PATENT ABSTRACT
A tape printing assembly for editing input data of up to ‘n’ lines which includes a main display formed to display the edited input data in ‘p’ lines, where ‘p’ is an integer between 1 to at most ‘n’−1. A display controller is adapted to control the editing procedure and display of the input data of a line currently being edited on the main display, while simultaneously indicating on an auxiliary display the line currently edited. In another aspect, a line number indicator, corresponding to a line of input data, is positioned proximate and adjacent to the line on the main display. Upon a selected portion of the input data being positioned within a display area, the line number indicator is positioned proximate to and moves with the selected portion. Upon the selected portion being scrolled beyond an end of the display area, the line number indicator is fixed relative the display area proximate the end thereof.

PATENT DESCRIPTION
This is a Divisional application Ser. No. 08/725,572 filed on Oct. 3, 1996, now U.S. Pat. No. 5,813,021, which is a further divisional of application Ser. No. 08/365,366 filed on Dec. 28, 1994, now U.S. Pat. No. 5,885,016. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of editing text data to be printed in a plurality of lines as well as to a printing device for printing the edited text data in the plurality of lines. 
     2. Description of the Related Art 
     Among a variety of printing devices generally known, there are small-sized printing devices for printing desired text data on a surface of an adhesive tape having an adhesive rear face. With such a tape printing device, a desirable title or name is printed on a label (cut piece of a tape) through simple operation. These labels with an adhesive are applied in both domestic and business fields, for example, on the spine of business files or the back of video tapes. 
     A high-functional, value-added printing device has been developed to allow text data to be printed in a plurality of lines on the tape. Tape cartridges used for the printing device may accommodate transferable tapes and those of various colors and widths other than the conventional adhesive tapes. 
     The value-added function of printing text data in a plurality of lines, however, leads to increase the size of the device undesirably, thereby damaging the advantages of the portable printing device. The size increase of the high-functional printing device is mainly attributable to a large display unit for editing text data of plural lines. 
     Simple down-sizing of the display makes it difficult to check and observe information and data on the display. Another possible structure for the down-sizing shows only part of text data to be edited. This deteriorates the efficiency of editing procedures and may result in waste of the tape since mistakes are often found after the printing on the tape. 
     There is a known function applicable to the printing device, which calculates a required length for input text data and displays the required length of the tape. A fixed unit of length is, however, confusing since some nations adopt the metric system whereas other nations use the inch-yard system. Calculation results of the required length based on the input text data may cause display of rather complicated numbers with decimal point. 
     SUMMARY OF THE INVENTION 
     One object of the invention is accordingly to provide a printing device having a small display unit which allows the user to easily check and observe data and information without deteriorating the efficiency of editing procedures. 
     Another object of the invention is to provide a method of editing data with such a printing device. 
     The above and other related objects are realized by a tape printing device for editing data of up to ‘n’ lines, where ‘n’ is an integer at least 2, and printing the edited data in ‘m’ lines, where ‘m’ is an integer between 1 to the maximum line number ‘n’. In the tape printing device of the invention, the edited data are displayed on a main display unit in ‘p’ lines, where ‘p’ is an integer between 1 to ‘n’−1. A line currently edited is displayed as a digit on an auxiliary display unit. The data which occupies a relative large display area and includes data of the line currently edited are displayed on the main display unit while the current editing position is indicated on the auxiliary display unit. 
     The invention is also directed to another tape printing device for editing data of up to ‘n’ lines, where ‘n’ is an integer at least 2, and printing the edited data in ‘m’ lines, where ‘m’ is an integer between 1 to ‘n’. In the tape printing device of the invention, the edited data are displayed on a display unit in ‘p’ lines, where ‘p’ is an integer between 1 and the maximum line number ‘n’. The data displayed on the display unit can be scrolled along each line. A digit representing a line number at a head of the data displayed on the display unit is indicated in either of the following forms. When the data is scrolled to make the head of the data reach an end of the display unit and further scrolled to be out of a display area of the display unit, the digit representing a line number is indicated at a fixed position on the end of the display unit. When the data is scrolled to make the head of the data reach the end of the display unit and further scrolled to be within the display area of the display unit, the digit representing a line number is indicated at the head of the data. 
     According to another aspect of the invention, a tape printing device for printing data on a tape or recording medium inputs data, prints the input data on the tape, and cuts the tape with the data printed thereon at a specified length. The specified length of the tape with the data printed thereon is displayed together with a unit of length on the display unit prior to the printing procedures. The unit of length can be selected among a plurality of choices. 
     In another aspect of the present invention, a method is provided for displaying edited input data of up to ‘n’ lines, where ‘n’ is a maximum line number and an integer of at least 2, which are to be printed on an elongated tape or elongated recording medium. The method includes the steps of: (A) providing a main display unit configured to display at least a portion of the edited input data in ‘p’ lines, where ‘p’ is an integer between 1 to at most ‘n’−1; and (B) controlling the editing procedure of the input data. This controlling step further includes displaying at least a portion of the input data, including displaying at least a portion of the input data of a line currently edited on the main display unit. This method of the present invention further includes the step of (C) indicating in digits the line currently edited on an auxiliary display unit positioned proximate to the main display unit. 
     The present invention also includes the another method of displaying edited input data of up to ‘n’ lines, where ‘n’ is a maximum line number and an integer, to be printed on an elongated tape or elongated recording medium. In this embodiment, the method first includes the step of: (A) providing a main display configured to display on a display area thereof at least a portion of the edited input data in ‘p’ lines, where ‘p’ is an integer between 1 to the line number ‘n’. The next step includes (B) controlling the editing procedure of the input data and displaying at least a portion of the input data, including displaying at least a portion of the input data of a line currently edited on the display area. Finally, this present invention method includes the step of (C) indicating in a digit a line number indicator corresponding to a respective line of edited input data displayed on the main display. The line number indicator is positioned proximate and adjacent to the respective line on the main display and is formed to display the corresponding digit in either one of the following two forms. The first form pertains to (i) displaying in the display area the line number indicator proximate to and moving with a selected portion of the respective input data of the respective line during scrolling thereof across the main display when the selected portion is positioned within the display area during scrolling of the input data. The other form pertains to (ii) displaying the line number indicator at a fixed location relative the display area and proximate to an end thereof, adjacent to the respective line on the main display, when the selected portion of the respective input data is scrolled beyond the end and out of display of the display area. 
     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  embodying the invention; 
     FIG. 2 is a right side view of the tape printing device  1 ; 
     FIG. 3 is a plane view showing assembly of a tape cartridge  10  attached in the tape printing device  1 ; 
     FIG. 4 is a perspective view illustrating a structure of a tape cartridge holder unit  50 A; 
     FIG. 5 is a perspective view illustrating a gear train structure and a function of moving a printing head  60  between a printable position and a rest position; 
     FIG. 6 is a decomposed perspective view showing the printing head  60 ; 
     FIG. 7 is a block diagram showing an electric structure including a CPU  110 ; 
     FIG. 8 shows an exemplified arrangement of keys on an input unit  50 C; 
     FIG. 9 shows a typical structure of a display unit  50 D; 
     FIG. 10 is a flowchart showing a process routine executed by the tape printing device  1 ; 
     FIG. 11 is a flowchart showing detailed steps of the data displaying process of FIG. 10; 
     FIGS. 12A and 12B show exemplified displays on the display unit  50 D according to the text data displaying process; 
     FIG. 13 is a flowchart showing detailed steps of a part of the processing in the printing information specification mode; 
     FIG. 14 is a flowchart showing detailed steps of another part of the processing in the printing information specification mode; 
     FIGS. 15 through 22 show various application forms applicable to the processing of FIG. 14; 
     FIG. 23 shows a process of registering certain text data into a list of abbreviations by assigning a specific abbreviation thereto; 
     FIG. 24 shows a process of inputting the specific abbreviation to display the corresponding text data; 
     FIG. 25 shows a process of deleting the specific abbreviation from the list of abbreviations; 
     FIG. 26 shows a typical structure of a display unit  750 D in a second embodiment according to the invention; 
     FIG. 27 is a flowchart showing a display control routine executed in the second embodiment; 
     FIGS. 28A through 28D show exemplified displays according to the display control process of FIG. 27; 
     FIG. 29 is a flowchart showing a shifting process routine executed at step S 830  in the flowchart of FIG. 27; 
     FIG. 30 is a plan view showing appearance of a tape printing device  900  as a third embodiment according to the invention; 
     FIG. 31 is a block diagram showing electric constituents of the tape printing device  900 ; 
     FIG. 32 is a flowchart showing a process routine executed by the tape printing device  900  of the third embodiment; 
     FIG. 33 shows a menu where the unit ‘cm’ is highlighted; 
     FIG. 34 shows a menu where the unit ‘inch’ is highlighted; 
     FIG. 35 is a flowchart showing a printing process in the third embodiment; 
     FIG. 36 shows an exemplified display by ‘cm’; 
     FIG. 37 shows an exemplified display by ‘inch’; 
     FIG. 38 shows a conversion table between the dot number, ‘inch’, and ‘cm’; and 
     FIG. 39 is a flowchart showing another process of setting the unit of length. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Structure and functions of the present invention will become more apparent through description of the following preferred embodiments of the invention. 
     A tape printing device of a first embodiment, in which a plurality of tape cartridges are detachably and replaceably attached, prints text data on a tape accommodated in each tape cartridge. Both an ink ribbon and a tape on which text data are printed with the ink ribbon are accommodated in one cartridge in this embodiment. This cartridge for the ink ribbon and the tape is hereinafter referred to as the tape cartridge. 
     A. Hardware Configuration 
     As illustrated 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-two keys, a freely openable cover  50 K, a display unit  50 D arranged visibly through a window  50 M formed on the cover  50 K for displaying a series of text data and required information, and a tape cartridge holder unit  50 A (not shown in FIG. 1) which is disposed on a left upper portion of the device  1  and detachably and replaceably receives a tape cartridge  10 . The cover  50 K is provided with another window  50 L for checking attachment of the tape cartridge  10  as well as the window  50 M through which the display unit  50 D is observable. Both the windows  50 L and  50 M are covered with transparent plastic plates. A detection switch  55  (see FIG. 7) monitors opening and closing operations of the cover  50 K. 
     Operation of the tape printing device  1  thus constructed is described briefly. An operator first opens the cover  50 K and attaches the tape cartridge  10  into the tape cartridge holder unit  50 A. After closing the cover  50 K, the operator actuates a head shift lever  63 C (see FIG. 4 described later) to shift a head to a printable position and subsequently presses a power switch button  50 J to supply electric power. The device  1  is now ready for an input of letters or characters. The operator then operates the keys on the input unit  50 C to input a desirable series of letters or characters to be printed. The series of letters may be input directly as text data or otherwise converted to specific characters such as Chinese characters, symbols, or words according to the requirements. In response to a printing instruction through a specific key operation, the tape printing device  1  drives a thermal transfer printer unit  50 B (described later) to start printing on a tape T fed from the tape cartridge  10 . The tape T with the letters and 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 to ensure favorable ink-spread properties by thermal transfer, and an adhesive rear face which a peel tape is closely applied on. After the printed tape T is cut to a label of a desirable length with a built-in blade cutter and the peel tape on the rear face of the tape T is peeled off, the label with characters and symbols printed thereon is applied onto any desirable place. 
     The tape printing device  1  is further provided on a bottom face thereof with a battery holder unit (not shown) for receiving six SUM-3 cells working as a power source of the whole device  1 . The required power is alternatively supplied by inserting an AC power cord (not shown) into a jack  50 N on the right side wall of the device  1 . 
     Structure and functions of the tape cartridge  10  are described mainly based on the plan view of FIG.  3 . The tape cartridge  10  includes a tape core  20  which a long tape T is wound on, an ink ribbon core  22  which an ink ribbon R used for printing is initially wound on, a ribbon winding core  24  which the ink ribbon R is wound up, and a platen  12 . The tape T is held between the platen  12  and a printing head  60  for the printing procedures. The tape cartridge  10  can receive tapes of different widths in similar configurations. In the embodiment, five tape cartridges respectively accommodating tapes of 6 mm, 9 mm, 12 mm, 18 mm, and 24 mm in width are prepared in the embodiment. 
     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 and the ink ribbon R with the printing head  60  for desirable printing. In the embodiment, two types of platen rubber  14  are used; a 12 mm wide platen rubber for 6 mm, 9 mm, and 12 mm tapes, and a 18 mm wide platen rubber for 18 mm and 24 mm tapes. 
     The platen  12  is fitted in apertures formed on a top wall and a bottom wall of the tape cartridge  10  to allow pivotal movement of the platen  12 . As described previously, the tape T on the tape core  20  and the ink ribbon R on the ink ribbon core  22  and the ribbon winding core  24  are arranged in a compact manner in the tape cartridge  10 . The ink ribbon core  22  and the ribbon winding core  24  are also fitted in apertures formed on the top wall and the bottom wall of the tape cartridge  20  to allow pivotal movement of the respective cores  22  and  24 . The tape cartridge  10  further includes a printing head receiving hole  32  which the printing head  60  goes in and out. The printing head receiving hole  32  is defined by a guide wall  34 . 
     The tape core  20  is a hollow, large-diametral cylindrical reel having a configuration to receive the long tape T in a relatively small space. This structure allows even a tape T having a small curvature and small resistance against the bending stress to be accommodated under preferable conditions. The tape wound on the tape core  20  runs to the platen  12  via a tape guide pin  26  projecting upright from the bottom wall  18  of the tape cartridge  10  and is further led to a tape outlet  10 A of the tape cartridge  10 . 
     As shown in FIG. 3, substantially L-shaped engagement pieces  18 D and  18 H are 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 . The engagement pieces  18 D and  18 H are formed by cutting specific portions of the bottom wall  18  of the tape cartridge  10  (hatched portions designated as X and Y in FIG.  3 ). Resilience of the material of the bottom wall  18  allows respective free ends of the engagement pieces  18 D and  18 H to be movable around base portions  18 E integrally formed with the bottom wall  18  and along the plane of the bottom wall  18 . Upon condition that no force is applied onto the engagement pieces  18 D and  18 H, the free ends of the engagement pieces  18 D are respectively positioned inside the circumferences of the ink ribbon core  22  and the ribbon winding core  24 . The respective free ends accordingly engage with any of six engagement fingers formed on the ink ribbon core  22  and the ribbon winding core  24  movably fitted in the apertures, so as to prevent unintentional rotations of the ink ribbon core  22  and the ribbon winding core  24 . The engagement of the ink ribbon core  22  with the engagement piece  18 D and that of the ribbon winding core  24  and the engagement piece  18 H are released by attaching the tape cartridge  10  in the tape cartridge holder unit  50 A. The releasing mechanism will be described later with the structure of the tape cartridge holder unit  50 A. 
     The ink ribbon R wound on and pulled out of the ink ribbon core  22  is guided by a ribbon guide roller  30  and is fed with the tape T to the platen  12 . The ink ribbon R is further led to the ribbon winding core  24  via the guide wall  34  formed on the circumference of the printing head receiving hole  32  which the printing head  60  goes in and out. In the drawing of FIG. 3, p and q show the running conditions of the ink ribbon R when the tape cartridge  10  is new and unused, 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 , respectively. 
     The ink ribbon R wound up the ribbon winding core  24  is a thermal transfer ribbon having a specific width determined according to the width of the tape T on which characters are printed. In this embodiment, a 12 mm wide ink ribbon R is used for 6 mm, 9 mm, and 12 mm wide tapes T, a 18 mm wide ink ribbon R for a 18 mm wide tape T, and a 24 mm wide ink ribbon R for a 24 mm wide tape T. 
     As described previously, five tape cartridges  10  of different tape widths are applicable to the tape printing device  1  of the embodiment. A printable range of the tape T differs according to the width of the tape T, and it is thus required to detect the type of the tape cartridge  10 . The tape cartridge  10  of the embodiment has first through third detection holes  18 K a ,  18 K b , and  18 K c , which are formed on the bottom wall  18  to allow discrimination of the tape cartridges  10 . Namely, depths of the three detection holes  18 K a ,  18 K b , and  18 K c  are varied according to the width of the tape T accommodated in the tape cartridge  10 . A sensor arranged at a suitable position detects the widths of the respective detection holes  18 K to distinguish the maximum of seven tape cartridges  10  from one another. 
     The tape cartridge  10  thus constructed is attached in the tape cartridge holder unit  50 A of the tape printing device  1 . Mechanical constituents of the tape printing device  1  are described below. FIG. 4 is a perspective view illustrating a typical structure of the tape cartridge holder unit  50 A and the peripheral elements, where a cutter button  96  for cutting the printed tape T is shown by the broken line. FIG. 5 is a perspective view illustrating a fundamental structure of a driving mechanism  50 P for driving the platen  12  and other elements by means of power of a stepping motor  80  in solid lines as well as a rotational frame  62  rotating around a head-rotating shaft  64  in response to a pivotal operation of the head shift lever  63 C in broken lines. 
     The tape cartridge holder unit  50 A is arranged behind the input unit  50 C and on the left of the display unit  50 D on the tape printing device  1  and defines an attachment space corresponding to the shape of the tape cartridge  10  as shown in FIG. 4. A platen-driving shaft and a 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 disposed upright in the attachment space of the tape cartridge holder unit  50 A. A base board  61  is attached to the lower portion of the tape cartridge holder unit  50 A with a screw. A tape cutter  90  (see FIG. 4) and the driving mechanism  50 P for transmitting rotations of the stepping motor  80  to the platen  12  and other elements as illustrated in FIG. 5 are mounted on the base board  61 . Under the normal conditions, the base board  61  is parted by the housing of the tape cartridge holder unit  50 A, so that the driving mechanism  50 P is not directly observable by simply opening the cover  50 K. FIG. 5 illustrates the driving mechanism  50 P with the casing omitted. The rotational frame  62  for moving a head member  65  between a printable position and a rest position in response to operations of the head shift lever  63 C is shown by the broken lines in FIG.  5 . 
     The tape cartridge  10  is replaceably attached in the tape cartridge holder unit  50 A while the cover  50 K is open. When a slide button  52  (see FIG. 1) 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 about a cover hinge  54  mounted on a rear portion of the device  1  to be opened. 
     As described previously, the engagement pieces  18 D and  18 H formed on the bottom wall  18  of the tape cartridge  10  attached in the tape cartridge holder unit  50 A engage with the ink ribbon core  22  and the ribbon winding core  24  so as to prevent unintentional rotations of the ink ribbon core  22  and the ribbon winding core  24 . The engagement pieces  18 D and  18 H are formed respectively by cutting the specific portions of the bottom wall  18  (hatched portions designated as X and Y in FIG.  3 ). The tape cartridge holder unit  50 A has two wedge-like contact projections  70 A and  70 B disposed at positions substantially in the middle of the hatched portions X and Y as shown in FIG.  4 . When the tape cartridge  10  is attached in the tape cartridge holder unit  50 A, the contact projections  70 A and  70 B are respectively fitted in the hatched portions X and Y of the bottom wall  18  of the tape cartridge  10  to press the engagement pieces  18 D and  18 H in directions away from the ink ribbon core  22  and the ribbon winding core  24 . This pressing movement releases the engagement of the engagement pieces  18 D and  18 H with the ink ribbon core  22  and the ribbon winding core  24 , thus allowing rotations of the ink ribbon core  22  and the ribbon winding core  24 . 
     A transmission mechanism for transmitting rotations of the stepping motor  80  to a platen-driving shaft  72  of the platen  12  is described in detail. As shown in FIG. 5, a first gear  81  is attached to a rotational shaft  80 A of the stepping motor  80  whereas a clutch arm  80 B is fixed to the rotational shaft  80 A with a certain friction. A second gear  82  engaging with the first gear  81  and a third gear  83  (shown by the broken line in FIG.  5 ), which is integrally and concentrically formed with the second gear  82  and disposed below the second gear  82 , are attached to the clutch arm  80 B. The clutch arm  80 B, the second gear  82 , the third gear  83 , and a largest-diametral fourth gear  84  engaging with the third gear  83  constitute a one-way clutch. When the stepping motor  80  is rotated in a direction shown by the arrow C in FIG. 5, 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  and the third gear  83  in the direction of the arrow C to engage with the fourth gear  84 . Rotations of the stepping motor  80  are consequently transmitted to the fourth gear  84 . Functions of the one-way clutch will be described more in detail below. 
     The rotation of the fourth gear  84  rotates a fifth gear  85 , which is formed concentrically with the fourth gear  84 , in the same direction. The rotational force of the fifth gear  85  is then transmitted to a six gear  86  and a seventh gear  87 . A rotational shaft of the sixth gear  86  is coupled with a ribbon winding core-driving shaft  74 , which winds up the ink ribbon R in response to the rotations of the stepping motor  80 . A rim  74 A actually driving the ribbon winding core  24  is provided on the ribbon winding core-driving shaft  74  with a certain friction. Under normal operating conditions, the rim  74 A rotates integrally with the ribbon winding core-driving shaft  74 , which is actuated by the stepping motor  80 . When the ribbon winding core  24  is made unrotatable, for example, due to completed winding of the ink ribbon R, on the other hand, the rim  74 A slips against the rotation of the ribbon winding core-driving shaft  74 . 
     The rotation of the seventh gear  87  is further transmitted to a ninth gear  89  via an eighth gear  88 , which is formed concentrically with the seventh gear  87 , thus rotating the platen-driving shaft  72 . The platen driving shaft  72  has a rim  72 A which engages with an uneven inner face of the platen  12  to actuate the platen  12 . Rotations of the stepping motor  80  transmitted to the fourth gear  84  by means of the one-way clutch thus eventually rotate the platen-driving shaft  72  as well as the ribbon winding core-driving shaft  74 . As a result, the tape T held between the platen rubber  14  arranged on the circumference of the platen  12  and the head member  65  of the printing head  60  is continuously fed with progress of printing while the ink ribbon R is wound on the ribbon winding core  24  synchronously with the 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 engagement grooves 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 engagement grooves 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 overlap each other and go through a space between the platen rubber  14  and the printing head  60 . Specific dot elements on the printing head  60  are heated with the power supplied to 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 the printing, the tape T with the print thereon is fed 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 discharged from the tape outlet  10 A formed in the left side wall of the tape printing device  1 . The tape T with the print thereon is normally cut with a cutting mechanism (described later). The user may, however, forcibly pull out the tape T prior to cutting. Under the printable condition on the tape T when the printing head  60  presses the tape T against the platen rubber  14  of the platen  12 , the forcible pull-out of the tape T makes the platen-driving shaft  72  rotate. The down-geared platen-driving shaft  72  and a certain amount of retaining torque of the stepping motor  80  prevent rotations 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 T leads to unintentional pull-out of the ink ribbon R, accordingly. When the tape T is cut with the cutting mechanism under such conditions, the pulled-out portion of the ink ribbon R is also cut undesirably. 
     In order to solve the above problem, the structure of the embodiment has the one-way clutch including the clutch arm  80 B and the second through fourth gears  82  through  84 . Upon condition that the user forcibly pulls out the tape T, the platen-driving shaft  72  rotates with the platen  12 . The rotation of the platen-driving shaft  72  is transmitted to the fourth gear  84  via the gear train to rotate the fourth gear  84  counterclockwise. The rotation of the fourth gear  84  acts to rotate the third gear  83 . However, since the rotational shaft  80 A of the stepping motor  80  does not rotate, the rotational force of the fourth gear  84  presses the clutch arm  80 B supporting the third gear  83  to release the engagement of the third gear  83  with the fourth gear  84 . The release of engagement results in separating the fourth through ninth gears  84  through  89  from the stepping motor  80 . The rotation of the platen-driving shaft  72  accompanied with the pull-out movement of the tape T accordingly rotates the ribbon winding core-driving shaft  74 . The rotation of the ribbon winding core-driving shaft  74  allows the ink ribbon R to be wound up on the ribbon winding core  24  in response to the pull-out movement 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 fourth gear  84  to re-engage the third gear  83  with the fourth gear  84 . The movement of the clutch arm  80 B is defined to a favorable amount by an opening  80 C which is formed on the base board  61  and receives the free end of the clutch arm  80 B. 
     The tape T with the print thereon is fed leftward out of the tape cartridge  10  and cut with the cutting mechanism shown in FIG. 4. A cutter-support shaft protruded from the bottom of the tape cartridge holder unit  50 A holds a substantially L-shaped, pivotally movable tape cutter  90  and a spring (not shown). The resilient force of the spring keeps the tape cutter  90  under such condition that a counterclockwise rotational force is applied onto the tape cutter  90  as shown by the arrow D in FIG.  4 . With this counterclockwise rotational force, a right end  90 A of the tape cutter  90  presses the cutter button  96  upward. The right end  90 A of the tape cutter  90  is forked to receive a pin  96 A formed on a rear face of the cutter button  96 . When the cutter button  96  is pressed downward, a left end  90 A of the tape cutter  90  shifts downward, accordingly. 
     The left 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 press of the cutter button  96  rotates the tape cutter  90  clockwise in FIG. 4 against the spring force, so that the movable blade  98  and the fixed blade  91  cooperate to cut the tape T. A tape support finger (not shown) moves in response to a press of the cutter button  96  to fix the tape T at a suitable position prior to the cutting of the tape T with the movable blade  98  and the fixed blade  91 . A shift of the tape support finger is detected by a detection switch  99  (see FIG.  7 ), which generates a detection signal to interfere with the printing procedure while the tape T is being cut. 
     The printing head  60  functioning to print letters and characters on the tape T accommodated in the tape cartridge  10  moves between a printable position and a rest position by a head driving mechanism described below. The printing head  60  is positioned in proximity to the platen-driving shaft  72  at the printable position and apart from the platen-driving shaft  72  at the rest position to allow attachment and detachment of the tape cartridge  10  into and from the tape cartridge holder unit  50 A. As illustrated in FIGS. 5 and 6, the printing head  60  has the head member  65 , which is attached via a radiator plate  65   b  to an upright member  62 A of the rotational frame  62  rotatably supported on the head-rotating shaft  64  projecting from the base board  61 . The rotational frame  62  shown by the broken line in FIG. 5 is pressed strongly in the direction of the dotted arrow E by a spring (not shown) and is stably in contact with a cam member  63 A. While the rotational frame  62  is under the stable condition, the upright member  62 A of the rotational frame  62 , which can pivot about the head-rotating shaft  64 , is at the closest position to the platen-driving shaft  72 . The printing head  60  attached to the upright member  62 A of the rotational frame  62  is accordingly kept at the printable position to start printing characters on the tape T. 
     A rotational shaft  63 A a  of the cam member  63 A is coupled with a lower end of a lever rotating shaft  63 B, which goes through a cylindrical member  50 A a  projecting upright from the tape cartridge holder unit  50 A shown in FIG.  4 . The head shift lever  63 C is integrally formed on the lever rotating shaft  63 B. When the operator rotates the head shift lever  63 C counterclockwise by 90 degrees as shown by the arrow F in FIG. 4, the cam member  63 A is also rotated counterclockwise by 90 degrees as shown by the arrow G in FIG.  5 . The rotation of the cam member  63 A makes a recess  63 A b  of the cam member  63 A securely engage with a projection  62 B of the rotational frame  62 . Under this stable condition, the upright member  62 A of the rotational frame  62  is at the farthest position from the platen-driving shaft  72 . The printing head  60  attached to the upright member  62 A of the rotational frame  62  is accordingly kept at the rest position to allow the tape cartridge  10  to be attached in or detached from the tape cartridge holder unit  50 A. 
     FIG. 6 is a decomposed perspective view showing the detailed structure of the printing head  60  rotating to move between the printable position and the rest position as described above. The printing head  60  of FIG. 6 is drawn from the opposite side to those of FIGS. 4 and 5. As mentioned above, the head member  65  of the printing head  60  is attached via the radiator plate  65   b  to the upright member  62 A of the rotational frame  62 , which is rotatably supported on the head-rotating shaft  64  projecting from the base board  61 . The head member  65  on which a plurality of heating bodies HT are arranged has a large heating value and is thus fixed to the radiator plate  65   b . In order to ensure the smooth rotational movement of the head member  65  attached to the rotational frame  62 , a flexible cable  68  having excellent flexibility is used for the electric wiring to the head member  65 . 
     The radiator plate  65   b  is fixed to the upright member  62 A of the rotational frame  62  at two separate positions. At the first fixation point, the head-rotating shaft  64  is fitted in two rectangular apertures  65   ba  formed in the radiator plate  65   b . The rectangular apertures  65   ba  are formed to orient their shorter sides along the tape-feeding direction. The length of the shorter side is substantially equal to the diameter of the head-rotating shaft  64  whereas that of the longer side is approximately twice the diameter of the head-rotating shaft  64 . At the second fixation point, a pin  67   b  is fitted in apertures  62 A a  of the rotational frame  62  and an aperture  65   bb  of the radiator plate  65   b , which are formed perpendicular to the head-rotating shaft  64 . The radiator plate  65   b  is positioned accurately by the shorter sides of the rectangular apertures  65   ba  in the tape-feeding direction while being arranged rotatably about the longer sides of the rectangular apertures  65   ba  and the pin  67   b  in the direction of the tape width. This structure allows the head member  65  to be precisely kept at the printable position opposite to the platen  12 , upon condition that the printing head  60  is pressed towards the platen  12 . Even when the tape T held between the printing head  60  and the platen  12  is slightly inclined in the direction of the tape width, the pivotal movement of the radiator plate  65   b  about the pin  67   b  allows the heating bodies HT to uniformly press the tape T against the platen  12 . 
     Detailed structure of the input unit  50 C, the display unit  50 D, and the printer unit  50 B incorporated in the tape printing device  1  is described below after the brief explanation of electric structure of the various units including a 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. 7 is a block diagram schematically showing electric structure of various units in general. 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-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 via the interface circuits to control these units. 
     The input unit  50 C has forty-eight character keys and fourteen function keys, sixty-two keys in total, as shown in FIG.  8 . The character keys have a so-called full-key arrangement according to a QWERTY arrangement. Like word processors, the input unit  50 C has a commonly known shift key to avoid an undesirable increase in the number of keys. The function keys enhance the ability of the tape printing device  1  by realizing quick execution of various functions such as character input, editing, and printing. 
     These character keys and the function keys are allocated, to an 8×8 matrix. As shown in FIG. 7, 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-one keys of the input unit  50 C are arranged at the respective intersections of the input ports. The key arrangement is shown in FIG.  8 . The power switch button  50 J is disposed independently of the matrix keys and connects with a non-maskable interrupt NMI of the CPU  110 . When the power switch button  50 J is pressed, the CPU  110  starts non-maskable interruption to supply or shut off the power. 
     An output from the detection switch  55  for detecting opening and closing operations of the cover  50 K is input into a port PB 5 , so that the CPU  110  interrupts to monitor the opening and closing conditions of the cover  50 K. When the detection switch  55  detects an opening operation of the cover  50 K while the printing head  60  is driven to work, the CPU  110  displays a predetermined error command on a main display element  50 D a  (see FIG. 9) 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 to a head rank detection element  112 . The resistance of the printing head  60  significantly varies according to the manufacturing process. The head rank detection element  112  measures the resistance of the printing head  60  to determine the 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 condition of the head rank detection element  112  to correct a driving time or heating amount of the printing head  60 , thus effectively preventing the density of printing from being varied undesirably. 
     The printer unit  50 B implements printing by the known thermal transfer process, where the density of printing varies with the air temperature and the 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 output detection signals to two-channel analog-to-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. 4) is connected to 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 K a ,  18 K b , and  18 K c  formed in the tape cartridge  10 . Projections of the cartridge discriminating switch elements  102 A,  102 B, and  102 C are determined to correspond to the depths of the detection holes  18 K formed in the bottom wall  18  of the tape cartridge  10 . When a 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 at ON position. When a 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 at OFF position. 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 , based on the 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 to determine the character size and font as well as control the printer unit  50 B as described later. 
     A port PB 7  of the CPU  110  receives signals transmitted from a contact of the jack  50 N. When a plug  115  is inserted into the jack  50 N to supply direct current through an AC power cord  113  into the jack  50 N, power supply from a battery BT to a power unit  114  is cut by means of a break contact of the jack  50 N in order to avoid unnecessary power consumption of the battery BT. At the same time, signals output from the contact of the jack  50 N are input into the port PB 7  of the CPU  110 . The CPU  110  reads the signals to determine whether the main power supplied to the tape printing device  1  is from the AC power cord  113  or the battery BT and subsequently executes the controls according to the requirements. In the embodiment, upon condition that the power is supplied from the AC power cord  113 , the printing speed of the printer unit  50 D is set at the maximum. When the power is supplied from the battery BT, on the other hand, the printing speed of the printer unit  50 B is slowed down to lower the peak of electric current supplied to the printing head  60  and save the power of the battery BT. 
     The eight mega-bit mask ROM  118  connected to an address bus and a data bus of the CPU  110  stores three different fonts of 16×16 dots, 24×24 dots, and 32×32 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 according to the requirements. A 24-bit address bus AD, an 8-bit data bus DA, a chip selecting signal CS, an output enable 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 into an external input-output connector  50 E a  to allow an extension unit  50 E attached to the external input-output connector  50 E a  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 E a  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, marks, and symbols for drawings, maps, chemistry, and mathematics as well as linguistic fonts other than English or Japanese, and character fonts such as Gothic, Ming, and block type faces. This structure allows the user to edit text data in a desirable font. The battery-backed RAM pack in which information is freely written may alternatively be inserted in the extension unit  50 E. The RAM pack stores a greater amount of information than the storage capacity of an internal RAM area of the tape printing device  1  to create a library of text data 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 into 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 and twenty-eight square and circular electrode patterns arranged to surround the dot matrix pattern as shown in FIG.  9 . The area of the dot matrix pattern is designated as a main display element  50 D a  for displaying a print image whereas the area of the square and circular electrode patterns is referred to as an indicator element  50 D b.    
     The main display element  50 D a  is a liquid crystal display panel allowing a display of 16 dots in height by 96 dots in width. In the embodiment, since a character font of 16 dots in height by 16 dots in width is used for data input and editing, a display on the main display element  50 D a  includes six characters by one line. Each letter or character is shown as a positive display, a negative display, or a flash display in the progress of the editing procedure. This allows the user to visually follow the progress of processing with the tape printing device  1 . Although the 16×16 character font is preferable for clearly displaying each character data, another font having the lower resolution, for example, 5×7 character font, may be applied to increase the number of character data which can be displayed on the main display element  50 D a.    
     The display on the main display element  50 D a  is in the dot matrix pattern and controlled arbitrarily. For example, is a layout of current print image may be displayed by a press of a ‘Function’ key on the input unit  50 C shown in FIG.  8 . The layout display is automatically scrolled from the right side to the left side of the main display element  50 D a . This allows the user to check the whole layout of text data. 
     The indicator element  50 D b  surrounding the main display element  50 D a  includes a variety of indicators ‘t’ representing various functions. Some of the indicators ‘t’ corresponding to the functions currently executed by the tape printing device  1  are ON to emit light. The respective functions of the indicators ‘t’ corresponding to the square and circular electrode patterns on the indicator element  50 D b  are printed around the electrode patterns of the display unit  50 D. Available functions include: selection of a character input mode, such as ‘Capital Letter’ or ‘Small Letter’; specification of a printing and editing style, such as ‘Vertical Print’ or ‘Center Line’; and specification of a print format, such as ‘Justification’ or ‘Left Weight’. When a certain function is selected or specified, an indicator ‘t’ corresponding to the function is turned ON to emit light. For example, when the ‘Center Line’ function is set, the indicator ‘t’ corresponding to the ‘Center Line’ lights up. The function ‘EASY’ in the printing and editing style represents automatic specification of a style preset in the tape printing device  1 . 
     The function ‘Line Number’ on the indicator element  50 D b  has four indicators ‘L’ to which digits ‘1’ through ‘4’ are assigned as illustrated in FIG.  9 . While the main display element  50 D a  has the capacity of displaying only one line of text data, the tape printing device  1  can print the maximum of four lines on the tape T. The ‘Line Number’ indicators ‘L’ corresponding to the existing lines of text data are ON to emit light. The procedure of line number display will be described later more in detail. 
     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  and a motor driver  122  for controlling the mechanical constituents as electrical constituents. The printing head  60  is a thermal head having sixty-four heating points arranged in one column at a pitch of {fraction (1/180)} inch, and internally provided with the temperature detection circuit  60 A for detecting the air temperature and the voltage detection circuit  60 B for detecting the supply voltage as described previously. The stepping motor  80  has a known structure for controlling the phase of four-phase driving signals to adjust the rotational angle. A tape feeding distance corresponding to each step of the stepping motor  80  is set equal to {fraction (1/360)} inch by the gear train functioning as a reduction gear mechanism. The stepping motor  80  receives a two-step rotation signal output synchronously with printing of each dot executed by the printing head  60 . The printer unit  50 B thereby executes printing in a printing pitch of 180 dots/inch both in the longitudinal direction of the tape T and the direction of the tape width. 
     The detection switch  99  for detecting the operation of the cutting mechanism is inserted in a common line for connecting the printer controller  120  and the motor driver  122  to the CPU  110  as shown in FIG.  7 . When the cutting mechanism is activated during execution of the printing, the detection switch  99  works to inactivate the printer unit  50 B without delay. Since signals are continuously transmitted from the CPU  110  to the printer controller  120  and the motor driver  122 , the printing procedure is resumed after interruption of the cutting procedure with the cutting mechanism. 
     The power unit  114  incorporated in the tape printing device  1  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  has a port PB 4  allocated to the voltage regulation. 
     The internal ROM of the CPU  110  stores a variety of programs for controlling the peripheral circuits. The internal RAM of the CPU  110  includes a first part designated as a system&#39;s area used for execution of the variety of programs stored in the internal ROM and a second part defined as a user&#39;s area including a text area for editing of text data and a file area for storing contents of the text data. 
     The text area has the capacity of 125 character data of fixed input and stores character codes as well as style data and mode data used for editing the text data. The data in the text area may be supplemented or updated by the data input and editing procedures through the input unit  50 C. The text area on the internal RAM of the CPU  110  may be referred to as a text data buffer. 
     The internal RAM has a file area of 1,500-character capacity while an optionally supplied RAM pack has a file area of 2,000-character capacity. The file area may store and manage 1 through 99 variable-length files according to a file management program stored in the internal ROM. The file management program also provides basic operation environments including registration, load, copy, and delete of a specified file. 
     A general process routine executed by the CPU  110  of the tape printing device  1  of the embodiment is described according to the flowchart of FIG.  10 . The tape printing device  1  has a variety of process modes including a character input mode, a printing information specification mode, and a layout display mode. The tape printing device  1  is set in one of the process modes in response to a press of a corresponding function key on the input unit  50 C. When no function keys are operated but a character key is pressed, character data corresponding to the character key is input. 
     When the program enters the process routine of FIG. 10, the process mode is identified first at step S 200 . When the process mode is not specified, the tape printing device  1  is determined to be in the character input mode and waits for input of character data at step S 210 . Character data corresponding to alphabets and numerals input from the input unit  50 C are directly transferred to a text data buffer whereas those corresponding to ‘kana’ (Japanese alphabets) are sent to the text data buffer after a required conversion of some ‘kana’ to ‘kanji’ (Chinese characters). 
     Character data newly input from the input unit  50 C are added to the end of text data stored in the text data buffer in general procedures, or may be inserted into any desirable position of the existing text data with the aid of cursor positioning. Alternatively, the newly input character data may be over-written to replace the existing text data. 
     The text data buffer has the capacity of 125 character data. When text data over the 125-character capacity are input from the input unit  50 C, the CPU  110  executes an overflow process at step S 220 . In the case of ‘kana’ input, the overflow process is executed after conversion to ‘kanji’. The overflow process eliminates character data exceeding the 125-character limit from the end of text data stored in the text data buffer in either case when input character data are added to the end of the text data or when input character data are inserted at a desirable position of the text data. 
     After the overflow process at step S 220 , the program goes to step S 230  at which text data finally settled are displayed on the display unit  50 D. As described previously, text data of up to four lines can be printed on the tape T whereas the display unit  50 D has the capacity of displaying only six character data by one line. In this embodiment, each character data input at step S 210  is managed as 16-bit information. Printing information representing a line number and other attribute data also occupies one-character space (=16 bits) in the text data buffer. The 16-bit printing information consists of a flag for identifying a line number (2 bits), data representing the total number of lines (2 bits is sufficient for the maximum of four lines), face data (3 bits for 7 faces), font data (5 bits) including distinction between an internal font and an external fonts, and line spacing and inter-character spacing data (4 bits). 
     The process of displaying text data stored in the text data buffer at step S 230  consists of several steps shown in the flowchart of FIG.  11 . At step S 400 , the ‘Line Number’ indicators ‘L’ on the indicator element  50 D b  corresponding to the existing lines of text data are turned ON to emit light. One of the ‘Line Number’ indicators ‘L’ corresponding to a line where the cursor is currently positioned is then shown by flashing at step S 410 . The program subsequently goes to step S 420  at which text data of the cursor-positioned line are then displayed on the main display element  50 D a  as the dot matrix pattern. 
     The lighting and flashing process of the ‘Line Number’ indicators on the indicator element  50 D b  allows the user to check the total number of existing lines of text data to be edited and the position of the cursor. FIGS. 12A and 12B show examples of the lighting and flashing process of the ‘Line Number’ indicators executed at steps S 400  and S 410 . When three lines of text data are edited for printing as shown in FIG. 12A, the liquid-crystal ‘Line Number’ indicators ‘L’ having the digits ‘1’, ‘2’, and ‘3’ are turned ON to emit light. The ‘Line Number’ indicator ‘L’ having the digit ‘2’ flashes to show that the cursor is positioned on the second line and that text data of the second line is currently displayed on the main display element  50 D a . The term ‘flash’ means switching ON and OFF at predetermined short intervals. In the example of FIG. 12B, four lines of text data are edited for printing and the cursor is positioned on the first line. All the ‘Line Number’ indicators ‘L’ having the digits ‘1’ through ‘4’ are turned ON to emit light whereas the ‘Line Number’ indicator ‘L’ having the digit ‘1’ flashes, accordingly. After the text data display process at step S 230 , the program goes to ‘NEXT’ and exits from the routine. 
     The printing information specification mode may be set for each paragraph. The term ‘paragraph’ denotes each block of text data divided along the length of the tape T. In one example, text data printed on the tape T to represent a title applied onto the spine of a video tape include a first paragraph for picture data or icon of one line, a second paragraph for character data of one line representing the name of the film, and a third paragraph for character data of two lines representing the names of the director and leading actors and actresses. 
     When the printing information specification mode is selected at step S 200 , the program goes to step S 240  at which required printing information is specified and either ‘AUTO’ mode or ‘MANUAL’ mode is selected for plural-line printing. The required printing information includes a total number of lines printed on the tape T, enhancement data (for example, bold, italics, underlined, outline type, and highlighted), inter-character spacing data (narrow, standard, wide), line spacing data (narrow, standard, wide), and font data for distinguishing between an internal font and an external ROM font. Each printing information is specified by selecting a desirable one out of a plurality of choices previously prepared. For example, the total number of lines to be printed is selected from the choices ‘1’, ‘2’, ‘3’, and ‘4’ since text data of up to four lines can be printed on the tape T in the embodiment. For plural-line printing, either the ‘AUTO’ mode or the ‘MANUAL’ mode is selected. The plurality of choices are successively highlighted on the display unit  50 D through operation of the cursor keys and space bars on the input unit  50 C. The user presses the ‘Return’ key on the input unit  50 C to settle each printing information selected. In this embodiment, ‘style’ information represents information applied to the whole paragraph, such as the total number of lines to be printed and selection of horizontal or vertical print, whereas ‘mode’ information denotes the other specified information, such as inter-character spacing data. 
     When plural-line printing is specified, the program goes to step S 250  at which a desirable font combination is determined. The tape printing device  1  of the embodiment has three different font data of 16×16 dots, 24×24 dots, and 32×32 dots as basic fonts stored in the mask ROM  118 . The non-overlapped dots in each font are expandable by two times both in height and width. There are accordingly seven possible combinations of printable dot numbers or fonts including the maximum font of 64×64 dots. When text data are edited and printed in a plurality of lines, specification of the font applied to the text data on each line is required in addition to input of character data printed on the line. The seven printable dot number combinations correspond to ‘Compress’, ‘Expand’, ‘P’, ‘S’, ‘M’, ‘L’, and ‘G’ with the indicators ‘t’ on the indicator element  50 D b  as shown in FIG.  9 . The indicator ‘t’ corresponding to the selected printable dot number combination lights up to inform the user. 
     The process executed at steps S 240  and S 250  in the printing information specification mode specifies fundamental information significantly affecting the results of printing on the tape T. The user is hence required to specify the printing information and the font while roughly estimating the results of printing. The tape printing device  1  of the embodiment further executes the processing described below in order to simplify the operations in the printing information specification mode and improve the printing quality. 
     FIG. 13 is a flowchart showing the process of specifying ‘style’ information applied to the whole paragraph with a default. The ‘style’ information specified here is selection of either ‘Vertical Print’ or ‘Horizontal Print’. For selection of either ‘Vertical Print’ or ‘Horizontal Print’, it is first determined whether a default has already been set in a specific area of the RAM at step S 500 . Upon condition that power supply to the tape printing device  1  has just started and no default has been set in the RAM, a default stored in the ROM as non-volatile data, in this embodiment, selection of ‘Horizontal Print’, is read from the ROM at step S 510 . The default is then stored in the specific area of the RAM at step S 520 . 
     When it is determined that the default has already been set in the RAM at step S 500  or after the processing of step S 520  is completed, the program proceeds to step S 530  at which the default is displayed on the main display element  50 D a  of the display unit  50 D. During the display, the user may change the default according to the requirements. 
     The default of the ‘style’ information once set in the specific area of the RAM is applied to the subsequent paragraphs unless the user intentionally inputs data to change the default. This prevents the different writing styles, ‘vertical Print’ and ‘Horizontal Print’ from being mixed up unintentionally on the tape T. Although the user can arbitrarily change the ‘style’ of printing text data on the tape T, confusing arrangement of ‘Vertical Print’ and ‘Horizontal Print’ is generally not preferred. 
     Other than the default used for the simplified specification of the ‘style’ information, the tape printing device  1  of the embodiment has a plurality of defaults called application forms where all the ‘style’ information and the ‘mode’ information have been set in advance. The user can specify the ‘style’ information including the total number of lines to be printed and selection of ‘Vertical Print’ or ‘Horizontal Print’ as well as the ‘mode’ information including inter-character spacing data and fancy type data by simply selecting a desired default among the plurality of application forms. FIG. 14 is a flowchart showing a routine of selecting a desired application form, which is executed at a start of the printing information specification mode. At step S 600 , it is determined whether the ‘style’ information and ‘mode’ information are specified automatically or manually, based on operation of a specific key on the input unit  50 C. When the manual specification is selected, the program enters the ‘Manual’ mode where the processing of steps S 240  and S 250  are successively executed. The tape printing device  1  waits for an input of the ‘style’ information by the user at step S 610  and sets the ‘style’ information according to the input at step S 620 . In a similar manner, the tape printing device  1  waits for an input of the ‘mode’ information by the user at step S 630  and sets the ‘mode’ information according to the input at step S 640 . The program then exits from the routine. 
     When the easy specification is selected at step S 600 , the program enters the ‘EASY’ mode, which as set forth above, in the printing and editing style represents automatic specification of a style preset in the tape printing device  1 . At step S 650 , the tape printing device  1  displays titles of application forms having specified defaults on the display unit  50 D and waits for selection of a desired application form out of the plural choices. There are eight application forms preset in the embodiment, which have the titles of ‘VHS: Horizontal’, ‘VHS: Vertical’, ‘VHS-C’, ‘8 mm Video’, ‘Cassette Tape’, ‘Name &amp; Address’, ‘Name Plate’, and ‘Identification Tag’ (‘VHS’, ‘VHS-C’, and ‘8 mm Video’ are trade names). FIGS. 15A through 22A show the titles and the specified defaults of ‘style’ information and ‘mode’ information whereas FIGS. 15B through 22B show examples of printing based on the defaults. These application forms give only eight combinations of the ‘style’ and ‘mode’ defaults, and the user can arbitrarily change the defaults specified by the selected application form as described later. As shown in FIGS. 15A through 22A, each application form only suggests a position suitable for picture data or icon, a position suitable for standard character data, and a position suitable for data of the date and time by specific display on the display unit  50 D. The tape printing device  1  accepts an input of text data in an arbitrary form different from the suggestion other than an input of text data in the suggested form. 
     After the user selects a desired title of application form at step S 650 , the program goes to step S 660  at which the ‘style’ and ‘mode’ defaults are set corresponding to the selected application form. At step S 670 , it is determined whether modification of the defaults is required. When any modification is required, the program goes to step S 610  to change the defaults. When no modification is required, on the contrary, the program exits from the routine. 
     When the layout display mode is selected at step S 200 , the program goes to step S 260  at which the CPU  110  reads an output of the cartridge discriminating switch  102 , which represents the type of tape cartridge  10  set in the tape printing device  1 , and more specifically, the printable width of the tape T. After the identification of the tape width, the program goes to step S 270  to display text data in a specific layout corresponding to the specified printing information and font combination. When a tape cartridge  10  having the tape T of appropriate width is set in the tape printing device  1 , text data are shown in white against the tape T shown in black on the main display element  50 D a . Upon condition that no tape T is set in the tape printing device  1 , text data (with a frame line according to the requirements) are shown in black while the tape T is not displayed at all. This inverted display of text data distinctively informs the user of no setting of the tape T. 
     When the width of the tape T is insufficient for the selected ‘style’ and ‘mode’ information, a portion out of the tape width is highlighted. An acoustic or visual alarm may also inform the user of non-tape setting or inappropriate tape setting. After the layout display process at step S 270 , the program goes to step S 230  to resume the display of text data on the display unit  50 D. 
     When a print mode is selected at step S 200 , the program goes to step S 280  at which the CPU  110  reads detection signals output from the cartridge discriminating switch  102 . At step S 290 , the CPU  110  determines the width of the tape T set in the tape printing device  1  based on the detection signals from the cartridge discriminating switch  102 , and expands a dot pattern of each line according to the tape width and the relative character size of each line by referring to a font map previously stored in the internal ROM. 
     The dot pattern expansion process of step S 290  includes specifying a suitable font used for printing each line, successively reading character codes of the specified font corresponding to the text data from mask ROM  118 , and expanding each character code to a dot pattern. After completing the dot pattern expansion at step S 290 , the program goes to step S 300  to execute printing. In concrete procedures, the CPU  110  prepares 64-bit serial data by extracting the dot pattern by every column, and transfers the serial data to the printer unit  50 B. 
     Text data stored in the text data buffer are then printed in either ‘Auto’ mode or ‘Manual’ mode. In ‘Manual’ mode, text data stored in the test data buffer are printed according to the number of lines previously specified. After plural-line printing, for example, two-line printing, is specified and text data are input for two lines, text data on the second line may be eliminated according to the requirements. On condition that the user eliminates text data for the second line, text data for only the first line should be printed. In ‘Auto’ mode, when no text data exists on the second line, text data of only the first line are expanded to dot patterns and printed with a large font. When text data exist on both the first and the second lines, on the other hand, a smaller font is selected for printing text data of the two lines. In ‘Manual’ mode, even when no text data exists on the second line, text data of the first line is printed with a font selected for the two-line printing. This printing procedure is applied to any plural-line printing such as three-line printing or four-line printing as well as two-line printing described above. 
     In the tape printing device  1  of the embodiment, text data input from the input unit  50 C can be stored as a file in the internal RAM having a 1,500 character capacity and in the extension unit  50 E having a 2,000 character capacity. When the read/write mode is selected at step S 200 , the program goes to step S 310  at which it is determined whether a file is accessible. In the write mode, file accessibility implies existence of a vacant space to allow a new file to be stored in the internal RAM or the extension unit  50 E. In the read mode, file accessibility denotes existence of a previously recorded file. When the file is not accessible at step S 310 , the program goes to step S 230  to resume the display of text data on the display unit  50 D after displaying an error message ‘Out of Access’. When the file is accessible at step S 310 , on the contrary, the program goes to step S 320  at which text data currently stored in the text data buffer are recorded as a file in the write mode, or text data previously recorded are read to the text data buffer in the read mode. 
     When text data existing in the text data buffer are recorded as a file, attribute information of the text data including both the ‘mode’ information and ‘style’ information is recorded together. The attribute information stored with text data includes data representing the number of printing lines, font data, inter-character spacing data, line spacing data, and enhancement data (for example, bold, outline face, underlined, italics). In the read mode, text data are read with the attribute information to the text data buffer. When text data input from the input unit  50 C already exist in the text data buffer, read-out text data are added to the end of the existing text data in the text data buffer. When the attribute information of the read-out text data is different from that of the existing text data, a discrimination mark is given to the read-out text data at step S 330 . 
     The discrimination mark designated as, for example, a rightward closed triangle includes information such as enhancement data and the inter-character spacing data. The discrimination mark assigns the attribute information previously recorded in the existing file to the text data, which are read out to be linked with the existing text data in the text data buffer having different attribute information. As a result, the read-out text data with the discrimination mark are printed according to the attribute information recorded in the existing file while the newly input text data are printed according to the different attribute information. When a new paragraph of text data is input after the read-out text data, the attribute information of the read-out text data set in the discrimination mark does not affect attribute of the newly input text data. When it is preferable to change the attribute of the read-out text data to be identical with the attribute of text data input from the input unit  50 C, the discrimination mark is to be eliminated. 
     As a typical example of the file reading and writing process executed at step S 320  in the flowchart of FIG. 10, a process of registering an abbreviation, a process of reading the registered abbreviation, and a process of deleting the registered abbreviation are shown in FIGS. 23,  24 , and  25 , respectively. 
     The tape printing device  1  of this embodiment has a registration area which can store nine abbreviations of up to 16 letters, where each abbreviation may represent text data of up to 40 letters. The user can set the abbreviation registration mode by pressing the power switch  50 J simultaneously with the ‘Function’ key on the input unit  50 C as shown in FIG.  23 . The existing abbreviations are then read out of the registration area. The user presses the rightward cursor key to find a vacant space in the registration area and inputs the whole text data to be registered and subsequently an abbreviation representing the text data. 
     When the user inputs an abbreviation and executes the required operation for conversion shown in FIG. 24, the original text data corresponding to the abbreviation is read out of the registration area and displayed on the display unit  50 D. 
     The abbreviation previously registered in the registration area can be deleted easily by setting the tape printing device  1  in the abbreviation registration mode, reading out an abbreviation to be deleted, and executing the required operation shown in FIG.  25 . Deletion of an abbreviation is implemented simply by overwriting blanks on the abbreviation to be deleted and the corresponding text data. The structure of the embodiment allows registration and deletion of abbreviations to be implemented by similar operations, thus reducing the time and labor required for the registration and deletion procedures. Upon condition that no abbreviation has been registered corresponding to input text data, even when the user executes the required operation for conversion, no abbreviation but only the input text data is displayed on the display unit  50 D as shown in FIG.  25 . 
     Although operations of the tape printing device  1  of the embodiment in typical modes are described above, the tape printing device  1  may also be used in other modes which are not explained here. 
     The tape printing device  1  of the embodiment thus constructed has the following advantages over the conventional tape printing devices. The display unit  50 D of the embodiment includes the indicator element  50 D b  and the main display element  50 D a  for displaying only one line of print image as described above. The display unit  50 D is approximately a quarter in size of the display unit of the conventional tape printing device used for editing text data of up to four lines. 
     The tape printing device  1  of the embodiment, however, has the comparable functions for editing text data on the display unit  50 D to those of the conventional tape printing device having the larger display unit. The indicator element  50 D b  of the embodiment has the four ‘Line Number’ indicators. The ‘Line Number’ indicators on the indicator element  50 D b  corresponding to the existing lines of text data are turned ON to emit light whereas one of the ‘Line Number’ indicators corresponding to a line currently displayed on the main display element  50 D a  and edited is distinguished by flashing. This lighting and flashing operation on the indicator element  50 D b  gives sufficient information on the line numbers required for editing procedures. 
     It is generally not required to display all the lines of text data simultaneously for editing the plural lines of text data. The structure of the embodiment allows the user to check the total number of lines of text data to be edited as well as the line number currently displayed on the main display element  50 D a  by the indicators on the indicator element  40 D b.    
     Although, the small-sized display unit  50 D can display only one line of text data, sufficient information required for editing a plural lines of text data is given to the user. 
     The structure of the embodiment may be changed or modified according to the requirements. Although the main display element  50 D a  of the embodiment has the capacity of displaying only one line of text data, it may be modified according to the layout of the whole tape printing device to allow two or three lines of text data to be displayed. In the latter case, the indicators on the indicator element  50 D b  also effectively inform the user of the total number of existing lines to be edited and the line number currently displayed on the main display element  50 D a  for editing procedures. In another application, the line number currently displayed and edited may be displayed before the discrimination mark. The maximum column number of text data currently edited and the column number where the cursor is positioned may also be displayed in a similar manner. 
     In the embodiment, text data are printed on the tape T having the adhesive rear face. The tape printing device of the embodiment may, however, be applied to other tapes, such as tapes having the adhesive layer separately applied thereon, laminate tapes having a transparent sheet for protecting the print applied thereon, and tapes specifically used for print with transferable ink. 
     A tape printing device  700  is described as a second embodiment according to the invention. The tape printing device  700  of the second embodiment has a display unit  750 D shown in FIG. 26, which is different from the display unit  50 D of the tape printing device  1  of the first embodiment. The display unit  750 D includes a main display element  750 D a  having the capacity of displaying four lines of text data, that is, all the printable lines, and an indicator element  750 D b  surrounding the main display element  750 D a . Indicators ‘t’ on the indicator element  750 D b  respectively correspond characters and abbreviations printed thereon, which represent various functions and are different from those of the first embodiment, and emit light or flash in the same manner as the first embodiment. 
     The characters and abbreviations printed on the indicator element  750 D b  include: those representing the number of lines to be edited (Auto, 1, 2, 3, 4); those representing enhancement of printed letters (Border, Shade, etc.); those representing specification of serifs and capital letters (Rmn, SCAN, Caps), and one representing vertical print (Vert); and those representing the font size (Font Size: 1, 2, 3, 4, 5, 6, Wide). 
     FIG. 27 is a flowchart showing a display control routine executed in the second embodiment. When the program enters the routines, the CPU  110  first reads a specified number of lines ‘m’ at step S 800 . Headers of the first line through the line currently edited are displayed on the second column from the right on the main display element  750 D a  at step S 805 , and the cursor is flashed on the right-most column of the currently edited line at step S 810 . FIG. 28A shows a display on the main display element  750 D a  when character data ‘A, B, C’ have already been input on the first of the four printing lines and editing starts on the second line. The tape printing device  700  then waits for an input of text data at step S 815 . The CPU  110  then identifies a key input from the input unit  50 C at step S 820 . When one of the cursor keys is operated, the program goes to step S 830  at which a shifting process shown in FIG. 29 is executed to shift data displayed on the main display element  750 D a . Since the cursor position is fixed on the right-most column on the main display element  750 D a , it is first determined whether any character data exists on the right or the left of the cursor position at step S 831  in the flowchart of FIG.  29 . When any character data exists on the right or the left of the cursor, the program goes to step S 832  at which whether the header of each line, that is, line number data LDP, which moves with text data, is positioned on the left-most column on the main display element  750 D a . When the line number data LDP is not positioned on the left-most column, the program proceeds to step S 833  at which input text data CDP are displayed with the line number data LDP while the line number data LDP and the existing text data CDP are moved leftward in response to each input of text data CDP. FIG. 28B shows a display on the main display element  750 D a  when character data ‘defg’ are input on the second line. 
     When the line number data LDP is positioned on the left-most column on the main display element  750 D a , on the contrary, the program goes to step S 834  at which the input text data CDP are displayed on the second column from the left through the right-most column (that is, the column where the cursor is positioned) on the main display element  750 D a  while the line number data LDP is fixed on the left-most column. FIG. 28C shows a display on the main display element  750 D a  when character data ‘hijklm’ are further input after ‘defg’ on the second line and the head of the text data ‘d’ is eliminated from the display area. 
     When any of character keys is operated on the input unit  50 C at step S 820  in the flowchart of FIG. 27, the program proceeds to step S 840  at which character data input on the cursor position is displayed and to step S 841  at which the whole display on the main display element  750 D a  is shifted leftward by one character space. The method of display is varied according to the position of the line number data LDP on the main display element  750 D a  in the same manner as the processing of steps S 832  through S 834  described above. When ‘Delete’ key is operated on the input unit  50 C at step S 820 , the program goes to step S 850  at which character data at the cursor position is deleted and to step S 852  at which the whole display on the main display element  750 D a  is shifted rightward by one character space. In this case, the method of display is also varied according to the position of the line number data LDP on the main display element  750 D a  in the same manner as the processing of steps S 832  through S 834  described above. 
     When the downward cursor key is operated upon condition that the cursor is positioned on the second line (see FIG.  28 C), another line, that is, the third line, to be edited appears on the main display element  750 D a  while the cursor position is unchanged as shown in FIG.  28 D. When text data consists of five or a greater number of lines, the fifth or the following line appears on the main display element  750 D a  in response to an operation of the downward cursor key whereas the first or the corresponding line disappears from the main display element  750 D a.    
     While the total number of lines and the line number currently displayed and edited are indicated on the left of the main display element  50 D a  in the first embodiment, the line number is displayed with text data on the main display element  750 D a  in the structure of the second embodiment. The structure of the second embodiment distinctly informs the user of the line number currently edited. The line number data is always positioned on the head of the text data and fixed at the left-most column after the line number data reaches the left-most column on the main display element  750 D a . This allows the user to check the column number easily. The display unit  750 D of the second embodiment has the capacity of displaying the maximum of four lines, thus allowing text data to be edited readily. 
     A tape printing device  900  is described as a third embodiment according to the invention. The tape printing device  900  of the third embodiment has the same structure as that of the tape printing device  700  of the second embodiment. FIG. 30 is a plan view showing the appearance of the tape printing device  900 , and FIG. 31 is a block diagram showing electric constituents of the tape printing device  900 . As illustrated in FIG. 30, the tape printing device  900  is provided with a cover  910  and a tape cartridge holder unit  911  under the cover  910  like the tape printing device  1  of the first embodiment. A tape  912  is drawn out of a tape cartridge for printing, discharged from a tape outlet on the left side wall of the device  900 , and cut in response to an operation of a cut button  913 . 
     The tape printing device  900  has a keyboard unit  914  on which various character keys and function keys are mounted. Specific functions are assigned to several character keys which are effective only when the ‘Function’ key is pressed. For example, the digit key ‘1’ has the function ‘Meas’ which shows and changes the unit of length of the tape  912 . A display unit  915  of the tape printing device  900 , which is identical with the display unit  750 D of the second embodiment, is a black and white liquid-crystal display having the capacity of displaying the maximum of four lines. 
     Referring to the block diagram of FIG. 31, the tape printing device  900  includes an input unit  92   b , a control unit  930 , and an output unit  940  in its electric configuration. The control unit  930  receives data from the input unit  920 , executes the required processing, and outputs the results of the processing to the output unit  940 , which displays or prints the outputs transmitted from the control unit  930 . 
     The input unit  920  includes a key input unit  921  receiving various signals sent from the keyboard unit  914  shown in FIG. 30, and a tape width detection sensor  922 . The key input unit  921  outputs various character code data and control data to the control unit  930 . The tape width detection sensor  922  detects the width of the tape set in the tape printing device  900  and outputs the tape width information to the control unit  930 . 
     The output unit  940  includes a thermal printing head  941 , a head-driving element  942  for driving the printing head  941 , a tape-feeding motor  943  for rotating a platen to feed the tape, a motor-driving element  944  for driving the tape-feeding motor  943 , the liquid-crystal display unit  915 , and a display-driving circuit  945  for actuating the liquid-crystal display unit  915 . 
     The control unit  520  is typically constructed as a microcomputer and includes a CPU  931 , a ROM  932 , a RAM  933 , a character generator ROM (CG-ROM)  934 , an input interface element  935 , and an output interface element  936 , which are connected to one another via a system bus. Various operation programs and fixed data are stored in the ROM  932 . 
     The RAM  933  is used as a working memory and stores data input by the user. The CG-ROM  934  stores dot patterns of characters and symbols prepared for the tape printing device  900 , and outputs a corresponding dot pattern in response to an input of code data representing a character or symbol. Separate CG-ROMs may be used for display and printing. The input interface element  935  works as an interface between the input unit  920  and the control unit  930  whereas the output interface element  936  functions as an interface between the control unit  930  and the output unit  940 . 
     The CPU  931  receives input signals from the input unit  920  and data stored in the ROM  932  or the RAM  933 , and executes the required processing based on the operation programs stored in the ROM  932  using the RAM  933  as the working area. The progress or result of the processing is displayed on the display unit  915  or printed on the tape  912 . 
     FIG. 32 is a flowchart showing a process routine executed by the tape printing device  900  of the third embodiment. This process routine changes the unit of length of the tape on the display unit  915 . The tape printing device  900  has a function of changing the unit of length applied to display of the tape length, which is calculated based on the number of input character data and specification of font and character size. 
     When the program enters the routine, the tape printing device  900  waits for a key input at step S 1011 . When the user operates any key on the keyboard unit  914 , it is determined whether a ‘Unit Change’ key function is activated at step S 1012 . Although the ‘Unit Change’ key function is realized by pressing the ‘Function’ key and the digit key ‘1’ in this embodiment, a separate ‘Unit Change’ key may be mounted on the keyboard unit  914 . When the key input is not the ‘Unit Change’ key function at step S 1012 , the program goes to step S 1013  to display character data corresponding to the input character key or execute required processing according to the input function key. 
     When the ‘Unit Change’ key function is activated at step S 1012 , the program goes to step S 1014  at which a flag FLAG is set equal to zero and to step S 1015  at which the tape printing device  900  displays a menu to request the user to select the unit of length. In this embodiment, ‘cm’ and ‘inch’ are shown as possible choices on the liquid-crystal display unit  915  as shown in FIG. 33, where one choice ‘cm’ is highlighted as a default. The tape printing device  900  again waits for a key input at step S 1016  after the display of the menu. When the ‘Return’ key, which functions as ‘Select’ key, is pressed at step S 1017 , the highlighted choice ‘cm’ is fixed as the unit of length and the program returns to step S 1011  to wait for another key input. 
     When the leftward cursor key is pressed while the menu is displayed on the display unit  915  at step S 1018 , the program goes to step S 1019  at which the flag FLAG is set equal to zero and to step S 1020  at which the choice ‘cm’ is highlighted on the display unit  915  as shown in FIG.  33 . When the rightward cursor key is pressed while the menu is displayed on the display unit  915  at step S 1021 , on the other hand, the program goes to step S 1022  at which the flag FLAG is set equal to one and to step S 1023  at which the choice ‘inch’ is highlighted on the display unit  915  as shown in FIG.  34 . The program then returns to step S 1016  to wait for another key input. 
     When the ‘Print’ key is operated at step S 1011 , the program enters a printing process routine, which is executed at step S 1013  in the flowchart of FIG.  32  and shown in the flowchart of FIG.  35 . In response to an operation of the ‘Print’ key, it is determined whether the flag FLAG is equal to zero at step S 1032 . The flag FLAG=0 represents selection of ‘cm’ in metric system as the unit whereas FLAG=1 denotes selection of ‘inch’ in inch-yard system. When FLAG=0 at step S 1032 , the program goes to step S 1033  at which the length of the tape is shown by ‘cm’. When FLAG=1 at step S 1032 , on the contrary, the program goes to step S 1034  at which the tape length is shown by ‘inch’. 
     FIG. 36 shows an exemplified display by ‘cm’ and FIG. 37 shows one by ‘inch’. The CPU  931  calculates required blanks based on the number of input character data and specification of the font and character size, determines a required tape length in the selected unit or dot number, and displays the tape length on the liquid-crystal display unit  915 . For the display by ‘cm’, millimeter is used for the length below ‘1 cm’. For the display by ‘inch’, fractions like ½ and ⅜ are used for the length below ‘1 inch’. These values are determined by referring to a conversion table previously stored in the ROM  932 . The conversion table is used for the conversion between the dot number, ‘cm’ and ‘inch’ as shown in FIG.  38 . After the processing at step S 1033  or S 1034 , the program goes to step S 1035  at which the tape printing device  900  executes the printing operation to print text data on the tape. The program then goes to ‘END’ to exit from the routine. 
     The structure of the embodiment allows the user to readily check and determine the length of the tape  912  required for printing by a desired unit. The unit of length is easily changed between a plural choices, which are displayed on the display unit  915 . 
     Although the ‘Unit Change’ key function is activated by the certain key operation in the embodiment, the unit of length may be changed by a key pressed simultaneously with the ‘Power’ button as shown in the flowchart of FIG.  39 . When the power is turned ON at step S 1040 , the control unit  930  determines whether any key is pressed at step S 1041 . When any key is pressed, the program successively goes to steps S 1042  and S 1044  to determine whether the key is ‘M’ or ‘I’. When the key ‘M’ representing the metric system is pressed, the program goes to step S 1043  to set the flag FLAG equal to zero. When the key ‘I’ representing the inch-yard system is pressed, the program goes to step S 1045  to set the flag FLAG equal to one. The program then goes to ‘END’ to exit from the routine. 
     This structure sets the flag FLAG according to the key pressed simultaneously with the ‘Power’ button. In this structure, the length of the tape is also displayed by either ‘cm’ or ‘inch’ in the printing process shown in FIG.  35 . For change of the unit, after the input text data are stored in a file and the tape printing device  900  is once turned OFF, the power is turned ON again with the press of either the ‘M’ or ‘I’ key. 
     This structure allows a desired unit of length to be set only by pressing the ‘I’ or ‘M’ key representing each measuring unit when the device  900  is switched ON. 
     There may be many modifications, alterations, and changes without departing from the scope or spirit of essential characteristics of the invention. It is thus clearly understood that the above embodiments are only illustrative and not restrictive in any sense. The scope and spirit of the present invention are limited only by the terms of the appended claims.