JP2013136425A - Sheet feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate jam treating operation when stopping sheet feeding and conveying in a sheet feeder while properly doing retry in the range not becoming complicated control and preventing the stop of the sheet feeding and the conveying by non-sheet feeding jam.SOLUTION: A sheet feeder includes a sheet feeding conveying passage, a sheet detecting body arranged in the conveying passage of the sheet feeding conveying passage and detecting the arrival and passage of fed sheets, and a sheet feeding rotating body stopping when non-sheet feed condition in which the sheet detecting body can not detect the arrival of sheets is detected within an allowable time determined in advance from starting the rotation, the sheet feeding rotating body carries out the retry in a retry interval not more than the interval obtained by dividing a discharge requiring time from the time when the first non-sheet feed condition till the time when the sheet fed directly before is discharged from the sheet conveying passage by the predetermined specific number of times, and the sheet feeding passage determines the generation of non-sheet feeding jam and stops the conveying when the arrival of the sheet can not be detected by the sheet detecting body even though the retry is carried out the specific number of times.

Description

  The present invention relates to a paper feeding device used for printing and an image forming apparatus (for example, a printer, a multifunction peripheral, a copier, a FAX device, etc.) provided with the paper feeding device.

  The image forming apparatus conveys the paper supplied from the paper feeding device and performs printing. Then, jamming (paper jam) may occur due to dirt or wear on the rotating member for paper feeding or conveyance, the state of the paper surface, the paper loading state, and the like. When the jam occurs, the paper is jammed in the paper feeding device or the conveyance path, or the paper is not properly sent out from the paper feeding device. After the image forming apparatus is automatically stopped due to various jams, the user performs jam processing such as removing a jammed sheet from the conveyance path or the sheet feeding device. Patent Document 1 discloses an invention that suppresses the occurrence of a jam and reduces the burden of a jam processing operation.

  Specifically, Japanese Patent Application Laid-Open No. 2004-228867 matches the paper writing unit, the means for designating the size of the stored paper, the paper feed roller that feeds the paper one by one from the paper feeding unit, and the image writing position. A function unit that once stops the transported paper by the registration roller, and then restarts operation, a sensor that detects that the paper has reached or passed the registration position, and the paper that is being transported by the sensor And a means for detecting the trailing edge of the second sheet. In the case of continuously feeding paper, after the first sheet is fed, the second sheet jam detection is not performed until the trailing edge of the sheet is detected. An apparatus is described. With this configuration, no paper-feed jam due to an incorrect size is prevented from occurring, and an operation for releasing the jam is attempted (see Patent Document 1: Claim 1, paragraph [0009], etc.).

JP 2002-211795 A

  For example, the paper feeding device supplies printing paper. In order to supply a sheet, the sheet feeding device is provided with a sheet feeding rotating body (for example, a sheet feeding roller or a sheet feeding roller) that feeds the sheet in contact with the sheet. Here, due to dirt and wear of the sheet feeding rotator, the condition of the sheet surface, the sheet loading condition in the sheet feeding device, etc., the sheet feeding rotator idles or the sheet is caught. As a result, the sheet may not be fed out (no sheet feeding state).

  When the paper is not fed, once the rotating body is stopped and the rotating body is rotated again (when retrying), the paper may be sent out. Therefore, conventionally, a retry is executed when it is not possible to detect the arrival of a sheet even after a lapse of a certain time from the start of sheet feeding by a sensor provided in the vicinity of the sheet feeding rotating body. When a paper arrival cannot be detected even after retrying a predetermined number of times (when the no-feed state cannot be resolved), it is assumed that a no-feed jam has occurred. Stop.

  Here, some paper feeders have a conveyance path (for example, a length of one sheet or more) inside. For example, an additional paper feeding device (optional paper feeding device) often has a conveyance path inside due to the attachment position with respect to the image forming apparatus. Conventionally, from the viewpoint of resuming printing as soon as possible, when it is determined that a non-paper jam has occurred, paper feeding and conveyance in the paper feeding device are immediately stopped. However, in a paper feed device having a transport path, a certain time is required from the start of paper feed until it can pass through the transport path in the paper feed device. Therefore, if the paper conveyance in the paper feeding device is immediately stopped due to the occurrence of a paper non-feed jam, the paper fed before the paper non-feed jam is stopped with the paper remaining in the conveyance path in the paper feeding device. .

  As described above, when a paper-feed jam having occurred in a paper feeding device has conventionally caused a paper-free jam to occur and the transport is stopped, the user checks the paper that caused the paper-free jam and removes the paper. There is also a problem that the operation of removing the sheet from the conveyance path in the apparatus must be performed, which is troublesome.

  Here, the image forming apparatus described in Patent Document 1 is provided with a sensor at the registration position, waits until the trailing edge of the preceding sheet passes through the sensor, and whether the sensor detects the arrival of the sheet before the timeout occurs. To detect the occurrence of no-feed jam (see Patent Document 1, paragraphs [0027] and [0031], FIG. 4 and the like). In other words, the arrival delay of the sheet at the registration position is detected as a no-feed jam. Therefore, there is a problem that the occurrence of a non-paper jam in the paper feeder cannot be detected immediately. Further, the image forming apparatus described in Patent Document 1 continues to rotate the sheet feeding rotating body until there is a delay in the arrival of the sheet at the registration position. Is not listed.

  In view of the above-described problems, the present invention avoids complicated feeding control and appropriately stops retrying to prevent paper feeding and conveyance from being stopped due to a paper feeding jam. It is an object of the present invention to simplify the jam handling operation when paper feeding and conveyance are stopped.

  In order to achieve the above object, a sheet feeding device according to a first aspect is connected to a conveyance path outside the sheet feeding device and conveys paper toward a conveyance path outside the sheet feeding device, and the sheet feeding device. A paper detector provided in the paper transport path for detecting the arrival and passage of the fed paper, and feeding the paper toward the paper feed transport path, and the paper detector starts rotating. Stops when a paper-free state that cannot detect the arrival of paper within a predetermined permissible time is detected, and stops rotation in the no-paper-feed state, waits for a retry interval, and performs a retry to rotate again The retry interval is from when the first non-feed state of the paper to be fed is detected until the paper fed immediately before is discharged from the paper feed path. The required time for discharging If the paper detection body cannot detect the arrival of paper even after performing the specified number of retries, a paper-feed jam has occurred, and no retry is performed. When the sheet detection body cannot detect the arrival of the sheet even after retrying the specified number of times, the sheet fed immediately before the sheet feeding path is discharged from the sheet feeding path. As a result, no paper feeding jam occurred and transportation was stopped.

  According to this configuration, the retry interval is a time required for discharging from the time when the first non-feed state of the paper to be fed is detected until the paper fed immediately before is ejected from the paper feed path. It is set to be equal to or less than the time obtained by dividing by a predetermined number of times, and when the paper detection body cannot detect the arrival of the paper even after retrying the predetermined number of times, as a paper-feed jam occurrence, If the paper detector is unable to detect the arrival of the paper even after retrying the specified number of times, the paper that has just been fed is discharged from the paper feed path. After that, it was decided to stop the conveyance as a paper-free jam occurred. As a result, when the paper feeding device stops operating due to the occurrence of a non-paper jam, the paper fed before the non-paper jam occurs does not remain in the paper feed path. Accordingly, it is possible to eliminate the operation of removing the paper from the paper feed conveyance path by the jam processing of the non-paper jam. Alternatively, it is only necessary to remove the paper on which the paper-feed jam has occurred (the paper that has been transported a little and remains in the paper feed path due to the paper-free jam), so the jam processing work is facilitated.

  In addition, retrying is performed a predetermined number of times or less before the paper fed immediately before is discharged from the paper feed conveyance path. As a result, it is possible to prevent unnecessary retrying from being performed while urging the paper feeding so that the paper feeding device does not stop due to the paper-free jam. In addition, the retry execution timing is determined based on an interval obtained by dividing the required discharge time until the paper fed immediately before the occurrence of no-feed jam is discharged from the paper feed path by a predetermined number of times. Therefore, the control is equivalent to simply extending the interval for performing the conventional retry, and the control is not complicated.

  According to a second aspect of the present invention, in the first aspect of the present invention, the rotation of the sheet feeding body waits for the retry interval obtained by dividing the required discharge time by the specified number of times after stopping the rotation. Later, the retry was performed.

  As a result, a retry is performed at a timing close to the discharge of the paper from the paper feeding device, and if the non-paper feeding state continues thereafter, the feeding operation and the paper feeding operation in the paper feeding device are stopped as occurrence of no paper jam. . Therefore, when a non-paper jam occurs, if the paper fed before the non-paper jam occurs is discharged from the paper feed device, the paper feed and transport in the paper feed device are quickly stopped.

  According to a third aspect of the present invention, in the first aspect of the present invention, the paper feeding rotating body is obtained by dividing the required discharge time by a number greater than the specified number of times after stopping the rotation. After waiting for the retry interval, the retry is performed.

  This ensures that a predetermined number of retries are made before the paper fed before the occurrence of no paper jam is ejected from the paper feed path, while the paper fed before the occurrence of no paper jam occurs. In accordance with the discharge from the paper feeding device, it is possible to quickly stop the conveying operation and the paper feeding operation in the paper feeding device.

  According to a fourth aspect of the present invention, in the first to third aspects of the invention, the paper feed path is longer than one sheet.

  According to this configuration, the paper feed conveyance path is longer than one sheet. As a result, even if the paper feed conveyance path is longer than one sheet, no paper remains in the paper feed conveyance path when stopped due to the occurrence of a non-paper jam. Accordingly, it is possible to reliably simplify the work in the jam processing when the user does not feed any paper.

  According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising: the paper feeding device according to any one of the first to fourth aspects; a main body conveyance path that conveys a sheet fed from the paper feeding conveyance path; An image forming unit that forms an image on the paper, and a discharge unit that discharges the image-formed paper to the outside. The paper feeding device stops the conveyance when a non-paper jam occurs. The main body conveyance path stops after the conveyance of all the sheets carried in from the sheet feeding device, and the image forming unit displays images on all the sheets carried in from the sheet feeding device. The sheet is stopped after the formation is completed, and the discharge unit is stopped after all the sheets carried from the sheet feeding device are discharged.

  According to this configuration, when the sheet feeding device stops conveying due to the occurrence of a non-sheet feeding jam, the main body conveyance path stops after conveying all the sheets carried from the sheet feeding device, and the image forming unit The process is stopped after the image formation is completed on all the sheets carried in from the sheet feeding device, and the discharge unit is stopped after all the sheets carried in from the sheet feeding device are ejected. As a result, even if the sheet feeding rotator and the sheet feeding conveyance path of the sheet feeding device are stopped due to the non-sheet feeding jam, the image is not printed until the printing is completed on all the sheets carried from the sheet feeding apparatus to the main body conveying path. Formation (printing) continues. Therefore, when a paper-free jam occurs, the user does not have to remove the paper in the main body conveyance path or the image forming unit, and confirms the paper loading state in the paper feeding device (causes the paper-free jam to occur). Jam processing for a paper-free jam can be completed simply by performing (confirmation of the received paper).

  According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the information processing apparatus further includes a notification unit that notifies the status of the sheet feeding device and the image forming apparatus. When the paper feed stop and the transport stop are performed, it is notified that a non-paper jam has occurred in the paper feeder.

  According to this configuration, the notifying unit notifies that a non-paper jam has occurred in the paper feeding device when the paper feeding device has stopped feeding and stopped due to the occurrence of a paper non-feed jam. As a result, the user can recognize that a non-paper jam has occurred in the paper feeder.

  According to the present invention, it is possible to reduce the stop of paper feeding and conveyance due to a non-paper jam by appropriately performing retry within a range that does not result in complicated control. Further, since the no-feed state is not solved and the no-feed jam is eliminated, it is not necessary to remove the sheet from the feed conveyance path even when the conveyance in the sheet feeding device is stopped. It is possible to simplify the jam handling operation.

1 is a schematic front sectional view showing a schematic structure of an image forming apparatus. 2 is a block diagram illustrating an example of a hardware configuration of an image forming apparatus. FIG. 6 is a timing chart for explaining the operation of the paper feeding device according to the first embodiment when a paper-free jam occurs. 10 is a flowchart illustrating an example of a flow of detection of a non-paper jam on the first sheet of a print job. 12 is a flowchart illustrating an example of a flow of detecting a paper-free jam on the first sheet of a print job. 12 is a timing chart for explaining the operation of the paper feeding device according to the second embodiment when a paper-free jam occurs.

  First, the first embodiment will be described with reference to FIGS. Thereafter, the second embodiment will be described with reference to FIG. In the following description of each embodiment, a printer 100 (corresponding to an image forming apparatus) including the paper feeding device 1 connected as an optional device will be described as an example. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
First, an image forming apparatus (printer 100) provided with a sheet feeding device 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a schematic front sectional view showing a schematic structure of an image forming apparatus.

  As indicated by a broken line in FIG. 1, an operation panel 2 (corresponding to a notification unit) is provided on the upper portion of the printer 100. Further, in the main body of the printer 100 of the present embodiment, a paper feeding unit 3, a main body conveyance path 4a, an image forming unit 5a, a fixing unit 5b, and a discharge unit 4b are provided. A paper feeding device 1 as an optional device is attached to the side of the main body of the printer 100.

  The operation panel 2 includes a liquid crystal display unit 21 that displays a message such as an error occurrence or a setting state. In addition, the operation panel 2 includes an indicator 22 (for example, LED) that displays a message by turning on and off. The indicator 22 is turned on or off to show messages such as “printing”, “printable state”, “out of paper, jamming, etc.”. In addition, the operation panel 2 is provided with a setting key 23 for receiving setting of the size of the paper P accommodated in the paper supply destination, the paper supply unit 3 and the paper supply device 1.

  The paper feed unit 3 is a device for paper feed and is installed in the printer 100 as a standard. Then, the paper feeding unit 3 supplies the paper P toward the image forming unit 5a. The paper feed unit 3 includes a cassette 31 (indicated by reference numeral 31a on the upper side and 31b on the lower side in FIG. 1) in which paper P such as paper P of each size is stored. Further, the paper feed unit 3 includes a pickup roller 32 (indicated by 32a on the upper side and 32b on the lower side in FIG. 1) for feeding the paper P from each cassette 31 to the main body conveyance path 4a one by one. . When printing is performed, the pickup roller 32 is rotationally driven by a motor (not shown) or the like, and the paper P is supplied to the main body conveyance path 4a.

  Each cassette 31 has a paper placement table 33 on which a plurality of papers P are placed (in FIG. 1, the upper one is denoted by 33a and the lower one is denoted by 33b). Each paper placement table 33 has various types (plain paper, recycled paper, thick paper, thin paper, coat, etc.) of various sizes (for example, A size, B size, letter size, etc. such as A4 paper, A3 paper, B4 paper, etc.) A paper P such as a paper or an OHP sheet can be placed. For example, about 500 sheets of paper P can be stacked on the paper mounting table 33. In order to regulate the position of the paper P, the trailing edge regulating guide 34 (in FIG. 1, 34a is attached to the upper one and 34b is given to the lower one) or the paper P is slid so as to sandwich the paper P in the paper conveyance direction. A pair of width regulating guides 35 (indicated by reference numerals 35a on the upper side and 35b on the lower side in FIG. 1) are provided.

  The main body conveyance path 4a conveys the paper P toward the image forming unit 5a. In the main body conveyance path 4a, a guide (not shown) for guiding the paper P, a plurality of conveyance roller pairs 41, 42, and the like are provided. The main body conveyance path 4a is also provided with a registration roller pair 43 that feeds the paper P to the image forming unit 5a in synchronization with the toner image formation in the image forming unit 5a.

  The image forming unit 5a forms a toner image and transfers the toner image onto the paper P that has been transported through the main body transport path 4a. Specifically, the image forming unit 5a includes a photosensitive drum 51 that is rotatably supported in the direction of the arrow shown in FIG. 1, a charging device 52 that is disposed around the photosensitive drum 51, an exposure device 53, and a developing device. 54, a transfer roller 55, and a cleaning device 56.

  An image forming process in the image forming unit 5a will be described. First, the photosensitive drum 51 is provided substantially at the center of the image forming unit 5a and is driven to rotate in a predetermined direction. The charging device 52 uniformly charges the surface of the photosensitive drum 51 to a predetermined potential. The exposure device 53 outputs laser light based on the image data, and scans and exposes the photosensitive drum 51. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 51. The developing device 54 supplies toner toward the electrostatic latent image. As a result, the electrostatic latent image is developed as a toner image. A nip is formed between the transfer roller 55 and the photosensitive drum 51. When the paper P passes through the nip, a predetermined voltage is applied to the transfer roller 55, and the toner image on the photosensitive drum 51 is transferred to the paper P. Is transferred to. The cleaning device 56 cleans the surface of the photosensitive drum 51 after the transfer.

  The fixing unit 5b fixes the toner image transferred onto the paper P. The fixing unit 5b according to the present embodiment mainly includes a heating roller 57 incorporating a heating element, and a pressure roller 58 that presses against the heating roller 57 to form a nip. The heating roller 57 and the pressure roller 58 rotate. The heating roller 57 and the pressure roller 58 cause the toner to be melted and heated by passing the paper P while feeding the paper P on which the toner image is transferred. As a result, the toner image is fixed on the paper P.

  The discharge unit 4 b discharges the image-formed paper P that has passed through the fixing unit 5 b to the discharge tray 44. Further, a discharge roller pair 45 is provided in the paper transport path in the discharge unit 4b. The discharge roller pair 45 rotates at the time of image formation, and conveys the paper P that has passed through the fixing unit 5 b toward the discharge tray 44.

  Further, a discharge sensor 46 for detecting discharge of the paper P to the discharge tray 44 is provided in the vicinity of the discharge roller pair 45 of the discharge unit 4b. The discharge sensor 46 is, for example, a transmissive optical sensor provided with an actuator that rotates when in contact with the paper P. The output of the discharge sensor 46 changes depending on whether the presence of the paper P is detected or not. The discharge sensor 46 is not limited to the transmission type optical sensor, but may be a reflection type optical sensor that detects the arrival and passage of the paper P by the reflected light from the paper P, and is not limited to the optical sensor. (For example, an ultrasonic sensor) may be used as long as it can detect the arrival and passage of the paper P.

  Next, the paper feeding device 1 attached to the side surface of the printer 100 will be described. The paper feeder 1 supplies paper P. Then, the paper P is carried into the main body conveyance path 4a and conveyed toward the image forming unit 5a. In FIG. 1, only one paper feeding device 1 is illustrated, but a plurality of paper feeding devices 1 may be stacked and connected to the printer 100.

  The paper feeding device 1 has a paper placement table 11 on which a plurality of papers P are placed. There are various types (plain paper, recycled paper, thick paper, thin paper, coated paper) of various sizes (for example, A size, B size, letter size, etc. such as A4 paper, A3 paper, B4 paper, etc.) , OHP sheets, etc.) can be placed. For example, about 500 to 1000 sheets of paper P can be stacked on the paper mounting table 11. In order to regulate the position of the paper P, a rear end regulation guide 12 and a pair of width regulation guides 13 that slide so as to sandwich the paper P and regulate in a direction perpendicular to the paper conveyance direction are provided.

  A paper feed roller 6 (corresponding to a paper feed rotator) is provided above the paper placement table 11. The sheet loading table 11 is biased upward on the downstream side in the sheet conveyance direction by a spring or a motor. As a result, the uppermost sheet P among the sheets P stacked on the sheet feeding roller 6 and the sheet placing table 11 is always in contact. The paper feed roller 6 is driven to rotate. The paper feed roller 6 feeds the paper P toward the paper feed conveyance path 7 in the paper feed device 1.

  The paper feed conveyance path 7 in the paper feed apparatus 1 conveys the paper P sent out from the paper feed roller 6 toward the main body conveyance path 4a in the printer 100 while changing the direction by 180 degrees. The downstream end of the paper feed conveyance path 7 in the paper conveyance direction is connected (joined) to the main body conveyance path 4a. For paper conveyance, the paper feed conveyance path 7 includes conveyance roller pairs 71, 72, and 73 in order from the upstream side in the paper conveyance direction. Each conveyance roller pair 71, 72, 73 is rotationally driven to convey the paper P. Since the paper conveyance direction is changed by 180 degrees, the length of the paper feed conveyance path 7 is longer than the maximum paper size that can be accommodated by the paper feed device 1.

  Further, in order to detect whether or not the paper P is fed from the paper placing table 11, the paper feed conveyance path 7 includes a paper feed sensor 8 (corresponding to a paper detector). As shown in FIG. 1, the paper feed sensor 8 is provided in the vicinity of the paper feed roller 6 and downstream of the paper feed roller 6 in the paper transport direction. In other words, the paper feed sensor 8 is provided between the transport roller pair 71 and the paper feed roller 6.

  The paper feed sensor 8 is a transmissive optical sensor having an actuator that rotates when it contacts the paper P, for example, as with the above-described discharge sensor 46. When the paper P is not present, the actuator blocks the optical path between the light emitting part and the light receiving part, and when the actuator rotates in contact with the paper P, the light from the light emitting part reaches the light receiving part, and the output of the light receiving part (sensor) is Change. The paper feed sensor 8 is not limited to the transmission type optical sensor, but may be a reflection type optical sensor that detects the arrival and passage of the paper P by the reflected light from the paper P, and is not limited to the optical sensor. A kind of sensor (for example, an ultrasonic sensor) may be used as long as it can detect arrival and passage of the fed paper P.

  Further, the paper supply device 1 can open and close the top cover 14 for paper replenishment and jam processing. For example, the top cover 14 can be opened and closed in the direction of the solid line arrow in FIG. Further, the top cover 14 may be removable.

(Hardware configuration of image forming apparatus)
Next, an example of a hardware configuration of the image forming apparatus (printer 100) including the sheet feeding device 1 according to the first embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the image forming apparatus.

  As shown in FIG. 2, the printer 100 according to the present embodiment includes a main control unit 9 (control board) inside. The main control unit 9 controls the overall operation of the apparatus and controls each unit of the printer 100. The main control unit 9 includes, for example, a CPU 91, a ROM 92, a RAM 93, and an image processing unit 94 as a central processing unit. The main control unit 9 includes a main control unit that performs overall control, communication control, and image processing, and an engine control unit that controls ON / OFF of the motor 96 that rotates the image forming and various rotating bodies. May be provided in a form divided into a plurality of types.

  The main control unit 9 of the printer 100 is equipped with a storage device such as a ROM 92 or a RAM 93. For example, an EEPROM or the like can be adopted as the ROM 92. The ROM 92 stores a program executed by the CPU 91 for control. The ROM 92 stores data necessary for controlling the printer 100 and various control data such as various parameters unique to the apparatus. The main control unit 9 (the CPU 91) reads the program and data in the ROM 92 into the RAM 93 and performs control using the read program and data.

  The printer 100 also includes a communication unit 95 as an interface with the outside. The communication unit 95 communicates with, for example, an external computer 200 (for example, a personal computer or a server) via a network or a cable. The communication unit 95 includes, for example, a connector for network connection, a connector for directly communicating with the computer 200 via a cable, a controller for communication control, a chip, and the like. The communication unit 95 receives printing data including image data and setting data for printing from the computer 200 or the like. Then, the main control unit 9 causes the image forming unit 5a to perform printing based on the image data.

  The main control unit 9 is communicably connected to the paper feed unit 3 that actually performs paper conveyance and printing, the main body conveyance path 4a, the image forming unit 5a, and the fixing unit 5b. The main control unit 9 controls operations of the paper feeding unit 3, the main body conveyance path 4a, the image forming unit 5a, the fixing unit 5b, and the discharge unit 4b. Further, when printing is performed, various types of rotating bodies (such as a pair of conveyance rollers 41 and 42 and a photosensitive drum 51 for paper conveyance) used for paper supply from the paper supply unit 3, paper conveyance, and image formation are rotated. The motor 96 and the clutch 97 used are controlled (a plurality of motors 96 and clutches 97 can be provided, but they are collectively shown).

  Further, various sensor outputs such as the discharge sensor 46 are input to the main control unit 9. Based on the output of the discharge sensor 46, the main control unit 9 recognizes whether the printed paper P has been discharged to the discharge tray 44.

  The main control unit 9 is also communicably connected to the operation panel 2 via a bus or the like. For example, the main control unit 9 controls display on the liquid crystal display unit 21 (see FIG. 1) of the operation panel 2. In addition, pressing of the setting key 23 in the operation panel 2 is recognized. Then, a signal indicating the setting contents made on the operation panel 2 is sent to the main control unit 9. Based on the signal, the main control unit 9 recognizes the setting on the operation panel 2 that specifies the size of the paper stored in the paper feeding device 1, for example.

  The main control unit 9 includes an image processing unit 94 that performs various types of image processing on the image data. The image processing unit 94 may be provided outside the main control unit 9. The image processing unit 94 includes, for example, an ASIC as a dedicated circuit for image processing, an image processing memory, and the like. Then, the image processing unit 94 performs various image processing such as density change and enlargement / reduction on the image data, for example. Since image processing that can be performed by the image processing unit 94 is diverse, detailed description of executable image processing is omitted assuming that known image processing can be performed. Then, the image processing unit 94 converts the image data into a form that can be used by the exposure apparatus 53 and passes the image data to the exposure apparatus 53. The exposure device 53 scans and exposes the photosensitive drum 51 based on the delivered data.

  The main control unit 9 is communicably connected to the sheet feeding device 1 through a bus, a communication line, or the like. In the paper feeding device 1, a paper feeding control unit 10 that actually controls the operation of the paper feeding device 1 is provided. In addition, the sheet feeding device 1 is provided with, for example, an I / F unit 15 for communicating with the main control unit 9. The paper feed control unit 10 communicates with the main control unit 9 via the I / F unit 15. When receiving a paper feed instruction accompanying printing from the main control unit 9, the paper feed control unit 10 actually controls the paper feed device 1 to feed the paper P into the printer 100.

  For example, the paper feed control unit 10 includes elements that perform arithmetic processing such as a CPU and an ASIC. The paper feeding device 1 is provided with a memory 16 for storing a program and data for controlling the paper feeding device 1. The paper feed control unit 10 controls the operation of the paper feed device 1 using programs and data stored in the memory 16.

  The paper feed controller 10 controls the rotation of the transport motor 17 that rotates the transport roller pairs 71 to 73 and the paper feed roller 6 in the paper feeder 1. When feeding paper, the paper feed control unit 10 rotates the carry motor 17 so that the paper P is carried at a predetermined speed. In response to the driving force of the transport motor 17, the transport roller pairs 71 to 73 rotate.

  In addition, a paper feeding clutch 18 for turning on / off the rotation of the paper feeding roller 6 is provided so that the paper P is transported with a constant paper gap when printing continuously over a plurality of pages. The paper feed clutch 18 is, for example, an electromagnetic clutch and is controlled by the paper feed control unit 10. The sheet feeding roller 18 can be stopped while the pair of conveying rollers 71, 72, 73 is rotated by the sheet feeding clutch 18. The paper feed control unit 10 controls the paper feed clutch 18 to control the stop and rotation of the paper feed roller 6. A plurality of motors such as a motor for the transport roller pairs 71 to 73 and a motor for the paper feed roller 6 are provided in the paper feed device 1, and the paper feed control unit 10 feeds the transport roller pairs 71, 72, and 73. The rotation of the paper roller 6 may be controlled independently.

  In addition, the output of the paper feed sensor 8 is input to the paper feed controller 10. Based on the output of the paper feed sensor 8, the paper feed control unit 10 confirms whether the paper P is being fed (whether no paper jam has occurred). For example, the paper feed control unit 10 checks whether or not the paper feed sensor 8 has detected the paper P within a predetermined allowable time t0 after the pickup roller 32 is rotated.

  In addition, the paper feeding device 1 is provided with a size sensor 19 for detecting the size of the paper stored in the paper feeding device 1. The size sensor 19 outputs a signal indicating the position of the rear end restriction guide 12 and a signal indicating the position of the width restriction guide 13. For example, the size sensor 19 includes a variable resistor whose resistance value varies depending on the position of the rear end regulation guide 12 and a variable resistor whose resistance value varies depending on the position of the width regulation guide 13, and has different voltages depending on the position of each guide. Output the value. Alternatively, the size sensor 19 may include a plurality of optical sensors according to the position of the paper size. Based on the output of the size sensor 19, the paper feed control unit 10 recognizes the positions of the rear end regulation guide 12 and the width regulation guide 13 and recognizes the paper size.

(Retry and operation stop)
Next, a paper feed retry in the paper feeding device 1 according to the first embodiment will be described with reference to FIG. FIG. 3 is a timing chart for explaining the operation of the paper feeding device 1 according to the first embodiment when a non-paper jam occurs.

  For example, the paper feed roller 6 may slip due to wear of the paper feed roller 6, dust (for example, paper dust) attached to the paper feed roller 6, a coefficient of friction on the paper surface, adsorption between papers, or the like. There is. In addition, the paper P may be caught by a member of the paper feeding device 1. Thus, due to various factors, the paper P may not be sent out even when the paper feed roller 6 is rotated (no paper feed state).

  On the other hand, once the paper feeding roller 6 is stopped and the paper feeding is retried (when rotation is started again) when the paper feeding state is not reached, the paper P can be sent out from the paper placing table 11 in some cases. Is present (elimination of no-feed condition).

  Then, the printer 100 and the paper feeding device 1 according to the present embodiment stop the rotation of the paper feeding roller 6 for retry when a non-paper feeding state occurs. Then, a predetermined number of times (a specified number of times) are retried (if the paper P is sent out, the remaining number of retries is canceled). Then, even if the retry is repeated, the no-feed state continues. If the arrival of the paper P cannot be detected by the paper feed sensor 8 within the allowable time t0 even after the last retry, the paper feed control unit 10 Is determined to have occurred.

  If it is determined that a non-paper jam has occurred, the paper feed control unit 10 keeps the paper feed roller 6 stopped until the non-paper jam is resolved. In addition, the paper feed control unit 10 stops the rotation of the plurality of transport roller pairs 71, 72, 73, and stops the paper transport in the paper feed transport path 7 until the paper-free jam is resolved (feed by retry). Rotate until it is determined that no paper jam has occurred). For example, the transport motor 17 is stopped. After stopping the paper feeding operation and the paper transporting operation, the user performs jam processing in the paper feeding device 1. Note that a sensor (cover opening / closing sensor) that detects opening / closing of the upper surface cover is provided, and if the upper surface cover is opened / closed, the paper feed control unit 10 may recognize that the no-paper jam has been resolved.

  Further, the paper feed conveyance path 7 has a length of one sheet or more. Then, in the sheet conveyance from the second sheet to the last page in continuous printing, when the sheet feeding roller 6 is feeding, the sheet P that has been fed (the sheet fed before the occurrence of no sheet jam) P, the paper P) that has passed through the paper feed sensor 8 exists in the paper feed conveyance path 7. For this reason, if the paper feeding device 1 is stopped immediately after detecting the occurrence of a non-paper jam, the paper feeding device 1 is stopped in a state where the paper P exists in the paper feeding conveyance path 7. Then, in the jam handling operation for the non-feed jam, it is necessary to check the loading state of the paper P and take out the paper P from the paper feed path 7.

  Therefore, in the paper feeding device 1 and the printer 100 according to the present embodiment, when a non-paper jam occurs, the paper feed control unit 10 feeds the paper P (paper P fed immediately before the paper feeding jam). ) Is discharged from the paper feeding device 1, the operation of the paper feeding device 1 (paper feeding, conveyance, etc.) is stopped. Further, when the operation of the printer 100 is stopped in accordance with the stop of the operation of the paper feeding device 1, the printer 100 stops with the paper P carried in from the paper feeding device 1 remaining in the printer 100. Therefore, the main control unit 9 of the printer 100 according to the present embodiment completes conveyance, printing, and discharging for all the sheets P carried from the sheet feeding device 1 when the sheet feeding device 1 is stopped due to occurrence of a non-sheet feeding jam. Then, the conveyance, printing, and discharging operations are stopped.

  Therefore, the retry and operation stop of the sheet feeding device 1 according to the present embodiment will be described with reference to FIG. FIG. 3 shows an example in which the specified number of retries is two. Further, referring to FIG. 3, even if the retry is performed a specified number of times (twice), the no-feed state continues, the feed sensor 8 does not detect the arrival of the sheet, and the feed control unit 10 detects that a no-feed jam has occurred. The case where it was made (judged) will be described. FIG. 3 illustrates an example in which a non-paper jam occurs in the second and subsequent sheets P when performing continuous printing.

  First, FIG. 3 includes two timing charts. The upper timing chart shows ON / OFF of the driving of the paper feed roller 6. The lower timing chart shows ON / OFF of driving of each of the transport roller pairs 71, 72, 73. In each timing chart, High means rotation and Low means stop. Above the two timing charts, the detection and operation flows when a paper-free jam occurs are shown in chronological order.

  A time point T1 in FIG. 3 is a time point at which feeding of the paper P to be fed is started. The paper feed control unit 10 rotates the paper feed roller 6 with the paper feed clutch 18 in a connected state.

  Next, a time point T2 in FIG. 3 is a time point when the permissible time t0 has elapsed from the time point T1 without detecting the arrival of the paper P, although the paper feeding is started. The paper feed control unit 10 measures various times during paper feed while checking the output of the paper feed sensor 8 (for example, the paper feed control unit 10 includes a timer and a counter). The paper feed controller 10 determines that the paper feed sensor 8 is in the no paper feed state when the paper feed sensor 8 has not detected the arrival of paper at time T2. Then, the paper feed control unit 10 opens the paper feed clutch 18 and stops the paper feed roller 6.

  At this time, the paper feed control unit 10 determines whether the paper P that has been fed immediately before the paper P to be fed is detected immediately after the first no-feed state is detected (may be from the start of the first paper feed). A required discharge time t1 (time from T2 to T5 in FIG. 3) until the paper is conveyed from the paper feed conveyance path 7 is obtained. The sheet interval is determined, and the sheet conveyance speed is also determined in advance. Therefore, the required discharge time t1 is obtained according to the paper size, and for example, data indicating the required discharge time t1 is stored in the memory 16. Alternatively, the required discharge time t1 may be measured in advance according to the paper size by experiments or the like, and data indicating the required discharge time t1 determined based on the measurement result may be stored in the memory 16. Then, the paper feed control unit 10 may obtain the required discharge time t1 based on the data indicating the required discharge time t1 stored in the memory 16.

  Further, the paper conveyance speed is determined in advance. The paper size is also recognized by the size sensor 19. The distance from the paper feed start position to the end of the paper feed conveyance path 7 is also determined. In addition, the length to be transported from the start of paper feeding until the paper P is discharged from the paper feed transport path 7 is the distance from the paper feed start position to the end of the paper feed transport path 7 in the paper size (in the paper transport direction). (Size) plus the length. Therefore, if the length to be transported from the start of paper feeding until the paper P is discharged from the paper feed transport path 7 is divided by the paper transport speed, the paper P is discharged from the paper feed transport path 7 from the start of paper feeding. (Ideal) time is required. Then, from the (ideal) time until the paper P is discharged from the paper feeding / conveying path 7 from the start of paper feeding, the paper P to be fed from the start of feeding of the paper P fed immediately before is 1 If the time until the time when the non-feed state is detected for the second time is reduced, the required discharge time t1 can be obtained. Thus, the paper feed control unit 10 may obtain the required discharge time t1 by calculation.

  In this embodiment, the paper feed control unit 10 divides the determined required discharge time t1 by the specified number of times to determine a retry interval (retry interval). The paper feed control unit 10 of the present embodiment causes the paper feed roller 6 to perform a retry based on the determined retry interval.

  A time T3 in FIG. 3 is a start time of the first paper feed retry. Time T3 is a time when the retry interval has elapsed from time T2 (time when the paper feed roller 6 is stopped by the first paper feed). Alternatively, the retry interval may be determined as a time from the start time (time T1) of the previous paper feed. In this case, time point T3 is a time point at which the retry interval has elapsed from time point T1 (the first paper feed start time point). The paper feed controller 10 measures the time from the time point T1 or the time point T2. When the retry interval elapses, the paper feed control unit 10 rotates the paper feed roller 6 with the paper feed clutch 18 in the connected state.

  Next, a time point T4 in FIG. 3 is a time point when the allowable time t0 has elapsed without being able to detect the arrival of the paper P from the time point T3. The paper feed controller 10 measures the time from the start of paper feed while checking the output of the paper feed sensor 8. The paper feed controller 10 determines that the paper feed sensor 8 remains in the no paper feed state when the paper feed sensor 8 has not detected the arrival of paper at time T4. Then, the paper feed control unit 10 opens the paper feed clutch 18 and stops the paper feed roller 6.

  A time point T5 in FIG. 3 is a time point when the paper P fed immediately before is discharged from the paper feeding device 1. In other words, it is the time when the required discharge time t1 has elapsed from the time T2. At this time, the rear end of the sheet P that has been fed immediately before is removed from the sheet feed path 7.

  A time T6 in FIG. 3 is a start time of the second paper feed retry. In other words, time T6 is the time when the retry interval has elapsed from time T4 (when the allowable time t0 has elapsed from the previous paper feed (first retry) and the paper feed roller 6 has stopped). Alternatively, when the retry interval is determined as an elapsed time from the previous paper feed, time T6 is a time when the retry interval has elapsed from time T4 (retry start time).

  In addition, time T7 in FIG. 3 is a time when the allowable time t0 has passed without being able to detect the arrival of the paper P, although the second retry (the last in the specified number of times) has been performed. The paper feed controller 10 measures the time from the start of paper feed while checking the output of the paper feed sensor 8. The paper feed controller 10 determines that no paper jam has occurred when the paper feed sensor 8 has not detected the arrival of paper at the time T7 when the allowable time t0 has elapsed. Then, the paper feed control unit 10 opens the paper feed clutch 18 and stops the paper feed roller 6. Then, the paper feed control unit 10 maintains the paper feed roller 6 in a stopped state until the no-paper jam is resolved.

  Further, at time T5, the paper P fed immediately before from the paper feeding device 1 has already been removed. However, since there is a possibility that paper will be fed by retrying, the pair of transport rollers 71, 72, and 73 remain rotated in the paper feed transport path 10 after time T5. When the paper feed control unit 10 determines that no paper feed jam has occurred at time T7, the paper feed control unit 10 stops the transport roller pairs 71, 72, and 73. In this way, when it is detected that no paper feed jam has occurred at time T7, the paper feed control unit 10 stops the operation of the paper feed device 1 for the paper feed jam processing.

  The paper P carried into the printer 100 is used for printing. When no paper jam occurs, printing of all the paper P carried from the paper feeder 1 to the printer 100 is completed and discharged to the discharge tray 44 (time T8 in FIG. 3). The main control unit 9 stops the operations of the main body conveyance path 4a, the image forming unit 5a, the discharge unit 4b, and the like for the processing of the paper-free jam.

(Non-feed jam detection on first sheet P)
Next, based on FIG. 4, an example of the flow of detecting a non-paper jam in the first paper P fed from the paper feeding device 1 according to the first embodiment will be described. FIG. 4 is a flowchart showing an example of the flow of detecting a non-paper jam on the first sheet P of a print job.

  For example, printer 100 driver software for using the printer 100 is installed in the computer 200. Then, the computer 200 transmits data indicating the content to be printed (for example, image data) to the printer 100. With this printer 100 driver software, it is possible to set the paper size used for printing, the selection of the paper feeding unit 3 and paper feeding device 1 for feeding paper, the number of copies, and the like. If the paper size stored in the paper feeding device 1 matches the paper size set by the printer 100 driver software, or the paper feeding from the paper feeding device 1 is designated, the main control unit 9 selects the sheet feeding device 1 as a sheet feeding source, and gives a sheet feeding instruction to the sheet feeding control unit 10. When the operation panel 2 is set to set the paper feed source to the paper feed device 1, the main control unit 9 may select the paper feed device 1 as the paper feed source.

  Then, the start of FIG. 4 is a time point at which paper feeding from the paper feeding device 1 is performed based on an instruction from the main control unit 9. At this time, the paper feed control unit 10 receives information from the main control unit 9 such as information indicating that paper feed should be performed and the number of papers to be fed. In this way, the paper feed control unit 10 starts the paper feed control in response to an instruction from the main control unit 9.

  Then, the paper feed control unit 10 rotates the paper feed roller 6 to start feeding the first paper P (step # 1). Next, based on the output of the paper feed sensor 8, the paper feed controller 10 checks whether or not the paper feed sensor 8 has detected the arrival of paper within the allowable time t0 (step # 2). The allowable time t0 is, for example, a time obtained by dividing the transport distance from the paper feed roller 6 to the paper feed sensor 8 by the specified paper transport speed (peripheral speed of the peripheral surface of the paper feed roller 6), or this time Is a time (for example, several hundred milliseconds) with a slight margin.

  If the arrival of the paper P cannot be detected (No in Step # 2), the paper feed control unit 10 temporarily stops the paper feed roller 6 (Step # 3). The paper feed control unit 10 stops the paper feed roller 6 and waits for a predetermined waiting time, and then rotates the paper feed roller 6 again (retry, step # 4). Unlike the retry interval, this waiting time is determined in advance and may be shorter than the retry interval.

  Then, the paper feed controller 10 confirms again whether or not the paper feed sensor 8 has detected the arrival of paper within the allowable time t0 (step # 5). If paper arrival cannot be detected (No in step # 5), the paper feed control unit 10 confirms whether or not the retry has been performed a predetermined number of times (step # 6). The specified number of times can be determined arbitrarily, but is, for example, about 2 to 3 times.

  If the retry has not been performed a prescribed number of times (No in step # 6), the flow returns to step # 3. On the other hand, if the retry has already been performed a predetermined number of times (Yes in step # 6), the paper feed control unit 10 stops the paper feed operation (stops the paper feed roller 6; step # 7). The paper feed control unit 10 determines (detects) that no paper feed jam has occurred, and notifies the main control unit 9 of the occurrence of no paper feed jam (step # 8). In response to this notification, the main control section 9 notifies the liquid crystal display section 21 and the indicator 22 of the operation panel 2 that a paper-free jam has occurred (step # 9). And this control is complete | finished (end).

  When a paper-free jam occurs, the user removes the upper surface cover 14 of the paper feeding device 1 and performs processing of the paper-free jam such as checking the loading state of the paper P on the paper loading table 11. . Then, after the processing of the non-paper jam is completed, the process starts again from step # 1.

  When the main body of the printer 100 receives the notification, the main control unit 9 stops the image forming operation if the image forming operation for printing is started. If the main control unit 9 is operating, the main conveyance unit 4 stops the sheet conveyance to the main body conveyance path 4a, stops the operation related to the image formation in the image forming unit 5a and the fixing unit 5b, and performs the discharge operation in the discharge unit 4b. Stop.

  On the other hand, if arrival of the paper P can be detected by the paper feed sensor 8 within the allowable time t0 from the start of the rotation of the first paper feed roller 6 or from the start of retry (Yes in step # 2, Yes in step # 5). Then, the sheet P is conveyed by the sheet feeding conveyance path 7.

  The paper feed roller 6 stops after rotating until the trailing edge of the paper P passes through the paper feed roller 6. For example, the paper feed control unit 10 recognizes the paper size by the size sensor 19. The paper transport speed (circumferential speed) of the paper feed roller 6 is determined in advance. Therefore, for example, the paper feed control unit 10 detects the arrival of the paper with the paper feed sensor 8 and then transports a length obtained by subtracting the distance between the paper feed roller 6 and the paper feed sensor 8 from the paper size. The paper feed roller 6 is rotated during the time. Alternatively, when the arrival of the paper P is detected within the allowable time t0, the paper feed control unit 10 may rotate the paper feed roller 6 for a fixed time from the start of paper feeding according to the paper size.

  As a result, the conveyed first sheet P joins the main body conveyance path 4a. Then, printing on the paper P is performed and discharged to the discharge tray 44. In this way, no-paper jam detection and conveyance are performed on the first sheet P of the print job (end).

(Non-feed jam detection on second and subsequent sheets of paper P)
Next, based on FIG. 5, an example of non-feed jam detection on the second and subsequent sheets P fed from the sheet feeder 1 according to the first embodiment will be described. FIG. 5 is a flowchart illustrating an example of the flow of detecting a non-paper jam on the first sheet P of a print job.

  Therefore, the flow of control relating to detection of no-feed jam in the second and subsequent sheets P will be described with reference to FIG.

  First, the start of FIG. 5 is, for example, the time when the first sheet P passes through the paper feed sensor 8. At this time, the paper feed control unit 10 stops the paper feed roller 6.

  The paper feed controller 10 then feeds the paper P that has been fed immediately before (if the paper P to be fed next is the nth paper, the (n-1) th paper P) and the paper P to be fed from now on. It is checked whether or not the sheet interval is a predetermined sheet interval (whether or not a sufficient sheet interval is secured) (step # 11). For example, the paper feed control unit 10 may recognize the securement between the papers based on the elapsed time since the paper feed sensor 8 detects the passage of the paper P. Further, the paper feed control unit 10 may confirm whether or not the paper gap is secured based on the elapsed time from the start of feeding of the paper P fed immediately before. In step # 11, the feed roller 6 is rotated at regular intervals, and the main controller 9 controls the time to stop the pair of registration rollers 43 of the main body so as to ensure the necessary sheet gap. It may be.

  The paper feed control unit 10 continues the confirmation until a paper gap is secured (No in step # 11 → loop in step # 11). If the necessary paper space can be secured (Yes in step # 11), the paper feed control unit 10 rotates the paper feed roller 6 to start feeding the second and subsequent sheets of paper P (step # 12). Next, based on the output of the paper feed sensor 8, the paper feed controller 10 checks whether or not the paper feed sensor 8 has detected the arrival of paper within the allowable time t0 (step # 13). The allowable time t0 is the same as in step # 2.

  If arrival of the paper P cannot be detected (No in Step # 13), the paper feed control unit 10 temporarily stops the paper feed roller 6 (Step # 14). The paper feed controller 10 stops the paper feed roller 6 (from detection of no paper feed state), waits for a retry interval, and then rotates the paper feed roller 6 again (retry) (step # 15).

  Then, the paper feed controller 10 confirms again whether or not the paper feed sensor 8 has detected the arrival of paper within the allowable time t0 (step # 16). If paper arrival cannot be detected (No in step # 16), the paper feed control unit 10 checks whether or not the executed retry is the last retry of the specified number of times (step # 17).

  If the executed retry is not the last retry operation (No in step # 17), the flow returns to step # 14. On the other hand, if it is the last retry operation (Yes in Step # 17), the paper feed control unit 10 stops the paper feed roller 6 and the pair of transport rollers 71, 72, 73, and the paper feed operation in the paper feed device 1 is performed. And the conveying operation is stopped (step # 18). Further, the paper feed control unit 10 determines that no paper feed jam has occurred, and notifies the main control unit 9 that no paper feed jam has occurred (step # 19). In other words, the paper feed control unit 10 simultaneously detects the occurrence of no-feed jam, and feeds and transports the paper P that has just been fed from the paper feed transport path 7 while removing the paper P. Stop.

  Upon receiving this notification, the main control unit 9 prints all the sheets P carried into the printer 100 from the sheet feeding device 1, and stops the image forming operation after all the sheets P are discharged to the discharge tray 44. (Step # 20). In other words, the main control unit 9 stops the conveyance to the main body conveyance path 4a after completing the conveyance of all the sheets carried in from the sheet feeding device 1, and finishes the image formation on all the sheets conveyed from the sheet feeding device 1. After that, the image forming unit 5a and the fixing unit 5b are stopped, and the discharge unit 4b is stopped after the discharge of all the sheets carried in from the paper feeding device 1 is finished. Further, the main control unit 9 displays on the operation panel 2 that no paper-feed jam has occurred (step # 21). And this control is complete | finished (end).

  When a paper-free jam occurs, the user removes the upper surface cover 14 of the paper feeding device 1 and performs processing of the paper-free jam such as checking the loading state of the paper P on the paper loading table 11. . Then, after completion of the paper-free jam processing, the first page of the unprinted pages is set as the first page, and the process is repeated from step # 1 in FIG.

  On the other hand, if arrival of the paper P can be detected by the paper feed sensor 8 from the start of rotation of the first paper feed roller 6 or within an allowable time t0 from the start of retry (Yes in step # 13, Yes in step # 16). The paper P is transported by the paper feed transport path 7 (step # 22). At this time, the paper feed controller 10 temporarily stops the paper feed roller 6 as the trailing edge of the paper P is fed from the paper feed roller 6. The transported paper P joins the main body transport path 4a, is printed, and is discharged to the discharge tray 44.

  Next, the paper feed control unit 10 confirms whether or not the feeding of all the sheets in the print job has been completed (step # 23). If the feeding of all sheets P has been completed (Yes in step # 23), this flow ends (END). If the feeding of all sheets P has not been completed (No in step # 23), the flow returns to step # 11.

  In this way, the sheet feeding device 1 according to the present embodiment is connected to the conveyance path (main body conveyance path 4a) outside the sheet feeding device 1, and conveys the paper P toward the conveyance path outside the sheet feeding device 1. A paper detection path (paper feed sensor 8) for detecting the arrival and passage of the fed paper P is provided in the paper feed transport path 7 and the transport path of the paper feed transport path 7, and toward the paper feed transport path 7. When the paper detection unit detects that the paper P does not reach the paper P within the predetermined allowable time t0 after the rotation is started, the paper detector stops and rotates in the no paper supply state. The retry retry is performed again after waiting for the retry interval, and the retry interval is determined by the paper P that has been fed immediately before the first non-feed state of the paper P to be fed is detected. Predetermined discharge time t1 until discharging from the paper transport path 7 is determined in advance. When the paper rotation body (paper feed roller 6) does not detect the arrival of the paper P even after retrying the specified number of times, When the paper jam occurs, the paper feeding path 7 stops without retrying, and the paper feed path 7 does not detect the arrival of the paper P even after a specified number of retries. Is discharged from the paper feed conveyance path 7, the paper feed is stopped due to the occurrence of no paper jam.

  As a result, when the paper feeding device 1 stops operating due to the occurrence of a non-paper jam, the paper P that has been fed before the non-paper jam occurs does not remain in the paper feed path 7. Accordingly, it is possible to eliminate the operation of removing the paper P from the paper feed conveyance path 7 by the jam handling of the non-paper jam. In addition, retrying is performed a predetermined number of times or less before the paper P fed immediately before is discharged from the paper feed conveyance path 7. Thereby, it is possible to prevent unnecessary retrying from being performed while urging the feeding of the paper P so that the paper feeding device 1 does not stop due to the non-paper jam. Further, a retry is performed based on an interval obtained by dividing the required discharge time t1 until the paper P, which has been fed immediately before the occurrence of no paper jam, is discharged from the paper feed path 7 by a predetermined number of times. Since the execution timing is taken, the control is equivalent to simply extending the conventional retry interval, and the control is not complicated. Alternatively, it may occur that the paper detection body (paper feed sensor 8) does not reach the paper detection body (paper feed sensor 8) even if paper is fed. Since it is only necessary to remove only the sheet remaining in the paper feed path 7 due to the occurrence of the jam, the jam processing work is facilitated.

  In addition, after the rotation of the sheet feeding rotator (sheet feeding roller 6) is stopped, it waits for the retry interval obtained by dividing the required discharge time t1 by the specified number of times, and then performs the retry. As a result, a retry is performed at a timing close to the discharge of the paper P from the paper feeding device 1, and if no paper feeding state continues thereafter, the paper feeding device 1 performs a transport operation or paper feeding operation as a non-paper feeding jam. Stopped. Therefore, when a paper-free jam occurs and the paper P that has been fed before the paper-free jam is discharged from the paper feeding device 1, the paper feeding and transport in the paper feeding device 1 are immediately stopped.

  Further, the paper feed conveyance path 7 is longer than one sheet. As a result, even if the paper feed conveyance path 7 is longer than one sheet of paper, no paper P remains in the paper feed conveyance path 7 when stopped due to the occurrence of a paper non-feed jam. Accordingly, it is possible to reliably simplify the work in the jam processing when the user does not feed any paper.

  The image forming apparatus (in this embodiment, the printer 100) is arranged in the above-described paper feeding device 1, the main body conveyance path 4a that conveys the paper P sent from the paper feeding conveyance path 7, and the paper conveyance path. An image forming unit 5a that forms an image on the paper P, and a discharge unit 4b that discharges the image-formed paper P to the outside. The transport path 4a stops after transporting all the paper P carried from the paper feeding device 1, and the image forming unit 5a forms an image on all the paper P carried from the paper feeding device 1. It stops after finishing, and the discharge part 4b stops after discharging all the paper P carried in from the paper feeding device 1. As a result, even if the sheet feeding rotator (the sheet feeding roller 6) and the sheet feeding conveyance path 7 of the sheet feeding device 1 are stopped due to the non-sheet feeding jam, all the sheets carried from the sheet feeding apparatus 1 to the main body conveyance path 4a. The image formation (printing) is continued until printing for P is completed. Therefore, when a non-paper jam occurs, the user does not have to remove the paper P in the main body conveyance path 4a or the image forming unit 5a, and confirms the loading state of the paper P in the paper feeding device 1 (unpaid) It is possible to finish the jam-free jam processing by simply checking the paper P that caused the paper jam.

  Further, the image forming apparatus (the printer 100 in the present embodiment) includes a paper feeding device 1 and a notifying unit (operation panel 2) for notifying the state of the image forming apparatus. When the paper feeding stop and the transport stop are performed due to the occurrence, the fact that no paper feeding jam has occurred in the paper feeding device 1 is notified. As a result, the user can recognize that a non-paper jam has occurred in the paper feeder 1.

(Second Embodiment)
Next, a paper feed retry in the paper feeding device 1 according to the second embodiment will be described with reference to FIG. FIG. 6 is a timing chart for explaining the operation of the sheet feeding device 1 according to the second embodiment when a non-sheet feeding jam occurs.

  The second embodiment is different from the first embodiment only in how to determine the retry interval, and the other points may be the same as the first embodiment (configuration, control flow, etc.). Accordingly, the points common to the first embodiment are based on the contents described as the first embodiment, and the description and illustration are omitted unless specifically described.

  First, FIG. 6 includes two timing charts as in FIG. The two timing charts are the same as those in FIG. As in FIG. 3, in FIG. 6, the flow of detection and operation when a paper-free jam has occurred is shown in chronological order above the two timing charts.

  Therefore, the retry and operation stop of the sheet feeding device 1 according to the second embodiment will be described with reference to FIG. FIG. 6 also shows an example in which the specified number of retries is two. Also, in this description, a case will be described in which the no-feed state continues even if the retry is performed a specified number of times (twice), and the feed control unit 10 detects (determines) that no feed jam has occurred. FIG. 6 also illustrates an example in which a paper-free jam occurs in the second and subsequent sheets P when performing continuous printing.

  A time point T10 in FIG. 6 is a time point when the feeding of the paper P to be fed is started. The paper feed control unit 10 rotates the paper feed roller 6 with the paper feed clutch 18 in a connected state. Next, a time point T11 in FIG. 6 is a time point when the permissible time t0 has passed without detecting the arrival of the paper P, although the paper feeding is started. At this time T10, the paper feed controller 10 determines that there is no paper feed. Then, the paper feed control unit 10 stops the paper feed roller 6. At this time, the paper feed control unit 10 determines a required discharge time t1 (time T11 to T16 in FIG. 6), as in the first embodiment. The method for determining the required discharge time t1 may be the same as in the first embodiment.

  In the present embodiment, unlike the first embodiment, the paper feed control unit 10 illustrates the determined required discharge time t1 as a number greater than the specified number of times (“specified number + α” in FIG. 6. For example, Divide by α = 1.) to obtain the retry interval. For example, α can be an integer of 1 or more. However, if α is too large, the retry interval becomes shorter than the allowable time t0, and cannot be said to be an appropriate retry interval. Therefore, the value of α may be determined so that the retry interval is longer than the time obtained by adding the margin to the allowable time t0.

  A time T12 in FIG. 6 is a start time of the first paper feed retry. Time T12 is the time when the retry interval has elapsed since time T11 (the time when the paper feed roller 6 was stopped in the first paper feed). Alternatively, the retry interval may be determined as the time from the starting time (time T10) of the previous paper feed. In this case, time point T12 is a time point at which the retry interval has elapsed from time point T10 (the first paper feed start time point). The paper feed control unit 10 measures the time from time T10 or time T11. When the retry interval elapses, the sheet feeding clutch 18 is brought into a connected state, and the sheet feeding roller 6 is rotated. In addition, time T13 in FIG. 6 is the time when the allowable time t0 has passed without detecting the arrival of the paper P, although the first retry has been performed. Then, the paper feed control unit 10 stops the paper feed roller 6 at time T13.

  Furthermore, time T14 in FIG. 6 is the start time of the second paper feed retry. In other words, time T14 is the time when the retry interval has elapsed from time T13 (when the paper feed roller 6 has stopped after the allowable time t0 has elapsed since the previous paper feed (first retry)). Alternatively, when the retry interval is determined as an elapsed time from the previous paper feed, time T14 is a time when the retry interval has elapsed from time T12 (retry start time). Further, since the retry is executed based on the interval obtained by dividing the required discharge time t1 by (the specified number of times + α), the time when the allowable time t0 has elapsed from the start of the second retry (time point T15) is near the end of the required discharge time t1. (Time T16). Then, the paper feed controller 10 stops the paper feed roller 6 at time T15 as the non-paper feed state continues. Then, the paper feed control unit 10 maintains the paper feed roller 6 in a stopped state until the no-paper jam is resolved.

  In the example of FIG. 6, after the time T15 when the allowable time t0 has passed in the no-feed state since the start of the last retry, the time reaches the time T16 when the required discharge time t1 elapses. Therefore, there is no problem even if each of the transport roller pairs 71, 72, 73 provided in the paper feed transport path 7 in the paper feeder 1 is stopped at the time T16 when the required discharge time t1 has elapsed. In other words, the sheet P does not remain in the sheet feeding conveyance path 7 even when the conveyance roller pairs 71, 72, 73 are stopped at the time T14 when the discharge required time t1 has elapsed.

  In this manner, the sheet feeding rotator (sheet feeding roller 6) of the sheet feeding device 1 according to the present embodiment is obtained by dividing the required discharge time t1 by a number greater than the specified number after stopping the rotation. It was decided to retry after waiting for the specified retry interval. As a result, the paper P that has been fed before the occurrence of the no-feed jam has been fed before the occurrence of the no-feed jam while reliably performing a predetermined number of retries until it is discharged from the feed conveyance path 7. In accordance with the discharge of the paper P from the paper feeding device 1, the transport operation and paper feeding operation in the paper feeding device 1 can be quickly stopped.

  The embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention is applicable to a sheet feeding device or an image forming apparatus including the sheet feeding device.

DESCRIPTION OF SYMBOLS 100 Printer (image forming apparatus) 1 Paper feed apparatus 10 Paper feed control part 6 Paper feed roller (paper feed rotating body)
7 Paper feed path 8 Paper feed sensor (paper detector)
2 Operation panel (notification part) 4a Main body conveyance path 4b Discharge part 5a Image forming part P Paper t0 Allowable time t1 Discharge required time

Claims (6)

A paper feed transport path that is connected to a transport path outside the paper feed device and transports paper toward the transport path outside the paper feed device;
A paper detector that is provided in a transport path of the paper feed transport path and detects the arrival and passage of the fed paper;
The paper is sent out toward the paper feed conveyance path, and stopped when the paper detector detects a paper-free state in which the arrival of the paper cannot be detected within a predetermined allowable time after starting rotation, A paper feed rotating body that performs a retry of rotating again after waiting for a retry interval after stopping rotation in the no-paper supply state,
The retry interval is set in advance to a required discharge time from when the first paper-no-feed state of the paper to be fed is detected until the paper fed immediately before is ejected from the paper feed path. Less than the time obtained by dividing by the specified number of times,
When the paper detection body cannot detect the arrival of paper even after performing the specified number of retries, the paper feed rotating body is in a stopped state without retrying as a non-paper jam has occurred,
If the paper detector cannot detect the arrival of the paper even after retrying the specified number of retries, the paper feed path is not fed after the paper fed immediately before is discharged from the paper feed path. A paper feeding device that stops conveyance when a jam occurs.   The said sheet feeding rotation body performs the said retry after waiting for the said retry interval obtained by dividing | segmenting the said discharge required time by the said predetermined number of times after stopping rotation. Paper feeder.   The paper feeding rotating body waits for the retry interval obtained by dividing the required discharge time by a number larger than the specified number of times after stopping the rotation, and then performs the retry. The sheet feeding device according to 1.   The sheet feeding device according to claim 1, wherein the sheet feeding conveyance path is longer than one sheet. A sheet feeding device according to any one of claims 1 to 4,
A main body transport path for transporting paper fed from the paper feed transport path;
An image forming unit arranged on the paper transport path and forming an image on the paper;
A discharge unit for discharging image-formed paper to the outside,
When the paper feeding device stops the conveyance due to occurrence of a non-paper jam,
The main body conveyance path stops after conveying all the sheets carried from the sheet feeding device,
The image forming unit stops after forming an image on all sheets carried from the sheet feeding device,
The image forming apparatus according to claim 1, wherein the discharging unit stops after discharging all the sheets carried in from the sheet feeding device. Including a notifying unit for notifying the state of the sheet feeding device and the image forming apparatus;
The notifying unit notifies that a non-paper jam has occurred in the paper feeding device when the paper feeding device stops the paper feeding and the conveyance due to the occurrence of a paper non-feed jam. The image forming apparatus according to 5.

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