JP5861380B2 - Liquid ejector - Google Patents

Description

  The present invention relates to a liquid ejecting apparatus.

  As a liquid ejecting apparatus, an ink jet printer (liquid ejecting apparatus) that ejects ink (liquid) onto a recording medium from a nozzle (ejection port) of a recording head (ejection head) is known. In a printer, for example, ink jetting speed or jetting amount may decrease due to increase in ink viscosity, resulting in jetting failure. Therefore, in order to maintain the ink ejection characteristics, a print head cleaning process has been conventionally performed.

  Patent Document 1 below discloses a technique for performing a wiping operation as a cleaning process for forcibly discharging ink from a nozzle by a suction operation and then wiping the ink attached to the nozzle formation surface (ejection surface) by a wiping member. ing. Such a wiping member is formed so that the surface is liquid repellent to prevent ink from adhering to the surface.

JP 2010-052381 A

  However, when a wiping operation is performed using a wiping member having a liquid-repellent surface, it is possible to prevent ink from adhering to the wiping member after the wiping operation, but ink remains on the nozzle forming surface during wiping. May end up.

  In view of the circumstances as described above, it is an object of the present invention to provide a liquid ejecting apparatus that can prevent liquid from remaining on the ejection surface and can prevent ink from adhering to the surface of the wiping member. To do.

The liquid ejecting apparatus according to the present invention includes a liquid ejecting head having an ejecting surface for ejecting liquid, an insulating layer formed on the surface, a wiping unit for wiping the ejecting surface, and a first member provided inside the wiping unit. The surface of the wiping unit is made lyophilic with respect to the liquid by applying a voltage between one electrode, a second electrode provided on the ejection surface, and the first electrode and the second electrode. A control unit that releases the voltage between the first electrode and the second electrode to make the surface of the wiping unit liquid repellent with respect to the liquid, and the liquid jet head includes the jet head A plurality of nozzles arranged on the surface in the first direction, the plurality of nozzle rows being provided in a second direction intersecting the first direction, Wipe the jetting surface in two directions, The control unit applies a voltage between the first electrode and the second electrode when passing through the nozzle row, and moves between the first electrode and the second electrode when moving between the nozzle rows. cancel the application of the voltage between the second electrode.

  According to the present invention, by adjusting the potential of the first electrode provided inside the wiping portion having the insulating layer formed on the surface, the affinity for the liquid charged with the positive or negative charge on the surface of the wiping portion is achieved. Since the property can be adjusted, the surface of the wiping unit can be made lyophilic when the ejection surface is wiped using the wiping unit. Thereby, it is possible to prevent the liquid from remaining on the ejection surface.

  In the liquid ejecting apparatus, it is preferable that the wiping portion is formed so that a surface thereof is liquid repellent with respect to the liquid.

  According to the present invention, since the surface of the wiping part is formed so as to be liquid repellent with respect to the liquid, the surface of the wiping part is made liquid repellent by bringing the potential of the first electrode close to 0 after the wiping operation. It is possible to prevent the liquid from adhering to the wiping portion.

  In the liquid ejecting apparatus, the control unit includes a second electrode on the ejection surface, and applies a voltage between the first electrode and the second electrode so that the surface of the wiping unit is disposed on the liquid. It is preferable to make the surface of the wiping part liquid repellent with respect to the liquid by releasing the voltage between the first electrode and the second electrode.

  According to the present invention, the control unit has a second electrode on the ejection surface, and the surface of the wiping unit is made lyophilic with respect to the liquid by applying a voltage between the first electrode and the second electrode. Since the surface of the wiping part is made liquid repellent with respect to the liquid by releasing the voltage between the first electrode and the second electrode, the voltage is applied between the first electrode and the second electrode. By adjusting the voltage, the degree of liquid repellency or lyophilicity of the surface of the wiping portion can be adjusted.

  In the liquid ejecting apparatus, the control unit applies a voltage between the first electrode and the second electrode during a period in which the wiping unit wipes the ejection surface, and the wiping unit It is preferable to release the voltage applied between the first electrode and the second electrode when separated from the ejection surface.

  According to the present invention, a voltage is applied between the first electrode and the second electrode during a period in which the wiping unit wipes the ejection surface, and the first electrode and the second electrode are removed when the wiping unit moves away from the ejection surface. Since the voltage applied between the electrodes is released, the period during which the voltage is applied only needs to be the period during which the wiping unit wipes the ejection surface, and power consumption due to the voltage application can be suppressed.

  In the liquid ejecting apparatus, the liquid ejecting head includes a plurality of nozzles provided on the ejecting surface and arranged in a first direction, and the plurality of nozzle rows intersects the first direction. The wiping unit wipes the ejection surface in the second direction, and the control unit passes through the nozzle rows when the first electrode and the second electrode are provided. Preferably, a voltage is applied between the first electrode and the second electrode when moving between the nozzle rows.

  According to the present invention, since the surface of the wiping unit becomes liquid-repellent while the wiping unit moves between the nozzle rows, after wiping one nozzle row, before wiping the next nozzle row, The liquid adhering to the wiping part can be removed. Thereby, it is possible to prevent liquids from being mixed in different nozzle arrays.

1 is a diagram illustrating a configuration of a printer according to an embodiment. The figure which shows the structure of a head and a wiping mechanism. FIG. 2 is a block diagram illustrating an electrical configuration of the printer. The figure which shows the structure of an ink supply system. The figure which shows the mode of the wiping operation | movement of a printer. The figure which shows the mode of the wiping operation | movement of a printer. The figure which shows the mode of the wiping operation | movement of a printer. The figure which shows the mode of the wiping operation | movement of a printer. FIG. 6 is a diagram illustrating another configuration of a printer. The figure which shows the mode of the wiping operation | movement of a printer.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing, each member has a different scale so that each member has a size that can be recognized on the drawing.

  FIG. 1 is a diagram illustrating a schematic configuration of an embodiment of a liquid ejecting apparatus according to the invention. In FIG. 1, reference numeral 100 denotes an ink jet printer as a liquid ejecting apparatus. The printer 100 is a device that performs a printing process while conveying a sheet-like medium M such as paper or a plastic sheet. The printer 100 includes a housing 101, an ink jet mechanism 102 that ejects ink onto the medium M, an ink supply mechanism 103 that supplies ink to the ink jet mechanism 102, a transport mechanism 104 that transports the medium M, and an ink jet mechanism 102. A maintenance mechanism 105 that performs maintenance operations and a control device (control unit) 106 that controls these mechanisms are provided.

  Hereinafter, the XYZ rectangular coordinate system is set, and the positional relationship of each component will be described with reference to the XYZ rectangular coordinate system as appropriate. In this embodiment, the liquid ejection direction is the Z direction, the head moving direction is the Y direction, and the direction orthogonal to the Z direction and the Y direction is the X direction.

  The casing 101 is formed so that the Y direction is the longitudinal direction. The casing 101 is provided with each part of the ink jet mechanism 102, the ink supply mechanism 103, the transport mechanism 104, the maintenance mechanism 105, and the control device 106. The casing 101 is provided with a platen 13. The platen 13 is a support member that supports the medium M, and is disposed at the center in the X direction in the housing 101. The platen 13 has a flat surface (not shown) oriented in the + Z direction, and this flat surface is used as a support surface that supports the medium M.

  The transport mechanism 104 includes a transport roller, a motor that drives the transport roller, and the like. The transport mechanism 104 transports the medium M from the −X side of the housing 101 into the housing 101 and discharges the medium M from the + X side of the housing 101 to the outside of the housing 101. Further, the transport mechanism 104 transports the medium M so that the medium M passes over the platen 13 inside the housing 101. Further, the transport mechanism 104 is controlled by a control device 106 such as transport timing and transport amount.

  The ink jet mechanism 102 includes a head (jet head) 110 that ejects ink (liquid), and a head moving mechanism 107 that holds and moves the head 110. The head 110 ejects ink toward the medium M sent onto the platen 13. In this embodiment, the ink ejected from the head 110 is conductive and aqueous containing an electrolyte. The head 110 has an ejection surface (nozzle formation surface) 110a that ejects ink. The ejection surface 110 a is oriented in the −Z direction and is disposed so as to face the flat surface of the platen 13.

  The head moving mechanism 107 has a carriage 4, and the head 110 is fixed to the carriage 4. The carriage 4 is in contact with a guide shaft 8 that extends in the longitudinal direction (Y direction) of the housing 101. The head 110 and the carriage 4 are arranged above the platen 13 (+ Z direction).

  In addition to the carriage 4, the head moving mechanism 107 includes a pulse motor 9, a driving pulley 10 that is rotationally driven by the pulse motor 9, and the driving pulley 10 that is provided on the opposite side in the width direction of the housing 101. A pulley 11, and a timing belt 12 that is stretched between the drive pulley 10 and the idle pulley 11 and connected to the carriage 4 are provided. The carriage 4 is connected to a timing belt 12 and is provided so as to be movable in the Y direction as the timing belt 12 rotates. When moving in the Y direction, the carriage 4 is guided by a guide shaft 8.

  The ink supply mechanism 103 is for supplying ink to the head 110. A plurality of ink cartridges 6 are accommodated in the ink supply mechanism 103. The printer 100 according to this embodiment has a configuration (off-carriage type) in which the ink cartridge 6 is accommodated at a position different from the head 110. The ink supply mechanism 103 has a supply tube TB that connects the head 110 and the ink cartridge 6. The ink supply mechanism 103 has a pump mechanism (not shown) that supplies the ink stored in the ink cartridge 6 to the head 110 via the supply tube TB.

  The maintenance mechanism 105 is disposed at the home position of the head 110. This home position is set in an area outside the area where printing is performed on the medium M. In the present embodiment, the home position is set on the Y side of the platen 13. The home position is a place where the head 110 waits when the printer 100 is turned off, when recording is not performed for a long time, or when maintenance work is performed.

  The maintenance mechanism 105 includes a wiping mechanism 111 that wipes the ejection surface 110a of the head 110, a capping mechanism 112 that covers the ejection surface 110a, and a flushing mechanism 115 that performs a flushing process for discharging ink from the nozzles Nz of the head 110. ,have.

  The wiping mechanism 111 includes a wiping member 150 (see FIG. 2) and a support base 151 that can face the ejection surface 110a of the head 110. The wiping mechanism 111 removes ink remaining on the ejection surface 110a and foreign matter adhering to the ejection surface 110a by wiping the ejection surface 110a with the wiping member 150.

A suction mechanism 113 such as a suction pump is connected to the capping mechanism 112. The suction mechanism 113 allows the capping mechanism 112 to suck the space on the ejection surface 110a while covering the ejection surface 110a of the head 110. When suction is performed in this way, ink in the head 110 is sucked through the nozzle Nz. At that time, the ink may splash and adhere to the ejection surface 110a. Therefore, after such a suction operation, the wiping mechanism 111 wipes the ejection surface 110a.
The waste ink discharged from the head 110 to the maintenance mechanism 105 side is collected by, for example, a waste liquid collection mechanism (not shown).

  The flushing mechanism 115 includes a flushing box (not shown), for example, and forcibly discharges ink from each nozzle Nz of the head 110 into the flushing box, thereby clogging due to thickening of the ink. It is intended to be solved or prevented beforehand.

  Further, the printer 100 according to the present embodiment has a supply system (not shown) that supplies ink to the head 110 side via the supply tube TB by pressurizing the ink pack provided in the ink cartridge 6. Yes. The supply system includes an expansion / contraction member that can pressurize the ink pack by expansion and contraction, a pump, and a transport tube that conveys air sent from the pump to the expansion / contraction member. The pump is electrically connected to the control device 106, and its driving is controlled by the control device 106.

FIG. 2 is a diagram illustrating a cross-sectional configuration of the wiping mechanism 111. FIG. 2 shows a state where the head 110 is disposed at the home position.
As shown in FIG. 2, the wiping member 150 is provided with an insulating layer 50 on the surface. A first electrode 51 is provided inside the wiping member 150.

  The insulating layer 50 is electrically insulative and has liquid repellency with respect to conductive ink when no voltage is applied. Therefore, the insulating layer 50 has low ink wettability and a large ink contact angle when no voltage is applied. As such an insulating layer 50, for example, a fluororesin film such as Teflon (registered trademark), a parylene film formed by a chemical vapor deposition method, or the like is used. The thickness of the insulating layer 50 is set such that the phenomenon described later is sufficiently caused by the first electrode 51.

  The first electrode 51 is made of a metal such as gold, platinum, silver, or titanium. The first electrodes 51 are each connected to the power supply unit 54 via wiring.

  On the other hand, a plurality of nozzles Nz and a second electrode 52 are provided on the ejection surface 110 a of the head 110. A plurality of nozzles Nz are arranged in parallel to the X direction in FIG. 2, and a plurality of such nozzle Nz rows (for example, eight rows in FIG. 2) are provided in the Y direction.

  The second electrode 52 is formed so as to be exposed to the ejection surface 110a, and is disposed around the nozzle Nz. The second electrode 52 is formed using a metal such as gold, platinum, silver, titanium or the like, for example, like the first electrode 51. The second electrode 52 is connected to the power supply unit 54 via wiring or the like.

  The power supply unit 54 can apply a voltage between the first electrode 51 and the second electrode 52, adjust the voltage value, or cancel the application of the voltage under the control of the control device 106, for example. It is like that. Thus, the control device 106 is configured to be able to adjust the voltage between the first electrode 51 and the second electrode 52.

  FIG. 3 is a block diagram illustrating an electrical configuration of the printer 100. The printer 100 includes a control device 106 that controls the operation of the entire printer 100. The control device 106 is connected to an input device IP for inputting various information related to the operation of the printer 100, a storage device MR storing various information related to the operation of the printer 100, and the like. 107, a maintenance mechanism 105, and the like are connected. Further, as described above, the control device 106 controls on / off of voltage application between the second electrode 52 and the first electrode 51 of the head 110, the voltage value, the wiping mechanism 111 of the maintenance mechanism 105, the capping mechanism 112, and the like. It is supposed to be.

Next, a maintenance operation of the head 110 of the printer 100 having the above configuration will be described.
In this embodiment, as a maintenance operation of the head 110, a wiping operation for wiping the ejection surface 110a of the head 110 using the wiping mechanism 111 and removing ink I (see FIG. 4 and the like) adhering to the ejection surface 110a will be described. .

  In this operation, the control device 106 first moves the head 110 to the home position as shown in FIG. Thereafter, as shown in FIG. 5, the control device 106 moves the head 110 to the wiping member 150 side (the −Z side in the drawing), and brings the ejection surface 110 a into contact with the wiping member 150.

  At this time, the control device 106 applies a predetermined voltage between the first electrode 51 inside the wiping member 150 and the second electrode 52 of the head 110. By this operation, as shown in FIG. 5, the second electrode 52 on the ejection surface 110a side and the first electrode 51 on the wiping member 150 side have a potential difference.

  Further, the ink I adhering to the ejection surface 110 a is charged with positive or negative charge by contacting the second electrode 52. The charge charged in the ink I is attracted to the first electrode 51 by the Coulomb force due to the potential difference between the first electrode 51 and the second electrode 52.

  In such a state, as shown in FIG. 6, when the control device 106 moves the head 110 in the + Y direction in the drawing, the ink I attached to the ejection surface 110 a is scraped off by the wiping member 150. At this time, the charged ink I tends to wet and spread on the insulating layer 50. In this manner, the affinity of the insulating layer 50 to the ink I is apparently improved, and the lyophilic property is changed. For this reason, the ink I moves from the ejection surface 110a to the insulating layer 50 and hardly remains on the ejection surface 110a.

  Here, the phenomenon in the present invention will be described. When a voltage is applied between the electrode and the liquid when the electrode is insulated from the conductive liquid by the insulating film connected to the electrode, there is no potential difference between the electrode and the liquid. In comparison, there is a phenomenon that the contact angle between the surface of the insulating film and the liquid is reduced.

  That is, when a voltage is applied between the electrode (first electrode 51) and the liquid (ink I), compared with the case where no potential difference exists between the second electrode 52 and the liquid I, the insulation film ( Insulating layer 50) The liquid repellency of the surface decreases and the wettability increases.

  Therefore, when the ink I comes into contact with the second electrode 52 exposed on the ejection surface 110a and is charged, a potential difference is generated between the first electrode 51 and the surface of the insulating layer 50 is apparently lowered in liquid repellency. , The wettability becomes high and it becomes lyophilic. As a result, the ink I moves toward the insulating layer 50 in contact with the first electrode 51 and hardly remains on the ejection surface 110a. At this time, since the surface of the insulating layer 50 is lyophilic, the ink I scraped off by the wiping member 150 is insulated by the control device 106 moving the head 110 as shown in FIG. It will be retained in layer 50.

  On the other hand, when the application of voltage between the second electrode 52 and the first electrode 51 is released, the above phenomenon does not occur, so that the insulating layer 50 is maintained in a liquid-repellent state. Therefore, for example, as shown in FIG. 8, the ink I hangs down along the surface of the insulating layer 50 of the wiping member 150 by gravity and is removed from the insulating layer 50. Thereby, the cleanliness of the wiping member 150 is maintained.

  As described above, according to the present embodiment, by adjusting the potential of the first electrode 51 provided in the wiping member 150 having the insulating layer 50 formed on the surface, the ink on the surface of the wiping member 150 is adjusted. Since the affinity can be adjusted, the surface of the wiping member 150 can be made lyophilic when the wiping member 150 is used to wipe the ejection surface 110a. Thereby, it is possible to prevent ink from remaining on the ejection surface 110a.

  Moreover, the cleanliness of the wiping member 150 can be maintained by making the surface of the wiping member 150 liquid-repellent after wiping the ejection surface 110a.

The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the control device 106 controls the on / off of the voltage application and the voltage release between the first electrode 51 and the second electrode 52, but the present invention is not limited to this. .

  For example, the first terminal connected to the first electrode 51 is exposed on the surface of the wiping member 150, and the rail-shaped second terminal connected to the power source is disposed on a part of the ejection surface 110 a, so that the wiping member 150 In the wiping operation using, the first terminal may be configured to contact the rail-shaped second terminal.

  In this case, while the wiping member 150 is in contact with the ejection surface 110 a in the wiping operation, the first terminal is in contact with the second terminal, and a voltage is applied between the first electrode 51 and the second electrode 52. Will be. Further, when the wiping operation is finished and the wiping member 150 is separated from the ejection surface 110a, the voltage application is released. In this manner, the application and release of the voltage between the first electrode 51 and the second electrode 52 can be switched in conjunction with the wiping operation.

  In addition, when the wiping member 150 leaves | separates from the injection surface 110a, it is good also as a structure adjusted by the control apparatus 106 so that the voltage between the 1st electrode 51 and the 2nd electrode 52 may not be cancelled | released. Thereby, even when the wiping member 150 moves away from the ejection surface 110a, the ink can be held on the surface of the wiping member 150. Therefore, for example, ink scattering from the wiping member 150 due to the momentum of the wiping operation or the like can be prevented. Can do.

  In the above embodiment, the voltage is continuously applied between the first electrode 51 and the second electrode 52 during the wiping operation, and the voltage application is released after the wiping operation is completed. Although described as an example, it is not limited to this. For example, when the wiping member 150 passes between two rows of nozzles Nz when the wiping member 150 continues to pass through two rows of nozzles Nz different from each other, the first electrode 51 is used. The control device 106 may perform control so that the application of the voltage between the first electrode 52 and the second electrode 52 is canceled and the ink held on the surface of the wiping member 150 is removed. Alternatively, the voltage application between the first electrode 51 and the second electrode 52 is canceled every time the nozzle Nz is passed regardless of the type or color of the ink used in the nozzle Nz row, and the wiping member The control device 106 may perform control so as to remove the ink held on the surface 150.

  When the color or material of the ink is different for each row of nozzles Nz, the above operation causes the wiping member 150 in a state where the ink is removed between the rows of nozzles Nz to pass through the row of nozzles Nz. It is possible to prevent inks of different colors and materials from being mixed. Further, since the ink is wiped off by the wiping member 150 from which the ink has been removed, it is possible to make the ink less likely to remain on the ejection surface 110a.

  Moreover, in the said embodiment, although the structure arrange | positioned so that the 2nd electrode 52 might be exposed to the ejection surface 110a of the head 110 was mentioned as an example, it demonstrated and it was not restricted to this. For example, as shown in FIG. 9, the second electrode 52 may be arranged on the wiping member 150.

  In the configuration shown in FIG. 9, the wiping member 150 has a columnar member 53. The first electrode 51 and the second electrode 52 are provided on the columnar member 53. The first electrode 51 is disposed at the base side (support base 151 side) end of the columnar member 53, and the second electrode 52 is disposed at the upper end of the columnar member 53. The columnar member 53 has a partition portion 53a that partitions the first electrode 51 and the second electrode 52 in the vertical direction.

  The first electrode 51 and the second electrode 52 are electrically insulated by the partition portion 53a. The insulating layer 50 is formed so as to cover the first electrode 51 and is supported by the partition portion 53a. For this reason, the insulating layer 50 is provided at a position away from the second electrode 52. In this state, a voltage is applied so that the first electrode 51 and the second electrode 52 have a potential difference.

  As shown in FIG. 10, when a wiping operation is performed using the wiping member 150 with a voltage applied between the first electrode 51 and the second electrode 52, the surface of the second electrode 52 comes into contact with the ink I. Ink I is charged. For this reason, the charged ink I has a potential difference with the first electrode 51 and is attracted by the Coulomb force, and moves to the insulating layer 50 side.

  In addition, as a structure which provides both the 1st electrode 51 and the 2nd electrode 52 in the wiping member 150, the structure quoted in FIG.9 and FIG.10 is only an example, A structure other than this may be sufficient.

  Moreover, in the said embodiment, although the uniform voltage was applied to the insulating layer 50 from the 1st electrode 51 to the Z direction, it is not restricted to this. For example, the voltage value may be variable in the Z direction of the insulating layer 50. In this case, the degree of lyophilicity in the Z direction of the insulating layer 50 can be varied by adjusting the value of the voltage applied to the insulating layer 50 to be different in the Z direction. As an example of a specific configuration, a configuration in which the first electrode 51 is divided into a plurality of pieces in the Z direction and a voltage can be individually applied to the plurality of first electrodes 51 is exemplified. In this case, the voltage value may be individually adjustable.

  For example, during the wiping operation, the + Z side of the insulating layer 50 can be made lyophilic, and the −Z side of the insulating layer 50 can be made lyophobic. In this case, since the + Z side of the insulating layer 50 is in a lyophilic state, new ink scraped off by the wiping member 150 can be held in the insulating layer 50.

  In addition, the ink held on the −Z side of the insulating layer 50 moves to the −Z side due to gravity, and part of the ink held on the + Z side of the insulating layer 50 flows to the −Z side due to the flow of this ink. Therefore, the ink can be partially removed from the wiping member 150. In this way, the ink removing operation can be performed while performing the wiping operation.

Nz ... Nozzle I ... Ink 50 ... Insulating layer 51 ... First electrode 52 ... Second electrode 54 ... Power supply unit 100 ... Printer 106 ... Control device 110 ... Head 110a ... Ejection surface 111 ... Wiping mechanism 150 ... Wiping member 151 ... Support base

Claims (3)

A liquid ejecting head having an ejecting surface for ejecting liquid;
A wiping portion having an insulating layer formed on the surface and wiping the spray surface;
A first electrode provided inside the wiping unit ;
A second electrode provided on the ejection surface;
By applying a voltage between the first electrode and the second electrode, the surface of the wiping part is made lyophilic with respect to the liquid, and the voltage between the first electrode and the second electrode is A control unit that makes the surface of the wiping unit repellent to the liquid by releasing,
The liquid ejecting head includes a plurality of nozzles provided on the ejecting surface and arranged in a first direction,
A plurality of rows of the nozzles are provided in a second direction intersecting the first direction,
The wiping unit wipes the ejection surface in the second direction;
The control unit applies a voltage between the first electrode and the second electrode when passing through the nozzle row, and the first electrode when moving between the nozzle rows. a liquid ejecting apparatus that to release the application of the voltage between the second electrode. The liquid ejecting apparatus according to claim 1, wherein the wiping portion is formed so that a surface thereof is liquid repellent with respect to the liquid. Wherein, the liquid according to claim 1 or claim 2 front Symbol wiping unit releases the voltage applied between the second electrode and the first electrode when away from the ejection surface Injection device.

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