JP2020001321A - Liquid ejection device - Google Patents

Abstract

To improve accuracy in adjusting a carriage and a maintenance unit on the basis of the thickness of a recording medium.SOLUTION: A liquid ejection device comprises: liquid ejection heads (recording heads 11a, 11b); a carriage 12 movable in a horizontal direction and a vertical direction, with the liquid ejection heads mounted thereon; a maintenance unit 23 that performs maintenance recovery for the liquid ejection heads and movable in the vertical direction; control means that controls respective movements of the carriage 12 and the maintenance unit 23; and a detector 16 mounted on the carriage 12 and that detects a first distance in a direction perpendicular to the carriage 12 and the recording medium 14 and a second distance in a direction perpendicular to the carriage 12 and the maintenance unit 23. The control means adjusts the height of the carriage 12 by using the first distance detected above the recording medium 14 by the detector 16 and adjusts the height of the maintenance unit 23 by using the second distance detected above the maintenance unit 23 by the detector 16.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an apparatus for discharging a liquid.

In a device that discharges liquid from a large machine such as a flat bed machine, not only the carriage but also the maintenance unit has a lifting function in order to perform image formation more efficiently.
Here, when forming an image on a thick recording medium, the apparatus that discharges the liquid raises the carriage according to the thickness of the recording medium. At this time, it is necessary to raise the maintenance unit as the carriage is raised.
For example, Patent Document 1 discloses a technique in which a distance between a nozzle surface of a carriage and a maintenance unit is measured by a sensor mounted on the carriage, and the carriage is moved up and down based on the measured distance to adjust the distance.
However, Patent Literature 1 does not disclose a technique in which the maintenance unit has a lifting function. Further, when the control unit instructs both the carriage and the maintenance unit to raise the distance (for example, several millimeters) based on the thickness of the recording medium when the carriage and the maintenance unit are moved up and down, a dimensional error or the like may occur. Therefore, there is a problem that the position of the carriage and the position of the maintenance unit do not always match.

  The present invention has been made in view of the above-described problems in the related art. In an apparatus in which a carriage and a maintenance unit eject liquid that can be individually raised and lowered, a carriage and a maintenance unit are provided based on the thickness of a recording medium. The purpose is to improve the accuracy of adjusting.

  In order to solve the above-described problem, a liquid discharging apparatus according to the present invention includes a liquid discharging head that discharges a liquid onto a recording medium, and a liquid discharging head mounted thereon, which can move horizontally and vertically. A carriage, a maintenance unit capable of maintaining and recovering the liquid ejection head, and being movable in the vertical direction, control means for controlling movement of the carriage and the maintenance unit, and a carriage mounted on the carriage, and A first distance that is a distance in the vertical direction with respect to a recording medium, and a detector that detects a second distance that is a distance in the vertical direction between the carriage and the maintenance unit, the control unit includes: The carriage is moved so that the detector is located above the recording medium, and the first distance detected by the detector is calculated. Then, after moving the carriage in the vertical direction, the carriage is moved so that the detector is located above the maintenance unit, and the maintenance is performed using the second distance detected by the detector. The part is moved in the vertical direction.

  ADVANTAGE OF THE INVENTION According to this invention, in the apparatus which discharges the liquid which a carriage and a maintenance part can raise and lower individually, the precision which adjusts a carriage and a maintenance part based on the thickness of a recording medium can be improved.

FIG. 1 is a perspective view illustrating an overall configuration of an inkjet recording apparatus as an example of an apparatus that discharges a liquid according to an embodiment, where (A) is a perspective view as viewed from a front side of the apparatus, and (B) is a perspective view as viewed from a rear side of the apparatus. FIG. FIG. 3 is a schematic diagram illustrating a carriage and a maintenance and recovery mechanism according to one embodiment. FIG. 5 is another schematic diagram illustrating a carriage and a maintenance and recovery mechanism according to one embodiment. It is a block diagram explaining the example of composition of the control means of one embodiment. FIG. 4 is an explanatory diagram schematically showing liquid ejection onto a recording medium. FIG. 4 is another explanatory diagram schematically showing ejection of a liquid to a recording medium. FIG. 4 is a diagram illustrating drive parameters when the control unit of one embodiment drives a maintenance and recovery mechanism. FIG. 2 is a diagram illustrating another configuration example of an image forming apparatus as an example of an apparatus that discharges a liquid according to an embodiment. FIG. 3 is a diagram illustrating a configuration example of a recording head.

  Hereinafter, an embodiment of an apparatus for discharging a liquid according to the present invention will be described with reference to the drawings. The following description and drawings are omitted or simplified as appropriate for clarity of explanation. In the drawings, components having the same configuration or function and corresponding portions are denoted by the same reference numerals, and description thereof will be omitted. It should be noted that the present invention is not limited to the embodiments described below, and can be changed in other embodiments, additions, modifications, deletions, and the like within a range that can be conceived by those skilled in the art. The present invention is also included in the scope of the present invention as long as the functions and effects of the present invention are exhibited.

  FIG. 1 is a perspective view illustrating an overall configuration of an ink jet recording apparatus as an example of an apparatus that discharges a liquid according to an embodiment. FIG. 1A is a perspective view viewed from the front side of the apparatus, and FIG. It is the perspective view seen from.

  The ink jet recording apparatus 10 includes a carriage 12 and a stage 13 on which a recording medium is placed. The carriage 12 is an ink-jet type carriage including a plurality of recording heads (also referred to as “liquid ejection heads”) 11 provided with a plurality of nozzles, and records dots by ejecting liquid from the nozzles of the recording head 11. I do. The nozzle is provided on a surface facing the stage 13. In the present embodiment, the liquid has, for example, ultraviolet curability.

  Further, on the surface of the carriage 12 facing the stage 13, there is provided an irradiating section 33 which is a light source for irradiating ultraviolet rays. The irradiating unit 33 irradiates light having a wavelength that cures the liquid discharged from the nozzle.

  A guide rod 19 is bridged between the left and right side plates 18a and 18b, and the guide rod 19 holds the carriage 12 so as to be movable in the X direction (main scanning direction). The carriage 12, the guide rod 19, and the side plates 18a and 18b are integrally movable along the guide rail 29 provided below the stage 13 in the Y direction (sub-scanning direction). Further, the carriage 12 is held so as to be movable in the Z direction (vertical direction, vertical direction).

  That is, the carriage 12 of the ink jet recording apparatus 10 can scan in the X direction and the Y direction and can move up and down in the vertical direction.

Next, a carriage and a maintenance and recovery mechanism according to an embodiment will be described with reference to FIGS.
The carriage 12 carries the recording heads 11a and 11b (hereinafter, referred to as the "recording head 11" when the two are not distinguished) and the detector 16, and moves in the horizontal direction and also moves in the vertical direction.
The maintenance / recovery mechanism 20 includes wiper portions 21a and 21b (when the two are not distinguished, referred to as "wiper portion 21"), cap portions 22a and 22b (when the two are not distinguished, referred to as "cap portion 22"), a reference surface. 24, and a maintenance and recovery mechanism housing 25 on which these are mounted.
FIG. 2 is a diagram illustrating a state of detecting a vertical distance between the carriage 12 and the recording medium 14, and FIG. 3 is a diagram illustrating a state of detecting a vertical distance between the carriage 12 and the maintenance unit 23. FIG.

The recording head 11 is a liquid ejection head that ejects liquid onto the recording medium 14.
The detector 16 is a sensor that measures the distance to the target, and outputs information on the measured sensor. The detector 16 detects, for example, a first distance that is a vertical distance between the carriage 12 and the recording medium 14 and a second distance that is a vertical distance between the carriage 12 and the maintenance unit 23.

The wiper unit 21 wipes the nozzle surface of the recording head 11.
The cap 22 caps the nozzle surface of the recording head 11.
The maintenance unit 23 performs maintenance and recovery of the recording head 11, and the configuration examples of FIGS. 2 and 3 show an example including the wiper unit 21 and the cap unit 22.
The reference surface 24 is a surface that is used as a reference when the detector 16 detects the vertical distance between the carriage 12 and the maintenance unit 23. The reference surface 24 is a surface having the surface facing the carriage 12 as a reference, and is formed by a surface having the same height as the wiper portion 21 or the cap portion 22. As the reference surface 24, any surface of the wiper portion 21 or the cap portion 22 may be used, and the installation of the reference surface 24 may be omitted.

The liquid ejecting apparatus according to the embodiment adjusts the height (vertical position) of the carriage 12 and the maintenance unit 23 according to the thickness of the recording medium 14 by the following procedure.
(1) First, the detector 16 mounted on the carriage 12 measures the distance (first distance) between the detector 16 and the recording medium 14, and adjusts the carriage height using the measured first distance. I do.
(2) Next, the carriage 12 moves above the maintenance unit 23, and the detector 16 mounted on the carriage 12 measures the distance (second distance) between the carriage 12 and the maintenance unit 23, The maintenance unit 23 is adjusted using the two distances.

The apparatus for ejecting liquid according to one embodiment includes a control unit that controls movement of the carriage 12 and the maintenance unit 23 and the detector 16 to execute the above-described procedure.
FIG. 4 is a block diagram illustrating a configuration example of the control unit 100.
As shown in FIG. 4, the control unit 100 includes a CPU 101, a RAM 102, a ROM 103, an HDD 104, a first control unit 105, a second control unit 106, and an I / O (Input / Output) unit 107. I have.

  For example, when part or all of the program is implemented by a program, the control unit 100 reads the program stored in a storage medium (such as the ROM 103 or the HDD 104) into the RAM 102 and causes the CPU 101 to execute a group of instructions of the program. The control means may be partially or entirely constituted by hardware. For example, as in an embedded system, it may be realized by a combination of hardware and software, or may be configured by any of hardware, firmware, and software, or a combination of two or more of these.

  The CPU (Central Processing Unit) 101 is a control mechanism that controls the overall operation of the control unit 100. The CPU 101 controls the entire operation of the control unit 100 by reading and executing a control program or the like stored in a ROM (Read Only Memory) 103.

  A RAM (Random Access Memory) 102 is a storage medium used as a work area when a control program executed by the CPU 101 is executed. The RAM 102 temporarily stores, for example, image data and the like.

  The ROM 103 and the HDD (Hard Disk Drive) 104 are storage media for storing programs executed by the CPU 301 and the like. The ROM 103 stores, for example, the control program, a threshold used in the present embodiment, and other fixed data.

The first control unit 105 controls the first driving unit 15. The first drive unit 15 is a drive mechanism that moves the carriage in the horizontal direction and the vertical direction, and uses, for example, a motor.
The second control unit 106 controls the second driving unit 26. The second drive unit 26 is a drive mechanism that moves the maintenance and recovery mechanism 20 including the maintenance unit in the vertical direction, and uses, for example, a motor. The second drive unit 26 has a drive mechanism different from that of the first drive unit 15.
The I / O unit 107 receives the sensor information measured by the detector 16.

The control unit 100 executes, for example, the following processing.
The first control unit 105 causes the first drive unit 15 to move the carriage 12 so that the detector 16 is located above the recording medium 14, and causes the detector 16 to detect the first distance. The detector 16 measures a vertical length from the detector 16 to the surface of the recording medium 14 as a first distance. The first control unit 105 acquires the first distance detected by the detector 16 via the I / O unit 107, and uses the first distance to determine the distance between the detector 16 and the recording medium 14 in the vertical direction. The carriage 12 is moved up and down in the vertical direction by the first drive unit 15 so as to have one desired value.

  Thereafter, the first control unit 105 causes the first drive unit 15 to move the carriage 12 above the reference surface 24 as a height detection surface provided in the maintenance / recovery mechanism 20, and the detector 16 detects the second distance. Let it. The detector 16 measures a vertical length from the carriage 12 to the surface of the reference surface 24 as a second distance. The second control unit 106 acquires the second distance detected by the detector 16 via the I / O unit 107, and uses the second distance to determine the vertical distance between the detector 16 and the maintenance unit 23 as the second distance. The maintenance / recovery mechanism 20 in which the maintenance unit 23 is disposed in the second drive unit 26 is vertically moved so as to have the two desired values.

  Here, the first desired value and the second desired value are preset numerical values, and are stored in a storage area (for example, the ROM 103) to which the control unit 100 can refer. The first desired value is a desired value of a vertical distance between the carriage 12 and the recording medium 14 (the surface of the recording medium 14 facing the carriage 12). The second desired value is a desired value of the vertical distance between the carriage 12 and the reference surface 24 of the maintenance / recovery mechanism.

  The configuration and form of the control unit 100 are not particularly limited. For example, an encoder sensor and an encoder slit can be mounted so that the positions of the wiper unit 21 and the carriage 12 can be read. Further, the liquid ejecting apparatus may include an operation / display unit for receiving and displaying information necessary for the liquid ejection apparatus, and may input and output information to and from the outside via an I / O unit.

  In the present application, the “device that discharges liquid” is a device that includes a liquid discharge head and drives the liquid discharge head to discharge liquid. The “device that discharges liquid” may include means for feeding, transporting, and discharging paper to which liquid can be attached, as well as a pre-processing device and a post-processing device. The device that discharges a liquid includes not only a device that can discharge a liquid to an object to which the liquid can be attached, but also a device that discharges the liquid into the air or into the liquid.

As the “device for discharging liquid”, for example, there is an image forming device (inkjet recording device) that is a device for discharging ink to form an image on a recording medium (paper).
Further, the “device for discharging liquid” is not limited to a device in which a significant image such as a character or a graphic is visualized by the discharged liquid.

  The above-mentioned "thing to which a liquid can be attached" means a thing to which a liquid can be attached at least temporarily, such as a thing which adheres and adheres, a thing which adheres and penetrates, and the like. Examples of "things to which a liquid can be attached" include recording media such as paper, recording paper, recording paper, film, cloth, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), and organ models. And an inspection cell. As long as there is no particular limitation, anything to which the liquid adheres may be used. Examples of the material to which "the liquid can be attached" include materials to which the liquid can be attached even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

  The “liquid” is not particularly limited as long as it has a viscosity and a surface tension that can be ejected from the head. The liquid has a viscosity of 30 mPa · s or less at normal temperature and normal pressure, or by heating and cooling. Is preferred. Examples of the “liquid” include solvents such as water and organic solvents, coloring agents such as dyes and pigments, functionalizing materials such as polymerizable compounds, resins, and surfactants, and biological materials such as DNA, amino acids, proteins, and calcium. Solutions, suspensions, emulsions, and the like, including compatible materials, edible materials such as natural pigments, and the like are included. These can be used, for example, for ink jet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements, liquids for forming resist patterns for electronic circuits, and three-dimensional modeling material liquids.

  The liquid discharged in the liquid discharging apparatus of the present embodiment has stimulus-curing properties. The stimulus is, for example, light (ultraviolet light, infrared light, etc.), heat, electricity, or the like. For example, a liquid that is cured by light is used, and specifically, a photo-curable ink that is cured by light irradiation is used. An example of a unit for curing the liquid with light is a UV light source (the irradiation unit 33 shown in FIG. 1).

  The “device that discharges liquid” includes a device in which a liquid discharge head and a device to which liquid can be attached relatively move, but is not limited thereto. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

  Other examples of the “liquid discharging device” include a processing liquid coating device that discharges a processing liquid onto a paper in order to apply the processing liquid to the surface of the paper for the purpose of modifying the surface of the paper, and a raw material. There is an injection granulating apparatus for granulating fine particles of a raw material by spraying a composition liquid in which a solution is dispersed through a nozzle.

  The “liquid ejection head” is a single functional component that ejects and ejects a liquid from a nozzle. Further, the "liquid ejection head" is not limited to the pressure generating means to be used. As an energy generating source for discharging a liquid, for example, a piezoelectric actuator (laminated piezoelectric element and thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heating resistor, an electrostatic actuator including a diaphragm and a counter electrode, and the like Are used.

  Further, image forming, recording, printing, printing, printing, modeling, and the like in the terms of the present application are all synonyms.

  Hereinafter, an ink jet recording apparatus that ejects a photo-curable ink will be described as an example of an apparatus that ejects a liquid according to an embodiment. Here, it will be described that the height adjustment of the carriage 12 and the maintenance / recovery mechanism 20 by the control unit 100 is necessary.

  A recording technique in an ink jet recording apparatus is characterized in that an image can be recorded without contacting a recording medium. Non-contact printing enables image recording not only on smooth media such as paper and film, but also on media with uneven surfaces or thick media. Has been introduced.

The technology that enables non-contact printing is a technique in which ink droplets are ejected from a liquid ejection head (recording head). The principle of ejection is to press an ink chamber in the recording head with electric or thermal energy to cause an arbitrary ink droplet to fly from a micro-scale nozzle opening. Since the above-described members eject ink droplets in a related manner, a target image cannot be obtained if any of the members has a problem. Further, even if the ink droplets are ejected, a target image cannot be obtained unless the ink droplets land on the recording medium accurately.
Regarding the impact of ink droplets on the recording medium, a particularly important factor is the distance (gap) between the recording head (liquid ejection head) and the recording medium. Countermeasures against the problem that the gap is disturbed to cause a problem in the recorded image will be described with reference to FIGS.

FIGS. 5 and 6 are schematic diagrams illustrating liquid ejection to a recording medium.
FIG. 5 is a side view of a device that discharges a liquid. A recording medium 14 is placed on a stage 13, and an ink droplet 41 is discharged from the recording head 11 onto the recording medium 14 in a direction indicated by an arrow 41 a. FIG.
It is preferable that the gap from the recording head 11 to the recording medium 14 is always constant. Since the optimal value of the gap from the recording head 11 to the recording medium 14 is determined by the applied ink and the characteristic value of the recording head 11, it is difficult for a user to change the optimal gap according to the apparatus.

Since the gap from the recording head 11 to the recording medium 14 changes depending on the thickness t of the recording medium 14, it is preferable to provide a system in which the carriage 12 moves up and down according to the thickness t.
For example, the height of the carriage 12 when printing the recording medium 14 having a thickness t1 of 1 mm shown in FIG. At this time, when printing on a recording medium 14 having a thickness t2 of, for example, 30 mm shown in FIG. 5B, the height of the carriage 12 is raised by 29 mm as compared with FIG. 5A (moved in the direction of arrow D2). By doing so, the gap can be kept constant and an image of the same quality can be obtained.

  In order to keep the gap constant in this manner, a detection unit (for example, the detector 16 in FIGS. 2 and 3) for detecting the thickness of the recording medium 14 onto which the liquid is ejected is provided, and according to the detection result of the detection unit. It is preferable that the lifting distance of the carriage 12 is adjusted. FIG. 6 shows an example in which the detecting means is provided.

FIG. 6 is a side view of an apparatus for ejecting a liquid, similarly to FIG. 5, in which a recording medium 14 is mounted on a stage 13 and ink droplets 41 are ejected from the recording head 11 onto the recording medium 14. It is a state schematically shown.
FIG. 6A is an example in which the carriage 12 is located at a position that is excessively high with respect to the thickness t1 (for example, 1 mm) of the recording medium 14. When the ink droplet 41 is ejected from the nozzle of the recording head 11 in the direction shown by the arrow 41a without adjusting the gap, the ink droplet 41 becomes an ink mist 42 in the air before landing on the recording medium 14, and is used for image formation. It does not matter.
The ink droplet 41 that has become an ink mist 42 in the air adheres to an unspecified portion in the apparatus, and is cured and fixed by irradiation light. If it adheres to the recording medium 14, the quality of the image is reduced, and if it adheres to a member of the apparatus, it may cause a failure.

On the other hand, FIG. 6B shows that the carriage 12 is lowered in the direction indicated by D2 in accordance with the detection result (for example, the above-described first distance) of the detection means 17 for detecting the thickness t1 of the recording medium 14 to reduce the gap. The state after the adjustment is shown.
In the example of FIG. 6B, an image of a desired quality can be formed by adjusting the position of the carriage so as to obtain an optimum gap.

  As the detection means 17, for example, a device that irradiates a laser beam and calculates a distance based on reflected light reflected from an object can be used. In the present embodiment, the detection unit 17 using the laser reflected light is mounted, but the detection unit 17 is not particularly limited as long as the detection unit 17 can detect the thickness of the recording medium 14. A detection device may be provided that measures the thickness of the recording medium 14 by a physical return amount.

  In the liquid ejecting apparatus according to one embodiment, it is preferable that the maintenance and recovery mechanism 20 be moved up and down by the same distance as the carriage 12 is moved up and down. This is because even if the carriage 12 is moved up and down according to the thickness of the recording medium 14 and a clear image can be formed, the nozzle surface cannot be wiped unless the maintenance and recovery mechanism 20 is at the same height. If the height of the maintenance / recovery mechanism 20 does not fluctuate, the carriage 12 needs to return to the initial position every time an image is recorded, resulting in increased waste of operation.

  In one embodiment, as described with reference to FIG. 3, also when adjusting the position of the maintenance / recovery mechanism 20, the detection result (second distance) of the detector 16 is used to adjust the position of the maintenance / recovery mechanism 20. Adjust the position. This makes it possible to adjust the maintenance and recovery mechanism 20 to an appropriate position according to the thickness of the recording medium 14.

  Further, as described below, the control unit 100 obtains an approximate expression of the height of the maintenance / recovery mechanism 20 corresponding to the thicknesses of the plurality of different recording media 14 and adjusts the height of the maintenance / recovery mechanism 20. It is also possible to take a method of calculating the drive parameters used for the above. This will be described with reference to FIGS.

  In the apparatus for ejecting liquid described with reference to FIGS. 2 and 3 described above, for example, in order to perform recording on a recording medium 14 having a large thickness, a detector 16 provided on a carriage 12 supporting a recording head 11 is used. It has a carriage 12 that can move up and down by detecting the thickness of the recording medium 14. The apparatus that discharges the liquid detects the height of the maintenance / recovery mechanism 20 with respect to the height of the recording medium 14 having a plurality of different thicknesses, and calculates the approximate expression of the detected height of the maintenance / recovery mechanism 20 with respect to the thickness of the recording medium 14. , The drive parameters at the time of raising and lowering the maintenance and recovery mechanism 20 can be corrected. As a device for discharging such a liquid, for example, there is a flat bed type image forming device using an ink jet system.

In the maintenance / recovery mechanism 20, the reference height (height of the reference surface 24) and the height at the time of ascending and descending by motor driving (an example of the driving mechanism of the second driving unit 26) are the same depending on the tolerance and precision of the parts. The driving amount also varies in height.
For this reason, when maintenance is performed by the maintenance unit 23 of the maintenance and recovery mechanism 20 in a state where the recording medium 14 having a large thickness is installed, the actual elevation amount varies with respect to the drive parameters at the time of elevation, which hinders the maintenance operation. May come out.

  In one embodiment, the control unit 100 uses the detector 16 provided on the carriage 12 on which the recording head 11 is stretched to determine the reference of the maintenance / recovery mechanism 20 when printing on the recording medium 14 having a plurality of thicknesses. From the height of the surface 24, an approximate expression based on the detection height of the maintenance / recovery mechanism with respect to the thickness of the recording medium 14 is obtained. By correcting the drive parameters of the maintenance / recovery mechanism 20 when the maintenance / recovery mechanism 20 moves up and down based on the approximate expression, the elevation amount of the maintenance / recovery mechanism 20 can be optimized for each unit of the maintenance / recovery mechanism.

For example, the control unit 100 detects a plurality of combinations of the first distance and the second distance with respect to a plurality of recording media having different thicknesses, and calculates an approximate expression of a second distance corresponding to the plurality of recording media having different thicknesses. Alternatively, an approximate expression of the second distance corresponding to the first distance is obtained, and the driving parameter when the maintenance unit 23 moves in the vertical direction is corrected. The drive parameter is, for example, a parameter instructed from the second control unit 106 to the second drive unit 26.
Thereby, an approximate expression of the detected height of the maintenance / recovery mechanism 20 with respect to the thickness of the recording medium 14 is obtained, and the drive parameter at the time of elevation of the maintenance / recovery mechanism 20 is corrected. Can be optimized.

  FIG. 7 is a diagram illustrating drive parameters when the control unit of one embodiment drives the maintenance and recovery mechanism. The thickness of the recording medium 14 and the height of the maintenance / recovery mechanism 20 are associated with each other based on the unit design value of the maintenance / recovery mechanism 20. FIG. 7 shows a unit design value of the maintenance / recovery mechanism 20 and an approximate expression of the two units A and B.

More specifically, the control unit 100 obtains an approximate expression using the design values of the units of the maintenance and recovery mechanism 20 according to the following procedure.
(A) The recording medium 14 or the measurement member is detected by a pressure-sensitive detection mechanism (for example, a detector 16) provided in the carriage 12, and the height of the carriage 12 is stored. The measurement member is, for example, a member serving as a reference for detecting the height of the carriage 12.
(B) With respect to the height of the carriage 12 detected in (a), the maintenance / recovery mechanism 20 is raised until the detector 16 of the carriage 12 detects the height.
(C) When the detector 16 of the carriage 12 detects the maintenance / recovery mechanism 20, the height of the maintenance / recovery mechanism 20 from the reference surface 24 is obtained based on the height value of the carriage 12 recorded in (a). To remember.
(D) The procedure of (a) to (c) is detected by two or more types of recording media 14 or measurement members having different thicknesses, and an approximate expression is derived from the values of two or more points. Applies to lifting parameters.
According to the above-described procedure, the maintenance / recovery mechanism 20 can be accurately moved up and down according to the height of the carriage 12.

In addition, it is preferable that the control unit 100 re-detects the height of the reference plane 24 by the detector 16 after the unit replacement of the maintenance / recovery mechanism 20 including the maintenance unit, and obtains the above-described approximate expression.
The height of the reference surface 24 of the maintenance / recovery mechanism 20 and the height when the motor is driven up and down vary depending on the tolerance and accuracy of parts even with the same motor drive amount.
Therefore, after replacing the unit of the maintenance / recovery mechanism 20, the control means re-detects the height of the reference plane 24 by the detector 16 to obtain an approximate expression of the detected height of the maintenance / recovery mechanism 20, and The drive parameters at the time of lifting / lowering of 20 are corrected again. This makes it possible to optimize the amount of elevation of the maintenance / recovery mechanism 20 after replacement with a unit having a different characteristic.

Next, details of a recording head and supply of ink of the image forming apparatus according to the embodiment will be described.
FIG. 8 is a diagram illustrating another configuration example of the image forming apparatus according to the embodiment. FIG. 9 is a diagram illustrating a configuration example of a recording head.
The image forming apparatus 10A includes a carriage 92 that reciprocates (bidirectional scanning) in a forward direction D21 and a backward direction D22, and a transport stage 93 that transports a recording medium 94. The carriage 92 is provided with recording heads 50k, 50c, 50m, and 50y each having a plurality of ejection heads for ejecting ink droplets (hereinafter, referred to as a “recording head 50” when a color is not distinguished). To form an image by scanning in an orthogonal direction.

  Further, a main tank loading unit 60 for loading ink used for recording is provided at one end of the front surface of the main body of the image forming apparatus 10A. The main tank loading unit 60 can be replaced at any time with a plurality of recording liquids (inks) of different colors, such as black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. Main tanks 61k, 61c, 61m, and 61y, which are main tanks of the recording liquid (hereinafter, referred to as “main tank 61” when colors are not distinguished) can be loaded.

The carriage 92 is slidably held in the main scanning direction, and reciprocates and scans in a direction indicated by reference numerals D21 and D22 (carriage main scanning direction) by a main scanning motor (not shown).
The carriage 92 includes, as described above, the recording heads 50k, 50c including four droplet discharge heads for discharging ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk), respectively. A plurality of ink ejection openings 50m and 50y are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

As an ink jet head constituting the recording head 50 shown in FIG. 9, a piezoelectric actuator such as a piezoelectric element, a thermal actuator utilizing an electrothermal conversion element such as a heating resistor and utilizing a phase change due to film boiling of a liquid, and a thermal actuator utilizing a temperature change A device including a shape memory alloy actuator using a metal phase change, an electrostatic actuator using an electrostatic force, or the like as a pressure generating unit that generates a pressure for discharging a droplet can be used.
The recording head 50 has a driver IC mounted thereon and is connected to control means (not shown, for example, the control means 100 in FIG. 4) via a harness (flexible print cable).

  The recording head 50 includes two ink ports 52a and 52b provided on both sides of the frame portion 51 and a common liquid chamber 53 communicating with the ink ports 52a and 52b. An actuator 54 is provided as a means, and the recording liquid (ink) in the individual liquid chamber 55 is generated by generating a pressure with respect to the individual liquid chamber 55 (reference numerals 55a, 55b, 55c,...) In the individual liquid chamber 55. The ink is discharged from the nozzles 56 (reference numerals 56a, 56b, 56c,... In FIG. 9).

The carriage 92 is provided with sub-tanks 71 k, 71 c, 71 m, and 71 y for each color for supplying ink of each color to the recording head 50 (hereinafter, referred to as “sub-tank 71” when colors are not distinguished).
As described above, the sub-tank 71 of each color is attached to the main tank loading section 60 via the ink supply tubes 72k, 72c, 72m, and 72y of each color (hereinafter, referred to as “ink supply tube 72” when no distinction is made between colors). The ink of each color is replenished and supplied from the main tank 61 of each color.

Air pump units 73k, 73c, 73m, and 73y are provided on the upper part of the sub-tank 71 as negative pressure forming means for maintaining the pressure inside the sub-tank at a negative pressure to secure discharge stability. 73 ").
The main tank loading section 60 is provided with supply pump units 62k, 62c, 62m, and 62y for supplying ink in the main tank 61 (hereinafter referred to as "supply pump 62" when colors are not distinguished).

In a non-printing area on one side of the carriage 92 in the scanning direction, a maintenance and recovery mechanism 80 for maintaining and recovering the stable ejection state of the recording head 50 is arranged.
The maintenance and recovery mechanism 80 includes cap members (hereinafter, referred to as “caps”) 81a, 81b, 81c, and 81d (hereinafter, referred to as “caps 81” when no distinction is made) for capping each nozzle surface of the recording head 50. ing.

With the cap 81 capped on the recording head 50, the pump is driven to generate a negative pressure inside the cap 81, and ink is sucked from the nozzles 56 of the recording head 50, thereby changing the ejection state of the recording head 50. A suction pump 82 for recovery is provided.
In the example of the configuration of the image forming apparatus 10A in FIG. 8, the suction pump 82 uses one pump to sequentially suction the four recording heads 50. Therefore, only the cap 81k can be sucked, and the cap 81c, 81m and 81y function as protective caps for preventing drying of the nozzles 56 of the recording head 50 and attachment of foreign matter during non-printing, but may have a configuration in which suction pumps are provided by the number of recording heads of each color.
Then, the ink discharged from the cap 81 generated by the maintenance and recovery operation by the maintenance and recovery mechanism 80 is discharged and stored in a waste liquid tank 83 which is a waste liquid storage unit.

  As described above, according to the preferred embodiment of the present invention, the height of the carriage and the height of the maintenance unit are measured by the same detector, and the carriage and the maintenance unit are measured based on the values actually measured. Can be raised and lowered.

Reference Signs List 10 inkjet recording devices 11, 11a, 11b, 50k, 50c, 50m, 50y Recording head 12, 92 Carriage 13, 93 Stage 14, 94 Recording medium 15 First driving unit 16 Detector 17 Detecting means 20, 80 Maintenance / recovery mechanism 21 , 21a, 21b Wiper part 22, 22a, 22b, 81a, 81b, 81c, 81d Cap part 24 Reference surface 25 Maintenance / recovery mechanism housing 26 Second driving part 100 Control means 105 First control part 106 Second control part

JP 2010-000439 A

Claims (5)

A liquid ejection head that ejects liquid onto a recording medium,
A carriage mounted with the liquid ejection head and movable in the horizontal direction and movable in the vertical direction;
Performing a maintenance and recovery of the liquid ejection head, the maintenance unit movable in the vertical direction,
Control means for controlling the movement of the carriage and the maintenance unit;
A detector mounted on the carriage and detecting a first distance that is a distance in the vertical direction between the carriage and the recording medium, and a second distance that is a distance in the vertical direction between the carriage and the maintenance unit. And
The control means moves the carriage so that the detector is located above the recording medium, and uses the first distance detected by the detector to move the carriage in the vertical direction. Moving the carriage so that the detector is positioned above the maintenance unit, and moving the maintenance unit in the vertical direction using the second distance detected by the detector. A device that discharges liquid.   The control unit moves the carriage in the vertical direction so that a distance in the vertical direction between the carriage and the recording medium is a first desired value, and moves the carriage and the maintenance unit in the vertical direction. The liquid ejecting apparatus according to claim 1, wherein the maintenance unit is moved in the vertical direction such that the distance becomes a second desired value.   The control unit controls a first drive unit that moves the carriage using the first distance, and controls a second drive unit different from the first drive unit using the second distance. 3. The apparatus according to claim 1, wherein the maintenance unit is moved.   The control unit detects a plurality of combinations of the first distance and the second distance with respect to a plurality of recording media having different thicknesses, obtains an approximate expression of the second distance with respect to the first distance, and The apparatus according to any one of claims 1 to 3, wherein a driving parameter at the time of moving the unit in the vertical direction is corrected.   5. The apparatus according to claim 4, wherein the control unit calculates the approximate expression when the maintenance unit is attached or replaced. 6.