Patent Publication Number: US-10775730-B2

Title: Sheet feeding apparatus and image forming apparatus

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a sheet feeding apparatus configured to feed sheets and an image forming apparatus. 
     Description of the Related Art 
     In general, an image forming apparatus such as a printer can feed sheets of a plurality of sizes. The image forming apparatus is configured to receive sheets of standard sizes such as A4 and B5 in cassettes and to place a sheet, which is long in a conveying direction (hereinafter referred to as “long sheet”), on a manual feed tray. 
     Hitherto, there has been proposed an image forming apparatus including the following manual feed tray (Japanese Patent Application Laid-Open No. 2007-031093). Specifically, the manual feed tray includes a first retaining portion and a second retaining portion. The first retaining portion is configured to retain a front part of the long sheet. The second retaining portion is configured to retain a rear part of the long sheet. A guide portion configured to determine a posture of an intermediate part of the long sheet is formed integrally with the first retaining portion. The long sheet is received in an upwardly curled posture by the first retaining portion, the second retaining portion, and the guide portion. Therefore, the image forming apparatus can be made compact. However, due to influence of a reaction force generated by the curl of the long sheet and a self-weight of the long sheet, a force of pressing the long sheet into a feed roller pair (hereinafter referred to as “press-in force”) is exerted on a leading end of the long sheet. When the press-in force is large, the leading end of the long sheet undesirably passes beyond a nip of the feed roller pair, which may cause a feeding failure. In view of the disadvantage described above, there has been proposed the following image forming apparatus (Japanese Patent Application Laid-Open No. 2010-013276). Specifically, in the image forming apparatus, a first retaining member configured to retain the front part of the long sheet has a recessed portion. The long sheet is curved downward in the recessed portion so as to reduce the press-in force. 
     However, in particular, when the long sheet has a large stiffness, the image forming apparatus described in Japanese Patent Application Laid-Open No. 2010-013276 cannot sufficiently reduce the press-in force because the long sheet is substantially not curved in the recessed portion. Thus, a feeding failure may be caused. 
     SUMMARY OF THE INVENTION 
     According to one embodiment of the present invention, there is provided a sheet feeding apparatus, comprising: 
     a stacking portion on which sheets are stacked; 
     a feeding portion configured to feed the sheets stacked on the stacking portion; 
     a separation portion configured to separate one by one the sheets fed by the feeding portion; 
     a sheet detector configured to detect the sheets stacked on the stacking portion; 
     a moving portion configured to move one of the feeding portion and the stacking portion relative to the other of the feeding portion and the stacking portion so as to bring the feeding portion into a contact state in which the feeding portion is in contact with an uppermost sheet of the sheets stacked on the stacking portion and a separation state in which the feeding portion is separated from the sheets stacked on the stacking portion; and 
     a controller configured to control the moving portion so as to bring the feeding portion into the contact state at a time of start of a sheet feed job for feeding the sheets, 
     wherein the controller is configured to execute control in a first mode in which the controller controls the moving portion so as to bring the feeding portion into the separation state regardless of whether the sheet detector detects a sheet after end of feeding of a final sheet in the sheet feed job, and execute control in a second mode in which the controller controls the moving portion so as to maintain the feeding portion in the contact state when the sheet detector detects a sheet after the end of feeding of the final sheet in the sheet feed job. 
     According to another embodiment of the present invention, there is provided a sheet feeding apparatus, comprising: 
     a stacking portion on which sheets are stacked; 
     a feeding portion configured to feed the sheets stacked on the stacking portion; 
     a separation portion configured to separate one by one the sheets fed by the feeding portion; 
     a sheet detector configured to detect the sheets stacked on the stacking portion; 
     a moving portion configured to move one of the feeding portion and the stacking portion relative to the other of the feeding portion and the stacking portion so as to bring the feeding portion into a contact state in which the feeding portion is in contact with an uppermost sheet of the sheets stacked on the stacking portion and a separation state in which the feeding portion is separated from the sheets stacked on the stacking portion; and 
     a controller configured to control the moving portion so as to bring the feeding portion into the contact state at a time of start of a sheet feed job for feeding the sheets, 
     wherein the controller is configured to control the moving portion so as to maintain the feeding portion in the contact state when the sheet detector detects a sheet after end of feeding of a final sheet in the sheet feed job. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an overall schematic view for illustrating a printer according to a first embodiment. 
         FIG. 2  is a perspective view for illustrating a manual feeding device. 
         FIG. 3  is a side view for illustrating the manual feeding device. 
         FIG. 4  is a control block diagram according to the first embodiment. 
         FIG. 5  is a side view for illustrating a configuration for placing a long sheet. 
         FIG. 6  is a flowchart for illustrating job end control executed in a first mode. 
         FIG. 7  is a flowchart for illustrating the job end control executed in a second mode. 
         FIG. 8  is a control block diagram according to a second embodiment. 
         FIG. 9  is a flowchart for illustrating job end control according to the second embodiment. 
         FIG. 10  is a side view for illustrating a manual feeding device according to another embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     First Embodiment 
     Now, a first embodiment will be described with reference to the accompanying drawings. In the following description, positional relationships including a vertical positional relationship, a horizontal positional relationship, and a positional relationship between a near side and a far side will be described based on a state in which an image forming apparatus is viewed from a front side thereof (from a point of view of  FIG. 1 ). 
     [Image Forming Apparatus] 
     A printer  201  according to the first embodiment is an electrophotographic full-color laser beam printer. As illustrated in  FIG. 1 , the printer  201  includes a printer main body  201 A and a reading apparatus  202 . The printer main body  201 A is a main body. The reading apparatus  202  is provided above the printer main body  201 A and is configured to read image data of an original. 
     The printer main body  201 A includes an image forming portion  201 B, which is configured to form an image on a sheet P, and a fixing portion  220 , which is configured to fix the image onto the sheet P. A delivery space into which the sheet P is delivered is formed between the reading apparatus  202  and the printer main body  201 A. In the delivery space, a delivery tray  230 , on which the delivered sheet P is stacked, is provided. Further, a sheet feeding portion  201 E, which is configured to feed the sheet P to the image forming portion  201 B, is provided in the printer main body  201 A. The sheet feeding portion  201 E includes cassette feeding devices  100 A,  100 B,  100 C, and  100 D, and a manual feeding device  100 M. The cassette feeding devices  100 A,  100 B,  100 C, and  100 D are arranged in a lower part of the printer main body  201 A to contain sheets Pin cassettes  103 , respectively. The manual feeding device  100 M is arranged in a right side portion of the printer main body  201 A. Each of the cassette feeding devices  100 A,  100 B,  100 C, and  100 D, and the manual feeding device  100 M includes a pickup roller  2 , a feed roller  3 , and a retard roller  4 . The pickup roller  2  is configured to feed the sheet P. The feed roller  3  and the retard roller  4  are configured to convey the sheet P while separating the sheets P one by one. 
     The image forming portion  201 B is a so-called four-drum full-color type image forming portion including a laser scanner  210 , four process cartridges  211 , and an intermediate transfer unit  201 C. The respective process cartridges  211  form toner images of yellow (Y), magenta (M), cyan (C), and black (B). Each of the process cartridges  211  includes a photosensitive drum  212 , a charger  213 , a developing device  214 , and a cleaner (not shown). Above the image forming portion  201 B, toner cartridges  215 , which contain toners of the respective colors, are mounted in the printer main body  201 A so as to be freely removable from the printer main body  201 A. 
     The intermediate transfer unit  201 C includes an intermediate transfer belt  216 , which is looped over a drive roller  216   a , a tension roller  216   b , and the like. The intermediate transfer belt  216  is arranged above the four process cartridges  211 . The intermediate transfer belt  216  is arranged so as to be held in contact with the photosensitive drums  212  of the respective process cartridges  211 , and is rotated in a counterclockwise direction (direction indicated by an arrow Q) by the drive roller  216   a , which is driven by a drive portion (not shown). The intermediate transfer unit  201 C includes a primary transfer roller  219 , which is held in abutment against an inner peripheral surface of the intermediate transfer belt  216  at positions opposed to the respective photosensitive drums  212 . Primary transfer portions TP 1  are formed as nip portions between the intermediate transfer belt  216  and the photosensitive drums  212 . Further, the image forming portion  201 B includes a secondary transfer roller  217 , which is held in abutment against an outer peripheral surface of the intermediate transfer belt  216  at a position opposed to the drive roller  216   a . A secondary transfer portion TP 2 , at which the toner images borne on the intermediate transfer belt  216  are transferred onto the sheet P, is formed as a nip portion between the secondary transfer roller  217  and the intermediate transfer belt  216 . 
     In each of the process cartridges  211  having the configuration described above, an electrostatic latent image is formed on a surface of the photosensitive drum  212  by the laser scanner  210 . Thereafter, a toner image of each of the colors, which is charged to have negative polarity, is formed by supplying a toner from the developing device  214 . Through application of transfer bias voltages having positive polarity respectively to the primary transfer rollers  219 , the toner images are sequentially multi-layer transferred onto the intermediate transfer belt  216  at the primary transfer portions TP 1 , thereby forming a full-color toner image on the intermediate transfer belt  216 . 
     In parallel to the above-mentioned image formation process, the sheet P fed from the sheet feeding portion  201 E is conveyed toward a registration roller pair  15 . Skew feed of the sheet P is corrected by the registration roller pair  15 . The registration roller pair  15  conveys the sheet P to the secondary transfer portion TP 2  at timing in accordance with timing to transfer the full-color toner image formed on the intermediate transfer belt  216 . The toner image borne on the intermediate transfer belt  216  is secondarily transferred onto the sheet P at the secondary transfer portion TP 2  through application of a transfer bias voltage having positive polarity to the secondary transfer roller  217 . 
     The sheet P onto which the toner image has been transferred is heated and pressurized at the fixing portion  220  so that the color image is fixed onto the sheet P. The sheet P onto which the image has been fixed is delivered by a delivery roller pair  225  to the delivery tray  230  to be stacked thereon. When images are formed on both sides of the sheet P, the sheet P first passes through the fixing portion  220 . Then, the sheet P is switched back by a reverse roller pair  222 , which is provided in a reverse conveying portion  201 D and can be rotated in a forward direction and a reverse direction. Then, the sheet P is conveyed again to the secondary transfer portion TP 2  through a re-conveyance path R, and the image is formed on a back surface of the sheet P. 
     [Manual Feeding Device] 
     With reference to  FIG. 2  and  FIG. 3 , the manual feeding device  100 M serving as a sheet feeding apparatus will be described. The manual feeding device  100 M includes, as illustrated in  FIG. 2  and  FIG. 3 , a manual feed tray  7 , the pickup roller  2 , the feed roller  3 , and the retard roller  4 . 
     The manual feed tray  7  is supported onto the printer main body  201 A so as to be openable and closeable. An opening and closing angle of the manual feed tray  7  is regulated by tray arms  21 . A pair of side regulating plates  22  and  23 , which is movable in a width direction orthogonal to a sheet feed direction, is provided for the manual feed tray  7 . The side regulating plates  22  and  23  interlock with each other so as to move in directions opposite to each other. The side regulating plates  22  and  23  are moved by a user to regulate positions of ends of the sheet placed on the manual feed tray  7  in the width direction. 
     A detection flag  11   a  (see  FIG. 2 ) is supported on a downstream end portion of the manual feed tray  7  in the sheet feed direction so as to be pivotable. The detection flag  11   a  is retained at a protruding position at which the detection flag  11   a  protrudes upwardly from an upper surface of the manual feed tray  7 . The detection flag  11   a  is pivoted by being pressed by the sheet to block an optical path of a sheet sensor  11  (see  FIG. 4 ) which is configured to detect presence or absence of the sheet as a sheet detector formed of, for example, a photosensor. As a result, the sheet sensor  11  is turned on to detect the sheets stacked on the manual feed tray  7 . When no sheet is left on the manual feed tray  7 , the detection flag  11   a  returns to the protruding position to turn off the sheet sensor  11 . 
     The feed roller  3  is rotatably supported on a rotary shaft  3   a  provided to the printer main body  201 A. A feed arm  5  is supported on the rotary shaft  3   a  so as to be pivotable. The pickup roller  2  serving as a feeding portion is supported on a distal end of the feed arm  5  so as to be rotatable about a rotary shaft  2   a.    
     A drive force is input from a feed motor M 1  (see  FIG. 4 ) to the rotary shaft  3   a  of the feed roller  3 . The drive force of the feed motor M 1  input to the rotary shaft  3   a  is transmitted to the pickup roller  2  through intermediation of a gear train (not shown) supported on the feed arm  5 . The retard roller  4  is supported on a rotary shaft  4   a  through intermediation of a torque limiter (not shown) so as to be rotatable. The retard roller  4  is held in contact with the feed roller  3  with a predetermined contact pressure. A drive force is also input to the rotary shaft  4   a  of the retard roller  4  from the feed motor M 1 . The drive force in a direction opposite to the sheet feed direction, specifically, a direction of returning the sheet to the manual feed tray  7  is input to the retard roller  4 . Further, the torque limiter (not shown) is provided between the retard roller  4  and the rotary shaft  4   a.    
     The feed arm  5  is urged in a direction in which the pickup roller  2  is brought closer to the manual feed tray  7 , specifically, a direction in which the pickup roller  2  is lowered, by, for example, a torsion coil spring (not shown) fitted into the rotary shaft  3   a  of the feed roller  3  by insertion. When the sheet is fed by the pickup roller  2 , the feed motor M 1  is rotated in a first rotating direction. When the feed motor M 1  is rotated in a second rotating direction opposite to the first rotating direction, the feed arm  5  is raised. When the feed motor M 1  is rotated in the first rotating direction, a coil portion of the torsion coil spring is loosened. Thus, the rotation of the rotary shaft  3   a  is not transmitted to the feed arm  5 . Meanwhile, when the feed motor M 1  is rotated in the second rotating direction, the coil portion of the torsion coil spring is tightened. As a result, the rotation of the rotary shaft  3   a  is transmitted to the feed arm  5  through intermediation of the torsion coil spring. Specifically, the torsion coil spring functions as a spring clutch. 
     By the drive of the feed motor M 1  as described above, the feed arm  5  serving as a moving portion is raised and lowered so that a state of the pickup roller  2  is switched between a contact state in which the pickup roller  2  is held in contact with an uppermost sheet of the sheets stacked on the manual feed tray  7  and a separation state in which the pickup roller  2  is separated from the sheets stacked on the manual feed tray  7 . The feed arm  5  may be configured so as to be raiseable by a cam and other components in place of the torsion coil spring. The feed arm  5  may be driven by a motor different from the feed motor M 1  or by a solenoid. 
     At the start of a print job as a sheet feed job using the manual feeding device  100 M as a feed source, the pickup roller  2  is lowered so as to be turned from the separation state into the contact state and is brought into contact with the sheet placed on the manual feed tray  7 . The sheet placed on the manual feed tray  7  is fed by the pickup roller  2  toward a separation nip  34  serving as a separation portion formed by the feed roller  3  and the retard roller  4 . 
     When only one sheet is fed to the separation nip  34  by the pickup roller  2 , the torque limiter provided between the rotary shaft  4   a  and the retard roller  4  spins, and hence the retard roller  4  is dragged by the feed roller  3 . Further, when two or more sheets are fed by the pickup roller  2 , the retard roller  4  is rotated in a direction of returning back the sheet to the manual feed tray  7 . As a result, the second and subsequent sheets are returned back to the manual feed tray  7 . A drive force is not required to be input to the retard roller  4 . Further, in place of the retard roller  4 , a separation pad may be provided. The sheets separated one by one by the separation nip  34  are conveyed to the registration roller pair  15  (see  FIG. 1 ) by a draw roller pair  8  driven by a draw motor M 2 . 
     [Control Block] 
       FIG. 4  is a control block diagram according to the first embodiment. A controller  9  includes a CPU (not shown), a ROM (not shown), a RAM (not shown), and other devices. A program stored in the ROM can be executed by the CPU. A control panel  10  is connected to the controller  9 . The control panel  10  serving as an operating portion can perform various setting for the printer  201  and display a screen based on an output signal from the controller  9 . The sheet sensor  11  and a trailing end tray sensor  24  described later are connected to an input side of the controller  9 . The feed motor M 1  and the draw motor M 2  are connected to an output side of the controller  9 . 
     The controller  9  may be provided in the manual feeding device  100 M or may be provided at a location different from the manual feeding device  100 M of the printer  210 . When the controller  9  is provided in the manual feeding device  100 M, the manual feeding device  100 M corresponds to the sheet feeding apparatus. When the controller  9  is provided in the printer  201 , the printer  201  corresponds to the sheet feeding apparatus. 
     [Placement of Long Sheet] 
     Next, with reference to  FIG. 5 , placement of a long sheet LP in the manual feeding device  100 M will be described. Although the “long sheet LP” herein corresponds to a sheet, for example, having a length equal to or larger than 457 mm (18 inches) in a sheet conveying direction, the long sheet LP is not limited thereto. 
     The manual feeding device  100 M includes a trailing end tray  14  and an intermediate guide  13 . The trailing end tray  14  is mountable to and removable from the printer main body  201 A. The intermediate guide  13  is mountable to and removable from a distal end of the manual feed tray  7 . The manual feed tray  7  serving as a first tray, the intermediate guide  13 , and the trailing end tray  14  serving as a second tray form a tray unit  12  serving as a stacking portion. The trailing end tray  14  is provided above the manual feed tray  7  so as to overlap the manual feed tray  7  as viewed in a vertical direction. A mounted state in which the trailing end tray  14  is mounted to the printer main body  201 A and a non-mounted state in which the trailing end tray  14  is not mounted to the printer main body  201 A are detected by a trailing end tray sensor  24  (see  FIG. 4 ) serving as a tray detector. The intermediate guide  13  is formed so as to extend from a distal end of the manual feed tray  7  to an upstream side in the sheet feed direction and to be then bent upward. The manual feed tray  7  and the intermediate guide  13  may be formed integrally. In this case, for the placement of the long sheet LP, the user mounts a manual feed tray for the long sheet LP to the printer main body  201 A. 
     After the placement of the long sheet LP in the manual feeding device  100 M, the long sheet LP is guided so that a leading end is placed on the manual feed tray  7  and an intermediate portion is curved upward by the intermediate guide  13 . A trailing end of the long sheet LP guided by the intermediate guide  13  is supported on the trailing end tray  14 . As a weight of the long sheet LP, a part of the trailing end side is retained by the trailing end tray  14 , and the remaining part is retained by the manual feed tray  7 . Further, when the trailing end of the long sheet LP is brought into pressure contact with the printer main body  201 A, a reaction force applied by curving the long sheet LP is exerted on the leading end side of the long sheet LP. 
     Under a state in which the leading end of the long sheet LP is held in abutment against the separation nip  34 , a force of pressing the long sheet LP into the separation nip  34  (hereinafter referred to as “press-in force”) is exerted on the leading end of the long sheet LP due to influence of a weight of the long sheet and the reaction force. When the press-in force becomes larger than a frictional resistance of the separation nip  34 , the leading end of the long sheet LP may pass beyond the separation nip  34  to result in a feeding failure. 
     [First Mode] 
     Next, raising and lowering control of the pickup roller  2  performed after end of a print job (hereinafter referred to as “job end control”) will be described. The controller  9  of the first embodiment executes the job end control in any one of a first mode and a second mode. First, the job end control in the first mode will be described. 
       FIG. 6  is a flowchart for illustrating the job end control in the first mode. When the print job ends (Step S 1 ), the controller  9  raises the feed arm  5  so that the pickup roller  2  is brought into the separation state (Step S 2 ). Specifically, the controller  9  controls the feed arm  5  so that the pickup roller  2  is brought into the separation state regardless of whether or not the sheet sensor  11  has detected the sheet. Then, the controller  9  is brought into a standby state (Step S 3 ). 
     By the job end control described above, the pickup roller  2  is reliably separated from the manual feed tray  7  after the end of the print job. Therefore, the sheet placed on the manual feed tray  7  can be easily removed, and the sheet can be easily placed on the manual feed tray  7 . 
     As illustrated in  FIG. 5 , however, when the job end control is executed in the first mode described above after the trailing end tray  14  is mounted to the printer main body  201 A and the long sheet LP is placed on the manual feeding device  100 M, the pickup roller  2  is brought into the separation state. Then, the remaining long sheet LP, which has been pressed against the manual feed tray  7  by the pickup roller  2 , is released. Hence, the press-in force of the long sheet LP is undesirably exerted on the separation nip  34 . When a subsequent print job is started in this state, the long sheet LP, which has been pressed into the separation nip  34 , cannot be conveyed, which may result in occurrence of a conveyance failure such as a jam. Therefore, in the first embodiment, the second mode different from the first mode is provided. 
     [Second Mode] 
       FIG. 7  is a flowchart for illustrating the job end control in the second mode. In the flowchart of  FIG. 7  and the following description, “Y” represents YES and “N” represents NO. When the print job ends (Step S 4 ), the controller  9  determines whether or not the sheet sensor  11  has been turned on (Step S 5 ). When the sheet sensor  11  is in an off-state (N in Step S 5 ), the controller  9  raises the feed arm  5  so that the pickup roller  2  is brought into the separation state as in the first mode (Step S 6 ). Then, the controller  9  is brought into the standby state (Step S 7 ). 
     Meanwhile, when the sheet sensor  11  has been turned on (Y in Step S 5 ), the controller  9  controls the feed arm  5  so that the pickup roller  2  maintains the contact state (Step S 8 ). Then, the controller  9  determines again whether or not the sheet sensor  11  has been turned on (Step S 9 ). When the sheet sensor  11  has been turned on (Y in Step S 9 ), the processing performed by the controller  9  returns to Step S 8 . When the sheet sensor  11  is in the off state (N in Step S 9 ), the controller  9  raises the feed arm  5  so that the pickup roller  2  is brought into the separation state (Step S 10 ). Then, the controller  9  is brought into the standby state (Step S 11 ). 
     Specifically, as long as the sheet remains on the manual feed tray  7 , the pickup roller  2  is held in the contact state to regulate the displacement of the long sheet LP on the manual feed tray  7 . Therefore, the press-in force of the long sheet LP is prevented from being intensely exerted on the separation nip  34 . Thus, the occurrence of the feeding failure can be prevented in a subsequent print job. When the subsequent print job is input without removing the sheet on the manual feed tray  7 , the pickup roller  2  is started to be rotated while being maintained in the contact state. 
     Further, after the user removes the sheet placed on the manual feed tray  7  to turn off the sheet sensor  11  under the state in which the pickup roller  2  is in the contact state to be held in contact with the sheet on the manual feed tray  7 , the pickup roller  2  is brought into the separation state. In particular, the detection flag  11   a  (see  FIG. 2 ) is provided to the downstream end portion of the manual feed tray  7  in the sheet feed direction. Therefore, when the user merely pulls out the long sheet LP from the manual feed tray  7  by a small amount, the sheet sensor  11  is turned off. Ease in placement of the sheet is not significantly lost by the above-mentioned operation. 
     In this embodiment, either of the first mode and the second mode can be selected on the control panel  10 . Thus, after mounting the trailing end tray  14  to the printer main body  201 A, the user operates the control panel  10  to select the second mode. In this manner, the controller  9  executes the control in the second mode. The controller  9  may be configured to execute the control in the first mode when the trailing end tray  14  is in the non-mounted state and execute the control in the second mode when the trailing end tray  14  is in the mounted state in accordance with a result of the detection by the trailing end tray sensor  24 . 
     As described above, the controller  9  of the first embodiment can select the first mode when the long sheet LP is not placed on the manual feed tray  7  and select the second mode when the long sheet LP is placed on the manual feed tray  7 . Through selection of the second mode, the pickup roller  2  is maintained in the contact state when the long sheet LP remains on the manual feed tray  7  after the start of the job end control. As a result, the press-in force of the long sheet LP is prevented from being intensely exerted on the separation nip  34 . Thus, the occurrence of the feeding failure can be prevented in the subsequent print job. 
     Second Embodiment 
     Next, a second embodiment will be described. In the second embodiment, the job end control in the second mode according to the first embodiment is modified. An illustration is therefore omitted for the same configurations as those of the first embodiment, or the same configurations are denoted by the same reference symbols in the drawings for description. 
     Either one of the first mode and the second mode is selected in advance before the start of the print job in the first embodiment. However, in the second embodiment, one of the first mode and the second mode is determined in accordance with a length of the sheet conveyed during the print job. Therefore, in the second embodiment, as illustrated in  FIG. 8 , a sheet length sensor  30  is connected to the input side of the controller  9 . The sheet length sensor  30  serving as a sheet length detector includes a flag member and a photosensor, and is provided in a sheet conveyance path in the printer  201 . The flag member is pressed by, for example, the sheet. The photosensor is configured to output a detection signal in accordance with a position of the flag member. A length of the sheet to be conveyed in the sheet feed direction (hereinafter referred to as “sheet length”) is detected by the sheet length sensor  30 . 
       FIG. 9  is a flowchart for illustrating job end control in the second mode according to the second embodiment. After the print job ends (Step S 12 ), the controller  9  determines whether the sheet length of the sheet conveyed during the print job is 457 mm (18 inches) or more based on a result of the detection by the sheet length sensor  30  (Step S 13 ). Although the sheet having the sheet length of 457 mm (18 inches) or more is defined as the long sheet in the second embodiment, the definition of the long sheet is not limited thereto. 
     When the sheet length is smaller than 457 mm (N in Step S 13 ), the controller  9  raises the feed arm  5  so as to bring the pickup roller  2  into the separation state as in the first mode described above (Step S 14 ). Then, the controller  9  is brought into the standby state (Step S 15 ). When the sheet length is equal to or larger than 457 mm (Yin Step S 13 ), the controller  9  performs processing in Step S 16  and subsequent steps. The processing in Step S 16  to Step S 22  is the same as the processing in Step S 5  to Step S 11  illustrated in  FIG. 7  in the first embodiment, and therefore the description thereof is herein omitted. 
     Specifically, in the second embodiment, the controller  9  executes the job end control in the first mode when it is determined that the sheet length is smaller than 457 mm which is a predetermined length in Step S 13  and executes the job end control in the second mode when it is determined that the sheet length is 457 mm or more in Step S 13 . Therefore, the selection of the first mode or the second mode on the control panel  10  is not required. Therefore, an operation burden on the user can be reduced, thereby improving usability. 
     Another Embodiment 
     Although the pickup roller  2  is raised and lowered by the feed arm  5  to press the sheet against the manual feed tray  7  as illustrated in  FIG. 5  in the first embodiment and the second embodiment described above, the configuration is not limited thereto. Specifically, as illustrated in  FIG. 10 , the pickup roller  2  may be configured so as not to be raiseable and lowerable without providing the feed arm  5  (see  FIG. 5 ), and an intermediate plate  43 , which is pivotable, may be provided to the manual feed tray  7 . The intermediate plate  43  forms a part of the tray unit  12 . 
     The intermediate plate  43  is supported on the manual feed tray  7  so as to be pivotable about a pivot shaft  43   a , and is raised and lowered by being pressed by a lift arm  44  serving as a moving portion pivotable about a pivot shaft  44   a . Then, when the intermediate plate  43  is raised to bring the sheet placed on the intermediate plate  43  into contact with the pickup roller  2 , the pickup roller  2  is brought into the contact state. Further, when the intermediate plate  43  is lowered to separate the sheet placed on the intermediate plate  43  from the pickup roller  2 , the pickup roller  2  is brought into the separation state. Further, without raising and lowering the intermediate plate  43  by the lift arm  44 , a drive force of a drive source may be directly input to the pivot shaft  43   a  of the intermediate plate  43  so as to raise and lower the intermediate plate  43 . 
     For the job end control, the pickup roller  2  is suitably brought into the separation state by replacing the raising of the feed arm  5  (pickup roller  2 ) by the lowering of the intermediate plate  43  in the flowcharts of  FIG. 6 ,  FIG. 7 , and  FIG. 9 . As described above, it is only required that one of the pickup roller  2  configured to feed the sheet and the intermediate plate  43  (or the manual feed tray  7 ) on which the sheets are stacked be moved relative to the other of the intermediate plate  43  (or the manual feed tray  7 ) to bring the pickup roller  2  into the contact state or the separation state. In this manner, the same effects as those of the first embodiment and the second embodiment described above can be obtained. 
     Although the job end control is performed in the first mode or the second mode after the end of the print job in all the embodiments described above, the job end control is not limited thereto. Specifically, the job end control may be performed any time after the end of feeding of the final sheet in the print job as the sheet feed job. For example, the above-mentioned job end control may be performed after the end of feeding of the final sheet in the print job and before delivery of the final sheet to the delivery tray  230 . 
     Further, although the job end control can be executed in both the first mode and the second mode in all the embodiments described above, the job end control may be executed only in the second mode. Further, the sheet sensor  11  may be provided not only in the manual feed tray  7  but also in the intermediate guide  13  or the trailing end tray  14 , specifically, at any location in the tray unit  12 . Further, the sheet sensor  11  may be a non-contact type sensor and may be provided at a location different from the tray unit  12 . Specifically, the arrangement and the configuration of the sheet sensor  11  are not limited as long as the sheet sensor  11  can detect the sheets stacked in the tray unit  12 . 
     Although the electrophotographic printer  201  is described in all the embodiments described above, the present invention is not limited thereto. For example, the present invention is also applicable to an ink jet image forming apparatus including a nozzle configured to discharge an ink liquid to form an image on the sheet. Further, the present invention is also applicable to a high-capacity stacker and other devices, which do not include the image forming portion. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2017-164718, filed Aug. 29, 2017, which is hereby incorporated by reference herein in its entirety.