The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
Hereinafter, the preferred embodiments of the present invention will be described in detail on the basis of the accompanying drawings.
Since the embodiments described below are concrete examples of the invention, various limits that are technically preferable are added, but the scope of the invention is not limited thereto unless there is an explicit description for limiting the scope of the invention. In the figures referred to in the following description, the vertical and horizontal scales of a member or a portion may be represented differently from actual scales for the convenience of description.
At first, the configuration of a liquid ejecting apparatus according to an embodiment of the invention will be described with reference to
In
In the carriage 6, ink cartridges 7a to 7d for storing colored inks (inks) of four colors as liquids are loaded, and the colored inks of the colors are supplied to the liquid ejecting head 10. The ejection control for each nozzle of the liquid ejection head 10 is performed in synchronization with the scanning of the carriage 6 and the transport of the paper 2, and an image or the like is formed on the paper 2 with the ink ejected as ink droplets.
The maintenance section 5 includes a cap 11 that seals (capping) openings of nozzles by closely contacting the nozzle forming surface of the liquid ejecting head 10 and a wiper blade 12 that has the shape of a plate made of rubber or the like. The cap 11 is used for a so-called ink suction operation (recovering operation) of sucking ink from the nozzles by driving a communication pump (not shown) along with a function of protecting the nozzles. The wiper blade 12 is used for wiping ink attached to the nozzle forming surface.
Next, the configuration of the liquid ejecting head will be described with reference to
The liquid ejecting head 10 includes a case 30 in which a guiding rib or a recessed portion (partially omitted in drawing) is formed such that the ink cartridges 7a to 7d (See
The ejection section 15 includes nozzles 20 that are formed on one side in a predetermined arrangement, cavities 22 that communicate respectively with the nozzles 20, and reservoirs 23 that supply ink to the cavities 22 for each corresponding ink type. A top cover portion 24 of each cavity 22 is configured so as to be moved by a flexible membrane 25, and ink is ejected from the nozzles 20 by driving piezoelectric sensors 26 that are bonded to the top cover portions 24.
Ink introducing members 40 made of resins are bonded to the top face of the case 30 by using ultrasonic welding so as to be combined with supply sections of the ink cartridges 7a to 7d. Each of the ink introducing members 40 is a member in the shape of a hollow needle having an introduction hole 42 in its apex portion 41 and includes a flange portion 43 having a wide end on the side opposite to the apex portion 41. On the bottom surface of the flange portion 43, a welding protrusion 44 (in a pressed status due to welding in
Each of the ink introducing members 40 includes an introduction flow path 45 therein as a second flow path. The introduction flow path 45 has a flange portion 43 side wider than an apex portion 41 side, and the end of the wider side of the introduction flow path 45 is formed as a communication hole 46.
The case 30 includes a guide section 31 defining the peripheral face of the flange portion 43, a flange attaching face 32 for welding the flange portion 43, and a filter disposing face 33 for disposing the filter 50 in a spot for connecting to the ink introducing member 40. Inside the case 30, a supply path 34 as a first flow path for supplying ink to the ejection section 15 is formed. One end side of the supply flow path 34 is widened to face the filter disposing face 33 to be formed as a communication hole 35.
As a material for the case 30 and the ink introduction member 40, a resin such as PPE (Poly Phenylene Ether) that is appropriate for molding and welding, a mixed material in which a glass material is mixed with a resin, or the like is used.
The filter 50 is a member formed by weaving metal lines to form a mesh and the outer edge portion 50a of the filter is welded to the filter disposing face 33 so as to face the communication hole 46 and the communication hole 35. The filter 50 performs a function of trapping foreign bodies included in the ink that is supplied to the supply flow path 34 from the introduction flow path 45. The reason that the introduction flow path 45 and the supply flow path 34 on the filter 50 side are widened is for reducing the flow resistance (water head loss) of the ink passing though the filter by increasing the effective area of the filter 50.
A spacer member 51 which has an outer diameter approximately the same as that of the filter 50 and has a shape that of a center area Si corresponding to the communication hole 35 and outer regions S2 to S5 thereof are cut away is disposed between the ink introduction member 40 and the filter 50. The spacer member 51 serves to regulate the length between the communication hole 46 forming face 47 and the filter 50 with a high precision. As a result, a recessed portion 52 having a height h and a depth d in a spot corresponding to the areas S2 to S5 of the spacer member 51 is formed in the outer edge portion of the communication hole 46. As shown in the figure, the recessed portion 52 corresponding to the areas S2 to S5 is formed symmetrically with respect to the center of the communication hole 46.
Next, discharge of an air bubble from an introduction flow path will be described with reference to
As shown in
When the suction operation is started, ink 56 and the air bubble 55 which are located inside the introduction flow path 45 move toward the filter 50 due to the pressure difference between the supply flow path 34 and the introduction flow path 45, and, as shown in
As the size of the air bubble 55 decreases, the pressing force of the ink 56 applied to the filter 50 decreases, and the air bubble tries to return to a spherical form away from the filter 50 due to the surface tension applied to the boundary surface between the ink 56 and the air bubble. However, at this moment, the outer edge portion 55a of the air bubble 55 that has been made to enter the recessed portion 52 serves as an anchor, whereby the air bubble 55 remains in a status shown in
When the size of the air bubble 55 decreases so that the air bubble 55 is in a status shown in
As shown in
Referring to
In consideration of performing the locking function (anchor function) realized by making an outer edge portion 55 of the air bubble 55 enter the recessed portion, it is preferable that the recessed portion 52 is designed with an appropriate form and size on the basis of physical properties of the surfaces of ink or the ink introducing member or the like.
While the recessed portion 52 has a function of increasing the air bubble dischargeability by locking the air bubble 55, the recessed portion 52 also has a function of increasing the remaining air bubble amount since the air bubble 55 in the recessed portion 52 cannot be discharged to the end. Accordingly, the recessed portion 52 is not required to be arranged over a wide area, and it is preferable that the disposition position of the recessed portion and the like should be appropriately determined. In this embodiment, by arranging the recessed portion 52 to be symmetrical and symmetrical with respect to the center of the communication hole 46, the air bubble 55 can be locked at multiple points without inclining to one side.
Next, Modified Example 1 will be described with focusing on difference from the above described embodiment, with reference to
A spacer member 51 according to Modified Example 1 is in the shape in which a center region Si corresponding to the communication hole 35 and a region S6 surrounding the outer peripheral of the region S1 are cut out. Accordingly, in Modified Example 1, the recessed portion is continuously formed over the whole outer peripheral portion of the communication hole 46 (See
Next, Modified Example 2 will be described with focusing on difference from the above described embodiment, with reference to
The ink introducing member 40 according to Modified Example 2 has a taper portion 48 formed thin in the outer peripheral portion of the communication hole 46. A recessed portion 52 is formed between the taper portion 48 and the filter 50. As in Modified Example 2, the spacer member is not an essential component to an embodiment of the invention, and the recessed portion may not be a gap having a constant length.
The present invention is not limited to the above described embodiments.
For example, the introducing flow path 45 and the communication hole 46 or the supply flow path 34 and the communication hole 35 may be configured to be eccentric to each other, and profiles of the introducing flow path 45 and the supply flow path 34 are not limited to the above described embodiments.
In addition, the present invention may be applied to a case where a filter is disposed in a supply section of a so-called open-carriage-type liquid ejecting apparatus.
In addition, the configurations in the embodiments of the invention may be combined, omitted, or combined with another configuration that is not shown in the figures appropriately.
Number | Date | Country | Kind |
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2006-143739 | May 2006 | JP | national |