JP2010082936A - Printer - Google Patents

Abstract

Provided is a printing apparatus capable of efficiently drying printed matter with power saving and maintaining stable quality.
A sheet-like recording medium 14 that is inkjet-recorded by a printing unit is transferred to a pressure drum 306 of a solvent drying unit 30 through a transfer drum 304. The impression cylinder 306 is heated by a heating unit 308 installed around the impression cylinder 306, and the recording medium 14 is instantaneously heated by being placed on the surface (conveying surface) of the heated impression cylinder 308. Is done. A blower unit 310 is installed around the pressure drum 308, and normal temperature wind is blown toward the recording medium 14 to be conveyed. As a result, water contained in the ink can be efficiently blown off, and the image quality performance can be greatly improved. In addition, since the air is blown at room temperature, power consumption can be suppressed, and operation can be performed with energy saving.
[Selection] Figure 10

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus that uses water-based ink to print on general-purpose printing paper by an inkjet method.

  In a printing apparatus that uses water-based ink to print on general-purpose printing paper by an inkjet method, it is necessary to dry the printing surface in order to form a high-quality image.

  Patent Document 1 proposes that in a printing apparatus that performs printing by an ink jet system, hot paper is blown with a blower and dried while adsorbing and holding the continuous paper after printing by suction and heating with a heated bed.

Patent Document 2 proposes that a gravure printing machine is dried by spraying hot air on the surface while bringing a cooled guide roller into contact with the back surface of the recording medium after printing and cooling.
JP 2004-330568 A JP 2005-343005 A

  However, the method of Patent Document 1 has a drawback that when a large amount of printed matter is processed at a high speed, a large amount of heat is generated in the apparatus, and the temperature in the apparatus becomes unstable. As a result, there is a drawback that the quality of the printed matter becomes unstable. Moreover, since hot air is blown with a blower while heating a bed, there exists a fault that an apparatus consumes a lot of electric power.

  In the method of Patent Document 2, the drying efficiency is lowered when the temperature of the recording medium is low. Therefore, when a large amount of printed matter is processed at high speed, it is necessary to supply high-temperature and high-speed hot air, and a large amount of heat is generated. There is a disadvantage that it occurs. As a result, there is a drawback that the quality of the printed matter becomes unstable. Moreover, since it becomes necessary to supply hot air of high temperature and high speed, there is a drawback that the apparatus consumes a large amount of power.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a printing apparatus capable of efficiently drying printed matter with power saving and maintaining stable quality.

  In order to achieve the above object, the invention according to claim 1 is a printing apparatus including a drying unit that dries a sheet-like recording medium immediately after printing, wherein the drying unit is provided on a rotating endless conveying surface. The recording medium is placed on the recording medium, the conveying means for conveying the recording medium along a predetermined conveying path, the heating means for heating the conveying surface of the conveying means, and the recording medium conveyed by the conveying means at room temperature. And a blowing means for blowing the air.

  According to the present invention, a sheet-like recording medium immediately after printing is placed and conveyed on a rotating endless conveyance surface (for example, a roller (cylinder) or a conveyor). The conveying surface is heated by a heating unit, and the recording medium after printing is instantaneously heated by being placed on the heated conveying surface. Along with the heating by the conveying surface, the recording medium is blown at normal temperature from the blowing means during the conveying process by the conveying surface. Thereby, the water contained in the ink can be efficiently blown off, and the image quality performance can be greatly improved. In addition, since the air is blown at room temperature, power consumption can be suppressed, and operation can be performed with energy saving.

  The invention according to claim 2 is characterized in that, in order to achieve the above object, the heating means is constituted by a direct heating means that directly heats a heat source in contact with the inside of the transport surface. A printing apparatus according to claim 1 is provided.

  According to this invention, a heating means is comprised with the direct heating means which makes a heat source contact the inner side of a conveyance surface, and heats it directly. By directly heating the conveyance surface, the conveyance surface can be efficiently heated.

  According to a third aspect of the present invention, in order to achieve the above object, the heating unit irradiates heat to the conveying surface, and a direct heating unit that directly heats the heating surface by contacting a heat source inside the conveying surface. The printing apparatus according to claim 1, further comprising: an indirect heating means for indirectly heating.

  According to the present invention, the heating unit includes a direct heating unit that directly heats the heat source in contact with the inside of the transport surface, and an indirect heating unit that heats the transport surface indirectly by heating. Composed. Thereby, the conveyance surface can be efficiently heated without unevenness.

  The invention according to claim 4 is characterized in that, in order to achieve the above object, the heating means is configured by indirect heating means for indirect heating by irradiating the transport surface with heat. A printing apparatus according to 1 is provided.

  According to this invention, a heating means is comprised with the indirect heating means which irradiates heat to a conveyance surface and heats indirectly. Thereby, a conveyance surface can be heated evenly.

  The invention according to claim 5 is characterized in that, in order to achieve the object, the indirect heating means irradiates the transport surface with heat on the transport path of the recording medium. Providing equipment.

  According to the present invention, the indirect heating means irradiates the transport surface with heat on the transport path of the recording medium to heat the transport surface. Thereby, the recording medium can be passed through the heat irradiation area by the indirect heating means, and the recording medium can be dried by using the heat irradiated from the indirect heating means.

  The invention according to claim 6 is characterized in that, in order to achieve the object, the indirect heating means irradiates heat to the transport surface other than the transport path of the recording medium. Providing equipment.

  According to the present invention, the indirect heating means irradiates the transport surface with heat outside the recording medium transport path to heat the transport surface. Thereby, only a conveyance surface can be heated and a conveyance surface can be efficiently heated without unevenness.

  In order to achieve the above object, the indirect heating means includes: a first indirect heating means for irradiating heat to the transport surface on a transport path of the recording medium; and 5. The printing apparatus according to claim 3, further comprising: a second indirect heating unit configured to irradiate heat on the transport surface other than the transport path.

  According to the present invention, the indirect heating unit irradiates heat to the conveyance surface on the conveyance path of the recording medium, and the second indirect heating unit irradiates heat to the conveyance surface other than the conveyance path of the recording medium. It consists of indirect heating means. Accordingly, the conveyance surface can be efficiently heated without unevenness, and the recording medium can be dried using heat from the indirect heating means.

  In the invention according to claim 8, in order to achieve the object, the heating means heats the conveying surface to 40 ° C. to 70 ° C., and the blowing means blows air at a speed of 20 m / s or less. A printing apparatus according to any one of claims 1 to 7 is provided.

  According to this invention, a heating means heats a conveyance surface to 40 to 70 degreeC, and a ventilation means ventilates normal temperature wind at a speed | rate of 20 m / s or less. By operating in this range, the printed matter can be efficiently dried with power saving.

  The invention according to claim 9 provides the printing apparatus according to any one of claims 1 to 8, wherein the recording medium is general-purpose printing paper in order to achieve the object.

  According to the present invention, the recording medium is composed of general-purpose printing paper. Since the general-purpose printing paper easily bleeds ink, the present invention can be particularly effectively operated.

  According to the present invention, printed matter can be efficiently dried with power saving, and can be maintained in stable quality.

  Hereinafter, preferred embodiments of a printing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

[Entire device configuration]
FIG. 1 is an overall configuration diagram showing an embodiment of a printing apparatus according to the present invention.

  The printing apparatus 10 shown in FIG. 1 is a printing apparatus that prints on a sheet-like recording medium (in this embodiment, in particular, general-purpose printing paper) by an inkjet method, and mainly includes a paper feeding unit 22 that supplies the recording medium 14. A permeation suppression processing unit 24 that performs permeation suppression processing on the recording medium 14, a treatment liquid application unit 26 that applies a processing liquid such as an ink flocculant to the recording medium 14, and color ink is applied to the recording medium 14 A printing unit 28 that performs image formation, a solvent drying unit 30 that dries the recording medium after printing, a hot-pressure fixing unit 32 that fastens the image, and a discharge that conveys and discharges the recording medium 14 on which the image is formed. Part 34.

<Paper Feeder>
The paper supply unit 22 is provided with a paper supply tray 36 for supplying the recording medium 14 in the form of a sheet. The recording medium 14 is fed from the paper feed tray 36 by the adhesive roller 37 and fed to the permeation suppression processing unit 24.

<Osmosis suppression processing section>
The permeation suppression processing unit 24 performs permeation suppression processing on the recording medium 14.

  A transfer drum 38 is provided between the paper feed tray 36 and the pressure drum 40 of the permeation suppression processing unit 24, and the recording medium 14 fed from the paper feed tray 36 passes through this transfer drum 38. It is delivered to the impression cylinder 40 of the permeation suppression processing unit 24. The impression cylinder 40 is provided with a gripper (not shown). The recording medium 14 rotates together with the impression cylinder 40 by being gripped by the gripper.

  Around the pressure drum 40 of the permeation suppression processing unit 24, a liquid application device 42, a paper presser 44, and a permeation suppression agent drying unit 46 are sequentially arranged from the upstream side in the rotation direction of the pressure drum 40 (counterclockwise direction in FIG. 1). Has been placed.

  The liquid application device 42 selectively applies a permeation inhibitor to a desired area of the recording medium 14 that is held by the impression cylinder 40 and rotates.

  The sheet presser 44 feeds the recording medium 14 in the rotational direction of the impression cylinder 40 while pressing both ends and the rear end of the recording medium 14 fed to the peripheral surface of the impression cylinder 40.

  The permeation suppression agent drying unit 46 includes a heater and a fan. The permeation suppression agent is pre-dried by blowing hot air onto the recording medium 14 held and rotated by the impression cylinder 40.

<Processing liquid application part>
The treatment liquid application unit 26 applies a treatment liquid such as an ink flocculant to the recording medium 14.

  A transfer drum 84 is provided between the pressure drum 40 of the permeation suppression processing unit 24 and the pressure drum 86 of the treatment liquid application unit 26, and the recording medium 14 subjected to the permeation suppression processing by the permeation suppression processing unit 24 is Then, the pressure is transferred to the pressure drum 86 of the treatment liquid application unit 26 through the transfer drum 84.

  Here, first, the configuration of the transfer drum 84 will be described. The transfer cylinder 84 is formed in a drum shape, and grippers (not shown) are attached at two locations (symmetric positions) on the peripheral surface thereof. The recording medium 14 is held by the gripper and conveyed. In addition, a heater (not shown) (for example, a halogen heater, an infrared heater, etc.) is attached inside the transfer cylinder 84, and the recording medium 14 conveyed by the transfer cylinder 84 is heated by heat radiated from the heater. It is conveyed while being heated.

  The transfer drum 84 is configured as described above. The recording medium 14 transferred from the impression cylinder 40 of the permeation suppression processing unit 24 to the transfer cylinder 84 is heated and dried by the radiant heat of the heater built in the transfer cylinder 84 during the conveyance process. Then, it is delivered to the impression cylinder 86 of the treatment liquid application unit 26.

  The pressure drum 86 of the treatment liquid application unit 26 is formed in a drum shape, and grippers (not shown) are attached to two places (symmetric positions) on the peripheral surface. The recording medium 14 is held by the gripper and conveyed.

  Around the pressure drum 86, a processing liquid head 202 and a processing liquid drying unit 204 are provided in order from the upstream side in the rotation direction of the pressure cylinder 86 (counterclockwise direction in FIG. 1).

  The treatment liquid head 202 ejects treatment liquid onto the recording medium 14 held by the impression cylinder 86, and the same configuration as each ink head disposed in the printing unit 28 is applied. However, the nozzle shape, surface treatment, drive waveform, and the like are adjusted according to the viscosity, surface tension, pH (hydrogen ion concentration), etc. of the treatment liquid (aggregation treatment agent).

  About the process liquid drying unit 204, the structure similar to the penetration inhibitor drying unit 46 of the penetration suppression process part 24 mentioned above is applied. That is, the processing liquid is pre-dried by blowing hot air onto the recording medium 14 that is configured to include a heater and a fan and is held by the impression cylinder 86 and moves.

  Note that the treatment liquid such as an aggregating agent used in the printing apparatus 10 of the present embodiment is preferably an acidic liquid having an action of aggregating the color material contained in the ink used in the subsequent printing unit 28. Specifically, a treatment liquid to which an acid such as 2-pyrrolidone-5-carboxylic acid, phosphoric acid, succinic acid or citric acid is added can be considered.

  In addition, it is also possible to make the permeation suppression layer unnecessary by adding a small amount of a high boiling point solvent such as glycerin or polymer particles to suppress the permeation of the treatment liquid. When the treatment liquid having such a permeation suppression effect is applied by the liquid application device 42, the pressure drum 86, the treatment liquid head 202, the treatment liquid drying unit 204, and the like of the treatment liquid application unit 26 are not necessary.

<Printing section>
The printing unit 28 forms an image by applying color ink to the recording medium 14.

  A transfer drum 214 is provided between the pressure drum 86 of the treatment liquid application unit 26 and the pressure drum 216 of the printing unit 28, and a recording medium in which an aggregation treatment agent layer is formed on the printing surface by the treatment liquid application unit 26. 14 is transferred to the impression cylinder 216 of the printing unit 28 via the transfer cylinder 214. The impression cylinder 216 is provided with a gripper (not shown). The recording medium 14 rotates together with the impression cylinder 216 by being gripped by the gripper.

  The configuration of the transfer drum 214 is the same as the configuration of the transfer drum 84 of the permeation suppression processing unit 24 described above. That is, the recording medium 14 is conveyed by gripping the recording medium 14 with a gripper provided on the peripheral surface with a built-in heater. The recording medium 14 is heated by the heat radiated from the transfer drum 214 during the conveyance process.

  Around the impression cylinder 216 of the printing unit 28, black (K), cyan (C), magenta (M), yellow (Y (Y) in order from the upstream side in the rotation direction (counterclockwise direction in FIG. 1) of the impression cylinder 216. Ink heads 210K, 210C, 210M, and 210Y corresponding to the four color inks are provided.

  As each of the ink heads 210K, 210C, 210M, and 210Y, an ink jet type recording head (ink jet head) is applied. Each of the ink heads 210K, 210C, 210M, and 210Y discharges the corresponding color ink droplets toward the recording medium 14 held in a state of negative pressure adsorption or electrostatic adsorption on the pressure drum 216.

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

  Here, the structure of each head will be described. Since the structures of the color-specific heads 210K, 210C, 210M, and 210Y are the same, the head is represented by the reference numeral 210 as a representative of them. The processing liquid head 202 used in the processing liquid application unit 26 also has the same structure as the ink head 210.

  2A is a plan perspective view showing an example of the structure of the ink head 210, and FIG. 2B is an enlarged view of a part thereof.

  In order to increase the dot pitch printed on the recording medium 14, it is necessary to increase the nozzle pitch in the ink head 210. As shown in FIGS. 2A and 2B, the ink head 210 of this example includes a plurality of ink chamber units (nozzles 281 that are ink ejection ports, pressure chambers 282 corresponding to the nozzles 281, etc.). It has a structure in which droplet ejection elements 283 as recording element units are arranged in a zigzag matrix (two-dimensionally), thereby arranging them in the longitudinal direction of the head (direction perpendicular to the paper transport direction). Thus, the density of the substantial nozzle interval (projection nozzle pitch) projected is increased.

  A form in which one or more nozzle rows are formed in a direction corresponding to the entire width of the image forming region in a direction (arrow M in FIG. 2) substantially orthogonal to the conveyance direction of the recording medium 14 (arrow S in FIG. 2) is illustrated. It is not limited to examples. For example, instead of the configuration of FIG. 2 (a), as shown in FIG. 3, a long head module 280 ′ in which a plurality of nozzles 281 are two-dimensionally arranged is arranged in a staggered manner and connected to each other. Therefore, a line head having a nozzle row having a length corresponding to the entire width of the image forming area of the recording medium 14 as a whole may be configured.

  The pressure chamber 282 provided corresponding to each nozzle 281 has a substantially square planar shape (see FIGS. 2 (a) and 2 (b)), and the nozzle 281 is located at one of the diagonal corners. An outlet for supplying ink (supply port) 284 is provided on the other side. Note that the shape of the pressure chamber 282 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, and an ellipse.

  4 is a cross-sectional view showing a three-dimensional configuration of one channel of droplet discharge elements (ink chamber unit corresponding to one nozzle 281) serving as a recording element unit in the ink head 210 (the line BB in FIG. 2). FIG.

  As shown in FIG. 4, each pressure chamber 282 is in communication with a common channel 285 through a supply port 284. The common channel 285 communicates with an ink tank (not shown) that is an ink supply source, and the ink supplied from the ink tank is supplied to each pressure chamber 282 via the common channel 285.

  An actuator 288 provided with an individual electrode 287 is joined to a pressure plate (vibrating plate also used as a common electrode) 286 constituting a part of the pressure chamber 282 (the top surface in FIG. 4). By applying a drive voltage between the individual electrode 287 and the common electrode, the actuator 288 is deformed to change the volume of the pressure chamber 282, and ink is ejected from the nozzle 281 due to the pressure change accompanying this. When the displacement of the actuator 288 returns to the original state after ink ejection, new ink is refilled into the pressure chamber 282 from the common channel 285 through the supply port 284.

  For the actuator 288, a piezoelectric element using a piezoelectric body such as lead zirconate titanate or barium titanate is preferably used.

  By controlling the drive of the actuator 288 corresponding to each nozzle 281 according to dot data generated from the input image by digital halftoning processing, ink droplets can be ejected from the nozzle 281. A desired image can be recorded on the recording medium 14 by controlling the ink ejection timing of each nozzle 281 in accordance with the conveying speed while conveying the recording medium 14 in the sub-scanning direction at a constant speed.

  As shown in FIG. 5, the ink chamber unit 283 having the structure described above has a constant arrangement pattern along the row direction along the main scanning direction and the oblique column direction having a constant angle θ that is not orthogonal to the main scanning direction. Thus, the high-density nozzle head of this example is realized by arranging a large number in a grid pattern.

  That is, the pitch PN of the nozzles projected (orthographically projected) to be aligned in the main scanning direction by a structure in which a plurality of ink chamber units 283 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction. D × cos θ, and in the main scanning direction, each nozzle 281 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a substantial increase in the density of nozzle rows projected so as to be aligned in the main scanning direction.

  When driving a nozzle with a full line head having a nozzle row having a length corresponding to the entire printable width, (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially moved from one side to the other. (3) The nozzles are divided into blocks, and each block is sequentially driven from one side to the other, and so on. One line (1 in the width direction of the recording medium 14 (direction perpendicular to the transport direction)) The driving of the nozzle that prints a line of dots in a row or a line consisting of dots in a plurality of rows is defined as main scanning.

  In particular, when driving the nozzles 281 arranged in a matrix as shown in FIG. 5, the main scanning as described in the above (3) is preferable. That is, nozzles 281-11, 281-12, 281-13, 281-14, 281-15, 281-16 are made into one block (other nozzles 281-21,..., 281-26 are made into one block, .., 281-36 as one block,..., And the nozzles 281-11, 281-12,. One line is printed in the width direction of 14.

  On the other hand, by moving the full line head and the recording medium 14 relative to each other, printing of one line (a line formed by a single line of dots or a line composed of a plurality of lines) is repeatedly performed. This is defined as sub-scanning.

  The direction indicated by one line (or the longitudinal direction of the belt-like region) recorded by the main scanning is referred to as a main scanning direction, and the direction in which the sub scanning is performed is referred to as a sub scanning direction. That is, in the present embodiment, the conveyance direction of the recording medium 14 is the sub-scanning direction, and the direction orthogonal to the recording medium 14 is the main scanning direction. In implementing the present invention, the nozzle arrangement structure is not limited to the illustrated example.

  In this embodiment, a method of ejecting ink droplets by deformation of an actuator 88 typified by a piezo element (piezoelectric element) is adopted. However, the method of ejecting ink is not particularly limited in implementing the present invention. Instead of the piezo jet method, various methods such as a thermal jet method in which ink is heated by a heating element such as a heater to generate bubbles and ink droplets are ejected by the pressure can be applied.

<Solvent drying part>
The solvent drying unit 30 dries the recording medium 14 after printing.

  A transfer drum 304 is provided between the pressure drum 216 of the printing unit 28 and the pressure drum 306 of the solvent drying unit 30. The recording medium 14 to which each color ink is applied by the printing unit 28 is the transfer drum 304. Is transferred to the impression cylinder 306 of the solvent drying unit 30. The impression cylinder 306 is provided with a gripper (not shown), and the recording medium 14 rotates together with the impression cylinder 306 by being gripped by the gripper.

  The configuration of the transfer drum 304 is the same as the configuration of the transfer drum 84 of the permeation suppression processing unit 24 described above. That is, the recording medium 14 is conveyed by gripping the recording medium 14 with a gripper provided on the peripheral surface with a built-in heater. The recording medium 14 is heated by the heat radiated from the transfer drum 304 during the conveyance process.

  Around the pressure drum 306, a heating unit 308 and a blower unit 310 are provided in order from the upstream side in the rotation direction of the pressure drum 306.

  The heating unit 308 is composed of, for example, an infrared heater, and is disposed to face the surface of the impression cylinder 306. The heating unit 308 indirectly heats the surface (conveying surface) of the impression cylinder 306 by irradiating the surface of the impression cylinder 306 with heat.

  The blower unit 310 is constituted by, for example, a blower that blows air at room temperature, and is disposed to face the surface of the impression cylinder 306. The blower unit 310 blows air at normal temperature onto the recording medium 14 that is held by the pressure drum 306 and rotates.

  The recording medium 14 transferred from the transfer cylinder 304 to the impression cylinder 306 is instantaneously heated by coming into contact with the heated surface (conveying surface) of the impression cylinder 306. By passing through the blower unit 310 while the temperature of the recording medium 14 is in contact, moisture contained in the ink in the image formed by the printing unit 28 can be efficiently blown off, and the image quality performance is greatly improved. Can be made.

  The configuration and operation of the solvent drying unit 30 will be described in detail later.

<Hot pressure fixing part>
The heat and pressure fixing unit 32 makes the image robust.

  A transfer drum 324 is provided between the pressure drum 306 of the solvent drying unit 30 and the pressure drum 326 of the heat and pressure fixing unit 32, and the recording medium 14 from which the water content of the ink has been removed by the solvent drying unit 30 is as follows. This is transferred to the pressure drum 326 of the hot-pressure fixing unit 32 via the transfer drum 324. The impression cylinder 326 is provided with a gripper (not shown), and the recording medium 14 rotates together with the impression cylinder 326 by being gripped by the gripper.

  A heat roller (fixing roller) adjusted to a predetermined temperature (for example, 60 to 120 ° C.) is opposed to the pressure drum 326 adjusted to a predetermined temperature (for example, 40 to 80 ° C.). 328a, 328b, and 328c are provided.

  The heat rollers 328a, 328b, and 328c are preferably those in which a surface such as rubber is coated with a liquid repellent material such as PFA or fluorine-based elastomer, or a hard material that is subjected to a treatment such as hard chrome plating. Further, a cleaning unit 329 having a release agent application function is in contact with the heat rollers 328a, 328b, and 328c. As a release agent, in addition to general release silicone oil, a high-boiling solvent having paper permeability may be used, and the coating thickness is preferably 30 nm to 1 μm from the viewpoint of release properties and glossiness. .

  The transfer drum 324 is provided with a stamp-type member 325 using a winding-type non-woven fabric, and the stamp-type member 325 cannot penetrate into the recording medium 14 during conveyance of the impression drum 306 and the transfer drum 324. Absorbs high boiling solvents.

  The configuration of the transfer drum 324 is the same as the configuration of the transfer drum 84 of the permeation suppression processing unit 24 described above. That is, the recording medium 14 is conveyed by gripping the recording medium 14 with a gripper provided on the peripheral surface with a built-in heater. The recording medium 14 is heated by the heat radiated from the transfer drum 324 in the conveyance process.

  The recording medium 14 transferred to the pressure drum 326 via the transfer drum 324 is heated and pressed by the heat rollers 328a, 328b, and 328c, whereby latex particles added to the ink are formed into a film. The image formed on the recording medium 14 is fastened and fixed on the recording medium 14.

<Discharge unit>
The discharge unit 34 conveys and discharges the recording medium 14 on which an image is formed.

  A transfer drum 344 is provided between the pressure drum 326 of the hot-pressure fixing unit 32 and the discharge tray 346 of the discharge unit 34, and the recording medium 14 with the image fastened by the hot-pressure fixing unit 32 is the recording medium 14. The paper is transferred to the discharge tray 346 via the transfer drum 344 and discharged outside the apparatus.

  The transfer drum 344 is heated by a heating means (not shown), and further promotes the penetration of the high boiling point solvent and corrects the curl of the recording medium 14.

  Further, the discharge unit 34 includes an image sensor such as a CCD for measuring a check pattern of the recording medium 14, a moisture content, a surface temperature, a glossiness, and an in-line sensor 348 such as an infrared thermometer, an infrared moisture meter, and a gloss meter. Is arranged. As described above, the optical density and dot diameter of the patch are measured by the inline sensor 348 to control the coating amount of the aggregating agent, the color registration is corrected by measuring the pattern of each color, the leading edge and the width direction. The pattern is measured to correct the magnification, and the fixing temperature is adjusted in real time from the surface temperature, so that the quality such as gloss, density, magnification, image distortion and displacement is kept stable.

<Control system>
FIG. 6 is a principal block diagram showing the system configuration of the printing apparatus 10 according to the present embodiment.

  The printing apparatus 10 includes a communication interface 470, a system controller 472, a memory 474, a ROM 475, a motor driver 476, a heater driver 478, a print control unit 480, an image buffer memory 482, a head driver 484, and the like.

  The communication interface 470 is an interface unit that receives image data sent from the host computer 486. As the communication interface 470, 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 (not shown) for speeding up communication may be mounted. The image data sent from the host computer 486 is taken into the printing apparatus 10 via the communication interface 470 and temporarily stored in the memory 474.

  The memory 474 is a storage unit that temporarily stores an image input via the communication interface 470, and data is read and written through the system controller 472. The memory 474 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 472 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire printing apparatus 10 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. That is, the system controller 472 controls each part such as the communication interface 470, the memory 474, the motor driver 476, the heater driver 478, etc., performs communication control with the host computer 486, read / write control of the memory 474, etc. Control signals for controlling the motor 488 and the heater 489 are generated.

  The ROM 475 stores programs executed by the CPU of the system controller 472 and various data necessary for control. The ROM 475 may be a non-rewritable storage unit, or may be a rewritable storage unit such as an EEPROM. The memory 474 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 476 is a driver that drives the motor 488 in accordance with an instruction from the system controller 472. In FIG. 6, the motors arranged at the respective parts in the apparatus are represented by reference numeral 488. The motor 488 is a motor that drives the pressure cylinders 40, 86, 216, 306, 326, the transfer cylinders 84, 214, 304, 324, 344, the sheet press 44, the heat rollers 328a, 328b, 328c described in FIG. It is included.

  The heater driver 478 is a driver that drives the heater 489 in accordance with an instruction from the system controller 472. In FIG. 5, a plurality of heaters provided in the printing apparatus 10 are represented by reference numeral 489. The heater 489 includes a permeation suppressor drying unit 46, a heater for the treatment liquid drying unit 204, and the like.

  The print control unit 480 has a signal processing function for performing various processing and correction processing for generating a print control signal from the image data in the memory 474 according to the control of the system controller 472, and the generated print This is a control unit that supplies data (dot data) to the head driver 484. Necessary signal processing is performed in the print control unit 480, and the ejection amount and ejection timing of the ink droplets of the ink head 210 are controlled via the head driver 484 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 480 includes an image buffer memory 482, and image data, parameters, and other data are temporarily stored in the image buffer memory 482 when image data is processed in the print control unit 480. In FIG. 28, the image buffer memory 482 is shown in a mode associated with the print control unit 480, but can also be used as the memory 474. Also possible is an aspect in which the print control unit 480 and the system controller 472 are integrated to form a single processor.

  An overview of the flow of processing from image input to print output is as follows. Image data to be printed is input from the outside via the communication interface 470 and stored in the memory 474. At this stage, for example, RGB image data is stored in the memory 474.

  In the printing apparatus 10, a pseudo continuous tone image is formed by human eyes by changing the droplet ejection density and the dot size of fine dots with ink (coloring material). It is necessary to convert to a dot pattern that reproduces the tone (lightness of the image) as faithfully as possible. Therefore, the original image (RGB) data stored in the memory 474 is sent to the print control unit 480 via the system controller 472, and the print control unit 480 performs halftoning processing using a threshold matrix, an error diffusion method, or the like. Is converted into dot data for each ink color.

  That is, the print control unit 480 performs a process of converting the input RGB image data into dot data of four colors K, C, M, and Y. Thus, the dot data generated by the print control unit 480 is stored in the image buffer memory 482.

  The head driver 484 is a drive signal for driving the actuator 288 corresponding to each nozzle 281 of the ink head 210 based on print data (that is, dot data stored in the image buffer memory 482) given from the print control unit 480. Is output. The head driver 484 may include a feedback control system for keeping the head driving condition constant.

  When a drive signal output from the head driver 484 is applied to the head 210, ink is ejected from the corresponding nozzle 281. An image is formed on the recording medium 14 by controlling the ink ejection from the ink head 210 while conveying the recording medium 14 at a predetermined speed.

  The system controller 472 controls operations of the permeation inhibitor application control unit 502, the solvent drying control unit 504, and the hot-pressure fixing control unit 506.

  Further, the printing apparatus 10 of this example includes a processing liquid head 202 as a means for applying the processing liquid and a head driver 508 for driving the processing liquid head 202. The head driver 508 generates a drive signal to be applied to the actuator 288 of the treatment liquid head 202 based on the image data given from the print control unit 480, and drives the actuator 288 by applying the drive signal to the actuator 288. A drive circuit is included. As described above, a configuration in which the treatment liquid is ejected according to the image data, and a mode in which the treatment liquid is selectively ejected with respect to a position where the ink is ejected by the printing unit 28 is a preferable aspect. A mode of applying uniformly using a spray nozzle is also possible.

  In the case of the liquid application device 42, the permeation suppression agent application control unit 502 is a roller contact / separation mechanism drive unit for the spiral roller 48, a rotation drive unit for the spiral roller 48, a main blade contact / separation mechanism drive unit, a liquid jet A precision variable regulator or the like that adjusts the injection pressure of the unit 52 is controlled by the permeation suppression agent application control unit 502.

  The solvent drying control unit 504 controls the operation of the solvent drying unit 308 in the solvent drying unit 30 in accordance with an instruction from the system controller 472. That is, the driving of the heating unit 308 and the air blowing unit 310 provided in the solvent drying unit 30 is controlled.

  The heat and pressure fixing control unit 506 controls the operation of the stamp-type member 854 in the heat and pressure fixing unit 32 in accordance with an instruction from the system controller 472 and controls the operations of the heat rollers 328 a to 328 c and the cleaning unit 329.

  The system controller 472 receives data of measurement results such as a check pattern, moisture content, surface temperature, and glossiness from an inline sensor 348 disposed in the discharge unit 34.

<Printing action>
The recording medium 14 supplied from the paper feed tray 36 is fed to the peripheral surface of the pressure drum 40 of the permeation suppression processing unit 24 by a gripper (not shown) via the transfer drum 38.

  The recording medium 14 is stocked in advance in a paper feed unit (not shown) preheated to 40 to 50 ° C. before being sent to the paper feed tray 36. Then, the recording medium 14 is supplied to the transfer drum 38 while being in contact with the adhesive roller 37 provided at a position facing the paper feed surface of the paper feed tray 36. In this way, the recording medium 14 is heated and dried by preheating the paper feed unit, and by bringing the recording medium 14 into contact with the adhesive roller 37, foreign matters such as paper dust and dust can be removed. It is possible to increase the speed and stability of drying.

  The recording medium 14 is held on the pressure drum 40 of the permeation suppression processing unit 24 via the transfer cylinder 38, and a permeation suppression agent is selectively applied to a desired region by the liquid application device 42. Thereafter, the recording medium 14 held by the impression cylinder 40 is heated by the permeation inhibitor drying unit 46 while being guided by the sheet presser 44 while being fed in the rotation direction of the impression cylinder 40, and the solvent component (liquid) of the penetration inhibitor. Ingredient) evaporates and dries.

  The recording medium 14 thus subjected to the permeation suppression process is transferred from the pressure drum 40 of the permeation suppression processing unit 24 to the pressure drum 86 of the treatment liquid application unit 26 via the transfer cylinder 84. The processing liquid is ejected onto the recording medium 14 held on the impression cylinder 86 by the processing liquid head 202. Thereafter, the recording medium 14 held on the impression cylinder 86 is heated by the treatment liquid drying unit 204, and the solvent component (liquid component) of the treatment liquid is evaporated and dried. As a result, a solid or semi-solid aggregation treatment agent layer is formed on the recording medium 14.

  The recording medium 14 to which the treatment liquid is applied to form a solid or semi-solid aggregation treatment agent layer is transferred from the impression cylinder 86 of the treatment liquid application section 26 to the impression cylinder 216 of the printing section 28 via the transfer cylinder 214. Is passed on. Corresponding color inks are ejected from the respective ink heads 210K, 210C, 210M, and 210Y to the recording medium 14 held by the impression cylinder 216 in accordance with the input image data.

  When the ink droplet lands on the aggregation treatment agent layer, the contact surface between the ink droplet and the aggregation treatment agent layer lands in a predetermined area due to the balance between the flight energy and the surface energy. The aggregation reaction starts immediately after the ink droplets land on the aggregation treatment agent, but the aggregation reaction starts from the contact surface between the ink droplets and the aggregation treatment agent layer. The agglomeration reaction occurs only in the vicinity of the contact surface, and the color material in the ink is agglomerated in a state where the adhesive force is obtained with a predetermined contact area at the time of ink landing, so that the color material movement is suppressed.

  Even if other ink droplets land adjacent to this ink droplet, the color material of the ink that has landed first is already agglomerated, so the color materials do not mix with the ink that landed later, Bleed is suppressed. After the color material is aggregated, the separated ink solvent spreads, and a liquid layer in which the aggregation treatment agent is dissolved is formed on the recording medium 14.

  The recording medium 14 to which ink is applied is transferred from the pressure drum 216 of the printing unit 28 to the pressure drum 306 of the solvent drying unit 30 via the transfer drum 304.

  The recording medium 14 transferred from the transfer cylinder 304 to the impression cylinder 306 is instantaneously heated by coming into contact with the heated surface (conveying surface) of the impression cylinder 306. By passing through the blower unit 310 while the temperature of the recording medium 14 is applied, the water contained in the ink in the image formed by the printing unit 28 is blown off, and the water is sufficiently removed.

  Thereafter, the recording medium 14 is transferred from the pressure drum 306 of the solvent drying unit 30 to the pressure drum 326 of the hot-pressure fixing unit 32 via the transfer drum 324. A stamp-type member 325 is disposed on the transfer drum 324, and the stamp-type member 325 absorbs the high boiling point solvent and permeates the paper through the voids of the permeation suppression layer increased by the treatment liquid and heat drying. Then, the recording medium 14 delivered to the impression cylinder 326 heated by a heating means (not shown) is pressed and heat-pressed by the heat rollers 328a, 328b, 328c to fix the image on the recording medium 14.

  Thereafter, the recording medium 14 is transferred from the pressure drum 326 of the heat and pressure fixing unit 32 to the discharge tray 346 of the discharge unit 34 via the transfer drum 844 and discharged outside the apparatus. The transfer drum 344 is heated by a heating means (not shown), and further promotes the penetration of the high boiling point solvent and corrects the curl of the recording medium 14.

<Configuration of solvent drying unit (1)>
FIG. 7 is a schematic configuration diagram of the first embodiment of the solvent drying unit 30.

  As described above, the transfer cylinder 304 is provided between the impression cylinder 216 of the printing unit 28 and the impression cylinder 306 of the solvent drying unit 30, and the recording medium 14 to which each color ink is applied by the printing unit 28 is provided. Then, the pressure is transferred to the pressure drum 306 of the solvent drying unit 30 through the transfer drum 304.

  The pressure drum 306 of the solvent drying unit 30 is provided with a gripper (not shown), and the recording medium 14 rotates together with the pressure drum 306 by being gripped by the gripper.

  Around the pressure drum 306, a heating unit 308 and a blower unit 310 are provided in order from the upstream side in the rotation direction of the pressure drum 306.

  The heating unit 308 is constituted by three infrared heaters 308 a having substantially the same width as the pressure drum 306. The three infrared heaters 308a are each installed in parallel with the axis of the impression cylinder 306, and are arranged at a constant interval on a concentric circle centered on the axis of the impression cylinder 306. And the irradiation surface of the heat | fever is installed facing the surface of the impression cylinder 306, respectively.

  The heating unit 308 is installed on the upstream side of the blower unit 310 and on the conveyance path of the recording medium 14. That is, the recording medium 14 is installed so as to be conveyed through the heating unit 308.

  The pressure drum 306 is provided with a temperature sensor (not shown) to detect the temperature of the pressure drum. The system controller 472 controls the driving of the heating unit 308 based on the temperature information of the conveying surface detected by this temperature sensor, and controls the surface temperature of the impression cylinder 306 (the temperature of the conveying surface).

  The heating unit 308 configured in this manner indirectly heats the surface (conveying surface) of the pressure drum 306 by irradiating heat from each infrared heater 308a toward the surface of the pressure drum 306. Further, the recording medium 14 can be heated by being conveyed through the heating unit 308.

  The blower unit 310 is composed of four blowers 310 a having blower openings having substantially the same width as the pressure drum 306. Each of the four blowers 310a is installed in parallel with the axis of the impression cylinder 306, and is installed at a constant interval on a concentric circle centered on the axis of the impression cylinder 306. The air blowing ports are respectively installed facing the surface of the impression cylinder 306.

  The blower unit 310 is installed on the downstream side of the heating unit 308 and on the conveyance path of the recording medium 14. That is, the recording medium 14 is installed so as to be transported through the air blowing unit 310 after passing through the heating unit 308.

  The air blowing unit 301 configured in this manner blows room temperature air from each blower 310 a, thereby blowing room temperature air to the recording medium 14 conveyed by the impression cylinder 306.

  According to the solvent drying unit 30 configured as described above, the recording medium 14 transferred from the transfer drum 304 to the pressure drum 306 of the solvent drying unit 30 is the surface of the pressure drum 306 heated by the heating unit 308 ( By contacting the transport surface), it is heated instantaneously. By passing through the blower unit 310 while the temperature of the recording medium 14 is in contact, moisture contained in the ink in the image formed by the printing unit 28 can be efficiently blown off, and the image quality performance is greatly improved. Can be made.

  In particular, when printing is performed with water-based ink using general-purpose printing paper as a recording medium, the ink tends to bleed into the paper. By blowing the water, moisture can be efficiently blown off, and the image quality performance can be greatly improved.

  In addition, when performing high-speed and large-volume printing, the conventional method of blowing hot air to dry increases power consumption, but as in the present embodiment, preheating of the impression cylinder 306, In the method using air blowing at room temperature, the power consumption is kept low and the method is highly energy efficient.

  In the above example, the temperature of the impression cylinder 306 (conveying surface temperature) is not particularly mentioned, but the temperature of the impression cylinder 306 is set to a target temperature within a range of 40 ° C. to 70 ° C. It is preferable to control so as to maintain the temperature.

  Moreover, it is preferable that the impression cylinder 306 is heated at the time of starting the apparatus and is controlled to a constant temperature before the operation is started.

  FIG. 8 is a time chart for raising the temperature of the impression cylinder when the apparatus is activated. As shown in the figure, the heating unit 308 is driven at full power when the apparatus is activated, and the impression cylinder 306 is heated to the target temperature. Then, the heating unit 308 is driven and controlled to reach a constant temperature when the target temperature is reached, and the temperature of the impression cylinder 306 is stabilized before the operation is started.

  As described above, the impression cylinder 306 is heated to the target temperature all at once when the apparatus is activated. However, once the pressure drum 306 is heated to the predetermined temperature, no particularly large heat is required to maintain the temperature. Therefore, it can be operated with low power consumption during operation (printing).

  In addition, since the heating unit 308 is provided on the conveyance path of the recording medium 14 in the solvent drying unit 30 of the present embodiment, the heat irradiated from the heating unit 308 is also used for heating the recording medium 14. Can do. In this case, the temperature control of the impression cylinder 306 is performed in a gap (between the previous recording medium and the subsequent recording medium) between the recording media 14 to be sequentially printed. That is, it is performed while the impression cylinder 306 is exposed.

  FIG. 9 is a timing chart of the heating control of the impression cylinder. As shown in the figure, while the recording medium 14 passes, the heating unit 308 is driven at full power. Then, the driving of the heating unit 308 is controlled while the impression cylinder 306 is exposed, and the temperature of the impression cylinder 306 is controlled.

  Accordingly, the pressure drum 306 can be efficiently heated to a predetermined temperature while using the heat from the heating unit 308 to raise the temperature of the recording medium 14.

  As described above, the impression cylinder 306 is preliminarily heated when the apparatus is activated. Therefore, in order to shorten the preheating time, it is preferable to form the impression cylinder 306 in a shape having a small heat capacity, for example, a hollow cylindrical shape.

  In the above example, the air blowing speed blown from the blower unit 310 to the recording medium 14 is not particularly mentioned, but the air blowing speed blown from the blower unit 310 to the recording medium 14 is set to 20 m / s or less. It is preferable to set it within a range of 5 m / s or more and 20 m / s or less. Therefore, it can be set to about 5 m / s. In this example, it is set to about 5 m / s.

  Further, the wind can be applied vertically to the recording medium 14 or can be applied obliquely (structure applied to the recording medium 14 at an acute angle).

  The impression cylinder 306 preferably includes a suction holding mechanism for the recording medium 14 in order to improve the adhesion of the recording medium 14. That is, a plurality of suction holes are formed on the surface, air is sucked into the inside from the suction holes, and a mechanism for sucking and holding the recording medium 14 on the surface is provided. As a result, the recording medium 14 adheres to the surface of the impression cylinder 306, and the recording medium 14 can be heated more efficiently.

  Note that the number of infrared heaters 308a constituting the heating unit 308 is not particularly limited, and the number of infrared heaters 308a can be appropriately increased or decreased according to an installation space or the like. However, the impression cylinder 306 can be heated more efficiently by increasing the number of infrared heaters.

  Similarly, the number of blowers 310a constituting the blower unit 310 is not particularly limited, and the blower units 310a can be appropriately increased or decreased according to the installation space or the like. However, the recording medium 14 can be dried more efficiently by increasing the number of blowers.

  Moreover, in this Embodiment, although the heating unit is comprised with the infrared heater, the means to heat an impression cylinder indirectly is not limited to this. In addition, it can also be set as the structure heated using heating means, such as a halogen heater.

<Configuration of solvent drying unit (2)>
FIG. 10 is a schematic configuration diagram of the second embodiment of the solvent drying unit.

  The solvent drying unit 30A of the present embodiment is different from the configuration of the solvent drying unit 30 of the first embodiment described above in that the heating unit 308 is installed in a region other than the conveyance path of the recording medium 14. ing.

  As shown in FIG. 10, the solvent drying unit 30 </ b> A according to the present embodiment has a heating unit downstream of the blower unit 310 with respect to the rotation direction of the impression cylinder 306 and in a region other than the conveyance path of the recording medium 14. 308 is installed. Therefore, the recording medium 14 is not conveyed through the heating unit 308.

  The configuration itself of the heating unit 308 is the same as that of the solvent drying unit 30 of the first embodiment described above. That is, it is composed of three infrared heaters 308a having substantially the same width as that of the impression cylinder 306, and the three infrared heaters 308a are installed on a concentric circle centered on the axis of the impression cylinder 306 at a constant interval. Yes. And the irradiation surface of the heat | fever is installed facing the surface of the impression cylinder 306, respectively.

  In the solvent drying unit 30 of the first embodiment, since the heating unit 308 is installed on the conveyance path of the recording medium 14, the pressure drum 306 is heated in the gap of the recording medium 14 during printing. However, in the solvent drying unit 30A of the present embodiment, since the heat of the heating unit 308 can always be applied to the impression cylinder 306, the impression cylinder 306 can be efficiently heated and heated uniformly. Can do. Further, the temperature of the impression cylinder 306 can be controlled with high accuracy.

<Configuration of solvent drying unit (3)>
FIG. 11 is a schematic configuration diagram of a third embodiment of the solvent drying unit.

  The solvent drying unit 30B according to the present embodiment includes a first heating unit 308A installed on the conveyance path of the recording medium 14 and a second heating unit 308B installed in an area other than the conveyance path of the recording medium 14. This is different from the solvent drying unit 30 of the first and second embodiments described above.

  As shown in FIG. 11, the first heating unit 308 </ b> A is installed on the conveyance path of the recording medium 14 on the upstream side of the blower unit 310 with respect to the rotation direction of the impression cylinder 306. Therefore, the recording medium 14 is conveyed under the first heating unit 308A.

  On the other hand, the second heating unit 308 </ b> B is installed in a region other than the conveyance path of the recording medium 14 on the downstream side of the blower unit 310 with respect to the rotation direction of the impression cylinder 306. Accordingly, the recording medium 14 is not transported through the second heating unit 308B.

  Note that the basic configuration of any heating unit is the same as that of the heating unit 308 of the solvent drying unit 30 of the first embodiment described above. That is, it is composed of three infrared heaters 308A having substantially the same width as that of the impression cylinder 306, and the three infrared heaters 308A are arranged on a concentric circle centered on the axis of the impression cylinder 306 at a constant interval. Yes. And the irradiation surface of the heat | fever is installed facing the surface of the impression cylinder 306, respectively.

  According to the solvent drying unit 30B of the present embodiment, since the first heating unit 308A is installed on the transport path of the recording medium 14, the first heating unit 308A heats the impression cylinder 306 and the recording medium. A temperature increase of 14 can be performed. Thereby, the recording medium 14 can be efficiently heated and dried.

  Further, according to the solvent drying unit 30B of the present embodiment, since the second heating unit 308B is installed in a region other than the conveyance path of the recording medium 14, only the impression cylinder 306 is used by the second heating unit 308B. Can be heated. As a result, the impression cylinder 306 can be heated uniformly and efficiently, and the temperature of the impression cylinder 306 can be accurately controlled.

<Configuration of solvent drying unit (4)>
FIG. 12 is a schematic configuration diagram of a fourth embodiment of the solvent drying unit.

  The solvent drying unit 30C of the present embodiment is different from the solvent drying unit 30 of the first and second embodiments described above in that the pressure drum 306 is directly heated by a heating unit 312 incorporated in the pressure drum 306. ing.

  As shown in FIG. 12, the heating unit 312 is composed of a heater (for example, a rubber heater) formed in a sheet shape, and is directly attached to the inner peripheral portion of the impression cylinder 306 formed in a hollow cylindrical shape. ing. The heating unit 312 is attached over the entire inner peripheral portion of the impression cylinder 306, and directly heats the impression cylinder 306 from the inside.

  The pressure drum 306 is provided with a temperature sensor (not shown). The system controller 472 controls the driving of the heating unit 312 based on the temperature information of the conveying surface detected by the temperature sensor, and Controls temperature (conveying surface temperature).

  According to the solvent drying unit 30C of the present embodiment, the pressure drum 306 can be efficiently heated because the pressure drum 306 is directly heated by the heating unit 312 incorporated in the pressure drum 306.

  In addition, since the heating efficiency is good, the impression cylinder 306 can be heated to the target temperature in a short time when the apparatus is activated.

  In this embodiment, the heater formed in a sheet shape is attached to the inner peripheral portion of the cylindrical impression cylinder 306, and the impression cylinder 306 is directly heated. The means for directly heating 306 is not limited to this. The pressure drum 306 may be directly heated using other heating means.

<Configuration of solvent drying unit (5)>
FIG. 13 is a schematic configuration diagram of a fifth embodiment of the solvent drying unit.

  The solvent drying unit 30 </ b> D according to the present embodiment is provided around the pressure drum 306 while directly heating the pressure drum 306 by a heating unit 312 (hereinafter referred to as a direct heating unit) incorporated in the pressure drum 306. The impression cylinder 306 is indirectly heated by a first heating unit (hereinafter referred to as a first indirect heating unit) 308A and a second heating unit (hereinafter referred to as a second indirect heating unit) 308B.

  As shown in FIG. 13, the direct heating unit 312 is composed of a heater (eg, a rubber heater) formed in a sheet shape, and is directly attached to the inner peripheral portion of the impression cylinder 306 formed in a hollow cylindrical shape. Has been. The direct heating unit 312 is attached over the entire inner peripheral portion of the impression cylinder 306, and directly heats the impression cylinder 306 from the inside.

  The first indirect heating unit 308A is installed on the conveyance path of the recording medium 14 on the upstream side of the air blowing unit 310 with respect to the rotation direction of the impression cylinder 306, and irradiates the surface of the impression cylinder 306 with heat. The impression cylinder 306 is indirectly heated. Since the first indirect heating unit 308A is installed on the conveyance path of the recording medium 14, the first indirect heating unit 308A heats the impression cylinder 306 and heats the recording medium 14 passing therethrough.

  The second indirect heating unit 308B is installed on the downstream side of the blower unit 310 with respect to the rotation direction of the pressure drum 306 and in a region other than the conveyance path of the recording medium 14, and heats the surface of the pressure drum 306. Irradiation heats the impression cylinder 306 indirectly. Since the second indirect heating unit 308B is installed in an area other than the conveyance path of the recording medium 14, only the impression cylinder 306 is heated. Thereby, the impression cylinder 306 can be efficiently heated without unevenness.

  In the solvent drying unit 30 </ b> D of the present embodiment, the direct heating unit 312 incorporated in the impression cylinder 306 directly heats the impression cylinder 306, and first and second indirect heating provided around the impression cylinder 306. The impression cylinder 306 is indirectly heated by the units 308A and 308B.

  By directly heating the pressure drum 306 by the direct heating unit 312, the heating efficiency of the pressure drum 306 can be increased, and the pressure drum 306 can be heated to the target temperature in a short time when the apparatus is activated.

  Further, by indirectly heating the pressure drum 306 with the second indirect heating unit 308A provided in a region other than the conveyance path of the recording medium 14, the pressure drum 306 can be heated without unevenness.

  Furthermore, by indirectly heating the pressure drum 306 with the first indirect heating unit 308A provided on the conveyance path of the recording medium 14, the recording medium 14 can be heated simultaneously with the heating of the pressure drum 306. The recording medium 14 can be efficiently heated and dried.

  In this example, the direct heating unit 312 is used in combination with the first and second indirect heating units 308A and 308B, but only one of the first and second indirect heating units 308A and 308B is combined. May be. In other words, the pressure drum 306 may be directly heated by the direct heating unit 312 and the pressure drum 306 may be indirectly heated by the first indirect heating unit 308A. Alternatively, the pressure drum 306 may be directly heated by the direct heating unit 312. While directly heating 306, it is good also as a structure which heats the impression cylinder 306 indirectly by the 2nd indirect heating unit 308B.

<Other configuration of solvent drying unit>
In the series of embodiments described above, the recording medium 14 is conveyed by the impression cylinder in the solvent drying unit, but the means for conveying the recording medium 14 is not limited to this. For example, as shown in FIG. 14, it can also be set as the structure conveyed by the conveyor 314. FIG.

  The conveyor 314 is configured by winding an endless belt 316 around a pair of pulleys 318 and is driven to rotate by a motor (not shown) connected to one pulley 318. The recording medium 14 is conveyed by being gripped by a gripper (not shown) provided on the belt 316 of the conveyor 314.

  In the example shown in the figure, the first heating unit 308A and the second heating unit 308B provided around the conveyor 314 are configured to indirectly heat the conveyor 314. The first heating unit A blower unit 310 installed on the downstream side of 308A is configured to blow normal temperature wind onto the recording medium 14 being conveyed.

  The first heating unit 308A is provided on the conveyance path of the recording medium 14, and the second heating unit 308B is provided in an area other than the conveyance path of the recording medium 14.

  In the example shown in the figure, the first heating unit 308A and the second heating unit 308B are used in combination, but only one of them may be installed. Further, a configuration in which a heating unit that directly heats the belt 316 is used in combination, or only a heating unit that directly heats the belt 316 may be used.

<Experiment 1>
In the solvent drying section having the configuration shown in FIG. 7, an experiment was conducted to check the amount of remaining water in the recording medium 14 by changing the speed of the air blown onto the recording medium 14 (blowing speed) under a plurality of conditions.

  Specifically, a recording medium printed under the same conditions (a recording medium on which the same image is printed using the same processing liquid and the same ink) is conveyed at a predetermined conveyance speed, and the temperature of the stage (temperature of the impression cylinder), blower The amount of water remaining in the recording medium 14 was examined by changing the number of installations and the blowing temperature (the set temperature of the blower), changing the experimental conditions, and changing the blowing speed under each condition.

  Here, the temperature of the stage (temperature of the impression cylinder) was set to 40 ° C. and 60 ° C., and the number of blowers installed was set to 3 and 1. Moreover, about blowing temperature (setting temperature of a blower), it set to 120 degreeC, 60 degreeC, and normal temperature (C: COOL).

In addition, “Tokuhishi Art” (basis weight 84.9 g / m ² ) manufactured by Mitsubishi Paper Industries Co., Ltd. was used as the recording medium, and the conveyance speed was set to 535 mm / s.

  FIG. 15 is a graph showing the results of this experiment. As shown in the figure, it was confirmed that when the air blowing speed exceeded a predetermined speed, the remaining water amount was hardly affected.

  Therefore, by setting the air blowing speed within a necessary and sufficient range that can contribute to drying (approximately 20 m / s or less), it is possible to operate without wasting power.

  Further, it was confirmed that the higher the impression cylinder temperature (stage temperature), the higher the drying effect.

<Experiment 2>
In the solvent drying section having the configuration shown in FIG. 7, an experiment was conducted to check the amount of residual water in the recording medium 14 by changing the temperature of the air blown onto the recording medium 14 (air blowing temperature) under a plurality of conditions.

  Specifically, a recording medium printed under the same conditions (a recording medium on which the same image is printed using the same processing liquid and the same ink) is conveyed at a predetermined conveyance speed, and the temperature of the stage (temperature of the impression cylinder), blower The amount of water remaining in the recording medium 14 was examined by changing the experiment conditions by changing the number of installed and the blower blowing amount, and changing the blowing temperature under each condition.

  Here, the temperature of the stage (temperature of the impression cylinder) was set to 40 ° C. and 60 ° C., and the number of blowers installed was set to 3 and 1. Further, the blower blowing amount was set to L (Low), H (High), and T (Turbo) (the blowing amount increases in the order of L <H <T).

In addition, “Tokuhishi Art” (basis weight 84.9 g / m ² ) manufactured by Mitsubishi Paper Industries Co., Ltd. was used as the recording medium, and the conveyance speed was set to 535 mm / s.

  FIG. 16 is a graph showing the results of this experiment. As shown in the figure, it was confirmed that the blast temperature had almost no effect on the amount of residual water.

  Therefore, it can drive | operate, without consuming electric power wastefully by setting ventilation temperature to normal temperature.

  Further, it was confirmed that the higher the impression cylinder temperature (stage temperature), the higher the drying effect.

<Experiment 3>
In the solvent drying section having the configuration shown in FIG. 7, an experiment was conducted in which the temperature of the impression cylinder (stage) was changed under a plurality of conditions to check the remaining water amount of the recording medium 14.

  Specifically, a recording medium printed under the same conditions (a recording medium on which the same image is printed using the same processing liquid and the same ink) is conveyed at a predetermined conveyance speed, and the blowing temperature (the set temperature of the blower) and the blowing The amount of residual water in the recording medium 14 was examined by changing the experimental conditions by changing the presence or absence of the ink and changing the temperature of the stage (the temperature of the impression cylinder) under each condition.

  Here, the blowing temperature (set temperature of the blower) was set to 120 ° C., 60 ° C., and normal temperature (C: COOL). Three blowers were used, and the air flow rate was set to L (Low).

In addition, “Tokuhishi Art” (basis weight 84.9 g / m ² ) manufactured by Mitsubishi Paper Industries Co., Ltd. was used as the recording medium, and the conveyance speed was set to 535 mm / s.

  FIG. 17 is a graph showing the results of this experiment. As shown in the figure, it was confirmed that the amount of residual water can be reduced as the temperature of the impression cylinder (stage) is set higher.

  Moreover, it has confirmed that the amount of residual water could be reduced more by performing ventilation.

<Experiment 4>
In the solvent drying section having the configuration shown in FIG. 7, an experiment was conducted to check the amount of residual water in the recording medium 14 by changing the number of blowers installed under a plurality of conditions.

  Specifically, a recording medium printed under the same conditions (a recording medium on which the same image is printed using the same processing liquid and the same ink) is conveyed at a predetermined conveyance speed, and the temperature of the stage (temperature of the impression cylinder), blower The amount of remaining water in the recording medium 14 was examined by changing the experimental conditions by changing the blowing amount and the blowing temperature (the set temperature of the blower), and changing the number of blowers installed under each condition.

  Here, the temperature of the stage (temperature of the impression cylinder) was set to 40 ° C. and 60 ° C., and the blower air volume was set to L (Low), H (High), and T (Turbo). Moreover, about blowing temperature (setting temperature of a blower), it set to 120 degreeC, 60 degreeC, and normal temperature (C: COOL).

In addition, “Tokuhishi Art” (basis weight 84.9 g / m ² ) manufactured by Mitsubishi Paper Industries Co., Ltd. was used as the recording medium, and the conveyance speed was set to 535 mm / s.

  FIG. 18 is a graph showing the results of this experiment. As shown in the figure, it was confirmed that the amount of residual water can be reduced by increasing the number of blowers installed.

  Further, it was confirmed that the higher the impression cylinder temperature (stage temperature), the higher the drying effect.

<Summary>
Drying can be promoted by blowing air, but it was confirmed that even if the temperature was increased, it hardly contributed to the promotion of drying. Therefore, it was confirmed that air blowing at normal temperature was the most energy efficient.

  In addition, it was confirmed that even if the air blowing speed was increased above a certain speed, it did not contribute to the promotion of drying. Therefore, by setting the air blowing speed within a range that can contribute to drying, an operation with high energy efficiency can be performed.

  Moreover, it was confirmed that the impression cylinder (including the conveyor) had a higher drying effect as the temperature of the conveying surface (stage) was higher.

  Moreover, it was confirmed that the drying effect can be enhanced by increasing the number of blowers installed.

1 is an overall configuration diagram of an ink jet recording apparatus according to an embodiment of the present invention. Plane perspective view showing a configuration example of an ink head Plan view showing another configuration example of the head Sectional drawing which follows the BB line in FIG. Plan view showing an example of nozzle arrangement of the head Block diagram showing system configuration of inkjet recording apparatus Schematic configuration diagram of the first embodiment of the solvent drying unit Temperature rise time chart of the impression cylinder at the start-up of the device Impression heating control timing chart Schematic configuration diagram of the second embodiment of the solvent drying unit Schematic configuration diagram of the third embodiment of the solvent drying unit Schematic configuration diagram of the fourth embodiment of the solvent drying unit Schematic configuration diagram of fifth embodiment of solvent drying unit Schematic configuration diagram of another embodiment of the solvent drying unit A graph showing the relationship between the blowing speed and the amount of residual water Graph showing the relationship between air temperature and amount of residual water Graph showing the relationship between the temperature of the stage (impression cylinder) and the amount of residual water Graph showing the relationship between the number of blowers and the amount of residual water

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printing apparatus, 14 ... Recording medium, 24 ... Penetration suppression processing part, 26 ... Treatment liquid application part, 28 ... Printing part, 30 ... Solvent drying part, 32 ... Hot-pressure fixing part, 34 ... Discharge part, 304 ... Delivery Cylinder, 306 ... Impression cylinder, 308 ... Heating unit, 308a ... Infrared heater, 310 ... Blower unit, 310a ... Blower, 308A ... First heating unit (first indirect heating unit), 308B ... Second heating unit ( (Second indirect heating unit), 312 ... heating unit (direct heating unit), 314 ... conveyor, 472 ... system controller

Claims (9)

In a printing apparatus provided with a drying unit for drying a sheet-like recording medium immediately after printing,
The drying unit
Conveying means for placing a recording medium on a rotating endless conveying surface and conveying the recording medium along a predetermined conveying path;
Heating means for heating the conveying surface of the conveying means;
Air blowing means for blowing air at normal temperature onto the recording medium conveyed by the conveying means;
A printing apparatus comprising:   2. The printing apparatus according to claim 1, wherein the heating unit includes a direct heating unit that directly heats a heat source in contact with the inside of the transport surface. The heating means includes
Direct heating means for heating directly by bringing a heat source into contact with the inside of the conveying surface;
Indirect heating means for irradiating heat to the transport surface and heating indirectly,
The printing apparatus according to claim 1, comprising:   The printing apparatus according to claim 1, wherein the heating unit includes an indirect heating unit that irradiates heat to the conveyance surface and indirectly heats the conveyance surface.   The printing apparatus according to claim 4, wherein the indirect heating unit irradiates the transport surface with heat on a transport path of the recording medium.   The printing apparatus according to claim 4, wherein the indirect heating unit irradiates heat on the transport surface other than the transport path of the recording medium. The indirect heating means includes
A first indirect heating means for irradiating the transport surface with heat on a transport path of the recording medium;
A second indirect heating means for irradiating the transport surface with heat outside the transport path of the recording medium;
The printing apparatus according to claim 3, wherein the printing apparatus is configured as follows.   The said heating means heats the said conveyance surface to 40 to 70 degreeC, and the said ventilation means ventilates at the speed | rate of 20 m / s or less, It is characterized by the above-mentioned. Printing device.   The printing apparatus according to claim 1, wherein the recording medium is general-purpose printing paper.

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