Abstract:
There is provided provide a tape printing apparatus which is capable of properly operating a tape feed mechanism and a tape cutting mechanism by the use of a single motor. The tape printing apparatus is capable of printing on a printing tape while feeding the printing tape by unwinding a roll of the printing tape, and cutting off a printed portion of the printing tape. A tape feed mechanism feeds the printing tape. A tape cutting mechanism cuts the printing tape. A single motor is capable of performing rotation in normal and reverse directions. A feed mechanism-side gear train transmits torque of the motor to the tape feed mechanism to cause the tape feed mechanism to operate. A cutting mechanism-side gear train transmits the torque of the motor to the tape cutting mechanism to cause the tape cutting mechanism to operate. A clutch mechanism is interposed between the motor, and the feed mechanism-side gear train and the cutting mechanism-side gear train, for performing switching operation to selectively transmit the torque of the motor in one of the normal and reverse directions to the feed mechanism-side gear train, and the torque of the motor in another of the normal and reverse directions to the cutting mechanism-side gear train.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a tape printing apparatus which is capable of printing on a printing tape while feeding the printing tape from a tape cartridge loaded therein and cutting off the printed portion of the printing tape. 
     2. Prior Art 
     In a conventional tape printing apparatus, a tape cartridge containing a roll of a printing tape and a roll of an ink ribbon is removably loaded in a main unit of the apparatus. The main unit contains a print head which faces the tape cartridge loaded in the main unit, a tape feed mechanism for simultaneously feeding both the printing tape and the ink ribbon, and a tape cutting mechanism for cutting off a printed portion of the printing tape. The tape feed mechanism feeds the printing tape and the ink ribbon in a state placed one upon the other, and the print head faces toward the printing tape and the ink ribbon fed by the tape feed mechanism, for printing on the printing tape as desired. During the printing operation, used part of the ink ribbon is taken up within the tape cartridge, and a printed portion of the printing tape alone is sent out of the main unit via a tape exit. When the printing operation is completed, the printed portion of the printing tape is cut off by the tape cutting mechanism and discharged from the apparatus. The tape feed mechanism and the tape cutting mechanism each include a motor as a drive source, and are subject to centralized control by a controller. 
     In the above conventional tape printing apparatus, the tape feed mechanism and the tape cutting mechanism as output ends of the driving system of the apparatus are different in the manner and timing of operation, and therefore the two mechanisms are required to be driven by respective different motors. This results in an increase in the number of component parts and space for installation of the same. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a tape printing apparatus which is capable of properly operating a tape feed mechanism and a tape cutting mechanism by the use of a single motor. 
     To attain the above object, the present invention provides a tape printing apparatus a tape printing apparatus which is capable of printing on a printing tape while feeding the printing tape by unwinding a roll of the printing tape, and cutting off a printed portion of the printing tape. 
     The tape printing apparatus according to the invention is characterized by comprising: 
     a tape feed mechanism for feeding the printing tape; 
     a tape cutting mechanism for cutting the printing tape; 
     a single motor which is capable of performing rotation in normal and reverse directions; 
     a first torque transmitting mechanism for transmitting torque of the motor to the tape feed mechanism to cause the tape feed mechanism to operate; 
     a second torque transmitting mechanism for transmitting the torque of the motor to the tape cutting mechanism to cause the tape cutting mechanism to operate; and 
     a clutch mechanism interposed between the motor, and the first torque transmitting mechanism and the second torque transmitting mechanism, for performing switching operation to selectively transmit the torque of the motor in one of the normal and reverse directions to the first torque transmitting mechanism, and the torque of the motor in another of the normal and reverse directions to the second torque transmitting mechanism. 
     According to this tape printing apparatus, when the motor performs normal rotation, for instance, the torque of the motor is transmitted by the clutch mechanism via the first torque transmitting mechanism to the tape feed mechanism to feed the tape, while when the motor performs reverse rotation, the torque of the motor is transmitted by the clutch mechanism via the second torque transmitting mechanism to the tape cutting mechanism to cut off the printed portion of the tape. That is, it is possible to feed the printing tape by rotation of the motor in one direction and cut off the printed portion of the tape by rotation of the same in the other direction. 
     Preferably, the tape printing apparatus includes an output gear from which the torque of the motor is output, and a rotational shaft on which the output gear is rigidly fitted, the first torque transmitting mechanism including a feed mechanism-side gear train for transmitting the torque of the motor to the tape feed mechanism, the feed mechanism-side gear train having an input gear, the second torque transmitting mechanism including a cutting mechanism-side gear train for transmitting the torque of the motor to the tape cutting mechanism, the cutting mechanism having an input gear, the clutch mechanism including a planet gear mating with the output gear, and a carrier having one end thereof supporting the planet gear such that the planet gear is rotatable thereon and another end thereof loosely fitted on the rotational shaft on which the output gear is rigidly fitted such that the carrier is capable of pivotal movement, by frictional drag, with rotation of the rotational shaft, the planet gear being mated with the input gear of the feed mechanism-side gear train by the rotation of the motor in the one of the normal and reverse directions, and mated with the input gear of the cutting mechanism-side gear train by the rotation of the motor in the another of the normal and reverse directions. 
     According to this preferred embodiment, when the motor performs the normal rotation, for instance, the carrier of the clutch mechanism pivotally moves or swings in one direction, by frictional drag, with rotation of the rotational shaft on which the output gear is fitted to cause the planet gear to automatically mate with the input gear of the feed mechanism-side gear train, whereby torque of the output gear is transmitted to the input gear of the feed mechanism-side gear train via the planet gear. On the other hand, when the motor performs the reverse rotation, the carrier of the clutch mechanism pivotally moves or swings in the other direction, by frictional drag, with rotation of the rotational shaft on which the output gear is fitted to cause the planet gear to automatically mate with the input gear of the cutting mechanism-side gear train, whereby the torque of the output gear is transmitted to the input gear of the cutting mechanism-side gear train via the planet gear. As described above, the switching between the normal and reverse rotations of the motor causes automatic switching of the clutch mechanism, and hence the supply of the driving force can be automatically switched. Further, the use of the planet gear permits the clutch mechanism to be simplified in construction. 
     Preferably, the tape printing apparatus includes an ink ribbon to be fed in a state placed upon the printing tape, the tape feed mechanism including a platen for feeding the printing tape and the ink ribbon in a state placed one upon another, a platen shaft for rotating the platen, a ribbon take-up reel for taking up the ink ribbon, and a ribbon take-up shaft for rotating the ribbon take-up reel, the feed mechanism-side gear train including a platen gear on which the platen shaft is coaxially secured and a take-up gear on which the ribbon take-up shaft is coaxially secured, as respective output ends thereof. 
     According to this preferred embodiment, by rotating the platen shaft and the ribbon take-up shaft via the platen gear and the take-up gear, respectively, the printing tape and the ink ribbon can be properly fed together in a state placed one upon the other. 
     More preferably, the tape cutting mechanism includes a stationary blade and a movable blade that perform relative motion therebetween for cutting operation, and a crank disk for engaging with the movable blade to cause the movable blade to effect the cutting operation, and the cutting mechanism-side gear train includes a cutter gear coaxially secured to the crank disk as an output end of the cutting mechanism-side gear train. 
     According to this preferred embodiment, by rotating the crank disk via the cutter gear, it is possible to cause the movable blade to perform a proper cutting operation. It is preferable that the stationary blade and the movable blade form a cutter in the form of scissors. 
     Further preferably, the tape printing apparatus includes a tape exit from which the printed portion of the printing tape is discharged, and a tape holding mechanism associated with the tape exit and linked to the tape cutting mechanism, for holding the printed portion cut off by the tape cutting mechanism at the tape exit. 
     Still more preferably, the tape printing apparatus includes a control block for controlling the rotation of the motor, and the control block controls the rotation of the motor such that when the movable blade has reached a cutting terminal portion as an end position in a cutting direction of the movable blade by the rotation of the motor in the another of the normal and reverse directions, the printed portion is held at the tape exit by the tape holding mechanism. 
     Even further preferably, the tape printing apparatus includes a printing block for printing on the printing tape, the motor including a rotational shaft, the crank disk having a peripheral surface and a recess formed in the peripheral surface, the recess having an arcuate profile in cross-section, the control block including an encoder arranged in proximity to the rotational shaft of the motor, for detecting a rotational angle through which the rotational shaft of the motor rotates, and a detection switch in abutment with the peripheral surface of the crank disk, the detection switch moving into the recess when the movable blade has reached a cutting wait position, and generating a cutting wait position detection signal indicative of the cutting wait position of the movable blade, the control block causing the motor to rotate in the another of the normal and reverse directions in response to a print command to thereby cause the movable blade to be pivotally moved to the cutting wait position, and in response to the cutting wait position detection signal, causing the motor to rotate in the one of the normal and reverse directions to thereby cause the movable blade to be held at the cutting wait position and at the same time cause the tape feeding mechanism to feed the printing tape, and upon termination of the printing, the control block causing the motor to rotate in the another of the normal and reverse directions to cause the movable blade to be pivotally moved from the cutting wait position to the cutting terminal position until the encoder detects a predetermined rotational angle through which the rotational shaft of the motor has rotated when the movable blade has reached the cutting terminal position, and then causing the motor to stop to thereby cause the tape holding mechanism to hold the printed portion of the printing tape at the tape exit. 
     The above and other objects, features, and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a tape printing apparatus according to an embodiment of the invention; 
     FIG. 2 is a perspective view of a cartridge compartment of the FIG. 1 tape printing apparatus and component parts associated with the cartridge compartment, as viewed from a cutter side; 
     FIG. 3 is a perspective view of the FIG. 2 cartridge compartment and component parts associated therewith, as viewed from a motor side; 
     FIG. 4 is a perspective view of a whole drive system of the FIG. 1 tape printing apparatus; 
     FIG. 5 is a perspective view of a gear train of the FIG. 4 drive system; 
     FIGS. 6A and 6B are enlarged plan views of a clutch mechanism of the FIG. 4 drive system and component parts associated with the clutch mechanism; 
     FIG. 7 is an enlarged perspective view of a tape cutting mechanism of the FIG. 4 drive system and component parts associated with the tape cutting mechanism; 
     FIG. 8 is a perspective view of a tape strip-holding mechanism of the FIG. 1 tape printing apparatus and component parts associated with the tape strip-holding mechanism; and 
     FIGS. 9A and 9B are enlarged plan views of the FIG. 8 tape strip-holding mechanism and component parts associated therewith. 
    
    
     DETAILED DESCRIPTION 
     The invention will now be described in detail with reference to drawings showing a tape printing apparatus according to an embodiment thereof. The tape printing apparatus prints on a strip of printing tape as desired according to key entries and cuts off the printed portion of the printing tape. The cut-off strip of the printing tape is used as a label to be affixed to a file, a cable, or the like. That is, the tape printing apparatus makes a label printed with characters from plain printing tape. The plain printing tape and an ink ribbon to be consumed in the tape printing are contained in a tape cartridge, and fed to the main unit of the apparatus from the tape cartridge. 
     Referring first to FIG. 1, the tape printing apparatus  1  is a hand-held type whose main unit  2  has an apparatus casing  3  forming an outer shell of the main unit  2 . The tape printing apparatus  1  has a key entry block  4  arranged at a front portion thereof and a lid  6  arranged at a rear portion thereof. The lid  6  incorporates a liquid crystal display  5  forming the outer surface of the lid  6 . As shown in FIGS. 2 and 3, arranged under the lid  6  is a cartridge compartment  8  for accommodating a tape cartridge  7 . Further, the apparatus casing  3  has a left side portion thereof formed with a tape exit  10  for communication between the cartridge compartment  8  and the outside of the apparatus  1 , and a cutter  11  faces the tape exit  10 , for cutting off a dispensed portion of the printing tape T (see FIGS.  1  and  2 ). 
     In the cartridge compartment  8 , there are erected a print head  14  covered with a head cover  13 , a platen shaft  15  opposed to the print head  14 , a take-up shaft  16  for taking up used part of the ink ribbon, and a guide projection  17  for guiding the tape cartridge  7  in the cartridge compartment  8  when it is mounted therein. A platen  18  for engagement with the platen shaft  15  is arranged in the tape cartridge  7  (see FIG.  1 ). 
     The platen  18 , the platen shaft  15 , and the take-up shaft  16  form a tape feed mechanism  21  together with other components, referred to hereinafter, associated with the components  18 ,  15 ,  16 , while the cutter  11  forms a tape cutting mechanism  22  together with other components, referred to hereinafter, associated with the cutter  11 . The tape feed mechanism  21  and the tape cutting mechanism  22  are driven for operation by an identical drive source (motor) via a torque transmitting mechanism  23  and a clutch mechanism  24  arranged under the cartridge compartment  8  (which will be described in detail hereinafter). Further, the tape exit  10  incorporates a tape strip-holding mechanism  25  for holding a tape strip Ta at the tape exit  10  by pressing the same against a side wall of the tape exit  10  (which will also be described in detail hereinafter). 
     When a label is produced by using the tape printing apparatus  1 , first, the lid  6  is opened, and then the tape cartridge  7  is pushed into the cartridge compartment  8  from above. When the loading of the tape cartridge  7  is completed, the lid  6  is closed to place the tape printing apparatus  1  in a printing wait state. Then, the user enters desired characters and figures by operating the key entry block  4  while watching the liquid crystal display  5 . When the entry of the desired characters and figures is verified on the liquid crystal display  5 , the key entry block  4  is further operated to input a print command. 
     When the print command is issued, the printing tape T and the ink ribbon contained in the tape cartridge  7  start to be rolled out simultaneously, and printing is effected on the printing tape T by the print head  14  in a desired manner. During the printing operation, used part of the ink ribbon is taken up within the tape cartridge  7 , while a printed portion of the printing tape T is sent out of the apparatus  1  via the tape exit  10 . When the printing operation is completed, the printing tape T is further fed by an amount corresponding to a trailing blank space or margin, and then the feed of the printing tape T and the ink ribbon is stopped. Then, the tape cutting mechanism  22  operates to cause the cutter  11  to cut off the printed portion of the printing tape T. The tape strip Ta cut off by the cutter  11  is held at the tape exit  10  such that it can be manually drawn out from the tape exit  10 . 
     Next, the drive system of the apparatus  1  having the tape feed mechanism  21  and the tape cutting mechanism  22  as output ends of the driving system will be described in detail with reference to FIGS. 4 and 5. The drive system includes a motor  31 , a driving block  32  comprised of a gear train linked to a main shaft of the motor  31 , the clutch mechanism  24  linked to the driving block  32 , the torque transmitting mechanism  23  comprised of a feed mechanism-side gear train  33  and a cutting mechanism-side gear train  34  with one of which the clutch mechanism  24  is selectively engaged, the tape feed mechanism  21  linked to the feed mechanism-side gear train  33 , and the tape cutting mechanism  22  linked to the cutting mechanism-side gear train  34 . The motor  31 , the driving block  32 , the clutch mechanism  24 , and the torque transmitting mechanism  23  are mounted on a base frame  26  arranged in a space under the cartridge compartment  8 . 
     The motor  31  is capable of rotating in normal and reverse directions. When the motor  31  performs normal rotation, the torque is transmitted from the driving block  32  to the clutch mechanism  24 , and the clutch mechanism  24  switches to be connected with the feed mechanism-side gear train  33  to further transmit the torque to the feed mechanism-side gear train  33  and the tape feed mechanism  21 . As a result, the platen shaft  15  and the take-up shaft  16  are rotated to feed the printing tape T and the ink ribbon simultaneously. On the other hand, when the motor  31  performs reverse rotation, the torque is transmitted from the driving block  32  to the clutch mechanism  24 , and the clutch mechanism  24  switches to be connected with the cutting mechanism-side gear train  34  to further transmit the torque to the cutting mechanism-side gear train  34  and the tape cutting mechanism  22 . As a result, the cutter  11  is operated to cut the printing tape T. 
     The motor  31  is formed by a DC motor and secured to the base frame  26  in a state slightly tilted with respect to the base frame  26  in view of space efficiency within the apparatus casing  3 . The driving block  32  is comprised of a worm  36  rigidly fitted on the main shaft of the motor  31 , a worm wheel  37  mating with the worm  36 , a thick gear (output gear)  38  having a relatively large thickness and coaxially secured to the underside of the worm wheel  37 , and a rotational shaft  39  on which the worm wheel  37  and the thick gear  38  are rigidly fitted (see FIGS.  6 A and  6 B). The torque of the motor  31  is transmitted via the worm  36  and the worm wheel  37  to the thick gear  38  from which the torque is input to the clutch mechanism  24 . 
     As shown in FIGS. 6A and 6B, the clutch mechanism  24  includes a planet gear  40  mating with the thick gear  38  and a carrier  41  which has an end portion rotatably supporting the planet gear  40  and is loosely fitted on the rotational shaft  39  in a manner movable with rotation of the shaft  39  by frictional drag therewith. When the motor  31  rotates in the normal direction, the worm wheel  37  and the thick gear  38  rotate in unison with the rotational shaft  39 . When the rotational shaft  39  rotates, the carrier  41  is caused to rotate (or swing), by frictional drag, with the rotation of the rotational shaft  39  to cause the planet gear  40  to mate with an input gear  42  of the feed mechanism-side gear train  33 . The torque of the thick gear  38  is transmitted to the planet gear  40  mating therewith, and then to the input gear  42  via the planet gear  40  at a time point the planet gear  40  has mated with the input gear  42 , thereby causing rotation of the input gear  42  (see FIG.  6 A). On the other hand, when the motor  31  performs reverse rotation, the rotational shaft  39  rotates in the reverse direction, whereby the carrier  41  rotates (or swings) to cause the planet gear  40  to mate with an input gear  43  of the cutting mechanism-side gear train  34 . The torque of the thick gear  38  is transmitted to the planet gear  40 , and then to the input gear  43  via the planet gear  40  at a time point the planet gear  40  has mated with the input gear  43 , thereby causing rotation of the input gear  43  (see FIG.  6 B). 
     The feed mechanism-side gear train  33  is comprised of the input gear  42 , a first intermediate gear  45  coaxially secured to the top of the input gear  42 , a second intermediate gear  46  mating with the first intermediate gear  45 , a branching gear  47  coaxially secured to the underside of the second intermediate gear  46 , a take-up gear  48  arranged on a take-up shaft side and mating with the branching gear  47 , a reduction gear  49  arranged on a platen shaft side and also mating with the branching gear  47 , and a platen gear  50  mating with the reduction gear  49 . 
     The torque of the motor  31  input to the input gear  42  is transmitted to the first and second intermediate gears  45 ,  46  and then branched at the branching gear  47  to rotate the take-up gear  48  and the reduction gear  49 . It should be noted that when torque is input to the platen gear  50  e.g. in the case of the printing tape T being drawn out by the user, the input gear  42  pushes the planet gear  40  away to thereby prevent transmission of this torque and at the same time causes rotation of the take-up gear  48  via the branching gear  47  without receiving any load from the motor  31 . As a result, the ink ribbon is taken up by the take-up reel  16  as the printing tape T is drawn out, which prevents the ink ribbon from becoming loose. 
     The cutting mechanism-side gear train  34  is comprised of the input gear  43 , an input bevel gear  52  coaxially secured to the top of the input gear  43 , an output bevel gear  53  mating with the input bevel gear  52 , a long shaft  54  having the output bevel gear  53  rigidly fitted on one end thereof, an intermediate gear  55  rigidly fitted on the other end of the shaft  54 , and a cutter gear  56  mating with the intermediate gear  55 . The torque of the motor  31  input to the input gear  43  is transmitted to the shaft  54  via the two bevel gears  52 ,  53 , and then to the intermediate gear  55  via the shaft  54  to cause rotation of the cutter gear  56 . 
     The tape feed mechanism  21  includes the platen  18  in rolling contact with the printing tape T and the ink ribbon, for feeding them, the platen shaft  15  for rotating the platen  18 , and the take-up shaft  16  for taking up the ink ribbon. The platen  18  is incorporated in the tape cartridge  7  and brought into engagement with the platen shaft  18  when the tape cartridge  7  is loaded in the cartridge compartment  8 . The platen shaft  15  is coaxially and fixedly attached to the platen gear  50  in a cantilever manner. The platen shaft  15  rotates in unison with the platen gear  50  to rotate the platen  18  engaging with the platen shaft  15 . The take-up shaft  16  is coaxially and fixedly attached to the take-up gear  48  in a cantilever manner. The take-up shaft  16  receiving torque from the take-up gear rotates in unison therewith to cause rotation of a reel core of the ink ribbon engaging with the take-up shaft  16 . The take-up shaft  16  is a sliding shaft which causes rotation of the reel core of the ink ribbon by frictional drag while properly sliding thereon to thereby cause the same to take up the ink ribbon. 
     As shown in FIG. 7, the tape cutting mechanism  22  includes the cutter  11  in the form of scissors and a crank disk  58  engaging with the cutter  11  to cause the same to perform a cutting operation. The cutter  11  is comprised of a stationary blade  61  and a movable blade  62 . The two blades  61 ,  62  are coupled to each other by a pivot  63  such that the movable blade  62  can be pivotally moved to perform cutting operations on the stationary blade  61 . The stationary blade  61  is comprised of a blade body  65  and a cutter arm  66  integrally formed with the blade body  65  and extending from the root of the blade body  65  substantially perpendicularly with respect to the same. The stationary blade  61  is attached to the base frame  26  by fixing the cutter arm  66  to the base frame  26 . Attached to the blade body  65  of the stationary blade  61  are an oil absorber  67  containing silicone oil for preventing an adhesive on the printing tape T from adhering to the blade body  65  and a static-eliminating brush  68  for establishing a ground for generated static electricity (see FIG.  4 ). 
     The movable blade  62  is comprised of a blade body  70  and a cutter arm  71  integrally formed with the blade body  70  and extending from the root of the blade body  70  substantially perpendicularly with respect to the same, and the cutter arm  71  is formed with a slot  72  for constant engagement with the crank disk  58 . The crank disk  58  is comprised of a disk body  74  and a crankpin  75  integrally formed on the disk body  74  at a location offset from the center of the same. The cutter gear  56  is coaxially secured to the reverse side of the crank disk  58  (see FIG.  4 ). The crankpin  75  is inserted into the slot  72  of the cutter arm  71  for engagement therewith. That is, the crank disk  58  and the cutter arm  71  form a wobble crank mechanism in which a rotation of the crank disk  58  causes the blade body  70  to perform a cutting operation (reciprocating motion) between a cutting terminal position (forward end position) at which the blade body  70  has slid on the stationary blade  61  and a cutting wait position (rearward end position) at which the blade body  70  is positioned farthest from the stationary blade  61 . 
     It should be noted that, as described in detail hereinafter, a switch end  105   a  of a detection switch  105  is held in sliding contact with the outer peripheral surface of the crank disk  58  which is formed with an arcuate recess  76  for turning on the detection switch  105 . 
     Next, the tape strip-holding mechanism  25  will be described in detail with reference to FIGS. 8 and 9A,  9 B. As shown in FIG. 8, the tape exit  10  formed in the apparatus casing  3  as described hereinbefore is formed by a slit  81  having an open upper end, and an expanding opening  82  spreading outward from the slit  81  in a manner broadening toward the outer end of the tape exit  10 . A portion of the apparatus casing  3  formed with the slit  81  contains the cutter  11  which performs a cutting operation along a cutting line substantially coincident with a center line of the slit  81 . Further, the tape strip-holding mechanism  25  is arranged at a location inward (rightward as viewed in FIGS. 9A and 9B) of a movable blade-side opening wall  83   b  of the apparatus casing  3  forming a wall of the expanding opening  82 , for pressing a cut-off tape strip Ta against a stationary blade-side opening wall  83   a.    
     The tape strip-holding mechanism  25  includes a holding nail  91  for holding a tape strip Ta by pressing the same against the opening wall  83   a , a nail holder  92  in the form of a case, for supporting the holding nail  91  such that it can reciprocate, and a coiled spring  93  for urging the holding nail  91  toward the opening wall  83   a . The holding nail  91  is comprised of a nail  94  slidably extending through a hole formed through the movable blade side opening wall  83   b  and a hole formed through the wall of the nail holder  92 , an engaging projection  95  extending inward from the root of the nail  94 , and a rod  96  extending linearly from the extreme root end of the nail  94  and including a reduced-diameter portion  96   a  slidably extending through a hole formed through the wall of the nail holder  92 , all of which are integrally formed as a unitary member. The holding nail  91  has forward and rearward portions, i.e. the nail  94  and the reduced-diameter portion  96   a  of the rod  96  supported by the nail holder  92  such that the nail  94  can reciprocate between its holding position at which the nail  94  is held in abutment against the stationary blade-side opening wall  83   a  in a state projected from the movable blade-side opening wall  83   b  and its release position at which the nail  94  is in a state retracted toward the inside of the movable blade-side opening wall  83   b.    
     The holding nail  91  has a forward end face formed with a bevel such that it meets the surface of the stationary blade-side opening wall  83   a . More specifically, the forward end face of the holding nail  91  is formed to have a shape complementary to that of the stationary blade-side opening wall  83   a  such that the forward end face can be held in surface contact with the surface of the opening wall  83   a . Fitted on the rod  96  is the coiled spring  93  urging the holding nail  91  in a forward or projecting direction, with one end thereof held in abutment with the root end of the nail  94  and the other end thereof in abutment with an inner wall of the nail holder  92 . The engaging projection  95  of the holding nail  91  urged as above is in contact with the back of the movable blade  62 . Accordingly, the holding nail  91  moves forward and backward according to the cutting operation (pivotal reciprocating motion) of the movable blade  62  to project and retract through the movable blade-side opening wall  83   b . It is preferable that the holding nail  91  reaches its holding position immediately before the movable blade  62  reaches its cutting terminal position. 
     In this preferred case, at the instant (which can be not exactly “the instant”) of the cutter  11  having cut off the printing tape T, the holding nail  91  reaches the stationary blade-side opening wall  83   a  to hold a cut-off tape strip Ta between the surface of the stationary blade-side opening wall  83   a  and itself. This held or sandwiched state of the tape strip Ta is maintained until the next cutting operation starts. Therefore, in the present embodiment, in order to hold the holding nail  91  at its holding position, the cutting operation of the movable blade  61  is stopped when the movable blade  62  reaches its cutting terminal position, and a next cutting operation is started from the cutting terminal position of the movable blade. 
     Now, description will be made, with reference to FIG. 2, of a control system for causing the movable blade  62  to stop at its cutting terminal position. The control system (control means) includes a CPU  101  for centralized control of the motor  31  and the input/output devices, and a detector  102  for detecting a position of the movable blade  62  during a cutting operation. The detector  102  is comprised of an encoder  104  arranged in proximity to the main shaft of the motor  31 , and the detection switch  105  arranged in proximity to the outer peripheral surface of the crank disk  58  of the tape cutting mechanism  22 . The encoder  104  detects a rotational angle of the motor  31 , while the detection switch  105  detects the cutting wait position of the movable blade  62  in cooperation with the recess  76  of the crank disk  58 . 
     Before the start of printing, the movable blade  62  is in the cutting terminal position. In response to a print command, the CPU  101  causes the motor  31  to start reverse rotation. At this time, the torque of the motor  31  is transmitted by the clutch  24  to the cutting mechanism side to cause the rotation of the crank disk  58  whereby the movable blade  62  is pivotally moved toward the cutting wait position. When the switch end  105   a  of the detection switch  105  is let in the recess  76 , the detection switch  105  is turned on to send a detection signal indicative of the sensed cutting wait position of the cutter  11  (movable blade  62 ) to the CPU  101 . In response to the signal, the CPU  101  resets the encoder  104 , and at the same time switches the rotation of the motor  31  from the reverse rotation to the normal rotation. According to this switching of the direction of rotation of the motor  31 , the clutch mechanism  24  operates to cause the torque of the motor  31  to be transmitted to the tape feed mechanism  21  side. As a result, the movable blade  62  is maintained at the cutting wait position, and on the other hand, the printing on the printing tape T is carried out while feeding the printing tape T and the ink ribbon and causing the ink ribbon to be take up. When the printing is completed and further an additional feed of the printing tape T corresponding to a predetermined margin is completed, the CPU  101  switches the rotation of the motor  31  from the normal rotation to the reverse rotation. According to this switching, the clutch mechanism  24  operates to cause the torque of the motor  31  to be transmitted to the cutting mechanism  22  side. This causes the rotation of the crank disk  58  to be resumed, and the cutter in engagement with therewith is operated to cut off the printing tape. Almost simultaneously to this cutting of the printing tape, the encoder  104  detects that the crank disk  58  has rotated through a rotational angle corresponding to a half rotational turn thereof, and delivers a signal indicative of the sensed cutting terminal position of the movable blade  62  to the CPU  101 . In response to this signal, the CPU  101  stops the rotation of the motor  31 , whereby the movable blade is held at the cutting terminal position. That is, the cutting wait position is set as a home position of the cutter  11  (movable blade  62 ), and the movable blade  62  is stopped when it has pivotally moved to the cutting terminal position from the home position. Subsequently, when a print command instructing a next printing operation is received, the CPU  101  causes the reverse rotation of the motor  31  to be resumed, whereby the movable blade  62  is returned to its cutting wait position and held in the wait state. Upon completion of the printing operation, it is again caused to pivotally move to its cutting terminal position. 
     As described above, according to the present embodiment, since the tape feed mechanism  21  and the tape cutting mechanism  22  are both driven by the single motor  31  and by utilizing the normal and reverse rotations of the same, it is possible to reduce the number of motors by one and reduce space conventionally required for installment of two motors by half. This contributes to reduction of the manufacturing costs and size of the apparatus. Further, the use of the clutch mechanism which can be switched automatically by the normal and reverse rotations of the motor  31  makes it possible to dispense with a special mechanism for switching driving forces and hence simplify the construction of the apparatus. 
     It should be noted that a one-way clutch or the like may be used as the clutch mechanism. 
     It is further understood by those skilled in the art that the foregoing are preferred embodiments of the invention, and that various changes and modification may be made without departing from the spirit and scope thereof.