JP2022124730A - Dryer, printing system, and drying method - Google Patents

Abstract

To stably transport a printing medium in a section from a front stage rotor between upper and middle stage transport parts to a rear stage rotor after a lower stage transport part, upon drying the printing medium while transporting the printing medium so as to pass through the upper, middle and lower stage transport parts in order.SOLUTION: A printing medium M to be transported between a roller 522 (front stage rotator) and a roller 561 (rear stage rotator) is supported by a roller 74 (intermediate rotor) of a lower stage transport unit 51l rotating while contacting a back surface M2 (non-printing surface) of a printing medium M. Therefore, the printing medium M can be stably transported in a section from the roller 522 between an upper stage transport part 51u and a middle stage transport part 51m to the roller 561 after the lower stage transport part 51l.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technique for drying a print medium with ink adhered thereon with hot air.

Japanese Unexamined Patent Application Publication No. 2002-100002 discloses a drying device that dries a print medium by ejecting gas from nozzles onto the print medium to which ink has adhered. In particular, in this drying device, the three-stage conveying units are arranged in the vertical direction, and each conveying unit conveys the print medium in the horizontal direction so that the print medium is conveyed in the order of the upper conveying unit, the middle conveying unit, and the lower conveying unit. passes through. Specifically, the upper conveying section conveys the print medium to one side, the middle conveying section positioned below the upper conveying section conveys the print medium to the other side, and the lower conveying section positioned below the middle conveying section conveys the print medium to the other side. The transport unit transports the print medium to one side. Each transport section has a plurality of nozzles arranged along the print medium above and below the print medium, and jets gas from these nozzles. As a result, the print medium can be dried while being transported without contacting the print medium.

Two rollers are vertically arranged between the upper transport section and the middle transport section, and the print medium transported to one side from the upper transport section is folded downward by the upper roller and The sheet is folded back to the other side by the rollers of , and advances to the intermediate conveying section. Two air turn bars are arranged vertically between the middle and lower transport sections, and the print medium conveyed from the middle and lower transport sections to the other side is folded downward by the upper air turn bar and then folded back to the lower side. is turned back to one side by the air turn bar and proceeds to the lower conveying section. Further, a roller is arranged in the rear stage of the lower conveying section (in other words, the downstream side in the conveying direction of the print medium), and the print medium conveyed to one side from the lower conveying section is supported by the roller.

JP 2020-148383 A

In such a drying apparatus, the print medium floats between the front rotating body (roller) provided between the upper transport section and the middle transport section and the rear rotating body (roller) provided behind the lower transport section. Since it is transported by transportation, there is no member that contacts the print medium. For this reason, the print medium is not conveyed straight in this section, and the print medium may be biased in the width direction or drop out of the nozzles.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems. It is an object of the present invention to stably convey a print medium in a section from a lower-stage conveying section to a rear-stage rotating body after the lower-stage conveying section.

A drying apparatus according to the present invention has a plurality of upper printing surface nozzles arranged above a long band-shaped printing medium having a printing surface to which ink is adhered and a non-printing surface opposite to the printing surface. An upper transport section that transports the print medium to one side in the horizontal direction with the surface facing upward and ejects gas from the upper print surface nozzles onto the print surface, and a front stage that rotates while contacting the non-print surface of the print medium. a front-stage folding section having a rotating body, wherein the front-stage rotating body folds the print medium conveyed from the upper-stage conveying section to the other side opposite to the one side; and a plurality of middle-stage printing surfaces arranged on the lower side of the print medium. A middle-stage transport in which a print medium having nozzles and folded back to the other side by a front-stage folding section is transported to the other side with the print surface facing downward while jetting gas from the middle-stage print surface nozzles onto the print surface. and a non-contact support member that supports the print medium by injecting gas onto the printing surface of the print medium, and the print medium conveyed from the intermediate conveying unit is folded back downward by the non-contact support member. It has a post-stage folding section that folds back to one side and a plurality of lower-stage print surface nozzles arranged above the print medium, and the print medium folded back to one side by the post-stage folding section is held with the print surface facing upward. a lower conveying section for ejecting gas onto the printing surface from the lower printing surface nozzles while conveying to one side; and at least one of the lower transport section has an intermediate rotator that rotates while being in contact with the non-printing surface of the print medium that is transported between the front rotator and the rear rotator.

In the drying method according to the present invention, a long band-shaped print medium having a print surface to which ink is adhered and a non-print surface on the opposite side of the print surface has a plurality of upper print surface nozzles arranged on the upper side of the print medium. while conveying the print medium to one side in the horizontal direction with the print surface facing upward, and rotating the print medium conveyed to the one side while contacting the non-print surface of the print medium a step of folding back the printing medium on the opposite side to the other side by means of the preceding rotating body; a step of ejecting gas onto the printing surface from a plurality of middle-stage printing surface nozzles arranged in a row; a step of folding the print medium downward by the contact support member and then folding the print medium to one side; a step of ejecting gas from a plurality of lower printing surface nozzles onto the printing surface; The intermediate rotor that rotates while contacting the non-printing surface supports the print medium conveyed between the front-stage rotor and the rear-stage rotor.

In the present invention (drying apparatus and drying method) configured as described above, the print medium is transported between the front-stage rotator and the rear-stage rotator by the intermediate rotator that rotates while being in contact with the non-printing surface of the print medium. is supported. Therefore, it is possible to stably convey the print medium in the section from the front rotating member between the upper and middle conveying units to the rear rotating member after the lower conveying unit.

In addition, the intermediate rotator constitutes the drying device so as to face the interval between the two adjacent lower printing surface nozzles in the lower conveying unit from below with the printing medium interposed therebetween and contact the non-printing surface. may With such a configuration, the print medium transported by the lower transport section can be supported by the intermediate rotator, and the print medium can be stably transported toward the rear rotator behind the lower transport section.

Further, the drying device may be configured such that an intermediate rotating body is provided for each of the plurality of intervals formed in the array of the plurality of lower printing surface nozzles. In such a configuration, a plurality of lower printing surface nozzles and a plurality of intermediate rotating bodies are arranged so that one lower printing surface nozzle and one intermediate rotating body are alternately arranged (that is, arranged in a zigzag pattern). Therefore, the print medium transported by the lower transport section can be firmly supported by the plurality of intermediate rotors, and the print medium can be very stably transported toward the rear rotor after the lower transport section.

Further, a position sensor for detecting a position in the width direction of the print medium and a rotator driving section for driving the latter rotator are provided, and the rotator driving section detects the position of the latter rotator according to the position of the print medium detected by the position sensor. The drying device may be configured to adjust the position of the print medium in the width direction by displacing the . In such a configuration, the position of the print medium in the width direction is adjusted by displacing the post-rotating body according to the result of detecting the position in the width direction of the print medium, thereby stabilizing the transport of the print medium. However, if the transport of the print medium to the rear rotor is too unstable, the transport of the print medium cannot be sufficiently stabilized by the displacement of the rear rotor. On the other hand, since the print medium is supported by the intermediate rotator, the print medium is stably conveyed to the rear rotator. As a result, it is possible to sufficiently stabilize the transport of the print medium by the displacement of the post-stage rotating body.

Further, the middle conveying unit has a plurality of middle non-printing surface nozzles arranged above the print medium, and the middle non-printing surface nozzles and the middle non-printing surface nozzles are arranged in a zigzag pattern. The drying device may be configured such that the nozzles eject gas onto the non-printing surface, and the intermediate rotating body is not provided for the print medium transported by the intermediate transport unit. With this configuration, the print medium before reaching the lower transport section can be thoroughly dried by the gas ejected from both the middle print surface nozzles and the middle non-print surface nozzles of the middle transport section. Therefore, both reliable drying and stable transport of the print medium can be achieved.

In addition, a drying furnace that accommodates the upper conveying section, the middle conveying section, and the lower conveying section, and an exhaust section that discharges gas from the drying furnace are further provided. The drying device may be configured such that an amount of gas corresponding to the amount of gas ejected from the printing surface nozzles and the lower printing surface nozzles is exhausted from the drying furnace. In such a configuration, an airflow passing through the drying furnace can be generated by jetting the gas from the nozzle and exhausting the gas from the exhaust section. However, if the number of nozzles is small, it may not be possible to ensure sufficient airflow. On the other hand, by providing a plurality of middle-stage non-printing surface nozzles in the middle-stage conveying section, it is possible to sufficiently secure an air flow passing through the drying oven and dry the print medium firmly. Therefore, both reliable drying and stable transport of the print medium can be achieved.

A printing system according to the present invention includes a printing device that prints an image by ejecting ink onto a printing surface of a printing medium, and the drying device that dries the ink ejected by the printing device and adhered to the printing surface. . Therefore, in order to dry the print medium while conveying the print medium so as to pass through the upper, middle, and lower conveying sections in order, the front rotating body between the upper and middle conveying sections to the rear rotating body after the lower conveying section It is possible to stably convey the print medium in the section of .

As described above, according to the present invention, in order to dry the print medium while conveying the print medium so as to pass through the upper, middle, and lower conveying sections in order, it is possible to dry the print medium from the front rotating body to the lower conveying section between the upper, middle, and lower conveying sections. It is possible to stably convey the print medium in the section from the conveying section to the post-stage rotating body.

1 is a front view schematically showing an example of a printing system according to the present invention; FIG. FIG. 2 is a front view schematically showing a drying device included in the printing system of FIG. 1; The schematic diagram which expands and shows each ventilation dryer of an upper-stage conveyance part and a lower-stage conveyance part partially. The schematic diagram which expands partially and shows the ventilation dryer of a middle-stage conveyance part. FIG. 4 is a side view schematically showing the configuration of the position adjusting section; FIG. 2 is a plan view schematically showing the configuration of a position adjusting section; FIG. 2 is a block diagram showing the electrical configuration of the drying device; FIG. 2 is a block diagram showing a configuration for controlling injection quantity and exhaust quantity;

FIG. 1 is a front view schematically showing an example of a printing system according to the invention. A horizontal direction X, a horizontal direction Y perpendicular to the horizontal direction X, and a vertical direction Z are indicated as appropriate in FIG. 1 and the following figures. As shown in FIG. 1, the printing system 1 has a configuration in which a coating device 2, a printing device 3, and a drying device 5 are arranged in this order in the horizontal direction X (arrangement direction). This printing system 1 transports a long belt-shaped print medium M from a delivery roll 11 to a take-up roll 12 by roll-to-roll, and applies a coating liquid to the print medium M coated with a coating liquid by a coating device 2. 3 prints an image by an inkjet method, and a drying device 5 dries the printing medium M on which the image is printed. The material of the print medium M is a film such as OPP (oriented polypropylene) or PET (polyethylene terephthalate). However, the material of the print medium M is not limited to film, and may be paper or the like. Such a print medium M has flexibility. Further, hereinafter, of the two surfaces of the printing medium M, the surface on which an image is printed is referred to as a surface M1, and the surface opposite to the surface M1 is referred to as a back surface M2.

The coating device 2 includes a pan 21 that stores a liquid primer (coating liquid), a gravure roller 22 that is partially immersed in the primer stored in the pan 21, and a transport section 23 that transports the print medium M. In the coating device 2, a coating area is provided in which the gravure roller 22 contacts the print medium M transported by the transport unit 23 from below. The print medium M is conveyed along the . On the other hand, the gravure roller 22 supplies the primer to the application area by rotating while holding the primer on its peripheral surface. Thus, the primer supplied by the gravure roller 22 is applied to the surface M1 of the print medium M in the application area. Further, in the application area, the traveling direction of the print medium M is opposite to the rotating direction of the peripheral surface of the gravure roller 22 . That is, the primer is applied to the print medium M by a so-called reverse kiss method. Then, the conveying unit 23 conveys the printing medium M from the coating device 2 to the printing device 3 while directing the surface M1 of the printing medium M coated with the primer upward.

The printing device 3 includes a housing 31, a color printing unit 32 arranged in the housing 31, a white printing unit 33 arranged above the color printing unit 32 in the housing 31, and A transport unit 34 transports the print medium M by a plurality of rollers arranged.

The color printing unit 32 has a plurality (six) of ejection heads 321 arranged in the traveling direction of the printing medium M above the printing medium M conveyed by the conveying unit 34 . The plurality of ejection heads 321 has nozzles facing from above the surface M1 of the printing medium M passing below each, and ejects color inks of different colors from the nozzles by an inkjet method. Here, color ink means ink other than white, and includes ink such as cyan, magenta, yellow, and black. In this way, the plurality of ejection heads 321 of the color printing unit 32 eject color ink from above onto the surface M1 of the print medium M passing below them, thereby printing a color image on the surface M1 of the print medium M.

Also, the white printing section 33 has a single ejection head 331 arranged above the print medium M conveyed by the conveying section 34 . The ejection head 331 has nozzles facing from above the surface M1 of the print medium M passing therebelow, and ejects white ink from the nozzles by an inkjet method. In this way, the ejection head 331 of the white printing unit 33 prints a white image on the surface M1 of the printing medium M by ejecting white ink from above onto the surface M1 of the printing medium M passing below.

The printing medium M is carried from the coating device 2 into the housing 31 of the printing device 3 with the surface M1 facing upward. On the other hand, the transport unit 34 performs two upside-down rotations on the print medium M carried into the housing 31 , and then transports the print medium M to the color printing unit 32 . As a result, each ejection head 321 of the color printing unit 32 can eject color ink onto the surface M1 of the print medium M facing upward. Further, the transport unit 34 performs two upside-down rotations of the printing medium M to which the color ink is attached, and then transports the printing medium M to the white printing unit 33 . As a result, the ejection head 331 of the white printing unit 33 can eject white ink onto the surface M1 of the print medium M facing upward. In this way, the print medium M with the color ink and the white ink adhered to the surface M1 is transported from the printing device 3 to the drying device 5 by the transport section 34 .

FIG. 2 is a front view schematically showing a drying device included in the printing system of FIG. 1. FIG. In the figure, one side X1 and the other side X2 in the horizontal direction X are shown, and the one side X1 and the other side X2 are opposite to each other. The drying device 5 dries the print medium M while properly folding the print medium M in the horizontal direction X and conveying it. The drying device 5 includes a housing 6 (drying oven) arranged on one side X1 of the housing 31 of the printing device 3 . The housing 6 has a rectangular parallelepiped shape extending in the horizontal direction X, and both side walls 6a and 6b of the housing 6 in the horizontal direction X are parallel to the vertical direction Z and perpendicular to the horizontal direction X. , are spaced apart in the horizontal direction X and face each other.

Of the side walls 6a and 6b, the side wall 6a on the other side X2 in the horizontal direction X (the side of the printing device 3) has a carry-in port 61 penetrating in the horizontal direction X, and the side wall 6a on the side X1 in the horizontal direction X (the side of the printing device 3). ), an outlet 66 penetrates in the horizontal direction X through the housing 6b. Then, the print medium M carried out from the printing device 3 is carried into the housing 6 through the carry-in port 61 and then carried out of the housing 6 through the carry-out port 66 .

That is, the drying device 5 includes a transport section 51 for transporting the print medium M inside the housing 6 , and the transport section 51 transports the print medium M from the carry-in port 61 to the carry-out port 66 . The transport unit 51 includes an upper transport unit 51u that transports the print medium M from the other side X2 to the one side X1, a middle transport unit 51m that transports the print medium M from the one side X1 to the other side X2, and a lower conveying section 51l that conveys the printing medium M from the other side X2 toward the one side X1. The middle conveying section 51m is arranged below the upper conveying section 51u, and the lower conveying section 51l is arranged below the middle conveying section 51m. Therefore, the print medium M transported by the upper transport unit 51u, the print medium M transported by the middle transport unit 51m, and the print medium M transported by the lower transport unit 51l are aligned in the vertical direction Z, in other words, When viewed in the vertical direction Z, they overlap each other. Specifically, the upper transport unit 51u transports the print medium M at the same height as the entrance 61, and the print medium M is transported to the upper stage with the front surface M1 facing upward and the back surface M2 facing downward. It is conveyed in the horizontal direction X by the portion 51u. The middle conveying unit 51m conveys the print medium M below the upper conveying unit 51u, and the print medium M is transported in the horizontal direction X by the middle conveying unit 51m with the front surface M1 facing downward and the back surface M2 facing upward. transported to The lower transport unit 51l transports the print medium M below the middle transport unit 51m, and the print medium M is transported horizontally by the lower transport unit 51l in a state in which the front surface M1 faces upward and the back surface M2 faces downward. transported to

The transport section 51 also has a front folding section 52 that folds the print medium M from the upper transport section 51u to the middle transport section 51m. The front folding part 52 has two rollers 521 and 522 arranged in the vertical direction Z on one side X1 of the housing 6 . Each of the rollers 521 and 522 is arranged parallel to the horizontal direction Y and supported by the housing 6 around a rotation axis parallel to the horizontal direction Y. As shown in FIG. Of the rollers 521 and 522, the upper roller 521 wraps around the back surface M2 of the print medium M conveyed to the one side X1 by the upper conveying unit 51u, folds the print medium M downward, and rotates the lower roller 521. 522 winds the back surface M2 of the print medium M folded back by the roller 521 to fold the print medium M to the other side.

In this way, the printing medium M is folded back from the one side X1 to the other side X2 by the front folding section 52, so that the front surface M1 and the rear surface M2 of the printing medium M are turned upside down. The print medium M folded back to the other side X2 by the front folding section 52 is transported to the other side X2 by the intermediate transport section 51m.

Further, the transport section 51 has a rear folding section 54 that folds the print medium M from the middle transport section 51m to the lower transport section 51l. The rear folded portion 54 has two air turn bars 541 and 542 arranged in the vertical direction Z on the other side X2 of the housing 6 . Each of the air turn bars 541 and 542 is arranged parallel to the horizontal direction Y and supported by the housing 6 . Of the air turn bars 541 and 542, the upper air turn bar 541 injects air onto the surface M1 of the print medium M conveyed from the intermediate conveying section 51m toward the other side X2. As a result, the air turn bar 541 folds the print medium M downward while leaving a gap between it and the surface M1 of the print medium M. As shown in FIG. Among the air turn bars 541 and 542, the lower air turn bar 542 jets air onto the surface M1 of the printing medium M conveyed downward from the air turn bar 541. As shown in FIG. As a result, the air turn bar 542 folds the print medium M to the one side X1 while leaving a gap between it and the front surface M1 of the print medium M. As shown in FIG.

In this way, the printing medium M is folded back from the other side X2 to the one side X1 by the rear folding section 54, so that the front surface M1 and the rear surface M2 of the printing medium M are turned upside down. The print medium M folded back to the one side X1 by the rear folding section 54 is transported to the one side X1 by the lower transport section 51l.

The transport section 51 also has a roller 561 that supports the print medium M transported from the lower transport section 51l to the one side X1. The roller 561 is arranged parallel to the horizontal direction Y on one side X1 of the housing 6 and supported by the housing 6 so as to be rotatable about a rotation axis parallel to the horizontal direction Y. As shown in FIG. Then, the roller 561 supports the print medium M by rotating while contacting the back surface M2 of the print medium M transported from the lower transport unit 51l to the one side X1. Note that the roller 561 constitutes a part of the position adjustment mechanism 56 that adjusts the position of the print medium M in the horizontal direction Y, as will be described later.

The drying apparatus 5 includes six fan dryers 7a to 7f in the housing 6. As shown in FIG. Among these, two blow dryers 7 a and 7 b are provided in the upper conveying section 51 u and arranged between the inlet 61 and the rollers 521 . The blower dryers 7 a and 7 b dry the print medium M conveyed from the inlet 61 toward the rollers 521 . The two blow dryers 7 c and 7 d are provided in the intermediate conveying section 51 m and arranged between the roller 522 and the air turn bar 541 . The blower dryers 7 c and 7 d dry the print medium M conveyed from the roller 522 toward the air turn bar 541 . The two blow dryers 7 e and 7 f are provided in the lower conveying section 51 l and arranged between the air turn bar 542 and the rollers 561 . The blower dryers 7 e and 7 f dry the print medium M conveyed from the air turn bar 542 toward the rollers 561 .

FIG. 3 is a partially enlarged schematic diagram showing the blower dryers of the upper and lower conveying sections, and FIG. 4 is a partially enlarged schematic diagram showing the blower dryers of the middle conveying section. . Next, the blower dryers 7a to 7f will be described with reference to FIGS. 3 and 4. FIG.

The blower dryer 7 a has a blower unit 71 u arranged above the print medium M conveyed from the inlet 61 toward the rollers 521 . The blower unit 71u has a blower chamber 72u extending in the horizontal direction X above the print medium M. As shown in FIG. Both end faces of the blowing chamber 72u in the horizontal direction X are planes perpendicular to the horizontal direction X and parallel to the vertical direction Z. As shown in FIG. The air blowing chamber 72u is supplied with hot air (air of 60 degrees or higher) generated by heating air with a heater provided outside the printing system 1 . The lower surface of the blowing chamber 72u is a nozzle arrangement plane 73u that faces the surface M1 (upper surface) of the print medium M facing upward from above. This nozzle arrangement plane 73u is a plane parallel to the horizontal direction X and perpendicular to the vertical direction Z. As shown in FIG. Furthermore, the blower unit 71u has a plurality of nozzles 76u arranged at a predetermined pitch in the horizontal direction X on the nozzle arrangement plane 73u. In this way, the plurality of nozzles 76u are arranged between the nozzle arrangement plane 73u and the surface M1 of the print medium M, and face the surface M1 of the print medium M. As shown in FIG. Each nozzle 76u communicates with a blowing chamber 72u, and the hot air supplied to the blowing chamber 72u is jetted from the nozzles 76u onto the surface M1 of the print medium M to dry the print medium M. In this manner, among the plurality of air dryers 7a to 7f, the air dryer 7a dries the print medium M carried into the housing 6 first.

Further, the blower dryer 7a has a plurality of rollers 74 (the same number as the nozzles 76u) arranged below the print medium M conveyed from the inlet 61 toward the rollers 521 . A plurality of rollers 74 are arranged at a predetermined pitch in the traveling direction (horizontal direction X) of the print medium M, and the peripheral surface of each roller 74 contacts the back surface M2 (lower surface) of the print medium M from below. Each roller 74 rotates following the print medium M about a rotation axis parallel to the horizontal direction Y, and supports the print medium M from below. In addition, the roller 74 is spirally provided with fine grooves, so that air can easily escape from between the print medium M and the peripheral surface of the roller 74 .

Incidentally, the nozzle 76u faces the range between the two rollers 74 that are adjacent in the horizontal direction X from above, and the roller 74 is located downward in the range between the upper two nozzles 76u that are adjacent in the horizontal direction X. Face from the side. That is, in the horizontal direction X, the nozzles 76u and the rollers 74 are alternately arranged at a pitch that is half the predetermined pitch, and are alternately arranged one by one in the horizontal direction X in a plan view from the vertical direction Z. In other words, the nozzles 76u and the rollers 74 are arranged in a zigzag pattern.

In such a configuration, as shown in FIG. 3, the print medium M is pushed downward by the hot air from the nozzles 76u at the portion facing the nozzles 76u, and is biased downward from the upper end of the roller 74 to face the roller 74. It is supported by this roller 74 in the portion where it does. Therefore, the print medium M is conveyed in the horizontal direction X from the other side X2 toward the one side X1 while undulating between the upper end of the roller 74 and the area below the upper end.

The blower dryer 7 b is arranged downstream of the blower dryer 7 a in the traveling direction of the print medium M transported from the inlet 61 toward the rollers 521 . Similar to the blow dryer 7a, the blow dryer 7b includes a blow unit 71u arranged above the print medium M conveyed from the inlet 61 toward the rollers 521, and a plurality of air blow dryers 71u arranged below. and rollers 74 of . In the blow dryer 7b, a plurality of rollers 74 support the back surface M2 of the print medium M from below, and a plurality of nozzles 76u (the same number as the rollers 74) of the blower unit 71u blow hot air onto the front surface M1 of the print medium M from above. is jetted, and the print medium M is dried.

The blower dryer 7c has blower units 71u and 71l arranged above and below the print medium M transported from the roller 522 toward the air turn bar 541, respectively. The upper blower unit 71u has a blower chamber 72u extending in the horizontal direction X above the print medium M. As shown in FIG. Both end faces of the blowing chamber 72u in the horizontal direction X are planes perpendicular to the horizontal direction X and parallel to the vertical direction Z. As shown in FIG. The above hot air is supplied to the air blowing chamber 72u. The lower surface of the blowing chamber 72u is a nozzle arrangement plane 73u that faces the rear surface M2 (upper surface) of the printing medium M facing upward from above. This nozzle arrangement plane 73u is a plane parallel to the horizontal direction X and perpendicular to the vertical direction Z. As shown in FIG. Furthermore, the blower unit 71u has a plurality of nozzles 76u arranged at a predetermined pitch in the horizontal direction X on the nozzle arrangement plane 73u. Thus, the plurality of nozzles 76u are arranged between the nozzle arrangement plane 73u and the back surface M2 of the print medium M and face the back surface M2 of the print medium M. Each nozzle 76u communicates with the blowing chamber 72u, and the hot air supplied to the blowing chamber 72u is jetted onto the back surface M2 of the print medium M from the nozzles 76u.

The lower blower unit 71l has a blower chamber 72l extending in the horizontal direction X below the print medium M. As shown in FIG. Both end surfaces of the blowing chamber 72l in the horizontal direction X are planes perpendicular to the horizontal direction X and perpendicular to the vertical direction Z. As shown in FIG. The hot air described above is supplied to the blowing chamber 72l. The upper surface of the blowing chamber 72l is a nozzle arrangement plane 73l that faces the surface M1 (lower surface) of the print medium M facing downward from below. This nozzle arrangement plane 73l is a plane parallel to the horizontal direction X and perpendicular to the vertical direction Z. As shown in FIG. Furthermore, the blower unit 71l has a plurality of nozzles 76l arranged at a predetermined pitch in the horizontal direction X on the nozzle arrangement plane 73l. In this way, the plurality of nozzles 76l are aligned between the nozzle arrangement plane 73l and the surface M1 of the print medium M and face the surface M1 of the print medium M. Each nozzle 76l communicates with a blowing chamber 72l, and the hot air supplied to the blowing chamber 72l is jetted onto the surface M1 of the print medium M from the nozzles 76l.

Thus, the print medium M is sandwiched between the blower unit 71u and the blower unit 71l. In other words, the print medium M conveyed by the middle conveying section 51m passes between the blower unit 71u and the blower unit 71l. In this manner, the blower dryer 7c dries the print medium M transported by the intermediate transport unit 51m by jetting hot air from the upper and lower blower units 71u and 71l.

Incidentally, the upper nozzle 76u faces the range between the two lower nozzles 76l adjacent in the horizontal direction X from above, and the lower nozzle 76l is located between the two upper nozzles 76l adjacent in the horizontal direction X. It faces the range between the nozzles 76u from below. In other words, in the horizontal direction X, the upper nozzles 76u and the lower nozzles 76l are alternately arranged at a pitch that is half the predetermined pitch. line up. In other words, the nozzles 76u and 76l are arranged in a zigzag pattern. Such a staggered arrangement of the nozzles 76u and 76l is realized by shifting the positions of the blowing chambers 72u and 72l in the horizontal direction X with respect to each other.

In such a configuration, as shown in FIG. 4, the print medium M is pushed downward by the hot air from the nozzles 76u at the portion facing the upper nozzles 76u, and is biased downward from the transport center line L. A portion facing the nozzle 76l is pushed upward by the hot air from the nozzle 76l, and is biased upward from the conveying center line L. As shown in FIG. Here, the transport center line L is a horizontal imaginary straight line having equal distances in the vertical direction Z from the nozzles 76u and 76l. Therefore, the print medium M is conveyed in the horizontal direction X from one side X1 to the other side X2 while waving between the upper side and the lower side of the conveyance center line L.

The blow dryer 7 d is arranged downstream of the blow dryer 7 c in the traveling direction of the print medium M transported from the roller 522 toward the air turn bar 541 . The blower dryer 7d has blower units 71u and 71l sandwiching the print medium M in the vertical direction Z, like the blower dryer 7c. In the blow dryer 7d, the blower unit 71u blows hot air onto the back surface M2 of the print medium M from above, and the blow unit 71l blows hot air onto the surface M1 of the print medium M from below, thereby drying the print medium M. be done.

Like the blow dryer 7a, the blow dryer 7e has a blower unit 71u arranged above the print medium M and a plurality of rollers 74 that contact the print medium M from below. However, the blow dryer 7 e is arranged with respect to the print medium M conveyed from the air turn bar 542 toward the roller 561 . Therefore, the plurality of nozzles 76u provided in the blower unit 71u of the blower dryer 7e face the print medium M traveling from the air turn bar 542 toward the roller 561 from above. Further, the plurality of rollers 74 of the blow dryer 7e contact the print medium M moving from the air turn bar 542 to the rollers 561 from below. In this manner, the blow dryer 7e includes a plurality of nozzles 76u arranged at equal pitches in the horizontal direction X above the print medium M, and a plurality of nozzles 76u arranged at equal pitches in the horizontal direction X below the print medium M ( and the same number of rollers 74 as the nozzles 76u. The nozzles 76u and the rollers 74 are arranged in a zigzag pattern in the horizontal direction X, as shown in FIGS. Thus, in the blow dryer 7e, the plurality of rollers 74 support the back surface M2 of the print medium M from below, while the plurality of nozzles 76u eject hot air onto the front surface M1 of the print medium M from above, thereby drying the print medium M. be done.

The blower dryer 7f is arranged downstream of the blower dryer 7e in the traveling direction of the print medium M transported from the air turn bar 542 toward the rollers 561 . Like the blow dryer 7e, the blow dryer 7f has a plurality of nozzles 76u facing the print medium M from above and a plurality of rollers 74 contacting the print medium M from below. 74 are arranged in the horizontal direction X in a zigzag pattern. Thus, in the blow dryer 7f, the plurality of rollers 74 support the back surface M2 of the print medium M from below, while the plurality of nozzles 76u eject hot air onto the front surface M1 of the print medium M from above, thereby drying the print medium M. be done.

Incidentally, each of the nozzles 76u and 76l described above extends parallel to the horizontal direction Y. As shown in FIG. In the horizontal direction Y, the width of each nozzle 76u, 76l is wider than the width of the print medium M, and the print medium M is transported so that both ends of the print medium M are positioned between the ends of the nozzles 76u, 76l. Similarly, each roller 74 extends parallel to the horizontal direction Y. As shown in FIG. In the horizontal direction Y, the width of each roller 74 is wider than the width of the print medium M, and the print medium M is conveyed so that both ends of the print medium M are positioned between both ends of the rollers 74 .

The drying device 5 also includes exhaust units 8a and 8b in the housing 6 for discharging the air in the housing 6 to the outside of the housing 6. As shown in FIG. The exhaust part 8a is arranged at the end of the other side X2 in the housing 6 and positioned between the blower dryers 7a, 7d, 7e and the side wall 6a. The exhaust part 8b is arranged at the end of the one side X1 in the housing 6 and positioned between the blower dryers 7b, 7c, 7f and the side wall 6b. These exhaust units 8a and 8b have a common configuration. The exhaust units 8a, 8b have four exhaust chambers 81 to 84 arranged in the vertical direction Z. As shown in FIG. The exhaust chamber 81 is disposed above the print medium M transported by the upper transport unit 51u, and the exhaust chamber 82 is disposed above the print medium M transported by the upper transport unit 51u and the print medium M transported by the middle transport unit 51m. The exhaust chamber 83 is arranged between the print medium M transported by the middle transport unit 51m and the print medium M transported by the lower transport unit 51l, and the exhaust chamber 84 is located between the lower transport unit It is arranged below the print medium M conveyed by 51l. Each of the exhaust chambers 81 to 84 discharges the air sucked from inside the housing 6 to the outside of the housing 6 .

Due to the exhaust from these exhaust chambers 81 to 84, an air current is generated in the housing 6 from one side to the other side in the horizontal direction Y (from the front to the back in FIG. 2). The total amount of air (exhaust amount) discharged by the exhaust chambers 81 to 84 per unit time is set according to the total amount of air (injection amount) injected by the blow dryers 7a to 7e per unit time. That is, the exhaust chambers 81 to 84 increase or decrease the respective exhaust amounts according to the increase or decrease in the injection amounts of the blower dryers 7a to 7e.

FIG. 5 is a side view schematically showing the configuration of the position adjusting section, and FIG. 6 is a plan view schematically showing the configuration of the position adjusting section. The position adjustment section 56 has rollers 561 as described above. The position adjusting section 56 also has a rotation support mechanism 563 that rotatably supports the roller 561 . The rotation support mechanism 563 has a cylindrical rotation shaft 563a parallel to the vertical direction Z and a stay 563b fixed to the housing 6. The rotation support mechanism 563 is rotatably supported by the stay 563b. . On the other hand, the roller 561 is rotatably supported by a support member 561a parallel to the horizontal direction Y, and both ends of the support member 561a protrude from the roller 561 in the horizontal direction Y. The end of the support member 561a is attached to the tip of the rotating shaft 563a. Therefore, the roller 561 can rotate in the rotation direction Rd about a straight line parallel to the vertical direction Z along with the rotation shaft 563a.

Further, the position adjusting section 56 has a drive mechanism 564 that drives the roller 561 in the rotation direction Rd. The drive mechanism 564 has an actuator 564a that moves a rod parallel to the horizontal direction X, and the rod of the actuator 564a is connected to the end of the support member 561a (the end opposite to the end to which the rotating shaft 563a is attached). It is Therefore, by driving the support member 561a by the actuator 564a, the roller 561 can be rotated in the rotation direction Rd. Here, since the rotation angle of the roller 561 is very small, the roller 561 can be rotated by being driven in the horizontal direction X by the actuator 564a.

Further, an edge sensor Sd is provided downstream of the roller 561 in the transport direction of the print medium M. As shown in FIG. This edge sensor Sd is an optical sensor that detects the position of the edge in the horizontal direction Y of the print medium M conveyed from the roller 561 . As will be described later, the rotation angle of the roller 561 by the actuator 564a is feedback-controlled based on the position of the edge of the print medium M detected by the edge sensor Sd.

Further, as shown in FIG. 5 , the position adjusting section 56 has a roller 568 between the take-up roll 12 and the roller 561 . support. That is, the print medium M is wound from the roller 561 to the winding roll 12 via the roller 568 . Also, the edge sensor Sd detects the position of the edge of the print medium M conveyed between the rollers 561 and 568 .

FIG. 7 is a block diagram showing the electrical configuration of the drying device. As shown in the figure, the drying apparatus 5 includes a control unit 100 such as a CPU (Central Processing Unit) and a storage unit 110 such as a HDD (Hard Disk Drive). The storage unit 110 stores the target position Ptd of the print medium M in the horizontal direction Y (in other words, the width direction of the print medium M). Here, the target position Ptd is the target position of the edge position of the print medium M detected by the edge sensor Sd. Then, the control unit 100 performs feedback control on the roller 561 based on this target position Ptd.

For example, the target position Ptd is set so that the center line parallel to the horizontal direction X passing through the center of the roller 561 in the horizontal direction Y and the center of the printing medium M in the horizontal direction Y are aligned. However, the specific set value of the target position Ptd is not limited to this example.

The control unit 100 inputs to the actuator 564a an operation amount corresponding to the difference between the position of the edge of the print medium M detected by the edge sensor Sd and the target position Ptd. The actuator 564a rotates the roller 561 in the rotation direction Rd by the rotation angle θd (displacement amount) corresponding to the operation amount. As a result, feedback control is performed to reduce the difference between the position of the edge of the print medium M detected by the edge sensor Sd and the target position Ptd. As a result, the position of the edge of the print medium M detected by the edge sensor Sd can be kept within a predetermined range (in other words, the steady-state deviation range) from the target position Ptd.

It should be noted that there are various ways of obtaining the rotation angle θd. For example, the rotation angle θd when the roller 561 is parallel to the horizontal direction Y may be zero degrees, the clockwise rotation in plan view may be the positive side of the rotation angle θd, and the counterclockwise rotation may be the negative side of the rotation angle θd.

As described above, in the above-described embodiment, the roller 74 (intermediate rotating member) of the lower conveying unit 51l that rotates in contact with the back surface M2 (non-printing surface) of the print medium M causes the roller 522 (previous rotating member) and the roller 561 to rotate. The print medium M conveyed between (the post-stage rotating body) is supported. Therefore, the print medium M can be stably transported in the section from the roller 522 between the upper transport section 51u and the middle transport section 51m to the roller 561 after the lower transport section 51l.

Further, the roller 74 is provided between two adjacent nozzles 76u (lower printing surface nozzles) in the lower conveying section 51l so as to face the printing medium M from below and contact the back surface M2. ing. With such a configuration, the print medium M transported by the lower transport unit 51l can be supported by the rollers 74, and the print medium M can be stably transported toward the rollers 561 behind the lower transport unit 51l.

In particular, in the lower transport section 51l, the rollers 74 are provided for each of the plurality of spaces formed in the arrangement of the plurality of nozzles 76u. In such a configuration, a plurality of nozzles 76u and a plurality of rollers 74 are arranged such that the nozzles 76u and the rollers 74 are alternately arranged one by one (that is, arranged in a zigzag pattern). Therefore, the print medium M transported by the lower transport unit 51l can be firmly supported by the plurality of rollers 74, and the print medium M can be transported extremely stably toward the rollers 561 after the lower transport unit 51l. .

Further, an edge sensor Sd (position sensor) for detecting the position of the print medium M in the horizontal direction Y (width direction) and an actuator 564a (rotator drive section) for driving the roller 561 are provided. The position of the print medium M in the horizontal direction Y is adjusted by rotating the roller 561 with the actuator 564a according to the position of the print medium M detected by the edge sensor Sd. That is, by rotating the roller 561 according to the detected position of the print medium M in the horizontal direction Y, the position of the print medium M in the horizontal direction Y is adjusted, and the transport of the print medium M is stabilized. ing. However, if the transport of the print medium M to the roller 561 is too unstable, the rotation of the roller 561 cannot sufficiently stabilize the transport of the print medium M. On the other hand, since the print medium M is supported by the rollers 74 , the print medium M is stably conveyed to the rollers 561 . As a result, the rotation of the roller 561 can sufficiently stabilize the transport of the print medium M. FIG.

In addition, the middle transport section 51m has a plurality of nozzles 76u (middle non-printing surface nozzles) arranged above the print medium M, and the nozzles 76l and the nozzles 76u are arranged in a zigzag pattern. That is, the roller 74 is not provided for the print medium M conveyed by the intermediate conveying section 51m, although the nozzle 76u is provided. In such a configuration, the print medium M before reaching the lower conveying portion 51l can be thoroughly dried by the hot air jetted from both the nozzles 76l and 76u of the middle conveying portion 51m. Therefore, both reliable drying and stable transportation of the print medium M can be achieved.

Further, a housing 6 (drying oven) that accommodates the upper conveying section 51u, the middle conveying section 51m, and the lower conveying section 51l, and exhaust sections 8a and 8b that discharge air from the housing 6 are provided. The exhaust units 8a and 8b exhaust air from the housing 6 in an amount (exhaust amount) corresponding to the amount of air (injection amount) injected from the nozzles 76u and 76l. In such a configuration, an airflow passing through the housing 6 can be generated by jetting air from the nozzles 76u and 76l and exhausting the air from the exhaust portions 8a and 8b. However, if the number of nozzles 76u and 76l is small, it may not be possible to ensure sufficient airflow. On the other hand, by providing a plurality of nozzles 76u in the middle transport section 51m, it is possible to sufficiently secure the air passing through the housing 6 and dry the print medium M firmly. Therefore, both reliable drying and stable transportation of the print medium M can be achieved.

In the embodiment described above, the printing system 1 corresponds to an example of the "printing system" of the present invention, the printing device 3 corresponds to an example of the "printing device" of the present invention, and the drying device 5 corresponds to the "printing device" of the present invention. The upper conveying unit 51u corresponds to an example of the "upper conveying unit" of the present invention, the middle conveying unit 51m corresponds to an example of the "middle conveying unit" of the present invention, and the lower conveying unit. 51l corresponds to an example of the "lower stage conveying section" of the present invention, the front folding section 52 corresponds to an example of the "front folding section" of the present invention, and the roller 522 corresponds to an example of the "front rotating body" of the present invention. The rear folding portion 54 corresponds to an example of the "lower folding portion" of the present invention, the air turn bars 541 and 542 correspond to an example of the "non-contact supporting member" of the present invention, and the roller 561 corresponds to the "lower folding portion" of the present invention. The actuator 564a corresponds to an example of the "rotating body driving section" of the present invention, the housing 6 corresponds to an example of the "drying oven" of the present invention, and the rollers of the lower conveying section 51l. 74 corresponds to an example of the "intermediate rotating body" of the present invention, the nozzle 76u of the upper transport section 51u corresponds to an example of the "upper printing surface nozzle" of the present invention, and the nozzle 76l of the middle transport section 51m of the present invention. The nozzles 76u of the middle conveying section 51m correspond to an example of the "middle non-printing surface nozzles" of the present invention, and the nozzles 76u of the lower conveying section 51l correspond to the "lower printing surface nozzles" of the present invention. The exhaust units 8a and 8b correspond to an example of the “exhaust unit” of the present invention, the edge sensor Sd corresponds to an example of the “position sensor” of the present invention, and the print medium M corresponds to an example of the “position sensor” of the present invention. The front surface M1 corresponds to an example of the "printing surface" of the present invention, the rear surface M2 corresponds to an example of the "non-printing surface" of the present invention, and the horizontal direction X corresponds to an example of the "non-printing surface" of the present invention. The one side X1 corresponds to an example of the "one side" of the invention, and the other side X2 corresponds to an example of the "other side" of the invention.

The present invention is not limited to the above-described embodiments, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the front-stage folding section 52 does not need to be composed of the two rollers 521 and 522, and may be configured to fold the printing medium M from one side X1 to the other side X2 using one large roller. Similarly, it is not always necessary to configure the rear folding portion 54 with two air turn bars 541 and 542 .

Also, the configuration of the rotation support mechanism 563 that displaces the roller 561 is not limited to the above example. In other words, the rotation support mechanism 543 may be configured such that the roller 561 is displaced by a motor instead of an actuator.

Further, the position of the center of rotation of the roller 561 is not limited to the above example, and can be changed as appropriate. Further, the displacement direction of the roller 561 is not limited to the rotation direction Rd, and the horizontal direction Y may be used.

Also, the position of the edge sensor Sd can be changed as appropriate.

Further, the arrangement and the number of rollers 74 may be appropriately changed between the rollers 522 and 561 . For example, some rollers 74 of the lower transport section 51l may be replaced with nozzles 76l. Alternatively, some or all of the nozzles 76u of the intermediate conveying section 51m may be replaced with the rollers 74. FIG. Note that the rollers 74 of the intermediate transport section 51m come into contact with the back surface M2 of the print medium M from above. Furthermore, when the rollers 74 are provided in the middle conveying portion 51m, all the rollers 74 in the lower conveying portion 51l may be replaced with the nozzles 76l.

Also, although not described in detail above, the control of the injection amount from the blower dryers 7a to 7e and the exhaust amount from the exhaust units 8a and 8b can be executed by the configuration shown in FIG. 8, for example. FIG. 8 is a block diagram showing a configuration for controlling injection quantity and exhaust quantity. A blower pump Ps is provided for the blower chambers 72u and 72l of the blower dryers 7a to 7e, and hot air generated by heating the outside air by the main heater Hm is supplied to the blower chambers 72u and 72l by the blower pump Ps. It is supplied and jetted from nozzles 76u and 76l. An exhaust pump Pe is provided for the exhaust units 8a and 8b, and the exhaust units 8a and 8b exhaust air from the housing 6 according to the operation of the exhaust pump Pe. Then, the control unit 100 controls the blower pump Ps and the exhaust pump Pe to adjust the injection amount and the exhaust amount as described above. As a result, the exhaust amount increases as the injection amount increases, while the exhaust amount decreases as the injection amount decreases.

INDUSTRIAL APPLICABILITY The present invention can be applied to all techniques for drying a print medium with ink by jetting gas.

REFERENCE SIGNS LIST 1 printing system 3 printing device 5 drying device 51u upper conveying section 51m middle conveying section 51l lower conveying section 52 front folding section 522 roller (front rotating body)
54... Post-stage folding part 541... Air turn bar (non-contact supporting member)
542 ... Air turn bar (non-contact support member)
561...Roller (latter-stage rotating body)
564a ... Actuator (rotating body driving section)
6 ... Case (drying oven)
74 Roller (intermediate rotating body)
76u... Nozzle 76l... Nozzle 8a... Exhaust part 8b... Exhaust part Sd... Edge sensor (position sensor)
M...Printing medium M1...Front surface (printing surface)
M2... Back side (non-printing side)
X...horizontal direction X1...one side X2...other side

Claims (8)

It has a plurality of upper printing surface nozzles arranged on the upper side of a long strip-shaped printing medium having a printing surface to which ink is adhered and a non-printing surface opposite to the printing surface, and the printing surface faces upward. an upper transport unit that transports the print medium to one side in the horizontal direction while ejecting gas from the upper print surface nozzles onto the print surface;
A front-stage rotating body that rotates while being in contact with the non-printing surface of the print medium is provided, and the print medium conveyed from the upper-stage conveying section is folded back to the other side opposite to the one side by the front-stage rotating body. a front folding part;
The print medium has a plurality of middle print surface nozzles arranged on the lower side of the print medium, and the print medium folded back to the other side by the front folding unit is folded with the print surface facing downward. a middle-stage conveying unit that ejects gas from the middle-stage printing-surface nozzles onto the printing surface while conveying it to the other side;
a non-contact support member that supports the print medium by injecting gas onto the print surface of the print medium, wherein the print medium conveyed from the intermediate conveying unit is pushed downward by the non-contact support member; a post-folding portion that folds back and then folds back to the one side;
The print medium has a plurality of lower print surface nozzles arranged on the upper side of the print medium, and the print medium folded back to the one side by the rear folding unit is placed on the one side with the print surface facing upward. a lower conveying unit that ejects gas from the lower printing surface nozzles onto the printing surface while conveying to the printing surface;
a post-rotating body that rotates while being in contact with the print medium conveyed from the lower conveying unit;
At least one of the middle conveying section and the lower conveying section has an intermediate rotator that rotates while being in contact with the non-printing surface of the print medium conveyed between the front rotator and the rear rotator. Device. 2. The intermediate rotating body according to claim 1, wherein the intermediate rotating body contacts the non-printing surface while facing the gap between the two adjacent lower printing surface nozzles in the lower conveying unit from below with the printing medium interposed therebetween. drying equipment. 3. The drying device according to claim 2, wherein the intermediate rotary member is provided for each of a plurality of intervals formed in the array of the plurality of lower printing surface nozzles. a position sensor that detects a position in the width direction of the print medium;
and a rotating body drive unit that drives the latter stage rotating body,
4. The drying apparatus according to claim 2, wherein the position of the print medium in the width direction is adjusted by displacing the post-rotation body with the rotation body driving unit according to the position of the print medium detected by the position sensor. Device. The middle-stage conveying unit has a plurality of middle-stage non-printing surface nozzles arranged above the print medium, the middle-stage printing surface nozzles and the middle-stage non-printing surface nozzles being arranged in a zigzag manner, A non-printing surface nozzle injects gas onto the non-printing surface;
5. The drying apparatus according to any one of claims 2 to 4, wherein the intermediate rotary body is not provided for the print medium transported by the intermediate transport section. a drying oven that accommodates the upper conveying section, the middle conveying section, and the lower conveying section;
Further comprising an exhaust unit for discharging gas from the drying furnace,
The exhaust unit exhausts from the drying furnace an amount of gas corresponding to the amount of gas ejected from the upper printing surface nozzle, the middle printing surface nozzle, the middle non-printing surface nozzle, and the lower printing surface nozzle. 6. A drying apparatus according to item 5. a printing device that prints an image by ejecting ink onto the printing surface of the printing medium;
A printing system comprising a drying device according to any one of claims 1 to 6, for drying ink ejected by the printing device and adhering to the printing surface. While injecting gas from a plurality of upper printing surface nozzles arranged on the upper side of a long band-shaped printing medium having a printing surface to which ink is adhered and a non-printing surface opposite to the printing surface, to the printing surface, conveying the print medium to one side in the horizontal direction with the print surface facing upward;
a step of folding back the print medium conveyed to the one side to the other side opposite to the one side by a front rotating body that rotates while being in contact with the non-printing surface of the print medium;
While conveying the print medium folded back to the other side to the other side with the print surface facing downward, the printing is performed from a plurality of middle print surface nozzles arranged on the lower side of the print medium. injecting a gas onto the surface;
A step of folding the print medium conveyed to the other side downward by a non-contact support member that supports the print medium by injecting gas onto the printing surface of the print medium, and then folding it back to the one side. When,
While conveying the print medium folded back to the one side to the one side with the print surface facing upward, from a plurality of lower print surface nozzles arranged above the print medium onto the print surface. a step of injecting a gas;
a step of conveying the print medium conveyed to the one side by a post-stage rotating body that rotates while being in contact with the print medium;
A drying method in which the print medium conveyed between the preceding stage rotator and the latter stage rotator is supported by an intermediate rotator that rotates while being in contact with the non-printing surface of the print medium.

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