JP2007136840A - Carriage and droplet discharge device - Google Patents

Abstract

An object of the present invention is to provide a carriage and a droplet discharge device capable of suppressing deterioration in image quality even when a piezoelectric actuator is thin and printing with excellent print quality.
A substrate having a mounting surface of a droplet discharge head 1 provided with a piezoelectric actuator 6 and a frame 7 for fixing the droplet discharge head 1 mounted on the mounting surface to the substrate are provided. In the state where the carriage 2 is mounted with the droplet discharge head 1, the natural frequency of the print region of the droplet discharge head 1 surrounded by the frame 7 is the print frequency when the carriage 2 moves for printing. A carriage having a larger frequency than that generated in the region, and a droplet discharge device including the carriage. The carriage 2 preferably includes a frame support 7a.
[Selection] Figure 1

Description

  The present invention relates to a carriage and a droplet discharge device, and more particularly, to a carriage and a droplet discharge device that can be suitably used for a printer, a copier, a facsimile, a composite machine thereof, and the like.

  In recent years, with the spread of personal computers and the development of multimedia, the use of ink jet recording apparatuses as recording apparatuses that output information to recording media is rapidly expanding. Such an ink jet recording apparatus is equipped with a droplet discharge head, and this type of droplet discharge head includes a heater as a pressurizing means in an ink flow path filled with ink. A thermal head system that heats and boils ink, pressurizes the ink with bubbles generated in the ink flow path, and discharges it as an ink flow from the ink discharge hole, and a part of the wall of the ink flow path filled with ink. A piezoelectric method is generally known in which a displacement element is bent and displaced, and ink in an ink flow path is mechanically pressurized and discharged as an ink flow from an ink discharge hole.

  Here, as a droplet discharge head used in an inkjet recording apparatus using a piezoelectric method, for example, a piezoelectric layer is formed on the main surface of a substrate provided with a plurality of pressure chambers in which an ink flow path and an ink discharge hole communicate with each other. There has been proposed a liquid droplet ejection head provided with a piezoelectric actuator in which a common electrode is formed on one main surface and a plurality of individual electrodes are formed on the other main surface (Patent Document 1).

  FIG. 9 is a schematic cross-sectional view showing a general droplet discharge head as described in Patent Document 1. In FIG. As shown in the figure, this droplet discharge head has a plurality of ink pressurizing chambers 101 arranged side by side, and a piezoelectric actuator 6 on a flow path member 8 in which a partition wall 102 is formed as a wall for partitioning each ink pressurizing chamber 101. Is provided.

  In the piezoelectric actuator 6, a piezoelectric ceramic layer 106 and individual electrodes 107 are laminated in this order on a piezoelectric diaphragm 105 having a common electrode 110 provided on the upper surface, and a plurality of individual electrodes 107 are arranged on the surface of the piezoelectric ceramic layer 106. Thus, a plurality of piezoelectric elements 108 are formed. The piezoelectric actuator 6 is mounted on the flow path member 8 so that the positions of the ink pressurizing chamber 101 and the drive electrode 107 are aligned.

  The droplet discharge head applies ink between the common electrode 110 and a predetermined individual electrode 107 to displace the piezoelectric ceramic layer 106 immediately below the individual electrode 107, thereby adding ink in the ink pressurizing chamber 101. The ink droplets are ejected from the nozzle 109 opened at the bottom of the flow path member 8.

  Such a droplet discharge head is attached to a carriage that is transported along a carriage axis by a carriage motor, and reciprocates in the main scanning direction together with the carriage. The carriage, carriage shaft and the carriage motor constitute moving means for moving the droplet discharge head and the recording medium relative to each other.

  On the other hand, a recording medium such as paper is sandwiched between a pair of conveyance rollers, and is conveyed in the sub-scanning direction orthogonal to the main scanning direction by the conveyance rollers. Then, the carriage moves to a predetermined position of the recording medium, the piezoelectric actuator 6 of the droplet discharge head attached to the carriage is vibrated to pressurize the ink, and ink droplets are discharged from the nozzle 109 toward the recording medium.

  Recently, in order to increase the amplitude of vibration in order to increase the image quality and increase the number of colors of the inkjet printer, the nozzles 109 are arranged at a high density and a larger pressure is applied to the liquid such as ink. It has been proposed to reduce the thickness of the piezoelectric actuator 6.

For example, Patent Document 2 includes a liquid droplet ejecting device that includes a piezoelectric material plate for deforming at least a part of a wall surface of a liquid chamber, and that ejects liquid droplets from the liquid chamber using predetermined deformation of the piezoelectric material plate. An apparatus (droplet discharge apparatus) is described. The droplet ejecting apparatus described in this document is a plate-like piezoelectric actuator so that nozzles can be arranged at high density and a sufficient amount of deformation can be applied to the piezoelectric material plate.
However, the droplet discharge device described in Patent Document 2 has a problem that the image quality deteriorates.

  As a result of examining the cause of image quality deterioration, the present inventor has obtained the following knowledge. That is, when the carriage is moved with the droplet discharge head mounted, unnecessary vibration is generated in the print region of the droplet discharge head surrounded by a frame for fixing the droplet discharge head to the carriage. The occurrence of this unnecessary vibration is significant when the piezoelectric actuator of the droplet discharge head is thin, and the unnecessary vibration changes the interval between the droplet discharge head and the print medium. Deviation occurs and image quality deteriorates.

JP 11-34321 A JP 2002-292865 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a carriage and a droplet discharge device that can suppress a decrease in image quality even when the thickness of a piezoelectric actuator is thin and can perform printing with excellent print quality.

  As a result of intensive studies to solve the above problems, the present inventor has made the natural frequency of the print area surrounded by the frame larger than the frequency generated in the print area when the carriage moves. Even when the carriage moves for printing and unnecessary vibration is transmitted to the droplet discharge head, the natural frequency (frequency) of the printing area is higher than the frequency generated in the printing area. The region is less likely to vibrate, and even if it vibrates, the vibration is attenuated faster. As a result, the region is less susceptible to unwanted vibrations and the distance between the droplet discharge head and the print medium can be kept constant. Therefore, the present inventors have found a new fact that the displacement of the printing position can be suppressed and printing can be performed with excellent printing quality even when the thickness of the mounted piezoelectric actuator is thin, and the present invention has been completed. .

That is, the carriage and the droplet discharge device of the present invention have the following configurations.
(1) A carriage including a substrate having a mounting surface of a droplet discharge head provided with a piezoelectric actuator, and a frame for fixing the droplet discharge head mounted on the mounting surface to the substrate, In a state where the droplet discharge head is mounted, the natural frequency of the print area of the droplet discharge head surrounded by the frame is greater than the frequency generated in the print area when the carriage moves for printing. A carriage characterized by that.
(2) A frame support that contacts the back surface of the print area on the piezoelectric actuator side of the droplet discharge head surrounded by the frame and connects at least two points of the frame is provided, and the frame support is on the piezoelectric actuator side. The carriage according to (1), wherein the carriage is adhered to the back surface of the printing area.
(3) The carriage according to (2), wherein the frame support has a cross shape.
(4) The carriage according to (2), wherein a plurality of the frame supports are formed.
(5) Conveying means for conveying the print medium in one direction, the carriage according to any one of (1) to (4), and a carriage that travels and scans the carriage in a direction orthogonal to the conveyance direction of the print medium. A droplet discharge device comprising: a transfer unit, and discharging droplets from a droplet discharge head mounted on the carriage.
(6) The droplet discharge device according to (5), wherein the droplet discharge device is a printer.

  According to the present invention, since the natural frequency of the print area surrounded by the frame is made larger than the frequency generated in the print area when the carriage moves, the carriage moves for printing and unnecessary vibration is generated. Is transmitted to the droplet discharge head, the print area is less likely to vibrate, and even if the vibration is vibrated, the vibration is attenuated more quickly. Since the distance from the printing medium can be kept constant, the displacement of the printing position can be suppressed, and an effect that printing can be performed with excellent printing quality even when the thickness of the mounted piezoelectric actuator is thin can be obtained. Moreover, even when the carriage is operated at a higher speed than in the prior art, the print quality can be kept constant, so that high-speed printing is possible, and it can be suitably used as a droplet discharge device, particularly a printer.

<Carriage>
Hereinafter, an embodiment of a carriage according to the present invention will be described in detail with reference to the drawings. 1A and 1B are schematic perspective views illustrating a carriage according to the present embodiment. FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. FIG. 3 is a plan view of FIG.

  As shown in FIGS. 1 to 3, the carriage 2 includes a substrate 10 having an attachment surface for the droplet discharge head 1 and a frame 7 for fixing the droplet discharge head 1 attached to the attachment surface to the substrate 10. It consists of and.

  For example, as illustrated in FIG. 9, the droplet discharge head 1 includes a flat plate-like flow path member 8 and a flat plate-like piezoelectric actuator 6. In the flat channel member 8, a plurality of ink pressurizing chambers 101 are arranged in parallel, and a partition wall 102 is formed as a wall that partitions the ink pressurizing chambers 101. A nozzle 109 for discharging the filled ink as an ink droplet is communicated with each ink pressurizing chamber 101 via a nozzle flow path.

  The piezoelectric actuator 6 includes a piezoelectric diaphragm 105, a common electrode 110, a piezoelectric ceramic layer 106, and an individual electrode 107. On the piezoelectric diaphragm 105, the common electrode 110, the piezoelectric ceramic layer 106, and the individual electrode 107 are arranged in this order. Laminated.

  The common electrode 110 and the individual electrode 107 constitute an electrode of the piezoelectric actuator 6, and a plurality of individual electrodes 107 are formed on the surface of the piezoelectric ceramic layer 106 in an independent state. Thereby, a plurality of piezoelectric elements 108 configured by sandwiching the piezoelectric ceramic layer 106 between the common electrode 110 and the individual electrode 107 are arranged on the piezoelectric diaphragm 105, and a drive voltage is applied between the common electrode 110 and the individual electrode 107. When applied, each piezoelectric element 108 is displaced.

  The flow path member 8 and the piezoelectric actuator 6 are joined using an adhesive or the like so that the piezoelectric vibration plate 105 is in contact with the space of the ink pressurizing chamber 101. More specifically, each piezoelectric element 108 is individually connected. The electrode 107 and each ink pressurizing chamber 101 are joined so as to correspond to each other.

  Further, as shown in FIG. 2, a flexible wiring 9 is connected to the upper surface of the individual electrode 107 of the piezoelectric actuator 6 so that a print signal is input from an external control device. An ink introduction tub (not shown) for introduction into the member 8 is installed on the flexible wiring 9.

  When a voltage is applied between the common electrode 110 and the predetermined individual electrode 107, the piezoelectric ceramic layer 106 immediately below the individual electrode 107 to which the voltage is applied is displaced, and the ink in the ink pressurizing chamber 101 is moved. The ink is ejected from the nozzle 109 under pressure.

  Here, as shown in FIG. 1B, a printing area of the droplet discharge head 1 is formed in the area where the piezoelectric actuator 6 is attached, and the frame 7 is placed on the flow path member 8 so as to surround the printing area. Glued. The frame 7 is for fixing the flow path member 8 to which the flat piezoelectric actuator 6 is bonded and fixed to the carriage 2.

  The material of the frame 7 is preferably high in rigidity so as not to cause unnecessary vibration, and examples thereof include metal members such as stainless steel, 42 alloy, and aluminum, and ceramic members such as alumina. Moreover, it is preferable to perform adhesion | attachment with the flame | frame 7 and the flow-path member 8 using resin-type adhesive agents, such as an epoxy type, for example.

  The substrate 10 has an attachment surface for attaching the droplet discharge head 1, and the droplet discharge head 1 is attached to the attachment surface via the frame 7. The substrate 10 is not particularly limited as long as the droplet discharge head 1 can be attached and functions as a carriage substrate. For example, an organic resin such as epoxy, stainless steel (SUS) is used. ) Or a metal such as a Ti alloy, and ceramics such as alumina.

  Here, in the carriage of the present invention, in the state where the droplet discharge head 1 is mounted, the natural frequency of the print area of the droplet discharge head 1 surrounded by the frame 7 moves the carriage 2 for printing. The relationship is greater than the frequency generated in the printing area. As a result, even if the carriage 2 moves for printing and unnecessary vibration is transmitted to the droplet discharge head 1, the printing area is less likely to vibrate, and the vibration is quickly attenuated even if vibrated.

  In order to establish the above relationship between the natural frequency of the print area and the frequency generated in the print area, it is applied to the back surface of the print area on the piezoelectric actuator 6 side in the droplet discharge head 1 surrounded by the frame 7. It is preferable to provide a frame support 7 a that is in contact with and connects at least two points of the frame 7. Furthermore, by adhering this frame support 7a to the back surface of the print area on the piezoelectric actuator 6 side, the natural frequency of the print area and the frequency generated in the print area can be in the above relationship. . It is preferable that the adhesion is firmly performed using an adhesive or the like.

  Specifically, the frame support 7 a according to the present embodiment is bonded so as to contact the back surface of the printing region so as to straddle the central portion of the piezoelectric actuator 6 and to connect the two points of the frame 7. Further, the frame 7a is firmly bonded to the back surface of the printing area on the piezoelectric actuator 6 side using an adhesive or the like. As described above, by disposing the frame support 7a, the printing area is less likely to vibrate, and even if it vibrates, the damping of the vibration is accelerated. Furthermore, since the area of the printing area is narrowed, the natural frequency of the printing area can be set higher. As a result, the printing area is less affected by unnecessary vibration, and the liquid droplet ejection head 1 and the printing medium are not affected. The interval is kept constant, the deviation of the printing position can be suppressed, and the predetermined printing quality can be maintained.

  As the material of the frame support 7a, the same material as that of the frame 7 can be exemplified, and the adhesion of the frame support 7a is similar to the adhesive exemplified in the adhesion between the frame 7 and the flow path member 8. Although it can illustrate, it is not limited to these. The width and thickness of the frame support 7a may be arbitrarily selected within a range that does not hinder the displacement of the piezoelectric actuator 6. Specifically, it is desirable that the width of the frame support 7a be approximately equal to or more than half the width of the frame 7. Further, the thickness of the frame support 7a is thinner than the thickness of the frame 7 by the piezoelectric actuator 6, that is, the upper surface of the frame 7 and the upper surface of the frame support 7a are substantially the same height. Is desirable. As a result, the droplet discharge head 1 and the carriage 2 are more firmly fixed via the frame 7.

  The frame support according to the present invention is not limited to the frame support 7a described in the above embodiment, but is applied to the back surface of the print area on the piezoelectric actuator 6 side in the droplet discharge head 1 surrounded by the frame 7. It suffices to connect at least two points of the frame 7 and to be firmly bonded to the back surface of the printing area on the piezoelectric actuator 6 side using an adhesive or the like. Examples of such a frame support include those shown in FIGS. 4 to 6, the same or equivalent parts as those in FIGS. 1 to 3 described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 4 is a plan view showing another frame support according to the present invention. As shown in the figure, the frame support 7b is in contact with the back surface of the printing area so as to straddle the central portion of the piezoelectric actuator 6 in a direction orthogonal to the frame support 7a described above, and The two points are connected and firmly adhered to the back surface of the print area on the piezoelectric actuator 6 side using an adhesive or the like. Even with such a configuration, the print area is less susceptible to unwanted vibration.

  FIG. 5 is a plan view showing still another frame support according to the present invention. As shown in the figure, in this embodiment, the two frame supports 7c are arranged in parallel so as to contact the back surface of the print area of the piezoelectric actuator 6 and to connect the two points of the frame 7. Furthermore, it is firmly bonded to the back surface of the printing area on the piezoelectric actuator 6 side using an adhesive or the like. Thus, it is preferable to form a plurality of frame supports because the print area is less susceptible to unwanted vibration. The number of frame supports formed is not limited to two, but may be arbitrarily selected within the range of about 2 to 4 and within the range that does not hinder the displacement of the piezoelectric actuator 6.

  FIG. 6 is a plan view showing still another frame support according to the present invention. As shown in the figure, the shape of the frame support 7d is a cross shape. Even with such a configuration, the print area is less susceptible to unwanted vibration.

<Droplet ejection device>
Next, an embodiment of a droplet discharge apparatus including a carriage according to the present invention will be described in detail with reference to the drawings. FIG. 7 is a schematic view showing a droplet discharge device according to this embodiment. As shown in FIG. 7, in the droplet discharge device according to the present invention, a droplet discharge head 1 is attached to a carriage 2 that is transported along a carriage shaft 3 by a carriage motor (not shown). It is configured to reciprocate in the scanning direction (X direction shown in FIG. 7). Here, the carriage 2, the carriage shaft 3, and the carriage motor constitute a carriage transfer unit that relatively moves the droplet discharge head 1 and the recording medium 4.

  On the other hand, the recording medium 4 such as paper is sandwiched between a pair of transport rollers 5 and is transported by the transport rollers 5 in the sub-scanning direction (Y direction shown in FIG. 7) perpendicular to the main scanning direction. ing. Then, the carriage 2 moves to a predetermined position of the recording medium 4, and the piezoelectric actuator 6 of the droplet discharge head 1 attached to the carriage 2 is vibrated to pressurize the ink and eject the ink from the nozzle toward the recording medium 4. An ink droplet is landed on the recording medium 4 to form an image or the like.

  At this time, the droplet discharge head 1 is mounted on the mounting surface of the substrate 10 constituting the carriage 2 via the frame 7 and the frame supports 7a to 7d. The frequency generated in the area has a predetermined relationship, and even if the carriage 2 moves for printing and unnecessary vibration is transmitted to the droplet discharge head 1, the printing area is not easily affected by the unnecessary vibration. Therefore, the distance between the droplet discharge head 1 and the print medium 4 is kept constant, and the shift of the print position is suppressed.

  Such a droplet discharge apparatus according to the present invention can maintain a constant print quality even when the carriage is operated at a higher speed than in the prior art, so that high-speed printing is possible, especially a printer (inkjet printer). Can be suitably used.

  In the above embodiment, the piezoelectric actuator 6 is described as being composed of a single piezoelectric actuator. However, the present invention is not limited to this, and the present invention is also applicable to a piezoelectric actuator divided into a plurality of parts. Is possible. FIG. 8 is a plan view showing a droplet discharge head equipped with this piezoelectric actuator. As shown in the figure, in this case, the piezoelectric actuators 6a divided into a plurality are firmly bonded to the flow path member 8, respectively, and a printing area is formed in the area where each piezoelectric actuator 6a is attached. It is important that the frame 7 is firmly bonded on the flow path member 8 so as to surround each printing area.

  With this configuration, the area of the piezoelectric actuator is reduced, so that even if the thickness of the piezoelectric actuator is thin, each print area is less likely to be affected by unnecessary vibration. As a result, the natural frequency of each print area surrounded by the frame 7 becomes larger than the frequency generated in the print area when the carriage moves for printing, and the above-described effects of the present invention can be obtained. it can.

(A) And (b) is a schematic perspective view which shows the carriage concerning one Embodiment of this invention. It is A-A 'line sectional drawing of FIG.1 (b). It is a top view of FIG.1 (b). It is a top view which shows the other frame support body concerning this invention. It is a top view which shows the other flame | frame support body concerning this invention. It is a top view which shows the other flame | frame support body concerning this invention. It is the schematic which shows the droplet discharge apparatus concerning one Embodiment of this invention. It is a top view which shows the droplet discharge head provided with the other piezoelectric actuator concerning this invention. It is a schematic sectional drawing which shows a general droplet discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 2 Carriage 3 Carriage shaft 4 Recording medium 6 Piezoelectric actuator 7 Frame 7a, 7b, 7c, 7d Frame support body 8 Flow path member 9 Flexible wiring 10 Substrate 101 Ink pressurization chamber 102 Partition 105 Piezoelectric diaphragm 106 Piezoelectric Ceramic layer 107 Individual electrode 108 Piezoelectric element 109 Nozzle 110 Common electrode

Claims (6)

A carriage including a substrate having a mounting surface of a droplet discharge head provided with a piezoelectric actuator, and a frame for fixing the droplet discharge head attached to the mounting surface to the substrate;
In a state where the droplet discharge head is mounted, the natural frequency of the print area of the droplet discharge head surrounded by the frame is greater than the frequency generated in the print area when the carriage moves for printing. A carriage characterized by that.   A frame support body that contacts the back surface of the print area on the piezoelectric actuator side of the droplet discharge head surrounded by the frame and connects at least two points of the frame; and the frame support body is a print area on the piezoelectric actuator side The carriage according to claim 1, which is adhered to the back surface of the carriage.   The carriage according to claim 2, wherein the frame support has a cross shape.   The carriage according to claim 2, wherein a plurality of the frame supports are formed.   A transport unit that transports the print medium in one direction; a carriage according to any one of claims 1 to 4; and a carriage transfer unit that travels and scans the carriage in a direction orthogonal to the transport direction of the print medium. A droplet discharge apparatus that discharges droplets from a droplet discharge head mounted on the carriage. The droplet discharge device according to claim 5, wherein the droplet discharge device is a printer.

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