Patent Publication Number: US-6338555-B1

Title: Hand-held printer

Description:
FIELD OF THE INVENTION 
     This invention relates to a hand-held printer and relates to a method for printing one print line at a time using a hand-held printer. 
     BACKGROUND OF THE INVENTION 
     A thermal-transfer type handy printer that printing is conducted by moving the printing head by hand has been proposed (for example, Japanese patent application laid-open No. 2-2029 (1990)). In such a conventional hand-held printer, printing is conducted by moving the printer in a certain direction and thereby forwarding a print film while pressing the thermal head against the surface of a paper or an article to be printed. 
     Thus, in the conventional hand-held printer, the thermal head needs to be pressed through the print film against a print surface with a relatively high pressure because it employs the thermal transfer system. However, it is difficult to keep the pressure constant. Further, it is very difficult to keep the moving speed constant because the printing head needs to be moved in a certain direction by hand. Therefore, accuracy or concentration in printing cannot be stabilized. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a hand-held printer that can give enhanced printing quality without requiring high pressure. 
     It is a further object of the invention to provide a hand-held printer that can stably provide a single high-quality printer line. 
     It is a further object of the invention to provide a method for printing one print line by using a hand-held printer that can give enhanced printing quality without requiring high pressure. 
     According to the invention, a hand-held printer, comprises: 
     an ink jet head with a plurality of aligned ink nozzles; 
     means for moving the ink jet head in the orthogonal direction to the aligned direction of the plurality of ink nozzles; 
     a printer case that covers a movable range of ink jet head and has an opening on the side facing the plurality of ink nozzles; and 
     a handle provided on the printer case. 
     According to another aspect of the invention, a hand-held printer, comprises: 
     a printer head and a holder for holding the printer head; 
     wherein the printer head comprises an ink jet head with a plurality of aligned ink nozzles, means for moving the ink jet head in the orthogonal direction to the aligned direction of the plurality of ink nozzles, a printer case that covers a movable range of the ink jet head and has an opening on the side of the plurality of ink nozzles, and a handle provided on the printer case, and the holder comprises means for receiving the printer head, and means for covering the plurality of ink nozzles of the ink jet head when the printer is received into the receiving means. 
     According to another aspect of the invention, a method for printing one print line by using a hand-held printer with a handle, comprises the steps of: 
     receiving print data corresponding to one print line; and 
     discharging ink from a plurality of aligned ink nozzles on an ink jet head of the hand-held printer while moving the ink jet head in the orthogonal direction to the aligned direction of the plurality of ink nozzles according to the print data. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail in conjunction with the appended drawings, wherein: 
     FIG. 1 is a perspective view showing a hand-held printer in a preferred embodiment according to the invention. 
     FIG. 2 is a partial cross sectional view of the hand-held printer in FIG. 1, 
     FIG. 3 is a longitudinal sectional view taken along line III—III of FIG.  2 . 
     FIG. 4 is a cross sectional view of an ink cartridge in FIG. 2, 
     FIG. 5 is an illustration showing a print-possible range of the hand-held printer in the embodiment. 
     FIG. 6 is a circuit diagram showing the hand-held printer in the embodiment, and 
     FIG. 7 is an illustration for explaining the operation of the hand-held printer in the embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A hand-held printer in the preferred embodiment will be explained in FIG.  1 . As shown, the hand-held printer comprises a print head  101  and a special-purpose holder  102 . The printer head  101  has a case  103  with a cross section elongated in one direction, in which means for printing, e.g., an ink jet head, which is explained later, is contained. A handle  104 , by which a user can hold the printer head  101  by one hand, is provided on the middle upper part of the case  103 . Also, there is provided a detachable cover  105  for changing an ink cartridge on one upper end of the case  103 . 
     On the upper part of the holder  102 , receiving part  106  to receive the printer head is provided. On one end of the receiving part  106 , there is provided a cap  107 , explained later, for preventing an ink jet head  203  from drying when it is not used. The holder  102  is powered through an AC power source cord  108 , and the power source is turned on/off by a power source switch  109 . Also, the printer head  101  is connected through a connecting cable  110  to the holder  102 , and the holder  102  is connected through a connecting cable  111  to the printer port of a personal computer (PC). The handle  104  is provided with a print switch  112 , an on-line/off-line switch  113  and LED  114 . 
     FIG. 2 is a schematic cross sectional view of the hand-held printer and FIG. 3 is a longitudinal sectional view taken along line III—III of FIG.  2 . In the case  103  of the printer head  101 , a carriage  201  is disposed so that it can move in the longitudinal direction (Z direction) of the case  103 . An ink cartridge  202  and an ink jet head  203  are fixed to the carriage  201 . The ink cartridge  202  is detachably fixed to the upper part of the carriage  201  with its ink-supplying port directed downward. The ink jet head  203  is fixed facing downward in the direction of the opening of the case  103 . Meanwhile, such a one-body type ink cartridge that the ink jet head  203  is attached to the lower end of the ink cartridge  202  may be also used. 
     On the front and back sides of the carriage  201 , grooves extending in the horizontal direction (Z direction) are provided. These grooves are engaged with guide rails  204  formed on the inside wall of the case  103 . Thereby, the carriage  201  being supported is movable in the Z direction. The carriage  201  is provided with a through-hole corresponding to a screw shaft  205 . By rotating the screw shaft  205  by a motor, the carriage  201  can be traveled in the Z direction. As shown in FIG. 3, several ink discharge nozzles  304  on the ink jet head  203  are placed in the orthogonal direction to the moving direction (Z direction) of the carriage  201 . 
     Also, a circuit board  207  for processing a control signal and print data to be input through the holder  102  from PC and controlling the ink jet head  203  and the motor  206  is disposed in the case  103 . Meanwhile, the circuit board  207  is electrically connected through a flexible wiring board (not shown) with the ink jet head  203 . 
     Further, lower ends  208  of the case  103  extend lower than the ink discharge nozzles  304  of the ink jet head  203 . Thereby, the ink discharge nozzles  304  can be located with a certain distance from a recording medium  209 , such as a paper. Namely, its user only has to put the printer head  101  on a desired position of the recording medium  209  while holding the handle  104 . 
     FIG. 4 is a schematic cross sectional view showing an example of the ink cartridge  202 . Ink  301  in the cartridge  201  is constantly supplied through a sponge filter  302  disposed inside the cartridge  201  to an ink supply port  303 . 
     FIG. 5 is an illustration explaining a print-possible range of the ink jet head of the hand-held printer in the embodiment. When the ink jet head  203  has an lineup length of H for the ink supply nozzles  304  and a maximum travel length of L in the Z direction, the height, h of one print line, e.g., “A123”, is set to be less than H, and the print-possible length, l thereof is also set to be less than the maximum travel length L. 
     FIG. 6 is a schematic circuit diagram showing the hand-held printer in the embodiment. The printer head  101  transmits a control signal through an interface circuit  401  to a host PC and receives a print control signal and print data from the host PC. A processor (CPU)  402  controls a control signal sequence for data reception and stores the received print data in a data memory  403 . The stored print data are read out by the user&#39;s operation of a print switch  112 , and then a head driver  404  drives the ink jet head  203  according to the control of the processor  402  and a motor driver  405  simultaneously drives the motor  206 . Thereby, the ink jet head  203  discharges ink dots from the ink discharge nozzles  304  while moving in the Z direction. As a result, one-line printing is performed as shown in FIG.  5 . The interface circuit  401 , processor  402 , a data memory  403 , head driver  404  and motor driver  405  can be installed in the circuit board  207  disposed in the case  103 . 
     FIG. 7 is an illustration explaining the operation of the hand-held printer in the embodiment. First, by switching on the power source switch  109 , the processor  402  initializes the data memory  403 , etc. and turns on LED  114  when data reception from the host PC is enabled. Then, when one-line print data received from the host PC are stored in the data memory  403 , the processor  402  notifies the completion of data reception to the host PC and controls LED  114  to turn on and off. After confirming the turning on and off of LED  114 , its user put the printer head  101  on a desired position of the recording medium  209  while holding the handle  104  and presses down the print switch  112 . Thereby, the ink jet head  203  discharges ink dots from the ink discharge nozzles  304  while moving in the Z direction. As a result, one-line printing is performed. To stop the printing, for example, after pressing down the on-line/off-line switch  113 , the user has only to press down the print switch  112 . 
     Although the invention has been described with respect to specific embodiment for complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modification and alternative constructions that may be occurred to one skilled in the art which fairly fall within the basic teaching here is set forth.