Patent Abstract:
The liquid ejection apparatus is capable of reducing the increase of the viscosity of a liquid due to evaporation of the liquid and also for reducing the quantity of the atmospheric air dissolving into the ink. A liquid seal used for a liquid ejection apparatus which performs recording by ejecting a liquid, at least a part of the liquid seal is formed from a layer compound mixture material including a high molecular compound and an inorganic layer compound. The liquid seal seals the liquid. For example, the liquid seal is an ink cartridge accommodating the liquid therein, or an ink guide member for supplying the ink in the ink cartridge to a recording head unit.

Full Description:
[0001]     The present patent application is a continuation of application Ser. No. 10/921,363 filed Aug. 19, 2004 and claims priority from a Japanese Patent Applications Nos. 2003-296787 filed on Aug. 20, 2003 and 2004-216537 filed on Jul. 23, 2004, the contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a liquid seal and a liquid ejection apparatus. More particularly, the present invention relates to a liquid seal which is used for the liquid ejection apparatus and is capable of maintaining quality of the liquid and also relates to a liquid ejection apparatus employing the liquid seal.  
         [0004]     2. Description of the Related Art  
         [0005]     A liquid ejection apparatus, such as an ink-jet recording apparatus, performs recording on a recording medium, such as a recording paper, by ejecting liquids, such as ink, from a fluid ejection head, such as a recording head. The liquid ejection apparatus includes a liquid accommodating container, such as an ink cartridge, which is detachably mounted with a main body of the liquid ejection apparatus. The liquid accommodating container supplies the liquid therein to a fluid ejection head through a liquid guide member, e.g., a liquid supplying tube as disclosed in Japanese Patent Laid-Open No. 2001-212974.  
         [0006]     If viscosity of the liquid increases due to evaporation of the liquid or if air bubbles is generated in the liquid, performance of the fluid ejection head may deteriorate. In order to prevent a liquid evaporation and the increase of the viscosity, it is necessary to lessen the evaporation through a liquid accommodating chamber, the liquid guide member, and the fluid ejection head. Moreover, in order to prevent generating air bubbles in the liquid, it is necessary to lessen the amount of air being entered into the fluid through the liquid accommodating chamber, the liquid guide member, and the fluid ejection head.  
       SUMMARY OF THE INVENTION  
       [0007]     According to a first aspect of the present invention, there is provided a liquid seal used for a liquid ejection apparatus which performs recording by ejecting a liquid. At least a part of the liquid seal is formed from a layer compound mixture material including a high molecular compound and an inorganic layer compound. The liquid seal seals the liquid. According to the liquid seal, compared with a case if it does not include the inorganic layer compound, the amount of the ink solvent and atmospheric air permeating the liquid seal can be lessened. Therefore, the quality of the liquid is maintainable.  
         [0008]     When the content of the inorganic layer compound in the layer compound mixture material is more than or equal to 1 percent of the weight and less than or equal to 50 percent of the weight, the amount of the ink solvent and atmospheric air permeating the liquid seal can be lessened while the characteristic of the high molecular compound is maintained.  
         [0009]     The liquid seal may be a resin case in which the liquid is accommodated. In this way, the amount of the ink solvent and atmospheric air permeating the liquid accommodating container can be lessened.  
         [0010]     When the liquid ejection apparatus includes: a liquid accommodating container for accommodating the liquid; and a liquid ejection unit for ejecting the liquid, the liquid seal may be a liquid guide member for supplying the liquid from the liquid accommodating container to the liquid ejection unit by allowing communication between the liquid ejection unit and the liquid accommodating container. In this way, the amount of the ink solvent and atmospheric air permeating the liquid guide member can be lessened.  
         [0011]     When the liquid ejection apparatus includes: a liquid accommodating container for accommodating the liquid; a liquid ejection unit for ejecting the liquid; and a liquid guide member for supplying the liquid from the liquid accommodating container to the liquid ejection unit by allowing communication between the liquid ejection unit and the liquid accommodating container, the liquid seal may be a container holding member for detachably holding the liquid accommodating container and for connecting the liquid accommodating container to the liquid guide member by connecting the liquid guide member. In this way, the amount of the ink solvent and atmospheric air permeating the container holding member can be lessened.  
         [0012]     When the liquid ejection apparatus includes: a liquid accommodating container for accommodating the liquid; a liquid ejection unit for ejecting the liquid; and a liquid guide member for supplying the liquid from the liquid accommodating container to the liquid ejection unit by allowing communication between the liquid ejection unit and the liquid accommodating container, and when the liquid ejection unit includes: a head body for ejecting the liquid outside according to a signal input from a body of the liquid ejection apparatus; a base member for holding the head body, where the base member includes a channel unit for guiding the liquid to the head body; and a joint member connecting with each of the liquid guide member and the base member for guiding the liquid supplied from the liquid guide member to the base member, the liquid seal may be the joint member. In this way, the amount of the ink solvent and atmospheric air permeating the joint member can be lessened.  
         [0013]     The liquid seal may include a surface layer which prevents peeling of the inorganic layer compound. Thereby, even if the liquid seal is flexed, the peeling of the inorganic layer compound from the front surface can be prevented. In this case, the surface layer may be unitedly formed by the high molecular compound which does not include the inorganic layer compound. Thereby, the layer including the inorganic layer compound and the surface layer which does not include the inorganic layer compound can be unitedly formed.  
         [0014]     The liquid seal may be formed by extrusion, and the inorganic layer compound may be allotted in the liquid seal along a direction of the extrusion. Thereby, the inorganic layer compound can be densified in a direction perpendicular to the direction of the extrusion, so that the amount of the ink solvent and atmospheric air permeating in the direction perpendicular to the direction of the extrusion can be lessened.  
         [0015]     According to a second aspect of the present invention, there is provided a liquid ejection apparatus which performs recording on a recording medium by ejecting a liquid. The liquid ejection apparatus includes: a liquid accommodating chamber for accommodating the liquid; a liquid ejection unit for ejecting the liquid to the recording medium; a liquid seal for sealing the liquid. The liquid seal is essentially made of layer compound mixture material including a high molecular compound and an inorganic layer compound. According to the second aspect, the same effectiveness as the first aspect can be attained.  
         [0016]     The summary of the invention does not necessarily describe all necessary features of the present invention. The present invention may also be a sub-combination of the features described above. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a perspective view of an ink-jet recording apparatus where a cover is removed.  
         [0018]      FIG. 2  is a perspective view of an ink feed system included in the ink-jet recording apparatus.  
         [0019]      FIG. 3  is an exploded perspective view of the ink cartridge.  
         [0020]      FIG. 4  is a sectional view of the ink sealing film.  
         [0021]      FIG. 5  is a top view of the cartridge holder.  
         [0022]      FIG. 6  is a sectional view of the cartridge holder in the A-A cross section of  FIG. 5 .  
         [0023]      FIG. 7  is a perspective view of the ink guide member.  
         [0024]      FIG. 8  is a sectional view of the cross direction of the ink guide member.  
         [0025]      FIG. 9  is an exploded perspective view of the recording head unit.  
         [0026]      FIG. 10  is a flowchart illustrating a manufacturing process of the bottom case  410 , etc.  
         [0027]      FIG. 11  is an expanded sectional view in which the cross section of the base is expanded to illustrate the outline of the configuration. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]     The invention will now be described based on the preferred embodiments, which do not intend to limit the scope of the present invention, but exemplify the invention. All of the features and the combinations thereof described in the embodiment are not necessarily essential to the invention.  
         [0029]      FIG. 1  is a perspective view illustrating an ink-jet recording apparatus  10  using an embodiment of the present invention where a cover is removed, and  FIG. 2  is a perspective view of an ink feed system included in the ink-jet recording apparatus  10 . As shown in  FIG. 1  and  FIG. 2 , the ink-jet recording apparatus  10  includes: a carriage  42  reciprocally moving along with a main scanning direction above a recording medium  11 , such as a recording paper; a recording head unit  300  mounted with the carriage  42 ; a plurality of ink cartridges  400  accommodating a plurality of colors of ink, respectively; a cartridge holder  200  for detachably fixing the plurality of ink cartridges  400  to the body of the ink-jet recording apparatus  10 ; and a rectangular-shaped ink guide member  100  which connects the recording head unit  300  to the cartridge holder  200 . The ink in the ink cartridges  400  is supplied to the recording head unit  300  through the cartridge holder  200  and the ink guide member  100 . The recording head unit  300  reciprocally moves with the carriage  42  along a guide shaft  48  to perform recording by the ink ejection to the recording medium  11 . The cartridge holder  200  is an example of a container holding member.  
         [0030]     At least a part of each of the ink cartridges  400 , the cartridge holder  200 , the ink guide member  100 , and the recording head unit  300 , i.e., the part being in contact with the ink, is essentially made of layer compound mixture material, which is a mixture of high molecular matter and an inorganic layer compound. For this reason, it is hard to transmit atmospheric air through the ink cartridges  400 , the cartridge holder  200 , the ink guide member  100 , and the recording head unit  300 .  
         [0031]     Although the inorganic layer compound is montmorillonite, which is preferably an example of smectite, it may be another smectite, mica, vermiculite, halloysite, or their synthetic analog. Moreover, although the content of the inorganic layer compound in the layer compound mixture material is preferably more than or equal to 1 percent of the weight and less than or equal to 50 percent of the weigh, it is more preferable that it is more than or equal to 5 percent of the weight and less than or equal to 30 percent of the weight. In this case, the layer compound mixture material can maintain the characteristic of the high molecular matter. Moreover, the ink cartridges  400 , the cartridge holder  200 , the ink guide member  100 , and the recording head unit  300  can be formed by ejection molding.  
         [0032]      FIG. 3  is an exploded perspective view of the ink cartridge  400 . The ink cartridge  400  includes a bottom case  410 , a top case  420 , and an ink sealing film  430 . The bottom case  410  includes recess  412   a  on a surface joined to the top case  420 , and further includes an ink supply port  414  at a surface for supplying the ink outside. The ink sealing film  430  is welded on the perimeter of the recess  412   a  to form an ink accommodating chamber  412  which accommodates the ink in the lower case  410 . The top case  420  is connected to the bottom case  410  to form a resin case of the ink cartridge  400 . The bottom case  410  and the top case  420  are essentially made of the layer compound mixture material. When forming the bottom case  410  and the top case  420 , the layer compound mixture material includes polypropylene as the high molecular matter.  
         [0033]      FIG. 4  is a sectional view of the ink sealing film  430 . The ink sealing film  430  includes a welding film  432 , a mixture film  434 , and a heat-resistant film  436  in this order from a side to be welded to the bottom case  410 . The welding film  432  includes material similar to the bottom case  410 , and welded to the bottom case  410 . When the bottom case  410  includes polypropylene, the welding film  432  is formed with cast polypropylene. The mixture film  434  is essentially made of the layer compound mixture material, and prevents the ink solvent and the atmospheric air permeating the ink sealing film  430 . When forming the mixture film  434 , the layer compound mixture material includes polypropylene as the high molecular matter. The heat-resistant film  436  is essentially made of material of which a softening point higher than the welding film  432 , and when welding the welding film  432 , it maintains shape of the ink sealing film  430 .  
         [0034]      FIG. 5  is a top view of the cartridge holder  200 , and  FIG. 6  is a sectional view of the cartridge holder  200  in the A-A cross section of  FIG. 5 . As shown in  FIG. 6 , the cartridge holder  200  includes a plate-like member  202  and a sealing film  204  welded to a surface of the plate-like member  202 . As shown in  FIG. 5 , the plate-like member  202  has a substantially rectangular shape, and includes a plurality of cylindrical cartridge connection units  210  to which the ink supply ports  414  of ink cartridges  400  are connected, a plurality of conveying member communicating pores  220  to which the ink guide member  100  is connected, and a plurality of slot units  230  which connect the plurality of cartridge connection units  210  to the conveying member communicating pores  220 , respectively. The slot units  230  are formed over the surface of the plate-like member  202 , and form the channels for the liquid by sealed by the sealing film  204 . The plate-like member  202  is essentially made of the layer compound mixture material. When forming the plate-like member  202 , the layer compound mixture material includes polypropylene as the high molecular matter. In addition, although the sealing film  204  is formed by inserting the mixture film between the welding film and the heat-resistant film like the ink sealing film  430  shown in  FIG. 4  in the present embodiment, the configuration is not limited to it.  
         [0035]      FIG. 7  is a perspective view of the ink guide member  100 . The ink guide member  100  has a rectangular shape, and includes a plurality of cylindrical holder side connection units  102  at one end. The holder side connection units  102  are inserted to the conveying member communicating pores  220  of the cartridge holder  200 . The ink guide member  100  further includes a plurality of cylindrical head side connection units  104  at the other end. The head side connection units  104  are connected to the recording head unit  300 . The holder side connection units  102  and the head side connection units  104  are formed with the base  110  (to be described hereinafter) of the ink guide member  100  shown in  FIG. 8  by two colors.  
         [0036]      FIG. 8  is a sectional view of the cross direction of the ink guide member  100 . The ink guide member  100  includes a base  110  and the ink sealing film  120 . The base  110  is essentially made of the layer compound mixture material, and includes a plurality of slot units  112   a , which extend along the longitudinal direction and are spaced apart from each other. The ink sealing film  120  is welded to whole surface of the base  110 , and openings of the plurality of slot units  112   a  are sealed to form a plurality of channel units  112 . As shown in  FIG. 1 , the ink guide member  100  connects the recording head unit  300  to the cartridge holder  200 . The recording head unit  300  moves with the carriage  42 . For this reason, the ink guide member  100  needs to have flexibility. When forming the base  110  of the ink guide member  100 , the layer compound mixture material includes thermoplastic elastomer, for example, SEPS (polystyrene-polyethylene-polypropylene-polystyrene) polymer as the high molecular matter. In addition, although the ink sealing film  120  is formed by inserting the mixture film between the welding film and the heat-resistant film like the ink sealing film  430  shown in  FIG. 3  and  FIG. 4  in the present embodiment, the configuration is not limited to it.  
         [0037]      FIG. 11  is an expanded sectional view in which the cross section of the base  110  is expanded to illustrate the outline of its configuration.  FIG. 11  illustrates the base  110  being cut in the thickness direction along the longitudinal direction of the base  110 . For purposes of description, scale of the inorganic layer compounds  142  is magnified in the Figure.  
         [0038]     The base  110  shown in  FIG. 11  includes an central layer  132  including a inorganic layer compound  142  and a high molecular compound  140 , and the surface layers  130  and  134  arranged on surfaces of the central layer  132 . The central layer  132  and the surface layers  130  and  143  are formed by extruding the layer compound mixture material, which is a mixture of the inorganic layer compound  142  and the high molecular compound  140 , towards a predetermined direction. In  FIG. 11 , the direction of the extrusion is right (or left) direction. By the force of the extrusion, the inorganic layer compound  142  is aligned along the direction of the extrusion of the central layer  132 . Thereby, the inorganic layer compound  142  can be densified in a direction perpendicular to the direction of the extrusion. Therefore, in the base  110 , the amount of the ink solvent and atmospheric air passing in the direction perpendicular to the direction of the extrusion (the vertical direction in  FIG. 11 ) can be lessened.  
         [0039]     At the time of the extrusion molding, the high molecular compound  140  in the surfaces being in contact with open air is cured faster than a central area. In this case, since the high molecular compound  140  is cured from the front surfaces towards the center pushing the inorganic layer compound  142  to the central area, the surface layers  130  and  134  are essentially made of the high molecular compound  140  which do not include the inorganic layer compound  142 . Therefore, the surface layers  130  and  134  which do not include the inorganic layer compound  142  and the central layer  132  which includes the inorganic layer compound  142  can be formed unitedly and easily. Moreover, since the central layer  132  and the surface layers  130  and  134  are unitedly formed including the same high molecular compound  140 , peeling between these layers can be prevented.  
         [0040]     The above-mentioned surface layers  130  and  134  prevent peeling of the inorganic layer compounds  142  provided in the central layer  132 . Thereby, even if the base  110  is flexed, the peeling of the inorganic layer compound  142  on its front surfaces can be prevented. Moreover, since the inorganic layer compound  142  does not appear on the front surfaces of the base  110 , the inorganic layer compound  142  can be prevented from hooking other components on the front surfaces of the base  110 .  
         [0041]      FIG. 9  is an exploded perspective view of the recording head unit  300 . The recording head unit  300  includes a joint member  302 , a base member  304 , and a head body  306 . The head body  306  ejects the ink onto the recording medium  11  shown in  FIG. 2  according to the signal input from the body of the ink-jet recording apparatus  10 . The base member  304  holds the head body  306 , and supplies ink to the head body  306 .  
         [0042]     The joint member  302  includes a sealing film  320 , which is welded to the whole surface of the connection base  310 , and the connection base  310 . The connection base  310  has a plurality of conveying member connection unit  312 , head side connection units  314 , and a plurality of channel grooves  316 . The conveying member connection unit  312  is exposed from film ports  322  formed in the sealing film  320 , and receives a plurality of kinds of ink respectively by inserting the head side connection units  104  of the ink guide member  100 . Sealing of the head side connection units  314  is accomplished by the sealing film  320 , and it is connected to the base member  304  and supplies the plurality of kinds of ink to the base member  304 , respectively. The channel grooves  316  guides the plurality of kinds of ink received by the conveying member connection units  312  to the head side connection units  314 , respectively. The connection base  310  is essentially formed of the layer compound mixture material. When forming the connection base  310 , the layer compound mixture material includes the polyphenylene ether resin as the high molecular matter. The composition of the sealing film  320  is similar to the ink sealing film  430  shown in  FIGS. 3 and 4  except for the composition of the welding film  432 . In the sealing film  320 , a layer corresponding to the welding film  432  is essentially made of the material similar to polyphenylene ether resin. However, it should be noted that the sealing films  320  is not limited to it.  
         [0043]      FIG. 10  is a flowchart illustrating a manufacturing process of the bottom case  410  and the top case  420  of the ink cartridge  400 , the plate-like member  202  of the cartridge holder  200 , and the base  110  of the ink guide member  100 . First, the pellet of the layer compound mixture material, which is the mixture of the inorganic layer compound and the high molecular matter, is prepared (S 10 ). Then, the pellet is melted (S 20 ), and placed into a die. Then, the bottom case  410 , the top case  420 , the plate-like member  202 , and the base  110  are ejection molded (S 30 ). In this way, the bottom case  410 , the top case  420 , the plate-like member  202 , the base  110 , and the connection base  310  can be formed by ejection molding.  
         [0044]     As mentioned above, as for the ink-jet recording apparatus  10 , since the bottom case  410  and the top case  420  of the ink cartridge  400 , the plate-like member  202  of the cartridge holder  200 , and the base  110  of the ink guide member  100  are essentially made of the layer compound mixture material, which is the mixture of the inorganic layer compound (e.g., montmorillonite) and the high molecular matter, it is hard for the atmospheric air to dissolve into the ink. For this reason, gas ejection from the recording head unit  300  instead of the ink, or so called “dot defect”, is reduced, and even if it performs continuation recording, recording quality does not deteriorate so easily. Moreover, frequency of ink ejection for the restoration from the dot defect, i.e., frequency of cleaning, is reduced. Therefore, the quantity of the ink that is used for the recording purpose can be increased. Moreover, since the ink solvent cannot evaporate easily until the ink reaches the recording head unit  300 , the viscosity of the ink does not increase so easily.  
         [0045]     Moreover, as for the member conventionally formed by the ejection molding, it can be manufactured by the same process as the former method except that the process of making the layer compound mixture material is added. Therefore, the increase in manufacturing cost is avoidable.  
         [0046]     In addition, the ink-jet recording apparatus  10  is an example of a liquid ejection apparatus. Moreover, the ink cartridge  400  is an example of an ink accommodating container, and the recording head unit  300  is an example of a liquid ejection unit. However, the liquid ejection apparatus is not limited to it. Other examples of a liquid ejection apparatus are a color filter manufacturing apparatus for manufacturing a color filter of a liquid crystal display. In this case, the cartridge accommodating coloring material is an example of a liquid accommodating container. Yet another example of the liquid ejection apparatus is an electrode forming apparatus for forming electrodes of an organic EL display, an FED (field luminescence display), and the like. In this case, a cartridge accommodating electrode material (conduction paste) of the electrode forming apparatus is an example of the liquid accommodating container. Yet another example of the liquid ejection apparatus is a biochip manufacturing apparatus for manufacturing a biochip. In this case, the cartridge of the biochip manufacturing apparatus accommodating organic substance and a sample is an example of the liquid accommodating container. The liquid ejection apparatus of the present invention further includes another liquid ejection apparatus having an industrial application. The recording medium is an object onto which the recording is performed by ejecting the liquid, and includes a circuit board on which circuit patterns such as display electrodes are formed, a CD-ROM on which a label is printed, and a prepared slide on which a DNA circuit is recorded, as well as the recording paper.  
         [0047]     Although the present invention has been described by way of exemplary embodiments, it should be understood that those skilled in the art might make many changes and substitutions without departing from the spirit and the scope of the present invention which is defined only by the appended claims.

Technology Classification (CPC): 1