JP2018171722A - Image recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image recorder that has a constitution for preventing deformation of a recording medium from occurring in a nonprint part during drying of a long recording medium.SOLUTION: An image recorder includes: a transfer unit for continuously conveying a long recording medium; an image recording part for recording an ink image based on image dara in the recording medium conveyed by the transfer unit; a dry part having a plurality of heating chambers for heating and drying the ink image recorded in the recording medium by the image recording part; and conveyance distance changing means for changing a between-heating chamber conveyance distance of the recording medium among the plurality of heating chambers.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image recording apparatus that records an ink image while conveying a long recording medium.

  In an inkjet printing apparatus that prints on a continuous long recording medium, printing is performed by ejecting ink from a plurality of inkjet nozzles onto a recording medium that is supported and conveyed by a plurality of rollers. In a printing apparatus provided with a plurality of rollers in the conveyance path of the recording medium, when conveying the recording medium after printing, there is a problem in that the ink is transferred to the roller in contact with the printing surface and the printed matter is stained. It becomes. For this reason, in order to prevent the occurrence of such a printing defect, a printing apparatus including a drying unit for drying ink immediately after printing has been proposed.

  As the drying means, drum drying by warming the drum, radiation drying by drying by applying a halogen lamp or an infrared heater, hot air drying by blowing hot air, etc. are mainly used. Such a drying process corresponds to a fixing process in electrophotography, and loses the merit of ink-jet technology that has been consuming low energy. Therefore, it is desirable to realize drying with as low energy consumption as possible.

  The object to be dried is ink, and heating of components such as paper and rollers causes unnecessary energy consumption. Examples of means for selectively drying only ink include means utilizing friction loss of dielectric dipoles such as microwaves and high frequency dielectrics. This is because the amount of heat generation depends on the dielectric constant and tangent loss of the dielectric, and water shows an extremely high value. Therefore, in a medium on which an image is formed with ink, the medium is not heated, and only the moisture of the ink is heated. Furthermore, since only the amount of heat that is heated becomes a power loss in high-frequency electrolysis, it is overwhelmingly superior in terms of energy efficiency.

JP 2008-179107 A

  In the apparatus described in Patent Document 1, the amount of microwave heating by the microwave heating mechanism is controlled based on the dry state of the paper (recording medium) detected by the detection unit, and the paper is dried. However, when the microwave heater is used for drying, the paper (recording medium) is rapidly heated. Therefore, when the amount of microwave heating obtained based on the dry state is large, the paper (recording medium) is heated rapidly, the temperature rises, and the moisture contained in the non-printed portion of the paper (recording medium) is also stripped. It will evaporate. Even when the amount of microwave heating obtained based on the dry state is small, the water contained in the paper (recording medium) does not evaporate, but the ink is insufficiently evaporated, resulting in insufficient drying. .

  In order to solve the problem of Patent Document 1, a configuration in which a plurality of microwave heating mechanisms is provided is conceivable. However, with this configuration, although the drying deficiency can be solved, the temperature of the paper (recording medium) rises due to no consideration of cooling the paper, and the moisture contained in the non-printed portion of the paper (recording medium) Evaporation occurs.

  When the moisture contained in the non-printed part of the paper (recording medium) evaporates, the paper (recording medium) is deformed, such as curls or seaweed undulations, resulting in poor conveyance or defective printing in the subsequent process, or It becomes a factor that causes defects in the bookbinding process.

  Accordingly, in view of the above problems, the present invention provides an image recording apparatus having a configuration that prevents deformation of a recording medium caused by evaporation of moisture contained in a non-printing portion even when drying by heat treatment is performed on the recording medium. The purpose is to provide.

  In order to solve the above problems, in the image recording apparatus according to the first aspect, a transport unit that continuously transports a long recording medium, and image data for the recording medium transported by the transport unit Between the plurality of heating chambers, an image recording unit for recording an ink image based on the above, a drying unit having a plurality of heating chambers for heating and drying the ink image recorded on the recording medium by the image recording unit, and the heating chamber Transport distance changing means for changing the transport distance of the recording medium between the chambers.

  An image recording apparatus according to a second aspect is the image recording apparatus according to the first aspect, wherein the transport distance changing means moves the heating chamber in a direction along a transport direction of the recording medium. It has a chamber moving mechanism.

  An image recording apparatus according to a third aspect is the image recording apparatus according to the first or second aspect, wherein the transport distance changing means is at least two in the transport path between the plurality of heating chambers. A fixed roller disposed in contact with one main surface of the recording medium, and disposed in the transport path between the fixed rollers, in contact with the other main surface of the recording medium and orthogonal to the transport direction of the recording medium And a movable roller that is movable in the direction of movement.

  An image recording apparatus according to a fourth aspect is the image recording apparatus according to any one of the first to third aspects, wherein the transport distance changing means includes the type of the recording medium, the transport speed, and the ink. The conveyance distance between the plurality of heating chambers is determined according to at least one of image density and ink type.

  An image recording apparatus according to a fifth aspect is the image recording apparatus according to any one of the first to fourth aspects, wherein the heating chamber heat-drys the ink image recorded on the recording medium. A microwave heater is provided.

  With the image recording apparatus according to any of the first to fifth aspects, it is possible to suppress deformation of the recording medium such as curling or seaweed undulation that occurs during drying of the recording medium.

It is a figure which shows the whole structure of an image recording device. It is a schematic diagram which shows the drying part which concerns on 1st Embodiment. It is a graph which shows the temperature change of the recording medium at the time of drying. It is a schematic diagram which shows the drying part which concerns on 2nd Embodiment. It is a schematic diagram which shows the drying part which concerns on 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each embodiment, components (members and components) having the same function, shape, and the like will be omitted by giving the same reference numerals after being described unless there is a possibility of confusion. . In order to simplify the drawings and the description, even if the components are to be represented in the drawings, the components that do not need to be specifically described in the drawings may be omitted as appropriate.

  FIG. 1 is a diagram showing a schematic configuration of an inkjet printing apparatus 100 according to the first aspect of the present invention. The ink jet printing apparatus 100 is an image recording apparatus that performs printing by ejecting ink onto a transported recording medium 5 (for example, roll paper). The ink jet printing apparatus 100 includes a control unit 1, a transport unit 2, a discharge unit 3, and a drying unit 4.

  The control unit 1 is for controlling each unit of the inkjet printing apparatus 100. As conceptually shown in FIG. 1, the control unit 1 is constituted by a computer having an arithmetic processing unit 11 such as a CPU, a memory 12 such as a RAM, and a storage unit 13 such as a hard disk drive. In addition, an instruction unit 14 such as a keyboard is electrically connected to the control unit 1. The instruction unit 14 is operated by an operator of the apparatus. The operator operates the instruction unit 14 to transport the recording medium 5 by the transport unit 2, discharge ink to the recording medium 5 by the discharge unit 3, and dry the recording medium 5 to which ink has been discharged by the drying unit 4. Instruct. Based on the computer program P and image data D stored in the storage unit 13, the arithmetic processing unit 11 performs arithmetic processing to control the operation of each unit in the inkjet printing apparatus 100 in an integrated manner, and to the recording medium 5. Printing by the inkjet printing apparatus 100 is realized.

  The transport unit 2 is configured to transport the recording medium 5 in the ink jet printing apparatus 100 and includes a winding roller 21, a winding roller 22, and a plurality of auxiliary rollers 23. A motor (not shown) serving as a power source is connected to the unwinding roller 21 and the winding roller 22. The recording medium 5 is fed from the unwinding roller 21 by the power of the motor and wound by the winding roller 22 while being guided by the plurality of auxiliary rollers 23, so that the discharge unit 3 and the drying unit 4 are sequentially rolled to roll. Are continuously conveyed. The auxiliary roller 33 is a driven roller that is not connected to a motor and rotates according to the movement of the recording medium 5, and the number and arrangement are not limited to the example in FIG. Can be increased or decreased. Moreover, you may employ | adopt the drive roller which rotates spontaneously as the auxiliary roller 33 as needed.

  The ejection unit 3 is supplied with ink from an ink supply mechanism such as an ink tank (not shown), ejects ink droplets based on an ink ejection signal generated based on the image data D, and prints on the recording medium 5 (image recording). I do. The ejection unit 3 includes inkjet nozzle groups 30K, 30C, 30M, and 30Y in order from the upstream side in the conveyance direction of the recording medium 5. In the inkjet nozzle groups 30K, 30C, 30M, and 30Y, a plurality of nozzles are arranged in parallel to a direction (width direction of the recording medium 5) orthogonal to the conveyance direction of the recording medium 5 of the recording medium. Since the discharge unit 3 has such a configuration, the discharge unit 3 can perform printing by one discharge without reciprocating scanning in the width direction of the recording medium 5. The discharge unit 3 is a cyan (C), magenta (M), yellow (Y), or black (K) color component that is a color component of a color image from the nozzles of each inkjet nozzle group toward the top surface of the recording medium 5. A color image is recorded on the upper surface of the recording medium 5 by ejecting each ink droplet. In addition, the number of the inkjet nozzle groups 30 of the discharge part 3 is not limited to four, 1-3 may be sufficient and five or more may be sufficient. For example, when performing monochromatic ejection, the number of inkjet nozzle groups may be one, or when ejecting special color inks in addition to K, C, M, and Y colors, the number of inkjet nozzle groups. May be five or more.

The drying unit 4 applies heat to the recording medium 5 having a color image recorded on the upper surface by printing by the ejection unit 3 to evaporate the solvent (mainly water) of the ink. Fix the ink. The drying unit 4 includes a first heating chamber 41 and a second heating chamber 42. Note that the number of heating chambers is not limited to two, and may be any number as long as it is plural (two or more). The drying unit 4 is disposed so as to straddle the recording medium 5 in a direction orthogonal to the conveyance direction with respect to the recording medium 5 conveyed by the conveyance unit 2. The drying unit 4 performs an appropriate drying process on the recording medium 5 based on the drying process signal from the control unit 1. The details of the drying unit 4 will be described later.
<First Embodiment>

  FIG. 2 is a diagram for explaining the drying unit 4 according to the first embodiment of the present invention. In FIG. 2, the recording medium 5 is conveyed from left to right.

  The drying unit 4 includes a first heating chamber 41 and a second heating chamber 42 and is disposed along the conveyance direction of the recording medium 5. Here, what is arranged on the upstream side is the first heating chamber 41, and what is arranged on the downstream side of the first heating chamber 41 is the second heating chamber 42. About the same component in the 1st heating chamber 41 and the 2nd heating chamber 42, description is abbreviate | omitted using the same code | symbol. Therefore, the first heating chamber 41 will be mainly described.

  The first heating chamber 41 includes heating means 400 such as a microwave heater. The first heating chamber 41 has a slit-shaped entrance for the recording medium 5 to enter on the upstream surface in the conveyance direction of the recording medium 5 and a slit-shaped discharge port on the downstream surface. Yes. The recording medium 5 having a color image recorded on the upper surface is conveyed from the entrance to the first heating chamber 41 and discharged from the discharge port.

  A heating unit 400 is disposed inside the first heating chamber 41. Then, by operating based on the drying processing signal from the control unit 1, heat is applied to the recording medium 5 passing through the inside of the first heating chamber 41 to evaporate the ink solvent (mainly water). Such heating means 400 may be an infrared heater or a high-frequency dielectric heater other than the above-described microwave heater.

  A case where a microwave heater is used as the heating unit 400 will be described. The first heating chamber 41 is provided with a microwave introduction port (not shown) in addition to the inlet and outlet of the recording medium 5. And the recording medium 5 can be heated by irradiating the recording medium 5 with the microwave radiated | emitted from the microwave generation part comprised with a magnetron etc. FIG. In the case of using a microwave heater, the first heating chamber 41 has a shield structure and is formed of aluminum, copper, stainless steel or the like in order to prevent leakage of the microwave.

  A major difference between the first heating chamber 41 and the second heating chamber 42 is that the second heating chamber 42 has a heating chamber moving mechanism that allows the second heating chamber 42 to move in a direction along the conveyance direction of the recording medium 5. It is a point provided with 422. The heating chamber moving mechanism 422 includes, for example, a guide rail, a ball screw, a motor, and the like, and moves the second heating chamber 42 in the direction AR1 along the transport direction in accordance with a movement processing signal from the control unit 1. In FIG. 2, the second heating chamber 42 of the second drying unit 42 before movement is indicated by a broken line, and the second heating chamber 42 after movement is indicated by a solid line.

  When the second heating chamber 42 moves in the direction AR1 along the conveyance direction of the recording medium 5 with respect to the first heating chamber 41, the conveyance distance between the respective drying units is changed. In other words, the transfer time from the first heating chamber 41 to the second heating chamber 42 is changed, and the cooling time of the recording medium 5 heated by heating in the first heating chamber 41 can be changed. .

  The effect by this embodiment is demonstrated referring FIG. FIG. 3A is a graph showing the temperature change of the recording medium 5 when the distance between the respective heating chambers is constant, and FIG. 3B shows that the recording medium 5 has a desired temperature change. FIG. 6 is a graph showing a temperature change when the transfer distance between the first heating chamber 41 and the second heating chamber 42 is determined.

  FIG. 3A shows that when the transport distance between the heating chambers is fixed, the cooling time Ta of the heated recording medium 5 is always constant. When the cooling time Ta is not sufficient for the time required for cooling the recording medium 5 between the heating chambers, the temperature of the recording medium 5 rises as shown by the white arrow in FIG. This causes evaporation of moisture contained in the non-printing portion of the recording medium 5, for example, in the case of paper, deformation such as curling or seaweed-like undulation occurs, resulting in poor conveyance or defective printing in the subsequent process, or cutting / binding. It becomes a factor which produces the defect in a process.

  On the other hand, in FIG. 3B, the second heating chamber 42 is moved by the heating chamber moving mechanism 422 based on at least one condition among the type of recording medium 5, the conveyance speed, the density of ink image, the type of ink, and the like. The conveyance distance between the first heating chamber 41 and the second heating chamber 42 is determined. As a result, the desired cooling time Tb can be sufficiently provided for the heated recording medium 5, and the temperature of the recording medium 5 can be kept constant as shown by the white arrow in FIG. It becomes possible.

  As in the invention described in this embodiment, the conveyance distance between the first heating chamber 41 and the second heating chamber 42 can be arbitrarily set, so that the type of the recording medium 5, the conveyance speed, the density of the ink image, and Since an optimal cooling time can be set according to the type of ink, for example, even when the recording medium 5 is paper, deformation such as curl or seaweed undulation is suppressed, and conveyance failure or post-process It is possible to prevent defects in printing or defects in the cutting / binding process.

In the present embodiment, the second heating chamber 42 is moved with respect to the first heating chamber 41. However, the present invention is not limited to this. In order to obtain the same function and effect, it is sufficient that the relative distance between the first heating chamber 41 and the second heating chamber 42 can be changed. Therefore, the first heating chamber 41 may be moved, or both the first heating chamber 41 and the second heating chamber 42 may be moved.
<Second Embodiment>

  FIG. 4 is a diagram for explaining a drying unit 4A according to the second embodiment of the present invention. In the following, the same or substantially the same configuration as the configuration of the drying unit 4 of the first embodiment is denoted by the same reference numeral, and detailed description thereof is omitted.

  In the drying unit 4 </ b> A, two fixed rollers 410 and 410 are arranged on the conveyance path of the recording medium 5 between the first heating chamber 41 and the second heating chamber 42 at a distance. Further, a movable roller 420 is provided in the conveyance path of the recording medium 5 between the fixed rollers 410 and 410 and is movable in a direction orthogonal to the conveyance direction of the recording medium 5. Note that the number and arrangement of the fixed roller 410 and the movable roller 420 are not limited to the example of FIG. 4 and can be increased or decreased as necessary.

  The fixed rollers 410 and 410 are disposed so as to contact the one main surface 5A that is the printing surface side of the recording medium 5, and the movable roller 420 is the other main surface that is the surface opposite to the printing surface of the recording medium 5. It arrange | positions so that 5B may be contact | abutted.

  The movable roller 420 includes an elevating mechanism (not shown). The movable roller 420 moves up and down in the AR2 direction based on the movement processing signal from the control unit 1.

  As shown in FIG. 4, the vertical position of the movable roller 420 is made higher than the positions of the fixed rollers 410 and 410, so that the recording medium 5 between the first heating chamber 41 and the second heating chamber 42 is placed. The transfer distance can be changed without changing the distance between the first heating chamber 41 and the second heating chamber 42.

Thereby, the effect similar to 1st Embodiment can be acquired. In this embodiment, the fixed rollers 410 and 410 are disposed so as to contact the one main surface 5A of the recording medium 5, and the movable roller 420 is disposed so as to contact the other main surface 5B of the recording medium 5. The fixed rollers 410 and 410 may be in contact with the other main surface 5B of the recording medium 5, and the movable roller 420 may be disposed in contact with the one main surface 5A of the recording medium 5. In this case, the elevating mechanism moves the movable roller 420 below the conveyance path of the recording medium 5.
<Third Embodiment>

  FIG. 5 is a diagram for explaining a drying section 4B according to the third embodiment of the present invention. The third embodiment has a configuration in which the drying units of the first embodiment and the second embodiment described above are combined. Therefore, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The third embodiment is different from the first and second embodiments in the arrangement of the second heating chamber 42 described in the first embodiment in the conveyance direction of the recording medium 5 and in the second embodiment. The two fixed rollers 410 and the movable roller 420 are arranged.

  As shown in FIG. 5, the drying unit 4 </ b> B has a first heating chamber 41, a second heating chamber 42, two fixed rollers 410 and a movable roller 420, and a third heating chamber from the upstream side with respect to the conveyance direction of the recording medium 5. 43 are arranged in this order. Here, the third heating chamber 43 has the same configuration as that of the first heating chamber 41, and thus the description thereof is omitted. The reason for arranging in this order will be described below.

  In general, an inkjet ink contains a glycol-based solvent such as glycerin in addition to moisture. While the boiling point of water is about 100 ° C., the boiling point of solvents such as glycols is about 140 to 200 ° C., which is higher than water. Accordingly, when drying is performed with a drying energy of about 100 ° C., the moisture of the ink is evaporated and dried, but the solvent remains without being evaporated. That is, the drying is insufficient. Complete drying of these solvents requires more drying energy than drying the water.

  When such an ink-jet ink is used, the moisture contained in the ink-jet ink can be evaporated by changing the transport distance of the recording medium 5 between the first heating chamber 41 and the second heating chamber 42. This is because the drying energy of about 100 ° C. may be used to evaporate the moisture of the ink-jet ink, and therefore the cooling time of the recording medium 5 may be relatively short. Therefore, the first heating chamber 41 and the first heating chamber 41 are disposed before the drying unit 4B. It is preferable to provide two heating chambers 42.

  In addition, it is preferable that two fixed rollers 410 and a movable roller 420 are disposed between the second heating chamber 42 and the third heating chamber 43 on the downstream side in the transport direction of the second heating chamber 42. This is because the conveyance distance of the recording medium 5 can be set freely depending on the number and arrangement of the fixed roller 410 and the movable roller 420, and even when heated to a high temperature to evaporate the solvent contained in the ink-jet ink, sufficient cooling is possible. This is because time can be secured.

  As described above, by providing the drying unit 4B described in the third embodiment, even when an ink-jet ink containing a high-boiling solvent is used, deformation such as curl or seaweed-like undulation is suppressed. Inkjet ink can be dried efficiently.

  While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention.

  For example, in the above-described embodiment, each heating chamber has been described as a configuration having only the heating means 400. However, the present invention is not limited to this, and may be configured to further include a blowing means arranged outside the heating chamber. . By sending air into the heating chamber by the air blowing means, the ink can be evaporated and dried, and the drying efficiency of the recording medium 5 can be improved.

  In the above embodiment, the first heating chamber 41 and the second heating chamber are arranged in order along the conveyance direction of the recording medium 5, but between the first heating chamber 41 and the second heating chamber 42, Furthermore, the structure provided with a cooling unit may be sufficient. By providing a cooling unit between the first heating chamber 41 and the second heating chamber 42, the recording medium 5 can be efficiently cooled. As such a cooling unit, a mechanism for blowing cool air or the like can be employed.

  In the above-described embodiment, the ink jet method has been described as an example using the image recording unit as the ejection unit 3. However, the image recording unit in the present invention may be a method other than inkjet (for example, offset printing, gravure printing, etc.) as long as image recording is performed on a long recording medium.

  In the above embodiment, the recording medium 5 has been described mainly using paper as an example. However, the recording medium in the present invention can also be applied to long substrates other than paper (for example, resin films, metal foils, glass, etc.).

  Moreover, you may combine suitably each element described in said embodiment and modification in the range which does not produce inconsistency.

DESCRIPTION OF SYMBOLS 1 Control part 2 Conveyance part 3 Ejection part (image recording part)
4 Drying unit 5 Recording medium 11 Instruction unit 12 Memory 13 Operation processing unit 14 Storage unit 21 Unwinding roller 22 Winding roller 30 Inkjet nozzle group 41 First heating chamber 42 Second heating chamber 100 Inkjet printing apparatus (image recording apparatus)
410 fixed roller 420 movable roller (conveyance distance changing means)
422 Heating chamber moving mechanism (conveyance distance changing means)

Claims (5)

A transport unit for continuously transporting a long recording medium;
An image recording unit that records an ink image based on image data on the recording medium conveyed by the conveyance unit;
A drying unit having a plurality of heating chambers for heating and drying the ink image recorded on the recording medium by the image recording unit;
A transport distance changing means for changing a transport distance of the recording medium between the heating chambers between the plurality of heating chambers;
An image recording apparatus comprising: The image recording apparatus according to claim 1,
The transport distance changing means is
A heating chamber moving mechanism for moving the heating chamber in a direction along a conveyance direction of the recording medium;
An image recording apparatus. The image recording apparatus according to claim 1 or 2, wherein
The transport distance changing means is
At least two or more fixed rollers disposed in the conveyance path between the plurality of heating chambers, and abutting against one main surface of the recording medium;
A movable roller disposed in the transport path between the fixed rollers and movable in a direction perpendicular to the transport direction of the recording medium, contacting the other main surface of the recording medium. Image recording device. The image recording apparatus according to any one of claims 1 to 3, wherein
The transport distance changing unit determines a transport distance between the plurality of heating chambers according to at least one of the type of the recording medium, the transport speed, the density of the ink image, and the type of ink. Recording device. The image recording apparatus according to any one of claims 1 to 4, wherein:
The image recording apparatus, wherein the heating chamber has a microwave heater for heating and drying an ink image recorded on the recording medium.