JP2013230643A - Inkjet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an inkjet recording apparatus in which maintenance of a head part is easily performed.SOLUTION: Maintenance of an ink discharge part 51 (head part 51a) is made easy by enabling workers to approach from both sides of the ink discharge part 51 moved to a maintenance position R2 by enabling arbitrary ink discharge parts 51 of a plurality of ink discharge parts 51 of an inkjet recording apparatus 1 to move individually to the maintenance position R2 in a separating direction from an imaging drum 21, and by entry of each worker in an exterior part 20 from a door 20a and a door 20b.

Description

  The present invention relates to an inkjet recording apparatus that records an image by ejecting ink onto a recording medium.

Conventionally, an image forming drum that holds and conveys a recording medium on the outer peripheral surface thereof, and is arranged in the recording medium conveyance direction along the outer peripheral surface of the image forming drum, and ink is applied to the recording medium conveyed by the image forming drum. 2. Related Art An ink jet recording apparatus having a plurality of head units that form an image by ejecting ink is known.
For example, the ink jet recording apparatus includes four head portions that eject inks of four colors, cyan (C), black (K), magenta (M), and yellow (Y). During maintenance, these four head parts are moved together in the transport direction or in the direction opposite to the transport direction so that the four head parts are separated from the image forming drum, and each head part is cleaned and parts are moved. It is possible to perform a replacement work of the above (see, for example, Patent Document 1).

JP 2011-131435 A

  However, in the case of the above-mentioned Patent Document 1, among the four head portions, the head portion arranged close to the working position can be easily maintained, but each head portion has a plurality of recording heads that eject ink. Since they are arranged in a row, it may be difficult to reach the recording head near the image forming drum, which is far from the work position, and maintenance such as replacement or repair of the recording head itself or its components becomes difficult. There was a problem that there was something.

  An object of the present invention is to provide an ink jet recording apparatus excellent in maintainability of a recording head.

In order to solve the above problems, the invention described in claim 1
An inkjet recording apparatus that records on a recording medium by discharging ink,
An image forming drum that holds and conveys the recording medium on its outer peripheral surface;
A plurality of head portions that form an image by ejecting the ink onto the recording medium that is arranged in the conveyance direction of the recording medium and conveyed by the image forming drum;
A carriage that supports the plurality of head portions so as to be individually movable at a print position for forming an image and a maintenance position that is separated from the image forming drum in a direction that intersects the transport direction;
An exterior portion that houses the image forming drum, the plurality of head portions, and the carriage;
The exterior portion is provided with at least two door portions that allow entry into two places sandwiching the head portion moved to the maintenance position.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The head section includes a plurality of recording heads that eject the ink, and the plurality of recording heads are arranged in a plurality of rows along a direction that intersects the transport direction. To do.

The invention according to claim 3 is the ink jet recording apparatus according to claim 1 or 2,
The ink is an energy ray curable ink.

  According to the present invention, it is possible to facilitate maintenance of the head portion of the ink jet recording apparatus.

It is a schematic diagram which shows the internal structure of the inkjet recording device of this invention. It is a schematic diagram which shows the internal structure of an image formation part. It is a perspective view which shows schematic structure of an image forming drum. FIG. 4 is a cross-sectional view illustrating a schematic configuration of the image forming drum in FIG. 3, which is a cross-sectional view as viewed from a IV-IV cut surface in FIG. 5. FIG. 5 is a cross-sectional view showing a schematic configuration of the image forming drum in FIG. 3, and is a cross-sectional view seen from a VV cut surface in FIG. 4. It is sectional drawing which shows schematic structure of a heating roller. It is a perspective view which shows schematic structure of an ink discharge part. FIG. 2 is a front view illustrating a schematic configuration of an ink discharge unit. FIG. 4 is a bottom view illustrating a schematic configuration of an ink discharge unit. It is a perspective view which shows schematic structure of an exterior part. It is a perspective view which shows the state which opened the door part and window part of the exterior part. FIG. 4 is an explanatory diagram illustrating an arrangement of an image forming drum and an ink discharge unit that are arranged inside an exterior part. It is explanatory drawing which shows the printing position and the maintenance position in the inside of an exterior part. It is explanatory drawing regarding the standing position of the worker who performs a maintenance operation | work inside an exterior part. It is a block diagram which shows the control system of an inkjet recording device.

  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.

(overall structure)
FIG. 1 is a schematic diagram showing an internal configuration of an ink jet recording apparatus as an image forming apparatus according to a first 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 accumulation unit 4 for accumulating P.

(Paper Feeder)
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.

(Accumulator)
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.

(Image forming part)
FIG. 2 is a schematic diagram illustrating an internal configuration of the image forming unit 2. As shown in FIG. 2, the image forming unit 2 includes an image forming drum 21 that holds the recording medium P on the surface and a recording medium P conveyed from the paper feeding unit 3 in order to form an image on the recording medium P. And a transfer drum 22 as a recording medium supply means for transferring the image to the image forming drum 21.

  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. FIG. 4 is a cross-sectional view showing a schematic configuration of the image forming drum 21, and is a cross-sectional view seen from the IV-IV cut surface in FIG. FIG. 5 is a cross-sectional view showing a schematic configuration of the image forming drum 21, and is a cross-sectional view seen from the VV cut surface of FIG. The image forming drum 21 is an inkjet image forming drum according to the present invention. As shown in FIGS. 3 to 5, the image forming drum 21 includes a cylindrical main body 215 having a hollow interior, and a main body 215. And a pair of support portions 216 and 217 that support both end portions of the main body portion 215 are provided.

Around the main body 215, a plurality of claw portions 211 that sandwich one end of the recording medium P are provided to hold the recording medium P on the outer peripheral surface of the main body 215. A plurality of claw portions 211 are accommodated in the recess 213 formed on the outer peripheral surface of the main body portion 215 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.
In addition, a plurality of suction holes 212 for closely attaching the recording medium P to the outer peripheral surface of the main body 215 are formed around the main body 215.

  The pair of support portions 216 and 217 are in close contact with the entire circumference of the main body portion 215. Of the pair of support portions 216 and 217, one support portion 216 is formed with a communication port 241 that communicates with the inside of the hollow portion 2219 of the main body portion 215. For example, a suction pump (not shown) is connected to the communication port 241, and the hollow portion 219 of the image forming drum 21 becomes negative pressure by the suction pump. When the hollow part 219 becomes negative pressure, the recording medium P is adsorbed on the outer peripheral surface of the main body part 215 through the suction hole 212.

  Further, since the plurality of suction holes of the suction portion 212 are arranged in a pattern having a blue noise characteristic, even if the traces of the suction holes remain on the recording medium P after the image formation, the irregular pattern This makes it difficult to visually recognize. In addition, since the suction holes are provided only in the area outside the image forming area of the recording medium P, it is possible to prevent the trace of the suction holes from remaining in the image forming area.

  The image forming unit 2 uses an ink (details will be described later) that cause a phase change from a gel to a liquid according to the temperature. The temperature is adjusted by heating the recording medium P during image formation. Controls the smoothness and gloss of ink dots. Therefore, it is assumed that the image forming drum 21 is heated. Therefore, the outer peripheral surface of the image forming drum 21 has a multilayer structure in which a heat storage layer is formed on a heat insulating layer.

As shown in FIG. 2, the image forming unit 2 includes a plurality of ink discharge units 51, a UV lamp 52, a drum temperature sensor 91, heating rollers 71 and 72, and a cooling fan 53 around the image forming drum 21. Has been placed. The image forming drum 21, the ink discharge unit 51, and the like are accommodated in an exterior unit 20 described later.
The ink ejection unit 51 includes a head unit 51a that ejects ink and a carriage 51b that holds the head unit 51a (details will be described later).
A plurality of ink discharge portions 51 (head portions 51a) are arranged along the circumferential direction of the image forming drum 21 and aligned in the conveyance direction of the recording medium P. The head part 51 a of each ink discharge part 51 is a line type recording head part extending 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 ink ejection units 51 are provided so that four colors of ink of black (K), yellow (Y), magenta (M), and cyan (C) can be ejected. Although provided, the number may be increased or decreased according to the number of necessary colors.

  The ink ejected from the head part 51a of the ink ejection part 51 is an ink that changes in phase from gel or solid to liquid according to temperature and has a phase transition point at 40 ° C. or higher and lower than 100 ° C. The ink ejected from the plurality of ink ejection sections 51 is set to have a higher phase transition temperature for ink ejected upstream in the transport direction Y than for ink ejected downstream in the transport direction Y. ing. Specifically, in order from the upstream side, the first ink discharge portion 51A, the second ink discharge portion 51B, the third ink discharge portion 51C, and the fourth ink discharge portion 51D, and the ink discharged from the first ink discharge portion 51A. The phase transition temperature is P1, the phase transition temperature of the ink ejected from the second ink ejection unit 51B is P2, the phase transition temperature of the ink ejected from the third ink ejection unit 51C is P3, and the ejection is performed from the fourth ink ejection unit 51D. Assuming that the phase transition temperature of the ink is P4, the relationship is P1> P2> P3> P4.

  The phase transition temperature of the ink can be adjusted by changing the type of gelling agent added to the ink, the amount of gelling agent added, and the type of actinic ray curable monomer. By this adjustment, as described above, the phase transition temperature of the ink ejected on the upstream side in the transport direction Y is set higher than that of the ink ejected on the downstream side in the transport direction Y. Specifically, among the plurality of ink discharge portions 51 (head portions 51a), the phase transition temperature difference of the ink discharged by the pair of ink discharge portions 51 adjacent along the transport direction Y is 0.5 ° C. or more. The phase transition temperature of the ink ejected by each ink ejection section 51 is adjusted so that it falls within the range of 10 ° C. or lower, preferably within the range of 1 ° C. or higher and 5 ° C. or lower. Details of the ink will be described later.

  As shown in FIG. 2, a UV (ultraviolet) lamp 52 as an energy ray irradiating means for irradiating energy rays such as ultraviolet rays, for example, is disposed immediately downstream in the transport direction Y of the recording medium P in the plurality of ink ejection portions 51. Has been. The UV lamp 52 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.

Immediately downstream of the UV lamp 52 in the transport direction Y, the stacking transport roller 421 of the stacking transport unit 42 is disposed. Further, a part of the outer periphery of the stacking transport roller 421 is close to the image forming drum 21 via the stacking transport belt 424, and the recording medium P is transported from the image forming drum 21 at this close portion. It is to be delivered to 424.
Further, a cooling fan 53 that cools the outer peripheral surface of the image forming drum 21 by blowing air is provided immediately downstream of the stacking conveyance roller 421.

  A heating roller 72 of the second heating unit is provided immediately downstream of the cooling fan 53, and a drum temperature sensor as a drum temperature detecting unit that measures the surface temperature of the image forming drum 21 is further downstream of the cooling roller 53. 91 is arranged. The drum temperature sensor 91 may use a contact-type temperature detection element such as a thermocouple or a thermistor, but a non-contact type temperature detection element such as a thermopile is more preferable.

  The heating roller 71 (heating body) of the first heating unit that heats the recording medium P before recording by the ink discharge unit 51 held on the image forming drum 21 is immediately downstream in the transport direction Y of the transfer drum 22, that is, It is arranged between the transfer drum 22 and the ink discharge part 51. A part of the heating roller 71 is in contact with the outer peripheral surface of the image forming drum 21, and the recording medium P is interposed between the heating roller 71 and the image forming drum 21 during image formation. At this time, the heating roller 71 presses the recording medium P against the outer peripheral surface of the image forming drum 21 to bring it into close contact therewith.

FIG. 6 is a cross-sectional view illustrating a schematic configuration of the heating roller 71. As shown in FIG. 6, the heating roller 71 is incorporated in a hollow pipe 711 made of a metal such as aluminum, an elastic layer 712 made of, for example, silicon rubber covering the entire circumference of the hollow pipe 711, and the hollow pipe 711. And a heating source 713 such as a halogen heater for heating the hollow pipe 711 and the elastic layer 712.
The elastic layer 712 is preferably made of a material having excellent thermal conductivity. Furthermore, the surface of the elastic layer 712 can be coated with a material having good slipperiness (for example, a PFA tube) to enhance durability.

  In the inkjet recording apparatus 1, a heating unit temperature sensor 92 that detects the temperature of the heating roller 71 of the first heating unit is provided in the heating roller 71. The heating unit temperature sensor 92 may use a contact-type temperature detection element such as a thermocouple or a thermistor similarly to the drum temperature sensor 91, but a non-contact type temperature detection element such as a thermopile is more preferable. .

  Further, in the periphery of the image forming drum 21, the first is provided on the downstream side of the accumulation transport roller 421 and upstream of the transfer drum 22 (more strictly, between the cooling fan 53 and the drum temperature sensor 91). The heating roller 72 (heating body) of the second heating unit has the same structure as the heating roller 71 of the first heating unit.

(Specific configuration of the ink discharge portion and the exterior portion)
FIG. 7 is a perspective view illustrating a configuration of the ink discharge unit 51. FIG. 8 is a front view of the ink discharge unit 51, and FIG. 9 is a bottom view of the ink discharge unit 51.
As shown in FIGS. 7 to 9, the ink discharge section 51 includes a head section 51a and a carriage 51b that holds the head section 51a.

The head unit 51a includes a plurality of recording heads 510 that eject ink, a head fixing plate 511 provided with the plurality of recording heads 510, an ink tank 512 that stores ink to be supplied to each recording head 510, and an ink tank. 512 and a flow path 513 for supplying ink to each recording head 510.
The head fixing plate 511 of the head portion 51 a has a length that extends over the entire length of the image forming drum 21, and the plurality of recording heads 510 intersect with the conveyance direction of the recording medium P by the image forming drum 21 (for example, Are arranged on the head fixing plate 511 so as to form a plurality of rows along a direction perpendicular to the conveying direction. In the present embodiment, eight recording heads 510 are arranged in four two rows per row so as to form a staggered arrangement. Each recording head 510 is attached so that ink can be discharged from the lower surface side of the head fixing plate 511 toward the outer peripheral surface of the image forming drum 21 so that the ink discharge surface is exposed on the lower surface of the head fixing plate 511. ing.

Each of the carriages 51a to 51d (explained only by the carriage 51b in the figure) has a pair of arm portions 515 that hold the both ends of the head fixing plate 511 and two connection plates 516 that connect the pair of arm portions 515, respectively. It has.
The carriages 51a to 51d are connected to a rail (not shown) that extends in a direction (for example, a direction orthogonal) intersecting the conveyance direction of the recording medium P. Each of the carriages 51a to 51d is arranged so as to be individually movable along the rail in a direction intersecting the conveyance direction of the recording medium P, and the head portion 51a held by the carriage 51b intersects the conveyance direction. It can be moved in the direction to do. That is, the carriages 51a to 51d are configured so that the head portions 51a to 51d mounted on each carriage can be moved individually.

  As will be described later, the ink ejection unit 51 includes a print position that forms an image facing the image forming drum 21, and a maintenance position that is separated from the image forming drum 21 in a direction that intersects the conveyance direction of the recording medium P. Can be moved to.

  FIG. 10 is a perspective view illustrating a schematic configuration of the exterior unit 20 in the image forming unit 2. FIG. 11 is a perspective view showing a state in which the door portion 20a (20b) and the window portion 20c of the exterior portion 20 are opened. FIG. 12 is an explanatory diagram showing the arrangement of the image forming drum 21 and the ink discharge unit 51 arranged inside the exterior unit 20. FIG. 13 is an explanatory diagram showing a print position R1 and a maintenance position R2 inside the exterior portion 20. As shown in FIG.

The image forming unit 2 includes an exterior unit 20 that accommodates an image forming drum 21, a plurality of ink discharge units 51 (a head unit 51a and a carriage 51b), and the like.
The exterior portion 20 is provided with an ink ejection portion for preventing the UV curable ink from being exposed to natural light until the UV curable ink is cured by the UV lamp 52, and particularly for accommodating the head portion 51a of the ink ejection portion 51 in the light shielding space. 51 is covered. The exterior portion 20 is provided with a rotation shaft of the image forming drum 21 so that the minimum necessary portions for maintenance of the plurality of ink discharge portions 51 (head portion 51a and carriage 51b) in the image forming portion 2 can be opened and closed. Door portions 20a and 20b are formed on each of two exterior wall surfaces formed in a substantially parallel direction, and a window portion 20c is provided on the exterior wall surface formed in a direction orthogonal to the rotation axis of the image forming drum 21. It has been.

The door portions 20a and 20b are doors that can be opened to allow an operator to enter the exterior portion 20 during maintenance. The window part 20c is a door that can be opened when the state inside the exterior part 20 is confirmed.
One door portion 20 a is provided on the wall surface of the exterior portion 20 on the upstream side of the rotation axis of the image forming drum 21 in the conveyance direction of the recording medium P. The other door portion 20 b is provided on the wall surface of the exterior portion 20 on the downstream side in the transport direction of the recording medium P with respect to the rotation shaft of the image forming drum 21. The window portion 20 c is provided on the wall surface of the exterior portion 20 that is close to the side of the image forming drum 21.
It is preferable that the exterior part 20 is mainly formed of a metal material that does not transmit natural light as a whole including the door parts 20a and 20b and the window part 20c. However, for the window portion 20c, an acrylic plate that has been subjected to UV cut processing may be used so that the inside state can be confirmed without opening the window portion 20c.

In the exterior portion 20, the image forming drum 21 is sandwiched between a pair of highly rigid side plates 210 and is rotatably supported.
In addition, a maintenance rod 200 is provided on the side of the image forming drum 21 in the exterior portion 20 and at a position outside the conveyance path of the recording medium P. The maintenance tub 200 has a function of preventing replacement parts from dropping during maintenance of the ink discharge section 51 and a function of a tray for ink discharged under pressure to remove foreign matter and bubbles in the recording head 510.

A plurality of ink ejection portions 51 that are supported so as to be movable in a direction intersecting the conveyance direction of the recording medium P are disposed at a print position R1 that faces the image forming drum 21 during image formation.
On the other hand, at the time of maintenance, the plurality of ink discharge portions 51 are individually moved to a maintenance position R2 located in the direction away from the image forming drum 21 and above the maintenance rod 200.

  At the time of the maintenance, as the worker enters the exterior portion 20 from the door portion 20a and the door portion 20b, the ink discharge portion 51 (head portion 51a) moved to the maintenance position R2 as shown in FIG. An operator can enter two places between the two sides, and the operator can perform maintenance work from both sides of the ink discharge unit 51.

As described above, an arbitrary ink discharge portion 51 among the plurality of ink discharge portions 51 can be individually moved to the maintenance position R2 in a direction away from the image forming drum 21, and from the door portion 20a and the door portion 20b. Each worker enters the exterior portion 20 so that the worker can approach from both sides of the ink discharge portion 51 moved to the maintenance position R2, so that the ink discharge portion 51 (head portion 51a) is maintained. It is easy.
In particular, since a predetermined maintenance operation can be performed with two workers sandwiching one ink discharge portion 51 moved to the maintenance position R2 from both sides, a plurality of recordings are recorded on the head portion 51a of the ink discharge portion 51. Even if the heads 510 are arranged in two rows, the operator can easily see each recording head 510 and can easily clean and replace the recording head 510.
In the above embodiment, the description has been given in the form in which one door portion is provided on each of the two exterior wall surfaces substantially parallel to the rotation axis direction of the drum 21, but in the configuration in which two or more door portions are provided on each wall surface. There may be. Further, the position of the door part is not particularly limited as long as it is the above-mentioned two exterior wall surfaces, but considering maintenance, a configuration in which the maintenance position R2 is disposed between the door parts of each wall surface is more preferable. .
Moreover, although the door part in the said embodiment has shown with the door-shaped thing, the structure which forms sufficient opening for an operator to perform a maintenance operation | work at the time of a maintenance, and shields the said opening at times other than a maintenance time If it is, it will not be specifically limited to a door-shaped thing, What kind of opening-and-closing means, such as a shutter-like opening-and-closing part, is included.

(Main control configuration of inkjet recording apparatus)
FIG. 15 is a block diagram showing a main control configuration of the inkjet recording apparatus 1. As shown in FIG. 15, the control unit 10 of the inkjet recording apparatus 1 includes a delivery motor 62 that rotates the delivery drum 22, a drum rotation motor 61 that rotates the image forming drum 21, and each drive unit of the paper feeding unit 3. A paper feed motor 63 that drives each of the driving sources of the stacking unit 4, a head drive circuit 65 that drives the ink discharge unit 51 (head unit 51a), a drum temperature sensor 91, For the operator to set and input the degree of gloss of the formed image, the heating roller 71 of one heating unit, the heating unit temperature sensor 92, the heating roller 72, the suction unit 212, the UV lamp 52, the cooling fan 53, and the like. The gloss adjustment button 68, the recording medium thickness input unit 81, and the recording medium type input unit 82 are electrically connected.

The control means 10 includes a ROM that stores a program for controlling each component of the inkjet recording apparatus 1, a CPU that executes the program, a RAM that is a work area when the program is executed, and the like. .
Further, the control means 10 is provided with an image memory circuit 67 for storing the formed image data input from the host computer as the host device via the interface circuit 66. The CPU of the control means 10 performs calculations based on image data and programs stored in the image memory circuit 67, and transmits control signals to each component based on the calculation results.
The control unit 10 functions as a heating control unit that controls the heating of the heating roller 71.

The recording medium thickness input unit 81 is used for an operator to input the thickness of the recording medium P on which image formation is performed, and the recording medium type input unit 82 is used to input the type of recording medium P on which image formation is performed. Is.
The control means 10 performs heating control according to the thickness and type of the recording medium P. Specifically, the control means 10 stores table data that defines the set temperatures T4 and T5 of the heating roller 71 based on the two parameters of the type and thickness of the recording medium P, and the set temperature T4 and T5 are input by these inputs. Processing to determine T5 is performed.
The heating roller 71 is provided to quickly raise the recording medium P to a desired temperature range, and T4 and T5 are determined by the thermal conductivity of the heating roller 71, the contact time with the recording medium P, and the like. .

  The table below shows an example of table data in which the set temperatures T4 and T5 are determined by the two parameters of the type and thickness of the recording medium P. All temperatures in the table are expressed in Celsius. In the table, T1 is a lower limit value of the image forming drum set temperature range indicating the target temperature band of the image forming drum 21 during image formation, T2 is an intermediate value of the image forming drum set temperature range, and T3 is image forming. This is the upper limit value of the set temperature range of the drum 21.

(ink)
The ink used in the present invention is an actinic ray curable ink that cures when irradiated with energy rays (actinic rays such as ultraviolet rays). 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 whole 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 a sol-gel phase transition is in a liquid state at a high temperature, and thus can be ejected by an inkjet 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 droplets is strong, the dots are isolated from each other, resulting in unevenness in the image area, which may cause 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 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 to 5 ° C. or more and 15 ° C. or less, printing can be achieved with high image quality and natural glossiness by preventing ink droplet coalescence. Coexistence is possible. In this case, the temperature control range of the medium corresponds to 42 ° C. or higher and 48 ° C. or lower.

  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.
Using the actinic ray curable ink described in the present invention, the image quality deterioration is caused by adjusting the difference between the gel temperature (Tgel) of the ink and the surface temperature (Ts) of the recording medium to 5 ° C. or more and 15 ° C. or less. It is possible to form images with excellent sharpness of fine lines such as characters and natural glossiness, but the temperature of the recording medium should be adjusted to a range of 5 ° C to 10 ° C. This makes it possible to form a better image.

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 glyco- 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 any compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule may be used. , 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, isopropenyl ether -o- propylene carbonate, dodecyl ether, diethylene glycol monovinyl ether, 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 Seika Kogyo), 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, HosteBem G2 , Hostaperm 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 diameter of the pigment particles is 0.08 to 0.5 μm, and the maximum particle diameter 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, 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, manufactured by Bayer Japan), KAYASET Yellow SF-G, KAYASET Yellow 2G, KAYASET Yellow AG, KAYASET Yellow EG (above, manufactured by 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 fin 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 Thioxanthone series such as 1,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone; amino benzophenone series such as Michler-ketone, 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. Sci.), Vol. 30, page 174 (1986), (oxo) sulfonium organoboron complexes described in Japanese Patent Nos. 2711491 and 2803454, 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.

  As described above, the ink jet recording apparatus 1 can directly form an image on the recording medium P on the image forming drum 21 by the ink discharge unit 51 (recording head 510). Compared with an image forming apparatus that transfers an image to P, high-quality image formation can be performed.

Further, the ink jet recording apparatus 1 according to the present invention can individually move any of the plurality of ink discharge portions 51 to the maintenance position R2 in a direction away from the image forming drum 21, and When the worker enters the exterior portion 20 through the door portion 20a and the door portion 20b, the worker can approach from both sides of the ink discharge portion 51 moved to the maintenance position R2.
Then, a predetermined maintenance operation can be performed with two workers sandwiching the one ink discharge portion 51 moved to the maintenance position R2 from both sides, and therefore, a plurality of recordings are recorded on the head portion 51a of the ink discharge portion 51. Even if the heads 510 are arranged in a plurality of rows, the operator can easily see each recording head 510 and can easily clean or replace the recording head 510.

  On the other hand, for example, when the plurality of ink ejection portions 51 are integrally moved to the maintenance position R2 as in the prior art, it is difficult to reach the ink ejection portion 51 that is far from the worker. It is difficult to perform maintenance. In particular, since the gap between the adjacent ink discharge portions 51 is narrow, it is difficult to perform maintenance of the ink discharge portions 51 from the gap. Even if two workers can enter both sides of the plurality (here, four) of the ink discharge portions 51 and the maintenance of the two outer ink discharge portions 51 can be performed, the two inner ink discharge portions 51 The maintenance of 51 cannot be performed satisfactorily.

  As described above, an arbitrary ink discharge portion 51 among the plurality of ink discharge portions 51 can be individually moved to the maintenance position R2, and an operator can be moved from both sides of the ink discharge portion 51 moved to the maintenance position R2. It can be said that the inkjet recording apparatus 1 that can be approached is an inkjet recording apparatus that facilitates maintenance of the head portion 51a.

  The application of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Image forming part 3 Paper feeding part 4 Stacking part 20 Exterior part 20a, 20b Door part 21 Image forming drum 51 Ink ejection part 51a Head part 51b Carriage 510 Recording head 52 UV lamp P Recording medium R1 Print position R2 Maintenance position

Claims (3)

An inkjet recording apparatus that records on a recording medium by discharging ink,
An image forming drum that holds and conveys the recording medium on its outer peripheral surface;
A plurality of head portions that form an image by ejecting the ink onto the recording medium that is arranged in the conveyance direction of the recording medium and conveyed by the image forming drum;
A carriage that supports the plurality of head portions so as to be individually movable at a print position for forming an image and a maintenance position that is separated from the image forming drum in a direction that intersects the transport direction;
An exterior portion that houses the image forming drum, the plurality of head portions, and the carriage;
The ink jet recording apparatus according to claim 1, wherein the exterior portion is provided with at least two door portions capable of entering two places sandwiching the head portion moved to the maintenance position.   The head section includes a plurality of recording heads that eject the ink, and the plurality of recording heads are arranged in a plurality of rows along a direction that intersects the transport direction. The inkjet recording apparatus according to claim 1.   The inkjet recording apparatus according to claim 1, wherein the ink is an energy beam curable ink.

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