JP3890820B2 - Inkjet head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet head, and more particularly to an ink jet head used in an ink jet type printing apparatus that prints on a recording medium by ejecting ink.
[0002]
[Prior art]
Today, instead of the conventional impact printing devices, the non-impact printing devices that are expanding the market are the simplest in principle and easy to multi-tone and color. As an example, an ink jet printing apparatus can be given.
[0003]
In general, in an ink jet printing apparatus, an ink cartridge for storing ink to be supplied to an ink jet head is provided in a replaceable manner. Fine air bubbles and dust may adhere to the inner wall surface of the ink flow path from the ink cartridge to the nozzle hole of the ink jet head, and the ink quality is poor due to the air bubbles and dust. May decrease.
[0004]
Therefore, it is known to perform a purge operation in order to perform initial introduction of ink from the ink cartridge to the inkjet head when the ink cartridge is replaced, and to recover and maintain the ink ejection function of the inkjet head. In the purge operation, a large negative pressure is generated by a suction pump connected to the suction cap while the suction cap is in contact with the nozzle surface of the inkjet head, and a predetermined amount of ink inside the inkjet head together with bubbles and dust is passed through the suction cap. By sucking, the ink flow path is filled with ink, and bubbles and dust in the ink flow path are discharged to the suction cap side.
[0005]
By the way, when the user first installs the ink cartridge in a new printer when using the ink jet printer, the ink flow path is filled with air. When the ink cartridge is replaced, air has entered between the ink cartridge and the inkjet head. In addition, when the user misjudges that the ink cannot be ejected and the purge operation is performed to recover the ejection function when the remaining amount of ink is low, the ink in the ink jet head runs out and the ink flow path becomes A state filled with air occurs.
[0006]
When performing a purge operation in a state where there is air in the ink flow path, if a large negative pressure is applied at a stretch and ink is rapidly sucked, the ink and air mix and flow into the inkjet head. The ink bubbles and the ink in the ink jet head contains a large amount of bubbles.
[0007]
In particular, when a mesh-like filter member is provided at the connection portion between the ink jet head and the ink cartridge so that bubbles and dust do not move to the ink jet head side together with the ink, when the ink rapidly passes through the filter member. And a huge bubbling
Therefore, a large amount of bubbles are likely to be generated. The bubbles gradually disappear while the ink flows from the filter member to the nozzle holes of the ink jet head. However, the larger the volume of the ink flow path between the filter member and the nozzle holes, the more bubbles remain up to the nozzle holes. Increases the amount of, which adversely affects the initial introduction characteristics.
[0008]
And if there are minute bubbles in the ink flow path, especially if the ink jet head is not used in an environment where the ink easily evaporates such as high temperature and low humidity, the bubbles grow and become large. When the ink jet head is reused, the enlarged bubbles block the ink flow path and ink non-ejection (non-ejection after leaving) tends to occur, which adversely affects the ejection characteristics after leaving.
[0009]
Therefore, it is desirable to reduce the volume of the ink flow path between the filter member and the nozzle hole. However, when the filter member is provided at the connection portion between the inkjet head and the ink cartridge, It is difficult to reduce the volume. In order to reduce the volume of the ink flow path, it is conceivable to provide a filter member inside the ink jet head. However, if a mesh-like filter member is attached to the inside of the ink jet head, a large amount of attachment work is required. In addition to the time and effort, there is a risk of poor mounting.
[0010]
Accordingly, as disclosed in Japanese Patent Laid-Open No. 6-312506, an ejection port from which ink is ejected, an energy generation element that generates energy for ejecting ink from the ejection port, and the energy generation element In the ink jet head provided with a liquid flow path for supplying ink to the discharge port, at least a part of the liquid flow channel on the side opposite to the discharge port from the portion where the energy generating element is provided ( a) a structure in which a plurality of openings having a cross-sectional area smaller than the cross-sectional area of the discharge port forms a curved path; and (b) a plurality of openings having protrusions, which are formed by the openings and the protrusions. (C) a plurality of openings having a cross-sectional area smaller than the cross-sectional area of the discharge port and formed on the discharge side of the opening; Any one of a structure in which a pillar having a portion is provided with a concave surface facing the discharge port side, and (d) a structure having a cross section in which a plurality of protrusions are provided in the width direction at intervals smaller than the width of the discharge port An ink jet head having a structure (hereinafter, these structures are collectively referred to as a filter structure) has been proposed.
[0011]
According to the technique described in the publication, since the filter structure is provided, the ink supplied from the outside of the inkjet head is ejected from the ejection port through the filter structure. At this time, if dust larger than the cross-section or width of the ejection port is present in the ink, the dust is blocked by the filter structure, so that ink ejection failure due to clogging of the dust near the ejection port is suppressed.
[0012]
[Problems to be solved by the invention]
In the above publication, the filter structure of (a) has a substantially square section (see FIG. 14), a rectangular section (see FIG. 15), and a cross shape (see FIG. 16). In this example, a plurality of the column portions are arranged uniformly. And the thing which has arrange | positioned the some parallel column part with the long rectangular cross section with respect to the arranged discharge outlet is described.
[0013]
In addition, the above publication describes that the filter structure of (b) has a needle-like protrusion and a column section having a rectangular cross section (see FIG. 18 of the publication), and the filter structure of (c) has a concave section. One having a letter-shaped column (see FIG. 28 in the publication) is described, and one having a plurality of needle-like protrusions (see FIG. 36 in the publication) is described as the filter structure of (d).
[0014]
However, the filter structure is fine, and the bottom surface area of the column portion is very small when the column portion has a substantially square cross-section, a cross-shaped cross section, or a concave cross-section. In
For this reason, it is difficult to increase the fixing strength of the column portion with respect to the ink flow path, and the column portion may fall when the ink suddenly flows due to a large negative pressure in the purge operation. When the column part falls down, the cross-sectional shape of the ink flow path changes, so that the ink ejection characteristics may change and printing unevenness may occur. .
[0015]
Further, when a plurality of the column portions are arranged uniformly, the flow resistance of the ink is increased, and the ink ejection characteristics are deteriorated, which may make high-speed printing impossible. In particular, when a plurality of columnar sections having a rectangular cross section are arranged substantially parallel to the aligned discharge ports, the flow resistance of the ink is significantly increased, so that the ink ejection characteristics are liable to be deteriorated.
[0016]
In addition, when the needle-like protrusion is used, the area of the bottom surface of the needle-like protrusion is smaller than that of the column portion. Therefore, it is very important to increase the fixing strength of the needle-like protrusion with respect to the ink flow path. It is difficult, and when the ink suddenly flows due to a large negative pressure in the purge operation, the needle-like projections may fall down and the ink ejection characteristics may change.
[0017]
Furthermore, when ink is supplied from the ink supply source through the filter structure over the entire length of the row formed by the multiple ejection channels, bubbles and dust tend to stay in the end portion of the filter structure. When air bubbles or dust that stays in this way or is trapped by the filter structure grows, the filter structure is partially blocked, causing printing unevenness. These bubbles and dust are difficult to remove even by a powerful suction purge.
[0018]
The present invention has been made to solve the above-described problems, and its purpose is to prevent defective ejection due to ink bubbles and dust, and to perform normal printing. An object of the present invention is to provide an ink jet head capable of discharging dust well.
[0019]
[Means for Solving the Problems]
In order to achieve this object, the invention according to claim 1 is characterized in that a plurality of channels for containing ink are formed in an aligned state, and the ink in the channel is provided on the outlet end side of the channel. An actuator that is driven to eject liquid droplets from a nozzle hole, and is connected to an inlet end side of the plurality of channels, extends in an alignment direction of the plurality of channels, and supplies ink supplied from an ink supply source. An inkjet head having a manifold formed with an ink supply path to be supplied to each inlet end of the plurality of channels, wherein the channel at the end in the alignment direction of the plurality of channels is a channel dedicated to the flushing operation Each inlet end of the plurality of channels excluding the channel dedicated to the flushing operation, In the ink supply path between the wall surface of the ink supply path of the manifold facing the mouth end, fill opening the respective inlet end and an interval of the plurality of channels T An opening forming member is provided in the ink supply path to form an opening facing the channel; and the opening forming member adjacent to the opening facing the channel dedicated to the flushing operation is the fill. And It is the gist of being extended so as to be connected.
[0020]
According to a second aspect of the present invention, in the inkjet head according to the first aspect, the fill T A substantially long cylindrical shape You Multiple Filter member Are arranged at predetermined intervals.
[0021]
According to a third aspect of the present invention, in the ink jet head according to the second aspect, the
The plurality of filter members are arranged in a plurality of rows in parallel with the alignment direction of the plurality of channels, the filter members in one row are arranged corresponding to the gaps between the filter members in the other row, and the filter members in each row Make sure that the semicircular ends are spaced from each other.
It is a summary.
[0022]
According to a fourth aspect of the present invention, in the ink jet head according to the second or third aspect, the extended opening forming member is the end of the filter member in the alignment direction of the plurality of channels. It is the gist that it is connected.
[0023]
According to a fifth aspect of the present invention, in the ink jet head according to any one of the first to fourth aspects, there are a plurality of the opening forming members, and openings corresponding to the plurality of channels are provided in the gaps. It is the gist of having a part.
[0024]
According to a sixth aspect of the present invention, in the ink jet head according to the fifth aspect, the actuator includes a plurality of channels for accommodating the ink and dummy channels formed alternately in an aligned state, and the opening forming member. The main point is that they are arranged opposite to the dummy channel.
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
[0039]
[0040]
[0041]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a schematic configuration of a color inkjet printer 1 including an inkjet head 600 according to the present embodiment.
[0042]
The guide rod 501 and the guide member 502 are fixed to the printer frame 503. The carriage 504 is slidably supported by the guide rod 501 and the guide member 502, fixed to the belt 505, and driven by the carriage motor 506 to reciprocate. The belt 505 is wound around pulleys 507 arranged in the vicinity of both ends of the elongated guide rod 501 and the guide member 502. One pulley 507 is connected to the drive shaft of the carriage motor 506.
[0043]
A head unit 508 in which two sets of inkjet heads 600 are arranged side by side is attached to the carriage 504. Each inkjet head 600 is connected to a drive control circuit (not shown) described later. An ink cartridge 509 that supplies ink to nozzle holes (not shown), which will be described later, is detachably mounted on the rear portion of each inkjet head 600.
[0044]
The printing paper P is conveyed as a recording medium to a position facing the inkjet head 600.
A transport mechanism LF is disposed. The transport mechanism LF transports the printing paper P by the rotation of the platen roller 511 that is rotated by driving the transport motor 510. A roller shaft 512 of the platen roller 511 is rotatably supported by the printer frame 503.
[0045]
As described above, in the color inkjet printer 1, the reciprocating movement of the carriage 504 and the conveyance of the printing paper P cooperate to eject ink droplets from the inkjet head 600 to a desired area on the printing paper P. Print as desired. Since the color ink jet printer 1 performs color printing with four color inks (cyan, magenta, yellow, and black), the ink cartridge 509 stores four color inks. As described later, since the inkjet head 600 is configured to eject two color inks independently, two sets of inkjet heads 600 are provided for four color inks.
[0046]
Further, the color inkjet printer 1 is provided with a maintenance / recovery mechanism RM for maintaining / recovering the ink ejection operation of the inkjet head 600. The maintenance / recovery mechanism RM includes a purge device 513 and a flushing ink absorbing member 516.
[0047]
The purge device 513 is disposed on the side of the platen roller 511 so as to face the inkjet head 600 in a reset state. The purge device 513 generates a large negative pressure by the suction pump 515 connected to the suction cap 514 in a state where the suction cap 514 is in contact with the nozzle surface of the inkjet head 600, and the inside of the inkjet head 600 is passed through the suction cap 514. A purging operation is performed in which a predetermined amount of ink is sucked together with bubbles and dust. By this purging operation, it becomes possible to eliminate the ejection failure caused by bubbles and dust remaining in the ink jet head 600, and it is possible to achieve a good recovery of the ejection state.
[0048]
The flushing ink absorbing member 516 is made of a porous material plate having excellent ink absorbability, and is disposed on the side of the platen roller 511 opposite to the purge device 513 so as to face the inkjet head 600 in a reset state. Yes. Before the ink is ejected from the inkjet head 600 to the printing paper P, a flushing operation is performed in which the ink is ejected from the inkjet head 600 to the flushing ink absorbing member 516. This flushing operation makes it possible to discharge bubbles and dust remaining inside the inkjet head 600 together with the ink to the flushing ink absorbing member 516. Therefore, coupled with the purge operation, the ejection failure is eliminated and a good ejection state is achieved. Recovery can be achieved.
[0049]
FIG. 2 is a perspective view showing the inkjet head 600. The ink jet head 600 includes substrates 11 and 12 having piezoelectric elements, manifold members 13 and 14, a plate member 15, and a nozzle plate 16.
[0050]
Flat plate rectangular substrates 11 and 12 are attached and fixed to both sides of the front portion of the flat plate member 15, and flat plate manifold members 13 and 14 are attached and fixed to both rear portions of the plate member 15. Yes. That is, the plate member 15 is extended to the rear end side with respect to the substrates 11 and 12, and is formed at each corner portion formed by both side surfaces of the extension portion of the plate member 15 and the rear end surfaces of the substrates 11 and 12. The front ends of the manifold members 13 and 14 are connected. Each substrate 11, 12, plate member 15, and nozzle plate 16 constitute an actuator 24.
[0051]
The front end surfaces of the substrates 11 and 12 and the plate member 15 are flush with each other, and a flat plate-like nozzle plate 16 is stuck and fixed so as to close the front end surfaces. Each substrate 11, 12 and each substrate
An appropriate material (for example, for example, a rear end portion of each substrate 11, 12, an outer peripheral portion of each manifold member 13, 14, a rear portion of the plate member 15) between the nihold members 13, 14 and the plate member 15 is used. A sealing material 17 made of silicon rubber or the like is applied, and the manifold members 13 and 14 are fixed to the substrates 11 and 12 and the plate member 15 by the sealing material 17, and ink from the manifold members 13 and 14 is used. Leakage is prevented.
[0052]
A plurality of lead-out grooves 21 connected to and communicated with dummy grooves (not shown) to be described later are formed at the front end portions of the substrates 11 and 12. A circular ink supply hole 22 is formed in the lower part of each manifold member 13, 14. FIG. 3 is a perspective view showing a state where the sealing material 17 is removed from the inkjet head 600.
[0053]
A plurality of introduction grooves 23 connected to and communicated with dummy grooves, which will be described later, are formed at the front end portions of the manifold members 13 and 14. As shown in FIG. 2, each introduction groove 23 is sealed with a sealing material 17. FIG. 4 is a partial vertical cross-sectional view of the inkjet head 600, and is a cross-sectional view taken along line YY in FIG.
[0054]
FIG. 5 is a perspective view showing a state in which a part of each of the substrates 11 and 12 is viewed from the front end side. 6 is a cross-sectional view of the inkjet head 600, and is a cross-sectional view taken along line XX in FIG.
[0055]
FIG. 7 is an exploded perspective view showing a state where the manifold members 13 and 14 are removed from the inkjet head 600. FIG. 8 is a perspective view showing a state in which a part of the manifold member 14 is viewed from the back surface (surface connected to the plate member 15) side.
[0056]
FIG. 9 is a plan view showing the back side of a part of the manifold member 14 and the substrate 12. FIG. 10 is a plan view showing the back side of the manifold member 13. FIG. 11 is a plan view showing the back side of the manifold member 14.
[0057]
4 to 9 are schematic diagrams for explaining the configuration of the ink jet head 600, and there are places where the dimensions of each member of the ink jet head 600 do not match between the drawings. This is to make the configuration easy to understand. 10 and 11 show actual manifold members 13 and 14, and therefore there are places where the dimensional shapes of the members do not match those of FIGS.
[0058]
As shown in FIGS. 4 and 5, on the back surface (surface connected to the plate member 15) side of each of the substrates 11 and 12, a straight groove shape is formed in parallel with the transverse sectional direction of the ink jet head 600 shown in FIG. A plurality of channel grooves 31 and dummy grooves 32 are formed in an alternately aligned state. The open top of each channel groove 31 and each dummy groove 32 is covered with a plate member 15, and the ejection channel of the actuator 24 is formed by the channel groove 31 covered with the plate member 15. A dummy channel of the actuator 24 is formed by the dummy groove 31 covered by the above.
[0059]
The side walls of each channel groove 31 and each dummy groove 32 are formed of a shear mode type upper wall 33 and lower wall 34 made of a suitable piezoelectric material (for example, piezoelectric ceramics) polarized in the opposite direction. . That is, the upper wall 33 is connected to the plate member 15 and is polarized in the direction of the plate member 15 (arrow A direction). The lower wall 34 is connected to the bottoms of the grooves 31 and 32 and is polarized in the direction opposite to the polarization direction of the upper wall 33 (in the direction of arrow B).
[0060]
An electrode 35 is formed on the inner wall surface including the bottom of each channel groove 31, and the bottom of each dummy groove 32 is formed.
Electrodes 36 are formed on both side wall surfaces excluding the portion. The electrodes 35 provided in the channel grooves 31 are grounded, and the electrodes 36 provided in the dummy grooves 32 are connected to the drive control circuit 37, respectively. The drive control circuit 37 generates a drive signal and applies it to each electrode 36.
[0061]
As shown in FIGS. 4 and 6, nozzle holes 16 a are formed at the outlet ends of the channel grooves 31 in the nozzle plate 16. As shown in FIG. 6, when the substrates 11 and 12 are connected to both surfaces of the plate member 15, the plurality of channel grooves 31 formed in the substrates 11 and 12 are aligned in two rows. Two independent channel groups are configured by the channel grooves 31 arranged in each row. Further, each channel groove 31 and each dummy groove 32 are formed to fill the width direction of each substrate 11, 12, and both end portions of each channel groove 31 and each dummy groove 32 are opened from both end surface sides of each substrate 11, 12. ing. The front end portion of each dummy groove 32 is connected to and communicated with each lead-out groove 21 of each substrate 11 and 12, and the rear end portion of each dummy groove 32 is connected and communicated to each introduction groove 23 of each manifold member 13 and 14. Each introduction groove 23 is filled with a sealing material 17. The sealing material 17 in the introduction groove 23 is for preventing ink supplied from an ink supply path 41 (described later) to the channel groove 31 from leaking into the dummy groove 32. In FIG. 6, the sealing material 17 is also filled in the dummy groove 32. This is because the liquid sealing material placed outside the manifold member is introduced into the introduction groove 23 by vacuum suction from the lead-out groove 21 side. When the inside is filled, it also flows into the dummy groove 32, which is not necessary.
[0062]
As shown in FIGS. 6 to 11, each manifold member 13, 14 is formed with an ink supply path 41 composed of a recess formed at a certain depth in the plate thickness direction of each manifold member 13, 14. Yes. An ink supply hole 22 is formed in the start end portion 41 b of the ink supply path 41 of each manifold member 13, 14, and an opening forming member 42, a filter member 43, and a rib-like protrusion 44 are formed in each ink supply path 41. ing. The ink supply paths 41 of the manifold members 13 and 14 are formed in a symmetric structure with respect to the plate member 15 including the members 42 to 44 inside the manifold members 13 and 14.
[0063]
As shown in FIGS. 7, 10, and 11, the planar shape of the ink supply path 41 is from the start end 41 b (lower part of the ink supply path 41) where the ink supply hole 22 is formed to the final end 41 a (ink supply path). The width is gradually narrowed toward the upper portion of 41 and extends in the alignment direction of the channel grooves 31 of the substrates 11 and 12. One side portion of the ink supply path 41 opens in common to the inlet ends of the channel grooves 31 of the substrates 11 and 12, and a plurality of opening forming members 42 are provided in the opening portions. Yes.
[0064]
As shown in FIGS. 7 to 11, each opening forming member 42 has a substantially semi-spindle cross section, and an opening 45 is formed by a gap between each opening forming member 42. Each opening forming member 42 is connected to the inlet end side of each channel groove 31 in each substrate 11, 12. Each opening forming member 42 is disposed to face each dummy groove 32, and each opening 45. Are arranged opposite to each channel groove 31 and connected to each other. In addition, an introduction groove 23 is formed on the end face of each opening forming member 42 on the side of the substrate 11, 12, and one end of each introduction groove 23 opens to the outside of each manifold member 13, 14. The other end is connected to and communicated with the rear end portion of each dummy groove 32.
[0065]
As shown in FIGS. 7 to 11, in each manifold member 13, 14, each opening 45 (inlet end of each channel groove 31) between each opening forming member 42 and ink supply facing each opening 45. Between the wall surface 41c of the path 41, filter members 43a and 43b having a long cylindrical shape are formed. The filter members 43a and 43b are arranged in two rows parallel to the alignment direction of the openings 45, and the filter members 43a in the row closer to the opening formation members 42 form the openings.
Each filter member 43b in the row arranged corresponding to the member 42 and closer to the wall surface 41c of the ink supply path 41 is arranged corresponding to each opening 45. That is, each filter member 43a is arranged corresponding to a gap between each filter member 43b. And each filter member 43a is arrange | positioned at predetermined intervals t from the front-end | tip part of each opening part formation member 42. FIG. Further, the semicircular ends of the filter members 43a and 43b are arranged close to each other, and the gap between the ends is formed narrow so as to prevent the flow of minute bubbles and dust. The filter members 43 a and 43 b are formed perpendicular to the bottom surface of the ink supply path 41 and the plate member 15.
[0066]
Each of the filter members 43 a and 43 b has a portion corresponding to two openings 45 a and 45 b (inlet ends of the two channel grooves 31) located at the final end 41 a of the ink supply path 41, and the ink supply path 41. It is not provided in a portion corresponding to the opening 45c (inlet end of the channel groove 31) located at the start end 41b. That is, the filter members 43a and 43b are not disposed in the vicinity of the inlet ends at both ends of the channel grooves 31 in the alignment direction. The opening forming members 42a and 42b adjacent to the openings 45b and 45c are extended and connected to the filter member 43a.
[0067]
As shown in FIGS. 7, 10, and 11, in each manifold member 13, 14, each opening 45 (inlet end of each channel groove 31) between each opening forming member 42 is opposed to each opening 45. A thin plate for guiding ink from the ink supply hole 22 toward the alignment direction end of each opening 45 (alignment direction end of the plurality of channel grooves 31) between the wall 41c of the ink supply path 41 Each rib-shaped protrusion 44a-44h which comprises a shape is extended. That is, among the plurality of rib-shaped protrusions 44 a to 44 h, the rib-shaped protrusions 44 g and 44 h are arranged between the ink supply hole 22 and each opening 45, and the other rib-shaped protrusions are connected to the ink supply hole 22. Two rows are arranged at intervals toward the alignment direction end of each opening 45, and each rib-like projection 44b, 44d, 44f in one row is each rib-like projection 44a, 44c, 44e in the other row. , 44g, 44h are arranged corresponding to the gaps. Each of the rib-like protrusions 44a to 44h is located at a distance from the wall surface 41c of the ink supply path 41, and forms a flow path from the ink supply hole 22 toward the final end of the ink supply path 41 therebetween. . The rib-like protrusion 44a in the vicinity of the final end 41a of the ink supply path 41 guides the flow of ink to the openings 45a and 45b at the final end and at the opening adjacent to the start end of the opening. Is also positioned to guide the ink. Also, the rib-like protrusion 44h in the vicinity of the start end portion 41b is positioned so as not to hinder the flow of ink from the ink supply hole 22 to the opening portion 45c at the start end portion. The rib-shaped protrusions 44 a to 44 h are formed perpendicular to the bottom surface of the ink supply path 41 and the plate member 15.
[0068]
The top portions of the opening forming members 42, the filter members 43, and the rib-like projections 44 are connected and fixed to the plate member 15 in a liquid-tight manner. Each manifold member 13, 14 is integrally formed with an ink supply path 41, an opening forming member 42, a filter member 43, and a rib-like protrusion 44 by injection molding of a synthetic resin material.
[0069]
By the way, the ink jet head 600 is attached to the carriage 504 in a horizontally horizontal state as shown in FIG. 1, and the ink supply holes 22 of the manifold members 13 and 14 are arranged on the lower side in this state. The ink jet head 600 may be disposed at an angle of about 45 ° with respect to the main body of the color ink jet printer 1 with the nozzle plate 16 facing downward and the manifold members 13 and 14 facing upward. The ink jet head 600 may be arranged vertically downward with respect to the main body of the color ink jet printer 1 with the nozzle plate 16 facing downward.
[0070]
Next, the operation and effect of the present embodiment configured as described above will be described. Each color ink stored in the ink cartridge 509 shown in FIG. 1 is independently supplied to the ink supply holes 22 of the manifold members 13 and 14, and the ink supply holes 22 of the manifold members 13 and 14 → the manifolds. The ink is supplied into the channel grooves 31 through the ink supply paths 41 of the members 13 and 14, the openings 45 of the manifold members 13 and 14, and the channel grooves 31 of the substrates 11 and 12.
[0071]
Here, the channel grooves 31 formed in the substrates 11 and 12 are completely separated by the extension of the plate member 15. Accordingly, when connecting the manifold members 13 and 14 to the rear end surfaces of the substrates 11 and 12, respectively, the channel grooves 31 between the substrates 11 and 12 which are ink flow paths of different colors, even in rough operations. In addition, the ink supply paths 41 between the manifold members 13 and 14 are not connected to each other, and different color inks are not mixed. For this reason, it is possible to prevent ink from mixing between two independent channel groups formed by the channel grooves 31 formed in the substrates 11 and 12, and to perform reliable color separation. .
[0072]
Then, as shown in FIG. 4, in a state where ink is supplied into each channel groove 31, an electrode 36 on the channel groove 31a side in two dummy grooves 32 sandwiching an arbitrary channel groove 31a is applied from the drive control circuit 37. When a drive signal of a predetermined voltage E (V) is applied, electric fields in the directions of arrows C and D are generated on the side walls (upper wall 33 and lower wall 34) of the channel groove 31a sandwiched between the dummy grooves 32, respectively. Then, the side wall portion of the channel groove 31a is deformed in a piezoelectric thickness direction so as to increase the volume of the channel groove 31a. Then, the pressure in the channel groove 31a including the vicinity of the nozzle hole 16a decreases.
[0073]
Here, when the application of the drive signal from the drive control circuit 37 is maintained for the one-way propagation time T of the pressure wave in the channel groove 31a, ink is supplied from the ink cartridge 509 to the channel groove 31a through the path during that period. The The one-way propagation time T is the time for the pressure wave of the ink in the channel groove 31 to propagate one-way in the longitudinal direction of the channel groove 31, and the length L of the channel groove 31 shown in FIG. Is calculated by the equation T = L / S.
[0074]
According to the propagation theory of the pressure wave, when the one-way propagation time T elapses from the application of the drive signal, the pressure in the channel groove 31a is reversed and turned to a positive pressure. Return to V). Then, the side wall portion of the channel groove 31a returns to the state before deformation, and pressure is applied to the ink. As a result, the positive pressure and the pressure generated when the side wall portion returns to the state before deformation are added together, and a relatively high pressure is generated in the vicinity of the nozzle hole 16a in the channel groove 31a. Ink droplets are ejected from 16a.
[0075]
Here, if a material having flexibility (for example, silicon rubber) is used as the sealing material 17 filled in the dummy grooves 32, the side wall portion even in a state where each dummy groove 32 is filled with the sealing material 17. Therefore, the volume change of the channel groove 31a at the time of ink ejection is not hindered.
[0076]
In the present embodiment, each ejection channel corresponding to the opening portions 45a to 45c of the ink flow channel 41 at the start end portion 41b and the final end portion 41a is provided exclusively for the flushing operation. That is, during the printing operation on the printing paper, the carriage 504 is moved to a position opposed to the flushing ink absorbing member 516 at regular intervals, and ink is ejected from the flushing ejection channel, whereby the ink supply path 41 Ink that easily stagnates in the vicinity of the end portions 41a and 41b can be discharged. In addition, an ink flow is generated between the rib-shaped protrusions 44 a to 44 h and the wall surface of the ink supply path 41, and air bubbles and dust trapped by the filter member 43 are also discharged. can do. Further, since the ink flow does not receive the resistance of the filter member 43, the flow velocity can be increased, and the effect of discharging bubbles is high.
[0077]
In addition to the above-described flushing operation, performing a flushing operation for driving all the ejection channels as known in the art is effective in preventing the increase in the viscosity of the ink in the channels that are not ejected. Further, when the ink is sucked from all the ejection channels by operating the purge device 513, a high flow velocity is obtained along the wall surface of the ink supply path in the same manner as described above. Air bubbles and dust trapped by the member 43 can be effectively discharged. The suction through each of the openings 45 except for the openings 45a to 45c at the end also passes through the plurality of rib-like protrusions 44a to 44h, so that the ink is supplied to the entire ink supply path 41 together with the suction through the openings 45a to 45c. Can be generated. Therefore, the ink introduction property is very good in the initial introduction after the ink cartridge replacement or the purge operation at regular intervals.
[0078]
Even during a normal printing operation, the ink is supplied through the plurality of rib-shaped protrusions 44a to 44h by the operation of the ejection channels corresponding to the openings 45 except for the openings 45a to 45c at the end, thereby A high flow velocity is obtained along the wall surface of the supply path, and microbubbles are easily discharged along with ink ejection. Therefore, the bubbles are less likely to stagnate and grow.
[0079]
Conventionally, attempts have been made to reduce the cross-sectional area of the ink supply path in order to improve the ink introduction property and the air bubble discharge property. However, in this case, there is a problem in that crosstalk occurs. However, by configuring as described above, it is possible to sufficiently secure the cross-sectional area of the ink supply path while improving the ink introduction property and the bubble discharge property, and as a result, the crosstalk can also be improved. It was.
[0080]
In the above embodiment, each ejection channel corresponding to the openings 45a to 45c of the end portions 41a and 41b of the ink flow path 41 is dedicated to the flushing operation. However, even if all ejection channels are used for the printing operation, Similar effects can be obtained. That is, in this case, (1) the ejection channel corresponding to the opening portions 45a to 45c at the end portion may be used for printing with the above-described configuration, but (2) the filter member 43 is used as the opening portions 45a to 45c at the end portion. Alternatively, all the filter members 43 may be eliminated and ink may be supplied to all the ejection channels with the same resistance.
[0081]
In the case of (1), as described above, a high-speed ink flow is generated between the rib-like protrusions 44a to 44h and the wall surface of the ink supply path 41 by ink ejection (including flushing) or suction purge. Air bubbles and dust that stay in the vicinity of the end portion 41a or are trapped by the filter member 43 can be effectively discharged. In the case of (2), even if the pressure acting on all the openings 45 (including 45a to 45c) is the same, the rib-like projections 44a to 44h and the ink supply path are present due to the presence of the rib-like projections 44a to 44h. The flow of ink toward the final end portion 41a is ensured between the wall surface 41 and the air bubbles and dust trapped in the vicinity of the final end portion 41a and trapped by the filter member 43 can be effectively discharged.
[0082]
As described above, the ink supplied through the ink supply path 41 passes through the filter members 43a and 43b, and is located on the side of the opening 45 between the opening forming members 42 (the inlet end side of each channel groove 31). Sent to. Therefore, when air bubbles and dust are contained in the ink, first, relatively large air bubbles and dust are blocked by the filter members 43b, and thereafter, minute air bubbles and dust are respectively removed from the filter members 43a and 43b. It is blocked by the semicircular ends. That is, since each filter member 43a, 43b functions as an ink filter, it is possible to avoid air bubbles and dust being sent to each opening 45 and to eject ink by clogging the air bubbles and dust in the vicinity of each opening 45. Defects can be prevented.
[0083]
Further, by setting the distance t between the tip of each opening forming member 42 and the filter member 43a to be narrow, the volume of the ink flow path between each filter member 43a, 43b and each nozzle hole 16a is reduced. Since the amount of bubbles generated when ink passes through the filter members 43a and 43b can be reduced to the nozzle holes 16a, the initial introduction characteristics and the ejection characteristics after being left standing can be improved. .
[0084]
Further, by forming the filter members 43a and 43b integrally with the manifold members 13 and 14, it is possible to reduce the number of components of the ink jet head 600 and eliminate the need for mounting the filter members 43a and 43b. Therefore, in addition to reducing the manufacturing cost, it is also possible to avoid the mounting failure of the filter members 43a and 43b.
[0085]
Since each of the filter members 43a and 43b has a substantially long cylindrical shape, the column having the shape (substantially square shape in cross section, cross shape in cross section, concave shape in cross section) in the above-mentioned publication (Japanese Patent Laid-Open No. 6-31506). Compared to the portion, the area of the bottom surface of each filter member 43a, 43b can be increased to increase the fixing strength with respect to the ink supply path 41, so that the ink flows rapidly due to a large negative pressure in the purge operation. In this case, the filter members 43a and 43b can be prevented from falling down. Accordingly, since the filter members 43a and 43b are not tilted and the cross-sectional shape of the ink supply path 41 is not changed, it is possible to perform normal printing by preventing the occurrence of printing unevenness due to the change of the ink ejection characteristics. it can.
[0086]
Further, the intervals between the filter members 43a and the intervals between the filter members 43b are made wide enough to avoid an increase in the flow resistance of the ink, and then the semicircular end portions of the filter members 43a and 43b are used. The distance between them can be made narrow enough to prevent the flow of minute bubbles and dust. Therefore, the flow resistance of the ink passing through the filter members 43a and 43b can be lowered without deteriorating the function of the filter members 43a and 43b as a filter, and therefore the flow resistance of the ink is increased. It is possible to realize high-speed printing by preventing the deterioration of the jetting characteristics due to.
[0087]
Further, since the rows formed by the filter members 43a are arranged corresponding to the rows formed by the openings 45, the ink that has passed through the filter members 43a flows smoothly toward the openings 45, so that the flow of ink An increase in resistance can be avoided. As described above in detail, according to the present embodiment, since the filter members 43a and 43b having the above-described configuration are provided, it is possible to solve the problems of the publication (Japanese Patent Laid-Open No. 6-31506). Accordingly, it is possible to prevent normal ejection of ink from the inkjet head 600 and perform normal printing.
[0088]
Next, a method for creating the manifold members 13 and 14 will be described with reference to FIGS. First, as shown in FIG. 12, the conductive layer 101 is formed on the upper surface of the substrate 100 by plating, PVD, or the like. This conductive layer 101 becomes an electrode for electroforming in a later step. Note that the conductive layer 101 may be omitted by forming the substrate 101 with a conductive material.
[0089]
A resist material 102 is placed on the upper surface of the conductive layer 101 and baked to adhere the resist material 102 to the conductive layer 101 by thermal welding. The resist material 102 is a positive type or negative type resist and is formed to have a thickness substantially corresponding to the depth of the manifold members 13 and 14 in the ink supply path 41 with respect to the plate thickness direction.
[0090]
The resist material 102 is irradiated with a parallel light beam 105 through a mask 103. The mask 103 has a light transmission window corresponding to the planar shape of the ink supply path 41 at a position corresponding to the ink supply path 41, and a portion excluding the ink supply path 41 (opening forming member 42, filter member 43, It has a light-impermeable portion 104 corresponding to the planar shape of the rib-like projections 44). In this case, the exposed portion of the resist material 102 is removed in a later step, but conversely, when the unexposed portion of the resist material 102 is removed, the non-transparent portion 104 is disposed on the plane of the ink supply path 41. The transmission window is provided corresponding to the shape of the opening portion forming member 42, the filter member 43, and the rib-like protrusion 44.
[0091]
Here, it is desirable to use synchrotron radiation as the light beam 105 and an acrylic material as the resist material 102. Synchrotron radiation is a parallel beam of X-rays such as charged particle storage ring radiation. For this reason, even if the coating film of the resist material 102 is thick, it is exposed in parallel to the thickness direction as shown by the broken line 102a in FIG. 12, and as a result, the exposed portion 102b and the unexposed portion as shown in FIG. The exposed portion 102c is formed with high accuracy. As a result, the ink supply path 41 can be formed to a sufficient depth, and the opening forming member 42, the filter member 43, and the rib-like protrusion 44 can be formed in a desired shape.
[0092]
Thereafter, when development is performed with a developer, the exposed portion 102b is dissolved and removed in the developer, and only the unexposed portion 102c remains on the substrate 100 as shown in FIG. The unexposed portion 102 c has a shape corresponding to the opening forming member 42, the filter member 43, and the rib-shaped protrusion 44. Then, as shown in FIG. 15, a mold 106 is formed on the substrate 100 and the unexposed portion 102c by electroforming in which the conductive layer 101 on the substrate 100 is used as an electrode and the metal in the solution is deposited on the conductive layer 101. A metal material is deposited. Here, the metal that forms the mold 106 is formed to a height that completely covers at least the unexposed portion 102c of the resist. Subsequently, when the substrate 100, the conductive layer 101, and the unexposed portion 102c are removed, a molding die 106 is formed as shown in FIG. By producing the mold 106 in this manner, a precise mold 106 having a desired shape can be easily obtained.
[0093]
The conductive layer 101 is not provided in advance on the substrate 100, and the resist material 102 is developed and formed into a predetermined pattern. Then, a conductive layer is formed on the substrate 100 and the resist material 102 by vapor deposition or the like. Electroforming can also be performed as an electrode as described above.
[0094]
Then, as shown in FIG. 17, the molding die 106 is attached to the molding die main body portion 107, and the synthetic resin material 108 is poured into the gap between the molding die 106 and the molding die main body portion 107, as shown in FIG. In addition, the ink supply path 41, the opening forming member 42 (not shown), the filter member 43, and the rib-like protrusion 44 (not shown) are integrally formed to form the manifold members 13 and 14 made of the synthetic resin material 108. Here, the opening forming member 42, the filter member 43, and the rib-like protrusion 44 are formed by the unexposed portion 12c, and the ink supply path 41 is formed by the exposed portion 12b.
[0095]
As described above, when the manifold members 13 and 14 are formed by the method shown in FIGS. 12 to 18, the ink supply path 41, the opening forming member 42, and the filter member are irradiated by irradiating the resist material 102 with parallel light rays. 43, the shape corresponding to the rib-like protrusion 44 is formed with high precision in the depth direction, and a precise mold 106 can be formed based on the shape. By using the precise molding die 106, the ink supply path 41, the opening forming member 42, the filter member 43, and the rib-like protrusion 44 having sufficient depth can be accurately formed on the manifold members 13 and 14. it can. Further, since the shapes of the ink supply path 41, the opening forming member 42, the filter member 43, and the rib-shaped protrusion 44 are determined by the shapes of the non-transparent portion 104 and the transmission window of the mask 103, the shapes of the non-transmission portion 104 and the transmission window are determined. It becomes possible to freely set the shapes of the members 41 to 44 only by appropriately setting, and it becomes easy to create the fine filter members 43 and their gaps in an accurate shape.
[0096]
Further, in order to arrange the ejection channels at high density, the width of the side walls is increased by a predetermined amount in order to reduce the channel width and increase the depth, or to obtain the ink ejection pressure as in the actuator of the present embodiment. When necessary, the above manufacturing method is suitable for forming the opening forming member 42, the filter member 43, and the filter member 44 at a sufficient height.
[0097]
In addition, this invention is not limited to the said embodiment, You may change as follows, and even in that case, the effect | action and effect equivalent to or more than the said embodiment can be acquired. (1) The above embodiment is embodied in the ink jet head 600 provided with the piezoelectric elements on the substrates 11 and 12, but the ink jet heads of other systems (for example, a thermal jet system using a heating element). You may apply to.
[0098]
(2) In the above embodiment, the channel grooves 31 are formed on the two substrates 11 and 12 respectively, and the channel grooves 31 are embodied in the inkjet head 600 in two rows. Either one may be omitted and the channel grooves 31 may be formed in only one row, or the channel grooves may be formed in three or more rows using three or more substrates.
[0099]
Here, as in the above embodiment, 31 rows of channel grooves are formed in each of the substrates 11 and 12, both rows are arranged close to each other, and the ink supply path 41 is arranged in each row of the plurality of channel grooves 31. In the case where the ink supply path 41 is formed, the cross-sectional area of the ink supply path 41 cannot be increased so much that bubbles and dust cannot stay in the ink supply path 41 for a long period of time. Since the ink is easily drawn into the channel groove 31 and stays in the channel groove 31, ink ejection failure is likely to occur. Therefore, it is important to be able to effectively remove bubbles and dust remaining in the vicinity of the final end 41a of the ink supply path 41.
[0100]
(3) Although the dummy grooves 32 are provided on both sides of each channel groove 31 in the above embodiment, the dummy grooves 32 may be omitted and only the channel grooves 31 may be adjacent to each other. (4) In the above embodiment, the ink supply path 41 is formed at a constant depth with respect to the plate thickness direction of the manifold members 13, 14, but the plate of the manifold members 13, 14 in the ink supply path 41. You may make it change the depth with respect to the thickness direction. That is, not only the width of the ink supply path 41 but also the depth of the ink supply path 41 may be changed to gradually reduce the cross-sectional area of the ink supply path 41.
[0101]
(5) In the above embodiment, the width of the ink supply path 41 is formed so as to gradually narrow from the start end 41b toward the final end 41a. You may make it constant over the edge part 41a. In other words, even when the cross-sectional area of the ink supply path 41 is made constant by optimally setting the number, size, and arrangement location of each rib-like protrusion 44 in the ink supply path 41, the ink as in the above embodiment is used. When the cross-sectional area of the supply path 41 is gradually reduced, the effect that is almost the same as that of the above embodiment can be obtained although it is slightly inferior.
[0102]
(6) In the above embodiment, the filter members 43a and 43b are arranged in two rows, but may be arranged in three or more rows. (7) In the above embodiment, the ink flows through the manifold member from one end of the ejection channel row to the other end. However, the ink supply hole 41 is provided in the center of the ink supply path 41, and both ends are arranged. You may make it flow ink toward. Accordingly, rib-like protrusions, filter members, and the like are also arranged from the ink supply hole 22 toward both ends.
[0103]
(8) In the above embodiment, the present invention is applied to a printer in which the inkjet head 600 moves reciprocally with the carriage 504. However, the present invention may be applied to a so-called line printer in which the inkjet head 600 is fixed to the main body of the color inkjet printer 1.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a schematic configuration of a color inkjet printer including an inkjet head according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating an inkjet head according to an embodiment.
FIG. 3 is a perspective view illustrating a state where a sealing material is removed from the inkjet head according to the embodiment.
FIG. 4 is a partial longitudinal sectional view of an ink jet head according to an embodiment.
FIG. 5 is a perspective view illustrating a state in which a part of each substrate in the inkjet head according to the embodiment is viewed from the front end side.
FIG. 6 is a cross-sectional view of an inkjet head according to an embodiment.
FIG. 7 is an exploded perspective view illustrating a state where a manifold member is removed from the inkjet head according to the embodiment.
FIG. 8 is a partial perspective view of a manifold member in the inkjet head according to the embodiment.
FIG. 9 is a partial plan view of a manifold member and a substrate in the inkjet head according to the embodiment.
FIG. 10 is a plan view of a manifold member in the inkjet head according to the embodiment.
FIG. 11 is a plan view of a manifold member in the inkjet head according to the embodiment.
FIG. 12 is a cross-sectional view for explaining a method for manufacturing a manifold member in the inkjet head according to the embodiment.
FIG. 13 is a cross-sectional view for explaining a method for manufacturing a manifold member in the inkjet head according to the embodiment.
FIG. 14 is a cross-sectional view for explaining a method of manufacturing a manifold member in the inkjet head according to the embodiment.
FIG. 15 is a cross-sectional view for explaining a method for manufacturing a manifold member in the inkjet head according to the embodiment;
FIG. 16 is a cross-sectional view for explaining a method for manufacturing a manifold member in the inkjet head according to the embodiment;
FIG. 17 is a cross-sectional view for explaining a method of manufacturing a manifold member in the inkjet head according to the embodiment.
FIG. 18 is a cross-sectional view for explaining a method for manufacturing a manifold member in the inkjet head according to the embodiment.
[Explanation of symbols]
509 ... Ink cartridge 600 ... Inkjet head
11, 12 ... Substrate 13, 14 ... Manifold member
15 ... Plate member 15 16 ... Nozzle plate
16a ... Nozzle hole 22 ... Ink supply hole
24 ... Actuator 31 ... Channel groove 41 ... Ink supply path
43a, 43b ... Filter members

Claims (6)

A plurality of channels for containing ink are formed in an aligned state, and an actuator that drives the ink in the channels to be ejected as droplets from nozzle holes provided on the outlet end side of the channels;
An ink supply path connected to the inlet end side of the plurality of channels, extending in the alignment direction of the plurality of channels, and supplying ink supplied from an ink supply source to each inlet end of the plurality of channels. An ink jet head comprising a manifold formed with
The channel at the end in the alignment direction of the plurality of channels is a channel dedicated to the flushing operation, the inlet ends of the plurality of channels excluding the channel dedicated to the flushing operation, and the ink supply of the manifold facing the inlet end in the ink supply path between the wall surface of the road, filters are provided at a respective inlet end and an interval of the plurality of channels,
An opening forming member for forming an opening facing the channel is provided in the ink supply path;
Ink jet head, wherein the opening forming member adjacent to the opening portion facing the channel of the flushing operation only is extended to be connected to the filter. The inkjet head according to claim 1,
The filter is an ink jet head having a plurality of filter members to growth substantially long cylindrical shape, characterized in that it is arranged at a predetermined interval. The inkjet head according to claim 2,
The plurality of filter members are arranged in a plurality of rows in parallel with the alignment direction of the plurality of channels, and the filter members in one row are arranged corresponding to the gaps between the filter members in the other row, and the filter members in each row Each of the semicircular ends of the ink jet head is disposed with a predetermined gap therebetween. In the ink jet head according to claim 2 or 3,
The extended opening forming member is connected to the end of the filter member in the alignment direction of the plurality of channels. In the inkjet head according to any one of claims 1 to 4,
2. An ink jet head according to claim 1, wherein there are a plurality of opening forming members, and openings corresponding to the plurality of channels are provided in the gaps. In the inkjet head according to claim 5,
In the actuator, a plurality of channels containing the ink and dummy channels are alternately formed in an aligned state,
The ink jet head according to claim 1, wherein the opening forming member is disposed to face the dummy channel.

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