Patent Publication Number: US-8118409-B2

Title: Acoustic ink jet printer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an acoustic ink jet type recording apparatus (an acoustic ink jet printer). 
     2. Description of the Related Art 
     To date, as acoustic ink jet printers, ones having various structures have been known. 
     For example, an acoustic ink jet printer disclosed in JP-A-2001-232793 is known wherein ink is caused to be spattered from a nozzle of a recording head by a vibration, and a recording printing is carried out on recording paper. 
     However, with the heretofore described kind of heretofore known ink jet printer, it is necessary to replace a head unit, including the expensive recording head, in the event that the nozzle clogs, which is a factor in an increase in cost. Furthermore, an ink cartridge with a complex structure is necessary, which point is also a cause of an increase in cost. 
     Also, when aiming for a colorization of the printer, it is necessary to prepare a spattering oscillator, or the like, for each color, which is a cause of complicating the apparatus, and of an increase in cost. 
     The invention having been contrived bearing in mind this kind of circumstance, an object thereof is to obtain an ink jet printer with which a replacement of the whole head unit is unnecessary even in the event of a clogging or the like occurring in the nozzle, and with which, a simplification of the structure of the ink cartridge being possible, and furthermore, a simplification of the apparatus being achieved even when colorizing, a reduction in cost is possible. 
     SUMMARY OF THE INVENTION 
     In order to achieve this kind of object, according to one aspect of the invention, an acoustic ink jet printer in which ink is selectively spattered onto recording paper from a recording head, and a printing carried out, is configured in such a way as to divide the recording head into an ink unit and piezoelectric body unit, and carry out a printing by moving the ink unit on the piezoelectric body unit. 
     According to one aspect of the invention, an acoustic ink jet printer in which ink is selectively spattered onto recording paper from a recording head, and a printing carried out, is configured in such a way as to divide the recording head into an ink unit and piezoelectric body unit and, as well as disposing the piezoelectric body unit penetrating the ink unit, carry out a printing by moving the ink unit in a main scanning direction. 
     The acoustic ink jet printer according to one aspect of the invention is configured in such a way as to use a plurality of ink cartridges as the ink unit, and dispose the plurality of ink cartridges on the piezoelectric body unit. 
     The acoustic ink jet printer according to the first or second aspect of the invention is configured in such a way as to use only necessary ink cartridges as the ink unit, and dispose only the necessary number of ink cartridges on the piezoelectric body unit. 
     As heretofore described, according to one aspect of the invention, as the acoustic ink jet printer is configured in such a way as to divide the recording head into the ink unit (the ink cartridge, or the like) and piezoelectric body unit (a recording head unit), and move the ink unit on the piezoelectric body unit, it is possible to use an ink unit (the ink cartridge, or the like) with a simple configuration, by which means it is possible to achieve a reduction in cost. 
     Also, according to one aspect of the invention, there is no need to replace the whole of the expensive recording head even in the event of a problem occurring, and furthermore, with regard to the ink spattering too, as heat is not used, there is also an advantage in that there is a wide range of choice of ink. 
     Also, according to one aspect of the invention, as the acoustic ink jet printer is configured in such a way as to divide the recording head into the ink unit and piezoelectric body unit, cause the piezoelectric body unit to penetrate the ink unit, and carry out a printing by moving the ink unit in the main scanning direction, it is possible to use an ink unit (the ink cartridge, or the like) with a simple configuration, meaning that it is possible to achieve a reduction in cost. Furthermore, according to one aspect of the invention, even in the event that a problem such as a clogging of the nozzle occurs, it being possible to resolve it by replacing only the ink cartridge, there is no need to replace the expensive recording head unit. Also, as heat is not used, there is a superior advantage such as there being a wide range of choice of ink. 
     Also, according to one aspect of the invention, as a color printing is possible with one recording head (piezoelectric body unit), a color printing is possible using a simple method, and a reduction in cost is possible. 
     Furthermore, according to one aspect of the invention, as an ink cartridge of a color not needed for the printing is left set aside in a place for setting aside, and does not need to be moved, there is an advantage in that it is possible to continue a capping for longer, and it is possible to obtain a more stable printing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic sectional diagram showing one embodiment of an acoustic ink jet printer according to the invention; 
         FIG. 2  is an outline diagram showing a configuration of a recording head included in the acoustic ink jet printer according to the invention; 
         FIG. 3  is an operational illustration showing a condition of the recording head of  FIG. 2  seen from a paper side; 
         FIG. 4  is an operational illustration showing a condition of the recording head of  FIG. 2  seen from the paper side; 
         FIG. 5  is an operational illustration showing a condition of the recording head of  FIG. 2  seen from the paper side; 
         FIGS. 6A to 6C  are illustrations for illustrating a spattering of ink; 
         FIG. 7  is a diagram showing a modification example of the acoustic ink jet printer according to the invention; 
         FIG. 8  is a diagram showing a further separate modification example of the acoustic ink jet printer according to the invention; 
         FIGS. 9A and 9B  are outline diagrams of a recording head for illustrating another embodiment of the acoustic ink jet printer according to the invention; 
         FIG. 10  is an operational illustration showing a condition of the recording head of  FIGS. 9A and 9B  seen from a paper side; 
         FIG. 11  is a diagram of  FIG. 10  seen from a direction of an arrow a; 
         FIGS. 12A to 12C  are diagrams for illustrating a movement of the recording head of  FIGS. 9A ,  9 B, and  10 ; 
         FIGS. 13A to 13C  are outline diagrams showing a condition of the recording head seen from the paper side; 
         FIGS. 14A and 14B  are illustrations for illustrating another embodiment of the acoustic ink jet printer according to the invention; 
         FIGS. 15A and 15B , showing another embodiment of the acoustic ink jet printer according to the invention, are diagrams for illustrating a case of colorization; and 
         FIGS. 16A and 16B , showing still another embodiment of the acoustic ink jet printer according to the invention, are illustrations illustrating a further separate modification example of the case of colorization. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 to 6C  show a first embodiment of an acoustic ink jet printer according to the invention. 
     Herein, in the diagrams, in an acoustic ink jet printer, using an acoustic ink jet recording method, to which the invention is applied, ink droplets are selectively spattered from a nozzle of a recording head onto recording paper, compiling a recording pattern on the recording paper. 
       FIG. 1  shows a schematic sectional diagram of the acoustic ink jet printer according to the invention. 
     That is, the acoustic ink jet printer is configured of, basically, a paper supply unit A, a recording unit B, and a paper ejection unit C. 
     The paper supply unit A, being configured of a paper supply cassette  1  and a paper supply roller  2 , supplies paper P to the recording unit B in response to a paper supply control signal sent from an unshown central calculation device. 
     The recording unit B is configured of a conveyor roller A 3 , a conveyor roller B 7 , a platen roller  4 , and a recording head  5 . A serial type is employed for the recording head  5 . Ink I is spattered toward the paper P from the recording head  5  in accordance with printing data, and a recording is carried out. Ink is supplied as necessary to the recording head  5  from an ink tank (not shown). The paper P on which the recording in the recording unit B is completed heads toward the paper ejection unit C due to a rotation of the conveyor roller B 7 . 
     In the paper ejection unit C, the paper P on which the recording is completed is stacked on a paper ejection tray  8 . 
       FIGS. 2 to 6C  show a configuration of the recording head  5 . 
     The recording head  5  is configured of a recording head unit  5   a  (that is, a piezoelectric body unit) and an ink cartridge  5   b . Herein, the recording head unit  5   a  (that is, the piezoelectric body unit) is fixed at a size such that a recording can be carried out over the whole width of the paper (in a main scanning direction) in the recording unit B. 
     The ink cartridge  5   b , being disposed in contact with the recording head unit  5   a  (that is, the piezoelectric body unit) as a unit holding the ink, is disposed in a condition in which it can move, by means of an unshown guide rod, timing belt, and drive motor, on the recording head unit  5   a  in a paper width direction (the main scanning direction). A coupling material  13  being applied between the recording head unit  5   a  (that is, the piezoelectric body unit) and the ink cartridge  5   b , an ultrasonic wave generated in the recording head unit  5   a  (that is, the piezoelectric body unit) can be transmitted to the ink cartridge  5   b.    
     The recording head unit  5   a , as the piezoelectric body unit, is configured of a glass substrate  9 , a common electrode  12  extended in the main scanning direction, piezoelectric bodies  11 , and segment electrodes  10 , a multiple of which are formed at predetermined intervals in the main scanning direction corresponding to recording pixels. Herein, the piezoelectric body  11  being disposed in a form in which it is sandwiched between the common electrode  12  and segment electrode  10 , a material exhibiting a piezoelectric property, such as lead zirconate titanate (PZT) or zinc oxide (ZnO), is used. The coupling material  13  is configured of an material exhibiting an ultrasonic wave transmission capability, such as glycerin or silicon oil. 
     Also, the ink cartridge  5   b  is such that, the ink I being loaded into an ink reservoir inside a casing, ink is spattered from an aperture  15 . 
     That is, due to an electric field generated between the segment electrode  10  and common electrode  12  when a printing signal based on recording information is applied to the segment electrode  10  under the control of the unshown central calculation device, the piezoelectric body  11  sandwiched between the two electrodes vibrates, and an ultrasonic wave is generated. The ultrasonic wave generated is transmitted through the glass substrate  9 , and via the coupling material  13 , to the ink loaded into the ink reservoir inside the ink cartridge  5   b . In the following description, each pixel unit acoustic energy generating unit configured by the common electrode  12  and segment electrode  10  sandwiching the piezoelectric body  11  may be called an acoustic energy generating element. 
     Then, as shown in  FIGS. 6A to 6C , an ink meniscus is formed at the aperture  15  of the ink cartridge  5   b  by a radiation pressure occurring due to the ultrasonic wave emitted from the acoustic energy generating element and transmitted to the ink cartridge  5   b , and the ink I is spattered. 
       FIGS. 3 to 5  show a condition of the recording head  5  seen from the paper P side. For the sake of the description, the coupling material  13  is omitted from the diagrams. 
     Herein, the ink cartridge  5   b  is installed in such a way that it can move on the recording head unit  5   a.    
     Then, as shown in  FIG. 3 , the ink cartridge  5   b  starts moving in the direction of a main scanning direction arrow i in response to the printing signal. 
     On the ink cartridge  5   b  moving to a position in which is disposed an acoustic energy generating element at which printing is necessary, a voltage is applied to the segment electrode  10  and, as well as an ultrasonic wave being generated by the piezoelectric body  11 , the ultrasonic wave is transmitted to the ink cartridge  5   b , and the ink I is spattered from the aperture  15  of the ink cartridge  5   b.    
     As shown in  FIG. 4 , when the ink cartridge  5   b  moves further and arrives at a position of an acoustic energy generating element at which a recording is necessary, a voltage is applied to the segment electrode  10 , and the recording is performed. By repeating this operation, the main scanning direction printing is completed. 
     On the paper moving one dot&#39;s worth in a sub-scanning direction, the ink cartridge  5   b  again carries out a recording in the direction of a main scanning direction arrow ii, as shown in  FIG. 5 . By repeating this operation, it is possible to record by spattering ink on a necessary portion of the paper, thus completing the printing. 
     In this way, with the recording head unit (the piezoelectric body unit)  5   a  in a fixed condition, it is possible to carry out a recording simply by moving the ink cartridge  5   b.    
     In the event that, when the ink inside the ink cartridge  5   b  decreases and the recording becomes impossible, the necessity of replacing the ink cartridge  5   b  arises, it is sufficient to replace only the ink cartridge  5   b.    
     As a heretofore known ink jet printer using a piezoelectric body is one which utilizes a deformational displacement of the piezoelectric body, the structure of the ink tank is complex due to the disposition of a pressure chamber, or the like, but according to the invention, as the ink is spattered due to a radiation pressure of a generated ultrasonic wave, the structure of the ink tank is simple. Furthermore, even in the event that a problem such as an ink clogging occurs, it being sufficient to replace only the ink cartridge  5   b , with no need to replace the expensive recording head unit  5   a , a reduction in cost results. 
     Also, with a heretofore known ink jet printer utilizing a heater, there has been a problem in that the range of choice of ink materials is narrow because of the heater reaching a high temperature, but as heat is not utilized in the invention, there is a benefit in that this kind of drawback is eliminated, and any kind of ink material can be used. 
     According to the heretofore described configuration, as it is possible to use the ink cartridge  5   b  with the simple configuration, a reduction in cost results, and also, even in the event that a problem occurs, there is no need to replace the expensive recording head. Furthermore, as the heretofore known kind of heat is not used, there is an advantage in that there is a wide range of choice of ink materials. 
     In the heretofore described embodiment, a case is shown in which the common electrode  12  and segment electrodes  10  are disposed in one row but, the invention not being limited to this, it is also possible to increase the number of nozzles by disposing the common electrode  12  and segment electrodes  10  in a plurality of rows, as shown in  FIG. 7 . Then, by so doing, an increase in printing speed is possible. 
     Also, as shown in  FIG. 8 , it is also possible to connect the ink tank  6  to the ink cartridge  5   b , and supply ink. In this case, even in the event that the ink decreases, it is sufficient to replenish the ink in the ink tank  6 . 
       FIGS. 9A to 12C  show another embodiment of the acoustic ink jet printer according to the invention. 
     Herein, in this embodiment, a description will be given of a case in which, although a detailed depiction is omitted from the diagrams, the platen roller  4  and recording head  5  in the outline diagram of  FIG. 1  in the previously described embodiment are disposed in reverse. 
       FIGS. 9A and 9B  show a structure of the recording head unit  5   a.    
     The recording head unit (the piezoelectric body unit)  5   a  is fixed at a size such that a recording can be carried out over the whole width of the paper (in the main scanning direction) in the recording unit B. An electrode layer  12 E, and a coupling material  13 , are configured on the glass substrate  9 , as shown in  FIG. 9A . 
       FIG. 9B  is a diagram in which, for the sake of the description of the electrode layer  12 E, the coupling material  13  is omitted. 
     The electrode layer  12 E is configured of the common electrode  12  extended in the main scanning direction, the piezoelectric bodies  11 , and the segment electrodes  10 , a multiple of which are formed at predetermined intervals in the main scanning direction corresponding to the recording pixels. A voltage including a resonance frequency of the piezoelectric body  11  necessary for a printing is applied to the segment electrode  10 . Due to an electric field generated between the segment electrode  10  and common electrode  12 , the piezoelectric body  11  disposed between the segment electrode_ 10  and common electrode  12  resonates, and an ultrasonic wave is generated. 
     The recording head unit (the piezoelectric body unit)  5   a  is disposed penetrating the ink cartridge  5   b , as shown in  FIG. 10 . The ink cartridge  5   b  is disposed in a condition in which it can move, by means of an unshown guide rod, timing belt, and drive motor, in response to printing information, in the paper width direction (the main scanning direction), while passing the recording head  5   a  through the interior of the ink cartridge  5   b.    
       FIG. 11  shows the recording head  5  seen from the direction of an arrow a of  FIG. 10 . 
     The recording head unit  5   a  is penetrating the sides of the ink cartridge  5   b . A structure is such that, silicon rubber  14  being disposed in the penetrated portion of the ink cartridge  5   b , a sealing is done so that the ink inside the ink cartridge  5   b  does not leak. 
     The ink I being loaded inside the ink cartridge  5   b , ink is spattered from the aperture  15  in accordance with printing data, and a printing is carried out on the paper P. 
     Due to an electric field generated between the segment electrode  10  and common electrode  12  when a printing signal based on recording information is applied to the segment electrode  10  under the control of the unshown central calculation device, the piezoelectric body  11  sandwiched between the two electrodes resonates, generating an ultrasonic wave. The ultrasonic wave generated is transmitted through the glass substrate  9 , and applies a radiation pressure generated by the ultrasonic wave to the ink on the glass substrate  9 . 
       FIGS. 12A to 12C  are diagrams schematically showing behavior when the ink is spattered. 
     As shown in  FIG. 12B , a meniscus is formed at the aperture  15  of the ink cartridge  5   b  by the radiation pressure generated, after which the ink I is spattered, as shown in  FIG. 12C . 
       FIGS. 13A to 13C  show a condition of the recording head  5  seen from the paper P side. Herein, the ink cartridge  5   b  is installed in such a way that it can move in the main scanning direction while passing the recording head unit  5   a  through its interior. 
     As shown in  FIG. 13A , the ink cartridge  5   b  starts moving in the direction of the main scanning direction arrow i in response to the printing signal. On the ink cartridge  5   b  moving to a position of an acoustic energy generating element at which printing is necessary, a voltage is applied to the segment electrode  10  and, on an ultrasonic wave being generated by the piezoelectric body  11  resonating, a radiation pressure is generated in the ink inside the ink cartridge  5   b , and ink is spattered from the aperture  15 . As shown in  FIG. 13B , when the ink cartridge  5   b  moves further and arrives at a position of an acoustic energy generating element at which a recording is necessary, a voltage is applied to the segment electrode  10 , and the recording is performed. By repeating this operation, the main scanning direction printing is completed. 
     On the paper moving one dot&#39;s worth in the sub-scanning direction by means of a conveyor mechanism, the ink cartridge  5   b  again carries out a recording in the direction of the main scanning direction arrow ii, as shown in  FIG. 13C . By repeating this operation, it is possible to record by scattering ink on a necessary portion of the paper, thus completing the printing. 
     In this way, with the recording head unit  5   a  in a fixed condition, it is possible to carry out a recording simply by moving the ink cartridge  5   b  in the main scanning direction. 
     In the event that, when the ink inside the ink cartridge  5   b  decreases and the recording becomes impossible, the necessity of replacing the ink cartridge arises, it is sufficient to replace only the ink cartridge  5   b . That is, in order to replace the ink cartridge  5   b , the ink cartridge  5   b  is moved in the direction of an arrow iii, and removed from the recording head unit  5   a , as shown in  FIG. 13A . 
     In the case of loading a new ink cartridge  5   b , it is loaded in such a way that the recording head unit  5   a  is inserted into a through hole opened in the center of the ink cartridge  5   b.    
     By means of this kind of configuration too, in the same way as with the heretofore described embodiment, various superior effects are achieved, as follows. 
     That is, as a heretofore known ink jet printer using a piezoelectric body is one which utilizes a deformational displacement of the piezoelectric body, the structure of the ink tank is complex due to the formation of a microchannel, or the like, in the ink tank in order to dispose a pressure chamber, but according to the invention, as the ink is spattered due to a radiation pressure of an ultrasonic wave generated by the resonance of the piezoelectric body, the pressure chamber is not needed. Consequently, the structure of the ink tank is simple. 
     Also, as the ink is caused to come into direct contact with the recording head unit  5   a , the coupling material for the ultrasonic wave transmission is not needed, meaning that a simplification and reduction in cost of the apparatus result. Furthermore, even in the event that a problem such as an ink clogging occurs, it being sufficient to replace only the ink cartridge  5   b , with no need to replace the expensive recording head unit  5   a , a reduction in cost results. 
     Also, with a heretofore known ink jet printer utilizing a heater, there has been a problem in that the range of choice of ink materials is narrow because of the heater reaching a high temperature, but as heat is not utilized in the invention, there is a benefit in that any kind of ink material can be used. 
     Then, as it is possible, with this configuration too, to use an ink cartridge with a simple configuration, a reduction in cost results. Furthermore, even in the event that a problem such as a clogging of the nozzle occurs, as it is possible to configure with only the ink cartridge, there is no need to replace the expensive recording head. Also, as heat is not used, there is an advantage in that there is a wide range of choice of ink. 
     With this embodiment too, in the same way as with the heretofore described embodiment, it is possible to increase the number of nozzles by disposing the common electrode and segment electrodes in a plurality of rows. 
     Also, it is also possible to connect the ink tank  6  to the ink cartridge  5   b.    
     Also, as shown in  FIG. 14A , the invention is applicable with a line head too. 
     Herein, in this kind of configuration, there is an advantage in that, as it is sufficient to move the ink cartridge  5   b  from the recording head  5   a , as in  FIG. 14B , and replace only the ink cartridge  5   b  in the event that a problem such as a nozzle clogging occurs, a reduction in cost results. 
       FIGS. 15A and 15B  show a case of carrying out a color printing with the apparatus configuration according to the invention. 
     That is, a plurality of ink cartridges  5   b  are disposed on the recording head unit  5   a , as shown in  FIG. 15A . 
     For example, in a case of carrying out a printing in the four colors yellow, magenta, cyan, and black, four ink cartridges  5   bbk ,  5   bm ,  5   bc , and  5   by  are disposed aligned on the recording head unit  5   a , as shown in  FIG. 15A . The ink cartridges  5   bbk ,  5   bm ,  5   bc , and  5   by  move in the main scanning direction, in accordance with  5  printing data, as shown in  FIGS. 15A and 15B . 
     Then, on the ink cartridges  5   bbk ,  5   bm ,  5   bc , and  5   by  arriving above a segment electrode  10  at which printing is necessary, a voltage is applied to the segment electrode  10  in accordance with the printing data, an ultrasonic wave is generated and, for example, when carrying out a black printing, it is possible to carry out a spattering of ink from the ink cartridge  5   bbk.    
     Also, in the event of printing with another color at the same segment electrode  10 , in the case of, for example, magenta, the voltage is applied to the segment electrode  10  when the ink cartridge  5   bm  has moved to the position of the acoustic energy generating element, and it is possible to carry out a spattering of the ink I. As the four colors of ink cartridge  5   bbk ,  5   bm ,  5   bc , and  5   by  move together, it is possible to carry out printing in the four colors with one recording head unit  5   a.    
     Then, with a heretofore known ink jet printer, it has been necessary to prepare a plurality of colors&#39; worth of recording heads when carrying out a printing in a plurality of colors, but according to the invention, as a color printing is possible with the one recording head unit  5   a , the color printing is possible using a simple method, and a reduction in cost is possible. 
     Furthermore, as shown in  FIGS. 16A and 16B , by providing a place and method for setting aside the ink cartridges  5   bbk ,  5   bm ,  5   bc , and  5   by , it is possible to dispose only a necessary color on the recording head unit  5   a.    
     Also, a capping of the ink cartridges  5   bbk ,  5   bm ,  5   bc , and  5   by  is carried out when not printing in order to prevent the ink from drying. In the case of the invention, as it is possible, even during printing, to continue the capping, in the place for setting aside, of an ink cartridge of a color not needed for the printing, it being possible to prevent the drying of the ink, it is possible to prevent an occurrence of the ink clogging, and it is possible to provide a stable printing. 
     According to the heretofore described configuration, as a color printing is possible with one recording head, a color printing using a simple method is possible, and a reduction in cost is possible. Also, as there is no need to move an ink cartridge of a color not needed for the printing from the place for setting aside, it is possible to continue the capping for longer, and it is possible to obtain a more stable printing. 
     The invention not being limited to the structures described in the heretofore described embodiments, it goes without saying that the shape, structure and the like of each portion configuring the acoustic ink jet printer may be appropriately modified or altered.