Patent Publication Number: US-8118505-B2

Title: Label printer with a label peeling mechanism and a control method for the same

Description:
RELATED APPLICATION 
     This application is a continuation of, and claims priority under 35 U.S.C. §120 on, U.S. application Ser. No. 11/181,283, filed Jul. 14, 2005, the contents of which are incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field of Invention 
     The present invention relates generally to a label printer for printing labels affixed to a web liner, and relates more particularly to a label printer having a label peeling mechanism for peeling labels from a web liner, and to a control method for this label printer. 
     2. Description of Related Art 
     Label printers are used for printing labels with such information as a product name, price, and product code (barcode). The labels are thereafter affixed to products. 
     In the back room of a store, for example, the label printer is typically placed on a work-table to print labels, and as the labels are affixed to the products as they are printed and peeled from a web liner. Label printers are also used to batch print multiple labels, which are then taken to a separate location, such as the warehouse where the products are stored, and the labels are applied to the individual products. 
     In the former application, a label peeling mechanism is preferably used to automatically peel the labels one by one from the web liner as the labels are printed. 
     A label printer with such a label peeling mechanism is taught in Japanese Unexamined Patent Appl. Pub. H8-295323 (corresponding to U.S. Pat. No. 5,980,138), for example. This label printer stores a roll of label paper having labels affixed at a constant interval to the surface of a continuous web liner in a storage compartment inside the printer. The leading end of the roll paper is fed between the print head and platen roller so that the roll paper can be advanced and printed, and is then passed outside of the printer. The web liner (or simply web) held between and conveyed by the drive platen roller and a peeling roller (pinch roller) that rotates following the platen roller. 
     This printer can be set to operate in a non-peeling mode (continuous printing mode) in which the label peeling mechanism is not used or a peeling mode in which the label peeling mechanism is used. The non-peeling mode is set by passing the leading end of the roll paper (labels affixed to a web liner) through the label discharge opening (label dispenser opening) of the label peeling mechanism, and enables printing and outputting multiple labels intact on the web. The peeling mode is set by threading the leading end of the roll paper around a curved portion of the label peeling mechanism before passing the end outside the printer, thus enabling the label peeling mechanism to peel and dispense the printed labels one by one from the web as the labels are printed. 
     Whether the label peeling mechanism is used or not is selected by the operator opening the peeler cover, which is part of the peeling mechanism, and passing or not passing the leading end of the roll paper out through the label discharge opening (label dispenser opening). 
     To set the label paper  58  (roll paper having labels affixed at a constant interval to a web liner  59 ) to use the peeling mode as shown in  FIG. 12A , a number of labels must first be peeled from the leading end of the label paper  58  so that only the web liner  59  is left. When the label peeling mechanism is used, the web liner  59  is held and conveyed between the platen roller  50  and peeling roller  50   a  after the labels are peeled. This is because the paper transportation load is high around the web-bending guide  53  of the label peeling mechanism, and if thick paper, such as label paper  58  having the labels intact on the web liner  59 , is fed between the platen roller  50  and peeling roller  50   a , the transportation load is even greater and feeding the label paper may not be possible. In addition, the labels tend to separate from the web and stick to the platen roller  50  or peeling roller  50   a , and paper jams thus occur easily. As a result, a number of labels must be removed from the leading end of the label paper  58  and only the web liner  59  is fed between the platen roller  50  and peeling roller  50   a.    
     The label peeling mechanism also has a web-bending guide  53  positioned in the transportation path whereby the label paper  58  is conveyed between the platen roller  50  and thermal print head  51  in conjunction with clockwise rotation of the platen roller  50 . The web-bending guide  53  of the label peeling mechanism causes the label paper  58  to curve through an acute angle to the back (non-label) side of the web. When the label paper  58  passes over the web-bending guide  53  of this label peeling mechanism, the first label  60   a  adhesively affixed to the front surface of the web liner  59  is unable to follow the transportation path of the web liner  59  and is thus disengaged from the web liner  59 . The peeled label  60   a  is then discharged externally to the printer from the label discharge slot  55 . The remaining web liner  59  follows a different transportation path, and the label  60   a  and web liner  59  are thus separated. This is shown in  FIG. 12A . 
     When this label peeling mechanism is used to peel labels  60   a  from the web liner  59  and dispense the labels  60   a  from the label discharge slot  55 , the labels  60   a  are gradually peeled from the leading end thereof in the paper transportation direction by routing the web liner  59  to which the labels  60   a  are affixed around the web-bending guide  53 , and transporting the web liner  59  pauses at a position where a slight portion of the trailing end of the label  60   a  remains attached to the web liner  59 . This is because the label  60   a  will fall out from the label discharge slot  55  if the label  60   a  is completely separated from the web liner  59 . A peeled label detection sensor  56  can detect the peeled label  60   a  is in the label discharge slot  55 . 
     When the label paper  58  passes a label detection sensor  57 , the label detection sensor  57  detects the trailing end of the first label  60   a  and the leading end of the next label  60   b , and the positions of the labels  60   a ,  60   b  can thus be known. The label  60   a  can thus be stopped at the appropriate position. This operation results in the first label  60   a  being discharged without being printed. 
     As shown in  FIG. 12B , the label printer then waits for the discharged label  60   a  to be removed from the web liner  59 . The peeled label detection sensor  56  detects when the operator manually removes the label  60   a , thus triggering the platen roller  50  to rotate counterclockwise as shown in  FIG. 12C  to reverse the label paper  58  and position the leading end of the next label  60   b  on the web liner  59  relative to the thermal print head  51  for printing. Note that the position shown in  FIG. 12C  is called the “label indexing position.” 
     The label paper  58  is reversed because advancing the label paper  58  to where the operator can remove the discharged label (to the position shown in  FIG. 12A , referred to as the “label peeling position”) positions the leading end of the next label  60   b  beyond (that is, downstream of) the printing position of the thermal print head  51 . If printing then proceeds from this position, the next label  60   b  will be printed from some middle part of the label. By reversing the label paper  58 , however, printing can start from the leading end of the next label  60   b  (“label indexing position”) when the print data is received. 
     Whether using the label printer in the peeling mode or using the label printer in the non-peeling mode, the label printer must be mechanically reinitialized (reset) when a new roll is loaded after the last label on a roll is printed and the roll has ended. This involves positioning the leading end of the first label on the new roll next to the printing position of the print head (label indexing process) so that printing can start from the leading end of the label (“label indexing position”). 
     More particularly, the paper transportation mechanism is driven by a motor to advance the roll paper relative to the print head in this label indexing process. Because the label printer described above is a thermal printer, the roll paper is held between the print head and platen roller, and the platen roller is driven rotationally to convey the roll paper. The platen roller is positioned on the main cover side of the printer, and the print head is positioned inside the printer case. 
     To replace the roll paper the main cover is opened, the platen roller is released from the print head, and the roll paper is passed between the platen roller and print head. When the main cover is then closed, the roll paper is held between the platen roller and print head, and the roll paper can be transported. The label indexing process must therefore be executed after confirming that the main cover of the label printer is closed. 
     However, the label printer cannot automatically execute the label indexing process and start printing as soon as print data is received just because the main cover is detected to be in the closed position. This is because in a label printer with an on-board label peeling mechanism the peeling mechanism must be opened after closing the main cover, the roll paper must be loaded into the transportation path used for the peeling mode or the non-peeling mode as desired and the peeling mechanism is then closed to set the roll paper in the desired transportation path. Furthermore, because the operator loads the roll paper, the operator could close the peeling mechanism with the paper accidentally loaded into the wrong transportation path. If the mechanical reset process and printing start with the roll paper loaded into the wrong transportation path, labels are wasted and paper jams or other problems can occur. 
     A problem with a label printer having a label peeling mechanism as described above is that whether or not the label paper is loaded into the correct transportation path of the peeling mechanism must be confirmed, and the printer cannot be immediately and automatically mechanically reset just because the main cover and peeling mechanism cover are closed. 
     The label paper  58  used in a printer having a label peeling mechanism has many labels  60   a ,  60   b  adhesively affixed to the surface of a continuous web liner  59 . When new label paper  58  is loaded into the label peeling mechanism of the printer, a number of labels must be manually removed from the leading end of the label paper  58  so that only the bare web liner  59  is passed around the web-bending guide  53 . This is bothersome for the operator and wastes many labels. 
     Furthermore, if the leading portion of a label affixed to the web liner  59  is positioned to the distal curved portion of the web-bending guide  53  when the label paper is loaded, the leading end of that label disengages from the web liner  59  and exposes the adhesive surface of the label. This adhesive surface can then stick to an internal part of the label printer and interfere with loading the label paper. 
     SUMMARY OF INVENTION 
     An advantage of a label printer having a label peeling mechanism and a control method for a label printer according to the present invention is that whether the roll paper is loaded into the correct transportation path can be appropriately determined when executing the mechanical initialization process that is run when roll paper is loaded, thus solving the foregoing problems. 
     A further advantage of a label printer having a label peeling mechanism and a control method for a label printer according to the present invention is that the label paper can be easily loaded and label waste can be reduced. 
     With a label printing apparatus having a peeling mechanism according to the present invention paper having a plurality of labels continuously affixed to a web liner is loaded inside the label printing apparatus when a main cover is open. A peeling mechanism cover located on the main cover is opened and the paper is then routed through a first or second transportation path according to whether the peeling mechanism is used when. The paper is then conveyed by a paper transportation mechanism when the main cover is closed, and the labels are printed by a print head. This label printing apparatus has a main cover detector for detecting if the main cover is open or closed; a control unit for executing a mechanical initialization process; a switch that is pressed by the operator after the mechanical initialization process runs; and a display unit that starts displaying when the main cover is detected in a closed position and stops displaying when the operator presses the switch. 
     The main cover detector thus detects when the main cover is closed after the operator opens the main cover and sets paper inside the label printer. The display unit of the label printer then starts to display to inform the operator that the paper must be loaded into the label peeling mechanism. The operator then opens the peeling mechanism cover, sets the paper into the appropriate transportation path according to whether the label peeling mechanism is to be used or not, and then closes the peeling mechanism cover. When the operator then operates the switch, the label printer detects operation of the switch and turns the display off, thus informing the operator that the paper has been set and enabling the control unit to run a mechanical initialization process to, for example, remove play (backlash) in the gears. 
     The operator can thus reliably set the paper into the paper transportation path matching the printing purpose in this label printer having a label peeling mechanism. The label peeling position has also completed the mechanical initialization process at this time, and can convey the paper using the paper transportation mechanism for printing by the print head. 
     Furthermore, because the operator must specifically operate the switch, the operator can also confirm that the paper has been correctly loaded and the label printer can reliably position the paper for printing. Problems such as the label printer running the mechanical initialization process and then immediately starting to print even though loading the paper into the label peeling mechanism has not been completed can thus be prevented. An advantage of the present invention is thus that the label printer can dependably execute the mechanical initialization process and the reliability of the label printer can thus be improved. 
     Preferably, this label printing apparatus having a peeling mechanism also has a label detector for detecting the label position while the paper is conveyed. The control unit transports the paper to a position where an operator can remove the label while the label detector detects the position of the label in the mechanical initialization process. 
     When the paper is loaded and a label is located away from the print head and cannot be printed, the label paper can be advanced by the paper transportation mechanism while the label detector detects the position of the label so that the operator can then remove the label. The number of labels that are wasted when loading the label paper can thus be minimized, and the labels can be easily removed. 
     To use the label peeling mechanism, the operator can thus load only the web liner portion of the label paper after removing labels from the web liner into the paper transportation path for using the label peeling mechanism. This is advantageous because only the web liner portion of the label paper should be loaded into the peeling mechanism in order to reduce the load on the paper transportation mechanism. 
     Further preferably, when the switch is pressed in this label printing apparatus, the control unit transports in reverse and positions the leading edge of a label on the paper relative to the print head using the paper transportation mechanism while the label detector detects the label position, and stops the display before transportation or after transportation. 
     When the operator closes the peeling mechanism cover to finish setting the label paper and then operates the switch, the next label located at the print head can be reversed and positioned with the leading edge at a printable position. Wasting labels located at a printable position is thus eliminated. The operator can also be informed that the paper is set and ready for printing. When print data is then received, printing can begin immediately from the leading edge of the label. 
     Yet further preferably, this label printing apparatus also has a peeled label detector for detecting if a label or web liner is in a label discharge opening. When the paper is set in the transportation path for using the peeling mechanism, the control unit transports the paper to a position where an operator can remove the label in the mechanical initialization process. When the peeled label detector detects that the label or the web liner is not in the label discharge opening after the switch is pressed, the control unit transports the label paper in reverse and positions the leading edge of a label on the paper relative to the print head using the paper transportation mechanism while the label detector detects the label position. The display is stopped before or after the label paper is thus conveyed. 
     If a label is positioned away from the print head where the label cannot be printed when the input unit is operated, this aspect of the invention can advance the label to the label discharge opening for easy removal by the operator. When the operator then loads only the web liner portion of the label paper into the transportation path, closes the peeling mechanism cover to complete loading the paper, and operates the switch, the next label located at the print head can be reversed to a printable location, thereby eliminating label waste. The operator can also be informed that the paper is set and ready for printing. When print data is then received, printing can begin immediately from the leading edge of the label. The label printer thus waits until there is no label or web liner in the label discharge opening and the label paper is correctly loaded. 
     Yet further preferably, this label printing apparatus also has a communication unit for reporting a standby state to a host computer when the display unit starts to display. When the switch is pressed, the communication unit reports to the host computer that the standby state was cancelled and the display unit is turned off. 
     The advantage of this aspect of the invention is that the host computer can be informed when the printer is is in a standby state waiting for the switch to be pressed and when this standby state is cancelled. The host computer thus knows the timing for presenting a message prompting the operator to set the paper, and the timing for sending the print data to the printer. 
     Another aspect of the invention is a control method for a label printing apparatus having a peeling mechanism wherein paper having a plurality of labels continuously affixed to a web liner is loaded inside the label printing apparatus when a main cover is open, and when a peeling mechanism cover positioned on the main cover is opened, the paper is conveyed through one or two transportation paths depending on whether or not the peeling mechanism is used, the paper is conveyed by a paper transportation mechanism when the main cover is closed, and the labels are printed by a print head. This control method has steps of: detecting that the main cover is closed; executing a mechanical initialization process and starting a display when the main cover is closed; and stopping the display when a switch is pressed. 
     The main cover detector thus detects when the main cover is closed after the operator opens the main cover and sets paper inside the label printer. The display unit of the label printer then starts to display to inform the operator that the web must be loaded into the label peeling mechanism. The operator then opens the peeling mechanism cover, sets the paper into an appropriate transportation path according to whether the label peeling mechanism is to be used or not, and then closes the peeling mechanism cover. When the operator then operates the switch, the label printer detects the operation and turns the display off, thus informing the operator that the paper has been set. 
     Furthermore, because the operator must specifically operate the switch, the operator can also confirm that the paper has been correctly loaded and the label printer can reliably position the paper for printing. 
     This control method also prevents problems such as the label printer running the mechanical initialization process and then immediately starting to print even though loading the paper to the label peeling mechanism has not been completed. An advantage of the present invention is thus that the label printer can dependably execute the mechanical initialization process and the reliability of the label printer can thus be improved. 
     Preferably, the mechanical initialization process in this control method preferably also has a step of detecting the label position while conveying the paper to a position where the operator can remove the label. 
     When the paper is loaded and a label is located away from the print head and cannot be printed, the operator can then remove the label. The number of labels that are wasted when loading the label paper can thus be minimized, and the labels can be easily removed. To use the label peeling mechanism, the operator can thus load only the web liner portion of the label paper after removing labels from the web liner into the paper transportation path for using the label peeling mechanism. 
     Further preferably, this control method also has a step of transporting the label paper in reverse and positioning the leading edge of a label on the paper relative to the print head while detecting the label position after the switch is pressed. 
     When the operator closes the peeling mechanism cover to finish setting the label paper and then operates the switch, the next label located at the print head can be reversed and positioned with the leading edge at a printable position. Wasting labels located at a printable position is thus eliminated, and printing can begin immediately from the leading edge of the label when print data is then received. 
     Further preferably, after a step of detecting the label position while conveying the paper to a position where the operator can remove the label; this control method also has steps of transporting in reverse and positioning the leading edge of a label on the paper relative to the print head while detecting the label position when the label or the web liner is not detected in the label discharge opening after the switch is pressed when the paper is set in a transportation path using the peeling mechanism; and stopping the display before the transportation step or after the transportation step. 
     If a label is positioned away from the print head where the label cannot be printed when the input unit is operated, this aspect of the invention can advance the label to the label discharge opening for easy removal by the operator. When the operator then loads only the web liner portion of the label paper into the transportation path, closes the peeling mechanism cover to complete loading the paper, and operates the switch, the next label located at the print head can be reversed to a printable location, thereby eliminating label waste. The operator can also be informed that the paper is set and ready for printing. When print data is then received, printing can begin immediately from the leading edge of the label. These operations can also be executed automatically. The label printer thus waits until there is no label or web liner in the label discharge opening and the label paper is correctly loaded. 
     Yet further preferably, another aspect of this control method also has steps of reporting a standby state to a host computer and starting display by the display unit when the main cover is detected in a closed position; and reporting to the host computer that the standby state was cancelled when the switch is pressed, and stopping display by the display unit. 
     The advantage of this aspect of the invention is that the host computer can be informed when the printer is in a standby state waiting for the switch to be pressed and when this standby state is cancelled. The host computer thus knows the timing for presenting a message prompting the operator to set the paper, and the timing for sending the print data to the printer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external oblique view of a label printer according to a preferred embodiment of the present invention; 
         FIG. 2  is a side section view of the label printer shown in  FIG. 1 ; 
         FIG. 3  is an external oblique view showing the label paper replacement method of the label printer shown in  FIG. 1 ; 
         FIG. 4  is an external oblique view showing selection of the paper exit in the label printer shown in  FIG. 1 ; 
         FIG. 5  is a side section view of the label printer shown in  FIG. 4 ; 
         FIG. 6  is a block diagram of the electrical control system of the label printer shown in  FIG. 1 ; 
         FIG. 7  is a flow chart of the mechanical initialization process run by the CPU shown in  FIG. 6 ; 
         FIG. 8  is a block diagram of the electrical system of a label printer according to another embodiment of the invention; 
         FIG. 9  is a flow chart of the label paper loading process run by the CPU shown in  FIG. 8 ; 
         FIG. 10  is a flow chart of the program run by the CPU shown in  FIG. 6  to use the peeling mode; 
         FIGS. 11A to 11D  show the label transportation positions as the CPU runs the process shown in  FIG. 10 ; and 
         FIGS. 12A to 12C  show a label peeling mechanism according to the prior art. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A label printer and control method according to a preferred embodiment of the present invention are described below with reference to the accompanying figures. 
       FIG. 1  is an external oblique view of a label printer according to a preferred embodiment of the present invention, and  FIG. 2  is a side section view showing the internal arrangement of this label printer. As shown in  FIG. 1 , a label printer  1  according to this embodiment of the invention has a printer case  2  with a basically parallelepiped shape. The top portion of the front panel of the printer case  2  is a stationary panel  2   a  fixed to the printer case  2 , and the bottom portion is an openable panel  2   b  (main cover) that opens and closes from the printer case  2 . 
     A label discharge slot  3  is formed between the stationary panel  2   a  and openable panel  2   b . The printed labels  10  are dispensed from this label discharge slot  3  when the label peeling mechanism is used (that is, when in the peeling mode) as illustrated in  FIG. 2 . The printed label paper  8  (with printed labels still attached) is discharged from this label discharge slot  3  when the peeling mechanism is not used (not illustrated in the figure). The peeling mechanism cover  5  (or peeler cover, see  FIG. 4 ) is attached freely openably and closably below the label discharge slot  3  of the openable panel  2   b . Peeling mechanism cover  5  is rotatively connected to and positioned on openable panel  2   b  so that it can be opened and closed from panel  2   b . A web discharge slot  4  for discharging only the web liner  9  when the label peeling mechanism is used is formed at the bottom of the peeling mechanism cover  5 . Nothing is discharged from the web discharge slot  4  when the label peeling mechanism is not used. A manual paper feed switch  6  (input unit) is located together with one or more display LEDs  7  (display unit) on the front left side of the openable panel  2   b . Note that the paper feed switch is shown as a push-button type switch that can be pressed by the operator. However any type of suitable input device could be used, such as toggle switch, a lever or a key on a keyboard. 
     A roll of label paper  8  is stored inside the printer case  2  as shown in  FIG. 2 . This label paper  8  has a series of many adhesive labels  10  of a specific length affixed to the front surface of a continuous web liner  9  wound into a roll that is stored inside the printer. Note that the dot-dash line indicated by reference numeral  90  in  FIG. 2  denotes the transportation path of the web liner  9  when the peeling mechanism is used, and the imaginary line denoted by reference numeral  100  denotes the transportation path of the labels  10  when the peeling mechanism is used. 
     When the label paper is loaded into the printer, the leading end of the label paper  8  is pulled out from the printer case  2  and passed between the print head  11  and platen roller  12  to enable transporting the label paper  8  and printing on the labels  10 . When the label peeling mechanism is used, the web liner  9  is curved acutely to the back (non-label) side of the web around a web-bending guide  13  of the label peeling mechanism and forming an acutely angled curve at the distal end. The web liner  9  is held and conveyed by the drive platen roller  12  and the driven peeler roller  12   a  (pinch roller) that rotates following the platen roller and constituting the paper transportation mechanism, and is discharged from the web discharge slot  4 . 
     When the label paper  8  passes over the web-bending guide  13  of this label peeling mechanism, the labels  10  adhesively affixed to the front surface of the web liner  9  are unable to follow the transportation path of the web liner  9  and are thus disengaged from the web  9 . The peeled labels  10  are then discharged externally from the printer through the label discharge slot  3 . The remaining web liner  9  follows a different transportation path than the labels  10 , and the labels  10  and web liner  9  are thus separated. 
     This label printer  1  also has a label detection sensor  17  (label detector) positioned upstream of the print head  11 , and a peeled label sensor  18  (peeled label detector) positioned near the label discharge slot  3  at a position slightly above the curved end part of the web-bending guide  13 . 
     The label detection sensor  17  detects the difference between light reflected from the label  10  and light reflected from the web liner  9  to detect the passage of the leading end or trailing end of successive labels, and can thereby determine where the label  10  is positioned. The label detection sensor  17  could alternatively operate by detecting the difference in light passing through the web and label. 
     The peeled label sensor  18  detects whether light is reflected from a label  10  to detect whether a discharged label  10  is or is not located in front of the peeled label sensor  18 . Detection signals from the label detection sensor  17  and peeled label sensor  18  are sent to the CPU  20  of the label printer as described below. 
       FIG. 3  is an oblique view showing the openable panel  2   b  of this label printer  1  with a label peeling mechanism when the openable panel  2   b  is pulled forward and opened. This openable panel  2   b  can be pulled forward and opened as shown in  FIG. 3  when the end of the label paper  8  is reached and a new roll of label paper  8  must be loaded into the label printer  1 , or when the label paper  8  is to be replaced with label paper  8  having a different label length or label width. Thus opening the openable panel  2   b  provides access to the label paper  8  storage compartment, and thus enables loading or replacing the label paper  8 . 
       FIG. 4  and  FIG. 5  are an external view and a side section view, respectively, showing how the leading end  8   a  of the label paper  8  is fed outside the printer from the web discharge slot  4  to use the label peeling mechanism. 
     The peeling mechanism cover  5  positioned between the label discharge slot  3  of the openable panel  2   b  and the web discharge slot  4 , and is rotatively connected to open and close freely on the top part of the openable panel  2   b . After the peeling mechanism cover  5  is opened and the leading end  8   a  of the label paper  8  is passed through the web discharge slot  4  as shown in  FIG. 4 , closing the peeling mechanism cover  5  sets the label paper  8  for use in the peeling mode using the label peeling mechanism. 
     The label peeling mechanism functions when the leading end  8   a  of the label paper  8  is pulled outside the case from the web discharge slot  4 . As a result, labels  10  printed by the print head  11  are conveyed with the web liner  9  to the web-bending guide  13 , and the labels  10  are peeled from the web liner  9  at the curved distal end of the web-bending guide  13  and then discharged from the label discharge slot  3  as shown in  FIG. 1  as the label paper  8  is conveyed further downstream with the back of the web liner  9  curving acutely around the distal end of the web-bending guide  13 . 
     If the leading end  8   a  of the label paper  8  is not pulled outside the printer from the web discharge slot  4  and instead is pulled outside the printer from the label discharge slot  3 , that is, if the label paper  8  is loaded so that both the labels  10  and web liner  9  are discharged from the label discharge slot  3 , multiple consecutive labels  10  can be printed and discharged with the labels  10  intact on the web liner  9  in the non-peeling mode. Multiple labels  10  can thus be batch printed. 
     When the leading end  8   a  of the label paper  8  is pulled outside the printer through the appropriate transportation path and the openable panel  2   b  is then closed, the label paper  8  is held between the print head  11  and platen roller  12 . A main cover switch  16  (detection mechanism,  FIG. 6 ) for detecting opening and closing of the openable panel  2   b  (main cover) is positioned at a suitable location on the printer case  2 . 
     To print labels using the label peeling mechanism, the operator sets the leading end  8   a  of the label paper  8  through the web discharge slot  4  as shown in  FIG. 4  and  FIG. 5  and then closes the peeling mechanism cover  5 . A peeler cover switch  19  (detection mechanism,  FIG. 6 ) is positioned near the peeling mechanism cover  5  to detect opening and closing of the peeling mechanism cover  5 , and outputs the detection signal to the CPU  20 . 
       FIG. 6  is a function block diagram of the electrical control system of the label printer  1  shown in  FIG. 1 . A CPU  20  (control unit) controls label printer  1  operation. Connected to the CPU  20  over a bus  21  are a ROM  22 , a RAM  23 , I/O  29  and communication interface  25 . The ROM  22  stores some programs and data, a printing control program and mechanical initialization program for driving the print head  11  and drive motor  15 , a peeling mode setup program, a printing process program, and character data. The RAM  23  functions as temporary storage for storing the label  10  position, received data, and print data generated therefrom, and output data. The peeling mode using the label peeling mechanism and continuous printing (non-peeling) mode can alternatively be set using DIP switches (for example) or the mode setting can be stored in flash ROM (for example) or other nonvolatile memory. 
     A communication interface  25  is connected to the bus  21 , and a personal computer  27  is connected to the communication interface  25  through a cable  26 . The personal computer  27  may have a display, and display an instruction to the operator in accordance with received status data from the label printer  1 . 
     An input/output (I/O) unit  29  is connected to the bus  21 . Connected through the I/O unit  29  to the bus  21  are the label detection sensor  17 , peeled label sensor  18 , print head  11 , drive motor  15  for platen roller  12 , paper feed switch  6 , main cover switch  16 , peeler cover switch  19 , and LED  7 . A display such as a liquid crystals display may used alternatively to LED  7 . In this case, it is possible to display characters. As will be appreciated various signals and commands flow between CPU  20  the devices connected to I/O  29  via bus  21 . For example, CPU  20  controls drive motor  15  with commands and sends print data to print head  11 . Also, input signals from the main cover switch  16  indicate if the cover is open or closed, signals from the paper feed switch  6  indicate if the switch has been pressed, signals from the label detection sensor indicate the position of a label  10 , etc. 
       FIG. 7  is a flow chart of the mechanical initialization process run by the CPU  20  shown in  FIG. 6 . When the operator replaces the roll paper, for example, the CPU  20  executes this mechanical initialization program from ROM  22 . 
     More specifically, the main cover switch  16  sends an OPEN signal to the CPU  20  when the operator opens the openable panel  2   b  and installs roll paper  8 , and the CPU  20  thus starts the mechanical initialization process. Note that a sensor can be positioned where the label paper  8  is stored and control can be based on output from this sensor. 
     After the label paper  8  is loaded, the mechanical initialization program waits until the main cover switch  16  closes (step S 1 ). When the main cover switch  16  closes, the label paper  8  is conveyed forward a specific distance by the platen roller  12  driven by the drive motor  15  to remove play (backlash) in the gears, for example (step S 2 ). Preferably during step S 2  the label paper  8  is advanced while the label detection sensor  17  detects the label  10  position so that the trailing end or leading end of the labels can be determined, a label  10  that is positioned away from the print head  11  where the label cannot be printed can be detected, and the label  10  can be advanced to a position where the label  10  can be removed by the operator ( FIG. 11A  and  FIG. 11B ). The smallest number of labels  10  in a non-printable position can thus be removed ( FIG. 11C ). 
     In the peeling mode using the label peeling mechanism, the web liner  9  from which unprintable labels  10  have been removed can be routed through the web transportation path  90  in  FIG. 2  between the platen roller  12  and peeler roller  12   a . The LED  7  can also be driven to blink as a way of prompting the operator to set the label paper  8  into the transportation path for the peeling mode using the label peeling mechanism or the continuous printing mode not using the label peeling mechanism, and then press the paper feed switch  6  to indicate when the label paper  8  has been loaded. The personal computer  27  (host) is also informed (via status data) that the printer is waiting for the operator to press the paper feed switch  6  (step S 3 ). The personal computer  27  can also display a message prompting the operator to route the label paper  8  in accordance with a specific mode. Instructions for loading the label paper  8  can also be displayed to help ensure that the operator loads the label paper  8  correctly. 
     The CPU  20  also determines whether the peeler cover switch  19  is open or closed and waits for an indication that the peeler cover switch  19  is closed (step S 4 ). If the peeler cover switch  19  is open, the operator is loading the label paper  8  and the peeling mechanism cover  5  is not closed, and the CPU  20  therefore waits to proceed to step S 5 . This prevents the label indexing operation (step S 7 ) and subsequent printing process from running if the paper feed switch  6  is accidentally pressed while the peeling mechanism cover  5  is open, or if the peeling mechanism cover  5  is closed to finish loading the paper but the operator then realizes that the paper is not correctly loaded (not execute step S 5 ). 
     After the CPU  20  determines that the peeler cover switch  19  is closed, the CPU  20  waits for the operator to press the paper feed switch  6  (step S 5 ). 
     The operator presses the paper feed switch  6  after confirming the mode indicated by the LED  7 , setting the label paper  8  appropriately to the mode, closing the peeling mechanism cover  5 , and confirming that the label paper  8  is set to the desired mode. 
     The CPU  20  turns the LED  7  off after detecting that the paper feed switch  6  was pressed and reports to the personal computer  27  (via status data) that the standby state waiting for the paper feed switch  6  to be pressed has been cancelled (step S 6 ). The personal computer  27  thus knows that the label paper  8  is set for the specified mode, and knows the timing for preparing and sending print data to the label printer  1 . 
     The label paper  8  is then reversed while the label detection sensor  17  detects the position of the label  10 , and the next label located at the print head can thus be reversed and the leading end of the label can be returned to the printable position (label indexing process) (step S 7 ) ( FIG. 11D ). After step S 7  the CPU  20  reads the printing control program and prints labels  10  based on the print data received from the personal computer  27 . 
     Note that the sequence of steps S 6  and S 7  can be reversed. 
     The label indexing process is described more specifically below. 
     The peeled label sensor  18  in this embodiment of the invention is located downstream in the label transportation direction from the print head  11 . Therefore, when the peeled label sensor  18  detects the leading end of a label, a specific number of reverse (or forward) rotation drive pulses are supplied to the drive motor (a stepping motor) of the platen roller  12  to position the leading edge of the label relative to the print head  11  ( FIG. 11D ). 
     If the paper is advanced forward in step S 2  and stops when the label detection sensor  17  detects the leading edge of the label, the mechanical initialization is controlled by supplying a specific number of forward rotation drive pulses to the drive motor  15  in step S 7  because the label detection sensor  17  is located upstream from the print head  11  in the transportation direction. 
     As described above the label indexing process does not run until the paper feed switch  6  is operated. The printer is therefore prevented from running the initialization process and starting to print even though loading the label paper  8  is not completed. 
     Furthermore, by displaying an indication prompting the user to set the label paper  8 , the operator can also easily know that the label printer  1  is not ready to print, press the paper feed switch  6  after setting the label paper  8 , and thus control operation after confirming that the paper is correctly loaded. 
     This embodiment of the invention also has a peeler cover switch  19  as described above, and the CPU  20  detects the open or closed status of the peeler cover switch  19  in step S 4  in  FIG. 7 . However, because process execution can also be controlled based on whether or not the paper feed switch  6  is pressed, the peeler cover switch  19  and step S 4  are not always necessary and can be omitted. An aspect of the invention in which these are omitted is shown in  FIG. 8  and  FIG. 9 . 
       FIG. 8  is a function block diagram showing the electrical control system of a label printer according to another embodiment of the present invention. Connected over a bus  21  to the CPU  20  that controls the label printer are ROM  22  for storing certain programs and data, including the printing control program and mechanical initialization program, and RAM  23  that functions as temporary memory. A communication interface  25  is connected to the bus  21 , and a personal computer  27  used as the host computer of the label printer  1  is connected through a cable  26  connected to the communication interface  25 . An I/O unit  29  is also connected to the bus  21 . Connected through the I/O unit  29  are label detection sensor  17 , print head  11 , drive motor  15  for the platen roller  12 , paper feed switch  6 , main cover switch  16 , peeled label sensor  18 , and LED  7 . Note that a peeler cover switch  19  is not provided. 
       FIG. 9  is a flow chart showing the mechanical initialization program run by the CPU  20  shown in  FIG. 8 . Steps S 1 , S 2 , S 3 , S 5 , S 6 , and S 7  are identical to the steps of the same numbers in the flow chart shown in  FIG. 7 , while step S 4  shown in  FIG. 7  is omitted. As described above, the order of steps S 6  and S 7  can be reversed. 
     This embodiment of the invention enables omitting the peeler cover switch  19 , and thus has the additional advantage of being able to lower the manufacturing cost of the printer. 
       FIG. 10  is a flow chart showing the peeling mode setup program using the peeled label sensor  18 . The operator opens the openable panel  2   b  (main cover) of the label printer  1  as shown in  FIG. 3 , places a new roll of label paper  8  inside the label printer  1 , and sets the leading end  8   a  of the label paper  8  in front of the peeled label sensor  18 . When the openable panel  2   b  is then closed to hold the paper between the print head  11  and platen roller  12 , the CPU  20  reads the peeling mode setup program from ROM and runs the program. 
     The CPU  20  first detects the status of the main cover switch  16  and waits for the openable panel  2   b  (main cover) to be closed (step S 1 ). When the openable panel  2   b  is closed, step S 1  returns YES and control goes to step S 2 . 
     The CPU  20  then outputs a forward feed command to the drive motor  15  in step S 2 , and the position of the first label  10   a  on the web liner  9  thus advances as shown in  FIG. 11A . Web transportation stops when the first label  10   a  affixed to the web liner  9  reaches a position where the label can be removed as shown in  FIG. 11B , and control goes to step S 3 . 
     Whether the first label  10   a  has reached a peelable position can be calculated by the CPU  20  based on the distance of platen roller  12  rotation and whether the label detection sensor  17  detects the leading edge or trailing edge of the first label  10   a  or the leading edge or trailing edge of the next label  10   b . This calculation could alternatively be based on the distance of platen roller  12  rotation after the peeled label sensor  18  detects the leading edge of the first label  10   a.    
     The operator is then prompted by flashing the LED  7 , for example, and the personal computer  27  (host computer) is informed (via the status data) that the CPU  20  is waiting for the paper feed switch  6  to be pressed (step S 3 ). With the peeling mechanism cover  5  open as shown in  FIG. 4  and  FIG. 5 , the operator then peels the first label  10   a  positioned as shown in  FIG. 11B  from the web liner  9 , passes the now-bare leading end of the web liner  9  around the web-bending guide  13  of the label peeling mechanism from the back side of the web and out through the web discharge slot  4  (the web transportation path  90  in  FIG. 2  between the platen roller  12  and peeler roller  12   a ), closes the peeling mechanism cover  5 , and presses the paper feed switch  6 . 
     The peeled label sensor  18  then determines if a label is present in the label dispenser slot (step S 8 ). If the peeled label sensor  18  determines that the first label  10   a  or web liner  9  is not present in the label dispenser slot, the label paper  8  is loaded as shown in  FIG. 11C . When the CPU  20  then detects that the paper feed switch  6  was pressed (step S 5 ), the CPU  20  turns the LED  7  off and reports to the personal computer  27  that the standby state waiting for the paper feed switch  6  to be pressed has been cancelled (step S 6 ). 
     The label paper  8  is then reversed while the label detection sensor  17  detects the position of the label  10 , and the next label located at the print head can thus be reversed and the leading end of the label can be returned to the printable position (label indexing process) (step S 7 ). If the peeled label sensor  18  detects the first label  10   a  or web liner  9  at this time (step S 8  returns no), operation waits until the first label  10   a  or web liner  9  is removed from the label dispenser slot even if the paper feed switch  6  is pressed. Operation advances to the next step only when the paper feed switch  6  is pressed after the first label  10   a  and web liner  9  are removed and step S 8  returns yes. This sequence ensures that the label paper  8  is correctly loaded. 
     Note that the sequence of steps S 6  and S 7  can be reversed. 
     The CPU  20  waits for the paper feed switch  6  to be pressed in step S 5 . When the CPU  20  detects that the paper feed switch  6  was pressed, the CPU  20  outputs a reverse feed command to the drive motor  15  of the platen roller  12  to position the leading edge of the next label  10   b  relative to the print head  11 , and thus controls transporting the next label  10   b  to the label indexing position as shown in  FIG. 11D . The distance from the label peeling position to the label indexing position is determined by the length of the label, and the label position can be easily calculated and controlled based on the label length, the gap between labels, and how far the platen roller  12  turns. The printing process is then controlled according to the printing control program, by the CPU  20 . 
     The number of labels  10  that must be peeled before printing starts can thus be limited to the one label, that is, the first label  10   a , and label  10  waste can thus be reduced when opening the openable panel  2   b  of the label printer  1  and loading the label paper  8  with this embodiment of the invention. Loading the label paper is therefore easier because peeling a label  10  before setting the label paper is not necessary, and is also more efficient because the adhesive side of the label is not exposed when loading the paper. 
     It will be evident to one with ordinary skill in the related art that the main cover, peeling mechanism cover, detection mechanism, and control mechanism of a label printer having a label peeling mechanism according to the present invention shall not be limited to the arrangements described in the foregoing embodiments and can be varied in many ways without departing from the scope of the accompanying claims. 
     For example, the print head  11  of a label printer according to the present invention is commonly a thermal print head or an inkjet print head, but the invention shall not be so limited and can be applied to a label printer having a different type of print head. 
     Although the present invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.