operation and the rotation driving operation of the pickup roller 80 are executed as the calling operation. In this case, the time until the next original MS2 starts to be conveyed after a predetermined time elapses is longer than the configuration of the third embodiment by the time required for the lowering operation of the pickup roller 80, and accordingly, the leading edge of the leading edge detection sensor S1. A predetermined time from the detection to the start of the call operation is set short.
As described above, if the control is performed to start the calling operation after a predetermined time has elapsed since the front end detection of the front end detection sensor S1, the distance from the separation nip portion to the detection position of the front end detection sensor S1 is set by a predetermined time. Can be set freely to some extent, and there is an advantage that the degree of freedom of the installation position of the tip detection sensor S1 is increased.

Here, FIG. 30 shows a control flowchart for determining a trigger for a call operation in which a call operation is performed after a predetermined time has elapsed after detection by the tip detection sensor S1 as in the ADF 51 of the third embodiment.
As shown in the flowchart of FIG. 30, the controller 100 provided in the ADF 51 of the third embodiment first determines whether or not the document MS is detected by the target length sensor S4. That is, it is determined whether or not the length of the document MS on the document table 53 is longer than L1.
If it is determined that the length of the document MS on the document table 53 is longer than L1 ("Y" at the branch in FIG. 30), the call is triggered by the detection of the trailing edge of the document MS by the separation sensor S3. Control to start operation.
On the other hand, when it is determined that the length of the document MS on the document table 53 is shorter than L1 ("N" at the branch in FIG. 30), the detection of the leading edge of the document MS by the leading edge detection sensor S1 is used as a trigger. Control is made so that the call operation is started after the elapse of time.

FIG. 31 shows a similar function to that of the ADF 51 of the above-described modification example in the ADF 51 of the third embodiment in which the function as the trigger for the calling operation and the function of the pickup lowering start sensor are combined by the tip detection sensor S1 as one detection means. It is explanatory drawing of the structure which has arrange | positioned sending detection sensor S5.
In the configuration shown in FIG. 31 as well, as in the above modification, when the double feed detection sensor S5 detects the double feed state, the separation sensor S3 detects that the trailing edge of the front document MS1 has passed through the separation nip portion. Later, driving of the pickup transport motor 115 and the paper feed motor 102 is started. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.
In the configuration shown in FIG. 31, the trigger for starting the driving of the pickup lifting / lowering motor 101 for lowering the pickup roller 80 may be the leading edge detection of the leading document MS1 by the leading edge detection sensor S1, or the leading document MS1 by the separation sensor S3. The rear end detection may be used.

As in the ADF 51 having the configuration shown in FIG. 31, a trigger for a call operation having a structure in which a multi-feed detection sensor S5 is provided and a call operation is performed after a predetermined time has elapsed after detection by the tip detection sensor S1 in the non-multi-feed state. FIG. 32 shows a flowchart of control to be determined.
As shown in the flowchart of FIG. 32, the controller 100 provided in the ADF 51 having the configuration shown in FIG. 31 first determines the next paper feed timing using the leading edge detection of the document MS by the leading edge detection sensor S1 as a trigger. It is determined whether the double feed detection sensor S5 detects double feed and whether the target length sensor S4 senses the document MS. That is, it is determined whether or not the leading edge of the next original MS2 overlaps with the previous original MS1 and does not enter the vicinity of the separation nip portion, and whether the length of the original MS on the original placement table 53 is longer than L1. .
Here, when it is determined that the leading edge of the next original MS2 is double-fed (“Y” at the second branch in FIG. 32), or the length of the original MS on the original placement table 53 is longer than L1. If it is determined that the document is long (“Y” at the third branch in FIG. 32), control is performed so that conveyance of the next document MS2 is started by using the trailing edge detection of the previous document MS1 by the separation sensor S3 as a trigger.
On the other hand, when it is determined that the next original MS2 is not double-fed and the length of the original MS on the original placement table 53 is shorter than L1, the second branch and the third branch in FIG. Both “N”) are controlled so that the calling operation is started after a predetermined time elapses, triggered by detection of the leading edge of the document MS by the leading edge detection sensor S1.

Example 4
Next, a fourth example (hereinafter referred to as Example 4) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 33 is a schematic explanatory diagram up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the ADF 51 according to the fourth embodiment.
In the first to third embodiments, there is one tip detection sensor S1 serving as a trigger for starting the calling operation, but a plurality of tip detection sensors S1 may be provided. As shown in FIG. 33, the ADF 51 of the fourth embodiment includes the two tip detection sensors S1 (first tip detection sensor S1-1 and second tip detection sensor S1-2), as shown in FIG. Different from ADF51. Further, two target length sensors S4 are provided for determining whether or not the size of the document MS is a target size that should increase productivity (first target length sensor S4-1, second target length). The sensor S4-2) also differs from the ADF 51 of the first embodiment.
That is, in the ADF 51 of the fourth embodiment, the same number of tip detection sensors S1-1, 2, 3,... N corresponding to each of a plurality of target length sensors S4-1, 2, 3,. It is the structure provided with.

The ADF 51 according to the fourth embodiment has a configuration in which a plurality of sizes of targets to be improved in productivity can be set. In the example shown in FIG. 33, two types of sizes can be set. For example, when the B5 horizontal size (182 [mm]) and the A4 horizontal size (210 [mm]) are set as the sizes to be increased in productivity, L1-1 = 182 [mm] + α1 [mm], L1 The positions of the two target length sensors S4 (S4-1, S4-2) are set so as to look at −2 = 210 [mm] + α2 [mm].
The arrangement of the plurality of target length sensors S4 is not necessarily the same as the provisional size detection sensor or the like that has been installed for the purpose of classifying the size of a conventional document (in combination with the width size sensor). The position and number are determined by the point of view of improving sex. If possible, it may also be used as a conventional temporary size detection sensor or the like.

FIG. 34 is a flowchart of control for determining a trigger for a call operation of a configuration including a plurality of tip detection sensors S1 and a target length sensor S4 as in the ADF 51 of the fourth embodiment.
As shown in the flowchart of FIG. 34, the controller 100 included in the ADF 51 according to the fourth embodiment first determines whether or not the document MS is sensed by all of the plurality of target length sensors S4. That is, it is determined whether or not the length of the document MS on the document placement table 53 is longer than the maximum length L1−N (L1max).
If it is determined that the length of the document MS on the document table 53 is longer than L1max ("Y" at the branch in FIG. 34), the call is triggered by the detection of the trailing edge of the document MS by the separation sensor S3. Control to start operation.
On the other hand, when it is determined that the length of the document MS on the document placement table 53 is shorter than L1max ("N" at the branch in FIG. 34), which of the plurality of L1-N has the length of the document MS? To determine whether it is true. This determination is made when the original MS is detected by the (N-1) th target length sensor S4- (N-1) and is not detected by the Nth target length sensor S4-N. The length is determined as L1-N.
Then, based on the determination result, the tip detection sensor S1 used for tip detection is determined.

As a specific example, in the case of the fourth embodiment, when both the first target length sensor S4-1 and the second target length sensor S4-2 detect the document MS, the length of the document MS should increase productivity. It is determined that the size is not the target size, and control is performed so that the calling operation is started with the detection of the trailing edge of the document MS by the separation sensor S3 as a trigger.
When the document MS is detected by the first target length sensor S4-1 and the document MS is not detected by the second target length sensor S4-2, the length of the document MS is determined as L1-2, It is determined that tip detection is performed by the two-tip detection sensor S1-2. When neither the first object length sensor S4-1 nor the second object length sensor S4-2 senses the document MS, the length of the document MS is determined as L1-1, and the first leading edge detection sensor. It is determined to perform tip detection in S1-1.

After the leading edge detection sensor S1 used for leading edge detection is determined, the same control as in the first embodiment is performed as the driving timing of each motor, and the document MS is continuously conveyed toward the fixed image reading unit 300. To do.
The timing at which the next document MS2 can be started after the previous document MS1 on the document table 53 starts to be transported varies depending on the length of the document MS, but the length of the document MS as in the fourth embodiment. Accordingly, by determining the leading edge detection sensor S1 serving as a trigger for the calling operation, it is possible to set so that the next original MS2 can be started at a timing corresponding to the length of the original. As a result, a plurality of sizes can be set as targets to increase productivity.

In the fourth embodiment, when it is determined that the length of the document MS on the document placement table 53 is longer than L1max (“Y” in the branch in FIG. 34), the calling operation is triggered by the detection of the rear end of the separation sensor S3. It has started, but is not limited to this. For example, the control may be performed to start the calling operation after a sufficient time has elapsed after the tip detection by the tip detection sensor S1 disposed on the most downstream side of the plurality of tip detection sensors S1.
In the fourth embodiment, a plurality of target length sensors S4 and a tip detection sensor S1 are provided so that a plurality of target sizes that should increase productivity can be set. Instead of arranging a plurality of these sensors (S4 and S1), a linear sensor is arranged in one or both of the target length sensor S4 and the tip detection sensor S1, and the detection position can be displaced to increase productivity. You may comprise so that the size of the target should be set in multiple sizes.

In the ADF 51 of the fourth embodiment, after the tip detection sensor S1 to be used is determined, as in the first embodiment, the pickup roller 80 is lowered as a calling operation that is executed using the tip detection as a trigger. Performs rotation. The calling operation that is performed using the tip detection as a trigger may be configured to perform only the rotation operation of the pickup roller 80 without performing the lowering operation of the pickup roller 80. In the case of this configuration, the pickup roller 80 is in contact with the upper surface of the document MS on the document table 53 even after the pickup roller 80 is stopped driving. It is configured so that it can be rotated with respect to movement.
However, as described above, it is desirable that the pickup roller 80 is configured to come into contact with and separate from the document MS from the viewpoint of preventing document smearing and double feeding.

FIG. 35 is an explanatory diagram of a configuration in which a double feed detection sensor S5 similar to the ADF 51 of the above modification is disposed on the ADF 51 of the fourth embodiment in which a plurality of tip detection sensors S1 and target length sensors S4 are provided.
In the configuration shown in FIG. 35 as well, in the same way as in the above modification, when the double feed detection sensor S5 detects the double feed state, the separation sensor S3 detects that the trailing edge of the front document MS1 has passed the separation nip portion. Later, the pickup conveyance motor 115 and the paper feed motor 102 are started to be driven. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.

Like the ADF 51 having the configuration shown in FIG. 35, the multi-feed detection sensor S5 is provided, and in the non-multi-feed state, the calling operation is performed immediately after detection by the leading edge detection sensor S1-N determined based on the document length. FIG. 36 shows a flowchart of control for determining a trigger for starting the conveyance of the next original MS2.
As shown in the flowchart of FIG. 36, in the ADF 51 having the configuration shown in FIG. 35, when the document MS is detected by all the target length sensors S4, and when the double feed is detected by the double feed detection sensor S5. Controls the start of the conveyance of the next original MS2 triggered by the detection of the trailing edge of the previous original MS1 by the separation sensor S3.
On the other hand, if it is determined that the length of the document MS on the document table 53 corresponds to any one of L1-1 to L1-N and the next document MS2 is not double-fed, the length L1- Control is performed so as to start the calling operation with the leading edge detection of the document MS by the leading edge detection sensor S1-N corresponding to N as a trigger.

Example 5
Next, a fifth example (hereinafter referred to as Example 5) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 37 is a schematic explanatory diagram up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the ADF 51 according to the fifth embodiment.
Similar to the ADF 51 of the fourth embodiment, the ADF 51 of the fifth embodiment includes two tip detection sensors S1 and two target length sensors S4, and further includes two pickup lowering start sensors S2. That is, the ADF 51 of the second embodiment has one sensor (S4, S1, S2), whereas the ADF 51 of the fifth embodiment has a plurality of target length sensors S4-1, 2, 3 ... With the same number of tip detection sensors S1-1, 2, 3,... N and pickup lowering start sensors S2-1, 2, 3,. is there.
The ADF 51 according to the fifth embodiment is configured to be able to set a plurality of sizes of targets whose productivity is to be increased as in the fourth embodiment. In the example shown in FIG. 37, two types of sizes can be set.

FIG. 38 shows a trigger for a call operation (start of driving of the pickup transport motor 115) having a plurality of tip detection sensors S1, pickup lowering start sensors S2, and target length sensors S4 as in the ADF 51 of the fifth embodiment. It is a flowchart of the control which determines.
As shown in the flowchart of FIG. 38, the controller 100 provided in the ADF 51 of the fifth embodiment first determines whether or not the document MS is sensed by all of the plurality of target length sensors S4. That is, it is determined whether or not the length of the document MS on the document placement table 53 is longer than the maximum length L1−N (L1max).
If it is determined that the length of the document MS on the document table 53 is longer than L1max ("Y" at the branch in FIG. 38), the call is triggered by the trailing edge detection of the document MS by the separation sensor S3. Control to start operation.
On the other hand, when it is determined that the length of the document MS on the document placement table 53 is shorter than L1max ("N" at the branch in FIG. 38), which of the plurality of L1-N has the length of the document MS? To determine whether it is true. This determination is made when the original MS is detected by the (N-1) th target length sensor S4- (N-1) and is not detected by the Nth target length sensor S4-N. The length is determined as L1-N.
Then, based on the determination result, the tip detection sensor S1 and the pickup lowering start sensor S2 used for tip detection are determined.

As a specific example, in the case of the fifth embodiment, when both the first target length sensor S4-1 and the second target length sensor S4-2 detect the document MS, the length of the document MS should increase productivity. It is determined that the size is not the target size, and control is performed so that the calling operation is started by using the trailing edge detection of the document MS by the separation sensor S3 as a trigger.
When the document MS is detected by the first target length sensor S4-1 and the document MS is not detected by the second target length sensor S4-2, the length of the document MS is determined as L1-2, It is determined that tip detection is performed by the two pickup lowering start sensor S2-2 and the second tip detection sensor S1-2. If neither the first object length sensor S4-1 nor the second object length sensor S4-2 senses the document MS, the length of the document MS is determined as L1-1, and the first pickup descending starts. It is determined that the tip detection is performed by the sensor S2-1 and the first tip detection sensor S1-1.

After the pickup lowering start sensor S2 and the front end detection sensor S1 used for the front end detection are determined, the same control as that in the second embodiment is performed as the drive timing of each motor, toward the fixed image reading unit 300. Document MS is continuously conveyed.
The timing at which the next document MS2 can be started after the previous document MS1 on the document table 53 starts to be transported varies depending on the length of the document MS, but the length of the document MS as in the fifth embodiment. Accordingly, by determining the leading edge detection sensor S1 serving as a trigger for the calling operation, it is possible to set so that the next original MS2 can be started at a timing corresponding to the length of the original. As a result, a plurality of sizes can be set as targets to increase productivity.
Further, the timing suitable for bringing the pickup roller 80 once separated from the original document MS1 into contact with the original on the original table 53 again depends on the length of the original MS. This is because when the pickup roller 80 is brought into contact with the front document MS1 at the same timing as the case of the short document MS when the long document MS is conveyed after the conveyance of the previous document MS1 is started. Becomes longer. When the time for which the pickup roller 80 is in contact with the previous document MS1 becomes long, the pickup roller 80 is kept away from the upper surface of the document MS every time one document MS is fed. Similarly, it is disadvantageous for problems such as double feeding and document smearing. For this reason, the appropriate installation position of the pickup lowering start sensor S2 varies depending on the length of the document MS. As in the fifth embodiment, the pickup lowering start sensor S2 that triggers the lowering operation of the pickup roller 80 is determined according to the length of the document MS, so that the pickup roller 80 is lowered at a timing corresponding to the length of the document. Can be set to start. As a result, it is possible to set a plurality of target sizes for which productivity should be improved while preventing double feed and document smearing.

In FIG. 39, the double feed detection sensor S5 similar to the ADF 51 of the above modification is arranged on the ADF 51 of the fifth embodiment in which a plurality of tip detection sensors S1, target length sensors S4, and pickup lowering start sensors S2 are provided. It is explanatory drawing of a structure.
Also in the configuration shown in FIG. 39, as in the above modification, when the double feed detection sensor S5 detects the double feed state, the separation sensor S3 detects that the trailing edge of the front document MS1 has passed through the separation nip portion. Later, driving of the pickup transport motor 115 and the paper feed motor 102 is started. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.

Like the ADF 51 having the configuration shown in FIG. 39, the multi-feed detection sensor S5 is provided, and in the non-multi-feed state, the calling operation is performed immediately after detection by the leading edge detection sensor S1-N determined based on the document length. FIG. 40 shows a flowchart of control for determining a trigger for starting conveyance of the next original MS2.
As shown in the flowchart of FIG. 40, in the ADF 51 having the configuration shown in FIG. 39, when the document MS is detected by all the plurality of target length sensors S4, and when the double feed is detected by the double feed detection sensor S5. Controls the start of the conveyance of the next original MS2 triggered by the detection of the trailing edge of the previous original MS1 by the separation sensor S3.
On the other hand, if it is determined that the length of the document MS on the document table 53 corresponds to any one of L1-1 to L1-N and the next document MS2 is not double-fed, the length L1- Control is performed so as to start the calling operation with the leading edge detection of the document MS by the leading edge detection sensor S1-N corresponding to N as a trigger.

Example 6
Next, a sixth example (hereinafter referred to as Example 6) of the ADF 51 of the present embodiment including the tip detection sensor S1 will be described.
FIG. 41 is a schematic explanatory diagram up to the middle of the document setting unit A, the separation conveyance unit B, the registration unit C, and the turn unit D of the ADF 51 according to the sixth embodiment.
Similar to the ADF 51 of the fourth and fifth embodiments, the ADF 51 of the sixth embodiment is configured to include two target length sensors S4. However, unlike these embodiments, there is one tip detection sensor S1. . The information of the predetermined time tb [s] from when the leading edge of the previous original MS1 is detected by the leading edge detection sensor S1 to when the calling operation for carrying the next original MS2 is started is two patterns. It is stored in a storage unit (not shown). That is, the ADF 51 of the third embodiment has only one information on the target length sensor S4 and the predetermined time tb [s], whereas the ADF 51 of the sixth embodiment has a plurality of target length sensors S4. .., N, and the same number of predetermined time tb [s] information corresponding to each of them, tb-1-1, 2, 3,. It is the structure preserve | saved at the memory | storage part not shown.
The ADF 51 according to the sixth embodiment has a configuration in which a plurality of sizes of objects whose productivity should be increased can be set as in the fourth and fifth embodiments. In the example illustrated in FIG. 41, two types of sizes can be set.

FIG. 42 is a control flowchart for determining a trigger for a call operation having a configuration in which a plurality of target length sensors S4 are provided and a plurality of pieces of information of a predetermined time tb [s] are stored, like the ADF 51 of the sixth embodiment. is there. The calling operation here may be configured to start the rotational drive of the pickup roller 80 in contact with the original MS, or the lowering operation of the pickup roller 80 in a state of being separated from the original MS may be started. Then, the structure which starts rotation drive may be sufficient.
As shown in the flowchart of FIG. 42, the controller 100 included in the ADF 51 of the sixth embodiment first determines whether or not the document MS is sensed by all the plurality of target length sensors S4. That is, it is determined whether or not the length of the document MS on the document placement table 53 is longer than the maximum length L1−N (L1max).
If it is determined that the length of the document MS on the document table 53 is longer than L1max (“Y” at the branch in FIG. 42), the call is triggered by the detection of the trailing edge of the document MS by the separation sensor S3. Control to start operation.
On the other hand, when it is determined that the length of the document MS on the document placement table 53 is shorter than L1max (“N” at the branch in FIG. 42), which of the plurality of L1-N has the length of the document MS? To determine whether it is true. This determination is made when the original MS is detected by the (N-1) th target length sensor S4- (N-1) and is not detected by the Nth target length sensor S4-N. The length is determined as L1-N.
Based on the determination result, a predetermined time tb [s] from when the tip is detected by the tip detection sensor S1 to when the calling operation is started is determined.

As a specific example, in the case of the sixth embodiment, when both the first target length sensor S4-1 and the second target length sensor S4-2 detect the document MS, the length of the document MS should increase productivity. It is determined that the size is not the target, and control is performed so that the calling operation is started by using the trailing edge detection of the document MS by the separation sensor S3 as a trigger.
When the document MS is detected by the first target length sensor S4-1 and the document MS is not detected by the second target length sensor S4-2, the length of the document MS is determined as L1-2, and is determined in advance. It is determined that tb-2 longer than tb-1 is used as the time tb [s]. When neither the first target length sensor S4-1 nor the second target length sensor S4-2 senses the document MS, the length of the document MS is determined as L1-1, and the predetermined time tb [ As s], it is decided to use a shorter time tb-1.

After determining the predetermined time tb [s] from when the tip is detected by the tip detection sensor S1 to when the calling operation is started, the same control as in the above-described third embodiment is performed as the drive timing of each motor. The document MS is continuously conveyed toward the fixed image reading unit 300.
The timing at which the next document MS2 can be started after the previous document MS1 on the document table 53 starts to be transported varies depending on the length of the document MS, but the length of the document MS as in the sixth embodiment. Accordingly, by determining a predetermined time tb [s] from the detection of the leading edge by the leading edge detection sensor S1 to the start of the calling operation, the next document MS2 starts to be conveyed at a timing according to the length of the document. Can be set to be able to. As a result, a plurality of sizes can be set as targets to increase productivity.

In FIG. 43, a plurality of target length sensors S4 are provided, and a double feed detection sensor S5 similar to the ADF 51 of the above modification is arranged in the ADF 51 of the sixth embodiment in which a plurality of pieces of information of a predetermined time tb [s] are stored. It is explanatory drawing of a structure.
In the configuration shown in FIG. 43, as in the above modification, when the double feed detection sensor S5 detects the double feed state, the separation sensor S3 detects that the trailing edge of the front document MS1 has passed through the separation nip portion. Later, driving of the pickup transport motor 115 and the paper feed motor 102 is started. As a result, even when the next original MS2 overlaps with the previous original MS1 and is pulled to the vicinity of the separation nip portion, the subsequent original MS2 does not overlap with the previous original MS1 after the transport operation of the next original MS2 by the pickup roller 80. Can be controlled.

Like the ADF 51 having the configuration shown in FIG. 43, the multi-feed detection sensor S5 is provided. In the non-multi-feed state, a predetermined time tb [s] determined based on the document length elapses after detection by the leading edge detection sensor S1. FIG. 44 shows a flowchart of control for determining a trigger for a call operation having a configuration in which the call operation is performed thereafter.
As shown in the flowchart of FIG. 44, in the ADF 51 having the configuration shown in FIG. 43, when the document MS is detected by all of the plurality of target length sensors S4, and when the double feed is detected by the double feed detection sensor S5. Controls the start of the conveyance of the next original MS2 triggered by the detection of the trailing edge of the previous original MS1 by the separation sensor S3.
On the other hand, if it is determined that the length of the document MS on the document table 53 corresponds to any of L1-1 to L1-N and the next document MS2 is not double-fed, the document MS by the leading edge detection sensor S1. Control is performed so that the call operation is started after a predetermined time tb [s] has elapsed, using the detection of the leading edge as a trigger.

In the ADF 51 of the above-described embodiment, the document calling member is brought into contact with and separated from the document on the document placing table, and the document calling member is moved to the document by raising and lowering the pickup roller 80 as the document calling member. It is the structure which touches / separates to. The configuration in which the original calling member is brought into contact with and separated from the original on the original placing table is not limited to such a configuration, and the original placing table on which a bundle of originals is placed at a position facing the original calling member. The document calling member disposed above may be brought into contact with or separated from the upper surface of the document by raising and lowering the document. In the case of such a configuration, at the timing when the pickup roller 80 in each example of the above-described embodiment is raised, the document placing table is controlled to be lowered, and the document calling member is separated from the upper surface of the document. Further, in each of the above-described embodiments, control is performed to raise the document placing table at the timing when the pickup roller 80 is lowered, and the document calling member is brought into contact with the upper surface of the document. Further, the document calling member may be brought into contact with and separated from the document by raising and lowering the document calling member and raising and lowering the document placing surface.
In this way, the configuration for raising and lowering the document placement surface is similar to the configuration for raising and lowering the pickup roller 80 after the document placement surface starts to rise in order to bring the document calling member into contact with the document. A predetermined time is required until the document calling member contacts the document. Therefore, as in the conventional image reading apparatus, if the rising of the document placement surface starts after detecting that the trailing edge of the preceding document has passed through the separation nip portion, the trailing edge of the preceding document is If the predetermined time from the start of raising the document placing surface until the document calling member comes into contact with the document does not elapse after the document passes through the section and becomes ready for conveyance, Cannot be started. As a result, it has been difficult for the conventional image reading apparatus to narrow the gap between sheets as the predetermined time elapses. On the other hand, by performing control to raise the document table at the timing of lowering the pickup roller 80 of the present embodiment, the document table can be started to rise before the next document can be conveyed, Even if the ascending operation takes the same predetermined time as the conventional one, the time until the next original can be conveyed and the actual conveyance starts can be shortened. You can narrow the gap.
That is, as in the present embodiment, the operation of bringing the pickup roller 80 and the document MS into contact with each other based on a new trigger that is the leading edge detection of the document MS can be started, and the space between the sheets can be reduced. Transport productivity can be improved.

In the above-described embodiment, the pickup roller 80 is used as the document calling member. However, the document calling member may be configured to be used as a member constituting the separation conveyance unit. In this configuration, the document calling member and the document on the document mounting table are brought into contact with each other by pressing the mounting surface side of the document mounting table against the transport member constituting the separation transport unit. Referring to the ADF 51 of the present embodiment shown in FIG. 1, the conveying member that does not include the pickup roller 80 and constitutes the separation conveying unit with the upper surface of the document MS on the document placing table 53 by raising and lowering the movable document table 53b. Is controlled to contact and separate from the paper feed belt 84. In the case of this configuration, even if the same predetermined time is required for the ascending operation by starting the ascent of the movable manuscript table 53b before the trailing edge of the front manuscript MS1 passes through the separation nip portion of the separation conveyance unit. The time from when the next original can be transported to when it is actually transported can be shortened, and the sheet space can be narrowed to the conventional image reading apparatus.
As described above, in the configuration in which the contact and separation between the paper feeding belt 84 and the original are controlled by raising and lowering the movable original table 53b, the next original MS2 is supplied while the previous original MS1 passes through the separation nip portion. When the paper belt 84 comes into contact, the conveyance of the next original MS2 is started by the paper feed belt 84 whose surface moves in accordance with the conveyance of the previous original MS1. For this reason, if there is a possibility that double feeding may occur when the conveyance of the next original MS2 is started in a state where the previous original MS1 remains in the separation nip portion, the upper surface of the next original MS2 on the original placement table 53 is the feed belt. When it comes into contact with 84, the movable document table 53b starts to rise so that the rear end of the preceding document MS1 passes through the separation nip portion.

  In the above-described embodiment, the example in which the present invention is applied to the sheet material conveying device of the image reading unit 50 that is an image reading device has been described. The sheet material conveying device including the characterizing portion of the present invention is not limited to this, and may be a sheet material conveying device that continuously conveys a sheet material from a sheet material accommodating portion that accommodates a plurality of sheet materials in a stacked manner. If applicable. For example, the present invention is also applicable to a transfer paper supply device 40 that conveys transfer paper as a sheet material.

As described above, the ADF 51, which is the sheet material conveying apparatus of the present embodiment, has a document setting unit A that is a sheet material accommodating unit that accommodates a plurality of document materials MS, and a document MS at a predetermined conveyance target position. And a document conveying unit 54 which is a sheet material conveying unit that conveys to a certain first reading conveyance unit E. In addition, the sheet material conveying device applies a conveying force toward the document conveying unit 54 to the uppermost document MS which is the outermost one of the documents MS on the document placing table 53 of the document setting unit A. Then, a pickup roller 80 constituting sheet material calling means for calling the uppermost original MS from a plurality of originals MS, and a single original MS with a conveying force applied to the pickup roller 80 overlap with the original conveying unit 54. The separation conveyance unit B which is a separation unit that separates another document MS to be directed to the document from one document MS and directs only one document MS to the document conveyance unit 54 and the sheet material calling unit are controlled. And a controller 100 which is a sheet material calling control means. Further, when the sheet material calling means receives a call start signal transmitted from the controller 100, the sheet material calling means starts a call operation for applying a conveying force to one original MS, and picks up after starting the call operation. This is a configuration that requires a predetermined rise time before the roller 80 starts to convey one original MS. Further, in the ADF 51, after the conveyance force is applied to one original MS, the conveyance force is applied by the pickup roller 80 before the conveyance force is applied to the next original MS. To stop. Then, a leading edge detection unit that detects a leading edge in the conveyance direction of the document MS conveyed at a predetermined position in the document conveying portion 54 and transmits a leading edge detection signal to the controller 100 when the leading edge is detected. The controller 100 includes the sensor S1, and transmits a calling start signal to the sheet material calling unit at a predetermined timing based on the leading edge detection signal. Therefore, the sheet is triggered by the fact that the leading edge of the previous document MS1 of the two documents MS (the previous document MS1 and the next document MS2) conveyed in succession has reached a predetermined position in the document transport unit 54. The pickup roller 80 of the material calling means starts a calling operation for carrying the next original MS2. For this reason, at the timing before the trailing edge of the previous document MS1 reaches the downstream position of the separation nip portion, which is a position where the occurrence of double feeding can be prevented even when the pickup roller 80 starts to apply the conveying force to the next document MS2. Thus, it is possible to set a trigger for starting the calling operation. As a result, as compared with the conventional configuration, the next original MS2 is started after the trailing edge of the previous original MS1 reaches the downstream position of the separation nip portion and the rising time further elapses. The time lag after the MS2 can be started can be shortened. Further, the timing when the predetermined rising time has elapsed after the sheet material calling means receives the calling signal is the timing after the trailing edge of the front document MS1 reaches the downstream position of the separation nip portion. By setting a predetermined timing at which the controller 100 transmits the call start signal, it is possible to prevent occurrence of double feeding. As described above, according to the ADF 51 of the present embodiment, it is possible to narrow the gap between the sheets by reducing the time lag compared to the conventional one while preventing the double feeding of the two documents MS that are continuously conveyed. it can.
In the ADF 51 of this embodiment, a pickup roller 80, a pickup conveyance motor 115 that transmits rotational driving to the pickup roller 80, a pickup contact / separation mechanism (not shown) for raising and lowering the pickup roller 80, and a pickup contact A sheet material calling means is constituted by a pickup lifting / lowering motor 101 that transmits drive to the separation mechanism to raise and lower the pickup roller 80.

Further, the ADF 51 according to the modified example has a trailing end in the transport direction of the document MS that is transported at a predetermined position downstream of the separation nip portion in the transport direction of the document MS from the separation nip portion where the separation action of the separation transport unit B works. And a separation sensor S3 that transmits a trailing edge detection signal to the controller 100 when the trailing edge is detected, and a double feed detection that detects whether or not a double feed of the document MS has occurred in the vicinity of the separation nip portion. A double feed detection sensor S5 as means. When the double feed detection sensor S5 detects the occurrence of double feed, the controller 100 sends a call start signal at a predetermined timing after receiving the trailing edge detection signal to the pickup lift motor 101 that constitutes the sheet material calling means. And to the pickup conveyance motor 115.
In the ADF 51 of the present embodiment, the double feeding is prevented from occurring due to the separation action by the paper feeding belt 84 and the reverse roller 85 of the separation conveyance unit B, but the double feeding still occurs in the vicinity of the separation nip portion. Can happen. Then, when double feed occurs in the vicinity of the separation nip portion and the next original MS2 passes through the separation nip portion together with the previous original MS1, the double feed is made to the turn portion D and the two reading portions downstream thereof, resulting in a read image. May cause adverse effects.
For such a problem, the modified ADF 51 has a double feed detection sensor S5 that can detect whether the previous original MS1 and the next original MS2 overlap in the vicinity of the separation nip portion. As a result, if the next original MS2 is pulled to the previous original MS1 more than expected, it is determined that the previous original MS1 and the next original MS2 cannot be separated by the detection signal of the double feed detection sensor S5. The timing at which the conveying force is applied to the next original MS2 by the pickup roller 80 is controlled by the rear end detection signal from the separation sensor S3 based on the signal indicating that the separation is not performed. That is, when a double feed occurs in the separation nip portion, the trailing edge detection is detected instead of the leading edge detection of the previous document MS1 based on the double feed detection signal from the double feed detection sensor S5 in the separation nip portion. By selecting it as a trigger for the calling operation of the document MS2, it is possible to prevent the feeding force from being applied before the next document MS2 is separated from the previous document MS1. Accordingly, it is possible to prevent the next original MS2 from being fed to the turn part D and two reading parts downstream thereof without being separated from the previous original MS1, resulting in a problem that adversely affects the read image.

As the double feed detection sensor S5, by using the ultrasonic detection sensor including the ultrasonic transmission unit S5-1 and the reception unit S5-2 described in the modification, the previous document is detected at the detection position of the double feed detection sensor S5. It can be determined whether or not the MS1 and the next original MS2 overlap each other.
Further, as the double feed detection sensor S5, even when a light transmission type detection sensor including a light emitting portion and a light receiving portion is used, the previous original MS1 and the next original MS2 overlap at the detection position of the double feed detection sensor S5. It is possible to determine whether or not

Further, in the ADF 51 of the present embodiment, as sheet material length information input means for inputting sheet material length information, which is information on the length of the document MS placed on the document placing table 53 in the conveyance direction, to the controller 100. The controller 100 has a target length sensor S4, and the controller 100 determines that the length of the document MS set on the document table 53 based on the detection result of the target length sensor S4 is within a predetermined range, and the document MS increases productivity. If it is determined that the size is to be increased, a calling start signal is transmitted to the sheet material calling means at a predetermined timing based on the leading edge detection signal of the leading edge detection sensor S1. In this way, by providing a configuration for inputting sheet material length information, when the size of the original MS is a size that should increase productivity, such as A4 paper or B5 paper, the paper space is narrower than before. The highly productive original MS can be conveyed.
Note that the controller 100 of the ADF 51 of the present embodiment determines whether the size of the document MS is a target size that should increase productivity based on the detection result of the target length sensor S4. Alternatively, the user may operate the operation unit 108 to input the size of the document MS placed on the document placement table 53.
Note that, like the ADF 51, a target length sensor S4, which is a sheet material length detection unit that detects the length of the document MS placed on the document placement table 53 of the document setting unit A in the conveyance direction, is provided. The sensor S4 functions as a sheet material length information input unit, thereby improving user operability. In this case, it is determined whether or not the size of the document MS is a target size for which productivity should be improved only by the user setting the document MS on the document placement table 53, and the user determines the document MS with the operation unit 108. This is because it is not necessary to enter the size.

  In the configuration in which the double feed detection sensor S5 is arranged in the ADF 51 of the present embodiment, even when the controller 100 determines that the document MS is the target size for which productivity should be improved, the double feed detection sensor. When S5 detects double feeding, the conveyance of the next original MS2 is started based on the trailing edge detection signal of the previous original MS1 of the separation sensor S3. Thereby, it is possible to prevent problems caused by double feeding while conveying the highly productive document MS.

  In addition, the ADF 51 of the present embodiment is conveyed at a predetermined position downstream of the separation direction of the original MS from the separation nip portion where the separation action is performed by the paper feeding belt 84 and the reverse roller 85 of the separation conveyance portion B. It has a separation sensor S3 which is a rear end detecting means for detecting the rear end of the incoming document MS in the transport direction and transmitting a rear end detection signal to the controller 100 when the rear end is detected. Based on the detection result of the target length sensor S4, the controller 100 determines that the length of the document MS placed on the document table 53 in the transport direction is within a predetermined range, and the document MS should be improved in productivity. If it is determined that the size of the sheet is determined, the calling start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the leading edge detection signal. On the other hand, when it is determined that the length in the transport direction of the document MS placed on the document placement table 53 is outside the predetermined range and the document MS is not the target size for improving productivity, the trailing edge detection signal A call start signal is transmitted to the sheet material calling means at a predetermined timing after reception of. With such a configuration, when the document MS has a target size for which productivity should be improved, it is possible to realize transport of the highly productive document MS with a gap between sheets. Further, since the calling operation is started based on the trailing edge detection signal when the document MS is not the target size, even if the document MS is not the target size, the document MS is continuously conveyed without causing double feeding. Can be done.

  Further, in the ADF 51 according to the fourth and fifth embodiments, two leading edge detection sensors are used as a plurality of leading edge detection means so that the leading edge in the conveyance direction of the sheet material conveyed at a plurality of positions in the document conveying portion 54 can be detected. S1 (first tip detection sensor S1-1, second tip detection sensor S1-2) is provided. Furthermore, two target length sensors S4 for determining whether the size of the document MS is a target size that should improve productivity are provided on the document placement table 53 (first target length sensor S4-1). Second target length sensor S4-2). Then, if the controller 100 determines that the size of the document MS is a short size among the target sizes for which productivity should be improved based on the detection results of the two target length sensors S4, the first tip detection sensor S1-1 is selected, and a calling start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the leading edge detection signal from the selected first leading edge detection sensor S1-1. Further, when it is determined that the size of the document MS is a long size among the target sizes for which productivity is to be improved, the second leading edge detection sensor S1-2 is selected, and the selected second leading edge detection sensor S1-2 is selected. A call start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the leading edge detection signal. Accordingly, by selecting the trigger leading edge detection sensor S1 that minimizes the timing at which the conveyance of the next original MS2 is started while preventing the double feed according to the sizes of the objects for which the productivity should be increased. It is possible to continuously convey the original MS with the gaps between the sheets.

  Further, in the ADF 51 of the sixth embodiment, the controller 100 stores information (tb-1, tb-2) of two patterns of predetermined times tb [s] as information of a plurality of predetermined times tb [s]. A storage unit (not shown). Then, when the controller 100 determines that the size of the document MS is a short size (L1-1) among the target sizes for which productivity should be improved based on the detection results of the two target length sensors S4, Tb-1 is selected as the predetermined time, and a call start signal is transmitted to the sheet material calling means at a selected predetermined timing (after elapse of tb-1) after receiving the leading edge detection signal. Further, when it is determined that the size of the document MS is a long size (L1-2) among the target sizes for which productivity is to be improved, tb-2 is selected as a predetermined time, and the leading edge detection signal is received. A call start signal is transmitted to the sheet material calling means at a predetermined timing selected (after elapse of tb-2). Further, as in the sixth embodiment, if the control is performed to start the calling operation after a predetermined time (tb [s]) has elapsed since the front end detection of the front end detection sensor S1, the separation nip portion is set by setting the predetermined time. The distance from the detection position to the detection position of the tip detection sensor S1 can be set freely to some extent. For this reason, there exists an advantage that the freedom degree of the installation position of front-end | tip detection sensor S1 spreads.

Further, in the ADF 51 according to the first or fourth embodiment, the sheet material calling unit is driven in a state in which the sheet material calling unit is in contact with the uppermost document MS of the plurality of documents MS placed on the document placing table 53. Accordingly, a pickup roller 80 which is a sheet material calling member for applying a conveying force to the single document MS, and a sheet material calling for bringing the pickup roller 80 into or out of contact with the document MS on the document placement table 53. A pickup contact / separation mechanism (not shown) which is a member contact / separation mechanism. Further, the sheet material calling unit includes a pickup conveyance motor 115 that transmits rotational driving to the pickup roller 80 and a pickup lifting / lowering motor 101 that transmits the driving to the pickup contact / separation mechanism and moves the pickup roller 80 up and down. When the sheet material calling means receives the calling start signal, as the calling operation, first, the pickup contact / separation mechanism drives the pickup lifting / lowering motor 101 to bring the pickup roller 80 into contact with the document MS on the document placing table 53. Then, the pickup roller 80 is moved from the “separated” state to the “contacted” state. Next, in order to drive the pickup roller 80 that has come into contact with the document MS, the pickup conveyance motor 115 starts to be driven. That is, in these ADFs 51, the pickup roller 80 is separated from the original MS every time one original MS is conveyed, and the pickup roller 80 starts to descend based on a predetermined trigger for conveying the next original MS. Thereafter, the pickup roller 80 starts to rotate. With such a configuration, when the predetermined trigger is the trailing edge detection of the previous document MS1 in the separation sensor S3, the previous document MS1 passes through the separation conveyance unit B and can start conveyance of the next document MS2. Further, since it takes time for the calling operation to rise, which is the time for lowering the pickup roller 80 and the time for rotating the pickup roller 80, the previous original MS1 continues to be conveyed during that time, and the space between the sheets is increased. On the other hand, in the ADF 51 according to the first or fourth embodiment, the leading document sensor MS1 detects the leading edge of the preceding document MS1, and then the leading document MS1 can pass through the separating and conveying unit B and start conveying the next document MS2. It is possible to absorb at least a part of the rise time of the call operation during the time until As a result, the conveyance of the next original MS2 can be started as compared with the configuration in which the conveyance of the next original MS2 is started after elapse of the startup time of the calling operation after the state where the conveyance of the next original MS2 can be started. Then, the time from when the next original MS2 starts to be conveyed can be shortened. Thereby, the space between the sheets can be narrowed, and the productivity of continuous conveyance of the document MS can be improved.
Note that the height at which the pickup roller 80 abuts on the original MS differs depending on the number of originals MS on the original placing table 53. For this reason, when a torque limiter (not shown) is provided in the drive transmission unit from the pickup lifting / lowering motor 101 to the pickup contact / separation mechanism, when the number of documents MS is large and the height at which the pickup roller 80 contacts the document MS is high. Therefore, it is possible to prevent an excessive contact pressure from being applied.

Further, in the ADF 51 according to the second and fifth embodiments, the leading edge detection sensor S1 transports the document MS at a predetermined position in the document transport section 54 on the upstream side in the transport direction of the document MS with respect to the leading edge detection position where the leading edge of the document MS is detected. It has a pickup lowering start sensor S2 which is an upstream leading edge detection means for detecting the leading edge of the incoming document MS in the conveying direction and transmitting an upstream leading edge detection signal to the controller 100 when the leading edge is detected. Further, the sheet material calling means of the ADF 51 is driven in a state in which it is in contact with the uppermost one original MS of the plurality of originals MS placed on the original placement table 53, thereby making the one original. A pickup roller 80 that is a sheet material calling member that applies a conveying force to the MS, and a sheet material calling member contacting / separating mechanism that brings the pickup roller 80 into contact with or away from the document MS on the document placement table 53 (not shown). Pickup pickup / separation mechanism. Further, the sheet material calling unit includes a pickup conveyance motor 115 that transmits rotational driving to the pickup roller 80 and a pickup lifting / lowering motor 101 that transmits the driving to the pickup contact / separation mechanism and moves the pickup roller 80 up and down. Then, the controller 100 transmits a paging preparation signal for performing a preparatory operation before the paging operation to the pickup lifting / lowering motor 101 of the sheet material paging means at a predetermined timing based on the upstream end detection signal. When the pickup lifting / lowering motor 101 of the sheet material calling means receives the call preparation signal, a pickup contact / separation mechanism (not shown) performs an operation of bringing the pickup roller 80 into contact with the document MS on the document placement table 53 as a preparation operation. Therefore, the pickup lifting / lowering motor 101 is driven to start moving the pickup roller 80 from the “separated” state to the “abutted” state. Thereafter, when the pickup conveying motor 115 of the sheet material calling means receives the calling start signal, the pickup conveying motor 115 starts driving to execute the operation of rotating the pickup roller 80 in contact with the document MS as the calling operation. To do.
In this way, by providing the trigger for the operation of lowering the pickup roller 80 before the leading edge detection by the leading edge detection sensor S1 serving as a trigger for the calling operation for starting the driving of the pickup conveyance motor 115, the leading edge detection sensor S1 performs the operation. It is possible to perform control that does not include the time required for the pickup roller 80 to be lowered in the calling operation rising time after the tip detection. As the ADF 51, the time from when the leading edge detection sensor S1 detects the leading edge of the previous original MS1 to when the conveyance of the next original MS2 can be started is very short. There may be a case where the time combined with the rotation time cannot be absorbed. Even in such a case, the pickup roller 80 starts to move down before the leading edge of the previous document MS1 is detected by the leading edge detection sensor S1, as in the second and fifth embodiments. The time required for the descent of 80 does not affect the extension of the interval between the sheets, and it is possible to prevent the productivity from being lowered due to the descent operation.

  Further, in the ADF 51 of this embodiment, the sheet material calling means is the uppermost one original MS of the plurality of originals MS accommodated on the original placement table 53 of the original setting portion A which is a sheet material accommodating portion. A pickup roller 80, which is a sheet material calling member that applies a conveying force to the single document MS by being rotationally driven while being in contact with the sheet, is provided. Then, when the pickup conveying motor 115 of the sheet material calling means receives the calling start signal, the pickup conveying motor 115 starts driving in order to execute an operation of rotating the pickup roller 80 in contact with the document MS as a calling operation. To do. In such an ADF 51, the pickup conveyance motor 115, which is the start-up time of the calling operation, is from the time when the leading edge detection sensor S1 detects the leading edge of the previous original MS1 to the time when the conveyance of the next original MS2 can be started. It is possible to absorb at least a part of the time from the start of driving until the pickup roller 80 starts to apply the conveying force to the document MS. As a result, the conveyance of the next original MS2 can be started as compared with the configuration in which the conveyance of the next original MS2 is started after elapse of the startup time of the calling operation after the state where the conveyance of the next original MS2 can be started. Then, the time from when the next original MS2 starts to be conveyed can be shortened. Thereby, the space between the sheets can be narrowed, and the productivity of continuous conveyance of the document MS can be improved.

  The sheet material calling means of the ADF 51 according to the embodiment includes a pickup material contacting / separating mechanism (not shown) that is a sheet material calling member contacting / separating mechanism for bringing the pickup roller 80 into contact with or separating from the document MS on the document placing table 53. . Then, after the front document MS1 is transported to the pickup roller 80 and reaches a region where the transport force is applied to other transport members such as the paper feed belt 84, the transport force is applied by the pickup roller 80 of the front document MS1. The pickup contact / separation mechanism performs an operation of separating the pickup roller 80 from the document MS on the document placement table 53 at a predetermined timing before passing through the area to be provided. Thereby, the application of the conveying force to the document MS by the sheet material calling unit is stopped, and the occurrence of double feeding due to the continuous application of the conveying force from the pickup roller 80 to the previous document MS1 and the next document MS2 is prevented. is doing. Further, when the application of the conveying force from the pickup roller 80 to the document MS is stopped, the pickup roller 80 is separated from the document MS, and thus the pickup roller 80 remains in contact with the document MS. It is possible to prevent document smearing and double feeding.

  In the ADF 51 according to the first and fourth embodiments, when the pickup raising / lowering motor 101 and the pickup conveying motor 115 of the sheet material calling unit receive the calling start signal, the pickup roller 80 is first “separated” as the calling operation. The pickup lifting / lowering motor 101 is driven so as to move from the state to the “contact” state, and the pickup contact / separation mechanism performs an operation of bringing the pickup roller 80 into contact with the document MS on the document placement table 53. . Thereafter, driving of the pickup conveyance motor 115 is started, and an operation of rotationally driving the pickup roller 80 in contact with the document MS is executed. As described above, in the configuration in which the sheet material calling means performs the lowering operation of the pickup roller 80 and the rotation operation of the pickup roller 80 after receiving the call start signal, the next original MS is conveyed from the trigger of the call start signal. It is difficult to shorten the time lag until the start. For this reason, as in the conventional image reading apparatus, if the trailing edge detection of the previous original MS1 is used as a trigger for the call start signal, even if the next original MS2 starts to be conveyed, the double feed does not occur and the next is actually started. A time lag occurs before the document MS2 starts to be conveyed, and it is difficult to narrow the gap between the sheets. On the other hand, in the ADF 51 according to the first and fourth embodiments, the pickup roller 80 starts to descend using the leading edge detection by the leading edge detection sensor S1 as a trigger. Therefore, the leading edge of the previous document MS1 at the leading edge detection sensor S1. It is possible to absorb at least a part of the start-up time of the call operation during the time from the detection until the conveyance of the next original MS2 can be started. As a result, the conveyance of the next original MS2 can be started as compared with the configuration in which the conveyance of the next original MS2 is started after elapse of the startup time of the calling operation after the state where the conveyance of the next original MS2 can be started. Then, the time from when the next original MS2 starts to be conveyed can be shortened. Thereby, the space between the sheets can be narrowed, and the productivity of continuous conveyance of the document MS can be improved.

  An image including a document conveying unit that conveys a document MS as a sheet material, and a first fixed reading unit 151 and a second fixed reading unit 95 that are reading units that read a document image of the document MS conveyed by the document conveying unit. In the image reading unit 50 which is a reading apparatus, the ADF 51 described in the first to sixth embodiments can be used as the document conveying unit, so that the space between the conveyed documents MS can be reduced. The productivity when reading can be improved.

  In the copier 500 that is an image forming apparatus including an image reading unit and an image forming unit 1 that forms an image based on a document image read by the image reading unit, the image reading unit according to the first embodiment is used. Since the image reading unit 50 including the ADF 51 described in the above items 6 to 6 can improve the productivity when continuously reading a document, the productivity when continuously copying is improved. be able to.

DESCRIPTION OF SYMBOLS 1 Image forming part 2 Optical writing device 3 Process unit 4 Photoconductor 5 Charging device 6 Developing device 7 Agitating unit 8 Conveying screw 9 Developing case 10 Toner density sensor 11 Developing unit 12 Developing sleeve 13 Magnet roller 14 Doctor blade 15 Drum cleaning device 16 Cleaning blade 17 Fur brush 18 Electric field roller 19 Scraper 20 Recover screw 21 Recycle transport device 22 Static elimination lamp 24 Transfer unit 25 Intermediate transfer belt 26 Primary transfer roller 27 Lower stretch roller 28 Paper transport unit 29 Paper transport belt 30 Drive roller 31 Two Next transfer roller 33 Registration roller pair 34 Fixing device 35 Paper discharge roller pair 36 Switchback device 37 Main body side transfer paper feed path 40 Transfer paper feed device 41 Paper bank 42 Transfer paper feed cassette 43 Transfer paper feed roller 4 transfer sheet feed path 45 transfer paper separating roller 47 conveying rollers 48 feed port 50 the image reading unit 51 ADF
52 Main body cover 53 Document placing table 53a Fixed document table 53b Movable document table 54 Document conveying section 55 Document stacking table 57 Medium size length sensor 58 Large size length sensor 59 Table lift sensor 61 Paper discharge sensor 62 Set filler 63 Document set sensor 65 Registration sensor 66 Intermediate roller pair 67 Reading entrance sensor 72 Abutting sensor 73 Document width sensor 80 Pickup roller 82 Drive roller 83 Driven roller 84 Paper feed belt 85 Reverse roller 86 Pull-out roller pair 90 Reading entrance roller pair 92 Reading exit roller pair 93 Second reading exit roller pair 94 Discharge roller pair 95 Second fixed reading unit 96 Second reading roller 100 Controller 101 Pickup lifting motor 102 Paper feed motor 103 Reading motor 104 Paper discharge motor 105 Bottom plate raising motor 07 I / F
108 Operation unit 111 Main body control unit 113 Pull-out motor 114 Reading entrance motor 115 Pickup transport motor 150 Scanner 151 First fixed reading unit 152 Moving reading unit 153 Image reading sensor 154 First contact glass 155 Second contact glass 158 Copy start button 159 Hinge 300 Fixed Image Reading Unit 400 First Reading Position 500 Copier 501 Discharge Tray A Document Setting Unit B Separation / Conveying Unit C Registration Unit D Turn Unit E First Reading / Conveying Unit F Second Reading / Conveying Unit G Paper Discharging Unit H Stack Unit J Document leading edge set position L Laser beam MS Document MS1 Previous document MS2 Next document P Transfer paper S1 Lead detection sensor S1-1 First leading edge detection sensor S1-2 Second leading edge detection sensor S2 Pickup lowering start sensor S2-1 First pickup Lowering start sensor S2-2 Two pickup lowering start sensor S3 Separation sensor S4 Target length sensor S4a Upstream side sensor S4b Downstream side sensor S4-1 First target length sensor S4-2 Second target length sensor S5 Double feed detection sensor S5- 1 Transmitter S5-2 Receiver

Patent 3618898 Japanese Patent Laid-Open No. 2005-324872

Claims (16)

A sheet material accommodating portion for accumulating and accommodating a plurality of sheet materials;
A sheet material conveyance unit for conveying the sheet material to a predetermined conveyance target position;
A sheet material is called from a plurality of sheet materials by applying a conveying force toward the sheet material conveying unit to the outermost sheet material of the plurality of sheet materials in the sheet material accommodating unit. Sheet material calling means;
The sheet material calling unit separates another sheet material that overlaps with the one sheet material to which the conveying force is applied and is directed to the sheet material conveying unit from the one sheet material, and the one sheet Separating means for directing only the material to the sheet material conveying section;
Sheet material calling control means for controlling the sheet material calling means,
When the sheet material calling unit receives the call start signal transmitted from the sheet material calling control unit, the sheet material calling unit starts a calling operation for applying a conveying force to the one sheet material, and starts the calling operation. Then, it is a configuration that requires a predetermined rise time before starting to convey the one sheet material,
After starting to apply the conveying force to the one sheet material, the application of the conveying force by the sheet material calling unit is stopped before the conveying force is applied to the next sheet material. In the sheet material conveying device to
Detecting a leading edge in the conveying direction of the sheet material conveyed at a predetermined position in the sheet material conveying section, and having a leading edge detecting means for transmitting a leading edge detection signal to the sheet material calling control means when the leading edge is detected And
The sheet material feeding control unit transmits the calling start signal to the sheet material calling unit at a predetermined timing based on the leading edge detection signal. In the sheet material conveying apparatus according to claim 1,
Sheet material length information input means for inputting sheet material length information, which is information on the length in the conveying direction of the sheet material accommodated in the sheet material accommodating portion, to the sheet material call control means;
The sheet material calling control means transmits the call start signal to the sheet material calling means based on the leading edge detection signal and the sheet material length information. In the sheet material conveying apparatus according to claim 2,
The sheet material length information input means includes sheet material length detection means for detecting the length of the sheet material accommodated in the sheet material accommodating portion in the conveyance direction. In the sheet | seat material conveying apparatus of Claim 2 or 3,
Detecting the trailing edge when the trailing edge of the sheet material conveyed in a predetermined position downstream of the separation means in the conveying direction of the separating means is detected and the trailing edge is detected. Rear end detection means for transmitting a signal to the sheet material call control means,
When the sheet material call control means determines that the length in the transport direction of the sheet material accommodated in the sheet material accommodating portion is within a predetermined range based on the sheet material length information, the tip Sending the call start signal to the sheet material calling means at a predetermined timing after receiving the detection signal;
When it is determined that the length in the conveyance direction of the sheet material accommodated in the sheet material accommodating portion is outside the predetermined range, the call start signal is transmitted at a predetermined timing after receiving the rear end detection signal. A sheet material conveying apparatus, characterized in that the sheet material is transmitted to a sheet material calling means. In the sheet material conveyance device according to any one of claims 2 to 4,
A plurality of the leading edge detection means are provided so that the leading edge in the conveyance direction of the sheet material conveyed at a plurality of positions in the sheet conveyance unit can be detected,
The sheet material call control means selects one of the plurality of leading edge detection means based on the sheet material length information,
A sheet material conveying apparatus, wherein the calling start signal is transmitted to the sheet material calling means at a predetermined timing after receiving the leading edge detection signal from the selected leading edge detection means. In the sheet material conveyance device according to any one of claims 2 to 4,
The sheet material call control means includes a storage unit that stores a plurality of pieces of information on the predetermined timing,
The sheet material call control means selects one of a plurality of predetermined timings based on the sheet material length information,
The sheet material conveying apparatus, wherein the calling start signal is transmitted to the sheet material calling means at the selected predetermined timing after receiving the leading edge detection signal. In the sheet material conveyance device according to any one of claims 1 to 6,
The sheet material calling means is driven with respect to the one sheet material by driving in contact with the outermost sheet material of the plurality of sheet materials accommodated in the sheet material accommodating portion. A sheet material calling member for applying a conveying force, and a sheet material calling member contacting / separating mechanism for bringing the sheet material calling member into contact with or separating from the sheet material in the sheet material storage unit,
When the sheet material calling means receives the call start signal, as the calling operation, the sheet material calling member contacting / separating mechanism makes the sheet material calling member come into contact with the sheet material in the sheet material accommodating portion; An operation for driving the sheet material calling member in contact with the sheet material is performed. In the sheet material conveyance device according to any one of claims 1 to 6,
The leading edge detection means detects the leading edge in the conveying direction of the sheet material conveyed at a predetermined position in the sheet material conveying portion upstream of the leading edge detection position where the leading edge detection position of the sheet material is detected, Having an upstream tip detection means for transmitting an upstream tip detection signal to the sheet material call control means when the tip is detected;
The sheet material calling means is a sheet material calling member that applies a conveying force by driving in a state in which the sheet material calling means is in contact with the outermost one sheet material of the plurality of sheet materials accommodated in the sheet material accommodating portion. And a sheet material calling member contacting / separating mechanism for bringing the sheet material calling member into contact with or separating from the sheet material in the sheet material accommodating portion,
The sheet material call control means transmits a call preparation signal for performing a preparatory operation before the call operation to the sheet material call means at a predetermined timing based on the upstream side leading edge detection signal,
When the sheet material calling means receives the call preparation signal, as the preparatory operation, the sheet material calling member contacting / separating mechanism performs an operation of bringing the sheet material calling member into contact with the sheet material in the sheet material accommodating portion. And
When the sheet material calling means receives the call start signal, the sheet material conveying device executes an operation of driving the sheet material calling member in contact with the sheet material as the calling operation. In the sheet material conveyance device according to any one of claims 1 to 8,
The sheet material calling means is a sheet material calling member that applies a conveying force by driving in a state in which the sheet material calling means is in contact with the outermost one sheet material of the plurality of sheet materials accommodated in the sheet material accommodating portion. With
When the sheet material calling means receives the call start signal, the sheet material conveying device executes an operation of driving the sheet material calling member in contact with the sheet material as the calling operation. In the sheet material conveyance device according to claim 9,
The sheet material feeding device includes a sheet material calling member contacting / separating mechanism for bringing the sheet material calling member into contact with or separating from the sheet material in the sheet material accommodating portion. In the sheet material conveying apparatus according to claim 10,
When the sheet material calling means receives the call start signal, as the calling operation, the sheet material calling member contacting / separating mechanism causes the sheet material calling member to contact the sheet material in the sheet material accommodating portion; An operation for driving the sheet material calling member in contact with the sheet material is performed. In the sheet material conveyance device according to any one of claims 1 to 11,
Detecting the trailing edge when the trailing edge of the sheet material conveyed in a predetermined position downstream in the sheet conveying direction from the region where the separating action of the separating means works is detected and this trailing edge is detected A trailing edge detecting means for transmitting a signal to the sheet material calling control means;
A double feed detection means for detecting whether or not double feed of the sheet material has occurred in the vicinity of the region where the separation action of the separation means works,
The sheet material calling control means transmits the call start signal to the sheet material calling means at a predetermined timing after receiving the trailing edge detection signal when the double feeding detecting means detects the occurrence of double feeding. The sheet | seat material conveying apparatus characterized by doing. In the sheet material conveying apparatus according to claim 12,
The multi-feed detection unit is an ultrasonic detection sensor. In the sheet material conveying apparatus according to claim 12,
The multi-feed detection unit is a light transmission type detection sensor. An original conveying means for conveying original paper as a sheet material;
An image reading apparatus comprising: a reading unit that reads a document image of a document sheet conveyed by the document conveying unit;
An image reading apparatus using the sheet material conveying apparatus according to claim 1 as the document conveying means. Image reading means;
An image forming apparatus comprising: an image forming unit that forms an image based on a document image read by the image reading unit;
An image forming apparatus comprising the image reading apparatus according to claim 15 as the image reading means.

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