JP2018167497A - Liquid discharge device - Google Patents

Abstract

To efficiently perform stirring operation for preventing deterioration in recording quality due to such as settlement of pigment particles.SOLUTION: A liquid discharge device includes: a liquid discharge head having a discharge port for discharging liquid to a recording medium; first guiding means for guiding the liquid discharge head in a first direction so as to separate from and come close to the recording medium; and second guiding means for guiding the liquid discharge head in a second direction different from the first direction with guide by the first guiding means to stir liquid in the liquid discharge head.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a recording apparatus that performs recording by discharging a liquid, for example, an inkjet recording apparatus that discharges ink.

  In an inkjet recording apparatus (hereinafter also simply referred to as a recording apparatus) for recording an image by ejecting ink, ink is ejected from an ejection port of an inkjet recording head (hereinafter also simply referred to as a recording head), and recording paper or the like Land on the recording medium.

  Examples of the ink used for the recording head include a dye ink in which a dye is dissolved in a solvent and a pigment ink in which a pigment is dispersed in a solvent. In particular, the pigment ink is superior in water resistance and weather resistance than the dye ink. However, for example, when the pigment ink is left standing for a long time, the pigment particles settle, and in the lower layer where the ink is accumulated, the pigment particle concentration is a layer having a high and transient color (hereinafter also referred to as a sedimented ink), and the upper layer is ink. The phenomenon that the density becomes low and the color becomes a thin layer occurs.

  Therefore, for example, it is conceivable to apply the technique disclosed in Patent Document 1 and stir the precipitated ink in the recording head by moving the carriage including the recording head up and down within a predetermined range.

JP 2008-188898 A

  However, if the recording apparatus is left standing for a long period of time only by moving up and down, the ink may not be stirred well. As a result, the recording quality may be deteriorated due to unevenness of the liquid viscosity and density due to the precipitated ink. In addition, if it is attempted to remove the precipitated ink using only a recovery operation such as preliminary ejection, ink consumption may increase if ink is ejected more than necessary.

  Accordingly, an object of the present invention is to prevent a decrease in recording quality due to a sedimented ink or the like.

  A liquid ejection head having an ejection port for ejecting liquid to the recording medium, a first guiding means for guiding the liquid ejection head in a first direction so as to be separated from and close to the recording medium, and a liquid ejection And a second guide means for guiding the liquid discharge head in a second direction different from the first direction in accordance with the guidance by the first guide means for stirring the liquid in the head. To do.

  According to the present invention, it is possible to prevent a decrease in recording quality due to a sedimented ink or the like.

It is explanatory drawing of the conceptual structural example of the recording device which concerns on this embodiment of this invention. FIG. 2 is a block diagram of a control system of the recording apparatus in FIG. 1. FIG. 2 is a schematic perspective view of an engine unit of the recording apparatus according to the embodiment of the invention. FIG. 4 is a schematic perspective view of an engine frame in the engine unit of FIG. 3. FIG. 5 is a VV cross-sectional view of the head unit of FIG. 3. It is a perspective view of the head unit with which an engine unit is equipped. It is a VII arrow line view of the head unit of FIG. It is a VIII arrow line view of the head unit of FIG. FIG. 7 is a IX arrow view of the head unit of FIG. 6. It is explanatory drawing of the slide bearing with which a head unit is equipped. It is explanatory drawing of a slide bearing and a guide rail. 3 is a flowchart according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The recording apparatus of this embodiment is an example in which the present invention is applied to a full-line type inkjet recording apparatus.

  FIG. 1 is an explanatory diagram of a conceptual configuration example of a recording apparatus 10 according to the present embodiment. The recording device 10 is connected to a host device 12 such as a personal computer, and image information and the like are sent from the host device 12 to the recording device 10. In the present embodiment, full-color recording is performed on the recording medium P, which is a roll paper in the present embodiment, as the recording head 22. For this purpose, recording heads 22Bk, 22C, 22M, and 22Y for ejecting black (Bk), cyan (C), magenta (M), and yellow (Y) inks are provided. These are juxtaposed along the medium transport direction A. The recording heads 22Bk, 22C, 22M, and 22Y are supplied with ink of each corresponding color from an ink tank 28 described later. Note that the number of colors, that is, the number of recording heads, can be arbitrarily determined. In particular, when it is not necessary to distinguish between the recording heads, the following may be referred to simply as “recording head 22”. .

  Furthermore, the recording head 22 is configured to eject corresponding ink from a plurality of ejection ports using ejection energy generating elements such as electrothermal conversion elements (heaters) and piezoelectric elements. In the case of using an electrothermal conversion element, the ink can be foamed by the heat generation, and the ink can be ejected from the ejection port using the foaming energy. These discharge ports are arranged in a direction that intersects the medium conveyance direction A, in the case of the present embodiment, a direction that is orthogonal. These recording heads 22 are in the form of so-called long line heads, and the length of the recording head 22 or the ejection port array range of this embodiment is the maximum width of the recording medium that can be recorded in the recording apparatus 10. It is slightly longer than (the length in the direction orthogonal to the paper surface of FIG. 1). The recording head 22 is positioned at a predetermined recording position during the image recording operation.

  In order to execute the recovery process of the recording head 22, a recovery unit 400 is incorporated in the recording apparatus 10. The recovery unit 400 includes a capping mechanism 50 for removing ink from a discharge port formation surface (hereinafter also referred to as a discharge port formation surface) in the recording head 22. The capping mechanism 50 is provided so as to face the ejection ports of the respective recording heads 22Bk, 22C, 22M, and 22Y. The capping mechanism 50 includes a wiper for wiping the discharge port forming surface, a wiper holding member for holding the wiper, an ink removing member for removing ink adhering to the wiper, and a cap that is in close contact with the discharge port forming surface. Is provided.

  The recording medium P is supplied from the supply unit 24 and is transported in the medium transport direction A by the transport mechanism 26 incorporated in the recording apparatus 10. The transport mechanism 26 includes a transport belt 26a for placing and transporting the recording medium P, a transport motor 26b for rotating the transport belt 26a, and a roller 26c for applying tension to the transport belt 26a. The conveyance mechanism 26 may be configured to convey the recording medium P using a conveyance roller, or may constitute a unitized conveyance unit. In a specific configuration example described later, the transport mechanism 26 includes a supply unit 24 and is configured as a transport unit that transports the recording medium P using a transport roller.

  When an image is recorded on the recording medium P, after the recording start position on the recording medium P being conveyed reaches below the recording head 22Bk, a plurality of discharges in the recording head 22Bk are based on the recording data (image information). Black ink is selectively ejected from the outlet. Similarly, each color ink is ejected in the order of the recording head 22C, the recording head 22M, and the recording head 22Y to record a color image on the recording medium P. The recording apparatus 10 includes an ink tank 28 (28Bk, 28C, 28M, 28Y) that supplies ink to each recording head 22 (22Bk, 22C, 22M, 22Y). Further, the recording apparatus 10 includes various pumps for performing ink supply operation and recovery operation with respect to the recording head 22.

  FIG. 2 is a block diagram of the control system of the recording apparatus 10. Information such as recording data and commands transmitted from the host device 12 is received by the CPU 100 via the interface controller 102. The CPU 100 is responsible for overall control of the recording apparatus 10 such as reception of recording data, recording operation, and handling of the recording medium P (including control corresponding to the lifting / lowering operation of the recording head 22, which will be described later). It is a processing device. After analyzing the received command, the CPU 100 renders image data of each color component of the recording data by developing a bitmap on the image memory 106. The CPU 100 is connected to various sensors.

  When recording an image, first, the capping motor 122 and the head lifting / lowering motor 118 are driven and controlled via the output port 114 and the motor drive unit 116, and the respective recording heads 22 are separated from the corresponding capping mechanism 50 for recording. Move to position. The capping motor 122 is a motor for moving the capping mechanism 50 in the directions of arrows B1 and B2 in FIG. 1, and the head elevating motor 118 is for elevating the recording head 22 in the directions of arrows C1 and C2 in FIG. Motor. Thereafter, a roll motor (not shown) for feeding the recording medium P and a transport motor 26b for transporting the recording medium P at a constant speed are driven and controlled via the output port 114 and the motor drive unit 116. The recording medium P is transported in the medium transport direction A. The timing (recording timing) at which ink starts to be ejected to the recording medium P conveyed at a constant speed is determined based on the detection timing of the leading edge of the recording medium P by a leading edge detection sensor (not shown). The CPU 100 sequentially reads the recording data corresponding to each ink color from the image memory 106 in synchronization with the conveyance of the recording medium P, and reads the read data via the recording head control circuit 112 to the corresponding recording head 22Bk, Transfer to 22C, 22M, 22Y.

  The CPU 100 executes processing based on the processing program stored in the program ROM 104. The program ROM 104 stores processing programs and tables corresponding to the control flow. The work RAM 108 is used as a working memory. The CPU 100 drives and controls the pump motor 124 via the output port 114 and the motor driving unit 116 during the cleaning operation and the recovery operation of the respective recording heads 22 so as to pressurize and suck ink.

  FIG. 3 is a perspective view of an engine unit 200 incorporated in the recording apparatus 10. The engine unit 200 includes a head unit 300, a recovery unit 400, and a pump unit 500 in a resin engine frame 20. The configuration is summarized. FIG. 4 is a perspective view of the engine frame 20. The moving unit is supported by the guide rails 20a, 20b, and 20c that are formed integrally with the engine frame 20 and the head unit 300 including the recording head 22 so as to be movable up and down in the directions of arrows C1 and C2. Can be set at various positions as described in (1). Further, an elevating part (not shown) that constitutes a moving means is composed of a head elevating motor or the like, and enables the head unit 300 to elevate. The recovery unit 400 including the capping mechanism 50 is supported by a rail portion (not shown) integrally formed with the engine frame 20 so as to be slidable in the directions of arrows B1 and B2.

  5A to 5E are cross-sectional views taken along the line VV in FIG. 3 when the head unit is located at each position. FIG. 5A shows a reference position of the head unit 300 (hereinafter also referred to as a reference position), and various operations are performed by moving the head unit 300 from the reference position to various positions. Can do. The head unit 300 moves up and down in a direction approaching and separating from the recording medium P in accordance with the rotation direction and amount of rotation of the head lifting motor 118, and each position in the lifting direction is detected by a sensor (not shown). Stop.

  For example, when wiping the ejection port of the head unit 300, the head unit 300 is lowered from the reference position (FIG. 5A) to a wiping position positioned below (FIG. 5B). At the wiping position, the recovery unit 400 is moved with respect to the discharge port forming surface of the recording head 22 of the head unit 300, and the wiper provided in the recovery unit 400 is slidably brought into contact with the discharge port forming surface to perform wiping (cleaning). Thereafter, the wiper is moved together with the recovery unit 400 in the direction of the arrow B1, and is shifted from the position directly below the recording head 22.

  When recording characters and images on the recording medium P, the head unit 300 is lowered to a recording position located below the reference position, and recording is performed on the recording medium P (FIG. 5D). However, before starting the recording, there is a possibility that a problem in the recording quality may occur in the recording head 22 due to the influence of the settled ink or the like, so the operation of stirring the ink in the recording head 22 is performed. At this time, the head unit 300 is raised from the recording position to an inclined position (FIG. 5C) positioned above the reference position. The ink in the recording head 22 can be effectively agitated by the swing generated by moving the head unit 300 from the inclined position to the recording position. After the end of recording, the head unit 300 moves up to the head reference position.

  This movement is not limited to between the recording position and the tilt position, but can be performed between the above-described head reference position, wiping position, and a capping position and tilt position described later. It can also be reciprocated one or more times.

  Furthermore, when performing recovery processing by suction or the like on the recording head 22, the recovery unit 400 is moved in the direction of arrow B2, and the head unit 300 is lowered to a capping position located below the reference position (FIG. 5 (e)). )). At this position, the capping mechanism 50 of the recovery unit 400 capping the recording head 22 of the head unit 300 and performs recovery processing by suction or the like. In order to start image recording after the recovery processing, first, the head unit 300 is raised in the direction of the arrow C1. As a result, the recording head 22 is separated from the capping mechanism 50 and the capping by the capping mechanism 50 is released. The head unit 300 is raised to the wiping position, the wiper provided in the recovery unit 400 is slid, and the ejection port forming surface of the recording head 22 is wiped by the wiper. Thereafter, the head unit 300 is raised to the reference position. After the wiper is moved back to the predetermined position, the recovery unit 400 is moved in the direction of the arrow B1, and the capping mechanism 50 is shifted from the position directly below the recording head 22. Meanwhile, the head unit 300 is lowered in the direction of the arrow C2, and is lowered to a recording position for the recording head 22 to record an image. By ejecting ink from the recording head 22 at this recording position, an image is recorded on the recording medium P that is continuously conveyed in the medium conveying direction A as described above.

  Further, in the present embodiment, the recording head 22 of the head unit 300 is moved between the tilt position and any of the reference position, wiping position, capping position, and recording position, causing the recording head to swing. The ink that has settled in the recording head 22 is stirred.

  FIG. 6 is a perspective view of the head unit including the engine unit as seen from the discharge port side. 7, FIG. 8, and FIG. 9 are a VII arrow view, a VIII arrow view, and an IX arrow view of the head unit of FIG. 6, respectively. A rotation support portion (hereinafter also referred to as a slide bearing) 305 that fits with guide rails 20a, 20b, and 20c for raising and lowering the head unit 300 is attached to the head unit 300.

  As shown in FIG. 10B, the slide bearing 305 has a portion having a shape in which a pair of substantially semicircles having outer peripheral surfaces located on the circumference of the diameter D are opposed to each other. A groove 305a having a width W that fits with the guide rail is formed therebetween. As shown in FIG. 7, two slide bearings 305 for fitting to the guide rail 20 b are attached to the head unit 300, and similarly, one slide bearing 305 is attached to FIG. 9. As shown in FIG. 10E, the slide bearing 305 is formed with a claw 305d, and the claw 305d is elastic with respect to the hole 302b formed at the mounting position of the slide bearing 305 formed in the head unit 300. Can be fixed in place. The slide bearing 305 is attached so as to be rotatable about the center on the diameter D. Further, the slide bearing 305 is formed with a recess 305c and is positioned on the projection 302c of the head unit 300, whereby the rotation range is defined as a predetermined range.

  On the other hand, as shown in FIG. 8, the slide bearing for fitting to the guide rail 20a is different from the other, and a recess 305e having a width wider than the recess 305c of the slide bearing 305 attached in FIGS. 7 and 9 is formed. Yes. When moving to the tilt position, the guide rails 20b and 20c move without rotating the slide bearing 305, but the guide rail 20a rotates and moves the slide bearing 305. As shown in FIG. 11, the guide rail 20 a is positioned by the convex portion 302 b of the head unit 300. In the curved portion 1001a of the guide rail, since there is a gap between the concave portion 305e of the slide bearing 305 and the convex portion 302b of the head unit 300, when the rotation starts, the convex portion 302b also moves in the space of the defined concave portion 305e. The head unit 300 moves to the inclined position. Further, by making the width of the curved portion 1001a of the guide rail 20a narrower than other portions, a gap is formed between the concave portion 305e of the slide bearing 305 and the convex portion 302b of the head unit 300.

  The plurality of ejection ports of the recording head 22 are arranged longer in a direction perpendicular to the conveyance direction of the recording medium than in a direction parallel to the conveyance direction of the recording medium. For this reason, the shape of the liquid chamber of the recording head is correspondingly longer in the direction perpendicular to the conveyance direction of the recording medium than in the direction parallel to the conveyance direction of the recording medium. Therefore, it is desirable to tilt the head in the longitudinal direction when performing agitation to swing the ink settled in the recording head 22 for agitation.

  Further, since the precipitated ink is easier to stir when the amount of ink in the recording head 22 is smaller, it is also effective to swing the recording head 22 in the longitudinal direction after lowering the liquid level of the ink in the recording head 22. Conceivable.

  FIG. 12 is a flowchart illustrating an example of a processing procedure according to the present embodiment. First, in step S1, it is determined whether or not there is a recording instruction. If the determination is affirmative, the process proceeds to step S7 in which the recovery process is performed. The process proceeds to step S3. If a negative determination is made in step S3, the process returns to step S1 and waits for a recording instruction. On the other hand, if an affirmative determination is made, a stirring operation is performed in which the recording head 22 moves from the stop position to the inclined position. Returns to step S1.

  If an instruction to start recording is confirmed in step S1, a recovery process is executed in step S7, and a stirring operation involving raising and lowering and tilting of the recording head 22 is executed in step S9 as described above. In step S11, it is determined whether the up and down movement for stirring is sufficient. If the determination is affirmative, the process proceeds to step S13 for recording on the recording medium P. If the determination is negative, the process returns to the stirring operation in step S9. . The stirring operation in step S9 is effective when a recording start is instructed immediately after the recording apparatus is turned on. Further, it is effective to determine whether or not the stirring operation is sufficient in step S11 because a sufficient stirring operation can be performed according to the power-off time of the recording apparatus.

  In step S15, it is determined whether or not the recording is to be ended. If the determination is affirmative, the recording is ended. After the stirring operation is performed in step S17, the ejection formation surface of the recording head is capped in step S19. That is, the stirring operation is performed in association with the raising / lowering operation for capping. On the other hand, if it is negative determination, it will return to step S13 and will continue recording.

  The timing of the stirring operation can be determined as appropriate, and may not be performed every predetermined time, before the start of the recording operation, and at all timings during the lifting / lowering operation as in the control procedure of FIG. . Implementation / non-execution of the stirring operation can be switched depending on whether or not the recording head is moved to the inclined position.

  As described above, the head unit 300 is reciprocated between the tilt position and any other position by the guide rails 20a, 20b, and 20c provided with the slide bearing 305 and the bending portion 1001a, and the head is swung. Agitate the precipitated ink in the head. Accordingly, it is possible to prevent or suppress the possibility of deterioration in recording quality due to unevenness of liquid viscosity and density due to sedimentation of pigment ink.

(Other)
Note that the present invention is not limited to the above-described embodiments, and appropriate modifications, corrections, substitutions, and the like are possible.

  For example, in the above-described embodiment, the slide bearing that is fitted to the guide rail has a substantially circular planar shape, and the groove is formed. However, the present invention is not limited to the one in which the groove portion is formed, and a pair of guide rollers may be provided and the guide rails may be engaged between the guide rollers. Moreover, although the straight line was illustrated from the curved part to the front-end | tip of a guide rail, you may make it a waveform shape.

  Further, the head holder may be configured to hold the recording head inside in a nested structure, and the recording head may be inclined in the head holder as the head holder moves up and down along the guide rail by the guide rail.

  Furthermore, in the above-described embodiment, the ink jet recording apparatus is exemplified as the liquid discharge recording apparatus. However, the present invention only needs to be able to perform the function of stirring the liquid in the recording head, and can be widely applied as a liquid discharge apparatus that discharges liquid other than ink.

20 Engine frame 20a, 20b, 20c Guide rail 22 Recording head 300 Head unit 305 Slide bearing (bearing)
400 recovery unit 500 pump unit 1001a curved portion P recording medium

Claims (9)

A liquid ejection head having an ejection port for ejecting liquid to the recording medium;
First guiding means for guiding the liquid ejection head in a first direction so as to be separated from and close to the recording medium;
Second guide means for guiding the liquid discharge head in a second direction different from the first direction in accordance with guidance by the first guide means for stirring the liquid in the liquid discharge head;
A liquid ejecting apparatus comprising: The first guide means guides the liquid discharge head to a recovery position for recovering the discharge performance,
The liquid ejecting apparatus according to claim 1, wherein the second guiding unit guides the liquid ejecting head in the second direction at a position farther from the recording medium than the recovery position.   The liquid ejection apparatus according to claim 1, wherein the second direction is a direction inclined with respect to a longitudinal direction of the liquid ejection head. A liquid amount adjusting means capable of adjusting the amount of liquid inside the liquid discharge head;
4. The liquid ejection apparatus according to claim 3, wherein the liquid amount adjusting unit lowers a liquid level of the liquid in the liquid ejection head before guiding the liquid ejection head in the second direction.   The second guiding means moves the liquid ejection head in the second direction based on at least one timing among a predetermined time, before the start of the recording operation, and when moving in the contact / separation direction with respect to the recording medium. 5. The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is guided to the above.   6. The liquid ejection apparatus according to claim 1, wherein the first guide unit includes a guide rail and a slide bearing that is fitted to the guide rail. 7.   The liquid ejection apparatus according to claim 6, wherein the second guide unit is formed as a curved portion of the guide rail.   The liquid ejecting apparatus according to claim 7, wherein a width of the guide rail in the curved portion is narrower than a width other than the curved portion.   A head holder for holding the liquid discharge head in a nested structure; wherein the first guide means guides the head holder, and the second guide means guides the liquid discharge head. The liquid ejection device according to claim 1.

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