JP5934624B2 - Drying device, printing device equipped with drying device, and drying method - Google Patents

Description

  The present invention relates to a technique for drying a recording medium to which a liquid is attached.

  In recent years, inkjet recording apparatuses that discharge aqueous inks such as aqueous dye inks and aqueous pigment inks from the viewpoint of environmental protection have become widespread. Since water-based ink has a low drying speed, when printing at high speed, the ink on the recording medium after printing becomes insufficiently dried, and the ink that has not been dried adheres to various rollers on the downstream side or overlaps after applying ink. There arises a problem that a plurality of recorded sheets adhere to each other. For this reason, the ink jet recording apparatus is usually provided with a drying mechanism in order to quickly dry the ink discharged onto the recording paper (recording medium).

  For example, the printing apparatus of Patent Document 1 prints a plurality of types of inks having different drying characteristics on a recording medium such as paper. In order to suppress excessive heating of the recording medium, the apparatus includes a pair of a print head that ejects ink and a lamp that can apply fixing energy according to the type of ink for each of a plurality of inks. A plurality of pairs of print heads and lamps are arranged in the order of ink discharge along the recording medium conveyance direction.

  In the apparatus of Patent Document 1, unevenness in drying occurs when the ink density varies in the width direction of the recording medium. Further, since the responsiveness of the lamp is usually poor, when the ink density fluctuates in the carrying direction, there is a problem in that as the carrying speed increases, the lamp response becomes unable to follow the fluctuating speed of the ink density, resulting in drying unevenness. .

  In the apparatuses of Patent Documents 2 and 3, the ink discharged onto the recording medium is placed inside the roller along the direction of the axis of symmetry of the cylindrical heat-fixing roller, that is, the width direction orthogonal to the conveying direction of the recording medium such as paper. A plurality of induction heaters for drying are provided. The entire area of the recording medium is divided into a plurality of partial areas arranged in the width direction, and each partial area is heated by a corresponding induction heater. For each partial region, the area ratio of the portion where ink is ejected relative to the total area of the partial region, that is, the ink adhesion density is determined. Each heater is controlled in accordance with the adhesion density so as to heat the recording medium to a higher temperature as the ink adhesion density in the corresponding partial region is higher.

  In the devices of Patent Documents 2 and 3, since the induction heaters having better responsiveness than the lamp are arranged in the width direction, drying unevenness hardly occurs when the ink density changes in the width direction of the recording medium.

JP 2011-161756 A JP 2007-76060 A JP 2008-183718 A

  However, in the apparatuses of Patent Documents 2 and 3, since the amount of heat supplied for each partial region in which the recording medium is divided in the width direction is controlled, the ink adhesion density varies greatly along the recording medium conveyance direction. Causes uneven drying. There is also a problem that uneven drying occurs even when the amount of heat that can be supplied by the induction heater is less than the amount of heat necessary for drying.

  The present invention has been made to solve these problems, and the fluctuation range of the density of the liquid adhering to the recording medium in the width direction and the conveying direction of the recording medium is large, and the conveying speed of the recording medium is high. However, an object is to provide a technique capable of drying a recording medium at a high speed while suppressing drying unevenness.

  In order to solve the above-described problem, a drying apparatus according to a first aspect is a drying apparatus that dries a recording medium having a liquid adhering to a recording surface, and has a predetermined conveying speed along a predetermined processing line. The light that crosses the target area in the width direction substantially orthogonal to the processing line is irradiated toward the recording surface of the predetermined target area of the recording medium that is conveyed relative to the drying device. Accordingly, a light irradiation unit that heats the liquid adhering to the recording surface of the target area, a first power supply unit that supplies power to the light irradiation unit, and heat generated by an electromagnetic induction heating method A plurality of electromagnetic induction coils for heating the target area of the recording medium by providing the back of the recording area of the target area, and a second power supply unit for supplying high frequency power to each of the plurality of electromagnetic induction coils When, A control unit that controls power supply to each of the light irradiation unit and the plurality of electromagnetic induction coils, and the plurality of electromagnetic induction coils are set in advance to divide the target region along the width direction, respectively. The plurality of first sections are sequentially arranged along the width direction on the back surface side of the recording surface with respect to the recording medium so that each of the plurality of first sections can be heated. Area information defining a plurality of block areas divided in a lattice shape by being divided into a plurality of first sections along a direction and a plurality of second sections along the processing line. Based on the area information acquisition unit to be acquired, the image data corresponding to the visual information recorded in the target area, and the area information, each of the plurality of block areas is subjected to drying. Based on the block heat quantity acquisition unit for acquiring the heat quantity of each of the blocks and the plurality of block heat quantities respectively corresponding to the plurality of block areas, the light irradiation unit uniformly supplies the entire target area over a predetermined area. For each of the plurality of block regions, the first heat quantity acquisition unit that acquires the first heat quantity, the heat quantity supplied by the light irradiation unit is acquired based on the first heat quantity, and the acquired heat quantity is subtracted from the block heat quantity. A second heat quantity acquisition unit that acquires the remaining heat quantity as a second heat quantity supplied by the plurality of electromagnetic induction coils, and the light irradiation unit uniformly distributes the first heat quantity per predetermined area over the entire target area. And supplying the corresponding second heat quantity to each of the plurality of block regions by the corresponding coil among the plurality of electromagnetic induction coils. As described above, a power control unit that controls each of the first power supply unit and the second power supply unit is provided.

  The drying device according to the second aspect is the drying device according to the first aspect, wherein the first heat quantity acquisition unit is configured to per a predetermined area for a plurality of the block heat quantities respectively corresponding to the plurality of block areas. The minimum value is acquired as the first amount of heat.

  A drying device according to a third aspect is the drying device according to the first or second aspect, wherein the power control unit is a unit area of the second heat quantity for a target block region among the plurality of block regions. When the amount of heat per unit area is larger than the amount of heat per unit area of the second heat amount for the block region downstream of the processing line with respect to the block region of interest, among the plurality of electromagnetic induction coils The corresponding block region corresponds to the high frequency power having an effective value larger than the fixed effective high frequency power required for the corresponding coil that heats the target region to supply the second heat quantity corresponding to the target block region. The second power supply unit is controlled so as to be supplied to the corresponding coil over an initial part of the period heated by the coil.

  A printing apparatus according to a fourth aspect includes a drying apparatus according to any one of the first to third aspects, and the recording medium relative to the drying apparatus at the transport speed along the processing line. A transport mechanism that transports the recording apparatus; and a recording head that is provided on the upstream side of the processing line with respect to the drying apparatus and that discharges the liquid and records visual information on the recording medium.

  A drying method according to a fifth aspect is a drying method for drying a recording medium having a liquid adhered to a recording surface by a drying device, wherein the drying device is at a predetermined transport speed along a predetermined processing line. Irradiating light that crosses the target area in a width direction substantially orthogonal to the processing line toward the recording surface of a predetermined target area of the recording medium that is conveyed relative to the drying apparatus. The light irradiation unit that heats the liquid adhering to the recording surface of the target area, the first power supply unit that supplies power to the light irradiation unit, and the heat generated by the electromagnetic induction heating method A plurality of electromagnetic induction coils that heat the target area of the recording medium by giving to the back surface of the recording surface of the target area, and a second power supply unit that supplies high frequency power to each of the plurality of electromagnetic induction coils A control unit that controls power supply to each of the light irradiation unit and the plurality of electromagnetic induction coils, and the plurality of electromagnetic induction coils are preset in each of which the target region is divided along the width direction. In order to be able to heat each of the plurality of first sections formed, the recording medium is sequentially arranged along the width direction on the back side of the recording surface with respect to the recording medium. Area information that defines a plurality of block areas divided into a lattice by being divided into a plurality of first sections along the width direction and a plurality of second sections along the processing line Region information acquisition step for acquiring image data, image data corresponding to visual information recorded in the target region, and the region information. Based on the block heat quantity acquisition step for acquiring the block heat quantity required for each of the plurality of block areas and the plurality of block heat quantities respectively corresponding to the plurality of block areas, the light irradiation unit supplies the entire target area evenly per predetermined area. A first heat quantity acquisition step for obtaining a first heat quantity, and for each of the plurality of block regions, the heat quantity supplied by the light irradiation unit is obtained based on the first heat quantity, and the obtained heat quantity is obtained from the block heat quantity. A second heat quantity acquisition step of acquiring the reduced remaining heat quantity as a second heat quantity supplied by the plurality of electromagnetic induction coils; and the light irradiation unit supplies the first heat quantity per the predetermined area of the target region. , For each of the plurality of block regions, the corresponding second heat quantity is assigned to the corresponding coil of the plurality of electromagnetic induction coils. And a power control step for controlling the first power supply unit and the second power supply unit, respectively, so that the power supply is performed.

  According to the present invention, the target area of the storage medium to which the liquid has adhered is dried for each of the plurality of block areas that are partitioned in a lattice shape by being partitioned along both the width direction and the processing line. The required block heat quantity is acquired. A first amount of heat supplied by the light irradiation unit per predetermined area is acquired based on each block heat amount, and a second amount of heat supplied by the electromagnetic induction coil out of the block heat amount of each block region based on the first amount of heat is obtained. To be acquired. And the heating by the electric power supply according to the acquired heat amount is performed by the light irradiation part and the electromagnetic induction coil. That is, for each block area in which the target area is divided into a grid, the amount of heat required for heating is distributed to the light irradiation unit and the electromagnetic induction coil having better response than the light irradiation unit, and heating is performed by both. Is called. This makes it possible to supply a larger amount of heat to the recording medium than when only one of the light irradiation unit and the electromagnetic induction coil is used, and is better than when only the light irradiation unit is used. Responsiveness is achieved for both the width direction and the processing line direction. Therefore, even when the fluctuation range of the density of the liquid adhering to the recording medium is large in the width direction of the recording medium and the processing line direction and the conveying speed is high, the recording medium can be dried at high speed while suppressing drying unevenness.

1 is a block diagram illustrating an example of a schematic configuration of a recording apparatus according to an embodiment. It is a figure for demonstrating an example of a structure and operation | movement of the drying apparatus which concerns on embodiment. It is a figure which illustrates the relationship between the moisture content on a recording medium, and the calorie | heat amount required for drying. It is a figure for demonstrating the process which improves the response of the output of an electromagnetic induction coil. It is a flowchart which shows an example of operation | movement of the drying apparatus which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, parts having the same configuration and function are denoted by the same reference numerals, and redundant description is omitted in the following description. Each drawing is schematically shown. For example, the size and positional relationship of display objects in each drawing are not necessarily shown accurately. In addition, in some drawings, coordinate axes of an XYZ orthogonal coordinate system are attached to explain directions. The X-axis and Z-axis directions are the horizontal direction, and the Y-axis direction is the vertical direction (the + Y side is the upper side).

<A. Embodiment>
<A-1. Configuration of recording apparatus>
FIG. 1 is a block diagram illustrating an example of a schematic configuration of a recording apparatus 100A according to the first embodiment. Drawing 2 is a figure for explaining an example of the operation while showing an example of schematic structure of drying device 42A concerning an embodiment. FIG. 2 shows a schematic configuration of the configuration of the recording apparatus 100 </ b> A shown in FIG. 1, in which the configuration around the conveyance plate 31 holding the recording paper 1 is viewed vertically upward (+ Y direction) from below the conveyance plate 31. It is shown. The recording apparatus 100 </ b> A ejects water-based ink (also simply referred to as “liquid”) as droplets onto a recording sheet (also referred to as “recording medium”) 1 by an ink-jet method, so that images, characters, etc. This is an apparatus for recording visual information on the recording paper 1. As the recording paper 1, for example, a recording paper for offset printing, a coated paper such as a so-called photographic paper or matte paper, on which a coating agent for forming a glossy coating layer is applied on a paper such as the recording paper, etc. For example, plain paper may be used.

  The recording apparatus 100A includes, for example, a light irradiation unit 5, electromagnetic induction coils 21 to 23, a transport plate 31, a recording head unit 41, a transport system drive device 44, a paper discharge device 45, a paper feed device 46, transport rollers 51 and 52, The conveyor belt 55, the first power supply unit 71, the second power supply unit 72, the storage unit 81, the control unit 90, and the like are mainly provided.

  The paper feeding device 46 includes a plurality of recording papers 1. With the rectangular conveyance plate 31 fixed to the conveyance belt 55 located below the paper feeding device 46, the recording paper 1 is fed onto the conveyance plate 31 from the paper feeding device 46 by a single-wafer type and electrostatically charged. It is held on the transport plate 31 by suction or vacuum suction. As shown in FIG. 2, the conveyance belt 55 is composed of a pair of belts that are separated from each other in the Z-axis direction, and is separated from each other in the Z-axis direction on the lower surface (the surface on the −Y side) of the conveyance plate 31. It is fixed to each end part. The width of each belt constituting the conveyor belt 55 is set to such a width that the conveyor belt 55 does not cover the area of the lower surface of the conveyor plate 31 where the recording paper 1 is held.

  The recording sheet 1 fed and held on the transport plate 31 is transported by the transport belt 55 together with the transport plate 31 to the lower side of the paper discharge device 45 in the direction of the arrow X1 (the −X direction). In the course of the conveyance, the printing process and the drying process are sequentially performed on the recording paper 1. The recording paper 1 conveyed to the lower side of the paper discharge device 45 is separated from the conveyance plate 31 by the paper discharge device 45, for example, by being sucked, and is stored in a paper discharge tray in the paper discharge device 45. The transport plate 31 from which the recording paper 1 has been separated is transported by the transport belt 55 in the direction of the arrow X2 (+ X direction) and returned to the lower side of the paper feeding device 46.

  The transport system drive device 44 is mainly configured by an actuator (not shown) such as a motor and a power transmission system. The transport system driving device 44 drives the transport rollers 51 and 52 in accordance with the control from the control unit 90 and rotates them in the direction of the arrow R1 or the arrow R2, thereby moving the transport belt 55 in the direction of the arrow X1 or the arrow X2. Move at a constant transport speed. For example, the control unit 90 selects a speed according to the operation mode of the recording apparatus 100 </ b> A set in advance via an operation unit (not shown) from the plurality of speeds recorded in the storage unit 81. It is set by doing. The transport speed may be different when moving in the direction of the arrow X1 and when moving in the direction of the arrow X2.

  That is, the transport plate 31, the transport system drive device 44, the transport roller 51 (52), and the transport belt 55 are configured to print the recording paper 1 at a predetermined transport speed along a predetermined processing line. 41 and a transport mechanism that transports relatively in the −X direction with respect to a drying device 42A described later. The processing line is a conveyance path in which processing is performed on the recording paper 1 in the order of printing processing and drying processing. Note that the control unit 90 controls the operation of the entire recording apparatus 100A by controlling each unit of the recording apparatus 100A at a predetermined timing in accordance with a software program stored in advance. The control unit 90 also operates as a drying device 42A as will be described later.

  The recording head unit 41 is mainly configured by including inkjet heads 17K, 17C, 17M, 17Y and the like. The inkjet heads 17K, 17C, 17M, and 17Y eject inks 9K, 9C, 9M, and 9Y, respectively, by an inkjet method that is realized by, for example, a piezo method, a thermal method, or an electromagnetic valve method. The inks 9K, 9C, 9M, and 9Y are water-based inks, such as water-based dye ink and water-based pigment ink, of K (black), C (cyan), M (magenta), and Y (yellow), respectively.

  The recording head unit 41 is provided on the upstream side of the processing line with respect to the drying head unit 43A of the drying device 42A. Each inkjet head in the recording head unit 41 is configured to be movable in the Z-axis direction, and each color moves relative to the recording paper 1 in the Z-axis direction in accordance with control from the control unit 90. Each of the water-based inks is ejected to record an image or the like on the recording paper 1.

  In the recording apparatus 100A shown in FIG. 1, the inkjet heads are arranged so that the inks are ejected in the order of the inks 9K, 9C, 9M, and 9Y in the −X direction. May be changed. Further, the type of water-based ink ejected from the recording head unit 41 may be increased or decreased by increasing or decreasing the number of inkjet heads.

  The drying device 42A is a drying device that dries the recording paper 1 on which the liquid adheres to the recording surface (the paper surface of the recording paper 1 on which visual information is recorded, the paper surface on the + Y side in FIG. 1).

  The drying device 42A mainly includes a drying head unit 43A, a first power supply unit 71, a second power supply unit 72, and a control unit 90. The drying head unit 43A is mainly configured by including a light irradiation unit 5 that irradiates infrared rays 6 and electromagnetic induction coils 21 to 23 for heating by an electromagnetic induction heating method. The first power supply unit 71 and the second power supply unit 72 supply power to the drying head unit 43 </ b> A based on the control of the control unit 90. In more detail, the 1st electric power supply part 71 can supply electric power to the light irradiation part 5, and the 2nd electric power supply part 72 parallelly supplies the high frequency electric power with respect to each of the electromagnetic induction coils 21-23. It can be carried out.

  The control unit 90 controls power supply to each of the light irradiation unit 5 and the electromagnetic induction coils 21 to 23. Moreover, the control part 90 can control independently the high frequency power which the 2nd electric power supply part 72 supplies to the electromagnetic induction coils 21-23, respectively, Thereby, the electromagnetic induction coils 21-23 are mutually different high frequency power. And different heating operations can be performed in parallel.

  The drying head unit 43 </ b> A operates in parallel with the light irradiation unit 5 and the electromagnetic induction coils 21 to 23 in accordance with control from the control unit 90, so that the target area 101 ( The ink 10 attached to the recording surface in FIG. 2) and the target area 101 are heated to fix an image or the like on the recording paper 1 for recording. In addition, the light irradiation part 5 and the electromagnetic induction coils 21-23 may be unitized as one component.

  The target area 101 is set to all or a part of the recording paper 1 when the recording paper 1 is a sheet type sheet. In the setting example shown in FIG. 2, the entire area of the recording paper 1 is set as the target area 101. As will be described later, when the recording paper 1 is a roll paper, the control unit 90 normally performs memory management for each piece of complete visual information recorded on the recording paper 1. An area on the target area 101 where the visual information is recorded is set as the target area 101.

  The recording head unit 41 and the drying head unit 43A are respectively arranged on the upstream side and the downstream side of the processing line on which the recording paper 1 is conveyed. Further, the light irradiation unit 5 and the electromagnetic induction coils 21 to 23 in the drying head unit 43A are respectively arranged on the upper side and the lower side of the recording paper 1 that is conveyed along with the conveyance plate 31 along the processing line.

  The light irradiation unit 5 is directed toward the recording surface of the predetermined target area 101 in the recording paper 1 being conveyed relative to the drying head unit 43A of the drying device 42A at a predetermined conveyance speed along the processing line. The ink 10 attached to the recording surface of the target area 101 is heated by irradiating the target area 101 with an infrared ray (also simply referred to as “light”) 6 that crosses the target area 101 in the width direction substantially orthogonal to the processing line. More specifically, the infrared rays 6 applied to the ink 10 on the recording paper 1 are absorbed by the ink 10 to raise the temperature of the ink 10, thereby evaporating moisture contained in the ink 10 and drying the ink 10. .

  The light irradiation unit 5 mainly includes, for example, an infrared radiation tube (infrared source) 3 that radiates infrared rays, and a reflecting mirror 4 that reflects infrared rays radiated from the infrared radiation tube 3 and deflects them in the direction of the transport belt 55. It is prepared for. The infrared radiation tube 3 is a straight tube arranged parallel to the paper surface of the recording paper 1, and the tube length direction is the width direction (Z direction) of the paper surface of the recording paper 1. The infrared radiation directly radiated from the infrared radiation tube 3 toward the recording paper 1 on the conveying belt 55 and the infrared radiation reflected from the reflecting mirror 4 constitute the infrared radiation 6, and the infrared radiation 6 is the recording surface of the recording paper 1. Is irradiated. The infrared rays 6 are preferably irradiated as parallel rays, but even if they are not parallel rays, the usefulness of the present invention is not impaired. Moreover, even if the light irradiation part 5 is mainly comprised only of the infrared radiation tube 3 among the infrared radiation tube 3 and the reflective mirror 4, it does not impair the usefulness of this invention. In addition, since water absorbs infrared rays better than ultraviolet rays and visible light, the light irradiation unit 5 preferably emits infrared rays 6.

  The electromagnetic induction coils 21 to 23 heat the target region 101 by applying heat generated by the electromagnetic induction heating method to the back surface of the recording surface in the target region 101 of the recording paper 1. More specifically, the electromagnetic induction coils 21 to 23 heat the recording sheet 1 held on the conveyance plate 31 by heating the conveyance plate 31 by electromagnetic induction heating. The conveyance plate 31 is configured to include a plate-like conductor having substantially the same size as the conveyance plate 31, for example, iron or cobalt. As shown in FIG. 2, the transport plate 31 is in contact with the back surface over the entire width in the width direction of the back surface of the recording surface in the target area 101 of the recording paper 1. For example, a thin film of a silicone-based resin may be formed on the upper surface of the transport plate 31 so that, for example, the recording paper 1 can be easily peeled off.

  As shown in FIG. 2, the electromagnetic induction coils 21 to 23 are sequentially arranged along the width direction on the back side of the recording surface with respect to the recording paper 1. Thereby, the electromagnetic induction coils 21 to 23 are configured to be able to heat a plurality of preset sections (also referred to as “first sections”) that respectively section the target region 101 along the width direction. . In the example of FIG. 2, the target area 101 is divided into three first sections along the width direction of the target area 101 by boundary lines 111 and 112, and electromagnetic induction is performed with respect to the three first sections. Coils 21 to 23 are respectively disposed. Each boundary line such as the boundary line 111 that defines a plurality of first sections is set between two adjacent electromagnetic induction coils according to the width of each electromagnetic induction coil. Even if the widths of the first sections along the width direction are not equal to each other, the usefulness of the present invention is not impaired.

  The storage unit 81 is configured by a memory, a hard disk drive, and the like, and stores information that defines the target area 101, area information that defines a plurality of block areas 131 into which the target area 101 is partitioned in a lattice shape, and the like. Yes. The stored information is read by the control unit 90 and used for controlling the recording apparatus 100A.

  The control unit 90 is realized by a computer including a CPU, and the CPU executes each software program stored in advance in a memory or the like, thereby controlling each unit of the recording apparatus 100A at a predetermined timing, and operation of the entire recording apparatus 100A. Control. The control unit 90 also operates as a region information acquisition unit 91, a block heat amount acquisition unit 92, a first heat amount acquisition unit 93, a second heat amount acquisition unit 94, and a power control unit 95.

  The area information acquisition unit 91 divides the target area 101 into a plurality of first sections along the width direction, and into a plurality of sections (also referred to as “second sections”) along the processing line. As a result, area information that defines a plurality of block areas 131 divided in a grid pattern is acquired. Specifically, in the example shown in FIG. 2, the target area 101 is divided into three first sections along the width direction of the target area 101 by boundary lines 111 and 112 extending in the processing line direction. The boundary lines 121 to 123 extending in the width direction (Z-axis direction) are divided into four second sections along the processing line. As a result, 12 block areas 131 are set for the target area 101. The width in the processing line direction of the plurality of second sections is such that the time required for the electromagnetic induction coils to pass through each second section is longer than the rise time of the output (effective value) of the electromagnetic induction coils. It is set according to the conveyance speed of the recording paper 1 and the power supplied to the electromagnetic induction coil. Even if the widths of the second sections along the processing line direction are not equal to each other, the usefulness of the present invention is not impaired. The area information 141 defining the plurality of block areas 131 is stored in the storage unit 81 in advance, for example. The region information acquisition unit 91 acquires the region information 141 by reading the region information 141 from the storage unit 81 or the like.

  The block heat quantity acquisition unit 92 requires drying for each of the plurality of block areas 131 based on the image data corresponding to the visual information recorded in the target area 101 and the area information 141 defining the plurality of block areas 131. Each block heat quantity is acquired. The block heat quantity acquisition unit 92 first calculates the ink adhesion area in each block area of the plurality of block areas 131 based on the entire area of each block based on the image data corresponding to the visual information recorded in the target area 101. By dividing or the like, the ink adhesion density corresponding to the ink amount in each block area is calculated. Instead of the ink adhesion area, for example, the amount of ink (moisture amount) ejected to each block region may be used. Also, instead of the ink adhesion density (area density), an index value that is physically or mathematically equivalent to the ink adhesion density (area density) such as the volume density of the adhered ink and the weight density of the adhered ink is adopted. May be.

  For example, in the example shown in FIG. 2, the target region 101 includes regions 10 a and 10 b having different areas where ink is ejected and other regions where ink is not attached. Therefore, in the example of FIG. 2, three levels of ink adhesion density are acquired. When the ink adhesion density is obtained, the block calorie acquisition unit 92 refers to a table or function that defines the relationship between the adhesion density (moisture amount) and the amount of heat required for drying to dry each block area. Obtain the amount of heat required (“block heat”). Such functions and tables are obtained in advance by experiments, simulations, etc., and stored in the storage unit 81. As the amount of heat required for drying, for example, the amount of heat required for drying the recording paper 1 without causing wrinkles is employed.

  FIG. 3 is a diagram illustrating the relationship between the amount of moisture in a predetermined area of the recording paper 1 and the amount of heat required for drying. As shown in FIG. 3, the amount of water in the region and the amount of heat required for drying are not proportional to each other, and paper and the like are hydrogen bonded to water. This is because the amount of heat required to dry the powder increases. Therefore, the relationship of the required heat amount with respect to the moisture amount (ink adhesion density) is usually obtained by experiments, simulations using numerical models, and the like.

  The first heat quantity acquisition unit 93 supplies the light irradiation unit 5 uniformly over a predetermined area over the entire area of the target area 101 based on the plurality of block heat quantities acquired respectively corresponding to the plurality of block areas 131. Get the amount of heat. Specifically, for example, the first heat quantity acquisition unit acquires, as the first heat quantity, the minimum value among the heat quantities per predetermined area for the plurality of block heat quantities respectively corresponding to the plurality of block regions 131. If the minimum value is acquired as the first amount of heat, the amount of heat that can be dried without causing wrinkles is generated between the light irradiation unit 5 and the plurality of electromagnetic induction coils even for the block region having the smallest necessary amount of heat per predetermined area. Are supplied only from the light irradiation unit 5. For the other block regions, the amount of heat that is insufficient with only the amount of heat supplied from the light irradiation unit 5 is supplied from the electromagnetic induction coil with good response. Thereby, the improvement of responsiveness and suppression of overdrying can be made compatible.

  The second heat quantity acquisition unit 94 acquires the heat quantity supplied by the light irradiation unit 5 acquired by the first heat quantity acquisition unit 93 for each of the plurality of block regions 131 based on the first heat quantity. Then, the second heat quantity acquisition unit 94 acquires the remaining heat quantity obtained by subtracting the acquired heat quantity from the block heat quantity acquired by the block heat quantity acquisition unit 92 as the second heat quantity supplied by the plurality of electromagnetic induction coils 21 to 23.

  The power control unit 95 supplies the first heat amount evenly per predetermined area over the entire area of the target region 101, and the power control unit 95 supplies a plurality of corresponding second heat amounts to the plurality of block regions 131. The first power supply unit and the second power supply unit are respectively controlled so that the corresponding coils among the electromagnetic induction coils are supplied. Specifically, the power control unit 95 obtains power to be supplied to the light irradiation unit 5 from the first heat amount, the area of the target region 101, and the conveyance speed of the recording paper 1, for example. In addition, the power control unit 95 corresponds to each block among the plurality of electromagnetic induction coils during the period in which each block area is heated based on the second heat amount, the area of each block, and the conveyance speed of the recording paper 1. The electric power to be supplied by the coil is determined. These electric powers are acquired by calculation or table reference. When the power to be supplied is acquired, the power control unit 95 supplies the acquired power to the light irradiation unit 5 and the plurality of electromagnetic induction coils as the recording paper 1 is conveyed.

  FIG. 4 is a diagram for explaining a process for improving the output responsiveness of the electromagnetic induction coils 21 to 23. FIG. 4 illustrates a control signal 301, an output 302, a control signal 303, an output 304, and a reference output 305 over time. The signal supply time T1 is a time required for the electromagnetic induction coil to pass through one target block area among the plurality of block areas 131. The control signals 301 and 303 are examples of control signals that the control unit 90 supplies to the second power supply unit 72 over the signal supply time T1, and the output 302, the output 304, and the reference output 305 are output according to the control signals. The output of the electromagnetic induction coil with respect to the high frequency electric power which 2 electric power supply part 72 supplies is shown. The second power supply unit 72 supplies high-frequency power of power corresponding to the signal value of the control signal supplied from the control unit 90 to the electromagnetic induction coil. FIG. 4 shows the response characteristics of the electromagnetic induction coil for the block area of interest among the plurality of block areas 131.

  The control signal 301 is a rectangular signal having a signal value S1, and the output 302 corresponding to the control signal 301 is an output having the output value P1 as a peak. As shown in output 302, rise time t1 occurs. In addition, a fall time also occurs at the fall from the output value P1. The rise (fall) time is caused by the influence of a time constant.

  Therefore, a control signal 303 is supplied to shorten the rise time t1. In the control signal 303, a signal having a signal value S 2 larger than the signal value S 1 is supplied only during the initial time (period) of the signal supply time T 1, and thereafter, similarly to the control signal 301, a signal having the signal value S 1 is supplied. . As shown in FIG. 4, the output 304 for the control signal 303 has a rise time t <b> 2, which is shorter than the rise time t <b> 1 at the output 302. The reference output 305 shows the output until the output of the electromagnetic induction coil reaches a stable output value P2 when the rectangular wave of the signal value S2 is supplied over the signal supply time T1 as in the control signal 301. . The necessary output value P1 is obtained before reaching the output value P2. Instead of supplying the control signal 301 having the signal value S1 corresponding to the required output value P1, the control signal 301 having a signal value larger than the required signal value S1 is supplied only during a part of the initial period. Time is shortened.

  Specifically, the power control unit 95 determines that the heat quantity per unit area of the second heat quantity for the target block area among the plurality of block areas 131 is one block downstream of the processing line with respect to the target block area. Is larger than the amount of heat per unit area of the second heat amount, the constant coil required to heat the region of interest among the plurality of electromagnetic induction coils to supply the second amount of heat corresponding to the block region of interest. To supply high frequency power having a larger effective value than the high frequency power of the effective value to the corresponding electromagnetic induction coil over the initial part of the period in which the target block region is heated by the corresponding electromagnetic induction coil, The second power supply unit 72 is controlled. By this control, the rise time required for the rise of the output of the electromagnetic induction coil is shortened, and the response of the output of the electromagnetic induction coil is further improved.

<A-2. Operation of the drying device>
FIG. 5 is a flowchart illustrating an example of the operation of the drying device 42A according to the embodiment. FIG. 5 shows the operation of the control unit 90 among the operations of the drying device 42A.

  First, the region information acquisition unit 91 acquires region information 141 that defines a plurality of block regions 131 (step S110), and the block heat amount acquisition unit 92 performs block heat amount required for drying for each block region of the plurality of block regions 131. Are acquired (step S120). Next, the first heat quantity acquisition unit 93 acquires the first heat quantity that the light irradiation unit 5 supplies uniformly over a predetermined area over the entire target region 101 (step S130), and the second heat quantity acquisition unit 94 receives the first heat quantity. The second heat quantity supplied by the electromagnetic induction coils 21 to 23 based on the one heat quantity is acquired (step S140).

  Next, as described above with reference to FIG. 4, the power control unit 95 performs an improvement process necessary for improving the responsiveness of the electromagnetic induction coil 21 (step S150). Note that the processing in step S150 is unnecessary when necessary responsiveness can be obtained even when the conveyance speed is low and the improvement processing is not performed. Therefore, even if the process of step S150 is not performed, the usefulness of the present invention is not impaired.

  Next, the power control unit 95 controls the first power supply unit 71 and the second power supply unit 72 (step S160), and operates the light irradiation unit 5 and the plurality of electromagnetic induction coils, thereby recording sheet 1 The drying process is performed (step S170).

  According to the drying apparatus according to the embodiment configured as described above, the target area 101 of the recording paper 1 to which the liquid has adhered is partitioned along both the width direction and the processing line to form a lattice shape. For each of the plurality of divided block regions 131, the amount of block heat required for drying is acquired. A first amount of heat supplied by the light irradiation unit 5 per predetermined area based on each block heat amount is acquired, and a second amount of heat supplied by the electromagnetic induction coil among the block heat amounts of each block region based on the first amount of heat. Is acquired. And the heating by the electric power supply according to the acquired heat amount is performed by the light irradiation part 5 and an electromagnetic induction coil. That is, for each block region in which the target region 101 is divided into a grid, the amount of heat required for heating is distributed to the light irradiation unit and the electromagnetic induction coil having better responsiveness than the light irradiation unit, and both are heated. Done. Thereby, it is possible to supply a larger amount of heat to the recording paper 1 than when only one of the light irradiation unit 5 and the electromagnetic induction coil is used, and compared with the case where only the light irradiation unit 5 is used. Good responsiveness is realized in both the width direction and the processing line direction. Therefore, even when the fluctuation range of the density of the liquid adhering to the recording paper 1 in the width direction and the processing line direction of the recording paper 1 is large and the conveyance speed is high, the recording paper 1 is dried at high speed while suppressing drying unevenness. it can.

  Further, according to the drying apparatus according to the embodiment configured as described above, the first heat quantity acquisition unit, for example, of each heat quantity per predetermined area for a plurality of block heat quantities respectively corresponding to the plurality of block regions 131. The minimum value is acquired as the first heat quantity. If the minimum value is acquired as the first amount of heat, the amount of heat that can be dried without causing wrinkles is generated between the light irradiation unit 5 and the plurality of electromagnetic induction coils even for the block region having the smallest necessary amount of heat per predetermined area. Are supplied only from the light irradiation unit 5. For the other block regions, the amount of heat that is insufficient with only the amount of heat supplied from the light irradiation unit 5 is supplied from the electromagnetic induction coil with good response. Therefore, both improvement in responsiveness and suppression of overdrying can be achieved.

  Further, according to the drying apparatus according to the embodiment configured as described above, the heat quantity per unit area of the second heat quantity for the target block area among the plurality of block areas 131 is a processing line with respect to the target block area. When the heat quantity per unit area of the second heat quantity for one block area on the downstream side is larger than the heat quantity per unit area, the corresponding coil that heats the attention area among the plurality of electromagnetic induction coils corresponds to the second heat quantity corresponding to the attention block area. The high-frequency power having an effective value larger than the fixed effective high-frequency power required to supply the target electromagnetic field over the initial partial period of the period in which the target block region is heated by the corresponding electromagnetic induction coil The second power supply unit 72 is controlled so as to be supplied to the induction coil. By this control, only the initial value of the block heating period gives an electric power with an effective value larger than the effective value necessary to give the required output, so that the rise time required for the rise of the output of the electromagnetic induction coil is further shortened. Thus, the response of the output of the electromagnetic induction coil is further improved.

<B. Modification>
Although the invention has been shown and described in detail, the above description is illustrative in all aspects and not restrictive. Therefore, embodiments of the present invention can be modified or omitted as appropriate within the scope of the invention. For example, when roll paper is used as the recording paper 1, a cylindrical transport plate 31 that is in contact with the recording paper 1 transported along the processing line is employed, and the cylindrical target axis direction is provided inside the transport plate 31. By adopting the configuration in which the electromagnetic induction coils 21 to 23 are arranged along the same, a drying process similar to the process performed by the drying head unit 43A is performed. In this case, since the control unit 90 performs memory management for each piece of complete visual information recorded on the recording paper 1, for example, an area on the target area 101 where the visual information is recorded is the target area 101. Set as

1 Recording paper (recording medium)
DESCRIPTION OF SYMBOLS 100A Recording apparatus 42A Drying apparatus 43A Drying head part 5 Light irradiation part 21-23 Electromagnetic induction coil 90 Control part 91 Area | region information acquisition part 92 Block calorie | heat amount acquisition part 93 1st calorie | heat amount acquisition part 94 2nd calorie | heat amount acquisition part 95 Power control part

Claims (5)

A drying apparatus for drying a recording medium on which a liquid adheres to a recording surface,
The target region is moved to the processing line toward the recording surface of a predetermined target region of the recording medium that is transported relative to the drying device at a predetermined transport speed along a predetermined processing line. A light irradiation unit that heats the liquid adhering to the recording surface of the target region by irradiating light that crosses in a substantially orthogonal width direction;
A first power supply unit for supplying power to the light irradiation unit;
A plurality of electromagnetic induction coils for heating the target area of the recording medium by applying heat generated by an electromagnetic induction heating method to the back surface of the recording surface of the target area;
A second power supply unit that supplies high-frequency power to each of the plurality of electromagnetic induction coils;
A control unit for controlling power supply to each of the light irradiation unit and the plurality of electromagnetic induction coils;
With
The plurality of electromagnetic induction coils are:
Sequentially along the width direction on the back surface side of the recording surface with respect to the recording medium so as to heat each of a plurality of preset first sections that respectively divide the target area along the width direction. Arranged in
The controller is
The target area is divided into the plurality of first sections along the width direction, and is divided into a plurality of second sections along the processing line, so that a plurality of blocks partitioned in a lattice shape An area information acquisition unit for acquiring area information defining the area;
A block calorie acquisition unit that respectively acquires a block calorie required for drying for each of the plurality of block regions based on the image data corresponding to the visual information recorded in the target region and the region information;
Based on a plurality of block heat amounts corresponding to the plurality of block regions, respectively, a first heat amount acquisition unit that acquires a first heat amount that the light irradiation unit uniformly supplies per predetermined area over the entire target region;
For each of the plurality of block regions, the amount of heat supplied by the light irradiation unit is acquired based on the first amount of heat, and the plurality of electromagnetic induction coils supplies the remaining amount of heat obtained by subtracting the acquired amount of heat from the block heat amount. A second heat quantity acquisition unit that acquires the second heat quantity
The light irradiation unit uniformly supplies the first amount of heat per predetermined area over the entire target region, and supplies the corresponding second amount of heat to the plurality of electromagnetic inductions for each of the plurality of block regions. A power control unit for controlling each of the first power supply unit and the second power supply unit so that a corresponding coil of the coils supplies the power supply unit;
A drying apparatus comprising: The drying apparatus according to claim 1,
The first heat quantity acquisition unit
A drying apparatus that acquires, as the first heat amount, a minimum value among the heat amounts per predetermined area for the plurality of block heat amounts respectively corresponding to the plurality of block regions. The drying apparatus according to claim 1 or 2,
The power control unit
The amount of heat per unit area of the second heat amount for the target block region among the plurality of block regions is a unit of the second heat amount for the block region downstream of the processing line with respect to the target block region. If it is greater than the amount of heat per area,
Among the plurality of electromagnetic induction coils, high frequency power having an effective value larger than a constant effective high frequency power required for a corresponding coil that heats the target region to supply the second amount of heat corresponding to the target block region. The drying device that controls the second power supply unit so that the block area of interest is supplied to the corresponding coil over a part of the initial period during which the target block area is heated by the corresponding coil. A drying apparatus according to any one of claims 1 to 3,
A transport mechanism for transporting the recording medium relative to the drying device at the transport speed along the processing line;
A recording head provided on the upstream side of the processing line with respect to the drying device, and recording visual information on the recording medium by discharging the liquid;
A printing apparatus comprising: A drying method for drying a recording medium having a liquid attached to a recording surface by a drying device,
The drying device
The target region is moved to the processing line toward the recording surface of a predetermined target region of the recording medium that is transported relative to the drying device at a predetermined transport speed along a predetermined processing line. A light irradiation unit that heats the liquid adhering to the recording surface of the target region by irradiating light that crosses in a substantially orthogonal width direction;
A first power supply unit for supplying power to the light irradiation unit;
A plurality of electromagnetic induction coils for heating the target area of the recording medium by applying heat generated by an electromagnetic induction heating method to the back surface of the recording surface of the target area;
A second power supply unit that supplies high-frequency power to each of the plurality of electromagnetic induction coils;
A control unit for controlling power supply to each of the light irradiation unit and the plurality of electromagnetic induction coils;
With
The plurality of electromagnetic induction coils are:
Sequentially along the width direction on the back surface side of the recording surface with respect to the recording medium so as to heat each of a plurality of preset first sections that respectively divide the target area along the width direction. Arranged in
The drying method is
The target area is divided into the plurality of first sections along the width direction, and is divided into a plurality of second sections along the processing line, so that a plurality of blocks partitioned in a lattice shape An area information acquisition step for acquiring area information defining the area;
A block heat quantity obtaining step for obtaining a block heat quantity required for drying for each of the plurality of block areas based on the image data corresponding to the visual information recorded in the target area and the area information;
A first heat quantity obtaining step for obtaining a first heat quantity that the light irradiation unit uniformly supplies per predetermined area over the entire area of the target area, based on the plurality of block heat quantities respectively corresponding to the plurality of block areas;
For each of the plurality of block regions, the amount of heat supplied by the light irradiation unit is acquired based on the first amount of heat, and the plurality of electromagnetic induction coils supplies the remaining amount of heat obtained by subtracting the acquired amount of heat from the block heat amount. A second heat quantity acquisition step of acquiring as a second heat quantity to be performed;
The light irradiation unit supplies the first amount of heat per predetermined area of the target region, and the corresponding second amount of heat corresponds to each of the plurality of block regions among the plurality of electromagnetic induction coils. A power control step for controlling the first power supply unit and the second power supply unit, respectively, so that the coils to be supplied are,
A drying method comprising:

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