Abstract:
A printer having an ink container, an ink jet head, and an ink storage container for temporarily storing ink to be supplied from the ink container to the ink-jet head, the ink storage container having a closable air communicating portion communicating with ambient air. A first ink path connects the ink container to the ink storage container, defines a flow of ink from the ink container to the ink storage container, and is provided with a one-way flow restricting member for permitting only a flow of ink in a direction of discharge from the ink container. A second ink path connects the ink storage container to the ink container and defines a flow of ink for returning an excess amount of ink over a predetermined liquid amount in the ink storage container to the ink container. An opening/closing member opens and closes the air communicating portion to ambient air. A buffer container is provided at a portion of the first ink path between the one-way flow restricting member and the ink storage container and is capable of maintaining a predetermined liquid amount. A transfer member transfers ink from the buffer container and is provided at a portion of the first ink path between the buffer container and the ink storage container.

Description:
This application is a division of application Ser. No. 08/553,867 filed Nov. 6, 1995 now U.S. Pat. No. 5,801,736. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a printer and an ink cartridge to be widely used in POS, factory automation (FA), physical distribution (PD) and so forth, for example, and an ink cartridge to be employed in such printer. More specifically, the invention relates to a printer employing an ink-jet printing system and an ink cartridge to be used with such printer. 
     2. Description of the Related Art 
     Up to now, a label printer utilizing an ink-jet printing system has not been put into practical use. In general sense, advantages of an ink-jet printing are quietness in operation for not contacting with a printing medium, high printing speed, capability of high density printing, easiness of color printing, compactness in overall apparatus and so forth. 
     A paper, such as label, to be used in the label printer is smaller in size in comparison with normal paper, such as A4 paper and so forth, typically used in the office. Therefore, a full-line type printing head can be easily employed as a printing head for the label printer. 
     When the full-line type ink-jet head is employed, special construction different from the case where a normal serial type ink-jet head is employed, in ink recirculation for recovery of ejection, ink supply and so forth. Also, in such ink supply system, when a tube pump is employed as a driving source, derivative problem may be encountered in simplification of drive control. 
     On the other hard, in the ink-jet type label printer, it becomes necessary to appropriately manage ink to be used, including management of ink leakage in the apparatus and so forth. As a system which provides various advantages in ink management or ink supply management, an ink cartridge has been known. Namely, by making an individual cartridge storing the ink detachable with respect to the apparatus by inserting and removing an ink supply needle, the ink cartridge can be replaced with new one when the ink therein is spent out. 
     However, associating with the above-mentioned ink cartridge, problems may encountered in the label printer in management of waste ink and ink leakage upon detaching of the ink cartridge. Also, due to interference between the ink cartridge and the label printer body upon loading of the ink cartridge, a seal formed by an electrically resistant member provided on the ink cartridge for identification and so forth can be damaged. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a printer which can solve various problem derived in an ink supply system as set forth above, and particularly to provide a label printer which can solve the problems in the case where a tube pump is employed. 
     Another object of the present invention is to provide an ink cartridge which is employed in the label printer set forth above and permits appropriate management of waste ink. 
     According to one aspect of the invention, a printer having an ink-jet head ejecting an ink for performing printing on a printing medium, comprises an ink cartridge storing the ink to be supplied to the ink-jet head, ink storage means for temporarily storing the ink to be supplied from the ink cartridge to the ink-jet head, having an atmosphere communication opening and having an ink path for returning an excess amount of ink to the ink cartridge, buffer means connected to the ink cartridge via an ink path having an one-way valve permitting only flow of the ink from the ink cartridge, connected to the ink storage means via an ink path having a tube pump and connected to the ink-jet head via an ink passage having an one-way valve permitting only flow of the ink toward head ink-jet head, for maintaining the ink amount at a predetermined amount, and opening and closing means for opening and closing the atmosphere communication opening of the ink storage means. 
     Here, the printer may further comprise second buffer means connected to the ink-jet head via an ink path and connected to the ink storage chamber via an ink path having a second tube pump, for maintaining the ink amount at the predetermined amount. 
     On the other hand, the tube pump may guide a tube at portions other than a portion where a depression roller of the tube pump acts on the tube. 
     Also, the ink path for returning the excess amount of ink in the ink storage means to the ink cartridge may include a needle unit having a needle communicated with the inside of the ink cartridge associating with loading operation of the ink cartridge, the needle unit having a valve for establishing communication between the inside of the ink cartridge and the needle by loading operation of the ink cartridge. 
     Furthermore, a positional relationship between the ink cartridge and the needle unit upon loading of the ink cartridge may be that a communication opening of the needle penetrates within the ink cartridge and subsequently the valve is opened. 
     Also, the ink path connecting the ink cartridge and the buffer means may include a needle unit having a needle to be communicated with the inside of the ink cartridge associating with loading of the ink cartridge, the needle unit having a valve establishing communication between the ink cartridge and the needle by a suction pressure transmitted via the buffer means by driving of the tube pump. 
     The printer may further comprise means for manually opening and closing the atmosphere communication opening of the ink storage means. 
     Furthermore, the ink cartridge may include an ink storage chamber for storing the ink to be supplied to the ink-jet head and a waste ink storage chamber having an absorbing member for holding and storing the ink discharged from the printer, and the ink storage chamber and the waste ink storage chamber are formed integrally, and the waste ink storage chamber has two stage construction. 
     Also, the printer may further comprise a cartridge receptacle chamber, to which the ink cartridge is detachably loaded, and having a shutter member pivotably provided at an insertion opening for the ink cartridge and engaging with the outer surface of the ink cartridge when the ink cartridge is inserted for loading, the ink cartridge being provided with a resistant member depending upon information relating the ink cartridge, on the outer surface thereof, and the shutter member is formed into a configuration having a cut-out portion so as not to interfere with the resistant member upon engagement with the outer surface of the ink cartridge, 
     It should be noted that the ink-jet head may eject the ink by generating a bubble of the ink utilizing a thermal energy and ejecting the ink by generation of the bubble. 
     According to the second aspect of the invention, an ink cartridge to be employed in a printer performing printing on a printing medium, comprises an ink storage chamber for storing an ink to be supplied to the printer, a waste ink storage chamber storing the ink discharged from the printer and having an absorbing member holding the ink, the ink storage chamber and the waste ink storage chamber being formed integrally and the waste ink storage chamber has two stage structure. 
     The waste ink storage chamber may be provided with a detection sensor for detecting presence of the ink. 
     Also, the detection sensor may be located at an upper stage of the two stage structure and defines by a given height of wall, in which the absorbing member is not present. 
     Furthermore, an ink inlet portion of the waste ink storage chamber may be provided at the lower stage of the two stage structure. 
     Also, ink supply for the printer and introduction of discharge of ink from the printer may be performed a supply needle inserted within the ink cartridge, and an absorbing member is provided at least at the portion where the supply needle is inserted. 
     According to the third aspect of the invention, an ink cartridge for storing an ink to be used by a printer for performing printing on a printing medium, characterized in that ink supply for the printer and introduction of discharge of ink from the printer is performed a supply needle inserted within the ink cartridge, and an absorbing member is provided at least at the portion where the supply needle is inserted. 
     With the present invention, when the ink is forcedly fed from the ink storage chamber to the ink-jet head by means of the tube pump, influence of the pulsation of the pressure induced by the tube pump can be successfully avoided. Also, since interference between the depression roller and the tube in the tube pump can be successfully avoided, the problem of cutting of the tube by the depression roller can be prevented. Also, associating with the detachable ink cartridge, connection of the ink cartridge and the ink supply system can be performed without causing leakage. Furthermore, since the atmosphere communication opening of the ink storage chamber can be opened and closed by manual operation, leakage of the ink through the atmosphere communication opening during transportation can be successfully avoided. As a result, the printer having the ink supply system which can perform satisfactory ink supply can be provided. 
     In addition, the waste ink flowing into the ink cartridge can be maintained therein. Also, since the presence of the ink is detected only when the waster ink chamber is filled with the waster ink, error in detecting the waste ink with accumulation of small amount of the waste ink to cause erroneous exchange of the ink cartridge may not be caused. Furthermore, upon piercing and removing of the supply needle associating with loading and unloading of the ink cartridge, since the ink adhering on the supply needle can be removed by the absorbing member, leakage of the ink will not be caused. In addition, upon loading of the ink cartridge, interference between the shutter member and the resistant member on the ink cartridge can be avoided. As a result, it becomes possible to provide the ink cartridge in which management of the waste ink can be appropriately performed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the invention, which, however, should not be taken to be limitative to the present invention, but are for explanation and understanding only. 
     In the drawings: 
     FIG. 1 is a perspective view showing external appearance of one embodiment of a label printer according to the present invention; 
     FIG. 2 is an exploded perspective view showing the label printer shown in FIG. 1 in a condition where a case cover is removed; 
     FIG. 3 is a perspective view of the label printer shown in FIG. 1 in a condition where a front cover is opened; 
     FIG. 4 is a section showing a mechanism of a print head station of the label printer of FIG. 1; 
     FIG. 5 is a diagrammatic illustration showing an ink supply system in the label printer; 
     FIG. 6 is a front elevation showing a general construction of the shown embodiment of a tube pump to be employed in the ink supply system; 
     FIG. 7 is a front elevation showing a general constriction of the conventional tube pump to be employed in the ink supply system; 
     FIG. 8 is a front elevation showing a ink storage chamber and an opening and closing mechanism of an atmosphere communication opening of the ink storage chamber; 
     FIG. 9 is a front elevation showing the ink storage chamber shown in FIG. 8 in a condition where the atmosphere communication opening is opened; 
     FIG. 10 is a section showing an internal structure of an ink cartridge; 
     FIG. 11 is a plan view of the ink cartridge shown in FIG. 10; 
     FIG. 12 is a bottom view of the ink cartridge of FIG. 10; 
     FIG. 13 is a conceptual illustration showing a relationship between the ink cartridge shown in FIG.  10  and an ink supply needle unit; 
     FIG. 14 is an enlarged section showing a structure of the ink supply needle unit; 
     FIG. 15 is a section showing an operating condition of the ink supply needle unit of FIG. 14 in an ink supply mode; 
     FIG. 16 is a section in a condition where the ink cartridge is removed; 
     FIG. 17 is a section showing an intermediate position in detaching of the ink cartridge; 
     FIG. 18 is a section showing a condition where the ink cartridge is loaded; 
     FIG. 19 is a section showing a structure of an under case frame in an ink cartridge receptacle chamber; 
     FIG. 20 is an exploded section, in which the ink cartridge and the ink supply needle unit are shown in disassembled position; 
     FIG. 21 is a section showing an intermediate condition in loading or unloading of the ink cartridge and the ink supply needle unit; 
     FIG. 22 is a section showing the ink cartridge and the ink supply needle unit in the loaded condition; 
     FIG. 23 is a front elevation of a head connector before assembling of the printer; 
     FIG. 24 is a front elevation of the head connector corresponding to respective inks after assembling of printer; 
     FIG. 25 is a front elevation of a transfer station; 
     FIG. 26 is a right side elevation of the transfer station shown in FIG. 25; 
     FIG. 27 is a section showing a positional relationship between a head cooling fin and fan; and 
     FIG. 28 is a partial section showing a fin and an ink jet head. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the present invention will be discussed hereinafter in detail with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structures are not shown in detail in order to unnecessary obscure the present invention. 
     It should be noted that while the preferred embodiment will be discussed in terms of a printer employing a paper in a form of roll paper, in which a large number of labels are sequentially arranged on a released paper, as a printing medium, any type of printing medium in a form, a king and a material may be selected adapting the printer. For example, a cut paper may be employed as the printing medium. Also, as a material for the printing medium, film, cloth or any other material may be selected. 
     Also, while the discussion given hereinafter is concentrated for application of the present invention to a label printer, the printer according to the present invention may be applicable for printing mediums, such as perforated continuous paper, name card, card and so forth. In the alternative, the printer according to the present invention can be in a form of a ticket printer and so forth. In short, the present invention is applicable for wide variety of forms of printers. 
     FIG. 1 is a perspective view showing an external appearance of one embodiment of a label printer according to the present invention. 
     The shown embodiment of the label printer employs a roll paper form paper, in which a plurality of labels are sequentially arranged on a released paper. The label printer generally comprises three pars, i.e. a roll paper supply unit  101 , a printing head portion  102  and an ink cartridge receptacle portion  103 . A cover  111  of the roll paper supply unit  101  is provided in detachable fashion. By this, new roll paper  124  can be set (see FIG.  2 ). The roll paper  124  to be stored in the roll paper supply unit  101  is, as discussed later with reference to FIG. 2, fed by a paper feeding mechanism formed between the printing head portion  102  and the ink cartridge receptacle portion  103 . During feeding, printing is performed by a printing head in the printing head portion  102  and ejected out of the apparatus through an ejection opening  114 . It should be appreciated that it is possible to connect a device for peeling off the label from the released paper ejected through the ejection opening  114 . Also, it is possible to connect a device for taking up the label together with the released paper, on which the labels are adhered. 
     The printing head portion  102  is provided for pivoting about the rear end (in the drawing) serving as a pivot shaft with respect to the ink cartridge receptacle portion  103  for opening and closing. By this, it becomes possible to perform maintenance of the printing head of the printing head portion, the paper feeding mechanism and so forth and setting of the roll paper  124 . At the front end portion of the printing head portion  102 , an operating portion  112  including a lamp or liquid crystal indicator for indication of various condition of the label printer, and operating keys, is provided. 
     A front cover  103  of the ink cartridge receptacle portion  103  can be opened and closed about a pivot axis which is established at the left side end in the shown case. By this, upon exchanging of the ink cartridge, the ink cartridge can be unloaded and loaded by opening the front cover  113 . 
     FIG. 2 is a perspective view of the label printer of FIG. 1, showing a condition where the cover  111  of the roll paper supply unit  101  is removed and the printing head portion  102  is pivoted upwardly to be situated in the open position. FIG. 3 is a perspective view of the label printer of FIG. 1, in which the front cover  113  of the ink cartridge receptacle portion  103  is held open. 
     As shown in FIG. 2, a roll  126  on which the roll paper  124  is wound and which is stored in the roll paper supply unit  101 , is mounted on a pair of drive roller  301  (only one is shown). At this condition, the outer periphery of the roll  126  and the drive roller  301  are kept in contact under a pressure due to own weight of the roll paper  124 . At this condition, by rotation of the drive roller  301  and so forth by a driving force of a not shown motor, the outermost roll paper  124  is separated from the remaining inner side roll paper  124  and fed into the label printer. Supply of the roll paper  124  performed in substantially irrespective of feeding by a roll paper feeding mechanism  104  (detail is not shown) located between the printing head portion  102  and the ink cartridge receptacle portion  103 . Accordingly, for adjusting feeding between these two parts, in the supply of the roll paper  124 , supply of the roll paper  124  is controlled to form a loop (not shown in FIG. 2) serving as a buffer. Namely, when a loop is not detected by a loop sensor (not shown) by feeding in the roll paper feeding mechanism  104 , the drive roller  301  is driven to feed the roll paper  124  with forming the loop. 
     A paper guide  131  is provided for sliding in a width direction of the stored roll  126 . Namely, upon storing the roll paper  124 , the paper guide  131  is slide in a magnitude greater than the width of the roll paper  124  to place the roll  126  on the drive roller  301 . Thereafter, the paper guide  131  is slide to the width of the roll  126  to contact a part thereof onto a core member  125  of the roll  126 . By this, upon supplying of the roll paper  124 , vibration of the roll paper  124  in the width direction at the upstream of the drive roller in the supply direction can be restricting by permitting constant fine vibration. It should be noted that, on the paper guide  131 , a stopper  316  for fixing the slide position is provided. 
     In the feeding path of the roll paper  124 , in the vicinity of the feeding path in the roll paper feeding mechanism  104 , an obliquely feeding unit  128  is provided. The obliquely feeding unit  128  includes two obliquely feeding rollers (not shown) contacting with the lower surface of the roll paper  124  and obliquely feeding rolls  129  and  130  contacting with the upper surface of the roll paper  124 . Two obliquely feeding rollers comprises drive roller opposing to the obliquely feeding roll  130  and driven by a driving force from the roll paper feeding mechanism  104 , and driven roller opposing to the obliquely feeding roll  129  and not driven by the driving force. Respective of the driving roller and the driven roller rotate in oblique direction relative to the feeding direction of the roll paper  124  (a rotation axis also lies in oblique with respect to a direction perpendicular to the feeding direction). Also, the obliquely feeding rolls  129  and  130  are mounted in oblique to the feeding direction similarly to the obliquely feeding rollers. By these obliquely feeding rollers and the obliquely feeding rolls  129  and  130 , a transporting force in an oblique direction is applied to the roll paper  124  to be fed to abut the roll paper  124  onto a predetermined guide in the distal side in the drawing. As a result, the roll paper  124  is applied a restricting force in a given direction in the feeding direction and thus can be fed stably without causing vibration in the feeding direction. 
     While it is neglected from illustration in FIG. 2, the roll paper feeding mechanism  104  disposed between the printing head portion  102  and the ink cartridge receptacle portion  103  is constructed with a plurality of belts arranged at the lower side of the roll paper  124  (thereafter arranged on the upper surface of the ink cartridge receptacle portion  103 ), rollers provided at upstream side and downstream side of the belt with respect to the feeding direction for driving the belts, and a wheel  141  (see FIG. 4) arranged at the lower surface of the printing head portion  102  and transmitted the driving force via the predetermined belt among the belts. 
     In FIG. 3, the ink cartridge receptacle portion  103  has four cartridge receptacle chambers  140 Y,  140 M,  140 C and  140 Bk corresponding to four kinds of inks, i.e. yellow (Y), Magenta (M), cyan (C) and black (Bk) inks. In the vicinity of the inlets of respective cartridge receptacle chambers  140 Y,  140 M,  140 C and  140 Bk, shutters  142 Y,  142 M,  142 C and  142 Bk substantially shielding inside of the cartridge receptacle chambers  140 Y,  140 M,  140 C and  140 Bk. The shutters  142 Y,  142 M,  142 C and  142 Bk are pivotably supported at the upper portion so as to avoid erroneous insertion of the user&#39;s hand into the inside of the cartridge receptacle chambers  140 Y,  140 M,  140 C and  140 Bk and erroneous contact to the ink supply needles. Upon insertion of the ink cartridge, insertion of the ink cartridge is performed by orienting the ink cartridge per se toward the distal side to open the shutter. 
     FIG. 4 is a front elevation showing a construction of a printing head station  151  (hereinafter referred to as “PHS”), as primary mechanism of the printing head portion  102 . 
     The PHS  151  has ink-jet heads  155 Y,  155 M,  155 C and  155 Bk having ejection openings arranged beyond overall width of the label in the width direction of the roll paper  124  for performing printing with respect to the label arranged on the roll paper  124 . As these heads  155 Y,  155 M,  155 C and  155 Bk, the ink-jet heads employing so-called bubble-jet system having elements generating thermal energy by generating film boiling of ink as energy utilized for ejection of the ink, are employed. Also, the PHS  151  has an ink collection means for collecting ink ejected through ink ejection openings arranged in respective of the heads  155 Y,  155 M,  155 C and  155 Bk, a blade for sweeping and removing residual ink on an ejection opening forming surface in the vicinity of the ink ejection openings of the heads  155 Y,  155 M,  155 C and  155 Bk, and a recovery system unit  153  having a cap preventing drying in the vicinity of the ink ejection openings. 
     In the PHS  151 , a drive system unit for shifting the head holder unit  152  supporting the heads  155 Y,  155 M,  155 C and  155 Bk in the perpendicular direction from the printing position with respect to the roll paper  124  and shifting the recovery type unit  153  for a given magnitude in horizontal direction along the feeding direction of the roll paper  124 , and a cooling unit for cooling the heads  155 Y,  155 M,  155 C and  155 Bk are provided. 
     On the lower portion of the PHS  151 , wheels  141  are provided at both sides of respective heads  155 Y,  155 M,  155 C and  155 Bk are provided, as set forth above. 
     It should be noted that, while the discussion is given with generally dividing the label printer into three portions as set forth above, it is manner of course that not only the disclosed elements or mechanisms but also other elements and mechanisms are provided in respective portions. Discussion for other elements associated with the disclosed elements, control board, drive, motor, ink supply system and so forth may be arranged appropriately. For the elements and mechanisms other than those disclosed in the foregoing discussion will be constructed with known elements and mechanisms. 
     FIG. 5 is a diagrammatic illustration showing an ink supply system provided in the label printer set forth above. 
     The shown embodiment of the ink supply system has ink storage chambers  203  having ink cartridges  201  and an ink-jet heads  155  for respective colors, a plurality of buffer means  205  and  207 . The ink supply in this system is performed by a pressure difference between tube pumps  209  and  211  and meniscus difference between respective elements. It should be noted that the ink storage chamber  203 , the plurality of buffer means  205  and  207 , tube pumps  209  and  211  and so forth shown in FIG. 5 are provided for each ink similarly to the ink-jet head  155 , the ink cartridge  201 , an ink receptacle  215 . Namely, the ink supply system shown in FIG. 5 is provided for each color of ink. 
     Discussion will be given hereinafter with respect to major ink supply modes in the shown embodiment of the ink supply system. 
     At first, discussion will be given for a mode for maintaining the liquid level of the ink storage chamber  203  at reference liquid level S. L. by supplying ink from the ink cartridge  201  to the ink storage chamber  203 . In this mode, a solenoid  227  is driven to close the atmosphere communication opening  203 A of the ink storage chamber  203  by a plug  225 . On the other hand, by the roller of the tube pump  211 , a tube  241  is crushed for closing. At this condition, the tube pump  209  is driven in counterclockwise direction (C.C.W.) to introduce a vacuum into the buffer tank  205 . At this time, by an one-way valve  219 , ink does not flow into a supply path  237  from the head  155 . On the other hand, ink flows into the buffer tank only from the ink cartridge through the supply path  231 , in which an one-way valve  217  is in forward direction. When an ink level reaches a tube  205 A in the buffer tank  205  by introduction of the ink, the ink flows into the ink storage chamber  203  via the supply passage  233 . By introduction of the ink, when the ink level in the ink storage chamber  203  reaches the reference liquid level S.L., the excessive ink by further flow of the ink flows into the ink cartridge  201  via the supply path  235  to maintain the reference liquid level S.L. 
     Namely, this ink supply mode is performed by driving the tube pump  209  for a given period at an appropriate timing other than the period of printing operation, in which ink is ejected from the head  155 . Thus, a printer control portion can maintain the reference liquid level S.L. in the ink storage chamber  203  only by controlling the drive timing and driving period. The reference liquid level S.L. is held in a range of appropriate meniscus level with respect to the head to appropriately perform ink supply upon ejection of ink. 
     It should be noted that a sensor  223  provided in the ink storage chamber  203  is for detecting presence and absence of the ink and is used for detecting spent out of the ink in the cartridge tank  201  when sensor  223  does not detect presence of the ink even after driving of the tube pump  209  for a given period. 
     Next, discussion will be given for a supply mode upon ejection of ink in the ink-jet head. 
     In this mode, the atmosphere communication opening  203 A of the ink storage chamber  203  is held in open condition, and the tube pump  209  and  211  are held uncrushed, i.e. in through condition. When ejection is performed buy the ink-jet head at this condition, the ink of the ink storage chamber  203  is supplied to the ink-jet head  155  via two systems of supply paths  233 ,  237  and  241 ,  239  due to meniscus difference between the ink storage chamber  203  and the head  155 . 
     The third to be discussed is a supply mode in recirculation of ink to be performed as one of ejection recovery process of the ink-jet head  155 . In this mode, the atmosphere communication opening  203 A of the ink storage chamber  203  is held open and two tube pumps  209  and  211  are driven to rotate in the clockwise direction (C.W. direction). By this, the ink flows into the head  155  via the supply paths  233  and  237  from the ink storage chamber  203 , and in conjunction therewith, the ink flows into the ink storage chamber  203  from the head  155  via the supply paths  239  and  241 . By such recirculation if the ink, the bubble residing within the head  155  can be collected within the ink storage chamber  203  together with the ink and finally discharge to the atmosphere via the atmosphere communication opening  203 A. 
     On the other hand, upon recirculation of the ink as set forth above, the pressure in the head  155  is desired to be maintained at a level slightly higher than the atmospheric pressure. By this, leakage of the ink via the ink ejection opening during recirculation can be minimized. However, in the ink supply system of the shown embodiment, pulsation of the pressure is large since the tube pump  209  is employed as a supply power source and synchronization control between two tube pumps  209  and  211  is not performed, pulsation in the head  155  during recirculation becomes further greater in magnitude. 
     Therefore, in the shown embodiment, by providing the plurality of buffer means  205  and  207  between the head  155  and the tube pumps  209  and  211 , pulsation of the tube pumps  209  and  211  is absorbed by these a plurality of buffer means  205  and  207 . Therefore, during recirculation of the ink, the pressure within the head  155  can be maintained at constant value in the appropriate level. 
     Further ink supply mode is a supply mode during pressurizing recovery to be performed as one of ejection recovery process similarly to the foregoing mode. In this mode, the atmosphere communication opening  203 A is held open and the tube pump  211  is held in the condition where the tube  241  is crushed by the roller. When the tube pump  209  is driven in the clockwise direction (C.W direction) at this condition, the ink is supplied to the head from the ink storage chamber  203  via the supply paths  233  and  237 . The supply pressure at this time is higher than that in recirculation if ink since the tube pump  211  is held inoperative. Therefore, the ink in the head  155  is ejected to the ink receptacle  215  via the ejection opening. Associating with ejection of the ink, high viscous ink within the head  155  can be ejected. 
     The ink within the ink receptacle portion  215  receiving the ejected ink by preparatory ejection performed as one of ejection recovery processes, is introduced into the waste ink storage portion of the ink cartridge  201  via the supply path  243  by a tube pump  213 . 
     FIG. 6 is a front elevation showing a detail of the tube pump  209  ( 211 ) to be employed in the ink supply system of FIG. 5, and FIG. 7 is a similar illustration showing the tube pump in the prior art. 
     As shown in FIG. 6, the shown embodiment of the tube pump  209  is formed with a semicircular recess is a tube holder  212  which forms a support member. Along the semicircular portion, the tube  233  is arranged. At a position offset from the center of the semicircular, a roller rotating portion having a rotary axis is arranged. In the roller rotating portion, depression rollers  209 A,  209 B,  209 C and  209 D are provided (other elements are not necessary to be illustrated). By rotation of the roller rotating portion, respective depression rollers  209 A,  209 B,  209 C and  209 D pushes the tube  233  to place the tube  233  in crushed position in a range of 65 in back and force direction at the lowermost position in the drawing. 
     On the other hand, the tube holder  212  is pushed by means of a spring  216  to be held in the condition illustrated in FIG.  6 . However, while the tube  233  is not depressed and thus in the through condition, it drives the cam  218  to rotate to pivot the tube holder  212  toward left in the drawing about an axis  220 . 
     Here, the difference between the shown embodiment of the tube pump  209  (see FIG. 6) and the conventional tube pump (see FIG. 7) is that, in the conventional tube pump, a tube guide  214  is provided in the overall length for the portion of the tube  233  extending along the semicircular portion. In contrast to this, in the shown embodiment, the guide  210  is provided. only portion except for the semicircular portion. (The guide  210  is also provided symmetrically on the back side relative to the tube, in the drawing.) 
     With the construction of the guide in the shown embodiment, the guide restricts the tube  233  at the portions in the vicinity of the depressing portion other than the portion where the tube is crushed by the depression rollers  209 A to  209 D. In contrast to this, in the prior art shown in FIG. 7, the overall tube  233  including the portion to be depressed is guided. Therefore, when the tube  233  rides over the guide in certain cause, it becomes possible that the tube  233  is cut off by the depression roller. 
     Thus, according to the shown embodiment, since the guide is not present at the portion where the depression rollers  209 A to  209 D act, the possibility of cutting of the tube  233  can be successfully avoided even when large magnitude of offset is caused in the tube  233 . 
     FIGS. 8 and 9 are front elevations showing the detailed configuration of the ink storage chamber  203  shown in FIG.  5  and the opening mechanism of the atmosphere communication opening  203 A. FIG. 8 shows the closed condition of the atmosphere communication opening  203 A and FIG. 9 shows the open condition thereof. 
     The opening mechanism for the atmosphere communication opening  20 A is constructed as follow. A seal lever  247  is pivotably supported by a support shaft  249 . The plug  225  for contacting with the opening end of the atmosphere communication opening  203 A is carried at one end of the seal lever  247 . The other end of the seal lever  247  is connected to a plunger of a solenoid  227  for pivotal movement therewith. Here, the solenoid  227  is so-called latch solenoid which can maintain the plunger in place when no power is supplied and is placed at a given position. On the other hand, the seal lever  247  is connected to a tension spring  255  in the vicinity of the portion where the plug  225  is provided. The other end of the spring  255  is connected to a casing member holding the solenoid  227 . Also, the seal lever  247  is integrally formed with an operation lever  251 . 
     In the opening and closing mechanism as set forth above, as shown in FIG. 5, power supply for the solenoid  227  is controlled depending upon respective ink supply modes to operate the actuating member. In conjunction therewith, by the action of the spring  255 , the seal lever  247  is pivoted. By this, the plug  225  contacts and released from the opening end of the atmosphere communication opening  203 A to open and close the atmosphere communication opening  203 A. 
     In addition to the opening and closing mechanism as set forth above, upon transportation for shipping of the label printer or moving of the installation position of the printer, the operation lever  251  is operated as shown by arrow in FIG. 9 to establish closed position shown in FIG.  8 . By this, even when the label printer subjects vibration during transportation, moving or so forth, ink will never leak through the atmosphere communication opening  203 A. 
     FIG. 10 is a section of the side showing the internal structure of the ink cartridge illustrated in FIG. 5, FIG. 11 is a plan view and FIG. 12 is a bottom view of the ink cartridge. 
     As shown in these drawings, the ink cartridge  201  includes an ink storage chamber  257  and a waste ink storage chamber  260 . At the end of the ink storage chamber, rubber plugs  265  are provided at two portions for passing ink supply needles  275  which will be discussed later. These rubber plugs  265  have a construction sandwiches by the case member of the ink cartridge, an ink absorbing member  263  and a rubber plug holder  267  except for the portions where needles  275 C and  279 C pass through. With this construction, when the ink cartridge is removed from the label printer, the ink adhering on the supply needles  275 C and  279 C drawn out of the ink cartridge can be removed by the ink absorbing member  263 . Therefore, it can prevent contamination of the inside of the label printer by the ink adhering on the supply needles  275 C and  279 C and plugging of the supply nozzles  275 C and  279 C per se. 
     The waste ink storage chamber  260  is formed with a two stages of storage portions communicated at one ends. A portion, in which the ink supply needle  279 C passes through is provided corresponding to the lower stage storage portion. Namely, in the waste storage chamber  260 , the ink supply needle  279 C connected to the supply path  243  as illustrated in FIG. 5 passes through. By this, the waste ink discharged in the ejection recovery process and so forth flows into the lower stage portion of the ink storage chamber  260 . Generally, in the whole body of the ink storage chamber  260  is filled with an ink absorbing member  259 . Thus, the waste ink flowing into the lower stage storage portion of the water storage chamber  260  is absorbed by the ink absorbing member  259 . According to introduction of the waste ink, the region of holding the waste ink among the waste ink gradually extends to the ink absorbing member  259  to partly exude out of the ink absorbing member. On the other hand, adjacent to the end of the waste ink absorbing member  259 , a partitioning wall  261 A is provided. By this, before the waster ink amount exceeds the holding capacity of the ink absorbing member  259 , the exuded ink as set forth above is prevented from moving to the portion at the right side where the ink absorbing member  259  is not filled. Accumulatively, the waste ink among introduced tends to be increased to exceed the holding capacity of the ink absorbing member  259 , Then, the exuded waste ink is then transferred to cause overflow to elevate the liquid lever, When the increased level fills up the wasted in the waste ink storage chamber  260  can be detected. Thus, it becomes possible to promote exchanging of the ink cartridge  201 . 
     The inside of the waste ink storage chamber  260  is adapted to communicate with the outside via a Microtext (tradename: Nitto Denko K.K.) disposed therebetween. By this, leakage of the waste ink can be prevented, and in conjunction therewith, evaporation of the moisture content in the waste ink becomes possible. 
     On the upper surface of the ink cartridge  201 , an identification seal  273  is adhered for identifying the kind of the ink stored therein. Also, at the front end of the ink cartridge  201 , a resistant seal  271  for electrical detection of loading of the ink cartridge  201  and the kind of ink, is adhered. 
     FIG. 13 is an illustration showing a loading condition of the ink cartridge  201  to the label printer. Namely, FIG. 13 shows the condition where respective ink supply needles  275 C pierce the rubber plug  265  of the ink cartridge  201 . 
     The supply needle unit  275  shown in FIG. 13 is connected to the supply path  235  (see FIG. 5) for recirculating the ink from the ink storage chamber  203 . When the ink cartridge  201  is not loaded, the valve  275 A is biased by means of a spring (not shown) toward left in the drawing to block communication between a connection tube  275 D and the needle  275 C. When the ink cartridge  201  is loaded, by an action of a not shown lever upon loading operation of the ink cartridge which will be discussed with reference to FIG.  20  and so forth, the valve  275 A is opened against the spring force to establish communication between the connection tube  275 D and the needle  275 C. 
     A supply needle unit  277  is adapted to be connected to the supply path  231  (see FIG. 5) for supplying ink to the buffer tank  206  (see FIG.  5 ). Irrespective of loading or unloading condition of the ink cartridge  201 , a valve  277 A is normally biased toward left by a spring  277 B to block communication between a connection tube  277 D and the needle  277 C, as shown in FIG.  14 . 
     The supply needle unit  277  establishes the communication between the connection tube  277 D and the needle  277 C in the following condition. As discussed with respect to FIG. 5, when the tube pump  209  is driven in counterclockwise direction in the ink supply mode to the ink storage chamber  203 , vacuum is introduced into the connection tube  277 D via the buffer tank  205 . By this, as shown in FIG. 15, the valve  277 A is shifted toward right against the biasing force of the spring  277 B to establish communication between the connection tube  277 D and the needle  277 C. Then, the ink in the ink cartridge  201  is supplied to the buffer tank  205 . Thus, the supply needle unit  277  serves to perform function of the check valve  217  shown in FIG.  5 . 
     A supply needle unit  279  is connected to the supply path  243  (see FIG. 5) for the waste ink, in which a connection tube  279 D and a needle  279 C are constantly communicated with each other. 
     FIGS. 16 to  18  are illustration showing detailed construction of the shutter  142  of the cartridge receptacle chamber  140  discussed with respect to FIG.  3  and loading operation of the ink cartridge  201  to the cartridge receptacle chamber  140 . 
     As shown in FIGS. 16 to  18 , the shutter  142  is pivoted at a predetermined position on an upper frame  140 U of the cartridge receptacle chamber  140  and slidably engaged with a stopper lever  142 A for sliding movement within a given range. On the other hand, the stopper lever  142 A is similarly pivoted at a point frontwardly shifted from the pivot point of the shutter  142 . The stopper lever  142 A is restricted frontward pivoting range by a stopper  142 C. With the construction set forth above, the shutter  142  is prevented from opening by pulling it frontwardly. 
     Upon insertion of the ink cartridge  201 , as shown in FIG. 17, the ink cartridge  201  is pushed into the ink cartridge receptacle chamber with abutting the front end shoulder thereof with the stopper lever  142 A, By this, the ink cartridge  201  finally abut to a stopper  140 S provided on a lower frame  140 L of the cartridge receptacle chamber  140  and thus is placed at the loading position shown in FIG.  18 . At the loading position, the resistant seal  271  provided on the upper surface of the ink cartridge  201  comes into contact with an electrode  281  at the side of the main body and an electrode  269  for detection of the waste ink also contacts with an electrode  282  at the side of the main body. At this time, since the most part of the tip end portion of the shutter  142  is cut out as shown in FIG. 3, the shutter  142  is prevented from contacting with the resistant seal  271 . 
     FIG. 19 is a diagrammatic longitudinal section showing the entire construction of the lower frame  140 L of the cartridge receptacle chamber  140  set forth above. 
     The lower frame  140 L is formed into tub-shaped configuration to accommodate therein the cartridge receptacle chamber  140  and other ink supply systems shown in FIG.  5 . With such construction, even when leakage of ink is cased in the ink supply system, the ink will not flow out of the lower frame  140 L. Furthermore, the lower frame  140 L is inclined toward the rear side (right side in FIG. 19) and a sensor  283  for detecting the ink accumulated in the lower frame  140 L is provided in the vicinity of the lowermost position of the lower frame. By this, presence of a given amount of leaked ink can be detected. 
     FIGS. 20 to  22  are illustration for explaining positional relationship between the needle  275 C of the supply needle unit  275  and the ink cartridge  201 , in the loading position. 
     At first, immediately before contacting the needle  275 C with the rubber plug  265  of the ink cartridge  201  associating with loading of the ink cartridge  201 , no force is exerted on the lever  275 F. Therefore, the valve  275 A is biased by the spring  275 B to be held in the position blocking communication between the connection tube  275 D and the needle  275 C. 
     Next, as the ink cartridge  201  is further advanced for loading, as shown in FIG. 21, the lever  275 F of the supply needle unit  275  comes into contact with a part of the ink cartridge  201 . At this timing, a portion having the communication opening of the tip end of the needle  275 C already passes through the rubber plug  265  and placed within the ink cartridge  201 . On the other hand, at this time, the lever  275 F has just come into contact with the part of the ink cartridge  201 , the depression force of the ink cartridge  201  is not yet acted on lever  275 F. Accordingly, the communication between the connection tube  275 D and the needle  275 C is still blocked. 
     Next, by further advancement of the ink cartridge  201  in the loading direction, as shown in FIG. 22, the depression force of the ink cartridge  201  acts on the lever  275 F to depress the latter. By this, a connection lever  275 E is shifted toward right in FIG. 22 about one end serving as pivot point. As a result, the connection lever  275 E and the valve  275 A are shifted rightwardly against the biasing force of the spring  275 B to establish communication between the connection tube  275 D and the needle  275 C. 
     As can be clear from the discussion with respect to FIGS. 20 to  22 , the supply needle unit  275  for ink recirculation from the ink storage chamber  203  to the cartridge  201  initially penetrate the tip portion of the needle carrying the communication opening into the ink cartridge  201  and subsequently open the valve  275 A, associating with insertion of the ink cartridge  201  into the cartridge receptacle chamber  140  upon loading. In other words, the relationship of the length of the lever  275 F and the length of the needle  275 C is determined to certainly cause the sequence of actions set forth above. 
     With the construction set forth above, a problem that the valve  275 A is opened before the needle  275 C is inserted into the ink cartridge  201  to cause the ink from the ink storage chamber  203  to leak into the apparatus through the communication opening of the needle  275 C, can be successfully prevented. 
     FIGS. 23 to  26  are illustration showing a head connector  289  and a transfer station  285  provided at a part of the ink supply path and establish connection of the supply tubes. 
     In the shown embodiment, since four kinds of inks, i.e. yellow (Y), magenta (M), cyan (C) and black (Bk), are employed, four ink supply paths are present. Accordingly, it becomes necessary that respective head connectors and the kinds of the inks are corresponded and the head connectors corresponded to the kinds of inks are set corresponding to the transfer station  285 . 
     Therefore, as shown in FIG. 23, the head connector  289  in assembling of printer has respectively four bosses  287 A at both sides. During assembling, the bosses  287 A located at the positions corresponding to respective kinds of inks are cut away to form the head connector  289  after completion of assembling. 
     On the other hand, as shown in the front elevation of FIG.  25  and right side elevation of FIG. 26, the transfer station  285  pairs of bosses  285 A are diagonally arranged. Respective positions of the bosses  285 A corresponds to the positions of the bosses of the head connectors  287  which are cut away for identifying the corresponding kind of the ink. With the construction set forth above, the head connector  289  will never set at erroneous position. Thus, a problem of color mixing can be successfully prevented. 
     FIG. 27 is a section showing a part of the printing head  102  shown in FIG.  1  and so forth. 
     On each ink-jet head  155 , as shown in FIG. 28, a plurality of fins  291  extending in overall length of the head in the longitudinal direction are provided. For generating an air flow along the longitudinal direction of the fines, a fan  293  is provided. The fan  293  is adapted to be driven by a not shown motor. At the front side and rear side of the fan  293 , ducts  295 A and  295 B are provided. The duct  295 A is communicated with the atmosphere via a louver  297  formed in a par of the cover member  114 . By this, relatively low temperature air can be taken from the outside of the printer.