JP2010096441A - Method and device of drying ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly and properly dry print ink without using hot air. <P>SOLUTION: This ink drying device is used for drying print ink i transferred to a belt-shaped printed base material P. This ink drying device includes a guide roller 35 supporting the printed base material P transferrably in the longitudinal direction, an infrared ray heater unit 36 having a plurality of heating elements 36 radiating near infrared ray of wavelength of 0.78-2.5 μm, and movable between a first position close to a printed face Pa of the base material P and a second position separating from the printed face Pa, a heating quantity adjusting section 37 for adjusting the heating quantity of each heating element 36b, and a fluid pressure cylinder for moving the infrared ray heater unit 36 from the first position to the second position when the transferring of the printed board in the longitudinal direction is stopped. The base material P and the infrared ray heater unit 36 are relatively moved at a constant speed in a state of keeping a constant distance between the printed face Pa and the infrared ray heater unit 36, while irradiating the printed face Pa of the base material P with near infrared ray. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technique for drying printing ink, and more particularly to a method and apparatus capable of drying printing ink immediately after printing.

  Inks are classified into printing inks, writing inks, special inks, etc., depending on the application. Of these, printing inks are roughly classified into letterpress inks, intaglio inks, and lithographic inks according to the type of printing plates. These printing inks are made by dispersing or dissolving a coloring material such as a pigment or dye in a medium (vehicle) as a main agent, and adding an auxiliary agent as necessary.

  As the color material, a dye is used only in a case where transparency is required in flexography or in a special case such as cloth printing, but a pigment is generally used. Pigments include inorganic pigments and organic pigments, with black being typically carbon black and white being titanium white.

  The medium is composed of a binder that can be a solid component and a solvent (solvent) for imparting fluidity to the medium. Mineral oil is mainly used for letterpress ink, and natural resin such as modified rosin is used for intaglio ink. Alternatively, a synthetic resin such as modified nitrocellulose or alkyd resin dissolved in a low boiling point solvent such as alcohol or hydrocarbon is used. In lithographic ink, oil varnish and synthetic resin varnish are mainly used.

  On the other hand, the auxiliary agent is generally classified into a drying accelerator (dryer) that accelerates drying of the ink and a printing effect modifier such as a wax or a surfactant that adjusts the fluidity and gloss of the ink.

  Here, according to the printing ink as described above, even if a drying accelerator is included as an auxiliary agent, if the printing surface is overlapped immediately after printing, the printing ink is transferred to another substrate to be printed. Or images and characters displayed by the printing ink may be disturbed and the printed surface may be soiled.

For this reason, after printing on a printing substrate using printing ink, it is generally widely practiced to pass the printing substrate through a hot air dryer to dry the printing ink with hot air (for example, patents). Literature 1, 2, 3)
JP-A-8-118602 (Claims, FIG. 1) Japanese Patent Laying-Open No. 2005-308377 (Claims, FIG. 1) JP 2000-238402 A (paragraph 0026)

  However, in the hot air drying method, dust contained in the air may adhere to undried printing ink and cause pinholes. Since such a printed matter is treated as a defective product and cannot be shipped as a product, if the defect occurrence rate increases, a large damage will occur. In addition, the hot air dryer takes time to warm up for raising the temperature to a predetermined temperature, consumes a lot of energy, and is generally large in size and high in cost. There are many traders.

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a method capable of quickly and satisfactorily drying printing ink without using hot air, and a simple drying apparatus. There is.

In order to achieve the above object, the present invention
After printing by transferring printing ink to the printing substrate, the printing surface and the infrared heater while irradiating the printing surface of the printing substrate with near infrared rays having a wavelength of 0.78 to 2.5 μm from the infrared heater unit. There is provided an ink drying method characterized by relatively moving the substrate to be printed and the infrared heater unit at a constant speed while maintaining a constant distance from the unit.

  An ink drying apparatus used for drying the printing ink transferred to the belt-shaped printing substrate, the substrate guide supporting the printing substrate so as to be transportable in the length direction thereof, and a wavelength of 0 A plurality of heating elements that emit near-infrared rays of 78 to 2.5 μm, and move between a first position close to the printing surface of the substrate to be printed and a second position separated from the printing surface; A possible infrared heater unit, a calorific value adjusting means for adjusting the calorific value of each heating element, and when the transfer of the substrate to be printed in the length direction is stopped, the infrared heater unit is moved to the first position. Unit moving means for moving from to the second position.

In addition, each heating element of the infrared heater unit is a tube having a predetermined length,
The infrared heater unit is characterized in that each heating element is arranged so as to be orthogonal to a transfer path of the substrate to be printed.

  According to the present invention, while irradiating near infrared rays having a wavelength of 0.78 to 2.5 μm from the infrared heater unit to the printing surface of the substrate to be printed on which the printing ink has been transferred, the printing surface and the infrared heater unit Since the substrate to be printed and the infrared heater unit are relatively moved at a constant speed while keeping the distance constant, the printing ink can be dried by heating the printing ink by radiant heat from near infrared rays. In particular, compared to the method in which hot air is blown, there is less risk of pinholes due to adhesion of dust to undried printing ink, and not only the surface of the printing ink but also the transmission of the printing ink by the near infrared surface transmission. Since the inside is directly heated, the printing ink can be dried immediately, and the entire printing ink can be uniformly heated and dried as compared with the hot air drying method.

  In addition, the near-infrared radiant heat type drying device can be downsized compared to the hot air type drying device, and the infrared heater unit can start up to a predetermined temperature in a very short time. It is possible to prepare quickly for preparation.

  Furthermore, according to the ink drying apparatus according to the present invention, when the transfer of the substrate to be printed is stopped, the infrared heater unit is configured to be separated from the printing surface of the substrate to be printed. It is possible to prevent discoloration or heat loss of the printing ink due to excessive irradiation of the printing ink.

  In addition, since a calorific value adjusting means for adjusting the calorific value of each heating element is provided, the near-infrared irradiation intensity can be adjusted to an optimum state according to the type of printing ink.

  In addition, since the infrared heater unit has a tubular heating element disposed so as to be orthogonal to the transfer path of the substrate to be printed, the printing ink is irradiated with near infrared rays uniformly. Can be heated and dried uniformly.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic front view showing a usage mode of an ink drying apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a base material supply unit. The base material supply unit 1 is a rotary drum type, and a base material roll R1 is mounted on the rotary shaft 1a, and the base material to be printed is fed out from the base material roll R1. P is configured to be wound as a product roll R2 on the substrate winding unit 4 through the printing press 2 and the ink drying device 3 according to the present invention. The substrate P to be printed is a cloth (band cloth) continuous in a band shape, and one side (the upper surface in FIG. 1) is printed by the printing machine 2 to be a printing surface Pa.

  The printing machine 2 is, for example, a rotary letterpress printing machine, and is installed upstream of the ink drying apparatus 3 in the transport direction of the substrate P to be printed. Reference numeral 21 denotes a plate cylinder constituting the printing machine 2, and a printing plate 21a (a relief plate) is fixed to the outer peripheral surface thereof, and the impression cylinder 22 is pressed against the printing plate 21a via a printing substrate P. ing. Further, the ink roll 23 comes into contact with the printing plate 21a, and the printing ink i is transferred from the ink roll 23 to the printing pattern formed on the printing plate 21a. For this reason, the printing ink i is transferred in a predetermined printing pattern to the printing substrate P passed between the plate cylinder 21 and the impression cylinder 22. And the to-be-printed base material P with which printing was performed is introduce | transduced into the ink drying apparatus 3 located downstream of the printing machine 2, and, thereby, the printing ink i is heat-dried.

  The ink drying device 3 has a caster 32 at the bottom of the main body frame 31 as a portable type, and the caster 32 rolls and contacts the installation surface with the reduction of the fixing leg 33. Further, guide rollers 35 (base material guides) are provided on the left and right sides of the main body frame 31 via brackets 34, and the length of the base material P to be printed that has passed through the printing machine 2 by the guide rollers 35 and 35 is the length. It is configured to be supported so as to be transportable in the direction.

  An infrared heater unit 36 is disposed in the main body frame 31 on the transfer path of the printing substrate P supported by the guide rollers 35, 35, and the printing substrate P has a printing surface Pa below it. Passes upward.

  In the infrared heater unit 36, a plurality of (11 in the illustrated example) heating elements 36b that emit near infrared rays having a wavelength of 0.78 to 2.5 μm are mounted in parallel on a unit base 36a formed of a metal plate or the like. Configured. The unit base 36a includes a reflector (not shown) that covers the heat generating elements 36b,... So that near infrared rays emitted from the heat generating elements 36b are directed toward the printing surface Pa of the substrate to be printed. Reflected.

  In FIG. 1, reference numeral 37 denotes a heat amount adjusting unit (heat amount adjusting means) having an operation element (slidable) for adjusting the heat generation amount of each heating element 36 b, and the heat amount adjusting unit 37 and the infrared heater unit 36 are electrically connected. Connected, the amount of power applied to each heating element 36b can be adjusted by the operation of the heat quantity adjusting unit 37, and the amount of heat generated by these heating elements 36b can be individually adjusted. As a result, the irradiation intensity of near infrared rays on the printing surface Pa is It is supposed to be variable.

  Next, FIG. 2 shows the state which looked at the ink drying apparatus from the side. In FIG. 2, reference numeral 38 denotes a support mechanism for supporting the infrared heater unit 36. The support mechanism 38 includes a bush 38a fixed to the main body frame 31 and a slide shaft 38b that is slidable in the vertical direction and is passed through the bush 38a. In addition, each end (lower end) of the slide shaft 38b is connected by a movable base 38c. A pair of left and right arms 38d extending in the horizontal direction is fixed to the other end (upper end) of the slide shaft 38b (two on the left and right), and an infrared heater unit 36 is attached to the tip of the arm 38b. It has been.

  Thereby, the infrared heater unit 36 has a first position indicated by a solid line in FIG. 2 (position close to the printing surface Pa of the substrate P to be printed) and a second position indicated by a one-dot chain line in FIG. And a position separated from the printing surface Pa of the substrate P).

  Reference numeral 39 denotes an actuator (unit moving means) that moves the infrared heater unit 36 between the first position and the second position. In this example, a fluid pressure cylinder (air cylinder) is used. The fluid pressure cylinder 39 is fixed to the lower part of the main body frame 31 in an upright state, and its telescopic rod 39a is connected to the movable base 38c. Therefore, the infrared heater unit 36 can be moved between the first position and the second position by driving the fluid pressure cylinder 39 to extend and contract. In particular, a sensor (for example, a reflective photoelectric switch) (not shown) that detects whether or not the substrate P to be printed is being transferred is attached to the main body frame 31, and the substrate to be printed is based on the output signal. When it is determined that the transfer of P is stopped, the fluid pressure cylinder 39 extends to move the infrared heater unit 36 from the first position to the second position, and the infrared rays until the transfer of the substrate P to be printed is started. The heater unit 36 is held in the second position. According to this, discoloration and heat loss due to excessive printing of near infrared rays from the infrared heater unit 36 by the printing substrate P and the printing ink i can be prevented.

  As is clear from FIG. 2, the heating element 36b of the infrared heater unit 36 has a tubular shape having a predetermined length. In this example, a tungsten lamp in which a tungsten wire is sealed as a heater element in a glass tube is used for the heating element 36b.

As is apparent from FIG. 3, the infrared heater unit 36 as described above has a transfer path of the printing substrate P (the length direction of the printing substrate P spanned between the pair of left and right guide rollers 35, 35). L), the heating elements 36b are arranged so as to be orthogonal to each other. According to this, near infrared rays having a wavelength of 0.78 to 2.5 μm are uniformly applied to the printing surface Pa of the substrate P to be printed that passes directly under the infrared heater unit 36 (the irradiation intensity is the printing ink). Although it differs depending on the type of i, it is generally 70 to 110 mW / cm ² ), and the printing ink i on the printing surface Pa can be uniformly heated and dried by the radiant heat.

Next, a method for drying printing ink using the ink drying apparatus 3 configured as described above will be described. First, a substrate roll R1 formed by winding the substrate to be printed P in a roll shape is set in the substrate supply unit 1, and the substrate to be printed P pulled out from the substrate roll R1 is connected to the inside of the printing press 2 and the ink. It extends to the substrate take-up unit 4 via the guide rollers 35 and 35 of the drying device 3, and the leading end of the substrate P to be printed is locked to the substrate take-up unit 4. Thereafter, the substrate winding unit 4 is rotationally driven to pull out the substrate P to be printed from the substrate roll R1 by a certain amount, and is transferred to the printing machine on one side while being transported at a constant speed in the length direction without sagging. In step 2, the printing ink i is transferred in a predetermined printing pattern, and printing is performed sequentially. At this time, the infrared heater unit 36 of the ink drying device 3 located downstream is placed at the first position close to the printing surface Pa of the substrate P to be printed, and each heating element 36b has a predetermined heating value (printing target). The near-infrared irradiation intensity with respect to the printing surface Pa of the substrate P is set in advance by the calorific value adjustment unit 37 so that the irradiation intensity is 70 to 110 mW / cm ² .

  Therefore, from the infrared heater unit 36 to the printing surface Pa of the printing substrate P that is transferred at a constant speed while the printing surface Pa of the printing substrate P and the infrared heater unit 36 are kept at a certain close distance. Near infrared rays having a wavelength of 0.78 to 2.5 μm are irradiated. In particular, even if a part of the near-infrared ray irradiated to the printing ink i is reflected, most of it is transmitted through the surface of the printing ink i and absorbed therein. For this reason, the printing ink i on the printing surface Pa is heated from the inside by radiant heat by near infrared rays, and the solvent component is promoted to volatilize and evaporate. 10 seconds).

  The present invention can be applied to various printing inks. In this example, as the printing ink i, a pigment is dispersed in a vehicle in which a silicone ink that is difficult to dry, for example, a silicone resin as a fixing agent, is dissolved in a solvent. Things are used.

  The application examples of the present invention have been described above, but the present invention is not limited to the above examples. For example, in the above example, a tungsten lamp is used as the heating element 36b, but a halogen lamp or the like may be used for this. In the above example, eleven heating elements 36b are arranged in parallel, but this can be increased or decreased as necessary.

  Furthermore, in the above example, the substrate P to be printed moves relative to the infrared heater unit 36. However, the infrared heater unit 36 moves along the printing surface Pa while fixing the substrate P to be printed. You may do it.

Schematic front view showing how the ink drying apparatus according to the present invention is used Side schematic diagram of the ink dryer Plan view showing the positional relationship between the infrared heater unit and the substrate to be printed

Explanation of symbols

P substrate to be printed Pa printing surface i printing ink 2 printing machine 3 ink drying device 35 guide roller (substrate guide)
36 Infrared heater unit 36b Heating element 37 Calorie adjustment part (calorie adjustment means)
39 Fluid pressure cylinder (unit moving means)

Claims (3)

After printing by transferring printing ink to the printing substrate, the printing surface and the infrared heater while irradiating the printing surface of the printing substrate with near infrared rays having a wavelength of 0.78 to 2.5 μm from the infrared heater unit. An ink drying method characterized by relatively moving the substrate to be printed and the infrared heater unit at a constant speed while maintaining a constant distance from the unit. An ink drying apparatus used for drying printing ink transferred to a band-shaped printing substrate, a substrate guide for supporting the printing substrate so as to be transportable in the length direction thereof, and a wavelength of 0.78 A plurality of heating elements that emit near-infrared rays of up to 2.5 μm and movable between a first position close to the printing surface of the substrate to be printed and a second position spaced apart from the printing surface; An infrared heater unit, a heat amount adjusting means for adjusting the heat generation amount of each heating element, and the infrared heater unit from the first position when the transfer of the substrate to be printed in the length direction is stopped. An ink drying apparatus comprising: unit moving means for moving to two positions; Each heating element of the infrared heater unit is tubular having a predetermined length,
The ink drying apparatus according to claim 2, wherein the infrared heater unit is arranged such that each heating element is orthogonal to a transfer path of the substrate to be printed.

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