JP2011201125A - Ink jet recorder and ink jet recording method - Google Patents

Abstract

[PROBLEMS] To suppress the penetration of water or solvent contained in ink into a recording medium to prevent the occurrence of curling and cockle, to improve the drying efficiency and to increase the speed of recording, and to prevent color shift and image shift. To achieve high image quality.
A processing liquid application unit that applies a processing liquid to a recording medium conveyed by the conveyance unit, a liquid ejection head that ejects aqueous ultraviolet curable ink disposed downstream in the conveyance direction, and Inkjet recording comprising: a semi-curing unit disposed downstream thereof; a drying unit for the recording medium disposed further downstream; and a main curing unit disposed further downstream. The problem is solved by providing an apparatus.
[Selection] Figure 3

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method, and in particular, prints on a recording medium by printing with a water-based ultraviolet curable ink from the ink jet head on a recording medium that is transported relative to the ink jet head. The present invention relates to an ink jet recording apparatus and an ink jet recording method for curing and fixing ink.

  Conventionally, in an ink jet recording method using ultraviolet curable ink, when forming a color image, an image formed with each color ink is finally irradiated with ultraviolet light collectively, and each color ink is applied. There are cases where ultraviolet light is irradiated every time the ink is discharged.

  Since UV curable ink does not solidify unless it is irradiated with UV light, when ink droplets land on a recording medium, the ink penetrates or diffuses into the recording medium, and adjacent ink dots are connected to each other. Flows and the position of the dot moves, causing a problem that the image is blurred.

  In addition, since ink is ejected sequentially, if ink droplets of different colors are adjacent to each other on the recording medium, bleeding or color mixing may occur, and a desired color tone may not be obtained or color boundaries may be blurred. As a result, the image is not sharp.

  In order to solve these problems, an ink jet recording apparatus has been proposed in which various devices are used when printing is performed using ultraviolet curable ink and cured with ultraviolet rays.

  For example, in Patent Document 1, a recording with an image formed with a saddle-shaped curved surface partially transmitting ultraviolet light for the purpose of achieving downsizing of the apparatus while preventing bleeding, color mixing, color misregistration and bleeding. From the inside of the transport mechanism that transports the medium, the ink is sequentially pre-cured by irradiating ultraviolet light toward the back side of the recording medium ejected for each recording head, and then further irradiating the ultraviolet light from the front side. An image forming apparatus that fully cures the ink has been proposed.

  Also, for example, in Patent Document 2, curing is performed by irradiating ultraviolet rays that semi-cure landing ink droplets between ink jet heads for different colors in order to prevent image quality deterioration due to intercolor bleeding and to prevent ink in the nozzles from curing. By means and handling (rubbing between the rollers, conveyance guides, etc. and the image surface in the downstream conveying process of the main curing, rubbing between prints in the print stacking unit, rubbing by various objects when actually handling the finished print, etc.) There has been proposed an image forming apparatus provided with a curing means for irradiating with ultraviolet rays for performing main curing to such an extent that image deterioration does not occur.

  In addition, for example, the ink is maintained in a semi-cured state even after being irradiated with ultraviolet rays a plurality of times, so that intermediate processing can be surely performed, and glossy image fixing is realized, and color mixing between different color inks during color image formation is achieved. Two types of UV curing initiators that do not overlap spectral absorption characteristics for the purpose of preventing image quality degradation (including initiators that start curing only by irradiation by a semi-curing means and initiators that start curing by irradiation by a main curing means) And by discharging the ultraviolet curable ink containing the monomer and the coloring material, the ultraviolet curable ink maintains a semi-cured state on the recording medium even if the ink dots are irradiated by the semi-curing means a plurality of times. There has been proposed an image forming apparatus provided with a full line head capable of reliably performing intermediate processing such as pressure fixing and intermediate transfer.

JP 2005-193527 A JP-A-2005-280346 JP 2007-112117 A

  However, since the configuration described in Patent Document 1 is configured to irradiate ultraviolet light from the inside of the drum toward the back surface of the recording medium, the recording medium is a material that can transmit ultraviolet light, or the ultraviolet light penetrates the gaps in the fibers. In the case of plain paper, such as copy paper, the penetration can be suppressed by semi-curing the lower part of the ink droplets, but the recording medium is made of ultraviolet light such as thick coated paper. In the case of absorbing a large amount of water, the amount of light reaching the ink is insufficient, so that there is a problem that sufficient curing cannot be expected.

  Moreover, in the thing of the said patent document 2, since the semi-hardening means is arrange | positioned between the inkjet heads according to color, from the fixing member which mounts a recording head, an ink supply, a signal supply line, and an ultraviolet light irradiation part. Since one head unit is arranged in parallel in the transport direction for the number of colors, the structure is complicated and the size and cost of the apparatus are increased, and the distance between the recording heads is increased. Due to the increase in length, there is a problem that image shift such as intercolor shift and contour shift occurs.

  Moreover, in the thing of the said patent document 3, since a general ultraviolet light source (a xenon lamp, an ultrahigh pressure mercury lamp, a metal halide lamp) has a broadband spectral distribution, one of two types of initiators is selectively used. It is difficult to start curing. Instead, LEDs or laser diodes with a narrow band emission distribution in the ultraviolet light region may be used. However, these light sources are expensive, so an apparatus that attempts to achieve high productivity by arranging the light sources in a linear form High cost is inevitable. Further, for example, when a plurality of initiators are mixed in the pigment ink, there is a problem that the dispersion stability deteriorates.

  In addition, in the ink jet recording method using water-based ink, ink droplets are ejected and landed on the recording medium, so that ink moisture soaks into the recording medium such as paper, so that the cockle (the recording medium is absorbed by water absorption of the recording medium). There is a problem that a phenomenon called “expansion deformation” occurs and the recording quality is lowered.

  In particular, as the resolution of an ink jet recording apparatus increases and the speed of recording increases, the ink jet head has a tendency to increase the number of discharge ports and increase the number of discharge ports. In this way, in the case of a system that performs high-speed printing in a single pass using a long head that is arranged with high density and is fixed, it is necessary to increase the drying efficiency and suppress the cuckling in the high-speed recording. is there.

  The present invention has been made in view of such circumstances, and suppresses the penetration of water and solvent contained in the ink into the recording medium, prevents the occurrence of curling and cockle, improves the drying efficiency, and records. It is an object of the present invention to provide an ink jet recording apparatus and an ink jet recording method capable of achieving high image quality and achieving high image quality by preventing color shift and image shift.

  In order to achieve the above object, the invention described in claim 1 provides a conveying means for conveying a recording medium and a treatment liquid for aggregating components in the ink composition to the conveyed recording medium. A treatment liquid applying unit; a liquid discharge head disposed on the downstream side in the transport direction with respect to the treatment liquid applying unit; and discharging water-based ultraviolet curable ink to the recording medium; A semi-curing means disposed on the downstream side in the transport direction and semi-cured by irradiating ultraviolet rays to the water-based ultraviolet curable ink ejected onto the recording medium by the liquid ejection head; A drying unit disposed on the downstream side in the transport direction and configured to dry the recording medium; Further comprising a curing means for curing by irradiating ultraviolet rays to the aqueous UV curable ink which is to provide an ink jet recording apparatus characterized.

  As described above, in the present invention, since the processing liquid is applied to the recording medium before drawing, the color material flow on the recording surface, the color material bleeding, the color mixture between the color inks, the landing interference between the ink droplets, and the like. In addition, since the capillaries are formed by aggregating the solid components contained in the ink on the recording surface, it is possible to suppress the penetration of water or solvent contained in the ink into the recording medium. Also, since the ink is semi-cured after drawing and before drying, the viscosity of the ink is increased, so that the penetration of water and solvent contained in the ink into the recording medium can be suppressed, and the occurrence of curling and cockle due to the penetration can be suppressed. . In addition, since water and solvent accumulate near the surface of the recording surface, the drying efficiency in subsequent drying is improved.

  In addition, since the ink is semi-cured in a lump after ejecting multiple colors of ink, it is not necessary to install an ultraviolet irradiation section between the heads for each color, increasing the size and cost of the device. Can be avoided. Furthermore, since the interval between the heads for each color can be reduced, color shift and image shift can be prevented, and high-speed recording can be performed.

  In addition, due to the main curing, rubbing between an image surface and a roller, a conveying guide, etc. in the conveying process on the downstream side, rubbing between prints in the print stacking unit, rubbing by various objects when handling the finished print, etc. It is possible to achieve high image quality.

  According to a second aspect of the present invention, the conveying means for conveying the recording medium to the drying means has a conveying surface on which a plurality of suction holes for sucking the recording medium from the back surface are formed. The recording medium is sucked onto the transport surface and transported.

  Thus, by adsorbing and drying, the occurrence of curling and cockle can be suppressed. Furthermore, since the ink is semi-cured before drying, the flow of ink is suppressed, and the ink is unlikely to collect in the suction holes during the suction drying.

  According to a third aspect of the present invention, the transport means includes the liquid discharge head disposed opposite the outer peripheral surface of the first drum, and rotates and transports the recording medium while holding the recording medium on the outer peripheral surface of the first drum. However, the drawing drum configured to discharge the water-based ultraviolet curable ink from the liquid discharge head toward the recording medium, and the drying means are disposed to face the outer peripheral surface of the second drum, A drying drum configured to dry the recording medium by the drying means while holding and rotating the recording medium on the outer peripheral surface of the second drum, and disposed between the drawing drum and the drying drum And holding means for holding the leading edge of the recording medium, holding the recording medium by the holding means and rotating and conveying the recording medium from the drawing drum to the drying drum. Characterized in that it comprises a carrier, a.

  By adopting the drum conveyance method in this way, it is possible to realize high productivity and high image quality.

  According to a fourth aspect of the present invention, the semi-curing means is disposed inside the first intermediate transport body.

  Thus, by disposing the semi-curing means on the first intermediate transport body, the ink is cured on the nozzle surface of the ink-jet head by being semi-cured by the transfer cylinder transport means separated from the ink-jet head, and thus the ejection failure. Can be reduced.

  According to a fifth aspect of the present invention, the drying drum has a plurality of suction holes for suctioning the recording medium from the back surface on the outer peripheral surface thereof, and the recording medium is adsorbed on the outer peripheral surface. It is characterized by being conveyed.

  In this way, curling and cockle generation can be suppressed by adsorbing and drying even in the case of drum conveyance. Furthermore, since the ink is semi-cured before drying, the flow of ink is suppressed, and the ink is unlikely to collect in the suction holes during the suction drying.

  Further, according to a sixth aspect of the present invention, the conveying means is further provided with the main curing means facing the outer peripheral surface of the third drum to hold the recording medium on the outer peripheral surface of the third drum. A fixing drum configured to perform main curing of the recording medium by the main curing unit while being rotationally transported, and a holding unit that is disposed between the drying drum and the fixing drum and holds a leading end of the recording medium. And a second intermediate transport body that holds and rotates the recording medium by the holding means and delivers the recording medium from the drying drum to the fixing drum.

  High productivity and high image quality can be realized by carrying the drum.

  Similarly, in order to achieve the above object, the invention according to claim 7 includes a step of applying a treatment liquid for aggregating components in the ink composition to the recording medium conveyed by the conveying means; Subsequent to the treatment liquid application step, a drawing step of drawing aqueous ultraviolet curable ink onto the recording medium to draw on the recording medium, and the aqueous step discharged onto the recording medium following the drawing step. A semi-curing step for semi-curing the ultraviolet curable ink by irradiating ultraviolet rays, a drying step for drying the recording medium following the semi-curing step, and a discharge step after the drying step. And a main curing step of irradiating the water-based ultraviolet curable ink with ultraviolet rays for main curing.

  Thereby, it is possible to suppress the penetration of water and solvent contained in the ink into the recording medium, suppress the occurrence of curling and cockle, improve the drying efficiency, and improve the image quality and the recording speed.

  In the drying step, the recording medium is sucked from the back surface side of the recording medium to the transport surface by a negative pressure by a transport unit having a transport surface in which a plurality of suction holes are formed. It is characterized by being conveyed.

  Thus, by adsorbing and drying, the occurrence of curling and cockle can be suppressed.

  Further, as shown in claim 9, in each step, the recording medium is held and conveyed on the outer peripheral surface of each rotating conveyance drum, and between the conveyance drums in each step, the recording medium is The intermediate transfer body disposed between the transfer drums is transferred from the transfer drum of the preceding process to the transfer drum of the subsequent process.

  Thus, high productivity and high image quality can be realized by drum transport.

  In addition, according to a tenth aspect of the present invention, the recording medium drawn in the drawing step is subjected to the drawing step by an intermediate conveyance body arranged between the conveyance drum in the drawing step and the conveyance drum in the drying step. It is semi-cured while being transferred from the transfer drum to the transfer drum in the drying step.

  In this way, semi-curing when transported by the intermediate transport body results in semi-curing by the transfer cylinder transport means away from the ink-jet head, and ejection failure due to ink curing on the nozzle surface of the ink-jet head Can be reduced.

  In addition, as shown in claim 11, the transport drum in the drying step is formed with a plurality of suction holes for suctioning the recording medium from the back surface on the outer peripheral surface thereof, and the recording medium is placed on the outer peripheral surface. It is characterized in that it is adsorbed and transported.

  In this way, curling and cockle generation can be suppressed by adsorbing and drying even in the case of drum conveyance.

  As described above, according to the present invention, water and solvent contained in ink are prevented from penetrating into the recording medium, curling and clogging are prevented, drying efficiency is improved, and recording speed is increased. In addition, color shift and image shift can be prevented, and high image quality can be achieved.

1 is a schematic configuration diagram illustrating an embodiment of an inkjet recording apparatus according to the present invention. It is a principal part block diagram which shows the system configuration | structure of the inkjet recording device of this embodiment. It is a block diagram which shows the principal part of the inkjet recording device of this embodiment. It is a schematic block diagram which shows the inkjet recording device provided with the belt conveyance means.

  Hereinafter, an ink jet recording apparatus and an ink jet recording method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram showing an embodiment of an ink jet recording apparatus according to the present invention.

  As shown in FIG. 1, the ink jet recording apparatus 100 according to the present embodiment mainly includes a paper feeding unit 112, a treatment liquid application unit 114, a drawing unit 116, a drying unit 118, a fixing unit 120, and a paper discharge unit 122. It is configured.

  The ink jet recording apparatus 100 has an ink jet head 172 (172M (magenta), 172K (black), 172C (cyan), 172Y (172Y) on the recording surface of the recording medium P held on the pressure drum (drawing drum 170) of the drawing unit 116. Yellow)) is an impression cylinder direct drawing type ink jet recording apparatus that forms a desired color image by ejecting a plurality of colors of water-based ultraviolet curable ink, and a treatment liquid is applied onto the recording medium P before the ink is ejected. (Including an aggregating agent for aggregating components in the ink composition) and applying a two-liquid reaction (aggregation) method in which an image is formed on the recording medium P by reacting the treatment liquid and the ink liquid. Type image forming apparatus.

  The paper feeding unit 112 is a mechanism that supplies the recording medium P to the processing liquid application unit 114, and the recording media P that are sheets are stacked on the paper feeding unit 112. The paper feed unit 112 is provided with a paper feed tray 150, and the recording medium P is fed from the paper feed tray 150 to the processing liquid application unit 114 one by one. Here, in order to prevent the recording medium P from being lifted, the paper feed tray 150 may be provided with a suction hole on the outer surface and connected to a suction unit that performs suction from the suction hole.

  In the ink jet recording apparatus 100 of the present embodiment, a plurality of types of recording media P having different paper types and sizes (paper sizes) can be used as the recording medium P. A mode in which a plurality of paper trays (not shown) for collecting and recording various recording media P in the paper feeding unit 112 is provided, and the paper to be fed to the paper feeding tray 150 is automatically switched from among the plurality of paper trays is also possible. There is also a mode in which the operator selects or replaces the paper tray as necessary. In this example, a sheet (cut paper) is used as the recording medium P. However, a configuration in which a continuous paper (roll paper) is cut to a required size and fed is also possible.

  The processing liquid application unit 114 is a mechanism that applies the processing liquid to the recording surface of the recording medium P. The treatment liquid includes an aggregating agent that agglomerates the components in the ink composition applied by the drawing unit 116, and causes an aggregation reaction with the ink when the treatment liquid comes into contact with the ink. Separation is promoted, and it is possible to form a high-quality image without causing blurring after ink landing, landing interference (unification), or color mixing. In addition, as a process liquid, it can also comprise using another component other than a coagulant | flocculant as needed. By using the treatment liquid together with the ink composition, it is possible to increase the speed of ink jet recording, and an image with excellent density and resolution can be obtained (for example, reproducibility of fine lines and fine portions) even at high speed recording. The processing liquid will be described in detail later.

  As shown in FIG. 1, the treatment liquid application unit 114 includes a paper supply drum 152, a treatment liquid drum 154, and a treatment liquid application device 156. The treatment liquid drum 154 is a drum that holds the recording medium P and rotates and conveys it. The processing liquid drum 154 includes a claw-shaped holding means (gripper) 155 on the outer peripheral surface thereof, and the recording medium P is sandwiched between the claw of the holding means 155 and the outer peripheral surface of the processing liquid drum 154 so that the recording medium P The tip can be held. The treatment liquid drum 154 may be provided with a suction hole on its outer peripheral surface and connected to a suction means for performing suction from the suction hole. Accordingly, the recording medium P can be held in close contact with the outer peripheral surface of the processing liquid drum 154.

  A processing liquid coating device 156 is provided outside the processing liquid drum 154 so as to face the outer peripheral surface thereof. In the recording medium P, the processing liquid is applied to the recording surface by the processing liquid application device 156.

  The recording medium P to which the processing liquid is applied by the processing liquid applying unit 114 is transferred from the processing liquid drum 154 to the drawing drum 170 of the drawing unit 116 via the first transfer drum transport unit 126. The first transfer drum transport means 126 includes a guide member 127 with a rib on the lower side thereof, and a holding claw provided at a tip portion of an arm extending in a direction opposite to the rotation shaft by 180 degrees, holds the recording medium P. Grasp the leading end, rotate around the rotation axis, leave the trailing end of the recording medium P free, and place the recording medium P along the guide member 127 so that the back side of the recording surface is convex (first The recording medium P facing the inside of the single transfer drum transport means 126 is configured to be transported in such a manner that the recording surface is concave.

  The drawing unit 116 includes a drawing drum 170 and inkjet heads 172M, 172K, 172C, and 172Y. In addition, a sheet suppression roller for removing wrinkles of the recording medium P may be provided on the front side of the ink jet heads 172M, 172K, 172C, 172Y (upstream in the rotation direction of the drawing drum 170).

  Similar to the treatment liquid drum 154, the drawing drum 170 includes a claw-shaped holding means (gripper) 171 on its outer peripheral surface, and holds and fixes the leading end of the recording medium. The drawing drum 170 has a large number of suction holes on the outer peripheral surface, and the recording medium P is attracted to the outer peripheral surface of the drawing drum 170 by negative pressure. As a result, contact with the head due to paper floating is avoided, and paper jam is prevented. In addition, image unevenness due to fluctuations in the clearance with the head is prevented.

  The recording medium P fixed to the drawing drum 170 in this way is conveyed with the recording surface side convex so that the recording surface faces outward, and the inkjet head 172 (172M, 172K, 172C, 172Y), an aqueous ultraviolet curable ink is ejected.

  The inkjet heads 172 (172M, 172K, 172C, 172Y) are full-line inkjet recording heads (inkjet heads) each having a length corresponding to the maximum width of the image forming area in the recording medium P. On the ejection surface, a nozzle row in which a plurality of nozzles for ejecting ink are arranged over the entire width of the image forming area is formed. Each inkjet head 172M, 172K, 172C, 172Y is installed so as to extend in a direction substantially orthogonal to the conveyance direction of the recording medium P (the rotation direction of the drawing drum 170).

  The droplets of the corresponding color ink are ejected from the respective ink jet heads 172M, 172K, 172C, 172Y toward the recording surface of the recording medium P held tightly on the drawing drum 170, whereby the processing liquid application unit 114 The ink comes into contact with the treatment liquid previously applied to the recording surface, and the color material (pigment) dispersed in the ink is aggregated to form a color material aggregate. As a result, the color material flow on the recording medium P is prevented, and an image is formed on the recording surface of the recording medium P.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special ink are used as necessary. Color ink may be added. For example, it is possible to add an ink jet head that discharges light ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

  The drawing unit 116 configured as described above can perform drawing on the recording medium P in a single pass. Thereby, high-speed recording and high-speed output are possible, and productivity can be improved.

  The recording medium P on which an image is formed by the drawing unit 116 is transferred from the drawing drum 170 to the drying drum 176 of the drying unit 118 via the second transfer drum transport unit 128.

  Similarly to the first transfer drum transport means 126 described above, the second transfer drum transport means 128 includes a guide member 129 with a rib on the lower side thereof, and the tip of an arm extending in a direction facing 180 degrees across the rotation shaft. The front end of the recording medium P is gripped by a holding claw provided in the section, rotates around the rotation axis, and the recording medium P is moved along the guide member 129 while the rear end of the recording medium P is free. The recording surface is conveyed so that the back surface side is convex (the recording surface of the recording medium P facing the inside of the second transfer cylinder conveying means 128 is concave). The second transfer drum transport means 128 corresponds to the first intermediate transport body described in claims 3 and 4, and a semi-curing means is provided in the inside thereof, which will be described in detail later.

  The drying unit 118 is a mechanism that dries moisture contained in the solvent separated by the color material aggregating action, and includes a drying drum 176 and a solvent drying device 178 as shown in FIG.

  Similar to the treatment liquid drum 154, the drying drum 176 includes a claw-shaped holding unit (gripper) 177 on the outer peripheral surface thereof, holds the tip of the recording medium P by the holding unit 177, and suction holes on the outer peripheral surface of the drum. (Not shown), and the back side of the recording medium P can be adsorbed to the drying drum 176 by negative pressure.

  The drying drum 176 has suction holes provided on the outer peripheral surface thereof and suction means for performing suction from the suction holes. As a result, the recording medium P can be held in close contact with the peripheral surface of the drying drum 176. Moreover, since the recording medium P can be restrained by the drying drum 176 by performing negative pressure suction, the recording medium P can be prevented from being clogged.

  Further, a blowing means 180 (smoothing means) and a solvent drying device 178 are provided so as to face the outer peripheral surface of the drying drum 176. The air blowing unit 180 has a function of blowing the recording medium P downstream in the conveyance direction, removing the wrinkles of the recording medium P, and stably adsorbing the recording medium P to the drying drum 176. In other words, the air blowing means 180 applies air obliquely toward the rear end side of the recording medium P, and smoothes the recording medium P held at the front end by the holding means 177 from the front end side toward the rear end side. To suppress the generation of wrinkles so that they are more reliably adsorbed.

  The solvent drying device 178 is arranged at a position facing the outer peripheral surface of the drying drum 176, and includes hot air drying means 182 in which a plurality of combinations of IR heaters and fans are arranged. Various drying conditions can be realized by appropriately adjusting the temperature and air volume of the hot air blown toward the recording medium P from each hot air jet nozzle of the hot air drying means 182. The recording medium P is conveyed while being attracted and restrained to the outer peripheral surface of the drying drum 176 so that the recording surface faces outward and the recording surface side is convex, and the recording surface P is formed by the IR heater and the hot air jet nozzle. A drying process is performed.

  The recording medium P that has been dried by the drying unit 118 is transferred from the drying drum 176 to the fixing drum 184 of the fixing unit 120 via the third transfer drum transport unit 130.

  Similarly to the first transfer drum transfer device 126 and the second transfer drum transfer device 128, the third transfer drum transfer device 130 is also provided with a guide member 131 with a rib on the lower side thereof, and is opposed 180 degrees across the rotation shaft. The tip of the recording medium P is gripped by a holding claw provided at the tip of the arm extending in the direction, rotates around the rotation axis, the rear end of the recording medium P is free, and the guide member 131 is free. The recording medium P is conveyed so that the back surface side of the recording surface is convex (the recording surface of the recording medium P facing the inside of the third transfer cylinder conveying means 130 is concave) along ing. The third transfer drum transport means 130 corresponds to a second intermediate transport body as defined in claim 6.

  The fixing unit 120 includes a fixing drum 184, a pressure roller 188 (smoothing unit), and an ultraviolet light source 190 (main curing unit). Like the processing liquid drum 154, the fixing drum 184 includes a claw-shaped holding unit (gripper) 185 on the outer peripheral surface, and the leading end of the recording medium P can be held by the holding unit 185.

  By the rotation of the fixing drum 184, the recording medium P is conveyed with the recording surface facing outward. The recording surface is smoothed by the pressing roller 188, and then irradiated with ultraviolet rays from the ultraviolet light source 190. The main curing and fixing are performed.

  The pressure roller 188 smoothes the recording medium P by pressurizing the recording medium P from which the ink has been dried.

  The ultraviolet light source 190 irradiates the image formed with the aqueous ultraviolet curable ink ejected onto the recording medium P with ultraviolet rays to perform main curing, thereby fixing the ink.

  An in-line sensor that inspects an image formed on the recording medium P may be provided so as to face the outer peripheral surface of the fixing drum 184. The in-line sensor is a measuring unit for measuring a check pattern, a moisture content, a surface temperature, a glossiness, and the like for an image fixed on the recording medium P. For example, a CCD line sensor can be suitably used.

  Subsequent to the fixing unit 120, a paper discharge unit 122 is provided. A paper discharge unit 192 is installed in the paper discharge unit 122. A transfer drum 194 and a transport chain 196 are provided between the fixing drum 184 and the paper discharge unit 192 of the fixing unit 120. The conveyance chain 196 is wound around the tension roller 198. The recording medium P that has passed through the fixing drum 184 is sent to the transport chain 196 via the transfer drum 194 and is transferred from the transport chain 196 to the paper discharge unit 192.

  Although not shown in FIG. 1, the ink jet recording apparatus 100 of the present example has an ink storage / loading unit that supplies ink to each of the ink jet heads 172M, 172K, 172C, and 172Y, and a treatment liquid application, in addition to the above configuration. A head maintenance unit for supplying a processing liquid to the unit 114 and cleaning the ink jet heads 172M, 172K, 172C, 172Y (wiping, purging, nozzle suction, etc. of the nozzle surface) A position detection sensor for detecting the position of the recording medium P, a temperature sensor for detecting the temperature of each part of the apparatus, and the like are provided.

  FIG. 2 is a principal block diagram showing the system configuration of the inkjet recording apparatus 100.

  The inkjet recording apparatus 100 includes a communication interface 80, a system controller (system controller) 82, an image memory 84, a motor driver 86, a heater driver 88, a print controller 90, a maintenance controller 92, a head driver 94, and the like.

  The communication interface 80 is an interface unit that receives image data sent from the host computer 96. As the communication interface 80, a serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory for speeding up communication may be mounted. The image data sent from the host computer 96 is taken into the ink jet recording apparatus 100 via the communication interface 80 and temporarily stored in the image memory 84.

  The image memory 84 is a storage unit that temporarily stores an image input via the communication interface 80, and data is read and written through the system control unit 82. The image memory 84 is not limited to a memory composed of semiconductor elements, and a magnetic medium such as a hard disk may be used.

  The system control unit 82 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 100 according to a predetermined program. Function. That is, the system control unit 82 controls the communication interface 80, the image memory 84, the motor driver 86, the heater driver 88, and the like, and generates control signals for controlling the heater 99 and the host computer 96.

  The image memory 84 stores programs executed by the CPU of the system control unit 82 and various data necessary for control. Note that the image memory 84 may be a non-rewritable storage means or a rewritable storage means such as an EEPROM. The image memory 84 may be used as a temporary storage area for image data, and may be used as a program development area and a calculation work area for the CPU.

  The system control unit 82 is connected to an EEPROM 85 that stores various control programs and an image processing unit 87 that performs various image processes on image data. In response to a command from the system control unit 82, a control program is read from the EEPROM 85 and executed. Note that the EEPROM 85 may also be used as a storage unit for operating parameters and the like.

  The motor driver 86 is a driver that drives the motor 98 in accordance with an instruction from the system control unit 82. In FIG. 2, the motor (actuator) disposed in each part of the inkjet recording apparatus 100 is represented by reference numeral 98. For example, the motor 98 shown in FIG. 2 includes motors that drive the intermediate transport units 126, 128, and 130, the transfer drum 152, the processing liquid drum 154, the drawing drum 170, the drying drum 176, and the fixing drum 184 shown in FIG. It is.

  The heater driver 88 is a driver that drives the heater 99 in accordance with an instruction from the system control unit 82. In FIG. 2, a plurality of heaters provided in the ink jet recording apparatus 100 are represented by reference numeral 99. For example, the heater 99 shown in FIG. 2 includes the heater of the treatment liquid application unit 114 and the IR heater of the drying unit 118 shown in FIG.

  In addition, a maintenance control unit 92 is connected to the system control unit 82. The maintenance control unit 92 controls a maintenance drive unit 93 that drives a maintenance unit (not shown) including a cap and a cleaning blade in accordance with an instruction from the system control unit 82.

  The print control unit 90 has a signal processing function for performing various processes and corrections for generating a print control signal from the image data in the image memory 84 under the control of the system control unit 82. The controller is a controller that controls the treatment liquid application driver 95 to apply the treatment liquid to the recording medium P from the treatment liquid application device 156 and supplies the generated print data (dot data) to the head driver 94. . Necessary signal processing is performed in the print control unit 90, and the ejection droplet amount (droplet ejection amount) and ejection of the inkjet head 172 (172M, 172K, 172C, 172Y) via the head driver 94 based on the image data. Timing control is performed. Thereby, a desired dot size and dot arrangement are realized.

  The system controller 82 is connected with a UV irradiation means driver 97 for controlling the ultraviolet light source (main curing means) 190 and the semi-curing means 189.

  FIG. 3 is an enlarged view of the treatment liquid application unit 114, the drawing unit 116, the drying unit 118, and the fixing unit 120, which are main parts of the inkjet recording apparatus 100 of the present embodiment, and the inkjet recording apparatus according to the present invention is described in more detail. explain.

  As shown in FIG. 3, the processing liquid drum 154, the first transfer drum transport means 126, the drawing drum 170, the second transfer drum transport means 128 (first intermediate transport body), the drying drum 176, the third transfer drum transport means. 130 (second intermediate conveyance body) and the fixing drum 184 are arranged side by side, and a semi-curing means 189 is provided inside the second transfer cylinder conveyance means 128 (first intermediate conveyance body) for fixing. The drum 184 is provided with an ultraviolet light source (main curing means) 190. Then, while the recording medium P is transported by the respective drums and transport means, the treatment liquid application, drawing, semi-curing, drying, and main curing (fixing) are sequentially performed.

  The main curing here refers to rubbing between an image surface and a roller, a conveying guide, or the like in the downstream conveying step of the main curing unit 190, rubbing between prints in a print stacking unit, or a finished print actually. A state in which the ink droplets on the recording medium P are cured to such an extent that the image is not deteriorated even when handling such as rubbing by various objects during handling. Therefore, the main curing does not necessarily mean that the curing reaction is completed.

  Further, semi-curing means that the ink on the recording medium P is cured to such an extent that it is not yet fully cured in the above-mentioned meaning and is in a flexible ink state.

  The ink jet recording apparatus 100 of the present embodiment records an image on a recording surface of a recording medium P. The recording medium P is not particularly limited, but is so-called high-quality paper used for general offset printing or the like. Ordinary printing paper mainly composed of cellulose, such as coated paper or art paper, can be used. General printing paper mainly composed of cellulose is relatively slow in ink absorption and drying in image recording by a general ink jet method using water-based ink, and color material movement is likely to occur after droplet ejection, and image quality is likely to deteriorate. However, the inkjet recording apparatus 100 of the present embodiment can perform high-quality image recording excellent in color density and hue by suppressing color material movement.

  Of the recording media, so-called coated paper used for general offset printing is preferred. The coated paper is obtained by applying a coating material to the surface of high-quality paper, neutral paper, or the like that is mainly surface-treated with cellulose as a main component and is not surface-treated. The coated paper is liable to cause quality problems such as glossiness and scratch resistance of the image in normal aqueous inkjet image formation. However, in the inkjet recording apparatus 100 of the present embodiment, gloss unevenness is suppressed and glossiness is reduced. An image having good abrasion resistance can be obtained. In particular, a coated paper having a base paper and a coat layer containing an inorganic pigment is preferably used, and a coated paper having a base paper and a coat layer containing kaolin and / or calcium bicarbonate is more preferably used. Specifically, art paper, coated paper, lightweight coated paper, or finely coated paper is more preferable.

  As described above, the processing liquid application unit 114 applies the processing liquid to the recording surface of the recording medium P.

  The film thickness of the processing liquid applied to the recording surface by the processing liquid coating apparatus 156 is sufficiently smaller than the droplet diameter of the ink ejected from the inkjet heads 172M, 172K, 172C, 172Y of the drawing unit 116. Is desirable. For example, when the ink droplet ejection amount is 2 pl (picoliter), the average diameter of the droplets is 15.6 μm. At this time, when the film thickness of the processing liquid is large, the ink dots float in the processing liquid without contacting the surface of the recording medium P. Therefore, in order to obtain a landing dot diameter of 30 μm or more when the ink droplet ejection amount is 2 pl, it is desirable that the film thickness of the treatment liquid is 3 μm or less.

Although not shown in the figure, the processing liquid coating device 156 is mainly composed of a processing liquid container, a metering roller, and a coating roller. A processing liquid is stored in the processing liquid container, and a part of the measuring roller is immersed in the processing liquid. As the metering roller, a metal roller and an anilox roller in which a large number of cells are regularly formed with a certain number of lines on a roller peripheral surface having a ceramic coating on the surface of the metal roller are preferably used. As the material of the metal roller, iron, SUS, or the like is used. When iron is used as the material, the surface may be plated with chromium or the like in order to improve surface hydrophilicity, wear resistance, and rust resistance. As the cell structure of the anilox roller, for example, those having 150 to 400 lines, a cell depth of 20 to 75 μm, and a cell capacity of 30 cm ³ / m ^{2 to} 60 cm ³ / m ² can be suitably used. . The diameter of the measuring roller is, for example, 20 mm or more and 100 mm or less.

  The metering roller is rotatably supported and connected to a motor (not shown), and is driven to rotate at a constant speed. Therefore, the processing liquid in the processing liquid container can be attached to the surface of the measuring roller, and this processing liquid can be transferred to the surface of the coating roller. The rotation direction of the metering roller may be the same as that of the application roller, and the peripheral speed of the outer periphery of the roller may be the same as that of the application roller, or a speed difference may be provided. When providing a speed difference, the peripheral speed of the metering roller is preferably 80% or more and 140% or less with respect to the peripheral speed of the application roller. By adjusting the peripheral speed between the application roller and the metering roller, the transfer rate from the metering roller to the application roller can be adjusted, and the coating film thickness on the recording medium P can be adjusted.

  A metering doctor blade is provided on the surface of the metering roller so as to come into contact therewith. The doctor blade is arranged on the upstream side in the rotation direction of the measuring roller with respect to the contact position between the measuring roller and the applying roller, and can measure the application liquid by scraping off the application liquid on the surface of the measuring roller. Thereby, the coating liquid measured by the doctor blade can be supplied to the coating roller.

  As the coating roller, a rubber roller having a rubber layer such as EPDM or silicon on the surface is preferably used. The application roller is rotatably supported and connected to a motor (not shown) and is driven to rotate at a constant speed. The rotation direction of the application roller is the same as that of the processing liquid drum 154, and the peripheral speed of the roller outer periphery is also rotated at the same speed as that of the processing liquid drum 154. As a result, the processing liquid transferred from the metering roller to the application roller is applied to the recording medium P held on the processing liquid drum 154.

  As described above, since the processing liquid application device 156 applies the processing liquid with the roller, it is possible to apply the processing liquid to the recording medium P uniformly and with a small application amount. Further, the processing liquid coating device 156 contacts and separates the rollers of the processing liquid coating unit for each recording medium so as not to contaminate the processing liquid coating conveyance drum (processing liquid drum 154). It is preferable. The treatment liquid drum 154 conveys the recording medium P with a holding claw that holds the tip of the recording medium P. As a result, the recording medium P can be conveyed at high speed, and the occurrence of paper conveyance jams can be reduced.

Note that an IR heater and a hot air jet nozzle may be provided opposite to the outer peripheral surface of the processing liquid drum 154 to dry the processing liquid applied to the recording medium P. When an IR heater or a warm air ejection nozzle is provided, the IR heater is controlled to a high temperature (for example, 180 ° C.), and the warm air ejection nozzle generates a high temperature (for example, 70 ° C.) of warm air at a constant air volume (for example, 9 m). ³ / min) and sprayed toward the recording medium P. By the heating by the IR heater and the hot air jet nozzle, moisture in the solvent of the processing liquid is evaporated, and a thin film layer of the processing liquid is formed on the recording surface of the recording medium P. By thinning the treatment liquid in this way, the ink dots ejected by the drawing unit 116 come into contact with the recording surface of the recording medium P, and the necessary dot diameter can be obtained, and the thinned treatment liquid component Reacts with the colorant to cause aggregation of the coloring material, and an effect of fixing to the recording surface of the recording medium P is easily obtained. The processing liquid drum 154 may be controlled to a predetermined temperature (for example, 50 ° C.).

  Further, the treatment liquid contains an aggregating agent that aggregates the components in the ink composition applied by the drawing unit 116.

  The aggregating agent may be a compound capable of changing the pH of the ink composition, a polyvalent metal salt, or polyallylamines. In the present embodiment, from the viewpoint of the cohesiveness of the ink composition, a compound that can change the pH of the ink composition is preferable, and a compound that can lower the pH of the ink composition is more preferable. Preferred examples of the compound capable of lowering the pH of the ink composition include highly water-soluble acidic substances (phosphoric acid, oxalic acid, malonic acid, citric acid, derivatives of these compounds, and salts thereof).

  As described above, as the flocculant, an acidic substance having high water solubility is preferable, and an organic acid is preferable and an organic acid having a valence of 2 or more is more preferable from the viewpoint of improving the aggregation property and fixing the entire ink. Furthermore, an acidic substance having a valence of 2 to 3 is particularly preferable. As the divalent or higher organic acid, an organic acid having a first pKa of 3.5 or less is preferable, and an organic acid of 3.0 or less is more preferable. Specifically, phosphoric acid, oxalic acid, malonic acid, Preferred examples include citric acid.

  In the flocculant, the acidic substance may be used alone or in combination of two or more. Thereby, cohesion can be improved and the whole ink can be fixed. The content of the flocculant for aggregating the ink composition in the treatment liquid is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and still more preferably 5 to 40% by mass. is there. Further, it is preferable that the pH (25 ° C.) of the ink composition is 8.0 or more and the pH (25 ° C.) of the treatment liquid is in the range of 0.5 to 4. As a result, it is possible to increase the image density, resolution, and speed of inkjet recording.

  Further, the processing liquid can contain other additives. These additives include anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, UV absorbers, antiseptics, anti-fungal agents, pH adjusters, surface tension adjusters, antifoaming agents, Well-known additives, such as a viscosity modifier, a dispersing agent, a dispersion stabilizer, a rust preventive agent, and a chelating agent, are mentioned.

  As described above, in this embodiment, the configuration in which the application method using the roller is applied is exemplified, but the application of the treatment liquid is not limited to the application method, and is performed by applying a known method such as an inkjet method or an immersion method. be able to. The coating method can be performed by a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or the like.

  The treatment liquid application step may be provided either before or after the ink application step using the ink composition. In the present embodiment, an aspect in which the ink application process is provided after the treatment liquid is applied in the treatment liquid application process is preferable. Specifically, before the ink composition is applied on the recording medium P, a treatment liquid for aggregating the pigment and / or self-dispersing polymer particles in the ink composition is applied in advance. An embodiment in which an ink composition is applied so as to come into contact with the treatment liquid applied on the medium P to form an image is preferable. Thereby, inkjet recording can be speeded up, and an image with high density and resolution can be obtained even at high speed recording.

The amount of the treatment liquid applied is not particularly limited as long as the ink composition can be aggregated. However, the amount of the aggregation agent applied is preferably an amount that makes the amount of the aggregation agent 0.1 g / m ² or more. Especially, the quantity from which the provision amount of a flocculant will be 0.2-0.7 g / m < ² > is preferable. When the applied amount of the flocculant is 0.1 g / m ² or more, good high-speed flocculence can be maintained according to various usage forms of the ink composition. Moreover, it is preferable that the application amount of the flocculant is 0.7 g / m ² or less from the viewpoint that the surface property of the applied recording medium P is not adversely affected (change in gloss, etc.).

  The processing liquid application unit 114 records the processing liquid while measuring the processing liquid by the processing liquid coating device 156 while holding and transporting the leading end portion of the recording medium P by the holding means 155 provided on the outer peripheral surface of the processing liquid drum 154. A treatment liquid is applied to the medium P.

  The recording medium P to which the processing liquid is applied by the processing liquid applying unit 114 is conveyed to the next drawing unit 116 by the first transfer cylinder conveying unit 126. The recording medium P is held at its leading end by a holding claw (not shown) of the first transfer drum conveying means 126, and conveyed so that the recording surface faces inward and the back surface is convex along the guide member 127. Is done.

  Further, the first transfer drum transport means 126 has hot air drying means (not shown) inside (near the rotation axis), and blows hot air on the recording surface (front surface) side of the recording medium P facing inward during transport. The treatment liquid applied to the surface is dried. Accordingly, when ink is ejected onto the recording medium P in the drawing unit 116, the landing ink is prevented from moving on the recording medium P when the ink is attached.

  The drawing drum 170 of the drawing unit 116 holds the leading end portion of the recording medium P conveyed by the first transfer drum conveying unit 126 by the holding unit 171 provided on the outer peripheral surface of the drawing drum 170 and the outer periphery of the drawing drum 170. The recording medium P is sucked and fixed to the outer peripheral surface of the drawing drum 170 by a suction hole provided on the surface and conveyed. Aqueous ultraviolet curable ink is then applied from the inkjet heads 172M, 172K, 172C, 172Y toward the surface (recording surface) of the recording medium P fixed to the outer peripheral surface of the drawing drum 170, to which the processing liquid is applied. Dropped.

  Here, the ink (aqueous ultraviolet curable ink) used in the present invention will be described.

  The aqueous ultraviolet curable ink includes a pigment, polymer particles, and a water-soluble polymerizable compound that is polymerized by active energy rays. Thereby, it can be hardened by irradiating with ultraviolet rays, and has excellent abrasion resistance and high film strength.

  The ink composition in the present invention contains a pigment, and can be constituted using a dispersant, a surfactant, and other components as necessary. The ink composition contains at least one pigment as a color material component. There is no restriction | limiting in particular as a pigment, According to the objective, it can select suitably, For example, any of an organic pigment and an inorganic pigment may be sufficient. The pigment is preferably a pigment that is almost insoluble or hardly soluble in water from the viewpoint of ink colorability. The pigment is preferably a water-dispersible pigment in which at least a part of its surface is coated with a polymer dispersant.

  The ink composition of the present invention can contain at least one dispersant. The dispersant for the pigment may be either a polymer dispersant or a low molecular surfactant type dispersant. The polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.

  The weight average molecular weight of the polymer dispersant is preferably 3,000 to 100,000, more preferably 5,000 to 50,000, still more preferably 5,000 to 40,000, particularly preferably. 10,000 to 40,000.

  The acid value of the polymer dispersant is preferably 100 KOHmg / g or less from the viewpoint of good aggregation when the treatment liquid comes into contact. Furthermore, the acid value is more preferably 25 to 100 KOH mg / g, further preferably 25 to 80 KOH mg / g, and particularly preferably 30 to 65 KOH mg / g. When the acid value of the polymer dispersant is 25 or more, the stability of self-dispersibility is improved.

  The polymer dispersant preferably contains a polymer having a carboxyl group from the viewpoint of self-dispersibility and aggregation rate when the treatment liquid comes into contact, and the polymer dispersant has a carboxyl group and an acid value of 25 to 80 KOHmg / g. More preferably.

  In the present embodiment, from the viewpoint of light resistance and quality of the image, it is preferable to include a pigment and a dispersant, more preferably to include an organic pigment and a polymer dispersant, and further to include an organic pigment and a carboxyl group. It is particularly preferred to contain a polymer dispersant. Moreover, it is preferable that a pigment is coat | covered with the polymer dispersing agent which has a carboxyl group from a cohesive viewpoint, and is water-insoluble. Furthermore, from the viewpoint of cohesiveness, it is preferable that the acid value of the self-dispersing polymer particles described below is smaller than the acid value of the polymer dispersant.

  The average particle size of the pigment is preferably 10 to 200 nm, more preferably 10 to 150 nm, and even more preferably 10 to 100 nm. When the average particle diameter is 200 nm or less, the color reproducibility is good, and the droplet ejection characteristics when droplets are ejected by the ink jet method are good, and when it is 100 nm or less, the light resistance is good. Further, the particle size distribution of the color material is not particularly limited, and may be either a wide particle size distribution or a monodisperse particle size distribution. Two or more color materials having a monodisperse particle size distribution may be mixed and used.

  The average particle size and particle size distribution of the pigment are determined by measuring the volume average particle size by a dynamic light scattering method using a nanotrack particle size distribution measuring device UPA-EX150 (manufactured by Nikkiso Co., Ltd.). Is.

  You may use a pigment individually by 1 type or in combination of 2 or more types. The content of the pigment in the ink composition is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and more preferably 5 to 20% by mass with respect to the ink composition from the viewpoint of image density. Is more preferable, and 5 to 15% by mass is particularly preferable.

(Polymer particles)
The ink composition in the invention can contain at least one kind of polymer particles. The polymer particles have a function of fixing the ink composition by increasing the viscosity of the ink by aggregation and dispersion instability when contacted with a treatment liquid described later or a dried region thereof. It is possible to further improve the fixing property of an object to a recording medium and the scratch resistance of an image.

  In order to react with the aggregating agent, polymer particles having an anionic surface charge are used, and generally known latex is used as long as sufficient reactivity and ejection stability are obtained. It is preferable to use polymer particles.

(Self-dispersing polymer particles)
The ink composition in the invention preferably contains at least one kind of self-dispersing polymer particles as polymer particles. This self-dispersing polymer has a function of fixing the ink composition by destabilizing and agglomerating and aggregating the ink to increase the viscosity of the ink when it comes into contact with a treatment liquid described later or a dried region thereof. Fixability of the composition to a recording medium and image scratch resistance can be further improved. Self-dispersing polymers are also preferred resin particles from the viewpoints of ejection stability and liquid stability (particularly dispersion stability) of the system containing the pigment.

  Self-dispersing polymer particles are water-insoluble polymers that can be dispersed in an aqueous medium by the functional groups (especially acidic groups or salts thereof) of the polymer itself in the absence of other surfactants. Means water-insoluble polymer particles which do not contain free emulsifiers.

  The acid value of the self-dispersing polymer in the present invention is preferably 50 KOHmg / g or less from the viewpoint of good cohesiveness when the treatment liquid comes into contact. Further, the acid value is more preferably 25 to 50 KOH mg / g, and further preferably 30 to 50 KOH mg / g. When the acid value of the self-dispersing polymer is 25 or more, the stability of the self-dispersing property is improved.

  The self-dispersing polymer particles in the present invention preferably contain a polymer having a carboxyl group from the viewpoint of self-dispersibility and agglomeration speed when the treatment liquid comes into contact. More preferably, it contains a polymer of 50 KOH mg / g, more preferably a polymer having a carboxyl group and an acid value of 30 to 50 KOH mg / g.

  The molecular weight of the water-insoluble polymer constituting the self-dispersing polymer particles is preferably 3,000 to 200,000, more preferably 5,000 to 150,000 in terms of weight average molecular weight, and 10,000 to 10,000. More preferably, it is 100,000. By setting the weight average molecular weight to 3,000 or more, the amount of water-soluble components can be effectively suppressed. Moreover, self-dispersion stability can be improved by making a weight average molecular weight into 200,000 or less.

  The weight average molecular weight is measured by gel permeation chromatography (GPC). For GPC, HLC-8220GPC (manufactured by Tosoh Corporation) is used, and as columns, TSKgeL SuperHZM-H, TSKgeL SuperHZ4000, TSKgeL SuperHZ2000 (manufactured by Tosoh Corporation, 4.6 mm ID × 15 cm) are used as eluents. Use THF (tetrahydrofuran). As conditions, the sample concentration was 0.35 / min. The flow rate is 0.35 ml / min. The sample injection volume is 10 μl, the measurement temperature is 40 ° C., and an IR detector is used. In addition, calibration curves are manufactured by Tosoh Corporation, “Standard sample TSK standard, polysrene”, “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”. , “A-2500”, “A-1000”, “n-propylbenzene”.

  The average particle size of the self-dispersing polymer particles is preferably in the range of 10 nm to 400 nm, more preferably in the range of 10 to 200 nm, and still more preferably in the range of 10 to 100 nm. When the volume average particle size is 10 nm or more, the production suitability is improved, and when it is 1 μm or less, the storage stability is improved.

  The average particle size and particle size distribution of the self-dispersing polymer particles are measured by the dynamic light scattering method using Nanotrac particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.). Is required.

  The self-dispersing polymer particles can be used singly or in combination of two or more. The content of the self-dispersing polymer particles in the ink composition is preferably 1 to 30% by mass with respect to the ink composition from the viewpoint of aggregation rate and image glossiness, and 5 to 15 More preferably, it is mass%.

  In addition, the content ratio of the pigment and the self-dispersing polymer particles in the ink composition (for example, water-insoluble pigment particles / self-dispersing polymer particles) is 1 / 0.0 from the viewpoint of image scratch resistance. 5 to 1/10 is preferable, and 1/1 to 1/4 is more preferable.

(Polymerizable compound)
The ink composition in the present invention can contain at least one water-soluble polymerizable compound that is polymerized by active energy rays.

  As the polymerizable compound, a nonionic or cationic polymerizable compound is preferable in that the reaction between the flocculant, the pigment, and the polymer particles is not hindered. The term “water-soluble” means that it can be dissolved in water at a certain concentration or higher, and it can be dissolved in water-based ink (preferably uniformly). Further, the solubility may be increased by adding a water-soluble organic solvent, and it may be dissolved (desirably uniformly) in the ink. Specifically, the solubility in water is preferably 10% by mass or more, and more preferably 15% by mass or more.

  As the polymerizable compound, a nonionic or cationic polymerizable compound is preferable in that the reaction between the flocculant, the pigment, and the polymer particles is not hindered, and the solubility in water is 10% by mass or more (more preferably 15% by mass or more). The polymerizable compound is preferable.

  As the polymerizable compound in the present invention, a polyfunctional monomer is preferable from the viewpoint of enhancing scratch resistance, and a bifunctional to hexafunctional monomer is preferable, and from the viewpoint of compatibility between solubility and scratch resistance, bifunctional to tetrafunctional. Are preferred.

  A polymeric compound can be contained individually by 1 type or in combination of 2 or more types.

  The content of the polymerizable compound in the ink composition is preferably 30 to 300% by mass, more preferably 50 to 200% by mass, based on the total solid content of the pigment and the self-dispersing polymer particles. When the content of the polymerizable compound is 30% by mass or more, the image strength is further improved and the image has excellent scratch resistance, and when it is 300% by mass or less, it is advantageous in terms of pile height.

  At least one of the ink composition and the treatment liquid further includes an initiator that initiates polymerization of the polymerizable compound by active energy rays.

(Initiator)
The ink composition in the present invention may contain at least one initiator that initiates polymerization of the polymerizable compound by active energy rays with or without being contained in the treatment liquid. A photoinitiator can be used individually by 1 type or in mixture of 2 or more types or using together with a sensitizer.

  The initiator can contain a compound capable of initiating a polymerization reaction by active energy rays as appropriate. For example, the initiator starts generation of active species (radicals, acids, bases, etc.) by radiation or light, or electron beams. An agent (for example, a photopolymerization initiator) can be used.

  When the initiator is contained, the content of the initiator in the ink composition is preferably 1 to 40% by mass and more preferably 5 to 30% by mass with respect to the polymerizable compound. When the content of the initiator is 1% by mass or more, the scratch resistance of the image is further improved, which is advantageous for high-speed recording, and when it is 40% by mass or more, it is advantageous in terms of ejection stability.

(Water-soluble organic solvent)
The ink composition in the invention can contain at least one water-soluble organic solvent. The water-soluble organic solvent can obtain the effect of preventing drying, wetting or promoting penetration. In order to prevent drying, the ink adheres to and drys at the ink discharge port of the ejection nozzle and is used as an anti-drying agent to prevent clogging. For drying prevention and wetting, the vapor pressure is lower than that of water. A water-soluble organic solvent is preferred. Further, for penetration promotion, it can be used as a penetration enhancer that enhances ink permeability to paper.

  The drying inhibitor is preferably a water-soluble organic solvent having a vapor pressure lower than that of water.

  Anti-drying agents may be used alone or in combination of two or more. The content of the drying inhibitor is preferably in the range of 10 to 50% by mass in the ink composition.

  The penetration accelerator is suitable for the purpose of allowing the ink composition to penetrate better into the recording medium (printing paper or the like). A penetration enhancer may be used individually by 1 type, or may be used together 2 or more types. The content of the penetration enhancer is preferably in the range of 5 to 30% by mass in the ink composition. Moreover, it is preferable to use the penetration enhancer within a range that does not cause image bleeding and paper loss (print-through).

(water)
The ink composition contains water, but the amount of water is not particularly limited. Among these, the preferable content of water is 10 to 99% by mass, more preferably 30 to 80% by mass, and still more preferably 50 to 70% by mass.

(Other additives)
The ink composition in the present invention can be constituted using other additives in addition to the above components. Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, anti-fungal agents, pH adjusters, surface tension adjusters, Well-known additives, such as a foaming agent, a viscosity modifier, a dispersing agent, a dispersion stabilizer, a rust preventive agent, a chelating agent, are mentioned.

  Returning to FIG. 3 again, the drawing unit 116 discharges droplets of the corresponding color ink from the respective ink jet heads 172M, 172K, 172C, and 172Y toward the recording surface of the recording medium P held tightly on the drawing drum 170. As a result, the ink comes into contact with the treatment liquid applied to the recording surface in advance by the treatment liquid application unit 114, and the color material (pigment) dispersed in the ink is aggregated to form a color material aggregate. As a result, the color material flow on the recording medium P is prevented, and an image is formed on the recording surface of the recording medium P.

  The amount of ink droplets ejected from each of the inkjet heads 172M, 172K, 172C, and 172Y is preferably 1 to 10 pl (picoliter) and more preferably 1.5 to 6 pl from the viewpoint of obtaining a high-definition image. preferable. In addition, from the viewpoint of improving the unevenness of the image and the connection between the continuous gradations, it is also effective to discharge different droplet amounts in combination, and the present invention is suitably applied even in such a case.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special ink are used as necessary. Color ink may be added. For example, it is possible to add an ink jet head that discharges light ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

  The drawing unit 116 configured as described above can perform drawing on the recording medium P in a single pass. As a result, high-speed recording and high-speed output are possible, and productivity is high.

  The recording medium P on which an image is formed by the drawing unit 116 is transferred from the drawing drum 170 to the drying drum 176 of the drying unit 118 via the second transfer cylinder transport unit 128 (first intermediate transport body). The second transfer drum transport unit 128 holds the recording medium P received from the drawing drum 170 by a holding claw (not shown), the recording surface of the recording medium P faces inward, and the back surface side is a guide member. 129 is conveyed so as to have a convex shape.

  The second transfer drum transport unit 128 includes a semi-curing unit 189 inside, and irradiates the recording surface of the recording medium P conveyed toward the inside of the second transfer drum transport unit 128 with ultraviolet light. Then, the water-based ultraviolet curable ink deposited on the recording surface is semi-cured. Here, the semi-curing means to make a flexible ink state that has not yet been fully cured as described above.

  The light source of the semi-curing unit 189 is not particularly limited, and for example, a metal halide lamp, a mercury lamp, an excimer laser, an ultraviolet laser, a black light, a cold cathode tube, an LED, a laser diode, or the like can be applied. A light emitting diode or a laser diode having a narrow emission wavelength region as compared with the light source of 120 main curing means 190 is preferably used.

  The peak wavelength and emission wavelength region of the light source are appropriately selected according to the absorption characteristics of the sensitizing dye in the ink composition used.

  The semi-curing by the semi-curing means 189 functions to make the aqueous ultraviolet curable ink ejected onto the recording medium P by the ink jet head 172 in the drawing unit 116 into a soft ink state that is not fully cured, and to increase the viscosity. Thus, the water and the solvent contained in the ink serve to suppress the occurrence of curling and cockle due to the penetration of the inside of the recording medium P.

  In addition, the 2nd transfer cylinder conveyance means 128 (1st intermediate conveyance body) does not have a hot-air drying means inside. This is for the purpose of restraining and drying in the subsequent drying unit 118 (drying unit) to prevent cockle.

  The recording medium P semi-cured by the semi-curing unit 189 in the second transfer cylinder transport unit 128 (first intermediate transport body) is delivered to the drying drum 176 of the drying unit 118.

  The drying unit 118 is a mechanism for drying moisture contained in the solvent separated by the color material aggregating action. As shown in FIG. 3, the IR heater is disposed at a position facing the drying drum 176 and the outer peripheral surface of the drying drum 176. It is comprised with the hot-air drying means 182 which has arrange | positioned multiple combinations of a fan and the like. Further, a baffle plate may be provided so that the hot air from the hot air drying means 182 can be reused to improve the thermal efficiency and the exhaust performance.

  In addition, a blowing unit (smoothing unit) 180 is provided on the upstream side of the plurality of hot air drying units 182 in the drum rotation direction so as to face the outer periphery of the drying drum 176. The air blowing means 180 is for blowing air onto the recording medium P, assisting the adsorption of the recording medium P to the drying drum 176, and smoothing the recording medium P adsorbed by the drying drum 176.

  Air blowing to the recording medium P by the air blowing unit 180 is controlled so that the wind force is increased at the rear end of the recording medium P. As a result, the sheet floating at the rear end of the recording medium P can be prevented. Further, the air blowing unit 180 blows air so as to be applied obliquely toward the rear end side of the recording medium P. Further, the air blowing unit 180 blows air so as to be applied obliquely toward the end of the recording medium P in the paper width direction.

  As described above, the air blowing unit 180 removes the suction traps of the drying drum 176 of the recording medium P by applying air obliquely toward the rear end side of the sheet and further toward the rear end side in the width direction, and is uniform. Drying and uniform adsorption are possible.

  Note that if the suction assistance to the drying drum 176 is performed by the contact means instead of the air blowing means 180, the undried ink is transferred to the contact means, which may cause an image defect. Therefore, it is preferable that the air blowing unit 180 assists the suction of the recording medium P to the drying drum 176 as described above.

  The drying drum 176 holds the leading end of the recording medium P by the holding means 177, sucks and adsorbs the recording medium P from a plurality of suction holes formed on the outer peripheral surface with negative pressure, and restrains the recording medium P so as to be in close contact with it. Thus, the recording medium P is dried by applying hot air to the recording medium P adsorbed by the drying drum 176 from the hot-air jet nozzle of the hot-air drying means 182.

  This prevents the occurrence of cockle. Further, by causing the recording medium P to be in close contact with the outer peripheral surface of the drying drum 176, it is possible to prevent the occurrence of jam and paper burning due to the recording medium P coming into contact with the hot air drying means 182.

The hot air ejection nozzle of the hot air drying means 182 is configured to blow hot air controlled at a predetermined temperature (for example, 50 ° C. to 70 ° C.) toward the recording medium 124 at a constant air volume (12 m ³ / min). Each IR heater is controlled to a predetermined temperature (for example, 180 ° C.). By these hot air jet nozzles and IR heaters, moisture contained in the recording surface of the recording medium P held on the drying drum 176 is evaporated and a drying process is performed. At that time, since the drying drum 176 of the drying unit 118 is structurally separated from the drawing drum 170 of the drawing unit 116, a head meniscus portion by thermal drying is used in the inkjet head 172 (172M, 172K, 172C, 172Y). Ink ejection due to drying of the ink can be reduced. Further, there is a degree of freedom in setting the temperature of the drying unit 118, and an optimal drying temperature can be set.

  In addition, it is preferable to discharge | evaporate the evaporated water | moisture content outside with the air by the discharge means which abbreviate | omitted illustration. Further, the collected air may be cooled by a cooler (radiator) or the like and collected as a liquid.

  Further, it is preferable that the outer peripheral surface of the drying drum 176 is controlled to a predetermined temperature. Drying is promoted by heating from the back surface of the recording medium P, and image destruction during fixing can be prevented. The range of the surface temperature of the drying drum 176 is preferably 50 ° C. or higher, more preferably 60 ° C. or higher. The upper limit is not particularly limited, but is preferably 75 ° C. or lower from the viewpoint of safety of maintenance work such as cleaning ink adhering to the surface of the drying drum 176 (preventing burns due to high temperature).

  The drying drum 176 is preferably heated to a predetermined temperature before the recording medium P is conveyed. By drying the drying drum 176, drying can be promoted, so that image destruction can be prevented and cuckling can be prevented. The heating temperature is preferably in the same temperature range as the surface temperature of the drying drum 176.

  Heating is preferably performed at a predetermined temperature in the sucked state in order to prevent a temperature drop when sucked. In addition, when heating is performed without suction, it is preferable to perform heating so that the temperature is higher than a predetermined temperature in consideration of a decrease in temperature at the time of suction. Further, the recording medium P is held so that the recording surface of the recording medium P faces outward (that is, in a state where the recording surface of the recording medium 124 is curved so as to be a convex side), and is dried while being rotated and conveyed. Generation | occurrence | production of the wrinkles and floating of P can be prevented, and the drying nonuniformity resulting from these can be prevented reliably.

  The suction force of the drying drum 176 can be expressed by (opening area) × (pressure per unit area). The suction force can be increased by increasing the area occupied by the suction holes in the recording medium suction holding region, that is, the aperture ratio.

  Further, the opening ratio of the suction holes provided on the outer peripheral surface of the drying drum 176 is preferably 1% or more and 75% or less with respect to the contact area between the outer peripheral surface of the drying drum 176 and the recording medium P. Thereby, suppression and prevention of cockle and improvement of drying performance can be aimed at.

  If the aperture ratio is less than 1%, expansion deformation of the recording medium P due to water absorption after recording cannot be sufficiently suppressed. The drying drum 176 itself is also warmed, and the drying of the recording medium P is promoted by coming into contact with the recording medium P. When the opening ratio exceeds 75%, the back surface of the recording medium P and the outer peripheral surface of the drying drum 176 are separated. This is because, since the contact area is reduced, sufficient drying performance cannot be obtained even in a state where the recording medium P is held by suction, and the cockle is also deteriorated.

  Therefore, by setting the opening ratio of the suction holes on the outer peripheral surface of the drying drum 176 to 1% or more and 75% or less, it is possible to prevent the suppression of cockle and improve the drying performance.

  The aperture ratio is set by the diameter of the suction holes, the hole pitch, the shape and arrangement of the holes. The hole diameter is preferably designed to be not less than 0.4 mm and not more than 1.5 mm so as not to cause a dent mark (suction mark) of the recording medium P due to negative pressure suction. The hole pitch is preferably from 0.1 mm to 5 mm in order to prevent thermal deformation of the outer peripheral surface of the drying drum 176 and to ensure rigidity. This is because if the distance between the holes is too large, the effect of suppressing deformation of the recording medium P is insufficient, and the generation of wrinkles cannot be suppressed so much. Further, the shape of the suction hole is preferably a shape with rounded corners because stress is concentrated at the corners if there are corners (acute angles).

  In the rotary conveyance body, the deformation amount of the recording medium P due to the adsorption pressure is larger in the axial direction than in the circumferential direction. Therefore, the suction hole is formed in an elliptical shape or a long hole shape in which the circumferential direction is the major axis direction and the axial direction is the minor axis direction, thereby equalizing the circumferential deformation and the axial deformation of the recording medium P. You can also.

  Further, the recording medium P is held on the outer peripheral surface of the drying drum 176 so that the recording surface of the recording medium P faces outward (that is, in a state where the recording surface of the recording medium P is convex), and is rotated and conveyed. However, by drying, it is possible to prevent the recording medium P from wrinkling and floating, and it is possible to reliably prevent uneven drying due to these.

  The recording medium P dried by the drying unit 118 is conveyed to the fixing unit 120 by the third transfer cylinder conveyance unit 130 (second intermediate conveyance body). At this time, the front end of the recording medium P is held by a holding claw (not shown) of the third transfer drum transport unit 130, the recording surface faces inward, the rear end side is free, and the back side is a guide. It is conveyed along the member 131 so as to have a convex shape.

  As a result, the recording medium P that has been dried while being sucked and constrained by the drying drum 176 in the drying unit 118 is temporarily released, and the recording medium P is bent in the reverse direction to correct the recording medium P. Flatten to prevent curling.

  The third transfer drum transport means 130 has a hot air drying means (drying means) (not shown) inside, and blows hot air on the recording surface side of the recording medium P facing the inside during the conveyance to the surface. The ejected ink is dried. As a result, the drying unevenness caused by the suction holes of the drying drum 176 in the drying unit 118 can be made uniform.

  The hot air drying means provided inside the third transfer drum transport means 130 may be blown air, and the temperature thereof is lower than that of the hot air drying means 182 of the drying unit 118 to reduce power consumption.

  When the fixing drum 184 of the fixing unit 120 receives the recording medium P from the third transfer drum transport unit 130, the fixing drum 184 holds the leading end of the recording medium P by the holding unit 185 provided on the outer peripheral surface of the fixing drum 184, and the drum The recording medium P is sucked and adsorbed by negative pressure from a plurality of suction holes formed on the outer peripheral surface, restrained so as to be in close contact, and wound around the outer peripheral surface to be conveyed.

  Note that the method by which the fixing drum 184 attracts the recording medium P to the outer peripheral surface thereof is not limited to such a method using negative pressure suction, and may be a method such as electrostatic adsorption.

  The recording medium P which is wound around the outer peripheral surface of the fixing drum 184 and conveyed is pressed by a pressing roller (smoothing means) 188 disposed opposite to the fixing drum 184 and pressed against the fixing drum 184 to curl. Is corrected and wrinkles are removed.

  The pressing roller 188 is disposed so as to be in pressure contact with the fixing drum 184 and constitutes a nip roller with the fixing drum 184. As a result, the recording medium P is sandwiched between the pressing roller 188 and the fixing drum 184 and nipped at a predetermined nip pressure (for example, 0.15 MPa), and smoothing processing is performed.

  Further, the pressing roller 188 may be a heating roller. For example, the pressing roller 188 may be configured as a heating roller in which a halogen lamp is incorporated in a metal pipe such as aluminum having good thermal conductivity, and may be controlled at a predetermined temperature (for example, 60 to 80 ° C.). By heating and pressing the recording medium P with the pressure roller 188 configured as this heating roller, thermal energy equal to or higher than the Tg temperature (glass transition temperature) of the latex contained in the ink is applied, and the latex particles are melted. The unevenness of the image surface of the recording medium P is leveled, and glossiness is obtained.

  Next, the recording medium P is irradiated with ultraviolet rays by a main curing unit (ultraviolet light source) 190 disposed to face the fixing drum 184 and is subjected to main curing, whereby the ink is fixed to the recording medium P. Here, a plurality of the main curing means 190 may be provided. Thereby, by reducing the irradiation intensity of each of the main curing means 190, it becomes possible to increase the curing conditions in the irradiation time, and it is possible to reduce the cost and reduce the heat generation amount of the main curing means 190.

The main curing means 190 is not particularly limited, and for example, a metal halide lamp, a mercury lamp, an excimer laser, an ultraviolet laser, a black light, a cold cathode tube, an LED, a laser diode, and the like can be applied. Tubes, mercury lamp tubes or black light are preferred. Furthermore, a light emitting diode that emits ultraviolet rays having an emission wavelength peak of 350 to 420 nm and a maximum illuminance on the surface of the recording medium of 10 to 2000 mW / cm ² is more preferable.

The peak wavelength of the light source of the main curing unit 190 is, for example, 200 to 600 nm, preferably 300 to 450 nm, and more preferably 350 to 450 nm, although it depends on the absorption characteristics of the sensitizing dye in the ink composition. Is appropriate.
The ultraviolet irradiation amount of the curing means 190 (irradiation energy), for example, 2000 mJ / cm ² or less, or preferably 10 to 2000 mJ / cm ^2, more preferably from 20~1000mJ / cm ^2, more preferably Is suitably 50 to 800 mJ / cm ² .

  In the inkjet recording apparatus 100 of the present invention, the ultraviolet irradiation time is preferably 0.01 to 10 seconds, more preferably 0.1 to 2 seconds, on the recording surface of the recording medium P. Is appropriate.

  Note that the surface temperature of the fixing drum 184 may be set to 50 ° C. or more, for example, and the recording medium P held on the outer peripheral surface of the fixing drum 184 may be heated from the back surface. Thereby, drying of the recording medium P is promoted, image destruction at the time of fixing can be prevented, and the image intensity can be increased by the effect of increasing the image temperature.

  As described above, in the present embodiment, a treatment liquid is first applied to a recording medium and drawn with a water-based ultraviolet curable ink, and then UV-irradiated and semi-cured, and then dried by blowing hot air, and finally finally again. Full curing is performed by irradiating with ultraviolet rays.

  By applying the treatment liquid, color material flow on the recording surface, color material bleeding, color mixing between inks of each color, and landing interference between ink droplets are prevented, and solid components contained in the ink aggregate on the recording surface. As a result, a capillary tube is formed, so that the penetration of water or a solvent contained in the ink into the recording medium can be suppressed.

  Further, the semi-curing increases the viscosity of the ink, so that the penetration of water or solvent contained in the ink into the recording medium can be suppressed, and the occurrence of curling and cockle due to the penetration can be suppressed. Furthermore, since water and a solvent remain in the vicinity of the surface of the recording surface, it is possible to improve the drying efficiency in the drying process performed after the semi-curing.

  Further, since the ink flow is suppressed by the semi-curing, there is an effect that the ink is difficult to be accumulated in the adsorption hole during the adsorption drying.

  In addition, as described above, in this embodiment, since inks are semi-cured collectively after applying a plurality of colors of ink, it is not necessary to install an ultraviolet irradiation unit between the heads for each color. The enlargement and cost increase of the apparatus can be avoided. Furthermore, as a result, the interval between the heads for each color can be shortened, so that color misregistration and image misregistration can be prevented, and the recording medium can be transported at the ink applicator at high speed. As a result, the recording speed can be increased.

  In addition, the main curing prevents the rubbing of the image surface with the roller, the conveyance guide, etc. in the downstream conveying process of the main curing, the rubbing of the prints in the print stacking unit, and the rubbing by various objects when handling the finished print. be able to.

  The embodiment described above is an example of drum conveyance, but the present invention is not limited to the case of drum conveyance, and can be suitably applied to the case of belt conveyance, for example.

  Next, an example of belt conveyance will be briefly described.

  FIG. 4 is a schematic configuration diagram of an ink jet recording apparatus provided with a belt conveying unit.

  As shown in FIG. 4, in the inkjet recording apparatus 200, when the belt conveyance unit 210 that has received the recording medium P from the paper feeding unit 212 conveys the recording medium P, the treatment liquid applying unit 214 is along the conveyance path. The drawing unit 216, the drying unit 218, and the fixing unit 220 are arranged so that the recording medium P on which the image is fixed is discharged to the paper discharge unit 222.

  Here, the processing liquid application unit 214 is configured by an ink jet type processing liquid discharge head 256 that discharges the processing liquid toward the recording medium P, but is not limited thereto.

  The drawing unit 216 is configured by an inkjet head 272 (272M, 272K, 272C, 272Y) that discharges water-based ultraviolet curable ink of each color, and the drying unit 218 is configured by hot air drying means 282 that blows hot air on the recording medium P. ing.

  Note that suction units 270 and 276 for sucking the recording medium P to the transport path are provided below the transport path of the drawing unit 216 and the drying unit 218, respectively. The suction units 270 and 276 are not particularly limited. For example, an infinite number of holes (suction holes) are provided in the transport belt forming the transport path, and the suction unit 270 and 276 is vacuumed by a suction unit connected to the pump from the lower side of the transport belt. You may make it adsorb | suck, and you may make it adsorb | suck and convey the recording medium P to a conveyance path by electrostatic attraction.

  A semi-curing unit 289 is provided between the drawing unit 216 and the drying unit 218 to irradiate the recording medium P on which the aqueous ultraviolet curable ink has been deposited in the drawing unit 216 with ultraviolet rays to semi-cure. . Further, a shielding plate 273 that shields the semi-curing means 289 side of the inkjet head 272 from the ultraviolet rays is preferably disposed so that the ultraviolet rays do not cure the ink in the nozzles of the inkjet head 272.

  A fixing unit 220 including a main curing unit 290 that performs main curing by irradiating the ink on the recording medium P with ultraviolet rays is disposed at the subsequent stage of the drying unit 218.

  The detailed specifications of each part are the same as in the case of drum transport described above.

  As described above, also in the case of belt conveyance, after droplets of water-based ultraviolet curable ink are deposited on the recording medium P, the ink is first semi-cured and then dried, and then main-cured. Has the same effect.

  In the example of drum conveyance described above, the drawing unit 116, the drying unit 118, and the fixing unit 120 are configured as separate drums (the drawing drum 170, the drying drum 176, and the fixing drum 184). The plurality of drums are constituted by one large drum, and along the outer peripheral surface of the one large drum, the drawing unit 116 (inkjet head 172), the drying unit 118 (hot air drying means 182), and the fixing unit 120 ( A main curing means 190) may be arranged. In this case, the semi-curing means 189 may be disposed between the drawing unit 116 and the drying unit 118 so as to face the outer peripheral surface of the large drum.

  Thus, in the case of conveying with one large drum or in the case of belt conveyance, the one large drum or the conveyance belt itself also serves as the intermediate conveyance body in the embodiment of the drum conveyance described above.

  In these examples as well, as in the above-described drum transport embodiment, curling and cockle generation due to ink permeation into the recording medium is suppressed, drying efficiency is improved, and color and image shifts are prevented. High speed recording and high image quality can be realized.

  As described above, the ink jet recording apparatus and the ink jet recording method of the present invention have been described in detail. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

  DESCRIPTION OF SYMBOLS 100 ... Inkjet recording device, 112 ... Paper feed part, 114 ... Processing liquid provision part, 116 ... Drawing part, 118 ... Drying part, 120 ... Fixing part, 124 ... Recording medium, 126 ... 1st transfer cylinder conveyance means, 128 ... Second transfer cylinder transport means (first intermediate transport body), 130 ... Third transfer cylinder transport means (second intermediate transport body), 154 ... treatment liquid drum, 156 ... treatment liquid coating apparatus, 170 ... drawing drum, 172, 172M, 172K, 172C, 172Y ... inkjet head, 176 ... drying drum, 178 ... solvent drying device, 180 ... air blowing means, 182 ... hot air drying means, 184 ... fixing drum, 189 ... semi-curing means, 190 ... main curing Means (ultraviolet light source), 192... Discharge unit, 200... Ink jet recording apparatus, 210... Belt conveying means, P.

Claims (11)

Conveying means for conveying the recording medium;
Treatment liquid application means for applying a treatment liquid for aggregating the components in the ink composition to the transported recording medium;
A liquid discharge head that is disposed on the downstream side in the transport direction with respect to the treatment liquid application unit, and discharges aqueous ultraviolet curable ink to the recording medium;
A semi-curing means disposed on the downstream side in the transport direction with respect to the liquid ejection head, and semi-curing the aqueous ultraviolet curable ink ejected onto the recording medium by the liquid ejection head by irradiating with ultraviolet rays. ,
A drying unit disposed on the downstream side in the transport direction with respect to the semi-curing unit, and drying the recording medium;
A main curing unit that is disposed on the downstream side in the transport direction with respect to the drying unit, and that performs main curing by irradiating the water-based ultraviolet curable ink ejected onto the recording medium by the liquid ejection head with ultraviolet rays;
An ink jet recording apparatus comprising:   The conveying means for conveying the recording medium to the drying means has a conveying surface in which a plurality of suction holes for negatively sucking the recording medium from the back surface are formed, and the recording medium is placed on the conveying surface. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is adsorbed and conveyed. The transport means includes the liquid discharge head disposed opposite the outer peripheral surface of the first drum, and holds the recording medium on the outer peripheral surface of the first drum while rotating and transporting the aqueous medium from the liquid discharge head. A drawing drum configured to discharge ultraviolet curable ink toward the recording medium;
The drying means is disposed opposite the outer peripheral surface of the second drum, and the recording medium is dried by the drying means while the recording medium is held on the outer peripheral surface of the second drum and rotated and conveyed. A dried drum,
A holding unit that is disposed between the drawing drum and the drying drum and holds the tip of the recording medium is held, and the recording medium is held and rotated by the holding unit, and the drawing drum is transferred to the drying drum. A first intermediate carrier for delivering the recording medium;
The inkjet recording apparatus according to claim 1, comprising:   The inkjet recording apparatus according to claim 3, wherein the semi-curing unit is disposed inside the first intermediate conveyance body.   The drying drum is formed with a plurality of suction holes for suctioning the recording medium from the back surface on the outer peripheral surface thereof, and the recording medium is sucked and conveyed on the outer peripheral surface. The ink jet recording apparatus according to 3 or 4.   The conveying means is further arranged with the main curing means facing the outer peripheral surface of the third drum, and while the recording medium is held on the outer peripheral surface of the third drum and rotated and conveyed, A fixing drum configured to fully cure the recording medium; and a holding unit that is disposed between the drying drum and the fixing drum and holds a leading end of the recording medium. And a second intermediate conveyance body that conveys the recording medium from the drying drum to the fixing drum. apparatus. Applying a treatment liquid for aggregating components in the ink composition to the recording medium conveyed by the conveying means;
Subsequent to the treatment liquid application step, a drawing step of drawing water-based ultraviolet curable ink onto the recording medium to draw on the recording medium;
Subsequent to the drawing step, a semi-curing step of semi-curing by irradiating the water-based ultraviolet curable ink discharged onto the recording medium with ultraviolet rays;
Subsequent to the semi-curing step, a drying step of drying the recording medium;
Subsequent to the drying step, a main curing step of irradiating the water-based ultraviolet curable ink ejected on the recording medium with ultraviolet rays for main curing,
An ink jet recording method comprising:   In the drying step, the recording medium is conveyed by negative pressure suction to the conveying surface from the back side of the recording medium by a conveying unit having a conveying surface in which a plurality of suction holes are formed. Item 8. The inkjet recording method according to Item 7.   In each step, the recording medium is held and transported on the outer peripheral surface of each rotating transport drum, and the recording medium is disposed between the transport drums between the transport drums. 8. The ink jet recording method according to claim 7, wherein the ink is transferred from a transport drum in a preceding process to a transport drum in a subsequent process by the body.   The recording medium drawn in the drawing step is transferred from the drawing drum to the drying drum by an intermediate carrier disposed between the drawing drum and the drying drum. 10. The ink jet recording method according to claim 9, wherein the ink is semi-cured during delivery.   The transport drum in the drying step has a plurality of suction holes for suctioning the recording medium from the back surface on the outer peripheral surface thereof, and sucks and transports the recording medium on the outer peripheral surface. The inkjet recording method according to claim 9 or 10.

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