JP4675817B2 - Automatic paper conveyance device, image reading device, and image forming device - Google Patents

Description

  The present invention relates to an automatic paper conveyance device, an image reading device, and an image forming device. For example, an image reading device such as a copying machine, a facsimile device, a scanner device, and a multifunction device, or a copying machine, a facsimile device, a printer device, and a multifunction device. The present invention relates to an automatic sheet conveying apparatus, an image reading apparatus, and an image forming apparatus that are provided in the image forming apparatus and separate the uppermost sheet from a sheet bundle and convey it to a processing position.

  2. Description of the Related Art Generally, an automatic document feeder (hereinafter simply referred to as ADF) provided in an image reading apparatus such as a copying machine or a facsimile machine, an image forming apparatus, or an image forming apparatus such as a printer is stacked on a document placing table. As a means for transporting the original document located on the upper part from the original bundle to the separation position, the raising and lowering operation of the calling roller is used.

When the document is transported, the calling roller is lowered and brought into contact with the document bundle to rotate the calling roller, thereby feeding the document located above the document bundle, the document feeding belt, the reverse roller, etc. The separating / feeding means comprising the above separates the uppermost document from the upper document and conveys it to the reading position (see, for example, Patent Document 1).
JP 2000-261625 A

  However, in the conventional ADF, the lowering operation of the calling roller is performed at a constant speed without depending on the thickness of the original bundle, so that an excessive impact is generated when the calling roller is brought into contact. The load fluctuation of the calling roller occurs and noise is generated at the time of collision. In addition to this, problems such as damaging the original and adversely affecting the durability of the calling roller have occurred.

  In addition, it is conceivable to control the lowering operation of the calling roller depending on the thickness of the original bundle. In this case, a dedicated sensor for detecting the thickness of the original bundle placed on the original placement table. It becomes necessary, and the problem that the manufacturing cost of ADF increases will occur.

  The present invention has been made to solve such a problem, and it is unnecessary to provide a dedicated sensor for detecting the paper thickness, and an excessive impact is generated when the calling means comes into contact with the sheet bundle. It is possible to provide a low-cost automatic sheet conveying apparatus, image reading apparatus, and image forming apparatus that can prevent the noise and can prevent noise and protect the calling means and the sheet bundle.

  The automatic paper conveyance device according to the present invention is moved up and down between a paper placement table on which a paper bundle is placed, and a position that abuts against the paper bundle placed on the paper placement table and a position that retreats from the paper bundle. Calling means that is freely provided and feeds the upper sheet of the sheet bundle when it comes into contact with the sheet bundle, and separates the uppermost sheet from the upper sheet bundle fed by the calling means In the automatic paper conveying apparatus, comprising: a separating / feeding means for conveying toward the processing position; and a paper size detecting means for detecting a length in the conveying direction of the sheet bundle placed on the paper placing table. The paper size detecting means comprises a sensor for detecting the thickness of the paper bundle placed on the paper placement table, and the calling means is based on the thickness information of the paper bundle detected by the paper size detecting means. Descending state for performing descent control And a one having a control means.

  With this configuration, the sheet size detecting means for detecting the length in the transport direction of the sheet bundle placed on the sheet placing table is constituted by a sensor for detecting the thickness of the sheet bundle placed on the sheet placing table. Since the lowering control of the calling unit is performed based on the thickness information of the sheet bundle detected by the sheet size detecting unit, it is unnecessary to provide a dedicated sensor for detecting the sheet thickness, and the calling unit does not need to provide a sheet bundle. It is possible to prevent an excessive shock from being generated when it comes into contact. For this reason, it is possible to prevent the generation of noise, protect the calling means and the sheet bundle, and obtain a low-cost automatic sheet conveying apparatus.

  The automatic paper conveying apparatus of the present invention comprises an alarm means for issuing an alarm when the thickness of the sheet bundle detected by the paper size detecting means is equal to or greater than the allowable number of stackable sheets. ing.

  According to this configuration, an alarm can be generated to prompt the user to stop the conveyance of the sheet when the sheet is thicker than the allowable number of stacked sheets, so that the automatic sheet conveying apparatus can be protected.

Specifically, in the automatic paper transport device, the allowable number of sheets is set, but in reality, it is possible to place more than the allowable number of sheets from the viewpoint of user operability. If a large number of sheets are transported by loading more sheets than the allowable number of sheets on the paper, there will be problems with separation / feeding, or continuous operation exceeding the allowable number of sheets will be performed automatically. There is a risk of problems such as device durability and temperature rise.
Therefore, when the sheet is thicker than the allowable number of sheets, an alarm is generated to prompt the user to stop the sheet conveyance, thereby protecting the automatic sheet conveying apparatus.

Further, the calling means of the automatic paper conveying apparatus of the present invention includes a rotating member that can be brought into contact with and retracted from the sheet bundle, and an elevating member that elevates and lowers the rotating member, and the elevating member has a stepping motor. It is composed of
With this configuration, since the lowering operation of the calling means is performed by the stepping motor, it is possible to perform highly accurate speed control by pulse counting.

  Further, in the automatic paper conveying apparatus according to the present invention, when the calling unit is controlled to be lowered by the lowered state control unit, the number of pulses of the stepping motor until the calling unit is lowered from the retracted position to the contact position. P, the number of pulses of the stepping motor for accelerating the calling means to the maximum speed is P1, and the stepping motor for reducing the calling means from the steady state at the maximum speed to the contact position. When the number of pulses is P2, the relation of P> P1 + P2 is established.

  With this configuration, by adjusting P1 and P2 to obtain the optimum steady state, the calling means can be always lowered at a constant speed, and load fluctuation occurs due to the sudden lowering of the calling means. Therefore, it is possible to further prevent an excessive shock from being generated when the calling means comes into contact with the sheet bundle.

  In the automatic paper conveyance device of the present invention, the thickness of the paper bundle placed on the paper placement table and the topmost paper are separated from the paper bundle based on the detection information of the paper size detection means. By comparing the thickness of the immediately following sheet bundle, it is configured to include separation sheet thickness calculation means for calculating the thickness of each separated sheet.

  With this configuration, the paper size detection and the paper thickness detection can be performed by the same paper size detection means, and the thickness of the paper bundle placed on the paper placement table and the thickness of the separated paper are the same. It can be detected by the paper size detecting means, and it is possible to further prevent the manufacturing cost of the paper transporting apparatus from being increased by eliminating the need for many detecting means.

  In addition, the automatic paper conveying apparatus of the present invention includes a pair of rotating members provided on the downstream side in the paper conveying direction with respect to the separating / feeding unit, and the leading edge of the separated paper abuts against the nip portion. The first skew correction unit includes a first skew correction unit, and the abutting amount is changed according to the thickness of the separation sheet.

The reason for this will be described.
The abutting operation when the abutting amount against the skew correction means is uniformly controlled regardless of the paper thickness is for the purpose of preventing paper non-feed by the rotating member and correcting the skew. If the paper is damaged or the amount of bumping is small, the paper is not fed and skew occurs.

  In general, thick paper tends to have a large slip, so if the amount of bumping is made uniform, the amount of bumping varies depending on the paper thickness, and the skew amount changes. May occur. In addition, if a dedicated sensor for detecting the paper thickness of the separation paper is provided in order to eliminate such problems, a large number of sensors are required to detect the thickness of the paper bundle and separation paper, and automatic paper conveyance The manufacturing cost of the device increases.

  Therefore, by comparing the thickness of the paper bundle placed on the paper placement table based on the detection information of the paper size detection means and the thickness of the paper bundle immediately after the uppermost paper is separated from the paper bundle, The thickness of each separated sheet is calculated, and the amount of abutment by the first skew correction unit is changed according to the sheet thickness of the separated sheet, so that the optimum skew correction is performed according to the thickness of the separated sheet. In addition, it is possible to prevent the occurrence of paper non-feed.

  In the automatic paper conveyance device of the present invention, a plurality of the paper size detection means are provided so as to be separated along the paper conveyance direction, and are provided downstream of the paper placement table in the paper conveyance direction. A stopper member having a leading end of the sheet bundle by contacting the leading end of the sheet bundle, and a separating sheet detecting unit provided between the stopper member and the first skew correcting unit and detecting the separating sheet. The relationship between the separation distance S between the separation sheet detection means and the stopper member and the separation distance Sn between the sheet size detection means is S> Sn.

  With this configuration, since the separation distance S between the separation sheet detection unit and the stopper member is larger than the separation distance Sn of each sheet size detection unit, the trailing edge of the sheet is reached before the leading edge of the sheet reaches the separation sheet detection unit. Always passes one of the paper size detecting means.

  Therefore, the paper size detecting means reliably detects the thickness of the paper bundle placed on the paper placement table and the thickness of the paper bundle immediately after the uppermost paper is separated from the paper bundle, and compares the two. be able to.

  Further, the automatic paper conveyance device of the present invention is provided on the downstream side in the paper conveyance direction with respect to the first skew correction unit and on the upstream side in the paper conveyance direction with respect to the processing position, and the processing position And a second skew correction unit having a pair of rotating members that are abutted against the leading edge of the separation sheet immediately before being conveyed to the sheet, and the second skew correction unit abuts according to the paper thickness of the separation sheet Consists of things whose amount changes.

  With this configuration, it is possible to perform an optimal skew correction according to the thickness of the separation sheet immediately before a processing position such as a reading position for reading an image on a sheet or a transfer position for transferring an image to the sheet, and to prevent unfeeding of the sheet. It can be prevented from occurring.

  The automatic paper transport device according to the present invention includes a paper discharge tray that discharges the paper that is unloaded from the processing position, and a paper discharge that is discharged to the paper discharge tray according to the thickness of the separation paper. It has a paper discharge speed varying means for varying the speed.

  With this configuration, it is possible to improve the stackability of the paper discharged to the paper discharge tray. Specifically, when paper is discharged to a paper discharge tray at a constant speed regardless of the paper thickness, thin paper that is stiff depending on the discharge speed, such as a frame on the paper transport path It may not be able to be completely discharged due to being caught in the water.

  If the discharge speed is increased as a countermeasure against this, a new problem that a large size sheet such as A3 falls from the discharge tray may occur. Therefore, even if a paper discharge speed that can fit well in the paper output tray can be set for both large and thin paper, even if thin paper with different paper thickness is stacked in the paper output tray, the stackability is extremely high. The problem of getting worse will occur.

  Accordingly, the present invention varies the paper discharge speed of the paper discharged to the paper discharge tray according to the paper thickness of the separation paper, so that the trailing edge of the thin paper that is weak is caught on the frame or the like of the paper transport path. It is possible to prevent a large-size sheet such as A3 from dropping from the sheet discharge tray and to stack sheets of different thicknesses on the sheet discharge tray.

In addition, the automatic paper conveyance device of the present invention comprises a jam determination unit that varies the conditions for performing a jam determination according to the thickness of the paper being conveyed.
The reason for this will be described.
In general, the judgment criteria for jams are set so that the transport distance is long in consideration of the slip of the paper. However, when the paper is transported through a plurality of drive sources, some of the drive sources step out. When a force is applied to force the conveyance, the thin paper with a small slip is forcibly conveyed over a long distance until the jam is judged, and the paper is damaged.

  Therefore, the present invention makes the optimum jam determination according to the paper thickness by changing the condition for performing the jam determination according to the paper thickness of the paper being conveyed, and prevents the paper from being damaged. be able to.

The image forming apparatus according to the present invention includes an image forming unit that forms an image on a recording medium and the above-described automatic paper conveying device.
With this configuration, it is unnecessary to provide a dedicated sensor for detecting the paper thickness, and it is possible to prevent an excessive shock from being generated when the calling unit comes into contact with the sheet bundle. Therefore, it is possible to prevent the generation of noise, protect the calling unit and the sheet bundle, and obtain an image forming apparatus provided with a low-cost automatic sheet conveying apparatus.

  The image reading apparatus according to the present invention includes an image reading unit that reads an image of the sheet at the processing position and the automatic sheet conveying apparatus described above.

  With this configuration, it is unnecessary to provide a dedicated sensor for detecting the paper thickness, and it is possible to prevent an excessive shock from being generated when the calling unit comes into contact with the sheet bundle. For this reason, it is possible to prevent the generation of noise, protect the calling means and the sheet bundle, and obtain an image reading apparatus provided with a low-cost automatic sheet conveying apparatus.

The image forming apparatus according to the present invention includes an image forming unit that forms an image on the sheet at the processing position and the above-described automatic sheet conveying apparatus.
With this configuration, it is unnecessary to provide a dedicated sensor for detecting the paper thickness, and it is possible to prevent an excessive shock from being generated when the calling unit comes into contact with the sheet bundle. Therefore, it is possible to prevent the generation of noise, protect the calling unit and the sheet bundle, and obtain an image forming apparatus provided with a low-cost automatic sheet conveying apparatus.

  As described above, it is unnecessary to provide a dedicated sensor for detecting the paper thickness, and it is possible to prevent an excessive shock from being generated when the calling means abuts against the sheet bundle, thereby preventing noise. In addition, it is possible to provide a low-cost automatic paper conveyance device, image reading device, and image forming device that can protect the calling means and the paper bundle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 19 are diagrams showing an embodiment of an automatic paper conveyance device, an image reading device provided with the automatic paper conveyance device, and an image forming apparatus provided with the automatic paper conveyance device and the image reading device according to the present invention. In the present embodiment, an example is shown in which the image forming apparatus is applied to a copying machine and the automatic paper conveying apparatus is applied to an ADF.

  In addition to the copying machine, the image forming apparatus can be applied to a facsimile machine, a printer device, a multifunction machine having a copying function and a facsimile function, and the like. Further, the image reading apparatus can be applied to a scanner apparatus, a facsimile apparatus, a multifunction machine having a copying function and a facsimile function, and the like.

  First, the configuration will be described. In FIG. 1, a contact glass 22a (see FIG. 2) made of a translucent member is provided on the upper surface of the main body 21a of the copying machine 21, and the upper surface of the main body adjacent to the contact glass 22a is made from the contact glass 22a. A slit glass 22b made of a light-transmitting member having a small area is also provided (see FIG. 2).

  Further, an ADF 23 as an automatic paper transport device is provided on the upper portion of the main body 21a, and the ADF 23 can be freely opened and closed so as to open and close the contact glass 22a via a hinge mechanism (not shown).

  The configuration of the ADF 23 will be described with reference to FIGS. FIG. 2 is a schematic configuration diagram of the ADF 23, and FIG. 3 is a block diagram of a control system of the ADF 23. In FIG. 2, the ADF 23 includes a document table 24 as a sheet placement table, and a document bundle P as a sheet bundle is placed on the document cable 24 so that the document surface faces upward. .

  On the table surface of the document table 24, document length detection sensors 25 to 27 are provided as paper size detection means for detecting the length of the document. The document length detection sensors 25 to 27 are respectively paired adjacent to each other. A light receiving element and a light emitting element are provided.

  Specifically, when light received from the light emitting element onto the original bundle P and reflected from the original bundle P is received by the light receiving element, the light receiving element converts the light into an electrical signal corresponding to the amount of received light and outputs the electrical signal to the controller 100.

  In addition, a table that associates the light amount and reflectance with the thickness of the document is provided in a memory (not shown), and the controller 100 refers to this table to determine the thickness of the document from the light amount and reflectance detected from the light receiving element. To do.

  Therefore, the document length detection sensors 25 to 27 are arranged on the table surface of the document table 24 so that at least whether the document size is vertical or horizontal can be determined. The controller 100 determines the conveyance direction length of the document bundle P placed on the document table 24 based on the information input from the light receiving element, and also determines the document bundle P based on the change in the light amount or the reflectance input from the light receiving element. Calculate the thickness. That is, the document length detection sensors 25 to 27 of the present embodiment use both a sensor that detects the length of the document bundle P and a sensor that detects the thickness of the document bundle P.

  A stopper claw 28 as a stopper member is provided on the downstream side of the document table 24 with respect to the document conveyance direction. The stopper claw 28 is a bump position where the leading edge of the document bundle P is bumped by the calling motor 101. The position is moved between (a position indicated by a broken line) and a retracted position (a position indicated by a solid line) where the document bundle P is retracted.

  Therefore, the leading end of the document bundle P is abutted when the stopper claw 28 is in the abutting position, so that the leading ends of the document bundle P are aligned. Further, the width direction of the document bundle P is abutted against a side fence (not shown) provided on the document table 24 so that positioning in a direction perpendicular to the transport direction is performed.

  When the stopper claw 28 moves downward, the stopper claw 28 is detected by the home position sensor 34, and the home position sensor 34 outputs detection information to the controller 100.

  Further, a set filler 29 and a document set sensor 30 are provided on the document cable 24 on the leading end side of the document bundle P, and the set filler 29 is disposed when the document bundle P is placed on the document table 24. When the document set sensor 30 changes from the undetected state to the detected state, the signal is output to the controller 100.

  The controller 100 is connected to the main body control unit 111 provided in the main body 21 a of the copying machine 21 via the I / F 107, and outputs a signal to the I / F 107. Based on this input signal, the main body control unit 111 shifts to a standby state for reading a document on the main body 21a side.

  A calling roller 31 as a calling means is provided above the stopper claw 28. The calling roller 31 is configured such that a driving force from the calling motor 101 is transmitted via a calling cam 126 described later. The call motor 101 and the cam mechanism are moved up and down between a position retracted from the original bundle P indicated by a solid line and a position abutting on the upper surface of the original bundle P indicated by a two-dot chain line. The calling motor 101 of this embodiment is a stepping motor, and the calling motor 101 and the calling cam 126 constitute a lifting member.

  When the calling roller 31 moves to the retracted position, the calling roller 31 is detected by the calling home position sensor 52. When the calling roller 31 is at the retracted position, the calling home position sensor 52 is controlled by the controller. By transmitting a detection signal to 100, the controller 100 can detect that the calling roller 31 is in the retracted position.

  Further, an operation unit 108 is provided on the main body 21a side, and when a print key of this operation unit is pressed and a document feed signal is transmitted from the main body control unit 111 to the controller 100 via the I / F 107, The controller 100 drives the call motor 101 to rotate forward so that the stopper pawl 28 is retracted downward from the document bundle P.

  When the stopper claw 28 moves to the retracted position, the stopper claw 28 is detected by the home position sensor 34. When the home position sensor 34 detects the stopper claw 28, the controller 100 turns the calling motor 101 off. By driving in reverse, the calling roller 31 is lowered to a position where it comes into contact with the document bundle P.

  At this time, the calling roller 31 starts feeding several (ideally one) originals on the original table 24 by the forward rotation of the paper supply motor 102. The fed document is fed to a separating / feeding means including a feeding belt 32 and a reverse roller 33 provided on the downstream side of the calling roller 31.

  The sheet feeding belt 32 is bridged by a driving roller 32a and a driven roller 32b, and moves around when the driving force is transmitted from the sheet feeding motor 102 to the driving roller 32a.

  When the paper feed motor 102 is driven to rotate forward, the paper feed belt 32 rotates in the paper feed direction (clockwise direction), and the reverse roller 33 has a torque limiter (not shown) built therein. When 102 is driven forward, it is rotated in the direction opposite to the paper feeding direction (clockwise direction). For this reason, the top document and the document below it are separated and only the top document is fed.

  Specifically, the reverse roller 33 is in contact with the paper feed belt 32 at a predetermined pressure, and is in direct contact with the paper feed belt 32 or in a state where it is in contact with one original sheet. The rotation force is set so that the rotation force is lower than the torque limiter torque when two or more originals enter between the paper feed belt 32 and the reverse roller 33. ing. For this reason, the reverse roller 33 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess original, thereby preventing double feeding.

  The separated document is detected by a separation sensor 51 serving as a separation sheet detecting unit provided on the downstream side of the sheet feeding belt 32, and the document detected by the separation sensor 51 is further conveyed by the sheet feeding belt 32. The controller 100 stops the forward driving of the paper feeding motor 102 when the paper is conveyed by a predetermined amount X mm from the time when the leading edge of the original is detected by the abutting sensor 35 provided on the downstream side of the paper feeding belt 32. .

  This predetermined amount Xmm is set to be larger than the distance from the contact sensor 35 to the nip portion of the pull-out roller pair (rotating member) 36, and is constant at the nip portion of the pull-out driving roller 36a and the pull-out driven roller 36b that are in sliding contact with each other. It is stopped in a state where the bending is formed.

  At this time, the calling motor 101 is driven to rotate forward in response to a command from the controller 100, so that the calling roller 31 is retracted from the upper surface of the document and the document is conveyed only by the conveying force of the paper feeding belt 32. It is possible to correct the bending (skew) of the document that is abutted against the nip portion of the pull-out driving roller 36a and the pull-out driven roller 36b and is generated during the separation conveyance.

  Further, the pull-out driving roller 36a and the pull-out driven roller 36b constitute a first skew correction means, and a second skew correction is provided on the downstream side of the original skew-corrected by the reverse rotation driving of the paper feed motor 102 after separation. It is conveyed toward a reading entrance roller pair (rotating member) 37 as means. The reading inlet roller pair 37 is constituted by a reading inlet driving roller 37a and a reading inlet driven roller 37b.

  When the paper feed motor 102 is driven in reverse rotation, the pull-out drive roller 36a is driven, but no driving force is transmitted to the calling roller 31 and the paper feed belt 32 due to the action of a one-way clutch (not shown).

  A document width sensor 38 is provided on the downstream side of the pull-out driving roller 36a and the pull-out driven roller 36b. A plurality of document width sensors 38 are arranged in the depth direction in FIG. It moves between the positions indicated by the chain line.

  When the document width sensor 38 detects a document, the document width sensor 38 moves to a position indicated by a two-dot chain line. Information on the width direction perpendicular to the transport direction of the document transported by the pull-out driving roller 36a and the pull-out driven roller 36b is obtained. The detection information is acquired and transmitted to the controller 100.

  Based on the combination of the document length detection information from the document size detection sensors 25 to 27 and the width detection information from the document width sensor 38, the controller 100 sets the document bundle P loaded on the document table 24 in the main body control unit 111. Send size information.

  Further, the controller 100 calculates the more accurate length of the document by counting the number of motor driving pulses corresponding to the distance conveyed while the leading edge and the trailing edge of the document are detected by the abutting sensor 35.

  Further, when the original is conveyed to the reading entrance roller pair 37 by driving the pull-out driving roller 36a, the original conveying speed is set to a high speed and the original is sent to the reading position 80 (processing position) on the slit glass 22b. The time is shortened, and in particular for the second and subsequent originals, productivity can be improved by shortening the paper gap with the previous original by this high-speed conveyance. When the leading edge of the document is detected by the reading entrance sensor 39, deceleration is started before the leading edge of the document enters the reading entrance roller pair 37.

  Further, the controller 100 drives and stops the paper feed motor 102 so that the conveyance distance is longer by Y mm than the distance from the reading inlet sensor 39 to the reading inlet roller pair 37, thereby stopping the stopped reading inlet roller pair. The document is stopped in a state where the leading edge of the document abuts against the nip portion 37 to form a certain amount of bending. As a result, it is possible to correct the skew generated when the document is conveyed by the pull-out roller pair 36. In the present embodiment, the reading entrance roller pair 37 constitutes a second skew correction means.

  If Ymm is set in the case of a thin paper document, it is set to Ymm + αmm in the case of a thick paper document, so that the abutting amount is set larger than that in the case of a thin paper document. This is to prevent damage when a thin paper original is made equal to the amount of a thick paper original.

  Further, the controller 100 transmits a registration stop signal to the main body control unit 111 via the interface means 107 when the document is temporarily stopped (resist stop) at the nip portion of the reading entrance roller pair 37.

  When the registration stop signal is transmitted, the controller 100 receives a reading start signal from the main body control unit 111, and reads so that the document whose registration has been stopped is conveyed at a conveyance speed corresponding to the reading magnification. The motor 103 is driven and the original is conveyed by the reading exit roller pair 40. The reading exit roller pair 40 includes a reading exit driving roller 40a and a reading exit driven roller 40b.

  Here, when the reading start signal is received before the leading edge of the document reaches the registration sensor 41 provided on the upstream side of the slit glass 22b, the registration non-stop reading operation is performed. In the resist non-stop reading operation, reading is performed while maintaining the reading conveyance speed without stopping the registration.

  The registration sensor 41 detects the leading edge of the document. When the registration sensor 41 detects the leading edge of the document, the controller 100 starts the pulse count of the reading motor 103, and the leading edge of the document is on the slit glass 22b. At the timing when the reading position 80 is reached, a gate signal indicating an effective image area in the sub-scanning direction is sent to the main body control unit 111. This gate signal is normally sent until the trailing edge of the document leaves the reading position 80.

  The document that has passed through the reading position 80 is conveyed by the reading exit roller pair 40 and the discharge roller 42, and is placed on the discharge tray 43 after the reading of the double-sided document or after the single-sided reading of the single-sided document is completed. The paper is ejected.

  The paper discharge roller 42 includes a paper discharge drive roller 42a, a paper discharge driven upper roller 42b, and a paper discharge driven lower roller 42c. A switching claw 44 is provided on the downstream side of the paper discharge roller 42.

  When carrying a double-sided document, the switching claw 43 is driven by the reversing solenoid 105 before the leading edge of the document that has passed through the reading position 80 at the time of reading the surface of the document reaches the paper discharge roller 42, and the two-dot chain line. It is designed to switch to the position indicated by.

  At this time, the document is conveyed to the switchback passage 46 by the paper discharge driving roller 42 a and the paper discharge driven roller 42 c driven by the reading motor 103 and the reverse roller pair 45 driven by the reverse motor 104.

  When the driving pulse of the reading motor 103 reaches a predetermined pulse after the trailing edge of the original is detected by the reading outlet sensor 47 provided on the downstream side of the pair of reading outlet rollers 40, the controller 100 causes the trailing edge of the original to be a discharge roller. It is determined that the valve 42 has exited, and the reverse solenoid 105 is turned off to move the switching claw 44 to the position indicated by the solid line.

  Further, as described above, after the driving pulse of the reading motor 103 reaches a predetermined pulse, the controller 100 drives the reverse motor 104 in the reverse direction to drive the reverse roller pair 45 in the reverse direction, thereby moving the document toward the pull-out roller pair 36. Switch back.

  At this time, the driving direction of the reading motor 103 is the same direction and the driving direction of the reversing motor 104 is reversed, and the reversing motor 104 and the reading motor 103 are driven at a high speed in order to shorten the processing time.

  In addition, when the document starts to switch back, the controller 100 drives the paper feeding motor 102 at a high speed to reversely feed the document toward the pull-out roller pair 36 after the drive pulse of the reversing motor 104 reaches a predetermined pulse.

  Further, when the trailing edge of the document conveyed in the refeed path 46 b is detected by the reverse sensor 49, the controller 100 stops the reverse driving of the reverse roller pair 45 based on the detection information from the reverse sensor 49. It has become.

  Thereafter, the skew of the document is corrected by the pull-out roller pair 36, one side of the document is read as described above, switched back by the switchback path 46a, and then conveyed toward the reading position 80 through the refeed path 46b. Then, the document is discharged to the discharge tray 43 by performing a reversing operation for providing the document surface without reading the document.

  A paper discharge sensor 50 is provided on the upstream side of the paper discharge roller 42. The paper discharge sensor 50 detects the trailing edge of the document and outputs a signal to the controller 100. Determines that the document has been discharged based on the detection information.

  5 to 8 are diagrams showing a drive system, FIG. 5 is a drive system from the calling motor 101, FIG. 6 is a drive system from the paper feed motor 102, FIG. 7 is a drive system from the reading motor 103, and FIG. A drive system from the reversing motor 104 is shown.

  In FIG. 5, the pulley 121 connected to the calling motor 101 is connected to the pulley 123 via the timing belt 122. When the pulley 123 is rotated by the paper feed motor 102, this rotation is transmitted from the pulley 123 to the pulley 124. The

  The pulley 124 is connected to the calling cam 126 via the pulley 125. When the calling motor 101 is driven to rotate forward, the calling cam 126 is rotated counterclockwise to move the calling roller 31 to the retracted position. When the call motor 101 is driven in reverse, the call cam 126 is rotated in the clockwise direction to move the call roller 31 to the contact position.

  The pulley 124 is connected to the stopper claw cam 129 via pulleys 127 and 128, and the stopper claw 28 is moved between the abutting position and the retracted position by the rotation of the stopper claw cam 129.

  In FIG. 6, a pulley 131 connected to the paper feed motor 102 is connected to a pulley 133 via a timing belt 132, and this pulley 133 is connected to a pulley 134.

  The pulley 134 is connected to the pulley 147 via pulleys 135, 136, 144, 145, and 146, and the pulley 147 is connected to the pulley 150 via the pulley 149. The pulley 150 is connected to a pulley 152 via a timing belt 151, and the pulley 152 is connected to a call pulley 153 connected to the call roller 31.

  For this reason, when the paper feeding motor 102 is driven to rotate in the clockwise direction, the pulley 131, the timing belt 132, the pulleys 133, 134, 135, 136, 144, 145, 146, 147, 149, 150, the timing belt 152 Then, the calling roller 31 is rotated in the clockwise direction via the calling pulley 153 to separate the upper document from the document bundle P.

  The pulley 147 is connected to a paper feed belt drive pulley 148 that drives the drive roller 32a of the paper feed belt 32. The pulley 148 rotates counterclockwise when the paper feed motor 102 is driven to rotate in the clockwise direction. The paper feed belt 32 is rotated in the direction of feeding the original bundle P by rotating in the direction.

  The pulleys 134, 136, and 144 each have a built-in one-way clutch, and the pulleys 134, 136, and 144 call only the clockwise driving force of the paper feeding motor 102 and transmit it to the pulley 153 and the paper feeding belt drive roller pulley 148. To do.

  The pulley 135 is connected to a reverse roller pulley 158 that rotates the reverse roller 33 via pulleys 137, 154, 155, 156, and 157. When the paper feed motor 102 rotates in the clockwise direction, the pulleys 137 and 154 are connected. By rotating the reverse roller 33 in the clockwise direction via 155, 156, 157, the document bundle P is rotated in the separating direction.

  The pulley 137 has a built-in one-way clutch, and the pulley 137 transmits only the driving force of the paper feeding motor 102 in the clockwise direction to rotationally drive the reverse roller 33.

  A pulley 139 is connected to the pulley 133, and the pulley 139 is connected to a pulley 139 that is coaxially connected to the pulleys 137 and 154 and is also connected to the pulley 140.

  The pulley 140 is connected to a pull-out driving roller pulley 143 via pulleys 141 and 142, and the pull-out driving roller pulley 143 is connected to a pull-out driving roller 36a.

  For this reason, when the paper feed motor 102 is driven reversely in the counterclockwise direction, the pulley 140 rotates in the counterclockwise direction, thereby causing the pull-out drive roller pulley 143 to rotate counterclockwise via the pulleys 142 and 141. The document is conveyed toward the reading position 80 by the pull-out roller pair 36a.

  In FIG. 7, a pulley 161 connected to the reading motor 103 is connected to a pulley 163 via a timing belt 162, and this pulley 163 is connected to the pulley 164.

  The pulley 164 is connected to pulleys 166 and 167 via a timing belt 165, and the pulley 167 is connected to a reading inlet roller pulley 168 for rotating the reading inlet driving roller 37a. For this reason, when the reading motor 103 is driven forward in the clockwise direction, the reading inlet driven roller 37a is moved via the pulley 161, the timing belt 162, the pulleys 163 and 164, the timing belt 165, the pulleys 166 and 167, and the reading inlet roller pulley 168. It rotates in the clockwise direction that is the transport direction.

  The pulley 167 includes a one-way clutch, and the pulley 167 transmits only the driving force of the reading motor 103 in the clockwise direction to the reading inlet roller pulley 168.

  A pulley 169 is connected to the reading inlet roller pulley 168, and this pulley 169 is connected to a reading outlet roller pulley 175 via a timing belt 174.

  The reading outlet roller pulley 175 is connected with a reading outlet driving roller 40a of the reading outlet roller pair 40, and the reading outlet driving roller 40a rotates counterclockwise as the conveying direction in accordance with the rotation of the reading outlet roller pulley 175 in the counterclockwise direction. Rotate in the direction.

  Further, a discharge roller pulley 179 is connected to the timing belt 174, the discharge roller pulley 179 is connected to the discharge drive roller 42a of the discharge roller 42, and the discharge drive roller 42a rotates counterclockwise of the discharge roller pulley 179. With the rotation in the direction, it rotates in the clockwise direction that is the transport direction.

  The timing belt 174 is connected to pulleys 177 and 178 for applying a constant tension to the timing belt 174 to move the timing belt 174 around.

  The pulley 169 is connected to the pulley 171 of the jam processing dial 172 via the tension belt 170. The jam processing dial 172 is operated by an operator to remove the jammed paper from the conveyance path. When the jam processing dial 172 is rotated, a driving force is transmitted to the pulley 169 via the tension belt 170. As the pulley 169 moves around the timing belt 174, the jammed paper on the conveyance path is removed.

  In FIG. 8, a pulley 191 connected to the reversing motor 104 is connected to a pulley 193 via a timing belt 192, and this pulley 191 is driven by the reversing motor 104 in the forward / reverse direction so that the reversing roller driving roller 45 a of the reversing roller pair 45. Is rotated forward and backward.

  On the other hand, the controller 100 according to the present embodiment controls the lowering of the calling roller 31 by driving the calling motor 101 according to the thickness of the document bundle P detected by the document size detection sensors 25 to 27. The controller 100 and the calling motor 101 constitute a descending state control means.

  As a specific control of the lowered state, as shown in FIG. 2, the difference between the distance L2 from the retracted position of the calling roller 31 to the document table 24 and the thickness L3 of the acquired document bundle P is obtained, and the calling roller is determined. By calculating the distance L1 from 31 to the top of the document bundle P, the number of pulses P (total descending distance) required for the distance L1 (until the calling roller 31 contacts the document bundle P) is calculated.

  When the necessary number of pulses P is determined, as shown in FIG. 4, the number of pulses P1 of the calling motor 101 necessary for accelerating from the home position of the calling roller 31 to the maximum speed Vmax and the steady state in which the maximum speed Vmax is maintained. From the pulse number P, the pulse number T that maintains the steady state is determined by subtracting the pulse number P2 required for decelerating from the pulse number P to the speed V at which the calling roller 31 comes into contact with the document bundle P. That is, the relationship of the number of pulses P> P1 + P2 of the calling motor 101 is established.

  When the calling motor 101 is driven by the number of pulses T and the deceleration of the calling roller 31 is started after the calling motor 101 is in a steady state, the calling roller 31 is always brought into contact with the document bundle P at a constant speed V. it can.

  The main body 21a is provided with a display unit 48, and the controller 100 determines that the thickness of the document bundle P is equal to or larger than the allowable number of stacks based on detection information from the document size detection sensors 25-27. In addition, the display unit 48 is displayed to alert the user. In the present embodiment, the controller 100 and the display unit 48 constitute alarm means.

  The controller 100 also determines the thickness of the original bundle P placed on the original cable 24 based on the detection information from the original size detection sensors 25 to 27 and the original bundle immediately after the uppermost original is separated from the original bundle P. The thickness per sheet of the separated document is calculated by comparing with the thickness of the sheet, and constitutes a separation sheet thickness calculation means.

  Further, the separation distance S between the stopper claw 28 and the separation sensor 51 and the separation distances S1 and S2 (where S1 and S2 are equivalent to Sn) of the respective document size detection sensors 25 to 27 are such that S> S1 and S2. Is set.

  For this reason, since the separation distance S between the separation sensor 51 and the stopper claw 28 is larger than the separation distances S1 and S2 of the document size detection sensors 25 to 27, before the leading edge of the document reaches the separation sensor 51, The end always passes through any one of the document size detection sensors 25 to 27, and the controller 100 determines the thickness per separated document based on the state immediately before and after the separation of the topmost document. Can be calculated.

  In addition, the controller 100 changes the amount of abutment between the pull-out roller pair 36 and the reading entrance roller pair 37 according to the paper thickness of the separated document calculated based on the detection information from the document size detection sensors 25 to 27. ing.

  The abutting amount is an amount by which the leading edge of the original abuts against the nip portion of the pull-out roller pair 36 and the reading entrance roller pair 37. As described above, the nip of the pull-out roller pair 36 from the abutting sensor 35 is used. It is determined by driving the paper feed motor 102 by Xmm or Ymm set larger than the distance to the part.

  In the present embodiment, if Xmm or Ymm is set for a thin paper document, the amount of abutment is larger than that for a thin paper document by setting Xmm + αmm or Ymm + αmm for a thick paper document. .

  Further, the controller 100 drives the reading motor 103 in accordance with the paper thickness of the separated document calculated based on the detection information from the document size detection sensors 25 to 27, thereby changing the rotation speed of the paper discharge roller 42. The discharge speed of the document discharged to the discharge tray 43 is variable, and the discharge motor 103 together with the reading motor 103 is configured.

  Also, calculation is performed based on detection information from the bump sensor 35, the reading inlet sensor 39, the registration sensor 41, the reading outlet sensor 47, the reverse sensor 49, the paper discharge sensor 50, and the detection information from the document size detection sensors 25-27. The condition for performing the jam determination is made different according to the paper thickness of the separated original, and a jam determination unit is configured.

  Specifically, the jam determination criterion is set so that the document transport distance is long in consideration of the slip of the document. However, when the jam occurs, some of the paper feed motor 102, the reading motor 103, and the reverse motor 104 are If a force is applied to step out and force the conveyance, thin paper originals with small slips will be forcibly conveyed over long distances before being judged as jammed, resulting in damage to the originals. . For this reason, in the case of a thin paper document, a thick paper document is quickly judged for jamming, and the paper feed motor 102, the reading motor 103, and the reversing motor 104 are immediately stopped.

  On the other hand, an image reading device 81 is provided in the main body 21 a of the copying machine 21, and image information read by the image reading device 81 is transferred to the photosensitive drum 83 by the writing unit 82. Irradiated.

  The image reading device 81 includes a light source 81a that illuminates the original on the contact glass 22a or the slit glass 22b, a first mirror 81b, a second mirror 81c, a third mirror 81d that reflect light reflected from the original, A lens 81e that forms an image of the light reflected from the three mirrors 81d on the CCD image sensor 81f and a CCD image sensor 81f that converts the light imaged by the lens 81e into an electrical signal are provided.

  The light source 81a and the first mirror 81b are attached to a first traveling body (not shown), and the second mirror 81c and the third mirror 81d are attached to the second traveling body, and the first traveling body and the second traveling body. The body moves in FIG. 1 along the contact glass 22a and the slit glass 22b.

  When the first traveling body and the second traveling body read a document placed on the contact glass 22a, the first traveling body and the second traveling body are moved in the left-right direction in FIG. 1 below the contact glass 22a, and the document that passes through the slit glass 22b is scanned. When reading, it is stopped below the slit glass 22b.

  The writing unit 82 irradiates a laser beam light-modulated according to image information read by the image reading device 81, and exposes the surface of the charged photosensitive drum 83 with the laser beam.

  Around the photosensitive drum 83, a developing device 86, a transfer belt 87, a cleaning device 88, a charging device and a static eliminating device (not shown) that form an image forming unit together with the photosensitive drum 83 are provided. The charging device controls the corona discharge with a positive charge in the dark by a grid to charge the surface of the photosensitive drum to a constant potential.

  The writing unit 82 irradiates a laser diode containing image information onto the photosensitive drum 83 charged at this constant potential to remove negative charges on the photosensitive drum 83 to form an electrostatic latent image.

  The developing device forms a visible image by attaching negatively charged toner to the electrically removed portion on the photosensitive drum 83. A positive bias is applied to the transfer belt 87, and the transfer belt 87 transfers a negatively charged visible image onto a transfer sheet (paper) as a recording medium for conveyance.

  The cleaning device 88 is provided with a cleaning blade, and scrapes off the toner remaining on the photosensitive drum 83. The static eliminator turns on the LED to remove the residual charge on the photosensitive drum 83 and prepares to form a new image on the next transfer sheet.

The transfer paper on which such an image is formed is conveyed to the fixing device 90, and the toner image is fixed on the transfer paper by the fixing device 90.
The main body 21a is provided with storage cassettes 91 to 95 in which transfer papers S1 to S5 of different sizes are stored. The transfer paper stored in the storage cassettes 91 to 95 is called by calling rollers 91a to 95a. After the sheets are fed, they are slidably contacted with the sheet feeding rollers 91b to 95b and the sheet feeding rollers 91b to 95b rotating in the transport direction and separated by the reverse rollers 91c to 95c rotating in the separating direction, and then the relay roller pairs 96, 97 Are conveyed to the registration roller pair 98, and are timed by the registration roller pair 98 to be conveyed to a conveyance path (processing position) between the photosensitive drum 83 and the transfer belt 87.

  Next, the document conveying operation will be described based on the flowcharts of FIGS. Note that the flowcharts of FIGS. 9 to 19 are conveyance control programs controlled by the controller 100.

  First, in FIG. 9, the controller 100 determines whether or not the document bundle P is set on the document table 24 based on the detection information from the document size detection sensors 25 to 27 (step S1). When the document bundle P is set on the document table 24, the thickness information of the document bundle P is acquired based on the detection information from the document size detection sensors 25 to 27 (step S2). In step S2, the thickness of the document bundle P is calculated based on an electrical signal corresponding to the light amount or the reflectance input from the light receiving elements of the document size detection sensors 25 to 27.

  Next, the controller 100 determines whether or not the number of document bundles P set on the document table 24 is equal to or less than the allowable stacking number (step S3). In step S3, it is indirectly determined whether the number of document bundles P is equal to or less than the allowable stacking number by determining whether the thickness of the document bundle P is equal to or greater than the allowable thickness.

  If the controller 100 determines in step S3 that the number of document bundles P set on the document table 24 is greater than or equal to the allowable number of stacks, a warning such as “The document cannot be conveyed” is displayed on the display unit 48. The text is displayed and the process is terminated (step S4), and when it is determined that the number of document bundles P set on the document table 24 is equal to or less than the allowable stacking number, the stop timing of the calling roller 31, that is, The number of pulses of the calling motor 101 until the calling roller 31 comes into contact with the document bundle P is calculated (step S5).

  Next, when the print key of the operation unit 108 is pressed, a document feed signal is transmitted from the main body control unit 111 to the controller 100 via the I / F 107, so the controller 100 moves the feed motor 102 in the clockwise direction. Drive forward (step S6). At this time, the stopper claw 28 is retracted from the front end of the document bundle P.

  Next, the controller 100 determines whether or not the stopper pawl 31 has moved to the retracted position based on the detection information from the home position sensor 34 (step S7). If the stopper pawl 31 has moved to the retracted position, a call is made. The motor 101 is driven in reverse (step S8).

  For this reason, the calling roller 31 is lowered from the retracted position so as to contact the document bundle P. Then, the controller 100 determines whether or not the calling motor 101 has reached the steady state indicated by T in FIG. 4 (step S9). If the calling motor 101 has entered the steady state, the advance pulse of the calling motor 101 from the steady state is determined. Counting (P2 counting in FIG. 4) is started (step S10).

  Next, the controller 100 determines whether or not the count value has reached a predetermined pulse (that is, P2 in FIG. 4) (step S11), and when it reaches the predetermined pulse, stops the calling motor 101 (step S12). . For this reason, the calling roller 31 comes into contact with the uppermost portion of the document bundle P.

  Next, the controller 100 acquires the length of the document based on the detection information from the document size detection sensors 25 to 27 (step S13), and then drives the paper feed motor 102 to rotate in the clockwise direction as shown in FIG. (Step S14). Therefore, after the uppermost original is separated from the original bundle P by the calling roller 31, the uppermost original is separated by the paper feed belt 32 and the reverse roller 33.

  Next, the controller 100 determines whether or not the separation sensor 51 is turned on (step S15). If the separation sensor 51 is turned on, the controller 100 determines that the leading edge of the separated document is detected by the separation sensor 51 and determines the document size. Based on the detection information from the detection sensors 25 to 27, the thickness information of the document bundle P is acquired again (step S16).

  Next, the controller 100 compares the thickness of the original bundle P before the separation of the original and the thickness of the original bundle P immediately after the separation of the original based on the detection information from the original size detection sensors 25 to 27 to separate the separation. The thickness per document is calculated (step S17).

  Next, the controller 100 determines the first abutting amount according to the thickness of the original by the pull-out roller pair 36 (step S18), and then determines the second abutting amount according to the thickness of the original by the reading entrance roller pair 37. (Step S19).

  Next, the controller 100 determines the discharge speed according to the thickness of the document (step S20), and then determines the jam detection condition according to the thickness of the document (step S21). Next, the controller 100 drives the paper feed motor 102 in the counterclockwise direction (step S22).

  Next, the controller 100 determines whether or not the bump sensor 35 is turned on (step S23). If the bump sensor 35 is not turned on, the controller 100 determines whether the jam detection time is over based on the jam detection condition acquired in step S21. It is determined whether or not (step S25).

  When the controller 100 determines that the jam detection time is over, it determines that the jam has not been reached and displays the jam on the display unit 48 (step S26). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper document in the case of the thin paper document, the reading motor 103 is immediately stopped to control the damage of the thin paper document. .

  On the other hand, when the abutting sensor 35 is on in step S23, the first abutting amount is counted (step S24). That is, the controller 100 starts counting the drive pulses of the paper feed motor 102 corresponding to a predetermined amount Xmm set larger than the distance between the abutting sensor 35 and the pull-out roller pair 36. Further, as described above, the predetermined amount Xmm is set to a different value depending on the thick paper and the thin paper.

  Next, as shown in FIG. 11, the controller 100 drives the call motor 101 in the counterclockwise direction (step S27), and then determines whether the call roller 31 has moved to the retracted position (step S28). When the calling roller 31 has moved to the retracted position, the calling motor 101 is stopped (step S29).

  Next, the controller 100 determines whether or not the pulse count of the paper feed motor 102 has reached a predetermined pulse that corresponds to the first abutting amount (corresponding to Xmm) (step S30), and when the pulse count reaches the predetermined pulse. Drives the feed motor 102 in reverse at high speed.

  When the paper feed motor 102 reaches a predetermined pulse, the original is pressed against the pull-out roller pair 36 with a predetermined amount of deflection, and the skew of the original is corrected. When the paper feed motor 102 is driven in reverse, the pull-out roller pair 36 is driven. However, since the driving force is not transmitted to the calling roller 31 and the paper feed belt 32 by the action of the one-way clutch of the pulley 140, the document is pulled out. It is conveyed by the roller pair 36.

  Next, it is determined whether or not the document width sensor 38 is turned on (step S32). When the document width sensor 38 is turned on, the controller 100 obtains the document width information based on the detection information from the document width sensor 38. Obtain (step S33). As a result, the controller 100 can grasp the size information of the document bundle P stacked on the document table 24 based on the combination of the document length information from the document size detection sensors 25 to 27 and the width information from the document width sensor 38. it can.

  At this time, the document is nipped between the pull-out roller pair 36 and the reading entrance roller pair 37 and conveyed toward the reading position 80. At this time, the document conveyance speed is set to a high speed to shorten the processing time for feeding the document to the reading position 80. In particular, productivity of the second and subsequent originals can be improved by shortening the gap between the original and the previous original by this high-speed conveyance.

  Next, the controller 100 determines whether or not the mixed loading mode is turned off (step S34). If the mixed loading mode is turned off, the document bundle loaded on the document table 24 in the main body control unit 111 is checked. The size information of P is transmitted (step S35).

  Next, as shown in FIG. 12, the controller 100 determines whether or not the leading edge of the document has been detected by the reading inlet sensor 39 (step S36). If the reading inlet sensor 39 is not turned on, the jam acquired in step S21. It is determined whether the jam detection time is over based on the detection condition (step S41).

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the leading edge detection has not been reached and displays a jam on the display unit 48 (step S42). The jam detection condition is set so that the jam detection time is shorter in the case of a thin paper document than in the case of a thick paper document, so that the paper feed motor 102 is immediately stopped to reduce damage to the thin paper document. To do.

  On the other hand, if the reading inlet sensor 39 is on in step S36, the second abutting amount is counted (step S37). That is, the controller 100 starts counting the driving pulses of the paper feed motor 102 corresponding to a predetermined amount Ymm set larger than the distance between the reading inlet sensor 39 and the reading inlet roller pair 37. Further, as described above, the predetermined amount Ymm is set to a different value depending on the thick paper and the thin paper.

  Next, the controller 100 determines whether or not the pulse count of the paper feed motor 102 has reached a predetermined pulse corresponding to the second abutting amount (Ymm) (step S38), and when the pulse count has reached the predetermined pulse. Stops the paper feed motor 102 (step S39), transmits a registration stop signal to the main body control unit 111 (step S40), and ends the conveyance control up to the reading position 80. When the paper feed motor 102 reaches a predetermined pulse, the original is pressed against the reading entrance roller pair 37 with a predetermined amount of bending, and the original skew is corrected.

  FIG. 13 is a flowchart of a document conveyance control program at the time of reading. In FIG. 13, the controller 100 determines whether or not the mode is the single-sided mode (step S51). If the controller 100 determines that the mode is the single-sided mode, the speed of the reading motor 103 is set from the reading magnification (step S52). Subsequently, when a reading start signal is received from the main body control unit 111, an original reading operation is started.

  The controller 100 drives the reading motor 103 in the normal direction to drive the reading inlet roller pair 37 and the reading outlet roller pair 40 at a conveyance speed corresponding to the reading magnification (step S53). Next, the controller 100 determines whether or not the leading edge of the document is detected by the registration sensor 41 (step S54). When the leading edge of the document is detected, the pulse count of the reading motor 103 is started (step S55).

  Next, the controller 100 determines whether or not the pulse count value of the reading motor 103 is a predetermined surface pulse corresponding to the distance between the registration sensor 41 and the reading position 80 on the slit glass 22b (step S56).

  When the controller 100 determines that the count value has reached the predetermined surface pulse, the controller 100 determines whether or not the correction pulse considering the slip ratio of the document has become the predetermined surface pulse (step S57).

  When the controller 100 determines that the correction pulse has reached the surface predetermined pulse, a gate signal indicating an effective image area in the sub-scanning direction is sent to the main body control unit 111 at the timing when the leading edge of the document reaches the reading position 80. After sending (step S59), the count of the surface gate count is started (step S59).

  Next, the controller 100 determines whether or not the leading edge of the document is detected by the paper discharge sensor 50 (step S60). If it is determined that the leading edge of the document is not detected by the paper discharge sensor 50, step S21 is performed. Whether or not the jam detection time is over is determined based on the jam detection condition acquired in step S61.

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the paper discharge has not reached and displays a jam on the display unit 48 (step S62). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper document in the case of the thin paper document, the reading motor 103 is immediately stopped to control the damage of the thin paper document. .

  On the other hand, if the paper discharge sensor 50 is on in step S60, the controller 100 determines whether or not the registration sensor 41 is off as shown in FIG. 14 (step S63), and the registration sensor 41 is not off. Is determined, it is determined whether or not the jam detection time is over based on the jam detection condition acquired in step S21 (step S64).

  If the controller 100 determines that the jam detection time has expired, it determines that the resist stay jam has occurred and displays a jam on the display unit 48 (step S65). Further, the jam detection condition is set to a time in which a jam detection time is shorter than that of a thick paper document in the case of a thin paper document, so that the driving of the reading motor 103 is immediately stopped.

  On the other hand, when the controller 100 determines that the registration sensor 41 is off, the controller 100 starts a rear end count for counting pulses of the reading motor 103 (step S66).

  Next, the controller 100 determines whether or not the pulse count value of the reading motor 103 has reached the predetermined surface pulse (step S67), and if it is determined that the predetermined surface pulse has been reached, the gate count value is the original document. It is determined whether or not it has become larger than the length (step S68).

  If the controller 100 determines that the gate count value is greater than the document length, the controller 100 stops transmitting a gate signal indicating an effective image area in the sub-scanning direction (step S69).

  Next, the controller 100 determines whether or not the paper discharge sensor 50 has been turned off (step S70). If it is determined that the paper discharge sensor 50 has not been turned off, the jam detection condition acquired in step S21. Based on this, it is determined whether or not the jam detection time is over (step S72).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the paper discharge stays jam and displays a jam on the display unit 48 (step S73). Further, the jam detection condition is set to a time in which a jam detection time is shorter than that of a thick paper document in the case of a thin paper document, so that the driving of the reading motor 103 is immediately stopped.

  If the controller 100 determines that the paper discharge sensor 50 has been turned off, the controller 100 transmits a signal indicating the completion of paper discharge to the main body control unit 111 (step S71), and ends the process.

  On the other hand, if the controller 100 determines in step S51 that the mode is not the single-sided mode, it sets the speed of the reading motor 103 from the reading magnification as shown in FIG. 15 (step S81), and then reads from the main body control unit 111. When the start signal is received, the document reading operation is started.

  The controller 100 drives the reading motor 103 in the normal direction to drive the reading inlet roller pair 37 and the reading outlet roller pair 40 at a conveying speed corresponding to the reading magnification (step S82). Next, the controller 100 determines whether or not the registration sensor 41 is turned on (step S83). If the registration sensor 41 is turned on, the controller 100 starts counting pulses of the reading motor 103 (step S84).

  Next, the controller 100 determines whether or not the pulse count value of the reading motor 103 has become a predetermined surface pulse corresponding to the distance between the registration sensor 41 and the reading position 80 on the slit glass 22b (step S85). If it is determined that the value has reached the predetermined surface pulse, it is determined whether or not the correction pulse considering the slip ratio of the document has become the predetermined surface pulse (step S86).

  When the controller 100 determines that the correction pulse has reached the surface predetermined pulse, a gate signal indicating an effective image area in the sub-scanning direction is sent to the main body control unit 111 at the timing when the leading edge of the document reaches the reading position 80. Transmit (step S87).

  At this time, the document is conveyed by setting the driving speed of the reading motor 103 to a conveyance speed corresponding to the thickness of the document. In the case of a thin paper document, this conveyance speed is set to be faster than that of a thick paper document.

  Next, after starting the front gate count (step S88), the controller 100 determines whether or not the leading edge of the document is detected by the reading exit sensor 47 (step S89).

  If the controller 100 determines that the leading edge of the document is not detected by the reading exit sensor 47, the controller 100 determines whether or not the jam detection time is over based on the jam detection condition acquired in step S21 (step S90).

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the paper discharge failure has occurred and displays a jam on the display unit 48 (step S91). Further, the jam detection condition is set to a time in which a jam detection time is shorter than that of a thick paper document in the case of a thin paper document, so that the driving of the reading motor 103 is immediately stopped.

  If the controller 100 determines that the reading outlet sensor 47 is on, the reversing solenoid 45 is used before the leading edge of the document that has passed through the reading position 80 at the time of reading the surface of the document reaches the discharge roller 42. Is turned on to switch the switching claw 44 to the position indicated by the two-dot chain line and the reversing motor 104 is driven (step S92).

  For this reason, the paper is driven on the switchback passage 46 a by the paper discharge driving roller 42 a and the paper discharge driven roller 42 b driven by the reading motor 103 and the reverse roller pair 45 rotated by the normal rotation drive of the reverse motor 104.

  Next, the controller 100 determines whether or not the reversing sensor 49 is turned on (step S93). If it is determined that the reversing sensor 49 is not turned on, the controller 100 is based on the jam detection condition acquired in step S21. It is then determined whether or not the jam detection time is over (step S94).

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the jam has not been reversed and displays a jam on the display unit 48 (step S95). Further, the jam detection condition is set to a time in which a jam detection time is shorter than that of a thick paper document in the case of a thin paper document, so that the driving of the reading motor 103 is immediately stopped.

  If the controller 100 determines that the reversal sensor 49 is on, as shown in FIG. 16, the controller 100 determines whether or not the registration sensor 41 is turned off (step S96). If it is determined that the jam detection time has not been turned off, it is determined whether or not the jam detection time is over based on the jam detection condition acquired in step S21 (step S97).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the jam is a resist retention jam and displays a jam on the display unit 48 (step S98). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the reading motor 103 and the reverse motor 104 are immediately stopped to reduce the damage of the thin paper original. To control.

  On the other hand, if the controller 100 determines that the registration sensor 41 is turned off in step S96, the controller 100 counts the pulses of the reading motor 103 from the state in which the trailing edge of the document is not detected by the registration sensor 41. The end count is started (step S99).

  Next, the controller 100 determines whether or not the count value of the pulse of the reading motor 103 has reached the predetermined surface pulse (step S100), and if it is determined that the predetermined surface pulse has been reached, the gate count value is the original document. It is determined whether or not it has become larger than the length (step S101).

  When the controller 100 determines that the gate count value has become larger than the document length, the controller 100 stops transmitting a gate signal indicating an effective image area in the sub-scanning direction (step S102).

  Next, the controller 100 determines whether or not the reading outlet sensor 47 is turned off (step S103). If the reading outlet sensor 47 is turned on, the jam detection time is exceeded based on the jam detection condition acquired in step S21. Whether or not (step S104).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the paper discharge stays jam and displays a jam on the display unit 48 (step S105). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the driving of the reading motor 103 and the reverse motor 104 is immediately stopped.

  If the controller 100 determines that the reading exit sensor 47 is turned off, the controller 100 determines whether or not the reading motor 103 has been driven by a predetermined pulse after the trailing edge of the document is detected by the reading exit sensor 47. (Step S106).

  If the controller 100 determines that the reading motor 103 has been driven by a predetermined pulse, it determines that the trailing edge of the document has slipped out of the discharge driving roller 42a and the discharge upper driven roller 42b, and turns off the reverse solenoid 105. To return the switching claw 44 to the position of the solid line. Further, after a predetermined pulse, the reversing motor 104 is driven to rotate at a high speed to rotate the reversing roller pair 45 and the reading motor 103 is accelerated (step S107), and the document is transferred to the pull-out roller pair 36 on the refeed path 46b. Transport toward you.

At this time, the driving direction of the reading motor 103 is the same direction, the driving direction of the reversing motor 104 is the reverse direction, and the reversing motor 104 and the reading motor 103 are driven at high speed, so that the processing time can be shortened.
Next, the controller 100 determines whether or not the leading edge of the document has been detected by the reversing sensor 49 and the reversing motor 104 has been driven by a predetermined pulse (step S108). 102 is driven at high speed in the counterclockwise rotation direction, which is the direction for driving the pull-out roller pair 36 (step S109).

  Next, as shown in FIG. 17, the controller 100 determines whether or not the reverse sensor 49 is turned off (step S110), and if it is determined that the reverse sensor 49 is turned off, the reverse motor 104 is turned off. Stop (step S111).

  Next, the controller 100 determines whether or not the reading inlet sensor 39 is turned on (step S112). If the reading inlet sensor 39 is not turned on, the controller 100 detects a jam based on the jam detection condition acquired in step S21. It is determined whether or not the detection time is over (step S113).

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the leading edge detection has not reached and displays a jam on the display unit 48 (step S114). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper document in the case of the thin paper document, the reading motor 103 is immediately stopped to control the damage of the thin paper document. .

  If the controller 100 determines in step S112 that the reading entrance sensor 39 is turned on, the controller 100 determines whether or not the registration sensor 41 is turned on (step S115), and the registration sensor 41 is not turned on. In this case, it is determined whether or not the jam detection time is over based on the jam detection condition acquired in step S21 (step S116).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that it is a resist retention jam and displays a jam on the display unit 48 (step S117).

  If the controller 100 determines that the registration sensor 41 is turned on in step S115, the controller 100 drives the reading motor 103 to rotate forward and starts counting pulses of the reading motor 103 (step S118).

  Next, the controller 100 determines whether or not the pulse count value of the reading motor 103 has become a predetermined front surface pulse corresponding to the distance between the registration sensor 41 and the reading position 80 on the slit glass 22b (step S119), and the count value is the back surface. If it is determined that the predetermined pulse has been reached, it is determined whether or not the correction pulse considering the slip ratio of the document has become a predetermined pulse on the front surface (step S120).

  When the controller 100 determines that the correction pulse has reached the predetermined back side pulse, a gate signal indicating an effective image area in the sub-scanning direction is sent to the main body control unit 111 at a timing when the leading edge of the document reaches the reading position 80. After sending out (step S121), the back gate count starts (step S122).

  Next, the controller 100 determines whether or not the reading outlet sensor 47 is turned on (step S123). If it is determined that the reading outlet sensor 47 is not turned on, the jam detection condition acquired in step S21 is satisfied. Based on this, it is determined whether or not the jam detection time is over (step S124).

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the paper discharge has not reached and displays a jam on the display unit 48 (step S125). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper document in the case of the thin paper document, the reading motor 103 is immediately stopped to control the damage of the thin paper document. .

  If the controller 100 determines in step S123 that the reading exit sensor 47 is ON, the controller 100 reverses the leading edge of the document that has passed through the reading position 80 when reading the surface of the document before reaching the discharge roller 42. The solenoid 45 is turned on to switch the switching claw 44 to the position indicated by the two-dot chain line, and the reversing motor 104 is driven (step S126).

  For this reason, the paper is driven on the switchback passage 46 a by the paper discharge driving roller 42 a and the paper discharge driven roller 42 b driven by the reading motor 103 and the reverse roller pair 45 rotated by the normal rotation drive of the reverse motor 104.

  Next, the controller 100 determines whether or not the reversing sensor 49 is turned on as shown in FIG. 18 (step S127). If it is determined that the reversing sensor 49 is not turned on, step S21 is performed. Whether or not the jam detection time is over is determined based on the jam detection condition acquired in step S128.

  If the controller 100 determines that the jam detection time has expired, the controller 100 determines that the jam has not been reversed and displays a jam on the display unit 48 (step S129). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the reading motor 103 and the reverse motor 104 are immediately stopped to reduce the damage of the thin paper original. To control.

  If the controller 100 determines in step S127 that the reversal sensor 49 is turned on, the controller 100 determines whether or not the registration sensor 41 is turned off (step S130), and the registration sensor 41 is not turned off. If it is determined that the jam detection time is exceeded, it is determined whether or not the jam detection time is over based on the jam detection condition acquired in step S21 (step S131).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the resist stay jam has occurred and displays a jam on the display unit 48 (step S132). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the reading motor 103 and the reverse motor 104 are immediately stopped to reduce the damage of the thin paper original. To control.

  If the controller 100 determines in step S130 that the registration sensor 41 has been turned off, the trailing edge count that counts the pulses of the reading motor 103 from the state in which the trailing edge of the document has not been detected by the registration sensor 41 is detected. Is started (step S133).

  Next, the controller 100 determines whether or not the count value of the pulse of the reading motor 103 has reached the predetermined backside pulse (step S134). It is determined whether or not it has become larger than the length (step S135).

  When the controller 100 determines that the gate count value has become larger than the document length, the controller 100 stops transmission of a gate signal indicating an effective image area in the sub-scanning direction (step S136).

  Next, the controller 100 determines whether or not the reading outlet sensor 47 is turned off (step S137), and if it is determined that the reading outlet sensor 47 is not turned off, the jam detection condition acquired in step S21. Based on this, it is determined whether or not the jam detection time is over (step S138).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the paper discharge stays jam and displays a jam on the display unit 48 (step S139). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the driving of the reading motor 103 and the reverse motor 104 is immediately stopped.

  If the controller 100 determines in step S137 that the reading exit sensor 47 has been turned off, whether or not the reading motor 103 has been driven by a predetermined pulse after the trailing edge of the document is detected by the reading exit sensor 47. Is determined (step S140).

  If the controller 100 determines that the reading motor 103 has been driven by a predetermined pulse, it determines that the trailing edge of the document has slipped out of the discharge driving roller 42a and the discharge upper driven roller 42b, and turns off the reverse solenoid 105. To return the switching claw 44 to the position of the solid line. Further, after a predetermined pulse, the reversing motor 104 is driven to rotate at a high speed to rotate the reversing roller pair 45 and the reading motor 103 is accelerated (step S141), and the document is transferred to the pull-out roller pair 36 on the refeed path 46b. Transport toward you. This transport process is a third document reversal operation for page alignment of the document after reading both sides of the document, and the document surface is not read.

  At this time, the driving direction of the reading motor 103 is the same direction, the driving direction of the reversing motor 104 is the reverse direction, and the reversing motor 104 and the reading motor 103 are driven at high speed, so that the processing time can be shortened.

  Next, the controller 100 determines whether or not the reversing motor 104 has been driven by a predetermined pulse after the leading edge of the document is detected by the reversing sensor 49 (step S142). The paper motor 102 is driven at a high speed in the counterclockwise direction that is the direction for driving the pull-out roller pair 36 (step S143).

  Next, as shown in FIG. 19, the controller 100 determines whether or not the reverse sensor 49 is turned off (step S144), and stops driving the reverse motor 104 (step S145).

  Next, the controller 100 determines whether or not the paper discharge sensor 50 is turned off (step S146), and if it is determined that the paper discharge sensor 50 is not turned off, the jam detection condition acquired in step S21. Based on this, it is determined whether or not the jam detection time is over (step S147).

  If the controller 100 determines that the jam detection time is exceeded, the controller 100 determines that the jammed paper jam has occurred and displays a jam on the display unit 48 (step S148). Further, since the jam detection condition is set to a time when the jam detection time is shorter than that of the thick paper original in the case of the thin paper original, the reading motor 103 and the reverse motor 104 are immediately stopped to reduce the damage of the thin paper original. To control.

  On the other hand, if the controller 100 determines in step S146 that the paper discharge sensor 50 has been turned off, the controller 100 stops driving the paper feed motor 102 and the reading motor 103 (step S149), and then discharges to the main body control unit 111. A signal indicating paper completion is transmitted (step S150), and the process ends.

  As described above, in the present embodiment, the document size detection sensors 25 to 27 that detect the length in the conveyance direction of the document bundle P placed on the document table 24 are replaced with the thickness of the document bundle P placed on the document table 24. Since the lowering control of the calling roller 31 is performed based on the thickness information of the document bundle P detected by the document size detection sensors 25 to 27, the sheet thickness is detected. It is unnecessary to provide a dedicated sensor, and it is possible to prevent an excessive shock from occurring when the calling roller 31 comes into contact with the document bundle P.

  For this reason, it is possible to prevent the generation of noise, protect the calling roller 31 and the document bundle P, and reduce the manufacturing cost of the ADF 23. As a result, the manufacturing cost of the copying machine 21 can be reduced.

  In the present embodiment, when the thickness of the document bundle P detected by the document size detection sensors 25 to 27 is equal to or greater than the allowable number of sheets to be stacked, the display unit 48 issues an alarm. When the document bundle P is thicker than the allowable number of stacked sheets, the user can be urged to stop conveying the document, and the ADF 23 can be protected.

  Specifically, in the ADF 23, the allowable number of sheets to be stacked is determined. However, in reality, it is possible to place a document bundle P of an allowable number or more on the original table 24 from the viewpoint of user operability. If a large number of original bundles P are loaded and a large number of originals are transported, problems such as poor separation occur in the feeding belt 32 and reverse roller 33, or continuous operation exceeds the allowable number of originals. As a result, problems such as durability and temperature rise of the ADF 23 may occur.

  On the other hand, in the present embodiment, when the document bundle P is thicker than the allowable number of stacked sheets, an alarm can be generated to prompt the user to stop conveying the document, so that the ADF 23 is protected. be able to.

  Further, in the present embodiment, the calling means is constituted by a calling roller 31 that can be brought into contact with and retracted from the document bundle P, and the calling roller 31 includes a calling cam 126 and a stepping motor 101 that will be described later. By performing the lowering operation of the calling means by the stepping motor, it is possible to perform speed control with high accuracy by pulse count.

  In the present embodiment, when the calling roller 31 is controlled to be lowered, the pulse of the calling motor 101 until the calling roller 31 is lowered from the retracted position where the calling roller 31 is retracted from the document bundle P to the contact position where the calling roller 31 is in contact with the document bundle P. P is the number of pulses, P1 is the number of pulses of the calling motor 101 for accelerating the calling roller 31 to the maximum speed Vmax, and the calling motor 101 is used for decelerating the calling roller 31 from the steady state at the maximum speed to the contact position. Since the relationship of P> P1 + P2 is established when the number of pulses is P2, the calling roller 31 is always lowered at a constant speed by adjusting P1 and P2 to obtain the optimum steady state. It is possible to prevent a load fluctuation from occurring due to a sudden lowering of the calling roller 31, and the calling roller 31 contacts the document bundle P. Excessive impact can be further prevented from occurring when the.

  Further, in the present embodiment, the thickness of the document bundle P placed on the document table 24 based on the detection information of the document size detection sensors 25 to 27 and immediately after the uppermost document is separated from the document bundle P. Since the thickness of each separated document is calculated by comparing the thickness of the document bundle P, the same document size detection sensor 25 to detect the document size and the document thickness. 27, and the thickness of the original bundle P placed on the original table 24 and the thickness of the separated original P can be detected by the same original size detection sensors 25 to 27, and a number of detection means. Can be further prevented from increasing the manufacturing cost of the ADF 23.

Further, in the present embodiment, since the amount of abutment when the document is abutted against the pull-out roller pair 36 is changed according to the thickness of the document bundle P, the following effects can be obtained.
The abutting operation when the abutting amount is uniformly controlled regardless of the paper thickness of the document is performed for the purpose of preventing non-feeding of the document by the paper feed belt 32 and the pull-out roller pair 36 and skew correction. Increasing the value causes noise, document damage, and the like. Conversely, if the amount of bumping is small, the document will not be fed and skew will occur.

  Generally, thick documents tend to have a large slip, so if the amount of bumping is made uniform, the amount of bumping varies depending on the paper thickness and the skew amount changes. May occur.

  Further, if a dedicated sensor for detecting the paper thickness of the separated originals is provided in order to solve such a problem, a large number of sensors are needed to detect the thickness of the original bundle P and the separated originals. The manufacturing cost of the transfer device increases.

  Therefore, in the present embodiment, the thickness of the document bundle P placed on the document table 24 based on the detection information from the document size detection sensors 25 to 27 and immediately after the uppermost document is separated from the document bundle P. By comparing the thickness of the original bundle P with each other, the thickness of each separated original is calculated, and the amount of abutment by the pull-out roller pair 36 is changed according to the paper thickness of the separated original. It is possible to perform optimal skew correction according to the thickness of the separated original and to prevent the original from being unfed.

  Further, in the present embodiment, a plurality of document size detection sensors 25 to 27 are provided so as to be separated along the document conveyance direction, the separation distance S between the separation sensor 51 and the stopper claw 28, and the document size detection sensors 25 to 25. Since the relationship between the separation distances S1 and S2 of S27 is S> Sn, the separation distance S between the document table 24 and the stopper member is larger than the separation distances S1 and S2 of the document size detection sensors 25 to 27. Before the leading edge of the document reaches the document size detection sensors 25 to 27, the trailing edge of the document can always pass through any one of the document size detection sensors 25 to 27.

  Therefore, the document size detection sensors 25 to 27 reliably detect the thickness of the document bundle P placed on the document table 24 and the thickness of the document bundle P immediately after the uppermost document is separated from the document bundle P. Then, they can be compared.

  Further, in the present embodiment, the amount of abutment when the document is abutted against the reading entrance roller pair 37 is changed according to the thickness of the document bundle P. Therefore, immediately before the reading position 80 where the image of the document is read. It is possible to perform optimal skew correction according to the thickness of the separated original and to prevent the original from being unfed.

  In the present embodiment, since the discharge speed of the document discharged to the discharge tray 43 is varied according to the thickness of the separated document, the stack of the documents discharged to the discharge tray 43 is changed. Can be improved.

  Specifically, when a document is discharged to the discharge tray 43 at a constant speed regardless of the paper thickness, depending on the discharge speed, thin paper or the like that is less stiff depends on the frame of the document transport path. It may not be able to be completely discharged due to being caught in the

  If the discharge speed is increased as a countermeasure, a new problem that a large-size document such as A3 falls from the discharge tray 43 may occur. Therefore, even if a discharge speed that can be satisfactorily set in the discharge tray 43 can be set for a large-size original of thin paper or thick paper, the stacking property is obtained when originals having different paper thicknesses are stacked on the discharge tray 43. The problem that becomes very bad occurs.

  In this embodiment, by changing the discharge speed of the document discharged to the discharge tray 43 according to the paper thickness of the separated document, the trailing edge of the thin paper that is weak is used as the frame of the document transport path. Documents with different paper thicknesses can be satisfactorily stacked on the paper discharge tray 43 by preventing them from being caught or preventing large-size originals such as A3 from dropping from the paper discharge tray 43. .

Further, in the present embodiment, the conditions for performing the jam determination are made different according to the paper thickness of the document being conveyed, so the following effects can be obtained.
In general, the determination criterion for a jam is set so that the conveyance distance is long in consideration of the slip of the original. However, the original is conveyed via a plurality of driving sources such as a paper feed motor 102, a reading motor 103, and a reverse motor 104. If some of the driving sources step out and force is applied to force the conveyance, the thin paper with small slip will be forcibly conveyed over a long distance before the jam is judged. The document will be damaged.

  In this embodiment, by changing the conditions for performing jam determination according to the paper thickness of the document being conveyed, optimal jam determination according to the paper thickness is performed to prevent the document from being damaged. can do.

  In the present embodiment, the present invention is applied to the ADF 23 that transports a document. However, the present invention may be applied to a sheet transport apparatus that transports a recording medium such as a transfer sheet as a sheet. For example, the present invention is applied to a sheet conveying apparatus including storage cassettes 91 to 95 storing transfer sheets S1 to S5 provided in a main body 21a, call rollers 91a to 95a, relay roller pairs 96 and 97, registration roller pairs 98, and the like. Then, the transfer paper may be conveyed to a processing position between the photosensitive drum 83 and the transfer belt 87.

  As described above, the automatic paper conveyance device, the image reading device, and the image forming device according to the present invention do not require a dedicated sensor for detecting the paper thickness, and are excessive when the calling unit contacts the paper bundle. A low-cost automatic paper conveyance device, an image reading device, and an image forming device that can prevent occurrence of a shock, can prevent noise, and can protect a calling unit and a paper bundle. From an image reading apparatus such as a copying machine, a facsimile machine, a scanner apparatus, and a multifunction machine, or an image forming apparatus such as a copying machine, a facsimile machine, a printer apparatus, and a multifunction machine. It is useful as an automatic paper conveyance device, an image reading device, an image forming device, and the like that separate the uppermost paper and convey it to a processing position.

1 is a diagram showing an embodiment of an image forming apparatus including an automatic paper conveyance device and an image reading device according to the present invention, and is a schematic configuration diagram of a copying machine as the image forming device 1 is a schematic configuration diagram of an automatic paper conveyance device according to an embodiment. 1 is a block diagram of a control system of an automatic document feeder according to an embodiment. The figure which shows the relationship between the pulse of the motor of one Embodiment, and the drive speed of a motor The figure which shows the drive system from the calling motor of one Embodiment The figure which shows the drive system from the paper feed motor of one Embodiment The figure which shows a drive system from the reading motor of one Embodiment The figure which shows the drive system from the reversing motor of one embodiment Flow chart of transport control according to one embodiment Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control when reading of a document according to one embodiment is started Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG. Flowchart of conveyance control following FIG.

Explanation of symbols

21 Copying machine (image forming device)
23 ADF (automatic paper feeder)
24 Document table (paper placement table)
25-27 Document size detection sensor (paper size detection means)
28 Stopper claw (stopper member)
31 Calling roller (calling means)
32 Paper feed belt (Separation / paper feed means)
33 Reverse roller (separation / paper feeding means)
36 Pull-out roller pair (rotating member, first skew correcting means)
37 Reading entrance roller pair (rotating member, second skew correcting means)
43 Output tray 48 Display (alarm means)
51 Separation sensor (separation sheet detection means)
81 Image Reading Device 83 Photosensitive Drum (Image Forming Unit)
86 Developing device (image forming means)
87 Transfer belt (image forming means)
88 Cleaning device (image forming means)
100 controller (alarm means, descending state control means, separation sheet thickness calculation means, discharge speed variable means, jam determination means)
101 Calling motor (elevating member)
103 Reading motor (paper discharge speed variable means)
126 Calling cam (elevating member)
P Document bundle (paper bundle)
S1 to S5 Transfer paper (recording medium)

Claims (10)

A paper platform on which a stack of paper is placed;
The upper sheet of the sheet bundle is provided so as to be movable up and down between a position contacting the sheet bundle placed on the sheet placing table and a position retracting from the sheet bundle. Calling means for feeding
Separating / feeding means for separating the uppermost sheet from the upper sheet bundle fed by the calling means and transporting it toward the processing position;
In an automatic paper conveyance device comprising a paper size detection means for detecting a conveyance direction length of a paper bundle placed on the paper placement table,
The paper size detecting means comprises a sensor for detecting a thickness of a paper bundle placed on the paper placing table;
A lowering state control means for performing a lowering control of the calling means based on the thickness information of the sheet bundle detected by the paper size detecting means ;
Based on the detection information of the paper size detecting means, the thickness of the paper bundle placed on the paper placement table is compared with the thickness of the paper bundle immediately after the topmost paper is separated from the paper bundle. Separating sheet thickness calculating means for calculating the thickness per sheet of the separated sheets,
A first skew correction unit provided with a pair of rotating members provided on the downstream side in the sheet conveyance direction with respect to the separating / feeding unit, and a leading end of the separated sheet abutting on a nip portion;
Provided downstream of the first skew correction means in the paper conveyance direction and upstream of the processing position in the paper conveyance direction, at the leading edge of the separation paper immediately before being conveyed to the processing position A second skew correction means comprising a pair of rotating members to be abutted,
In the first skew correction unit and the second skew correction unit, the amount of abutment on each of the pair of rotating members is changed according to the sheet thickness of the separation sheet calculated by the separation sheet thickness calculation unit. automatic sheet conveying apparatus characterized in that it is.   2. The automatic paper conveyance device according to claim 1, further comprising an alarm unit that issues an alarm when the thickness of the sheet bundle detected by the sheet size detection unit is greater than or equal to the allowable number of stacked sheets. .   2. The calling device according to claim 1, wherein the calling unit includes a rotating member that can be brought into contact with and retracted from the sheet bundle, and a lifting member that lifts and lowers the rotating member, and the lifting member includes a stepping motor. 2. The automatic paper conveyance device according to 2.   When the lowering control means lowers the calling means, the number of pulses of the stepping motor until the calling means is lowered from the retracted position to the contact position is increased to P, and the calling means is accelerated to the maximum speed. P1 represents the number of pulses of the stepping motor for causing P1 and P2 represents the number of pulses of the stepping motor for decelerating the calling means until it moves from the steady state at the maximum speed to the contact position. 4. The automatic paper conveyance device according to claim 1, wherein a relationship of> P1 + P2 is established. A plurality of the paper size detection means are provided so as to be separated along the transport direction of the paper,
A stopper member provided on the downstream side in the sheet conveying direction with respect to the sheet mounting table, and having a leading end of the sheet bundle abutted against the stopper member;
A separation sheet detection unit that is provided between the stopper member and the first skew correction unit and detects a separation sheet;
5. The relationship between the separation distance S between the separation sheet detection means and the stopper member and the separation distance Sn between the sheet size detection means is S> Sn . The automatic paper conveyance device according to item 1. A paper discharge tray for discharging the paper transported from the processing position, and a paper discharge speed variable means for changing a paper discharge speed of the paper discharged to the paper discharge tray according to the thickness of the separation paper. automatic paper conveying device according to any one of claims 1 to 5, characterized in that it has. The automatic paper conveyance according to any one of claims 1 to 6, further comprising a jam determination unit that changes a condition for performing a jam determination according to a paper thickness of the paper being conveyed. apparatus. Provided with a image reading means for reading an image of the sheet in the processing position, the image reading apparatus characterized by having an automatic paper conveying device according to any one of請Motomeko 1 to claim 7. An image forming apparatus comprising: an image forming unit that forms an image on the sheet at the processing position; and the automatic sheet conveying device according to claim 1. An image forming apparatus comprising: an image forming unit that forms an image on a recording medium; and the image reading apparatus according to claim 8.

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