JP2007083566A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device applicable to an imaging method adopting a crosslinkable inkjet ink which is free from a feathering/bleeding phenomenon, even in case whatever kind of a recording medium is used, and has high adhesive properties to a base material, high print quality and versatile applicability to a recording medium. <P>SOLUTION: This imaging device comprises a recording head for discharging inkjet ink to the recording medium, an active energy radiation irradiation means which irradiates the discharged ink with active energy radiations and a drying means for drying the recording medium to which the ink is discharged, wherein the inkjet ink includes at least a coloring material, water, a polymer compound having a hydrophilic main chain, and a plurality of side chains which can crosslink each other by irradiating them with active energy radiations. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an ink jet recording method, and has good feathering and low ink absorbency when recording on plain paper, and beading and color bleeding on a medium having no ink absorbability. Further, the present invention relates to an image forming apparatus using an ink jet recording method having excellent scratch resistance, water resistance, gloss, and fading.

  The ink jet recording method is capable of recording high-definition images with a relatively simple apparatus, and has been rapidly developed in various fields. In addition, there are various uses, and a recording medium or ink suitable for each purpose is used.

  In particular, in recent years, the recording speed has been greatly improved, and printers having performance capable of withstanding light printing applications have been developed.

  However, in order to bring out the performance of the ink jet printer, an ink jet special paper provided with ink absorbability is required.

  When recording on coated paper or art paper that does not absorb much ink, or on plastic film that does not absorb ink at all, there are problems such as so-called bleeding, where different color ink liquids mix on the recording medium and cause color turbidity. In addition, there has been a problem in providing a variety of recording media to the ink jet recording method.

  In response to the above problems, a hot-melt ink jet recording method using a hot-melt ink composition made of a wax that is solid at room temperature has been proposed.

  Since this ink is solid at room temperature, the ink composition is solidified immediately after adhering, so that it has less color bleeding and provides good print quality regardless of paper quality.

  Since this ink is solid at room temperature, it is not soiled in the handling area, and since there is no substantial evaporation of the ink when melted, there is no nozzle clogging. Furthermore, an ink composition has been proposed that solidifies immediately after adhering and has little color bleeding and provides good print quality regardless of lipid (see Patent Documents 1 and 2).

  However, an image recorded by such a method has problems such as deterioration in quality due to the rise of dots and lack of scratching performance because the ink dots formed on the substrate are soft wax-like. It was.

  On the other hand, an inkjet recording ink that is cured by exposure to ultraviolet rays has been disclosed (see Patent Document 3). In addition, a so-called non-aqueous ink is proposed in which a pigment is essential, a triacrylate or higher polyacrylate is essential as a polymerizable material, and a main solvent is ketone or alcohol (patent). Reference 4).

  Further, an ink using an aqueous ultraviolet polymerization monomer has been proposed (see Patent Document 5).

  In these methods, since the ink itself is cured by a curing component, recording is possible even on a non-absorbent medium, but a large amount of a curing component other than a coloring material is contained and does not volatilize. The recording surface was swelled by ink dots, causing unnaturalness in image quality, particularly gloss.

The ink using the water-based polymerization monomer also contains a large amount of solvent components other than the color material, and the solvent component does not evaporate sufficiently only by actinic ray irradiation. In the recording medium, there is a problem that the recording surface is swelled by ink dots, so that there is a problem with scratching immediately after printing or a color tone is changed.
US Pat. No. 4,391,369 U.S. Pat. No. 4,484,948 U.S. Pat. No. 4,228,438 Japanese Patent Publication No. 5-64667 JP-A-7-224241

  Accordingly, an object of the present invention is to use a crosslinkable inkjet ink, prevent feathering and bleeding in any recording medium, have high adhesion to a substrate, high print quality, and versatility in recording media. An image forming method is provided.

  The above object of the present invention is achieved by the following means.

  1. Recording an inkjet ink containing at least a colorant, water, and a polymer compound having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays An image forming apparatus comprising: a recording head that ejects to a medium; an active energy ray irradiating unit that irradiates ink ejected with active energy rays; and a drying unit that dries the recording medium onto which the ink has been ejected.

  2. 2. The image forming apparatus according to claim 1, wherein the drying unit is a unit that blows temperature-controllable air or hot air onto the recording medium on which the ink is ejected.

  3. 2. The image forming apparatus according to claim 1, wherein the drying unit is a temperature-controllable hot plate that contacts a recording medium on which the ink is ejected.

  4). 2. The image forming apparatus according to claim 1, wherein the drying means is means for irradiating the recording medium with visible light or far infrared light.

  5. 5. The image forming apparatus as described in 4 above, wherein the means for irradiating the recording medium with visible light or far-infrared light as the drying means is the same as the active energy ray irradiating means.

  6). 2. The image forming apparatus according to claim 1, wherein the drying unit is composed of a roller or a pair of rollers capable of controlling temperature, which is in contact with the recording medium on which the ink is ejected.

  7). 2. The image forming apparatus according to claim 1, wherein the drying unit includes a temperature-controllable belt suspended on a roller and in contact with the recording medium on which the ink is ejected.

  8). 8. The image forming apparatus according to any one of 1 to 7, wherein a temperature of the recording medium by the drying unit is 40 ° C. to 100 ° C.

  9. 9. The image forming apparatus according to any one of 1 to 8, wherein the temperature of the recording medium by the drying unit is determined based on environmental temperature and humidity.

  According to the present invention, using a crosslinkable water-based inkjet ink, feathering and bleeding are prevented in any recording medium, the adhesiveness to the substrate is high, the printing quality is high, and the recording medium has a variety. An image forming method is obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  The present invention is for an inkjet that contains at least a colorant, water, and a polymer compound having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays. A recording head used in an ink jet recording method in which ink is ejected onto a recording medium, and then the active energy rays are applied to the ink ejected onto the recording medium to cure the ink and fix the ink on the recording medium; The present invention relates to an image forming apparatus having active energy ray irradiation means and drying means for drying ink ejected onto a recording medium.

  Ink-jet inks containing at least a colorant, water, and a polymer compound that has a plurality of side chains in a hydrophilic main chain and that can be cross-linked between side chains by irradiating active energy rays are ejected. After that, it is cured by being exposed to active energy rays, and is fixed on the recording medium. However, since the ink of the present invention is water-based and has a large amount of solvent (water) in the components, Although the ink crosslinks and cures upon irradiation and gels, the volatile solvent component does not volatilize immediately, and the ink immediately after curing or gelation retains the solvent component in the crosslinked gel.

  Therefore, in the case of an absorptive recording medium, the solvent component is immediately absorbed into the recording medium from the generated gel, which is also a balance with the absorption speed, and particularly in the case of a non-absorbing recording medium. The ink droplets on the recording medium maintain a predetermined strength by cross-linking, but the cross-linked gel is in a state in which the solvent component is retained, is soft, and the solvent evaporates and solidifies completely. Until fixing, there is a problem that the quality is deteriorated due to the rising of the dots and the rubbing performance is insufficient.

  Therefore, in the image forming apparatus of the present invention, the inkjet ink containing the polymer compound that can be cross-linked between the side chains is ejected from the recording head onto the recording medium, and the active energy ray irradiating means is used on the recording medium. After the ink droplets ejected on the recording medium are irradiated with active energy rays to cure the ink droplets, a drying means for further drying the crosslinked ink on the recording medium is provided. The irradiation with the active energy ray and the drying may be performed in parallel, that is, simultaneously.

  As for the drying temperature, the ink-jet ink according to the present invention is a water-based ink, and the temperature of the recording medium, and hence the temperature of the ink on the substrate, is preferably in the range of 40 ° C. to 100 ° C. Ink disturbance occurs due to volatilization (boiling) of (water), and if it is too low, drying takes time, and drying does not end in the apparatus.

  By combining such drying means, the ink is recorded on a recording medium and then gelled by irradiation with active energy rays, and then the recording medium is dried by the drying means to fix the ink. In addition, an ink-jet recorded product having high print quality and excellent in scratch resistance, water resistance, gloss, and fading is obtained with no feathering, beading, and bleeding on various recording media.

  The active energy ray as used in the present invention includes, for example, electron beam, ultraviolet ray, α ray, β ray, γ ray, X ray and the like. However, it is dangerous to human body, easy to handle, and industrially used. Electron beams and ultraviolet rays are widely used.

  When using an electron beam, the amount of the electron beam to be irradiated is preferably in the range of 0.1 to 30 Mrad. If it is less than 0.1 Mrad, a sufficient irradiation effect cannot be obtained, and if it exceeds 30 Mrad, the support or the like may be deteriorated.

  When ultraviolet rays are used, the light source is, for example, a low pressure, medium pressure, high pressure mercury lamp, metal halide lamp, xenon lamp having a light emission wavelength in the ultraviolet region, cold cathode tube, hot cathode tube having an operating pressure of several hundred Pa to 1 MPa. A conventionally well-known thing, such as LED, is used.

  As the irradiation condition of the active energy ray, it is preferable that the active energy ray is irradiated within 0.001 to 1.0 seconds after ink landing, and more preferably 0.001 to 0.5 second. In order to form a high-definition image, it is particularly important that the irradiation timing is as early as possible.

  As a method for irradiating active energy rays, a basic method is disclosed in Japanese Patent Application Laid-Open No. 60-132767. According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. In US Pat. No. 6,145,979, as an irradiation method, a method using an optical fiber or a method of applying a collimated light source to a mirror surface provided on the side of the head unit and irradiating the recording unit with UV light is disclosed. Yes.

Any of these irradiation methods can be used in the image forming method of the present invention.
Also preferred is a method in which the irradiation of active energy rays is divided into two stages, and the active energy rays are first irradiated by the above-described method within 0.001 to 2.0 seconds after ink landing, and further the active energy rays are irradiated. It is one of. By dividing the irradiation of the active energy ray into two stages, it is possible to further suppress the shrinkage of the recording material that occurs during ink curing.

(Inkjet recording method)
In the inkjet image recording method of the present invention, an inkjet ink comprising a polymer compound having a plurality of side chains in the hydrophilic main chain of the present invention and capable of being cross-linked between the side chains by irradiation with active energy rays. Alternatively, the inkjet ink set is ejected onto the recording medium, and the ink is cured by irradiating with active energy rays. Thereafter, the recording medium, that is, the ink on the recording medium is dried by a drying unit. .

(Image recording device member)
In the image forming apparatus used in the inkjet recording method of the present invention, as a member to be used, in order to prevent irradiation of the head surface due to irregular reflection of active energy rays, for example, ultraviolet rays, the transmittance and reflectance of the active energy rays are low. Things are preferred.

  The irradiation unit preferably has a shutter mounted. For example, when ultraviolet rays are used, the ratio of illuminance when opening and closing the shutter is preferably shutter open / shutter close = 10 or more, more preferably 100 or more. Preferably it is 10,000 or more.

  Next, an image forming apparatus used in the inkjet image recording method of the present invention will be described.

(Image recording device)
In the image recording apparatus used in the present invention, for example, the image forming unit is horizontally arranged, and the back surface of the recording medium in a predetermined range on the upper surface (the surface opposite to the image forming surface side) is driven by the suction device. Equipped with a platen that is supported by suction, a recording head that discharges ink from the nozzle outlet toward the recording medium, and an irradiation unit that includes these recording heads and active energy rays, and moves in the scanning direction during image formation A carriage, a drive circuit board that is mounted on the carriage and drives the carriage, a guide member (linear guide) that extends along the scanning direction and guides the movement of the carriage, and extends along the scanning direction In the longitudinal direction, the linear scale on which the optical pattern is disposed and the optical pattern mounted on the carriage and disposed on the linear scale are read. It is constituted by a linear encoder sensor that outputs a clock signal.

  The recording head is arranged so that the image forming surface of the recording medium conveyed on the platen and the nozzle surface on which the ejection port of the recording head is formed face each other during image recording. Each head is supplied with ink from a cartridge for recording ink through a tube for piping. A plurality of heads are provided as necessary. For example, in the case of using CMK shades of 6 colors and Y, and colorless ink, 8 recording heads are provided. Irradiation means provided with active energy rays are provided on both sides of the recording head.

  Hereinafter, an example of an embodiment of an image forming apparatus according to the inkjet recording method of the present invention will be described with reference to the drawings. However, the present invention is not limited to only the illustrated image forming apparatus.

(Embodiment)
FIGS. 1A and 1B are schematic diagrams illustrating an example of an image recording unit 1 that is a main part of an image recording apparatus applicable to the ink jet recording method of the present invention. FIG. 1A shows a top view, and FIG. 1B shows a perspective view.

  The image recording unit 1 includes a carriage 4, a recording head 2, an irradiation unit 3, a platen unit 7, and the like. In the image recording unit 1, a platen unit 7 is installed under the recording medium P. The platen unit 7 has a function of absorbing ultraviolet rays and absorbs extra ultraviolet rays that have passed through the recording material P. As a result, a high-definition image can be reproduced very stably.

  The recording medium P is guided by a guide member (not shown), and moves in the front direction (arrow) from the back in FIG. 1 by the operation of a conveying means (not shown). The recording head scanning means (not shown) scans the recording head 2 held by the carriage 4 by reciprocating the carriage 4 along the guide member (linear guide) 5 in the Y direction in FIG.

  The carriage 4 is installed on the upper side of the recording medium P, and accommodates a plurality of recording heads 3 to be described later according to the number of colors used for image printing on the recording medium P, with the discharge ports arranged on the lower side. The carriage 4 is installed in the image recording unit 1 so as to reciprocate in the Y direction in FIG. 1, and reciprocates in the Y direction in FIG. 1 by driving the head scanning means.

  In FIG. 1, the carriage 4 is illustrated as accommodating the recording head 2 of yellow (Y), magenta (M), and cyan (C). However, the carriage 4 is accommodated in the head carriage 4 at the time of implementation. The number of colors of the recording head 2 is determined as appropriate. For example, in addition to the three colors, black (K), two whites (W), light yellow (Ly), light magenta (Lm), light cyan (Lc), and light black (Lk) may be stored.

  The recording head 2 ejects ink jet ink supplied by an ink supply means (not shown) from a discharge port toward the recording medium P by operation of a plurality of discharge means (not shown) provided therein. To do. The ink jet ink ejected by the recording head 2 is composed of a polymer compound that can be cross-linked between side chains by irradiating active energy rays, and is cured by a polymerization reaction when irradiated with ultraviolet rays. .

  The recording head 2 is a fixed area (landing possible area) in the recording medium P during the scanning in which the recording head 2 moves from one end of the recording medium P to the other end of the recording medium P in the Y direction in FIG. Ink jet ink is ejected as ink droplets to land on the landable area.

  The above scanning is performed as many times as necessary, and after the ink jet ink is ejected toward one landable area, the recording medium P is appropriately moved from the back to the front in FIG. While performing scanning, the recording head 2 discharges ink for ink jet to the landing possible area adjacent to the back in FIG.

  An image is formed on the recording medium P by repeating the above operation and ejecting ink jet ink from the recording head 2 in conjunction with the head scanning means and the conveying means.

  The irradiation means 3 includes an ultraviolet lamp that emits ultraviolet light in a specific wavelength region with stable exposure energy and a filter that transmits ultraviolet light of a specific wavelength. Here, as the ultraviolet lamp, a mercury lamp, a metal halide lamp, an excimer laser, an ultraviolet laser, a cold cathode tube, a hot cathode tube, a black light, an LED (Light Emitting Diode) and the like can be applied. A cathode tube, a hot cathode tube, a mercury lamp or black light is preferred. In particular, a low-pressure mercury lamp, a hot cathode tube, a cold cathode tube, and a germicidal lamp that emit ultraviolet light having a wavelength of 254 nm are preferable because they can effectively prevent bleeding and control the dot diameter. By using black light as the radiation source of the irradiation means 3, the irradiation means 3 for curing the ink-jet ink can be produced at low cost.

  The irradiating means 3 has the same shape as the largest one that can be set in the image recording unit 1 among the landable areas where the recording head 2 ejects ink for ink jet by a single scan driven by the head scanning means, or can land. It has a shape larger than the region.

  The irradiation means 3 is fixed on both sides of the carriage 4 so as to be substantially parallel to the recording medium P.

  As described above, as a means for adjusting the illuminance of the ink discharge portion, not only the entire recording head 2 is shielded, but in addition, the ink discharge of the recording head 2 is determined from the distance h1 between the irradiation means 3 and the recording medium P. It is effective to increase the distance h2 between the recording section P and the recording medium P (h1 <h2), or to increase the distance d between the recording head 2 and the irradiation means 3 (d is increased). In addition, a bellows structure is preferable between the recording head 3 and the irradiation means 3.

  Here, the wavelength of the ultraviolet rays irradiated by the irradiation means 3 can be changed as appropriate by replacing the ultraviolet lamp or filter provided in the irradiation means 3.

(Recording head)
The recording head (ink jet print head) to be used may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, a thermal type) Examples thereof include an ink jet type, a bubble jet (registered trademark) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.), and a discharge type (for example, a spark jet type). The electro-mechanical conversion method is preferable, but any discharge method may be used.

  The image recording apparatus having the image recording unit as described above and having the drying means according to the present invention will be specifically described below with reference to the drawings.

  FIG. 2 is a schematic view of an image recording apparatus showing the first embodiment of the present invention. In the image recording unit 1, after an image is recorded on the recording medium P by scanning (main scanning) of the carriage 4 on which the recording head 2, the irradiation means 3, etc. are mounted, from the back of the recording medium P to the front direction (arrow) ), A drying fan that blows temperature-controllable air (wind) or hot air on the recording medium is provided as a drying means at a position downstream of the image recording unit 1. Yes (the fan itself is not shown here, but a hood 10 for housing it is shown). The hood 10 and the drying fan in the hood 10 are provided to face the recording medium surface.

  The drying fan may be combined with heat generating means (for example, a heating wire, a ceramic heater, etc.) to supply hot air. In addition, the temperature of the air is preferably temperature-controlled, so that the temperature of the recording medium is controlled as described above, and thus the temperature of the ink on the substrate is in the range of 40 ° C. to 100 ° C. Is preferred. The drying temperature varies depending on the drying means, the ink used, etc., but the temperature (drying temperature) of the recording medium is determined based on the environmental temperature and humidity in which the image recording apparatus is used so as to be optimal. It is preferable.

  In addition, as a means for blowing temperature-controllable air or warm air to the recording medium, for example, a blowing member provided with a large number of small-sized air outlets on the surface facing the recording medium surface is used instead of the drying fan. May be. The shape of the air outlet is not limited, and for example, a blower member having one or more slit-like air outlets in the main scanning direction may be used.

  In that case, although an air blower (for example, a fan) is arrange | positioned separately, a warm air can be blown from the blower outlet of an air blower member by the heating means with which the air blower member or between the air blower member and an air blower is equipped. It is preferable that the air outlet is arranged so that the air to be blown uniformly hits the recording medium. In this case, the air blowing surface is not necessarily a flat surface, and may have a roll shape or a cross section having a fan shape, for example, a quarter circle or the like.

  FIG. 3 is an example of an image recording apparatus provided with another drying means, and is a schematic view showing a second embodiment of the present invention.

  FIG. 3A is a side view of the image recording unit. After the recording medium moving from the right to the left of the paper is printed by the recording head 2, the hot plate 11 is used as a drying means from the back side of the recording medium. Warm and dry. There is no particular limitation on the hot plate, but the plate surface is made of a metal such as aluminum with good heat conductivity, such as aluminum, has a high surface processing accuracy, and uses a stainless steel heater that has excellent durability. Is preferred. Moreover, you may have a heating wire etc. inside.

  For example, a plate material made of aluminum, a heater sheath material made of stainless steel, and a plate surface using a heat insulating material such as silica having a smooth surface with little surface roughness and less friction with a recording material is preferable for conveyance. The temperature can be measured with a thermocouple or the like, and a monitor or one that can be controlled at a constant temperature is preferable.

  The specification may be such that the aluminum plate on the plate surface is curved to improve the contact state with the recording medium.

  FIG. 3B shows how the ink printed with the crosslinkable ink according to the present invention, cross-linked, cured by active energy rays, and gelled on the recording medium is dried and fixed by passing through the hot plate 11. ).

  Next, FIG. 4 is a schematic view showing a third embodiment of the image forming apparatus of the present invention.

  4A is a side view, and FIG. 4B is a view of the image recording unit 1 and the drying means of the apparatus viewed from the top. In the present embodiment, after the ink droplets are ejected from the recording head to the recording medium in the image recording unit, the recording medium that has been irradiated with the active energy rays moves on the platen 7 and serves as a drying means. Alternatively, it is irradiated with far infrared light and dried with radiant heat. Specific examples of the drying means for applying visible light or far-infrared light radiation include a lamp, and examples of the lamp include a halogen lamp, a far-infrared heater, and an incandescent bulb. When a halogen lamp or the like is used, it can also be used as an active energy ray (ultraviolet ray) irradiation means.

  In the figure, 12 is a lamp (for example, a halogen lamp), and 13 is a reflector.

  In FIG. 4, heat rays are irradiated from the upper surface side of the recording medium, but heating may be performed from the platen 7 side, that is, the lower surface. In this case, the platen is made of a material through which the radiation is transmitted, or a hole is formed in the platen so that the radiation can pass through and directly irradiate the back surface of the recording medium to the extent that the platen can be conveyed.

  FIG. 5 shows a fourth embodiment of the image forming apparatus of the present invention, in which printing is performed using a heating roller as a drying means, and drying after irradiation with active energy rays is performed. The heating roller may be on the back side or the printed side of the recording medium. In the figure, a heat-absorbing and heat-conducting material having a heating roller installed on the back side of the recording medium, here a heating means (for example, a halogen lamp, an incandescent lamp, or a heating element such as nichrome wire), For example, it is a hollow roller formed of a metal material such as aluminum or stainless steel, and is nipped between the pressure roller 14 disposed on the recording surface side of the recording medium (the linear pressure is usually 0 to 50 N / cm, Preferably, it is 0 to 10 N / cm.), And the recording medium is heated.

  The heating roller 16 is, for example, a columnar shape having an outer diameter of 50 mm (preferably in a range of 25 to 60 mm), and a heat conductive material, for example, an aluminum core (cylindrical pipe having a thickness of about 1.5 to 3 mm). On top of this, PFA (fluororesin) is coated as a surface layer with a thickness of 30 μm through an adhesive layer.

  The pressure roller has, for example, an outer diameter of 50 mm, a silicon rubber (40 ° on a rubber hardness Asker-C scale) on an aluminum core, and a fluororesin tube on the silicon rubber (thickness 30 μm (50 to 50 μm)). 80 μm)). Both are formed as soft soft rollers.

  If the hardness is too high, deformation or the like may occur due to rubbing of an image that is not sufficiently fixed on the recording surface, but it is preferable because pressurization can be performed at the same time and gloss is improved.

  Further, without providing the pressure roller, the conveyance direction of the recording medium may be bent along the heating roller and conveyed and heated. In this case, when the gelation of the ink after irradiation with active energy rays is insufficient, the printing surface does not contact the roller, which is preferable.

  Further, the heating roller and the counter roller may be heated by arranging a plurality of heating rollers in the conveying direction as a roller row instead of one or a pair. FIG. 6 is a side view of an image forming apparatus having a plurality of heating rollers. In FIG. 6, the heating roller 16, the heating means 15, the pressure roller 14 and the like are the same as those in FIG.

  Next, a fifth embodiment of the image forming apparatus of the present invention will be described with reference to FIG.

FIG. 7 is an example of an image forming apparatus using a heating belt as a drying unit.
The image recording unit 1 is the same, but the recording medium moved along the conveyance guide 7 after printing and curing is dried with a heating belt.

  Although the heating belt may be arranged on either the upper or lower side, in FIG. 7, it is heated and dried by the heating belt 17 installed on the lower surface side of the recording medium. In FIG. 7, the belt is heated by the heating roller 16. The heating means used for heating the heating roller is the same as in the fourth embodiment.

  The heating belt is supported by the heating roller 16 and the other roller 18 and is in close contact with the recording medium. Similarly to the pressure roller, the one roller 18 is made of, for example, a similar material in which a silicon rubber (elastic layer) is lined on an aluminum core and a surface layer is coated with a fluororesin. Further, the supporting roller 18 has a heating means, which may be used as a heating roller.

  In order to achieve close contact between the heating belt 17 and the recording medium P, a pressure roller 14 is installed opposite to the heating roller 16, and the recording medium is nipped and heated during this time. The nip pressure and the like are the same as in the fourth embodiment. The inner diameter of the heating roller is preferably about 50 to 80 mm.

  The pressure roller is the same as the pressure roller in the fourth embodiment.

  As the heating belt 17 used in the fifth embodiment of the present invention, for example, as a base, a metal belt such as a nickel electroformed belt having a thickness of about 30 to 70 μm, a polyimide having a thickness of about 50 to 90 μm, A heat-resistant resin belt made of polyamide or the like coated on the outside (outer peripheral surface) with an insulating silicon rubber having a thickness of about 100 to 250 μm, and a fluorine layer having a thickness of about 20 to 50 μm on the surface as a release layer What gave resin (PFA) coating processing is used.

  Further, the heating means is not a heating means such as a halogen lamp arranged in the heating roller, but, for example, a polyimide resin and a stainless steel foil heater element are integrally molded, and the thickness is about 0.1 to 1.0 mm. A flexible planar heating element which is a thin layer member may be used.

  Furthermore, another embodiment of an image forming apparatus having a heating belt will be shown. As shown in FIG. 8, as a member for heating the heating belt, a hot plate 11 may be disposed in close contact with the back surface of the heating belt (the side opposite to the recording medium).

  In addition, the heating belt may be provided not only on one side but also on the other side, and dried with heating belts located on both sides.

  Moreover, you may use one heating belt as a pressure belt except a heat generating body.

  These heating means are preferably controlled so that the temperature of the recording medium is maintained at a predetermined temperature between 40 ° C. and 100 ° C., and optimal drying conditions can be set according to the ink formulation. Can be done.

  While the embodiments 1 to 5 of the present invention have been described above, the crosslinkable ink that can be used in the present invention will be described below.

  The ink-jet ink used in the present invention has at least a colorant, water, and a polymer having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays. An ink containing a compound. Hereinafter, the components will be described.

  Hereinafter, each component and configuration of the ink according to the present invention will be described in detail.

<Active energy ray crosslinkable polymer compound>
The polymer compound having a plurality of side chains in the hydrophilic main chain according to the present invention and capable of crosslinking between the side chains by irradiating with active energy rays is a saponified product of polyvinyl acetate, polyvinyl acetal, polyethylene Oxide, polyalkylene oxide, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl cellulose, or a derivative of the hydrophilic resin, and at least one hydrophilic selected from the group consisting of these copolymers In the resin, a modified group such as a photodimerization type, a photodecomposition type, a photopolymerization type, a photomodification type, or a photodepolymerization type is introduced into the side chain. Photopolymerizable crosslinkable groups are desirable from the viewpoints of sensitivity and performance of the generated image.

  Further, from the viewpoint of reactivity with the color material to be combined, the side chain is preferably nonionic, anionic, or amphoteric (betaine compound). In particular, when the color material is combined with an anionic dye or an anionic pigment, The chain is preferably nonionic or anionic, particularly preferably nonionic.

In the hydrophilic main chain, a saponified product of polyvinyl acetate is preferable from the viewpoint of ease of introduction of side chains and handling, and the degree of polymerization is preferably 200 or more and 2000 or less, and more preferably 200 or more and 500 or less.
If the degree of polymerization is less than 200, the viscosity increase during the crosslinking reaction is insufficient, and color bleed and beading described later may not be sufficiently prevented. On the other hand, if the degree of polymerization exceeds 2000, the viscosity when added to the ink is increased, which may impair the emission stability.

  The modification rate of the side chain with respect to the main chain is preferably 0.3 mol% or more and 4 mol% or less, and more preferably 0.8 mol% or more and 4 mol% or less from the viewpoint of reactivity. If it is less than 0.3 mol%, the crosslinkability is insufficient and the effect of the present invention is reduced. If it is more than 4 mol%, the crosslink density is increased and the film is hard and brittle, and the strength of the film is lowered.

  As the photodimerization-type modifying group, those in which a diazo group, a cinnamoyl group, a stilbazolium group, a styrylquinolium group or the like is introduced are preferable. (Composition).

  The photosensitive resin described in JP-A-60-129742 is a compound represented by the following general formula (1) in which a stilbazolium group is introduced into a polyvinyl alcohol structure.

In the formula, R ₁ represents an alkyl group having 1 to 4 carbon atoms, and A ⁻ represents a counter anion.

  The photosensitive resin described in JP-A-56-67309 includes a 2-azido-5-nitrophenylcarbonyloxyethylene structure represented by the following general formula (2) in the polyvinyl alcohol structure, or the following general formula. This is a resin composition represented by (3) and having a 4-azido-3-nitrophenylcarbonyloxyethylene structure.

  Further, a modifying group represented by the following general formula (4) is also preferably used.

  In the formula, R represents an alkylene group or an aromatic ring. A benzene ring is preferred.

  As the photopolymerization type modifying group, for example, a resin represented by the following general formula (5) shown in JP-A Nos. 2000-181062 and 2004-189841 is preferable from the viewpoint of reactivity.

In the formula, R ₂ represents a methyl group or a hydrogen atom, n represents 1 or 2, X represents — (CH ₂ ) _m —COO— or —O—, and Y represents an aromatic ring or a single bond. And m represents an integer from 0 to 6.

  Moreover, it is also preferable to use the photopolymerization type | mold modified group represented by following General formula (6) described in Unexamined-Japanese-Patent No. 2004-161942 for a conventionally well-known water-soluble resin.

In the formula, R ₃ represents a methyl group or a hydrogen atom, and R ₄ represents a linear or branched alkylene group having 2 to 10 carbon atoms.

  Such an active energy ray-crosslinking resin is preferably contained in an amount of 0.8% by mass to 5.0% by mass with respect to the total mass of the ink. The presence of 0.8% by mass or more improves cross-linking efficiency, and beading and color bleeding are more preferable due to a rapid increase in ink viscosity after cross-linking. In the case of 5.0% by mass or less, it is difficult to adversely affect the physical properties of the ink and the state in the ink head, which is preferable from the viewpoints of light emission properties and ink storage stability.

  In the active energy ray cross-linking resin of the present invention, the main chain having a certain degree of polymerization is cross-linked through a cross-linking bond between side chains, and thus polymerizes through a general chain reaction. The effect of increasing the molecular weight per photon is significantly larger than that of an active energy ray curable resin. On the other hand, in the conventionally known active energy ray curable resins, the number of crosslinking points cannot be controlled, so the physical properties of the cured film cannot be controlled, and the film tends to be hard and brittle.

  In the resin used in the present invention, the number of crosslinking points can be completely controlled by the length of the hydrophilic main chain and the amount of side chains introduced, and the physical properties of the ink film can be controlled according to the purpose.

  Furthermore, almost all of the conventionally known active energy ray-curable inks other than the colorant are curable, so that the dots after curing are raised and inferior in image quality typified by gloss, are used in the present invention. The resin requires only a small amount, and since there are many dry components, the image quality after drying is improved and the fixing property is also good.

(Photopolymerization initiator, sensitizer)
In the present invention, it is preferable to add a photopolymerization initiator or a sensitizer. These compounds may be dissolved or dispersed in a solvent, or may be chemically bonded to the photosensitive resin.

  There is no restriction | limiting in particular about the photoinitiator and photosensitizer which are applied, A conventionally well-known thing can be used.

  Although there is no restriction | limiting in particular about the photoinitiator and photosensitizer which are applied, A water-soluble thing is preferable from a viewpoint of mixability and reaction efficiency. In particular, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (HMPK), thioxanthone ammonium salt (QTX), and benzophenone ammonium salt (ABQ) are preferable from the viewpoint of miscibility with an aqueous solvent.

  Furthermore, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone (n = 1, HMPK) represented by the following general formula (7) from the viewpoint of compatibility with the resin, The ethylene oxide adduct (n = 2 to 5) is more preferable.

  In the formula, n represents an integer of 1 to 5.

  Other examples include benzophenones such as benzophenone, hydroxybenzophenone, bis-N, N-dimethylaminobenzophenone, bis-N, N-diethylaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone. Thioxanthones such as thioxatone, 2,4-diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone, and isopropoxychlorothioxanthone. Anthraquinones such as ethyl anthraquinone, benzanthraquinone, aminoanthraquinone and chloroanthraquinone. Acetophenones. Benzoin ethers such as benzoin methyl ether. 2,4,6-trihalomethyltriazines, 1-hydroxycyclohexyl phenyl ketone, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di ( m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-phenylimidazole dimer, 2- (P-methoxyphenyl) -4,5-diphenylimidazole dimer, 2, -di (p-methoxyphenyl) -5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5 -2,4,5-triarylimidazole dimer of diphenylimidazole dimer, benzyldimethyl ketal, 2-benzyl-2-dimethyl Amino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-phenyl -Propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, phenanthrenequinone, 9,10-phenanthrenequinone, Benzoins such as methylbenzoin and ethylbenzoin, 9-phenylacridine, acridine derivatives such as 1,7-bis (9,9'-acridinyl) heptane, bisacylphosphine oxide, and mixtures thereof are preferably used. May be used alone or in combination.

  In addition to these photopolymerization initiators, accelerators and the like can also be added. Examples of these include ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, ethanolamine, diethanolamine, triethanolamine and the like.

  Even if these photoinitiators are grafted to the side chain with respect to the hydrophilic main chain.

(Active energy rays, irradiation method)
The active energy ray as used in the present invention includes, for example, electron beam, ultraviolet ray, α ray, β ray, γ ray, X ray and the like. However, it is dangerous to human body, easy to handle, and industrially used. Electron beams and ultraviolet rays are widely used.

  When using an electron beam, the amount of the electron beam to be irradiated is preferably in the range of 0.1 to 30 Mrad. If it is less than 0.1 Mrad, a sufficient irradiation effect cannot be obtained, and if it exceeds 30 Mrad, the support or the like may be deteriorated.

  When using ultraviolet rays, the light source is a low pressure, medium pressure, high pressure mercury lamp, metal halide lamp, xenon lamp having a light emission wavelength in the ultraviolet region, cold cathode tube, hot cathode tube, for example, having an operating pressure of 0.1 kPa to 1 MPa. A conventionally well-known thing, such as LED, is used.

(Light irradiation conditions after ink landing)
As the irradiation condition of the active energy ray, it is preferable that the active energy ray is irradiated within 0.001 to 1.0 seconds after ink landing, and more preferably 0.001 to 0.5 seconds. In order to form a high-definition image, it is particularly important that the irradiation timing is as early as possible.

(Installation of lamp)
As a method for irradiating active energy rays, a basic method is disclosed in Japanese Patent Application Laid-Open No. 60-132767. According to this, the light source is provided on both sides of the head unit, and the head and the light source are scanned by the shuttle method. Irradiation is performed after a certain period of time after ink landing. Further, the curing is completed by another light source that is not driven. In US Pat. No. 6,145,979, as an irradiation method, a method using an optical fiber or a method of applying a collimated light source to a mirror surface provided on the side of the head unit and irradiating the recording unit with UV light is disclosed. Yes. Any of these irradiation methods can be used in the image forming method of the present invention.

  Also preferred is a method in which the irradiation of active energy rays is divided into two stages, the active energy rays are first irradiated by the above-described method within 0.001 to 2.0 seconds after ink landing, and further the active energy rays are irradiated. It is one of. By dividing the irradiation of the active energy ray into two stages, it is possible to further suppress the shrinkage of the recording material that occurs during ink curing.

[Colorant]
As the color material used in the ink jet ink of the present invention, it is preferable to use a dye or a pigment.

(dye)
There is no restriction | limiting in particular as dye which can be used by this invention, Water-soluble dyes, such as an acid dye, a direct dye, and a reactive dye, a disperse dye, etc. are mentioned.

  Specific examples of dyes applicable to the ink jet ink of the present invention are listed below, but the present invention is not limited to these exemplified dyes.

[Water-soluble dye]
Examples of water-soluble dyes that can be used in the present invention include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, and diphenylmethane dyes.

<C. I. Acid Yellow>
1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 42, 44, 49, 59, 61, 65, 67, 72, 73, 79, 99, 104, 110, 114, 116, 118, 121, 127, 129, 135, 137, 141, 143, 151, 155, 158, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 220, 230, 232, 235, 241, 242, 246,
<C. I. Acid Orange>
3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168,
<C. I. Acid Red>
88, 97, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289, 296, 299, 315, 318, 336, 337, 37, 359, 361, 362, 364, 366, 399, 407, 415,
<C. I. Acid Violet>
17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126,
<C. I. Acid Blue>
1, 7, 9, 15, 23, 25, 40, 62, 72, 74, 80, 83, 90, 92, 103, 104, 112, 113, 114, 120, 127, 128, 129, 138, 140, 142, 156, 158, 171, 182, 185, 193, 199, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 239, 249, 258, 260, 264, 278, 279, 280, 284, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350,
<C. I. Acid Green>
9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109,
<C. I. Acid Brown>
2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413,
<C. I. Acid Black>
1, 2, 3, 24, 26, 31, 50, 52, 58, 60, 63, 107, 109, 112, 119, 132, 140, 155, 172, 187, 188, 194, 207, 222,
<C. I. Direct yellow>
8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 79, 86, 87, 98, 105, 106, 130, 132, 137, 142, 147, 153,
<C. I. Direct orange>
6, 26, 27, 34, 39, 40, 46, 102, 105, 107, 118,
<C. I. Direct Red>
2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 254,
<C. I. Direct Violet>
9, 35, 51, 66, 94, 95,
<C. I. Direct Blue>
1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 201, 202, 203, 218, 225, 229, 237, 244, 248, 251, 270, 273, 274, 290, 291,
<C. I. Direct Green>
26, 28, 59, 80, 85,
<C. I. Direct Brown>
44, 106, 115, 195, 209, 210, 222, 223,
<C. I. Direct Black>
17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169,
<C. I. Basic Yellow>
1, 2, 11, 13, 15, 19, 21, 28, 29, 32, 36, 40, 41, 45, 51, 63, 67, 70, 73, 91,
<C. I. Basic Orange>
2, 21, 22,
<C. I. Basic Red>
1, 2, 12, 13, 14, 15, 18, 23, 24, 27, 29, 35, 36, 39, 46, 51, 52, 69, 70, 73, 82, 109,
<C. I. Basic Violet>
1, 3, 7, 10, 11, 15, 16, 21, 27, 39,
<C. I. Basic Blue>
1, 3, 7, 9, 21, 22, 26, 41, 45, 47, 52, 54, 65, 69, 75, 77, 92, 100, 105, 117, 124, 129, 147, 151,
<C. I. Basic Green>
1, 4,
<C. I. Basic Brown>
1,
<C. I. Reactive Yellow>
2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102, 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160, 161, 165, 167, 168, 175, 176,
<C. I. Reactive Orange>
1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74, 82, 84, 86, 87, 91, 92, 93, 95, 107,
<C. I. Reactive Red>
2, 3, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78, 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190, 193, 194, 195, 198, 218, 220, 222, 223, 228, 235,
<C. I. Reactive Violet>
1, 2, 4, 5, 6, 22, 23, 33, 36, 38,
<C. I. Reactive Blue>
2, 3, 4, 5, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79, 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 161, 162, 163, 168, 171, 176, 182, 184, 191, 194, 195, 198, 203, 204, 207, 209, 211, 214, 220, 221, 222, 231, 235, 236,
<C. I. Reactive Green>
8, 12, 15, 19, 21,
<C. I. Reactive Brown>
2, 7, 9, 10, 11, 17, 18, 19, 21, 23, 31, 37, 43, 46,
<C. I. Reactive Black>
5, 8, 13, 14, 31, 34, 39,
<C. I. Food Black>
1, 2,
Etc.

  Furthermore, examples of the dye include a compound represented by the following general formula (8) or a compound represented by the general formula (9).

In the general formula (8), R ₁ represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom or a phenylcarbonyl group. R ₂ may be different and represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom. R ₃ represents a hydrogen atom or a substitutable substituent, and is preferably a hydrogen atom or an alkyl group. R ₄ represents a hydrogen atom or a substitutable substituent, preferably a hydrogen atom or an aryloxy group. R ₅ may be different and represents a hydrogen atom or a substitutable substituent, and is preferably a sulfonic acid group. n represents an integer of 1 to 4, and m represents an integer of 1 to 5.

In the general formula (9), X represents a phenyl group or a naphthyl group, may be substituted with a substitutable substituent, and is preferably substituted with a sulfonic acid group or a carboxyl group. Y represents hydrogen ion, sodium ion, potassium ion, lithium ion, ammonium ion or alkylammonium ion. R ₆ may be different and represents a hydrogen atom or a substituent that can be substituted on the naphthalene ring. q represents 1 or 2. p represents an integer of 1 to 4. However, q + p = 5. Z represents a substitutable substituent, and represents a carbonyl group, a sulfonyl group or a group represented by the following general formula (10), and particularly preferably a group represented by the following general formula (10).

In the general formula (10), W ₁ and W ₂ each independently represent a halogen atom, amino group, hydroxyl group, alkylamino group or arylamino group, preferably a halogen atom, hydroxyl group or alkylamino group.

[Disperse dye]
As the disperse dye, various disperse dyes such as azo disperse dyes, quinone disperse dyes, anthraquinone disperse dyes, quinophthalone disperse dyes can be used, and specific compounds thereof are listed below.

<C. I. Disperse Yellow>
3, 4, 5, 7, 9, 13, 23, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 64, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 108, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 160, 162, 163, 164, 165, 179, 180, 182, 183, 184, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, 227, 231, 232,
<C. I. Disperse Orange>
1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 47, 48, 49, 50, 53, 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142,
<C. I. Disperse Red>
1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 23 , 240,257,258,277,278,279,281,288,298,302,303,310,311,312,320,324,328,
<C. I. Disperse Violet>
1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77,
<C. I. Disperse Green>
9,
<C. I. Disperse Brown>
1, 2, 4, 9, 13, 19,
<C. I. Disperse Blue>
3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 3 0,333,
<C. I. Disperse Black>
1, 3, 10, 24
Etc.

<Pigment>
As the pigment that can be used in the ink according to the present invention, conventionally known organic and inorganic pigments can be used, and are anionic pigments. For example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc. Examples include cyclic pigments, dye lakes such as acid dye lakes, organic pigments such as nitro pigments, nitroso pigments, aniline black, and daylight fluorescent pigments, and inorganic pigments such as carbon black.

  Specific organic pigments are exemplified below.

  Examples of pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the orange or yellow pigment include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. And CI Pigment Yellow 138.

  Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  As a method for dispersing the pigment, for example, various dispersing machines such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used. It is also preferable to use a centrifugal separator or a filter for the purpose of removing the coarse particles of the pigment dispersion.

  In the ink according to the present invention, a self-dispersed pigment in which polar groups such as sulfonic acid and carboxylic acid are pendant on the pigment surface, or a pigment dispersed using a polymer dispersant is preferable.

  The polymer dispersant according to the present invention is not particularly limited, and a water-soluble resin or a water-insoluble resin is used. Examples of these polymers include styrene, styrene derivatives, vinyl naphthalene derivatives, acrylic acid, acrylic acid derivatives, methacrylic acid, methacrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, fumaric acid. Examples thereof include a polymer composed of a single monomer selected from acid derivatives, a copolymer composed of two or more monomers, and salts thereof. Water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulose derivatives, gelatin, and polyethylene glycol can also be used.

  The content of these water-soluble resins with respect to the total amount of ink is preferably 0.1 to 10% by mass, and more preferably 0.3 to 5% by mass. These water-soluble resins can be used in combination of two or more.

  The average particle size of the pigment dispersion used in the inkjet ink according to the present invention is preferably 500 nm or less, more preferably 200 nm or less, preferably 10 nm or more and 200 nm or less, and more preferably 10 nm or more and 150 nm or less. If the average particle size of the pigment dispersion exceeds 500 nm, the dispersion becomes unstable. In addition, even when the average particle size of the pigment dispersion is less than 10 nm, the stability of the pigment dispersion tends to deteriorate, and the storage stability of the ink tends to deteriorate.

  The particle size of the pigment dispersion can be determined by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. It is also possible to obtain a particle image with a transmission electron microscope on at least 100 particles and perform statistical processing on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). Is possible.

  Various methods such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used as a pigment dispersion method.

<Water-soluble solvent>
As the solvent relating to the ink of the present invention, an aqueous liquid medium is preferably used, and as the aqueous liquid medium, a mixed solvent such as water and a water-soluble organic solvent is more preferably used. Examples of water-soluble organic solvents that are preferably used include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, Triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), polyhydric alcohol ethers (eg, ethylene glycol monomethyl ether, ethylene Glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Nomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol Monophenyl ether, propylene glycol monophenyl ether), amines (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetra) , Tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2 -Pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone), sulfoxides (for example, dimethyl sulfoxide) and the like.

<Surfactant>
Surfactants preferably used in the ink according to the present invention include alkyl sulfates, alkyl ester sulfates, dialkyl sulfosuccinates, alkyl naphthalene sulfonates, alkyl phosphates, polyoxyalkylene alkyl ether phosphates, Anionic surfactants such as fatty acid salts, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyalkylene alkyl phenyl ethers, acetylene glycols, polyoxyethylene-polyoxypropylene block copolymers, glycerin esters, Activators such as sorbitan esters, polyoxyethylene fatty acid amides, amine oxides, and cationic surfactants such as alkylamine salts and quaternary ammonium salts.

  These surfactants can also be used as pigment dispersants, and in particular, anionic and nonionic surfactants can be preferably used.

<Various additives>
The ink according to the present invention can contain other conventionally known additives. For example, optical brighteners, antifoaming agents, lubricants, preservatives, thickeners, antistatic agents, matting agents, water-soluble polyvalent metal salts, acid bases, pH adjusting agents such as buffer solutions, antioxidants, conductivity They are regulators, surface tension modifiers, rust inhibitors, inorganic pigments, and the like.

<Recording sheet>
The paper, coated paper, there is a non-coated paper, as the coated paper, the coating amount per 1m ² is one side 20g before and after of art paper, 1m ² per coated amount on one side 10g before and after the coated paper Examples include a light-weight coated paper having a coating amount per 1 m ^{2 of} about 5 g on one side, a finely coated paper, a mat-like finished mat-coated paper, a dull-like finished dull-coated paper, and a newsprint. Non-coated paper includes printing paper A using 100% chemical pulp, printing paper B using 70% or more chemical pulp, printing paper C using 40% or more and less than 70% chemical pulp, and printing using less than 40% chemical pulp. Examples thereof include paper D, gravure paper containing mechanical pulp and subjected to calendar treatment. Further details are described in detail in the “Latest Paper Processing Handbook” edited by the Paper Processing Handbook Editorial Committee, published by Tech Times, “Printing Engineering Handbook” edited by the Japan Printing Society.

  The plain paper is 80 to 200 μm uncoated paper belonging to a part of uncoated paper, special printing paper and information paper. The plain paper used in the present invention includes, for example, high-grade printing paper, intermediate-grade printing paper, low-grade printing paper, thin-like printing paper, fine-coating printing paper, special printing paper such as fine-quality printing paper, foam paper, PPC paper, and others There are information sheets and the like. Specifically, there are the following sheets and various modified / processed sheets using these sheets, but the present invention is not particularly limited thereto. High quality paper and colored high quality paper, recycled paper, copy paper / colored paper, OCR paper, carbonless paper / colored paper, synthetic paper such as YUPO 60, 80, 110 microns, YUPO COAT 70, 90 microns, etc. Coated paper 90kg, Foam mat paper 70, 90, 110kg, Foamed PET 38 microns, Mitsuori-kun (above, Kobayashi recording paper), OK fine paper, New OK fine paper, Sunflower, Phoenix, OK Royal White, Export fine paper ( NPP, NCP, NWP, Royal White) OK Book Paper, OK Cream Book Paper, Cream Premium Paper, OK Map Paper, OK Ishikari, Cucumber, OK Foam, OKH, NIP-N (above, Shin Oji Paper), Gold Wang, Toko, export quality paper, special demand quality paper, book paper, book paper L, light cream book paper, elementary textbook Paper, continuous slip paper, high quality NIP paper, silver ring, gold yang, gold yang (W), bridge, capital, silver ring book, harp, harp cream, SK color, securities paper, opera cream, opera, KYP medical record, silvia HN, Excellent Foam, NPI Foam DX (Nippon Paper), Pearl, Kinryo, Uscream fine paper, Special Book Paper, Super Book Paper, Book Paper, Diamond Foam, Inkjet Foam (Mitsubishi Paper), Carpet V, carpet SW, white elephant, luxury publication paper, cream carpet, cream white elephant, securities / voucher paper, book paper, map paper, copy paper, HNF (above, Hokuetsu), phone book cover, Book paper, cream shirairai, cream shirairaifu, cream shirairaifu, DSK (above, Daishowa Paper), Sendai MP fine paper, Jiang, Thunderbird quality, hanging paper, colored paper base, dictionary paper, cream book, white book, cream quality paper, map paper, continuous slip paper (above, Chuetsu Pulp), OP gold cherry (Chuetsu), gold sand, reference book paper, Replacement certificate paper (white), form printing paper, KRF, white foam, color foam, (K) NIP, fine PPC, Kishu inkjet paper (above, made by Kishu Paper), Taiou, Bright Foam, Kant, Kant White, Dante , CM paper, Dante comic, Heine, paperback book paper, Heine S, New AD paper, Utrilo Excel, Excel Super A, Kant Excel, Excel Super B, Dante Excel, Heine Excel, Excel Super C, Excel Super D, AD Excel, Excel Super E, New Bright Foam, New Bright NI P (above, made by Daio Paper), Sun Ring, Moon Ring, Cloud Pass, Galaxy, Baiyun, Wyeth, Moon Ring Ace, Baiyun Ace, Cloud Pass Ace (above, Nippon Paper Industries), Taiou, Bright Foam, Bright Nip (Nagoya Pulp), Peony A, Golden Pigeon, Special Peony, White Peony A, White Peony C, Silver Pigeon, Super White Peony A, Light Cream White Peony, Special Medium Quality Paper, White Pigeon, Super Medium Quality Paper, Blue Pigeon, Red Pigeon, Gold Pigeon M Snow Vision, Snow Vision, Gold Pigeon Snow Vision, White Pigeon M, Super DX, Hamanasu O, Red Pigeon M, HK Super Printing Paper (Made by Honshu Paper), Stalinden (A・ AW), Star Elm, Star Maple, Star Laurel, Star Poplar, MOP, Star Cherry I, Cherry I Super, Cherry II Super, Star Cherry III, Star Cherry IV, Cherry III Super, Cheri -IV Super (above, made by Maruzumi Paper), SHF (above, made by Toyo Pulp), TRP (above, made by Tokai Pulp), etc.

<Various films>
As the various films, all commonly used films can be used. For example, there are a polyester film, a polyolefin film, a polyvinyl chloride film, a polyvinylidene chloride film, and the like. Resin-coated paper that is photographic printing paper or YUPO paper that is synthetic paper can also be used.

<Various inkjet recording media>
As the various ink jet recording media, an ink receiving layer is formed on the surface using an absorbent support or a non-absorbent support as a base material. Examples of the ink receiving layer include a coating layer, a swelling layer, and a fine void layer.

  The swelling layer absorbs ink when the ink receiving layer made of a water-soluble polymer swells. The fine void layer is composed of inorganic or organic fine particles having a secondary particle size of about 20 to 200 nm and a binder, and fine voids of about 100 nm absorb ink.

  In recent years, an inkjet recording medium in which the above-mentioned fine void layer is provided on a base material using RC paper in which both sides of a paper base material are coated with an olefin resin is preferably used in terms of photographic images.

  As described above, the image forming apparatus of the present invention having a recording medium drying means has high ink fixability in various recording media when image formation is performed using the ink cured by crosslinking according to the present invention. This is an image forming apparatus which prevents feathering and bleeding, gives an ink jet image with high adhesion to a substrate and high printing quality, and has high diversity in recording media.

It is the schematic which shows an example of the image recording part which is the principal part of the image recording device of this invention. 1 is a schematic diagram of an image recording apparatus showing a first embodiment of the present invention. It is the schematic of the image recording device which is the 2nd embodiment of this invention provided with another drying means. FIG. 6 is a schematic view showing a third embodiment in the image forming apparatus of the present invention. FIG. 6 is a schematic view showing a fourth embodiment in the image forming apparatus of the present invention. 1 is a side view of an image forming apparatus having a plurality of heating rollers. It is a figure which shows the 5th embodiment in the image forming apparatus of this invention. It is a figure which shows another one form of the image forming apparatus which has a heating belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image recording part 2 Recording head 3 Irradiation means 4 Carriage 5 Guide member (linear guide)
6 Roller 7 Platen P Recording medium 10 Hood 11 Hot plate 12 Lamp 13 Reflector 14 Pressure roller 15 Heating means 16 Heating roller 17 Heating belt

Claims (9)

Recording an inkjet ink containing at least a colorant, water, and a polymer compound having a plurality of side chains in a hydrophilic main chain and capable of crosslinking between side chains by irradiation with active energy rays An image forming apparatus comprising: a recording head that ejects to a medium; an active energy ray irradiating unit that irradiates ink ejected with active energy rays; and a drying unit that dries the recording medium onto which the ink has been ejected. The image forming apparatus according to claim 1, wherein the drying unit is a unit that blows temperature-controllable air or warm air onto the recording medium on which the ink is ejected. The image forming apparatus according to claim 1, wherein the drying unit is a temperature-controllable hot plate that contacts a recording medium on which the ink is discharged. The image forming apparatus according to claim 1, wherein the drying unit is a unit that irradiates the recording medium with visible light or far infrared light. 5. The image forming apparatus according to claim 4, wherein means for irradiating the recording medium with visible light or far infrared light as the drying means is the same as the active energy ray irradiating means. The image forming apparatus according to claim 1, wherein the drying unit includes a roller or a roller pair capable of controlling a temperature that contacts the recording medium on which the ink is ejected. The image forming apparatus according to claim 1, wherein the drying unit includes a temperature-controllable belt suspended from a roller that comes into contact with the recording medium on which the ink is ejected. The image forming apparatus according to claim 1, wherein the temperature of the recording medium by the drying unit is 40 ° C. to 100 ° C. The image forming apparatus according to claim 1, wherein the temperature of the recording medium by the drying unit is determined based on environmental temperature and humidity.

Images