JP4713069B2 - Inkjet printer head - Google Patents

Description

The present invention relates to an ink jet printer heads of the piezoelectric type or the like.

  In an on-demand type piezoelectric ink jet printer head of the prior art, an ink jet head unit (hereinafter simply referred to as a head unit) in which nozzle rows are arranged in a direction perpendicular to the printing direction includes a plurality of nozzles and each nozzle. And a cavity unit having a common ink chamber (manifold chamber) for supplying ink to the plurality of pressure chambers, and a drive unit for each of the pressure chambers provided on the back side of the cavity unit. And a flexible flat cable that transmits an electrical signal to the piezoelectric actuator.

As a configuration for fixing the head unit to a member located on the back side thereof, for example, Patent Document 1 describes a configuration in which the head unit is fixed to the bottom plate of the head holder and a protective cover is placed on the front surface of the head unit. ing. In this Patent Document 1, a technique is shown in which, in the bottom plate of the head holder, an adhesive pouring hole is formed at positions where the vicinity of the four corners of the back surface of the head unit and a part of the back surface of the protective cover can be exposed. At locations where the head units are arranged side by side, an adhesive pouring hole is formed so that a portion straddling the back surface of the adjacent head units is exposed. Then, the adhesive is poured into the adhesive pouring hole in a state where the head unit is disposed on the front side of the bottom plate and the protective cover is put on. As a result, the adhesive comes into contact with the vicinity of the four corners of the back surface of the head unit and the back surface of the protective cover and cures, and the head unit and the protective cover are fixed to the bottom plate.
Japanese Patent Laid-Open No. 2002-066731 (see FIGS. 7 and 9)

Conventionally, the head unit is directly bonded and fixed to the bottom plate of the head holder. However, since the head holder is formed of synthetic resin as a material for weight reduction, its linear expansion coefficient is that of the metal plate and the piezoelectric sheet. It is larger than the head unit that is a laminate. For this reason, the position of the head unit fixed to the head holder sometimes fluctuates or tilts (parallelism deteriorates) due to a change in environmental temperature. As a result, there has been a problem that a plurality of ink coloring points on the paper are deviated, resulting in color misregistration and a reduction in image resolution .

In addition, if the piezoelectric actuator in the head unit is partially distorted in the stacking direction, not only pressure is applied to the pressure chamber, but also distortion occurs in other parts of the cavity unit, and pressure chambers in other parts In other words, there is a problem that so-called crosstalk occurs when the ink discharge operation is performed .

An object of the present invention is to solve the above-described problems, and to provide an ink jet printer head in which the position of the head unit is prevented from fluctuating or tilting due to a change in environmental temperature, and crosstalk is suppressed. Is.

In order to achieve the above object, an ink jet printer head according to a first aspect of the present invention includes a head unit configured by laminating a plurality of plates having a plurality of nozzles arranged in a row on the front surface. A metal frame located on the back side of the head unit and a synthetic resin head holder that supports the back side of the frame, the head unit including the plurality of nozzles and the pressure for each nozzle. A metal cavity unit having a chamber, a plurality of stacked piezoelectric sheets provided on the back side of the cavity unit, a common electrode for the plurality of pressure chambers sandwiching the piezoelectric sheet, and corresponding to each pressure chamber And by applying a voltage to the common electrode and the individual electrode, the piezoelectric sheet may be deformed by distortion in the stacking direction of the piezoelectric sheet. An actuator for applying an ejection pressure to the ink in each pressure chamber, wherein the rigidity of the frame is higher than the rigidity of the cavity unit, and the frame and the cavity unit are made of a material having a close linear expansion coefficient, and the cavity said frame along the back side of the unit is secured by an adhesive, wherein the frame is greater than the width of the actuator has an opening smaller than the width of said cavity unit, wherein the actuator includes: the frame It is directly bonded to the cavity unit in the opening of the frame so as not to contact, and the head unit is fixed to the head holder via the frame.

An ink jet printer head according to a second aspect of the present invention includes a cavity unit having a plurality of nozzles arranged in a line on the front surface and a pressure chamber for each nozzle, and provided on the back side of the cavity unit. An actuator that applies discharge pressure to the ink in the pressure chamber, a metal frame located on the back side of the cavity unit, and a synthetic resin head holder that supports the back side of the frame, the head unit comprising: A metal cavity unit having a plurality of nozzles and a pressure chamber for each nozzle, a plurality of stacked piezoelectric sheets provided on the back side of the cavity unit, and a common for a plurality of pressure chambers sandwiching the piezoelectric sheets An electrode and an individual electrode formed at a position corresponding to each pressure chamber, and the common electrode An actuator that applies discharge voltage to the ink in each of the pressure chambers by applying a voltage to another electrode due to distortion in the stacking direction of the piezoelectric sheets, and the frame has rigidity to suppress distortion of the cavity unit by the actuator Composed of a material, the frame is fixed with an adhesive along the back side of the cavity unit, and the frame has an opening larger than the width of the actuator and smaller than the width of the cavity unit; The actuator is directly bonded to the cavity unit in the opening of the frame so as not to contact the frame, and the cavity unit is fixed to the head holder via the frame. .

Further, an invention according to claim 3, wherein the ink jet printer head according to claim 1 or 2, the flexible cable that will be connected to the actuator, is drawn from the opening of the frame to the rear side of the frame It is characterized by being.

According to a fourth aspect of the present invention, there is provided the inkjet printer head according to any one of the first to third aspects, wherein the head holder is made of an adhesive for fixing the frame to the head holder on a bottom plate thereof. It has a pour hole.
According to a fifth aspect of the present invention, in the inkjet printer head according to the third aspect , the head holder has a slit through which the flexible cable is inserted in the bottom plate.
According to a sixth aspect of the present invention, in the ink jet printer head according to the first or second aspect , the head holder has an insertion hole through which a sleeve for supplying ink to the cavity unit is inserted in the bottom plate. It is characterized by having.

According to the invention of claim 1, the frame and the cabinet unit are made of metal, the rigidity of the frame is higher than the rigidity of the cavity unit, and the head unit and the frame are made of a material having a close linear expansion coefficient, Since the frame is fixed with an adhesive along the back side of the cavity unit, and the head unit is fixed to the head holder via the frame, the head unit is fixed to the head holder by a change in environmental temperature as in the past. The position of the ink fluctuates or tilts (the degree of parallelism deteriorates), resulting in misregistration at a plurality of ink coloring points on the paper, causing color misregistration, and reducing the resolution of the image. Can be reduced. The frame can be fixed to the cavity unit by arranging the actuator in the opening of the frame.

According to the invention of claim 2 , the frame and the cavity unit are made of metal, the frame is made of a material having rigidity that suppresses distortion of the cavity unit by the actuator, and the frame extends along the back side of the cavity unit. Since the cavity unit is fixed to the head holder via the frame by being fixed with an adhesive, if the piezoelectric actuator in the head unit is partially distorted in the stacking direction, pressure is applied to the pressure chamber. In addition to the above, it is possible to suppress the occurrence of so-called crosstalk when the ink discharge operation is performed in the pressure chamber of the other part due to distortion in the other part of the cavity unit. The frame can be fixed to the cavity unit by arranging the actuator in the opening of the frame.

According to the invention of claim 3 , the flexible cable connected to the actuator can be pulled out from the opening of the frame to the back side of the frame.

According to the fourth aspect of the present invention, the frame can be fixed to the head holder by pouring the adhesive from the pouring hole provided in the bottom plate of the head holder.
According to the fifth aspect of the present invention, the flexible cable connected to the actuator can be pulled out from the slit provided in the bottom plate of the head holder.

According to the sixth aspect of the present invention, the sleeve for supplying ink to the cavity unit can be inserted through the insertion hole provided in the bottom plate of the head holder.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a perspective view of an ink jet printer to which the present invention is applied, FIG. 2 is a plan view of the printer head according to the first embodiment viewed from the back side, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a plan view of the printer head viewed from the front side, FIG. 5A is a side view of the head unit attached to the frame, and FIG. 5B is a view of the head unit attached to the frame viewed from the back side. 6 is a sectional view taken along the line IV-IV in FIG. 5B, FIG. 7 is an enlarged perspective view of the bonding hole, FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. Is a perspective view of each part of the head unit, FIG. 10 is a partial perspective view of each part of the cavity unit, and FIG. 11 is a partially enlarged perspective view of each part of the cavity unit.

  As shown in FIG. 1, a color inkjet printer 100 according to the present invention includes, for example, an ink cartridge 61 in which four color inks of cyan, magenta, yellow, and black are partitioned and filled, and a sheet ( An ink jet printer head (hereinafter simply referred to as a printer head) 63 for printing on a recording medium) 62, a carriage 64 on which the ink cartridge 61 and the printer head 63 are mounted, and the carriage 64 in the transport direction of the paper 62 ( A drive unit 65 that reciprocates in a direction (main scanning direction, hereinafter referred to as X direction) orthogonal to the sub-scanning direction (hereinafter referred to as Y direction), and a platen that extends in the reciprocal movement direction of the carriage 64 and that is opposed to the printer head 63. A roller 66 and a purge device 67 are provided.

  The drive unit 65 is disposed at the lower end portion of the carriage 64 and extends parallel to the platen roller 66, the guide plate 72 is disposed at the upper end portion of the carriage 64 and extends parallel to the carriage shaft 71, and the carriage shaft 71. And the guide plate 72, and two pulleys 73 and 74 disposed at both ends of the carriage shaft 71, and a timing belt 75 wound around the pulleys 73 and 74.

  The carriage 64 joined to the timing belt 75 is supported by the carriage shaft 71 and the guide plate 72 and can reciprocate linearly by the driving force from one pulley 73 that rotates in accordance with the driving of the motor 76.

  A sheet 62 conveyed in the Y direction (sub-scanning direction) from a sheet feeding unit (not shown) is introduced between the platen roller 66 and the printer head 63 and is ejected by ink discharged from the printer head 63 as will be described later. Predetermined printing is performed, and then the paper is discharged.

  The purge device 67 is provided on the side of the platen roller 66 and is disposed so as to face the printer head 63 when the printer head 63 is in the reset position. The purge device 67 includes a purge cap 81 that abuts against an opening surface of the nozzles 11a of the printer head 63, which will be described later, a pump 82 and a cam 83, and an ink reservoir 84. Yes. When the printer head 63 is at the reset position, the defective ink containing bubbles and the like accumulated inside the printer head 63 is sucked by the pump 82 by driving the cam 83 so that the printer head 63 is recovered. Yes. The sucked defective ink is stored in the ink storage section 84.

  A wiper member 86 is disposed adjacent to the purge device 67 at a position on the platen roller 66 side in the purge device 67. The wiper member 86 is formed in a spatula shape, and wipes the nozzle surface of the printer head 63 as the carriage 64 moves. When the nozzle surface is wiped, the wiper member 86 protrudes upward, and when the nozzle surface is not wiped, it retracts downward.

  The cap 85 covers the plurality of nozzles 11a of the printer head 63 mounted on the carriage 64 that is returned to the reset position when printing is completed in order to prevent ink from drying.

As shown in FIG. 3, the printer head 63 includes a head unit 6 having a plurality of nozzles 11 a arranged in a row on the front surface (lower surface in FIG. 3), and a frame 50 positioned on the back side of the head unit 6. When, that have a head holder 1 positioned on the rear side of the frame 50.

  The head holder 1 includes the mounting portion 3 on which the ink cartridge 61 described above is mounted, and ink is supplied from the ink cartridge 61 to the head unit 6 via an ink supply sleeve 4 for each color described later. It has become so.

  First, the configuration of the head unit 6 will be described. As shown in FIGS. 9 to 11, the head unit 6 has a cavity unit 10 formed by laminating a plurality of metal plates, and is bonded to the cavity unit 10 via an adhesive or an adhesive sheet. The plate-type piezoelectric actuator 20 and a flexible flat cable 40 that is lap-joined on the back surface (upper surface) for electrical connection with an external device.

  As shown in FIG. 10, the cavity unit 10 has a structure in which five thin metal plates of a nozzle plate 11, two manifold plates 12, 12, a spacer plate 13, and a base plate 14 are overlapped and bonded respectively with an adhesive. It is configured. In this embodiment, each plate excluding the nozzle plate 11 is made of 42% nickel alloy steel plate and has a thickness of about 50 μm to 150 μm.

  As shown in FIG. 9, the head unit 6 of this embodiment is a long head that is provided with a large number of nozzles 11 a and is long in the Y direction (sub-scanning direction), and a printer to which the head unit 6 is attached. As shown in FIG. 2, the head 63 is also configured to be long in the Y direction (sub-scanning direction). The nozzles 11a of the head unit 6 are provided as a total of four nozzle rows 11b extending in the Y direction, as shown in FIG. 10, and these four rows of nozzle rows 11b are divided in half in the middle of the Y direction. The nozzle group 11c is composed of a total of four groups each including two rows. In the nozzle group 11c, the nozzle rows 11b and 11b are staggered at a constant pitch.

  The nozzle plate 11 is bonded to the lower manifold plate 12, and for each nozzle group 11 c, a large number of through passages 17 communicating with the nozzles 11 a are provided on the upper and lower manifold plates 12, 12 and the spacer plate 13. Along the side (Y direction), two rows of staggered arrays corresponding to the nozzles 11a are provided at a constant pitch. The two manifold plates 12 and 12 are provided with ink passages 12a and 12b extending along both sides of the row of through holes 17 for each nozzle group 11c. However, as shown in the enlarged view of FIG. 11, the ink passage 12 b in the lower manifold plate 12 is recessed so as to open only to the upper side of the manifold plate 12. The ink passages 12 a and 12 b are sealed by stacking the spacer plate 13 on the upper manifold plate 12. Further, these ink passages 12a and 12b correspond to the nozzle group 11c, and two sets sandwiching the through-hole 17 are set as two sets in the short side (X direction) direction, and in the middle of the long side (Y direction) direction. There are two sets, and a total of four sets are provided, and inks of different colors can be supplied from the end portions on both short sides.

  In addition, a plurality of narrow pressure chambers 16 extending along the short side (X direction) are formed in the base plate 14 in two rows for each nozzle group 11c. When the longitudinal reference lines 14a and 14b parallel to the staggered nozzle row are set (see FIG. 11), the tip 16a of the left pressure chamber 16 is positioned on the right longitudinal reference line 14a and The tip 16a of the pressure chamber 16 is located on the left longitudinal reference line 14b, and the tips 16a of the left and right pressure chambers 16 are alternately arranged. As a result, the pressure chambers 16 on both the left and right sides are alternately arranged so as to extend in opposite directions.

  The front end 16a of each pressure chamber 16 communicates with the spacer plate 13 and the manifold plates 12 and 12 through through passages 17, 17, and 17 that are similarly drilled in a staggered arrangement. On the other hand, the other end 16 b of each pressure chamber 16 communicates with the ink passages 12 a and 12 b in both the manifold plates 12 and 12 through a through hole 18 formed in the spacer plate 13. The other end 16 b of each pressure chamber 16 is formed to be recessed so as to open only on the lower surface side of the base plate 14.

  As a result, the ink that has flowed into the ink passages 12a and 12b from the ink supply ports 19a and 19b drilled in the both ends on the short side of the base plate 14 and the spacer plate 13 passes through the ink passages 12a and the through holes. After being distributed in each pressure chamber 16 through 18, the pressure chamber 16 passes through the through passages 17, 17, 17 and reaches the nozzle 11 a corresponding to the pressure chamber 16. (See FIG. 10). As described above, the ink passages 12a and 12b are divided into four groups in the long side direction and the short side direction, and different colors are supplied to each group. Therefore, each nozzle group 11c has one end in the long side direction. Ink of different colors is ejected in two groups in the side half, the other end half, and the short side direction.

  As shown in FIG. 9, a total of eight ink supply ports 19a are provided for each of the ink passages 12a and 12b. The ink supply port 19a is a set of two (one color), and a filter 29 for removing dust in the ink supplied from the ink cartridge 61 is fixed to the upper surface of the ink supply port 19a with an adhesive.

  In addition, on each filter 29 (a set of two ink supply ports 19a), cylindrical sleeves 4 project from the ink cartridge 61 in order to receive ink (see FIG. 6). Each sleeve 4 has an ink passage inside, and has a large-diameter portion 4a having a large outer diameter at the lower portion and a small-diameter portion 4b having a small outer diameter at the upper portion. 29 is firmly bonded and fixed to the substrate 29 with an epoxy resin or the like. Further, the outer periphery of the small diameter portion 4b is covered with a rubber packing or an O-ring which is an annular elastic seal body in order to prevent ink leakage when connecting to the flow path member connected to the ink cartridge 61. Fitted (not shown).

  Further, as shown in FIGS. 5, 6, and 9, bonding holes 51 are recessed at predetermined intervals along the left and right long sides extending in the Y direction on the back surface (upper surface) of the cavity unit 10. Yes. That is, the bonding hole 51 is formed as a bottomed hole without penetrating it. Further, as shown in FIG. 7, an air escape passage 52 that opens the bottom of the bonding hole 51 and the outside is opened at a side surface of the cavity unit 10 at a position that does not face a pouring hole 57 of the frame 50 described later. Has been. In this embodiment, since the nozzle plate 11 which is the lowermost layer of the cavity unit 10 is formed narrower than the other plates on both the short side (X direction) and the long side (Y direction), the bonding hole 51 is provided. The lower manifold plate 12 is the lowermost layer plate at a portion near both the left and right long sides where the is formed. Therefore, as shown in FIG. 7, among the plurality of plates constituting the cavity unit 10, the base plate 14 and the spacer plate 13 located on the back side are each provided with a through hole having a substantially rectangular shape in plan view in the plate thickness direction. By drilling and laminating the base plate 14, the spacer plate 13, and the upper and lower manifold plates 12, 12, the back (upper surface) side of the upper manifold plate 12 becomes the bottom, and a bottomed bonding hole 51 is formed. Has been.

  The upper manifold plate 12 has a plurality of air escape passages 52 with one end overlapping the through-hole formed in the base plate 14 and the other end opened on the side surface of the manifold plate 12. It is formed through the plate thickness. That is, the air escape passage 52 is formed so as to extend from the side surface near the bottom of the bonding hole 51 to the side surface of the head unit 6. The sectional area of the air escape passage 52 is smaller than the sectional area of the bonding hole 51. The portion of the air escape passage 52 that overlaps with the bonding hole 51 can be used as the substantial bonding hole 51 is extended.

  The through holes for forming the bonding holes 51 in the base plate 14 and the spacer plate 13 and the air escape passages 52 in the upper manifold plate 12 are formed simultaneously with other processing in each plate.

  In this embodiment, as shown in FIG. 7, five air escape passages 52 having a small cross-sectional area are provided in one bonding hole 51, but the number of air escape passages 52 can be arbitrarily set. In addition, the air escape passage 52 may be formed as a recess (half-etching) passage that opens to the upper surface side of the manifold plate 12 without penetrating the plate thickness of the upper manifold plate 12. The air escape passage 52 is preferably provided near the bottom of the bonding hole 51, but may be formed in a plate located in the middle in the stacking direction as necessary.

  On the other hand, the piezoelectric actuator 20 shown in FIG. 9 has a structure in which a plurality of piezoelectric sheets are laminated. As described in JP-A-4-341851, the lowermost piezoelectric sheet among the piezoelectric sheets and the upper side thereof On the upper surface of the odd-numbered piezoelectric sheet, narrow individual electrodes (not shown) are formed for each of the pressure chambers 16 in the cavity unit 10. A common electrode (not shown) common to the plurality of pressure chambers 16 is formed on the upper surface of the even-numbered piezoelectric sheets from the bottom. On the upper surface of the uppermost top sheet, as a surface electrode 30, an individual surface electrode electrically connected to each of the individual electrodes and a common electrode electrically connected to the common electrode The surface electrode is provided.

  The plate-type piezoelectric actuator 20 having such a configuration is laminated and fixed to the cavity unit 10 such that each individual electrode in the piezoelectric actuator 20 corresponds to each pressure chamber 16 in the cavity unit 10. The In this embodiment, since the cavity unit 10 is long, the two piezoelectric actuators 20 and 20 are fixed side by side along the long side (Y direction). At this time, the sizes of the cavity unit 10 and the two piezoelectric actuators 20 and 20 are set so that the bonding hole 51 and the ink supply sleeve 4 are exposed on the back surface (upper surface) side of the head unit 6. .

  Various wiring patterns (not shown) in the flexible flat cable 40 are electrically joined to the surface electrodes 30 on the surface on the back surface (upper surface) side of the piezoelectric actuator 20. In this embodiment, flexible flat cables 40 and 40 are joined to the two piezoelectric actuators 20 and 20, respectively. In addition, each flexible flat cable 40 of this embodiment uses a type in which an IC chip 40a is mounted.

  In this configuration, by applying a voltage between any individual electrode of the individual electrodes in the piezoelectric actuator 20 and the common electrode, the piezoelectric sheet is piezoelectrically applied to a portion corresponding to the individual electrode to which the voltage is applied. Due to the distortion in the stacking direction caused by this, the internal volume of the pressure chamber 16 corresponding to each individual electrode is reduced by this distortion, so that the ink in the pressure chamber 16 is ejected from the nozzle 11a in the form of droplets. Thus, predetermined printing is performed.

  In the head unit 6 of this embodiment, the two piezoelectric actuators 20 and 20 are fixed to one cavity unit 10, but the configuration and number of the head unit 6 are arbitrary. The head unit 6 may have a configuration in which one piezoelectric actuator 20 is fixed to one cavity unit 10, or a plurality of head units 6 in which one piezoelectric actuator 20 is fixed to one cavity unit 10 in this way. An arrangement may be used. The cavity plate 10 in the head unit 6 may be a ceramic material in addition to a metal material. Furthermore, the drive means of the ink jet printer of the present invention may be other types of the plate-like piezoelectric actuator 20 described above, or the vibration plate covering the back surface of the pressure chamber is vibrated by static electricity to inject ink into the nozzle 11a. It is also possible to have a configuration in which the liquid is discharged from

  Next, the frame 50 that is located on the back surface (upper surface) side of the head unit 6 and to which the head unit 6 is fixed via an adhesive will be described. The frame 50 is made of metal, and as shown in FIGS. 5 (a) and 5 (b), a substantially rectangular opening 56 long in the Y direction is formed at the center of a substantially rectangular flat plate long in the Y direction. It has a drilled shape. As described above, when the piezoelectric actuator 20 in the head unit 6 is partially distorted in the stacking direction, not only pressure is applied to the pressure chamber but also distortion is generated in the other part of the cavity unit 10. A so-called crosstalk occurs when the ink ejection operation is performed in the pressure chambers of other portions. Therefore, by making the frame 50 a material having high rigidity such as metal, distortion of the cavity unit 10 due to the operation of the piezoelectric actuator 20 can be suppressed, and crosstalk can be suppressed.

  Conventionally, the head unit is directly bonded and fixed to the bottom plate of the head holder. However, since the head holder is formed of synthetic resin as a material for weight reduction, its linear expansion coefficient is reduced by the metal plate and the piezoelectric element. It is larger than the head unit that is a laminate of sheets. For this reason, the position of the head unit fixed to the head holder sometimes fluctuates or tilts (parallelism deteriorates) due to a change in environmental temperature. As a result, there has been a problem that a plurality of ink coloring points on the paper are deviated, resulting in color misregistration and a reduction in image resolution. Therefore, for example, as described in Japanese Patent Application Laid-Open No. 2003-145752, when fixing the head unit to the bottom plate of the head holder which is the back side member, only the substantially intermediate portion of the adjacent head unit is bonded and fixed. Even if the temperature changes, a device has been devised to make the interval accuracy and parallelism of the nozzle rows constant.

  However, instead of directly bonding the head unit 6 to the synthetic resin head holder 1 as in the present invention, the head unit 6 is bonded to a metal frame 50 having a linear expansion coefficient close to that of the head unit 6. By configuring, it is possible to significantly reduce the above-described adverse effects caused by changes in the environmental temperature.

  As shown in FIGS. 5 and 6, the dimension W1 in the narrow width (X direction) direction of the opening 56 of the frame 50 is larger than the dimension W2 in the narrow width (X direction) direction of the piezoelectric actuator 20 in the head unit 6. And is smaller than the dimension W3 of the cavity unit 10 in the narrow width (X direction) direction. When the head unit 6 is attached to the front surface (lower surface) of the frame 50, the piezoelectric actuator 20 portion of the head unit 6 is fitted into the opening 56 as shown in FIG. Two flexible cables 40 and four sleeves 4 attached to the back surface (upper surface) of the head unit 6 are drawn upward from the portion 56.

  In this frame 50, an adhesive pouring hole 57 that can communicate with the bonding hole 51 of the head unit 6 is provided at a position corresponding to the bonding hole 51 along the left and right long sides. . In this embodiment, the pouring hole 57 is formed in a substantially rectangular shape in plan view, and the pouring hole 57 has a larger opening area than the bonding hole 51.

  Next, the head holder 1 that is located on the back surface (upper surface) side of the frame 50 and to which the frame 50 is fixed via an adhesive will be described. The head holder 1 is an injection-molded product made of a synthetic resin material such as polyethylene or polypropylene, and as shown in FIG. The substantially box-shaped internal space is also long in the Y direction, and the ink cartridge 61 can be detachably mounted from above as the mounting portion 3 described above. Further, the bottom plate 5 which is the lower surface of the mounting portion 3 is provided with a slit 53 for drawing out the flexible flat cable 40 fixed to the head unit 6 and four cylindrical sleeves 4 protruding from the head unit 6. Insertion holes 54 and 54 for insertion, and a second pouring hole 55 for adhesive for fixing the frame 50 to the head holder 1 are formed.

  The slit 53 is formed elongated along the long side (Y direction) near the center of the bottom 5. The insertion holes 54 and 54 are formed in a substantially elliptical shape at both ends on the short side of the mounting portion 3. The second pouring hole 55 is formed in a reverse trapezoidal shape in a side sectional view in which the area of the opening on the lower surface side in the bottom portion 5 is smaller than the area of the opening on the upper surface side, and both left and right long sides (Y direction) of the bottom portion 5. Are provided at a plurality of locations. The position of the second pouring hole 55 in the Y direction is arranged so as to be between the adjacent pouring holes 57 and 57 of the frame 50 on the lower surface side of the bottom portion 5.

  A method of fixing the head unit 6 and the frame 50 configured as described above to the head holder 1 with an adhesive will be described.

  First, the two flexible flat cables 40 attached to the head unit 6 and the four sleeves 4 are taken out from the opening 56 of the frame 50 to the rear side (upward), and the head unit 6 is moved to the front surface of the frame 50. (Position on the bottom surface) The pouring hole 57 for bonding the frame 50 and the bonding hole 51 of the head unit 6 are aligned. At this time, a positioning jig or the like may be used. Then, a large-diameter filling cylinder or the like is used from the respective casting hole 57 side of the frame 50 to each bonding hole 51 of the head unit 6, and as the adhesive 58, for example, a UV adhesive that is a photocurable adhesive is used. Inject at once.

  In the bonding hole 51, as the adhesive 58 is poured from above, the lower air escapes from the air escape passage 52, so that the adhesive 58 adheres to the bottom of the bonding hole 51 without accumulating air. The service hole 51 is filled. Then, the adhesive 58 is injected not only into the bonding hole 51 but also to an amount that fills most of the pouring hole 57 and is cured.

  Next, the frame 50 to which the head unit 6 is fixed is disposed on the front surface (lower surface) of the bottom plate 5 of the head holder 1. At this time, two sleeves 4 are respectively inserted into the insertion holes 54, 54 formed in the bottom plate 5, and the two flexible flat cables 40 are pulled out from the slits 53. Then, the adhesive 58 is injected into the second pouring hole 55 and cured, and the frame 50 is fixed to the head holder 1. In this configuration, since the air escape passage 52 is provided in the vicinity of the bottom of the bonding hole 51, air does not collect at the bottom but escapes to the outside. Therefore, the adhesive is collectively applied to each bonding hole 51 of the head unit 6. 58 can be injected, and the time required for the bonding operation can be greatly shortened. In particular, when a highly viscous adhesive 58 is injected so as to cover the bonding hole 51 from above, the air can be quickly released to the air passage 52 by the pressure to flow below the adhesive 58 itself.

  Further, the air escape passage 52 of the head unit 6 is not provided at a position facing the flow hole 57 of the frame 50, and the cross-sectional area of the air escape passage 52 is set smaller than the cross-sectional area of the bonding hole 51. Therefore, the adhesive 58 having a large viscous resistance can be prevented from leaking from the air escape passage 52 with the injection.

  The adhesive 58 fills the bonding hole 51 without containing air, thereby contacting all of the bottom and side surfaces of the bonding hole 51 and increasing the contact area thereof, as well as the bonding hole 51. To the casting hole 57, the anchor effect (action) between the head unit 6 and the frame 50 is enhanced, and the head unit 6 and the frame 50 are fixed with extremely high adhesive strength. I can do this.

  Further, since a plurality of bonding holes 51 are provided along both long sides of the head unit 6 and the anchor effect is exhibited at a plurality (large number) of locations, the bonding strength as a whole can be greatly improved. .

  Also, as compared with the conventional case where the four corners of the head unit 6 are superficially covered with an adhesive, the adhesive 58 has a relatively small hole 51 for bonding, a casting hole 57, and a second hole. Since only the amount of the filling hole 55 is used, even if a plurality of bonding holes 51 are provided, the amount of adhesive used as a whole can be reduced and the cost of the adhesive can be reduced.

  In addition, since the bonding holes 51 are provided at substantially equal intervals along both long sides of the head unit 6, it is possible to equalize the shrinkage distortion of the adhesive 58 and to minimize misalignment due to curing.

  Further, when a UV adhesive is used for the adhesive 58, the bonding time can be shortened. In particular, when a UV adhesive of a type whose curing is accelerated by contact with metal is used, the filled adhesive is a large area metal in the bonding hole 51 provided in the head unit 6 which is a laminate of metal plates. Since it is in contact with the surface, curing in the bonding hole 51 is promoted, which can contribute to shortening the working time and greatly improving the manufacturing efficiency.

1 is a perspective view of an ink jet printer to which the present invention is applied. It is the top view which looked at the printer head in a 1st embodiment from the back side. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. It is the top view which looked at the printer head from the front side. (A) is the side view of the state which attached the head unit to the flame | frame, (b) is the top view which looked at the state which attached the head unit to the flame | frame from the back side. FIG. 6 is a cross-sectional view taken along the line IV-IV in FIG. It is an expansion perspective view of the hole for adhesion | attachment. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7. It is a perspective view of each component of a head unit. It is a fragmentary perspective view of each component of a cavity unit. It is a partial expansion perspective view of each component of a cavity unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head holder 3 Mounting part 4 Sleeve 5 Bottom plate 6 (Inkjet) Head unit 10 Cavity unit 11 Nozzle plate 11a Nozzle 11b Nozzle row 11c Nozzle group 12 Manifold plate 13 Spacer plate 14 Base plate 16 Pressure chamber 17 Through passage 19a Ink supply port 20 Piezoelectric Actuator 29 Filter 30 Surface electrode 40 Flexible flat cable 50 Frame 51 Adhesion hole 52 Air escape passage 53 Slit 54 Insertion hole 55 Second injection hole 56 Opening part 57 Injection hole 58 Adhesive 61 Ink cartridge 62 Paper 63 (Inkjet) printer Head 64 Carriage 100 Inkjet printer

Claims (6)

A head unit having a plurality of nozzles arranged in a row on the front surface and configured by laminating a plurality of plates;
A metal frame located on the back side of the head unit;
With a synthetic resin head holder that supports the back side of the frame,
The head unit includes a plurality of nozzles and a metal cavity unit having a pressure chamber for each nozzle, a plurality of stacked piezoelectric sheets provided on the back side of the cavity unit, and a plurality of sandwiched piezoelectric sheets. A common electrode for the pressure chambers and individual electrodes formed at positions corresponding to the pressure chambers, and applying voltage to the common electrode and the individual electrodes causes distortion in the stacking direction of the piezoelectric sheets. An actuator that applies discharge pressure to the ink in each pressure chamber,
The rigidity of the frame is higher than the rigidity of the cavity unit;
The frame and the cavity unit are made of a material having a close linear expansion coefficient, and the frame is fixed with an adhesive along the back side of the cavity unit,
The frame has an opening larger than the width of the actuator and smaller than the width of the cavity unit;
The actuator is directly bonded to the cavity unit in the opening of the frame so as not to contact the frame,
An ink jet printer head, wherein the head unit is fixed to the head holder via the frame. A cavity unit having a plurality of nozzles arranged in a row on the front surface and a pressure chamber for each nozzle;
An actuator that is provided on the back side of the cavity unit and applies discharge pressure to the ink in the pressure chamber;
A metal frame located on the back side of the cavity unit;
With a synthetic resin head holder that supports the back side of the frame,
The head unit includes a plurality of nozzles and a metal cavity unit having a pressure chamber for each nozzle, a plurality of stacked piezoelectric sheets provided on the back side of the cavity unit, and a plurality of sandwiched piezoelectric sheets. A common electrode for the pressure chambers and individual electrodes formed at positions corresponding to the pressure chambers, and applying voltage to the common electrode and the individual electrodes causes distortion in the stacking direction of the piezoelectric sheets. An actuator that applies discharge pressure to the ink in each pressure chamber,
The frame is made of a material having rigidity to suppress distortion of the cavity unit by the actuator,
The frame is fixed with an adhesive along the back side of the cavity unit,
The frame has an opening larger than the width of the actuator and smaller than the width of the cavity unit;
The actuator is directly bonded to the cavity unit in the opening of the frame so as not to contact the frame,
An ink jet printer head, wherein the cavity unit is fixed to the head holder via the frame. Flexible cable connected to the actuator, an ink jet printer head according to claim 1 or 2, characterized in that it is drawn out to the rear side of the frame from the opening of the frame. The ink jet printer head according to any one of claims 1 to 3 , wherein the head holder has a pouring hole for an adhesive for fixing the frame to the head holder on a bottom plate thereof. The ink jet printer head according to claim 3 , wherein the head holder has a slit through which the flexible cable is inserted in a bottom plate thereof. The head holder has, at its bottom plate, the ink jet printer head according to claim 1 or 2, characterized in that it has an insertion hole for inserting the sleeve for supplying ink to the cavity unit.

Images