Patent Publication Number: US-7222847-B2

Title: Feeding apparatus and recording apparatus having the same

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a feeding apparatus for feeding a recording medium such as a sheet material, a film material or a cut paper sheet one by one, and a recording apparatus equipped with such feeding apparatus. 
   2. Related Background Art 
   As a recording apparatus for recording a character or an image on a recording medium such as a cut paper sheet, there have conventionally been known an ink jet recording apparatus, a thermal transfer recording apparatus, an electrophotographic recording apparatus, etc. 
   Among these, a smaller configuration of the entire recording apparatus and a lower production cost are requested for the ink jet recording apparatus and the thermal transfer recording apparatus as they are often used in personal applications. 
     FIG. 21  is an external perspective view of a prior ink jet recording apparatus. In  FIG. 21 , a recording medium  200  is set in an automatic sheet feeding apparatus (hereinafter represented as ASF)  201 . The ASF  201  is provided with a cover  202  for a main body of a recording portion having an ink jet recording portion therein. The ASF  201  is provided with a discharge tray  203  for supporting a recording medium after recording. 
     FIG. 22  is a perspective view of the ASF only in  FIG. 21 , in the course of a feeding operation. 
   Referring to  FIG. 22 , The ASF  201  is provided with an ASF base  209  for setting the recording medium  200 . The ASF base  209  supports a feeding roller shaft  203 , on which provided is a feeding rubber  206 .  FIG. 23  is a cross-sectional view showing the feeding rubber  206 . As shown in  FIG. 23 , the feeding rubber  206  has a D-shaped cross section, and it is moved, prior to a feeding operation, to a position where a straight portion of the D-shape is opposed to the recording medium thereby preventing a friction between the recording medium and the feeding rubber  206 . The recording medium is set along a pressure plate  210 , which is brought closer to the feeding rubber  206  only in a feeding operation and is contacted with the recording medium  200  by a power of an unillustrated compression spring provided behind the pressure plate  210 . The feeding roller shaft  203  receives a driving power from an unillustrated motor through a gear train  207 , and is rotated in a direction to convey the recording medium  200  from the ASF base toward an unillustrated recording portion. A sensor masking portion  204 , integrally formed on the feeding roller shaft  203 , rotates together with the feeding roller shaft  203  and masks or exposes a transmission photosensor  205  fixed on an unillustrated substrate. The pressure plate  210  is contacted with and separated from the feeding roller  206 , in synchronization with one turn of the feeding roller shaft  203 . 
   A configuration executing such elevation and lowering of the pressure plate in synchronization with a rotating operation of the feeding roller shaft is disclosed for example in Japanese Registered Patent No. 3090161. 
   In an initial operation state of the ASF  201 , the feeding roller shaft  203  is in such a rotational position that the sensor masking portion  204  masks the transmission photosensor  205 . In such state the pressure plate  210  is separated from the feeding rubber  206 . In case it is in a non-masking position, an initializing operation is executed by an initialization signal from the main body of the ink jet recording apparatus. In case it is in a masking position, after the entry of a recording signal, the feeding roller shaft  203  starts rotation and the pressure plate  210  approaches the feeding rubber  206 , whereby the feeding rubber  206  comes into contact with the recording medium  200  thereby executing a feeding thereof. The recording medium  200  thus fed is separated into a sheet in a separating portion  208  and conveyed to the recording portion. 
   However, the prior recording apparatus described above has been associated with following drawbacks. 
   Firstly, in the prior recording apparatus, it is necessary to establish an initial position for the feeding operation, in order to prevent a frictional contact between the recording medium and the feeding roller rubber, and a position sensor is provided for this purpose. Therefore the prior recording apparatus requires a complex electrical structure with an increased production cost. Also since a drive control is executed for stopping a motor in response to a detection signal from the sensor, it is necessary to secure a precision in the stopping position of the motor. Therefore, a highly precise motor is required, leading to an increase in the production cost. 
   By forming the feeding roller rubber in a circular shape instead of the D-shape, it is no longer necessary to initialize the rotational position of the feeding roller rubber, but the position of the pressure plate needs to be initialized. In the prior configuration, a sensor is still required to initialize the pressure plate, thereby elevating the production cost as in the above-described configuration. 
   Secondly, in case the distance from the feeding roller rubber to the recording portion is made long, the feeding roller rubber is required to have a circumferential length at least equal to the feeding distance to the recording portion, so that it has to have a large diameter, thus increasing the dimension of the entire recording apparatus. 
   Particularly in an ASF of so-called cassette feeding type in which the recording media are set horizontally, instead of the above-described ASF which is provided in the conventional recording apparatus and in which the recording media are placed on a pressure plate in a state inclined from the horizontal direction, the diameter of the feeding roller directly influences the height of the entire recording apparatus. Therefore, such ASF is difficult to employ in realizing a recording apparatus of a reduced height, thus resulting in a large installation space. 
   Also, together with an increase in the size of the entire recording apparatus, an external casing, such as a cover, for the entire apparatus also becomes larger, thus resulting in an increase in the cost of the material for forming the external casing etc. and elevating the production cost. 
   Particularly in case of employing a feeding roller rubber of a D-shaped cross section for preventing frictional contact between the recording medium and the feeding roller rubber as in the prior recording apparatus described above, the circumferential length of the arched portion of the feeding roller rubber, other than the straight portion thereof, has to be made longer than the feeding distance to the recording portion. Therefore, an even larger diameter is required than in the feeding roller rubber of the circular shape, thus being difficult to use in realizing a recording apparatus of a reduced height. 
   Thirdly, the prior recording apparatus utilizes the biasing force of a compression coil spring provided at the rear side of the pressure plate, as pressurizing means for pressing the pressure plate to the feeding roller rubber. For this reason, a medium stacking portion for stacking the recording media becomes thicker by the length of such compression coil spring, thereby leading to an increase in the dimension of the entire apparatus. This drawback becomes more conspicuous, as in the case of the roller diameter mentioned above, in so-called cassette feeding in which the recording media are stacked horizontally. 
   SUMMARY OF THE INVENTION 
   In consideration of the foregoing, an object of the present invention is to provide a feeding apparatus, capable of reducing the dimension of the entire apparatus and the production cost thereof, and a recording apparatus utilizing the same. 
   The aforementioned object can be attained, according to the present invention, by a feeding apparatus including a feeding roller for feeding a recording medium, a pressure plate provided movably between a contact position pressed to the feeding roller and a separated position separated from the feeding roller, pressure plate pressing means which provides the pressure plate with a pressing load for contacting the pressure plate with the feeding roller, and a motor for generating a driving power for moving the pressure plate to the contact position and to the separated position and a driving power for rotating the feeding roller. The feeding apparatus of the present invention also includes first drive transmission means which rotates the motor in a forward direction to contact and separate the pressure plate with and from the feeding roller, then shifts the driving power to the pressure plate to a non-transmission state, rotates the motor in a reverse direction to again transmit the driving power to the pressure plate thereby returning the pressure plate to an initial separated state prior to the rotation in the forward direction and shifts the driving power to the pressure plate to a non-transmission state, and second drive transmission means which transmits the driving power from the motor to the feeding roller. Further, the feeding apparatus of the present invention includes medium separation means which is provided in a downstream side of a contact position between the pressure plate and the feeding roller in a conveying direction of the recording medium and which separates the recording media one by one, conveying means which is provided in a downstream side of the medium separation means, for conveying the recording medium, and control means which includes detection means for detecting arrival of a leading end of the recording medium at the conveying means and which reverses the motor after the detection of the leading end of the recording medium by the detection means. 
   The feeding apparatus of the present invention having the aforementioned configuration allows to dispense with phase detection means for detecting a rotational phase of the feeding roller and is capable of securely controlling the drive of the feeding roller. 
   Also the second drive transmission means provided in the feeding apparatus of the present invention transmits a driving power from the motor to the feeding roller through the first drive transmission means, and the feeding roller is rotated and stopped in synchronization with a transmission state and a non-transmission state of the driving power to the pressure plate. The feeding roller can therefore be rotated only during a period necessary for feeding. Consequently it is possible to securely control the rotational phase of the feeding roller without employing phase detection means, even in case the feeding roller has a non-circular cross-sectional shape, such as a D-shape. 
   The feeding apparatus of the present invention further includes a transfer roller positioned at a downstream side of the medium separation means and at an upstream side of the conveying means and serving to convey the recording medium, a pinch roller pressed to the transfer roller, and third drive transmission means for transmitting a rotary driving power from the motor to the transfer roller. The recording medium, fed by the feeding roller, can thus be transferred to the conveying means by means of the transfer roller and the pinch roller. 
   The third drive transmission means provided in the feeding apparatus of the present invention rotates the transfer roller in a direction for transferring the recording medium toward the conveying means, regardless whether the motor is rotated in the forward direction or in the reverse direction. Thus, even when the motor is reversed for transmitting the driving power so as to return the pressure plate to the separated position (initial position), the transfer roller does not rotate in the reverse direction but advances the recording medium in the feeding direction. 
   Also the third drive transmission means provided in the feeding apparatus of the present invention transmits the driving power from the motor to the transfer roller in a forward rotation state of the motor, and attains a non-transmission state of interrupting the transmission of the driving power in a reverse rotation state of the motor. In this manner, the transfer roller can be rotated by the conveying means when the motor is rotated in the reverse direction. 
   The feeding apparatus of the present invention further includes contact/separation means which contacts the transfer roller and the pinch roller when the motor is rotated in the forward direction and separates the transfer roller and the pinch roller when the motor is rotated in the reverse direction. Thus, the transfer roller and the recording medium can be maintained in a non-contact state after the leading end of the recording medium reaches the conveying means. 
   Also the pressure plate pressing means provided in the feeding apparatus of the present invention includes a spring for generating a contact load, and direction converting means which changes a direction of load substantially perpendicularly from a biasing direction of the spring to contact direction of the pressure plate to the feeding roller. Therefore, a length of the spring, in a direction of elastic deformation thereof, requires a smaller space in the stacking direction of the recording media (a direction perpendicular to the principal plane of the recording medium), thereby allowing to reduce the dimension of the feeding apparatus in the direction parallel to the stacking direction of the recording media and to reduce the dimension of the recording apparatus. 
   Also the pressure plate pressing means provided in the feeding apparatus of the present invention includes a first movable plate for moving the pressure plate, and a second movable plate for moving the first movable plate. The first and second movable plates are positioned parallel to the pressure plate when it is moved to the separated position. Therefore, the first and second movable plates for moving the pressure plate require a smaller space in the stacking direction of the recording media, thereby allowing to reduce the dimension of the feeding apparatus in the direction parallel to the stacking direction of the recording media and to reduce the dimension of the recording apparatus. 
   Further, the recording apparatus of the present invention includes recording means which executes a recording on the recording medium fed by the feeding apparatus of the present invention. 
   As explained in the foregoing, the feeding apparatus of the present invention includes a feeding roller for feeding a recording medium, a pressure plate provided movably between a contact position pressed to the feeding roller and a separated position separated from the feeding roller, pressure plate pressing means which provides the pressure plate with a pressing load for contacting the pressure plate with the feeding roller, a motor for generating a driving power for moving the pressure plate to the contact position and to the separated position and a driving power for rotating the feeding roller, first drive transmission means which rotates the motor in a forward direction to contact and separate the pressure plate with and from the feeding roller, then shifts the driving power to the pressure plate to a non-transmission state, rotates the motor in a reverse direction to again transmit the driving power to the pressure plate thereby returning the pressure plate to an initial separated state prior to the rotation in the forward direction and shifts the driving power to the pressure plate to a non-transmission state, second drive transmission means which transmits the driving power from the motor to the feeding roller, medium separation means which is provided in a downstream side of a contact position between the pressure plate and the feeding roller in a conveying direction of the recording medium and which separates the recording media one by one, conveying means which is provided in a downstream side of the medium separation means, for conveying the recording medium, and control means which includes detection means for detecting arrival of a leading end of the recording medium at the conveying means and which reverses the motor after the detection of the leading end of the recording medium by the detection means, and can thus dispense with a position sensor required for detecting an initial position of the pressure roller and a high-precision motor and can achieve an automatic initialization of the pressure plate by merely repeating the forward and reverse drives of the motor, to enable a next feeding operation, thereby realizing a reduction in the production cost. 
   Also the second drive transmission means provided in the feeding apparatus of the present invention transmits a driving power from the motor to the feeding roller through the first drive transmission means, and rotates and stops the feeding roller in synchronization with a transmission state and a non-transmission state of the driving power to the pressure plate, thereby rotating the feeding roller only during a period necessary for feeding. Therefore the feeding apparatus of the present invention can dispense with a position sensor for detecting the initial position of the pressure plate and the feeding roller and a high-precision motor and can achieve an automatic initialization of the pressure plate and the feeding roller by merely repeating the forward and reverse drives of the motor, to enable a next feeding operation, thereby realizing a reduction in the production cost. 
   The feeding apparatus of the present invention also includes a transfer roller positioned at a downstream side of the medium separation means and at an upstream side of the conveying means and serving to convey the recording medium, a pinch roller pressed to the transfer roller, and third drive transmission means for transmitting a rotary driving power from the motor to the transfer roller, and can thus set a feeding amount by the feeding roller at a feeding distance for the recording medium to reach the transfer roller, thereby allowing to reduce the diameter of the feeding roller and realizing reductions in the dimension and the production cost of the feeding apparatus. 
   The third drive transmission means provided in the feeding apparatus of the present invention rotates the transfer roller in a direction for transferring the recording medium toward the conveying means, regardless whether the motor is rotated in the forward direction or in the reverse direction, whereby, even when the motor is reversed for transmitting the driving power so as to return the pressure plate to the separated position, the transfer roller does not rotate in the reverse direction but advances the recording medium in the feeding direction. Therefore, in the reverse rotation state of the transfer roller, the recording medium is prevented from being pulled to the upstream side and being rubbed, whereby a recording apparatus of an excellent recording quality can be realized without a fluctuation in a recording start position or a damage of the recording medium. 
   Also the third drive transmission means provided in the feeding apparatus of the present invention transmits the driving power from the motor to the transfer roller in a forward rotation state of the motor, and attains a non-transmission state of interrupting the transmission of the driving power in a reverse rotation state of the motor, thereby rotating the transfer roller by the conveying operation of the conveying means when the motor is rotated in the reverse direction, whereby a recording apparatus of an excellent recording quality can be realized without a fluctuation in a recording start position or a damage of the recording medium. 
   The feeding apparatus of the present invention further includes contact/separation means which contacts the transfer roller and the pinch roller when the motor is rotated in the forward direction and separates the transfer roller and the pinch roller when the motor is rotated in the reverse direction, thereby maintaining the transfer roller and the recording medium in a non-contact state after the leading end of the recording medium reaches the conveying means, and preventing the conveying means from a load in an intermittent conveying the conveying means. Thus a recording apparatus of an excellent recording quality can be realized without white streaks or black streaks generated by a low feeding precision. 
   Also the pressure plate pressing means provided in the feeding apparatus of the present invention includes a spring for generating a contact load, and direction converting means which changes a direction of load substantially perpendicularly from a biasing direction of the spring to a contact direction of the pressure plate to the feeding roller, thereby allowing to reduce the dimension of the feeding apparatus in the direction parallel to the stacking direction of the recording media and to reduce the dimension of the recording apparatus. 
   Also the pressure plate pressing means provided in the feeding apparatus of the present invention includes a first movable plate for moving the pressure plate, and a second movable plate for moving the first movable plate. The first and second movable plates are positioned parallel to the pressure plate when it is moved to the separated position, thereby allowing to reduce the dimension of the feeding apparatus in the direction parallel to the stacking direction of the recording media and to reduce the dimension of the recording apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view showing a recording apparatus in a first embodiment of the present invention; 
       FIG. 2  is a perspective view showing a cassette feeding unit; 
       FIG. 3  is a perspective view showing a feeding cassette; 
       FIG. 4  is a perspective view showing a main body of the unit; 
       FIG. 5  is a cross-sectional view showing an initial state of a feeding roller rubber, sectioned at a center in an axial direction thereof; 
       FIG. 6  is a cross-sectional view showing a state under feeding of a feeding roller rubber, sectioned at a center in an axial direction thereof; 
       FIG. 7  is a perspective view showing first and second pressure plate pressing plates in a state shown in  FIG. 6 ; 
       FIG. 8  is a lateral view seen from outside of a right-side chassis; 
       FIG. 9  is a schematic view showing a vicinity of a first pendulum gear unit seen from inside of the right-side chassis; 
       FIG. 10  is a schematic view showing a vicinity of a second pendulum gear unit seen from inside of the right-side chassis; 
       FIG. 11  is a perspective view showing an inside of the right-side chassis; 
       FIG. 12  is a perspective view showing a pressure plate pendulum gear unit seen from a rear side; 
       FIG. 13  is a perspective view showing a state when a pressure plate cam gear is rotated from a state shown in  FIG. 11 ; 
       FIG. 14  is a perspective view showing a state when the pressure plate cam gear is rotated by 320° from a state shown in  FIG. 11 ; 
       FIG. 15  is a perspective view showing a supporting structure of a wire pulley; 
       FIG. 16  is a perspective view showing a vicinity of a left-side chassis; 
       FIG. 17  is a cross-sectional view sectioned along X in  FIG. 1 ; 
       FIG. 18  is a control circuit diagram of a recording apparatus; 
       FIG. 19  is a flow chart showing a recording operation in the recording apparatus; 
       FIG. 20  is a perspective view showing a vicinity of a transfer roller in a second embodiment; 
       FIG. 21  is an external perspective view showing a prior ink jet recording apparatus; 
       FIG. 22  is a perspective view showing a prior ASF; and 
       FIG. 23  is a cross-sectional view showing a prior feeding rubber portion. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the following, the present invention will be explained by specific embodiments thereof, with reference to the accompanying drawings. 
   First Embodiment 
     FIG. 1  is a perspective view showing a first embodiment of the present invention. As shown in  FIG. 1 , a recording apparatus of the present embodiment is provided with a cassette feeding unit  1  for feeding a recording medium, and a main body  100  of the recording apparatus for recording a character, an image etc. on the recording medium fed by the cassette feeding unit  1 . 
   The cassette feeding unit  1 , when the main body  100  of the recording apparatus is mounted by positioning thereon as shown in  FIGS. 1 and 2 , can feed the recording medium to the main body  100  for a recording therein. 
   As shown in  FIG. 2 , the cassette feeding unit  1  is provided with a unit main body portion  2  for feeding the recording medium, and a feeding cassette  3  provided detachably on the unit main body portion  2  and containing plural recording media. 
     FIG. 3  is a perspective view showing the entire feeding cassette  3 , which will be explained with reference to  FIG. 3 . 
   As shown in  FIG. 3 , the feeding cassette  3  has a cassette tray  4  for stacking plural recording media (not shown), capable of setting recording media of various sizes from a B5 size to an A4 size and a LTR (letter) size. Positioning of the recording medium is achieved by causing lateral ends of the recording medium to impinge respectively on reference lateral walls  10 ,  11  in the cassette tray  4 , and by moving a side guide  5  and an end guide  6  so as to respectively abut on the external periphery of the recording medium. Such side guide  5  and end guide  6  are fixed by a ratchet  7  to the cassette tray  4 . 
   On a bottom face of the cassette tray  4 , a pressure plate  8  is rotatably provided. The pressure plate  8  is rendered rotatable, about a rotary center provided at an end and formed by rotary supporting portions  8   a ,  8   b  on a same axis, between a contact position contacted with a feeding roller rubber  29  to be explained later and a separated position separated from the feeding roller rubber  29 . 
   On the pressure plate  8 , a separating sheet  9  is fixed for example with a both-side adhesive tape. The separating sheet  9  is formed for example by a cork material and provides a frictional force to a recording medium positioned closest to bottom side of the cassette tray  4 , thereby preventing so-called superposed feeding in which plural recording media are erroneously advanced. After plural recording media are stacked, the feeding cassette  3  is inserted and mounted in a main body portion  2  of the feeding unit to be explained later. 
   As shown in  FIG. 2 , the cassette feeding unit  1  has a right outer casing panel  13  and a left outer casing panel  14  and has an external shape matching that of the main body  100  of the recording apparatus to be explained later. The cassette feeding unit  1  also has a right-side cover  15 , a left-side cover  16  and a separation base  17 , which are so provided as to cover mechanical components to be explained later and are respectively provided with positioning surfaces for positioning the feeding cassette  3  relative to the unit main body portion  2 . Also in a position adjacent to the separation base  17 , there is provided an upper stay  18  formed by a metal plate and constituting a structural member for maintaining the mechanical strength of the entire cassette feeding unit  1 . The right-side cover  15  and the left-side cover  16  are respectively provided with hooks  19 ,  20  for engaging with the main body  100  of the recording apparatus, whereby the main body  100  mounted on the cassette feeding unit  1  is fixed thereto. 
   On the separation base  17 , there stand positioning pins  21 ,  22  by which the main body  100  of the recording apparatus is positioned relative to the cassette feeding unit  1 , when the main body  100  of the recording apparatus is placed and mounted thereon. Also on the separation base  17 , there are provided movable hooks  23 ,  24  which are biased in the illustrated positions by springs (not shown) and are rotated to engage with the main body  100  of the recording apparatus when it is placed. A rear button (not shown), when pressed in, rotates and unlocks the movable hooks  23 ,  24  against the elastic force of the springs, whereupon the main body  100  of the recording apparatus can be lifted and separated from the cassette feeding unit  1 . 
   The separation base  17  is provided with a female connector  47 , which engages and is connected with a male connector on a bottom face of the main body  100  of the recording apparatus when it is placed, whereby a power supply and a motor drive signal to be explained later are entered from the main body  100  of the recording apparatus to a circuit board (not shown). 
     FIG. 4  is a perspective view of the unit main body portion  2  only, from which the right outer casing panel  13 , the left outer casing panel  14 , the right-side cover  15  and the left-side cover  16  are removed for the purpose of clarity. 
   As shown in  FIG. 4 , the unit main body portion  2  is provided with a metal base plate  25 , on which the right-side cover  15 , the left-side cover  16  and the separation base  17  are fixed with screws. The base plate  25  is provided with a cassette pressing pin  26  for pressing, by a biasing force of a compression spring  27 , to a reference plane (not shown) of the right-side cover  15 . The feeding cassette  3 , being pressed by the cassette pressing pin  26 , is positioned in a lateral direction (transversal direction of the recording medium) with respect to the unit main body portion  2 . The cassette tray  24  is also provided, on a left lateral face thereof, with a recess (not shown) for accepting an end of the cassette pressing pin  26 , whereby a positioning is achieved also in the longitudinal direction (lengthwise direction of the recording medium). 
   On the base plate  25 , a grounding spring  28 , to be contacted with a chassis portion to be explained later of the main body  100  of the recording apparatus, is fixed on the left-side cover  16  which is omitted in the drawing. A feeding roller rubber (feeding roller)  29  is pressed into a part of the axial direction of a feeding roller shaft  33 . A transfer roller  32  is positioned at a downstream side of the feeding roller rubber  29  in a feeding direction of the recording medium  51 , and is formed by two rubber roller portions integrally fixed on a metal rotary shaft. Pinch rollers  38  are provided in positions corresponding to the roller portions of the transfer roller  32 , and are pressed to the roller portions by a spring shaft (not shown) under a pressing force of about 100 gf. The transfer roller  32  is rocked by a transfer roller rocking mechanism to be explained later, and is switched between a contact state and a non-contact state to the pinch rollers  38 . 
     FIG. 5  is a cross-sectional view of the feeding roller rubber  29 , sectioned at the center in the axial direction, showing an initial state in which the pressure plate  8  is lowered.  FIG. 6  is a cross-sectional view showing a state in the course of feeding of the recording medium, in which the pressure plate  8  is elevated.  FIGS. 5 and 6  show the feeding cassette  3  and the recording medium  41  in addition to the unit main body portion  2  shown in  FIG. 4 .  FIG. 7  is a perspective view showing the first pressure plate pressing plate and the second pressure plate pressing plate in a state shown in  FIG. 6 , wherein some components are omitted for the purpose of clarity. 
   The unit main body portion  2  is provided with a feeding mechanism for feeding the recording medium  41  and a separating mechanism for separating the recording medium one by one. In the following, configurations of the feeding mechanism and the separating mechanism will be explained with reference to  FIGS. 4 to 7 . 
   The feeding mechanism provided in the unit main body portion  2  includes, as shown in  FIGS. 5 and 6 , a first pressure plate pressing metal plate  30  (first movable plate) for vertically moving the pressure plate  8  in contact therewith, and a second pressure plate pressing metal plate  39  (second movable plate) for rotating the first pressure plate pressing plate  30 . The second pressure plate pressing metal plate  39  is formed into an approximately square-U shape and is partly positioned under the separation base  17 . 
   The separating mechanism constituting medium separating means provided in the unit main body portion  2  includes a separating pad  37  to be contacted with the recording medium  41 , a separating pad holder  36  capable of rotating the separating pad  37  between a contact position contacted with the recording medium and a non-contact position separated therefrom, and a rocking plate  31  for rotating the separating pad holder  36 . 
   The separating pad  37  is formed by a foamed urethane material having a friction coefficient of 1.1 or higher to the recording medium  41 . The separating pad  37  is adhered, for example with a double-side adhesive tape, on the separating pad holder  36 . The separating pad holder  36  is provided rotatably about a rotary shaft  40  provided on the separation base  17 . In an initial state ( FIG. 5 ), the separating pad holder  36  is rotated clockwise by a weight thereof and is stopped in contact with a stopper (not shown) provided on the separation base  17 , thereby being maintained in a separated position in which the separating pad  37  is separated from the feeding roller rubber  29 . 
   Below the separating pad holder  36 , a separating pad shaft  35  is fitted in a hole provided in the separation base  17  and is rendered movable in a vertical direction in  FIG. 5 . On the external periphery of the separating pad shaft  35 , there is provided a compression coil spring  34 , into which the separating pad shaft  35  is inserted. The compression coil spring  34  impinges at a lower end thereof on the separation base  17  while improves at an upper end thereof on a flange portion of the separating pad shaft  35 , thereby applying an upward biasing load of about 50 to 100 gf to the separating pad shaft  35 . The separating pad shaft  35  is provided, at a lower end thereof, with a larger diameter portion which engages with a U-shaped engaging portion (not shown) formed in the rocking plate  31 . 
   The rocking plate  31  is provided rotatably about a rotary shaft  42  supported by the base plate  25 . In a state shown in  FIG. 5 , the rocking plate  31  is pressed by a pressing portion  46  to be explained later and is maintained in a substantially horizontal position. 
   The second pressure plate pressing plate  39  is supported, at a base end thereof, rotatably about a rotary shaft  43  provided on the base plate  25 , and is maintained, at a front end portion  44 , in contact with the first pressure plate pressing plate  30  as shown in  FIGS. 6 and 7 . The second pressure plate pressing plate  39 , upon being rotated, rotates and lifts the first pressure plate pressing plate  30  from the base plate  25 . 
   The first pressure plate pressing plate  30  is inserted, at a bent portion  45  formed at an end, into a hole in the base plate  25  and is rendered rotatable about such bent portion  45 . Therefore, an upward rotation of the second pressure plate pressing plate  39  causes an upward rotation of the first pressure plate pressing plate  30 . Since the first pressure plate pressing plate  30  is contacted with the pressure plate  8  as described above, the pressure plate  8  can be moved vertically between the contact position and the separated position by the rotation of the second pressure plate pressing plate  39 . 
     FIG. 6  shows a state where the pressure plate  8  is elevated to contact the recording medium  41  with the feeding roller rubber  29  for feeding the recording medium  41 . The second pressure plate pressing plate  39  is provided with a pressing portion  46  for pressing a part of the rocking plate  31 , and, when the second pressure plate pressing plate  39  is rotated upward from the horizontal state, the rocking plate  31  is also lifted by rotation, whereby the separating pad shaft  35  slides upwards by the load of the compression coil spring  34 . As the separating pad shaft  35  lifts a lower face of the separating pad holder  36 , whereby the separating pad  37  is pressed to the feeding roller rubber  29 . The rocking plate  31  no longer rotates at this point, and a further lifting of the second pressure plate pressing plate  39  shifts the contact load of the separating pad  37  to about 50 gf. 
   Then, reference is made again to  FIG. 4  for explaining the second pressure plate pressing plate  39 , the feeding roller shaft  33 , the transfer roller  32  and the transfer roller rocking mechanism. 
   As shown in  FIG. 4 , a right-side chassis  48  and a left-side chassis  49  are fixed on the base plate  25  with screws. The right-side chassis  48  includes a stepping motor  50  as a driving source for transmitting a driving power to the pressure plate  8  and the feeding roller rubber  29 . The stepping motor  50  is controlling in a forward rotating direction or a reverse rotating direction, by a control circuit portion  130  ( FIG. 18 ), constituting control means provided in the main body  100  of the recording apparatus. 
   The control circuit portion  130  also controls an LF motor  131 , a carriage  106  and a recording head  106   a  to be explained later. 
     FIG. 8  is a lateral view of a transfer roller rocking mechanism, provided on the right-side chassis  48 , seen from outside of the right-side chassis  48 . For facilitating the understanding, the stepping motor  50  is omitted in  FIG. 8 .  FIG. 8  shows an initial state prior to the start of feeding of the recording medium  41 , in which a transfer roller gear  67 , provided coaxially with the transfer roller  32 , is in a released state. 
   An idler gear  51  meshes with a drive gear (not shown) on a rotary shaft of the stepping motor  50 . As shown in  FIG. 8 , the idler gear  51  transmits the driving power of the stepping motor  50 , through an idler gear train  52 , respectively to first and second pendulum gear units  53 ,  54 . 
   At first the first pendulum gear unit  53  will be explained with reference to  FIG. 9  which is a magnified view of the vicinity of the first pendulum gear unit  53 . 
     FIG. 9  is a schematic view seen from the inside of the right-side chassis  48 .  FIG. 8  shows an initial state prior to the start of the feeding operation, while  FIG. 9  shows a state in the course of a feeding operation. 
   In the initial state, as shown in  FIG. 8 , the first pendulum gear unit  53  is rocked in a direction e in  FIG. 8 . Since the stepping motor  50  is reversed before reaching this initial state as will be explained later, the first pendulum gear unit  53  is rocked to this initial position. 
   The first pendulum gear unit  53  is rendered capable of a rocking motion about a rotation center of a solar gear  55 , and rotatably supports planet gears  56 ,  65  meshing with the solar gear  55 . Also in a position adjacent to the first pendulum gear unit  53 , there is provided a rocking cam gear  58 , which is provided at an end of a cam shaft  98  (cf.  FIG. 16 ) having a toothless portion  59 , a toothless portion  64  and a cam portion  60 . Such toothless portions  59 ,  64  are shifted in the axial direction of the cam shaft  98  of the rocking cam gear  58 , and the planet gears  56 ,  65  are also shifted in the axial direction of the rotary shaft, matching the positions of the toothless portions  59 ,  64 . 
   In the initial position of the first pendulum gear unit  53 , the planet gear  56  meshes with the rocking cam gear  58  through the solar gear  55 . In the first pendulum gear unit  53 , the rocking cam gear  58  is rotated by the rotation of the planet gear  56 , and, when the rocking cam gear  58  is rotated to a position where the toothless portion thereof corresponds to the planet gear  56 , the meshing state of the planet gear  56  and the rocking cam gear  58  is released. Therefore, even when the stepping motor  50  continues to be driven in the reverse direction, the driving power transmitted to the planet gear  56  is not transmitted to the rocking cam gear  58  to attain a power non-transmitting state, whereby the rocking cam gear  58  is stopped in a state shown in  FIG. 8 . As shown in  FIG. 8 , a rocking lever  61  has a cam follower portion  62  slidable along the cam portion  60  of the rocking cam gear  58 . By a displacement of the cam follower portion  62  along the cam portion  60  of the rocking cam gear  58 , the entire rocking lever  61  rocks about a lever shaft  63 . 
   In feeding the recording medium  41  by a forward rotation of the stepping motor  50  from the state shown in  FIG. 8 , the rocking cam gear  58  is rotated counterclockwise in  FIG. 8 . In such state, the first pendulum gear unit  53  is rocked in a direction f in  FIG. 9 , whereby the planet gear  65  meshes with the rocking cam gear  58  through the solar gear  55 . 
   In the first pendulum gear unit  53 , as in the case where the stepping motor  50  is rotated in the reverse direction, the rocking cam gear  58  is rotated by the rotation of the planet gear  65 , and, when the rocking cam gear  58  is rotated to a position where the toothless portion  64  thereof corresponds to the planet gear  65 , the meshing state of the planet gear  65  and the rocking cam gear  58  is released. Therefore, even when the stepping motor  50  continues to be driven in the forward direction, the driving power transmitted to the planet gear  65  is not transmitted to the rocking cam gear  58  to attain a power non-transmitting state, whereby the rocking cam gear  58  is stopped in a state shown in  FIG. 9 . 
   Thus, by rotating the stopping motor  50  in the forward direction and in the reverse direction, the planet gear  65  is reciprocated within a range of a rotation angle of 110°, and the rocking lever  61  is also reciprocated within a range of a rotation angle of 7.5°. The width of such rocking motion is determined by a mechanical configuration and does not require a precision in the stopping position of the stepping motor  50 . 
   As shown in  FIGS. 8 and 9 , the rocking lever  61  rotatably supports a transfer roller gear  67  fixed at an end of a shaft of the transfer roller  32 , and similar supports also a conveying idler gear  68 . 
   As shown in  FIGS. 4 and 16 , the left-side chassis  49  is provided with a rocking lever  96 , formed in a similar shape as the aforementioned rocking lever  61 .  FIG. 16  is a perspective view showing the vicinity of the left-side chassis  49 . As shown in  FIG. 16 , the other end of the shaft of the transfer roller  32  is supported rotatably by the rocking lever  96 . Also the cam shaft  98 , having the rocking cam gear  58  at an end, is provided with a cam portion  97  at the other end. The cam portion  97  has a cam shape similar to that of the cam portion  60  of the rocking cam gear  58 , and is rotated through the cam shaft  97  by the rotation of the rocking cam gear  58 . 
   Therefore, the transfer roller  32 , supported by the rocking levers  61 ,  96  respectively provided in the right-side chassis  48  and the left-side chassis  49 , executes a rocking motion in a direction of approaching to and being separated from the pinch roller  38  by the rocking motion of the rocking levers  61 ,  96 . The rocking lever  61 , the rocking lever  96 , the idler gear  51 , the idler gear train  52 , the first pendulum gear unit  53 , the rocking cam gear  58  and the cam portion  60  constitute contact/separating means which contacts and separates the transfer roller  32  and the pinch roller  38 . 
   Then, the other second pendulum gear unit  54  will be explained with reference to  FIG. 10  which is a schematic view showing a state in the course of feeding and seen from the inside of the right-side chassis  48  as in  FIG. 9 . 
   The second pendulum gear unit  54  has a rocking center coaxial with the rocking center of the rocking lever  61 . During a feeding operation in which the stepping motor  50  is rotated in the forward direction, the second pendulum gear unit  54  is rocked in a direction g 1  in  FIG. 10  and a planet gear  70  meshes with a transfer roller gear  67 . 
   When the stepping motor  50  is rotated in the reverse direction, the second pendulum gear unit  54  rocks in a direction g 2  in  FIG. 10 , whereby a planet gear  71  meshes with a transfer idler gear  68 . Even when the rocking lever  61  is rocked, the second pendulum gear unit  54  and the rocking lever  61  are so constructed as to mutually impinge and to be determined in position by a stopper (not shown). 
   Thus, regardless of the rotating direction of the stepping motor  50  in the forward or reverse direction, the transfer roller gear  67  is constantly rotated in a direction (clockwise in  FIG. 10 ) for transferring the recording medium  41  toward the main body  100  of the recording apparatus. The idler gear  51 , the idler gear train  52 , the second pendulum gear unit  54 , the transfer gear roller  67  and the idler gear  68  constitute third drive transmission means. 
   In the following, there will be explained the driving power transmission by the second pressure plate pressing plate  39  and the feeding roller shaft  33 . 
   As shown in  FIG. 8 , the idler gear  51  receiving the driving power from the stepping motor  50  transmits the driving power through an idler gear  73  to a gear train provided inside the right-side chassis  48 . 
     FIG. 11  is a perspective view showing the inside of the right-side chassis  48 , omitting certain components for the purpose of clarity. As shown in  FIG. 11 , an idler gear  73  meshing with the idler gear  73  is provided inside the right-side chassis  48 . The idler gear  74  meshes with a solar gear  76  provided in a pressure plate pendulum gear unit  75  for transmitting the driving power of the stepping motor  50  to the feeding roller rubber  29 . The pressure plate pendulum gear unit  75  is provided with a first planet gear  77  and a second planet gear  78  respectively meshing with the solar gear  76 .  FIG. 11  shows an initial state prior to a feeding, in which the planet gear  78  and the pressure plate idler gear  79  are stopped in a mutually meshing state.  FIG. 12  is a detailed perspective view showing such state seen from the rear side. 
   As shown in  FIGS. 11 and 12 , in a position adjacent to the pressure plate pendulum gear unit  75 , there is provided the pressure plate cam gear  80  for controlling the vertical movement of the pressure plate  8 , explained in the foregoing with reference to  FIGS. 5 and 6 . The pressure plate cam gear  80  is constructed as a two-step gear, having an external gear portion  83  and an internal gear portion  84 . The external gear portion  83  is provided with toothless portions  81 ,  82  for achieving a power non-transmitting state, in positions displaced in the axial direction. The idler gears  73 ,  74 , the pressure plate pendulum gear unit  75 , the pressure plate cam gear  80  etc. constitute first drive transmission means. 
   In the state shown in  FIGS. 11 and 12 , the pressure plate idler gear  79  is positioned corresponding to the second toothless portion  82  and is in a non-transmitting state. The internal gear portion  84  of the pressure plate cam gear  80  meshes with a feeding idler gear  99  which meshes with a gear portion  33   a  provided integrally at an end of the feeding roller shaft  33 . Therefore, the pressure plate cam gear  80 , upon being rotated, transmits the driving power to the feeding roller shaft  33 . Consequently, the feeding roller shaft  33  and the feeding roller rubber  29  are rotated and stopped in synchronization with the up-down operation of the pressure plate  8 . The idler gears  73 ,  74 , the pressure plate pendulum gear unit  75 , the pressure plate cam gear  80 , the feeding idler gear  99  and the gear portion  33   a  of the feeding roller shaft  33  constitute second drive transmission means. 
   As shown in  FIGS. 7 and 11 , a metal wire  88  engages at an end thereof with a wire engaging portion  87  of the aforementioned second pressure plate pressing plate  39 , then is wound on a wire pulley (direction converting means)  89  supported on a shaft  94  to be explained later by about 90° and engages on the other end with an end of a pressure plate coil spring  90  constituting pressure plate contact means. The other end of the pressure plate coil spring  90  engages with a spring engaging piece  91  formed by bending a part of the base plate  25 . Therefore, the biasing direction of the pressure plate coil spring  90  is approximately perpendicularly converted in by the wire  88  and the wire pulley  89  and is applied to the second pressure plate pressing plate  39 . 
   In this manner, the second pressure plate pressing plate  39  is given a load of about 1.3 kg by the pressure plate coil spring  90  through the wire  88 , and, as explained in  FIGS. 5 and 6 , such load is finally converted into a contact power for pressing the pressure plate  8  to the feeding roller rubber  29 . Such pressing load is set at about 250 gf in consideration of a lever ratio and the weight of the recording medium  41 . However, in a state shown in  FIG. 11 , a cam portion  92  provided in the pressure plate cam gear  80  impinges on an end of the second pressure plate pressing plate  39 , which is restricted downwards by such cam portion  92 , so that the pressure plate  8  is in a lowered position. 
   When a feeding operation is initiated from the state shown in  FIGS. 11 and 12  and the stepping motor  50  is rotated in the forward direction, the pressure plate pendulum gear unit  75  is rocked in a direction h in  FIG. 12  whereby the first planet gear  77  meshes with the external gear portion  83  of the pressure plate cam gear  80 , which thus starts to be rotated clockwise in  FIG. 12 . 
     FIG. 13  is a perspective view showing a state where the pressure plate cam gear  80  is rotated by a small amount (pressure plate coil spring  90 , wire  88  etc. being omitted from the illustration). The cam portion  92  of the pressure plate cam gear  80  is rotated in a direction m in  FIG. 13  to eliminate restriction on the second pressure plate pressing plate  39 , which is therefore lifted at an end thereof by the biasing force of the pressure plate coil spring  90 . 
   In this state, the pressure plate cam gear  80  tends to rotate by the load of the spring, and, in order to avoid a situation where such load is transmitted to the pressure plate pendulum gear unit  75  to separate the planet gear  77  from the pressure plate cam gear  80  and to interrupt the transmission of the driving power, the pressure plate cam gear  80  is provided with a cam portion  80  also on a rear side thereof as shown in  FIG. 12 . Such cam portion  85  impinges on an end of a projection  86  provided in the pressure plate pendulum gear unit  75  to limit the position thereof, thereby preventing separation of the first planet gear  77  from the pressure plate cam gear  80 . 
   The cam portion  85  is required only in a section in the contracting direction of the pressure plate coil spring  90 , namely a section in which the pressure plate  8  is elevated to contact the feeding roller rubber  29 , so that the cam portion  85  is provided corresponding to such section. In response to the continued rotation of the pressure plate cam gear  80 , the second pressure plate pressing plate  39  is once elevated and is then lowered again. When the pressure plate cam gear  80  is rotated to a rotational position shown in  FIG. 14 , the first toothless portion  81  reaches a state opposed to the first planet gear  77 , thereby reaching a power non-transmitting state. 
   Within a period from the initial state shown in  FIG. 11  to the power non-transmitting state, the pressure plate cam gear  80  is rotated by an angle of 320°. The feeding operation for a recording medium  41  is completed by the operations up to this point, and is thereafter transferred to the main body  100  of the recording apparatus by the transfer roller  32  only. By rotating the stepping motor  50  in the reverse direction in this state, the second planet gear  78  then meshes with the pressure plate idler gear  79  and the pressure plate cam gear  80  is rotated by the pressure plate idler gear  79  in a direction m by an angle of 40°. Thus the pressure plate cam gear  80  is again moved to a position where the second toothless portion  82  is opposed to the pressure plate idler gear  79 , thereby returning to the initial state. Therefore, the pressure plate cam gear  80  is constantly rotated in a direction m regardless whether the stepping motor  50  is rotated in the forward or reverse direction. 
     FIG. 15  is a perspective view showing a support structure of the wire pulley  89 , omitted in  FIG. 11 . As shown in  FIG. 15 , on the base plate  25 , there is provided a supporting plate  93  on which a shaft  94  for supporting the wire pulley, on which the wire  88  is wound, and a shaft  95  rotatably supporting the pressure plate cam gear  80  provided inside the right-side chassis  48  are fixed by caulking. The wire pulley  89  is caulked integrally in an axially fixed position by a flange of the shaft  94 . 
   In the following, there will be explained a schematic configuration when the main body  100  of the recording apparatus is mounted on the cassette feeding unit  1 .  FIG. 1  is a perspective view showing a recording apparatus formed by mounting the main body  100  on the cassette feeding unit  1 , and  FIG. 17  is a cross-sectional view along a plane X in  FIG. 1  and showing principal components only. 
   The main body  100  of the recording apparatus includes a recording portion for recording on the recording medium  41 , a conveying portion for conveying the recording medium, fed from the cassette feeding unit  1 , to the recording portion, and a discharge portion for discharging the recording medium  41 , recorded in the recording portion, to the exterior of the apparatus. 
   As shown in  FIG. 17 , the conveying portion of the main body  100  of the recording apparatus is provided with an LF roller (conveying means)  102  for intermittently conveying, in a conveying path, the recording medium  41  fed by the cassette feeding unit  1 . A pinch roller  103  is pressed with a predetermined load to the LF roller  102 . The pinch roller  103  is provided in plural units along a main scanning direction, and correctly conveys the recording medium  41  in a sub scanning direction. 
   In the conveying path of the recording medium  41 , for detecting a leading end and a trailing end thereof in the conveying direction, a PE (paper end) sensor lever  104  constituting detection means is provided rotatably. A lower end of the PE sensor lever  104  is rocked when a leading end or a trailing end of the recording medium  41  passes, and a transmissive photosensor  104   a  detects a movement of an upper end of the PE sensor lever  104 , thereby detecting the passing time of the recording medium  41 . 
   The recording medium  41  extracted by the feeding roller rubber  29  as explained in the foregoing, after separation into a single sheet, is transferred by the transfer roller  32  along a direction j in  FIG. 17  into the main body  100  of the recording apparatus. The recording medium  41  transferred along a direction j passes through a guide member, is intermittently conveyed by being pinched between the LF roller  102  and the pinch roller  103 , and is subjected to a recording operation by an ink discharge from an ink jet recording head  106   a  constituting recording means and mounted on a carriage  106  moving in a scanning motion in the main scanning direction. The recording medium  41  after the recording operation is supported by a discharge roller  107  and a spur  108  provided in the conveying portion of the main body  100  and is discharged to the exterior of the recording apparatus. 
   In the following, there will be explained, with reference to  FIG. 19 , the recording operation in the recording apparatus in a state where the cassette feeding unit  1  is mounted on the main body  100  of the recording apparatus. 
   The operation starts from a step S 0 , and at first a step S 1  causes the control means  130  to rotate the stepping motor  50  in the forward direction. 
   The forward rotation of the stepping motor  50  is transmitted, through the idler gears  51 ,  73  to the idler gear  74 . The rotation of the idler gear  74  is transmitted through the solar gear  76  band the planet gear  77  of the pressure plate pendulum gear unit  75 , to the pressure plate cam gear  80 , which in response starts to rotate clockwise in  FIG. 12 . The second pressure plate pressing plate  39 , being freed from the restriction by the cam portion  92  of the pressure plate cam gear  80 , is lifted at an end by the biasing force of the pressure plate coil spring  90 , whereby the pressure plate  8  is elevated and the recording medium is brought into contact with the feeding roller rubber  29 . 
   The forward rotation of the stepping motor  50  is also transmitted, through the internal gear portion  84  of the pressure plate cam gear  80  and the feeding idler gear  99 , to the gear portion  33   a  of the feeding roller shaft  33 , thereby rotating the feeding roller  29  and feeding the recording medium  41 . 
   The forward rotation of the stepping motor  50  is also transmitted, through the idler gear  51  and the idler gear train  52 , to the solar gear  55  of the first pendulum gear unit  53 . The rotation of the solar gear  55  is transmitted to the planet gear  65  and the rocking cam gear  58 , and the rotation of the cam portion  60  rotating integrally with the rocking cam gear  58  rotates the rocking lever  61  clockwise ( FIG. 8 ) about the lever shaft  63 , thereby pressing the transfer roller  32  to the pinch roller  38 . When the transfer roller  32  is pressed to the pinch roller  38 , the planet gear  65  is opposed to the toothless portion  64  of the rocking cam gear  58 , whereby the rocking cam gear  58  is stopped. 
   The forward rotation of the stepping motor  50  is also transmitted, through the idler gear  51  and the idler gear train  52 , to the solar gear  54   a  of the second pendulum gear unit  54 . The second pendulum gear unit  54  rotates in a direction g 1  ( FIG. 10 ), and the rotation of the solar gear  54   a  in the direction g 1  is transmitted through the planet gear  70  to the transfer roller gear  67 , whereby the transfer roller  32  rotates clockwise in  FIG. 6 . 
   The recording medium  41  fed by the feeding roller  29  is conveyed, by the transfer roller  32  rotating in contact with the pinch roller  38 , along a direction j in  FIG. 17  into the main body  100  of the recording apparatus. 
   After the recording medium  41  reaches the transfer roller  32 , the cam portion  92  of the pressure plate cam gear  80  in rotation presses down the second pressure plate pressing plate  39 , whereby the pressure plate  8  is lowered and the recording medium  41  is separated from the feeding roller rubber  29 . The recording medium  41  is conveyed, by the transfer roller  32 , toward the LF roller  102  along a curved conveying path  120  in the main body of the recording apparatus. The pressure plate cam gear  80  rotates and stops at a position where the toothless portion  81  is opposed to the planet gear  77 . In this state, the pressure plate  8  is in a lowest position. 
   In a step S 2 , after the leading end of the recording medium  41  is detected by the PE sensor lever  104 , the transfer roller  32  advances the recording medium  41  by a distance from the PE sensor lever  104  to the LF roller  102  plus 10 mm. In this state, the recording medium  41  impinges on a contact portion between the LF roller  102  and the pinch roller  103  and then forms a loop, thereby securely maintaining the leading end of the recording medium  41  parallel to the LF roller  102  and preventing so-called skewed recording. The recording medium  41  is conveyed by 300 mm at maximum, until the leading end is detected by the PE sensor. 
   A step S 3  discriminates whether the leading end of the recording medium  41  is detected by the PE sensor, and, if not, the flow proceeds to a step S 4  to restore the initial state by reversing the stepping motor  50  by the control circuit portion  130 . Then a step S 5  discriminates whether the feeding operation is of second time, and, if so, a step S 13  displays an error message for absence of the recording medium on a display panel (not shown) provided on the recording apparatus. In case the feeding operation is not of second time, the stepping motor  50  is rotated in the forward direction again to start the feeding operation from the step S 1 . 
   On the other hand, in case the step S 3  identifies that the leading end of the recording medium  41  is detected by the PE sensor, the transfer roller  32  conveys the recording medium  41  by a distance to the LF roller  102  plus 10 mm, and then a step S 6  causes the control circuit portion  130  to rotate the stepping motor  50  in the forward direction and also to drive an LF motor  13  for rotating the LF roller  102 . In this manner the LF roller  102  is matched with the transfer speed of the transfer roller  102  and the recording medium  41  is conveyed for 12 mm in synchronization by the transfer roller  32  and the LF roller  102 . 
   A step S 7  causes the LF roller  102  to convey the recording medium  41  further to a recording start position, then steps the LF roller  102  and simultaneously reverses the stepping motor  50  whereupon the pressure plate cam gear  80  is rotated by an angle of 40° thereby returning to the initial position and is thus stopped. In such initial state, the transfer roller  32  is separated from the pinch roller  38 , and, because of absence of a pulling resistance from the upstream side to the intermittent conveying operation by the LF roller  102 , the LF roller  102  can maintain a satisfactory accuracy of conveying. Then a step S 8  repeats a conveying operation by the LF roller  102  and a recording operation by the recording head  106   a  associated with the scanning motion of the carriage  106 , thereby executing a recording on the recording medium  41 . 
   A step S 9  discriminates whether the recording is terminated in one page, and, if not, the flow returns to the step S 8  to continue the recording operation. In case the recording is to be terminated, after the trailing end of the recording medium  41  is detected by the PE sensor lever  104 , a step S 10  conveys the recording medium by 120 mm, thereby discharging the recording medium  41  from the recording apparatus. The conveying is executed for 600 mm at maximum, until the trailing end of the recording medium  41  is detected by the PE sensor. A step S 11  discriminates whether the trailing end of the recording medium  41  is detected by the PE sensor, and, if not, a step S 12  displays a jam error for a paper jamming, but, if detected, the recording medium is discharged by conveying over 120 mm, and the sequence is terminated in a step S 14 . 
   Second Embodiment 
   In the foregoing first embodiment, the rocking levers  61 ,  96  are used to rock the transfer roller  32  thereby avoiding a detrimental influence on the conveying operation by the LF roller  102 , but it is not essential to completely rock the transfer roller  32  for removing the load of the transfer roller  32  as in the first embodiment. 
     FIG. 20  is a perspective view showing the vicinity of the transfer roller in the second embodiment. As shown in  FIG. 20 , a transfer roller  301  is fixed to a transfer roller gear  300  of a defined rotating direction. The transfer roller gear  300  is rotatably supported by a right-side chassis  302 . The other end of the shaft supporting the transfer roller  301  is supported by a left-side chassis (not shown). 
   In the right-side chassis  302 , there is also provided a pendulum gear unit (third drive transmission means)  303  for transmitting the driving power to the transfer roller gear  300 . The transfer roller gear  300  meshes with a planet gear  304  of the pendulum gear unit  303 .  FIG. 19  shows a state where a stepping motor  307  is rotated in the forward direction to transmit the driving power from the pendulum gear unit  303  through an idler gear train  306  to the transfer roller gear  300  and a phase where the recording medium  41  is transferred to the LF roller  107  as in the first embodiment. 
   When the leading end of the recording medium  41  reaches the LF roller  107  and the stepping motor  307  is rotated in the reverse direction, the pendulum gear unit  202  is rocked in a direction k in  FIG. 19  and is stopped by impinging on a stopper (not shown) provided on the right-side chassis  302 . Thus a planet gear  304  is separated from the transfer roller gear  300  and is freed from the meshing state therewith, thereby reaching a power non-transmission state in which the driving power of the stepping motor  307  is not transmitted. 
   Therefore, during an intermittent conveying operation by the LF roller  107 , the transfer roller  301  is driven by the LF roller  107 . The transfer roller  301  can be driven satisfactorily, though an inertial load at such drive and a dynamic frictional load at the bearings in the left- and right-side chassis are added, since such additional loads are small. 
   Thus, in comparison with the first embodiment, the second embodiment allows to dispense with the rocking lever, the cam gear, the idler gear etc. for rocking the transfer roller thereby simplifying the entire configuration of the cassette feeding unit and the recording apparatus and reducing the production cost. 
   This application claims priority from Japanese Patent Application No. 2003-306413 filed Aug. 29, 2003, which is hereby incorporated by reference herein.