Drying device, printing system and drying method

Abstract

To stably transport a printing medium in a floating transport 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 transport parts in order.SOLUTION: A position of a printing medium M in a horizontal direction Y (width direction) is adjusted by rotating (displacing) a roller 561 according to the result of detection of the position of the printing medium M in the horizontal direction Y by an edge sensor Sd, to stabilize transportation of the printing medium M. Also, the position of the printing medium M in the horizontal direction Y is adjusted by rotating air turn bars 541, 542 that turn the printing medium M between the rollers 522 and 561. Consequently, a rotation angle required for the roller 561 can be made smaller. As a result, the printing medium M can be stably transported in a floating transport section from the rollers 522 to the rollers 561.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a technique for drying a print medium having ink attached thereto by jetting gas. [Background technology]

[0002] Patent Document 1 shows a drying device that dries a print medium by spraying gas from a nozzle onto the print medium to which ink has been attached. In particular, this drying device has three transport sections arranged vertically, and each transport section transports the print medium horizontally, so that the print medium passes through the upper transport section, the middle transport section, and the lower transport section in that order. Specifically, the upper transport section transports the print medium to one side, the middle transport section located below the upper transport section transports the print medium to the other side, and the lower transport section located below the middle transport section 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, respectively, and sprays gas from these nozzles. This allows the print medium to be dried while being transported without coming into contact with the print medium.

[0003] In addition, two rollers are arranged vertically between the upper conveying section and the middle conveying section, and the print medium conveyed from the upper conveying section to one side is folded downward by the upper roller, then folded back to the other side by the lower roller, and proceeds to the middle conveying section. Two air turn bars are arranged vertically between the middle conveying section and the lower conveying section, and the print medium conveyed from the middle conveying section to the other side is folded downward by the upper air turn bar, then folded back to one side by the lower air turn bar, and proceeds to the lower conveying section. Furthermore, rollers are arranged behind the lower conveying section (in other words, downstream in the conveying direction of the print medium), and the print medium conveyed from the lower conveying section to one side is supported by the rollers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-148383 A Summary of the Invention [Problem to be solved by the invention]

[0005] In this drying device, the print medium is transported by floating transport between the front-stage rotating body (roller) provided between the upper transport section and the middle transport section, and the rear-stage rotating body (roller) provided after the lower transport section, so there are no members that come into contact with the print medium. As a result, the print medium is not transported straight in this section, and the print medium may become biased in the width direction or fall off the nozzle.

[0006] This invention has been developed in consideration of the above-mentioned problems, and aims to stably transport the printing medium in the floating transport section from the front rotating body between the upper and middle transport sections to the rear rotating body behind the lower transport section when drying the printing medium while transporting the printing medium so that it passes through the upper, middle and lower transport sections in order. [Means for solving the problem]

[0007] The drying device according to the present invention comprises an upper transport section that transports a long strip-shaped print medium having a printed surface with ink attached and a non-printed surface opposite the printed surface to one side in a horizontal direction with the printed surface facing up, a front-stage rotating body that rotates while contacting the non-printed surface of the print medium, and a front-stage folding section that folds the print medium transported from the upper transport section downward by the front-stage rotating body and then folds it back to the other side opposite the one side, a middle transport section that transports the print medium folded to the other side by the front-stage folding section with the printed surface facing down, and a printing device for printing the print medium. The printing apparatus includes a rear-stage folding section that has a non-contact support member that supports the printing medium by injecting gas onto the printing surface, and that folds the printing medium transported from the middle-stage transport section downward by the non-contact support member and then folds it back to one side, a lower-stage transport section that transports the printing medium that has been folded back to one side by the rear-stage folding section to the one side with the printing surface facing up, a first position sensor that detects the position of the printing medium in the width direction, a rear-stage rotating body that rotates while in contact with the printing medium transported from the lower-stage transport section, and a rotating body drive section that drives the rear-stage rotating body, and the first position sensor and a position adjustment unit that adjusts the widthwise position of the print medium by displacing the rear stage rotor using the rotor drive unit in accordance with the detected position of the print medium, the upper stage transport unit has a plurality of upper stage printed surface nozzles arranged above the print medium and sprays gas onto the print surface from the upper stage printed surface nozzles, and the middle stage transport unit has a plurality of middle stage printed surface nozzles arranged below the print medium and a plurality of middle stage non-printed surface nozzles arranged above the print medium, spraying gas onto the print surface of the print medium from the middle stage printed surface nozzles and spraying gas onto the non-printed surface from the middle stage non-printed surface nozzles. The printing medium is transported without contacting the printing medium, the lower stage transport unit has a plurality of lower stage printing surface nozzles arranged above the printing medium and a plurality of lower stage non-printing surface nozzles arranged below the printing medium, and gas is sprayed onto the printing surface of the printing medium from the lower stage printing surface nozzles and onto the non-printing surface from the lower stage non-printing surface nozzles, thereby transporting the printing medium without contacting the printing medium, and the rear stage folding unit further has a support member drive unit that displaces the non-contact support member, and the widthwise position of the printing medium is adjusted by displacing the non-contact support member with the support member drive unit.

[0008] The drying method according to the present invention includes the steps of: transporting a long strip-shaped printing medium, having a printing surface with ink attached and a non-printing surface opposite the printing surface, to one side in a horizontal direction with the printing surface facing up, while spraying gas onto the printing surface from a plurality of upper stage printing surface nozzles arranged above the printing medium; folding back the printing medium transported to one side downward by a front stage rotating body that rotates while contacting the non-printing surface of the printing medium, and then folding back the printing medium to the other side opposite the one side; transporting the printing medium that has been folded back to the other side with the printing surface facing down, while spraying gas onto the printing surface of the printing medium from a plurality of middle stage printing surface nozzles arranged below the printing medium and spraying gas onto the non-printing surface from a plurality of middle stage non-printing surface nozzles arranged above the printing medium, thereby supporting the printing medium without contacting it; The method includes a step of folding the print medium downward and then folding it back to one side by a non-contact support member that supports the print medium by spraying gas onto the printing surface of the print medium; a step of transporting the print medium folded back to one side to one side with the printing surface facing upward, and supporting the print medium without contacting the print medium by spraying gas onto the printing surface of the print medium from a plurality of lower printing surface nozzles arranged above the print medium and spraying gas onto the non-printing surface from a plurality of lower non-printing surface nozzles arranged below the print medium; and a step of transporting the print medium that has been transported to one side by a rear-stage rotating body that rotates while in contact with the print medium, wherein the widthwise position of the print medium is adjusted by displacing the non-contact support member, and the widthwise position of the print medium is adjusted by displacing the rear-stage rotating body in accordance with the result of detecting the widthwise position of the print medium.

[0009] In the present invention (drying device and drying method) configured as described above, the print medium is transported by floating transport in a long section, in which the print medium is transported from the front-stage rotating body to the other side, then the non-contact support member turns the print medium back to one side, and the print medium is transported to the rear-stage rotating body. Therefore, the rear-stage rotating body is displaced according to the result of detecting the widthwise position of the print medium, thereby adjusting the widthwise position of the print medium, thereby stabilizing the transport of the print medium. However, if the transport of the print medium over such a long section is adjusted only by the displacement of the rear-stage rotating body, the displacement amount required for the rear-stage rotating body may become excessive, making it difficult to stabilize the transport of the print medium. In response to this, in the present invention, the non-contact support member that turns the print medium back between the front-stage rotating body and the rear-stage rotating body is displaced to adjust the widthwise position of the print medium. This makes it possible to suppress the displacement amount required for the rear-stage rotating body. As a result, it is possible to stably transport the print medium in the floating transport section from the front-stage rotating body to the rear-stage rotating body.

[0010] The drying device may be configured to further include a second position sensor that detects the position of the print medium in the width direction, and in the direction in which the print medium is transported, the first position sensor detects the position of the print medium downstream of the rear-stage folding unit, the second position sensor detects the position of the print medium upstream of the first position sensor, and the rear-stage folding unit adjusts the position of the print medium in the width direction by displacing the non-contact support member using the support member drive unit in accordance with the position of the print medium detected by the second position sensor. In this configuration, the non-contact support member can be displaced based on the position of the print medium detected by the second position sensor to optimize the transport position of the print medium, while the rear-stage rotating body can be displaced based on the position of the print medium detected by the first position sensor to optimize the transport position of the print medium. This makes it possible to stably transport the print medium in the floating transport section from the front-stage rotating body to the rear-stage rotating body.

[0011] The drying device may be configured such that the rear folding unit executes feedback control to displace the non-contact support member by the support member drive unit so as to reduce the difference between the position of the print medium detected by the second position sensor and the target position of the print medium, and the target position in the feedback control is set according to the displacement amount of the rear-stage rotor displaced by the rotor drive unit. In this configuration, the target position (target value) in the feedback control to displace the non-contact support member based on the position of the print medium detected by the second position sensor is set according to the displacement amount of the rear-stage rotor. Therefore, it is possible to execute control such as suppressing the displacement amount of the rear-stage rotor by shifting the target position of the feedback control in the displacement direction of the rear-stage rotor. Therefore, it is possible to stably transport the print medium in the floating transport section from the front-stage rotor to the rear-stage rotor.

[0012] The drying device may be configured such that in the rear folding section, an upper non-contact support member and a lower non-contact support member disposed below the upper non-contact support member are each provided as a non-contact support member, the print medium is folded downward by the upper non-contact support member and then folded to one side by the lower non-contact support member, and the second position sensor detects the position of the print medium between the upper non-contact support member and the lower non-contact support member. In this configuration, the position of the print medium detected by the second position sensor can be accurately adjusted according to the amount of displacement of the upper and lower non-contact support members.

[0013] The drying device may further include a storage unit that stores displacement amount information indicating a correspondence relationship between a rotor displacement amount, which is a displacement amount of the rear-stage rotor, and a support member displacement amount, which is a displacement amount of the non-contact support member obtained when the rear-stage rotor is displaced by the rotor displacement amount, and the rear-stage folding unit displaces the non-contact support member by the support member displacement amount associated by the displacement amount information with respect to the rotor displacement amount of the rear-stage rotor displaced by the rotor drive unit. In this configuration, the displacement amount of the rear-stage rotor is adjusted according to the position of the print medium detected by the first position sensor, and the displacement amount of the non-contact support member is adjusted according to the displacement amount of the rear-stage rotor. Therefore, there is no need to provide a position sensor separate from the first position sensor to adjust the displacement amount of the non-contact support member. Therefore, the configuration can be simplified and costs can be reduced.

[0014] The drying device may further include a storage unit that stores displacement amount information indicating a correspondence relationship between the detected position by the first position sensor and the support member displacement amount, which is the displacement amount of the non-contact support member obtained when the first position sensor indicates the detected position, and the rear folding unit displaces the non-contact support member by the support member driving unit by the support member displacement amount associated by the displacement amount information with respect to the detected position indicated by the first position sensor. In such a configuration, the displacement amount of the rear rotating body is adjusted according to the position of the print medium detected by the first position sensor, and the displacement amount of the non-contact support member is also adjusted according to the position of the print medium detected by the first position sensor. Therefore, there is no need to provide a position sensor separate from the first position sensor to adjust the displacement amount of the non-contact support member. This simplifies the configuration and reduces costs.

[0015] The drying device may be configured so that the distance along the print medium from the first position sensor to the rear-stage rotating body is shorter than the distance along the print medium from the first position sensor to the rear-stage turning part. In such a configuration, the first position sensor is disposed close to the rear-stage rotating body. Therefore, the position of the print medium detected by the first position sensor can be accurately adjusted according to the displacement amount of the rear-stage rotating body. As a result, the position of the print medium can be optimized over the entire floating transport section from the front-stage rotating body to the rear-stage rotating body.

[0016] The drying device may also be configured such that the first position sensor detects the position of the print medium downstream of the rear rotor in the direction in which the print medium is transported. In this configuration, the displacement of the rear rotor is adjusted based on the position of the print medium detected by the first position sensor provided after the floating transport section from the front rotor to the rear rotor. As a result, the position of the print medium can be optimized over the entire floating transport section from the front rotor to the rear rotor.

[0017] The drying device may further include a storage unit that stores displacement amount information indicating a correspondence relationship between the type of print medium and the displacement amount of the non-contact support member required to transport the print medium of that type, and the rear folding unit displaces the non-contact support member by the support member drive unit by the displacement amount corresponding to the type of print medium being transported by the displacement amount information. In this configuration, the position of the print medium in the width direction is adjusted by displacing the non-contact support member according to the type of print medium. This makes it possible to reduce the displacement amount required for the rear rotating body. As a result, it is possible to stably transport the print medium in the floating transport section from the front rotating body to the rear rotating body.

[0018] The printing system according to the present invention includes a printing device that prints an image by ejecting ink onto the printing surface of a printing medium, and the above-mentioned drying device that dries the ink ejected by the printing device and attached to the printing surface. Therefore, when drying the printing medium while transporting the printing medium so that it passes through the upper, middle, and lower transport units in order, it becomes possible to stably transport the printing medium in the floating transport section from the front rotor between the upper and middle transport units to the rear rotor behind the lower transport unit. Effect of the Invention

[0019] As described above, according to the present invention, when drying a printing medium while transporting the printing medium so that it passes through the upper, middle and lower transport sections in order, it is possible to stably transport the printing medium in the floating transport section from the front rotor between the upper and middle transport sections to the rear rotor behind the lower transport section. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a front view showing a schematic diagram of an example of a printing system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a front view showing a drying device provided in the printing system of FIG. 1. [Diagram 3] FIG. 4 is a partially enlarged schematic view showing the air blower dryer of the upper conveying section. [Figure 4] 4 is a partially enlarged schematic view showing the air blow dryers of the middle conveying section and the lower conveying section; FIG. [Diagram 5] FIG. 4 is a side view showing a schematic configuration of a rear folding section. [Figure 6] FIG. 4 is a plan view showing a schematic configuration of a rear folding section. [Figure 7] FIG. 4 is a side view illustrating a schematic configuration of a position adjustment unit. [Figure 8] FIG. 4 is a plan view illustrating a schematic configuration of a position adjustment unit. [Figure 9] FIG. 2 is a block diagram showing an electrical configuration of the drying device according to the first embodiment. [Figure 10]FIG. 11 is a diagram illustrating target position control information used in a drying device according to a second embodiment in the form of a table. [Figure 11] FIG. 11 is a block diagram showing an electrical configuration of a drying device according to a third embodiment. [Figure 12] FIG. 13 is a diagram showing rotation angle information used in the third embodiment in a table format. [Figure 13] 13 is a flowchart showing an example of a method for acquiring the rotation angle information in FIG. 12. [Figure 14] FIG. 13 is a diagram illustrating rotation angle information used in the fifth embodiment in a table format. [Figure 15] FIG. 4 is a block diagram showing a configuration for controlling an injection amount and an exhaust amount. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1 is a front view showing a schematic example of a printing system according to the present invention. In FIG. 1 and the following figures, a horizontal direction X, a horizontal direction Y perpendicular to the horizontal direction X, and a vertical direction Z are appropriately shown. As shown in FIG. 1, the printing system 1 has a configuration in which an application device 2, a printing device 3, and a drying device 5 are arranged in this order in the horizontal direction X (arrangement direction). In this printing system 1, while conveying a long strip-shaped printing medium M from a pay-out roll 11 to a take-up roll 12 in a roll-to-roll manner, the printing device 3 prints an image on the printing medium M coated with a coating liquid by the application device 2 using an inkjet method, and the drying device 5 dries the printing medium M on which the image has been printed. The material of the printing medium M is a film such as OPP (oriented polypropylene) or PET (polyethylene terephthalate). However, the material of the printing medium M is not limited to a film, and may be paper or the like. Such a printing medium M is flexible. In the following description, the surface of the print medium M on which an image is printed will be referred to as the front surface M1, and the surface opposite the front surface M1 will be referred to as the back surface M2.

[0022] The coating device 2 has 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 conveying section 23 that conveys the print medium M. The coating device 2 has a coating area where the gravure roller 22 contacts the print medium M conveyed by the conveying section 23 from below, and the conveying section 23 conveys the print medium M along the coating area while facing the surface M1 of the print medium M downward. Meanwhile, the gravure roller 22 supplies the primer to the coating area by rotating while holding the primer on its circumferential surface. In this way, the primer supplied by the gravure roller 22 is applied to the surface M1 of the print medium M in the coating area. In addition, in the coating area, the traveling direction of the print medium M and the rotation direction of the circumferential surface of the gravure roller 22 are opposite. In other words, the primer is applied to the print medium M by a so-called reverse kiss method. Then, the transport section 23 transports the printing medium M from the coating device 2 to the printing device 3 while facing the surface M1 of the printing medium M on which the primer has been applied upward.

[0023] The printing device 3 comprises a housing 31, a color printing unit 32 arranged within the housing 31, a white printing unit 33 arranged above the color printing unit 32 within the housing 31, and a transport unit 34 that transports the printing medium M using a number of rollers arranged within the housing 31.

[0024] The color printing unit 32 has a plurality of (six) ejection heads 321 arranged in the traveling direction of the printing medium M above the printing medium M transported by the transport unit 34. The plurality of ejection heads 321 have nozzles facing from above the surface M1 of the printing medium M passing below each of them, and eject color inks of different colors from the nozzles by an inkjet method. Here, color ink means ink other than white, and includes inks such as cyan, magenta, yellow, and black. In this way, the plurality of ejection heads 321 of the color printing unit 32 print a color image on the surface M1 of the printing medium M by ejecting color inks from above onto the surface M1 of the printing medium M passing below each of them.

[0025] The white printing unit 33 also has a single ejection head 331 arranged above the printing medium M transported by the transport unit 34. The ejection head 331 has nozzles facing from above the surface M1 of the printing medium M passing below it, 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 it.

[0026] The printing medium M is carried from the coating device 2 to the housing 31 of the printing device 3 with the surface M1 facing upward. Meanwhile, the transport unit 34 turns the printing medium M carried into the housing 31 upside down twice, and then transports the printing medium M to the color printing unit 32. This allows each ejection head 321 of the color printing unit 32 to eject color inks onto the surface M1 of the printing medium M facing upward. Furthermore, the transport unit 34 turns the printing medium M with the color inks attached upside down twice, and then transports the printing medium M to the white printing unit 33. This allows the ejection head 331 of the white printing unit 33 to eject white ink onto the surface M1 of the printing medium M facing upward. In this way, the printing medium M with the color inks and white ink attached to its surface M1 is transported from the printing device 3 to the drying device 5 by the transport unit 34.

[0027] 2 is a front view showing a drying device provided in the printing system of FIG. 1. In the figure, one side X1 and the other side X2 of the horizontal direction X are shown, and the one side X1 and the other side X2 face opposite each other. The drying device 5 dries the printing medium M while appropriately folding back and transporting the printing medium M in the horizontal direction X. 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, 6b of the housing 6 in the horizontal direction X are parallel to the vertical direction Z and perpendicular to the horizontal direction X, and face each other with a gap in between in the horizontal direction X.

[0028] Of the side walls 6a and 6b, an inlet 61 penetrates the side wall 6a on the other side X2 in the horizontal direction X (the side facing the printing device 3) in the horizontal direction X, and an outlet 66 penetrates the housing 6b on one side X1 in the horizontal direction X (the opposite side to the printing device 3) in the horizontal direction X. The printing medium M discharged from the printing device 3 is carried into the housing 6 through the inlet 61 and then discharged to the outside of the housing 6 through the outlet 66.

[0029] That is, the drying device 5 includes a transport section 51 for transporting the printing medium M in the housing 6, and the transport section 51 transports the printing medium M from the inlet 61 to the outlet 66. The transport section 51 has an upper transport section 51u for transporting the printing medium M from the other side X2 to the one side X1, a middle transport section 51m for transporting the printing medium M from the one side X1 to the other side X2, and a lower transport section 51l for transporting the printing medium M from the other side X2 to the one side X1. The middle transport section 51m is disposed below the upper transport section 51u, and the lower transport section 51l is disposed below the middle transport section 51m. Therefore, the printing medium M transported by the upper transport section 51u, the printing medium M transported by the middle transport section 51m, and the printing medium M transported by the lower transport section 51l are aligned in the vertical direction Z, in other words, overlap each other when viewed from the vertical direction Z. Specifically, the upper conveying unit 51u conveys the printing medium M at the same height as the entrance 61, and the printing medium M is conveyed in the horizontal direction X by the upper conveying unit 51u with the front surface M1 facing upward and the back surface M2 facing downward. The middle conveying unit 51m conveys the printing medium M below the upper conveying unit 51u, and the printing medium M is conveyed 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. The lower conveying unit 51l conveys the printing medium M below the middle conveying unit 51m, and the printing medium M is conveyed in the horizontal direction X by the lower conveying unit 51l with the front surface M1 facing upward and the back surface M2 facing downward.

[0030] The transport section 51 also has a front-stage folding section 52 that folds the printing medium M from the upper-stage transport section 51u to the middle-stage transport section 51m. The front-stage folding section 52 has two rollers 521, 522 arranged in the vertical direction Z on one side X1 of the housing 6. Each of the rollers 521, 522 is arranged parallel to the horizontal direction Y and is supported by the housing 6 around a rotation axis parallel to the horizontal direction Y. Of the rollers 521, 522, the upper roller 521 wraps the back surface M2 of the printing medium M transported to the one side X1 by the upper-stage transport section 51u around it and folds the printing medium M downward, and the lower roller 522 wraps the back surface M2 of the printing medium M folded downward by the roller 521 around it and folds the printing medium M back to the other side.

[0031] In this way, the front surface M1 and the back surface M2 of the printing medium M are inverted upside down by folding the printing medium M from one side X1 to the other side X2 by the front-stage folding unit 52. The printing medium M folded to the other side X2 by the front-stage folding unit 52 is transported to the other side X2 by the middle-stage transport unit 51m.

[0032] The transport section 51 also has a rear-stage folding section 54 that folds the print medium M from the middle-stage transport section 51m to the lower-stage transport section 51l. The rear-stage folding section 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 transported from the middle-stage transport section 51m toward the other side X2. As a result, the air turn bar 541 bends the print medium M downward with a gap between it and the surface M1 of the print medium M. Of the air turn bars 541 and 542, the lower air turn bar 542 injects air onto the surface M1 of the print medium M transported downward from the air turn bar 541. As a result, the air turn bar 542 bends the print medium M to one side X1 while leaving a gap between the air turn bar 542 and the surface M1 of the print medium M.

[0033] In this way, the rear-stage folding unit 54 folds the printing medium M from the other side X2 to the one side X1, thereby vertically inverting the front side M1 and the back side M2 ​​of the printing medium M. The printing medium M folded back to the one side X1 by the rear-stage folding unit 54 is transported to the one side X1 by the lower-stage transport unit 51l.

[0034] The transport unit 51 also has a roller 561 that supports the printing medium M transported from the lower transport unit 51l to the one side X1. The roller 561 is disposed parallel to the horizontal direction Y on the one side X1 of the housing 6, and is supported by the housing 6 so as to be rotatable about an axis of rotation parallel to the horizontal direction Y. The roller 561 supports the printing medium M by rotating while contacting the back surface M2 of the printing medium M transported from the lower transport unit 51l to the one side X1. The roller 561 constitutes a part of a position adjustment mechanism 56 that adjusts the position of the printing medium M in the horizontal direction Y, as described later.

[0035] The drying device 5 includes six air dryers 7a to 7f in the housing 6. Of these, two air dryers 7a and 7b are provided in the upper conveying section 51u and arranged between the inlet 61 and the roller 521. The air dryers 7a and 7b dry the printing medium M transported from the inlet 61 to the roller 521. The two air dryers 7c and 7d are provided in the middle conveying section 51m and arranged between the roller 522 and the air turn bar 541. The air dryers 7c and 7d dry the printing medium M transported from the roller 522 to the air turn bar 541. The two air dryers 7e and 7f are provided in the lower conveying section 51l and arranged between the air turn bar 542 and the roller 561. The air blowers 7e and 7f dry the print medium M transported from the air turn bar 542 toward the roller 561.

[0036] Fig. 3 is a schematic diagram showing a partially enlarged view of the air blow dryer in the upper conveying section, and Fig. 4 is a schematic diagram showing a partially enlarged view of the air blow dryers in each of the middle conveying section and the lower conveying section. Next, the air blow dryers 7a to 7f will be described with reference to Figs. 3 and 4.

[0037] The blower dryer 7a has a blower unit 71u arranged above the printing medium M transported from the carry-in entrance 61 toward the roller 521. The blower unit 71u has a blower chamber 72u extending in the horizontal direction X above the printing medium M. Both end faces of the blower chamber 72u in the horizontal direction X are planes perpendicular to the horizontal direction X and parallel to the vertical direction Z. The blower chamber 72u is supplied with hot air (air of 60 degrees or more) generated by heating air with a heater provided outside the printing system 1. The lower surface of the blower chamber 72u is a nozzle arrangement plane 73u that faces from above the surface M1 (upper surface) of the printing medium M facing upward. This nozzle arrangement plane 73u is a plane parallel to the horizontal direction X and perpendicular to the vertical direction Z. 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 multiple nozzles 76u are lined up between the nozzle arrangement plane 73u and the surface M1 of the printing medium M, and face the surface M1 of the printing medium M. Each nozzle 76u is in communication with the air blowing chamber 72u, and hot air supplied to the air blowing chamber 72u is sprayed from the nozzles 76u onto the surface M1 of the printing medium M, drying the printing medium M. In this way, of the multiple air blowing dryers 7a to 7f, the air blowing dryer 7a dries the printing medium M carried into the housing 6 first.

[0038] Furthermore, the blower dryer 7a has multiple rollers 74 (the same number as the nozzles 76u) arranged below the print medium M transported from the carry-in entrance 61 toward the rollers 521. The multiple 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 supports the print medium M from below while rotating in response to the print medium M about an axis of rotation parallel to the horizontal direction Y. In addition, the rollers 74 are provided with fine spiral grooves, which make it easier for air to escape between the print medium M and the peripheral surface of the rollers 74.

[0039] Incidentally, the nozzle 76u faces from above the range between two adjacent rollers 74 in the horizontal direction X, and the roller 74 faces from below the range between the upper two adjacent nozzles 76u in the horizontal direction X. 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 staggered pattern.

[0040] 3, in the portion of the printing medium M facing the nozzle 76u, the printing medium M is pushed downward by the hot air from the nozzle 76u, so that the printing medium M is biased downward from the upper end of the roller 74, and the portion of the printing medium M facing the roller 74 is supported by the roller 74. Therefore, the printing medium M is transported in the horizontal direction X from the other side X2 to the one side X1 while undulating between the upper end of the roller 74 and below the upper end.

[0041] The air blower 7b is disposed downstream of the air blower 7a in the traveling direction of the printing medium M transported from the carry-in entrance 61 toward the rollers 521. Like the air blower 7a, the air blower 7b has an air blowing unit 71u disposed above and multiple rollers 74 disposed below the printing medium M transported from the carry-in entrance 61 toward the rollers 521. In the air blower 7b, the multiple rollers 74 support the back surface M2 of the printing medium M from below, while multiple nozzles 76u of the air blowing unit 71u (the same number as the rollers 74) spray hot air from above onto the front surface M1 of the printing medium M, thereby drying the printing medium M.

[0042] The air blowing dryer 7c has air blowing units 71u and 71l arranged above and below the print medium M transported from the roller 522 to the air turn bar 541. The upper air blowing unit 71u has an air blowing chamber 72u extending in the horizontal direction X above the print medium M. Both end faces of the air blowing chamber 72u in the horizontal direction X are planes perpendicular to the horizontal direction X and parallel to the vertical direction Z. The above-mentioned hot air is supplied to the air blowing chamber 72u. The lower surface of the air blowing chamber 72u is a nozzle arrangement plane 73u that faces from above the rear surface M2 (upper surface) of the print medium M facing upward. This nozzle arrangement plane 73u is a plane parallel to the horizontal direction X and perpendicular to the vertical direction Z. Furthermore, the air blowing 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 multiple nozzles 76u are lined up between the nozzle arrangement plane 73u and the back surface M2 of the printing medium M, and face the back surface M2 of the printing medium M. Each nozzle 76u is in communication with the air blowing chamber 72u, and hot air supplied to the air blowing chamber 72u is sprayed from the nozzles 76u onto the back surface M2 of the printing medium M.

[0043] The lower blowing unit 71l has a blowing chamber 72l extending in the horizontal direction X below the printing medium M. Both end faces 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. The above-mentioned hot air 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 printing medium M facing downward from below. This nozzle arrangement plane 73l is a plane that is parallel to the horizontal direction X and perpendicular to the vertical direction Z. Furthermore, the blowing unit 71l has a plurality of nozzles 76l arranged at a predetermined pitch in the horizontal direction X on this nozzle arrangement plane 73l. In this way, the plurality of nozzles 76l are lined up between the nozzle arrangement plane 73l and the surface M1 of the printing medium M, and face the surface M1 of the printing medium M. Each nozzle 76l is in communication with the air blowing chamber 72l, and the hot air supplied to the air blowing chamber 72l is sprayed onto the surface M1 of the printing medium M from the nozzles 76l.

[0044] In this manner, the air blowing units 71u and 71l sandwich the printing medium M. In other words, the printing medium M transported by the middle-stage transport section 51m passes between the air blowing units 71u and 71l. In this manner, the air blowing dryer 7c dries the printing medium M by spraying hot air from the air blowing units 71u and 71l on both the upper and lower sides toward the printing medium M transported by the middle-stage transport section 51m.

[0045] Incidentally, the upper nozzle 76u faces the range between the two lower nozzles 76l adjacent to each other in the horizontal direction X from above, and the lower nozzle 76l faces the range between the two upper nozzles 76u adjacent to each other in the horizontal direction X from below. That is, 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, 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, 76l are arranged in a staggered manner. Such a staggered arrangement of the nozzles 76u, 76l is realized by shifting the positions of the blower chambers 72u, 72l from each other in the horizontal direction X.

[0046] 4, in the portion of the printing medium M facing the upper nozzle 76u, the printing medium M is pushed downward by the hot air from the nozzle 76u, so that the printing medium M is biased downward from the transport center line L, and in the portion of the printing medium M facing the lower nozzle 76l, the printing medium M is pushed upward by the hot air from the nozzle 76l, so that the printing medium M is biased upward from the transport center line L. Here, the transport center line L is a horizontal imaginary straight line that is equidistant from each of the nozzles 76u and 76l in the vertical direction Z. Therefore, the printing medium M is transported in the horizontal direction X from one side X1 to the other side X2 while undulating between above and below the transport center line L.

[0047] The air blower 7d is disposed downstream of the air blower 7c in the traveling direction of the print medium M transported from the roller 522 toward the air turn bar 541. Like the air blower 7c, the air blower 7d has air blowing units 71u and 71l that sandwich the print medium M in the vertical direction Z. In the air blower 7d, the air blowing unit 71u sprays hot air from above onto the back surface M2 of the print medium M, and the air blowing unit 71l sprays hot air from below onto the front surface M1 of the print medium M, thereby drying the print medium M.

[0048] Similar to the air blower 7c, the air blower 7e has air blowing units 71u and 71l that sandwich the printing medium M in the vertical direction Z. However, since the air blower 7e is disposed relative to the printing medium M transported from the air turn bar 542 to the rollers 561, the air blowing units 71u and 71l of the air blower 7e sandwich the printing medium M transported from the air turn bar 542 to the rollers 561 in the vertical direction Z. In the air blower 7e, the air blowing unit 71u sprays hot air from above onto the front surface M1 of the printing medium M, and the air blowing unit 71l sprays hot air from below onto the back surface M2 of the printing medium M, thereby drying the printing medium M.

[0049] The air blower 7f is disposed downstream of the air blower 7e in the traveling direction of the printing medium M transported from the air turn bar 542 toward the roller 561. This air blower 7f has air blowing units 71u and 71l that sandwich the printing medium M in the vertical direction Z, similar to the air blower 7e. In the air blower 7f, the air blowing unit 71u sprays hot air from above onto the front surface M1 of the printing medium M, and the air blowing unit 71l sprays hot air from below onto the back surface M2 of the printing medium M, thereby drying the printing medium M.

[0050] Incidentally, the nozzles 76u, 76l described above are provided to extend parallel to the horizontal direction Y. In the horizontal direction Y, the width of each nozzle 76u, 76l is wider than the width of the printing medium M, and the printing medium M is transported so that both ends of the printing medium M are located between both ends of the nozzles 76u, 76l. Similarly, each roller 74 is provided to extend parallel to the horizontal direction Y. In the horizontal direction Y, the width of each roller 74 is wider than the width of the printing medium M, and the printing medium M is transported so that both ends of the printing medium M are located between both ends of the roller 74.

[0051] As described above, the air blowing dryers 7a and 7b of the upper conveying section 51u convey the print medium M in the horizontal direction X by a plurality of rollers 74 arranged in the horizontal direction X. On the other hand, the air blowing dryers 7c and 7d of the middle conveying section 51m and the air blowing dryers 7e and 7f of the lower conveying section 51l perform floating conveyance to convey the print medium M by injecting air to the print medium M by a pair of air blowing units 71u and 71l sandwiching the print medium M from the vertical direction Z. In addition, the rear turn-back section 54 between the middle conveying section 51m and the lower conveying section 51l also conveys the print medium M by floating conveyance by the air turn bars 541 and 542. Therefore, the print medium M conveyed between the roller 522 and the roller 561 is not in contact with members such as rollers. In other words, the section from the roller 522 to the roller 561 is a floating conveyance section in which there are no members (rollers, etc.) that contact the print medium M.

[0052] The drying device 5 further includes exhaust units 8a, 8b in the housing 6 for discharging air from the housing 6 to the outside. The exhaust unit 8a is disposed at an end of the other side X2 in the housing 6, and is located between the blower dryers 7a, 7d, 7e and the side wall 6a. The exhaust unit 8b is disposed at an end of the one side X1 in the housing 6, and is located between the blower dryers 7b, 7c, 7f and the side wall 6b. These exhaust units 8a, 8b have a common configuration. The exhaust units 8a, 8b have four exhaust chambers 81-84 arranged in the vertical direction Z. The exhaust chamber 81 is disposed above the printing medium M transported by the upper-stage transport unit 51u, the exhaust chamber 82 is disposed between the printing medium M transported by the upper-stage transport unit 51u and the printing medium M transported by the middle-stage transport unit 51m, the exhaust chamber 83 is disposed between the printing medium M transported by the middle-stage transport unit 51m and the printing medium M transported by the lower-stage transport unit 51l, and the exhaust chamber 84 is disposed below the printing medium M transported by the lower-stage transport unit 51l. Each of the exhaust chambers 81 to 84 exhausts air sucked from inside the housing 6 to the outside of the housing 6.

[0053] The exhaust of these exhaust chambers 81-84 generates an airflow 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) exhausted by the exhaust chambers 81-84 per unit time is set according to the total amount of air (injection amount) sprayed by the blower dryers 7a-7e per unit time. In other words, the exhaust chambers 81-84 increase or decrease their respective exhaust amounts according to an increase or decrease in the injection amount of the blower dryers 7a-7e.

[0054] FIG. 5 is a side view showing the configuration of the rear-stage folding unit, and FIG. 6 is a plan view showing the configuration of the rear-stage folding unit. As described above, the rear-stage folding unit 54 has two air turn bars 541 and 542 arranged in the vertical direction Z. The peripheral surfaces 541a and 542a of the air turn bars 541 and 542 are curved surfaces having a sector shape when viewed from the horizontal direction Y, and have a plurality of holes. The air turn bars 541 and 542 support the printing medium M while lifting the printing medium M from the peripheral surfaces 541a and 542a by injecting air to the printing medium M from the holes of the peripheral surfaces 541a and 542a. In this way, the printing medium M wrapped around the peripheral surfaces 541a and 542a of the air turn bars 541 and 542 with a gap therebetween is transported from the peripheral surface 541a of the air turn bar 541 to the peripheral surface 542a of the air turn bar 542.

[0055] The rear folding section 54 also has a rotation support mechanism 543 that rotatably supports the air turn bar 541 and the air turn bar 542. The rotation support mechanism 543 has a cylindrical rotation shaft 543a parallel to the vertical direction Z and a stay 543b fixed to the housing 6, and the rotation shaft 543a is rotatably supported by the stay 543b. Furthermore, the rotation support mechanism 543 has two mounting members 543c attached to both ends of the rotation shaft 543a, and the two mounting members 543c are attached to the end faces of the air turn bars 541 and 542, respectively. Therefore, the air turn bars 541 and 542 can rotate in a rotation direction Ru around a straight line parallel to the vertical direction Z along with the rotation shaft 543a.

[0056] Furthermore, the rear folding section 54 has a driving mechanism 544 that drives the air turn bars 541 and 542 in the rotation direction Ru. This driving mechanism 544 has an actuator 544a that moves a rod parallel to the horizontal direction X, and a connecting member 544b that connects the rod of the actuator 544a to an end face of the air turn bar 542 (the end face opposite to the end face to which the mounting member 543c is attached). Therefore, by driving the connecting member 544b with the actuator 544a, the air turn bars 541 and 542 can be rotated in the rotation direction Ru. Here, since the rotation angle of the air turn bars 541 and 542 is minute, the air turn bars 541 and 542 can be rotated by driving them in the horizontal direction X with the actuator 544a.

[0057] Furthermore, an edge sensor Su is provided between the air turn bars 541 and 542. This edge sensor Su is an optical sensor that detects the position of the edge in the horizontal direction Y of the printing medium M transported between the air turn bars 541 and 542. As will be described later, the rotation angle of the air turn bars 541 and 542 by the actuator 544a is feedback controlled based on the position of the edge of the printing medium M detected by the edge sensor Su.

[0058] FIG. 7 is a side view showing the configuration of the position adjustment unit, and FIG. 8 is a plan view showing the configuration of the position adjustment unit. The position adjustment unit 56 has the roller 561 as described above. The position adjustment unit 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, and 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 ends of the support member 561a are attached to the tip of the rotation shaft 563a. Therefore, the roller 561 can rotate in a rotation direction Rd centered on a straight line parallel to the vertical direction Z along with the rotation shaft 563a.

[0059] Furthermore, the position adjustment unit 56 has a driving mechanism 564 that drives the roller 561 in the rotation direction Rd. This driving 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 an end of the support member 561a (the end opposite to the end face to which the rotation shaft 563a is attached). Therefore, by driving the support member 561a with the actuator 564a, it is possible to rotate the roller 561 in the rotation direction Rd. Here, since the rotation angle of the roller 561 is minute, it is possible to rotate the roller 561 by driving it in the horizontal direction X with the actuator 564a.

[0060] Further, an edge sensor Sd is provided downstream of the roller 561 in the transport direction of the printing medium M. This edge sensor Sd is an optical sensor that detects the position of the edge in the horizontal direction Y of the printing medium M transported 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 printing medium M detected by the edge sensor Sd.

[0061] 7, the position adjustment unit 56 has a roller 568 between the winding roll 12 and the roller 561, and the roller 568 supports the printing medium M between the roller 561 and the winding roll 12. In other words, the printing medium M is taken up onto the winding roll 12 from the roller 561 via the roller 568. The edge sensor Sd detects the position of the edge of the printing medium M transported between the roller 561 and the roller 568.

[0062] FIG. 9 is a block diagram showing an electrical configuration of the drying device according to the first embodiment. As shown in the figure, the drying device 5 includes a control unit 100, which is a processor such as a CPU (Central Processing Unit), and a storage unit 110, which is a storage device such as a HDD (Hard Disk Drive). The storage unit 110 stores target positions Ptu and Ptd of the printing medium M in the horizontal direction Y (in other words, the width direction of the printing medium M). Here, the target position Ptu is the target position of the edge position of the printing medium M detected by the edge sensor Su, and the target position Ptd is the target position of the edge position of the printing medium M detected by the edge sensor Sd. Then, the control unit 100 executes feedback control for each of the air turn bars 541 and 542 and the roller 561 based on the target positions Ptu and Ptd.

[0063] For example, the target position Ptu is set so that a center line parallel to the horizontal direction X that passes through the center of each of the air turn bars 541, 542 in the horizontal direction Y coincides with the center of the print medium M in the horizontal direction Y. Moreover, the target position Ptd is set so that a center line parallel to the horizontal direction X that passes through the center of the roller 561 in the horizontal direction Y coincides with the center of the print medium M in the horizontal direction Y. However, the specific setting values ​​of the target positions Ptu, Ptd are not limited to this example.

[0064] The control unit 100 inputs an operation amount corresponding to the difference between the position of the edge of the printing medium M detected by the edge sensor Su and the target position Ptu to the actuator 544a. The actuator 544a rotates the air turn bars 541, 542 in the rotation direction Ru by a rotation angle θu (amount of displacement) corresponding to the operation amount. This executes feedback control so as to reduce the difference between the position of the edge of the printing medium M detected by the edge sensor Su and the target position Ptu. As a result, the position of the edge of the printing medium M detected by the edge sensor Su can be kept within a predetermined range (in other words, the range of steady-state deviation) from the target position Ptu.

[0065] Furthermore, the control unit 100 inputs an operation amount corresponding to the difference between the position of the edge of the printing medium M detected by the edge sensor Sd and the target position Ptd to the actuator 564a. The actuator 564a rotates the roller 561 in the rotation direction Rd by a rotation angle θd (amount of displacement) corresponding to the operation amount. This executes feedback control so as to reduce the difference between the position of the edge of the printing medium M detected by the edge sensor Sd and the target position Ptd. As a result, the position of the edge of the printing medium M detected by the edge sensor Sd can be kept within a predetermined range (in other words, the range of steady-state deviation) from the target position Ptd.

[0066] There are various ways to determine the rotation angles θu and θd. For example, the rotation angle θu may be set to zero degrees when the air turn bars 541 and 542 are parallel to the horizontal direction Y, and the clockwise direction may be set to the positive side of the rotation angle θu in a plan view, and the counterclockwise direction may be set to the negative side of the rotation angle θu. Similarly, the rotation angle θd may be set to zero degrees when the roller 561 is parallel to the horizontal direction Y, and the clockwise direction may be set to the positive side of the rotation angle θd in a plan view, and the counterclockwise direction may be set to the negative side of the rotation angle θd.

[0067] In this manner, in the above embodiment, the print medium M is transported by floating transport in a long section in which the print medium M is transported from the roller 522 (pre-rotating body) to the other side X2, then turned back to the one side X1 by the air turn bars 541 and 542 (non-contact support members), and then transported to the roller 561 (post-rotating body). Therefore, the position of the print medium M in the horizontal direction Y (width direction) is adjusted by rotating (displacing) the roller 561 according to the result of detecting the position of the print medium M in the horizontal direction Y (width direction) by the edge sensor Sd, thereby stabilizing the transport of the print medium M. However, if the transport of the print medium M is adjusted only by the rotation of the roller 561 over such a long floating transport section, the rotation angle required for the roller 561 becomes excessive, and it may be difficult to stabilize the transport of the print medium M. In contrast, in the above embodiment, the position of the printing medium M in the horizontal direction Y is adjusted by rotating the air turn bars 541, 542 that turn the printing medium M between the roller 522 and the roller 561. This makes it possible to reduce the rotation angle required for the roller 561. As a result, it is possible to stably transport the printing medium M in the floating transport section from the roller 522 to the roller 561.

[0068] Also, an edge sensor Su is provided to detect the position of the edge of the print medium M in the horizontal direction Y. In the direction in which the print medium M is transported, the edge sensor Sd (first position sensor) detects the position of the print medium M downstream of the rear folding unit 54, and the edge sensor Su (second position sensor) detects the position of the print medium M upstream of the edge sensor Sd. The rear folding unit 54 adjusts the position of the print medium M in the horizontal direction Y by displacing the air turn bars 541 and 542 by the actuator 544a (support member driving unit) according to the position of the print medium M detected by the edge sensor Su. In this configuration, the air turn bars 541 and 542 are rotated based on the position of the print medium M detected by the edge sensor Su to optimize the transport position of the print medium M, while the roller 561 is rotated based on the position of the print medium M detected by the edge sensor Sd to optimize the transport position of the print medium M. Therefore, the print medium M can be stably transported in the floating transport section from the roller 522 to the roller 561.

[0069] Further, in the rear folding section 54, an air turn bar 541 (upper non-contact support member) and an air turn bar 542 (lower non-contact support member) are provided, and the print medium M is folded downward by the air turn bar 541, and then folded back to one side X1 by the air turn bar 542. In response to this, the edge sensor Su detects the position of the print medium M between the air turn bars 541 and 542. In this configuration, the position of the print medium M detected by the edge sensor Su can be accurately adjusted by the rotation angles of the air turn bars 541, 542.

[0070] As can be seen from FIG. 2 and FIG. 7, the distance between the edge sensor Sd and the roller 561 along the printing medium M is shorter than the distance between the edge sensor Sd and the rear-stage folding unit 54 along the printing medium M. Here, the distance between the edge sensor Sd and the roller 561 is the distance between the range where the edge sensor Sd detects the printing medium M and the range where the roller 561 wraps the printing medium M, and the distance between the edge sensor Sd and the rear-stage folding unit 54 is the distance between the range where the edge sensor Sd detects the printing medium M and the range where the air turn bar 542 wraps the printing medium M (in other words, the circumferential surface 542a of the air turn bar 542). In this configuration, the edge sensor Sd is disposed close to the roller 561. Therefore, the position of the printing medium M detected by the edge sensor Sd can be accurately adjusted by the rotation angle of the roller 561. As a result, the position of the printing medium M can be optimized over the entire floating transport section from the roller 522 to the roller 561.

[0071] Furthermore, the edge sensor Sd detects the position of the printing medium M downstream of the roller 561 in the direction in which the printing medium M is transported. In this configuration, the displacement amount of the roller 561 is adjusted based on the position of the printing medium M detected by the edge sensor Sd provided after the floating transport section from the roller 522 to the roller 561. As a result, the position of the printing medium M can be optimized over the entire floating transport section from the roller 522 to the roller 561.

[0072] Next, a modified example of the above embodiment will be described. Note that the description will focus on the differences from the above embodiment, and the same reference numerals will be used to denote the common parts with the above embodiment, and the description will be omitted as appropriate.

[0073] Fig. 10 is a diagram showing, in table form, target position control information used in the drying device according to the second embodiment. As in the first embodiment, the drying device 5 according to the second embodiment also executes feedback control using the electrical configuration shown in the block diagram of Fig. 9. However, in the second embodiment, the storage unit 110 stores target position control information Ip in Fig. 10 instead of the target position Ptu. This target position control information Ip indicates the rotation angle θd of the roller 561 and the target position Ptu when feedback controlling the air turn bars 541 and 542 in association with each other.

[0074] That is, the control unit 100 performs feedback control on the position of the printing medium M by operating the actuator 564a based on a comparison between the position of the edge of the printing medium M detected by the edge sensor Sd and the target position Ptd. For example, the target position Ptd is set so that a center line parallel to the horizontal direction X passing through the center of the roller 561 in the horizontal direction Y coincides with the center of the printing medium M in the horizontal direction Y. The control unit 100 calculates the rotation angle θd of the roller 561 for which feedback control has been performed based on, for example, the amount of operation of the actuator 564a, and obtains a target position Ptu associated with the rotation angle θd using the target position control information Ip. Then, the control unit 100 performs feedback control on the rotation angle θu of the air turn bars 541 and 542 based on a comparison between the target position Ptu obtained using the target position control information Ip and the position of the printing medium M detected by the edge sensor Su.

[0075] In this way, in the second embodiment, the target position Ptu in the feedback control for the position of the printing medium M supported by the air turn bars 541, 542 is set according to the rotation angle θd of the roller 561 rotated by the actuator 564a (rotating body driving unit). In other words, the target position Ptu (target value) in the feedback control for rotating the air turn bars 541, 542 based on the position of the printing medium M detected by the edge sensor Su is set according to the rotation angle θd of the roller 561. Therefore, it is possible to execute control such as suppressing the rotation angle θd of the roller 561 by shifting the target position Ptu in the feedback control in the rotation direction (clockwise / counterclockwise) of the roller 561. Therefore, it is possible to stably transport the printing medium M in the floating transport section from the roller 522 to the roller 561.

[0076] The relationship between the rotation angle θd in the target position control information Ip and the target position Ptu may be determined based on a previously conducted experiment or a theoretical model. In short, the target position Ptu may be determined so as to assist in adjusting the position of the print medium M by the rotation angle θd of the roller 561 (in other words, so as to suppress the rotation angle θd required of the roller 561).

[0077] 11 is a block diagram showing an electrical configuration of a drying device according to the third embodiment. In the third embodiment, unlike the first embodiment, feedback control to the air turn bars 541, 542 is not performed based on the detection result of the edge sensor Su, and the edge sensor Su is not required. Instead, the rotation angle θu of the air turn bars 541, 542 is determined based on the rotation angle θd of the roller 561. Specifically, the storage unit 110 stores rotation angle information Ir indicating the correspondence between the rotation angle θd and the rotation angle θu instead of the target position Ptu.

[0078] Fig. 12 is a diagram that shows rotation angle information used in the third embodiment in the form of a table, and Fig. 13 is a flowchart showing an example of a method for acquiring the rotation angle information of Fig. 12. That is, before the transport of the print medium M begins for drying by the drying device 5, the control unit 100 executes the flowchart of Fig. 13 to experimentally obtain the rotation angle information Ir in advance. Note that, while the edge sensor Su is attached to the drying device 5 when the flowchart of Fig. 13 is executed, the edge sensor Su is removed from the drying device 5 after the flowchart is completed.

[0079] In step S101, the rotation angle θd of the roller 561 is reset. As a result, the rotation angle θd is set to, for example, zero degrees. In step S102, the rotation angle θd of the roller 561 is changed by a small angle. In this state in which the rotation angle θd of the roller 561 is changed, the control unit 100 executes feedback control on the rotation angle θu of the air turn bars (ATB) 541, 542 in the manner described using the block diagram of FIG. 9 (step S103). Then, the control unit 100 records the rotation angle θu of the air turn bars 541, 542 adjusted by the feedback control in step S103 and the rotation angle θd of the roller 561 set in step S102 in association with each other.

[0080] In step S105, it is determined whether the correspondence between the rotation angle θd and the rotation angle θu has been acquired for the entire movable range of the rotation angle θd of the roller 561. The movable range of the rotation angle θd can be set on both the positive and negative sides with zero degrees as the center. Then, when acquisition of the entire movable range is completed, the flowchart in FIG. 13 ends, and the rotation angle information Ir in FIG. 12 is completed.

[0081] When the drying device 5 dries the print medium M, the control unit 100 performs feedback control on the position of the print medium M by operating the actuator 564a based on a comparison between the position of the edge of the print medium M detected by the edge sensor Sd and the target position Ptd in the same manner as in the first and second embodiments described above. The control unit 100 also calculates the rotation angle θd of the roller 561 for which feedback control has been performed based on, for example, the amount of operation of the actuator 564a, and obtains the rotation angle θu associated with the rotation angle θd using the rotation angle information Ir. The control unit 100 then controls the actuator 544a to rotate the air turn bars 541 and 542 by the rotation angle θu obtained using the rotation angle information Ir.

[0082] Thus, in the third embodiment, the rotation angle information Ir (displacement amount information) indicating the correspondence between the rotation angle θd (rotating body displacement amount) of the roller 561 and the rotation angle θu (support member displacement amount) of the air turn bars 541 and 542 required when the roller 561 rotates by the rotation angle θd is stored in the storage unit 110. Then, the rear stage folding unit 54 rotates the air turn bars 541 and 542 by the rotation angle θu associated by the rotation angle information Ir with respect to the rotation angle θd of the roller 561 rotated by the actuator 564a (rotating body driving unit). In this configuration, the rotation angle θd of the roller 561 is adjusted according to the position of the printing medium M detected by the edge sensor Sd, and the rotation angle θu of the air turn bars 541 and 542 is adjusted according to the rotation angle θd of the roller 561. Therefore, there is no need to provide an edge sensor separately from the edge sensor Sd to adjust the rotation angle θu of the air turn bars 541 and 542. Therefore, the configuration can be simplified and costs can be reduced.

[0083] 12 associates the rotation angle θd of the roller 561 with the rotation angle θu of the air turn bars 541 and 542. However, the rotation angle information Ir may be configured to indicate the position of the edge of the print medium M detected by the edge sensor Sd in association with the rotation angle θu of the air turn bars 541 and 542 (fourth embodiment). In this case, in the flowchart of FIG. 13, the detection position of the edge sensor Sd when the rotation angle θd of the roller 561 is changed is confirmed (step S102), and the detection position of this edge sensor Sd and the rotation angle θu of the air turn bars 541 and 542 are associated and recorded (step S104).

[0084] That is, in the fourth embodiment, the rotation angle information Ir (displacement amount information) indicating the correspondence between the detection position by the edge sensor Sd and the rotation angle θu (support member displacement amount) of the air turn bars 541 and 542 required when the edge sensor Sd indicates the detection position is stored in the storage unit 110. Then, the rear stage folding unit 54 rotates the air turn bars 541 and 542 by the rotation angle θu associated with the rotation angle information Ir with respect to the detection position indicated by the edge sensor Sd using the actuator 544a. In this configuration, the rotation angle θd of the roller 561 is adjusted according to the position of the printing medium M detected by the edge sensor Sd, and the rotation angle θu of the air turn bars 541 and 542 is also adjusted according to the position of the printing medium M detected by the edge sensor Sd. Therefore, there is no need to provide an edge sensor separately from the edge sensor Sd to adjust the rotation angle θu of the air turn bars 541 and 542. Therefore, the configuration can be simplified and the cost can be reduced.

[0085] Incidentally, the transport state of the printing medium M is affected by the type of the printing medium M. In other words, depending on the type of the printing medium M, the printing medium M may be more likely to meander. Here, the type of the printing medium M is distinguished by the material, thickness, or width of the printing medium M. Therefore, as shown in FIG. 14, the rotation angle information Ir may be configured to indicate the type of the printing medium M in association with the rotation angle θu of the air turn bars 541, 542 (fifth embodiment). Here, FIG. 14 is a diagram showing the rotation angle information used in the fifth embodiment in a table format.

[0086] In the fifth embodiment, before the transportation of the printing medium M is started to dry the printing medium M, the control unit 100 confirms the type of the printing medium M. The type of the printing medium M is set in advance in the storage unit 110 by, for example, an operator. The control unit 100 also obtains a rotation angle θu associated with the confirmed type of the printing medium M by the rotation angle information Ir. Then, the control unit 100 rotates the air turn bars 541 and 542 by the rotation angle θu obtained by the rotation angle information Ir.

[0087] That is, in the fifth embodiment, the rotation angle information Ir (displacement amount information) indicating the correspondence between the type of the print medium M and the rotation angle θu of the air turn bars 541, 542 required for transporting the print medium M of that type is stored in the storage unit 110. Then, the rear stage folding unit 54 rotates the air turn bars 541, 542 by the rotation angle θu associated with the rotation angle information Ir for the type of the print medium M to be transported, using the actuator 544a. In this configuration, the position of the print medium M in the horizontal direction Y is adjusted by rotating the air turn bars 541, 542 according to the type of the print medium M. This makes it possible to suppress the rotation angle θd required for the roller 561. As a result, it is possible to stably transport the print medium M in the floating transport section from the roller 522 to the roller 561.

[0088] 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, the drying device 5 corresponds to an example of the "drying device" of the present invention, the front-stage folding section 52 corresponds to an example of the "front-stage folding section" of the present invention, each of the rollers 521 and 522 corresponds to an example of the "front-stage rotating body" of the present invention, the rear-stage folding section 54 corresponds to an example of the "rear-stage folding section" of the present invention, the air turn bars 541 and 542 correspond to an example of the "non-contact support member" of the present invention, and the air turn bar 541 corresponds to an example of the "upper non-contact support member" of the present invention. ", air turn bar 542 corresponds to an example of a "lower non-contact support member" of the present invention, actuator 544a corresponds to an example of a "support member drive unit" of the present invention, roller 561 corresponds to an example of a "rear stage rotating body" of the present invention, actuator 564a corresponds to an example of a "rotating body drive unit" of the present invention, upper stage conveying unit 51u corresponds to an example of an "upper stage conveying unit" of the present invention, middle stage conveying unit 51m corresponds to an example of a "middle stage conveying unit" of the present invention, lower stage conveying unit 51l corresponds to an example of a "lower stage conveying unit" of the present invention, and nozzle 76u of upper stage conveying unit 51u corresponds to an "upper stage printing surface nozzle" of the present invention. the nozzle 76l of the middle transport section 51m corresponds to an example of a "middle printed surface nozzle" of the present invention, the nozzle 76u of the middle transport section 51m corresponds to an example of a "middle non-printed surface nozzle" of the present invention, the nozzle 76u of the lower transport section 51l corresponds to an example of a "lower printed surface nozzle" of the present invention, the nozzle 76l of the lower transport section 51l corresponds to an example of a "lower non-printed surface nozzle" of the present invention, the control section 100 corresponds to an example of a "position adjustment section" of the present invention, the memory section 110 corresponds to an example of a "memory section" of the present invention, the rotation angle information Ir corresponds to an example of "displacement amount information" of the present invention, and the printing medium M corresponds to an example of a "position adjustment section" of the present invention. In the present invention, the surface M1 corresponds to an example of a "printing medium", the surface M1 corresponds to an example of a "printing surface", the back surface M2 corresponds to an example of a "non-printing surface", the edge sensor Sd corresponds to an example of a "first position sensor" and the edge sensor Su corresponds to an example of a "second position sensor" of the present invention, the horizontal direction X corresponds to an example of a "horizontal direction" of the present invention, one side X1 corresponds to an example of a "one side" of the present invention, the other side X2 corresponds to an example of a "other side" of the present invention, the rotation angle θd corresponds to an example of a "rotating body displacement amount" of the present invention, and the rotation angle θu corresponds to an example of a "support member displacement amount" of the present invention.

[0089] The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the front folding section 52 does not necessarily have to be composed of two rollers 521, 522, and may be configured to fold the print medium M from one side X1 to the other side X2 by one large roller. Similarly, the rear folding section 54 does not necessarily have to be composed of two air turn bars 541, 542.

[0090] Furthermore, the configuration of the rotation support mechanism 543 that displaces the air turn bars 541 and 542 is not limited to the above example. That is, the rotation support mechanism 543 may be configured so as to displace the air turn bars 541 and 542 by a motor instead of an actuator. The same applies to the rotation support mechanism 563 that displaces the roller 561.

[0091] The positions of the rotation centers of the air turn bars 541 and 542 and the roller 561 are not limited to the above examples and can be changed as appropriate. The displacement direction of the roller 561 is not limited to the rotation direction Rd and may be the horizontal direction Y.

[0092] Moreover, the position of the edge sensor Sd or the edge sensor Su can also be changed as appropriate.

[0093] 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 performed, for example, by the configuration shown in FIG. 15. FIG. 15 is a block diagram showing a configuration for controlling the injection amount and the exhaust amount. The blower chambers 72u and 72l of the blower dryers 7a to 7e are provided with blower pumps Ps, and hot air generated by heating the outside air with the main heater Hm is supplied to the blower chambers 72u and 72l by the blower pumps Ps and is ejected from the nozzles 76u and 76l. The exhaust units 8a and 8b are provided with exhaust pumps Pe, and the exhaust units 8a and 8b exhaust air from the inside of the housing 6 in response to the operation of the exhaust pump Pe. The control unit 100 controls the blower pumps Ps and the exhaust pumps Pe to adjust the injection amount and the exhaust amount as described above. As a result, the exhaust amount increases in response to an increase in the injection amount, while the exhaust amount decreases in response to a decrease in the injection amount. [Industrial Applicability]

[0094] The present invention is applicable to all techniques for drying a print medium having ink attached thereto by jetting gas. [Explanation of symbols]

[0095] 1. Printing system 3...Printing device 5...Drying device 52…Front folded section 521...Roller (pre-rotating body) 522...Roller (pre-rotating body) 54…Rear folded section 541...Air turn bar (non-contact support member, upper non-contact support member) 542...Air turn bar (non-contact support member, lower non-contact support member) 544a...actuator (support member driving unit) 561...Roller (rear rotating body) 564a...Actuator (rotating body drive unit) 51u…Upper conveyor section 51m…Middle conveyor section 51l…Lower conveying section 76u…Nozzle 76l…Nozzle 100...Control unit (position adjustment unit) 110...Storage section Ir...Rotation angle information (displacement amount information) M…Print media M1…Surface (printed surface) M2…Back side (non-printing side) Sd...Edge sensor (first position sensor) Su...Edge sensor (second position sensor) X…Horizontal direction X1…One side X2: Other side θd…Rotation angle (displacement of rotating body) θu…Rotation angle (displacement of support member)

Claims

1. an upper conveying section that conveys a long strip of print medium having a print surface with ink attached thereto and a non-print surface opposite to the print surface, to one side in a horizontal direction with the print surface facing upward; a front-stage folding section that has a front-stage rotating body that rotates while contacting the non-printing surface of the print medium, and that folds the print medium transported from the upper-stage transport section downward by the front-stage rotating body and then folds it back to the other side opposite to the one side; a middle stage conveying section that conveys the print medium folded back to the other side by the front stage folding section, with the print surface facing downward, to the other side; a rear-stage folding section having a non-contact support member that supports the print medium by injecting gas onto the printing surface of the print medium, the rear-stage folding section folding the print medium conveyed from the middle-stage conveying section downward by the non-contact support member and then folding it back to the one side; a lower stage conveying section that conveys the print medium folded back to the one side by the rear stage folding section, with the print surface facing upward; a first position sensor for detecting a position in a width direction of the print medium; a position adjustment unit including a rear-stage rotating body that rotates while contacting the print medium transported from the lower transport unit, and a rotating body drive unit that drives the rear-stage rotating body, and adjusts the position of the print medium in the width direction by displacing the rear-stage rotating body using the rotating body drive unit in accordance with the position of the print medium detected by the first position sensor; Equipped with the upper conveying unit has a plurality of upper printing surface nozzles arranged above the print medium, and ejects gas onto the print surface from the upper printing surface nozzles; the middle stage transport unit has a plurality of middle stage printed surface nozzles arranged below the print medium and a plurality of middle stage non-printed surface nozzles arranged above the print medium, and transports the print medium without contacting the print medium by ejecting gas from the middle stage printed surface nozzles onto the print surface of the print medium and ejecting gas from the middle stage non-printed surface nozzles onto the non-printed surface; the lower stage transport unit has a plurality of lower stage printing surface nozzles arranged above the printing medium and a plurality of lower stage non-printing surface nozzles arranged below the printing medium, and transports the printing medium without contacting the printing medium by ejecting gas from the lower stage printing surface nozzles onto the printing surface of the printing medium and ejecting gas from the lower stage non-printing surface nozzles onto the non-printing surface; the rear folding section further includes a support member drive section that displaces the non-contact support member, and the support member drive section displaces the non-contact support member to adjust a position of the print medium in a width direction; The first position sensor detects the position of the print medium downstream of the rear folding unit in a direction in which the print medium is transported.

2. a second position sensor for detecting a position in a width direction of the print medium; In a direction in which the print medium is transported, the first position sensor detects a position of the print medium downstream of the rear folding section, and the second position sensor detects a position of the print medium upstream of the first position sensor, The drying device according to claim 1 , wherein the rear folding section adjusts the widthwise position of the printing medium by displacing the non-contact support member using the support member driving section in accordance with the position of the printing medium detected by the second position sensor.

3. The drying device described in claim 2, wherein the rear-stage turning unit performs feedback control to displace the non-contact support member using the support member driving unit so as to reduce the difference between the position of the printing medium detected by the second position sensor and a target position of the printing medium, and the target position in the feedback control is set according to the amount of displacement of the rear-stage rotating body displaced by the rotating body driving unit.

4. In the rear folding section, an upper non-contact support member and a lower non-contact support member arranged below the upper non-contact support member are provided as the non-contact support members, and the print medium is folded downward by the upper non-contact support member, and then folded back to the one side by the lower non-contact support member; 4. The drying device according to claim 2, wherein the second position sensor detects the position of the print medium between the upper non-contact support member and the lower non-contact support member.

5. a storage unit configured to store displacement amount information indicating a correspondence relationship between a rotor displacement amount, which is a displacement amount of the rear rotor, and a support member displacement amount, which is a displacement amount of the non-contact support member obtained when the rear rotor is displaced by the rotor displacement amount, The drying device according to claim 1 , wherein the rear-stage turning section displaces the non-contact support member by the support member driving section by the support member displacement amount associated with the displacement amount information, relative to the rotor displacement amount of the rear-stage rotor displaced by the rotor driving section.

6. a storage unit configured to store displacement amount information indicating a correspondence relationship between a detected position by the first position sensor and a support member displacement amount, which is a displacement amount of the non-contact support member obtained when the first position sensor indicates the detected position; The drying device according to claim 1 , wherein the rear turning section displaces the non-contact support member by the support member driving section by the support member displacement amount associated with the displacement amount information relative to the detection position indicated by the first position sensor.

7. The drying device according to claim 5 or 6, wherein a distance between the first position sensor and the rear rotating body along the printing medium is shorter than a distance between the first position sensor and the rear folding portion along the printing medium.

8. 8. The drying device according to claim 1, wherein the first position sensor detects the position of the print medium downstream of the rear rotating body in a direction in which the print medium is transported.

9. a storage unit that stores displacement amount information indicating a correspondence relationship between a type of the print medium and a displacement amount of the non-contact support member required for transporting the print medium of the type; The drying device according to claim 1 , wherein the rear-stage folding section displaces the non-contact support member by the support member driving section by an amount of displacement associated with the type of the transported print medium by the displacement amount information.

10. a printing device that prints an image by ejecting ink onto the printing surface of the printing medium; The drying device according to any one of claims 1 to 9, which dries the ink discharged by the printing device and adhering to the printing surface. A printing system comprising:

11. a step of conveying a long strip-shaped print medium having a print surface with ink attached thereto and a non-print surface opposite to the print surface to one side in a horizontal direction with the print surface facing upward, while ejecting gas onto the print surface from a plurality of upper print surface nozzles arranged above the print medium; a step of folding the print medium conveyed to the one side downward by a front-stage rotating body that rotates while contacting the non-printing surface of the print medium, and then folding the print medium back to the other side opposite to the one side; a step of transporting the print medium that has been folded back to the other side with the print surface facing downward, and supporting the print medium without contacting the print medium by spraying gas onto the print surface of the print medium from a plurality of middle stage print surface nozzles arranged below the print medium and spraying gas onto the non-print surface from a plurality of middle stage non-print surface nozzles arranged above the print medium; 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 the print medium back to the one side; a step of transporting the print medium folded back to the one side with the print surface facing upward, and supporting the print medium without contacting the print medium by spraying gas onto the print surface of the print medium from a plurality of lower print surface nozzles arranged above the print medium and spraying gas onto the non-print surface from a plurality of lower non-print surface nozzles arranged below the print medium; transporting the print medium transported to the one side by a rear-stage rotating body that rotates while in contact with the print medium; Equipped with a position of the print medium in the width direction is adjusted by displacing the non-contact support member, and a position of the print medium in the width direction is adjusted by displacing the rear rotating body in accordance with a result of detecting the position of the print medium in the width direction; The drying method includes detecting the position of the print medium in the width direction downstream of the non-contact support member in the direction in which the print medium is transported.

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