JP2009190188A - Inkjet head and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head capable of uniformizing heat distribution in an actuator. <P>SOLUTION: The inkjet head 1 which is attached to a carriage of an inkjet recording device and to which ink is supplied to eject the ink from a nozzle hole is equipped with: a supporting body 11 having a plate-type base part 18 and a fixed part 19 which is provided at one end of the base part 18 and whose both ends in a longitudinal direction are fixed on the carriage; the actuator 12 having a plurality of groove-like ink chambers and attached to one surface of the base part 18 so as to generate driving force for ejecting the ink; and a nozzle plate formed in a plate shape having a plurality of nozzle holes and bonded integrally with the actuator 12. The base part 18 of the supporting body 11 is formed such that its surface to which the actuator 12 is attached is in non-contact with the actuator 12 in heat insulating areas R1 of predetermined length from both ends of the actuator 12 in a direction orthogonal to the ink chamber. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet head mounted on an ink jet recording apparatus and an ink jet recording apparatus.

  In general, in an ink jet recording apparatus, printing is performed by reciprocating a carriage on which a plurality of ink jet heads are mounted while facing a sheet or the like, and ejecting ink droplets from nozzles of the ink jet head.

There are various mechanisms for ejecting ink. Among them, the wall surface of the ink chamber is driven by an actuator including a plurality of groove-shaped ink chambers and piezoelectric elements, and ink is moved from the ink chamber to the nozzle holes for ejection. Such a method is well known (for example, see Patent Document 1).
JP 2007-223251 A

  By the way, when the actuator is operated by the method of Patent Document 1 to generate a driving force for ejecting ink, the actuator generates heat by being driven. Usually, the actuator is fixed to the flat portion of the support that supports the inkjet head with an adhesive or the like. And a part of support body located in the longitudinal direction both ends of an actuator is attached to the carriage, and the head is being fixed to the carriage.

  Since the carriage is usually made of metal, heat is transferred from both end portions of the actuator close to the above-described attachment portion to the carriage through the attachment portion to be radiated. As a result, the temperature tends to decrease at both ends in the longitudinal direction of the actuator, and a temperature difference occurs between the longitudinal central portion away from the attachment site.

  Since the viscosity of the ink changes depending on the temperature, if the above temperature difference occurs, the viscosity of the ink inside the actuator becomes non-uniform among the ink chambers, the ink ejection speed varies, and the ink landing position shifts. There is a problem that occurs.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an ink jet head and an ink jet recording apparatus that can uniformly release heat generated by an actuator and make the heat distribution in the actuator uniform. And

  A first aspect of the present invention is an ink jet head that is attached to a carriage of an ink jet recording apparatus and that is supplied with ink and ejects the ink from a nozzle hole, and includes a plate-like base portion and one end of the base portion. A support body having a fixing portion provided at both ends in the longitudinal direction and fixed to the carriage; and a plurality of groove-shaped ink chambers that are attached to one surface of the base portion and discharge the ink. An actuator that generates a driving force; and a nozzle plate that is formed in a plate shape having a plurality of the nozzle holes and is integrally joined to the actuator; and the base portion of the support body has a surface to which the actuator is attached. In the heat insulating region of a predetermined length from both ends of the actuator in a direction orthogonal to the ink chamber, the actuator Characterized in that it is formed to be a non-contact state.

  According to the ink jet head of the present invention, since the actuator and the base portion of the support body are not in contact with each other in the heat insulating region including both ends of the actuator in the direction orthogonal to the ink chamber, the carriage having the fixed portion attached from both ends Heat is not easily transmitted to the actuator, and the heat generated by the actuator is evenly released, so that the temperature of each ink chamber of the actuator becomes more uniform.

  The base portion of the support may be formed in a tapered shape so that the distance from the actuator increases as it approaches both ends of the actuator in a direction orthogonal to the ink chamber. In this case, the heat generated by the actuator is released more uniformly to the base portion, and the temperature uniformity of each ink chamber can be further increased.

  The base portion of the support has a plurality of notches on a surface to which the actuator is attached, and the size of each of the notches in a direction perpendicular to the ink chamber is closer to the heat insulating region. You may set so that it may become large. In this case, the contact area between the actuator and the base portion decreases as it approaches the heat insulation region, and the heat of the actuator is hardly transmitted to the base portion. Therefore, it is possible to suppress the occurrence of temperature unevenness in each ink chamber depending on the distance to both ends of the fixed portion fixed to the carriage.

  The actuator may have a heat insulating material attached to at least a part of the periphery in the heat insulating region. In this case, the heat insulating property in the heat insulating region can be further stabilized.

  An ink jet recording apparatus according to a second aspect of the present invention includes the ink jet head of the present invention.

  According to the ink jet head and the ink jet recording apparatus of the present invention, it is possible to provide an ink jet head and an ink jet recording apparatus that can uniformly dissipate heat generated by the actuator and make the heat distribution in the actuator uniform.

An ink jet head (hereinafter simply referred to as “head”) and an ink jet recording apparatus according to an embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a diagram illustrating a configuration of an ink jet recording apparatus 2 including a head 1 according to the present embodiment. The ink jet recording apparatus 2 is a so-called wide format recording apparatus having a printing width of 100 inches or more, and includes a head unit 3 that performs a printing operation, an ink supply unit 4 that supplies ink to the head unit 3, and a head unit 3. A capping unit 5 for performing maintenance, a wiping unit 6 for cleaning the head unit 3, a head unit transporting unit 7 for moving the head unit 3, a paper transporting unit 8 for transporting paper on which printing is performed, And a leg portion 9 that supports the mechanism.

  The head unit 3 includes a plurality of heads 1 and a carriage 10 to which the heads 1 are attached. Each head 1 corresponds to one color ink. The head unit 3 of the present embodiment is compatible with six color inks, and the six heads 1 are attached to the carriage 10, but the number of heads attached to the head unit 3 is not particularly limited, and a plurality of heads 1 It may be assigned to one color.

FIG. 2 is a perspective view showing the head 1, and FIG. 3 is an exploded view showing the head 1. As shown in FIGS. 2 and 3, the head 1 includes a support 11 that supports the entire structure, an actuator 12 that is attached to the support 11 and generates a driving force for discharging ink, and discharge of the actuator 12. A circuit board 14 on which an IC (integrated circuit) 13 or the like as a control unit to be controlled is mounted, an ink storage unit 15 for supplying ink to the actuator 12, and a nozzle plate 16 in which a plurality of nozzle holes for discharging ink are formed. And a nozzle cap 17 that supports the actuator 12 and the nozzle plate 16.
In FIG. 3, the ink storage unit 15 is omitted.

The support 11 includes a plate-like base portion 18 and a fixing portion 19 that is attached to one end of the base portion 18 and is substantially perpendicular to the base portion 18.
The base portion 18 and the fixing portion 19 are formed by die casting a metal such as aluminum. An actuator 12, a circuit board 14, and the like are attached to the base portion 18.

  The fixing portion 19 is formed in a substantially U shape, and the nozzle cap 17 is attached to the surface opposite to the base portion 18. Further, screw holes 19 </ b> A for attaching the head 1 to the carriage 10 are provided at both ends in the longitudinal direction of the fixed portion 19.

  The actuator 12 has a known configuration having a plurality of groove-shaped ink chambers 20 and a piezoelectric element (not shown). The plurality of ink chambers 20 are arranged in the width direction of the ink chambers 20, and a voltage is applied to the piezoelectric element, whereby the walls of the ink chambers 20 are controlled based on the control of the IC 13 on the circuit board 14. Is driven to generate a driving force, and ink in the ink chamber 20 is ejected.

  The circuit board 14 is attached to the base portion 18 with screws or the like. The circuit board 14 is connected to the actuator 12 by the flexible board 14A, and controls the operation of the actuator 12 as described above.

  FIG. 4 is a view of the support 11 and the actuator 12 as seen from the fixed portion 19 side. On the base portion 18, the lower surface of the actuator 12 is fixed with an adhesive or the like. One end 12 </ b> A in the longitudinal direction of the actuator 12 (that is, the direction orthogonal to the longitudinal direction of the ink chamber 20) is in contact with the fixed portion 19 for positioning the ink chamber 20.

  As shown in FIG. 4, the upper surface of the base portion 18 and the lower surface of the actuator 12 are in contact with each other in a certain range including the center in the longitudinal direction of the actuator 12. However, in the heat insulation region R1 having a predetermined length from both longitudinal ends of the actuator 12, for example, 10 millimeters (mm), the upper surface of the base portion 18 and the lower surface of the actuator 12 are gradually separated toward the both ends. At least a part of the base portion 18 is processed into a tapered shape. With this shape, the base portion 18 and the actuator 12 are not in contact with each other in the heat insulating region R <b> 1, and an air layer A is formed around the actuator 12. The distance between the base 18 and the actuator at both ends is set to 1 mm, for example.

  The length of the heat insulating region R1 separating the actuator 12 and the base portion 18 can be arbitrarily set. However, in order to improve the heat flow when the actuator 12 generates heat, which will be described later, the groove shape of the ink chamber 20 Among the ink chambers 20 aligned in the width direction, the length of R1 is preferably set so that the ink chambers 20A at both ends do not cover the heat insulating region R1. Moreover, the length of heat insulation area | region R1 may be set to a different length by right and left. For example, the heat insulating area on the side of the end portion 12 </ b> A that is in contact with the fixing portion 19 may be set longer to suppress heat conduction to the fixing portion 19.

  The ink reservoir 15 is connected to the ink supply unit 4. The ink supplied from the ink supply unit 4 is temporarily stored in the ink storage unit 15 and the pressure is adjusted, and then the ink is supplied to the actuator 12 through the flow path member 36 attached so as to cover the ink chamber 20 of the actuator 12. Supplied.

  The nozzle plate 16 is integrally joined to the actuator 12 with an adhesive or the like so that the nozzle hole communicates with the ejection port of each ink chamber of the actuator 12. The nozzle cap 17 has a through-hole through which the actuator 12 can be inserted, supports the inserted actuator 12, and is integrally joined to a portion of the nozzle plate 16 that is not joined to the actuator 12, thereby connecting the nozzle plate 16. To support.

  As shown in FIG. 5, the head 1 configured with each of the above-described mechanisms has a nozzle cap 17 in the head installation hole 10 </ b> A formed on the lower surface of the carriage 10, that is, the surface facing the paper transport unit 8. It is inserted and installed so that the nozzle plate 16 is exposed. Then, a screw is inserted into the screw hole 19A of the fixing portion 19, and the carriage 10 and the head 1 are fixed integrally. At this time, the vertical direction in FIG. 5 is the longitudinal direction of each ink chamber of the actuator 12.

  Returning to FIG. 1, the ink supply unit 4 includes a replaceable ink cartridge 21 and a plurality of ink tubes 22. The ink cartridge 21 is filled with six colors of ink, and each is supplied to the corresponding ink reservoir 15 of the head 1 via the ink tube 22.

The capping unit 5 includes a plurality of caps 23 that detachably adhere to each head 1 and seal the nozzle plate 16, and a suction pump 24 that sucks bubbles and ink from the nozzles of the head 1. .
In addition to serving as a tray for the ink sucked from the nozzles, the cap 23 is in close contact with the head 1 to prevent the nozzle plate 16 from drying when the inkjet recording apparatus 2 is not used.
The suction pump 24 performs maintenance of the head unit 3 by sucking old ink or minute bubbles from the inside of the nozzle, and arranges the meniscus of the nozzle to stabilize printing by the head unit 3. The ink or the like sucked by the suction pump 24 is stored in a waste liquid bottle 25 provided below.
Further, the suction pump 24 is also used as a pump for filling the head 1 with ink. This filling method is called a suction filling method. Moreover, although this embodiment demonstrates using said suction filling method, there exists a method called a pressurization filling method in addition to the filling method. In this case, a pump (not shown) is provided in the middle of the ink tube 22, and the head 1 is filled with ink by pressurizing the ink in the ink tube 22.

  The head unit transport unit 7 has a known configuration, and the head unit 3 is moved along the carriage rail 27 by a moving mechanism 26 such as a motor.

  The paper transport unit 8 includes a roller unit 28 composed of a pinch roller and a grid roller for feeding paper, a rotation mechanism 29 such as a motor for rotating the roller unit 28, and a platen 30 for supporting the paper, and a head unit transport unit Like FIG. 7, it has a known configuration.

The operation during the printing operation of the inkjet recording apparatus 2 configured as described above will be described below.
When the user sets paper to be printed on the paper transport unit 8 and starts printing, ink is supplied from the ink supply unit 4 to the ink storage unit 15 of each head 1 mounted on the carriage 10. The ink stored in the ink storage unit 15 is adjusted in pressure and supplied to each ink chamber 20 of the actuator 12.

The piezoelectric element of the actuator 12 is driven by a print signal based on the content to be printed while being controlled by the IC 13 on the circuit board 14. As a result, the wall surface of each ink chamber 20 of the actuator 12 is driven, and the ink in the ink chamber 20 moves toward the nozzle plate 16 and is ejected from the nozzle holes toward the paper.
The set paper is intermittently sent in the paper transport unit 8 and the head unit 3 ejects ink along the carriage rail 27 as described above by the head unit transport unit 7 so that a desired document is printed on the paper. And images are printed.

  When ink is ejected from the actuator 12, the actuator 12 generates heat as the wall surface of each ink chamber 20 is driven by the piezoelectric element. The generated heat is transmitted to the base portion 18 from the upper surface of the base portion 18 of the support 11 that is in contact with the lower surface of the actuator 12. Then, the generated heat is radiated by escaping from both ends in the longitudinal direction of the fixing portion 19 provided with the screw holes 19A to the carriage 10.

However, in the heat insulating region R1 including both longitudinal ends of the actuator 12, as described above, the actuator 12 and the base portion 18 are not in contact with each other, and an air layer A is formed therebetween. Therefore, heat is not directly transferred from both ends in the longitudinal direction of the actuator 12 to the base portion 19, and heat transfer from the actuator 12 to the base portion 18 is exclusively performed in the heat insulating regions R1 at both ends as indicated by arrows in FIG. Heat is released from each ink chamber 20 to the support 11 almost uniformly. As a result, a temperature difference between the ink chambers 20 is suppressed.
Although one end 12A of the actuator 12 is abutted against the fixed portion 19, the bottom surface of the ink chamber 20A closest to the fixed portion 19 is in contact with the base portion 18, so that most of the generated heat is generated. Since it escapes from the base portion 18, it hardly affects the heat distribution in the ink chamber 20.

  According to the head 1 of the present embodiment, since the heat insulating region R1 including both ends in the longitudinal direction of the actuator 12 is not in contact with the base portion 18 of the support 11 to be bonded, the ink chambers 20 near both ends. Thus, the heat generated in the step is hardly transmitted directly to both ends of the fixing portion 19, and is radiated to the carriage 10 from the lower base portion 18 through the fixing portion 19. Therefore, a temperature difference is unlikely to occur between both ends and the center of the plurality of arranged ink chambers, and the temperature of each ink chamber is kept uniform, so that the ink viscosity in each ink chamber is also kept uniform, and the ink jet recording apparatus The printing accuracy of 2 can be maintained at a high level.

  In addition, since the upper surface of the base portion 18 is tapered so that the distance between the actuator 12 and the base portion 18 in the heat insulating region R1 decreases toward the center in the longitudinal direction of the actuator 12, the distance from the actuator 12 is increased. The heat escape becomes more uniform. Therefore, the temperature difference in the actuator 12 can be further reduced, and the temperature of each ink chamber 20 can be made uniform.

  In the present embodiment, an example in which the base portion 18 is processed into a tapered shape has been described. However, unlike the modification example illustrated in FIG. 7, the base portion 18A does not have a tapered shape in the region R1, and is not in contact with the actuator 12. A certain effect can be obtained only by processing the upper surface of the base portion 18A into a shape to be brought into contact.

  Further, in order to prevent heat transfer from the end portion 12A of the actuator 12 in contact with the fixed portion 19 more reliably, a notch 19B is formed on the wall surface of the fixed portion 19 with which the actuator 12 is abutted for positioning as necessary. Thus, the contact area between the actuator 12 and the fixed portion 19 may be made smaller while positioning the ink chamber is possible.

Next, a second embodiment of the present invention will be described with reference to FIG. The difference between the head 31 of the present embodiment and the head 1 described above is the shape of the base portion of the support.
In addition, about the structure which is common in the above-mentioned head 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

FIG. 8 is a view of the support body 32 and the actuator 12 of the head 31 as viewed from the fixed portion 34 side. A plurality of notches are provided on the upper surface of the base portion 33 with which the lower surface of the actuator 12 contacts.
As shown in FIG. 8, the dimension of each notch in the longitudinal direction of the actuator 12 is set to be the smallest near the center of the actuator and gradually increase as it approaches both ends of the row of ink chambers 20. That is, the contact area between the actuator 12 and the base portion 33 is set to be smaller as the thermal insulation region R1 is approached.
Moreover, the base part 33 of this embodiment is processed so that it may not have a taper shape in heat insulation area | region R1.

  According to the head 31 of the present embodiment, a plurality of notches are provided on the upper surface of the base portion 33 that contacts the actuator 12, and the actuator 12 and the base portion 33 become closer to both ends of the row of the ink chambers 20 due to the notches. The contact area is set to be small. Therefore, near the center of the row of ink chambers 20 having a large contact area, heat generated by the actuator 12 is easily transmitted to the base portion 33, and near both ends of the row, heat is less likely to be transmitted to the base portion 33 than near the center. As a result, the heat radiation from each ink chamber 20 is less affected by the difference in distance to both ends of the fixed portion 34 attached to the carriage 10, and the temperature of each ink chamber can be made more uniform.

  While the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. .

For example, in each of the above-described embodiments, the example in which the air layer A is secured around the actuator 12 in the heat insulating region R1 has been described, but the present invention is not limited to this.
As an example, a heat insulating material 35 may be disposed between both ends of the actuator 12 and the base portion 18A in the heat insulating region R1, as in the modification shown in FIG. If it does in this way, while the heat insulation of the heat insulation area | region R1 will be stabilized by the heat insulating material 35, since the both ends of the actuator 12 are supported by the heat insulating material 35, a deformation | transformation etc. of the both ends of the actuator 12 without a support can be prevented.

  At this time, the material of the heat insulating material 35 is not particularly limited, and various known heat insulating materials can be appropriately selected and used. Moreover, the arrangement position of the heat insulating material 35 is not particularly limited. Therefore, if the above-mentioned actuator support effect is not considered, for example, it may be provided only above the actuator 12. Further, in the heat insulating region R1, a part of the air layer A described above is formed by laying a heat insulating material on the entire surface between the lower surface of the actuator 12 and the base portion 18A or arranging a heat insulating material all around the actuator 12. Or it is also possible to make it the structure which replaced the whole with the heat insulating material.

It is a figure which shows an inkjet recording device provided with the inkjet head of 1st Embodiment of this invention. It is a perspective view which shows the same inkjet head. It is a figure which decomposes | disassembles and shows the same inkjet head. It is the figure which looked at the support body and actuator of the inkjet head which were seen from the fixed part side of the support body. It is a figure which shows the attachment state to the carriage of the inkjet head. It is a figure which shows the flow of the heat which generate | occur | produced with the actuator in the inkjet head. It is a figure which shows the support body and actuator of an inkjet head of the modification of the embodiment. It is the figure which looked at the support body and actuator of the inkjet head of 2nd Embodiment of this invention from the fixing | fixed part side of the support body. It is the figure which looked at the support body and actuator of the inkjet head of the modification of this invention from the fixing | fixed part side of the support body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 31 Inkjet head 2 Inkjet recording apparatus 10 Carriage 11, 32 Support body 12 Actuator 16 Nozzle plate 18, 18A, 33 Base part 19, 34 Fixed part 20, 20A Ink chamber 35 Insulation material R1 Insulation area

Claims (5)

An inkjet head that is attached to a carriage of an inkjet recording apparatus and that is supplied with ink and ejects the ink from a nozzle hole,
A support having a plate-like base portion and a fixing portion provided at one end of the base portion and having both longitudinal ends fixed to the carriage;
An actuator having a plurality of groove-shaped ink chambers and attached to one surface of the base portion to generate a driving force for discharging the ink;
A nozzle plate formed into a plate shape having a plurality of the nozzle holes and joined integrally with the actuator;
With
The base portion of the support is such that the surface on which the actuator is attached is not in contact with the actuator in a heat insulating region having a predetermined length from both ends of the actuator in a direction orthogonal to the ink chamber. An ink-jet head formed by the method described above.   The base portion of the support is formed in a tapered shape so that the distance from the actuator increases as the actuator approaches both ends of the actuator in a direction orthogonal to the ink chamber. 2. An ink jet head according to 1.   The base portion of the support has a plurality of notches on a surface to which the actuator is attached, and the size of each of the notches in a direction perpendicular to the ink chamber is closer to the heat insulating region. The inkjet head according to claim 1, wherein the inkjet head is set to be large.   4. The inkjet head according to claim 1, wherein a heat insulating material is attached to at least a part of a periphery of the actuator in the heat insulating region. 5.   An inkjet recording apparatus comprising the inkjet head according to claim 1.

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