JP2009012344A - Liquid delivering apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid delivering apparatus in which a simply realizable new measure for preventing viscosity of a first liquid from increasing is carried out. <P>SOLUTION: The liquid delivering apparatus includes a head with nozzles for delivering the first liquid from the nozzles, and a holding body which holds without coming into contact with the head a second liquid in which a nozzle surface of the head is soaked for preventing the viscosity of the first liquid from increasing at the time of non-delivering of the first liquid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid ejection apparatus. In particular, the present invention relates to a liquid ejection apparatus having a nozzle and a head for ejecting a first liquid from the nozzle.

2. Description of the Related Art An ink jet printer as an example of a liquid ejecting apparatus including a nozzle and having a head for ejecting ink as an example of a first liquid from the nozzle is already well known. In such an ink jet printer, a head discharges ink from a nozzle to a medium such as paper being conveyed, thereby forming dots on the medium and printing an image on the medium.
JP 2005-53119 A JP 2001-225484 A

  By the way, when ink is not ejected, the water in the ink tends to evaporate from the meniscus of the nozzle, and the viscosity of the ink increases due to evaporation (thickening). When the viscosity of the ink is increased, the nozzle is likely to be clogged, and there is a possibility that the ink is not ejected or an appropriate amount of ink is not ejected even if the ink is ejected from the nozzle.

  The conventional ink jet printer is provided with a cap for sealing the nozzle in contact with the nozzle surface of the head in order to prevent such ink thickening when ink is not ejected. That is, when ink is not ejected, the cap makes contact with the nozzle surface to form a sealed space in the cap, thereby preventing evaporation of the water from the meniscus, thereby preventing the ink from thickening. It was.

  However, the above-described measures for preventing ink thickening by the cap have the following problems. That is, in order to properly exert the sealing function of the cap (in other words, in order to form an appropriate sealed space in the cap), the cap is surely brought into contact so that no gap is formed on the nozzle surface. There must be. For this purpose, the cap needs to be made with high precision, which has been a factor in the difficulty of manufacturing the cap. In particular, when the head is a line head that is very long in the longitudinal direction of the nozzle surface and very short (very thin) in the short direction of the nozzle surface, the difficulty is even more pronounced. It was. Therefore, there has been a demand for a new ink thickening prevention measure that can be realized more simply than the above measure.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a liquid ejection apparatus in which a new first liquid (for example, ink) thickening prevention measure that can be easily realized is executed. There is to do.

  The main present invention includes a nozzle, a head for discharging the first liquid from the nozzle, and a nozzle surface of the head immersed in order to prevent the first liquid from thickening when the first liquid is not discharged. And a holding body that holds the second liquid without coming into contact with the head.

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

A head including a nozzle for discharging the first liquid from the nozzle, and a second liquid in which the nozzle surface of the head is immersed to prevent thickening of the first liquid when the first liquid is not discharged. And a holding body that holds the head without abutting against the head.
In such a case, a liquid ejection device is provided in which a new first liquid thickening prevention measure that can be easily realized is executed.

The second liquid may be water.
In such a case, since the second liquid can be easily obtained, the new first liquid thickening prevention measure can be more easily realized.

Moreover, it is good also as having a supply part for supplying the said water to the said holding body.
In such a case, it is possible to avoid the nozzle surface from being immersed in the water accommodated in the holder by a simple method.

The second liquid may be a non-volatile oil.
In such a case, since the supply unit or the like is not necessary, the new first liquid thickening prevention measure is more easily realized.

=== Configuration of Printer 1 ===
FIG. 1 is a block diagram of an overall configuration of an ink jet printer (hereinafter also referred to as a printer 1) as an example of a liquid ejection apparatus. Note that the printer 1 according to the present embodiment is not a head that is moved by a carriage, but is called a line printer that uses a head (line head) having a length corresponding to the paper width. Hereinafter, a basic configuration of the printer will be described.

  The printer 1 includes a transport unit 20, a head unit 40, a detector group 50, and a controller 60. The printer 1 that has received the print data from the computer 110 as an external device controls each unit (the transport unit 20 and the head unit 40) by the controller 60. The controller 60 controls each unit based on the print data received from the computer 110 and prints an image on the paper S. The situation in the printer 1 is monitored by a detector group 50, and the detector group 50 outputs a detection result to the controller 60. The controller 60 controls each unit based on the detection result output from the detector group 50.

  The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined transport direction. The transport unit 20 includes a paper feed roller for feeding the paper S inserted into the paper insertion slot into the printer, and a transport for transporting the paper S fed by the paper feed roller to a printable area. It has a roller, a platen 22 (see FIG. 3 and the like) for supporting the paper S being printed, and a paper discharge roller for discharging the paper S to the outside of the printer.

  The head unit 40 includes a head 42 having a plurality of nozzles 44 and an ink thickening prevention device 48 for preventing ink thickening when ink is not ejected.

  The head 42 ejects ink as an example of the first liquid from the nozzle 44 to the paper S being conveyed, thereby forming dots on the paper S facing the head 42 and printing an image on the paper S. As described above, the head 42 according to the present embodiment is a line head, and is a member that is long in the direction orthogonal to the transport direction (that is, the paper width direction) and cannot move in the transport direction. The head 42 can form dots for the paper width at a time.

  FIG. 2 is an explanatory diagram showing the arrangement of the nozzles 44 on the nozzle surface 46 of the head 42 (that is, the lower surface of the head 42). On the nozzle surface 46, a black ink nozzle row K, a cyan ink nozzle row C, a magenta ink nozzle row M, and a yellow ink nozzle row Y are formed. Each nozzle row includes a plurality of nozzles 44, and the plurality of nozzles in each nozzle row are arranged at a constant nozzle pitch along the paper width direction.

  Although details will be described later, the head 42 according to the present embodiment is movable in the vertical direction. That is, the head 42 can be located at either the first position (see FIG. 3) or the second position (see FIG. 4) located below the first position. Move back and forth between the two. Then, when printing is completed and the printer 1 shifts to the standby state so that the ink thickening prevention device 48 can appropriately exhibit the ink thickening prevention function, the first position is changed to the second position (that is, , Move down). The head 42 moves when the rotational force of a motor (not shown) is transmitted to the head 42, and the transmission of the rotational force of the motor to the head 42 is realized by a known transmission mechanism including gears, cams, and the like. Is done. The ink thickening prevention device 48 will be described in detail later.

  The detector group 50 includes various sensors and the like, and a water level sensor 52 described later is also included in the detector group 50.

  The controller 60 is a control unit (control unit) for controlling the printer. The controller 60 includes an interface unit 61, a CPU 62, a memory 63, and a unit control circuit 64. The interface unit 61 transmits and receives data between the computer 110 which is an external device and the printer 1. The CPU 62 is an arithmetic processing unit for controlling the entire printer. The memory 63 is for securing an area for storing a program of the CPU 62, a work area, and the like, and includes storage elements such as a RAM which is a volatile memory and an EEPROM which is a nonvolatile memory. The CPU 62 controls each unit via the unit control circuit 64 in accordance with a program stored in the memory 63.

=== About Ink Thickening Prevention Device 48 ===
As described in the problem to be solved by the invention, in general, an ink jet printer is provided with a function for preventing ink thickening when ink is not ejected. A cap for sealing the nozzle in contact with the nozzle surface is realized. The printer 1 according to the present embodiment is also provided with a function for preventing ink thickening when ink is not ejected. However, the printer 1 is not provided with the cap, and will be described in detail below. The ink thickening prevention device 48 prevents the ink from thickening.

  Hereinafter, the configuration and operation of the ink thickening prevention device 48 according to the present embodiment will be described. This operation is mainly realized by the controller 60 in the printer 1. In particular, in the present embodiment, it is realized by the CPU 62 processing a program stored in the memory 63. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

  3 to 5 are schematic diagrams (conceptual diagrams) showing the ink thickening prevention device 48 and peripheral members (the head 42, the platen 22 and the like) in the vicinity thereof. FIG. 3 is a schematic diagram showing the state of the ink thickening prevention device 48 and peripheral members when the printer 1 is in a printing state (when ink is ejected). FIG. 4 is a schematic diagram showing the state of the ink thickening prevention device 48 and peripheral members when the printer 1 is in a standby state (when ink is not ejected). FIG. 5 is a schematic cross-sectional view taken along the line AA showing the AA cross section of FIG. 4.

  The ink thickening prevention device 48 includes a water tank 400 as an example of a holding body that holds water W as an example of a second liquid, a supply unit 420, a discharge unit 440, and a valve 460.

  As shown in FIG. 4, the water tank 400 is fixed (non-movable) for holding water W in which the nozzle surface 46 of the head 42 is immersed in order to prevent ink thickening when ink is not ejected. ) Member. That is, when the nozzle surface 46 of the head 42 is immersed in the water W held (accommodated) in the water tank 400, the water W suppresses evaporation of water in the ink from the meniscus of the nozzle 44, and increases the ink. Prevent stickiness.

  The water tank 400 has a rectangular parallelepiped shape that is long (see FIG. 5) in a direction orthogonal to the transport direction (that is, the paper width direction), and a portion corresponding to the upper surface of the rectangular parallelepiped has an opening 400a. As shown in FIGS. 3 and 4, the water tank 400 is provided between the platens 22 described above in the transport direction, and is provided at a position corresponding to the position of the head 42. That is, the platen 22 is provided with a groove 22a along the paper width direction (in other words, the longitudinal direction of the nozzle surface 46 of the head 42) at a position corresponding to the position of the head 42 in the transport direction. The water tank 400 is provided in the groove 22a. The water tank 400 is located below the upper surface 22b of the platen 22 in the groove 22a (more specifically, the uppermost part of the water tank 400 is located below the upper surface 22b). .

  The relative positional relationship between the head 42 and the water tank 400 in the vertical direction differs between when the printer 1 is in the printing state and when it is in the standby state. That is, as shown in FIG. 3, when the printer 1 is in a printing state, the head 42 is moved from the upper surface 22 b of the platen 22 so that ink is appropriately ejected from the nozzles 44 of the head 42 onto the paper S being conveyed. The water tank 400 is located at a position away from the head 42 in the vertical direction. Then, when the printer 1 shifts from the printing state to the standby state, the head 42 moves downward. As shown in FIG. 4, when the printer 1 is in the standby state, the water tank 400 is located at a position closer to the head 42 in the vertical direction (the head 42 is located at the second position). The nozzle surface 46 of the head 42 is immersed in water W stored in the water tank 400 in order to prevent ink thickening when ink is not ejected.

  As shown in FIG. 4, in the short direction of the nozzle surface 46, one end E1 of the liquid surface WS of the water W is located outside the one end E2 of the nozzle surface 46, and other than the liquid surface WS. The end E3 is located outside the other end E4 of the nozzle surface 46. Further, as shown in FIG. 5, in the longitudinal direction of the nozzle surface 46, one end E5 of the liquid surface WS is located outside the one end E6 of the nozzle surface 46, and the other end E7 of the liquid surface WS is the nozzle It is located outside the other end E8 of the surface 46. That is, the water tank 400 that holds the water W is not in contact with the head 42, and therefore the water tank 400 contains the water W in which the nozzle surface 46 is immersed to prevent ink thickening when ink is not ejected. The head 42 is held without contacting.

  Further, the printer 1 according to the present embodiment has a function of maintaining the height of the liquid level WS (in other words, the water level of the water W) at a constant value. That is, the water level of the water W stored in the water tank 400 may change due to evaporation of the water W or the like as the printer 1 is used unless any countermeasure is taken. And if the said water level changes, there exists a possibility that the nozzle surface 46 may not be immersed in the water W accommodated in the water tank 400. FIG. Therefore, the printer 1 according to the present embodiment is provided with this function so that such inconvenience does not occur.

  As shown in FIG. 4, the printer 1 has a supply tank 420a and a supply flow path 420b, and has a supply unit 420 positioned above the water tank 400, a discharge tank 440a, and a discharge flow path 440b. The water tank 400 is connected to each of the supply unit 420 and the discharge unit 440. The discharge unit 440 is provided below the water tank 400. Then, due to the action of gravity, water is supplied from the supply section 420 (more specifically, from the supply tank 420a via the supply flow path 420b) to the water tank 400, and from the water tank 400 to the discharge section 440 (more specifically, The water is discharged to the discharge tank 440a through the discharge channel 440b. Further, a supply side valve 460a and a discharge side valve 460b are provided as valves 460 in the supply flow path 420b and the discharge flow path 440b, respectively.

  Further, the printer 1 is provided with a water level sensor 52 (FIG. 1) as an example of a sensor, and the height of the liquid level WS is detected by the water level sensor 52. Then, based on the detection result of the water level sensor 52, the height of the liquid surface WS is adjusted so that the height of the liquid surface WS becomes a preset target value.

  More specifically, when the water level sensor 52 detects the height of the liquid level WS, the detected value is sent to the controller 60. Then, the controller 60 compares the detected value with the target value, and if the detected value is smaller than the target value (if the detected liquid level WS is lower than the target value), the supply side valve 460a The supply side valve 460a is controlled so as to be in the open state. When the supply side valve 460a is opened, water is supplied from the supply tank 420a to the water tank 400, the liquid level WS rises, and the height of the liquid level WS approaches the target value.

  Conversely, the controller 60 compares the detected value with the target value, and if the detected value is larger than the target value (if the detected liquid level WS is higher than the target value), the discharge side valve The discharge side valve 460b is controlled so that 460b is in the open state. When the discharge side valve 460b is opened, water is discharged from the water tank 400 to the discharge tank 440a, the liquid level WS is lowered, and the height of the liquid level WS approaches the target value.

  When the height of the liquid level WS falls within the range of the target value ± δ (allowable value), the controller 60 assumes that the height of the liquid level WS has reached the target value, and the valve 460 that has been opened. The valve 460 is controlled so that is closed. With this control, the valve 460 is closed.

  As described above, the controller 60 and the valve 460 (the supply side valve 460a and the discharge side valve 460b) described above function as an adjustment unit for adjusting the height of the liquid level WS. And the said adjustment part adjusts the height of the liquid level WS as mentioned above based on the detection result of the water level sensor 52, and, thereby, the height of the liquid level WS is maintained at a fixed value. It becomes. In the printer 1 according to the present embodiment, such adjustment is periodically performed. However, the adjustment is not limited thereto, and for example, the adjustment may be constantly performed.

=== Effectiveness of Printer 1 According to the Present Embodiment ===
As described in the section of the problem to be solved by the invention, in the conventional inkjet printer, in order to prevent ink thickening when ink is not ejected, the nozzle is sealed in contact with the nozzle surface of the head. Cap was provided. That is, when the ink is not ejected, the cap contacts the nozzle surface to form a sealed space in the cap, thereby preventing evaporation of water in the ink from the meniscus, thereby increasing the viscosity of the ink. It was preventing.

  However, the above-described measures for preventing ink thickening by the cap have the following problems. That is, in order to properly exert the sealing function of the cap (in other words, in order to form an appropriate sealed space in the cap), the cap is surely brought into contact so that no gap is formed on the nozzle surface. For that purpose, the cap had to be made with high precision. This has been a factor in the difficulty of manufacturing the cap. In particular, when the head is a line head that is very long in the longitudinal direction of the nozzle surface and very short (very thin) in the short direction of the nozzle surface, the difficulty becomes more remarkable. . Accordingly, there has been a demand for a new ink thickening prevention measure that can be realized more simply than the above measure.

  On the other hand, the printer 1 according to the present embodiment satisfies such a request. That is, the printer 1 includes a water tank 400 that holds water W in which the nozzle surface 46 of the head 42 is immersed without contacting the head 42 in order to prevent ink thickening when ink is not ejected. . The nozzle surface 46 of the head 42 is immersed in the water W held in the water tank 400 so that the water tank 400 does not contact the head 42 (that is, the water tank 400 seals the nozzle 44 and seals the sealed space). Even if the ink is not formed, the evaporation of water in the ink from the meniscus of the nozzle 44 is suppressed, and the thickening of the ink is appropriately prevented. Further, since there is no need to bring the water tank 400 into contact with the head 42, the water tank 400 does not have to be made with high accuracy like a cap, and thus the above-described manufacturing difficulty does not occur. As described above, according to the printer 1 according to the present embodiment, the ink thickening prevention measure that can be easily realized is executed.

  Further, since the head 42 provided in the printer 1 according to the present embodiment is a line head, it is very long in the longitudinal direction of the nozzle surface 46. Therefore, in order to make the cap contact with the head 42 from one end in the longitudinal direction to the other end without any gap, the cap needs to be made with extremely high accuracy. On the other hand, in the printer 1 according to the present embodiment, since the water tank 400 does not contact the head 42, there is no need to worry about such matters.

  Moreover, since the head 42 provided in the printer 1 according to the present embodiment is a line head, it is very short (very thin) in the short direction of the nozzle surface. Therefore, in order to bring the cap into contact with the head 42, it is necessary to reduce the size of the cap, which makes it difficult to manufacture. On the other hand, in the printer 1 according to the present embodiment, since the water tank 400 does not contact the head 42, it is not necessary to reduce the size of the water tank 400 according to the thinness of the head 42.

=== Other Embodiments ===
The liquid ejection apparatus according to the present invention has been described above based on the above embodiment. However, the above-described embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. Absent. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes the equivalents thereof.

  In the above-described embodiment, the ink jet printer has been described as an example of the liquid ejection device. However, the present invention is not limited to this, and the liquid other than the ink (a liquid in which functional material particles are dispersed, It can also be embodied in a liquid ejecting apparatus that ejects or ejects a fluid (including a fluid such as a gel). For example, a liquid material ejecting apparatus that discharges a liquid material in the form of dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays, and biochip manufacturing It may be a liquid ejecting apparatus for ejecting a bio-organic substance used in the above, or a liquid ejecting apparatus for ejecting a liquid as a sample used as a precision pipette. In addition, a transparent resin liquid such as UV curable resin is used to form a liquid ejection device that ejects lubricating oil pinpoint to precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. A liquid discharge device that discharges a liquid onto the substrate, a liquid discharge device that discharges an etching solution such as acid or alkali to etch the substrate, and a fluid discharge device that discharges gel. The present invention can be applied to any one of these discharge devices.

  Moreover, in the said embodiment, although the line head was mentioned as an example and demonstrated as a head, it is not limited to this. For example, a serial head provided on a carriage and moving in the paper width direction as the carriage moves may be used.

  Moreover, although the printer 1 according to the above-described embodiment includes the supply unit 420 for supplying water to the water tank 400, the present invention is not limited to this. For example, such a supply unit 420 may not be provided in the printer 1.

  As described above, the water W stored in the water tank 400 evaporates as the printer 1 is used, and the water level can be gradually lowered. When the supply unit 420 is not provided in the printer 1 and water is not supplied to the water tank 400, the nozzle surface 46 may not be immersed in the water W stored in the water tank 400. It is necessary to take measures. As a countermeasure against this, a measure for changing the above-described second position of the head 42 in accordance with the change (down) of the water level can be considered, but in such a case, the moving mechanism of the head 42 becomes extremely complicated.

  On the other hand, if the printer 1 is provided with the supply unit 420 and water is supplied from the supply unit 420 to the water tank 400, the nozzle surface 46 can be prevented from being immersed in the water W stored in the water tank 400. Can be avoided. Therefore, in this respect, the above-described embodiment is more desirable (although not limited to the above-described embodiment and may be the other measure).

  In addition, the printer 1 according to the above embodiment has a water level sensor 52 for detecting the height of the liquid level WS of the water W, and the height of the liquid level WS based on the detection result of the water level sensor 52. The adjustment unit (the controller 60 and the valve 460) for adjustment is included, but is not limited thereto. For example, the printer 1 may not include the water level sensor 52 or the adjustment unit.

  As a measure for preventing the nozzle surface 46 from being immersed in the water W accommodated in the water tank 400 without providing the printer 1 with the water level sensor 52 or the adjusting part, the water tank 400 is supplied with water from the supply part 420. Can be considered as a means of supplying However, since the degree of water evaporation is not constant (because it changes dynamically depending on the day and time), such a measure does not surely prevent the nozzle surface 46 from being immersed in the water W accommodated in the water tank 400. It's hard to say.

  On the other hand, if the printer 1 is provided with a water level sensor 52 and an adjustment unit and the height of the liquid level WS is adjusted based on the detection result of the water level sensor 52, the water W stored in the water tank 400 is stored in the water surface W. It is possible to reliably prevent the occurrence of a situation where it is not soaked. Therefore, in this respect, the above embodiment is more desirable (although not limited to the above embodiment and may be the above-described method).

  Moreover, in the said embodiment, although water W was mentioned as an example and demonstrated as a 2nd liquid, it is not limited to this. For example, the second liquid may be another liquid such as oil.

  When the second liquid is water W, the second liquid can be easily obtained, so that the ink thickening prevention device 48 can be constructed more easily. That is, a new first liquid thickening prevention measure can be realized more easily. In this respect, the above embodiment is preferable.

  Further, when the second liquid is oil and the oil is a non-volatile oil, the following merits occur. That is, when the second liquid is a non-volatile oil, the second liquid does not evaporate, and the height of the liquid level does not change. Therefore, the ink thickening prevention device can be constructed more easily, and therefore, a new first liquid thickening prevention measure can be realized more simply.

In the above embodiment, when the printer 1 shifts from the printing state to the standby state, the head 42 moves downward to immerse the nozzle surface 46 in the water W stored in the water tank 400. However, it is not limited to this, For example, it is good also as the water tank 400 moving upwards.
However, the above embodiment is more preferable in that the disadvantage that the water W spills from the water tank 400 does not occur.

1 is a block diagram of an overall configuration of a printer 1. FIG. FIG. 4 is an explanatory diagram showing the arrangement of nozzles 44 on the nozzle surface 46 of the head 42. FIG. 6 is a schematic diagram showing the state of the ink thickening prevention device 48 and peripheral members when the printer 1 is in a printing state (during ink ejection). FIG. 6 is a schematic diagram showing the state of the ink thickening prevention device and peripheral members when the printer is in a standby state (when ink is not ejected). It is the AA cross-sectional schematic diagram showing the AA cross section of FIG.

Explanation of symbols

1 printer,
20 transport unit, 22 platen, 22a groove, 22b upper surface,
40 head units, 42 heads, 44 nozzles, 46 nozzle surfaces,
48 ink thickening prevention device, 50 detector group, 52 water level sensor,
60 controller, 61 interface unit, 62 CPU,
63 memory, 64 unit control circuit, 110 computer,
400 water tank, 400a opening, 420 supply part,
420a supply tank, 420b supply flow path,
440 discharge section, 440a discharge tank, 440b discharge flow path,
460 valve, 460a supply side valve, 460b discharge side valve

Claims (4)

A nozzle, and a head for discharging the first liquid from the nozzle;
A second liquid in which the nozzle surface of the head is immersed to prevent thickening of the first liquid when the first liquid is not discharged;
A holding body that holds without contacting the head,
A liquid ejecting apparatus comprising: The liquid ejection apparatus according to claim 1,
The liquid ejection apparatus, wherein the second liquid is water. The liquid ejection apparatus according to claim 2, wherein
A liquid discharge apparatus comprising a supply unit for supplying the water to the holding body. The liquid ejection apparatus according to claim 1,
The liquid ejection apparatus, wherein the second liquid is a non-volatile oil.

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