WO2012073622A1

WO2012073622A1 - Recording device

Info

Publication number: WO2012073622A1
Application number: PCT/JP2011/074799
Authority: WO
Inventors: 和也芳村
Original assignee: 京セラ株式会社
Priority date: 2010-11-29
Filing date: 2011-10-27
Publication date: 2012-06-07
Also published as: JPWO2012073622A1

Abstract

[Problem] The purpose of the present invention is to provide a recording device, which performs control so as to transmit drive signals to pressurizing units by delaying the drive signals, and which has excellent recording accuracy at the time of forming one pixel on a recording medium using droplets jetted from a plurality of jetting holes. [Solution] The recording device has a liquid jetting head, which includes a plurality of jetting holes (8), a plurality of pressurizing chambers (10), and a plurality of pressurizing units (50), and which has a plurality of jetting hole groups (7), each of which has the jetting holes (8) disposed at equal intervals in the first direction but not aligned in the second direction that is not parallel to the first direction, and which has the jetting holes (8) that belong to one jetting hole group (7) and jetting holes (8) that belong to other jetting hole group (7) aligned with each other in the second direction. The recording device also has a transfer unit and a control unit (100). The control unit (100) delays drive signals to be transmitted to some of the pressurizing units (50), and delay presence/absence in the drive signals to be transmitted to the pressurizing units (50) of the jetting holes (8) aligned in the second direction is matched.

Description

Recording device

The present invention relates to a recording apparatus that prints an image by discharging droplets.

In recent years, printing apparatuses using inkjet recording methods such as inkjet printers and inkjet plotters are not only printers for general consumers, but also, for example, formation of electronic circuits, manufacture of color filters for liquid crystal displays, manufacture of organic EL displays It is also widely used for industrial applications.

In such an ink jet printing apparatus, a liquid discharge head for discharging liquid is mounted as a print head. This type of print head includes a heater as a pressurizing unit in an ink flow path filled with ink, heats and boiles the ink with the heater, pressurizes the ink with bubbles generated in the ink flow path, A thermal head system that ejects ink as droplets from the ink ejection holes, and a part of the wall of the ink channel filled with ink is bent and displaced by a displacement element, and the ink in the ink channel is mechanically pressurized, and the ink A piezoelectric method for discharging liquid droplets from discharge holes is generally known.

In addition, in such a liquid discharge head, a serial type that performs recording while moving the liquid discharge head in a direction (main scanning direction) orthogonal to the conveyance direction (sub-scanning direction) of the recording medium, and main scanning from the recording medium There is a line type in which recording is performed on a recording medium conveyed in the sub-scanning direction with a liquid discharge head that is long in the direction fixed. The line type has the advantage that high-speed recording is possible because there is no need to move the liquid discharge head as in the serial type.

In order to print droplets at a high density in any of the serial type and line type liquid discharge heads, the density of the discharge holes for discharging the droplets formed in the liquid discharge head is increased. There is a need.

Therefore, the liquid discharge head has discharge holes connecting the manifold and the manifold via a plurality of pressurization chambers, respectively, and the plurality of pressurization chambers are arranged in a matrix and opened, and a metal flow path member, A structure in which a piezoelectric actuator substrate having a plurality of displacement elements provided so as to cover each of the pressurizing chambers is laminated is known (see, for example, Patent Document 1). In this liquid ejection head, the pressurizing chambers connected to the plurality of ejection holes are arranged in a matrix, and the displacement elements of the piezoelectric actuator substrate provided so as to cover the chambers are displaced by deformation of the piezoelectric body. Ink is ejected from the ejection holes, and printing is possible at a resolution of 600 dpi in the main scanning direction. Further, the displacement element includes a diaphragm, a common electrode, a piezoelectric ceramic layer, an individual electrode main body at a position facing the pressurizing chamber, and an extraction electrode that is drawn from the individual electrode main body and connected to the external wiring from the flow path member side It has the structure where the individual electrode which consists of was laminated | stacked.

JP 2003-305852 A

However, in the liquid discharge head as described in Patent Document 1, the amount of liquid that can be landed as one pixel on a recording medium by one drive signal from one discharge hole is small, and an image or the like is preferable. In some cases, recording could not be performed.

On the other hand, it is conceivable to form one pixel on a larger recording medium by causing droplets ejected from a plurality of ejection holes to land at close positions on the recording medium. In addition to changing the size of one pixel on the recording medium by changing the size of one pixel on the recording medium by causing droplets discharged from a plurality of discharge holes to land at close positions on the recording medium, The expression can be more extensive. In other words, if it is possible to express four levels of gradation with respect to one pixel by droplets discharged from one discharge hole, if one pixel is formed by droplets discharged from two discharge holes. , 8-level gradation expression is possible. A recording apparatus that forms one pixel on a recording medium using droplets discharged from a plurality of discharge holes in this manner has various advantages.

Also, in order to suppress the crosstalk generated between the pressurizing chambers, it is known that the drive signal for driving the pressurizing unit that pressurizes the liquid in the pressurizing chamber is delayed and sent. However, in the recording apparatus as described above, if the method of giving the delay is not properly controlled, one pixel is formed on the recording medium with droplets ejected from different ejection holes, and good recording can be obtained. There is a risk of not.

Therefore, an object of the present invention is to control to delay a part of the drive signal and send it to the pressurizing unit, and to form one pixel on the recording medium with droplets ejected from a plurality of ejection holes. An object of the present invention is to provide a recording apparatus with high recording accuracy.

The recording apparatus of the present invention includes a plurality of liquid discharge holes, a plurality of liquid pressurizing chambers connected to the plurality of liquid discharge holes, and a plurality of pressurizing units that respectively pressurize the liquid in the plurality of liquid pressurizing chambers. A plurality of liquid discharge holes arranged at equal intervals in a first direction and not arranged in a second direction orthogonal to the first direction. The liquid discharge holes belonging to one liquid discharge hole group are arranged so as to be aligned with the liquid discharge holes belonging to other liquid discharge hole groups, respectively, in the second direction. A liquid discharge head, a transport unit that moves the liquid discharge head relative to the recording medium in the second direction, and a control unit that controls the liquid discharge head and the transport unit, The control unit is arranged to correspond to one liquid pressurizing chamber. When sending the drive signal to the pressurizing unit, the drive signal is sent with a delay so as not to send the drive signal to the pressurizing units corresponding to the two adjacent liquid pressurizing chambers at the same time. When the liquid ejected from the liquid ejection holes aligned in the direction is landed so as to overlap on the recording medium, the liquid pressurizing chamber connected to the liquid ejection holes aligned in the second direction Whether or not to delay the driving signal sent to the corresponding pressurizing unit is made to coincide.

According to the recording apparatus of the present invention, whether or not to delay the drive signal sent to the pressurizing unit corresponding to the pressurizing chamber that ejects the liquid droplets ejected to form one pixel on the recording medium. Therefore, the difference in landing position on the recording medium due to the difference in presence or absence of delay hardly occurs, so that the recording accuracy is improved.

1 is a schematic configuration diagram of a printer that is a recording apparatus according to an embodiment of the present invention. FIG. 2 is a plan view of a flow path member and a piezoelectric actuator substrate that constitute the liquid ejection head of FIG. 1. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. FIG. 5 is a longitudinal sectional view taken along line VV in FIG. 3. FIG. 5 is a schematic diagram illustrating the arrangement of ejection holes according to an embodiment of the present invention and a state in which recording by droplets ejected from the ejection holes proceeds. FIG. 10 is a schematic diagram illustrating the arrangement of ejection holes according to another embodiment of the present invention and the state in which recording by droplets ejected from the ejection holes proceeds. FIG. 3 is a plan view of a flow path member and a piezoelectric actuator substrate constituting a flow path member and a piezoelectric actuator substrate that constitute the liquid ejection head of FIG. 1. FIG. 9 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. FIG. 10 is a longitudinal sectional view taken along line XX in FIG. 9. It is arrangement | positioning of the discharge hole of other embodiment of this invention. FIG.

FIG. 1 is a schematic configuration diagram of a color inkjet printer which is a recording apparatus including a liquid discharge head according to an embodiment of the present invention. This color inkjet printer 1 (hereinafter referred to as printer 1) has four liquid ejection heads 2. These liquid discharge heads 2 are fixed to a carriage 18, and the carriage 18 is in a direction orthogonal to the conveyance direction of the printing paper P that is a recording medium, that is, in a direction from the front to the back in FIG. It is installed so that it can reciprocate. The four liquid ejection heads 2 are arranged along the direction in which the carriage 18 can reciprocate and are fixed to the printer 1. The liquid discharge head 2 has an elongated shape in the conveyance direction of the printing paper P. This long direction is sometimes called the longitudinal direction.

In such a printer 1, by repeating the operation of moving the carriage 18 and performing printing while the printing paper P is stopped, and the operation of transporting the printing paper P without printing, the printing paper P is printed. Can be printed. Printing may be performed in both directions of the reciprocating movement of the carriage 18 or in either direction. If printing is performed in both directions of the reciprocating operation, the number of movements of the carriage 18 can be reduced, so that printing becomes faster.

The recording apparatus of the present invention is not limited to the serial printer as described above, but is a line printer that is fixed to the printer 1 so that the longitudinal direction of the liquid discharge head 2 is directed from the front to the back in FIG. Can also be used.

In the printer 1, a paper feeding unit 114, a transport unit 120, and a paper receiving unit 116 are sequentially provided along the transport path of the printing paper P. In addition, the printer 1 is provided with a control unit 100 for controlling the operation of each unit of the printer 1 such as the liquid discharge head 2 and the paper feeding unit 114.

The paper feed unit 114 includes a paper storage case 115 that can store a plurality of printing papers P, and a paper supply roller 145. The paper feed roller 145 can send out the uppermost print paper P among the print papers P stacked and stored in the paper storage case 115 one by one.

Between the paper feeding unit 114 and the transport unit 120, two pairs of

feed rollers

118a and 118b and 119a and 119b are arranged along the transport path of the printing paper P. The printing paper P sent out from the paper supply unit 114 is guided by these feed rollers and further sent out to the transport unit 120.

The transport unit 120 includes an endless transport belt 111 and two

belt rollers

106 and 107. The conveyor belt 111 is wound around

belt rollers

106 and 107. The conveyor belt 111 is adjusted to a length that allows it to be tensioned with a predetermined tension when it is wound around two belt rollers. Thus, the conveyor belt 111 is stretched without slack along two parallel planes each including a common tangent of the two belt rollers. Of these two planes, the plane closer to the liquid ejection head 2 is a transport surface 127 that transports the printing paper P.

As shown in FIG. 1, a conveyance motor 174 is connected to the belt roller 106. The transport motor 174 can rotate the belt roller 106 in the direction of arrow A. The belt roller 107 can rotate in conjunction with the transport belt 111. Therefore, the conveyance belt 111 moves along the direction of arrow A by driving the conveyance motor 174 and rotating the belt roller 106.

Near the belt roller 107, a nip roller 138 and a nip receiving roller 139 are arranged so as to sandwich the conveyance belt 111. The nip roller 138 is urged downward by a spring (not shown). A nip receiving roller 139 below the nip roller 138 receives the nip roller 138 biased downward via the conveying belt 111. The two nip rollers are rotatably installed and rotate in conjunction with the conveyance belt 111.

The printing paper P sent out from the paper supply unit 114 to the transport unit 120 is sandwiched between the nip roller 138 and the transport belt 111. As a result, the printing paper P is pressed against the transport surface 127 of the transport belt 111 and is fixed on the transport surface 127. The printing paper P is transported in the direction in which the liquid ejection head 2 is installed according to the rotation of the transport belt 111. The outer peripheral surface 113 of the conveyor belt 111 may be treated with adhesive silicon rubber. Thereby, the printing paper P can be securely fixed to the transport surface 127.

The four liquid discharge heads 2 are arranged close to each other along the conveyance direction by the conveyance belt 111. Each liquid discharge head 2 has a liquid discharge head main body 13 at the lower end. A number of ejection holes 8 for ejecting liquid are provided on the lower surface of the liquid ejection head body 13 (see FIGS. 4, 5 and 6).

A droplet (ink) of the same color is ejected from the ejection hole 8 provided in one liquid ejection head 2. Each liquid discharge head 2 is supplied with liquid from an external liquid tank (not shown). The ejection holes 8 of each liquid ejection head 2 are opened in the ejection hole surface, and are in a first direction (a direction parallel to the printing paper P and perpendicular to a second direction in which the carriage 18 reciprocates). Since a plurality of ejection hole groups 7 are formed at equal intervals in the longitudinal direction of the head 2, droplets ejected from one ejection hole group 7 landed at equal intervals in the first direction. A pixel group can be formed, and droplets ejected from the plurality of ejection hole groups 7 land in the vicinity so as to form one pixel on the printing paper P, so that printing can be performed in one direction without a gap. The colors of the liquid ejected from each liquid ejection head 2 are magenta (M), yellow (Y), cyan (C), and black (K), respectively. Each liquid discharge head 2 is arranged with a slight gap between the lower surface of the liquid discharge head main body 13 and the transport surface 127 of the transport belt 111.

Note that printing is performed at an interval of 300 dpi on the forward path of the reciprocating movement of the carriage 18, and printing at a resolution of 600 dpi is performed by printing at an interval of 300 dpi so as to land between 300 dpi pixels printed on the forward path on the return path. May be. In this case, since the pixels adjacent in the first direction are printed in different steps of reciprocation, printing can be performed without being affected by crosstalk, so that the image quality is further improved.

The printing paper P transported by the transport belt 111 passes through the gap between the liquid ejection head 2 and the transport belt 111. At that time, droplets are ejected from the liquid ejection head body 13 constituting the liquid ejection head 2 toward the upper surface of the printing paper P. As a result, a color image based on the image data stored by the control unit 100 is formed on the upper surface of the printing paper P.

A separation plate 140 and two pairs of

feed rollers

121a and 121b and 122a and 122b are disposed between the transport unit 120 and the paper receiving unit 116. The printing paper P on which the color image is printed is conveyed to the peeling plate 140 by the conveying belt 111. At this time, the printing paper P is peeled from the transport surface 127 by the right end of the peeling plate 140. The printing paper P is sent out to the paper receiving unit 116 by the feed rollers 121a to 122b. In this way, the printed printing paper P is sequentially sent to the paper receiving unit 116 and stacked on the paper receiving unit 116.

It should be noted that a paper surface sensor 133 is installed between the liquid ejection head 2 and the nip roller 138 that are on the most upstream side in the conveyance direction of the printing paper P. The paper surface sensor 133 includes a light emitting element and a light receiving element, and can detect the leading end position of the printing paper P on the transport path. The detection result by the paper surface sensor 133 is sent to the control unit 100. The control unit 100 can control the liquid ejection head 2, the conveyance motor 174, and the like so that the conveyance of the printing paper P and the printing of the image are synchronized based on the detection result sent from the paper surface sensor 133.

Next, the liquid discharge head main body 13 constituting the liquid discharge head of the present invention will be described. FIG. 2 is a top view showing the liquid discharge head main body 13. FIG. 3 is an enlarged perspective view of the region surrounded by the one-dot chain line in FIG. 2 and is a part of the liquid discharge head main body 13. FIG. 4 is an enlarged perspective view of the same position as FIG. For ease of understanding in FIGS. 3 and 4, some of the flow paths and the like are omitted, and the end 10 a of the pressurizing chamber 10 is connected to the discharge hole 7. Moreover, although the individual electrode 35 is provided immediately above all the pressurizing chambers 10, since it becomes complicated, only the individual electrode 35 directly above a part of the pressurizing chambers 10 in the lower right of the figure is shown. In FIGS. 3 and 4, in order to make the drawings easy to understand, the pressurizing chamber 10, the squeezing 12 and the discharge hole 8 which are to be drawn by broken lines below the piezoelectric actuator substrate 21 are drawn by solid lines. FIG. 5 is a longitudinal sectional view taken along the line VV in FIG. 4, but the flow paths not belonging to one individual flow path 32 are omitted.

The liquid discharge head body 13 has a flat plate-like channel member 4 and a piezoelectric actuator substrate 21 on the channel member 4. The piezoelectric actuator substrate 21 has a trapezoidal shape, and is disposed on the upper surface of the flow path member 4 so that a pair of parallel opposing sides of the trapezoid is parallel to the longitudinal direction of the flow path member 4. In addition, two piezoelectric actuator substrates 21 are arranged on the flow path member 4 as a whole in a zigzag manner, two along each of the two virtual straight lines parallel to the longitudinal direction of the flow path member 4. Yes. The oblique sides of the piezoelectric actuator substrates 21 adjacent to each other on the flow path member 4 partially overlap in the short direction of the flow path member 4. In the area printed by driving the overlapping piezoelectric actuator unit 21, the droplets ejected by the two piezoelectric actuator substrates 21 are mixed and landed.

The manifold 5 which is a part of the liquid flow path is formed inside the flow path member 4. The manifold 5 has an elongated shape extending along the longitudinal direction of the flow path member 4, and an opening 5 b of the manifold 5 is formed on the upper surface of the flow path member 4. A total of ten openings 5 b are formed along each of two straight lines (imaginary lines) parallel to the longitudinal direction of the flow path member 4. The opening 5b is formed at a position that avoids a region where the four piezoelectric actuator substrates 21 are disposed. The manifold 5 is supplied with liquid from a liquid tank (not shown) through the opening 5b.

The manifold 5 formed in the flow path member 4 is branched into a plurality of pieces (the manifold 5 at the branched portion may be referred to as a sub-manifold 5a). The manifold 5 connected to the opening 5 b extends along the oblique side of the piezoelectric actuator substrate 21 and is disposed so as to intersect with the longitudinal direction of the flow path member 4. In a region sandwiched between two piezoelectric actuator substrates 21, one manifold 5 is shared by the adjacent piezoelectric actuator substrates 21, and the sub-manifold 5 a is branched from both sides of the manifold 5. These sub-manifolds 5 a extend in the longitudinal direction of the liquid discharge head main body 13 adjacent to each other in regions facing the piezoelectric actuator substrates 21 inside the flow path member 4.

The flow path member 4 has four pressure chamber groups 9 in which a plurality of pressure chambers 10 are formed in a matrix (that is, two-dimensionally and regularly). The pressurizing chamber 10 is a hollow region having a substantially rhombic planar shape with rounded corners. The pressurizing chamber 10 is formed so as to open on the upper surface of the flow path member 4. These pressurizing chambers 10 are arranged over almost the entire surface of the upper surface of the flow path member 4 facing the piezoelectric actuator substrate 21. Therefore, each pressurizing chamber group 9 formed by these pressurizing chambers 10 occupies an area having almost the same size and shape as the piezoelectric actuator substrate 21. Further, since the piezoelectric actuator substrate 21 is laminated so as to cover the plurality of pressurizing chambers 10, the opening of each pressurizing chamber 10 is closed by the piezoelectric actuator substrate 21.

In this embodiment, as shown in FIG. 3, the manifold 5 branches into four rows of E1-E4 sub-manifolds 5a arranged in parallel with each other in the short direction of the flow path member 4, and each sub-manifold The pressurizing chambers 10 connected to 5a constitute a row of the pressurizing chambers 10 arranged in the longitudinal direction of the flow path member 4 at equal intervals, and the four rows are arranged in parallel to each other in the lateral direction. Two rows of the pressure chambers 10 connected to the sub-manifold 5a are arranged on both sides of the sub-manifold 5a.

As a whole, the pressurizing chambers 10 connected from the manifold 5 constitute rows of the pressurizing chambers 10 arranged in the longitudinal direction of the flow path member 4 at equal intervals, and the rows are arranged in 16 rows parallel to each other in the short side direction. ing. The number of pressurizing chambers 10 included in each pressurizing chamber row is arranged so as to gradually decrease from the long side toward the short side corresponding to the outer shape of the displacement element 50 that is the pressurizing unit. ing. The discharge holes 8 are also arranged in the same manner. Although this arrangement will be described in detail later, pixels on the printing paper P can be formed by droplets ejected from the two ejection holes 8 and image formation can be performed with a resolution of 300 dpi in the longitudinal direction as a whole. It is possible.

That is, when the discharge hole 8 is projected so as to be orthogonal to the virtual straight line parallel to the longitudinal direction of the flow path member 4, the four sub-manifolds 5a connected to the range of R1 of the virtual straight line shown in FIG. The discharge holes 8, that is, a total of 16 discharge holes 8, are arranged with two discharge holes 8 in the second direction orthogonal to the first direction, and the eight sets of the discharge holes 8 arranged at equal intervals of 300 dpi It has become.

Individual electrodes 35 to be described later are formed at positions facing the pressurizing chambers 10 on the upper surface of the piezoelectric actuator substrate 21. That is, the individual electrode 35 is formed on the upper surface of the piezoelectric actuator substrate 21 in a direction different from the first direction and the first direction. The individual electrode 35 is slightly smaller than the pressurizing chamber 10, has a shape substantially similar to the pressurizing chamber 10, and is disposed so as to be within a region facing the pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 21. ing.

A large number of discharge holes 8 are formed on the lower surface of the flow path member 4. These discharge holes 8 are arranged at positions avoiding the area facing the sub-manifold 5a arranged on the lower surface side of the flow path member 4. Further, these discharge holes 8 are arranged in a region facing the piezoelectric actuator substrate 21 on the lower surface side of the flow path member 4. These discharge hole groups 7 occupy regions of almost the same size and shape as the piezoelectric actuator substrate 21, and droplets are discharged from the discharge holes 8 by displacing the corresponding displacement elements 50 of the piezoelectric actuator substrate 21. it can. The arrangement of the discharge holes 8 will be described in detail later. The discharge holes 8 in each region are arranged at equal intervals along a plurality of straight lines parallel to the longitudinal direction of the flow path member 4.

The flow path member 4 included in the liquid discharge head body 13 has a stacked structure in which a plurality of plates are stacked. These plates are a cavity plate 22, a base plate 23, an aperture (squeezing) plate 24,

supply plates

25 and 26,

manifold plates

27, 28 and 29, a cover plate 30 and a nozzle plate 31 in order from the upper surface of the flow path member 4. is there. A number of holes are formed in these plates. Each plate is aligned and laminated so that these holes communicate with each other to form the individual flow path 32 and the sub-manifold 5a. As shown in FIG. 5, the liquid discharge head body 13 is configured such that the pressurizing chamber 10 is on the upper surface of the flow path member 4, the sub-manifold 5 a is on the inner lower surface side, and the discharge holes 8 are on the lower surface. Each portion constituting the path 32 is disposed close to each other at different positions, and the sub-manifold 5 a and the discharge hole 8 are connected via the pressurizing chamber 10.

孔 The holes formed in each plate will be described. These holes include the following. First, the pressurizing chamber 10 formed in the cavity plate 22. Secondly, there is a communication hole that constitutes a flow path that connects from one end of the pressurizing chamber 10 to the sub-manifold 5a. This communication hole is formed in each plate from the base plate 23 (specifically, the inlet of the pressurizing chamber 10) to the supply plate 25 (specifically, the outlet of the sub-manifold 5a). The communication hole includes the aperture 12 formed in the aperture plate 24 and the individual supply flow path 6 formed in the

supply plates

25 and 26.

Third, there is a communication hole that constitutes a flow path that communicates from the other end of the pressurizing chamber 10 to the discharge hole 8, and this communication hole is referred to as a descender (partial flow path) in the following description. The descender is formed on each plate from the base plate 23 (specifically, the outlet of the pressurizing chamber 10) to the nozzle plate 31 (specifically, the discharge hole 8). Fourthly, there is a communication hole constituting the sub-manifold 5a. The communication holes are formed in the manifold plates 27-29.

Such communication holes are connected to each other to form an individual flow path 32 extending from the liquid inflow port (outlet of the submanifold 5a) to the discharge hole 8 from the submanifold 5a. The liquid supplied to the sub-manifold 5a is discharged from the discharge hole 8 through the following path. First, from the sub-manifold 5a, it passes through the individual supply flow path 6 and reaches one end of the aperture 12. Next, it proceeds horizontally along the extending direction of the aperture 12 and reaches the other end of the aperture 12. From there, it reaches one end of the pressurizing chamber 10 upward. Furthermore, it progresses horizontally along the extending direction of the pressurizing chamber 10 and reaches the other end of the pressurizing chamber 10. While moving little by little in the horizontal direction from there, it proceeds mainly downward and proceeds to the discharge hole 8 opened in the lower surface.

The piezoelectric actuator substrate 21 has a laminated structure composed of two piezoelectric

ceramic layers

21a and 21b, as shown in FIG. Each of these piezoelectric

ceramic layers

21a and 21b has a thickness of about 20 μm. The thickness of the laminated body of the piezoelectric

ceramic layers

21a and 21b of the piezoelectric actuator substrate 21 is about 40 μm, and the displacement can be increased by being 100 μm or less. The piezoelectric actuator substrate 21 is laminated on the planar surface of the flow path member 4 where the pressurizing chamber 10 is open, and the piezoelectric

ceramic layers

21 a and 21 b straddle the plurality of pressurizing chambers 10. (See FIG. 3). The piezoelectric

ceramic layers

21a and 21b are made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity.

In the recording apparatus using the liquid discharge head 2 in which the piezoelectric actuator substrates 21 are stacked so as to cover the plurality of pressurizing chambers 10 as described above, the piezoelectric actuator substrate is provided between two adjacent pressurizing chambers 10. 21. It is effective by a recording device that delays the drive signal so as to suppress crosstalk when crosstalk occurs through the apparatus 21, but it is effective even if the liquid in the pressurizing chamber 10 is pressurized by other methods. There is. In addition, the adjacent pressurization chamber 10 said here is the pressurization chamber 10 with the shortest distance between them, More specifically, it is a substantially rhombus (more generally a substantially parallelogram-shaped). It is the pressurization chamber 10 which a side opposes and adjoins.

The piezoelectric actuator substrate 21 is made of a common electrode 34 made of a metal material such as Ag—Pd, an individual electrode 35 made of a metal material such as Au, and a metal material such as Au made on the individual electrode 35. It has a connection electrode. The individual electrode 35 is, as described above, the individual electrode main body disposed at a position facing the pressurizing chamber 10 on the upper surface of the piezoelectric actuator substrate 21, and the lead extracted from the individual electrode main body to a position where the pressurizing chamber 10 is not present. Electrodes. A connection electrode 36 is formed at a position where there is no pressurizing chamber 10 of the extraction electrode. The thickness of the individual electrode 35 is 0.3 to 1 μm. The connection electrode 36 is made of, for example, gold containing glass frit, and has a convex shape with a thickness of about 5 to 15 μm. The connection electrode 36 is electrically joined to an electrode provided on an FPC (FlexibleFlexPrinted Circuit) which is an external wiring (not shown). Although details will be described later, a drive signal (drive voltage) is supplied to the individual electrode 35 from the control unit 100 through the FPC. The drive signal is supplied in a constant cycle in synchronization with the conveyance speed of the printing paper P.

The common electrode 34 is formed over almost the entire surface in the area between the piezoelectric ceramic layer 21a and the piezoelectric ceramic layer 21b. That is, the common electrode 34 extends so as to cover all the pressurizing chambers 10 in the region facing the piezoelectric actuator substrate 21. The thickness of the common electrode 34 is about 2 μm. The common electrode 34 is grounded in a region not shown, and is held at the ground potential. In the present embodiment, a surface electrode (not shown) different from the individual electrode 35 is formed on the piezoelectric ceramic layer 21b at a position avoiding the electrode group composed of the individual electrodes 35. The surface electrode is electrically connected to the common electrode 34 through a through-hole formed in the piezoelectric ceramic layer 21b, and is connected to another electrode in the external wiring, like the large number of individual electrodes 35. Has been.

The above is the structure in the case where the piezoelectric actuator substrate 21 has two piezoelectric ceramic layers. However, the piezoelectric ceramic layers having three or more phases are laminated so that the individual electrodes 35 and the common electrodes 34 are alternately arranged. You may arrange.

As shown in FIG. 5, the common electrode 34 and the individual electrode 35 are arranged so as to sandwich only the uppermost piezoelectric ceramic layer 21b. A region sandwiched between the individual electrode 35 and the common electrode 34 in the piezoelectric ceramic layer 21b is called an active portion, and the piezoelectric ceramic in that portion is polarized in the thickness direction. In the piezoelectric actuator substrate 21 of the present embodiment, only the uppermost piezoelectric ceramic layer 21b includes an active portion, and the piezoelectric ceramic 21a does not include an active portion and functions as a diaphragm. The piezoelectric actuator substrate 21 has a so-called unimorph type configuration.

As will be described later, when a predetermined drive signal is selectively supplied to the individual electrode 35, pressure is applied to the liquid in the pressurizing chamber 10 corresponding to the individual electrode 35. As a result, droplets are discharged from the corresponding liquid discharge ports 8 through the individual flow paths 32. That is, the portion of the piezoelectric actuator substrate 21 that faces each pressurizing chamber 10 corresponds to the individual displacement element 50 corresponding to each pressurizing chamber 10 and the liquid discharge port 8. That is, in the laminate composed of two piezoelectric ceramic layers, the displacement element 50 having a unit structure as shown in FIG. 5 is positioned immediately above the pressurizing chamber 10 for each pressurizing chamber 10. The diaphragm 21a, the common electrode 34, the piezoelectric ceramic layer 21b, and the individual electrode 35 are formed. The piezoelectric actuator substrate 21 includes a plurality of displacement elements 50. In this embodiment, the amount of liquid ejected from the liquid ejection port 8 by one ejection operation is about 5 to 7 pL (picoliter).

In an actual driving procedure in the present embodiment, the individual electrode 35 is set to a potential higher than the common electrode 34 (hereinafter referred to as a high potential) in advance, and the individual electrode 35 is temporarily set to the same potential as the common electrode 34 every time there is a discharge request. (Hereinafter referred to as a low potential), and then set to a high potential again at a predetermined timing. As a result, the piezoelectric

ceramic layers

21a and 21b return to their original shapes at the timing when the individual electrodes 35 become low potential, and the volume of the pressurizing chamber 10 increases compared to the initial state (the state where the potentials of both electrodes are different). To do. At this time, a negative pressure is applied to the pressurizing chamber 10 and the liquid is sucked into the pressurizing chamber 10 from the manifold 5 side. Thereafter, at the timing when the individual electrode 35 is set to a high potential again, the piezoelectric

ceramic layers

21a and 21b are deformed so as to protrude toward the pressurizing chamber 10, and the pressure in the pressurizing chamber 10 is reduced due to the volume reduction of the pressurizing chamber 10. The pressure becomes positive and the pressure on the liquid rises, and droplets are ejected. That is, a drive signal including a pulse based on a high potential is supplied to the individual electrode 35 in order to eject a droplet. This pulse width is ideally AL (Acoustic Length), which is the length of time during which the pressure wave propagates from the manifold 5 to the discharge hole 8 in the pressurizing chamber 10. According to this, when the inside of the pressurizing chamber 10 is reversed from the negative pressure state to the positive pressure state, both pressures are combined, and the liquid droplets can be discharged at a stronger pressure.

If this is done, crosstalk may occur. The main crosstalk is that when the pressure displacement element 50 is displaced, the displacement element 50 contracts, so that the stress affects the adjacent displacement element, and the vibration of the liquid in the pressurizing chamber 10 is a flow path. What is transmitted to the adjacent pressurizing chamber 10 through the member 4, and vibrations of the liquid in the pressurizing chamber 10 are transmitted to the sub manifold 5a through the squeezing 12, and further transmitted to the pressurizing chamber 10 connected to the sub manifold 5a. There is. In order to suppress such crosstalk, it is conceivable to delay the drive signal and send it to the displacement element 50. For example, a drive signal is sent at a time (T + delay time) when a drive signal is originally sent at a certain time T, and two adjacent pressurizing chambers 10 arranged in a matrix form are used. By not sending drive signals to the displacement element 50 facing the chamber at the same time, it is effective in suppressing the first two crosstalks among the main crosstalks described above.

More specific explanation will be given with reference to FIG. FIG. 6 shows a part of the arrangement of the ejection holes 8 shown in FIG. 4 and shows the progress of recording performed by the ejection holes 8 in the range of R1. The discharge holes 8 constitute a discharge hole group 7 that is arranged two-dimensionally at equal intervals d in the first direction and so as not to line up in the second direction orthogonal to the first direction. The discharge holes 8 belonging to the discharge hole group 7 are aligned with the discharge holes belonging to the other discharge hole groups 7 (discharge holes 8 not included in the discharge hole group 7 in FIG. 6) in the second direction. Has been placed. Thus, printing can be performed on the printing paper P at intervals d by the ejection holes 8 belonging to the ejection hole group 7, and 1 on the printing paper P can be obtained by droplets ejected from the two ejection hole groups 7. Pixels can be formed. The recording progress state shows a state in which one line is printed by the ejection holes 8 within the range of R1. When the printing paper P moves relative to the liquid ejection head 2 and reaches a predetermined position, droplets are ejected from the ejection hole array N1 to form pixels. Thereafter, droplets are sequentially discharged from the discharge holes N2 to N16. The droplets ejected from the ejection hole array N8 land on the printing paper P in the vicinity of the pixels formed by the ejection hole array N1 (ideally at the same point) and combine to form one pixel. In the same manner, one line in which one pixel is formed by droplets ejected from the two ejection holes 8 can be printed. Note that, depending on the object to be printed, one pixel is formed by droplets ejected from one ejection hole 8.

More specifically, the discharge holes 8 included in the discharge hole group 7 constitute discharge hole rows parallel to the first direction of eight rows N1 to N7 and N9, and the discharge holes of each discharge hole row. 8 are arranged at equal intervals 8d. The discharge holes 8 included in one discharge hole array (for example, the discharge hole array N1) are connected to the pressurization chambers 10 included in one pressurization chamber array (for example, the pressurization chamber array C1). . The pressurizing chamber row does not necessarily have to be parallel to the first direction, but if it is parallel to the first direction, the symmetry of the structure of the flow path is increased and irregular vibrations are unlikely to occur. Although the pressurizing chamber rows are C1 to C16 and the liquid supply and discharge rows are N1 to N16 in order in the second direction, the pressurizing chambers are arranged by the arrangement shown in FIGS. Row C4 corresponds to discharge hole N5, pressurization chamber row C5 corresponds to discharge hole N4, pressurization chamber row C8 corresponds to discharge hole N9, and pressurization chamber row C9 corresponds to discharge hole N8. The pressure chamber row C12 corresponds to the discharge hole N13, and the pressurization chamber row C13 corresponds to the discharge hole N12. By adopting such a structure, the pressurizing chambers 10 can be densely arranged in a matrix, and the overall size can be reduced.

A drive signal is sent simultaneously to a single pressurizing chamber row (actually a change in voltage corresponds to the discharge hole from which the droplet is discharged, but it also includes sending a signal whose voltage does not change) In the following description, the same may be expressed in the following), and the presence or absence of delay is different between two adjacent pressurizing chamber rows. Specifically, since one pressurizing chamber 10 has four pressurizing chambers 10 adjacent to each other, there are four sets of pressurizing chambers 10 adjacent to the one pressurizing chamber 10. There will be. In any of the four sets of two pressurizing chambers 10, the presence or absence of delay of the two pressurizing chambers 10 is changed. Thereby, it is possible to prevent the drive signals from being simultaneously sent to the adjacent pressurizing chambers 10 and to suppress crosstalk. 4 to 6, the delays of the pressurization chamber rows C1, C3, C5, C7, C9, C11, C13, and C15 are sent with a delay 0, that is, a non-delayed drive signal, and the pressurization chamber rows C2, C4, C6, C8, C10, C12, C14, and C16 are sent with a drive signal having a delay 1, that is, a predetermined delay time. In order to reduce crosstalk, three types of delay times can be set, and the pressure chambers connected to one sub-manifold 5a include different delay times including those that are not delayed. You can do it.

However, there may be a slight difference in the liquid ejection characteristics depending on the presence or absence of delay. Since the displacement element 50 given the delay is driven after the displacement element 50 not given the delay, it is affected even though the influence is small as compared with the case of being driven simultaneously. For example, if the discharge speed of the liquid droplets discharged by the displacement element 50 with a delay is slightly lowered, the landing position on the printing paper P is shifted. The deviation of the landing position is not good even in normal printing, but when one pixel on the printing paper P is formed by droplets ejected from the plurality of ejection holes 8, one pixel has an extremely elliptical shape. It must be less so that it does not become separated and is not recognized as one pixel. When one pixel is formed by droplets ejected from the plurality of ejection holes 8, the presence or absence of delay sent to the displacement elements 50 corresponding to the ejection holes 8 is made the same, that is, all the displacement elements By either sending a non-delayed drive signal to 50 or sending a delayed drive signal to all the displacement elements 50, it is possible to increase the formation accuracy of one pixel and consequently the recording accuracy. .

Note that this is because, as described above, the difference in ejection characteristics is caused by the difference in the presence or absence of delay, but the difference in ejection characteristics is also caused to some extent by the length of the delay time. For this reason, when two or more types of delay times can be set, when one pixel is formed by droplets ejected from the plurality of ejection holes 8, it is sent to the displacement element 50 corresponding to those ejection holes 8. The recording accuracy is higher when the delay time (including the case where there is no delay) is the same. That is, for example, when the delay times are T1 seconds (= 0 seconds), T2 seconds, and T3 seconds, the drive signals sent to the displacement element 50 corresponding to the ejection holes 8 that form one pixel all have T1 time. Or all T2 or all T3.

When forming one pixel with a plurality of droplets, the pixel size may change due to the difference in droplet landing time. For example, a difference may occur depending on whether the previously landed liquid has landed on the printing paper P or has landed in the middle. The degree of influence and which pixel becomes larger vary depending on the type of recording paper P and the like, but if the landing time intervals are set to the same level, the degree of influence can be reduced.

4 to 6 makes it possible to reduce the difference in the landing time interval of the droplets forming one pixel. That is, one pixel is formed by droplets ejected from the first and ninth pressure chamber rows in the second direction, and the combination of the second row and the tenth row to the eighth row and the 16th row below. By combining with eyes, the difference in landing time interval can be reduced. More generally speaking, there are n rows (n is an even number of 4 or more) of ejection hole rows in one ejection hole group, and there are m (m is an integer of 2 or more) ejection hole groups. Then, when the pressurization chamber row having n × m rows is expressed as the 1st to m × n pressurization chamber rows in the second direction in order, the kth row (k is an integer from 1 to n) The liquid discharge holes connected to the liquid pressurizing chambers belonging to at least two of the liquid pressurizing chamber rows among the liquid pressurizing chamber rows up to k + n × (m−1) rows every n−1 rows. May be arranged in the second direction. Since the above-mentioned influence becomes large when n is 3 or more, such an arrangement is particularly useful when n is 3 or more.

Even in the different piezoelectric actuator substrates 21, if the pressurizing chamber rows are the first to m × n pressurizing chamber rows in the second direction and the same arrangement and driving are performed, the different piezoelectric actuator substrates 21 are arranged. Similarly, the recording accuracy can be increased for pixels that are printed across the boundary.

Further, in consideration of the influence of the liquid discharge head 2 on the recording due to the poor fixed position accuracy (angle accuracy) and the poor production accuracy of the liquid discharge head 2, the liquid droplets forming one pixel are discharged. The recording accuracy can be improved if the hole 8 is positioned as close as possible on the liquid ejection head 2.

FIG. 7 shows an example of the arrangement of the ejection holes 208 in another embodiment of the recording apparatus of the present invention and the progress of recording performed by the ejection holes 208 within the range of R2. This recording apparatus is the same as the recording apparatus shown in FIGS. 1 to 5 except for the arrangement of the discharge holes 208. In FIG. 7, the discharge holes 208 constitute a discharge hole group 207 that is two-dimensionally arranged so as not to line up in a second direction that is equally spaced d in the first direction and orthogonal to the first direction. is doing. In FIG. 7, one pixel is formed by droplets ejected from the first and third pressurizing chamber rows in the second direction, and the second, fourth, fifth, and seventh rows are hereinafter referred to. By combining the 14th and 16th columns, the positions of the ejection holes 8 forming one pixel on the ejection hole liquid ejection head 2 can be made closer. More generally speaking, there are n rows (n is an even number of 4 or more) of ejection hole rows in one ejection hole group, and m (m is an integer of 2 or more) ejection hole groups. In the apparatus, when the pressurization chamber row having n × m rows is expressed as the 1st to m × n pressurization chamber rows in the second direction in order, the m × i + 1th row (i is any of 0 to n−1). The liquid discharge holes connected to the liquid pressurizing chambers belonging to at least two liquid pressurizing chamber rows among the liquid pressurizing chamber rows from the m × i + m-th row to the second direction. You should just make it line up. Since the above-mentioned influence becomes large when n is 3 or more, such an arrangement is particularly useful when n is 3 or more.

In the recording apparatus as described above, the printing may be performed when the relative movement between the liquid discharge head 2 and the printing paper P is moved in one direction parallel to the second direction, or the reciprocating movement. It can be done in both directions. Even when printing is performed by reciprocal movement, the recording accuracy can be increased by the same delay of the driving signal as described above.

Note that when a delay is applied to the drive signal, the landing position on the recording paper P is shifted by the delay. In order to correct this, the ejection hole arrays may be shifted in advance in the second direction. However, when reciprocal printing is performed in this case, there is a difference in landing position between the pixel with delay and the pixel without delay in the forward path and the backward path. Therefore, the delay time given when recording in the forward path is T1 seconds (= 0 second), T2 seconds... Tp seconds (p is an integer of 2 or more) in order from the shortest time including the case where no delay is made. In this case, in the forward path, the driving which gives a delay time of (Tp−Tq) seconds to the pressurizing chamber which sends a drive signal giving a delay time of Tq (q is an integer of 1 to p) is given in the return path. By sending a signal, it is preferable because the position of the ejection hole 8 shifted in advance is corrected in a direction that cancels out.

Furthermore, by changing the arrangement of the discharge holes 8, when projected onto a straight line parallel to the first direction, the displacement element 50 corresponding to the pressurizing chamber 10 connected to the adjacent discharge hole 8 on the straight line, By sending drive signals so that the presence or absence of delay is different, the image quality can be further improved. Depending on the presence or absence of a delay, a difference may occur in the landing position or the size of the pixel, but the boundary may be conspicuous when a pixel with a delay is continuous and a pixel without a delay is adjacent to the pixel. By doing the above, since there is no continuation of pixels with delay and pixels without delay in the first direction on the printing paper P, the appearance of the recording state is improved. When there are a plurality of delay times given to the drive signal, pixels in the first direction are arranged in the first direction so that pixels having the same delay time (including those having no delay time) are not arranged in the first direction on the printing paper P. What is necessary is just to send the drive signal which gave the delay by different delay time to the displacement element 50 corresponding to the pressurization chamber 10 connected to the discharge hole 8 adjacent on this straight line when it projects on a parallel straight line.

Furthermore, if the ejection holes 8 that give the delay time are changed depending on the time so that pixels of the same delay time (including those without delay time) are not arranged in the first direction on the printing paper P, the first Since the printing state in the direction and the printing state in the second direction are close to each other, the appearance of the recording state is improved.

In this embodiment, the displacement element 50 using piezoelectric deformation is shown as the pressurizing unit. However, the present invention is not limited to this, and any other device that can pressurize the liquid in the liquid pressurizing chamber 10 is used. For example, the liquid in the liquid pressurizing chamber 10 may be heated and boiled to generate pressure, or may be one using MEMS (Micro Electro Mechanical Systems).

Subsequently, another liquid discharge head that can be used in the recording apparatus of the present invention will be described. FIG. 8 is a plan view of the head main body 302a. FIG. 9 is an enlarged view of the region surrounded by the alternate long and short dash line in FIG. 8, and a part of the flow paths is omitted for explanation. In FIG. 9, in order to make the drawing easy to understand, the manifold 305, the discharge hole 308, and the pressurizing chamber 310 that are to be drawn by broken lines below the piezoelectric actuator substrate 321 are drawn by solid lines. Moreover, although the individual electrode 325 is provided immediately above all the pressurizing chambers 310, since it becomes complicated, only the individual electrode 325 directly above the partial pressurizing chamber 310 in the lower right of the figure is shown. FIG. 10 is a longitudinal sectional view taken along line XX in FIG.

The head main body 302a of this embodiment includes a flow path member 304 and a piezoelectric actuator substrate 321 in which a displacement element (pressurizing unit) 330 is formed.

The flow path member 304 constituting the head main body 302a includes a manifold 305, a plurality of pressure chambers 310 connected to the manifold 305, and a plurality of discharge holes 308 respectively connected to the plurality of pressure chambers 310. The pressurizing chamber 310 is open on the upper surface of the flow path member 304. An upper surface of the flow path member 304 has an opening 305a connected to the manifold 305, and liquid is supplied from the opening 305a.

Further, a piezoelectric actuator substrate 321 including a displacement element 330 is bonded to the upper surface of the flow path member 304, and each displacement element 330 is provided on the pressurizing chamber 310.

The head main body 302 a has a flat plate-like flow path member 304 and one piezoelectric actuator substrate 321 including a displacement element 330 on the flow path member 304. The planar shape of the piezoelectric actuator substrate 321 is rectangular, and is arranged on the upper surface of the flow path member 304 so that the long side of the rectangle is along the longitudinal direction of the flow path member 304.

Four manifolds 305 are formed inside the flow path member 304. The manifold 305 has an elongated shape extending along the longitudinal direction of the flow path member 304, and openings 305 a of the manifold 305 are formed on the upper surface of the flow path member 304 at both ends thereof. In this embodiment, four manifolds 305 are provided independently, and a liquid is supplied from the outside to each opening 305a.

The flow path member 304 is formed by two-dimensionally expanding a plurality of pressurizing chambers 310. The pressurizing chamber 310 is a hollow region having a substantially rhombic planar shape with rounded corners. The pressurizing chamber 310 is connected to one manifold 305 through an individual supply channel 314. Along with one manifold 305, there are four pressurization chamber rows 311, which are rows of pressurization chambers 310 connected to the manifold 305, two on each side of the manifold 305. Therefore, a total of 16 pressurizing chamber rows 311 are provided. The intervals in the longitudinal direction of the pressurizing chambers 310 in the respective pressurizing chamber rows 311 are the same, and the interval is 37.5 dpi. Note that the pressurizing chamber 310 at the end of each pressurizing chamber row 311 is a dummy and is not connected to the manifold 305. By this dummy, the structure (rigidity) around the pressurizing chamber 310 one inner side from the end is close to the structure (rigidity) of the other pressurizing chamber 310, so that the difference in liquid ejection characteristics can be reduced.

The pressurizing chambers 310 of each pressurizing chamber row 311 are arranged in a staggered manner so that the corners are located between the adjacent pressure chamber rows 11. Of the 16 pressurizing chamber rows 311, the eight rows of pressurizing chambers 310 on one side from the center in the short side direction are arranged slightly shifted in the longitudinal direction, so that the entire 8 rows are 300 dpi in the longitudinal direction. They are lined up at intervals. The same applies to the eight rows on the opposite side from the center, and the arrangement of the pressurizing chambers 310 is such that they are translated in the lateral direction. These pressurizing chambers 310 are arranged over almost the entire surface of the upper surface of the flow path member 304 in the region facing the piezoelectric actuator substrate 321, although there are some widened portions such as between the pressurizing chamber groups. . That is, the pressurizing chamber group formed by these pressurizing chambers 310 occupies a region having substantially the same size and shape as the piezoelectric actuator substrate 321. Further, the opening of each pressurizing chamber 310 is closed by bonding the piezoelectric actuator substrate 321 to the upper surface of the flow path member 304.

A descender connected to the discharge hole 308 opened in the discharge surface on the lower surface of the flow path member 304 extends from the corner facing the corner where the individual supply flow path 314 of the pressurizing chamber 310 is connected. The descender extends in the direction of extending the diagonal line of the pressurizing chamber in plan view. That is, the arrangement of the discharge holes 308 in the longitudinal direction and the arrangement of the pressurizing chambers 310 are the same. In each pressurization chamber row 311, the pressurization chambers 310 are arranged at an interval of 37.5 dpi, and the discharge holes 308 connected to the two manifolds 305 on one side from the center in the short side direction as a whole are arranged in the longitudinal direction (first order). 1 direction) at an interval of 300 dpi. The ejection holes 308 on both sides with respect to the center in the short direction are in a relationship of being translated in a second direction (short direction) which is a direction orthogonal to the first direction, and one side The discharge hole 308 is aligned with the discharge hole 308 on the other side in the second direction.

In other words, when the discharge holes 308 are projected so as to be orthogonal to the virtual straight line parallel to the longitudinal direction of the flow path member 304, each manifold 305 is within the range of R4 of the virtual straight line shown in FIG. That is, four discharge holes 308 connected to each other, that is, a total of 16 discharge holes 308 are projected at the same position two by two, and the projected points are equally spaced at 300 dpi. Thus, by supplying the same color ink to all the manifolds 305, it is possible to form an image with a resolution of 300 dpi in the longitudinal direction with the liquid ejected from the two ejection holes 308 as a whole.

Individual electrodes 325 are formed at positions facing the pressurizing chambers 310 on the upper surface of the piezoelectric actuator substrate 321. The individual electrode 325 includes an individual electrode main body 325a that is slightly smaller than the pressurizing chamber 310 and has a shape substantially similar to the pressurizing chamber 310, and an extraction electrode 325b that is extracted from the individual electrode main body 325a. In the same manner as the pressurizing chamber 310, the individual electrode 325 constitutes an individual electrode row. A common electrode surface electrode 328 that is electrically connected to the common electrode 324 is formed on the upper surface of the piezoelectric actuator substrate 321. The common electrode surface electrodes 328 are formed in two rows along the longitudinal direction at the central portion in the short direction of the piezoelectric actuator substrate 321 and are formed in one row along the short direction near the end in the longitudinal direction. ing. Although the illustrated common electrode surface electrode 328 is intermittently formed on a straight line, it may be formed continuously on a straight line. Two signal transmission units are arranged and bonded to the piezoelectric actuator substrate 321 from the two long sides of the piezoelectric actuator substrate 321 toward the center. The common electrode surface electrode 328 is connected at the end of the signal transmission unit (the front end and the longitudinal end of the piezoelectric actuator substrate 321), and the common electrode surface electrode 328 and the common electrode connection electrode formed thereon are provided. Since the area is larger than that of the extraction electrode 325b and the connection electrode 326 formed on the extraction electrode 325b, the signal transmission portion can be hardly separated from the end.

Further, the discharge hole 308 is disposed at a position avoiding a region facing the manifold 305 disposed on the lower surface side of the flow path member 304. Further, the discharge hole 308 is disposed in a region facing the piezoelectric actuator substrate 321 on the lower surface side of the flow path member 304. These discharge holes 308 occupy a region having substantially the same size and shape as the piezoelectric actuator substrate 321 as one group, and the displacement elements 330 of the corresponding piezoelectric actuator substrate 321 are displaced from the discharge holes 308. Droplets can be ejected.

The flow path member 304 included in the head main body 302a has a laminated structure in which a plurality of plates are laminated. These plates are, in order from the upper surface of the flow path member 304, a cavity plate 304a, a base plate 304b, an aperture plate 304c, a supply plate 304d, manifold plates 304e-g, a cover plate 304h, a cover space plate 304i, and a nozzle plate 304j. It is. The basic flow path configuration is the same as that shown in FIG. In the cover space plate 304i, a hole serving as a damper chamber 318 formed under the manifold 305 is formed. The damper chamber 318 is not connected to the liquid flow path and does not allow liquid to enter. The cover plate 304h between the damper chamber 318 and the manifold 305 serves as a damper. By changing the volume of the manifold 305, excess or deficiency of the liquid supply of the manifold 305 makes it difficult to affect the discharge, or the manifold 305 The pressure is transmitted between the pressurizing chambers 310 to reduce the crosstalk that affects the discharge characteristics. Even if the damper chamber 318 is a sealed space, the damper is activated by the volume change of the air. However, if the damper chamber 318 is connected to the outside of the flow path member 304 by a hole different from the above-described hole. Work better as a damper.

The basic structure of the piezoelectric actuator substrate 321 is the same as that of the piezoelectric actuator substrate 21 shown in FIG.

In FIG. 9, the pressurizing chamber row 311 is C301 to C316 in order from the left, and the discharge hole rows are N301 to N316 in order. The pressurizing chamber 310 of C301 is connected to the discharge hole 8 of N301, which is the same up to C316 and N316, and the order is not changed. As shown in FIG. 11, the discharge holes 308 included in the discharge hole group 307 constitute discharge hole arrays 308 parallel to the first direction of eight lines N301 to N308, and the discharge holes 308 of each discharge hole array. Are arranged at equal intervals 8d, and the discharge holes 308 are aligned at equal intervals d as a whole. The discharge holes 308 that do not belong to the discharge hole group 307 constitute another discharge hole group. The arrangement of the discharge rows N309 to N316 constituting this discharge hole group is an arrangement in which the discharge hole rows N301 to N308 are translated in the second direction.

The pressurization chamber rows C301, C303, C305, C307, C309, C311, C313, and C315 are sent with a delay 0, that is, a non-delayed drive signal, and the pressurization chamber rows C302, C304, C306, C308, C310, C312 and C314 , C316 is sent with a delay 1, that is, a drive signal with a predetermined delay time. As a result, when the droplets ejected from the ejection holes 308 aligned in the second direction land on the vicinity of the recording medium P to form one pixel, the liquid ejected by the delayed drive signal Since it is a combination of droplets and droplets ejected with an undelayed drive signal, printing variations can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Printer 2 ... Liquid discharge head 4 ... Channel member 5 ... Manifold 5a ... Sub-manifold 5b ... Opening 8 ... Discharge hole 9 ... Pressurization chamber group 10 ... Pressurizing chamber 12 ... Squeezing 13 ... Head body 21 ... Piezoelectric actuator substrate 21a ... Piezoelectric ceramic layer (vibrating plate)
21b: Piezoelectric ceramic layer 22-31: Plate 32 ... Individual flow path 34 ... Common electrode 35 ... Individual electrode 36 ... Connection electrode 50 ... Displacement element

Claims

A plurality of liquid discharge holes, a plurality of liquid pressurization chambers connected to the plurality of liquid discharge holes, respectively, and a plurality of pressurization units that pressurize the liquid in the plurality of liquid pressurization chambers, respectively. The plurality of liquid discharge holes constitute a plurality of liquid discharge hole groups arranged at equal intervals in the first direction and not arranged in a second direction orthogonal to the first direction, The liquid discharge holes belonging to one liquid discharge hole group, the liquid discharge holes belonging to the other liquid discharge hole group, and the liquid discharge heads arranged to be aligned in the second direction, respectively,
A transport unit that moves the liquid ejection head relative to the recording medium in the second direction;
A controller that controls the liquid discharge head and the transport unit;
When the control unit sends a drive signal to the pressurization unit corresponding to one liquid pressurization chamber, the control unit does not simultaneously send the drive signal to the pressurization unit corresponding to two adjacent liquid pressurization chambers. As described above, when the drive signal is sent with a delay and the liquid ejected from the liquid ejection holes aligned in the second direction is landed on the recording medium so as to overlap, it is aligned in the second direction. The recording apparatus according to claim 1, wherein whether or not the drive signal to be sent to the pressurizing unit corresponding to the liquid pressurizing chamber connected to the liquid discharge hole is delayed is matched.
Each of the plurality of liquid ejection hole groups includes n rows (n is an integer of 2 or more) of liquid ejection holes in which the plurality of liquid ejection holes are arranged in the first direction. The plurality of liquid pressurization chambers respectively connected to the plurality of liquid discharge holes belonging to the group are each composed of n columns of liquid pressurization chamber rows, and the plurality of the liquid pressurization chambers included in one liquid discharge hole row The liquid discharge hole is connected to each of the plurality of liquid pressurization chambers included in one liquid pressurization chamber row, and the control unit corresponds to the pressurization corresponding to one liquid pressurization chamber row. The recording apparatus according to claim 1, wherein a driving signal to be sent to the unit is sent simultaneously.
n is an even number of 4 or more, the number of the liquid ejection hole groups is m (m is an integer of 2 or more), and the liquid pressurizing chamber rows in the 1st to m × nth rows are sequentially arranged in the second direction. When expressed as a liquid pressurization chamber row, at least two liquid pressurization chambers in the liquid pressurization chamber row from the m × i + 1th row (i is an integer from 0 to n−1) to the m × i + mth row. The recording apparatus according to claim 2, wherein the liquid discharge holes connected to the liquid pressurizing chambers belonging to a pressure chamber row are arranged side by side in the second direction.
n is an even number of 4 or more, the number of the liquid ejection hole groups is m (m is an integer of 2 or more), and the liquid pressurizing chamber rows in the 1st to m × nth rows are sequentially arranged in the second direction. When expressed as a liquid pressurization chamber row, of the liquid pressurization chamber rows from the k-th row (k is an integer of any of 1 to n) to every n-1 row to the k + n × (m-1) -th row 3. The liquid ejection holes connected to the liquid pressurizing chambers belonging to at least two rows of the liquid pressurizing chambers are arranged in the second direction, respectively. Recording device.
n is 3 or more, and the control unit sends a drive signal with a delay time of any one of 2 to n-1 types, and sends two adjacent liquid pressurizations. The pressurizing unit corresponding to the chamber is sent with a delay with different delay times, and a drive signal is sent so that the liquid ejected from the liquid ejection holes arranged in the second direction overlaps on the recording medium. When performing the same, the delay time when delaying the drive signal sent to the pressurizing unit corresponding to the liquid pressurizing chamber connected to the liquid ejection holes arranged in the second direction is made the same. The recording apparatus according to claim 2.
When the control unit projects the liquid discharge hole onto a straight line parallel to the first direction, the control unit applies the pressurization unit corresponding to the liquid pressurization chamber connected to the liquid discharge hole adjacent on the straight line. The recording according to any one of claims 1 to 5, wherein the presence or absence of a delay is different, and when there are a plurality of types of delay time given to the drive signal, a drive signal given a delay with different delay times is sent. apparatus.
The control unit causes the liquid ejection head to reciprocate relative to the recording medium along the second direction, and causes the recording to be performed at any time of reciprocation. 7. The recording apparatus according to any one of items 6 to 6.
The control unit sets the delay time to be given when recording on the forward path in order from the shortest time including the case of not delaying, T1 second (= 0 second), T2 second... Tp second (p is 2 or more) Drive signal giving a delay time of (Tp−Tq) seconds in the return path to the pressurizing unit that sends a drive signal giving a delay time of Tq (q is an integer of 1 to p) in the forward path The recording apparatus according to claim 7, wherein: