JP2006327062A - Liquid ejection head and liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head and a liquid ejector, which enable one surface (nozzle surface) with a formed nozzle opening to be moved with high responsiveness and high energy efficiency. <P>SOLUTION: An ejection unit 40, which is equipped with the nozzle surface 13 with the formed nozzle and a piezoelectric element 142 as a pressure generating means, is connected to a base unit 20, which is formed in a relatively large size so as to be fixed to a carriage and connected to an ink cartridge, in such a manner as to be movable via an actuator. Communication ports 27a-27d, which are formed on the sides of the other ends of channels 26a-26d communicating with ink introducing needles 24a-24d for introducing ink, and communication ports 41a-41d, which are formed on the sides of the other ends of the channels communicating with the nozzle, are flexibly connected together via an easily deformable communication passage member, so that a series of supply channels can be formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid discharge apparatus and a liquid discharge head that perform drawing by discharging a liquid, such as an ink jet recording apparatus, a display manufacturing apparatus, an electrode forming apparatus, or a biochip manufacturing apparatus.

  Conventionally, an ink jet printer suitable for printing on paper is known as a liquid ejecting apparatus, and in general, a liquid ejecting head that ejects liquid (ink) is moved so as to face the transport surface of the paper. The configuration is arranged as possible. Then, the paper is transported in one direction (sub-scanning) and the liquid discharge head is reciprocated (main scan) perpendicular to the transport direction, and the paper is discharged from the nozzles formed on one surface (nozzle surface) of the liquid discharge head. Ink droplets are ejected to form an image.

  Since the ejected ink droplets have a velocity component in the scanning direction of the liquid ejection head and fly through the gap between the nozzle surface and the paper surface and land on the paper surface, in order to increase the landing position accuracy, the gap The distance (PG) needs to be kept constant. However, the paper surface may show a waved state (cockling) due to moisture absorption from the landed ink, and this may cause the PG to vary within the paper surface, leading to a reduction in image quality due to landing position deviation. Accordingly, in view of such circumstances, there has been proposed a liquid ejection apparatus configured to keep PG constant by swinging the liquid ejection apparatus in a direction perpendicular to the sheet surface while sensing PG during main scanning. (Patent Document 1).

JP 11-320855 A

  However, in the above-described liquid ejecting apparatus, the liquid ejecting head is swung in a state where an ink cartridge for containing ink is mounted. Therefore, a large power is required for the rocking, and the power mechanism itself is large. It will become. Moreover, since the inertia of the rocking part is large, high responsiveness cannot be expected.

  The present invention has been made to solve the above-described problems, and a liquid discharge head and a liquid that can move one surface (nozzle surface) on which nozzle openings are formed with high responsiveness and high energy efficiency. It aims at providing a discharge device.

  A liquid discharge head of the present invention includes a base unit including an introduction port for introducing a liquid, and a first communication port that is an opening formed on the other end side of a flow path communicating with the introduction port; A nozzle formed with an opening on one surface, pressure generating means capable of pressurizing the liquid filled in the nozzle, and an opening formed on the other end side of the flow path communicating with the nozzle A discharge unit having a second communication port, and the first communication port in the base unit and the second communication port in the discharge unit are flexibly connected to form a continuous flow path. A communication path member and movable means for moving the discharge unit relative to the base unit are provided.

  In the liquid discharge head of the present invention, a base unit that needs to be formed to be large to some extent for connection with a liquid supply means and fixation to a main body, and a discharge unit that can be formed in a compact manner form a series of supply flow paths. It is mechanically connected while securing, and only the discharge unit can be moved by the movable means. Thus, since the mass of the movable part is small, the responsiveness and energy efficiency of movement of one surface (nozzle surface) on which the nozzle openings are formed are excellent.

Preferably, in the liquid discharge head, the movable means is configured such that one surface of the discharge unit moves with a degree of freedom of rotation or translation.
According to the liquid ejection head of the present invention, since the movable means is configured so that the nozzle surface moves with a degree of freedom of rotation and translation, the nozzle surface, the ejection object, and the like are mounted in the liquid ejection apparatus. The distance and the parallelism can be corrected.

Preferably, in the liquid discharge head, the communication path member includes a flexible member that can be easily deformed.
According to the liquid discharge head of the present invention, the first communication port and the second communication port can be flexibly connected without generating a large load by the communication path member including the soft member.

Preferably, in the liquid ejection head, the movable unit includes an electromechanical element capable of controlling a displacement amount by an electric signal.
According to the liquid discharge head of the present invention, the movement control of the discharge unit can be performed with high responsiveness by the electric signal.

The liquid discharge apparatus according to the present invention includes the liquid discharge head.
The liquid discharge apparatus according to the present invention includes a base unit that needs to be formed to be somewhat large for connection to a liquid supply means and fixing to a main body, and a discharge unit that can be formed relatively compactly. A liquid discharge head that is mechanically connected while securing a path and can move only the discharge unit by a movable means is mounted. Thus, since the mass of the movable part is small, the nozzle surface movement responsiveness and energy efficiency are excellent.

Preferably, in the liquid ejection device, the liquid ejection head is held in the base unit so that one surface of the ejection unit faces an ejection target, and the liquid ejection head is scanned in a certain direction. And a PG control means for driving the movable means so as to keep a constant gap distance: PG between one surface of the ejection unit and the ejection object during scanning of the liquid ejection head. To do.
According to the liquid ejection apparatus of the present invention, the liquid can be ejected onto the ejection object while keeping the PG constant regardless of the surface state of the ejection object, so that an image is formed with high landing accuracy. be able to.

Preferably, in the liquid ejection apparatus, the PG control unit includes a detection unit for detecting a undulation of a surface of the ejection target that faces one surface of the ejection unit.
More preferably, the detection means is an optical sensor.
According to the liquid ejection devices of these inventions, the PG control means can be configured with a relatively simple configuration by the detection means such as an optical sensor.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
Note that the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

  First, the overall configuration of the liquid ejection apparatus will be described with reference to FIG. FIG. 1 is a schematic perspective view showing an example of a liquid ejection apparatus according to the present invention.

  In FIG. 1, a printer 1 as a liquid ejection apparatus is an apparatus that draws an image or the like by ejecting ink as a liquid onto a sheet 2 as an ejection target. The printer 1 includes a liquid ejection head 3 that ejects ink, a carriage 4 that mounts the liquid ejection head 3, a scanning mechanism 5 that reciprocates the carriage 4, and a sheet 2 that is conveyed in a direction orthogonal to the scanning direction of the carriage 4. And a maintenance unit 12 that performs maintenance of the liquid discharge head 3.

  As ink ejected from the liquid ejection head 3, for example, four colors of black, magenta, cyan, and yellow are used, and are accommodated in ink cartridges 7 a to 7 d mounted on the carriage 4, respectively. . At the bottom of each of the ink cartridges 7a to 7d, a lead-out portion (not shown) for leading out the ink is provided, which is coupled to the ink introduction needles 24a to 24d (see FIG. 2) provided on the liquid ejection head 3. Ink is supplied to the liquid ejection head 3.

  The scanning mechanism 5 as scanning means includes a timing belt 8 coupled to the carriage 4, a motor 9 that drives the timing belt 8, and a guide rod 10 that forms a guide shaft of the carriage 4. The carriage 4 is driven by a motor 9 via a timing belt 8 and can reciprocate along a guide rod 10.

  The liquid ejection head 3 includes a carriage 4 so that the nozzle surface 13 and the paper surface 2a, which are one surface on which the openings of the nozzles 42a to 42d (see FIG. 3) are formed, face each other with a predetermined gap distance PG. It is mounted on. Thus, the liquid ejection head 3 reciprocates (scans) on the paper 2 and ejects ink droplets from the nozzle surface 13 at a timing synchronized with the scanning and the conveyance of the paper 2 to provide a desired surface on the paper surface 2a. An image or the like can be formed.

  An optical sensor 16 as a detection unit is attached to the carriage 4 so as to face the paper surface 2a. The printer 1 detects the undulation of the paper surface 2a by measuring the distance between the light receiving surface of the optical sensor 16 and the paper surface 2a. Although only one optical sensor 16 is shown in the drawing, actually, the optical sensor 16 is provided on both sides of the liquid ejection head 3 in correspondence with the forward path of the carriage 4.

  The main body of the printer 1 and the carriage 4 are electrically connected by a flexible cable 11. The flexible cable 11 transmits electrical signals related to ejection control and detection control by the optical sensor 16, electrical signals related to movement control of the nozzle surface 13 described later, and the like.

  The maintenance unit 12 includes a cap member 15 that can be sealed around a certain region of the nozzle surface 13 of the liquid ejection head 3. The cap member 15 covers the nozzle surface 13 to protect the nozzles 42a to 42d (see FIG. 3) from dust and dryness, and so-called recovery operation for forcibly discharging ink from the nozzles 42a to 42d. Also used for.

  The maintenance unit 12 also has a wiper blade 14 that is a plate-like member formed of rubber or the like. The wiper blade 14 is used for wiping off ink adhering to the nozzle surface 13 in the recovery operation.

  Next, the configuration of the liquid ejection head will be described with reference to FIGS. 2, 3, 4, and 5. FIG. 2 is an exploded perspective view showing a schematic configuration of the liquid discharge head. FIG. 3 is a plan view showing the nozzle surface of the liquid ejection head. FIG. 4 is a partially broken perspective view showing an example of the main structure of the discharge unit. FIG. 5 is a cross-sectional view showing a connection structure between the base unit and the discharge unit.

  In FIG. 2, the liquid discharge head 3 is configured by attaching a discharge unit 40 to a lower base portion 21 b of the base unit 20. The base unit 20 is a relatively large assembly part mainly composed of a resin-molded base 21, and the discharge unit 40 is a relatively small and flat assembly part in which a fine flow path including a nozzle is formed.

  The base 21a of the base 21 is formed in a substantially rectangular parallelepiped shape with a certain size so that the ink cartridges 7a to 7d can be placed side by side (see FIG. 1), and is formed on the carriage 4 (see FIG. 1). On the other hand, positioning protrusions and recesses (not shown) are formed so that they can be fixed. Further, the upper base portion 21a is also provided with a connector 28 serving as a connection terminal with the flexible cable 11 (see FIG. 1), a guide rib 23 for holding a lead-out portion (not shown) of the ink cartridges 7a to 7d, and the like. ing. The ink introduction needles 24a to 24d attached to the upper base portion 21a are hollow needle-shaped members, each having an introduction port 25 for introducing ink, and communication channels 26a to 26d formed in the base 21. Each communicates.

  In the state where the liquid ejection head 3 is mounted on the carriage 4 (see FIG. 1), the lower base portion 21b formed to protrude to the side opposite to the side on which the ink cartridges 7a to 7d of the upper base portion 21a are mounted. This is a portion facing the sheet 2 (see FIG. 1). On the bottom surface 21c of the lower base portion 21b, communication ports 27a to 27d are formed as first communication ports provided as openings on the other end side of the communication channels 26a to 26d.

  2 and 3, the nozzle surface 13 of the discharge unit 40 is formed with openings of nozzles 42a to 42d corresponding to the respective colors of black, magenta, cyan, and yellow. Further, a communication port 41a as a second communication port provided as an opening on the other end side of the flow path communicating with each of the nozzles 42a to 42d on the upper surface 40a which is a surface facing the base unit 20 of the discharge unit 40. -41d are formed. The nozzles 42a and 42b and the nozzles 42c and 42d constitute two nozzle rows extending in a direction orthogonal to the scanning direction (Y-axis direction), and both nozzle rows are arranged at a certain distance. It has a configuration.

  2 and 4, the discharge unit 40 includes a nozzle plate 144 formed of a metal plate or the like, a flow path unit 147 formed integrally with ceramic, and a piezoelectric element formed on the canopy 143 of the flow path unit 147. And an element 142.

  The flow path unit 147 includes a plurality of pressure chambers (cavities) 140 formed by being partitioned by a partition wall 141. Each pressure chamber 140 communicates with the nozzle 42 a and also communicates with a reservoir 145 that is a common chamber formed for each ink type via the supply port 146. A through hole for introducing ink into the reservoir 145 is formed immediately above the reservoir 145 in the canopy 143 of the flow path unit 147, and the opening of the through hole corresponds to the communication port 41a shown in FIG. Is. Thus, the black ink supplied from the communication port 41 a is filled up to the nozzle 42 a via the reservoir 145 and the pressure chamber 140. The same applies to the flow path configuration including the nozzles 42b to 42d (see FIG. 3) corresponding to magenta, cyan, and yellow inks.

  The canopy portion 143 of the flow path unit 147 is formed thin so that it can be easily bent, and the pressure chambers are deformed by deformation of the piezoelectric element 142 as pressure generating means formed immediately above each pressure chamber 140. The volume of 140 and the internal pressure can be changed. A flexible drive circuit wiring (not shown) is electrically connected to the piezoelectric element 142 (one end is connected to a terminal of the connector 28), and driving for each piezoelectric element 142 via the drive circuit wiring is performed. The ink droplet 150 can be discharged from the desired nozzle 42a by the control.

  In addition, the structure of the discharge unit 40 mentioned above is an example to the last, and the structure of the discharge unit in this invention is not limited to what was mentioned above. For example, the nozzle rows can be composed of one to four rows, or a so-called thermal configuration in which ink is heated to generate pressure.

  2 and 5, the base unit 20 and the discharge unit 40 are connected via a pair of actuators 51 and 52 that constitute movable means so that the bottom surface 21 c of the base unit 20 and the top surface 40 a of the discharge unit 40 face each other. Connected mechanically. Further, the communication ports 27 a to 27 d of the base unit 20 and the communication ports 41 a to 41 d of the discharge unit 40 are respectively connected via the communication path member 50.

  The communication passage member 50 is an easily deformable member, for example, a material in which a soft member having a small rubber hardness (preferably 10 ° Hs or less) such as a silicone or urethane is dispersed or dissolved in an adhesive solvent. After applying in a ring shape, it is cured to form. As a modification, a soft member formed in an O-ring shape may be prepared and bonded to the bottom surface 21c of the base unit 20 and the top surface 40a of the discharge unit 40 via an adhesive.

  The actuators 51 and 52 as electromechanical elements can control the displacement amount of the movable parts 51a and 52a by an electric signal. For example, a piezoelectric type, an electromagnetic type, an SMA (shape memory alloy) type, or the like is used. Can do. Preferably, the one having a response frequency of 50 Hz or more and a stroke of 0.2 mm or more in a state connected to the discharge unit 40 is used.

  The pair of actuators 51 and 52 are connected to the vicinity of the outer edge of the discharge unit 40 at the movable portions 51a and 52a, and can be driven independently. Thus, the nozzle surface 13 is moved with the degree of freedom of translation indicated by the arrow A or the rotation indicated by the arrow B, and the gap distance between the nozzle surface 13 and the paper surface 2a depending on the undulation of the paper surface 2a and the dimensional variation of the parts. : PG or parallelism can be corrected.

  As can be seen from the above description, the discharge unit 40 is a collective component configured to discharge ink from the nozzle surface 13 as a main function, and the base unit 20 includes ink cartridges 7a to 7d (see FIG. 1). It is a collective component configured mainly for connection and fixing to the carriage 4 (see FIG. 1). As described above, the liquid discharge head 3 is unitized for each function, and each unit is configured to be relatively movable, so that the movable part can be reduced in size and weight, and has excellent responsiveness and energy efficiency. The nozzle surface 13 can be moved at this point.

  Next, the electrical configuration of the printer and the PG constant value control during scanning will be described with reference to FIGS. FIG. 6 is a block diagram showing the electrical configuration of the printer.

  The printer 1 includes a print controller 61 and a nozzle surface controller 62 each including a CPU, a memory, an amplifier circuit, and the like in the control unit 60. The print controller 61 is a part in charge of the main control related to the printing operation, and drives the scanning mechanism 5 to scan the carriage 4 and controls the driving of the piezoelectric element 142 in synchronization with the scanning. The nozzle surface controller 62 is a part in charge of constant value control of the gap distance: PG (see FIG. 5) between the nozzle surface 13 and the paper surface 2a, and acquires information on the undulation of the paper surface 2a by the optical sensor 16. The PG is corrected by driving the actuators 51 and 52. That is, the nozzle surface controller 62 and the optical sensor 16 constitute PG control means in the present invention.

  The constant value control of PG is performed at a constant scanning distance interval (for example, an interval of 2 to 3 mm) in synchronization with a scanning timing signal transmitted from the print controller 61 to the nozzle surface controller 62. That is, the actuators 51 and 52 are driven at an appropriate timing so as to detect the undulation at each reference position of the paper surface 2a by the optical sensor 16 scanned together with the nozzle surface 13, and to compensate for the undulation difference between the reference positions. The PG is corrected so as to keep the PG constant. Since the correction of PG is performed with high responsiveness by the movement of the small and light discharge unit 40, the above-described constant value control of PG is performed with high accuracy, and image quality deterioration due to landing position deviation is preferably prevented.

The present invention is not limited to the above-described embodiment.
For example, the liquid ejection device according to the present invention is not limited to a so-called ink jet printer for paper printing, and a functional liquid containing various functional materials such as a light emitting material and a conductive material is applied to an industrial substrate. Industrial devices such as a display body manufacturing apparatus and an electrode forming apparatus that are configured to be discharged are also included.
The movable means according to the present invention can also be configured using one or three or more actuators.
Moreover, each structure of each embodiment can combine these suitably, can be abbreviate | omitted, or can be combined with the other structure which is not illustrated.

1 is a schematic perspective view illustrating an example of a liquid ejection apparatus according to the present invention. FIG. 3 is an exploded perspective view showing a schematic configuration of a liquid discharge head. FIG. 3 is a plan view showing a nozzle surface of a liquid discharge head. The perspective view of a partially broken part which shows an example of the principal part structure of a discharge unit. Sectional drawing which shows the connection structure of a base unit and a discharge unit. FIG. 2 is a block diagram illustrating an electrical configuration of the printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid discharge apparatus, 2 ... Paper as discharge target object, 2a ... Paper surface, 3 ... Liquid discharge head, 4 ... Carriage, 5 ... Scanning mechanism as scanning means, 7a-7d ... Ink cartridge, 13 ... Nozzle surface as one surface on which nozzle openings are formed, 16 ... Optical sensor as detection means constituting PG control means, 20 ... Base unit, 21 ... Base, 21a ... Upper base part, 21b ... Lower base part, 21c ... bottom surface, 24a to 24d ... ink introduction needle, 25 ... introduction port, 26a to 26d ... flow path, 27a to 27d ... communication port as the first communication port, 40 ... discharge unit, 40a ... top surface, 41a to 41d ... Communication port as second communication port, 42a to 42d ... nozzle, 50 ... communication path member, 51, 52 ... actuator as electromechanical element constituting movable means, 60 Control unit 61... Print controller 62. Nozzle surface controller constituting PG control means 140. Pressure chamber 141 141 partition wall 142. Piezoelectric element as pressure generating means 143 Canopy part 144 144 Nozzle plate 145 ... reservoir, 146 ... supply port, 147 ... flow path unit.

Claims (8)

A base unit comprising: an introduction port for introducing a liquid; and a first communication port which is an opening formed on the other end side of the flow path communicating with the introduction port;
A nozzle formed with an opening on one surface, pressure generating means capable of pressurizing the liquid filled in the nozzle, and an opening formed on the other end side of the flow path communicating with the nozzle A second communication port, and a discharge unit comprising:
A communication path member that flexibly connects the first communication port in the base unit and the second communication port in the discharge unit to form a continuous flow path;
A liquid discharge head comprising: a movable unit that moves the discharge unit relative to the base unit.   The liquid discharge head according to claim 1, wherein the movable unit is configured such that one surface of the discharge unit moves with a degree of freedom of rotation or translation.   The liquid ejection head according to claim 1, wherein the communication path member includes a soft member that can be easily deformed.   The liquid ejecting head according to claim 1, wherein the movable unit includes an electromechanical element capable of controlling a displacement amount by an electric signal.   A liquid ejecting apparatus equipped with the liquid ejecting head according to claim 1. Scanning means for holding the liquid discharge head in the base unit so that one surface of the discharge unit faces an object to be discharged, and scanning the liquid discharge head in a certain direction;
And PG control means for driving the movable means so as to keep a gap distance: PG between one surface of the ejection unit and the ejection target object constant during scanning of the liquid ejection head. Item 6. The liquid ejection device according to Item 5.   The liquid ejecting apparatus according to claim 6, wherein the PG control unit includes a detecting unit configured to detect a undulation of a surface of the discharge target that faces one surface of the discharge unit. The liquid ejecting apparatus according to claim 7, wherein the detection unit is an optical sensor.

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