Abstract:
A printing device including a printing mechanism adapted to print a series of letters and characters on a printing tape which is fed through the printing mechanism in a generally vertical orientation. A manually operated cutting mechanism is provided which includes a movable cutting blade configured to cut a printed section of the printing tape at a generally vertical cutting region after a printing operation. The movable cutting blade is rotatably supported in a manner positioning its axis of rotation on one side of the cutting region while the fixed cutting blade is positioned on the other side of the cutting region. The movable cutting blade initially contacts the vertically oriented printing tape from a lower face of the blade during cutting of the printing tape, and moves generally in the direction toward the one side of the cutting region. An operation button provided on a top face of the printing device is configured to move substantially linearly toward a bottom of the printing device. The movable cutting blade rotates toward a fixed cutting blade when the operation button is depressed to manually cut the printing tape disposed between the movable cutting blade and the fixed cutting blade from the lower face of the printing tape.

Description:
This is a Divisional application of prior application Ser. No. 08/969,301, filed Nov. 13, 1997, now U.S. Pat. No. 6,126,344 which is a divisional of Ser. No. 08/611,104, filed on Mar. 5, 1996, now U.S. Pat. No. 5,788,387 which is a divisional of Ser. No. 08/134,213 filed on Oct. 8, 1993, now U.S. Pat. No. 5,595,447. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a tape cartridge for accommodating a long printing tape on which a desirable series of characters are printed, a ribbon cartridge for accommodating an ink ribbon used for printing on the printing tape, and a printing device for detachably receiving the tape cartridge and the ribbon cartridge and printing the desirable series of characters on the printing tape. 
     2. Description of the Related Art 
     A printing tape generally accommodated in a tape cartridge is detachably and replaceably set in a printing device for printing a desirable series of letters and characters on the printing tape. Such a tape cartridge generally includes a mechanism for holding a long tape on a cylindrical tape core and feeding a required amount of the tape out of the tape core so as to efficiently accommodate the long tape and smoothly feed the tape to the printing device. 
     The printing device used with such a tape cartridge has a cutting mechanism for cutting the long tape to be desirable length. The cutting mechanism is typically arranged near a tape outlet to allow the long tape to be cut any desirable position through operation of a lever or the like. 
     An ink ribbon consumed for printing a desirable series of characters on a sheet or tape is also accommodated in an ink ribbon cartridge, which is detachably and replaceably set in the printing device. Such an ink ribbon cartridge generally includes a mechanism for holding a long ink ribbon on a cylindrical ink ribbon core and winding a used ink ribbon on a ribbon winding core so as to compactly accommodate the long ink ribbon and smoothly feed the ink ribbon to the printing device. Both the ink ribbon core and the ribbon winding core are formed to be rotatable via a driving mechanism formed in the printing device for driving and rotating the ink ribbon core and the ribbon winding core. This, the cartridge is not equipped the driving mechanism, effectively reduces the manufacturing cost of each expendable ink ribbon cartridge. 
     Under such a condition that the tape cartridge is not set in a printing device, the tape core unintentionally starts rotation due to some vibration or shock to press an end of the tape into a cartridge case. The end of the tape incidentally entering the cartridge case is not easily removed. 
     Although the cartridge case is to be opened for removal of the tape stuck in the cartridge case, forcible opening of the cartridge case generally accommodating both the tape and the ink ribbon may slacken the ink ribbon or even move the ink ribbon from a predetermined position to damage the whole cartridge. 
     When the tape cartridge having one end of the tape pressed into the cartridge case is accidentally set in a printing device, the tape held and fed between a platen and a printing head is stuck in the tape cartridge to damage the printing device. 
     Another problem arises in the printing device; that is, when the user tries to use a cutting mechanism during printing operation, the tape is not smoothly fed but may be stuck in the printing device. 
     There is also a problem in the ribbon cartridge. The ink ribbon core is rotated through engagement with a driving shaft of a driving element formed in the printing device as mentioned above. The ink ribbon core not being set in the printing device is thus easily rotatable due to vibration or shock so as to slacken the ink ribbon. Slack of the ink ribbon damages an ink ribbon driving mechanism of the printing device or lower the printing quality. 
     A protective sheet or element for interfering with rotation of the ink ribbon core is separately inserted in the ink ribbon core before delivery. Alternatively, a special casing for preventing slack of the ink ribbon is used during delivery and storage of the cartridge. These methods, however, have the following problems. 
     In the former method, manufacturing and management process of the cartridge is rather complicated, and the user should remove the protective sheet before use of the cartridge. When the user sets the cartridge in the printing device without removing the protective sheet, it may cause damage of the ink ribbon driving mechanism of the printing device. 
     In the latter method, for example, one or a plurality of engagement pawls are formed in an inner face of a special case for ribbon cartridge. The engagement pawls engage with the ink ribbon core and interfere with rotation of the ink ribbon core. This requires an additional manufacturing and management process to raise the cost of the expendable cartridge. 
     In such a cartridge, the ink ribbon and the tape are held between the platen and the printing head. When the user forcibly pulls out the tape under non-printing conditions, the ink ribbon joints the tape to be pulled out of the cartridge according to the forcible movement of the tape. 
     SUMMARY OF THE INVENTION 
     One object of the invention is to prevent a tape from being pressed into and stuck in a cartridge case of a tape cartridge, thus making a printing device free from troubles due to the stuck tape. 
     Another object of the invention is to efficiently and securely prevent slack of an ink ribbon due to unintentional rotation of an ink ribbon core in an ink ribbon cartridge. 
     Still another object of the invention is to prevent an ink ribbon from being pulled out of a cartridge according to a forcible movement of a tape. 
     The above and other objects are realized by a tape cartridge including a cartridge case for accommodating a long printing tape freely fed out of the cartridge case for printing in response to operation of a printing device, and a mechanism for preventing an end of the printing tape from being reversely moved back into the cartridge case. 
     The tape cartridge of the invention further includes a tape core on which the long printing tape is wound. The tape core includes, as the reverse movement preventing mechanism, an anti-inversion mechanism for preventing rotation of the tape core in a reverse direction opposite to a feeding direction of the long printing tape for printing. In an alternative structure, the tape core has a flange element with an adhesive inner surface to be in contact with at least one of upper and lower sides of the long printing tape. 
     The anti-inversion mechanism for preventing reverse movement of the printing tape back into the cartridge case includes an engaging element uprightly formed on an outer face of a flange element of the tape core and an engagement element formed on the cartridge case to be located opposite to the engaging element of the tape core. In another structure, the anti-inversion mechanism includes an engagement member mounted on the cartridge case and an engaging element formed on the tape core to be located opposite to the engagement member of the cartridge case. 
     Engagement of the engagement member of the cartridge case with the engaging element of the tape core in the anti-inversion mechanism is released when the tape cartridge is set in the printing device. In a preferable structure, the anti-inversion mechanism allows rotation of the tape core in a normal direction identical with the feeding direction of the long printing tape for printing. 
     In another application of the invention, a tape cartridge includes a cartridge case for accommodating a long printing tape held between a platen and a printing head. The platen is installed in the cartridge case, which has a substantially elliptic aperture for movably receiving a shaft of the platen, and a fixed wall formed in a moving direction of the platen movably fitted in the aperture for holding the printing tape between the platen and the fixed wall. In this structure, a longitudinal axis of the elliptic aperture is located across a feeding direction of the printing tape. When the printing tape is moved to be back into the cartridge case, the platen moves to prevent the printing tape held between the platen and the fixed wall from being moved back into the cartridge case. 
     The cartridge case preferably includes a predetermined length of a guide element arranged near an outlet of the printing tape formed on the cartridge case and along a feeding path of the printing tape. 
     In still another application of the invention, a cartridge includes a cartridge case for accommodating a long printing tape and a long ink ribbon used for printing on the printing tape in a printing device. The cartridge includes a cylindrical ink ribbon core for holding the long ink ribbon thereon and a cylindrical ribbon winding core for holding a used ink ribbon wound thereon after printing in the printing device. The cartridge is detachably set in the printing device. The ink ribbon core has an engaging element on a portion exposed under such a condition that the ink ribbon is wound on the ink ribbon core. The cartridge case rotatably supporting the ink ribbon core has an engagement piece to engage with the engaging element of the ink ribbon core to prevent rotation of the ink ribbon core. 
     A printing device according to the invention includes a cartridge holder unit for detachably receiving a cartridge with a printing tape accommodated therein. The printing tape accommodated in the cartridge is fed with an ink ribbon for printing. The printing device further includes a platen driving shaft engaging with a platen mounted on the cartridge and rotating the platen to feed the printing tape according to rotation of the platen driving shaft, a cutting mechanism for cutting the printing tape fed out of the cartridge according to the rotation of the platen driving shaft at a desirable position, a detection unit for detecting a movement of the cutting mechanism during the rotation of the platen driving shaft, and a stop mechanism for interrupting the rotation of the platen driving shaft when the movement of the cutting mechanism is detected by the detection unit. 
     In another application, a printing device includes a cartridge holder unit for detachably receiving a cartridge accommodating a printing tape and an ink ribbon core with an ink ribbon wound thereon and fed out of the cartridge for printing. The ink ribbon core has an engaging element formed on a portion exposed under such a condition that the ink ribbon is wound on the ink ribbon core. The cartridge has an engagement piece to engage with the engaging element of the ink ribbon core. The cartridge holder unit of the printing device includes an upright contact projection for being in contact with the engagement piece formed in the cartridge to move the engagement piece in a release direction for releasing the engagement of the engagement piece with the engaging element of the ink ribbon core when the cartridge is mounted on the cartridge holder unit. 
     In still another application of the invention, a printing device includes a cartridge holder unit for detachably receiving a cartridge accommodating a printing tape and a ribbon winding core with a used ink ribbon wound thereon after printing. The ribbon winding core has a second engaging element formed on a portion exposed under such a condition that the used ink ribbon is wound on the ribbon winding core. The cartridge has a second engagement piece to engage with the second engaging element of the ribbon winding core. The cartridge holder unit of the printing device includes a second upright contact projection for being in contact with the second engagement piece formed in the cartridge to move the second engagement piece in a release direction for releasing the engagement of the second engagement piece with the second engaging element of the ribbon winding core when the cartridge is mounted on the cartridge holder unit. 
     In another preferable structure of the invention, a printing device includes a cartridge holder unit for detachably receiving a cartridge accommodating a cylindrical ink ribbon core with a long ink ribbon wound thereon, a cylindrical ribbon winding core with the long ink ribbon wound thereon after being used for printing in the printing device, and a long printing tape on which a desirable series of characters are printed by an ink of the ink ribbon. The printing device further includes a printing head for adhesively holding the printing tape and the ink ribbon between a platen and the printing head, a driving unit for feeding the printing tape and rotating the ribbon winding core synchronously with the feed of the printing tape, and a ribbon winding core driving unit for rotating the ribbon winding core according to a pull-out movement of the printing tape under non-printing conditions. 
     The driving unit of the printing device preferably includes a stepping motor functioning as a driving source, a first transmission mechanism for transmitting rotation of the stepping motor to the platen, and a second transmission mechanism diversified at a predetermined point from the first transmission mechanism for transmitting the rotation of the stepping motor to the ribbon winding core. The ribbon winding core driving unit preferably includes a one-way clutch arranged between the stepping motor and the predetermined point of the first transmission mechanism for interfering with transmission of rotation from the platen. 
     These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view illustrating a tape printing device  1  as a first embodiment according to the invention; 
     FIG. 2 is a right side view showing the tape printing device  1  of FIG. 1; 
     FIG. 3 is a plan view showing assembly of a tape cartridge  10  in the first embodiment; 
     FIG. 4 is a bottom view showing the tape cartridge  10  of FIG. 3; 
     FIG. 5 is an end view illustrating the tape cartridge taken on the line V—V of FIG. 3; 
     FIG. 6 is an end view showing an internal structure of the tape cartridge  10  with a 6 mm wide tape; 
     FIG. 7 is an end view showing an internal structure of the tape cartridge  10  with a 24 mm wide tape; 
     FIG. 8 shows a relationship between the width of a tape T accommodated in the tape cartridge  10  and the depth of three detection holes  18 K; 
     FIG. 9 is an end view illustrating the tape printing device  1  taken on the line IX—IX of FIG. 1; 
     FIG. 10 is a plan view showing a typical structure of a tape cartridge holder unit  50 A; 
     FIG. 11 is a perspective view illustrating a gear train and a mechanism for shifting a printing head  60  between a retreated position and a printing position; 
     FIG. 12 is an end view showing the mechanism for shifting the printing head  60  taken on the line XII—XII of FIG. 10; 
     FIG. 13 is an end view showing a cutting mechanism taken on the line XIII—XIII of FIG. 10; 
     FIG. 14 is a block diagram showing an circuitry structure of tape printing device  1 ; 
     FIG. 15 shows a typical example of a key arrangement on an input unit  50 C; 
     FIG. 16 shows a structure of a display unit  50 D; 
     FIG. 17 is a perspective view illustrating another mechanism of preventing rotations of the tape core  20 ; 
     FIG. 18 is a cross sectional view showing a cartridge  210  of a second embodiment according to the invention; 
     FIG. 19 is a cross sectional view illustrating the cartridge  210  set in the tape writer  1 ; 
     FIG. 20 is a decomposed perspective view of the cartridge  210 ; 
     FIG. 21 is a perspective view illustrating an essential part of a tape core  202  in the second embodiment; 
     FIG. 22 schematically shows a clutch mechanism having a plurality of wedge-shaped grooves in another tape cartridge; 
     FIG. 23 shows still another tape cartridge having a coil spring; and 
     FIG. 24 shows another tape cartridge having a clutch pawl. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Structures and functions of the present invention will become more apparent through description of the following preferred embodiments of the invention. 
     FIG. 1 is a plan view illustrating a tape printing device  1  embodying the invention, and FIG. 2 is a right side view of the tape printing device  1 . In the description below, the relative position of each constituent, for example, right, left, upper, or lower, corresponds to the drawing of FIG.  1 . 
     As shown in FIGS. 1 and 2, the tape printing device  1  includes a casing  50 H for accommodating a variety of constituents, an input unit  50 C having sixty-three keys, a freely openable cover  50 K, a display unit  50 D arranged visibly through a window  50 M of the cover  50 K for displaying a series of characters or other required information, and a tape cartridge holder unit  50 A (see FIG. 10) disposed on a left upper portion of the device  1 , which a tape cartridge  10  is detachably attached to. A window for checking attachment of the tape cartridge  10  is provided on the cover  50 K. Both windows  50 L and  50 M are covered with transparent plastic plates. 
     Operation of the tape printing device  1  thus constructed is described briefly. In a first step, an operator opens the cover  50 K and attaches the tape cartridge  10  to the tape cartridge holder unit  50 A. After closing the cover  50 K, the operator turns on a power switch  50 J externally mounted on a right side wall of a main body of the device  1  as shown in FIG.  2 . The device  1  subsequently executes an initial processing to ready for an input of letters or characters. The operator then inputs a desirable series of letters or characters with the keys on the input unit  50 C. Although input of letters is implemented directly through key operation of the input unit  50 C, an additional process such as conversion from the input letters into Chinese characters may be required in certain linguistic areas using two-bite characters like Chinese characters. When the operator instructs printing through a key operation, the device  1  drives a thermal transfer printer unit  50 B to start printing on a tape T fed from the tape cartridge  10 . The tape T with the letters or characters printed thereon is fed out of a tape outlet  10 A disposed on a left side wall of the tape printing device  1 . 
     The tape T used in the embodiment has a printing surface specifically processed for preferable ink spread by thermal transfer and an adhesive rear face which a peel tape is applied on. After the printed tape T is cut by a desirable length to a label with a built-in blade cutter and the peel tape is peeled off, the label with characters and symbols printed thereon is applied onto any desirable place. 
     Structure and functions of the tape cartridge  10  are described mainly based on the plan view of FIG. 3, the bottom view of FIG. 4, and the cross sectional view of FIG. 5 taken on the line V—V of FIG.  3 . Each tape cartridge  10  having a similar structure can hold a tape of a predetermined width. Five types of tape cartridges for tapes of 6 mm, 9 mm, 12 mm, 18 mm, and 24 mm in width are prepared in the embodiment. FIG. 6 is a partly broken cross sectional view showing an internal structure of the tape cartridge  10 , which includes a 6 mm wide tape T running through centers of an ink ribbon core  22 , a ribbon winding core  24 , and a platen  12 . FIG. 7 is also a cross sectional view showing the same with a 24 mm wide tape T. Numbers or symbols representing respective constituents are omitted in FIG. 7 for clarity of the drawing. In FIGS. 6 and 7, part of a printing head  60  is drawn together with the cross section of the tape cartridge  10  to show attachment of the tape T in the tape printing device  1 . 
     The platen  12  is a hollow cylindrical member covered with a platen rubber  14  of a predetermined width corresponding to the width of the tape T. The platen rubber  14  improves contact of the tape T to an ink ribbon R and the printing head  60  for desirable printing. In the embodiment, two types of the platen rubber  14  are used; a 12 mm wide platen rubber for 6 mm, 9 mm, and 12 mm tapes (see FIG.  6 ), and a 18 mm wide platen rubber for 18 mm and 24 mm tapes (see FIG.  7 ). 
     The platen  12  has a smaller-diametral upper end and a smaller-diametral lower end. The platen  12  is freely rotatable since the smaller-diametral upper end and the smaller-diametral lower end are rotatably fit in apertures  16 A and  18 A of a top wall  16  and a bottom wall  18  of the tape cartridge  10 , respectively. The apertures  16 A and  18 A are formed in substantially elliptic shape as seen in FIG.  4 . The hollow platen  12  accommodated in the tape cartridge  10  is attached to and detached from a platen driving shaft (described later) disposed in the tape printing device  1  according to attachment and detachment of the tape cartridge  10 . The platen  12  has six engagement grooves  12 A arranged at the equal intervals on an inner surface thereof along a rotational axis of the platen  12  as shown in FIGS. 4 and 6. The engagement grooves  12 A engage with the platen driving shaft to transmit a driving force of the driving shaft. 
     The tape cartridge  10  is also provided with a tape core  20  which a long tape T is wound on, the ink ribbon core  22 , and the ribbon winding core  24 . The tape cartridge  10  further includes a printing head receiving hole  32  which the printing head  60  enters and goes in. The printing head receiving hole  32  is defined by a guide wall  34 . 
     The tape core  20  is a hollow, large-diametral cylindrical reel for placing a long tape T wound on a relatively large-diametral bobbin in the tape cartridge  10 . Since a total thickness of the wound tape T on the tape core  20  is small as compared with the diametral of the tape core  20 , a rotational angular velocity of the tape core  20  for pulling an outer-most wind of the tape T (shown as α in FIG. 3) out of the tape core  20  at a certain rate is approximately same as a rotational angular velocity of the tape core  20  for pulling an inner-most wind of the tape (shown as β in FIG. 3) at the same rate. A sufficiently large radius of curvature of tape core  20  allows even a tape T having poor resistance to a bending stress to be wound on the tape core  20  without difficulty. 
     As shown in FIG. 3, the tape core  20  has a shaft hole  20 B on a center thereof, which rotatably receives a shaft member  18 B uprightly projecting from the bottom wall  18  of the tape cartridge  10  as clearly seen in FIG.  5 . The tape core  20  is provided with a pair of circular thin films  20 A respectively applied on axial upper and lower ends of the tape core  20 . The thin film  20 A has an adhesive layer. Since the film  20 A functioning as a flange with respect to the tape T has the adhesive layer facing the tape T, side edges of the tape T lightly adhere to the film  20 A. This keeps the roll of the tape T wound when rotation of the platen  12  pulls the tape T out and makes the tape core  20  drivingly rotate. 
     As shown in FIG. 3, the tape T wound and accommodated in the tape core  20  runs to the platen  12  via a tape guide pin  26  uprightly projecting from the bottom wall  18  of the tape cartridge  10  and goes out of the tape outlet  10 A of the tape cartridge  10 . The tape outlet  10 A has a guide element  10 B of a predetermined length formed along a feeding direction of the tape T. While the tape cartridge  10  is set in the tape cartridge holder unit  50 A, the printing head  60  is placed in the printing head receiving hole  32 . Under such conditions, the tape T is held between the printing head  60  and the platen  12  and fed according to rotation of the platen  12 . 
     The apertures  16 A and  18 A receiving the upper and lower ends of the platen  12  are formed in elliptic shape as mentioned above, and the platen  12  is movable along longitudinal axes of the apertures  16 A and  18 A when the tape cartridge  10  is not set in the tape printing device  1 . When the tape T outside the tape cartridge  10  is being pressed into the tape cartridge  10 , the platen  12  moves along a feeding direction of the tape T. Movement of the platen  12  causes the platen rubber  14  on the platen  12  to be in contact with a circumference of the tape guide pin  26  and securely holds the tape T between the platen rubber  14  and the tape guide pin  26 . This interferes with further movement of the tape T. Such a structure effectively prevents from the tape T being mistakenly pressed into the tape cartridge  10 . 
     Winding procedure of the ink ribbon R is now described. The ink ribbon core  22  includes a hollow, small-diametral cylindrical member having smaller-diametral upper and lower ends as clearly seen in FIGS. 6 and 7. The smaller-diametral lower end has six engagement grooves formed as first engaging elements  22 A arranged at the equal intervals as shown in FIGS. 3 and 4. The smaller-diametral lower end of the ink ribbon core  22  is loosely fitted in a circular first fitting aperture  18 C formed on the bottom wall  18  of the tape cartridge  10 . The upper hollow end of the ink ribbon core  22  is loosely fitted in a cylindrical guide projection  16 C protruded from the top wall  16  of the tape cartridge  10 . The ink ribbon core  22  is accordingly held to be drivingly rotatable according to pull-out of the ink ribbon R. 
     As shown in FIGS. 3 and 4, a substantially L-shaped first engagement piece  18 D is formed on the bottom wall  18  of the tape cartridge  10  to be positioned in the vicinity of the lower ends of the ink ribbon core  22  and the ribbon winding core  24  (described later). The first engagement piece  18 D is formed by cutting part of the bottom wall  18  of the tape cartridge  10  (hatched portion designated as X in FIG.  3 ). Resilience of the material of the bottom wall  18  allows a free end of the first engagement piece  18 D to be movable around a base portion  18 E integrally formed with the bottom wall  18  along the plane of the bottom wall  18 . When no force is applied onto the first engagement piece  18 D, the free end of the first engagement piece  18 D is positioned inside the circumference of the first fitting aperture  18 C and engages with one of the six engaging elements  22 A formed on the lower end of the ink ribbon core  22  loosely fitted in the fitting aperture  18 C. This effectively prevents the ink ribbon core  22  from being unintentionally rotated and the ink ribbon R from being slack. 
     The ink ribbon R wound and accommodated in the ink ribbon core  22  is pulled out via a ribbon guide roller  30  and runs along the guide wall  34  to the ribbon winding core  24 . In the middle of the ribbon path, the ink ribbon R reaches a position facing the platen  12  to be overlapped with the tape T. In FIG. 3, γ and δ respectively show the running conditions of the ink ribbon R when the tape cartridge  10  is still unused and new, that is, when only a starting end of the ink ribbon R is on the ribbon winding core  24 , and when the whole ink ribbon R is wound on the ribbon winding core  24 . 
     The ribbon winding core  24  includes a hollow cylindrical member of substantially the same shape as the ink ribbon core  22  as shown in FIGS. 3 and 4. The hollow cylindrical member has smaller-diametral upper and lower ends in the same manner as the ink ribbon core  22 . The lower end has six engagement grooves formed as second engaging elements  24 A arranged at the equal intervals. As is the platen  12 , the ribbon winding core  24  rotates through engagement with a ribbon winding core driving shaft (described later) disposed in the tape printing device  1 . The ribbon winding core  24  thus has six engagement grooves  24 B arranged at the equal intervals on an inner surface of the hollow cylindrical member along a rotational axis of the ribbon winding core  24 . The smaller-diametral upper and lower ends of the ribbon winding core  24  are loosely and rotatable fitted in a top circular fitting aperture  16 G and a bottom circular fitting aperture  18 G formed on the top wall  16  and the bottom wall  18  of the tape cartridge  10 , respectively. 
     In the same manner as the ink ribbon core  22 , a substantially L-shaped second engagement piece  18 H is formed on the bottom wall  18  of the tape cartridge  10  to prevent unintentional rotation of the ribbon winding core  24 . The second engagement piece  18 H is formed by cutting part of the bottom wall  18  of the tape cartridge  10  (hatched portion designated as Y in FIG.  3 ). When the tape cartridge  10  is not set in the tape printing device  1 , a free end of the second engagement piece  18 H is positioned inside the circumference of the bottom fitting aperture  18 G and engages with one of the six second engaging elements  24 A formed on the lower end of the ribbon winding core  24 . The ribbon winding core  24  is thereby not rotated in such a direction as to slacken the ink ribbon R wound thereon. The free ends of the first engagement piece  18 D and the second engagement piece  18 H are respectively positioned not to be perpendicular but to be inclined to the first and second engaging elements  22 A and  24 A. This prevents the ink ribbon core  22  and the ribbon winding core  24  from rotating in undesirable directions as described above. The ribbon winding core  24  readily rotates in a normal winding direction of the ink ribbon R. 
     Engagement of the first engaging element  22 A of the ink ribbon core  22  with the first engagement piece  18 D and that of the second engaging element  24 A of the ribbon winding core  24  with the second engagement piece  18 H effectively prevent the ink ribbon R from undesirably slackening while the tape cartridge  10  is not set in the tape printing device  1 . The engagement is released when the tape cartridge  10  is set in the tape cartridge holder unit  50 A. The releasing procedure is described later with a typical structure of the tape cartridge holder unit  50 A. 
     The ink ribbon R wound on the ribbon winding core  24  is a thermal transfer ribbon having a predetermined width corresponding to the width of the tape T used for printing. In the embodiment, a 12 mm wide ink ribbon R is used for 6 mm, 9 mm, and 12 mm wide tapes T as shown in FIG. 6, a 18 mm wide ink ribbon R for a 18 mm wide tape T (not shown), and a 24 mm wide ink ribbon R for a 24 mm wide tape T as shown in FIG.  7 . 
     When the width of the ink ribbon R is equal to the height of the tape cartridge  10  (see FIG.  7 ), the top wall  16  and the bottom wall  18  of the tape cartridge  10  guide the ink ribbon R. No additional flange is thus required on the circumference of the ribbon winding core  24  for controlling and adjusting a winding position of the ink ribbon R. When the width of the ink ribbon R is smaller than the height of the tape cartridge  10 , on the other hand, a flange  24 C is formed on the circumference of the ribbon winding core  24  to guide the ink ribbon R to go through a printing position of the platen  12 . The flange  24 C is formed in a certain size corresponding to the width of the ink ribbon R. 
     In the embodiment, there are tape cartridges  10  of five different sizes corresponding to the width of the tape T as described above. Since a printable area of the tape T differs according to the width of the tape T, a variety of condition setting procedures are required. The tape printing device  1  detects the size of the tape cartridge  10  and automatically executes required setting, thus making the user free from troublesome setting. The tape cartridge  10  of the embodiment has first through third detection holes  18 Ka,  18 Kb, and  18 Kc formed on the bottom wall  18  corresponding to the size of the tape T as shown in FIG.  4 . Namely, depths of the three detection holes  18 Ka,  18 Kb, and  18 Kc are changed according to the width of the tape T accommodated in the tape cartridge  10 . 
     FIG. 8 shows a relationship between the width of the tape T accommodated in the tape cartridge  10  and the depths of the three detection holes  18 Ka,  18 Kb, and  18 Kc. As shown in FIG. 8, the first detection hole  18 Ka is formed shallow and the second and third detection holes  18 Kb,  18 Kc of the tape cartridge  10  are formed deep for a 6 mm wide tape. The first and third detection holes  18 Ka,  18 Kc are formed deep for a 9 mm wide tape; only the third detection hole  18 Kc is deep for a 12 mm wide tape; and the first and second detection holes  18 Ka,  18 Kb are deep for a 18 mm wide tape. Only second detection hole  18 kb is formed deep for a 24 mm wide tape. Since the size of the tape cartridge  10  is designated as a combination of the depths of the three detection holes  18 Ka through  18 Kc, the user can also check the tape cartridge  10  with eyes. 
     The tape cartridge  10  thus constructed is set in the tape cartridge holder unit  50 A of the tape printing device  1 . The tape printing device  1  includes an extension unit  50 E for connecting various packs optionally supplied as external memory elements, the input unit  50 C, and a control circuit unit  50 F for controlling the display unit  50 D and the printer unit  50 B as shown in the cross sectional view of FIG. 9 taken on the line IX—IX of FIG.  1 . 
     The tape printing device  1  is also provided on a bottom face thereof with a battery holder unit  50 I for receiving six SUM- 3  cells working as a power source of the whole device  1 . The power switch  50 J is mounted on the right side wall of the tape printing device  1  (see FIG.  2 ). Power may be supplied from a plug  50 N (see FIG. 2) formed on the right side wall of the device  1  to be connectable with an AC adapter (not shown). 
     Mechanical constituents of the tape printing device  1  are described hereinafter. FIG. 10 is a plan view showing a typical structure of the tape cartridge holder unit  50 A, and FIG. 11 is a perspective view illustrating an essential structure of a driving mechanism  50 P for driving the platen  12  and the other elements by means of power of a stepping motor  80 . 
     The tape cartridge holder unit  50 A is disposed in a left upper position of a main body of the tape printing device  1  and defines an attachment space corresponding to the shape of the tape cartridge  10  as shown in FIG.  10 . The platen driving shaft and the ribbon winding core driving shaft respectively engaging with the hollow members of the platen  12  and the ribbon winding core  24  as well as the printing head  60  are uprightly disposed in the attachment space of the tape cartridge holder unit  50 A as shown in FIG.  11 . The tape cartridge holder unit  50 A is also provided on a lower portion thereof with the driving mechanism  50 P for transmitting rotation of the stepping motor  80  to the platen  12  and other elements. The driving mechanism  50 P disposed below the tape cartridge holder unit  50 A is not observable even when the cover  50 k is open. FIG. 11 shows the driving mechanism  50 P when the inner case of the tape cartridge holder unit  50 A is eliminated. The attachment space of the tape cartridge holder unit  50 A is covered with the cover  50 K while the tape printing device  1  is in service. 
     The tape cartridge  10  is attached to or replaced in the tape cartridge holder unit  50 A while the cover  50 K is open. When a slide button  51  (see FIGS. 1 and 10) disposed before the tape cartridge holder unit  50 A is slid rightward (in the drawing), engagement of the cover  50 K with the main body of the device  1  is released, so that the cover  50 K rotates around a cover hinge  54  mounted on a rear portion of the main body of the device  1  to be opened. A spring arm  52 A integrally formed with the slide button  52  engages with an engaging element of the main body of the device  1  to continuously apply a leftward (in the drawing) pressing force to the slide button  52 . 
     When the cover  50 K is opened through operation of the slide button  52 , the printing head  60  for printing the tape T of the tape cartridge  10  is retreated to allow the tape cartridge  10  to be attached or detached. The printing head  60  is rotatably mounted on a head rotating shaft  64  projected from a base board  61  as clearly seen in FIG.  11 . The printing head  60  includes a head body  65  having a plurality of heating dot elements, a radiator plate  65   b  holding the head body  65  via an insulator  65   a,  a frame element  67  for supporting the radiator plate  65   b  through a connection plate  67   a,  a coil spring  66  pressing the printing head  60  in an initial direction, and a flexible cable constituting an electric wiring to the head body  65 . 
     The printing head  60  is only roughly aligned with the platen  12  in the tape cartridge  10  through attachment of the tape cartridge  10  in the tape printing device  1 . Namely, the printing head  60  is not always in contact with the platen rubber  14  along the height of the platen  12  uniformly when the tape cartridge  10  is set in the device  1 . In the tape printing device  1  of the embodiment, the connection plate  67   a  is fixed to the frame element  67  via a pin  67   b  inserted into an opening of the connection plate  67   a,  and the radiator plate  65   b  holding the head body  65  is thus rotatable around the pin  67   b.  This allows the head body  65  to hold the tape T between the platen  12  and the head body  65  and to be uniformly in contact with the height of the platen  12  irrespective of the attachment conditions of the tape cartridge  10  with respect to the tape cartridge holder unit  50 A when the printing head  60  is pressed towards the platen  12 . 
     A lower end of the frame element  67  is extended to form a link plate  62 . The link plate  62  is positioned in a gear train shown in FIG. 11, and has a free end positioned in the vicinity of a boundary of the display unit  50 D (see FIG.  10 ). The free end of the link plate  62  holds one end of a coil spring  69  to connect a driving member  63  with the link plate  62 . The driving member  63  having a substantially triangular shape has a first end  63   a  holding the other end of the coil spring  69  and a second end  63   b  placed opposite to the cover  50 K as shown in FIG.  11 . An operation arm  50 S is extended from the cover  50 K to be positioned opposite to the second end  63   b  of the driving member  63 , and presses the second end  63   b  when the cover  50 K is closed. 
     FIG. 12 is a cross sectional view schematically showing such a movement described above, taken on the line XII—XII of FIG.  10 . When the cover  50 K is pressed downward, the operation arm  50 S presses the second end  63   b  of the driving member  63  downward, and the link plate  62  rotatingly moves rightward (in FIG. 11) via the coil spring  69 , accordingly. Such a rotating movement of the link plate  62  rotates the printing head  60  against the pressing force of the coil spring  66 . The printing head  60  thereby moves from its retreated position to a printing position facing the platen  12  of the tape cartridge  10  set in the tape printing device  1 . When the cover  50 K is closed, the printing head  60  is accordingly shifted to the printing position. When the cover  50 K is opened, on the contrary, the printing head  60  is shifted to the retreated position to allow the tape cartridge  10  to be detached or attached. The printing head  60  once retreated is kept in the retreated position by means of the coil spring  66  while the cover  50 K is open, and goes back to the printing position to press against the platen  12  when the cover  50 K is closed. 
     As described previously, the first engagement piece  18 D and the second engagement piece  18 H are formed on the bottom wall  18  of the tape cartridge  10  to engage with the first engaging element  22 A and the second engaging element  24 A so as to prevent unintentional rotation of the ink ribbon core  22  and the ribbon winding core  24  (see FIGS.  3  and  4 ). The first engagement piece  18 D and the second engagement piece  18 H are formed respectively by cutting the parts of the bottom wall  18  (hatched portions designated as X and Y in FIG.  3 ). The tape cartridge holder unit  50 A has two cone-shaped contact projections  70 A and  70 B at a position substantially in the middle of the hatched portions X and Y as shown in FIG.  10 . When the tape cartridge  10  is set in the tape cartridge holder unit  50 A, the contact projections  70 A and  70 B are fitted in the hatched portions X and Y of the bottom wall  18  of the tape cartridge  10  to press the first and the second engagement pieces  18 D and  18 H in a direction away from the first engaging element  22 A of the ink ribbon core  22  and the second engaging element  24 A of the ribbon winding core  24 . This pressing movement releases engagement of the first and the second engagement pieces  18 D and  18 H with the ink ribbon core  22  and the ribbon winding core  24 , thus allowing the ink ribbon core  22  and the ribbon winding core  24  to rotate without any additional load. 
     A transmission mechanism for transmitting rotation of the stepping motor  80  to a platen driving shaft  72  of the platen  12  is described in detail. As shown in FIG. 11, a first gear  81  is attached to a rotational shaft  80 A of the stepping motor  80 , and a clutch arm  80 B engages with the rotational shaft  80 A with predetermined friction. The clutch arm  80 B, together with a second gear  82  and a third gear  83 , constitutes a one-way clutch. When the stepping motor  80  is rotated in a direction shown by the arrow C in FIG. 11, the friction between the rotational shaft  80 A and the clutch arm  80 B rotates the clutch arm  80 B with the second gear  82  in the directions shown by the arrow C to engage with the third gear  83 . Rotation of the stepping motor  80  is thus transmitted to the third gear  83 . Functions of the one-way clutch will be further described later. 
     Rotation of the third gear  83  is then transmitted to a fifth gear  85  and a sixth gear  86  via a fourth gear  84  through repeated gear-down operation. A rotational shaft of the fifth gear  85  is connected to a ribbon winding core driving shaft  74  to wind the ink ribbon R according to rotation of the stepping motor  80 . A rim  74 A actually driving the ribbon winding core  24  is attached to the ribbon winding core driving shaft  74  with a predetermined friction. Under normal operating conditions, the rim  74 A rotates with the ribbon winding core driving shaft  74  rotated by the stepping motor  80 . When the ribbon winding core  24  is made unrotatable, for example, due to completion of winding of the ink ribbon R, on the other hand, the rim  74 A slips against rotation of the ribbon winding core driving shaft  74 . 
     Rotation of the sixth gear  86  is further transmitted to a seventh gear  87  to rotate the platen driving shaft  72 . The platen driving shaft  72  has a rim  72 A which engages with the inner surface of the platen  12  to rotate the platen  12 . Rotation of the stepping motor  80  transmitted to the third gear  83  by means of the one-way clutch finally rotates the platen driving shaft  72  and the ribbon winding core driving shaft  74 , accordingly. The tape T held between the platen rubber  14  on the circumference of the platen  12  and the head body  65  of the printing head  60  is thus continuously fed with progress of printing, and the ink ribbon R is wound on the ribbon winding core  24  synchronously with feeding of the tape T. 
     The platen driving shaft  72  has, on an outer surface thereof, three engagement projections  72 B which are formed at the equal intervals to engage with the engagement grooves  12 A formed on the inner surface of the platen  12 . The ribbon winding core driving shaft  74  also has three engagement projections  74 B which are formed at the equal intervals on an outer surface thereof to engage with the engagement grooves  24 B formed on the inner surface of the ribbon winding core  24 . When the platen driving shaft  72  and the ribbon winding core driving shaft  74  are rotated at a predetermined rate by the stepping motor  80 , the tape T and the ink ribbon R are respectively pulled by a predetermined amount out of the tape core  20  and the ink ribbon core  22  to be overlapped with each other and go through the platen rubber  14  and the printing head  60 . In the meanwhile, power supplied to the printing head  60  controls heating of the dot elements on the printing head  60  to melt ink of the ink ribbon R corresponding to the heated dot elements. The melted ink is then thermally transferred to the tape T to complete printing on the tape T. After printing, the tape T with the print is fed out from the tape cartridge  10  while the ink ribbon R used for printing is wound on the ribbon winding core  24 . 
     The tape T conveyed with progress of printing is finally fed out of the tape outlet  10 A disposed on the left side wall of the main body of the tape printing device  1 . The tape T with the print is normally cut with a cutting mechanism (described later). There is, however, a possibility that the user forcibly pulls out the tape T prior to cutting. Since the printing head  60  presses the tape T against the platen rubber  14  of the platen  12  while the cover  50 K is closed, the forcible pull-out of the tape T makes the platen driving shaft  72  rotate. The gear-down operation and a certain amount of retaining torque of the stepping motor  80 , however, prevent rotation of the platen driving shaft  72  and the ribbon winding core driving shaft  74  in a conventional driving mechanism. The forcible pull-out of the tape leads to unintentional pull-out of the ink ribbon R, accordingly. When the tape T is cut with the cutting mechanism under such circumstances, the ink ribbon R is also cut undesirably. This makes the tape cartridge  10  unusable any more. 
     In the embodiment, the one-way clutch including the clutch arm  80 B, the second gear  82 , and the third gear  83  solves such a problem. When the user forcibly pulls out the tape T, the platen driving shaft  72  rotates with the platen  12  in the structure of the embodiment. Rotation of the platen driving shaft  72  is transmitted to the third gear  83  via the gear train to rotate the third gear  83  clockwise. Rotation of the third gear  83  makes the second gear  82  rotate. However, since the rotational shaft  80 A of the stepping motor  80  is not rotated, a rotational force of the third gear  83  presses the clutch arm  80 B supporting the second gear  82  to release engagement of the third gear  83  with the second gear  82 . This results in separating the third through seventh gears  83  through  87  from the stepping motor  80  to allow the ribbon winding core driving shaft  74  to rotate with rotation of the platen driving shaft  72  due to pull-out movement of the tape T. The rotation of the ribbon winding core driving shaft  74  makes the ink ribbon R wound on the ribbon winding core  24  with pull-out of the tape T, thus effectively preventing unintentional pull-out of the ink ribbon R with the tape T. When the stepping motor  80  starts rotating, the clutch arm  80 B is shifted again towards the third gear  83  to engage the second gear  82  with the third gear  83 . Since a free end of the clutch arm  80 B is fitted in an opening  80 C formed on a base  61  as shown in FIG. 11, the movement of the clutch arm  80 B is defined in a relatively small range. This moving range is, however, sufficient to make the clutch arm  80 B function as the one-way clutch. 
     The tape T with the print fed leftward out of the tape cartridge  10  is readily cut with the cutting mechanism, which is shown in detail in FIGS. 10 and 13. FIG. 13 is a cross sectional view mainly showing the cutting mechanism, taken on the line XIII—XIII of FIG. 10. A cutter support shaft  92  protruded from a bottom face of the tape cartridge holder unit  50 A holds a substantially L-shaped, pivotably movable tape cutter  90  and a spring  94 . A resilient force of the spring  94  keeps the tape cutter  90  under such a condition that a clockwise rotational force is applied onto the tape cutter  90  as shown by the solid line in FIG.  13 . With this clockwise rotational force, a left end  90 A of the tape cutter  90  presses a cutter button  96  upward. The left end  90 A of the tape cutter  90  is formed in a fork shape to receive a pin  96 A mounted on a rear face of the cutter button  96 . When the cutter button  96  is pressed downward, the left end  90 A of the tape cutter  90  shifts downward, accordingly. 
     A right end  90 B of the tape cutter  90  has a movable blade  98  for cutting the tape T, which is arranged at a predetermined angle apart from a fixed blade  91  attached to a side face of the tape cartridge holder unit  50 A. A shoulder  93 A of a tape support finger  93  (see FIG. 10) is in contact with a rear face of the right end  90 B of the tape cutter  90 . The tape support finger  93  is pressed against a feeding path of the tape T by a spring  95  as shown in FIG.  10 . When the tape cutter  90  rotates to shift the movable blade  98  towards the fixed blade  91 , the tape support finger  93  moves towards the feeding path of the tape T. A fixed wall  97  is disposed opposite to the tape support finger  93  across the feeding path of the tape T. The tape T is fixed between the tape support finger  93  and the fixed wall  97  prior to cutting of the tape T by the movable blade  98  and the fixed blade  91 . Movement of the tape support finger  93  is detected by a detection switch  99 , which prevents printing during the cutting operation of the tape T as described later. 
     The tape T is cut by pressing the cutter button  96  downward against the resilient force of the spring  94 . When the cutter button  96  is pressed downward to rotate the tape cutter  90  counterclockwise (in FIG.  13 ), the movable blade  98  formed on the right end  90 B of the tape cutter  90  also rotates counterclockwise. The tape support finger  93  and the fixed wall  97  securely hold the tape T therebetween, and the movable blade  98  is gradually overlapped with the fixed blade  91  to cut the tape T. Accordingly, as shown in FIGS. 13 and 18, the downward mounting direction of the printing cartridge  201  into the cartridge holder unit  208  is opposite that of the upward cutting direction of the tape cutter  90 . 
     Details of the input unit  50 C, the display unit  50 D, and the printer unit  50 B incorporated in the tape printing device  1  are described below after brief description of an electrical structure of the various units including the control circuit unit  50 F. The control circuit unit  50 F constituted as a printed circuit board is installed with the printer unit  50 B immediately below the cover  50 K. FIG. 14 is a block diagram schematically showing the general electric structure of the various units. The control circuit unit  50 F of the tape printing device  1  includes a one-chip microcomputer  110  (hereinafter referred to as CPU) having a ROM, a RAM, and input and output ports integrally incorporated therein, a mask ROM  118 , and a variety of circuits functioning as interfaces between the CPU  110  and the input unit  50 C, the display unit  50 D, and the printer unit  50 B. The CPU  110  connects with the input unit  50 C, the display unit  50 D, and the printer unit  50 B directly or the interface circuits to control these units. 
     The input unit  50 C has forty-eight character keys and fifteen functions keys, sixty-three keys in total, as shown in FIG.  15 . The character keys form a so-called full-key structure according to a JIS (Japanese Industrial Standards) arrangement. Like a conventional word processor, the input unit  50 C has a commonly known shift key to avoid undesirable increase in the number of keys. The functions keys enhance the ability of the tape printing device  1  by realizing quick execution of various functions for character input, editing, and printing. 
     These character keys and the function keys are allocated to an 8×8 matrix. As shown in FIG. 14, sixteen input ports PA 1  through PA 8  and PC 1  through PC 8  of the CPU  110  are divided into groups, and the sixty-three keys of the input unit  50 C are arranged at the respective intersections of the input ports. The power switch  50 J is formed independently of the matrix keys and connects with a non-maskable interrupt NMI of the CPU  110 . When the power switch  50 J is operated, the CPU  110  starts non-maskable interruption to supply or shut off the power. 
     An output from an opening/closing detection switch  55  for detecting opening and closing of the cover  50 K is input to a port PB 5 , so that the CPU  110  interrupts to monitor the opening and closing conditions of the cover  50 K. The opening/closing detection switch  55  detects the movement of the cover  50 K according to a movement of an opening/closing detection switch engagement projection  55 L (see FIG. 12) disposed on an end of the cover  50 K. When the opening/closing detection switch  55  detects opening of the cover  50 K while the printing head  60  is driven, the CPU  110  displays a predetermined error command on a main display element  50 Da (see FIG. 16) of the display unit  50 D and cuts the power supply to the printer unit  50 B. 
     Ports PH, PM, and PL of the CPU  110  are connected with a head rank detection element  112  which adjusts a varied resistance of the printing head  60  by means of a software. The resistance of the printing head  60  significantly varies according to the manufacture process, which changes a power-supply time required for printing of a predetermined density. The head rank detection element  112  measures the resistance of the printing head  60  to determine a rank of the printing head  60  and set three jumper elements  112 A,  112 B, and  112 C of the head rank detection element  112  based on the measurement results. The CPU  110  then reads the conditions of the head rank detection element  112  to correct a driving time or heating amount of the printing head  60 , thus effectively preventing the varied density of printing. 
     Since the printer unit  50 B implements thermal transfer printing, the density of printing varies with a temperature and a driving voltage as well as the power-supply time of the thermal printing head  60 . A temperature detection circuit  60 A and a voltage detection circuit  60 B respectively detect the temperature and the driving voltage. These circuits  60 A and  60 B are integrally incorporated in the printing head  60  and connect with two-channel analog-digital conversion input ports AD 1  and AD 2  of the CPU  110 . The CPU  110  reads voltages input and converted to digital signals through the input ports AD 1  and AD 2  to correct the power-supply time of the printing head  60 . 
     A discriminating switch  102  disposed on a right lower corner of the tape cartridge holder unit  50 A (see FIG. 10) is connected with ports PB 1  through PB 3  of the CPU  110 . The discriminating switch  102  includes three cartridge discriminating switch elements  102 A,  102 B, and  102 C respectively inserted into the three detection holes  18 Ka,  18 Kb, and  18 Kc formed on the tape cartridge  10 . Projections of the cartridge discriminating switch elements  102 A,  102 B, and  102 C are designed according to the depths of the detection holes  18 K formed on the bottom wall  18  of the tape cartridge  10 . When the cartridge discriminating switch element  102  is inserted in a shallow detection hole  18 K, the cartridge discriminating switch element  102  is in contact with and pressed by the detection hole  18 K to be turned ON. When the cartridge discriminating switch element  102  is inserted in a deep detection hole  18 K, on the other hand, the cartridge discriminating switch element  102  is loosely fitted in the detection hole  18 K to be kept OFF. The CPU  110  determines the type of the tape cartridge  10  set in the tape cartridge holder unit  50 A, that is, the width of the tape T accommodated in the tape cartridge  10  according to conditions of the three cartridge discriminating switch elements  102 A,  102 B, and  102 C of the discriminating switch  102 . Tape width information representing the width of the tape T is used for determining a printed character size and controlling the printer unit  50 B (described later). 
     A port PB 7  of the CPU  110  receives a signal from a contact of the plug  50 N. While the plug  50 N receives direct current from an AC adapter  113  through insertion of a jack  115 , power supply from a battery BT to a power unit  114  is cut by means of a braking contact to avoid power consumption of the battery BT. In the meantime, a signal output from the contact on the plug  50 N is input to the port PB 7  of the CPU  110 . The CPU  110  reads the signal to determine whether power is supplied from the AC adapter  113  or the battery BT and execute required controls. In the embodiment, when power is supplied from the AC adapter  113 , a printing speed of the printer unit  50 B is set at a maximum value. When power is supplied from the battery BT, on the other hand, the printing speed of the printer unit  50 B is slowed down to reduce an electric current peak supplied to the printing head  60  and save power of the battery BT. 
     The twenty four mega-bit mask ROM  118  connected to an address bus and data bus of the CPU  110  stores four different fonts of 16×16 dots, 24×24 dots, 32×32 dots, and 48×48 dots. The mask ROM  118  stores alphabetical types such as elite, pica, and courier as well as Chinese characters and other specific characters and symbols required in the respective countries. A 24 bit address bus AD, an 8 bit data bus DA, a chip selecting signal CS, an output enabling signal OE of the mask ROM  118  are connected with ports PD 0  through PD 33  of the CPU  110 . These signals are also input to an external input/output connector  50 Ea to allow the extension unit  50 E attached to the external input/output connector  50 Ea to be accessible in a similar manner to the mask ROM  118 . 
     The extension unit  50 E directly connectable with the control circuit unit  50 F receives a ROM pack or RAM pack optionally supplied as an external memory element. The control circuit unit  50 F is electrically connected with the external input/output connector  50 Ea through insertion of the ROM pack or RAM pack into a slot of the extension unit  50 E, so that information is transmittable between the CPU  110  and the ROM pack or RAM pack. The ROM pack inserted in the extension unit  50 E may store specific characters and symbols for drawings, maps, chemistry, and mathematics as well as linguistic fonts other than English or Japanese, and character fonts such as Gothic and hand-writing type faces so as to allow editing of a desirable series of characters. The battery backed-up RAM pack which information is freely written in may alternatively be inserted in the extension unit  50 E. The RAM pack stores a greater amount of information than a memory capacity of an internal RAM area of the tape printing device to create a library of printing characters or to be used for information exchange with another tape printing device  1 . 
     Character dot data read out of the mask ROM  118  or the extension unit  50 E are input to an LCD controller  116 A of a display control circuit  116  as well as the CPU  110 . 
     The display unit  50 D controlled by the CPU  110  via the display control circuit  116  is laid under a transparent portion of the cover  50 K. The user can thus see the display unit  50 D through the cover  50 K. The display unit  50 D has two different electrode patterns on a liquid-crystal panel; that is, a dot matrix pattern of 32(height)×96(width) dots and twenty eight pentagonal electrode patterns surrounding the dot matrix pattern, as shown in FIG.  16 . An area of the dot matrix pattern is designated as a main display element  50 Da for displaying a printing image while an area of the pentagonal electrode patterns is referred to as an indicator element  50 Db. 
     The main display element  50 Da is a liquid crystal display panel allowing a display of 32 dots in height×96 dots in width. In the embodiment, since a character font of 16 dots in height×16 dots in width is used for character input and editing, a display on the main display element  50 Da includes six characters×two lines. Alternatively, the main display element  50 Da may include four lines of letters when only an alphabetical font is used. Each character is shown as a positive display, a negative display, or a flickering display according to the editing process. 
     The display on the dot-matrix main display element  50 Da is controlled according to the requirement. For example, a layout of a printing image may be displayed after a certain key input operation. When the user instructs display of a layout, as shown in FIG. 17, a tape width is shown as a negative display and a series of printing characters are displayed in white, where each dot of the main display element  50 Da corresponds to 4×4 dots in printing. A whole length of the tape is displayed numerically as supplementary information of the printing image. When the layout of the printing image is larger than the area of the main display element  50 Da, the whole layout may be observed and checked through vertical or horizontal scroll with cursor keys operation. 
     The indicator element  50 Db surrounding the main display element  50 Da displays a variety of functions executed by the tape printing device  1 . Display elements t each corresponding to a pentagonal electrode pattern of the indicator element  50 Db represent a variety of functions and conditions printed around the pentagonal patterns of the display unit  50 D. These functions and conditions include a character input mode such as ‘romaji’ (Japanese in Roman characters) or ‘small letter’, a printing and editing style such as ‘line number’ and ‘keyline box’, and a print format like ‘justification’ or ‘left-weight’. When a function or a condition is executed or selected, the display element corresponding to the function or condition lights up to inform the user. 
     The printer unit  50 B of the tape printing device  1  includes the printing head  60  and the stepping motor  80  as mechanical constituents, and a printer controller  120  for controlling the mechanical constituents and a motor driver  122  as electrical constituents. The printing head  60  is a thermal head having ninety-six heating points arranged in a column at a pitch of {fraction (1/180)} inch, and internally provided with the temperature detection circuit  60 A for detecting the temperature and the voltage detection circuit  60 B for detecting the supply voltage as described previously. The stepping motor  80  regulates a rotational angle by controlling a phase of a four-phase driving signal. A tape feeding amount of each step by the stepping motor  80  is set equal to {fraction (1/360)} inch according to the structure of the gear train functioning as a reduction gear mechanism. The stepping motor  80  receives a two-step rotation signal synchronously with each dot printing executed by the printing head  60 . The printer unit  50 B thereby has a printing pitch of 180 dots/inch in the longitudinal direction of the tape as well as the direction of the tape width. 
     A detection switch  99  for detecting operation of the cutting mechanism is connected to a common line of connecting signal lines between the printer controller  120 , the motor driver  122 , and the CPU  110  as shown in FIG.  14 . When the cutting mechanism is driven during printing operation, the detection switch  99  detects operation of the cutting mechanism and inactivates the printer unit  50 B. Since signals are continuously sent from the CPU  110  to the printer controller  120  and the motor driver  122 , printing may, however, be continued after the user interrupts to use the cutting mechanism. 
     Actuation of the cutting mechanism during a printing process interferes with normal feeding of the tape T. The detection switch  99  of the embodiment is thus directly connected with the common line of the motor driver  122  to forcibly cut the power off so as to immediately stop the printing process or more specifically the tape feeding. In an alternative structure, an output of the detection switch  99  may be input to the CPU  110 , and the printer unit  50 B is inactivated according to a software as is the case of untimely opening of the cover  50 K. The detection switch  99  may be replaced by a mechanical structure which presses the clutch arm  80 B according to the movement of the movable blade  98  to prevent rotation of the stepping motor  80  from being transmitted to the platen driving shaft  72 . 
     The tape printing device  1  is further provided with a power unit  114 , which receives a stable back-up or logic circuit 5V power from the battery BT by an RCC method using an IC and a transformer. The CPU  110  includes a port PB 4  for regulating the voltage. 
     Under such a condition that the tape cartridge  10  thus constructed is not set in the tape printing device  1 , the tape core  20  is pressed against the bottom wall  18  via a washer  23  (see FIG. 3) to be not rotatable. Non-rotatable structure of the tape core  20  effectively prevents looseness or slack of the tape T. The pair of circular films  20 A adhering to the upper and lower sides of the tape core  20  have adhesive layers facing the tape T. Upper and lower sides of the tape T are thereby securely stuck to the films  20 A. 
     As described above, the platen  12  is movably fitted in the elliptic apertures  16 A and  18 A of the top wall  16  and the bottom wall  18 . When the user tries to press back the tape T pulled outside the tape cartridge  10  into the tape cartridge  10 , the platen  12  moves towards the tape guide pin  26  to clamp the tape T between the platen  12  and the tape guide pin  26  (see FIG.  3 ). This interferes with a further movement of the tape T and effectively prevents the tape T from being forcibly pressed inside the tape cartridge  10 . The guide element  10 B arranged near the tape outlet  10 A of the tape cartridge  10  ensures smooth feeding of the tape T held between the printing head  60  and the platen  12  even when a longitudinal end of the tape T enters a little inside the tape outlet  10 A. 
     When the user tries to use the tape cutter  90  during printing operation, the detection switch  99  detects the movement of the tape cutter  90  before cutting the tape to stop rotation of the stepping motor  80  and power supply to the head body  65  immediately. The tape cutter  90  is thereby not used during feed of the tape T for printing. This effectively prevents the tape T from being stuck in the tape cartridge  10 , thus improving usability of the tape printing device  1  and reducing labor required for maintenance. 
     In this embodiment, the washer  23  presses the tape core  20  against the bottom wall  18  to prevent rotation of the tape core  20 . Another structure may, however, be applied to prevent rotation of the tape core  20 . For example, as shown in FIG. 17, the film  20 A adhering to the upper end of the tape core  20  has a plurality of clicks  20 C, which engage with a plurality of projections  16 D formed on an inner face of the top wall  16  of the tape cartridge  10  only when the tape core  20  rotates in such a direction as to normally feed the tape T. This structure also effectively prevents the tape core  20  from being rotated in a wrong direction to loose the tape T. Such a click element or another anti-rotation structure may be formed on the lower end of the tape core  20  instead of the upper end shown in FIG.  17 . 
     The tape cartridge  10  may accommodate a folded long tape T in place of the tape T wound on the tape core  20  as described above. 
     Under such a condition that the tape cartridge  10  is not set in the tape printing device  1 , the first engagement elements  22 A of the ink ribbon core  22  engage with the first engagement piece  18 D formed on the bottom wall  18  of the tape cartridge  10  to prevent rotation of the ink ribbon core  22  (see FIGS.  3  and  4 ). In the same manner, the second engagement elements  24 A of the ribbon winding core  24  engage with the second engagement piece  18 H formed on the bottom wall  18  to prevent rotation of the ribbon winding core  24 . This structure efficiently prevents slack of the ink ribbon R during delivery of the tape cartridge  10  without any protective sheet or element or any special casing for the tape cartridge  10 . No use of protective elements makes the tape cartridge  10  free from faults or troubles due to non-removal of these elements. Engagement of the first engagement elements  22 A with the first engagement piece  18 D and that of the second engagement elements  24 A with the second engagement piece  18 H are automatically released by functions of the cone-shaped contact projections  70 A and  70 B (see FIG. 4) when the tape cartridge  10  is set in the tape printing device  1 . 
     Each edge of the first engagement piece  18 D and the second engagement piece  18 H obliquely faces the first engagement elements  22 A and the second engagement elements  24 A to allow rotation of the ink ribbon R in a normal direction, that is, a direction not to slacken the ink ribbon R, while the tape cartridge  10  is not set in the tape printing device  1 . Even when engagement of the first engagement elements  22 A with the first engagement piece  18 D or that of the second engagement elements  24 A with the second engagement piece  18 D is not completely released due to a worn-out or broken contact projection  70 A or  70 B or inappropriate setting of the tape cartridge  10  in the tape printing device  1 , winding of the ink ribbon R for printing is normally implemented according to the above structure. 
     When the tape cartridge  10  once used for printing is detached from the tape cartridge holder unit  50 A, the first engagement piece  18 D and the second engagement piece  18 H respectively re-engage with the first engagement elements  22 A of the ink ribbon core  22  and the second engagement elements  24 A of the ribbon winding core  24  to prevent rotation of the ink ribbon core  22  and the ribbon winding core  24 , thus preventing undesirable slack of the ink ribbon R. Since a tape cartridge  10  which has been used for printing but is still usable is often removed from the tape printing device  1  to be replaced with another tape cartridge having a different tape width, this anti-slack structure of the ink ribbon core  22  and the ribbon winding core  24  is significantly useful. 
     As described previously, each edge of the first engagement piece  18 D and the second engagement piece  18 H obliquely faces the first engagement elements  22 A and the second engagement elements  24 A to allow rotation of the ink ribbon core  22  and the ribbon winding core  24  in such a direction as to reduce slack of the ink ribbon R even after the tape cartridge  10  is detached from the tape cartridge holder unit  50 A. This allows the user to rotate the ribbon winding core  24  with a screwdriver to remove slack of the ink ribbon R. 
     In the tape printing device  1  of the embodiment, when the user forcibly pulls out the tape T, the clutch arm  80 B rotates counterclockwise in the drawing of FIG. 11 to release an engagement of the second gear  82  with the third gear  83 . This makes the platen  12  free from the force of the stepping motor  80 . The platen driving shaft  72  of the platen  12  and the ribbon winding core driving shaft  74  of the ribbon winding core  24  thus rotate according to pull-out movement of the tape T so as to prevent the ink ribbon R from being slackened or pulled out of the tape cartridge  10  due to forcible movement of the tape T. 
     Although the tape cartridge  10  of the embodiment accommodates both the ink ribbon R and the tape T, a tape cartridge accommodating only the tape T and an ink ribbon cartridge accommodating only the ink ribbon R may be manufactured separately. 
     The structure of the invention is applicable to a wide range of printing devices with ink ribbon, for example, to an ink ribbon cartridge accommodating a thermal transfer ink ribbon and a word processor using the ink ribbon cartridge, or to a dot-impact printer and an ink ribbon used therein. 
     A second embodiment of the invention is described hereinafter. A cartridge  210  of the second embodiment is schematically illustrated in FIGS. 18 through 21. This cartridge  210  is detachably set in the printing device  1  of the first embodiment. 
     As shown in FIGS. 18 through 21, the cartridge  210  has a cartridge case  201  consisting of an upper case  201   a  and a lower case  201   b,  which receives a variety of elements including a tape core  202  and an ink ribbon core  207  therein. The tape core  202  has a tape  203  wound thereon and is set around a projection  201   c  in the lower case  201   b.    
     A bearing hole  202   b  of the tape core  202  receives an anti-inversion spring  204 , which has one end  204   a  extending to be fitted in a slit  201   d  of the projection  201   c  of the lower case  201   b.  The cartridge  210  further accommodates a platen  205  receiving a driving force of a printing device (not shown) to feed the tape  203  out and receiving a pressure of a printing head (not shown) during printing operation, and a ribbon winding core  207  for winding an ink ribbon  206  used for printing. The cartridge  210  is mounted on a cartridge holder unit  208  of a printing device or a tape writer (not shown). The position of the cartridge  210  is determined by the projection  201   c  of the lower case  201   b  and a positioning projection  208   a  formed on the cartridge holder unit  208 . 
     The cartridge  210  of the second embodiment has a structure below for preventing a longitudinal end of the tape  203  from being reversely moved back into the cartridge case  201 . As clearly seen in FIG. 21, the tape core  202  has a ratchet groove  202   a  around the bearing hole  202   b.  The one end  204   a  of the anti-inversion spring  204  engages with the ratchet groove  202   a  to interfere with rotation of the tape core  202  in a direction shown by the arrow B. The ratchet groove  202   a  has a plurality of teeth formed in one direction as shown in FIG. 21 allows the tape core  202  to press up the spring  204   a  and freely rotate in a direction shown by the arrow A. This ratchet mechanism of the tape core  202  engaging with the one end  204   a  of the anti-inversion spring  204  allows rotation of the tape core  202  only in the direction A, thus preventing the end of the tape  203  from being reversely moved back into the cartridge case  201 . Engagement of the one end  204   a  of the anti-inversion spring  204  with the slit  201   d  of the projection  201   c  formed in the lower case  201   b  of the cartridge  210  effectively prevents the anti-inversion spring  204  from rotating integrally with the tape core  202 . 
     The cartridge  210  of the second embodiment further includes a supplementary structure to ensure anti-inversion of the tape core  202 . 
     The cartridge holder unit  208  has the positioning projection  208   a  as clearly seen in FIGS. 18 and 19. When the cartridge  210  is set on the cartridge holder unit  208 , the positioning projection  208   a  functions to lift the anti-inversion spring  204  up and release the engagement of the one end  204   a  of the anti-inversion spring  204  with the ratchet groove  202   a,  thus allowing free rotation of the tape core  202 . Undesirable reverse movement of the tape  203  occurs when the cartridge  210  is not set in a tape printing device  200 , for example, during delivery or accidental fall of the cartridge  210 . Release of the engagement of the spring  204  with the ratchet groove  202   a  in the cartridge  210  set on the cartridge holder unit  208  preferably decreases a force required for tape feeding and reduces a torque load applied on a platen driving motor (not shown). 
     Although a coiled spring is used as the anti-inversion spring  204  in the second embodiment, another spring such as a leaf spring or another element having similar effects may be used instead of the coiled spring. 
     A third embodiment of the invention is described according to FIG.  22 . The structure of the third embodiment includes a plurality of clutch members  269  formed between a tape core  262  and a tape core guide face of an upright shaft member  261  formed on a cartridge case. An upright shaft member  261  has three grooves  261   a  formed on an outer face of the shaft member  261  and extending along the shaft member  261 . When the tape core  262  is set around the shaft member  261 , the three clutch members  269  are located in spaces defined by the three grooves  261   a  and an inner surface of the tape core  262 . The space formed by each groove  261   a  of the shaft member  261  has a wedge-like shape in a circumferential direction of the tape core  262  as clearly seen in FIG.  22 . When the tape core  262  is rotated in a direction shown by the arrow A, the clutch members  269  do not enter the wedge-shaped spaces to allow free rotation of the tape core  262 . When the tape core  262  is rotated in a direction shown by the arrow B, on the other hand, the clutch members  269  are fitted in the wedge-shaped spaces to interfere with rotation of the tape core  262 . 
     A fourth embodiment of the invention is described according to FIG.  23 . The structure of the fourth embodiment includes another clutch mechanism for allowing rotation of a tape core  272  only in one direction. As shown in FIG. 23, the tape core  272  having a coil spring  279  therein is set around an upright shaft  271  formed in a cartridge case. One end  279   a  of the coil spring  279  engages with a groove  272   a  of the tape core  272 . The coil spring  279  has an inner diameter a little greater than an outer diameter of the shaft  271  and is thereby set around the shaft  271  with a predetermined clearance. When the tape core  272  is rotated in a direction shown by the arrow A, the inner diameter of the coil spring  279  is expanded to allow free rotation of the tape core  272 . When the tape core  272  is rotated in an opposite direction, on the other hand, the inner diameter of the coil spring  279  is contracted to clamp the shaft  271  so as to interfere with rotation of the tape core  272 . 
     A fifth embodiment of the invention is described according to FIG.  24 . The structure of the fifth embodiment includes a pair of locking pawls  281   a  formed on a bottom surface of a cartridge case  281  to engage with a pair of grooves  282   a  of a tape core  282 . Either or both of the locking pawls  281   a  and the grooves  282   a  have surfaces inclined in a predetermined direction to form a ratchet mechanism allowing rotation of the tape core  282  only in one direction. In the example of FIG. 24, each locking pawl  281   a  has an inclined surface. 
     The structure of the tape cartridge in each of the above embodiments effectively prevents a tape from being reversely moved back into a cartridge case. This allows simple handling and storage of the tape cartridge which is detachably set in a printing device. 
     There may be many other changes, modifications, and alterations without departing from the scope or spirit of essential characteristics of the invention, and it is thereby clearly understood that the above embodiments are only illustrative and not restrictive in any sense. The spirit and scope of the present invention is only limited by the terms of the appended claims.