Patent Publication Number: US-2023159291-A1

Title: Sheet feeding apparatus and image forming apparatus

Description:
FIELD OF THE INVENTION AND RELATED ART 
     The present invention relates to a sheet feeding apparatus and an image forming apparatus which is provided with a sheet feeding apparatus. 
     Conventionally, in the image forming apparatus such as a copier and a printer, a feeding mechanism which separates and feeds paper which is a recording material which is stacked in a feeding portion and a conveying mechanism which conveys paper to an image forming portion are provided. For example, in the feeding mechanism, a configuration that a rubber roller is applied to a feeding roller which feeds paper and the paper is fed one sheet by one sheet is generally used. A feeding roller is made of soft and easily worn rubber in order to feed various types of media, and therefore wear on a surface of the feeding roller due to repeated feeds of paper is significant. Further, various factors, such as paper dust adhesion to the feeding roller and deterioration of rubber, degrade paper feeding performance of the feeding roller. In recent years, a main assembly of an image forming apparatus has a long life, and a feeding roller which is subject to severe wear and deterioration is configured to be easily replaceable, so a longer life of the main assembly of the image forming apparatus is supported on an assumption of replacement. 
     The replaceable feeding roller is replaced with a new one by a user or a service person as a consumable article. And various detection methods are proposed so that the main assembly of the image forming apparatus detects a timing of replacement of the feeding roller. For example, in a method disclosed in Japanese Laid-Open Patent Application (JP-A) 2017-007758, a time from a start of rotation of the feeding roller until paper is conveyed to a sensor which is provided downstream of a conveying passage and a delay in conveying the paper is detected based on the measured time. And the main assembly of the image forming apparatus informs a user, etc. that the feeding roller needs to be replaced when an incidence rate of the delay in conveying the paper which is detected exceeds a threshold value. Further, when the main assembly of the image forming apparatus determines that the feeding roller needs to be replaced, it urges the user or the service person to replace the feeding roller in order to prevent conveying failure. 
     And when the feeding roller is replaced by the user or the service person, the image forming apparatus needs to detect that the feeding roller is replaced with a new one and stop a notification operation which urges the user or the service person to replace the feeding roller. Therefore, the user or the service person performs a reset operation, etc. to set the image forming apparatus in a state that the feeding roller is completed to be replaced via an operation panel of the image forming apparatus, etc. The reset operation which is described above is an operation which is performed by an operator such as a user or a service person. Therefore, it is assumed that after the operator replaces the feeding roller with a new one, the operator may forget to perform a reset operation which sets completion of replacement of the feeding roller or to check an operation. In such a case, since the reset operation is not performed, the image forming apparatus determines that a state in which the feeding roller still needs the replacement of the feeding roller is continued and continues to inform the user or the service person that the feeding roller should be replaced. 
     Further, in an image forming apparatus which includes a plurality of sheet feeding ports, it is assumed that an operator may accidentally perform a reset operation to set completion of replacement of the feeding roller of a sheet feeding port which has not been replaced. As a result, the image forming apparatus is not able to correctly detect an actual state of use of the feeding rollers. Therefore, it is desired that the image forming apparatus is able to detect automatically and correctly without any manual work that the feeding roller has been replaced with a new one without resorting to the reset operation by the user or the service person. 
     SUMMARY OF THE INVENTION 
     In response to such situation, an object of the present invention is to automatically detect that a feeding roller has been replaced with a new one. In order to solve the problems which are described above, the present invention is provided with following configurations. 
     A sheet feeding apparatus comprising, a stacking unit provided with a stacking plate on which a sheet is stacked and capable of performing up-and-down operation, a feeding unit provided with a feed roller configured to feed the sheet, a rotatable supporting member configured to support the feed roller, and a detected member provided on the supporting member, a holding unit provided with a detecting device configured to detect the detected member, provided above the stacking unit, and configured to dismountably hold the feeding unit, a drive unit configured to cause the stacking plate to perform the up-and-down operation, and a control unit configured to control the drive unit, wherein the detected member is positioned in a first position where the detected member is not detected by the detecting device in a case that the feeding unit is new, and is moved from the first position to a second position where the detected member is projected so as to be detected by the detecting device when the new feeding unit is mounted on the holding unit and the feed roller is driven, wherein the control unit controls the drive unit to perform the up-and-down operation of the stacking plate so that the stacking plate is set to a feedable state of the sheet stacked on the stacking plate in a case that the feeding unit is mounted, and determines whether or not the feeding unit is new based on a detection result of the detecting device. 
     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 a schematic sectional view showing a configuration of an image forming apparatus according to a first embodiment and a second embodiment of the present invention. 
         FIG.  2   , part (a) and part (b), is a sectional view showing a configuration of a sheet feeding apparatus according to the first embodiment. 
         FIG.  3    is a control block diagram of the sheet feeding apparatus according to the first embodiment. 
         FIG.  4   , part (a) and part (b), is a schematic perspective view showing a configuration of a feeding roller holding unit and a feeding roller unit according to the first embodiment. 
         FIG.  5   , part (a) and part (b), is a sectional view showing ae state of a detecting flag of the feeding roller unit according to the first embodiment. 
         FIG.  6   , part (a) and part (b), is a view illustrating a positional relationship between the detecting flag of the feeding roller unit and a paper surface sensor according to the first embodiment. 
         FIG.  7    is a flowchart showing a new product detecting process of the feeding roller unit according to the first embodiment. 
         FIG.  8   , part (a) and part (b), is a sectional view showing a configuration of the sheet feeding apparatus according to the second embodiment. 
         FIG.  9    is a control block diagram of the sheet feeding apparatus according to the second embodiment. 
         FIG.  10    is a flowchart showing the new product detecting process of the feeding roller unit according to the second embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following, embodiments of the present invention will be specifically described with reference to Figures. 
     First Embodiment 
     [Image Forming Apparatus] 
       FIG.  1    is a schematic sectional view showing a configuration of an image forming apparatus which is provided with a sheet feeding apparatus according to a first embodiment to which the present invention is applied. Here, an electrophotographic color laser printer (hereinafter referred to as a printer  100 ) as an image forming apparatus will be described as an example. The printer  100  uses an electrophotographic method, however, the present invention is not limited to an electrophotographic printer and it is also possible to apply to an inkjet printer, for example. Incidentally, in the embodiment, a part of the printer  100  is configured of the sheet feeding apparatus  10  which feeds a sheet which is a recording material, however, a sheet feeding apparatus may be a feeding deck which is capable of accommodating a plurality of sheets in large quantities which is mounted on the printer  100  as an optional device. 
     The printer  100  is provided with an image forming portion  100 A which forms a toner image which is transferred onto a sheet and the sheet feeding apparatus  10  which feeds a sheet to the image forming portion  100 A which are each surrounded by a dotted line in  FIG.  1   . The image forming portion  100 A is provided with four photosensitive drums  101 Y,  101 M,  101 C and  101 K, in which toner images of four colors, yellow (Y), magenta (M), cyan (C) and black (K) are formed respectively. Incidentally, in  FIG.  1   , each of configurations of the image forming portions which form toner images of respective colors is same, and Y, M, C and K at ends of reference numerals mean members which perform image forming of the toner colors yellow, magenta, cyan and black, respectively. Further, the image forming portion  100 A is provided with an endless intermediary transfer belt  102  which is contacted with these four photosensitive drums  101 Y,  101 M,  101 C and  101 K and to which each toner image which is formed on each of the photosensitive drums  101 Y,  101 M,  101 C,  10   1 K are transferred. Furthermore, the image forming portion  100 A is provided with primary transfer rollers  106 Y,  106 M,  106 C and  106 K which are disposed to oppose the photosensitive drums  101 Y,  101 M,  101 C and  101 K and urge the intermediary transfer belt  102  to the corresponding photosensitive drums  101 . When transfer voltage is applied to the primary transfer rollers  106 Y,  106 M,  106 C and  106 K from a transfer voltage source (not shown), the toner images on the photosensitive drums  101 Y,  101 M,  101 C and  101 K are transferred to the intermediary transfer belt  102 . Furthermore, the image forming portion  100 A is provided with a secondary transfer roller  105  which transfers the toner image, which is transferred from each of the respective photosensitive drums  101 Y,  101 M,  101 C and  101 K to the intermediary transfer belt  102 , to the sheet S which is fed from the sheet feeding apparatus  10 . 
     When the image forming portion  100 A starts an image forming operation, a light beam according to an image signal is emitted from a laser scanner  103  to the photosensitive drums  101 Y,  101 M,  101 C and  101 K whose surfaces are charged at a constant potential. As a result, electrostatic latent images are formed on the photosensitive drums  101 Y,  101 M,  101 C and  101 K. And when the electrostatic latent images are developed with the toner which is accommodated in developer cartridges  104 Y,  104 M,  104 C and  104 K, toner images which are visible images are formed on the photosensitive drums  101 Y,  101 M,  101 C and  101 K. The toner images which are formed on the photosensitive drums  101 Y,  101 M,  101 C and  101 K are transferred to the intermediary transfer belt  102  by the primary transfer rollers  106 Y,  106 M,  106 C and  106 M. And the toner images on the intermediary transfer belt  102  are conveyed to a secondary transfer portion, which is a nip portion which is formed by abutting the secondary transfer roller  105  with the intermediary transfer belt  102 . 
     On the other hand, in parallel with the image forming operation in the image forming portion  100 A which is described above, a sheet S which is stacked in a sheet accommodating unit  50  is fed one by one, by a feeding roller unit  20  and a separating roller unit  40  in the sheet feeding apparatus  10 . The sheet S which is fed is conveyed to the secondary transfer portion by a registration roller  110  which corrects for skewness. Incidentally, since it is necessary to align the toner image which is transferred onto the intermediary transfer belt  102  with a position of the sheet S to which the toner image is transferred with respect to the conveying direction, the registration roller  110  preforms a conveying speed control and adjusts a conveying timing of the sheet S. And, in the secondary transfer portion, the toner image on the intermediary transfer belt  102  is transferred to the sheet S by applying a transfer voltage to the secondary transfer roller  105 . 
     The sheet S onto which the toner image is transferred is then conveyed to a fixing portion  111 , and the toner image is fixed to the sheet S when the toner image is heated and pressed in a fixing portion  111 . And the sheet S to which the toner image is fixed is discharged to a discharge member  113  at the top of the printer  100  by a discharge roller  112 . 
     Incidentally, an operation portion  114 , which includes an operation panel to input data, an image forming instruction, etc. and a displaying member which displays information, is provided. Further, on a right side of the printer  100  which is shown in  FIG.  1   , a right door  115 , in which open and close operation is performed when maintenance work such as replacing the feeding roller unit  20  is performed, is provided. 
     [Sheet Feeding Apparatus] 
     Next, the sheet feeding apparatus  10  to which the present invention is applied will be described. Parts (a) and (b) of  FIG.  2    are sectional views showing a configuration of the sheet feeding apparatus  10 . Part (a) of  FIG.  2    is a diagram showing a state before the sheets S which are stacked in the sheet accommodating unit  50  are lifted up in a direction of the feeding roller unit  20 . On the other hand, part (b) of  FIG.  2    is a diagram showing a state that the sheets S which are stacked in the sheet accommodating unit  50  are lifted up in the direction of the feeding roller unit  20  and a topmost sheet S is positioned at a feeding start position in which the uppermost sheet S is abutted with a pickup roller  21 . The sheet feeding apparatus  10  is configured of the feeding roller unit  20 , a feeding roller holding unit  30 , the separating roller unit  40 , the sheet accommodating unit  50 , a feeding drive unit  60  (see  FIG.  3   ) and a lift-up drive unit  70  (see  FIG.  3   ). 
     (Feeding Roller Unit) 
     The feeding roller unit  20  (a feeding unit) is a feeding means which feeds the sheet S. The feeding roller unit  20  includes a pickup roller  21  and a feeding roller  22  which are feeding members (feeding rollers) which are made of robber material and a roller holder  23  which is a supporting means which rotatably supports the pickup roller  21  and the feeding roller  22 . Further, a detecting flag  24  (a detected member) for detecting a state of the feeding roller unit  20  by a paper surface sensor  32  which will be described below is provided on a left side of the pickup roller  21  in  FIG.  2   . Furthermore, the feeding drive unit  60  (see  FIG.  3   ), which drives the feeding roller unit  20 , rotatably drives the feeding roller  22  and the pickup roller  21 . Incidentally, an idler gear  27  will be described below. 
     (Feeding Roller Holding Unit) 
     The feeding roller holding unit  30  includes a feeding roller supporting member (not shown) which supports the feeding roller unit  20 , a pick spring  31  and the paper surface sensor  32 . The feeding roller unit  20  is rotatably mounted on the feeding roller holding unit  30  around the feeding roller supporting member (not shown). Since a center of rotation of the feeding roller  22  is provided at a same axial position with the feeding roller supporting member (not shown), the feeding roller unit  20  is rotatable around the center of rotation of the feeding roller  22  as a rotational axis. When the feeding roller unit  20  is mounted on the feeding roller holding unit  30 , the pick spring  31  urges the roller holder  23  in a direction of the sheet S. The paper surface sensor  32  which is a detecting device is a photointerrupter which includes a light emitting portion which emits light and a light receiving portion which receives the light which is emitted from the light emitting portion. The paper surface sensor  32  detects a light shielding state in which the detecting flag  24  of the feeding roller unit  20  shields light from the light emitting portion or a light transmitting state in which the light from the light emitting portion is not shielded, and outputs it to a state determining portion  81  (see  FIG.  3   ) of the control portion  80 , which will be described below. For example, in a case that the feeding roller unit  20  is in a state which is shown in part (a) of  FIG.  2   , the detecting flag  24  is in a state in which light from the light emitting portion of the paper surface sensor  32  is not shielded and the paper surface sensor  32  outputs a light transmitting state (a state that the detecting flag  24  is not detected). On the other hand, in a case that the feeding roller unit  20  is in a state which is shown in part (b) of  FIG.  2   , the detecting flag  24  is in a state in which the light from the light emitting portion of the paper surface sensor  32  is shielded and the paper surface sensor  32  outputs a light shielding state (a state that the detecting flag  24  is detected). 
     (Separating Roller Unit) 
     The separating roller unit  40  includes a separating roller  41  which separates the sheet S one by one, a cover member  42  which holds the separating roller  41  and a separating spring  43 . The separating roller  41  is urged in a direction of the feeding roller  22  by the separating spring  43 . In a case that a plurality of the sheets S are fed to a nip portion in which the feeding roller  22  is abutted with the separating roller  41  by the pickup roller  21  of the feeding roller unit  20 , the separating roller  41  separates the sheet S one by one and conveys the sheet S downstream in a conveying passage. 
     Incidentally, in the sheet feeding apparatus  10  of the embodiment, the feeding roller unit  20  and the separating roller unit  40  are configured to be replaced easily by a user or a service person. In detail, in a case of replacing the feeding roller unit  20  or the separating roller unit  40 , it is possible to remove the separating roller unit  40  and the feeding roller unit  20  which are mounted, by opening the right door  115  ( FIG.  1   ) and pulling out the separating roller unit  40  and the feeding roller unit  20  in a right direction which is indicated by X in the figure. And in a case of mounting the feeding roller unit  20  and the separating roller unit  40 , it is possible to mount the feeding roller unit  20  and the separating roller unit  40  by inserting the feeding roller unit  20  and the separating roller unit  40  in a left direction which is indicated by X in the figure. Further, it is possible to detect an open and closed state of the right door  115 , which is a door, by a right door sensor  116  (see  FIG.  3   ) which is an open and close detecting device. 
     (Sheet Accommodating Unit) 
     The sheet accommodating unit  50  is mountable on and dismountable from the sheet feeding apparatus  10  and includes an accommodating cassette  51  which is possible to accommodate the plurality of sheets S. The accommodating cassette  51  is a stacking unit in which the sheet S is stacked, and includes a stacking plate  52  which lifts the stacked sheet S up and down. The lift-up drive unit  70  (see  FIG.  3   ), which will be described below, transmits drive to a lift-up gear (not shown) which is mounted on the stacking plate  52  and lifts the stacking plate  52  up and down as shown in part (b) of  FIG.  2   . 
     [Control Portion of Sheet Feeding Apparatus] 
       FIG.  3    is a control block diagram showing a constitution of a control portion of the sheet feeding apparatus  10 . A control portion  80 , which is a control unit which controls the sheet feeding apparatus  10 , includes the state determining portion  81 , which determines a state based on a signal which is output from each sensors, and a drive control portion  82  which controls a driving unit based on determination of the state determining portion  81  and a timing for feeding the sheet S. The state determining portion  81  determines a state of the feeding roller unit  20  based on a light transmitting state or a light shielding state in which the paper surface sensor  32 , which described above, outputs according to a state of the detecting flag  24  of the feeding roller unit  20 . Further, the state determining portion  81  determines an open and closed state of the right door  115  based on a detection result of the right door sensor  116  which is described above. The drive control portion  82  controls the feeding drive unit  60 , which drives the feeding roller unit  20  which feeds the sheet S and the lift-up drive unit  70  (a drive unit) which lifts the stacking plate  52  up and down on which the sheets S are stacked. 
     [Sheet Feeding Operation] 
     Next, an operation, in which the sheet feeding apparatus  10  feeds the sheet S which is accommodated in the sheet accommodating unit  50  to a conveying passage toward the secondary transfer portion of the image forming portion  100 A of the printer  100 , will be described. The control portion  80  instructs the drive control portion  82  to drive the lift-up drive unit  70 . The drive control portion  82  drives the lift-up drive unit  70  and lifts up the stacking plate  52  of the sheet accommodating unit  50 . Thus, the sheet S, which is stacked on the stacking plate  52  (on a stacking plate), is lifted up in a direction toward the pickup roller  21  and the pickup roller  21  contacts the uppermost sheet S. At this time, the pickup roller  21  is pressed downward from the pick spring  31  via the roller holder  23  in  FIG.  2   . Further, the roller holder  23  is rotatably held around a rotational axis of the feeding roller  22 . Therefore, against a pressing force of the pick spring  31 , the sheet S which is stacked on the stacking plate  52  is lifted up, and the roller holder  23  which supports the pickup roller  21  is also lifted up by pressing force from the sheet S. And the detecting flag  24  which is mounted on the roller holder  23  is also lifted up in an upward direction in  FIG.  2   , and the detecting flag  24  is lifted up is lifted up to a position in which light which is emitted from the light emitting portion of the paper surface sensor  32  is shielded (part (b) of  FIG.  2   ). As a result, a detected state in which the paper surface sensor  32  outputs to the state determining portion  81  of the control portion  80  is changed from a light transmitting state to a light shielding state. 
     When the state determining portion  81  detects a change in the detected state in which the paper surface sensor  32  outputs, that is, a state change of the detecting flag  24 , the state determining portion  81  notifies a change in the state of detecting flag  24  of the control portion  80 . The control portion  80  determines that the sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  is set in a position in which the pickup roller  21  is possible to feed the sheet S, based on the notification of the state change in the detecting flag  24  from the state determining portion  81 . And the control portion  80  instructs the drive control portion  82  to stop driving the lift-up drive unit  70 , and the drive control portion  82  stops driving the lift-up drive unit  70 . By performing the operation which is described above, a preparation, in which the uppermost sheet S which is stacked on the stacking plate  52  is fed to the image forming portion  100 A of the printer  100 , is completed. After that, the control portion  80  instructs the drive control portion  82  to drive the feeding drive unit  60 , the drive control portion  82  starts driving of the feeding drive unit  60 , and the sheet S which is stacked on the stacking plate  52  is conveyed to the image forming portion  100 A. 
     And when the sheet S is fed to the image forming portion  100 A by the pickup roller  21 , since the pickup roller  21  is pressed by the pick spring  31  via the roller holder  23 , the pickup roller  21  descends in a downward direction in  FIG.  2    by the number of sheets S which are fed. As a result, since the detecting flag  24  descends in a downward direction in  FIG.  2    as well, the paper surface sensor  32  detects a state change from a light shielding state to a light transmitting state. When the state determining portion  81  detects that the detected state which is output from the paper surface sensor  32  is changed from a light shielding state to a light transmitting state, the state determining portion  81  notifies the control portion  80  of the state change of the detecting flag  24 . The control portion  80  instructs the drive control portion  82  to drive the lift-up drive unit  70 , and the drive control portion  82  drives the lift-up drive unit  70 . And when the detected state which is output from the paper surface sensor  32  changes from a light transmitting state to a light shielding state, the control portion  80  stops the lift-up drive unit  70 . By the sheet feeding control which is described above, the uppermost sheet S which is stacked on the stacking plate  52  is abutted with the pickup roller  21  at an appropriate position, and is fed to the image forming portion  100 A. 
     [Configuration of Feeding Roller Unit] 
     Next, a detailed configuration of the feeding roller unit  20  will be described. Part (a) and part (b) of  FIG.  4    are views illustrating the configuration of the feeding roller unit  20 . Part (a) of  FIG.  4    is a schematic perspective view of the feeding roller unit  20  when it is viewed from an upper right direction in  FIG.  2   , part (b) of  FIG.  4    is a schematic perspective view of the feeding roller unit  20  when it is viewed from a lower left in  FIG.  2   . 
     As shown in part (a) and part (b) of  FIG.  4   , the pickup roller  21  and the feeding roller  22  are rotatably supported by the roller holder  23 . On one end portion of the pickup roller  21 , a pickup roller gear  25  is integrally mounted, and the other end portion is rotatably supported by the roller holder  23 . Further, on one end portion of the feeding roller  22  which is on a same side as one end portion of the pickup roller  21 , a feeding roller gear  26  is integrally mounted, and the other end portion is rotatably supported by the roller holder  23 . And the idler gear  27  for transmitting a drive of the feeding roller gear  26  to the pickup roller gear  25  is rotatably supported by the roller holder  23  between the pickup roller gear  25  and the feeding roller gear  26 . Further, guide portions  28   a  and  28   b  are provided with the roller holder  23  as guidance guides for preventing incorrect mounting by regulating a direction of mounting and dismounting of the feeding roller unit  20  when a user or a service person performs mounting and dismounting of the feeding roller unit  20 . Incidentally, the guide portion  28   a  is also referred to as a guide portion F and the guide portion  28   b  is also referred as a guide portion R. In the embodiment, to prevent incorrect mounting of the feeding roller unit  20 , an arrow (a guide direction) which indicates an insertion direction of the feeding roller unit  20  is formed on a surface of the guide portion  28   b  which is shown in part (a) of  FIG.  4   . 
     The control, in which the sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  is set at a position in which the pickup roller  21  is possible to feed the sheet S by the control portion  80 , is as described above. Next, a control until the sheet S is fed by the feeding roller unit  20  will be described. In order to feed the sheet S which is stacked on the stacking plate  52 , the control portion  80  instructs drive of the feeding drive unit  60  to the drive control portion  82 . When the drive of the feeding drive unit  60  is started by the control of the drive control portion  82 , the drive of the feeding drive unit  60  is transmitted to the feeding roller gear  26  via a gear train (not shown) which is provided with the feeding roller holding unit  30 . When the feeding roller gear  26  is driven, the feeding roller  22  is rotationally driven and the idler gear  27  is driven. And when the idler gear  27  is driven, the pickup roller gear  25  is driven, and when the pickup roller gear  25  rotationally drives the pickup roller  21 , a feeding operation of the sheet S is started. 
     [Control of Detecting Flag] 
     Part (a) and part (b) of  FIG.  5    are sectional views illustrating a state of the detecting flag  24  of the feeding roller unit  20 , part (a) of  FIG.  5    shows a state of the detecting flag  24  in a case that the detecting flag  24  is positioned at a retracted position, and part (b) of  FIG.  5    shows a state of the detecting flag  24  in a case that the detecting flag  24  is positioned at a projected position. As described above, when the detecting flag  24  transmits or shields the light from the light emitting portion of the paper surface sensor  32 , the paper surface sensor  32  detects a state of the detecting flag  24 . Based on a state of the detecting flag  24  which is detected by the paper surface sensor  32 , the control portion  80  controls height at which the stacking plate  52  of the sheet accommodating unit  50  is lifted up. 
     The feeding roller unit  20  includes a configuration in which the detecting flag  24  is possible to move from the retracted position which is shown in part (a) of  FIG.  5    to the projected position which is shown in part (b) of  FIG.  5   . Next, a method of maintaining the retracted position and the projected position of the detecting flag  24  of the feeding roller unit  20 , and a method of moving the detecting flag  24  from the retracted position to the projected position, which are characteristic configurations of the present invention, will be described by using part (a) and part (b) of  FIG.  5   . 
     In the detecting flag  24  which is shown in part (a) of  FIG.  5   , a convex portion  24   a  is a convex portion which protrudes in a direction of the pickup roller  21 , and when the detecting flag  24  is in the retracted position, the convex portion  24   a  is held in a state that rubber material of the pickup roller  21  is concaved. Further, as shown in part (a) of  FIG.  5   , an abutting portion  24   b  is an inclined surface which is abutted with a state holding spring  29  when the detecting flag  24  is in the retracted position (a first position). The state holding spring  29  (a pressing portion) is provided to hold a state of the detecting flag  24  and a torsion coil spring is used for the state holding spring  29 . On the other hand, as shown in part (b) of  FIG.  5   , an abutting portion  24   c  is an inclined surface which is abutted with the state holding spring  29  when the detecting flag  24  is in the projecting position (a second position). Further, an abutting portion  24   d  is an abutting portion which is provided on a side of the detecting flag  24 , and an abutting portion  23   a  is an abutting portion which is provided on a side of the roller holder  23 . As will be described below, when the detecting flag  24  moves to a left direction in the figure, the abutting portion  24   a  of the detecting flag  24  abuts against the abutting portion  23   a  of the roller holder  23 , so the detecting flag  24  is prevented from moving further to the left direction in the figure. 
     As shown in part (a) and part (b) of  FIG.  5   , both arm portions of the state holding spring  29  is fixed to the roller holder  23 . When the detecting flag  24  moves from a state in which the detecting flag  24  abuts against the abutting portion  24   b  which is shown in part (a) of  FIG.  5    to a state in which the detecting flag  24  abuts against the abutting portion  24   c  which is shown in part (b) of  FIG.  5   , a coil portion of the state holding spring  29  moves in an up and down direction in the figure along a shape of the detecting flag  24  which abuts against. Incidentally, the detecting flag  24  is possible to move in a right and left direction in  FIG.  5   , however, the detecting flag  24  is restricted from moving in the up and down direction and a depth direction in  FIG.  5    by the roller holder  23 . 
     First, in a case that the detecting flag  24  is positioned at the retracted position which is shown in part (a) of  FIG.  5   , a configuration in which the detecting flag  24  holds a state of the retracted position will be described. As described above, in a case that the detecting flag  24  is positioned at the retracted position, the coil portion of the state holding spring  29  abuts against the abutting portion  24   b  of the detecting flag  24 . As shown in part (a) of  FIG.  5   , the coil portion of the state holding spring  29  presses the abutting portion  24   b  in an upward direction in the figure. However, since the abutting portion  24   b  is the inclined surface, the state of the retracted position of the detecting flag  24  is held by converting a direction of pressing force which is applied from the coil portion of the state holding spring  29  to a direction along the inclined surface (a retracted direction). 
     Next, an operation, when the detecting flag  24  moves from the retracted position to the projected position, will be described. When the detecting flag  24  is positioned in the retracted position in which the coil portion of the state holding spring  29  abuts against the abutting portion  24   b,  the convex portion  24   a  of the detecting flag  24  is held in a state that the rubber material of the pickup roller  21  is concaved. By the control of the control portion  80 , the drive of the feeding drive unit  60  is transmitted to the pickup roller  21  via the feeding roller gear  26 , the idler gear  27  and the pickup roller gear  25 , and the pickup roller  21  starts rotating in an arrow direction (a counterclockwise direction) in part (a) of  FIG.  5   . Then, the convex portion  24   a  of the detecting flag  24  is pushed out in a rotational direction of the pickup roller  21  (in a projecting direction) against a holding force of the state holding spring  29  (a pressing force against the detecting flag  24 ). As a result, an abutting part of the detecting flag  24  against the coil portion of the state holding spring  29  moves from the abutting portion  24   b  to the abutting portion  24   c.  Even in a neutral point in which a direction of the pressing force of the state holding spring  29  against the detecting flag  24  switches, that is, a peak portion of the inclined surface between the abutting portion  24   b  and the abutting portion  24   c  of the detecting flag  24 , the convex portion  24   a  maintains a state that the rubber of the pickup roller  21  is concaved. Therefore, the coil portion of the state holding spring  29 , which abuts against the detecting flag  24 , moves beyond the neutral point to a side of the inclined surface of the abutting portion  24   c,  and the detecting flag  24  is securely pushed toward the projected position (to a side of a left direction in part (b) of  FIG.  5   ). 
     Further, since the abutting portion  24   c  of the detecting flag  24  is an inclined surface, by converting a direction of pressing force which is applied from the coil portion of the state holding spring  29  to a direction along the inclined surface (a projected direction), the detecting flag  24  is moved in a direction toward the projected position. And when the detecting flag  24  moves in a projecting direction (in a left direction in the figure), by abutting the abutting portion  24   d  of the detecting flag  24  and the abutting portion  23   a  of the roller holder  23 , the movement of the detecting flag  24  is completed. Incidentally, in the projected position in which the abutting portion  24   d  of the detecting flag  24  and the abutting portion  23   a  of the roller holder  23  abut, the coil portion of the state holding spring  29  and the abutting portion  24   c  of the detecting flag  24  continue to abut. Thus, since the detecting flag  24  is pressed in the direction toward the projected position by the coil portion of the state holding spring  29 , the detecting flag  24  is held in a state that the detecting flag  24  is positioned in the projected position. Incidentally, in a case of a state of the projected position in which the coil portion of the state holding spring  29  abuts against the abutting portion  24   c  of the detecting flag  24 , the convex portion  24   a  of the detecting flag  24  is spaced away from the rubber material of the pickup roller  21  and does not interfere with the pickup roller  21 . Therefore, the detecting flag  24  is configured that once the detecting flag  24  is shifted to the state of the projected position, the detecting flag  24  will not return to a state of the retracted position in which the coil portion of the state holding spring  29  abuts against the abutting portion  24   b  of the detecting flag  24 . 
     As described above, by being configured that the detecting flag  24  is movable, it is possible to move the detecting flag  24  from the retracted position to the projected position. Further, by interfering the detecting flag with the rubber material of the pickup roller  21  and providing the state holding spring  29 , it is possible to securely move from the retracted position to the projected position by using a small space. 
     [New Product Detection of Feeding Roller Unit  20 ] 
     Next, a new product detection of the feeding roller unit  20  will be described. Part (a) of  FIG.  6    shows a following state. That is, part (a) of  FIG.  6    is a view showing a state that the feeding roller unit  20  in which the detecting flag  24  is held in the state of the retracted position, is inserted into (mounted on) the feeding roller holding unit  30 , and is in a position that the pickup roller  21  is possible to feed the sheet S by the lift-up drive unit  70 . At this time, since the detecting flag  24  is positioned in a position away from the paper surface sensor  32 , the paper surface sensor  32  is in the light transmitting state and does not detect the detecting flag  24 . On the other hand, part (b) of  FIG.  6    show a following state. That is, part (b) of  FIG.  6    is a view showing a state that the feeding roller unit  20  in which the detecting flag  24  is held in the state of the projected position, is inserted into (mounted on) the feeding roller holding unit  30 , and is in a position that the pickup roller  21  is possible to feed the sheet S by the lift-up drive unit  70 . At this time, since the detecting flag  24  is in a state which shields the light which is emitted from the paper surface sensor  32 , the paper sensor  32  detect the detecting flag  24 . 
     First, a positional relationship of the detecting flag  24  when the feeding roller unit  20  is replaced will be described. As described above, a new product of the feeding roller unit  20  is in a state that the detecting flag  24  is positioned in the retracted position. When the feeding roller unit  20  is replaced with a new product, a user or a service person opens the right door  115  and dismounts the separating roller unit  40  and the feeding roller unit  20  which are used. And the user or the service person mounts the new product of the feeding roller unit  20  and the separating roller unit  40 , and closes the right door  115 . A state of the detecting flag  24  at this time is a state which is shown in part (a) of  FIG.  2   . And the lift-up drive unit  70  is driven and the stacking plate  52  of the sheet accommodating unit  50  is lifted up, and the sheet S which is stacked on the stacking plate  52  is raised in a direction of the pickup roller  21  and the pickup roller  21  and the uppermost sheet S are contacted. By driving the lift-up drive unit  70  for a predetermined period of time, the feeding roller unit  20  is set to be a state which is shown as part (a) of  FIG.  6   , in which the sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  is possible to be fed by the pickup roller  21 . After that, when the feeding roller unit  20  is driven, as described above, the detecting flag  24  moves from the retracted position to the projected position, and as shown in part (b) of  FIG.  6   , the paper surface sensor  32  is set to the light shielded state. Incidentally, in the feeding roller unit  20  in which the detecting flag  24  is moved to the projected position, the detecting flag  24  is configured that a state of the projected position is continued to be held. 
     [Control Sequence for Replacing Feeding Roller Unit] 
     Next, a control sequence which performs a detection of a replacing operation of the feeding roller unit  20  and a detection of a new product of the feeding roller unit  20  will be described.  FIG.  7    is a flowchart showing the control sequence for replacing the feeding roller unit  20 . A process which is shown in  FIG.  7    is performed by the control portion  80  when a power source of the printer  100  is turned on and the control portion  80  is started. Incidentally, in a case that an opening and closing operation of the right door  115  is performed, the stacking plate  52  is set in a state that the stacking plate  52  is positioned at a bottom of the accommodating cassette  51  which is shown in part (a) of  FIG.  2   . 
     In Step (hereinafter referred to as “S”)  201 , the control portion  80  instructs the state determination portion  81  to monitor an opening state of the right door  115  and determines whether the state determining portion  81  detects the opening state of the right door  115  or not based on the detected result of the right door sensor  116 . In a case that the state determining portion  81  determines that the opening state of the right door  115  is detected, the control portion  80  proceeds a process to S 202 , and in a case that the state determining portion  81  determines that the opening state of the right door  115  is not detected, the control portion  80  returns the process to S 201 . 
     In S 202 , the control portion  80  instructs the state determination portion  81  to monitor a closed state (an obstructed state) of the right door  115  and determines whether the state determining portion  81  detects the closed state (the obstructed state) of the right door  115  or not based on the detected result of the right door sensor  116 . In a case that the state determining portion  81  determines that the closed state of the right door  115  is detected, the control portion  80  determines that the opening and closing operation of the right door  115  has been performed and the replacing process of the feeding roller unit  20  has been completed, and proceeds a process to S 203 . On the hand, in a case that the state determining portion  81  determines that the closed state of the right door  115  is not detected, the control portion  80  determines that the right door  115  is in the opening state and the replacing process of the feeding roller unit  20  has not been completed, and returns the process to S 202 . 
     In S 203 , in order to determine whether the feeding roller unit  20  is mounted or not, the control portion  80  instructs the drive control portion  82  to drive the lift-up drive unit  70  and the drive control unit  82  drives the lift-up drive unit  70  in a lift-up direction for a predetermined time. Incidentally, the predetermined time refers to a time which requires to drive the lift-up drive unit  70  in the lift-up direction and move the feeding roller unit  20  to a state which is shown in part (a) of  FIG.  6   , in which the pickup roller  21  is possible to feed the sheet S which is stacked on the stacking plate  52  in an initial state. 
     In S 204 , the control portion  80  obtains a detecting state of the detecting flag  24  of the paper surface sensor  32  from the state determining portion  81 . And the control portion  80  determines whether the paper surface sensor  32  detects the detecting flag  24  or not (the light shielding state), based on the detected result of the paper surface sensor  32  which is obtained from the state determining portion  81 . Incidentally, as described above, in a case of the light transmitting state in which the paper surface sensor  32  detects the light from the light emitting portion, the paper sensor  32  does not detect the detecting flag  24 , and in a case of the light shielding state in which the paper surface sensor  32  does not detect the light from the light emitting portion, the paper sensor  32  detects the detecting flag  24 . In a case that the control portion  80  determines that the paper surface sensor  32  detects the detecting flag  24  (the light shielding state), the control portion  80  proceeds a process to S 205 , and in a case that the control portion  80  determines that the paper surface sensor  32  does not detect the detecting flag  24  (the light transmitting state), the control portion  80  proceeds the process to S 206 . In S 205 , the control portion  80  determines that the feeding roller unit  20  is mounted, however, it is not replaced with a new product of the feeding roller unit  20 , and returns a process to S 201 . As a specific example of proceeding to the process of S 205 , for example, there is a case that the feeding roller unit  20  is not replaced even though the opening and closing operation of the right door is performed after performing a jam process operation when the sheet S is retained on the conveying passage, etc. 
     In S 206 , the control portion  80  instructs the drive control portion  82  to drive the lift-up drive unit  70  in order to return the stacking plate  52  to the initial state, and the drive control portion  82  drives the lift-up drive unit  70  in a lift-down direction for a predetermined time. 
     In S 207 , since the paper surface sensor  32  does not detect the detecting flag  24 , the control  80  determines that either the feeding roller unit  20  is not mounted or a new product of the feeding roller unit  20  is mounted. Therefore, the control portion  80  instructs the drive control portion  82  to drive the feeding drive unit  60 , and the drive control portion  82  drives the feeding drive unit  60  for a certain period of time. For example, in a case that a new product of the feeding roller unit  20  is mounted, when the feeding drive unit  60  is driven, the feeding roller gear  26  of the feeding roller unit  20  is driven. And the pickup roller gear  25  and the pickup roller  21  are driven via the feeding roller gear  26 . Then, the detecting flag  24  moves from the state of the retracted position (part (a) of  FIG.  5   ) to the state of the projected position (part (b) of  FIG.  5   ). 
     In S 208 , the control portion  80  instructs the drive control portion  82  to drive the lift-up drive unit  70  in order to determine whether the feeding roller unit  20  is mounted, and the drive control portion  82  drives the lift-up drive unit  70  in the lift-up direction for a predetermined time. 
     In S 209 , the control portion  80  obtains a detecting state of the detecting flag  24  of the paper surface sensor  32  from the state determining portion  81 , and determines whether the paper surface sensor  32  detects the detecting flag  24  or not (the light shielding state), based on the detected result of the paper surface sensor  32  which is obtained. In a case that the control portion  80  determines that the paper surface sensor  32  detects the detecting flag  24  (the light shielding state), the control portion  80  proceeds a process to S 210 , and in a case that the control portion  80  determines that the paper surface sensor  32  does not detect the detecting flag  24  (the light transmitting state), the control portion  80  proceeds the process to S 211 . In S 210 , the control portion  80  determines that the feeding roller unit  20  has been replaced with a new product and returns a process to S 201 . 
     In S 211 , the control portion  80  determines that the feeding roller unit  20  is not mounted, and notifies it by displaying an indication that the feeding roller unit  20  is not mounted on a display portion of the operation portion  114 , and returns a process to S 201 . Incidentally, as an example of proceeding to S 211 , there is a case that the right door  115  is closed without remembering to mount the feeding roller unit  20  after removing the feeding roller unit  20  in order to replace the feeding roller unit  20 . 
     As described above, in the embodiment, the paper surface sensor  32  detects the position of the pickup roller  21  and detects a new product of the feeding roller unit  20  when the opening and closing operation of the right door  115  is performed. By detecting a new product of the feeding roller unit  20 , it is possible to automatically detect a replacement of a new product of the feeding roller unit  20  without increasing cost by using only one sensor. Further, a movement of the detecting flag  24  of the feeding roller unit  20  from the retracted position to the projected position is realized in a small space within the feeding roller unit  20  by using the convex portion  24   a  which interferes with the rubber material of the pickup roller  21  and the state holding spring  29 . 
     As described above, according to the embodiment, it is possible to automatically detect that the feeding roller is replaced with a new product. 
     Second Embodiment 
     In the first embodiment, the control, in which the uppermost sheet S which is stacked on the stacking plate abuts against the pickup roller and is set at the position which is possible to be fed by lift-up controlling the stacking plate of the sheet accommodating unit, is described. In a second embodiment, a control, in which the uppermost sheet S abuts against the pickup roller and is set at the position which is possible to be fed in a different configuration from the first embodiment, will be described. Incidentally, the image forming apparatus in the embodiment is provided with a same configuration as the image forming apparatus in the first embodiment, and a same reference numeral as in the first embodiment is used for the same apparatus and the same members, thereby, descriptions will be omitted here. 
     [Configuration of Sheet Feeding Apparatus] 
     Part (a) and part (b) of  FIG.  8    are sectional views showing a configuration of the sheet feeding apparatus  10  in the embodiment. Part (a) of  FIG.  8    shows a state in which the uppermost sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  is positioned at a feeding start position in which the uppermost sheet S abuts against the pickup roller  21 . On the other hand, part (b) of  FIG.  8    shows a state that the uppermost sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  is spaced away from the pickup roller  21 . Configurations of the feeding roller unit  20  and the separating roller unit  40  which are shown in part (a) and part (b) of  FIG.  8    is same as in the first embodiment. On the other hand, a feeding roller holding unit  30  in the embodiment is different from the feeding roller holding unit  30  in the first embodiment, in that the paper surface sensor  32  and the pick spring  31  are deleted and an abutting/spacing (contacting/separating) sensor  132  and a pickup roller abutting/spacing (contacting/separating) arm  133  are provided. Further, a sheet accommodating unit  50  in the embodiment is different from the sheet accommodating unit  50  in the first embodiment, in that it includes a sheet pressing spring  151  which presses the stacking plate  52  which stacks the sheet S in a direction of the pickup roller  21 . 
     The abutting/spacing sensor  132  is a photo interrupter which includes a light emitting portion which emits light and a light receiving portion which receives light which is emitted from the light emitting portion, similar to the paper surface sensor  32  in the first embodiment. The abutting/spacing sensor  132  detects a light shielding state in which the detecting flag  24  of the feeding roller unit  20  shields light from the light emitting portion or a light transmitting state in which the detecting flag  24  of the feeding roller unit  20  does not shield light from the light emitting portion and outputs the detected result of the control portion  80  to the state determining portion  81 . Further, the pickup roller abutting/spacing arm  133  (hereinafter referred to as an abutting/spacing arm  133 ) switches the pickup roller  21  to a position of abutting (contacting) state in which the uppermost sheet S which is stacked on the stacking plate  52  of the sheet accommodating unit  50  abuts against the pickup roller  21  or to a position of spacing (separating) state. The abutting/spacing arm  133  includes a rotational center coaxially with a feeding roller support member (not shown) which supports the feeding roller unit  20  and is rotatable. The feeding roller unit  20  also includes a rotational center coaxially with the feeding roller support member (not shown). That is, the feeding roller unit  20  and the abutting/spacing arm  133  includes a rotational center coaxially and are rotatable. 
     [Control Portion of Sheet feeding Apparatus] 
       FIG.  9    is a control block diagram showing a configuration of the control portion of the sheet feeding apparatus  10  in the embodiment. The control portion  80  which controls the sheet feeding apparatus  10  includes the state determining portion  81  which determines a state based on a signal which is output from each sensor, and the drive control portion  82  which controls each drive unit. The state determining portion  81  determines an abutting state or a spacing state of the pickup roller  21  according to the signal that the abutting/spacing sensor  132  outputs based on the light transmitting state or the light shielding state of the detecting flag  24  of the feeding roller unit  20 . Further, the state determining portion  81  determines an opened state or a closed state of the right door  115  based on the detected result of the right door sensor  116 . The drive control portion  82  controls a switching drive unit  170  which switches the abutting state or the spacing state between the pickup roller  21  and the sheet S by rotationally moving the feeding drive unit  60  which drives the feeding roller unit  20  which feeds the sheet S and the abutting/spacing arm  133 . The switching drive unit  170  is configured to branch the feeding drive unit  60  and to operate only when the feeding drive unit  60  is rotated in a reverse direction. The switching drive unit  170  switches a state of the abutting/spacing arm  133  to the abutting state in which the sheet S abuts against the pickup roller  21  or the spacing state by rotating a cam (not shown) which is connected to the abutting/spacing arm  133 . 
     [State Control of Pickup Roller] 
     Next, a positional control of the pickup roller  21  by switching the state of the abutting/spacing arm  133  and an abutting and spacing relationship with the uppermost sheet S which is stacked on the stacking plate  52  of the pickup roller  21  will be described. 
     First, a relationship of the light shielding state and the light transmitting state of the abutting/spacing sensor  132  by the detecting flag  24  and the abutting state and the spacing state between the uppermost sheet S and the pickup roller  21  will be described. Part (a) of  FIG.  8    shows a state in which the uppermost sheet S which is stacked on the stacking plate  52  abuts against the pickup roller  21 . At this time, the detecting flag  24  is positioned at a lower side of the abutting/spacing sensor  132  in the figure, and the abutting/spacing sensor  132  becomes the light transmitting state in which the light receiving portion receives light which is emitted from the light emitting portion. Therefore, based on the detected result of the detecting flag  24  from the abutting/spacing sensor  132 , the state determining portion  81  determines that the pickup roller  21  abuts against the uppermost sheet S which is stacked on the stacking plate  52 . On the other hand, part (b) of  FIG.  8    shows a state that the uppermost sheet S which is stacked on the stacking plate  52  and the pickup roller  21  are spaced. At this time, the detecting flag  24  is positioned in a state to shield the light which is emitted from the light emitting portion of the abutting/spacing sensor  132 . Therefore, based on the detected result of the detecting flag  24  from the abutting/spacing sensor  132 , the state determining portion  81  determines that the pickup roller  21  spaces away from the uppermost sheet S which is stacked on the stacking plate  52 . Incidentally, in a case that the feeding roller unit  20  is replaced and the feeding roller unit  20  is inserted into (mounted on) the feeding roller holding unit  30 , the feeding roller unit  20  becomes in a state which is shown in part (b) of  FIG.  8   . Incidentally, in part (b) of  FIG.  8   , since the abutting/spacing sensor  132  is in a state that the light is shielded by the detecting flag  24 , a state in a case that the feeding roller unit  20  which is not a new product is mounted is shown. In a case that a new product of the feeding roller unit  20  is mounted, since the detecting flag  24  is positioned in the retracted position, the abutting/spacing sensor  132  become the light transmitting state in which light is not shielded by the detecting flag  24 . 
     First, a control of switching a state of the pickup roller  21  from a state of spacing away from the uppermost sheet S to a state of abutting will be described. The control portion  80  instructs the drive control portion  82  to switch a state of the pickup roller  21  from a state of spacing away from the uppermost sheet S to a state of abutting. In order to shift the pickup roller  21  to the state of abutting against the uppermost sheet 
     S, the drive control portion  82  drives the switching drive unit  170  by rotating the feeding drive unit  60  in a reverse direction and rotates the abutting/spacing arm  133  in a direction B (a counterclockwise direction) in part (a) of  FIG.  8   . The abutting/spacing arm  133  and the roller holder  23  are connected with a certain amount of rattle, and when the abutting/spacing arm  133  abuts against the roller holder  23 , the roller holder  23  rotates in a direction B. On the other hand, the sheet S which is stacked on the stacking plate  52  is in a state of being lifted up in a direction toward the pickup roller  21  by the sheet pressing spring  151 . As the roller holder  23  rotates in the direction B, the pickup roller  21  also rotates in the direction B and abuts against the uppermost sheet S which is stacked on the stacking plate  52 . Thus, since a position of the detecting flag  24  is lowered in a direction toward the stacking plate  52 , a state of the abutting/spacing sensor  132  changes from the light shielding state, in which light is shielded by the detecting flag  24 , to the light transmitting state. And when the drive control portion  82  detects a change in the state of the abutting/spacing sensor  132  from the light shielding state to the light transmitting state, after the switching drive unit  170  is driven for a certain amount, the reverse rotation of the feeding drive unit  60  is stopped and a drive of the switching drive unit  170  is stopped. In this way, the control portion  80  moves the pickup roller  21  to a position in which the pickup roller  21  abuts against the sheet S and also moves the pickup roller  21  so that a proper pressing force is applied from the sheet pressing spring  151 . 
     Next, a control of switching a state of the pickup roller  21  from a state in which the pickup roller  21  abuts against the uppermost sheet S to a state in which the pickup roller  21  is spaced away from the uppermost sheet S will be described. The control portion  80  instructs the drive control portion  82  to switch the state of the pickup roller  21  from the state in which the pickup roller  21  abuts against the uppermost sheet S to the state in which the pickup roller  21  is spaced away from the uppermost sheet S. In order to shift the pickup roller  21  to the state of being spaced away from the uppermost sheet S, the drive control portion  82  drives the switching drive unit  170  by rotating the feeding drive unit  60  in the reverse direction and rotates the abutting/spacing arm  133  in a direction C (a clockwise direction) in part (a) of  FIG.  8   . When the rattle between the abutting/spacing arm  133  and the roller holder  23  is eliminated and the abutting/spacing arm  133  abuts against the roller holder  23 , the roller holder  23  rotates in the direction C. As the roller holder  23  rotates in the direction C, the pickup roller  21  also rotates in the direction C and is spaced away from the uppermost sheet S which is stacked on the stacking plate  52 . Thus, since a position of the detecting flag  24  is lifted up in a direction toward the feeding roller holding unit  30 , a state of the abutting/spacing sensor  132  changes from the light transmitting state, in which light is not shielded by the detecting flag  24 , to the light transmitting state. And when the drive control portion  82  detects the change in the state of the abutting/spacing sensor  132  from the light transmitting state to the light shielding state, after the switching drive unit  170  is driven for a certain amount, the reverse rotation of the feeding drive unit  60  is stopped and the drive of the switching drive unit  170  is stopped. While the switching drive unit  170  is driven for a certain amount, the stacking plate  52  which is pressed by the sheet pressing spring  151  abuts against a stopper (not shown) which is provided in the sheet accommodating unit  50  and cannot be lifted up any further. In this way, the control portion  80  finishes a spacing operation of the pickup roller  21  at a position in which the switching drive unit  170  drives for a certain amount from a state that the pickup roller  21  is spaced away from the sheet S. 
     [Detecting New Product of the Feeding Roller Unit  20 ] 
     Next, a method of detecting a new products of the feeding roller unit  20  in the embodiment will be described. Here, part (b) of  FIG.  8    is a view showing a state that the feeding roller unit  20  is replaced and the feeding roller unit  20  is inserted into (mounted on) the feeding roller holding unit  30 . Then, in part (b) of  FIG.  8   , the detecting flag  24  is moved to a state that the detecting flag  24  is at the projected position (part (b) of  FIG.  6   ), and since the abutting/spacing sensor  132  is set to the light shielding state, it is indicating a state that the feeding roller unit  20  which is not a new product has been mounted. On the other hand, in a case that the feeding roller unit  20  is a new product, since the detecting flag  24  is in a state of the retracted position (part (a) of  FIG.  6   ), the abutting/spacing sensor  132  is set to the light transmitting state. When the control portion  80  instructs the drive control portion  82  to drive the feeding drive unit  60 , and the drive control portion  82  drives the feeding drive unit  60  for a certain period of time, the detecting flag  24  shifts from a state of the retracted position (part (a) of  FIG.  6   ) to a state of the projected position (part (b) of  FIG.  6   ). As a result, the detecting flag  24  is set to a state which is shown in part (b) of  FIG.  8   , and the abutting/spacing sensor  132  is set to the light shielding state. In this way, the abutting/spacing sensor  132  in the embodiment and the paper surface sensor  32  in the first embodiment are same configurations with respect to the detecting flag  24 , and it is possible to detect a new product of the feeding roller unit  20  based on a flowchart in  FIG.  10    which will be described below. 
     [Control Sequence for Replacing Feeding Roller Unit] 
     Next, a control sequence which detects an operation of replacing the feeding roller unit  20  and detects a new product of the feeding roller unit  20  will be described.  FIG.  10    is a flowchart showing the control sequence of replacing the feeding roller unit  20 . A process which is shown in  FIG.  10    is executed by the control portion  80  when the printer  100  is turned on and the control portion  80  is started. 
     In S 301 , the control portion  80  instructs the state determining portion  81  to monitor an opening state of the right door  115 , and determines whether the state determining portion  81  detects the opening state of the right door  115  or not based on the detected result of the right door sensor  116 . In a case that the control portion  80  determines that the state determining portion  81  detects the opening state of the right door  115 , the control portion  80  proceeds a process to S 302 , and in a case that the control portion  80  determines that the state determining portion  81  does not detect the opening state of the right door  115 , the control portion  80  returns the process to S 301 . 
     In S 302 , the control portion  80  instructs the state determining portion  81  to monitor a closed state (an obstructed state) of the right door  115 , and determines whether the state determining portion  81  detects the closed state (the obstructed state) of the right door  115  or not based on the detected result of the right door sensor  116 . In a case that the control portion  80  determines that the state determining portion  81  detects the closed state of the right door  115 , the control portion  80  determines that the opening and closing operation of the right door  115  is preformed and the process of replacing the feeding roller unit  20  is finished and proceeds a process to S 303 . On the other hand, in a case that the control portion  80  determines that the state determining portion  81  does not detect the closed state of the right door  115 , the control portion  80  determines that the right door  115  is in the opening state and the process of replacing the feeding roller unit  20  is not finished and returns the process to S 302 . 
     In S 303 , the control portion  80  obtains a detecting state of the detecting flag  24  of the abutting/spacing sensor  132  from the state determining portion  81 . Incidentally, as described above, in a case of the light transmitting state in which the abutting/spacing sensor  132  detects the light from the light emitting portion, the abutting/spacing sensor  132  does not detect the detecting flag  24 , and in a case of the light shielding state in which the abutting/spacing sensor  132  does not detect the light from the light emitting portion, the abutting/spacing sensor  132  detects the detecting flag  24 . 
     In S 304 , the control portion  80  determines whether the abutting/spacing sensor  132  detects the detecting flag  24  or not (the light shielding state), based on the detected result of the abutting/spacing sensor  132  which is obtained from the state determining portion  81 . In a case that the control portion  80  determines that the abutting/spacing sensor  132  detects the detecting flag  24  (the light shielding state), the control portion  80  proceeds a process to S 305 , and in a case that the control portion  80  determines that the abutting/spacing sensor  132  does not detect the detecting flag  24  (the light transmitting state), the control portion  80  proceeds the process to S 306 . In S 305 , the control portion  80  determines that the feeding roller unit  20  is mounted, however, it is not replaced with a new product of the feeding roller unit  20 , and returns a process to S 301 . 
     In S 306 , since the abutting/spacing sensor  132  does not detect the detecting flag  24 , the control  80  determines that either the feeding roller unit  20  is not mounted or a new product of the feeding roller unit  20  is mounted. Therefore, the control portion  80  instructs the drive control portion  82  to drive the feeding drive unit  60 , and the drive control portion  82  drives the feeding drive unit  60  for a certain period of time. For example, in a case that a new product of the feeding roller unit  20  is mounted (part (a) of  FIG.  6   ), when the feeding drive unit  60  is driven, the feeding roller gear  26  of the feeding roller unit  20  is driven. And the pickup roller gear  25  and the pickup roller  21  are driven via the feeding roller gear  26 . Then, the detecting flag  24  moves from the state of the retracted position (part (a) of  FIG.  6   ) to the state of the projected position (part (b) of  FIG.  6   ) and shields light of the abutting/spacing sensor  132 , and the abutting/spacing sensor  132  detects the detecting flag  24 . 
     In S 307 , the control portion  80  obtains a detecting state of the detecting flag  24  of the abutting/spacing sensor  132  from the state determining portion  81 , and determines whether the abutting/spacing sensor  132  detects the detecting flag  24  or not (the light shielding state), based on the detected result which is obtained. In a case that the control portion  80  determines that the abutting/spacing sensor  132  detects the detecting flag  24  (the light shielding state), the control portion  80  proceeds a process to S 308 , and in a case that the control portion  80  determines that the abutting/spacing sensor  132  does not detect the detecting flag  24  (the light transmitting state), the control portion  80  proceeds the process to S 309 . In S 308 , the control portion  80  determines that the feeding roller unit  20  has been replaced with a new product and returns a process to S 301 . 
     In S 309 , the control portion  80  determines that the feeding roller unit  20  is not mounted, and notifies it by displaying an indication that the feeding roller unit  20  is not mounted on a display portion of the operation portion  114 , and returns a process to S 301 . Incidentally, as an example of proceeding to S 309 , there is a case that the right door  115  is closed without remembering to mount the feeding roller unit  20  after removing the feeding roller unit  20  in order to replace the feeding roller unit  20 . 
     As described above, in the embodiment, by detecting the detecting flag  24  with the abutting/spacing sensor  132 , the abutting/spacing sensor  132  detects the position of the pickup roller  21  and detects a new product of the feeding roller unit  20  when the opening and closing operation of the right door  115  is performed. By detecting a state of the detecting flag  24  while detecting a new product of the feeding roller unit  20 , it is possible to automatically detect a replacement of a new product of the feeding roller unit  20  without increasing cost by using only one sensor. Further, a movement of the detecting flag  24  of the feeding roller unit  20  from the retracted position to the projected position is realized in a small space within the feeding roller unit  20  by using the convex portion  24   a  which interferes with the rubber material of the pickup roller  21  and the state holding spring  29 . 
     Incidentally, in the embodiment, the switching drive unit  170  controls the abutting/spacing arm  133  by using a cam (not shown), however, for example, it is also possible to control a position by controlling a rack gear which is connected to the lift-up drive unit  70  in the first embodiment. Further, the sheet feeding apparatus  10  in the embodiment may also be provided with both of the lift-up drive unit  70  in the first embodiment and the switching drive unit  170  in the embodiment. Furthermore, the sheet feeding apparatus  10  which is provided with a laser beam printer is described as an example, however, an image forming apparatus to which the present invention is applied is not limited to this, and, for example, printers and copiers of other printing methods such as inkjet printers and copiers may also be applied 
     As described above, according to the embodiment, it is possible to automatically detect that a feeding roller has been replaced with a new product. 
     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. 2021-189171 filed on Nov. 22, 2021, which is hereby incorporated by reference herein in its entirety.