JP5673055B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus.

In recent years, inkjet recording methods are capable of recording high-definition images with a relatively simple apparatus, and have been rapidly developed in various fields. In addition, since there are various uses, a recording medium or ink suitable for each purpose is used. In particular, in recent years, the development of an ink jet recording apparatus having performance capable of withstanding light printing applications has been advanced by increasing the recording speed.
Here, in the light printing field, there is still a high demand for printing on printing paper, especially plain paper, and there is a high demand for high-speed and clear printing using the inkjet recording method. However, as a problem of the ink jet recording method in the light printing field, since only a relatively low viscosity ink can be emitted from the recording head, colors are mixed between different colors when recording on printing paper with low ink absorption. The phenomenon called bleed and the phenomenon called beading in which the shade of the color looks like a bead between the same colors occur, which causes the image quality to deteriorate.
In addition, when recording on plain paper with a high ink absorption speed, a phenomenon called feathering occurs where irregular bleeding occurs along the fiber of the paper, and a phenomenon of back-through where the ink penetrates to the back side also occurs. Even plain paper is a major cause of image quality degradation.

  In order to prevent this, the ink is given temperature sensitivity, and a temperature difference is provided between the recording head and the recording medium. There are attempts at temperature-sensitive thickening inks to prevent bleeding, beading, feathering, and the like while ensuring. For example, a technique has been developed in which an ink made of a substance that forms a solid resinous material by cooling after being heated at room temperature and the nozzles of the recording head are heated above the temperature at which the ink solidifies. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 3-71850

By the way, the ink solidified on the recording medium is in a bumpy state, and the actual condition is that the printed matter has no surface gloss.
An object of the present invention is to stabilize the gloss of an image to be formed even if an ink that changes in phase between a gel (or solid) and a liquid depending on temperature is used.

The invention according to claim 1 is an ink jet recording apparatus that uses a gel containing a gelling agent and that changes in phase between a gel state and a liquid state depending on the temperature, while holding the recording medium on the outer peripheral surface and rotating the recording medium. an image forming drum for conveying a plurality of recording heads for forming an image by ejecting the ink onto the recording medium held on said image forming drum, and passes the recording medium to the image forming drum feed And a downstream side of the recording medium delivery position by the supply unit and an upstream side of the recording head in the rotational direction of the image forming drum during image formation , and the outer periphery of the image forming drum from the outside heating the surface side, and a first heating means for heating the image forming drum and the imaging drum recording medium before holding image formation on the image forming drum , The heat capacity per unit surface area is ^{3000 [J / (m 2 ·} K)] or ^{9000 [J / (m 2 ·} K)] or less is the heat storage layer to form a outermost layer of the outer peripheral surface thereof, the heat storage It is a structure provided with the heat insulation layer located in the lower layer side of a layer, and the support body which supports the said thermal storage layer and the said heat insulation layer.

According to a second aspect of the present invention, there is provided a temperature sensor having the same configuration as that of the first aspect of the invention, and detecting at least one of a surface temperature of the image forming drum and a temperature of the first heating unit, and the temperature sensor And a controller for controlling the first heating means so that a temperature difference between the temperature of the recording medium during image formation and the gelation temperature of the ink falls within a predetermined range based on the detection result of And

The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and is upstream of the transfer position of the recording medium by the supply means in the rotation direction of the image forming drum during image formation. And a second heating unit that is disposed downstream of the discharge position of the recording medium after image formation and that heats the outer peripheral surface side from the outside of the image forming drum .

The invention described in claim 4 has the same configuration as that of the invention described in any one of claims 1 to 3, and the ink is an actinic ray curable ink that is cured by irradiation with energy rays, and an image. An energy ray is disposed on the upstream side of the discharge position of the recording medium after image formation and on the downstream side of the recording head in the rotation direction of the image forming drum at the time of formation, and the energy beam is applied to the recording medium on the image forming drum. An energy ray irradiating unit for irradiating is provided .

  The invention according to claim 5 has the same configuration as the invention according to any one of claims 1 to 4, and the thermal conductivity of the heat storage layer is 15 [W / (m · K)] or more. It is characterized by that.

  The invention according to claim 6 has the same configuration as that of the invention according to any one of claims 1 to 5, and the heat storage layer is formed of stainless steel or aluminum.

  The invention according to claim 7 has the same configuration as that of the invention according to any one of claims 1 to 6, and the thermal conductivity of the heat insulating layer is O.20 [W / (m · K)]. It is characterized as follows.

  The invention described in claim 8 has the same configuration as that of the invention described in any one of claims 1 to 7, and the thickness of the silent layer is set to 100 [μm] or more.

According to the present invention, the gloss of an image formed can be stabilized even when an ink that changes in phase between gel (or solid) and liquid is used depending on the temperature.
Further, according to the present invention, since the image forming drum has a heat storage layer on the heat insulating layer, heat is not released during heating from the outside, and the temperature rises quickly to realize rapid image formation, and heat is generated. Since it does not escape, the necessary amount of heat is maintained even when the recording medium P is held, the dot gloss is stabilized, and image formation can be performed with high image quality.

1 is a schematic diagram illustrating an internal configuration of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an internal configuration of an image forming unit provided in the ink jet recording apparatus of FIG. 1. FIG. 3 is a perspective view illustrating a schematic configuration of an image forming drum provided in the image forming unit of FIG. 2. It is sectional drawing which shows schematic structure of the heat roller with which the image formation part of FIG. 2 is equipped. FIG. 2 is a block diagram illustrating a main control configuration of the ink jet recording apparatus of FIG. 1. It is explanatory drawing which shows the modification of the heating means with which the inkjet recording device of FIG. 1 is equipped. 2 is a cross-sectional view showing a cross section perpendicular to a rotation center line of the image forming drum. It is the graph which showed the measurement result of the time required for the image forming drum to heat up to predetermined temperature about what adjusted the heat capacity per unit area by changing the thickness of the thermal storage layer of an image forming drum. It is the graph which showed the measurement result of the time required in order to heat up in the predetermined temperature range about what adjusted the raw material of the thermal storage layer of an image forming drum, and adjusted various heat conductivity.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a schematic diagram showing an internal configuration of an ink jet recording apparatus according to an embodiment of the present invention. As shown in FIG. 1, an inkjet recording apparatus 1 according to the present embodiment includes an image forming unit 2, a paper feeding unit 3 that feeds paper to the image forming unit 2, and a recording medium on which an image is formed by the image forming unit 2. And an accumulating unit 4 for accumulating P.

  The paper feeding unit 3 includes a paper feeding tray 31 that stores the recording medium P, a paper feeding conveyance unit 32 that conveys the recording medium P from the paper feeding tray 31 to the image forming unit 2, and a recording medium in the paper feeding tray 31. And a supply unit 33 that supplies P to the sheet feeding conveyance unit 32. The paper feed transport unit 32 includes a pair of paper feed transport rollers 321 and 322, and a paper feed transport belt 323 is stretched around the paper feed transport rollers 321 and 322. The sheet feeding conveyor belt 323 carries the recording medium P supplied from the sheet feeding tray 31 by the supply unit 33 and conveys it to the image forming unit 2.

  The stacking unit 4 includes a storage tray 41 that stores the recording medium P on which an image has been formed, and a stacking transport unit 42 that transports the recording medium P from the image forming unit 2 to the storage tray 41. The accumulation transport section 42 is provided with a plurality of accumulation transport chain sprockets 421, 422, and 423. Among the plurality of stacking transport chain sprockets 421 to 423, one stacking transport chain sprocket 421 is disposed in the image forming unit 2, and the remaining stacking transport chain sprockets 422 and 423 are disposed in the stacking unit 4. Has been placed. The recording medium P on which an image is formed by the image forming unit 2 is conveyed while being held on the stacking conveyance belt 424 by the stacking claw unit 425, and is held by the stacking claw unit 425 when it is on the storage tray 41. Is released and stored in the storage tray 41.

  FIG. 2 is a schematic diagram illustrating an internal configuration of the image forming unit 2. As shown in FIG. 2, in order to form an image on the recording medium P, the image forming unit 2 holds the recording medium P on the surface and conveys it while rotating, and the paper feeding unit 3. A transfer drum 22 that transfers the conveyed recording medium P to the image forming drum 21 is provided.

  In order to hold the recording medium P on its outer peripheral surface, the transfer drum 22 has a plurality of claw portions 221 that sandwich one end of the recording medium P, and an adsorption portion that adsorbs the recording medium P to the outer peripheral surface (not shown). And. The suction portion is adapted to suck the recording medium P on the outer peripheral surface of the transfer drum 22 by electrostatic suction or suction. The transfer drum 22 has a part of the outer periphery thereof close to the image forming drum 21, and the recording medium P is transferred to the image forming drum 21 at this close portion.

FIG. 3 is a perspective view showing a schematic configuration of the image forming drum 21. As shown in FIG. 3, since the image forming drum 21 holds the recording medium P on its outer peripheral surface, the image forming drum 21 attracts the recording medium P to the outer peripheral surface and a plurality of claw portions 211 that sandwich one end of the recording medium P. And a plurality of suction holes 212 for the purpose.
A plurality of claw portions 211 are accommodated in the recess 213 formed on the outer peripheral surface of the image forming drum 21 along the axial direction. The front end portion 214 of the claw portion 211 can be freely contacted and separated from the outer peripheral surface of the image forming drum 21, and the front end portion of the recording medium P is formed by the front end portion 214 of the claw portion 211 and the outer peripheral surface of the image forming drum 21. , The recording medium P is held on the outer peripheral surface of the image forming drum 21.

The suction hole 212 sucks the recording medium P on the outer peripheral surface by applying a suction force from, for example, the suction pump 215 (see FIG. 5) to the recording medium P on the outer peripheral surface of the image forming drum 21. is there. Here, when the recording medium P is installed on the outer peripheral surface of the image forming drum 21, a plurality of suction holes 212 are formed only in a region P3 that overlaps a portion P2 that is out of the image forming region P1 of the recording medium P. Yes. The plurality of suction holes 212 are arranged in a pattern having, for example, a blue noise characteristic.

As shown in FIG. 2, a plurality of recording heads 5, an energy ray irradiation unit 6, a drum temperature sensor 9, a first heat roller 7, and a second heat roller 8 are arranged around the image forming drum 21.
The recording heads 5 are line type recording heads, and a plurality of recording heads 5 are arranged on the image forming drum 21 in the circumferential direction, that is, in the conveyance direction Y of the recording medium P. Each recording head 5 extends over the entire length of the image forming drum 21. In the inkjet recording apparatus 1 according to the present embodiment, a total of four recording heads 5 are provided so that ink of four colors of black (K), yellow (Y), magenta (M), and cyan (C) can be ejected. It has been.

As shown in FIG. 2, an energy beam irradiation unit 6 that irradiates energy beams such as ultraviolet rays, for example, is disposed immediately downstream in the conveyance direction Y of the recording medium P in the plurality of recording heads 5. The energy ray irradiation unit 6 extends over the entire length of the image forming drum 21 and irradiates the recording medium P on the image forming drum 21 with energy rays.
When ultraviolet rays are used as the energy rays, examples of the ultraviolet irradiation light source include fluorescent tubes (low pressure mercury lamps, germicidal lamps), cold cathode tubes, ultraviolet lasers, low pressures having medium operating pressures from several hundred Pa to 1 MPa, medium pressures, A high-pressure mercury lamp, a metal halide lamp, an LED, and the like can be mentioned. From the viewpoint of curability, a light source capable of emitting high-intensity UV light with an illuminance of 100 mW / cm ² or more such as a high-pressure mercury lamp, a metal halide lamp, and an LED is preferable. Among them, an LED with low power consumption is preferable, but not limited thereto.

An accumulation transport chain sprocket 421 of the accumulation transport section 42 is disposed immediately downstream of the energy beam irradiation section 6 in the transport direction Y. Further, a part of the outer periphery of the stacking transport chain sprocket 421 is close to the image forming drum 21 via the stacking transport belt 424, and the recording medium P is transported for stacking from the image forming drum 21 at this close portion. It is designed to be transferred to the belt 424.
Further, a drum temperature sensor 9 that measures the surface temperature of the image forming drum 21 is disposed immediately downstream in the transport direction Y of the stacking transport chain sprocket 421.

  The first heat roller 7 is a first heating unit according to the present invention, and is disposed immediately downstream of the transfer drum 22 in the transport direction Y, that is, between the transfer drum 22 and the recording head 5. Part of the first heat roller 7 is in contact with the outer peripheral surface of the image forming drum 21, and the recording medium P is interposed between the first heat roller 7 and the image forming drum 21 during image formation.

  The second heat roller 8 is a second heating unit according to the present invention, and is disposed on the opposite side of the first heat roller 7 with the delivery drum 22 as a reference. A part of the second heat roller 8 is in contact with the outer peripheral surface of the image forming drum 21.

FIG. 4 is a cross-sectional view showing a schematic configuration of the first heat roller 7 and the second heat roller 8. As shown in FIG. 4, the first heat roller 7 and the second heat roller 8 include hollow pipes 71 and 81 made of a metal such as aluminum, and silicon rubber or the like covering the entire circumference of the hollow pipes 71 and 81. The elastic bodies 72 and 82 and the heat sources 73 and 83 such as halogen heaters that are built in the hollow pipes 71 and 81 and heat the hollow pipes 71 and 81 and the elastic bodies 72 and 82 are provided.
The surfaces of the elastic bodies 72 and 82 may be coated with a material having good slipperiness (for example, a PFA tube) to enhance durability.

FIG. 5 is a block diagram showing a main control configuration of the inkjet recording apparatus 1. As shown in FIG. 5, the control unit 10 of the inkjet recording apparatus 1 includes a transfer drum drive source 11 that rotates the transfer drum 22, an image forming drum drive source 12 that rotates the image forming drum 21, and a paper feed unit 3. The paper feed unit drive source 13 that drives each drive unit, the stack unit drive source 14 that drives each drive source of the stack unit 4, the print head driver 15 that drives the print head 5, and the type of print medium are input. Recording medium type input unit 16, roller temperature sensor 17 that detects the temperature of the first heat roller 7, first heat roller 7, second heat roller 8, drum temperature sensor 9, and energy beam irradiation unit 6. The suction pump 215 is electrically connected. In addition, an image creation device 19 such as a PC is connected to the control unit 10 via an I / F 18 so as to be communicable.
The control unit 10 includes a CPU (Central Processing Unit) and a memory, and controls each component of the inkjet recording apparatus 1. The memory stores image data transferred from the image creating device 19, a program for controlling each component of the inkjet recording device 1, a heating temperature for each type of recording medium, and the like. The CPU performs an operation based on image data or a program stored in the memory, and transmits a control signal to each component based on the operation result.

  The ink used in the present invention is an actinic ray curable ink that cures when irradiated with an energy ray (active ray). This actinic ray curable ink contains 1% by mass or more and less than 10% by mass of a gelling agent, and is characterized by reversible sol-gel phase transition depending on temperature. The sol-gel phase transition referred to in the present invention is a solution state having fluidity at a high temperature, but by cooling to below the gelation temperature, the entire liquid is gelled and changed to a state in which the fluidity has been lost. Although it is in a state in which it loses fluidity, it refers to a phenomenon in which it returns to a liquid state with fluidity when heated to a temperature above the solation temperature.

In the present invention, gelation refers to interactions such as a lamellar structure, a polymer network formed by non-covalent bonds or hydrogen bonds, a polymer network formed by a physical aggregation state, and an aggregate structure of fine particles. This refers to a structure in which substances lose their independent motion due to the interaction of microcrystals, etc., and indicate a solidified, semi-solidified, or thickened state with a sudden increase in viscosity or elasticity. Point to. Further, solification refers to a state in which the interaction formed by the gelation is eliminated and the liquid state is changed to a fluid state. In addition, the solation temperature in the present invention is a temperature at which fluidity is exhibited by solification when the gelled ink is heated, and the gelation temperature is the cooling of the ink in the sol state. It refers to the temperature at which gelation occurs and fluidity decreases.
The actinic ray curable ink that undergoes the sol-gel phase transition is in a liquid state at a high temperature, and thus can be ejected by an ink jet recording head. When recording using this high-temperature actinic ray curable ink, after the ink droplets have landed on the recording medium, the ink is quickly cooled by natural cooling due to the temperature difference, and as a result, adjacent dots are coalesced. Can prevent image quality deterioration. However, when the solidification force of the ink droplet is strong, the dots are isolated, resulting in unevenness in the image area, which may lead to an uneven glossiness such as an extremely low glossiness or an unnatural sparkle. As a result of intensive studies by the inventors, by setting the solidification force of the ink droplets, the gelation temperature of the ink, and the temperature of the recording medium within the following ranges, it is possible to prevent the ink droplets from coalescing and to prevent image quality deterioration. And found that the most natural glossiness can be obtained. That is, an ink containing 0.1% by mass or more and less than 10% by mass of a gelling agent uses an ink having a viscosity at 25 ° C. of 10 ² mPa · s or more and less than 10 ⁵ mPa · s, and the ink using the gelling agent By controlling the difference between the gelation temperature (Tgel) and the surface temperature (Ts) of the recording medium at 5 to 15 ° C., printing can be achieved with both high image quality and a natural glossiness. It becomes possible. In this case, the temperature control range of the medium corresponds to 42 to 48 ° C.

  The inventors consider this reason as follows. After ink droplets have landed on the recording medium and before the adjacent ink droplets landed, the ink solidifies, resulting in a decrease in gloss and an unnatural sparkle in the image area. On the other hand, if the ink droplets solidify after a while after the adjacent ink droplets land and coalesce, the droplets come close to each other, leading to extreme image quality degradation. As a result of intensive studies by the inventors, it has been found that by controlling the viscosity at the time of ink landing, liquid coalescence can be prevented, and adjacent ink droplets can be appropriately leveled to obtain a natural gloss feeling. .

Moreover, the said base material temperature range is used by using the ink in which the viscosity in 25 degreeC of the ink containing 0.1 mass% or more and less than 10 mass% of gelling agents is 10 < ² > mPa * s or more and less than 10 < ⁵ > mPa * s. Viscosity control is possible, and both image quality and natural gloss can be achieved. The reason is presumed as follows. With an ink having a viscosity at 25 ° C. of less than 10 ² mPa · s, the viscosity is insufficient to prevent coalescence of liquids, and the image quality deteriorates in the above temperature range. In addition, with an ink having a viscosity at 25 ° C. of 10 ⁵ mPa · s or more, the viscosity after gelation is high, and the viscosity tends to increase greatly during the cooling process, and the viscosity is controlled to an appropriate level in the above temperature range. This makes it difficult to achieve gloss reduction. In addition, since the ink of the present invention becomes a viscous gel having an appropriate viscosity after gelation, it becomes possible to more appropriately suppress the solidification force of dots, and as a result, the image quality with a more natural glossiness can be obtained. I think it will be obtained.

The gloss homogeneity in the present invention does not indicate an absolute gloss value, for example, a 60-degree specular gloss value, but an unnatural sparkle or unnecessary due to a microscopic gloss difference on an image. A state in which the gloss is not uniform in a part of the image, such as low gloss reduction or streaky gloss unevenness, is not observed, and the gloss on the entire surface of the image, particularly the solid print portion, is uniform.
By using the actinic ray curable ink described in the present invention, adjusting the difference between the gel temperature (Tgel) of the ink and the surface temperature (Ts) of the recording medium to 5 to 15 ° C., there is no deterioration in image quality, It is possible to form images with excellent sharpness of fine lines such as letters and natural glossiness, but by adjusting the temperature of the recording medium to a range of 5 to 10 ° C, a better image can be obtained. It becomes possible to form.

Hereinafter, the actinic ray curable ink composition used in the present invention will be sequentially described.
(Gelling agent)
In the present invention, gelation refers to interactions such as a lamellar structure, a polymer network formed by non-covalent bonds or hydrogen bonds, a polymer network formed by a physical aggregation state, and an aggregate structure of fine particles. This refers to a structure in which substances lose their independent motion due to the interaction of microcrystals, etc., and indicate a solidified, semi-solidified, or thickened state with a sudden increase in viscosity or elasticity. Point to.
In general, a gel becomes a fluid solution (sometimes called a sol) by heating, a thermoreversible gel that returns to the original gel when cooled, and once gelled, it can be reheated even if heated. There is a heat irreversible gel that does not return. The gel formed by the oil gelling agent according to the present invention is preferably a thermoreversible gel from the viewpoint of preventing clogging in the head.
In the actinic ray curable ink of the present invention, the gelation temperature (phase transition temperature) of the ink is preferably 40 ° C. or higher and lower than 100 ° C., more preferably 45 ° C. or higher and 70 ° C. or lower. Considering the temperature in the summer environment, if the phase transition temperature of the ink is 40 ° C. or higher, stable ejection can be obtained without being affected by the printing environment temperature when ejecting ink droplets from the recording head. If the temperature is less than 90 ° C., it is not necessary to heat the inkjet recording apparatus to an excessively high temperature, and the load on the head of the inkjet recording apparatus and the members of the ink supply system can be reduced.

The gelation temperature as used in the present invention means a temperature at which the viscosity suddenly changes from a fluid solution state to a gel state, and the gel transition temperature, gel dissolution temperature, phase transition temperature, sol-gel phase It is synonymous with terms called transition temperature and gel point.
In the present invention, the method for measuring the gelation temperature of the ink is, for example, using various rheometers (for example, a stress control type rheometer using a cone plate, Physica MCR series, manufactured by Anton Paar) and using a high temperature ink in a sol state It can be determined from a viscosity curve obtained while changing the temperature at a low shear rate and a viscoelastic curve obtained by measuring the temperature change of dynamic viscoelasticity. In addition, a method in which a small iron piece sealed in a glass tube is placed in a dilatometer and a phase transition point is defined as a point at which the ink liquid does not naturally fall in response to a temperature change (J. Polym. Sci., 21, 57). (1956)), a method of measuring the temperature at which an aluminum cylinder naturally falls when an aluminum cylinder is placed on the ink and changing the gel temperature as a gelation temperature (Journal of Japanese Society of Rheology, Vol. 17, 86 ( 1989)). As a simple method, a gel-like test piece is placed on a heat plate, the heat plate is heated, the temperature at which the shape of the test piece collapses is measured, and this can be obtained as the gelation temperature. The gelation temperature (phase transition temperature) of the ink can be adjusted by changing the type of gelling agent used, the amount of gelling agent added, and the type of actinic ray curable monomer.

In the ink of the present invention, the viscosity at 25 ° C. of the ink is preferably 10 ² mPa · s or more and less than 10 ⁵ mPa · s, more preferably 10 ³ mPa · s or more and less than 10 ⁴ mPa · s. If the ink viscosity is 10 ² mPa · s or more, deterioration of image quality due to dot coalescence can be prevented, and if it is less than 10 ⁵ mPa · s, by controlling the surface temperature of the recording medium upon ink landing, A uniform gloss can be obtained by appropriate leveling. The viscosity of the ink can be appropriately adjusted by changing the type of gelling agent used, the amount of gelling agent added, and the type of actinic ray curable monomer. The viscosity as used in the present invention is measured at a shear rate of 11.7 s ⁻¹ using a stress control type rheometer using a cone plate, Physica MCR series, manufactured by Anton Paar).
The gelling agent used in the ink according to the present invention may be a high molecular compound or a low molecular compound, but a low molecular compound is preferable from the viewpoint of ink jet ejection properties.

Specific examples of the gelling agent that can be used in the ink according to the present invention are shown below, but the present invention is not limited only to these compounds.
Specific examples of the polymer compound preferably used in the present invention include fatty acid inulins such as inulin stearate, fatty acid dextrins such as dextrin palmitate and dextrin myristate (available from Chiba Flour as the Leopard series), eicosane behenate Examples include glyceryl diacid, eicosane behenate polyglyceryl (available from Nisshin Oilio as Nomcoat series), and the like.
Specific examples of the low molecular weight compound preferably used in the present invention include, for example, low molecular weight oil gelling agents described in JP-A-2005-126507, JP-A-2005-255821, and JP-A-2010-1111790, N -Lauroyl-L-glutamic acid dibutylamide, N-2 ethylhexanoyl-L-glutamic acid dibutylamide and other amide compounds (available from Ajinomoto Fine-Techno), 1,3: 2,4-bis-O-benzylidene-D -Dibenzylidene sorbitols such as Glucitol (available from Gelol D Shin Nippon Rika), petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam, candelilla wax, carnauba wax, rice wax, wood wax, Jojoba oil, jojoba solid wax, ho Plant waxes such as hover esters, animal waxes such as beeswax, lanolin and whale wax, mineral waxes such as montan wax and hydrogenated wax, hardened castor oil or hardened castor oil derivatives, montan wax derivatives, paraffin wax Derivatives, modified waxes such as microcrystalline wax derivatives or polyethylene wax derivatives, higher fatty acids such as behenic acid, arachidic acid, stearic acid, palmitic acid, myristic acid, lauric acid, oleic acid, erucic acid, stearyl alcohol, Higher alcohols such as behenyl alcohol, hydroxystearic acid such as 12-hydroxystearic acid, 12-hydroxystearic acid derivatives, lauric acid amide, stearic acid amide, behenic acid amide, oleic acid acid Fatty acid amides such as nicotinic acid amide, ricinoleic acid amide, 12-hydroxystearic acid amide (for example, Nikka Amide series manufactured by Nippon Kasei Co., Ltd., ITOWAX series manufactured by Ito Oil Co., Ltd., FATTYAMID series manufactured by Kao Corporation), N-substituted fatty acid amides such as N-stearyl stearamide, N-oleyl palmitate, N, N'-ethylenebisstearylamide, N, N'-ethylenebis12-hydroxystearylamide, N, N'- Special fatty acid amides such as xylylene bisstearyl amide, higher amines such as dodecylamine, tetradecylamine or octadecylamine, stearyl stearic acid, oleyl palmitic acid, glycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol Fatty acid ester compounds such as fatty acid esters, ethylene glycol fatty acid esters, polyoxyethylene fatty acid esters (for example, EMALLEX series manufactured by Nihon Emulsion, Rikumar series manufactured by RIKEN VITAMIN, POEM series manufactured by RIKEN VITAMIN), sucrose Synthetic waxes such as stearic acid and sucrose palmitic acid (eg, Ryoto Sugar Ester series manufactured by Mitsubishi Chemical Foods), polyethylene wax, α-olefin maleic anhydride copolymer wax, and polymerizable wax (UNILIN series Baker-Petrolite), dimer acid, dimer diol (PRIPOR series CRODA) and the like. Moreover, said gelling agent may be used independently and may be used in mixture of 2 or more types.

  The ink of the present invention contains a gelling agent, and immediately after landing on the recording medium after being ejected from the ink jet recording head, it becomes a gel state, and dot mixing and dot coalescence are suppressed and high-speed printing is performed. It becomes possible to form a high image quality at that time, and thereafter, it is cured by irradiation with actinic rays to be fixed on the recording medium to form a strong image film. As content of a gelatinizer, 1 mass% or more and less than 10 mass% are preferable, and 2 mass% or more and less than 7 mass% are more preferable. By setting the amount to 1% by mass or more, gel formation is sufficient, deterioration of image quality due to dot coalescence can be suppressed, and oxygen is used in a photo radical curing system by thickening ink droplets due to gel formation. Photocurability can be reduced due to inhibition, and by setting it to less than 10% by mass, deterioration of the cured film and deterioration of inkjet ejection properties due to uncured components after irradiation with actinic rays can be reduced.

(Actinic ray curable composition)
The ink of the present invention is characterized by containing an actinic ray curable composition that cures with actinic rays together with a gelling agent and a colorant.
The actinic ray curable composition (hereinafter also referred to as a photopolymerizable compound) used in the present invention will be described.
Examples of the actinic rays in the present invention include electron beams, ultraviolet rays, α rays, γ rays, X rays, etc., but they are dangerous to human bodies and easy to handle, and their use is widespread industrially. UV light or electron beam is preferred. In the present invention, ultraviolet rays are particularly preferable.
In the present invention, the photopolymerizable compound that is crosslinked or polymerized by irradiation with actinic rays can be used without particular limitation, but among them, a photocationically polymerizable compound or a photoradical polymerizable compound is preferably used.

(Cationically polymerizable compound)
As the photo cationic polymerizable monomer, various known cationic polymerizable monomers can be used. For example, JP-A-6-9714, JP-A-2001-31892, JP-A-2001-40068, JP-A-2001-55507, JP-A-2001-310938, JP-A-2001-310937, JP-A-2001-220526 Epoxy compounds, vinyl ether compounds, oxetane compounds and the like exemplified in each of the above publications.
In the present invention, for the purpose of suppressing the shrinkage of the recording medium during ink curing, it contains at least one oxetane compound as a photopolymerizable compound and at least one compound selected from an epoxy compound and a vinyl ether compound. Is preferred.

A preferable aromatic epoxide is a di- or polyglycidyl ether produced by the reaction of a polyhydric phenol having at least one aromatic nucleus or an alkylene oxide adduct thereof and epichlorohydrin, such as bisphenol A or an alkylene oxide thereof. Examples thereof include di- or polyglycidyl ethers of adducts, di- or polyglycidyl ethers of hydrogenated bisphenol A or alkylene oxide adducts thereof, and novolak type epoxy resins. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.
As the alicyclic epoxide, cyclohexene oxide or cyclopentene obtained by epoxidizing a compound having at least one cycloalkane ring such as cyclohexene or cyclopentene ring with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Oxide-containing compounds are preferred.
Preferred aliphatic epoxides include di- or polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, and typical examples thereof include diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol or Diglycidyl ether of alkylene glycol such as diglycidyl ether of 1,6-hexanediol, polyglycidyl ether of polyhydric alcohol such as di- or triglycidyl ether of glycerin or its alkylene oxide adduct, polyethylene glycol or its alkylene oxide adduct Of polyalkylene glycols such as diglycidyl ether, polypropylene glycol or diglycidyl ether of its alkylene oxide adduct Glycidyl ether, and the like. Here, examples of the alkylene oxide include ethylene oxide and propylene oxide.
Among these epoxides, in view of fast curability, aromatic epoxides and alicyclic epoxides are preferable, and alicyclic epoxides are particularly preferable. In the present invention, one of the epoxides may be used alone, or two or more may be used in appropriate combination.
Examples of the vinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n-propyl Pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -o- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether.
Among these vinyl ether compounds, in consideration of curability, adhesion, and surface hardness, di- or trivinyl ether compounds are preferable, and divinyl ether compounds are particularly preferable. In the present invention, one of the above vinyl ether compounds may be used alone, or two or more thereof may be used in appropriate combination.

The oxetane compound referred to in the present invention is a compound having an oxetane ring, and any known oxetane compound as described in JP-A Nos. 2001-220526 and 2001-310937 can be used.
In the oxetane compound that can be used in the present invention, when a compound having 5 or more oxetane rings is used, the viscosity of the ink composition increases, which makes it difficult to handle, and the glass transition temperature of the ink composition is high. Therefore, the tackiness of the cured product obtained may not be sufficient. The compound having an oxetane ring used in the present invention is preferably a compound having 1 to 4 oxetane rings.
Examples of the compound having an oxetane ring that can be preferably used in the present invention include compounds represented by general formula (1) described in paragraph No. (0089) of JP-A-2005-255821, and the same publication. The general formula (2), the general formula (7) of the paragraph number (0107), the general formula (8) of the paragraph number (0109), and the general formula of the paragraph number (0166) described in the paragraph number (0092) of The compound represented by (9) etc. can be mentioned.
Specific examples thereof include the exemplified compounds 1 to 6 described in paragraph numbers (0104) to (0119) and the compounds described in paragraph number (0121) of the publication.

(Radically polymerizable compound)
Next, the radical polymerizable compound will be described.
Various known radically polymerizable monomers can be used as the photoradical polymerizable monomer. For example, photocurable materials using photopolymerizable compositions described in JP-A-7-159983, JP-B-7-31399, JP-A-8-224982, and JP-A-10-863 Cationic polymerization type photocurable resins are known, and recently, photocationic polymerization type photocurable resins sensitized to a long wavelength region longer than visible light are disclosed in, for example, JP-A-6-43633. It is disclosed in the Kaihei 8-324137 publication.
The radical polymerizable compound is a compound having an ethylenically unsaturated bond capable of radical polymerization, and may be any compound as long as it has at least one ethylenically unsaturated bond capable of radical polymerization in the molecule. , Oligomers, polymers and the like having a chemical form. Only one kind of radically polymerizable compound may be used, or two or more kinds thereof may be used in combination at an arbitrary ratio in order to improve desired properties.
Examples of compounds having an ethylenically unsaturated bond capable of radical polymerization include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid and their salts, esters, urethanes, amides. And radically polymerizable compounds such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated urethanes.
Any known (meth) acrylate monomer and / or oligomer can be used as the radical polymerizable compound of the present invention. The term “and / or” as used in the present invention means that it may be a monomer, an oligomer, or both. The same applies to the items described below.

  As the compound having a (meth) acrylate group, for example, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isomyristyl acrylate, isostearyl acrylate, 2-ethylhexyl-diglycol acrylate, 2-hydroxybutyl acrylate 2-acryloyloxyethyl hexahydrophthalic acid, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2- Hydroxyethyl acrylic 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalate Monofunctional monomers such as acid, lactone-modified flexible acrylate, t-butylcyclohexyl acrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1, 4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, Bifunctional monomers such as methylol-tricyclodecane diacrylate, PO adduct diacrylate of bisphenol A, neopentyl glycol diacrylate hydroxypivalate, polytetramethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, penta Trifunctional or more polyfunctional such as erythritol tetraacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin propoxytriacrylate, caprolactone-modified trimethylolpropane triacrylate, pentaerythritol ethoxytetraacrylate, caprolactam-modified dipentaerythritol hexaacrylate Monomer. In addition, polymerizable oligomers can be blended in the same manner as the monomer. Examples of the polymerizable oligomer include epoxy acrylate, aliphatic urethane acrylate, aromatic urethane acrylate, polyester acrylate, and linear acrylic oligomer. More specifically, Yamashita Shinzo, “Cross-linking agent handbook” (1981 Taiseisha); Kato Kiyosumi, “UV / EB curing handbook (raw material)” (185, Polymer publication society); Study Group, “Application and Market of UV / EB Curing Technology”, page 79 (1989, CMC); Eiichiro Takiyama, “Polyester Resin Handbook”, (1988, Nikkan Kogyo Shimbun) Commercially available products or radically polymerizable or crosslinkable monomer oligomers and polymers known in the industry can be used.

Among the above monomers, isoamyl acrylate, stearyl acrylate, lauryl acrylate, octyl acrylate, decyl acrylate, isomyristyl acrylate are particularly preferred from the viewpoints of sensitization, skin irritation, eye irritation, mutagenicity, toxicity, etc. , Isostearyl acrylate, ethoxydiethylene glycol acrylate, methoxypolyethylene glycol acrylate, methoxypropylene glycol acrylate, isobornyl acrylate, lactone-modified flexible acrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, dipentaerythritol Hexaacrylate, ditrimethylolpropane tetraacrylate, glycerin Po carboxymethyl triacrylate, caprolactone modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, caprolactam modified dipentaerythritol hexaacrylate preferred.
Furthermore, among these, stearyl acrylate, lauryl acrylate, isostearyl acrylate, ethoxydiethylene glycol acrylate, isobornyl acrylate, tetraethylene glycol diacrylate, glycerin propoxy triacrylate, cowprolactone-modified trimethylolpropane triacrylate, caprolactam-modified dipenta Erythritol hexaacrylate is particularly preferred.

In the present invention, a vinyl ether monomer and / or oligomer and a (meth) acrylate monomer and / or oligomer may be used in combination as the polymerizable compound. Examples of the vinyl ether monomer include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, Di- or trivinyl ether compounds such as methylolpropane trivinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexane dimethanol monovinyl ether, n- B pills vinyl ether, isopropyl vinyl ether, isopropenyl ether -o- propylene carbonate, dodecyl vinyl ether, diethylene glycol monovinyl ether, and octadecyl vinyl ether. When a vinyl ether oligomer is used, a bifunctional vinyl ether compound having a molecular weight of 300 to 1000 and having 2 to 3 ester groups in the molecule is preferable. For example, compounds available as a VEctomer series of ALDRICH, VEctomer 4010, VEctomer 4020, VEctomer 4040 , VEctomer 4060, VEctomer 5015 and the like are preferable, but not limited thereto.
In the present invention, various vinyl ether compounds and maleimide compounds can be used in combination as the polymerizable compound. Examples of maleimide compounds include N-methylmaleimide, N-propylmaleimide, N-hexylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N, N′-methylenebismaleimide, and polypropylene glycol-bis. (3-maleimidopropyl) ether, tetraethylene glycol-bis (3-maleimidopropyl) ether, bis (2-maleimidoethyl) carbonate, N, N ′-(4,4′-diphenylmethane) bismaleimide, N, N ′ -2,4-tolylene bismaleimide or a polyfunctional maleimide compound which is an ester compound of maleimide carboxylic acid and various polyols disclosed in JP-A-11-124403. As far as There.
The addition amount of the cationically polymerizable compound and the radically polymerizable compound is preferably 1 to 97% by mass, more preferably 30 to 95% by mass.

(Each component of ink)
Next, the components of the ink of the present invention excluding the above items will be described.
(Color material)
In the ink of the present invention, a dye or a pigment can be used without limitation as a color material constituting the ink, but a pigment having good dispersion stability with respect to the ink component and excellent weather resistance is used. It is preferable. Although it does not necessarily limit as a pigment, For example, the organic or inorganic pigment of the following number described in a color index can be used for this invention.
Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 43, 48: 1, 48: 2, 48: 3, 48: 4, 48: 5, 49: 1, and 53: 1. 57: 1, 57: 2, 58: 4, 63: 1, 81, 81: 1, 81: 2, 81: 3, 81: 4, 88, 104, 108, 112, 122, 123, 144, 146 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, Pigment Orange 13 16, 20, 36,
As the blue or cyan pigment, Pigment Blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17-1, 22, 27, 28, 29, 36, 60 ,
Examples of green pigments include Pigment Green 7, 26, 36, 50,
As the yellow pigment, Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193,
As the black pigment, Pigment Black 7, 28, 26 and the like can be used according to the purpose.

  Specific product names include, for example, chromo fine yellow 2080, 5900, 5930, AF-1300, 2700L, chromo fine orange 3700L, 6730, chromo fine scarlet 6750, chromo fine magenta 6880, 6886, 6891N, 6790, 6887. , Chromofine Violet RE, Chromofine Red 6820, 6830, Chromofine Blue HS-3, 5187, 5108, 5197, 5085N, SR-5020, 5026, 5050, 4920, 4927, 4937, 4824, 4933GN-EP, 4940, 4973, 5205, 5208, 5214, 5221, 5000P, Chromofine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Black Fine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400 (B), 2500, 2600, ZAY-260, 2700 (B), 2770, Seika Fast Red 8040, C405 (F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seika Fast Carmine 6B1476T-7, 1383LT, 3840, 3870, Seika Fast Bordeaux 10B-430, Seika Light Rose R40, Seika Light Violet B800, 7805, Seika Fast Maroon 460N, Seika Fast Orange 900, 2900, Seika Light Blue C7 8, A612, cyanine blue 4933M, 4933GN-EP, 4940, 4973 (manufactured by Dainichi Seikagaku), KET Yellow 401, 402, 403, 404, 405, 406, 416, 424, KET Orange 501, KET Red 301, 302 , 303, 304, 305, 306, 307, 308, 309, 310, 336, 337, 338, 346, KET Blue 101, 102, 103, 104, 105, 106, 111, 118, 124, KET Green 201 (large Nippon Ink Chemical Co., Ltd.), Colortex Yellow 301, 314, 315, 316, P-624, 314, U10GN, U3GN, UNN, UA-414, U263, Finecol Yellow T-13, T-05, Pi ment Yellow 1705, Colortex Orange 202, Colortex Red 101, 103, 115, 116, D3B, P-625, 102, H-1024, 105C, UFN, UCN, UBN, U3BN, URN, UGN, UG276, U456, U457, 105C USN, Colortex Maroon 601, Colortex Brown B610N, Colortex violet 600, Pigment Red 122, Colortex Blue 516, 517, 518, 519, A818, P-908, 510, Colortex Green 402, 403B, Col. , Lionol B lue FG7330, FG7350, FG7400G, FG7405G, ES, ESP-S (manufactured by Toyo Ink), Toner Magenta E02, Permanent RubinF6B, Toner Yellow HG, Permanent Yellow GG-02, HostaBem G2 , Hostaper Pink E, Hostaperm Blue B2G (manufactured by Clariant), carbon black # 2600, # 2400, # 2350, # 2200, # 1000, # 990, # 980, # 970, # 960, # 950, # 850, MCF88 # 750, # 650, MA600, MA7, MA8, MA11, MA100, MA100R, MA77, # 52, # 50, # 47, # 45, # 45L, # 40, # 33, # 32, # 30, # 25, # 20, # 10, # 5, # 44, CF9 (Mitsubishi Chemical) Can be mentioned.

For the dispersion of the pigment, for example, a ball mill, sand mill, attritor, roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, pearl mill, wet jet mill, paint shaker, or the like can be used.
Further, a dispersing agent can be added when dispersing the pigment. As the dispersant, a polymer dispersant is preferably used. Examples of the polymer dispersant include Avecia's Solsperse series and Ajinomoto Fine-Techno's PB series. Furthermore, the following are mentioned.
Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, a high molecular weight unsaturated acid ester, Polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl Examples thereof include phenyl ether, stearylamine acetate, and pigment derivatives.

Specific examples include “Anti-Terra-U (polyaminoamide phosphate)”, “Anti-Terra-203 / 204 (high molecular weight polycarboxylate)” manufactured by BYK Chemie, “Disperbyk-101 (polyaminoamide phosphate). And acid ester), 107 (hydroxyl group-containing carboxylic acid ester), 110 (copolymer containing an acid group), 130 (polyamide), 161, 162, 163, 164, 165, 166, 170 (polymer copolymer) ”,“ 400 ”,“ Bykumen ”(high molecular weight unsaturated acid ester),“ BYK-P104, P105 (high molecular weight unsaturated acid polycarboxylic acid) ”,“ P104S, 240S (high molecular weight unsaturated acid polycarboxylic acid and Silicone) ”,“ Lactimon (long-chain amine, unsaturated polycarboxylic acid and silico) ) ”.
Also, “Efka CHEMICALS” “Efka 44, 46, 47, 48, 49, 54, 63, 64, 65, 66, 71, 701, 764, 766”, “Efka Polymer 100 (modified polyacrylate), 150 (aliphatic) System modified polymer), 400, 401, 402, 403, 450, 451, 452, 453 (modified polyacrylate), 745 (copper phthalocyanine system) "; Kyoei Chemical Co., Ltd." Floren TG-710 (urethane oligomer) "," “Flonon SH-290, SP-1000”, “Polyflow No. 50E, No. 300 (acrylic copolymer)”; “Disparon KS-860, 873SN, 874 (polymer dispersing agent), # 2150, manufactured by Enomoto Kasei Co., Ltd. (Aliphatic polyvalent carboxylic acid), # 7004 (polyether ester type) "and the like It is.
Furthermore, “Demol RN, N (Naphthalenesulfonic acid formalin condensate sodium salt), MS, C, SN-B (aromatic sulfonic acid formalin condensate sodium salt), EP”, “Homogenol L-18 (made by Kao Co., Ltd.) Polycarboxylic acid type polymer) "," Emulgen 920, 930, 931, 935, 950, 985 (polyoxyethylene nonylphenyl ether) "," acetamine 24 (coconut amine acetate), 86 (stearyl amine acetate) ";"Solspers 5000 (phthalocyanine ammonium salt type), 13240, 13940 (polyesteramine type), 17000 (fatty acid amine type), 24000, 32000" manufactured by Nikko Chemical Co., Ltd. "Nikkor T106 (polyoxyethylene sorbitan monooleate), MY" -IEX (polyoxyethylene monostearate), Hexagline4-0 (hexaglyceryl ruthenate Huwei rate) ", and the like.

These pigment dispersants are preferably contained in the ink in the range of 0.1 to 20% by mass. Moreover, it is also possible to use a synergist according to various pigments as a dispersion aid. These dispersants and dispersion aids are preferably added in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. The dispersion medium is used using a solvent or a polymerizable compound, but the ink of the present invention is preferably solvent-free because it is reacted and cured after printing. If the solvent remains in the cured image, the solvent resistance deteriorates and the VOC of the remaining solvent arises. Therefore, it is preferable in view of dispersibility that the dispersion medium is not a solvent but a polymerizable compound, and among them, a monomer having the lowest viscosity is selected.
The pigment is preferably dispersed so that the average particle size of the pigment particles is 0.08 to 0.5 μm, and the maximum particle size is 0.3 to 10 μm, preferably 0.3 to 3 μm. The selection of the dispersion medium, the dispersion conditions, and the filtration conditions are appropriately set. By controlling the particle size, clogging of the nozzles of the recording head can be suppressed, and ink storage stability, ink transparency, and curing sensitivity can be maintained.

In the ink of the present invention, a conventionally known dye, preferably an oil-soluble dye can be used as necessary. Specific examples of oil-soluble dyes that can be used in the present invention are given below, but the present invention is not limited to these.

(Magenta dye)
MS Magenta VP, MS Magenta HM-1450, MS Magenta HSo-147 (manufactured by Mitsui Toatsu Co., Ltd.), AIZENSOT Red-1, AIZEN SOT Red-2, AIZEN SOTRed-3, AIZEN SOT Pink-1, SPERON Red GE SPECIAL (above, manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN Red FB 200%, MACROLEX Red Violet R, MACROLEX ROT5B (above, manufactured by Bayer Japan), KAYASET Red B, KAYASET Red 130, KAYASET Red Japan 802 ), PHLOXIN, ROSE BENGAL, ACID Red (above, made by Daiwa Kasei), HSR-31, DIARESIN Red K (below) , Manufactured by Mitsubishi Kasei Co., Ltd.), Oil Red (manufactured by BASF Japan Co., Ltd.).

(Cyan dye)
MS Cyan HM-1238, MS Cyan HSo-16, Cyan HSo-144, MS Cyan VPG (manufactured by Mitsui Toatsu Co., Ltd.), AIZEN SOT Blue-4 (manufactured by Hodogaya Chemical Co., Ltd.), RESOLIN BR. Blue BGLN 200%, MACROLEX Blue RR, CERES Blue GN, SIRIUS SUPRATURQ. Blue Z-BGL, SIRIUS SUTRA TURQ. Blue FB-LL 330% (above, manufactured by Bayer Japan), KAYASET Blue
FR, KAYASET Blue N, KAYASET Blue 814, Turq. Blue GL-5 200, Light Blue BGL-5 200 (above, Nippon Kayaku Co., Ltd.), DAIWA Blue 7000, Oleosol Fast Blue GL (above, Daiwa Kasei), DIARESIN Blue P (Mitsubishi Kasei), SUDAN Blue 670, NEOPEN Blue 808, ZAPON Blue 806 (above, manufactured by BASF Japan).

(Yellow dye)
MS Yellow HSm-41, Yellow KX-7, Yellow EX-27 (Mitsui Toatsu), AIZEN SOT Yellow-1, AIZEN SOT YellowW-3, AIZEN SOT Yellow-6 (above, manufactured by Hodogaya Chemical Co., Ltd.), MACROLEX Yellow 6G, MACROLEX FLUOR. Yellow 10GN (above, Bayer Japan), KAYASET Yellow SF-G, KAYASET Yellow 2G, KAYASET Yellow AG, KAYASET Yellow EG (above, Nippon Kayaku), DAIWA Yellow 330H HSY-68 (manufactured by Mitsubishi Kasei Co., Ltd.), SUDAN Yellow 146, NEOPEN Yellow 075 (above, manufactured by BASF Japan).

(Black dye)
MS Black VPC (Mitsui Toatsu Co., Ltd.), AIZEN SOT Black-1, AIZEN SOT Black-5 (above, Hodogaya Chemical Co., Ltd.), RESORIN Black GSN 200%, RESOLIN Black BS (above, Bayer Japan Co., Ltd.), KAYASET Black A-N (manufactured by Nippon Kayaku Co., Ltd.), DAIWA Black MSC (manufactured by Daiwa Kasei Co., Ltd.), HSB-202 (manufactured by Mitsubishi Kasei Co., Ltd.), NEPTUNE Black X60, NEOPEN Black X58 (manufactured by BASF Japan) .

  The amount of pigment or oil-soluble dye added is preferably 0.1 to 20% by mass, more preferably 0.4 to 10% by mass. If it is 0.1% by mass or more, good image quality can be obtained, and if it is 20% by mass or less, an appropriate ink viscosity in ink ejection can be obtained. In addition, two or more kinds of colorants can be mixed as appropriate for color adjustment.

(Photopolymerization initiator)
In the ink of the present invention, when ultraviolet rays or the like are used as the active light, it is preferable to contain at least one photopolymerization initiator. However, in the case where an electron beam is used as the actinic ray, a photopolymerization initiator is not required in many cases.
Photopolymerization initiators can be broadly classified into two types: intramolecular bond cleavage type and intramolecular hydrogen abstraction type.
Examples of the intramolecular bond cleavage type photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2. -Hydroxy-2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2-morpholino (4 Acetophenones such as -thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone; benzoins such as benzoin, benzoin methyl ether, benzoin isopropyl ether; 2 , 4,6-Trimethylbenzoindiphenyl Scan fins oxides such acylphosphine oxide of benzil, methyl phenylglyoxylate esters.
On the other hand, as an intramolecular hydrogen abstraction type photopolymerization initiator, for example, benzophenone, methyl 4-phenylbenzophenone, o-benzoylbenzoate, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyl Benzophenones such as diphenyl sulfide, acrylated benzophenone, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 3,3'-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2 1,4-dimethylthioxanthone, 2,4-diethylthioxanthone, thioxanthone series such as 2,4-dichlorothioxanthone; Michler-ketone, aminobenzophenone series such as 4,4'-diethylaminobenzophenone; 10-butyl- - chloro acridone, 2-ethyl anthraquinone, 9,10-phenanthrenequinone, camphorquinone, and the like.

The amount of the photopolymerization initiator used is preferably in the range of 0.01 to 10% by mass of the actinic ray curable composition.
Examples of radical polymerization initiators include triazine derivatives described in JP-B-59-1281, JP-B-61-9621, JP-A-60-60104, JP-A-59-1504, and JP-A-59-1504. Organic peroxides described in JP-A-61-243807, JP-B-43-23684, JP-B-44-6413, JP-B-44-6413, JP-B-47-1604, etc., and the United States Diazonium compounds described in Japanese Patent No. 3,567,453, organic azides described in US Pat. Nos. 2,848,328, 2,852,379 and 2,940,853 Compounds, ortho-quinonediazides described in JP-B 36-22062, JP-B 37-13109, JP-B 38-18015, JP-B 45-9610 and the like, Various onium compounds described in JP-A-55-39162, JP-A-59-14023, and the like, and “Macromolecules, Vol. 10, page 1307 (1977); No. 142205, JP-A-1-54440, European Patent No. 109,851, European Patent No. 126,712, etc., “Journal of Imaging Science” (J. Imag. 61-151197, titanocenes, “Coordination Chemistry Levi (Coordination Chemistry Review), 84, 85-277 (1988) and JP-A-2-182701, transition metal complexes containing transition metals such as ruthenium, JP-A-3-209477 No. 2,4,5-triarylimidazole dimer, carbon tetrabromide, and organic halogen compounds described in JP-A-59-107344. These polymerization initiators are preferably contained in the range of 0.01 to 10 parts by mass with respect to 100 parts by mass of the compound having an ethylenically unsaturated bond capable of radical polymerization.
In the ink of the present invention, a photoacid generator can also be used as a photopolymerization initiator.

As the photoacid generator, for example, a chemically amplified photoresist or a compound used for photocationic polymerization is used (edited by Organic Electronics Materials Research Group, “Organic Materials for Imaging”, Bunshin Publishing (1993), 187. To page 192). Examples of compounds suitable for the present invention are listed below.
First, diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 -, CF 3 SO 3 - and salts be able to.
Specific examples of the onium compound that can be used in the present invention include compounds described in paragraph No. (0132) of JP-A No. 2005-255821.
Specific examples of the sulfonated compound that generates sulfonic acid include compounds described in paragraph No. (0136) of JP-A-2005-255821.
Secondly, halides that generate hydrogen halide can also be used, and specific examples thereof include compounds described in paragraph No. (0138) of JP-A No. 2005-255821. it can.
Thirdly, an iron allene complex described in paragraph No. (0140) of JP-A-2005-255821 can be mentioned.

(Other additives)
Various additives other than those described above can be used in the actinic ray curable ink according to the present invention. For example, surfactants, leveling additives, matting agents, polyester resins for adjusting film properties, polyurethane resins, vinyl resins, acrylic resins, rubber resins, and waxes can be added. In addition, any known basic compound can be used for the purpose of improving storage stability. Typical examples include basic organic compounds such as basic alkali metal compounds, basic alkaline earth metal compounds, and amines. Etc.

Hereinafter, specific examples of the ink used in the present embodiment will be listed.
In addition, the pigment dispersion used in the following ink composition comprises 5 parts of Solspers 32000 (manufactured by Lubrizol) and 80 parts of HD-N (1,6-hexanediol dimethacrylate: Shin-Nakamura Chemical Co., Ltd.). After stirring and dissolving in a stainless steel beaker and cooling to room temperature, 15 parts of carbon black (# 56: manufactured by Mitsubishi Chemical Corporation) is added, sealed in a glass bottle with 0.5 mm zirconia beads, and put into a paint shaker. Then, after the dispersion treatment for 10 hours, the zirconia beads were removed.

Next, the operation of this embodiment will be described.
First, before image formation, the operator inputs the type of recording medium P on which image formation is to be performed to the recording medium type input unit 16. The control unit 10 determines the heating temperature corresponding to the type of the recording medium P based on the content input to the recording medium type input unit 16. And the control part 10 heats the 1st heat roller 7 and the 2nd heat roller 8 so that it may become the said heating temperature. At this time, the control unit 10 monitors the surface temperature of the image forming drum 21 and the surface temperature of the first heat roller 7 based on the detection results of the drum temperature sensor 9 and the roller temperature sensor 17, and the detection result Is fed back to the heating temperature of the first heat roller 7 and the second heat roller 8, so that the target temperature is always controlled.
The reason why the heating temperature is determined corresponding to the type of medium (including those of the same type but different in thickness) is that the gel temperature of the ink and the recording medium P are originally determined by the first heat roller 7 as described above. This is because the drum temperature sensor 9 and the roller temperature sensor 17 do not directly detect the temperature of the recording medium P as described above.

Thereafter, when image formation is started, the control unit 10 controls each of the units by controlling the sheet feeding unit driving source 13, the transfer drum driving source 11, the image forming drum driving source 12, and the stacking unit driving source 14.
Specifically, when the recording medium P is transported from the paper feed tray 31 to the transfer drum 22 by the paper feed transport unit 32, the recording medium P is attracted to the outer peripheral surface of the transfer drum 22 by the suction unit.
When the recording medium P comes close to the image forming drum 21 by the rotation of the transfer drum 22, the leading end of the recording medium P is held by the claw portion 211, and the entire recording medium P is sucked by the suction pump 215. It is adsorbed on the outer peripheral surface of.

  Before the recording medium P is attracted to the image forming drum 21, the image forming drum 21 is heated by the second heat roller 8 on the upstream side thereof, so that the recording medium P is also preheated. Thereafter, when the recording medium P comes into contact with the first heat roller 7 as the image forming drum 21 rotates, the first heat roller 7 further heats the recording medium P. Thereby, the recording medium P is heated to a temperature corresponding to the type.

Then, when the recording medium P faces the recording head 5 as the image forming drum 21 rotates, the control unit 10 controls the recording head driver 15 to eject ink from each recording head 5, and on the recording medium P. An image is formed on.
After the image formation, when the recording medium P faces the energy beam irradiation unit 6 as the image forming drum 21 rotates, the control unit 10 controls the energy beam irradiation unit 6 to irradiate the recording medium P with the energy beam. . As a result, each ink is cured and the image is fixed on the recording medium P.

  Thereafter, when the recording medium P comes close to the accumulation transport belt 424, the recording medium P is transported by the accumulation transport belt 424 and stored in the storage tray 41. Thus, a series of image forming operations is completed.

  As described above, according to the present embodiment, the first heat roller 7 that heats the image forming drum 21 from the front side is provided between the transfer drum 22 and the recording head 5. The medium P can be heated. If the temperature of the recording medium P before ink landing can be controlled, the recording medium P can be preheated to a temperature at which gloss is stabilized. Therefore, even when an ink that changes phase between gel (or solid) and liquid is used depending on the temperature, the gloss of the formed image can be stabilized.

Moreover, since the control part is controlling the 1st heat roller 7 based on the detection result of the drum temperature sensor 9 or the roller temperature sensor 17, feedback control becomes possible and it can heat to the target temperature accurately. it can.
Further, since the second heat roller 8 is also provided on the upstream side in the rotation direction of the image forming drum 21, it is possible to heat the image forming drum 21 in advance before the recording medium P contacts the image forming drum 21. it can. As a result, the temperature due to the difference in thickness of the recording medium P can be compensated, and finer gloss control is possible.

Since the heating temperature of at least one of the first heat roller 7 and the second heat roller 8 is controlled based on the type of the recording medium P input to the recording medium type input unit 16, the type of the recording medium P Each can be heated at an optimum heating temperature, and gloss control according to the type of the recording medium P becomes possible.
The input of the type of the recording medium P can be input by an operator, but is performed by a sensor for identifying the type of the recording medium P installed on the upstream side of the first heat roller 71 and in the passage path of the recording medium P. May be. This sensor is not limited in type, and any sensor may be used as long as the type of the recording medium P can be identified.
Further, instead of inputting the type of the recording medium P by the operator, the type information may be read by a reader from a barcode attached to a case or the like in which the recording medium P is stored.

  Further, the first heating means and the second heating means are made of a rotatable pipe-shaped first heat roller 7 and second heat roller 8 having elastic bodies 72 and 82 coated on the outer periphery and heat sources 73 and 83 on the inner side. Therefore, the elastic bodies 72 and 82 are elastically deformed so that the contact area with the image forming drum 21 can be increased, and the image forming drum 21 and the recording medium P can be efficiently heated.

The image forming drum 21 has a claw portion 211 that sandwiches one end of the recording medium P, and a plurality of suction holes 212 that attract the recording medium P to the outer peripheral surface of the image forming drum 21 by sucking the recording medium P. Therefore, the flatness of the recording medium P can be ensured even if the recording medium P has a different size.
Further, since the plurality of suction holes 212 are arranged in a pattern having a blue noise characteristic, even if traces of the suction holes 212 remain on the recording medium P after the image formation, the irregular patterns visually Can be difficult to recognize.
Since the suction hole 212 is provided only in the region P3 overlapping the portion P2 deviated from the image forming region P1 of the recording medium P, it is possible to prevent the suction hole 212 from remaining in the image forming region P1.

Note that the present invention is not limited to the above embodiment, and can be modified as appropriate. In the following description, the same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof is omitted.
For example, in the above-described embodiment, the delivery drum 22 is exemplified as the supply unit that delivers the recording medium P to the image forming drum 21. However, the supply unit may be an arm type or a belt type. It is done. If the supply means is a drum type (delivery drum 22), a heat source can be provided inside the delivery drum 22 to also serve as the function of the first heat roller 7.

  Further, the rotation speed of the first heat roller 7 is preferably set to be equal to or lower than the rotation speed of the image forming drum 21. With such a rotational speed, it is possible to prevent the recording medium P from being wrinkled when the recording medium P is sandwiched and conveyed between the first heat roller 7 and the image forming drum 21.

Moreover, although the case where the first heating unit and the second heating unit are the heat rollers 7 and 8 has been described in the above embodiment, an endless belt type heating unit may be used. FIG. 6 is a schematic view showing an example of an endless belt type heating means. As shown in FIG. 6, the endless belt type heating means 50 includes three driving rollers 51 disposed around the image forming drum 21 and an endless belt 52 stretched around the three driving rollers 51. ing. The endless belt 52 is a thin metal belt, and an elastic body is coated on the outer periphery thereof. A part of the outer peripheral surface of the endless belt 52 is in contact with the surface of the image forming drum 21. Inside the endless belt 52, a heater 53 is provided as a heat source. Thus, the endless belt type heating means 50 can increase the contact area with the image forming drum 21 and enable efficient heating.

(Example)
Here, a more detailed and preferable embodiment of the image forming drum 21 will be described below. FIG. 7 is a cross-sectional view showing a cross section perpendicular to the rotation center line of the image forming drum 21. As shown in the figure, the image forming drum 21 has a support body 21a made of a rigid body that is a cylindrical skeleton at the center thereof, a heat insulating layer 21b formed on the outer peripheral surface of the support body 21a, and an outer side of the heat insulating layer 21b. It has the structure provided with the heat storage layer 21c formed in this.
The support 21a is made of SUS304 (stainless steel), the heat insulating layer 21b has a thickness of 2 [mm], and the material is epoxy.

  As described above, the image forming drum 21 is configured to be heated from the outside by the first heat roller 7 and the second heat roller 8, and can be used after the main power of the inkjet recording apparatus 1 is turned on ( Here, the target temperature of the image forming drum 21 is set to 45 ± 3 degrees), and it is necessary to quickly raise the temperature. Generally, 300 [sec] is allowed to be usable after the main power is turned on.

As a parameter for determining the time required for raising the temperature of the image forming drum 21, the heat capacity per unit area on the surface occupies a large weight.
FIG. 8 shows the heat storage layer 21c of the image forming drum 21 whose thickness is 1,2,3,4,5 [mm] and whose heat capacity per unit area is adjusted to 30 ° C. ( It is the graph which showed the result which measured the time required to heat up from 45 degreeC (setting temperature required at the time of image formation) to 45 degreeC (presumed general environmental temperature).
In addition, in FIG. 8, it has each illustrated about the case where the raw material of the thermal storage layer 21c is made from SUS304 (* mark) and aluminum (Δ mark). The vertical axis represents the heat capacity per unit area of the heat storage layer 21c of each image forming drum 21 used for the measurement (unit: [J / (m ² · K)]), and the horizontal axis represents the required time to the target temperature (unit: [s]).
According to this comparative test, the heat storage layer 21c showed a result in which the required heating time was proportional to the heat capacity per unit area for any material. According to the approximate line indicating the relationship between the required heating time and the heat capacity per unit area, in order to make the required time 300 [s] or less, the heat capacity per unit area is 9000 [J / (m ² · K )] Was required.
Therefore, it can be said that the heat storage layer 21c preferably has a heat capacity per unit area of 9000 [J / (m ² · K)] or less from the viewpoint of speeding up the temperature rise to the target temperature. In addition, about the raw material of the thermal storage layer 21c, although SUS304 and aluminum are preferable, it does not show that it should restrict to SUS304 and aluminum especially.

If the heat capacity per unit area of the heat storage layer 21c of the image forming drum 21 is too small, the temperature is likely to decrease when the recording medium P is supplied to the image forming drum 21.
For the image forming drum 21 heated to 48 ° C., which is the upper limit of the set temperature, the thickest 600 [μm] recording medium P expected to be used (the thickest recording medium P is the temperature of the image forming drum 21). Of the heat storage layer 21c required for maintaining the lower limit of 42 ° C., which is the lower limit of the temperature allowed for image formation, when the temperature is 25 ° C. (normal temperature of the recording medium P). The heat capacity per unit area is 2890 [J / (m ² · K)] according to theoretical calculations. If the heat storage layer 21c has a heat capacity per unit area smaller than this, high image quality cannot be maintained for the thick recording medium P. Therefore, it is desirable that the heat capacity per unit area of the heat storage layer 21c of the image forming drum 21 is 3000 [J / (m ² · K)] or more in consideration of changes in environmental temperature.
That is, the heat capacity per unit area of the heat storage layer 21c of the image forming drum 21 is 3000 [J / (m ² · K)] from the viewpoints of both the time required for temperature increase and the temperature decrease when the recording medium P is supplied. A range of 9000 [J / (m ² · K)] or less is desirable.

Further, the heat storage layer 21c of the image forming drum 21 needs to quickly transmit heat to the recording medium P supplied from the image forming drum 21 to raise the temperature of the recording medium P. For this reason, the heat storage layer The thermal conductivity of 21c is preferably 15 [W / (m · K)] or more. If it is less than this, heat transfer from the image forming drum 21 to the recording medium P will not be performed well, which will affect the stabilization of image quality.
FIG. 9 shows the materials of the heat storage layer 21c of the image forming drum 21 made of SUS304 (thermal conductivity 17 [W / (m · K)]), aluminum (thermal conductivity 235 [W / (m · K)]), nickel steel. 30Ni (thermal conductivity 12 [W / (m · K)]) Nickel steel 40Ni (thermal conductivity 10 [W / (m · K)]) Is a graph showing the results of measuring the time required to raise the temperature from 25 ° C. (normal temperature of the recording medium P) to 42 ° C. (lower limit of temperature allowed for image formation).
The vertical axis represents the thermal conductivity (unit: [W / (m · K)]) of the heat storage layer 21c of each image forming drum 21 used for the measurement, and the horizontal axis represents the time required for the target temperature (unit: [s]). ).
Like aluminum, even if the thermal conductivity of the heat storage layer 21c is much higher than 15 [W / (m · K)], the time required for raising the temperature of the recording medium P is not greatly shortened.
The heat transfer coefficient when the recording medium P is paper is 2.83 [W / (m · K)]. It is desirable that the ratio of the heat transfer coefficient of the heat storage layer 21c and the heat transfer coefficient of the recording medium P is 5 or more by 15 ÷ 2.83≈5. Moreover, since the heat insulation effect is acquired when the heat insulation layer 21b is thicker, the thickness is more preferably 2 [mm] or more as described above.

The heat insulating layer 21b of the image forming drum 21 preferably has a thermal conductivity of O.20 [W / (m · K)] or less. By setting the thermal conductivity of the heat insulating layer 21b of the image forming drum 21 to O.20 [W / (m · K)] or less, heat transfer from the heat storage layer 21c to the support 21a is suppressed, and the heat storage layer 21c is The temperature can always be maintained at a predetermined temperature, and the image quality of the formed image can be maintained high. Moreover, power saving of each heat roller can be achieved.
Furthermore, it is desirable that the thickness of the silent layer 21b be 100 [μm] or more. Also in this case, heat transfer from the heat storage layer 21c to the support 21a is suppressed, and it is possible to obtain the effect of maintaining high image quality and saving power. Moreover, since the heat insulation effect is acquired when the heat insulation layer 21b is thicker, the thickness is more preferably 2 [mm] or more as described above.

  As described above, the desirable configuration of the image forming drum 21 shown in the above-described embodiment is the recording medium P that is supplied by storing the image forming drum 21 in advance and storing it in advance, as in the inkjet recording apparatus 1. In the case of the configuration in which the temperature of the recording medium is increased, it is particularly effective and preferable for speeding up the temperature of the image forming drum, effectively increasing the temperature of the recording medium P, and stabilizing the image quality associated therewith. it can.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Image formation part 3 Paper feed part 4 Accumulation part 5 Recording head 7 1st heat roller (1st heating means)
8 Second heat roller (second heating means)
DESCRIPTION OF SYMBOLS 9 Drum temperature sensor 10 Control part 17 Roller temperature sensor 19 Image creation apparatus 21 Image formation drum 22 Delivery drum (supply means)
P Recording medium

Claims (8)

An ink jet recording apparatus using an ink containing a gelling agent and phase-changing between a gel state and a liquid state depending on temperature,
An image forming drum that holds the recording medium on the outer peripheral surface and conveys the recording medium while rotating;
A plurality of recording heads for forming an image by ejecting the ink onto the recording medium held on said image forming drum,
Supply means for delivering the recording medium to the image forming drum;
The image forming drum is arranged at the downstream side of the delivery position of the recording medium by the supply unit and the upstream side of the recording head in the rotation direction of the image forming drum at the time of image formation , and the outer peripheral surface side of the image forming drum is arranged from the outside of the image forming drum. A first heating means for heating and heating the image forming drum and the recording medium before image formation held on the image forming drum ;
The image forming drum is
A heat storage layer that forms the outermost peripheral layer of the outer peripheral surface and has a heat capacity per unit surface area of 3000 [J / (m ² · K)] or more and 9000 [J / (m ² · K)] or less ,
A heat insulating layer located on the lower layer side of the heat storage layer; and
An ink jet recording apparatus having a structure including the heat storage layer and a support that supports the heat insulating layer. A temperature sensor for detecting at least one of a surface temperature of the image forming drum and a temperature of the first heating unit;
A control unit that controls the first heating unit based on a detection result of the temperature sensor so that a temperature difference between the temperature of the recording medium at the time of image formation and the gelation temperature of the ink is within a predetermined range; The inkjet recording apparatus according to claim 1. An image forming drum is disposed upstream of the recording medium delivery position by the supply unit and downstream of the recording medium discharge position after image formation in the rotational direction of the image forming drum during image formation. 3. An ink jet recording apparatus according to claim 1, further comprising a second heating means for heating the outer peripheral surface side of the ink jet recording apparatus. The ink is an actinic ray curable ink that is cured by irradiation with energy rays,
In the rotational direction of the image forming drum at the time of image formation, an energy beam is disposed on the upstream side of the discharge position of the recording medium after image formation and on the downstream side of the recording head, and is applied to the recording medium on the image forming drum. An ink jet recording apparatus according to any one of claims 1 to 3, further comprising an energy beam irradiation unit that irradiates .   5. The ink jet recording apparatus according to claim 1, wherein the heat storage layer has a thermal conductivity of 15 [W / (m · K)] or more.   The ink jet recording apparatus according to claim 1, wherein the heat storage layer is formed of stainless steel or aluminum.   The inkjet recording apparatus according to any one of claims 1 to 6, wherein the heat conductivity of the heat insulating layer is set to O.20 [W / (m · K)] or less.   The inkjet recording apparatus according to any one of claims 1 to 7, wherein the thickness of the silent layer is 100 [μm] or more.

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