Abstract:
A two-dimensional auto compensated multi-axis tolerance adaptive system used in the cartridge carrier of an inject office machine is constructed to include a carrier unit, a reciprocation mechanism, and a driving mechanism, the carrier unit having a clearance sensor and a bias sensor, the driving mechanism including a rotating unit fastened pivotally with the carrier unit and a lifting unit coupled to the reciprocation mechanism for a linear movement for enabling the plane of rotation of the rotating unit to form with the straight lifting line of the lifting unit a X-Y plane and Z-axis space coordinates system. By means of the detection and scanning of the clearance sensor and the bias sensor, the ink cartridge carrier actively controls the optimum printing clearance between the ink jet nozzle and the media.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a dual-axis or multi-axis motion implement and, more specifically, to a two-dimensional auto compensated multi-axis tolerance adaptive system for adjusting clearance between nozzle and media, and automatically positioning of the ink jet cartridge of an ink jet office machine such as ink jet printer, ink jet plotter, or the like. 
     2. Description of the Related Art 
     In variety of implements, the principle of axial movement is employed to adjust the operation position, so as to achieve material treatment. A printer is one of the important data output implements of a computer system that employs the principle of axial movement to adjust the operation position. Nowadays, an ink jet printer has become one of the standard equipment of a computer system for the advantages of abundant color variation and reasonable cost. When designing an ink jet printer, the ink jet quality control is the most important factor to be taken into account. A good printing quality shows the reality of the data, and depends on the quality of the ink used and the control of the optimum printing environment between the ink cartridge carrier and the media. 
     FIG. 1 shows the ink cartridge carrier of an ink jet printer according to the prior art. As illustrated, the ink cartridge carrier comprises a carrier unit  7  and a reciprocation mechanism  8 . The carrier unit  7  is fixedly fastened to the reciprocation mechanism  8 . The reciprocation mechanism  8  comprises a bearing block  80 , and an axle bearing  82  fixedly fastened to the bearing block  80  by screws  81  and coupled to an axle for enabling the reciprocation mechanism  8  to be moved along the axle so as to achieve the ink jet nozzle  70  reciprocating printing job. Further, a media feed tray and a media feed roller assembly are provided below the ink cartridge carrier for feeding media for printing. According to this design, the clearance between the ink jet nozzle and the media is mechanically controlled by means of the adjustment of an adjustment rod in the housing of the ink jet printer relative to the axle of the ink cartridge carrier. Due to the limitation of the space arrangement of the housing of the ink jet printer and the related component parts, the adjustment rod can only adjust the ink cartridge carrier between limited positions, that do not fit the thickness of a variety of media. If the clearance between the ink jet nozzle and the media is excessively high, the jetted ink may disperse. If the clearance between the ink jet nozzle and the media is excessively low, the problem of ink dragging may occur, resulting in a poor printing quality and contamination of the media. 
     Further, the component parts of an ink jet printer have a manufacturing error due to the error of molds. When the component parts of an ink jet printer assembled, an assembly error exists. For example, the axle of the ink cartridge carrier and the axles of the media feed roller assembly may not perfectly be set in parallel, the axles may be biased due to an error of the related axle bearings or axle holes. The biasing of the axles and the dimensional error between the ink cartridge and the ink cartridge carrier as well as the error of angle between the ink jet nozzle and the ink cartridge result in line trace discontinuous and biasing 
     Therefore, it is desirable to provide an ink cartridge carrier control system that eliminates the aforesaid drawbacks. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a two-dimensional auto compensated multi-axis tolerance adaptive system, which enables the ink jet printer to maintain the optimum printing distance when printing different thickness of media, preventing dragging of ink and improving the printing quality. It is another object of the present invention to provide a two-dimensional auto compensated multi-axis tolerance adaptive system, which compensates and absorbs the error of component parts of the ink jet printer, the manufacturing error and the assembly error, eliminating line trace discontinuous and biasing. According to the invention, the two-dimensional auto compensated multi-axis tolerance adaptive system is used in a multi-axis motion implement to drive the multi-axis motion implement and to record the driving action in an object, the two-dimensional auto compensated multi-axis tolerance adaptive system comprising: a carrier unit, the carrier unit comprising a clearance sensor and a bias sensor; a reciprocation mechanism installed in the multi-axis motion implement to make a reciprocating motion; and a driving mechanism, the driving mechanism comprising a rotating unit fastened pivotally with the carrier unit, and a lifting unit coupled to the reciprocation mechanism for a linear movement for enabling the plane of rotation of the rotating unit to form a X-Y plane and Z-axis space coordinates system with the straight lifting line of the lifting unit. The clearance sensor of the carrier unit measures the distance between the carrier unit and the object, compares the measured data with a built-in comparison table, and drives the lifting unit to move the carrier unit in Z-axis direction according to the comparison result. The bias sensor of the carrier unit scans an initial calibration pattern of the object, compares the scanned data with a built-in comparison table, and drives the rotating unit to move the carrier unit on X-Y plane in Z-axis direction according to the comparison result. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic plain view of an ink cartridge carrier for ink jet printer according to the prior art. 
     FIG. 2 is an exploded plain view of the present invention. 
     FIG. 3 is an assembly plain view of the present invention. 
     FIG. 3A is an enlarged view of part A of FIG.  3 . 
     FIG. 3B is an enlarged view of part B of FIG.  3 . 
     FIG. 4 is a schematic plain view of the lifting unit of the two-dimensional auto compensated multi-axis tolerance adaptive system according to the present invention before its operation. 
     FIG. 5 is a schematic plain view of the lifting unit of the two-dimensional auto compensated multi-axis tolerance adaptive system according to the present invention when obtained the optimum printing clearance. 
     FIG. 6 is a schematic plain view showing the line trace of the initial calibration pattern for the scanning of the bias sensor according to the present invention. 
     FIG. 7 is a schematic plain view showing the motion of the pinion and the serrated portion and the compensation of the angle of error. 
     FIG. 8 is a clearance calibration flow chart according to the present invention. 
     FIG. 9 is a bias calibration flow chart according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 2 and 3, the two-dimensional auto compensated multi-axis tolerance adaptive system of the present invention is used in a multi-axis motion implement, for example, the ink cartridge carrier of a ink jet printer to control the motion of the ink cartridge carrier and to record the driving action in an object (In this embodiment, the object could be a sheet of media). The ink cartridge carrier comprises a carrier unit  1 , a reciprocation mechanism  2 , and a driving mechanism  3 . 
     The carrier unit  1  is adapted to carry an ink cartridge  10 , comprising an ink jet nozzle  11 , which may be formed integral with the ink cartridge.  10  or the carrier unit  1 , a clearance sensor  12  and a bias sensor  13  around the border area of the ink jet nozzle  11 , a rear side wall  14 , two lugs  15  protruded from top and bottom sides of the rear side wall  14  and defining a respective pivot hole  18 , a serrated portion  16  formed in the rear side wall  14 , a signal line  17  electrically connected to the circuit board of the ink jet printer (not shown) for transmission of printing commands. 
     The reciprocation mechanism  2  is installed in the multi-axis motion implement (ink jet printer) for reciprocating motion, comprised of an axle bearing  20 , a belt carrier  21 , a guide screw hole  22 , and a plurality of dovetail grooves  24  arranged in parallel to the guide screw hole  22 . The axle bearing  20  is coupled to one axle of the ink jet printer (not shown), for enabling the ink cartridge carrier to be reciprocated along the axle so that the ink jet nozzle  11  can execute the reciprocating printing job. The belt carrier  21  is covered with vibration absorbing rubber  25 , and used to hold the belt  23  of the ink jet printer so that the motor of the ink jet printer can drive the belt  23  to reciprocate the ink cartridge carrier along the axle. 
     The driving mechanism  3  comprises a rotating unit  30  and a lifting unit  40 . The rotating unit  30  comprises a rotary driver  31  and an encoder  32 . The rotary driver  31  can be a motor held in position by a C-shaped clamp  33 , having a pinion  34  and an encoder wheel  35  at two distal ends of the output shaft thereof. The pinion  34  is meshed with the serrated portion  16  of the carrier unit  1  (see FIG.  3 A). The encoder wheel  35  is peripherally received in the encoder  32  of the rotating unit  30 . The rotating unit  30  further comprises two pivot pins  36  axially aligned with the rotary driver  31  and respectively pivoted to the pivot holes  18  of the lugs  15  of the carrier unit  1 . The lifting unit  40  comprises a lifting driver  41  and an encoder  42 . The lifting driver  41  can be a motor held in position by a C-shaped clamp  43 , having a guide screw  44  and an encoder wheel  45  at two distal ends of the output shaft thereof. The guide screw  44  is threaded into the guide screw hole  22  of the reciprocation mechanism  2 . The encoder wheel  45  is peripherally received in the encoder  42  of the lifting unit  40 . The lifting unit  40  further comprises dovetail rails  46  respectively coupled to the dovetail grooves  24  of the reciprocation mechanism  2  (see FIG.  3 B), for enabling the lifting unit  40  to be coupled to the reciprocation mechanism  2  and moved relative to the reciprocation mechanism  2 . The driving mechanism  3  has a circuit board  5  fixedly secured thereto. The circuit board  5  has signal lines  50  and  51  respectively connected to the encoders  42  and  32  to provide clearance control and angle control feedback signals. The circuit board  5  is also connected to the signal line  17  to transmit commands to the lifting driver  41  and the rotary driver  31 . The circuit board  5  further comprises a flexible printed circuit board  52  supported on a soft cushion pad  53  for the connection of the circuits (not shown) of the carrier unit  1  for transmitting printing commands. 
     Referring to FIG. 4, a media feed tray  6  and a media feed roller assembly  65  are provided at one side of the ink jet nozzle  11 . The sheet feeding direction of the media feed tray  6  is perpendicular to the sliding direction of the reciprocation mechanism  2 . The media feed tray  6  is disposed in parallel to the space detection plane  60  of the clearance sensor  12  and the bias sensor  13 . The space detection plane  60  is disposed in parallel to the plane of rotation between the serrated portion  16  of the carrier unit  1  and the pinion  34  of the rotating unit  30 . The direction of the normal line of the space detection plane  60  is the direction of the guide screw  44  of the driving mechanism  3  such that the plane of rotation of the rotating unit  30 , i.e., the space detection plane  60  forms with the straight lifting line of the guide screw  44  of the lifting unit  40  a X-Y plane and Z-axis space coordinates system, in which the initial distance between the ink jet nozzle  11  of the carrier unit  1  and the media feed tray  6  is D 0 , and the optimum printing clearance of the space detection plane  60  is D 1 . 
     Regarding to the calibration of ink jet clearance, please refer to the flow chart of FIG.  8  and also to FIGS. 4 and 5. When the object, i.e., a sheet of media  61  put in the media feed tray  6 , the clearance sensor  12  detects the distance D 2  between the ink jet nozzle  11  of the carrier unit  1  and the sheet of media  61 , and compares the value of the distance D 2  with the comparison table set in the two-dimensional auto compensated multi-axis tolerance adaptive system, so as to obtain the optimum ink jet clearance adjustment value ΔD. The comparison table is built according to the thickness of a variety of media. The data of comparison result thus obtained is fed back for closed loop control through an algorithm. When the distance D 2  between the ink jet nozzle  11  of the carrier unit  1  and the sheet of media  61  was shorter or greater than the optimum printing clearance D 1 , the lifting driver  41  of the lifting unit  40  is started to rotate the guide screw  44  upwards or downwards, thereby causing the dovetail rails  46  of the driving mechanism  3  to be moved along the dovetail grooves  24  of the reciprocation mechanism  2 , and therefore the ink jet nozzle  11  of the carrier unit  1  is adjusted along the guide screw  44  in Z-axis direction to reach the optimum printing clearance D 1 . 
     Regarding to the calibration of ink jet nozzle printing angle, please refer to the flow chart of FIG.  9  and also to FIG.  6 . When the sheet of media  61  moved forwards subject to the media feeding direction  64 , the ink jet nozzle  11  makes a forward stroke test line trace printing, enabling the sheet of media  61  to record the result of action and to be printed with an initial calibration pattern  62 . When the ink jet nozzle  11  moving back, the bias sensor  13  of the carrier unit  1  scans the initial calibration pattern  62  to determine if there is an angle of error θ between the line trace and the media feeding direction straight line  63  or not. The angle of error θ scanned is compared to the pattern default value comparison table built in the two-dimensional auto compensated multi-axis tolerance adaptive system. The data of the comparison result is fed back for closed loop control through an algorithm. If the angle of error θ&gt;0 or &lt;0, as shown in FIG. 7, the rotary driver  31  of the rotation unit  30  drives the pinion  34  to turn the serrated portion  16  of the carrier unit  1  clockwise or counter-clockwise, thereby causing the ink jet nozzle  11  to be adjusted on the X-Y plane along Z-axis to the optimum printing angle. Therefore, the straight lines printed by the ink jet nozzle  11  are maintained in parallel to the media feeding direction straight line  63 , eliminating the occurrence of line trace biasing. 
     As indicated above, the two-dimensional auto compensated multi-axis tolerance adaptive system of the present invention has the following advantages: 
     1. The arrangement of the clearance sensor of the carrier unit and the lifting unit of the driving mechanism enables the ink jet printer to measure the distance between the ink jet nozzle and the media and to make the proper vertical position adjustment, so as to maintain the optimum printing clearance during printing, preventing dragging of ink and improving the printing quality. 
     2. The arrangement of the bias sensor of the carrier unit and the rotating unit of the driving mechanism enables the ink jet nozzle to adjust the angle of error subject to the initial calibration pattern, so as to compensate and absorb the error of component parts of the ink jet printer, the manufacturing error, and the assembly error, eliminating line trace biasing and discontinuous then improving the printing quality. 
     While only one embodiment of the present invention has been shown and described, it will be understood that various modifications and changes could be made thereunto without departing from the spirit and scope of the invention.