JP2010214804A - Liquid jet recording method and recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain good metallic gloss in a method for recording by jetting a photo-curable liquid. <P>SOLUTION: The liquid jet recording method comprises: forming dots by jetting onto a medium a liquid to be cured upon irradiation with light and containing a metallic pigment; exerting an electric field on the dots; and irradiating the dots exerted with the electric field with light. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid jet recording method and a recording apparatus.

  There is known an ink composition that is capable of producing a recorded matter having a metallic luster and is excellent in recording stability and fixability on a recording medium. In such an ink, a metallic foil piece having a predetermined particle size, particle size distribution, and the like is contained as a pigment to enable recording with metallic luster (see Patent Documents 1 to 3).

  Also, an ink jet recording method using an ink composition having a metallic luster, focusing on aluminum as a metal pigment (see Patent Document 4), and an ink set capable of forming a coating film having a metallic luster of any color tone (See Patent Document 5). Furthermore, an ink jet recording method is known in which an image is formed using an ink set including a metallic ink composition containing a metal pigment and a photocurable ink (see Patent Document 6).

JP2007-46034 JP2007-131741 JP2007-169451 JP 2008-174712 A JP2008-208330 JP2008-239951

  In a jet recording method using a photocurable liquid, a method is conceivable in which a metal foil piece is contained as a pigment in the liquid, and the metal pigment reflects light to obtain a metallic luster on the recording surface.

However, in this method, the metallic pigment in the liquid that has landed on the medium diffuses the light, and thus a metal luster having a sufficient texture cannot be obtained.
An object of the present invention is to obtain a high-quality metallic luster in a method for recording by jetting a photocurable liquid.

  The main invention for achieving the above object is a liquid that cures when irradiated with light, and forms a dot by ejecting a liquid containing a metal pigment onto a medium, and applies an electric field to the dot. And irradiating light to the dots acted on by the electric field.

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

It is a figure which shows distribution of the metal pigment in a dot. It is a figure which shows distribution of the metal pigment in the dot at the time of applying an electric field. It is a figure which shows the effect | action of the electric field with respect to a metal pigment. FIG. 2 is a block diagram illustrating a configuration of a printer. 5A and 5B are schematic views showing the periphery of the print area of the first embodiment. It is the schematic which shows the electrode arrangement | positioning of 1st Embodiment. 7A and 7B are schematic views showing the action of the electric field of the first embodiment. It is a figure which shows the waveform of the applied voltage of 1st Embodiment. 9A and 9B are schematic views showing the action of the electric field of the second embodiment. It is a figure which shows the waveform of the applied voltage of 2nd Embodiment. It is the schematic which shows the electrode arrangement | positioning of 3rd Embodiment. It is the schematic which shows the effect | action of the electric field of 3rd Embodiment.

  At least the following matters will become clear from the description of the present specification and the accompanying drawings.

A liquid that hardens when irradiated with light, forming a dot by spraying a liquid containing a metal pigment onto a medium, applying an electric field to the dot, and applying the electric field to the dot A liquid jet recording method having light irradiation is clarified.
According to such a liquid jet recording method, it is possible to perform recording having a good metallic luster.

In this liquid jet recording method, it is preferable that the direction of the electric field acting on the dots has a component parallel to the medium.
According to such a liquid jet recording method, the metallic pigments within the dots are aligned on a plane parallel to the medium, and the direction of reflected light tends to be constant, so that a better metallic luster can be obtained.

In this liquid jet recording method, an electric field parallel to the medium transport direction is formed using a plurality of electrodes perpendicular to the medium transport direction, and the voltage applied to the electrodes is switched between positive and negative. It is desirable to change the direction of the electric field.
According to such a liquid jet recording method, the direction of the electric field acting on the dots can be controlled by the positive / negative of the voltage applied to the electrodes regardless of the arrangement of the ink nozzles.

In this liquid jet recording method, it is preferable that the electrodes have an interval equal to the dot pitch in the medium transport direction, and the polarity of the applied voltage is switched according to the cycle of the liquid jet.
According to such a liquid jet recording method, the direction of the electric field acting on the dots can be controlled in units of one dot, and an electric field in a certain direction can always be applied even during dot transport.

In this liquid jet recording method, the electrodes are spaced by n times the dot pitch in the medium conveyance direction, and a pulse-shaped waveform voltage is applied to the electrodes at every ejection cycle of n dots. desirable.
According to such a liquid jet recording method, an electric field in the same direction can be applied to every n dots.

In such a liquid jet recording method, it is desirable to form an electric field in a direction perpendicular to the medium conveyance direction by using a plurality of electrodes that are parallel to the medium conveyance direction and do not overlap the dots.
According to such a liquid jet recording method, when the pitch of the jet nozzles in the medium width direction is determined, a constant electric field can be continuously applied to each dot in the paper width direction without changing the polarity of the electrodes. it can.

In this liquid jet recording method, it is desirable to change the intensity of the electric field by changing the magnitude of the voltage applied to the electrode.
According to such a liquid jet recording method, the texture of the metallic luster can be changed by changing the force acting on the metal pigment in the dots.

  Further, a liquid that is hardened when irradiated with light, and forms a dot by ejecting a liquid containing a metal pigment onto a medium; an electrode that applies an electric field to the dot; and the electric field acts A liquid jet recording apparatus including an irradiating unit that irradiates light to the dots thus formed is clarified.

<Recording method with metallic luster>
The concept of a recording method having a metallic luster using a photocurable ink, which is performed by an ink jet printer or the like, will be described.

The photocurable liquid ejected from the nozzle onto the medium forms dots by landing on the medium. This liquid contains fine metal foil pieces such as aluminum flakes as pigments. On the recording surface formed by ejecting the liquid, the metallic pigment can be expressed on the recording surface by reflecting light with the metal pigment.
In the comparative example, the metal pigment is scattered and distributed in irregular positions and directions within the dots formed on the medium as shown in FIG. When the dots are cured by irradiating light in this state, the metal pigment is also fixed in a scattered state within the dots.

However, since the metal pigment is distributed in an irregular direction within the dot, the reflected light is also reflected in an irregular direction, and the metal luster texture obtained from the comparative example is not sufficient. .
On the other hand, in the embodiment, an electric field is applied to the dots in order to solve the problem of metallic luster texture.
As shown in FIG. 2, when the positive electrode and the negative electrode are arranged at the lower part of the medium so as to sandwich the dot, the electric field formed from the positive electrode toward the negative electrode also acts on the metal pigment in the dot. In other words, electrostatic induction occurs (when a charged object is brought close to a conductor, different types of charges are collected near the charged body and the same type of charge is collected at the far part), and negative charges are generated on the positive electrode side of the metal pigment. However, positive charges are collected on the negative electrode side. As a result, a Coulomb force due to an electric field (particularly a component parallel to the medium) acts on the electric charge in the metal pigment. Then, as shown in FIG. 3, along the lines of electric force forming the electric field, the longitudinal direction of the metal pigment is oriented in parallel with the medium.

  As a result, the metal pigments scattered within the dots are aligned with the longitudinal direction oriented in the direction of the lines of electric force (Fig. 2). Since the metal pigments on the entire recording surface are aligned in a certain direction, the reflected light from the metal pigments also travels in a certain direction. Therefore, it is possible to express a good metallic luster.

=== First Embodiment ===
In the first embodiment, a line printer (printer 1) will be described as an example of a recording apparatus.

<Printer configuration>
FIG. 4 is a block diagram of the overall structure of the printer 1.
The printer 1 is a recording device that records (prints) characters and images on a medium such as paper, cloth, and film, and is communicably connected to a computer 110 that is an external device.

A printer driver is installed in the computer 110. The printer driver is a program for displaying a user interface on a display device (not shown) and converting image data output from an application program into print data. This printer driver is recorded on a recording medium (computer-readable recording medium) such as a flexible disk FD or a CD-ROM. Alternatively, the printer driver can be downloaded to the computer 110 via the Internet. In addition, this program is comprised from the code | cord | chord for implement | achieving various functions.
Then, the computer 110 outputs print data corresponding to the image to be printed to the printer 1 in order to cause the printer 1 to print an image.

  The “recording device” means a device that records characters and images on a medium, and corresponds to, for example, the printer 1.

  The printer 1 of the present embodiment prints an image on a medium by ejecting ultraviolet curable ink (hereinafter, UV ink) that is cured by irradiating ultraviolet rays (hereinafter, UV). The UV ink is an ink containing an ultraviolet curable resin, and is cured by undergoing a photopolymerization reaction in the ultraviolet curable resin when irradiated with UV. Note that the printer 1 of the present embodiment performs printing using UV inks (color inks) of four colors of KCMY and UV inks (metal color inks) containing metal foil pieces as pigments.

  The metal pigment contained in the metal color ink used in the present embodiment is preferably one that has a high electrical conductivity and can secure a high metallic luster so as to be affected by an electric field. An example is aluminum flakes made of an aluminum alloy.

  The printer 1 of this embodiment includes a transport unit 20, a head unit 30, an irradiation unit 40, an electrode unit 50, a detector group 60, and a controller 70. The controller 70 controls each unit based on print data received from the computer 110 that is an external device, and prints an image on a medium. The situation in the printer 1 is monitored by a detector group 60, and the detector group 60 outputs a detection result to the controller 70. The controller 70 controls each unit based on the detection result output from the detector group 60.

<Transport unit>
The transport unit 20 is for transporting a medium (for example, paper S) in a predetermined direction (hereinafter referred to as a transport direction). The transport unit 20 includes an upstream transport roller 23A, a downstream transport roller 23B, and a belt 24 (FIGS. 5A and 5B). When a transport motor (not shown) rotates, the upstream transport roller 23A and the downstream transport roller 23B rotate, and the belt 24 rotates. The medium fed by a feed roller (not shown) is conveyed to a printable area (area facing the head) by the belt 24. The paper S that has passed through the printable area is discharged to the outside by the belt 24. The paper S being conveyed is electrostatically attracted or vacuum attracted to the belt 24.

<Head unit>
The head unit 30 is for ejecting UV ink onto a medium. In the present embodiment, as the UV ink, a color ink for forming an image and a metal color ink containing a metal pigment are ejected.

  The head unit 30 discharges each ink to the medium being transported to form dots on the medium, and prints an image on the medium. The printer 1 of the present embodiment is a line printer, and each head of the head unit 30 can form dots for the medium width at a time. In FIG. 5A, in order from the upstream side in the transport direction, a black ink head K that ejects black UV ink, a cyan ink head C that ejects cyan UV ink, a magenta ink head M that ejects magenta UV ink, A yellow ink head Y that discharges yellow UV ink and a metal color ink head MTL that discharges transparent UV ink containing a metal pigment are provided. Hereinafter, a head that discharges color ink is referred to as a color ink head, and a head that discharges metal color ink is also referred to as a metal color ink head.

  In addition, by including a metal pigment in each color of KCMY, it is possible to provide only a color ink head without providing an independent metal color ink head (FIG. 5B).

<Irradiation unit>
The irradiation unit 40 irradiates UV toward the dots (ink dots) of the UV ink landed on the medium. The dots formed on the medium by each head of the head unit 30 are cured by receiving UV irradiation from the irradiation unit 40.
The irradiation unit 40 includes a provisional curing irradiation unit 41 and a main curing irradiation unit 42.

  The pre-curing irradiation unit 41 irradiates UV for pre-curing the dots formed on the medium. In addition, in this embodiment, temporary hardening is hardening performed in order to fix the metallic pigment in a dot in the aligned state, and to prevent a blur between dots.

  In the present embodiment, the provisional curing irradiation unit 41 includes a light emitting diode (LED) as a light source for UV irradiation. The LED can easily change the irradiation energy by controlling the magnitude of the input current.

  The provisional curing irradiation unit 41 is provided on the downstream side of the head unit 30 in the transport direction of the KCMY heads. This is to prevent the ink dots formed on the medium from bleeding.

  Moreover, it is provided also in the conveyance direction downstream side of the metal color head and the electrode unit 50 described later. This is because it is necessary to cure the dots after applying an electric field to the ink dots by the electrode unit 50 and aligning the metal pigments inside the metal color ink.

The length in the medium width direction of the pre-curing irradiation unit 41 is equal to or greater than the medium width.
The main curing irradiation unit 42 irradiates UV for main curing dots formed on the medium. In the present embodiment, the main curing is curing performed for completely solidifying the dots.
The main curing irradiation unit 42 includes a lamp (a metal halide lamp, a mercury lamp, or the like) as a light source for UV irradiation.
The main curing irradiation unit 42 is provided further downstream than the temporary curing irradiation unit 41 located on the most downstream side in the transport direction (FIGS. 5A and 5B). Then, the main curing irradiation unit 42 irradiates the dots temporarily cured by the preliminary curing irradiation unit 41 with UV, and completely solidifies all the dots formed on the medium.
Further, the length of the main curing irradiation unit 42 in the medium width direction is equal to or greater than the medium width.

<Electrode unit>
The electrode unit 50 applies an electric field to the dots of the metallic color ink formed on the medium. When an electric field is applied to the metallic pigment contained in the metallic color ink, the metallic pigment is aligned in the longitudinal direction in the direction of the electric force lines forming the electric field by the action of the Coulomb force.

  The electrode unit 50 is connected to a plurality of pairs of electrodes 51A and 51B installed perpendicular to the transport direction on a plane parallel to the medium, and the electrodes 51A and 51B so as to sandwich the medium in parallel with the medium transport direction. The conductive portions 52A and 52B are configured (FIG. 6).

  The electrodes 51A and 51B are alternately arranged at equal intervals, and the intervals are equal to the intervals in the transport direction of dots formed on the medium. For example, in the present embodiment, when dots are formed at an interval of 0.5 mm in the transport direction, the interval between the electrodes 51A and 51B is also 0.5 mm. The lengths of the electrodes 51A and 51B are each equal to or greater than the medium width.

When positive and negative voltages are respectively applied to the conductive portions 52A and 52B, a potential difference is generated between the electrodes 51A and 51B via the 52A and 52B, and an electric field is formed in a direction parallel to the transport direction of the medium. This makes it possible to apply an electric field to the entire medium.
A method for applying the voltage will be described later.

<Detector group>
The detector group 60 includes a rotary encoder (not shown), a paper detection sensor (not shown), and the like. The rotary encoder detects the rotation amount of the upstream side conveyance roller 23A and the downstream side conveyance roller 23B. The transport amount of the medium can be detected based on the detection result of the rotary encoder. The paper detection sensor detects the position of the leading edge of the medium being fed.

<Controller>
The controller 70 is a control unit (control unit) for performing printer control. The controller 70 includes an interface unit 71, a CPU 72, a memory 73, and a unit control circuit 74. The interface unit 71 transmits and receives data between the computer 110 which is an external device and the printer 1. The CPU 72 is an arithmetic processing unit for controlling the entire printer. The memory 73 is for securing an area for storing the program of the CPU 72 and a work area, and has a storage element such as a RAM / EEPROM.
The CPU 72 controls each unit via the unit control circuit 74 in accordance with a program stored in the memory 73.

<About printing operation>
When the printer 1 receives print data from the computer 110, the controller 70 first rotates a paper feed roller (not shown) by the transport unit 20 and sends a medium to be printed onto the belt 24. The medium is conveyed on the belt 24 without stopping at a constant speed, and passes through the head unit 30, the electrode unit 50, and the irradiation unit 40.

  For example, in the case of FIG. 5A, first, dots are formed on the medium by discharging color ink from the nozzles of the respective color ink heads of the head unit 30, and UV is irradiated from the irradiation unit 41 of the irradiation unit 40 to perform color Temporarily cure the ink dots. The temporary curing is performed in order to prevent bleeding between ink dots of different colors.

  Next, metal color ink dots are formed on the medium by discharging the metal color ink from the metal color head. Subsequently, after an electric field is applied to the formed dots by the electrode unit 50, UV is irradiated from the irradiation unit 41 of the irradiation unit 40 to temporarily cure the metal color ink dots. Thereby, the metallic pigments inside the dots are fixed in an aligned state. Then, UV is irradiated from the irradiation unit 42 to fully cure the entire dot.

  Thus, an image is printed on the medium. Finally, the controller 70 discharges the medium on which image printing has been completed.

  The basic operation is the same in the case of FIG. 5B. After forming dots of color ink containing a metal pigment, an electric field is applied by the electrode unit 50, and the dots are temporarily cured by irradiating UV from the irradiation unit 41. This is repeated for each color of KCMY, and finally UV is irradiated from the irradiation unit 42 to fully cure the entire dot.

<Change in electrode potential during transport>
The ink ejected from the head lands on the medium to form dots (ink dots). Ink is ejected from the head unit 30 intermittently at a predetermined frequency F (Hz). Further, the medium is transported from the transport upstream side to the downstream side by the transport unit 20 at a constant speed V (mm / s). Thereby, dots are formed at equal intervals in the carrying direction, and the dot interval in the carrying direction is V / F (mm). Therefore, in the present embodiment, the distance between the electrodes 51A and 51B is also V / F (mm). For example, in this embodiment, assuming that the ink ejection frequency is 4.8 kHz and the medium conveyance speed is 500 mm / sec, the dot interval in the conveyance direction and the interval between the electrodes 51A and 51B are both 0.104 mm (240 dpi). Equivalent).

  FIG. 7A is a schematic diagram showing a relationship between an electric field formed by the electrode unit 50 and a dot subjected to the action of the electric field at a certain arbitrary time point. At this time, a positive voltage is applied to the transported upstream electrode 51A of the hatched dot through the conductive portion 52A, and a negative voltage is applied to the transported downstream electrode 51B through the conductive portion 52B. Therefore, an electric field from the upstream side to the downstream side acts on the dots (FIG. 7A), and the metal pigments scattered in the dots are aligned in the same direction.

  Next, FIG. 7B shows a state where the dots are conveyed downstream by one dot (V / F mm) by the conveyance unit 20. In this case, a positive voltage is applied to the electrode 51B on the upstream side of the dot, and a negative voltage is applied to the electrode 51A on the downstream side of the dot. Therefore, an electric field from the upstream side to the downstream side acts on the dots.

  The direction of the electric field acting on the dots is the same in the case of FIGS. 7A and 7B, and by repeating this operation, the force acting on the metal pigment in the dots is always kept in the same direction throughout the medium transport process.

  In this way, by sequentially switching the polarity of the voltage applied to the electrode unit in accordance with the dot conveyance speed, it is possible to apply a constant continuous force to the dots even during medium conveyance. The timing of switching the applied voltage can be based on the frequency F at which the head unit ejects ink. In the present embodiment, the applied voltage is switched between positive and negative at the moment when the conveyed dot passes through the position of the electrode. An example of the waveform of the applied voltage is shown in FIG.

  The voltage applied to the electrode unit is determined from the back side of the medium in consideration of the distance between the electrodes 51A and 51B (V / F mm in this embodiment), the thickness of the medium, and the thickness of the transport belt 24. The value is determined such that a sufficient electric field can be applied to the dots. For example, in this embodiment, when the electrode interval is 0.1388 mm and the medium thickness is about 0.5 mm, an electric field can be applied to the dots by applying a voltage of about 2 kV. . Furthermore, the electric field strength can be changed by changing the magnitude of the applied voltage. Thereby, the force applied to the metal pigment also changes, and the stronger the electric field, the easier the metal pigment is aligned. Therefore, it is possible to change the texture of the metallic luster depending on the magnitude of the applied voltage.

  Note that the voltage applied to the electrode unit is not necessarily continuous, and the voltage may be applied periodically only for a certain period of time during the conveyance of the medium.

  The waveform of the voltage applied to the electrode unit 50 is controlled by the controller 70. In the present embodiment, the unit control circuit 74 of the controller 70 instructs each head of the head unit to eject ink, and instructs the magnitude and cycle of the voltage applied to the electrodes 51A and 51B in accordance with the ejection timing. .

=== Second Embodiment ===
The basic configuration of the second embodiment is the same as that of the first embodiment. However, the configuration of the electrode unit 50 is different between the first embodiment and the second embodiment.
FIG. 9A and FIG. 9B are schematic diagrams showing the relationship between the electric field formed by the electrode unit 50 and the dots that receive the action of the electric field in the second embodiment.
In the first embodiment, the distance between the electrodes 51A and 51B is equal to the dot pitch formed in the medium transport direction. In contrast, in the second embodiment, the distance between the electrodes 51A and 51B is equal to n times the dot pitch in the medium transport direction. Here, n is a natural number, and FIGS. 9A and 9B show the case where n = 3.

  For example, in Embodiment 2, when the ink ejection frequency is 14.4 kHz and the medium conveyance speed is 500 mm / sec, the dot interval in the conveyance direction is 0.0347 mm (equivalent to 720 dpi). In this case, if n = 3, the distance between the electrodes 51A and 51B can be 0.104 mm, which is three times the dot distance.

  As described above, in the second embodiment, even when the electrode interval is about the same as that in the first embodiment (about 0.104 mm), it is possible to record with a finer dot interval, and when printing with higher resolution is performed. Is suitable.

<Change in electrode potential during transport>
In the second embodiment, the waveform of the voltage applied to the electrode unit is pulsed as shown in FIG. This is because n dots are considered as one group, and an electric field is applied in the same direction in units of n dots.

  In FIG. 9A, for three hatched dots (hereinafter referred to as dot group), a positive voltage is applied to the upstream electrode 51A in the medium transport direction, and a negative voltage is applied to the downstream electrode 51B in the transport direction. Accordingly, an electric field from the upstream side to the downstream side in the transport direction acts on the dot group, and the metal pigments in the dots are aligned in the medium transport direction.

  The medium is transported downstream by the transport unit 20 at a constant speed. During this time, the voltage applied to the electrode units 51A and 51B is zero (FIG. 10). Therefore, an electric field is not formed while the dot group is being conveyed, and the metal pigment is not affected.

  In FIG. 9B, when the dot group is transported by 3 dots from the state of FIG. 9A, a positive voltage is applied to the electrode 51B on the upstream side in the transport direction of the dot group, and a negative voltage is applied to the electrode 51A on the downstream side in the transport direction. Applied (FIG. 10). As a result, the electric field from the upstream side to the downstream side in the transport direction acts on the dot group again.

  By repeating this operation, an electric field in a certain direction can be intermittently applied to the group of dots while the medium is transported. The timing of voltage application is based on the frequency F at which the head unit ejects ink. In this embodiment, the applied voltage is set to zero at the moment when the most downstream dot in the transport direction (the rightmost dot in the dot group of FIG. 9A) passes through any electrode in the dot group. Then, a voltage in which positive and negative are switched is applied at the moment when the most upstream dot in the transport direction (the leftmost dot in the dot group of FIG. 9A) passes through the same electrode.

=== Third Embodiment ===
In the third embodiment, the electrodes 51A and 51B are arranged in parallel to the medium transport direction. As a result, the electric field is formed perpendicular to the medium transport direction. The configuration of the electrode unit 50 and the basic configuration other than the voltage application method are the same as in the first embodiment.
In FIG. 11, the outline of arrangement | positioning of the electrode unit installed in 3rd Embodiment is shown.

<Electrode unit>
In the third embodiment, the electrode unit 50 is connected to a plurality of pairs of electrodes 51A and 52B installed in parallel to the transport direction on a plane parallel to the medium, and the electrodes 51A and 51B, and is perpendicular to the transport direction of the medium. It is comprised from the electroconductive part 52A and 52B to be installed (FIG. 11).

The electrodes 51A and 51B are alternately arranged at equal intervals. The interval may be equal to or greater than the interval in the medium width direction of dots formed on the medium, but more preferably equal to m times the dot interval. Here, m is a natural number.
However, the positions of the electrodes 51A and 51B should not be directly below the dots. This is because if the dot is not between the electrodes 51A and 51B, the electric field cannot be applied, and the metal pigment is not aligned, so the problem of the invention cannot be solved. That is, the electrodes 51A and 51B need to be arranged so as not to overlap with the positions where dots are formed.
When positive and negative voltages are respectively applied to the conductive portions 52A and 52B, a potential difference is generated between the electrodes 51A and 51B via the 52A and 52B, and an electric field is formed in a direction perpendicular to the medium transport direction.

<Electrode potential during transport>
In 3rd Embodiment, there is no operation | movement which switches the polarity of the voltage applied to an electrode in the middle like 1st Embodiment or 2nd Embodiment. This is because it is not necessary to change the direction of the electric field acting on the dots during the conveyance of the medium.

  In this embodiment, the ink dots are always formed between the electrodes 51A and 51B (not directly above the electrodes). And this electrode is installed in parallel with the conveyance direction of a medium. Thus, while the medium is being transported, the ink dots are always between the same electrodes as they were formed. Therefore, if the voltage applied to the electrodes does not change, an electric field in the same direction always acts on the ink dots throughout the transport process.

  For example, when the interval between the ink dots in the medium width direction is 0.0347 mm (equivalent to 720 dpi), the electrodes 51A and 51B are arranged so as to pass through the center position of the adjacent ink dots at an interval of 0.104 mm, which is three times that interval. (FIG. 12). A positive voltage is applied to the electrode 51A, and a negative voltage is applied to the electrode 51B.

In this case, an electric field from 51A-1 to 51B-1 is generated between the electrode 51A-1 and the electrode 51B-1 in FIG. 12 and perpendicular to the medium transport direction. The dots formed between the electrodes 51A-1 and 51B-1 are affected by this electric field, and continue to be affected by the same electric field throughout the transport process.
Similarly, the dots formed between the electrode 51A-2 and the electrode 51B-1 continue to be affected by the electric field from 51A-2 to 51B-1 through the transport process.

  Thus, in the third embodiment, voltage application switching control is unnecessary. Therefore, if the positions of the dots formed in the medium width direction are clear in advance, it is possible to easily obtain a metallic luster having a good texture simply by determining the arrangement of the electrodes first.

=== Other Embodiments ===
Although a printer or the like as one embodiment has been described, the above embodiment is for facilitating the understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About the recording device>
In the above-described embodiment, a printer has been described as an example of an apparatus that realizes a recording method having good metallic luster. However, the present invention is not limited to this. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional molding machine, liquid vaporizer, organic EL manufacturing apparatus (especially polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The same technique as that of the present embodiment may be applied to various liquid jet recording apparatuses to which an ink jet technique is applied such as an apparatus and a DNA chip manufacturing apparatus.

<About ink>
In the above-described embodiment, ink (UV ink) that is cured by being irradiated with ultraviolet rays (UV) is ejected from the nozzle. However, the liquid to be ejected is not limited to such an ink, and may be cured by being irradiated with electromagnetic waves other than UV (for example, infrared rays or visible rays). In this case, electromagnetic waves (infrared rays, visible rays, etc.) for curing the liquid may be irradiated from the temporary curing irradiation unit and the main curing irradiation unit.

<About color ink>
In the above-described embodiment, metal color ink dots are formed after color ink dots are formed (FIG. 5A), but the order of ink dot formation is not limited to this. For example, the color ink dots may be formed after the metal color ink dots are formed, or the color ink dots and the metal color ink dots may be formed simultaneously.
Further, the number of color inks, the order of arrangement of the color ink heads, and the like are not limited to those of the above-described embodiment.

<About metal pigments>
In the above-described embodiment, aluminum flakes have been described as an example of the metal pigment contained in the ink, but the present invention is not limited to this. For example, metal foil powders such as gold, silver, copper, and zinc, or glass flakes coated with metal may be used as long as they can reflect light and receive an electric field effect.

<About electrodes>
In the above-described embodiment, the electric field is generated using a plurality of pairs of electrodes. However, a plurality of electrodes are not necessarily required. For example, even when there is only one pair of electrodes, the same effect as that of the above-described embodiment can be expected by the electric field generated between the electrodes.

1 printer, 20 transport unit,
23A upstream transport roller, 23B downstream transport roller,
24 belts, 30 head units, 40 irradiation units,
41 provisional curing irradiation unit, 42 main curing irradiation unit,
50 electrode unit, 51A electrode, 51B electrode,
52A conductive portion, 52B conductive portion, 60 detector group,
70 controller, 71 interface section,
72 CPU, 73 memory, 74 unit control circuit,
110 computer

Claims (8)

A liquid that cures when irradiated with light, forming a dot by ejecting a liquid containing a metal pigment onto a medium;
Applying an electric field to the dots;
Irradiating light to the dots acted on by the electric field;
A liquid jet recording method comprising: The liquid jet recording method according to claim 1,
A liquid jet recording method in which an electric field acting on the dots has a component parallel to the medium. The liquid jet recording method according to claim 1, wherein:
Forming an electric field in a direction parallel to the medium transport direction using a plurality of electrodes perpendicular to the medium transport direction,
A liquid jet recording method in which the direction of the electric field is changed by switching between positive and negative voltages applied to the electrodes. The liquid jet recording method according to claim 3,
The electrode is at an interval equal to the dot pitch in the transport direction of the medium;
A liquid jet recording method for switching between positive and negative voltages applied in accordance with the liquid jet cycle. The liquid jet recording method according to claim 3,
The electrodes are spaced by n times the dot pitch in the medium transport direction;
A liquid jet recording method in which a voltage having a pulse waveform is applied to the electrode at every n dot ejection cycles. The liquid jet recording method according to claim 1, wherein:
A liquid jet recording method for forming an electric field in a direction perpendicular to a medium transport direction by using a plurality of electrodes that are parallel to the medium transport direction and do not overlap dots. The liquid jet recording method according to any one of claims 1 to 6,
A liquid jet recording method in which the intensity of the electric field is changed by changing the magnitude of a voltage applied to the electrode. A liquid that hardens when irradiated with light, and forms dots by ejecting a liquid containing a metal pigment onto a medium; and
An electrode for applying an electric field to the dots;
An irradiating unit for irradiating light to the dots acted on by the electric field;
A liquid jet recording apparatus comprising: