JP2010052936A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of reducing a load on a paper jam-treating operation when a paper jam occurs. <P>SOLUTION: This image forming device includes a control part which determines whether sheet clogging occurs or not on the basis of the results of sheet detection by a sheet detection part. The control part determines the position of the occurrence of sheet clogging by the sheet detection part, and calculates a conveying path through which sheets can be fed to a paper discharge part without passing through the position. The control part also provides a path change instruction according to the calculated conveying path to a path change part to convey and discharge the sheets. Therefore, it is prevented that the sheets are further conveyed to the paper discharge part where paper jam occurs and the paper jam is further enhanced. Also, the sheets whose printing is interrupted due to the occurrence of paper jam can be taken out to the outside of the device without requiring paper jam treatment operations such as opening and closing operations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of discharging a sheet staying on a conveyance path when a sheet jam occurs in the image forming apparatus.

  In image forming apparatuses such as copiers, printers, and fax machines, a powder developer (hereinafter referred to as “toner”) is used, and an electrostatic latent image formed on an image carrier such as a photosensitive drum is formed with toner. Generally, the toner image is visualized and the toner image is transferred onto a recording medium (hereinafter referred to as “sheet”), and then a fixing process is performed.

  The image forming apparatus as described above conveys a sheet stored in a paper feed cassette to an image forming unit along a sheet conveyance path, and prints a toner image on the sheet by the image forming unit. Then, the sheet on which the toner image is printed is conveyed to the fixing unit, and the sheet on which the toner image is fixed by the fixing unit is discharged onto the discharge tray by the sheet discharge unit.

  In such an image forming apparatus, a sheet is curled in a sheet conveyance path or a sheet discharge unit or the like due to a cause that the sheet is curled or the size and thickness of the sheet to be used are not necessarily constant (hereinafter, referred to as “sheet jam”). "Jam") may occur. Various techniques have been developed for facilitating the processing for eliminating the jam (hereinafter referred to as “jam processing”).

In relation to the above, Patent Document 1 discloses an image forming apparatus that can easily handle a jam generated in a sheet discharge unit or a post-processing unit during printing. When a jam occurs, the image forming apparatus collects all the sheets sent from the sheet supply unit to the sheet conveyance path after the jammed sheet on the sheet support unit of the duplex printing unit. Thereby, the double-sided printing unit can be pulled out from the apparatus main body, and the sheets collected on the sheet support portion can be taken out collectively.
JP 2004-175482 A

  However, the image forming apparatus disclosed in Patent Document 1 is limited to a case where a double-sided printing unit is provided and a structure in which a plurality of sheets can be stored in the double-sided printing unit. Further, at the time of jam processing, in addition to the work of removing the jammed sheet by opening and closing the cover, it is necessary to take out the staying sheet, and in Patent Document 1, it is necessary to remove the double-sided printing unit from the image forming apparatus. There was a problem.

  The present invention has been devised to solve the above-described problems, and an object thereof is to provide an image forming apparatus capable of reducing the burden of a jam processing operation when a jam occurs.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a conveyance unit that conveys a sheet, a path changing unit that switches a sheet conveyance direction at a branch position of a conveyance path included in the conveyance unit, In an image forming apparatus including a sheet detection unit that detects whether a sheet is present in the conveyance path using a sensor, and a plurality of paper discharge units connected to the conveyance path, a sheet detection result by the sheet detection unit Whether or not a sheet jam has occurred is determined, and if it is determined that a sheet jam has occurred, the sheet detection unit determines the occurrence position of the sheet jam and passes through the occurrence position. Without calculating the conveyance path that can convey the sheet to the paper discharge unit, giving a path change instruction based on the calculated conveyance path to the path change unit, and instructing the conveyance unit to convey the sheet Characterized by comprising a that controller.

  According to this, the image forming apparatus of the present invention exists on the conveyance path, a conveyance unit that conveys the sheet, a path change unit that switches the conveyance direction of the sheet at the branch position of the conveyance path included in the conveyance unit, and the conveyance path. A sheet detection unit for detecting a sheet and a plurality of paper discharge units connected to the conveyance path are provided. In addition, a control unit is provided that determines whether or not a sheet jam has occurred based on a sheet detection result by the sheet detection unit. When the sheet jam occurs, the control unit determines the position where the sheet jam occurs, and calculates a conveyance path through which the sheet can be conveyed to the sheet discharge unit without passing through the occurrence position. A route change instruction based on the calculated conveyance route is given to the route change unit, and the sheet is conveyed and discharged. For this reason, since the staying sheet in which the printing process is interrupted due to the occurrence of a jam is automatically discharged, the burden on the user in the jam handling operation can be reduced.

  In order to achieve the above object, in the image forming apparatus of the present invention, when the control unit detects occurrence of a sheet jam, the generation position is the first condition that the generation position is the paper discharge unit, and the generation position Is not the branch position, and the third condition is that the sheet existing upstream of the branch position is detected by the sheet detection unit, and all of the first condition to the third condition are satisfied. When the condition is satisfied, a conveyance path that can convey the sheet upstream from the branch position to the sheet discharge unit where no sheet jam has occurred is calculated, and a path change instruction based on the calculated conveyance path Is provided to the path changing unit to instruct the conveyance unit to convey the sheet.

  According to this, when the occurrence of the sheet jam is detected, the control unit included in the image forming apparatus according to the present invention assumes that the generation position is a paper discharge unit and that the generation position is not a branch position. The second condition is that the sheet existing upstream of the branch position is detected by the sheet detection unit. Then, when all of the first condition to the third condition are satisfied, a conveyance path capable of conveying the sheet upstream from the branch position to the sheet discharge unit where no sheet jam has occurred is calculated. Then, a route change instruction based on the calculated conveyance route is given to the route change unit, and the sheet is conveyed. As a result, since the sheet is changed and the sheet is discharged only when the sheet discharge path can be established, the path is changed even though the discharge path cannot be established, and the jam is further deteriorated. It can be avoided.

  In order to achieve the above object, the image forming apparatus of the present invention includes a post-processing device that is connected to the paper discharge unit and performs post-processing of a sheet, and the control unit causes the post-processing device to generate a sheet jam. When the second condition and the third condition are satisfied, and if the condition is satisfied, the sheet upstream of the branch position is conveyed to the paper discharge unit to which the post-processing device is not connected. A possible conveyance route is calculated, a route change instruction based on the calculated conveyance route is given to the route change unit, and the conveyance unit is instructed to convey the sheet.

  According to this, the image forming apparatus of the present invention includes a post-processing device that performs post-processing on a sheet discharged from the discharge unit. Upon receiving the jam detection notification from the post-processing device, the control unit of the image forming apparatus determines whether the above-described second condition and third condition are satisfied using the sheet detection unit. In the case of satisfying, a conveyance path capable of conveying a sheet upstream from the branch position to a sheet discharge unit to which the post-processing apparatus is not connected is calculated. Then, a route change instruction based on the calculated conveyance route is given to the route change unit, and the sheet is conveyed. Thereby, when a jam occurs in the post-processing apparatus, it is possible to prevent the sheet from being further conveyed to the post-processing apparatus and the jam from deteriorating. In addition, since a sheet whose printing process or post-processing is interrupted due to the occurrence of a jam is automatically discharged to the outside of the apparatus, it is possible to reduce the burden on the user in the jam handling operation.

  In order to achieve the above object, in the image forming apparatus of the present invention, the control unit performs a charging process according to the number of discharged sheets, and the conveyance direction is changed by the path changing unit when a sheet jam is detected. The sheet is excluded from the billing process.

  According to this, the control unit provided in the image forming apparatus of the present invention charges according to the number of discharged sheets. However, when a jam is detected, the path is changed, and the staying sheets are discharged, charging for these sheets is not performed. For this reason, unnecessary billing can be avoided for a sheet whose printing has been interrupted.

  In order to achieve the above object, the image forming apparatus according to the present invention is configured such that when the control unit instructs the path changing unit to switch the transport direction when a sheet jam is detected, the transport unit and the path changing unit. In contrast, sheet inversion processing and switchback processing are prohibited.

  According to this, the control unit provided in the image forming apparatus of the present invention does not perform the sheet reversing process and the switchback process on the conveying unit and the path changing unit when the path is changed at the time of jam detection. Instruct. This is because the inversion process and the switchback process are effective only during normal operation, and are unnecessary processes for discharging the sheet when an error occurs. By reducing unnecessary processing in this way, the sheets staying on the conveyance path can be discharged out of the apparatus more quickly.

  According to the present invention, when a jam occurs, the staying sheet existing on the sheet conveyance path can be automatically discharged. For this reason, when a jam occurs, the user only needs to remove the sheet that caused the paper jam. Thus, the user's work burden in the jam handling work can be reduced.

  Further, according to the present invention, only when the sheet does not exist at the branch position and a sheet discharge path avoiding the jam occurrence position can be established, the path is changed and the sheet is discharged. Thereby, it is possible to prevent the route from being changed erroneously and causing a serious failure due to a jam.

  Further, according to the present invention, since the charging process is not performed when a jam occurs, it is possible to prevent unnecessary charging from occurring on the sheet discharged by the error process. Further, when the jam occurs, the sheet reversing process and the switchback process are not performed, so that the staying sheet discharging process time can be shortened. Thereby, the return from the error state to the normal state can be performed more quickly.

  An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In addition, embodiment shown here is an example and this invention is not limited to embodiment shown here.

<1. Schematic configuration of the device>
Here, an outline of the copying machine 1 (= image forming apparatus) according to an embodiment of the present invention and the post-processing apparatus 4 which is an optional apparatus connected to the copying machine 1 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view of the schematic configuration of the copy machine 1 and the post-processing device 4 as seen from the front.

  As shown in FIG. 2, the copier 1 includes a main body 3, an image reading device 2 disposed above the main body 3, and a post-processing device 4 disposed on a side surface of the main body 3. . Here, first, a schematic configuration of the main body 3 will be described.

  The main body unit 3 includes a sheet supply unit 20, a sheet conveyance path 24 (= conveyance unit, conveyance path), an image forming unit 30, a fixing device 40, a sheet discharge unit 43 (= sheet discharge unit), and the like. Yes. A paper discharge space is provided at a position above the center of the main body 3. Therefore, these configurations will be described along the conveyance path of the sheet S. In FIG. 2, the conveyance path of the sheet S in the main body 3 is shown by a solid line arrow.

  First, the sheet supply unit 20 is for sending a sheet S such as a copy sheet or an OHP sheet toward the image forming unit 30, and is provided at the lowermost part of the main body unit 3. The sheet supply unit 20 includes a sheet feeding cassette 21, a sheet placing plate 22, and a sheet feeding roller 23.

  The sheet feeding cassette 21 is for stacking and storing a plurality of sheets S, is box-shaped and has an open upper surface, and can be pulled out and detached from the main body 3 for sheet supply. A sheet placement plate 22 on which a plurality of sheets S are placed is provided in the paper feed cassette 21. In addition, a paper feed roller 23 is provided on the upper part of the paper feed cassette 21 on the downstream side in the sheet conveying direction (upper left position in FIG. 2).

  The sheet conveyance path 24 is for conveying the sheet S in the copying machine 1. The sheet conveyance path 24 is branched at a plurality of branch positions. In the example of FIG. 2, there are four sheet conveyance paths 24a to 24d. The sheet conveyance path 24 a conveys the sheet S from the sheet supply unit 20 to the sheet discharge unit 43 through the image forming unit 30 and the fixing device 40. The sheet conveyance path 24 b branches from the sheet conveyance path 24 a downstream of the fixing device 40. The sheet conveyance path 24b conveys the sheet S in the direction of the post-processing device 4 (described later).

  The sheet conveyance path 24 c branches from the sheet conveyance path 24 b downstream of the conveyance roller pair 27 and conveys the sheet S to the post-processing device 4. The sheet conveyance path 24 d branches from the sheet conveyance path 24 b downstream of the conveyance roller pair 27 and conveys the sheet S to the image forming unit 30. The sheet conveyance path 24 includes a conveyance roller pair 25 (= conveyance unit) and a plurality of guide plates (not shown) for guiding the sheet S.

  A registration roller pair 26 is provided in front of the image forming unit 30 on the upstream side in the sheet conveyance direction. The registration roller pair 26 temporarily stops the conveyed sheet S, and sends the sheet S toward the image forming unit 30 at a predetermined timing and speed so that the toner image is transferred at an appropriate position of the sheet S.

  The image forming unit 30 forms a toner image of an image to be formed based on a document read by the image reading device 2 or image data input to the copier 1 and transfers the toner image to the sheet S. In the example of FIG. 2, it is arranged at a position slightly to the left of the center of the main body 3. The image forming unit 30 includes a photosensitive drum 31 as an image carrier, a charging device 32, an exposure device 33, a developing device 34, a transfer roller 36, a cleaning device 37, and the like.

  The photosensitive drum 31 is disposed at a substantially central position of the image forming unit 30 and is rotationally driven in a predetermined direction (clockwise in FIG. 2) by a driving device (not shown). For example, the photosensitive drum 31 is configured to have a positively charged OPC or amorphous silicon photosensitive layer on the outer peripheral surface of an aluminum drum. Then, after an electrostatic latent image is formed on the peripheral surface of the photoconductive drum 31, toner is supplied to form a toner image on the peripheral surface of the photoconductive drum 31.

  In the example of FIG. 2, the charging device 32 is disposed facing diagonally upward to the right of the photosensitive drum 31, and charges the peripheral surface of the photosensitive drum 31 with a predetermined potential. In this embodiment, a corona charger is used as the charging device 32. However, as long as the surface of the photosensitive drum 31 can be charged to a predetermined potential, the charging device 32 using a charging roller or a brush may be used.

  In the example of FIG. 2, the exposure device 33 is disposed on the right side of the photosensitive drum 31 and the charging device 32. The exposure device 33 irradiates the photosensitive drum 31 with light on the circumferential surface of the uniformly charged photosensitive drum 31 based on the image data of the image to be formed, and scans the circumferential surface of the photosensitive drum 31. , Expose. Thereby, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 31.

  In the example of FIG. 2, the developing device 34 is provided below the photosensitive drum 31, accommodates toner, charges the toner to a predetermined potential, and forms the toner on the peripheral surface of the photosensitive drum 31. Supply toward the electrostatic latent image. A developing roller 35 is provided in the developing device 34 at a position facing the photosensitive drum 31 with a predetermined gap for supplying toner. The developing roller 35 rotates in a predetermined direction while carrying toner on the peripheral surface. When a predetermined voltage is applied to the developing roller 35, the toner flies toward the image carrier, and the electrostatic latent image is developed.

  In the example of FIG. 2, the transfer roller 36 is supported so as to be rotatable diagonally to the left of the photosensitive drum 31. The transfer roller 36 is for transferring the toner image formed on the photosensitive drum 31 to the sheet S, and abuts on the photosensitive drum 31 to form a nip for transfer. When the sheet S enters the nip, a voltage having a polarity opposite to the charging polarity of the photosensitive drum 31 is applied to the transfer roller 36, and the toner image is transferred to the sheet S.

  The cleaning device 37 is disposed above the photosensitive drum 31 in the example of FIG. The cleaning device 37 removes and collects residual toner, dust, and the like on the peripheral surface of the photosensitive drum 31. In this embodiment, a blade formed to extend in the axial direction of the photosensitive drum 31 is brought into contact with the photosensitive drum 31. However, as long as the photosensitive drum 31 can be cleaned, a roller may be used, or a blade and a roller may be used in combination.

  The fixing device 40 is for pressurizing and heating the toner image transferred to the sheet S to melt the toner and fix the toner image on the sheet S. The fixing device 40 includes a heating roller 41, a pressure roller 42, and the like. A heating element (not shown) is built in the heating roller 41. The heating element warms the heating roller 41 to a temperature at which the toner can be melted. The pressure roller 42 is formed using an elastic material such as silicon rubber.

  The heating roller 41 and the pressure roller 42 are pressed to form a nip. The sheet S on which the toner image is transferred enters the nip, thereby fixing the toner to the sheet S. The sheet S that has been fixed is conveyed to the discharge unit 43. The paper is discharged by a discharge roller pair 45 toward a discharge tray 44 provided on the side of the discharge portion 43.

  Next, a schematic configuration of the image reading apparatus 2 will be described.

  As shown in FIG. 2, the image reading apparatus 2 according to the present embodiment includes a box-shaped casing 110 provided on the upper part of the main body 3. A document placement surface 111 is disposed on the upper surface of the image reading apparatus 2.

  The document placement surface 111 is a surface on which the document is placed with the opening / closing unit 130 lifted and the document to be read facing downward. Reading a document on the document placement surface 111 is performed by placing the reading unit 120 below the document placement surface 111 and moving it horizontally from the home position to the right in FIG. 2 by the wire 112 and the winding drum 113. . The document placement surface 111 is formed of a rectangular plate-like member having a certain thickness made of a light-transmitting material such as glass.

  As shown in FIG. 2, a wire 112, a winding drum 113, a lens 114, an image sensor 115, a reading unit 120, and the like are disposed in the housing 110 of the image reading device 2. The reading unit 120 includes a first reading unit 121 and a second reading unit 122. Note that the first reading unit 121 is disposed above and the second reading unit 122 is disposed below.

  A wire 112 is attached to the first reading unit 121 and the second reading unit 122, the other end of the wire 112 is connected to the winding drum 113, and the winding drum 113 rotates, so that the reading unit 120 is moved in the horizontal direction. Moving. The number of the wires 112 and the winding drum 113 is not limited to the number shown in the figure, and a configuration in which a plurality of wires 112 and the winding drum 113 are combined may be used.

  For example, two wires 112 are wound around one winding drum 113, and the two wires 112 extend in different directions in the longitudinal direction (in FIG. 2, one is shown for simplicity). Only the book is shown) It is wound around a winding drum 113. Two (total of four) wires 112 on one side are appropriately bridged in the frame body by a plurality of pulleys (not shown), and the two wires 112 are connected to the first reading unit 121 and the second reading unit 122. When the forward / reverse rotation of the motor is controlled, the reading unit 120 can be moved freely along the scanning direction.

  A specific reading operation will be described. Light emitted from the light source of the reading unit 120 strikes the document 124 on the document placement surface 111, and the reflected light is reflected by the first mirror of the first reading unit 121 and the reading unit 120. Is reflected toward the upstream side in the scanning direction. A second mirror of the second reading unit 122 is disposed on the optical path, and the second mirror reflects light downward. Further, a third mirror is disposed on the optical path, and the third mirror reflects light toward the downstream side in the scanning direction.

  Thereafter, the reflected light is condensed on the lens 114, imaged by an image sensor 115 constituted by, for example, a CCD line sensor, etc., and converted into an electrical signal corresponding to the image density. Then, these scanning operations are successively performed from the home position where the reading unit 120 is first positioned to the document edge, whereby the entire document image is read and the document image is converted into data.

  Next, a schematic configuration of the post-processing device 4 will be described.

  As shown in FIG. 2, the post-processing device 4 in this embodiment is provided on the side surface of the main body 3. Then, the sheet S is received from the image forming apparatus 1 through the sheet conveyance path 49 connected to the sheet conveyance path 24 c of the image reading apparatus 2, and post-processing is performed on the sheet S.

  The post-processing device 4 includes a punch unit 52 provided near the uppermost stream of the sheet conveyance path 49 in the post-processing device 4 and an intermediate roller pair 53 provided downstream of the punch unit 52 in the sheet conveyance direction. . Further, in order to receive the sheet S discharged from the post-processing device 4, a main discharge tray 54 provided on the left side surface portion of the post-processing device 4, a sub-discharge tray 55 provided on the main discharge tray 54, and an intermediate roller pair 53. A retracting drum 56 for temporarily retracting the sheet S conveyed from the sheet, a staple processing unit 57 provided in the center of the apparatus for stacking the sheets S introduced into the post-processing device 4 and performing a stapling process, a staple processing unit 57, and the like.

  The punch unit 52 performs a punching process on the sheet S. The intermediate roller pair 53 is for conveying the sheet S toward the retracting drum 56, the main discharge tray 54, the sub discharge tray 55, the staple processing unit 57, and the like.

  The main discharge tray 54 is for receiving a sheet bundle which is stapled by the staple processing unit 57 and discharged. The sub discharge tray 55 is for receiving the sheet S discharged without being processed by the post-processing apparatus 4 or the sheet S subjected to only the punching process.

  When the stapling process is performed continuously on a plurality of sheet bundles, the retracting drum 56 is configured such that the first sheet of the next sheet bundle is placed on the drum surface while the previous sheet bundle is being stapled by the staple processing unit 57. Wrap around and wait. The operation of the retracting drum 56 eliminates the need to temporarily stop the discharge of the sheet S from the image forming apparatus 3 during the stapling process.

  The post-processing device 4 is provided with a plurality of sorts for sorting the sheet S that has passed through the punch unit 52 to the staple processing unit 57, the retracting drum 56, the main discharge tray 54, the sub discharge tray 55, and the like. The guide 59 is rotatably held.

  The staple processing unit 57 performs stacking processing to stack a plurality of sheets S, staples the front end of the stacked sheet bundle with staples, and staples at the center in the longitudinal direction of the sheet bundle along the short direction. Various stapling processes such as center binding, which are bound with the.

  Below the staple processing unit 57, a middle folding processing unit 58 for performing a folding process along the staples at the center of the bundle of sheets bound at the center is arranged. When the folding process is selected, the sheet bundle subjected to center binding is conveyed to the middle folding processing unit 58, and the folded booklet sheet bundle is placed at the lower part of one side surface of the post-processing device 4. It is discharged to the provided booklet tray 58a. When the bending process is not selected, the sheet bundle subjected to the center binding is conveyed to the discharge roller pair and discharged to the main discharge tray 54.

<2. Conveying path configuration>
Next, a schematic configuration of the conveyance path included in the copier 1 according to the embodiment of the present invention will be described with reference to the block diagram of FIG.

  FIG. 3 is a schematic cross-sectional view in which only the apparatus related to the sheet conveying process is extracted from the copying machine 1. In addition, about the apparatus already demonstrated in FIG. 2, description shall be abbreviate | omitted by adding the same code | symbol.

  At the branch position of the sheet conveyance path 24, the sheet conveyance direction can be switched by switching devices 81a and 81b (= path changing unit). In the example shown in FIG. 3, a switching device 81a is provided at a position where the sheet conveyance path 24a branches to the sheet conveyance path 24b. A switching device 81b is provided at a position where the sheet conveyance path 24b branches into the sheet conveyance path 24c and the sheet conveyance path 24d. For example, the switching device 81 is rotationally driven at the branching position and contacts the sheet S to thereby define the conveyance direction.

  A plurality of detection switches 82 (= sheet detection units) are provided in the sheet conveyance path 24 in order to detect the sheet S. In the example illustrated in FIG. 3, a detection switch 82 a is provided in the conveyance path downstream of the switching device 81 a and reaching the paper discharge unit 43. Further, a detection switch 82b and a detection switch 82c are provided downstream of the switching device 81a and in the sheet conveyance path 24b. A detection switch 82d is provided downstream of the switching device 81b and in the sheet conveyance path 24d. A detection switch 82 e is provided between the sheet supply unit 20 and the image forming unit 30. A detection switch 82f is provided between the image forming unit 30 and the switching device 81a.

  The detection switch 82 (82a to 82f) is used when the sheet S existing in the sheet conveying path 24 has reached the detection switch 82, when the detection switch 82 is passing, and when the sheet S does not exist. As a result, the output signal is switched. The control unit 90 (described later) can grasp the conveyance state and the number of sheets S existing in the sheet conveyance path 24 by monitoring the switching of the output signals.

  The detection switch 82 detects that the sheet S has passed through the detection switch 82 using, for example, an infrared sensor or a movement detection sensor. The detection switch 82 can also be used as a jam detection sensor for detecting a jam. For example, the control unit 90 monitors the time from when the sheet S starts to pass through the detection switch 82 to when the passage is completed.

  That is, when the detection switch 82 detects the arrival of the sheet and the passage of the sheet cannot be detected even after a predetermined time has elapsed (= the trailing edge of the sheet cannot be detected), the corresponding detection switch 82 causes a jam. Is determined to have occurred. Accordingly, for example, by providing the detection switch 82 in the vicinity of the paper discharge unit 43, it is possible to determine whether or not a jam has occurred in the paper discharge unit 43.

  Alternatively, it is possible to determine that a jam has occurred when a plurality of detection switches 82 are not used to detect the passage of the sheet S at the timing to be detected. For example, in the example shown in FIG. 3, when a sheet detected by the detection switch 82b has not been detected by the downstream detection switch 82c even after a predetermined time has elapsed, a jam occurs between the detection switch 82b and the detection switch 82c. Can be determined to have occurred.

  In the post-processing device 4, a detection switch 47 (= sheet detection unit) similar to the detection switch 82 is provided on the sheet conveyance path 49. Thereby, the sheet S sent via the sheet conveyance path 24c can be detected. Further, the post-processing device 4 can also detect a jam by the same method as the main unit 3. When a jam occurs in the post-processing device 4, a jam occurrence notification is sent from the post-processing device 4 to the main body 3. Receiving this, the main body unit 3 performs jam processing.

<3. About the configuration of the function section>
Next, the functional configuration of each device included in the copier 1 according to the embodiment of the present invention will be described with reference to the block diagram of FIG.

  As shown in the block diagram of FIG. 1, at least the copier 1 of the present embodiment includes at least a sheet supply unit 20, an image forming unit 30, a fixing device 40, a flash memory 71, a power supply unit 80, and a path changing unit included in the main body unit 3. 81, a detection switch 82, a control unit 90, a control unit 100 included in the image reading apparatus 2, a reading unit 120, an opening / closing unit 130, a detection switch 47 included in the post-processing device 4, a control unit 48, and a sheet conveyance path. 49. In addition, about the apparatus already demonstrated in FIG.2 and FIG.3, description is abbreviate | omitted here.

  The flash memory 71 is a recording device that temporarily records various data held by the main body 3. The flash memory 71 has a role of recording, for example, a control program used by the control unit 90 to control each device, processing data generated by various controls, setting data, user data, and the like.

  The power supply unit 80 supplies a drive voltage to each device included in the main body unit 3. The power supply unit 80 receives power from, for example, an external commercial power supply (not shown) or an internal battery (not shown), and performs conversion from AC to DC, rectification, voltage adjustment, and the like.

  The control unit 90 performs printing processing, sheet conveyance processing, and the like by controlling the operation of each device constituting the main body unit 3. The control unit 90 is composed of a plurality of microprocessors, for example. Similarly, the control unit 100 controls each device of the image reading device 2.

  The detection switch 47 provided in the post-processing device 4 is the same as the detection switch 82 described above. The control unit 48 performs various types of post-processing, such as punching processing and stapling processing, by controlling the operation of each device constituting the post-processing device 4. The control unit 48 also has a function of detecting a jam using the detection switch 47 and the like, and transmitting a jam occurrence notification to the control unit 90 when a jam is detected. The sheet conveyance path 49 conveys the sheet S received from the main body unit 3 and discharges the sheet S that has been post-processed.

<4. About jam processing>

  Here, jam processing of the copying machine 1 according to an embodiment of the present invention will be described with reference to the flowchart of FIG.

  The processing flow shown in FIG. 4 is started when the power of the copier 1 is turned on and processing related to sheet conveyance such as printing processing occurs. After the start of this process, the control unit 90 determines whether or not a jam has been detected in step S110. Note that jam detection is performed using the detection switch 82 or the like.

  In the jam detection, for example, it is estimated that the sheet S started to be conveyed by the sheet supply unit 20 does not pass the detection switch 82 even after a predetermined time has passed, or the presence of the sheet S that has started to pass is not detected. If the presence of the sheet S continues to be detected at a given time, it is determined that a jam has occurred, and the occurrence position is specified. Further, when a jam occurs in the post-processing device 4 and a jam occurrence notification sent from the control unit 48 is received, it is determined that a jam has occurred.

  If the occurrence of a jam is not detected, the process proceeds to step S110 again, and the jam occurrence is continuously monitored. When the occurrence of a jam is detected, the control unit 100 determines a member in which the occurrence of a jam is detected in step S120. As a result of the determination, if it is determined that the jam occurrence position is not the sheet discharge unit 43 or the post-processing device 4, it is difficult to establish a discharge path for the sheet S, which will be described later. Exit.

  When the jam occurrence position is the sheet discharge unit 43 or the post-processing device 4, the control unit 90 determines whether or not the sheet S exists near the branch position of the conveyance path, that is, in the vicinity of the switching device 81 in step S <b> 130. For example, based on the conveyance speed of the sheet S and the length of the sheet S, first, the time for the detection switch 82 to detect the sheet S (= time when the output signal is switched) is estimated. In the detection switch 82 in the vicinity of the branch position (for example, the detection switch 82b in FIG. 2), when the detection time of the sheet S exceeds the estimated time, it is determined that the sheet S exists in the vicinity of the switching device 81.

  Or the form using the some detection switch 82 (for example, 82a, 82b, 82f of FIG. 2) provided ranging over the branch position (for example, 81a of FIG. 2) may be sufficient. For example, when the sheet S detected by the detection switch 82f is not detected by either the detection switch 82a or the detection switch 82b even after a predetermined time has elapsed, a jam occurs in the vicinity of the switching device 81a. Can be determined.

  When the sheet S is present at the branch position, it is difficult to establish a conveyance path for the sheet S, which will be described later. When the sheet S does not exist at the branch position, the control unit 90 determines whether or not the sheet S exists upstream of each branch position in step S140. For example, the upstream sheet S is detected using a plurality of detection switches 82 (82b, 82c, 82e, and 82f in FIG. 2) existing upstream of the branch position.

  When there is no sheet S upstream of the branch position, it is not necessary to discharge the staying sheet S, so that a normal error process is performed and this process is terminated. When the sheet S exists upstream of the branch position, the control unit 90 calculates a path for conveying the corresponding sheet S to the sheet discharge unit 43. This path is calculated using error path information recorded in the flash memory 71, for example. In the error path information, for example, a position where a jam has occurred and a sheet conveyance path corresponding to the jam occurrence position are recorded in advance in association with each other. The control unit calculates a path for discharging the staying sheet S by referring to the detected jam occurrence position and emergency path information.

  Further, the control unit 90 instructs the route changing unit 81 to change the route so as to form the calculated route. As an example of the sheet S existing upstream of the branching position, for example, a sheet S that has not been printed, a sheet S that is in the middle of moving to the image forming unit 30 after being reversed for double-sided printing, and the like can be considered.

  The orientations of the switching device 81a and the switching device 81b are changed so that these sheets pass through the sheet transport path 24a shown in FIG. 3 and pass through the transport path where the detection switch 82a exists. At the same time, if there is a sheet S that is the target of the reversal process or the switchback process, the process is stopped and the discharge process is given the highest priority.

  Next, in step S160, the control unit 90 conveys the sheet S present in the sheet conveyance path 24. As a result, the sheet S present in the sheet conveyance path 24 is discharged to the discharge unit 43. At this time, the control unit 90 does not perform the charging process for the sheet S that is conveyed after the jam occurs and is discharged from the discharge unit 43.

  According to the present embodiment described above, when a jam occurs, it is not necessary to remove the staying sheet S by a predetermined user operation or a jam processing operation by opening and closing the main body 3. For example, the sheet S that is normally scheduled to be conveyed to the sheet conveyance path 24 b is also forcibly discharged from the sheet discharge unit 43. Thereby, since the sheet S staying inside the copying machine 1 can be easily taken out of the apparatus, it is possible to reduce the work burden on the user.

[Other embodiments]
The present invention has been described above with reference to preferred embodiments and examples. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea. be able to.

Therefore, the present invention can also be applied to the following embodiments.
(A) In the present embodiment, the copying machine 1 is described as an example of implementation of the present invention, but the same effect is achieved when the present invention is implemented in an image reading apparatus other than the above. For example, the present invention can be implemented in an image reading device such as a scanner device, a multifunction device, or a FAX device.

  (B) In this embodiment, the processing related to the sheet conveying operation of the present invention is realized by executing a program on an arithmetic processing unit such as a microprocessor, but each processing is performed by a plurality of circuits. It may be a form.

  (C) In the present embodiment, the destination where the sheet S is forcibly discharged when a jam occurs is described by taking the sheet discharge portion 43 as an example, but it may be discharged to other discharge destinations. For example, a configuration in which a plurality of sheet discharge units 43 are provided, the control unit 90 determines the sheet discharge unit 43 closest to the staying sheet S, and the conveyance path is switched based on the determination result. Thereby, the sheet S can be discharged more quickly. Or conversely, the forced discharge destination at the time of jam occurrence may be fixed.

  (D) In this embodiment, the sheet S discharged by the jam processing is not charged, but other processing, for example, update of the number of printed sheets used for managing the life of the apparatus is updated. Etc. are desirable. Alternatively, the management information may be configured so that the user can set in advance whether to count the forcibly discharged sheets S.

  (E) In the present embodiment, the process after the sheet S is forcibly discharged by the jam process is not particularly defined. However, for example, an error display is performed and the process shifts to a state of waiting for a user instruction. Alternatively, the interrupted printing process may be restarted using the sheet conveyance path and the sheet discharge unit in which no jam has occurred.

  (F) In the present embodiment, the destination for forcibly discharging the sheet S by the jam processing is described by taking the paper discharge unit 43 as an example, but the form discharged to the post-processing device 4 may be used. In this case, all the various post-processing in the post-processing apparatus 4 are stopped, and only the sheet S is conveyed and discharged.

2 is a block diagram illustrating a functional configuration of the image forming apparatus of the present invention. FIG. 1 is a cross-sectional view of a schematic configuration of an image forming apparatus of the present invention viewed from the front. FIG. 3 is a schematic cross-sectional view illustrating a sheet conveyance path of the image reading apparatus of the present invention. It is a flowchart which shows the processing flow of the jam processing of this invention.

Explanation of symbols

1 Copy machine (image forming device)
2 Image reading device 4 Post-processing device 24 Sheet conveyance path (conveyance unit, conveyance path)
25 Conveying roller pair (conveying section)
26 Registration roller pair (conveyance unit)
27-29 Conveying roller pair (conveying unit)
43 Sheet discharge unit (paper output unit)
47 Detection switch (sheet detector)
48 Control unit 49 Sheet conveyance path (conveyance path)
81 Switching device (route changing unit)
82 Detection switch (sheet detector)
90 Control unit

Claims (5)

Detecting whether a sheet exists in the conveyance path using a plurality of sensors, a conveyance unit that conveys the sheet, a path changing unit that switches the conveyance direction of the sheet at a branch position of the conveyance path included in the conveyance unit, and a plurality of sensors In an image forming apparatus including a sheet detection unit that performs a plurality of sheet discharge units connected to the conveyance path,
It is determined whether or not a sheet jam has occurred based on a sheet detection result by the sheet detection unit, and when it is determined that a sheet jam has occurred, the sheet detection unit determines the occurrence position of the sheet jam. And calculating a transport path through which the sheet can be transported to the paper discharge unit without passing through the generation position, giving a path change instruction based on the calculated transport path to the path change unit, and transporting the sheet An image forming apparatus comprising a control unit that instructs a conveyance unit. When the control unit detects occurrence of sheet jamming, the first condition is that the generation position is the paper discharge unit, and the second condition is that the generation position is not the branch position. It is determined that the sheet existing upstream of the position is detected by the sheet detection unit as a third condition, and whether or not all the third conditions are satisfied from the first condition. A transport path capable of transporting the sheet to the paper discharge section where no sheet jam has occurred is calculated, a path change instruction based on the calculated transport path is given to the path change section, and the transport of the sheet is performed in the transport section The image forming apparatus according to claim 1, wherein: A post-processing device connected to the paper discharge unit for post-processing the sheet;
The control unit determines whether the second condition and the third condition are satisfied when the post-processing device detects occurrence of a sheet jam, and if the second condition and the third condition are satisfied, A transport path that can be transported to the paper discharge unit to which a post-processing device is not connected is calculated, a path change instruction based on the calculated transport path is given to the path change section, and a sheet transport is instructed to the transport section The image forming apparatus according to claim 2, wherein: The control unit performs a charging process according to the number of discharged sheets, and excludes a sheet whose conveyance direction has been changed by the path changing unit when a sheet jam is detected, from the charging process. The image forming apparatus according to claim 1. When the control unit instructs the path changing unit to switch the conveyance direction when a sheet jam is detected, the control unit prohibits the sheet reversing process and the switchback process for the conveying unit and the path changing unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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