JP2006076111A - Inkjet head and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head wherein foreign matter created in a process of manufacturing the inkjet head is surely removed in a condition that a filter in the inkjet head and an ink supply means from the ink cartridge are attached thereto. <P>SOLUTION: This inkjet head is constituted of a fluid channel plate 1 having a common liquid chamber 1c with a filter 7 and a plurality of pressurizing liquid chambers 1e, a nozzle plate 2 having nozzles 2a respectively corresponding to the pressurizing liquid chambers 1e to be bonded to the fluid channel plate 1, and drive elements formed corresponding to the pressurizing liquid chambers 1e. The fluid channel plate 1 is equipped with liquid discharge holes 8, 8 each having the sufficiently small fluid resistance. A cleaning liquid is allowed to flow from the side of the pressurizing liquid chamber 1e and the upstream side of the filter 7 before the nozzle plate 2 is bonded to the fluid channel plate 1, and then foreign matter 10 entering the inkjet head in the process of manufacturing is surely removed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet head and an ink jet recording apparatus. More specifically, the present invention reliably removes foreign matter in the ink jet head generated during the manufacturing process of the ink jet head in a state where an ink supply means from a filter and an ink cartridge is mounted. The present invention relates to an ink jet head and an ink jet recording apparatus using the ink jet head.

In general, an ink jet head includes a nozzle formed with a size of several tens of μm and an ink liquid chamber. Conventionally, foreign matters mixed in the manufacturing process of the ink jet head have been caused to flow into the ink jet head by ink and clog the nozzles, causing defective ejection of the ink jet head.
In recent years, output devices have been speeded up due to improvements in processing capabilities of PCs. In the case of an ink jet head, an increase in the number of nozzles is required to cope with the increase in speed, and accordingly, it is necessary to improve foreign matter removing means that causes ejection failure.

In an ink jet recording apparatus, in order to prevent the nozzles of the ink jet head from being blocked by foreign matter or the like, it is necessary to install a filter for removing foreign matters and bubbles in the ink supply system that supplies ink from the ink cartridge to the nozzles. ing.
However, it is difficult to remove foreign matter with the filter attached. Therefore, it is necessary to attach a filter after removing the foreign matter in the inkjet head.

The following techniques are known as techniques relating to the removal or cleaning of foreign matters in an ink jet head related to the present invention.
That is, the “inkjet recording apparatus” disclosed in Patent Document 1 is an example of cleaning a filter alone, and the “inkjet head cleaning method” disclosed in Patent Document 2 is to clean an inkjet head using ultrasonic cleaning. The “inkjet recording apparatus” disclosed in Patent Document 3 is an example in which the filter is removed from the inkjet head, and the “inkjet head” disclosed in Patent Document 4 has a complicated flow path shape and a foreign object. This is an example of preventing the nozzle from reaching the nozzle.
In addition, the “inkjet head cleaning method and apparatus” disclosed in Patent Literature 5 and the “inkjet recording head and inkjet recording head manufacturing method” disclosed in Patent Literature 6 are both provided in the inkjet common liquid chamber. This is an example in which a liquid discharge port is provided.
Japanese Patent Application No. 7-314705 Japanese Patent No. 3179332 Japanese Patent Application No. 11-34350 JP 2001-328264 A Japanese Patent No. 3108788 JP 2000-238270 A

  As described above, the conventional inkjet head cleaning method includes a method of cleaning the filter alone (Patent Document 1), a method of ultrasonically cleaning the inkjet head unit (Patent Document 2), and a method of removing the filter and cleaning (Patent Document 1). Reference 3), an example of complicating the flow path shape and preventing foreign matter from reaching the nozzle is known (Patent Document 4). However, in each method, dust is generated when the filter unit is mounted. There is a captive that will end up. Moreover, it is necessary to clean the filter unit independently, which increases the cost. Therefore, in the inkjet heads disclosed in Patent Documents 5 and 6, the inkjet head is cleaned with the filter unit attached by providing a cleaning liquid discharge port in the common ink chamber, but there is a plug that plugs the cleaning liquid discharge port. It is necessary separately.

  In the present invention, even if the number of nozzles increases corresponding to the increase in the speed of the output device, the filter and the foreign matter in the inkjet head generated during the manufacturing process of the inkjet head are mounted with the ink supply means from the filter and the ink cartridge. It is an object of the present invention to provide an ink jet head that is surely removed in a state where it has been removed to eliminate the possibility of contamination.

  According to the first and second aspects of the present invention, it is possible to reliably remove the foreign matter in the ink jet head by providing the liquid discharge port in the ink jet head, and it is accurate without causing a discharge failure due to the foreign matter generated in the manufacturing process. An object of the present invention is to provide a high-quality ink jet head capable of discharging ink.

  The invention of claim 3 aims to surely remove foreign matter by another liquid discharge port even when a part of the liquid discharge port is blocked by the foreign matter when removing the foreign matter in the ink jet head. .

  An object of the invention of claim 4 is to remove foreign matters without obstructing the flow of fluid by making the opening area of the liquid discharge port larger than the opening area of the total number of nozzles.

  The object of the present invention is to close the liquid discharge port with a nozzle plate without using an excessive sealing member.

  The object of the present invention is to remove the cleaning liquid for removing the foreign matter in the ink jet head and the foreign matter in the ink, and reliably remove the foreign matter on the downstream side of the filter provided in the ink jet head from the liquid discharge port.

  The invention of claim 7 provides an ink jet recording apparatus capable of performing high-quality printing without causing ejection failure by forming an ink jet recording apparatus using the ink jet head of the inventions of claims 1 to 6. The purpose is to do.

  The invention of claim 1 is a flow path plate having a common liquid chamber and a plurality of pressurized liquid chambers, a nozzle plate having discharge holes corresponding to the plurality of pressurized liquid chambers, and joined to the flow path plate, An ink jet head comprising a driving element formed corresponding to the pressurized liquid chamber is characterized in that the flow path plate is provided with a liquid discharge port having a sufficiently small fluid resistance as compared with the discharge hole.

  According to a second aspect of the present invention, in the ink jet head according to the first aspect, the fluid resistance of the liquid discharge port is about 1/10 of the fluid resistance of the one discharge hole.

  A third aspect of the present invention is the inkjet head according to the first or second aspect, wherein a plurality of the liquid discharge ports are formed in the flow path plate.

  According to a fourth aspect of the present invention, in the ink jet head according to any one of the first to third aspects, an opening area of the liquid discharge port is larger than a total opening area of the plurality of ejection holes.

  According to a fifth aspect of the present invention, in the ink jet head according to any one of the first to fourth aspects, the liquid discharge port is closed when the nozzle plate is joined to the flow path plate.

  According to a sixth aspect of the present invention, in the ink jet head according to any one of the first to fifth aspects, a filter is provided to prevent entry of foreign matter upstream of the pressurized liquid chamber of the flow path plate. To do.

  A seventh aspect of the invention is an ink jet recording apparatus that records an image on a recording medium by ejecting ink droplets from the ejection holes with energy generated by an actuator driven in accordance with a recording signal. And an ink storage member for supplying ink to the inkjet head.

  Since the ink jet head according to claims 1 and 2 is provided with a liquid discharge port whose fluid resistance is sufficiently smaller than that of the discharge hole, foreign matter generated in the manufacturing process of the ink jet head can be surely prevented without obstructing the flow of the liquid. Can be removed.

  In the ink jet head according to claim 3, by providing a plurality of liquid discharge ports, it becomes possible to efficiently remove foreign matters, and even if some liquid discharge ports are blocked by foreign matters, other liquid discharge ports Foreign matter can be removed more reliably.

  In the ink jet head according to the fourth aspect, since the opening area of the liquid discharge port is larger than the opening area of the total number of nozzles, foreign matters mixed in the ink jet head can be cleaned without obstructing the flow of the cleaning liquid.

  In the ink jet head according to the fifth aspect, the liquid discharge port is closed by joining the nozzle plates. Therefore, the liquid discharge port can be closed without adding an extra sealing member such as a blocking plug.

  The ink jet head according to claim 6 is provided with a filter on the upstream side of the liquid discharge port, and therefore, when a filter unit for removing foreign matter is mounted, there is no possibility of dust generation and foreign matter is removed. Can do.

  In the ink jet recording apparatus according to the seventh aspect, since the ink-jet head having good cleaning properties described in the first to sixth aspects is mounted, it is possible to improve the print quality without causing a discharge failure.

According to the present invention, even in an ink jet head having a large number of nozzles corresponding to the increase in the speed of the output device, foreign matters generated in the manufacturing process are mounted in a state where a filter in the ink jet head and an ink supply means from an ink cartridge are mounted. The purpose is to surely remove and eliminate the possibility of shipping an ink jet head mixed with foreign matter, and the configuration includes a flow path plate having a common liquid chamber and a plurality of pressurized liquid chambers, In an inkjet head comprising a nozzle plate having a discharge hole corresponding to the pressurized liquid chamber and joined to the flow path plate, and a drive element formed corresponding to the pressurized liquid chamber, It has a liquid discharge port with a sufficiently low fluid resistance compared to the discharge hole, and it is simultaneously washed from the ink supply side and the pressurized liquid chamber side before joining the nozzle plate to the flow path plate. By flowing fluid, but which is adapted to reliably remove foreign matter that has entered the manufacturing process of the ink jet head.
Embodiments of the present invention will be described below with reference to FIGS.

1 is a cross-sectional view showing an ink jet head according to a first embodiment to which the present invention is applied, and FIG. 2 is an exploded perspective view showing the ink jet head shown in FIG.
The ink jet head of Example 1 includes a flow path plate 1 made of a silicon substrate or the like on which a plurality of through holes 1a and individual liquid chambers 1b serving as ink flow paths are formed, and an Ni electroforming on the upper surface of the flow path plate 1. The nozzle plate 2 having a plurality of nozzles (ejection holes) 2a formed thereon is joined, and the vibration plate 3 having an ink supply port 3a formed on the lower surface of the flow path plate 1 and formed by Ni electroforming or the like is joined. The path plate 1 and the diaphragm 3 constitute a liquid chamber portion of the ink jet head. Each individual liquid chamber 1b includes a common liquid chamber 1c, a fluid resistance portion 1d, and a pressurized liquid chamber 1e, and communicates with the nozzle 2a through a communication hole.

  A base member 4 made of metal is provided below the diaphragm 3, and an actuator unit composed of two rows of stacked piezoelectric elements 5 provided on the base member 4 is joined to the lower surface of the diaphragm 3. . A frame member 6 having a common ink flow path 6 a is provided outside the piezoelectric element 5, the diaphragm 3 is joined to the frame member 6, and the common ink flow path 6 a and the common liquid chamber 1 c of the flow path plate 1 are connected. The ink is communicated via the ink supply port 3a to supply ink to each individual liquid chamber 1b.

  In the ink jet head having such a configuration, when a driving voltage is applied to the piezoelectric element 5 according to a recording signal, the piezoelectric element 5 is displaced in the stacking direction (vertical direction in FIG. 1), and the diaphragm 3 is individually separated. The liquid chamber is deformed and displaced to reduce the volume of the liquid chamber, the pressure in the liquid chamber is increased, and ink droplets are ejected from the nozzles 2a of the nozzle plate 2 through the communication holes.

FIG. 3 is a cross-sectional view schematically showing the individual liquid chambers of the flow path plate of the inkjet head. For convenience of explanation, FIG. 3 shows an edge shooter type inkjet head, unlike the side shooter type shown in FIGS.
As shown in FIG. 3, each individual liquid chamber 1b of the flow path plate 1 in which a plurality of individual liquid chambers 1b are formed includes a common liquid chamber 1c, a fluid resistance portion 1d, and a pressurized liquid chamber 1e. A filter 7 is provided at 1c. Further, liquid discharge ports 8 and 8 are formed on the outer sides adjacent to the pressurized liquid chambers 1e at both ends of the pressurized liquid chambers 1e connected in a row in the flow path plate 1.

  When the nozzle plate 2 formed with a plurality of nozzles 2a corresponding to the individual liquid chambers of the flow path plate 1 is joined to the flow path plate 1 with an adhesive or the like, each pressurized liquid chamber 1e of the flow path plate 1 is Although communicating with the atmosphere via the nozzle 2 a, the liquid discharge ports 8, 8 located at both ends are closed by the nozzle plate 2.

  In the edge shooter type ink jet head shown in FIG. 3, ink is supplied from the common ink flow path 6 a formed in the frame member 6 to the common liquid chamber 1 c of the flow path plate 1 through the ink supply port 3 a of the vibration plate 3. When a drive voltage corresponding to the recording signal is applied to the piezoelectric element 5, the piezoelectric element 5 is displaced, and when the diaphragm 3 is deformed and displaced to the piezoelectric element side, the volume of the liquid chamber is increased. When the diaphragm 3 is deformed and displaced to the individual liquid chamber side through the resistance portion 1d and then the volume of the pressurized liquid chamber 1e decreases, the internal pressure of the pressurized liquid chamber 1e decreases. Rises and ink droplets are ejected from the nozzles 2 a of the nozzle plate 2. At this time, since the liquid discharge ports 8 and 8 are covered with the nozzle plate 2, the ink does not flow out. In addition, if the fluid resistance portion 1d communicating with each nozzle 2a is clogged with foreign matter larger than the opening area of the fluid resistance portion, a problem occurs during ink ejection.

FIG. 4 is a cross-sectional view schematically showing a first removal method for removing foreign matters generated during the manufacturing process of the inkjet head.
The first removal method is performed before the nozzle plate 2 is joined to the flow path plate 1 during the manufacturing process of the inkjet head, and the pressurized liquid chambers 1e, In addition, the foreign matter 10 existing downstream of the filter 7 can be removed from the pressurized liquid chamber 1e and the liquid discharge ports 8 and 8 by simultaneously flowing from the liquid discharge ports 8 and 8. The first removal method is effective when the foreign matter 10 is present in the pressurized liquid chamber 1e or in the common liquid chamber 1c downstream of the filter 7.

FIG. 5 is a cross-sectional view schematically showing an example in which foreign matter cannot be removed in the first removal method.
When the foreign material 10 is caught by the fluid resistance portion 1d, or when the foreign material 10 is caught by the fluid resistance portion 1d during the first removal method, the first removal method removes the foreign material 10. Can not do it. In such a case, the foreign material 10 can be removed by performing the second removal method.

FIG. 6 is a cross-sectional view schematically showing a second removal method for removing foreign matter generated during the manufacturing process of the inkjet head.
The second removal method is performed before the nozzle plate 2 is joined to the flow path plate 1 during the manufacturing process of the ink jet head, and the cleaning liquid from the upstream side of the filter 7 passes through the common liquid chamber 1c as indicated by an arrow. At the same time as flowing out from the liquid discharge ports 8, 8 and flowing out from the respective liquid discharge ports 8, 8 from each pressurized liquid chamber 1 e through the fluid resistance portion 1 d and the common liquid chamber 1 c, they exist downstream of the filter 7. The foreign matter 10 can be removed from the liquid discharge ports 8 and 8. Further, as shown in FIG. 5, it is possible to remove the foreign substance 10 captured by the fluid resistance portion 1d. At this time, the large foreign matter 10 in the pressurized liquid chamber 1e that cannot pass through the fluid resistance portion 1d is removed by stopping the supply of the cleaning liquid from the nozzle plate 2 side and flowing the cleaning liquid only from the ink supply port side. be able to.

  By carrying out the first and second removal methods, foreign substances present in the inkjet head can be removed without being disturbed by the filter. Further, even if dust is generated when the ink supply unit is mounted, which has been a problem in the past, the filter 7 is mounted, so that there is no possibility that foreign matter is mixed into the inkjet head.

  After the foreign matter in the ink jet head is removed, the nozzle plate 2 is joined to the flow path plate 1 to complete the ink jet head as shown in FIG. 3 in which the foreign matter generated in the manufacturing process is completely eliminated. By simply closing the liquid discharge port 8 with the nozzle plate 2 using an adhesive or the like, no special sealant is required, and the liquid discharge ports 8 and 8 can be closed simultaneously with the joining of the nozzle plate 2.

FIG. 7 is a cross-sectional view showing the main configuration of the ink jet recording apparatus according to the second embodiment to which the present invention is applied, and FIG. 8 is a side cross-sectional view of the ink jet recording apparatus shown in FIG.
The ink jet recording apparatus according to the second embodiment supplies the ink to the recording head 34, which includes the carriage 33 movable in the main scanning direction inside the recording apparatus main body 21, the ink jet head according to the first embodiment mounted on the carriage 33, and the recording head 34. A paper feed cassette (or a paper feed tray) that accommodates a print mechanism 22 including an ink cartridge 35 and the like, and can stack a large number of sheets 23 from the front side in the lower part of the apparatus main body 21 may be used. ) 24 can be removably mounted, and the manual tray 25 for manually feeding the paper 23 can be opened, and the paper 23 fed from the paper feed cassette 24 or the manual tray 25 can be opened. After a required image is recorded by the printing mechanism unit 22, the paper is discharged onto a paper discharge tray 26 mounted on the rear side.

  The printing mechanism unit 22 holds the carriage 33 slidably in the main scanning direction (the vertical direction in FIG. 8) with a main guide rod 31 and a sub guide rod 32 which are guide members horizontally mounted on left and right side plates (not shown). In this carriage 33, a plurality of ink ejection openings are main-scanned by a recording head 34 composed of an inkjet head that ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink droplets are arranged in a direction crossing the direction and the ink droplet ejection direction is directed downward. In addition, each ink cartridge 35 for supplying ink of each color to the recording head 34 is replaceably mounted on the carriage 33.

  The ink cartridge 35 has an atmosphere port communicating with the atmosphere above, a supply port for supplying ink to the recording head 34 below, and a porous body filled with ink inside, and a porous capillary tube. The ink supplied to the inkjet head is maintained at a slight negative pressure by force.

  Further, although the recording heads 34 of the respective colors are used here as the recording heads, one recording head having nozzles for ejecting ink droplets of the respective colors may be used. Further, the ink jet head used as the recording head 34 is a piezo type that pressurizes ink through a vibration plate that forms a liquid chamber wall surface with an electromechanical conversion element such as a piezoelectric element like the ink jet head of Example 1, or a heating resistor. Bubble type that pressurizes ink by generating air bubbles by the body, or electrostatic type that pressurizes ink by displacing the diaphragm with an electrostatic force between the diaphragm that forms the wall surface of the ink flow path and the electrode facing it In this embodiment, a piezo ink jet head is used.

  Here, the carriage 33 is slidably fitted to the main guide rod 31 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 32 on the front side (downstream side in the paper conveyance direction). is doing. In order to move and scan the carriage 33 in the main scanning direction, a timing belt 40 is stretched between a driving pulley 38 and a driven pulley 39 that are rotationally driven by a main scanning motor 37, and the timing belt 40 is moved to the carriage 33. The carriage 33 is driven to reciprocate by forward and reverse rotation of the main scanning motor 37.

  On the other hand, in order to convey the sheet 23 set in the sheet feeding cassette 24 to the lower side of the head 34, the sheet feeding roller 41 and the friction pad 42 for separating and feeding the sheet 23 from the sheet feeding cassette 24 and the sheet 23 are guided. A guide member 43, a transport roller 44 that reverses and transports the fed paper 23, a transport roller 45 that is pressed against the peripheral surface of the transport roller 44, and a tip that defines the feed angle of the paper 23 from the transport roller 44 A roller 46 is provided. The transport roller 44 is rotationally driven by a sub-scanning motor 47 through a gear train.

  A printing receiving member 49 is provided as a paper guide member for guiding the paper 23 fed from the transport roller 44 below the recording head 34 corresponding to the range of movement of the carriage 33 in the main scanning direction. A conveyance roller 51 and a spur 52 that are rotationally driven to send the paper 23 in the paper discharge direction are provided on the downstream side of the printing receiving member 49 in the paper conveyance direction, and the paper 23 is further delivered to the paper discharge tray 26. A roller 53 and a spur 54, and guide members 55 and 56 that form a paper discharge path are disposed.

  At the time of recording, the recording head 34 is driven according to the image signal while moving the carriage 33, thereby ejecting ink onto the stopped paper 23 to record one line. Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 23 reaches the recording area, the recording operation is terminated and the paper 23 is discharged.

  A recovery device 57 for recovering the ejection failure of the head 14 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 33. The recovery device 57 has a cap unit, a suction unit, and a cleaning unit. The carriage 33 is moved to the recovery device 57 side during printing standby, and the recording head 34 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When ejection failure occurs, the ejection port of the recording head 34 is sealed with a capping unit, bubbles are sucked out together with ink from the ejection port with a suction unit through a tube, and ink or dust adhering to the ejection port surface is cleaned. It is removed by the means and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

It is sectional drawing which shows the inkjet head of Example 1 to which this invention is applied. It is a perspective view which decomposes | disassembles and shows the inkjet head shown in FIG. It is sectional drawing which shows each individual liquid chamber of the flow-path board of an inkjet head typically, and cross-sections. It is sectional drawing which shows typically the 1st removal method which removes the foreign material generated during the manufacture process of an inkjet head. It is sectional drawing which shows typically the example when a foreign material cannot be removed in a 1st removal method. It is sectional drawing which shows typically the 2nd removal method which removes the foreign material which generate | occur | produced during the manufacture process of the inkjet head. It is sectional drawing which shows the principal part structure of the inkjet recording device of Example 2 to which this invention is applied. It is side surface sectional drawing of the inkjet recording device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Channel plate, 1a ... Through-hole, 1b ... Individual liquid chamber, 1c ... Common liquid chamber, 1d ... Fluid resistance part, 1e ... Pressurized liquid chamber, 2 ... Nozzle plate, 2a ... Nozzle, 3 ... Vibration plate, DESCRIPTION OF SYMBOLS 4 ... Base member, 5 ... Piezoelectric element, 6 ... Frame member, 6a ... Common ink flow path, 7 ... Filter, 8 ... Liquid discharge port, 10 ... Foreign substance, 21 ... Recording apparatus main body, 22 ... Printing mechanism part, 23 ... Paper, 24... Paper cassette, 26... Discharge tray, 31... Main guide rod, 32 .sub.guide rod, 33 .. carriage, 34 .. recording head, 35 .. ink cartridge, 37. , 41... Paper feed roller, 44... Transport roller, 47 .. sub-scanning motor, 49... Printing receiving member, 53.

Claims (7)

  Corresponding to the pressure liquid chamber, a flow path plate having a common liquid chamber and a plurality of pressurized liquid chambers, a nozzle plate having discharge holes corresponding to the plurality of pressurized liquid chambers and joined to the flow path plate An ink jet head comprising a drive element formed as described above, wherein the flow path plate is provided with a liquid discharge port having a sufficiently small fluid resistance as compared with the discharge hole.   2. The ink jet head according to claim 1, wherein the fluid resistance of the liquid discharge port is about 1/10 of the fluid resistance of one discharge hole.   The inkjet head according to claim 1, wherein a plurality of the liquid discharge ports are formed in the flow path plate.   The inkjet head according to claim 1, wherein an opening area of the liquid discharge port is larger than a total opening area of the plurality of ejection holes.   The ink jet head according to claim 1, wherein the liquid discharge port is closed when the nozzle plate is joined to the flow path plate.   6. The ink jet head according to claim 1, further comprising a filter for preventing entry of foreign matter upstream of the pressurized liquid chamber of the flow path plate.   7. An ink jet recording apparatus for recording an image on a recording medium by ejecting ink droplets from an ejection hole by energy generated by an actuator driven in accordance with a recording signal, comprising the ink jet head according to claim 1. An ink jet recording apparatus comprising: a carriage; and an ink storage member for supplying ink to the ink jet head.