JP5400658B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and an ink jet recording method, and more particularly, to a recording medium conveyed through a large number of drums, printing is performed with aqueous ultraviolet curable ink from an ink jet head, and the recording medium after printing is used. The present invention relates to an ink jet recording apparatus and an ink jet recording method for drying and fixing.

  Conventionally, in an inkjet recording method using water-based ultraviolet curable ink, ink moisture soaks into a recording medium such as paper, and the recording medium absorbs the ink moisture, whereby the recording medium expands and deforms, and wrinkles called cockle are generated, Even after drying, wrinkles and curls remain, causing deterioration in image quality. In addition, if moisture is present in the ink during ultraviolet irradiation, there is a problem that ink curing does not proceed efficiently and high-speed fixing cannot be realized.

  On the other hand, for example, water-based ultraviolet curable ink is not particularly used, but in order to dry the ink on the sheet conveyed by the sheet conveying member in a short time, a plurality of nozzles of the inkjet head are used. After printing by jetting ink on the printing surface, the sheet separated from the sheet conveying member is adsorbed to the outer peripheral surface of the rotating body so that the printing surface faces outward, and is arranged to face the outer peripheral surface of the rotating body There is known an ink jet recording apparatus in which the ink on a sheet is dried by a generated heating element (see, for example, Patent Document 1).

  For example, in an image forming method using water-based ultraviolet curable ink, in order to realize high-speed fixing on a recording medium, hot air is blown on the image by means of hot air blowing to the image to evaporate water and volatile components. Thereafter, an image is cured and fixed by irradiating the ultraviolet ray with the maximum intensity by an ultraviolet ray irradiating means (see, for example, Patent Document 2).

  In addition, for example, an ink jet recording apparatus that controls a holding mechanism so as to release at least a part of the holding of the recording medium and hold it again after applying thermal energy to the recording medium held by the holding mechanism is known ( For example, see Patent Document 3).

JP 2008-179012 A JP 2007-245653 A JP 2007-144773 A

  However, it is difficult to stably adsorb a plurality of types of recording media having various thicknesses without any wrinkles or floats on the suction drying cylinder that sucks the recording medium and adsorbs it to the outer peripheral surface to dry it. When the smoothing member is brought into contact with the image recording surface of the recording medium that has not yet been dried and smoothed so as to remove wrinkles and floats, the recording medium has not yet dried, and thus image distortion and wrinkling will occur. There is a problem that the image becomes defective.

  The present invention has been made in view of such circumstances. A plurality of types of recording media having various thicknesses are stably adsorbed to a recording medium holding cylinder to suppress wrinkles, and uniform drawing and drying. It is an object of the present invention to provide an ink jet recording apparatus and an ink jet recording method capable of performing high quality image recording without image defects.

In order to achieve the object, the invention according to claim 1 is an inkjet head that discharges ink toward a recording medium, a holding unit that holds a tip of the recording medium provided on an outer peripheral surface thereof, and A drum that adsorbs the recording medium to an outer peripheral surface, holds a tip of the recording medium by the holding unit, and adsorbs and rotates the recording medium to the outer peripheral surface; and an outer periphery of the drum A portion of the circumferential direction of the surface that is weak in the suction force of the recording medium is weakened to the outer peripheral surface as the drum rotates over the entire width of the drum. A weakly adsorbing force region forming means that is formed so as to move relative to the recording medium that is transported in the direction opposite to the outer peripheral surface of the drum, and is downstream of the recording medium in the transporting direction of the weakly attracting force region Smell on the side , To provide an ink jet recording apparatus characterized by comprising a, a blowing means for blowing air to the recording medium from the outside of the outer circumferential surface.

As a result, a plurality of types of recording media having various thicknesses are stably adsorbed to the recording medium holding cylinder, wrinkles are suppressed, drawing and drying are performed uniformly, and high-quality image recording without image defects is achieved. Can be done. Further, by blowing air to the downstream side in the conveyance direction of the recording medium in the weak suction force area, the space formed by gathering the folds on the lower side of the recording medium in the weak suction area can be more easily It is possible to move to, and it is possible to remove the wrinkles reliably.

  According to a second aspect of the present invention, the ink jet head is disposed on the drum so as to face the outer peripheral surface of the drum, and ink is ejected from the ink jet head onto the recording medium adsorbed on the outer peripheral surface. The drawing drum is configured as described above.

  According to a third aspect of the present invention, the drum sucks and conveys the recording medium on which the ink is ejected to the outer peripheral surface, and the hot air drying is arranged so that the recording medium is opposed to the outer peripheral surface. A drying drum configured to be dried by means.

  As described above, the present invention can be suitably applied to a drawing drum and a drying drum of an ink jet recording apparatus.

Further, as shown in claim 4, the hot air drying unit, which is characterized by using as the blowing means.

  Thus, since the drying drum already has means for blowing hot air, the apparatus configuration can be simplified correspondingly by using it as blowing means.

According to a fifth aspect of the present invention, the air blowing means blows air obliquely toward the rear end side of the recording medium.

  Thus, the soot can be removed from the rear end side by blowing air obliquely toward the rear end side.

According to a sixth aspect of the present invention, the suction means is a suction means for sucking the recording medium to the outer peripheral surface by sucking air from a suction hole formed on the outer peripheral surface, and the suction force. The weak area forming means divides the suction area formed by arranging the suction holes on the outer peripheral surface into a plurality of areas in the transport direction of the recording medium, and connects each divided area to the suction force generating means. The suction force is controlled for each region .

Thus, by enabling control of the suction force by dividing the suction region into a plurality of regions in each divided region can be formed easily absorption Chakuryokujaku region.

Similarly, in order to achieve the above object, the invention according to claim 7 is an inkjet head that ejects ink toward a recording medium, and a holding that holds the tip of the recording medium provided on the outer peripheral surface thereof. And a drum that sucks the recording medium onto the outer peripheral surface, holds the tip of the recording medium with the holding means, and sucks and rotates the recording medium onto the outer peripheral surface; A part of the outer peripheral surface of the drum in the circumferential direction has a weak suction force region where the suction force of the recording medium is weaker than the other part only over the entire width of the drum. An adsorption force weak region forming unit that is formed so as to move relative to the recording medium that is adsorbed and conveyed by the surface, and the adsorption unit sucks air from the suction holes formed in the outer peripheral surface. By doing Wherein a suction means for adsorbing the recording medium to the outer circumferential surface, also the suction force weak region forming means, provided in fixed within said drum, a suction hole blocking means for closing the suction holes, the The suction hole shielding means is a belt-like plate formed in a belt shape having substantially the same width over the entire width of the outer peripheral surface and opened toward the downstream side in the conveying direction with the central portion in the width direction of the outer peripheral surface serving as a vertex. There is provided an ink jet recording apparatus characterized in that a member is fixed so as not to rotate together with the drum so as to substantially contact along the back surface side of the outer peripheral surface.

Similarly, in order to achieve the object, the invention according to claim 8 is an ink jet head that discharges ink toward a recording medium, and a holding that holds the tip of the recording medium provided on the outer peripheral surface thereof. And a drum that sucks the recording medium onto the outer peripheral surface, holds the tip of the recording medium with the holding means, and sucks and rotates the recording medium onto the outer peripheral surface; A part of the outer peripheral surface of the drum in the circumferential direction has a weak suction force region where the suction force of the recording medium is weaker than the other part only over the entire width of the drum. An adsorption force weak region forming unit that is formed so as to move relative to the recording medium that is adsorbed and conveyed by the surface, and the adsorption unit sucks air from the suction holes formed in the outer peripheral surface. By doing Wherein a suction means for adsorbing the recording medium to the outer circumferential surface, also the suction force weak region forming means, provided in fixed within said drum, a suction hole blocking means for closing the suction holes, the The suction hole shielding means is a plate-like shape formed in a belt-like shape having substantially the same width over the entire width of the outer peripheral surface and a smooth concave shape opened toward the downstream side in the transport direction with the central portion in the width direction of the outer peripheral surface as a vertex. The inkjet recording apparatus is characterized in that the member is fixed so as not to rotate together with the drum so as to be substantially in contact with the back surface side of the outer peripheral surface.

  Thus, by applying the plate-like member to the suction hole, the suction force can be weakened, and the adsorption force weak region can be easily formed.

According to a ninth aspect of the present invention, the drum has the inkjet head disposed opposite the outer peripheral surface of the drum, and ink is ejected from the inkjet head onto the recording medium adsorbed on the outer peripheral surface. The drawing drum is configured as described above .

In addition, according to a tenth aspect of the present invention, the drum sucks and conveys the recording medium on which the ink has been ejected to the outer peripheral surface, and the hot air drying is arranged such that the recording medium is opposed to the outer peripheral surface. it is a drying drum adapted to dry by means.

Similarly, in order to achieve the above object, according to the invention described in claim 11, the recording medium on which ink is ejected from the inkjet head is held at its tip by holding means provided on the outer peripheral surface of the drum. The recording medium is adsorbed to the outer peripheral surface of the drum by the adsorbing means and is formed over the entire width of the drum at a part of the outer peripheral surface of the drum, and only that part is more than the other part. The weak suction force region is formed so as to move relative to the recording medium that is sucked and conveyed by the outer peripheral surface as the drum rotates, and is attracted to the outer peripheral surface of the drum. The recording medium transported in the step is temporarily released in the weak suction force region, and a space is formed between the recording medium and the outer peripheral surface, and then passes through the weak suction force region. Later again By serial suction force is increased, the formed space to provide an ink jet recording method is characterized in that so as to move toward the rear end portion of the recording medium.

  As a result, a plurality of types of recording media having various thicknesses are stably adsorbed to the recording medium holding cylinder, wrinkles are suppressed, drawing and drying are performed uniformly, and high-quality image recording without image defects is achieved. Can be done.

According to a twelfth aspect of the present invention, wind is blown from the outside of the outer peripheral surface to the recording medium on the downstream side in the conveyance direction of the recording medium in the weak suction force region.

  As a result, it is possible to more easily move the space formed by bringing the wrinkles down to the lower side of the recording medium in the weakly adsorbing area, and to reliably remove the wrinkles.

  Further, according to a thirteenth aspect of the present invention, the suction unit is a suction unit that sucks the recording medium onto the outer peripheral surface by sucking air from a suction hole formed on the outer peripheral surface, and is disposed in the drum. The suction force weak region is formed by closing the suction hole by suction hole shielding means fixed so as not to rotate together with the drum.

  Thus, by closing the suction hole, it is possible to easily weaken the suction force and form the weak suction force region.

  As described above, according to the present invention, a plurality of types of recording media having various thicknesses are stably adsorbed to the recording medium holding cylinder, wrinkles are suppressed, drawing and drying are performed uniformly, It is possible to perform high-quality image recording without defects.

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 block diagram which expands and shows the part of a drying drum. It is explanatory drawing which shows the area | region where the suction | attraction force on a drying drum outer peripheral surface is weakened, and a ventilation area | region. (A), (b) is an expanded sectional view which shows the area | region where the attraction | suction force on a drying drum outer peripheral surface is weakened.

  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.

  In the present invention, the suction cylinder for sucking and holding the recording medium rotates while holding the leading end of the recording medium by the holding means provided on the outer peripheral surface thereof, and sucks the entire recording medium to the outer peripheral surface of the suction cylinder. When going, an area where the suction force is weaker than the other part is provided in a part of the outer circumferential surface of the suction cylinder so that the area where the suction force is weak and the recording medium move relative to each other. When passing through a region where the suction force is weak, the suction of the recording medium is temporarily released, and a bend (a space that becomes a wrinkle) is created between the recording medium and the outer peripheral surface. As a result, the suction force increases again after the recording medium passes through the region where the suction force is weak, so that the space that becomes a wrinkle generated between the recording medium and the outer peripheral surface is relatively on the rear end side of the recording medium. To the end of the recording medium. Since take, the recording medium is to be able to stably adsorbed to the outer circumferential surface of the suction cylinder.

  At this time, if the air blowing means is used to blow the downstream side (rotation direction) of the region where the suction force generated by the recording medium is weak in the suction force (rotation direction), the recording space is more reliably placed behind the recording medium. It can be moved to the end side to remove the wrinkles.

  The present invention can be applied to any suction drum that adsorbs a recording medium, for example, a drawing drum, a drying drum, or a treatment liquid drum. However, in the following embodiments, the present invention is applied to a drying drum. A case will be described as an example.

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

  In the inkjet recording apparatus 100, water-based ultraviolet curable inks of a plurality of colors are applied from the inkjet heads 172M, 172K, 172C, and 172Y to the recording surface of the recording medium 124 held by the impression cylinder (drawing drum 170) of the drawing unit 116. It is an impression cylinder direct drawing type ink jet recording apparatus that forms a desired color image by dropping, and a treatment liquid (including an aggregating agent for aggregating components in the ink composition) on the recording medium 124 before ink ejection. And an on-demand type image forming apparatus to which a two-liquid reaction (aggregation) method for forming an image on a recording medium 124 by reacting a treatment liquid and an ink liquid is applied.

  That is, as shown in FIG. 1, the inkjet recording apparatus 100 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. ing.

  The paper feeding unit 112 is a mechanism that supplies the recording medium 124 to the processing liquid application unit 114, and the recording medium 124 that is a sheet is stacked on the paper feeding unit 112. The paper feed unit 112 is provided with a paper feed tray 150, and the recording medium 124 is fed from the paper feed tray 150 to the processing liquid application unit 114 one by one. In order to prevent the recording medium 124 from being lifted, the paper feed tray 150 may be provided with a suction hole on the outer surface, and a suction unit that performs suction from the suction hole may be connected.

  In the inkjet recording apparatus 100 of the present embodiment, a plurality of types of recording media 124 having different paper types and sizes (paper sizes) can be used as the recording medium 124. A mode is also possible in which a plurality of paper trays (not shown) are provided in the paper feed unit 112 to distinguish and collect various recording media and the paper to be fed to the paper feed tray 150 is automatically switched from among the plurality of paper trays. In addition, a mode is also possible 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 124, but a configuration in which 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 124. 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 even with high speed recording (for example, reproducibility of fine lines and fine portions).

  As shown in FIG. 1, the treatment liquid application unit 114 includes a paper feed drum 152, a treatment liquid drum 154, and a treatment liquid application device 156. The treatment liquid drum 154 is a drum that holds and rotates the recording medium 124. The processing liquid drum 154 includes a claw-shaped holding means (gripper) 155 on the outer peripheral surface thereof, and the recording medium 124 is sandwiched between the claw of the holding means 155 and the peripheral surface of the processing liquid drum 154. 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. As a result, the recording medium 124 can be held in close contact with the peripheral surface of the treatment liquid drum 154.

  A processing liquid coating device 156 is provided outside the processing liquid drum 154 so as to face the peripheral surface thereof. In the recording medium 124, the processing liquid is applied to the recording surface by the processing liquid application device 156.

  The recording medium 124 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 intermediate transfer unit 126 (first transfer cylinder transfer unit).

  The drawing unit 116 includes a drawing drum 170 and inkjet heads 172M, 172K, 172C, and 172Y. In addition, a sheet pressing roller for removing the wrinkles of the recording medium 124 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 124 is adsorbed 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 124 thus fixed to the drawing drum 170 is conveyed with the recording surface facing outward, and water-based ultraviolet curable ink is ejected from the inkjet heads 172M, 172K, 172C, 172Y onto this recording surface. Is done.

  The inkjet heads 172M, 172K, 172C, and 172Y are full-line inkjet recording heads (inkjet heads) each having a length corresponding to the maximum width of the image forming area on the recording medium 124. Is formed with a nozzle row in which a plurality of nozzles for ink ejection are arranged over the entire width of the image forming area. Each inkjet head 172M, 172K, 172C, 172Y is installed so as to extend in a direction orthogonal to the conveyance direction of the recording medium 124 (the rotation direction of the drawing drum 170).

  The droplets of the corresponding color ink are ejected from the inkjet heads 172M, 172K, 172C, and 172Y toward the recording surface of the recording medium 124 held in close contact with 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 124 is prevented, and an image is formed on the recording surface of the recording medium 124.

  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 124 in a single pass. Thereby, high-speed recording and high-speed output are possible, and productivity can be improved.

  The recording medium 124 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 intermediate conveyance unit 128 (second transfer cylinder conveyance unit).

  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 processing 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 124 by the holding unit 177, and sucks holes on the outer peripheral surface of the drum. The recording medium 124 can be adsorbed to the drying drum 176 by a 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 124 can be held in close contact with the peripheral surface of the drying drum 176. Further, by performing negative pressure suction, the recording medium 124 can be restrained by the drying drum 176, so that the recording medium 124 can be prevented from being clogged.

  As will be described in detail later, the drying drum 176 has means for creating a region where the suction force of the suction hole is weakened in a part of the circumferential direction. The area where the suction force is weakened is fixed to the rotating drying drum 176, and the recording medium 124 sucked and held by the drying drum 176 and rotated and transported moves relative to the area where the suction force is weakened. It is like that. When the recording medium 124 is applied to the area where the suction force is weakened, the suction is temporarily released, and a gap (a space that becomes a wrinkle) is generated between the recording medium 124 and the outer peripheral surface. Moves to the rear end side of the recording medium 124 and finally exits from the end, so that the recording medium 124 is stably adsorbed to the outer peripheral surface of the drying drum 176 without generating wrinkles.

  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 means 180 blows air toward the downstream side in the transport direction of the recording medium 124 in which a space that becomes a wrinkle is generated in the area where the suction force is weakened, and reliably moves the space that becomes the wrinkle toward the rear end side of the recording medium 124. The recording medium 124 is removed, and the recording medium 124 is stably adsorbed to the drying drum 176. In other words, the air blowing unit 180 blows obliquely toward the end of the recording medium 124 in the width direction, and moves the recording medium 124 held by the holding unit 177 from the leading end side toward the rear end side. Smoothing and suppressing the generation of wrinkles so that it can be adsorbed more reliably. This will be described in detail later.

  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 from each hot air jet nozzle of the hot air drying means 182 toward the recording medium 124. The recording medium 124 is transported 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 is dried by the IR heater and the hot air jet nozzle.

  The recording medium 124 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 intermediate conveyance unit 130 (third transfer cylinder conveyance unit).

  The fixing unit 120 includes a fixing drum 184, a pressure roller 188 (smoothing unit), and an ultraviolet light source 190 (ultraviolet irradiation 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 124 can be held by the holding unit 185.

  With the rotation of the fixing drum 184, the recording medium 124 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. Curing / fixing is performed.

  The pressure roller 188 smoothes the recording medium 124 by pressurizing the recording medium 124 dried with ink.

  The ultraviolet light source 190 irradiates the image formed with the aqueous ultraviolet curable ink discharged on the recording medium 124 with ultraviolet rays to fix the ink.

  An in-line sensor that inspects an image formed on the recording medium 124 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 124. For example, a CCD line sensor can be preferably 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 124 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 124, 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, and also functions as an arithmetic device that performs various calculations. To do. 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 from the treatment liquid application device 156 to the recording medium 124 and supplies the generated print data (dot data) to the head driver 94. . Necessary signal processing is performed in the print controller 90, and the ejection droplet amount (droplet ejection amount) and ejection timing of the inkjet heads 172M, 172K, 172C, 172Y are controlled via the head driver 94 based on the image data. Is done. Thereby, a desired dot size and dot arrangement are realized.

  Further, a UV irradiation means driver 97 for controlling the ultraviolet light source 190 is connected to the system control unit 82.

  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 intermediate transport unit 126 (first transfer drum transport unit), the drawing drum 170, the intermediate transport unit 128 (second transfer drum transport unit), the drying drum 176, and the intermediate transport unit 130. (Third transfer cylinder transporting means) and fixing drum 184 are arranged side by side, and the recording medium 124 is transported by each drum, and while being transported, processing liquid application, drawing, drying, and fixing (curing) are sequentially performed. It has come to be.

  Each intermediate conveyance section (the first transfer drum transfer means 126, the second transfer drum transfer means 128, and the third transfer drum transfer means 130) includes guide members 127, 129, and 131 with ribs, respectively, and sandwiches the rotation shaft. A holding claw (not shown) at the tip of the arm extending in the direction facing 180 degrees grips the tip of the recording medium 124 and rotates around the rotation axis, and the rear end of the recording medium 124 is free. The recording medium 124 is conveyed along the guide members (127, 129, 131) so that the back side of the recording surface is convex.

  The intermediate transport units 126, 128, and 130 may be configured to use a chain gripper to grip the recording medium 124 and transport it with the back side convex.

  The ink jet recording apparatus 100 according to the present embodiment records an image on a recording surface of a recording medium 124. The recording medium 124 is not particularly limited, but is a so-called high-quality paper used for general offset printing. 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 124.

  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 124. 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. 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 124 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 also rotates 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 124 held on the processing liquid drum 154.

  As described above, since the processing liquid coating apparatus 156 applies the processing liquid with the roller, the processing liquid can be uniformly applied to the recording medium 124 with a small coating amount. Further, the processing liquid coating apparatus 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 cylinder (processing liquid drum 154). It is preferable. The treatment liquid drum 154 conveys the recording medium 124 with a holding claw that holds the tip of the recording medium 124. As a result, the recording medium 124 can be conveyed at high speed, and the occurrence of paper conveyance jams can be reduced.

Note that the processing liquid applied to the recording medium 124 may be dried by providing an IR heater and a hot air jet nozzle on the outer periphery of the processing liquid drum 154 so as to face the peripheral surface. 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 124. 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 124. By thinning the treatment liquid in this way, the dots of ink that are ejected by the drawing unit 116 come into contact with the recording surface of the recording medium 124 to obtain the required dot diameter, and the thinned treatment liquid component Reacts with the colorant to cause aggregation of the color material, and an effect of fixing to the recording surface of the recording medium 124 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 applying the ink composition, a treatment liquid for aggregating the pigment and / or self-dispersing polymer particles in the ink composition is applied on the recording medium 124 in advance. A mode in which an image is formed by applying an ink composition so as to come into contact with the treatment liquid applied on the medium 124 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. Further, it is preferable that the amount of the flocculant applied is 0.7 g / m ² or less because the surface properties of the applied recording medium are not adversely affected (such as a change in gloss).

  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 124 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 124.

  The recording medium 124 to which the processing liquid is applied by the processing liquid application unit 114 is conveyed to the next drawing unit 116 by the intermediate conveyance unit (first transfer cylinder conveyance unit) 126. The recording medium 124 is held such that its leading end is held by a holding claw (not shown) of the first transfer drum conveying means 126, and is 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 124 facing inward during transport. The treatment liquid applied to the surface is dried. Thereby, when ink is ejected onto the recording medium 124 in the drawing unit 116, movement of the landing ink on the recording medium 124 at the time of ink adhesion is prevented.

  The drawing drum 170 of the drawing unit 116 holds the leading end portion of the recording medium 124 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 124 is sucked and fixed to the outer peripheral surface of the drawing drum 170 by a suction hole provided on the surface and conveyed. Then, water-based ultraviolet curable ink is applied from the inkjet heads 172M, 172K, 172C, and 172Y toward the surface (recording surface) of the recording medium 124 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. These polymer particles have the function of fixing the ink composition by destabilizing and aggregating when contacted with a treatment liquid described later or a dried region thereof , and aggregating the ink to increase the viscosity. Fixability of the composition to a recording medium and image scratch resistance can be further improved.

  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 thickening 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, and have a carboxyl group and an acid value of 25 to 25. 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 ejects droplets of the corresponding color ink from the inkjet heads 172M, 172K, 172C, and 172Y toward the recording surface of the recording medium 124 held in close contact with 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 124 is prevented, and an image is formed on the recording surface of the recording medium 124.

  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 124 in a single pass.

  The recording medium 124 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 intermediate conveyance unit (second transfer cylinder conveyance unit) 128. The second transfer drum transport unit 128 holds the leading end of the recording medium 124 received from the drawing drum 170 by a holding claw (not shown), the recording surface of the recording medium 124 faces inward, and the back side is a guide member. 129 is conveyed so as to have a convex shape.

  The second transfer drum transport means 128 has a hot air drying means (drying means) (not shown) inside, and blows hot air on the recording surface side of the recording medium 124 facing the inside during the conveyance to the surface. The ejected ink is dried. As a result, since ink can be dried immediately after ink ejection, it becomes easy to reduce the clogging of the recording medium 124 due to ink permeation, and the occurrence of suction flaws at the time of suction restraint in the drying drum 176 in the drying unit 118 is suppressed. It becomes easy to do.

  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 composed of hot air drying means 182 in which a plurality of combinations of fans and the like are arranged. Further, a blowing unit 180 (smoothing unit) is provided on the upstream side (in the rotation direction of the drying drum 176) of the plurality of hot air drying units 182 so as to face the outer periphery of the drying drum 176.

  Similar to the processing liquid drum 154, the drying drum 176 includes a claw-shaped holding unit (gripper) 177 on the outer peripheral surface thereof, and the holding unit 177 can hold the leading end of the recording medium 124. Further, the drying drum 176 has a plurality of suction holes on the outer peripheral surface thereof, and the recording medium 124 is attracted to the outer peripheral surface of the drying drum 176 by negative pressure and restrained so as to be in close contact with the recording medium. The recording medium 124 is dried by applying hot air from the hot air jet nozzle of the hot air drying means 182 to the recording medium 124 constrained by the drying drum 176 in this way.

  This prevents the occurrence of cockle. Further, by causing the recording medium 124 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 124 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 124 held on the drying drum 176 is evaporated, and drying processing 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, in the inkjet heads 172M, 172K, 172C, 172Y, the head meniscus portion is dried by thermal drying. Ink ejection failure 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 accelerated by heating from the back surface of the recording medium 124, 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 124 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. In addition, the recording medium 124 is held so that the recording surface 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. The occurrence of wrinkles and floats 124 can be prevented, and uneven drying due to these can be reliably prevented.

  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.

  In addition, 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 124. This is because if the aperture ratio is less than 1%, the expansion deformation of the recording medium 124 due to water absorption after recording cannot be sufficiently suppressed, and the drying drum 176 itself is also warmed. Drying is also promoted by contact, but if the aperture ratio exceeds 75%, the contact area between the back surface of the recording medium 124 and the outer peripheral surface of the drying drum 176 decreases, so that the recording medium 124 is held by suction. However, sufficient drying performance cannot be obtained, 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 124 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 far away, the effect of suppressing the deformation of the recording medium 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 124 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, so that the circumferential deformation and the axial deformation of the recording medium 124 are made uniform. You can also.

  Further, it is held on the outer peripheral surface of the drying drum 176 so that the recording surface of the recording medium 124 faces outward (that is, in a state where the recording surface of the recording medium 124 is curved so as to be convex), and is rotated and conveyed. While drying, it is possible to prevent the recording medium 124 from wrinkling and floating, and to reliably prevent drying unevenness due to these.

  Further, the drying drum 176 has means for providing a region in which the suction force is weaker than that of other portions in a part of the outer circumferential surface of the outer peripheral surface, and by using this, the recording medium 124 is stably stabilized. So as to be adsorbed to the drying drum 176. This will be described below.

  FIG. 4 shows an enlarged view of the second transfer drum transport means 128 and the drying drum 176.

  As described above, the drying drum 176 holds the recording medium 124 (not shown here) delivered from the second transfer drum transport unit 128 by the holding unit 177, and an arrow in the drawing from the suction hole that is not shown. As shown, the ambient air is sucked into the drum, and the recording medium 124 is dried by the hot air drying means 182 while being adsorbed to the outer peripheral surface of the drying drum 176 and rotated and conveyed.

  At this time, the drying drum 176 is provided with means for forming a region where the suction force is weaker than that of the other part over the entire width of the drum in a part of the circumferential direction. In the present embodiment, the means for forming a region where the suction force is weaker than other parts is constituted by a shielding means 183 that closes the suction hole formed in the outer peripheral surface of the drying drum 176 from the inside of the drum.

  The shielding means 183 is fixed in the drying drum 176 (for example, on its rotating shaft), and the tip surface formed at the tip thereof has a shape along the inner surface shape of the outer peripheral surface of the drying drum 176. The suction hole in the overlapping area is closed. Then, the recording medium 124 cannot be sucked from the suction hole closed by the tip surface, and a portion where the tip surface of the shielding unit 183 hits forms a region where the suction force is weaker than other portions.

  In the region where the suction force is weak, the suction of the recording medium 124 to the drying drum 176 is once released, so that the recording medium 124 slightly floats from the outer peripheral surface of the drying drum 176, and a space is formed. At this time, since the shielding means 183 is fixed, the area where the suction force is weak moves relative to the recording medium 124 toward the rear end side of the recording medium 124 as the drying drum 176 rotates, and finally the recording is performed. It exits from the rear end of the medium 124. Thereby, wrinkles generated on the recording medium 124 can be removed.

  Further, air is blown from the air blowing unit 180 on the downstream side of the region where the suction force is weak (in the rotation direction of the drying drum 176), so that the space formed between the recording medium 124 and the outer peripheral surface of the drying drum 176 can be more reliably obtained. The recording medium 124 is moved to the rear end side, and the recording medium 124 is wrinkled and smoothed.

  FIG. 5 is a plan view of the vicinity of the region where the suction force is weak from the outer peripheral surface side of the drying drum 176.

  In FIG. 5, the left-right direction is the width direction of the drying drum 176, and the arrow A direction is the drum rotation direction (recording medium conveyance direction). As shown in the figure, the front end surface 183a of the shielding means 183 has a wide open V shape, and the central portion of the recording medium 124 conveyed in the direction of the arrow A first hits an area where the suction force is weak, Subsequently, the rear end sides of both ends gradually come into contact with a region having a weak suction force.

  At this time, air is blown from the air blowing means 180 to the area B indicated by hatching in the drawing. Thereby, with respect to the space formed in the recording medium 124 (a space that becomes a ridge) in substantially the same shape as the V shape of the front end surface 183a of the shielding means 183, gradually from the center to both sides and the rear end side. Be blown. As a result, the space that becomes the wrinkle surely moves to the rear end side as the recording medium 124 is transported, and finally leaves the rear end of the recording medium 124 to remove the wrinkles.

  The shielding means 183 blocks the suction hole formed on the outer peripheral surface of the drying drum 176 by the front end surface 183a and blocks the suction force. The shielding means 183 is fixed, whereas the drying drum 176 Since it is rotating, there is a slight gap between the shielding means 183 and the inner surface (back surface) of the outer peripheral surface of the drying drum 176, and the suction hole is not completely blocked, but the suction hole is not completely closed. Even if there is no blockage, it is sufficient if the suction force can be weaker than other parts. The shielding means 183 moves the wrinkles of the recording medium 124 toward the region where the suction force is weak and relatively moves them, and finally expels them from the rear end side to remove the wrinkles.

  As shown in FIG. 5, the region where the suction force is weakened is formed on the front end surface 183 a of the shielding means 183, has the same width d over the entire width direction of the drying drum 176, and is formed in a V shape. The width d is preferably 10 mm to 200 mm. This is because if it is too narrow, it will break. On the other hand, if it is too wide, a suction failure occurs at the rear end of the recording medium, and the sheet floats. Although the width d depends on the size and thickness of the recording medium 124, the width d may be approximately about 25% of the length of the recording medium 124.

  Moreover, it is better that the V-shaped opening is not so narrow. For example, the value of the angle θ shown in FIG. 5 is preferably about 20 degrees or less.

  In the above embodiment, the suction hole is blocked by the shielding means 183 as means for weakening the suction force, but the means for weakening the suction force is not limited to this. For example, the suction force may be weakened by providing a shutter in the suction hole of the drying drum 176 and controlling the opening and closing of the shutter. In such a configuration, the suction force can be finely adjusted by changing the number of holes for closing the suction holes (the blockage rate per unit area).

  As another example of the means for weakening the suction force, for example, the suction area of the suction surface provided on the outer peripheral surface of the drying drum 176 is divided into a plurality of parts in the transport direction, and suction force generating means ( By arranging a flow path connected to a vacuum pump or the like, and controlling the suction force for each divided region at a predetermined timing, the suction force weak region moves as the drying drum 176 rotates. You can also. Hereinafter, this will be specifically described with reference to the drawings.

  FIG. 6 is an enlarged cross-sectional view showing a part of the outer peripheral surface portion of the drying drum 176. As shown in FIG. 6, the recording medium 124 is conveyed in the direction of arrow C in the figure with the leading end held by the holding means 177. At this time, a plurality of suction holes (not shown) are provided on the outer peripheral surface following the holding means 177 so as to suck and hold the recording medium 124 on the outer peripheral surface.

  Here, the suction area formed by the suction holes is divided into a plurality of areas in the transport direction, and the respective divided areas 179-1, 179-2, 179-3, 179-4, 179-5,. The force generating means (not shown) is connected to the flow path so that the suction force can be controlled for each divided region. For example, a valve is provided in the flow path of each divided area to control the suction flow rate or shut off the flow path itself.

  During suction conveyance, for example, at the timing t = t0, as shown in FIG. 6A, the suction force of the divided region 179-3 is weakened, and this divided region 179-3 is set as the weak suction force region W. Further, at the timing of t = t1 after t = t0, as shown in FIG. 6 (b), the suction force of the divided region 179-6 is weakened, and this is set as the weak suction force region W. Yes.

  In this way, the suction area on the outer peripheral surface of the drying drum 176 is divided into a plurality of divided areas in the transport direction, and areas where the suction power of each divided area is weakened as the drying drum 176 sucks and transports the recording medium 124. By making it move toward the conveyance upstream side in order, the same effect as the example shown above can be acquired.

  Each divided region is formed over the entire width direction of the drying drum 176, and the shape of each divided region is preferably V-shaped as shown in FIG.

  Further, the air blowing means 180 (smoothing means) provided on the upstream side of the hot air drying means 182 blows upstream of the area where the suction force is weakened by the shielding means 183, and becomes a trap of the recording medium 124. Although the space is moved relatively to the rear end side to remove the suction soot, this enables uniform drying and uniform suction. As described above, the air blowing unit 180 functions as a smoothing unit and an adsorption assisting unit. As described above, the suction assistance is performed by the non-contact air blowing means 180. If the suction assistance is performed by the contact means, undried ink is transferred to the contact means, resulting in an image defect. Because.

  For example, as shown in FIG. 5, the air blowing means 180 blows air obliquely toward the rear end side of the recording medium 124, applies it obliquely toward the end side in the width direction of the recording medium 124, and further at the rear end. Control the wind power to increase. As a result, the sheet is prevented from floating at the rear end of the recording medium 124, and the recording medium 124 is picked up by suction to enable uniform drying and uniform suction.

  Further, in the drying unit 118, a rectifying plate 181 may be provided so that the hot air of the hot air drying means 182 can be reused. A rectifying plate is formed so as to cover the hot air drying means 182 on the upper side thereof and so that the hot air blown out from the hot air drying means 182 is directed again to the drying drum 176 side. At this time, a guide plate is further provided on the downstream side of each hot air drying means 182 in the rotational direction of the drying drum 176, and the hot air blown out from each hot air drying means 182 once hits the surface of the drying drum 176 is directed again toward the drying drum 176. It is good to make it flow. By providing the current plate, it is possible to improve thermal efficiency and improve exhaust performance.

  Returning to FIG. 3 again, the recording medium 124 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 intermediate conveyance unit (third transfer cylinder conveyance unit) 130. It is.

  The recording medium 124 has its front end held by a holding claw (not shown) of the third transfer cylinder transfer unit 130 (transfer transfer unit), the recording surface faces inward, and the rear end side is in a free state. The side is conveyed along the guide member 131 so as to have a convex shape.

  That is, the third transfer drum transport unit 130 (passing transport unit) does not adsorb and restrain the recording medium 124, so that the drying unit 118 is sucked and restrained by the drying drum 176 and dried. The restraint of the recording medium 124 is once released, and the recording medium 124 is bent and corrected in the reverse direction, thereby flattening the recording medium 124 and preventing curling.

  Further, 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 124 facing the inner side during transport to the surface. The ejected ink is dried. Accordingly, it is possible to make uniform the drying unevenness caused by the suction holes of the drying drum 176 in the drying unit 118.

  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 receives the recording medium 124 from the third transfer drum conveying unit 130, the fixing drum 184 holds the leading end portion of the recording medium 124 by the holding unit 185 provided on the outer peripheral surface of the fixing drum 184, thereby holding the recording medium 124 on the outer peripheral surface. Wrap around and transport. The fixing drum 184 does not have a suction hole that sucks the recording medium 124.

  The recording medium 124 wound around the outer peripheral surface of the fixing drum 184 and conveyed is pressed by a pressing roller (smoothing means) 188 disposed facing 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 124 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 124 with the pressing 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 124 is leveled, and glossiness is obtained.

  Next, the recording medium 124 is cured and fixed by being irradiated with ultraviolet rays from an ultraviolet light source 190 disposed opposite to the fixing drum 184. Here, a plurality of ultraviolet light sources 190 may be provided as shown in FIG. Accordingly, by reducing the irradiation intensity of each ultraviolet light source 190, it becomes possible to increase the curing conditions with the irradiation time, and it is possible to reduce the cost and reduce the heat generation amount of the ultraviolet light source 190.

  The ultraviolet light source 190 is not particularly limited, and for example, a metal halide lamp, a high-pressure mercury lamp, a black light, a cold cathode tube, a UV-LED, or the like is preferably used.

The peak wavelength of ultraviolet rays irradiated by the ultraviolet light source 190 is preferably 200 to 600 nm, more preferably 300 to 450 nm, and still more preferably 350 to 450 nm, although it depends on the absorption characteristics of the ink composition.
The irradiation energy of the ultraviolet light source 190, preferably 2000 mJ / cm ² or less, more preferably from 10 to 2000 mJ / cm ^2, more preferably from 20~1000mJ / cm ^2, particularly preferably 50 to 800 mJ / Cm ² .
In the ink jet recording apparatus of the present invention, it is appropriate to irradiate the recording surface of the recording medium with ultraviolet rays for 0.01 to 10 seconds, more preferably for 0.1 to 2 seconds.

  Note that the surface temperature of the fixing drum 184 may be set to 50 ° C. or more, for example, and the recording medium 124 held on the outer peripheral surface of the fixing drum 184 may be heated from the back surface. Thereby, drying of the recording medium 124 is promoted, image destruction at the time of fixing can be prevented, and image intensity can be increased by an effect of increasing the image temperature.

  As described above, in the present embodiment, an area for once releasing the adsorption force of the recording medium adsorbed on the drying drum is provided, and after forming a space for gathering wrinkles in this part, the adsorption force is increased again. By moving the space relative to the recording medium and moving it away from the rear end side of the recording medium, it is possible to remove wrinkles and enable uniform suction.

  In the embodiment described above, the processing liquid drum 154, the drawing drum 170, and the drying drum 176 suck the recording medium 124 through the suction holes and suck them onto each drum, but the suction method is suction. The present invention is not limited, and for example, the present invention can be applied to electrostatic adsorption.

  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 ... Intermediate conveyance part (1st transfer cylinder conveyance) Means), 128... Intermediate conveyance section (second transfer cylinder conveyance means), 130... Intermediate conveyance section (third transfer cylinder conveyance means), 154... Processing liquid drum, 156. DESCRIPTION OF SYMBOLS ... Drying drum, 178 ... Solvent drying apparatus, 180 ... Air blowing means, 182 ... Hot air drying means, 183 ... Shielding means, 184 ... Fixing drum, 190 ... Ultraviolet light source, 192 ... Paper discharge unit

Claims (13)

An inkjet head that ejects ink toward a recording medium;
A holding means for holding the leading end of the recording medium provided on the outer peripheral surface; and an adsorbing means for sucking the recording medium to the outer peripheral surface, and holding the leading end of the recording medium with the holding means and A drum for adsorbing and rotating the recording medium to the outer peripheral surface;
A part of the outer peripheral surface of the drum in the circumferential direction has a weak suction force region where the suction force of the recording medium is weaker than the other part only over the entire width of the drum. A weakly attracting force region forming means for moving relative to the recording medium that is sucked and conveyed by the surface;
A blower unit that is disposed to face the outer peripheral surface of the drum and blows air to the recording medium from the outside of the outer peripheral surface on the downstream side in the transport direction of the recording medium in the weak suction force region,
An ink jet recording apparatus comprising:   The drum is a drawing drum in which the inkjet head is disposed opposite to an outer peripheral surface of the drum, and ink is ejected from the inkjet head onto the recording medium adsorbed on the outer peripheral surface. The ink jet recording apparatus according to claim 1.   The drum is configured to suck and convey the recording medium on which the ink has been ejected to the outer peripheral surface, and to dry the recording medium by hot air drying means disposed to face the outer peripheral surface. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is a drum. An ink jet recording apparatus according to claim 3, the hot air drying means and also be used as the blowing means. The blowing means, an ink jet recording apparatus according to claim 1, characterized in that the blowing diagonally toward the rear end side of the recording medium. The suction means is a suction means for sucking the recording medium to the outer peripheral surface by sucking air from a suction hole formed in the outer peripheral surface, and the suction force weak region forming means is formed on the outer peripheral surface. The suction area formed by arranging the suction holes is divided into a plurality of areas in the recording medium conveyance direction, each divided area is connected to a suction force generating means, and the suction force is controlled for each divided area. an ink jet recording apparatus according to any one of claims 1 to 5, characterized in that the. An inkjet head that ejects ink toward a recording medium;
A holding means for holding the leading end of the recording medium provided on the outer peripheral surface; and an adsorbing means for sucking the recording medium to the outer peripheral surface, and holding the leading end of the recording medium with the holding means and A drum for adsorbing and rotating the recording medium to the outer peripheral surface;
A part of the outer peripheral surface of the drum in the circumferential direction has a weak suction force region where the suction force of the recording medium is weaker than the other part only over the entire width of the drum. A weakly attracting force region forming means for moving relative to the recording medium that is sucked and conveyed by the surface;
With
The suction means is a suction means for sucking the recording medium to the outer peripheral surface by sucking air from a suction hole formed on the outer peripheral surface, and the suction force weak region forming means is disposed in the drum. A suction hole shielding means for closing the suction hole provided fixedly;
The suction hole shielding means is a belt-like shape formed in a belt shape having substantially the same width over the entire width of the outer peripheral surface and opened toward the downstream side in the transport direction with the central portion in the width direction of the outer peripheral surface serving as a vertex. of members, said to contact substantially along the rear surface side of the outer peripheral surface, wherein the to Louis inkjet recording apparatus that has been constructed is fixed so as not to rotate together with the drum. An inkjet head that ejects ink toward a recording medium;
A holding means for holding the leading end of the recording medium provided on the outer peripheral surface; and an adsorbing means for sucking the recording medium to the outer peripheral surface, and holding the leading end of the recording medium with the holding means and A drum for adsorbing and rotating the recording medium to the outer peripheral surface;
A part of the outer peripheral surface of the drum in the circumferential direction has a weak suction force region where the suction force of the recording medium is weaker than the other part only over the entire width of the drum. A weakly attracting force region forming means for moving relative to the recording medium that is sucked and conveyed by the surface;
With
The suction means is a suction means for sucking the recording medium to the outer peripheral surface by sucking air from a suction hole formed on the outer peripheral surface, and the suction force weak region forming means is disposed in the drum. A suction hole shielding means for closing the suction hole provided fixedly;
The suction hole shielding means is a plate having a belt-like shape having substantially the same width over the entire width of the outer peripheral surface and a smooth concave shape opened toward the downstream side in the transport direction with the central portion in the width direction of the outer peripheral surface serving as a vertex. Jo of members, said to contact substantially along the rear surface side of the outer peripheral surface, wherein the to Louis inkjet recording apparatus that has been constructed is fixed so as not to rotate together with the drum. The drum is a drawing drum in which the inkjet head is disposed opposite to an outer peripheral surface of the drum, and ink is ejected from the inkjet head onto the recording medium adsorbed on the outer peripheral surface. An ink jet recording apparatus according to claim 7 or 8 . The drum is configured to suck and convey the recording medium on which the ink has been ejected to the outer peripheral surface, and to dry the recording medium by hot air drying means disposed to face the outer peripheral surface. 9. The ink jet recording apparatus according to claim 7 , wherein the ink jet recording apparatus is a drum. The recording medium on which ink is ejected from the inkjet head is held at the tip by holding means provided on the outer peripheral surface of the drum, and is adsorbed to the outer peripheral surface of the drum by the adsorbing means and conveyed.
Rotation of the drum is performed on a part of the outer circumferential surface of the drum that extends across the entire width of the drum, and that part of the drum is weaker in suction force than the other part. And formed so as to move relative to the recording medium that is attracted to the outer peripheral surface and conveyed.
The recording medium that is attracted to and transported by the outer peripheral surface of the drum is temporarily released in the region where the suction force is weak, and a space is formed between the recording medium and the outer peripheral surface. Thereafter, the suction force is increased again after passing through the weak suction force region, so that the formed space moves to the rear end side of the recording medium.   12. The ink jet recording method according to claim 11, wherein air is blown to the recording medium from the outside of the outer peripheral surface on the downstream side in the conveyance direction of the recording medium in the weak adsorption force region. The suction means is a suction means for sucking the recording medium to the outer peripheral surface by sucking air from a suction hole formed in the outer peripheral surface;
The suction force weak region is formed by closing the suction hole by suction hole shielding means fixed so as not to rotate together with the drum in the drum. The inkjet recording method according to 11 or 12.

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