JP2017030198A - Device of discharging liquid, medium holding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device of discharging liquid capable of assuring cleanliness if an aqueous liquid and an oily liquid are used and even if a liquid that is discharged to an idle discharge region is an oily liquid.SOLUTION: At three points on a peripheral surface of a medium holding member 10, idle discharge regions 51-53 which are used when an idle discharge liquid that does not contribute to image formation is discharged from liquid discharge heads 21-26 are disposed. The nature of a surface in at least two idle discharge regions among the idle discharge regions 51-53 has a different characteristic not to allow a liquid to fit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for discharging a liquid and a medium holding member.

  In an apparatus for ejecting liquid, which includes liquid ejecting means for ejecting liquid onto a medium, an empty ejected liquid having a purpose other than the main purpose of the apparatus for maintaining and recovering the state of a nozzle of a liquid ejecting head which is a liquid ejecting means An empty discharge operation for discharging (droplets) is performed. Note that idle ejection includes ejection that is also referred to as flushing or preliminary ejection.

  2. Description of the Related Art Conventionally, it is known to apply a coating liquid such as silicone oil having a property of repelling ink to an opposing member in order to improve cleanability when ink droplets adhere to the opposing member such as a conveyance belt that conveys a medium. (Patent Document 1).

JP 2007-301930 A

  By the way, when using, for example, an aqueous liquid and an oily liquid as the liquid discharged from the liquid discharge means, the cleaning of the empty discharged liquid is facilitated in the case of an aqueous liquid only with the configuration disclosed in Patent Document 1. However, in the case of an oily liquid, there is a problem that the cleaning property is lowered.

  The present invention has been made in view of the above-described problems, and an object thereof is to ensure cleanability even when the types of liquids are different.

In order to solve the above problems, an apparatus for ejecting a liquid according to the present invention includes:
Liquid ejection means for ejecting liquid;
A medium holding member for holding a medium to which the liquid is attached,
On the surface of the medium holding member, there are at least two empty discharge regions that receive the empty discharge liquid discharged from the liquid discharge means,
The two empty ejection regions have different surface properties.

  According to the present invention, cleanability can be secured even if the type of liquid is different.

It is a schematic explanatory drawing of an example of the apparatus which discharges the liquid which concerns on 1st Embodiment of this invention. It is explanatory drawing of the medium holding member with which it uses for description of 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of a device for ejecting liquid according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view of the apparatus.

  This apparatus includes a medium holding member 10 that holds a medium 40 in the apparatus main body 1. The medium holding member 10 is a drum-shaped rotating body, and rotates in the counterclockwise direction (arrow A direction) in FIG.

  A gripper 30 that grips the tip of the medium 40 is provided on the peripheral surface of the medium holding member 10. The grippers 30 are provided at a plurality of locations on the peripheral surface in the rotation direction of the medium holding member 10.

  Then, the medium 40 supplied by the pair of conveying rollers 81 and 82 is sandwiched between the grippers 30 of the medium holding member 10 and rotated in the arrow A direction so that the medium 40 is conveyed by the medium holding member 10. .

  A liquid ejection means 2 that ejects liquid at a required position is disposed opposite to the circumferential surface of the medium holding member 10.

  In the liquid ejecting means 2, liquid ejecting heads 21 to 26 are arranged along the rotation direction of the medium holding means 10. The liquid discharge heads 21 to 24 discharge, for example, black, cyan, magenta, and yellow liquids. The liquid discharge heads 25 and 26 discharge different types of coating liquids (processing liquids) to the medium 40 on which an image is formed, for example.

  While the medium holding member 10 rotates in the direction of arrow A and moves relative to the liquid ejecting means 2 to transport the medium 40, the medium 40 is ejected from the liquid ejecting heads 21 to 24 by discharging a liquid of a required color. A required image is formed. If necessary, the processing liquid is discharged from the liquid discharge heads 25 and 26 to coat the image.

  In this way, the medium 40 held and conveyed by the medium holding member 10 is separated by the separation member 71 after the predetermined image is formed by the liquid ejecting means 2, and the paper discharge is reversed connected to the apparatus main body 1. It is sent to unit 3.

  The paper discharge reversing unit 3 includes a paper discharge belt unit 72 including a belt that conveys the medium 40, a drying unit 73 that dries the medium 40 conveyed by the paper discharge belt unit 72, a conveyance path switching member 74, and a paper discharge. A reverse conveyance belt unit 76 including a roller pair 75 and a belt for conveying the medium 40 is provided.

  Then, by switching the transport path switching member 74, the medium 40 sent from the paper discharge belt unit 72 is transported in the direction of arrow B and discharged through the pair of paper discharge rollers 75, or transported in the direction of arrow C. It can be sent out on the reverse conveying belt unit 76.

  The medium 40 sent to the reverse conveyance belt unit 76 is conveyed to the apparatus main body 1 side by the reverse conveyance belt unit 76, is taken into the apparatus main body 1 by the paper feed roller pair 77, and is placed on the peripheral surface of the medium holding member 10. Sent and re-fed.

  Then, the medium 40 re-fed to the medium holding member 10 is held with the leading end being sandwiched and held by the gripper 30, transported with the back side as the printing surface, and an image is formed on the back side, and then discharged. The paper is discharged from the paper discharge roller pair 75 through the paper reversing unit 3.

  In this apparatus, empty discharge areas 51 to 53 used for discharging empty discharge liquid that does not contribute to image formation from the liquid discharge heads 21 to 26 are arranged at three locations on the peripheral surface of the medium holding member 10. . Here, the idle ejection regions 51 to 53 are arranged corresponding to the three grippers 30 and are separated from each other in the rotation direction (movement direction) of the medium holding member 10. Note that the number of idle ejection regions may be at least two, and may be four or more.

  At least two of the empty discharge regions 51 to 53 have different characteristics in terms of surface properties so that the liquid does not adhere. For example, the surface properties of the idle ejection region 51 and the idle ejection region 53 are different.

  On the other hand, the apparatus main body 1 holds the relationship between the characteristics or types of each liquid scheduled to be used and the empty discharge areas 51 to 53 for discharging the empty discharge liquid of the liquid, for example, in a table form. .

  Further, a cleaning unit 60 is provided for cleaning and removing the liquid (empty discharge liquid) adhering to the empty discharge regions 51 to 53 of the medium holding member 10.

  The cleaning means 60 is, for example, a cleaner around which the web 61 is wound. The cleaning means 60 is disposed so as to be movable in the direction of arrow D between a position where the web 61 contacts the circumferential surface of the medium holding member 10 and a position where the web 61 is separated from the circumferential surface of the medium holding member 10. The web 61 is wound while moving in the direction of arrow E. The cleaning means 60 may be a scraper such as a rubber spatula.

  With this configuration, when discharging the empty discharge liquid that does not contribute to image formation from the liquid discharge heads 21 to 26, the empty discharge areas 51 to 53 having a surface property that the empty discharge liquid does not adhere or is difficult to adhere. Either of these is selected and the empty discharge liquid is discharged. For example, as described above, it can be easily selected to form a table.

  For example, the idle ejection region 51 is coated with silicone oil and has water repellency as liquid repellency. The empty discharge region 53 is, for example, chrome-plated and has hydrophilicity as a lyophilic property. That is, with respect to the cleaning means 60, the idle discharge area 51 on the upstream side in the rotation direction (movement direction) of the medium holding member 10 is made liquid repellent, and the empty discharge area 53 on the downstream side in the rotation direction is made lyophilic.

  The empty discharge area 52 can be water repellency or hydrophilicity that is not as strong as the empty discharge area 51 or the empty discharge area 53.

  In this case, when the empty discharge liquid is a water-based ink or an aqueous coating liquid (hereinafter referred to as “aqueous liquid”), the empty discharge area 51 is attached to the surface of the empty discharge area 51 by performing the empty discharge. Even if the empty discharge liquid is dried or thickened, it is difficult to adhere to the empty discharge region 51. Therefore, the empty discharge liquid adhering to the empty discharge area 51 can be easily wiped off by the cleaning means 60.

  Further, when the idle discharge liquid is oil-based ink or oil-based coating liquid (hereinafter referred to as “oil-based liquid”), the idle discharge attached to the surface of the idle discharge area 53 is performed by performing idle discharge on the idle discharge area 53. Even if the discharge liquid is dried or thickened, it becomes difficult to adhere to the empty discharge region 53. Therefore, the empty discharge liquid adhering to the empty discharge region 53 can be easily wiped off by the cleaning means 60.

  As described above, the empty discharge liquid is discharged to any one of the empty discharge areas 51 to 53 having a surface property (surface state) where the empty discharge liquid is not fixed or difficult to be fixed. It can be removed and the empty discharge area can be easily cleaned.

  Accordingly, even when a plurality of liquids having different fixing characteristics are used, the empty discharge region can be easily cleaned, and the cleanability can be ensured even if the types of liquids are different.

  Here, description will be given of water repellency imparting water repellency as liquid repellency, imparting water repellency to the empty ejection region of the medium holding member, and the like.

  Examples of the water-repellent material include the following materials.

  Polybutylene terephthalate, polyethylene, tetrafluoroethylene / perfluoroalkoxyethylene copolymer resin, polyacetal, polypropylene, polytetrafluoroethylene, polyvinyl chloride, phenol resin, modified polyphenylene ether, modified polyphenylene oxide, polycarbonate, ethylene propylene rubber, Silicon rubber, nitrile rubber, chloroprene rubber, polyphenylene sulfide, polyvinylidene fluoride, ethylene tetrafluoride / hexafluoropropylene copolymer resin, tetrafluoroethylene / ethylene copolymer resin.

  These can impart water repellency by forming a film on the surface of the peripheral surface of the medium holding member 10. As a method for forming the film, a generally used method can be employed. For example, in the case of a liquid paint, spray coating, dip coating, roll coating and the like can be mentioned. In the case of a powder paint, electrostatic powder coating, electrostatic dipping method, dip dipping method and the like can be mentioned.

  It is preferable that the surface of the empty discharge region of the medium holding member 10 to which these resin materials are applied is preliminarily roughened by forming an uneven surface on the surface by thermally spraying ceramic. As a result, the resin material applied to the surface of the medium holding member 10 is filled so as to bite into the recesses to form a film, so that the film of the resin material bites the surface of the medium holding member 10. And the durability of the film becomes excellent.

  In addition, even if a metal having water repellency such as titanium is provided on the surface of the idle discharge region of the medium holding member 10, the surface can be made water repellant similarly.

  Here, it is preferable that the water contact angle of the empty discharge region having water repellency is 70 ° or more, and more preferably 90 ° or more.

  Here, as a method for measuring the contact angle, “New Experimental Chemistry Course 18 Interface and Colloid” on page 97, using a flat specimen obtained with the same material and forming method as the surface of the empty ejection region of the medium holding member 10 ( Measured based on the droplet method using the contact angle measurement method published on Mar. 20, 1977. The contact angle can generally be measured with a reading microscope (approximately 20 times magnification) equipped with a goniometer.

  Next, hydrophilic property imparting hydrophilicity as a lyophilic property and imparting hydrophilic property to the empty ejection region of the medium holding member will be described.

  In order to impart hydrophilicity, for example, a vapor-deposited film having excellent hydrophilicity made of carbide, nitride, or carbonitride of Ti, Cr, Al, Si, Zr, and B is formed. Examples of the method for forming the vapor deposition film include sputtering vapor deposition, ion plating vapor deposition, and electron beam vapor deposition.

  Further, the idle discharge region of the medium holding member 10 can be formed of a highly hydrophilic metal surface such as aluminum, stainless steel, or iron, or chrome plating or nickel plating can be applied to these metal surfaces. In addition, if the medium holding member 10 is aluminum, it is subjected to water vapor treatment (boehmite treatment) or alumite treatment to increase the hydrophilic treatment, or is formed of a hydrophilic plastic such as hydrophilic rubber or nylon, and is made of metal or plastic. It can also be coated with gum arabic.

  Further, the medium holding member 10 can also be constituted by a rubber roller containing a surfactant. The surfactant can dissolve in water or oil to significantly reduce the interfacial energy, reduce the contact angle with the ink, and make the surface hydrophilic. For such a rubber, for example, ethylene propylene diene rubber, polynorbornene rubber, chlorinated polyethylene rubber or the like having a relatively low hardness is suitable.

  Furthermore, the surface of the empty discharge region of the medium holding member 10 can be covered with glass or glazing, or the medium holding member 10 itself can be formed with glass or glazing. Glass and wrinkles are highly hydrophilic, and can work to reduce the contact angle with ink as described above, making the surface hydrophilic.

  When the entire surface of the medium holding member 10 has hydrophilicity, a process for imparting water repellency to the empty ejection region to be given water repellency may be performed. On the other hand, when the entire surface of the medium holding member 10 has water repellency, a process of imparting hydrophilicity to the empty ejection region to be hydrophilic may be performed. That is, the idle ejection region is not limited to a region having a property different from the surface property of the medium holding member 10 itself, and means a region to which the idle ejection liquid is attached.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory view of a medium holding member for explaining the embodiment.

  The idle ejection area 51 is divided into three idle ejection areas 51 a, 51 b, 51 c from the upstream side in the rotation direction of the medium holding member 10. That is, the plurality of idle ejection regions 51a to 51c are arranged adjacent to each other in the rotation direction.

  In the present embodiment, the number of idle ejection regions may be two or more, and may be four or more. Also, the idle ejection regions 52 and 53 can be divided in the same manner as the idle ejection region 51. In this case, the number of divided empty discharge areas in the empty discharge areas 51 to 53 may be the same or different.

  For example, the idle ejection region 51a is coated with silicone oil and has liquid repellency (water repellency). The empty discharge area 51c is, for example, chrome-plated and has lyophilicity (hydrophilicity). That is, the empty discharge area upstream of the medium holding member 10 in the rotation direction with respect to the cleaning unit 60 is made liquid repellent, and the empty discharge area downstream of the rotation direction is made lyophilic.

  In this case as well, the empty discharge region 51b can be water repellency or hydrophilicity that is not as strong as the empty discharge region 51a or the empty discharge region 51c.

  In this case, when the empty discharge liquid is an aqueous liquid, the empty discharge liquid attached to the surface of the empty discharge area 51a is dried or thickened by performing the empty discharge on the empty discharge area 51a. However, it is difficult to adhere to the empty ejection region 51a. Therefore, the empty discharge liquid adhering to the empty discharge area 51a can be easily wiped off by the cleaning means 60.

  Further, when the empty discharge liquid is an oily liquid, the empty discharge liquid adhered to the surface of the empty discharge area 51c is dried or thickened by performing the empty discharge on the empty discharge area 51c. However, it becomes difficult to adhere to the idle ejection region 51c. Therefore, the empty discharge liquid adhering to the empty discharge area 51 c is easily wiped off by the cleaning means 60.

  As described above, the empty discharge liquid is discharged to any one of the empty discharge regions 51a to 51c having a surface state where the empty discharge liquid is not fixed or difficult to be fixed. The empty discharge area can be easily cleaned.

  Further, by disposing adjacent empty discharge regions having different surface properties as in the present embodiment, it is possible to face the empty discharge regions corresponding to the empty discharge liquid in a short time. That is, the empty discharge area corresponding to the empty discharge liquid can be moved to a position facing the liquid discharge means in a short time.

  Next, a third embodiment of the present invention will be described.

  In the present embodiment, in the empty discharge regions 51a to 51c of the medium holding member of the second embodiment, the empty discharge region 51a has water repellency, and the empty discharge regions 51b and 51c have hydrophilicity.

  Then, when the empty discharge liquid is an aqueous liquid, empty discharge is performed on the empty discharge regions 51b and 51c.

  As a result, even if the medium holding member 10 rotates at a high speed, the liquid ejected idle does not leave the peripheral surface of the medium holding member 10 until it reaches the cleaning means 60. And when wiping with the cleaning means 60, if it reaches the upstream empty discharge area 51a by being pushed by the cleaning means 60 without being wiped in the downstream empty discharge areas 51b and 51c, it is wiped there. It becomes easier and less wiping can be left.

  Here, if the boundary between the hydrophilic region and the water-repellent region is clearly divided, the aqueous liquid moved from the hydrophilic region to the water-repellent region may be scattered.

  Therefore, in this case, the boundary portion between the hydrophilic region and the water repellent region is gradually changed from hydrophilic to water repellent. Thereby, it can wipe off, without scattering.

  Next, a fourth embodiment of the present invention will be described.

  In the present embodiment, in the empty discharge areas 51a to 51c of the medium holding member of the second embodiment, the empty discharge area 51a has hydrophilicity (oil repellency), and the empty discharge area 51a has water repellency (lipophilicity). Have.

  Then, when the empty discharge liquid is an oily liquid, the empty discharge is performed on the empty discharge regions 51b and 51c.

  As a result, even if the medium holding member 10 rotates at a high speed, the liquid ejected idle does not leave the peripheral surface of the medium holding member 10 until it reaches the cleaning means 60. And when wiping with the cleaning means 60, if it reaches the upstream empty discharge area 51a by being pushed by the cleaning means 60 without being wiped in the downstream empty discharge areas 51b and 51c, it is wiped there. It becomes easier and less wiping can be left.

  Again, if the boundary between the water-repellent region (lipophilic region) and the hydrophilic region (oil-repellent region) is clearly separated, the oily liquid moved from the water-repellent region (lipophilic region) to the hydrophilic (oil-repellent region) May scatter.

  Therefore, in this case, the boundary portion between the water-repellent region (lipophilic region) and the hydrophilic region (oil-repellent region) is gradually changed from water-repellent (lipophilic) to hydrophilic (oil-repellent). Thereby, it can wipe off, without scattering.

  In the above-described embodiment, the example in which the medium holding member is a drum-like rotating body has been described. For example, it may be a belt-like rotating body that moves around. Further, although the medium holding member is described as being configured to rotate while holding the medium, the medium holding member may be configured to advance and retreat without rotating, and the medium holding part suppository does not move and the liquid The ejection unit may move relative to the medium holding member.

1 Device body 1
DESCRIPTION OF SYMBOLS 2 Liquid discharge means 3 Paper discharge reversal unit 10 Medium holding member 21-27 Liquid discharge head 51-53 Empty discharge area 51a, 51b, 51c Empty discharge area 60 Cleaning means

Claims (9)

Liquid ejection means for ejecting liquid;
A medium holding member for holding a medium to which the liquid is attached,
On the surface of the medium holding member, there are at least two empty discharge regions that receive the empty discharge liquid discharged from the liquid discharge means,
An apparatus for ejecting liquid, wherein the two empty ejection regions have different surface properties. The apparatus for ejecting liquid according to claim 1, wherein the two empty ejection regions are spaced apart from each other. The apparatus for ejecting liquid according to claim 1, wherein the two empty ejection regions are arranged adjacent to each other. In the relative movement direction of the medium holding member with respect to the liquid ejection means,
4. The idle discharge area on the downstream side of the two idle discharge areas is lyophilic, and the empty discharge area on the upstream side is lyophobic. A device for discharging the liquid according to any one of the above. In the relative movement direction of the medium holding member with respect to the liquid ejection means,
4. The idle discharge area on the downstream side of the two empty discharge areas has liquid repellency, and the empty discharge area on the upstream side has lyophilicity. A device for discharging the liquid according to any one of the above. The gradual change from lyophilic to lyophobic at a boundary portion between the downstream idle discharge area and the upstream idle discharge area in the moving direction of the two idle discharge areas. Item 5. A device for discharging the liquid according to Item 4. The gradual change from lyophobic to lyophilic at a boundary portion between a downstream idle discharge area and an upstream idle discharge area in the moving direction of the two idle discharge areas. Item 6. A device for discharging the liquid according to Item 5. The apparatus for discharging a liquid according to claim 1, further comprising a cleaning unit that cleans the empty discharge region. A medium holding member for holding a medium to which a liquid discharged from the liquid discharging means is attached;
On the surface of the medium holding member, there are at least two empty discharge areas that receive the empty discharge liquid discharged from the liquid discharge means,
The medium holding member, wherein the two empty ejection regions have different surface properties.

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