Patent Publication Number: US-9889684-B2

Title: Image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2015-233836, filed on Nov. 30, 2015 in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an image forming apparatus. 
     Description of the Related Art 
     The image forming apparatuses are known which include both a rolled sheet feeder and a manually-inserted cut sheet feeder. Such image forming apparatuses are also equipped with a conveyance path and a sheet feeding roller exclusively used for manually-inserted cut sheets. 
     In one example of the above-described image forming apparatuses, a cut sheet is manually inserted until the leading edge of the cut sheet strikes against a switching member held in a striking position and is automatically conveyed thereafter. 
     This image forming apparatus has a drawback that a time-wasting complicated operation is required to transfer the switching member to the striking position, when the sheet is set at a wrong position due to the occurrence of skew, etc., and needs to be reset at a proper position. 
     SUMMARY 
     In accordance with some embodiments of the present invention, an image forming apparatus is provided. The image forming apparatus includes a feeder, an image former, an ejector, a conveyance path, a manual feeder, a manual conveyance path, a conveyer, a drive source, a switching member, a drive force transmitter, a slip rotator, a clutch, a set position detector, and a first controller. The feeder feeds a recording medium. The image former forms an image on the recording medium. The ejector ejects the recording medium having the image thereon. The conveyance path guides the recording medium fed from the feeder to the image former. The manual feeder feeds a manually-inserted recording medium from the ejector to the manual conveyance path. The manual conveyance path guides the manually-inserted recording medium fed from the manual feeder, to the image former via a downstream side of the conveyance path in an ejection direction. The conveyer conveys the recording medium fed from the feeder to the image former via the conveyance path and conveys the manually-inserted recording medium fed from the manual feeder to the image former via the manual conveyance path. The conveyer is rotatable either normally or reversely. The drive source drives the conveyer to rotate either normally or reversely. The switching member is a claw-like member disposed on a shaft. The switching member is swingable between an evacuation position and a striking position as the shaft rotates. The switching member in the evacuation position is evacuated from the manual conveyance path to allow the manually-inserted recording medium to advance. The switching member in the striking position is entered into the manual conveyance path to allow a leading edge of the manually-inserted recording medium to strike against the switching member. The switching member is configured to switch from the striking position to the evacuation position as the conveyer reversely rotates. The drive force transmitter transmits a drive force from the drive source to both the conveyer and the shaft. The slip rotator gives a rotational load to the shaft. The clutch is coupled to the drive force transmitter. The clutch is configured to transmit the drive force to the shaft when being connected, and to hold the switching member at the striking position or the evacuation position when being disconnected owing to the rotational load from the slip rotator. The set position detector detects whether a trailing edge of the manually-inserted recording medium is positioned at a set position or not relative to the image former. The first controller controls the drive source and the clutch such that the conveyer normally rotates to convey the manually-inserted recording medium from the manual conveyance path to the ejector and that the switching member swings from the evacuation position to the striking position, based on a signal indicating that the set position is wrong, transmitted from the set position detector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant advantages thereof will he readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an image forming apparatus according to a first embodiment of the present invention in which a pressure releasing lever is in a pressurizing state; 
         FIG. 2  is a perspective view of the image forming apparatus according to the first embodiment of the present invention in which the pressure releasing lever is in a depressurizing state; 
         FIG. 3  is a side of the image forming apparatus illustrated in  FIG. 1 ; 
         FIG. 4  is a perspective view of a registration roller and periphery thereof included in the image forming apparatus illustrated in  FIGS. 1 to 3 ; 
         FIG. 5  is a partial side view of the image forming apparatus illustrated in  FIGS. 1 to 3  in which a rolled sheet is conveyed; 
         FIG. 6  is a partial side view of the image forming apparatus illustrated in  FIGS. 1 to 3  in which a cut sheet is manually inserted; 
         FIG. 7  is a side view of the image forming apparatus illustrated in  FIGS. 1 to 3  in which a manually-inserted cut sheet is being fed to a set position; 
         FIG. 8  is a side view of the image forming apparatus illustrated in  FIGS. 1 to 3  in which an image is being printed on a manually-inserted cut sheet; 
         FIG. 9A  is a plan view of a major part of a driver included in the image forming apparatus illustrated in  FIGS. 1 to 3 ;  FIG. 9B  is an illustration of a striking position of a switching member included in the image forming apparatus illustrated in  FIGS. 1 to 3 ;  FIG. 9C  is an illustration of an evacuation position of the switching member; 
         FIG. 10  is a right side view of the driver illustrated in  FIG. 9A ; 
         FIG. 11  is a block diagram of a controller in the image forming apparatus illustrated in  FIG. 1 ; 
         FIG. 12  is a flowchart of a manual feeding preparation operation for a related-art image forming apparatus; 
         FIG. 13  is a flowchart of a manual feeding preparation operation for the image forming apparatus according to the first embodiment; 
         FIGS. 14A and 14B  are side views of an image forming apparatus according to a first modification in a cut sheet ejection operation; 
         FIG. 15  is a flowchart of a manual feeding preparation operation for an image forming apparatus according to a second modification; and 
         FIGS. 16A to 16C  are side views of an image forming apparatus according to a third modification. 
     
    
    
     The accompanying drawings are intended to depict example embodiments of the present invention and should not be interpreted to limit the scope thereof The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. 
     DETAILED DESCRIPTION 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Embodiments of the present invention are described in detail below with reference to accompanying drawings. In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve a similar result. 
     For the sake of simplicity, the same reference number will he given to identical constituent elements such as parts and materials having the same functions and redundant descriptions thereof omitted unless otherwise stated. 
     In accordance with some embodiments of the present invention, an image forming apparatus is provided which is easy to reset the position of a manually-inserted recording medium. 
     Embodiment 1 
     A first embodiment of the present invention is described below with reference to  FIGS. 1 to 3 .  FIG. 1  is a perspective view of an image forming apparatus according to a first embodiment of the present invention in which a pressure releasing lever is in a pressurizing state.  FIG. 2  is a perspective view of the image forming apparatus according to the first embodiment of the present invention in which the pressure releasing lever is in a depressurizing state.  FIG. 3  is a cross-sectional side view of the image forming apparatus illustrated in  FIG. 1 . 
     An image forming apparatus  1  illustrated in  FIGS. 1 to 3  is an inkjet recording apparatus, more specifically, an inkjet printer capable of discharging ink droplets onto a recording medium to print an image on the recording medium according to image data. 
     Referring to  FIGS. 1 to 3 , the image forming apparatus  1  includes an apparatus body  1 A. Directions X and Y represent a front-back direction (sub-scanning direction) and a width direction (main scanning direction), respectively, of the apparatus body  1 A. The directions X and Y are perpendicular to each other. A direction Z represents an upside-downside direction (height/vertical direction) of the apparatus body  1 A. The direction Z is perpendicular to both the directions X and Y. With respect to the front-back direction X, F and R respectively indicate front and rear sides of the apparatus body  1 A. With respect to the upside-downside direction Z, U and D respectively indicate upside and downside of the apparatus body  1 A. 
     The image forming apparatus  1  is a compact apparatus which requires no large installation space. The image forming apparatus  1  is capable of feeding manually-inserted cut sheets or long sheets (a long sheet refers to a part of a rolled sheet) without causing skew or paper jam. The image forming apparatus  1  is configured such that long sheets easily insertable. Moreover, the image forming apparatus  1  is configured such that a registration roller and a pressure roller are contactable with and separable from each other by a manual operation. Compared to high-end image forming apparatuses in which the registration roller and the pressure roller are automatically contactable with and separable from each other, or in which the pressing force is variable in accordance with the sheet size, the image forming apparatus  1  includes a lesser number of components with a lower cost. 
     Referring to  FIGS. 1 to 3 , the image forming apparatus  1  includes an image former  2  on an upper part and a feeder  3  on a lower part. The feeder  3  includes spool bearing stands  101   a  and  101   b.    
     The image former  2  forms an image on a recording medium by means of inkjet recording. The recording medium may be either a long sheet  10  or a cut sheet. The image forming apparatus  1  is a serial type inkjet recording apparatus. 
     Referring to  FIGS. 1 to 3 , the image forming apparatus  1  includes an ejector  4  to eject the recording medium after the image former  2  has formed an image thereon. The ejector  4  is disposed on the front side F of the apparatus body  1 A. The ejector  4  includes a platen guide plate  16   a  and an ejection port  4   a  disposed above the platen guide plate  16   a.  The platen guide plate  16   a  receives and guides the recording medium to be ejected to the ejection port  4   a.  The ejection port  4   a  ejects the recording medium. 
     The ejector  4  further includes a front cover  12  that is openable and closable, to allow a user to manually insert a recording medium or to remove paper jam. The front cover  12  is swingable about a hinge disposed on an upper part of the front side F of the apparatus body  1 A, so that the lower part of the front cover  12  is openable and closable. A front cover open sensor  13  is disposed on the apparatus body  1 A in proximity to the hinge of the front cover  12 . The front cover open sensor  13  detects whether the front cover  12  is in an open state or a closed state. The front cover open sensor  13  is turned on when the front cover  12  is opened by a user. 
     The feeder  3  is capable of feeding the sheet  10 , in the form of a long sheet, drawn from a sheet roll  10   a  or  10   b  stored in the spool bearing stand  101   a  or  101   b,  respectively. The spool bearing stands  101   a  and  101   b  are aligned in the upside-downside (vertical) direction Z of the apparatus body  1 A. The spool beating stands  101   a  and  101   b  store the sheet rolls  10   a  and  10   b , respectively, so that the sheet  10  is drawable from the sheet roll  10   a  or  10   b.    
     The sheet roll  10   a  on the upper side (hereinafter “upper sheet roll  10   a ”) and the sheet roll  10   b  on the lower side (hereinafter “lower sheet roll  10   b ”) are rotatabiy supported by the spool bearing stands  101   a  and  101   b,  respectively. The sheet  10  is selectively drawable from the upper sheet roll  10   a  or the lower sheet roll  101   b . Referring to  FIGS. 1 and 3 , the image forming apparatus  1  further includes sheet roll guides  102   a  and  102   b,  a stand  103  disposed on a lower part of the apparatus body  1 A, and spool flanges  104 . 
     The upper sheet roll  10   a  and the lower sheet roll  10   b  are stored at a lower end part and a front surface side of the apparatus body  1 A. A front surface  1 F of the apparatus body  1 A has openings  7  and  8  through which the upper sheet roll  10   a  and the lower sheet roll  10   b , respectively, are replaceable. 
     At the periphery of the spool bearing stands  101   a  and  101   b,  a drive motor and a drive force transmitter are provided, capable of drawing out the sheet  10  from the upper sheet roll  10   a  or the lower sheet roll  10   b,  conveying the sheet  10 , and rewinding the conveyed sheet  10 . 
     In place of the above-described spool bearing stands  101   a  and  101   b , flange hearing stands may support the sheet rolls  10   a  and  10   b  so that the sheet  10 , in the form of a long sheet, is drawable therefrom. 
     The image former  2  includes a guide rod  18  and a guide rail  19  each supported by side plates disposed on the left and right sides of the apparatus body  1 A in the width direction Y. The guide rod  18  and the guide rail  19  moveably hold a carriage  20  in the main scanning direction Y. 
     The carriage  20  includes liquid recording heads  15  for discharging black, yellow, magenta, and cyan ink droplets, respectively. Each liquid recording head  15  integrally includes a sub tank for retaining an ink to be supplied thereto. 
     A main scanning mechanism that moves the carriage  20  in the main scanning direction Y includes a drive motor  21 , a drive pulley  22 , a driven pulley  23 , and a belt  24 . The drive motor  21  is disposed on one side (left side in  FIG. 1 ) in the main scanning direction Y. The drive pulley  22  is coupled to the output shaft of the drive motor  21  to be rotary-driven thereby. The driven pulley  23  is disposed on the other side (right side in  FIG. 1 ) in the main scanning direction Y. The belt  24  is stretched between the drive pulley  22  and the driven pulley  23 . 
     The driven pulley  23  is pulled by a tension spring in a direction away from the drive pulley  22 . 
     As illustrated in  FIG. 3 , a platen  16  is disposed below the liquid recording heads  15  of the carriage  20 , covering over a recording area extending in the main scanning direction Y of the carriage  20 . The platen  16  serves as a recording medium guide for guiding a rolled sheet or a manually-inserted sheet. The platen  16  has a large number of pores for sucking air. The platen  16  includes the platen guide plate  16   a  and a suction fan  17  disposed below the platen guide plate  16   a.    
     As illustrated in  FIG. 3 , an encoder sheet  28  is disposed between the side plates along the main scanning direction Y of the carriage  20 , for detecting the position of the carriage  20  in the main scanning direction Y. An encoder sensor  29  for reading the encoder sheet  28  is mounted on the carriage  20 . As the encoder sensor  29  reads the encoder sheet  28 , the position of the carriage  20  in the main scanning direction Y is detected. 
     As illustrated in  FIG. 3 , the carriage  20  includes a sheet end detection sensor  30  for detecting an end of the recording medium. The sheet end detection sensor  30  includes a reflective photosensor. As the carriage  20  moves to a position corresponding to the right end of the sheet  10  in the main scanning direction Y, the sheet end detection sensor  30  detects the right end of the sheet  10  drawn from the sheet roll  10   a  or the sheet roll  10   b.  The carriage  20  then moves to a position corresponding to the left end of the sheet  10  in the main scanning direction Y, and the sheet end detection sensor  30  detects the left end of the sheet  10 . The size of the sheet  10  is determined from the difference between the values detected by the sheet end detection sensor  30  at the right and left ends of the sheet  10 , corresponding to the positions of the right and left ends of the sheet  10  in the main scanning direction Y read by the encoder sensor  29 . 
     A sheet conveying device is described below with reference to  FIGS. 3 and 4 .  FIG. 4  is a perspective view of a registration roller and periphery thereof, composing a sheet conveying device, included in the image forming apparatus  1  illustrated in  FIGS. 1 to 3 . The sheet  10  drawn from the sheet roll  10   a  or the sheet roll  10   b  is conveyed by the sheet conveying device illustrated in  FIG. 4  within the recording area in the main scanning region of the carriage  20 . 
     Referring to  FIG. 4 , the sheet conveying device includes a registration roller  34 , multiple pressure rollers  35 , a drive motor  38 , an encoder sheet  37 , and an encoder sensor  36 . 
     The registration roller  34  and each of the pressure rollers  35  form a pair of holding-conveying members contactable with and separable from each other, serving as a conveyer. The registration roller  34  is a drive roller rotary-driven by the drive motor  38 . The pressure rollers  35  are driven rollers driven by the registration roller  34 . The registration roller  34  and the pressure rollers  35  are supported by inner side plates so as to be rotatable either normally or reversely. 
     A motor pulley  38   a  is disposed on the output shaft of the drive motor  38 . A registration large-diameter pulley  52  is secured to one end of the registration roller  34 . A timing belt  43  is wound around the motor pulley  38   a  and the registration large-diameter pulley  52 . A rotation or drive force of the drive motor  38  is transmitted to the registration roller  34  via the timing belt  43 . Each of the motor pulley  38   a  and the registration large-diameter pulley  52 , as well as the later-described other pulleys wound around another timing belt, is a toothed pulley (timing pulley). 
     The drive motor  38  may include a DC motor. The drive motor  38  serves as a single drive source for driving the conveyer to rotate either normally or reversely. The drive motor  38  is secured to an inner side plate fixed to the apparatus body  1 A. 
     The pressure rollers  35  are rotatably supported by a common shaft disposed at an end of at arm-like pressure roller bracket  53 . The pressure rollers  35  are divided and skewered rollers. Each pressure roller bracket  53  supports two pressure rollers  35 . The pressure roller bracket  53  includes a wire spring for applying a pressing force (biasing force) in a direction in which the pressure rollers  35  is pressed against the registration roller  34 . 
     As illustrated in  FIG. 4 , the pressure roller bracket  53  is swingably mounted on a shaft  53   a  supported by the apparatus body  1 A, at the opposite end from the end supporting the pressure rollers  35 . The pressure rollers  35  are swingable about the shaft  53   a  via the pressure roller bracket  53  between a pressurizing position and a depressurizing position. At the pressurizing position, the pressure rollers  35  are pressed against the registration roller  34 . The depressurizing position is a position separated away from the pressurizing position. 
     As illustrated in  FIGS. 1 and 2 , a pressure releasing lever  54  is mounted on the shaft  53   a  of the pressure roller bracket  53 . The pressure rollers  35  are switchable between the pressurizing position and the depressurizing position by manually operating the pressure releasing lever  54 . The pressure releasing lever  54  is disposed inside the apparatus body  1 A, and therefore operable when the front cover  12  is opened. When the pressure releasing lever  54  is pushed down, as illustrated in  FIG. 1 , the pressure rollers  35  occupy the pressurizing position. When the pressure releasing lever  54  is lifted up, as illustrated in  FIG. 2 , the pressure rollers  35  occupy the depressurizing position. 
     The pressure releasing lever  54  may be replaced with another pressure releaser, such as a pressure releasing mechanism and a link mechanism having an operation lever. 
     The encoder sheet  37  is a disk-like member disposed coaxially with the registration roller  34 . The encoder sensor  36  includes a transmissive photosensor having a light emitting part and a light receiving part. The encoder sensor  36  is secured to an inner side plate so as to grip the outer peripheral edge of the encoder sheet  37 . 
     On one end side (right side in  FIG. 1 ) of the main scanning region of the carriage  20 , a maintenance unit  25  is disposed for maintaining the liquid recording heads  15  of the carriage  20 . In addition, a main cartridge  26  is detachably mounted on the apparatus body  1 A. The main cartridge  26  stores inks to be supplied to the sub tanks of the liquid recording heads  15 . 
     A cutter  27  is disposed in the vicinity of the ejection port  4   a  of the ejector  4  in the image former  2 . The cutter  27  cuts the sheet  10  into a piece having a predetermined length. The cutter  27  is secured to a wire or timing belt wound around multiple pulleys, one of which being coupled to a cutter drive motor. As the cutter drive motor moves in the main scanning direction Y, the cutter  27  cuts the sheet  10  into a piece having a predetermined length. 
     A sheet feeding and conveying operations and an image forming operation when the feeder  3  feeds the sheet  10  are described below with reference to  FIGS. 1 to 4 . As illustrated in  FIG. 3 , in the feeder  3 , the sheet  10  drawn from the sheet roll  10   a  or the sheet roll  10   b  is held and conveyed by a conveyance roller pair  9   a  or  9   b,  the registration roller  34 , and the pressure rollers  35 . The conveyance roller pairs  9   a  and  9   b  are disposed upstream from a conveyance path  5 . The sheet  10  is smoothly conveyed through the conveyance path  5  while being guided by a driven guide roller  48  disposed at a curved portion of the conveyance path  5 , to be described in detail later with reference to  FIG. 5 , etc. 
     The conveyance path  5  is formed of sheet conveyance guide members  201  and  202 . The sheet  10  passes through the conveyance path  5  to reach the image former  2 . In the image former  2 , the liquid recording heads  15  discharge colored liquid droplets onto the sheet  10  to form an image on the sheet  10  in accordance with image data. A pre-registration sensor  49  is disposed in the vicinity of the conveyance path  5 , to be described in detail later with reference to  FIG. 5 , etc. The pre-registration sensor  49  includes a reflective photosensor. The pre-registration sensor  49  detects a leading or trailing edge of the sheet  10  pass through the conveyance path  5 , in other words, detects the presence of the sheet  10  within the conveyance path  5 . After an image has been formed on the sheet  10 , the cutter  27  moves in the main scanning direction Y and cuts the sheet  10  into a piece having a predetermined length. The cut piece of the sheet  10  is ejected onto an ejection tray. 
     While the image former  2  is performing an image forming operation, the sheet  10  is intermittently conveyed in a direction indicated by arrow Xa (hereinafter “ejection direction Xa”) along the sub-scanning direction (i.e., the front-back direction X). The sub-scanning direction X is perpendicular to the main scanning direction Y along which the carriage  20  moves. The amount of conveyance is controlled by a controller  110  based on information obtained by the encoder sensor  36  by reading the encoder sheet  37  coaxially disposed with the registration roller  34 . 
     A manual feeder and a manual conveyance path are described below with reference to  FIGS. 1 to 3, 5, and 6 .  FIG. 5  is a partial side view of the image forming apparatus  1  in which a rolled sheet is conveyed.  FIG. 6  is a partial side view of the image forming apparatus  1  in which a cut sheet is manually inserted. 
     As illustrated in  FIGS. 3 and 6 , the image forming apparatus  1  includes a manual feeder  6 . The manual feeder  6  allows a recording medium, such as a cut sheet  50  indicated by a broken line in  FIG. 6 , to be inserted through the ejector  4  toward the image former  2 . The manual feeder  6  partially combines the function of the ejector  4 . 
     As illustrated in  FIGS. 3, 5, and 6 , the image forming apparatus  1  includes a manual conveyance path  11  to guide the cut sheet  50  manually inserted from the manual feeder  6  to the image former  2  via a downstream side of the conveyance path  5  in the ejection direction Xa. The manual conveyance path  11  is formed of manual sheet conveyance guide plates  251  and  252 . 
     The conveyance path  5  and the manual conveyance path  11  join together on a downstream side of the conveyance path  5 , thereby forming a joined conveyance path  14 . The joined conveyance pad  14  extends from the joined position of the conveyance path  5  with the manual conveyance path  11  to the ejection port  4   a  of the ejector  4 . 
     As described above, the conveyer, including the registration roller  34  and the pressure rollers  35 , has a function of conveying the sheet  10  fed from the feeder  3  to the image former  2  via the conveyance path  5 . At the same time, the conveyer has another function of conveying the cut sheet  50  manually inserted from the manual feeder  6  to the image former  2  via the manual conveyance path  11 , while being rotatable either normally or reversely. 
     As illustrated in  FIGS. 5 and 6 , a switching member  40  is disposed on a downstream side of the manual conveyance path  11  relative to an insertion direction Xb of the cut sheet  50 . The switching member  40  is a claw-like member disposed on the shaft  41 . The switching member  40  is swingable as the shaft  41  rotates. The switching member  40  is swingable between an evacuation position and a striking position. When in the evacuation position, as illustrated in  FIG. 7 , the switching member  40  is evacuated from the manual conveyance path  11  to allow the manually-inserted cut sheet  50  to advance. When in the striking position, as illustrated in  FIG. 6 , the switching member  40  is entered into the manual conveyance path  11  to allow a leading edge  50   a  of the cut sheet  50  to strike against the switching member  40 . 
     In particular, multiple switching members  40  are disposed on the shaft  41  in a longitudinal direction in a cyclic manner within a region where the cut sheet  50  passes within the manual conveyance path  11 . When the switching member  40  is in the striking position, as illustrated in  FIG. 6 , the cut sheet  50  is properly set without causing bending on the leading edge  50   a.  The manual sheet conveyance guide plates  251  and  252  have multiple cutouts so that the multiple switching members  40  disposed on the shaft  41  in the longitudinal direction become movable and swingable within the manual conveyance path  11 . 
     A manual sensor  47  is disposed downstream from the switching member  40  on the manual conveyance path  11  relative to the ejection direction Xa. The manual sensor  47  detects presence of the manually-inserted cut sheet  50 . The manual sensor  47  includes a reflective photosensor. 
     A conveyance operation is described below with reference to  FIGS. 5 to 8 .  FIG. 7  is a side view of the image forming apparatus  1  in which a manually-inserted cut sheet is being fed to a set position (i.e., a print start position, to be described in detail later).  FIG. 8  is a side view of the image forming apparatus  1  in which an image is being printed on the manually-inserted cut sheet. 
     First, a conveyance operation for conveying the sheet  10  drawn from the sheet roll  10   a  or  10   b  (hereinafter simply “the sheet roll”) is described with reference to  FIG. 5 . The sheet  10  drawn from the sheet roll, indicated by a broken line, is held and conveyed by the registration roller  34  and the pressure rollers  35  in the ejection direction Xa, while the registration roller  34  is normally rotating in the direction indicated by arrow in  FIG. 5 . The liquid recording heads  15  of the carriage  20  print an image on the sheet  10  being conveyed. At this time, the switching member  40  is in the striking position to block the manual conveyance path  11 , without exerting influence on conveyance of the sheet  10  within the conveyance path  5 . 
     A manual insertion-feeding operation for cut sheets is described with reference to  FIG. 6 . 
     During the manual insertion-feeding operation, the sheet  10  drawn from the sheet roll should be temporarily evacuated from the joined position of the conveyance path  5  with the manual conveyance path  11  to an upstream side thereof. Thus, the registration roller  34  is reversely rotated and the sheet roll is wound back, to evacuate a leading edge  10 A of the sheet  10  to a position near the pre-registration sensor  49 . 
     Next, the front cover  12  is opened, as illustrated in  FIG. 2 , and the pressure releasing lever  54  is operated in the direction indicated by arrow in in  FIG. 2 , so that the pressure rollers  35  are separated upward from the registration roller  34  to he held in the depressurizing position. The cut sheet  50 , indicated by a broken line in  FIG. 6 , is then inserted from the ejection port  4   a  (illustrated in  FIG. 2 ) until the leading edge  50   a  of the cut sheet  50  strikes against the switching member  40  held in the striking position. At this time, the switching member  40  held in the striking position properly sets the cut sheet  50  without bending it. 
     Whether or not the leading edge  50   a  of the cut sheet  50  has struck against the switching member  40  is detected by the manual sensor  47 . It is preferable that the inserted cut sheet  50  is prevented from shifting until the pressure rollers  35  are switched to the pressurizing state, as illustrated in  FIG. 1 , by operating the pressure releasing lever  54 . Specifically, it is preferable that the suction fan  17  of the platen  16  is put into operation so that the cut sheet  50  is sucked by the suction fan  17  and held on the platen  16 . It is preferable that the manual conveyance path  11  (i.e., the gap between the manual sheet conveyance guide plates  251  and  252 ) is made narrower toward the switching member  40  so that the leading edge  50   a  of each cut sheet  50  is aligned. 
     Next, after the pressure releasing lever  54  is operated such that the pressure rollers  35  are pressed against the registration roller  34 , the registration roller  34  is reversely rotated in a direction indicated by arrow in  FIG. 7 . Thus, a trailing edge  50   b  of the cut sheet  50  is automatically conveyed to the print start position. (The trailing edge  50   b  switches to a leading edge when an image is being printed on the cut sheet  50 .) At this time, the set position of the cut sheet  50  is checked. As the registration roller  34  is reversely rotated while an electromagnetic clutch, to be described later referring to  FIG. 9A , is connected, the cut sheet  50  having struck against the switching member  40  is conveyed in a conveyance direction Xc. At the same time, the switching member  40  starts swinging and shifts to the evacuation position. 
     When the gear ratio is set such that the rotation speed of the switching member  40  is slower than the sheet conveyance speed, the cut sheet  50  will be pressed against the switching member  40  and damaged or bent thereby. To prevent this phenomenon, the gear ratio is set such that the circumferential speed of the switching member  40  at the position where the leading edge  50   a  of the cut sheet  50  strikes thereon is faster than the sheet conveyance speed of the registration roller  34 . In this case, the switching member  40  can be moved to the evacuation position without the cut sheet  50  being pressed against the switching member  40 , and the cut sheet  50  can be normally conveyed. 
     As illustrated in  FIG. 8 , the switching member  40  is held at the evacuation position when an image is being printed on the manually-inserted cut sheet  50 . The switching member  40  exerts no influence on the printing operation. As illustrated in  FIG. 8 , while the cut sheet  50  is being conveyed within the manual conveyance path  11  in the ejection direction Xa by the registration roller  34  normally rotating and the pressure rollers  35 , the liquid recording head  15  print an image on the cut sheet  50 . 
     A driver for driving the conveyer is described below with reference to  FIGS. 9A to 9C and 10 .  FIG. 9A  is a plan view of a major part of a driver.  FIG. 9B  is an illustration of the striking position of the switching member  40 .  FIG. 9C  is an illustration of the evacuation position of the switching member  40 .  FIG. 10  is a right side view of the driver illustrated in  FIG. 9A . 
     Referring to  FIG. 9A , numerals  32  and  33  respectively denote the conveyer and the driver. The driver  33  includes the sheet conveying device illustrated in  FIG. 4 , the drive motor  38 , the encoder sensor  36 , the encoder sheet  37 , the timing belt  43 , another timing belt  44 , an electromagnetic clutch  42 , a clutch gear  45 , a gear  51 , a registration small-diameter pulley  55 , a transmission shaft  62 , a transmission shaft pulley  63 , a gear  67 , springs  60  and  66 , disc members  87  and  91 , a filler  64 , a position detection sensor  65 , a spring pin  88 , and a screw pin  89 . 
     A drive force transmitter, for transmitting a drive force of the drive motor  38  to the conveyer (i.e., the registration roller  34  and the pressure rollers  35 ) and to the shaft  41  of the switching member  40 , is described below with reference to  FIGS. 9A to 9C and 10 . The drive force transmitter includes: the motor pulley  38   a,  the timing belt  43 , and the registration large-diameter pulley  52  that are included in the sheet conveying device illustrated in  FIG. 4 ; the registration small-diameter pulley  55 ; the timing belt  44 ; the transmission shaft  62 ; the transmission shaft pulley  63 ; and the clutch gear  45 , the gear  51 , and the gear  67  that are forming a gear array. 
     On one end of the registration large-diameter pulley  52  of the registration roller  34 , the registration small-diameter pulley  55  is coaxially disposed. The transmission shaft  62  is rotatably supported by inner side plates  46   a  and  46   b.  The transmission shaft pulley  63  is secured to one end of the transmission shaft  62 . The timing belt  44  is wound around the registration small-diameter pulley  55  and the transmission shaft pulley  63 . Thus, the registration roller  34  and the transmission shaft  62  rotate in the same direction. 
     The clutch gear  45  is disposed on the transmission shaft  62  via the electromagnetic clutch  42 . When the electromagnetic clutch  42  is connected, a drive force of the drive motor  38  is transmitted to the transmission shaft  62 . When the electromagnetic clutch  42  is disconnected, the switching member  40  is held at the striking position or the evacuation position owing to a rotational load from a slip rotator, to be described in detail later. 
     The gear  51  is engaged with the gear  67 . The gear  51  is rotatably supported by a shaft  51   a  inserted into the gear  51 , The shaft  51   a  is secured to the inner side plate  46   a . The spring  66  is disposed between the inner side plate  46   a  and the disc member  91 . The disc member  91  is disposed between the spring  66  and the gear  51 . The gear  51  is loaded with a pressure from the spring  66 . Thus, even when the electromagnetic clutch  42  is disconnected, the switching member  40  can keep its position. 
     The shaft  41  of the switching member  40  is supported by the inner side plate  46   a  and another inner side plate disposed on a left side in  FIG. 9A  so as to be rotatable within a predetermined angular range. The shaft  41  of the switching member  40  is rotatably inserted into the gear  67  that is engaged with the clutch gear  45 . Thus, the gear  67  is rotatable relative to the shaft  41 . The disc member  87  is disposed between the gear  67  and the inner side plate  46   a,  to generate a frictional force with the spring  60 . The shaft  41  is rotatably inserted into the spring  60  and the disc member  87 . 
     The disc member  87  has a convex engagement part that is engaged with a groove formed on the shaft  41  in a longitudinal direction. The disc member  87  is slidable in a longitudinal direction of the shaft  41  and rotatable along with rotation the shaft  41  in the same direction. This configuration makes it possible to transmit a rotational drive force and torque of the gear  67  to the shaft  41 . 
     The gear  67 , the spring  60 , and the disc member  87  form a slip rotator. The slip rotator automatically blocks transmission of torque to the shaft  41  when an excessively large load is applied to the gear  67 , by making the gear  67  slip relative to the shaft  41 . 
     Referring to  FIG. 9A , the clutch gear  45 , the gear  51 , and the gear  67  are restricted in axial movement, by mounting retaining rings on each shaft rotatably supporting each gear. 
     As the electromagnetic clutch  42  is connected and the registration roller  34  is rotary-driven, a drove force is transmitted through the timing belt  44 , the clutch gear  45 , and the gear  67  to rotate the shaft  41  and to switch the position of the switching member  40 . At this time, the gear  51  is also rotated. The drive force transmitter makes the registration roller  34  and the shaft  41  rotate in the opposite directions. 
     Referring to  FIG. 9A , the filler  64  is secured to a right end of the shaft  41  into which the gear  67  is inserted. The filler  64  is in the form of a cup having a cutout used for detecting the rotational position of each switching member  40 . The position detection sensor  65  for detecting the cutout position of the filler  64  is disposed gripping the outer periphery of the filler  64 . The position detection sensor  65  includes a transmissive photosensor. The position detection sensor  65  detects the rotational position (e.g., striking position, switching position, evacuation position) of the switching member  40 . The position detection sensor  65  is secured to a sensor bracket  68  secured to the inner side plate  46   a.    
     In the slip rotator, the gear  67  is loaded by the disc member  87  and the spring  60  relative to the filler  64 . As a torque above a certain value acts on the gear  67 , a slip is caused between the disc member  87  and the filler  64 . Thus, the peripheral components never get broken even when the registration roller  34  is excessively rotated. Since the number of rotations of the registration roller  34  is accurately measurable by the encoder sensor  36 , the rotational position (rotational angle) of the switching member  40  is controllable. 
     The screw pins  89  and  90 , serving as second rotation regulators, are each secured to the inner side plate  46   a  with a screw so as to protrude toward the conveyer  32  side in a direction perpendicular to the inner side plate  46   a.  (The screw pin  90  is illustrated in  FIGS. 9B and 9C  while being omitted in  FIG. 9A .) 
     The spring pin  88 , serving as a first rotation regulator, is secured to the shaft  41  at right angle. The spring pin  88  is extended in the space between the screw pins  89  and  90 . As the registration roller  34  normally rotates in a direction indicated by arrow NR (corresponding to the ejection direction Xa) in  FIG. 10  and the shaft  41  rotates in a direction indicated by arrow A in  FIG. 9B , the spring pin  88  is brought into contact with the screw pin  90 , thereby restricting rotation of the shaft  41 . At this time, the switching member  40  is held in the striking position. 
     On the other hand, as the registration roller  34  reversely rotates in a direction indicated by arrow RR in  FIG. 10  and the shaft  41  rotates in a direction indicated by arrow B in  FIG. 9C  when the switching member  40  is in the striking position, the spring pin  88  is brought into contact with the screw pin  89 , thereby restricting rotation of the shaft  41 . At this time, the switching member  40  is held in the evacuation position. 
     As a drive force is transmitted to the gear  67  after the spring pin  88  has been brought into contact with the screw pins  89  or  90 , an excessively large load is applied to the gear  67  and a slip is caused between the disc member  87  and the filler  64 , thereby blocking transmission of torque to the shaft  41 . 
     As described above, the rotational position (e.g., striking position, switching position, evacuation position) of the switching member  40  can be detected by the position detection sensor  65  by detecting the rotational position of the filler  64  secured to the shaft  41 . 
     A configuration of the controller  110  of the image forming apparatus  1  is described below with reference to  FIG. 11 .  FIG. 11  is a block diagram of the configuration of the controller  110  in the image forming apparatus  1  illustrated in  FIG. 1 . 
     The controller  110  illustrated in  FIG. 11  controls major parts of the image forming apparatus  1 , including a part of the image former  2 , the feeder  3 , the ejector  4 , the sheet conveying device, the conveyer  32 , and the driver  33 . Referring to  FIG. 11 , the controller  110  includes a microcomputer including a central processing unit (CPU)  111  having functions of calculation and control, a read only memory (ROM)  112 , a random access memory (RAM)  113 , and a timer  114 . 
     The RAM  113  temporarily stores various data, such as calculation results of the CPU  111 . The ROM  12  previously stores necessary control programs (to be described later referring to  FIG. 13 ) and fixed data. 
     To the CPU  111 , each of the front cover open sensor  13 , the encoder sensor  29 , the sheet end detection sensor  30 , the encoder sensor  36 , the manual sensor  47 , the pre-registration sensor  49 , and the position detection sensor  65  is electrically connected via an input port. In addition, to the CPU  111 , a head driving circuit  71  for driving the liquid recording head  15 , the drive motor  21 , the drive motor  38 , and the electromagnetic clutch  42  is electrically connected via an output port. Further, an operation display  70  is electrically connected to the CPU  111  via an input port and an output port. 
     A set position detector, for detecting whether or not a trailing edge of a manually-inserted cut sheet is set at a proper set position relative to the image former  2 , is described below. The set position detector includes the sheet end detection sensor  30  as a major component and the encoder sensors  29  and  36  as sub components. 
     In the state illustrated in  FIG. 7 or 13  (to be described later), the set position detector provides the function of detecting (1) skew, (2) the size of the cut sheet, and (3) the right end of the cut sheet. In a case in which at least one of these three items does not meet each criterion, it is determined that the set position is wrong. 
     (1) Detection of Skew 
     The sheet end detection sensor  30  mounted on the carriage  20  detects the right end of the cut sheet  50  (or the sheet  10 ) while the carriage  20  is scanning in the main scanning direction Y (“first detection”). After tile cut sheet  50  (or the sheet  10 ) is conveyed in the ejection direction Xa for a predetermined amount, the sheet end detection sensor  30  detects the right end of the cut sheet  50  (or the sheet  10 ) again (“second detection”). The difference in detected position between the first and second detections represents a skew. When the skew is in excess of a specified value, the set position is determined to be wrong. 
     (2) Detection of Size of Cut Sheet 
     The sheet end detection sensor  30  detects the right end of the cut sheet  50  (or the sheet  10 ) while the carriage  20  is scanning in the main scanning direction Y. The carriage  20  keeps on scanning to detect the left end of the cut sheet  50  (or the sheet  10 ). The difference in detected position between the right and left ends represents the width (size) of the sheet. When the detected size of the cut sheet  50  (or the sheet  10 ) is out of a specified range, the set position is determined to be wrong. 
     (3) Detection of Right End of Sheet 
     The sheet end detection sensor  30  detects the right end of the cut sheet  50  (or the sheet  10 ) while the carriage  20  is scanning in the main scanning direction Y. When the detected value is out of a specified range, the set position is determined to be wrong. 
     The operation display  70  includes: a touch panel, switches, and keys, for instructing each part of the image forming apparatus  1  to perform each operation; a liquid crystal display for visually checking the operation; and a sound generator. The liquid crystal display and the sound generator each serve as an informer. Examples of the sound generator include a voice generator and a buzzer that generates a warning sound. 
     In the first embodiment, the CPU  111  serves as a first controller. Specifically, the CPU  111  serving as the first controller controls the drive motor  38  and the electromagnetic clutch  42  such that the registration roller  34  normally rotates to convey the cut sheet  50  from the manual conveyance path  11  to the ejector  4  and that the switching member  40  swings from the evacuation position to the striking position, based on a signal indicating that the set potion of the cut sheet  50  is wrong, transmitted from the set position detector (including the sheet end detection sensor  30 ). 
     In addition, the CPU  111  has an interlock function that stops operations of the head driving circuit  71  of the liquid recording head  15 , the drive motor  21 , the drive motor  38 , and the electromagnetic clutch  42 , based on a signal indicating that the cover is open, transmitted from the front cover open sensor  13 . 
     Moreover, the CPU  111  has a function that causes the liquid crystal display and the sound generator in the operation display  70  inform the user of the status of each part, such as the electromagnetic clutch  42 , drive motors  21  and  38 , etc., based on a signal from each sensor. 
     Now, a manual feeding preparation operation for a manually-inserted cut sheet (simply referred to as “sheet” in  FIG. 13 ), performed by the image forming apparatus  1  under control of the controller  110  is described with reference to  FIG. 13 . For the illustrative purposes, however, user operation performed at S 21  to S 25  (blocks drawn by thick lines) are described, together with operation performed by the controller  110  in response to such user operation. 
     In step S 21  in  FIG. 13 , as the user opens the front cover  12  as illustrated in  FIG. 2 , the controller  110  receives a detection result indicating the open state of the front cover  12  from the front cover open sensor  13 . In step S 22 , as the user operates the pressure releasing lever  54  in the direction indicated by arrow in  FIG. 2 , the pressure rollers  35  are separated upward from the registration roller  34  to be held in the depressurizing position. In step S 23 , the user inserts the cut sheet  50  from the ejection port  4   a  (illustrated in  FIG. 2 ) until the leading edge  50   a  of the cut sheet  50  strikes against the switching member  40  held in the striking position, as illustrated in  FIG. 6 . 
     Whether or not the leading edge  50   a  of the cut sheet  50  has struck against the switching member  40  is detected by the manual sensor  47 . In step S 24 , the user operates the pressure releasing lever  54  in the direction indicated by arrow in  FIG. 1 , so that the pressure rollers  35  are pressed against the registration roller  34  to be held in the pressurizing position. In step S 25 , the user closes the front cover  12 . The controller  110  receives a detection result indicating the close state of the front cover  12  from the front cover open sensor  13 . 
     In step S 26 , the cut sheet  50  having struck against the switching member  40  is then automatically conveyed in the conveyance direction Xc, as illustrated in  FIG. 7 , as the electromagnetic clutch  42  (illustrated in  FIG. 9A ) is connected and the registration roller  34  is reversely rotated. At the same time in step S 26 , the switching member  40  swings to the evacuation position so as not to interrupt conveyance of the cut sheet  50 . 
     As the trailing edge  50   b  of the cut sheet  50  reaches an immediately upstream position of the print start position in the conveyance direction Xc, the set position of the trailing edge  50   b  of the cut sheet  50  is detected by the set position detector (including the sheet end detection sensor  30 ) mounted on the carriage  20 . 
     The set position detector then performs detection of (1) skew, (2) the size of the cut sheet, and (3) the right end of the cut sheet. In step S 27 , the CPU  111  refers to fixed data or a data table stored in the ROM  112  to determine whether the set position is good or wrong. 
     When the set position is determined to be good, in step S 28 , the trailing edge  50   b  of the cut sheet  50  is conveyed to a writing position where the liquid recording heads  15  are capable of writing an image on the cut sheet  50 , by the registration roller  34  normally rotated and the pressure rollers  35 , as illustrated in  FIG. 8 . 
     In this operation according to the first embodiment, the above-described steps S 21  to S 28  are the same as steps S 1  to S 8 , respectively, in a related-art operation illustrated in  FIG. 12 . When the set position is determined to be wrong in step S 27 , the following operation is automatically performed, which is different from the related-art operation illustrated in  FIG. 12  to be described later. 
     In step S 29 , the CPU  111  serving as the first controller automatically performs an operation that causes the cut sheet to be automatically ejected and causes the switching member  40  to automatically transfer to the striking position. Specifically, the CPU  111  controls the drive motor  38  and the electromagnetic clutch  42  such that the registration roller  34  normally rotates to convey the cut sheet  50  from the manual conveyance path  11  to the ejector  4  and that the switching member  40  swings from the evacuation position to the striking position. 
     In step S 30 , information indicating completion of ejection of the cut sheet is displayed on the liquid crystal display of the operation display  70 . Thus, the user recognizes that a sheet re-setting operation is needed and performs the sheet re-setting operation (i.e., step S 21  and subsequent steps). 
     Now for the comparative purposes, the related-art manual feeding preparation operation for a manually-inserted cut sheet (simply referred to as “sheet” in  FIG. 12 ) is described with reference to  FIG. 12 . In  FIG. 12 , blocks drawn by thick lines represent manual operations performed by a user. Further, for simplicity, it is assumed that hardware of the related-art image forming apparatus is substantially the same as that of the image forming apparatus  1 , except for a controller that controls hardware of the image forming apparatus. For this reasons, the same reference numerals are used to explain the hardware component. 
     As described below, the image for apparatus according to the related art only controls the drive motor  38  and the electromagnetic clutch  42  such that the switching member  40  is switched from the striking position to the evacuation position when the registration roller  34  is reversely rotated and the trailing edge of the cut sheet  50  occupies the set position. In addition, the image forming apparatus according to the related art causes the liquid crystal display and the sound generator in the operation display  70  inform the user, only based on a signal indicating that the set potion of the cut sheet  50  is wrong, transmitted from the set position detector (including the sheet end detection sensor  30 ). 
     Referring back to  FIG. 12 , when the set position is determined to be wrong, in step S 9 , a CPU displays a warning about wrong set position on the liquid crystal display of the operation display  70  or generates a warning sound. Operations to be performed by the user and the operation order may be also displayed on the liquid crystal display. Thus, the user can recognize that the set position is wrong and a sheet re-setting operation is needed in step S 9 . The user then opens the front cover in step S 10 , and operates the pressure releasing lever  54  to a depressurizing state in step S 11 . 
     In step S 12 , the user removes the cut sheet, determined to be in a wrong set position, from the positions of the pressure rollers  35  separated from the registration roller  34 . The user then operates the pressure releasing lever  54  to a pressurizing state in step S 13  in the same manner as in step S 4 , and closes the front cover in step S 14  in the same manner as in step S 5 . 
     In step S 15 , an initial operation; including a carriage forming operation and a switching operation for transferring the switching member  40  to the striking position, is automatically performed. Since the front cover  12  was opened in the prior step, the carriage needs to check whether or not foreign substances present on the print surface by slowly scanning the whole area in the main scanning direction. Such a scanning operation causes a waste of time. To omit the time spent for the scanning operation, the initial operation is automatically performed in step S 15 . 
     As the switching member  40  has switched to the striking position through steps S 10  to S 15 , the cut sheet gets ready for being reset. The user then performs a series of steps S 1  to S 5  to reset the cut sheet. 
     In the related-art image forming apparatus, as described above, the switching member  40  is not in the striking position when reset of the cut sheet is required, and therefore a series of complicated operations is needed. Specifically, the series of complicated operations includes manual operations (e.g., opening the front cover, operating the pressure releasing lever to the depressurizing state, removing the cut sheet, operating the pressure releasing lever to the pressurizing state, closing the front cover) and the initial operation (e.g., the carriage forming operation and the switching operation for switching the switching member  40  to the striking position). The series of complicated operation takes a long time. 
     Further, when the front cover is opened, the CPU stops an operation of the drive motor  38 , etc., based on a signal indicating that the cover is open, transmitted from the front cover open sensor  13 . By this interlock function of the CPU, the drive motor  38  cannot be put into operation. 
     In contrary, according to the first embodiment of the present invention, when the set position is determined to be wrong, the cut sheet can be properly reset without complicated operation, because the cut sheet is ejected without being touched by the user and the switching member  40  is automatically transferred to the striking position at the same time. 
     Since no complicated operation is required, a waste of time can be minimized. 
     Modification 1 
     A first modification is described below with reference to  FIGS. 14A and 14B .  FIGS. 14A and 14B  are side views of an image forming apparatus according to the first modification, in a cut sheet ejection operation. 
     The first modification is different from the first embodiment in the following two aspects. With respect to the first aspect, step S 29  in the first embodiment is modified such that conveyance of the manually-inserted cut sheet  50  to the ejector  4  is completed while the cut sheet  50  is being sandwiched by the registration roller  34  and the pressure rollers  35 , as illustrated in  FIG. 14B . 
     With respect to the second aspect, the CPU  111  serves as a second controller in addition to serving as the first controller. The CPU  111  serving as the second controller controls the electromagnetic clutch  42  and the drive motor  38  such that the electromagnetic clutch  42  gets connected and the switching member  40  swings to the striking position at the time when the manual sensor  47  detects absence of the manually-inserted cut sheet  50 , to transfer the switching member  40  to the striking position while the manually-inserted cut sheet  50  is being ejected. 
     According to the first aspect, when the set position is determined to be wrong, the cut sheet  50  is conveyed toward the ejector  4  (while the switching member  40  is in the striking position), and the conveyance is stopped while the cut sheet  50  is being sandwiched by the registration roller  34  and the pressure rollers  35 , as illustrated in  FIG. 14B . 
     A stop position of the trailing edge of the cut sheet  50  (corresponding to the leading edge  50   a  of the manually-inserted cut sheet  50 ) is between a position within the manual conveyance path  11  (formed of the manual sheet conveyance guide plates  251  and  252 ) and the nip position of the registration roller  34 . 
     The amount of conveyance of the cut sheet  50  is controllable by the accumulated normal/reverse rotation pulse number of the registration roller  34 , detected by the encoder sensor  36 , which may be a constant value regardless of the length of the cut sheet  50 . 
     Thus, the cut sheet  50  is prevented from falling and being soiled or bent. 
     According to the second aspect, when the set position is determined to be wrong, the cut sheet  50  is conveyed toward the ejector  4  in the ejection direction Xa, as illustrated in  FIG. 14A . To transfer the switching member  40  to the striking position while the manually-inserted cut sheet  50  is being ejected, the electromagnetic clutch  42  gets connected and the switching member  40  swings to the striking position at the time when the manual sensor  47  detects absence of the manually-inserted cut sheet  50 . Thus, the cut sheet  50  and the switching member  40  are controllable without being touched by the user. 
     Modification 2 
     A second modification is described below with reference to  FIG. 15 .  FIG. 15  is a flowchart of a manual feeding preparation operation for an image forming apparatus according to the second modification. 
     The second modification is different from the first modification in that the CPU  111  serves as a third controller in addition to serving as the second controller. The CPU  111  serving as the third controller controls the sound generator in the operation display  70  to inform that the manually-inserted cut sheet  50  is set at the set position based on a signal indicating that the manually-inserted cut sheet  50  has struck against the switching member  40  in the striking position, transmitted from the manual sensor  47 . 
     The operation according to the second modification illustrated in  FIG. 15  is different from that according to the first embodiment and the first modification illustrated in  FIG. 13  in that a sheet set alarm is sounded in step S 35  when the manual sensor  47  detects presence of the cut sheet in step S 34  and that reset of the cut sheet is informed in step S 41 . 
     In other words, when the leading edge  50   a  of the cut sheet  50  is properly set within the manual conveyance path  11  by striking against the switching member  40  in the striking position, a sheet set alarm is sounded as the manual sensor  47  detects presence of the cut sheet. 
     In a case in which the cut sheet  50  is manually inserted as illustrated in  FIG. 6 , the cut sheet  50  may enter into the conveyance path  5  exclusively used for the rolled sheet, without entering into the manual conveyance path  11 , depending on the degree of curl of the leading edge  50   a  of the cut sheet  50 . 
     To avoid such a phenomenon, the image forming apparatus according to the second modification can inform the user of proper set of the cut sheet by means of a sheet set alarm, etc., optionally together with a display. When the cut sheet has not properly set, the image forming apparatus informs the user of wrong set of the cut sheet to prompt the user to reset the cut sheet. Wrong set of the cut sheet may be displayed on the liquid crystal display of the operation display  70  and/or alarmed by a buzzer sound, to reliably prompt the user to reset the cut sheet. 
     Modification 3 
     A third modification is described below with reference to  FIGS. 16A to 16C .  FIGS. 16A to 16C  are side views of an image forming apparatus according to the third modification. 
     The third modification is different from the first embodiment in the following two aspects. Firstly, the installation position of the switching member  40  is changed to an upstream side of the joined conveyance path  14  relative to the insertion direction Xb. Secondly, the switching member  40  is made switchable among the striking position illustrated in  FIG. 16A , the evacuation position illustrated in  FIG. 16C , and a separation position illustrated in  FIG. 16B . The switching member  40  in the separation position allows the cut sheet  50  only to enter into the manual conveyance path  11 . 
     The third modification may be applied to the second modification. In the third modification, to make the switching member  40  swingable among the striking position, evacuation position, and separation position, the driver  33  (illustrated in  FIGS. 9A ) may be modified or the drive motor  38  is replaced with another drive motor. 
     In the first embodiment, when the cut sheet  50  is manually inserted and set, the cut sheet  50  may enter into or strike against the conveyance path  5 , exclusively used for the rolled sheet without entering into the manual conveyance path  11 , depending on the degree of curl of the leading edge  50   a  of the cut sheet  50 . The third modification has solved such a problem. 
     The image forming apparatus according to some embodiments of the present inventions is not limited to an inkjet recording apparatus. The image forming apparatus according to some embodiments of the present invention may be an electrophotographic copier or printer which forms images on either a long sheet drawn from a sheet roll or a cut sheet manually inserted. Specific examples of the long sheet include, but are not limited to, various recording media such as normal sheet, recording sheet, gloss sheet, and coated sheet. Specific examples of the cut sheet used for manual insertion include, but are not limited to, various recording media such as normal sheet, recording sheet, gloss sheet, coated sheet, thick sheet, envelope, thin sheet, and film (e.g., OHP sheet), and a cut piece of the long sheet. The long sheet and the cut sheet may be made of paper, fiber, or plastic. 
     The liquid discharge head of the inkjet recording apparatus includes an energy generation source. Specific examples of the energy generation source include, but are not limited to, a piezoelectric actuator (e.g., a laminated piezoelectric element, a thin-film piezoelectric element), a thermal actuator using a thermoelectric conversion element such as a heat element, and an electrostatic actuator including a vibration plate and a counter electrode. 
     Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that, within the scope of the above teachings, the present disclosure may be practiced otherwise than as specifically described herein. With some embodiments having thus been described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the scope of the present disclosure and appended claims, and all such modifications are intended to be included within the scope of the present disclosure and appended claims.