JP2006264959A - Paper carrying device and image forming device having paper carrying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper carrying device and an image forming device having the paper carrying device, capable of preventing an erroneous determination of double feed detection for detecting that paper is made double feed. <P>SOLUTION: This paper carrying device 2 has paper carrying means 16 and 9 capable of carrying the paper in the reciprocal direction, double feed detecting means 80 and 80a for detecting that the paper P carried on a paper carrying passage is carried with overlapped by two or more, and a paper carrying condition setting means for setting and changing a paper carrying condition of the double feed detecting timing by the double feed detecting means 80 and 80a. The paper carrying device is characterized by determining the existence of a double feed, by confirming output of the double feed detecting means 80 and 80a, by carrying the paper P again, by changing the paper carrying condition, when a detecting result of the double feed detecting means 80 and 80a is determined as the double feed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet conveying apparatus having a multi-feed detection unit that is connected to an image forming apparatus or the like and detects a multi-feed of a conveyed sheet, and an image forming apparatus including the sheet conveying apparatus.

Conventionally, a plurality of multifeed detection sensors are known. For example, a method using a light transmission type sensor (for example, see Patent Document 1) that recognizes the transmitted light amount of the conveyed paper in advance by learning and determines double feeding based on the difference from the transmitted light amount of the actually transported paper, Similarly, using a sensor for detecting the paper thickness, a method for determining that the thickness of the conveyed paper is different from the learned value (for example, see Patent Document 2 and Patent Document 3), an ultrasonic double feed detection sensor Thus, the double feed is detected from the change in phase or attenuation (see, for example, Patent Document 4). Furthermore, when detecting double feeds in this type of double feed detection sensor, there are configurations that change the transport conditions only in the area where double feeds are detected, and those that check multiple points on the same paper to determine the presence or absence of double feeds To do. (For example, refer to Patent Document 4).
JP-A-6-9106 JP-A-5-87526 Japanese Patent Laid-Open No. 2002-243406 JP 2003-176063 A

  However, in the conventional control, the sheet conveyance speed is set to be slow or the sheet is bent to have an air layer, so that the productivity is lowered even when the sheets are not double-fed. Or damage the paper.

  Accordingly, the present invention has been made paying attention to the above problems, and an object of the present invention is to provide a sheet conveying apparatus and an image forming apparatus including the sheet conveying apparatus that solve the problems.

  In order to achieve the above object, in the sheet conveying apparatus according to claim 1, the sheet conveying means that can convey the sheet in the forward and reverse directions and two or more sheets conveyed on the sheet conveying path are conveyed in an overlapping manner. A multi-feed detecting means for detecting whether or not, and a paper transport condition setting means for setting or changing a paper transport condition at a multi-feed detection timing by the multi-feed detecting means. If it is determined, the paper transport condition is changed, the paper is transported again, the output of the double feed detection means is confirmed, and the presence or absence of double feed is determined.

  Further, in the paper transport apparatus according to claim 2, whether or not two or more paper transported on the paper transport path is transported in a position separated from the paper transport means for transporting the paper by a predetermined amount in the paper transport direction. Each paper when it passes through each double feed detecting means, and has a paper feed condition setting means for setting and changing the paper feed condition of the double feed detection timing by the double feed detecting means. It is characterized in that the conveyance conditions can be set differently.

  Furthermore, in the paper transport device according to claim 3, whether or not two or more paper transported on the paper transport path is transported in a position separated from the paper transport means for transporting the paper by a predetermined amount in the paper transport direction. A double feed detecting means for detecting whether or not and a paper transport condition setting means for setting and changing a paper transport condition at a double feed detection timing by the double feed detecting means, wherein the double feed is detected by the double feed detecting means. It is characterized in that the sheet conveyance conditions can be set differently at the time.

  Furthermore, in the paper conveying apparatus according to claim 4, the double feed detecting means is implemented by a method using ultrasonic transmission / reception.

  Furthermore, in the paper conveying apparatus according to claim 5, the double feed detecting means is implemented by a method of detecting a change in paper thickness with respect to a reference paper thickness.

  Furthermore, in the paper conveying apparatus according to claim 6, the double feed detecting means is implemented by a system that uses a transmissive optical sensor to detect a change in the transmitted light amount with respect to a reference transmitted light amount. Features.

  Furthermore, in the paper conveying apparatus according to claim 7, the paper conveying condition is a paper conveying speed, and the paper conveying speed is changed.

  Furthermore, in the paper transporting apparatus according to claim 8, the paper transporting condition is a speed difference between transport speeds of driving systems arranged upstream and downstream of the double feed detecting means, and the speed difference is changed. And

  Furthermore, in the paper transport apparatus according to claim 9, the paper transport condition is a speed difference between a transport speed of a paper front surface side roller and a paper back surface side roller of a driving system disposed upstream and downstream of the double feed detecting means. The speed difference is changed.

  Furthermore, an image forming apparatus according to a tenth aspect is characterized by including the paper conveying apparatus according to any one of the first to ninth aspects.

  According to the present invention, when a double feed is detected in a sheet to be transported, by changing the transport conditions such as the transport speed and detecting the presence / absence of the multi-feed again, in the state where the multi-feed is not clearly performed Further, the sheet can be conveyed at high speed without damaging the sheet, and erroneous determination of double feeding can be prevented.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a paper conveying device of the present invention will be described with reference to the drawings.

  FIG. 1 is a view showing a first embodiment of the present invention, and shows the arrangement of rollers for paper conveyance and double feed detection sensors. Here, an ultrasonic sensor is illustrated as a double feed detection sensor.

  In FIG. 1, the separation conveyance roller 8 is rotated clockwise by a driving source 81 and conveys the paper in the left direction. The separation belt 6 is rotated in the same direction as the separation conveyance roller 8 by the same driving source 81 as the separation conveyance roller 8 and prevents the paper P from being double-fed. The paper P separated and transported by the separation transport roller 8 and the separation belt 6 is transported to the second transport roller 9 by the first transport roller 16 and its driven roller 82, and further by the second transport roller 9 and its driven roller 83. Transport in the direction. The first conveyance roller 16 and the second conveyance roller 9 are driven by a separation motor 100 and a conveyance motor 101, which are driving sources, respectively, and rotate in both forward and reverse directions, thereby causing the paper P to move toward the first conveyance roller 16. It can also be moved.

  Further, a double feed detection sensor 80 is disposed between the first conveyance roller 16 and the second conveyance roller 9 so as to face the paper conveyance path, and transmits ultrasonic waves to the paper P and faces the paper P with the paper P interposed therebetween. The receiving side detects whether the separated paper is not double-fed by using the phase and / or attenuation data.

  The speeds of the first transport roller 16 and the second transport roller 9 are respectively controlled by a control circuit (not shown). Normally, unless double feed is detected, the paper P is printed at the same speed with emphasis on damage to the paper and productivity. Transport. When double feeding is detected, the paper P is reversely conveyed and conveyed again. At this time, the second conveying roller 9 is controlled later than the first conveying roller 16 to bend the sheet, so that an air layer is easily formed between the sheets. Further, the second transport roller 9 is stopped and the sheet P is bent more by transport only by the first transport roller 16, so that an air layer can be formed more effectively, and it is possible to easily determine the double feed. Based on this result, the presence / absence of double feeding is determined.

  By this series of controls, it is possible to detect double feed twice for the same paper, and it is possible to vary the transport conditions of the paper P for each double feed detection operation.

  The same effect can be obtained by detecting the double feed by stopping the paper P when the double feed is detected, transporting the paper P in the reverse direction, changing the transport condition again from the point where the double feed is detected, and restarting the paper transport. Is obtained.

  In this description, the drive sources of the first transport roller 16 and the second transport roller 9 are configured separately, but may be a common drive source as long as they are controlled at the same speed. The same control is possible even if a drive transmission mechanism such as a clutch is interposed in the same drive source configuration.

  In particular, as in the double feed detection sensor according to Patent Document 4, in a configuration in which multiple feeds are sampled from a plurality of points and the double feed detection count exceeds a predetermined threshold value, it is determined that double feed is performed one or more times. By changing the transport conditions when a predetermined number of times are detected and further increasing the accuracy of double feed detection thereafter, the double feed determination operation is continued without transporting the paper P in the reverse direction and reconfirming the double feed detection point. Is possible. Further, by increasing the weighting of the double feed determination after the change of the transport condition, it is possible to make a determination with higher accuracy.

  In the above configuration, the paper separation mechanism is included as a means for mechanically preventing the double feeding of the paper P. However, the separation mechanism is not essential for the contents of the present invention.

  FIG. 2 is a view showing a second embodiment of the present invention, in which a plurality of the ultrasonic multifeed detection sensors are arranged.

  In FIG. 2, the separation conveyance roller 8, the separation belt 6, and the drive source 81 have the same configuration as that in FIG. 1. The sheet P separated and conveyed by the separation and conveyance roller 8 and the separation belt 6 includes the first conveyance roller 16 and its driven roller 82, the first conveyance roller 16 and the second conveyance roller 9, and its driven roller 83, and further The sheet P is conveyed in the direction of the third conveyance roller by the three conveyance rollers 16a and the driven roller 82a. The first transport roller 16 and the second transport roller 9 are driven so that the paper P is transported at a constant speed, and a double feed detection sensor 80 is disposed between them, and whether or not the separated paper is being double fed. Is detected.

  A double feed detection sensor 80a is disposed between the second conveyance roller 9 and the third conveyance roller 16a, and if double feed is not detected by the double feed detection sensor 80, the first, second, and third conveyances are performed. The rollers 16, 9, and 16a are controlled at a constant speed, and the paper P is transported under conditions optimal for paper transport including damage to the paper P and productivity. When double feed is detected, a speed difference is provided between the second transport roller 9 and the third transport roller 16a in the same manner as the double feed determination in FIG. 1, and the first and second transport rollers 16, 9 are provided. Is set to be different from the conveyance condition of the sheet conveyed, and the presence / absence of double feeding is confirmed again to confirm double feeding.

  FIG. 3 is a view showing a third embodiment of the present invention, in which the driven rollers 82 and 83 of the first and second transport rollers 16 and 9 are driven by separate driving sources.

  In FIG. 3, the separation conveyance roller 8, the separation belt 6, and the drive source 81 have the same configuration as that in FIG. 1. The sheet separated and conveyed by the separation conveyance roller 8 and the separation belt 6 includes a first conveyance roller 16 driven by a separation motor 100 as a driving source, and a counter roller 82 driven by a driven roller motor 110 as a driving source. Further, the sheet is conveyed in the direction of the second conveying roller by the second conveying roller 9 driven by the conveying motor 101 which is a driving source and the opposing roller 83 which is driven by the driven roller motor 110 which is the same driving source as the opposing roller 82. To do. Normally, the first transport roller 16 and its counter roller 82, and the second transport roller 9 and its counter roller 83 are each driven so that the sheet is transported at a constant speed. Similar to FIG. 1, a double feed detection sensor 80 is disposed between the first conveyance roller 16 and the second conveyance roller 9 to detect whether or not the separated paper is being double-fed.

  When double feed is not detected by the double feed detection sensor 80, the first and second transport rollers 16, 9 and the opposing rollers 82, 83 are controlled at a constant speed while passing through the double feed detection sensor 80. Then, the paper P is transported under the optimum conditions for paper transport including damage to the document and productivity.

  When double feeding is detected, the paper P is transported backward in the direction of the first transport roller and transported again. The paper transport conditions at this time are as follows: the transport speed of each of the opposing rollers 82 and 83 is lower than the transport speed of the first and second transport rollers 16 and 9, or is transported while being stopped. The upper sheet P is further bent to form an air layer between the sheets, thereby ensuring the determination of double feeding. Based on this result, the presence / absence of double feeding is determined.

  Similarly to the above-described embodiment, it is also possible to change the transport conditions when a predetermined number of times of double feeding is detected.

  The paper transport conditions in each configuration have been described above as an example, but various conditions may be considered depending on the configuration of the apparatus, and the present invention is not limited to the transport conditions. The same applies to each double feed detection method described later.

  In the above-described embodiment, an ultrasonic sensor is used as the double feed detection sensor 80. However, it is also possible to detect double feed by detecting a change in sheet thickness with the configuration shown in FIGS. It is. In the case of detecting double feed by changing the paper thickness, the thickness of the paper to be conveyed is preliminarily set for one sheet in the case of the same paper, or for all the sheets in the case of a plurality of types of paper such as originals. It is necessary to recognize the thickness.

  FIG. 8 shows a method of detecting the paper thickness using a magnetic field sensor. The paper thickness is determined from the output value corresponding to the distance between the movable iron core and the magnetic field sensor facing each other with the paper P interposed therebetween. Details are described in Patent Document 3 and are omitted here.

  FIG. 9 uses a distance measuring sensor using a PSD element and detects the sheet thickness based on the displacement amount of the roller in contact with the conveyed sheet P. Details of the sensor are well known in Patent Document 2, and are omitted here.

  In the double feed detection sensor 80 configured to detect the sheet thickness, it is desirable to set the conveyance conditions to be different from those of the ultrasonic double feed detection sensor.

  In the configuration of FIG. 1, unless double feed is detected, the first transport roller 16 and the second transport roller 9 are set at a constant speed and high speed in consideration of damage to the paper and productivity. The sheet P is conveyed under various conditions. When double feeding is detected, the paper P is transported backward in the direction of the first transport roller and transported again. The paper conveyance conditions at this time are such that the first conveyance roller 16 is controlled later than the second conveyance roller 9 to convey the paper P in the pulling direction, thereby bringing the paper P into close contact. This makes it possible to stabilize the sheet thickness and increase the detection accuracy. Alternatively, the sheet P is bent by causing the second conveying roller 9 to be slower than the first conveying roller 16 or stopped so that an air layer is easily formed between the sheets, thereby increasing the thickness and making it easier to determine double feeding. it can. Based on this result, the presence / absence of double feeding is determined.

  Similar conveyance conditions may be set in the configuration of FIG.

  In the configuration of FIG. 3 as well, in the same way as the ultrasonic type, the conveying speed of each of the opposing rollers 82 and 83 is lowered or stopped with respect to the conveying speed of the first and second conveying rollers 16 and 9. Thus, the upper sheet P at the time of double feeding is further bent to form an air layer between the sheets, thereby making it possible to reliably determine the double feeding.

  A multi-feed detection sensor 80 using a transmission type optical sensor is described in Patent Document 1, but various transport conditions can be set for the multi-feed detection of this method. Also in the transmission type optical sensor, it is necessary to recognize in advance the amount of light transmitted through the paper P to be transported when the same paper is used, and when the paper P is composed of a plurality of types of paper P such as a document. There is.

  In the configuration of FIG. 1, unless double feed is detected, the first conveyance roller 16 and the second conveyance roller 9 are set at a constant speed and at a high speed in consideration of damage to the paper P and productivity. The paper P is conveyed under optimum conditions. When double feeding is detected, the paper P is transported backward in the direction of the first transport roller and transported again. The paper conveyance conditions at this time are such that the first conveyance roller 16 is controlled later than the second conveyance roller 9 to convey the paper P in the pulling direction, the paper P is brought into close contact, and the detection accuracy can be increased. Alternatively, the sheet P is bent by causing the second conveying roller 9 to be slower than the first conveying roller 16 or stopped so that an air layer is easily formed between the sheets. Easy to judge. Based on this result, the presence / absence of double feeding is determined.

  Similar conveyance conditions may be set in the configuration of FIG.

  Similarly, in the configuration of FIG. 3, the conveying speed of each of the opposing rollers 82 and 83 is lower than that of the conveying speed of the first and second conveying rollers 16 and 9, or the conveying speed is stopped to perform the double feeding. The sheet P on the upper side of the sheet is further bent to form an air layer between the sheets, thereby making it possible to reliably determine the double feed.

  The paper conveying apparatus according to the present invention has been described above. However, as an example, the case where the paper conveying apparatus is applied to an original conveying apparatus connected to an image forming apparatus will be described. In addition to the document transport device, this paper transport device has a paper transport function, such as an image forming device paper feed unit, and a paper discharge processing device that performs post-processing on paper ejected from the image forming device. Needless to say, the present invention can be applied to the obtained transport system.

  FIG. 4 is a diagram illustrating the configuration of the image forming apparatus. The image forming apparatus includes an image forming apparatus main body including an image reader 200 and a printer unit 300, a folding device 500, and a finisher 600. On the upper part of the image reader 200, the document conveying device 2 is mounted.

  The document conveying device 2 feeds the documents P set on the document tray 4 one by one from the first page in order, and conveys them to the document table glass 205 through a curved path. A method of reading a document includes a fixed reading mode in which a document is read by conveying and stopping the trailing end of the document to a reading start position on the platen glass 205 and moving the scanner unit 206 from left to right, Is fed to the second reading position at the reading speed, and there is a flow reading mode in which the original is read while the scanner unit 206 is fixed at the second reading position. Thereafter, the read original is discharged to the paper discharge tray 10.

  An image of a document read by the image sensor 208 via the lens 207 is subjected to image processing, stored in a hard disk (not shown), and sent to the exposure control unit 305 via the printer control unit. The exposure control unit 305 outputs laser light corresponding to the image signal. When this laser light is irradiated onto the photosensitive drum 306, an electrostatic latent image is formed on the photosensitive drum 306. The electrostatic latent image on the photosensitive drum 306 is developed by the developing unit 307, and the developer on the photosensitive drum 306 is applied to the sheet fed from any of the cassettes 308 and 309, the manual sheet feeding unit 310, and the duplex conveyance path 311. Transferred by the transfer unit 312.

  When the developer-transferred sheet is guided to the fixing unit 313, the developer is fixed. The sheet that has passed through the fixing unit 313 is once guided from the path 315 to the path 314 by a flapper (not shown), and after the trailing end of the sheet has passed through the path 315, the sheet is switched back and guided from the path 316 to the discharge roller 317. . As a result, the surface onto which the developer has been transferred can be turned downward (face down) and discharged from the printer unit 300 by the discharge roller 317.

  In this way, by discharging face down, it is possible to form an image in the correct page order from the first page even when using the document feeder 2 or when printing an image output from an external computer. It is.

  The sheet discharged from the discharge roller 317 is sent to the folding device 500. The folding device 500 performs a process of folding the sheet into Z-folds. When the folding process is specified for the A3 size sheet or the B4 size sheet, the folding apparatus 500 performs the folding process, and then the sheet is sent to the finisher 600. The other size sheets are sent to the finisher 600 as they are. The finisher 600 performs bookbinding processing, binding processing, punching processing, and the like. In addition, an inserter 700 is provided on the upper portion of the finisher 600 and feeds a cover sheet, a slip sheet, and the like to the finisher 600.

  FIG. 5 is a detailed view of the document conveying device 2 to which the present invention is applied. Only the main part is shown together with FIG. A document tray 4 is provided above, and a wide belt 7 wound around a driving roller 38 and another turn roller 37 is disposed below the document tray 4, and sheet documents P placed on the document tray are sequentially placed on the uppermost sheet. And is conveyed to the platen glass 205 of the image reading apparatus 200.

  The wide belt 7 is in contact with the original platen glass 205, and the sheet original P conveyed from the original tray 4 is placed at a predetermined position on the original platen glass 205, or the sheet on the original platen glass 205 is placed. The original P is carried out onto the paper discharge tray 10.

  The ADF according to this configuration is well known, and a detailed description of its operation is omitted. Here, the arrangement and detection operation of the double feed detection sensor will be described in detail with reference to a sheet document feeding operation (see FIGS. 5 and 6). 5 and 6, (A), (B), (C), (D), (E), (F), (G), (C), (L), (N), (L) Is a transport path.

  In the document feeder 2, the swing motor 103 is driven to lower the sheet feed roller 5 from the position indicated by the solid line in FIG. 6 where the sheet feed roller home sensor 45 is on onto the document bundle placed on the document tray. To do. After confirming that the paper feed roller 5 has been lowered by turning off the paper feed roller home sensor 45, the paper feed roller 5 is placed on the paper surface placed on the document tray 4 by turning on the swing position sensor 46. When the movement is detected, the driving of the swing motor 103 is stopped.

  The separation motor 100 is turned on, and the sheet roller 5, the separation belt 6, the separation conveyance roller 8, and the first conveyance roller 16 falling on the document bundle P are rotated, respectively, so that the uppermost sheet document of the document bundle P is rotated. Is separated and conveyed through the sheet document feed path (A). At this time, the document conveying speed is set to reduce the time between the document scanning and the printing operation for the first sheet document, and to reduce the paper gap with the preceding document for the second and subsequent sheet documents. It is transported at high speed to improve performance. After that, when the leading edge of the sheet document is detected by turning on the separation sensor 30, the document is conveyed for a predetermined time, and when the sheet is nipped by the first conveyance roller 16, the sheet feeding roller is raised.

  When the sheet is further conveyed by a predetermined amount, the leading edge of the sheet document reaches the double feed detection sensor 80 disposed between the first conveyance roller 16 and the second conveyance roller 9. At this point, it is determined whether or not the sheet document being conveyed has been double-fed due to poor separation, but in general, the output of the sensor is unstable at the end of the paper. Double feed detection is started from the point of time. The detection of the arrival of the leading edge of the sheet document at the double feed detection sensor 80 can be determined by a change in the level of the double feed detection sensor in any double feed detection method other than the above method.

  Thereafter, with the second conveyance roller 9 stopped, a leading edge of the sheet original is abutted against the second conveyance roller 9 to form a loop, and this is corrected even when skew occurs during separation.

  The reverse sheet feeding flapper 22 is switched to the position shown by the chain line in FIG. 6 by turning on the path switching solenoid 107, nipped by the first conveying roller 16, and the sheet document in a state where the leading edge is abutted against the second conveying roller 9. , The separation motor 100, the conveyance motor 101, and the belt motor 102 are turned on so that the first conveyance roller 16 and the second conveyance roller are turned on. 9. Drive the wide belt 7.

  Then, the registration sensor 39 detects the leading edge of the sheet document to confirm that the sheet document has been conveyed to the sheet document feeding path (c). When a predetermined amount is conveyed from the registration sensor 39, a double feed detection sensor 80a according to a second embodiment, which will be described later, is disposed, and the passage of the leading edge and the trailing edge of the sheet document to the double feed detection sensor is detected by double feed detection. The determination is made in the same manner as the sensor 80, and the double feed detection is similarly processed.

  Thereafter, when it is detected that the trailing edge of the sheet document has passed the separation sensor 30, when the clock signal input from the separation clock sensor 100b is counted by the distance from the first conveying roller 16 to the separation sensor 30, the sheet document is Since the rear end is missing from the first conveying roller 16, the separation motor 100 is turned off to stop the driving of the first conveying roller 16.

  Further, by conveying the sheet document by a predetermined amount, the double feed detection is terminated when the trailing edge of the sheet document passes through the double feed detection sensor. Similar to the detection of the leading edge of the sheet document, it is possible to detect the trailing edge by changing the level of the double feed detection sensor, and in order to avoid an unstable area of the sensor output level, a predetermined amount before the trailing edge of the sheet document. End double feed detection.

  Thereafter, when the paper feed sensor 35 detects that the trailing edge of the sheet document has passed, the belt excitation clock is counted so as to stop the sheet document at a predetermined position on the platen. Thereafter, when the distance corresponding to the distance from the paper feed sensor 35 to the second conveyance roller 9 is counted, the conveyance motor 101 is turned off. When the count is completed and the predetermined position is reached, the belt motor 102 and the path switching are performed. The solenoid 107 is turned off.

  Here, although the drive sources 100 and 81 have been described as separate drive sources in the paper conveying apparatus in FIG. 1, they are configured as the same drive source by using a clutch (CL), and this separation motor 100 can be rotated forward and backward. The first conveyance roller 16 of the separation unit is driven, the separation conveyance roller 8 and the separation belt 6 are driven via the separation clutch 106, and the drive is transmitted to the paper feed roller 5. By turning off the separation clutch 106, it is possible to reverse the first conveying roller 16 independently.

  FIG. 7 is a drive system diagram showing motors and solenoids for driving the respective transport rollers and flappers, which communicate with the operation unit 49, the printer unit 300, and the image reader 200. The IC 502 and each drive system include a driver and the like. And connected to an output port of the CPU 501 or a control circuit to control its operation.

  Specifically, a double feed detection sensor 1 (80), a double feed detection sensor 2 (80a), a separation clock sensor 100b, a paper discharge clock sensor 104b, a separation sensor 30, a reverse detection sensor 33, a manual registration sensor 34, a paper feed Sensor 35, reverse sensor 3, manual document detection sensor 60, registration sensor 39, document set detection sensor 40, document trailing edge detection sensor 41, final document detection sensor 43, paper width detection sensor 44, paper feed roller home sensor 45, swing Position sensor 46, length detection sensor 48, driven roller motor 110, separation motor 100, transport motor 101, belt motor 102, swing motor 103, paper discharge motor 104, stopper solenoid 105, separation clutch 106, path switching solenoid 107, reverse flapper solenoid 108, paper discharge flapper solenoid 109, city is controlled by the CPU 501, and the separation motor 100 by the controller 503a, the discharge motor 104 is connected to the controller 507a.

  Further, various sensors such as the double feed detection sensor 80 and the double feed detection sensor 80a are connected to the input port of the CPU 501, and are used to monitor the behavior of the sheet original and the behavior of the movable load in the apparatus. .

  Next, processing when double feeding is detected will be described with reference to FIGS.

  FIG. 10 shows a process based on the first embodiment, where the sheet document feeding / separating operation is started (step S601), and the sheet document is conveyed according to the normal high-speed conveyance setting (steps S602 and S603). When the conveyed sheet document reaches the double feed detection sensor 80, double feed detection is started (step S604). If double feed is detected, the first and second transport rollers are stopped and reversed ( In step S605), the sheet document is reversely conveyed. Then, the sheet document conveyance speed is set to be lower than the set conveyance speed (step S606), the first and second conveyance rollers are driven to rotate forward (step S607), and the sheet document is conveyed again. Under this transport condition, double feed is detected (step S608). If double feeding is detected again in step S608, the conveyance of the sheet original is stopped, a display indicating that double feeding is being performed, and the process ends (step S609). If double feeding is not detected in step S604 or S608, the conveyance of the sheet document onto the document table glass is completed (step S610), and the process ends.

  FIG. 11 shows a process based on the second embodiment. The sheet document feeding / separating operation is started (step S611), and the sheet document is conveyed by the normal high-speed conveyance setting (steps S612 and S613). When the conveyed sheet document reaches the double feed detection sensor 80, double feed detection is started (step S614). If double feed is detected, the sheet document conveyance speed is set from the set conveyance speed. Is also set to a low speed (step S615). The first and second transport rollers continue to rotate forward (step S616), and transport the sheet document in the direction of the double feed detection sensor 80a disposed after the second transport roller. The double feed detection sensor 80a detects double feed under the changed transport conditions (step S617), and when double feed is detected again, the conveyance of the sheet document is stopped and the double feed is detected. Display is performed and the process ends (step S618). If double feeding is not detected in step S614 or S617, the conveyance of the sheet document onto the document table glass is completed (step S619), and the process is terminated.

  FIG. 12 shows a process based on the third embodiment, in which the sheet document feeding / separating operation is started (step S621), and the first and second transport rollers and each driven roller are at a constant speed and normal high-speed transport. The sheet original is conveyed according to the setting (steps S622 and S623). When the conveyed sheet document reaches the double feed detection sensor 80, double feed detection is started (step S624). When double feed is detected, the first and second transport rollers and each driven roller are turned on. Stop and reverse (step S625), the sheet document is transported in reverse. Then, the conveyance speed on the side of each driven roller is set to be lower than that of the first and second conveyance rollers (step S626), and the first and second conveyance rollers and each driven roller are driven to rotate forward (step S626). (S627) The sheet original is conveyed again, and double feeding is detected under this conveyance condition (step S628). If double feeding is detected again in step S628, the conveyance of the sheet document is stopped, a display indicating that double feeding is being performed, and the process ends (step S629). If double feeding is not detected in step S624 or S628, the conveyance of the sheet document onto the document table glass is completed (step S630), and the process ends. The setting speed of the driven roller in step S626 is not a problem as long as it does not affect the conveyance of the sheet document even in the stopped state.

FIG. 3 is a diagram illustrating a configuration of a double feed detection unit of the paper transport apparatus according to the first embodiment of the present invention. It is a figure which shows the structure of the double feed detection part of the paper conveying apparatus by 2nd Example based on this invention. It is a figure which shows the structure of the double feed detection part of the paper conveying apparatus by 3rd Example based on this invention. 1 is a diagram illustrating an overall configuration of an image forming apparatus according to the present invention. It is sectional drawing which shows the structure of the document conveying apparatus to which the double feed detection part by this invention is applied. FIG. 6 is an enlarged view of a conveyance unit of the document conveyance device in FIG. 5. It is a block diagram which shows the outline of the control system of the original conveying apparatus to which the double feed detection part by this invention is applied. It is an enlarged explanatory view showing a first embodiment of a double feed detection unit using a thickness detection sensor. It is expansion explanatory drawing which shows the 2nd Example of the double feed detection part using another thickness detection sensor. 6 is a flowchart for explaining double feed detection processing according to a first embodiment applied to a document conveying apparatus. 10 is a flowchart for describing double feed detection processing according to a second embodiment applied to a document conveying apparatus. 10 is a flowchart for explaining double feed detection processing according to a third embodiment applied to the document conveying apparatus.

Explanation of symbols

P paper (sheet original)
(A), (B), (C), (D), (E), (F), (G), (H), (R), (N), (L) Transport path 2 Document transport device 3 Reverse sensor 4 Document tray 5 Paper feed roller 6 Separation belt 8 Separation conveyance roller 9 Second conveyance roller 16 First conveyance roller 30 Separation sensor 39 Registration sensor 80 Double feed detection sensor (corresponding to double feed detection means)
80a Double feed detection sensor (corresponding to double feed detection means)
81 Drive source (separated)
82 Followed roller (opposing roller) (opposite the first conveying roller)
83 Followed roller (opposite roller) (opposite the second transport roller)
DESCRIPTION OF SYMBOLS 100 Separation motor 101 Conveyance motor 102 Belt motor 106 Separation clutch 110 Driven roller motor 200 Image reader 205 Original plate glass 300 Printer unit 500 Folding device 501 CPU
600 Finisher 700 Inserter

Claims (10)

A paper transport means for transporting paper in the forward and reverse directions;
A double feed detection means for detecting whether or not two or more sheets conveyed on the sheet conveyance path are conveyed in an overlapping manner;
In a paper transport apparatus having a paper transport condition setting means for setting and changing a paper transport condition at a double feed detection timing by the multi-feed detection means,
When the detection result of the double feed detection means is determined to be double feed, the paper transport conditions are changed, the paper is transported again, the output of the double feed detection means is confirmed, and the presence of double feed is determined. A paper conveying device characterized by the above. Paper transport means for transporting paper,
A double feed detection means for detecting whether or not two or more sheets conveyed on the sheet conveyance path are conveyed at a position separated by a predetermined amount in the sheet conveyance direction;
In a paper transport apparatus having a paper transport condition setting means for setting and changing a paper transport condition at a double feed detection timing by the multi-feed detection means,
A sheet conveying apparatus characterized in that each sheet conveying condition when passing through each double feed detecting means can be set differently. Paper transport means for transporting paper,
A double feed detection means for detecting whether or not two or more sheets conveyed on the sheet conveyance path are conveyed at a position separated by a predetermined amount in the sheet conveyance direction;
In a paper transport apparatus having a paper transport condition setting means for setting and changing a paper transport condition at a double feed detection timing by the multi-feed detection means,
A sheet conveying apparatus characterized in that the sheet conveying condition can be set differently when the double feeding is detected by the double feeding detecting means.   4. A sheet conveying apparatus according to claim 1, wherein the multifeed detecting means is a sensor using ultrasonic transmission / reception.   4. A paper transport apparatus according to claim 1, wherein the multi-feed detection means is a sensor that detects a change in paper thickness with respect to a reference paper thickness and determines multi-feed.   The double feed detecting means according to any one of claims 1 to 3, wherein a transmission type optical sensor is used, and a change in the transmitted light amount is detected with respect to a reference transmitted light amount, thereby determining double feed. Paper transport device.   7. The paper transport apparatus according to claim 1, wherein the paper transport condition is a paper transport speed, and the paper transport speed is changed.   7. The paper transport apparatus according to claim 1, wherein the paper transport condition is a speed difference between transport speeds of driving systems disposed upstream and downstream of the double feed detection unit, and the speed difference is changed. A sheet conveying apparatus characterized by the above.   7. The paper transport apparatus according to claim 1, wherein the paper transport condition is a speed of a transport speed of a paper front side roller and a paper back side roller of a driving system disposed upstream and downstream of the double feed detecting unit. A sheet conveying apparatus characterized in that the difference in speed is changed.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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