Abstract:
An inkjet recording device includes an ink cartridge receiving unit configured to receive an ink cartridge, an inkjet head configured to eject ink, an ink passage configured to transport the ink from the ink cartridge to the inkjet head, a detecting unit configured to detect a type of ink cartridge received in the ink cartridge receiving unit, a waste ink collection unit including an absorber configured to absorb the ink, a discharging unit configured to discharge the ink remaining in the ink passage at one of a first discharging rate and a second discharging rate, and a controller configured to control the discharging unit to discharge an amount of ink. The controller is configured to control the discharging unit to discharge ink at one of the first discharging rate and the second discharging rate corresponding to the type of the ink cartridge detected by the detecting unit.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Japanese Patent Application No. 2007-340693, filed Dec. 28, 2007, the entire subject matter and disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an inkjet printer. 
     2. Description of the Related Art 
     A conventional inkjet printer is supplied ink by mounting an ink cartridge in an ink cartridge receiving unit. The inkjet printing apparatus is designed to perform printing by using a predetermined suitable type of ink, e.g., a pigment ink, a dye ink, or the like, contained in the ink cartridge. If an ink cartridge containing an unsuitable ink is mounted, a risk of clogging may increase. Therefore, it is preferable to use the ink cartridge containing the predetermined type of ink. 
     In a known inkjet printer, when an unexpected ink cartridge is mounted, the known inkjet printer discharges a large amount of ink in a maintenance operation, and this accelerates the ink discharge to a high speed. 
     In a known inkjet printer, ink that is discharged by a maintenance operation is collected by a collection unit, e.g., a waste ink tank. A porous member, e.g., a sponge, is provided inside such a tank, and waste ink is absorbed by the sponge. In this case, if the type of the waste ink is known, a total amount of waste ink is determined according to the type of the waste ink, on the basis of a discharge amount of waste ink per unit time, and a time for which waste ink should be discharged. Ink absorption ability, e.g., ink absorption rate, of the sponge is determined on the basis of these parameters. If no consideration is given to the ink absorption ability of the sponge and an amount of waste ink beyond the ink absorption ability is discharged, the waste ink may not be absorbed by the sponge and may overflow the waste ink tank into the printer, which may damage a circuit board or other portion of the printer. 
     If the above parameters are known, the discharge amount of waste ink per unit time can be increased to a value that is almost equal to the waste ink absorption rate of the sponge. Therefore, the discharge amount of waste ink per unit time can be set so that the time taken until completion of discharge of waste ink is made shortest, e.g., the discharge amount of waste ink per unit time is maximized, according to the waste ink absorption rate. Nevertheless, if a large amount of ink of an unsuitable ink cartridge, e.g., ink whose material properties are unsuitable is discharged, the discharge amount per unit time may exceed the maximum waste ink absorption rate, because a rate at which the ink having unsuitable material properties is absorbed by the sponge may not be assumed. The waste ink may overflow the waste ink tank into the printer and damage a circuit board or other portion of the printer. 
     SUMMARY OF THE INVENTION 
     A need has arisen to provide an inkjet recording device which may discharge a larger amount of ink to prevent or reduce ink coagulation due to mixing of different types of inks and may prevent or reduce the overflow of the waste ink tank. To attain the above need, the invention provides an inkjet recording device comprising an ink cartridge receiving unit configured to receive an ink cartridge and an inkjet head configured to eject an ink. The inkjet recording device further comprising an ink passage configured to transport the ink from the ink cartridge to the inkjet head and comprising a detecting unit configured to detect a type of the ink cartridge received in the ink cartridge receiving unit. The inkjet recording device still further comprising a waste ink collection unit comprising an absorber configured to absorb the ink, and comprising a discharging unit configured to discharge ink remaining in the ink passage at one of a first discharging rate and a second discharging rate. Moreover, the inkjet recording device comprising a controller configured to control the discharging unit to discharge an amount of the ink. The controller is configured to control the discharging unit to discharge ink at one of the first discharging rate and the second discharging rate corresponding to the type of the ink cartridge detected by the detecting unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing an appearance of an inkjet printer according to an embodiment of the invention. 
         FIG. 2  is a block diagram relating to information processing of the inkjet printer according to an embodiment of the invention. 
         FIG. 3  is a flowchart of a process which is executed after replacement of an ink cartridge according to an embodiment of the invention. 
         FIG. 4  shows the configuration of a portion of the inkjet printer, relating to a flushing operation according to an embodiment of the invention. 
         FIG. 5  shows the configuration of a portion of the inkjet printer, relating to a purge operation according to another embodiment of the invention. 
         FIG. 6  shows an example alarm message according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view showing an inkjet printer  1  according to an embodiment of the invention. 
     In the inkjet printer  1 , ink cartridges  70  may contain respective inks, and may be mounted in an ink supply unit  2 . As shown in  FIG. 1 , the ink supply unit  2  comprises a lid, and the ink cartridges  70  may be mounted into the ink supply unit  2  by opening the lid. Various manipulations for cartridge replacement, etc., may be performed using an operating panel  4 , and various messages relating to a printing operation may be displayed on a display unit  5 . Printing sheets may be supplied to a sheet tray  3 . 
       FIG. 2  is a block diagram relating to information processing of the inkjet printer  1 . A control unit  100  may comprise a CPU  101  which controls processing, a ROM  102  in which control programs may be stored, a RAM  103  where a program and data may be developed, and an Electrically Erasable Programmable Read-Only Memory(“EEPROM”)  104  which may be a nonvolatile memory. The control unit  100  thus may control the entire printer  1 . 
     Commands that may be sent from the control unit  100  may be transmitted, via a bus  107 , after being converted with an ASIC  130  into forms suitable for them, to circuits and boards, e.g., a head control board  33  for controlling an inkjet head  8 , drive circuits  81  and  82  for driving motors, a scanner unit  86 , the operating panel  4  for manipulating the inkjet printer  1 , a rotary encoder  83  for measuring a rotation speed of rollers, a linear encoder  84  to be used for moving a carriage  38  correctly, and ID reading units  51 , e.g., an ink cartridge type detecting unit, e.g., a detecting unit, for reading identifications, e.g., IDs of IC chips, e.g., identification portions, such as memory chips, that may be mounted on the ink cartridges, respectively. 
     The CR motor  79  and the LF motor  80  may drive the carriage  38  and sheet feed rollers  20 , on the basis of signals that are output from the drive circuits  81  and  82 , respectively. Signals that may be output from the circuits and boards, such as the head control board  33 , the drive circuits  81  and  82 , the scanner unit  86 , the operating panel  4 , the rotary encoder  83 , the linear encoder  84 , and the ID reading unit  51 , may be transmitted to the control unit  100  after being converted with the ASIC  130  into signals having timing that may be suitable for the bus  107 . 
       FIG. 4  outlines a configuration, relating to a printing operation using the inkjet head  8 , and a maintenance operation of the inkjet printer  1  according to an embodiment. As shown in  FIG. 4 , a printing sheet P. e.g., a printing medium, may be transported in a horizontal direction as the sheet feed rollers  20  rotate. In a state that the printing sheet P is located under the inkjet head  8 , ink droplets may be ejected from the nozzles of the inkjet head  8 , in a printing operation. In  FIG. 4 , the printing sheet P is oriented horizontally. 
     Ink tubes  60 , e.g., ink passages, may extend from the inkjet head  8  to respective ink cartridge receiving units  50 . Ink cartridges  70  may be mounted in the respective ink cartridge receiving units  50  in a replaceable manner, and inks may be supplied from the ink cartridges  70  to the inkjet head  8  via the ink tubes  60 . The ink cartridge receiving units  50  may be disposed inside the lid of the above-mentioned ink supply unit  2 . As shown in  FIG. 4 , the ink cartridges  70 , the ink cartridge receiving units  50 , and the ink tubes  60  may be provided in one or more of, e.g., four, systems, which may correspond to one or more of, e.g., four, respective colors, e.g., black, yellow, cyan, and magenta. 
     As shown in  FIG. 4 , the inkjet head  8  may transfer together with the carriage  38  in the horizontal direction, that is, perpendicularly to the transport direction of the sheet P. The movement direction of the carriage  38  may be restricted by a guide rail (not shown). This movement of the inkjet head  8  may enable printing on the entire surface of the sheet P. The movement of the inkjet head  8  and the ejecting of inks from the inkjet head  8  may be controlled by commands that are output from the control unit  100 . 
     Furthermore, the inkjet head  8  and the carriage  38  may be moved in the same manner, to outside the range of the sheet P, such that inkjet head  8  and carriage  38  may be located over a waste ink tank  40 , e.g., an ink collection unit. As described herein, when the inkjet head  8  and carriage  38  are in this position, an ink discharge may be performed by a flushing operation at the time of ink cartridge replacement. In this state, ink may be ejected toward the inside of the waste ink tank  40  from the inkjet head  8 , which may be moved to over a discharge mouth  41  located at the top of the waste ink tank  40 . A porous member  42 , e.g., an absorber, made of sponge, felt, cellulose, or the like, may be disposed inside the waste ink tank  40 . Since the porous member  42  may be disposed inside the waste ink tank  40 , discharged ink may be absorbed by the porous member  42  and may be held stably. 
     With the above apparatus configuration, in an embodiment, maintenance with ink discharge may be performed by a flushing operation when an ink cartridge  70  is replaced. In the inkjet printer  1 , since ink in the vicinity of the aperture of each nozzle of the inkjet head  8  may be in direct contact with the air, ink solvent may volatilize, and dye or pigment may be deposited on the aperture surface, which may increases the ink viscosity. The flushing operation may be an operation of ejecting out ink of increased viscosity from the nozzles. 
     For example, the flushing operation may be performed regularly during printing operations, or when a lack of dots occurs during printing. With the configuration of  FIG. 4 , as described above, an ordinary flushing operation may be performed in a state in which the inkjet head  8  has been moved to over the discharge mouth  41  of the waste ink tank  40 . In an embodiment, an ink discharge also may be performed by a flushing operation when an ink cartridge  70  is replaced, to avoid a mixing of different types of inks. 
       FIG. 3  is a flowchart of a process which may be executed after replacement of an ink cartridge  70  according to an embodiment of the invention. The steps of the process may be executed in response to commands sent from the control unit  100 . 
     At step S 100 , the inkjet printer  1  may recognize a start of cartridge replacement work, e.g., detects opening of the lid of the ink supply unit  2  or recognizes removal of an ink cartridge  70 . At step S 200 , the inkjet printer  1  may reset the remaining amount of ink. 
     At step S 300 , the control unit  100  may instruct the ID reading unit  51  to read an ID of a latest ink cartridge  70 , e.g., to detect the type of the ink cartridge received by the ink cartridge receiving unit  50 . In response, the ID reading unit  51  reads electronic information, e.g., identifying information, such as an ID, that may be stored in an electronic information storing chip  71 , e.g., a memory chip, of the ink cartridge  70 . As shown in  FIG. 4 , ID reading units  51  may be provided in respective ink cartridge receiving units  50 . 
     The reading of electronic information which may be performed at step S 300 , may be a process of obtaining binary information, which may indicate a type of the ink cartridge  70  mounted in the corresponding ink cartridge receiving unit  50 . The binary information may indicate not only the type of the ink cartridge  70  but also “verifiable” or “unverifiable.” “Verifiable” may mean that electronic information may be read from the electronic information storing chip  71 , and that read-out information may correspond to predetermined electronic information that may be specific to the printer type that was registered by the manufacturer. On the other hand, “unverifiable” may mean that electronic information may not be read from the electronic information storing chip  71 , or that electronic information may be read out, but the read out electronic information may not correspond to the predetermined electronic information that may be specific to the printer type that was registered by the manufacturer. The predetermined electronic information that is specific to the printer type may be registered such that that the read-out information may not correspond to the predetermined electronic information when the electronic information may not be read from the electronic information storing chip  71 . Another reason the cartridge may be “unverifiable,” e.g., that electronic information may not be read from the electronic information storing chip  71 , may be the case that no electronic information storing chip  71  is mounted on the ink cartridge  70 . 
     At step S 400 , the control unit  100  may determine whether the ink cartridge  70  that has been mounted this time, e.g., the ink cartridge received by the ink cartridge receiving unit  50 , or the ink cartridge detected by the detecting unit, is of the same type as the preceding ink cartridge  70 . “Of the same type” may mean that both of the latest ink cartridge  70  and the preceding ink cartridge  70  have read out information that corresponds to the predetermined electronic information. On the other hand, “not of the same type” may mean that the read out information of at least one of the latest ink cartridge  70  and the preceding ink cartridge  70  may not correspond to the predetermined electronic information. If both the latest ink cartridge  70  and the preceding ink cartridge  70  are “unverifiable,” then control unit  100  may determine that the cartridges are “not of the same type,” even if the latest ink cartridge  70  and preceding ink cartridge  70  are the same type of “unverifiable” ink cartridge. 
     Control unit  100  may store information of whether the read-out information of preceding ink cartridge  70  is “verifiable” or “unverifiable” because of a prior execution of step S 510 , which will be described herein. If the latest ink cartridge  70  is of the same type as the preceding one, e.g., “YES” at Step S 400 , the process may move to step S 600 . If the latest ink cartridge  70  is not of the same type as the preceding one, e.g., “NO” at Step S 400 , the process may move to step S 410 . At Step S 600 , a cartridge replacement discharge, which will be described in more detail herein, may be performed. Then, the execution of the process may be completed. A cartridge replacement strong discharge may be performed at step S 410  and the following steps, which will be described in more detail herein. 
     The cartridge replacement discharge and the cartridge replacement strong discharge will be described herein. The cartridge replacement discharge may be processing for, for example, discharging ink into, and ejecting air bubbles from, the ink tube  60  and the nozzles of the inkjet head  8 , by performing a flushing operation as described above when a cartridge  70  is replaced. 
     As described above, if both of the preceding ink cartridge  70  and the latest ink cartridge  70  correspond to the predetermined electronic information, e.g., that it may be confirmed that the preceding ink and the latest ink may be the same ink, then the process may be at Step S 600 . Therefore, a mixing of different types of inks may not occur in the ink tube  60 . Therefore, in the cartridge replacement discharge which may be performed at step S 600 , a smaller amount of ink may be discharged than in the cartridge replacement strong discharge, which will be described in more detail herein. 
     Next, the cartridge replacement strong discharge will be described. As described above, if one or both of the preceding ink cartridge  70  and the latest ink cartridge  70  may not correspond to the predetermined electronic information, e.g., the ink in the ink tube  60  may be of a different type than the ink in the latest ink cartridge  70 , e.g., a state of mixing of different types of inks. Specifically, since the type of the “unverifiable ink” may be unknown, the two inks likely may be of different types. The ink that remained in the ink tube  60  when a cartridge  70  was replaced may come into contact with the ink in a latest ink cartridge  70 . If the inks are brought into contact with each other, the inks may begin to diffuse into each other. As a result, if the two inks have different ink properties, the inks may coagulate inside the ink tube  60 , which may disrupt a later printing operation. To avoid or reduce this phenomenon, it may be preferable to discharge the ink in the ink tube  60 . 
     Therefore, if it is determined that the latest ink cartridge  70  is of a different type than the preceding ink cartridge  70 , a cartridge replacement strong discharge is performed. The cartridge replacement strong discharge may be an operation that may completely replace at least the ink remaining in the ink tube  60  with the latest ink, to prevent or reduce ink coagulation due to mixing of different types of inks. 
     Therefore, in the cartridge replacement strong discharge, more ink is discharged than in the cartridge replacement discharge described previously. A mixture of different types of inks may also occur outside the ink tube  60 , e.g., in the latest ink cartridge  70 . Therefore, the total amount of discharged ink may be set, for example, as 1 to 1.5 times larger than the capacity of the ink tube  60 . 
     At step S 410 , an alarm message, e.g., to the effect that a large amount of ink may be consumed, relating to the cartridge replacement strong discharge may be displayed. After recognizing the alarm message, if the user agrees to perform a cartridge replacement strong discharge, at Step S 420  the user may indicate his or her intention of agreement, e.g., by depressing an OK button, or by depressing a button corresponding to an OK button on the operating panel  4 , or by clicking on an OK button, or a button corresponding to the OK button that may be included in the alarm message displayed on a terminal that may be connected to the inkjet printer  1 . 
     The display of the alarm message may allow the user to know that a cartridge replacement strong discharge is to be performed after the replacement with the latest ink cartridge  70 .  FIG. 6  shows an example alarm message. If the user&#39;s intention of agreement has been confirmed by, for example, depression of the OK button, at Step S 510 , information indicating whether the latest ink cartridge  70  corresponds to the predetermined electronic information or not, e.g., a type of latest ink cartridge  70 , may be stored in the EEPROM  104 . As described above, the information indicating whether the latest ink cartridge  70  corresponds to the predetermined electronic information may be used at the determining steps S 400  and S 520 , e.g., as a type of previous ink cartridge  70 , at the time of the next ink cartridge replacement. 
     At Step S 520 , it is determined whether the preceding ink previously corresponded to the predetermined electronic information If the preceding ink corresponded to the predetermined electronic information, e.g., “YES” at Step S 520 , the process may move to Step S 530 , e.g., a step of cartridge replacement strong high-speed discharge. If the preceding ink did not correspond to the predetermined electronic information, e.g., “NO” at Step S 520 , the process may move to Step S 540 , e.g., a step of cartridge replacement strong low-speed discharge. In this manner, the cartridge replacement strong discharge may be classified into two types, e.g., the cartridge replacement strong high-speed discharge, and the cartridge replacement strong low-speed discharge. These two types of cartridge replacement strong discharge will be described in more detail herein. 
     The process may reach step S 530 , e.g., the step of cartridge replacement strong high-speed discharge, if the preceding ink cartridge  70  corresponded to the predetermined electronic information, and the latest ink cartridge  70  does not correspond to the predetermined electronic information, as seen from the determining results of steps S 400  and S 520 . Therefore, the ink in the ink tube  60 , which may be the ink of the preceding ink cartridge  70 , may be predetermined ink. On the other hand, the process may reach Step S 540 , e.g., cartridge replacement strong low-speed discharge if the preceding ink cartridge  70  may not correspond to the predetermined electronic information, as seen from the judgment results of steps S 400  and S 520 . Therefore, the ink in the ink tube  60  may not be the predetermined ink. 
     When ink is discharged by the cartridge replacement strong discharge, there may occur an event that ink may not immediately be absorbed by the porous member  42  disposed in the waste ink tank  40 , and ink may overflow the waste ink tank  40 . Since the absorption rate may be determined by the combination of the material of the porous member  42  and the ink composition, if the ink type is known, the absorption rate may be set to such a value that may not cause an ink overflow from the waste ink tank  40 . Nevertheless, if the preceding ink is unknown, then the absorption rate may not be able to be set. Furthermore, in the cartridge replacement strong discharge, the discharge amount may be larger than in an ordinary flushing operation, which may increase the importance of reducing the risk of ink overflow. 
     In view of the above, at Step S 530 , e.g., cartridge replacement strong high-speed discharge, since the composition of the ink in the ink tube  60  may be known, flushing may be performed at a high speed. For example, the term “high speed” may mean a highest speed in a range that may allow ink to be absorbed by the porous member  42 . Fastest discharge rates in such a range that ink can be absorbed by the porous member  42 , which may be employed at Step S 530 , may be determined in advance for respective known inks. As mentioned above, the porous member  42  may be made of a material selected from a variety of materials, e.g., sponge, felt, cellulose, and the like. Therefore, fastest discharge rates, in such a range that ink that may be discharged at Step S 530  may not overflow the waste ink tank  40 , may be determined in advance, with respect to the types of materials which may be used as the porous member  42 . As a further alternative, fastest discharge rates may be determined in advance for combinations of known inks and types of materials of the porous member  42 , in such a range that ink can be absorbed by the porous member  42 . In an embodiment of the invention, such fastest discharge rates may be stored in a memory, e.g., the ROM  102 , and the like, and may employ, at Step S 530 , a discharge rate that may be equal to or lower than an applicable fastest discharge rate. 
     At Step S 540 , e.g., the cartridge replacement strong low-speed discharge, since the composition of the ink in the ink tube  60  may be unknown, flushing may be performed at a lower speed, such that ink may not overflow the waste ink tank  40 . As is understood from the above description, in the cartridge replacement strong high-speed discharge, high-speed flushing may allow a maintenance operation to be performed without forcing the user to wait for a long time. Nevertheless, in the cartridge replacement strong low-speed discharge, low-speed flushing may allow a use of an apparatus in which it is important to avoid overflow of an unknown ink. 
     The level of “low speed” of the cartridge replacement strong low-speed discharge may be varied according to different embodiments of the invention. In an embodiment of the invention, the total flushing time may be set in advance, e.g., to 10 or 15 minutes, or the like. In another embodiment of the invention, two low-speed levels may be set in advance, and the lower low-speed level may be employed before a command for the next print job may be received, and the higher low-speed level may be employed after a command for the next print job may be received. In this embodiment, it may be possible to flexibly accommodate the presence or absence of a print job. 
     The high speed and the low speed of the cartridge replacement strong discharge may be realized by changing the ejecting interval of the flushing operation. Specifically, for example, the flushing operation may be such that a prescribed number of ink droplets are ejected emptily each time. In this example, the time interval between ejecting operations of a prescribed number of ink droplets may be set to be shorter in the case of the cartridge replacement strong high speed discharge, and may be set to be longer in the case of the cartridge replacement strong low-speed discharge. In this case, it may be preferable to use, as a process for ejecting a prescribed number of ink droplets each time, a corresponding process of an ordinary flushing operation, e.g., a flushing operation not related to cartridge replacement, which may allow the system to be made simpler. 
       FIG. 5  shows another embodiment of the invention. Only features which may differ from the previously described embodiment will be described herein. 
     In the embodiment shown in  FIG. 5 , instead of the configuration of  FIG. 4 , a purge operation is performed instead of the flushing operation of the previously described embodiment. In the following embodiment, the purge operation may be a suction purge operation. The suction purge operation may be a maintenance operation in which ink is drawn out of the nozzles of the inkjet head  8 , to remove air bubbles and foreign substances from the nozzles, or to discharge ink into the nozzles. The structure for the suction purge of this embodiment may be replaced by another structure, e.g., the structure for a known pressure purge. 
     In the configuration of  FIG. 5 , a purge mechanism may comprise a cap  45 , a pump  46 , a tube  47 , and a waste ink tank  48 , e.g., another example of an ink collection unit. The cap  45  may be brought into close contact with the inkjet head  8 , and may draw ink using suction force generated by the pump  46 . Drawn-out ink may be collected by the waste ink tank  48  through the tube  47 . The cap  45  may be brought into close contact with the inkjet head  8  by an upward movement from a moving mechanism (not shown). Similarly to the embodiment shown in  FIG. 4 , a porous member made of sponge, felt, cellulose, or the like, may be disposed in the waste ink tank  48 . 
     The process described in  FIG. 3  also may be employed in the current embodiment. With the configuration of  FIG. 5 , if a large amount of ink is discharged at high speed when an ink cartridge  70  is replaced, the ink may not be fully collected by the waste ink tank  48  and, for example, may overflow through the cap  45 . Therefore, similarly to the previously described embodiment, the cartridge replacement strong low-speed discharge, e.g., Step S 540  may be effective to prevent ink overflow in waste ink tank  48 .