JP2021059414A - Sheet correction device, printer, and printing system - Google Patents

Abstract

To suppress the occurrence of image flaws when performing correction while holding with a belt pair.SOLUTION: A sheet correction device comprises: a pair of belts 611A, 611B which conveys a sheet P applied with liquid by holding the sheet therebetween; a plurality of rollers 603 which give the curvature to a belt pair 602; a heater 604 which heats the sheet P through at least one belt of the belt pair 602; belt position detection means 670 which detects the width direction position of each belt 611; and a meander correction mechanism 660 which corrects the meander of each belt 611 on the basis of the detection result of the belt position detection means 670. The belt 611 can move in the width direction along a peripheral face of the roller 603 in a state of being in contact with the roller 603. The belt 611 has a fluororesin layer on its surface. The sheet correction device performs control of correcting the meander of each belt 611 such that the sum of movement amounts in the width direction of each belt 611 falls within a predetermined specified value.SELECTED DRAWING: Figure 14

Description

The present invention relates to a sheet straightening device, a printing device, and a printing system.

When printing is performed by applying a liquid to a sheet such as paper, it is known to be provided with a sheet straightening device that suppresses cockling caused by the application of the liquid to the sheet.

Conventionally, as a sheet straightening device, a belt pair that sandwiches and conveys a sheet to which a liquid is applied, a plurality of curved members that give curvature to the belt pair, and a heating means that heats the sheet via at least one of the belt pairs. It is known that a belt pair is provided with a steering control roller that corrects the meandering of each belt (Patent Document 1).

JP-A-2019-119607

By the way, when the sheet is straightened while sandwiching the sheet between a pair of belts and heating the sheet, there is a problem that the liquid before fixing is rubbed by the belt due to the meandering of the belt and image scratches occur.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the occurrence of image scratches.

In order to solve the above problems, the sheet straightening device according to the present invention is
A pair of belts that sandwich and convey a sheet to which liquid is applied, and
A plurality of curved members that give curvature to the pair of belts,
A heating means for heating the sheet via at least one belt of the pair of belts,
A belt position detecting means for detecting the position in the width direction of each belt of the pair of belts,
A meandering correction means that corrects the meandering of each belt based on the detection result of the belt position detecting means, and
A means for controlling the meandering correction means and a means for controlling the meandering correction means are provided.
The pair of belts can move in the width direction of the belt along the curved surface of the curved surface member in a state of being in contact with the curved surface member.
At least one of the belts in contact with the liquid-coated surface of the sheet has a fluororesin layer on the surface.
The control means is configured to control the meandering of the belts so that the sum of the movement amounts of the belts in the width direction is within a predetermined value.

According to the present invention, the occurrence of image scratches can be suppressed.

It is a schematic explanatory drawing of the printing apparatus which concerns on 1st Embodiment of this invention. It is a side explanatory view of an example of the drying apparatus which comprises a drying part. It is a side explanatory view of an example of the sheet straightening apparatus which comprises the sheet straightening part. It is an enlarged side view explanatory view of the outlet side of the sheet straightening apparatus. It is a perspective explanatory view of an example of the meandering correction mechanism of an upper belt. It is explanatory drawing which provides the explanation of the belt position detecting means. It is a block explanatory view of the part which concerns the meandering correction control of a sheet straightening apparatus and the heating control of a drying apparatus. It is explanatory drawing of an example of the relationship between the inclination angle of the steering control roller and the moving speed in the width direction of a belt, which is used for the explanation of the meandering correction control of a belt by the meandering correction control means. It is explanatory drawing which provides the explanation of the sum of the belt movement amount in the width direction in meandering correction. It is explanatory drawing which provides the explanation of an example of the relationship between the residual solvent amount of a sheet, and the correction effect with respect to the deformation of a sheet. It is explanatory drawing which provides the explanation of an example of the relationship between the coating of a belt of a belt pair and the image scratch. It is explanatory drawing which provides the explanation of an example of the relationship between the coating of a belt pair, the amount of rubbing (rubbing amount), and image scratches. It is a flow figure which provides the explanation of the example of the heating control of a drying apparatus. It is a flow figure which provides the explanation of the meandering correction control in a sheet straightening apparatus. It is a side explanatory view of the sheet straightening apparatus which concerns on 2nd Embodiment of this invention. It is a flow figure which provides the explanation of the meandering correction control in the 2nd Embodiment. It is a flow figure which provides the explanation of the meandering correction control in 3rd Embodiment of this invention. It is a flow figure which provides the explanation of the meandering correction control in 4th Embodiment of this invention. It is a side explanatory view of the sheet straightening apparatus which concerns on 5th Embodiment of this invention. It is a side explanatory view of the sheet straightening apparatus which concerns on 6th Embodiment of this invention. It is a side explanatory view of the sheet straightening apparatus which concerns on 7th Embodiment of this invention. It is a side explanatory view of the sheet straightening apparatus which concerns on 8th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, an outline of the printing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic explanatory view of the printing apparatus.

The printing device 1 includes a carry-in section 100, a printing section 200, a drying section 300, a sheet straightening section 600, and a carry-out section 400. In the printing apparatus 1, the printing unit 200 applies a liquid to the sheet P carried in from the carrying-in unit 100 to perform the required printing, the drying unit 300 dries the liquid adhering to the sheet P, and then the sheet is straightened. The wavy deformation of the cock ring and the like generated in the seat P is corrected by the portion 600, and the seat P is discharged to the carry-out portion 400.

The carry-in unit 100 includes a carry-in tray 110 on which a plurality of sheets P are loaded, a feeding device 120 that separates and sends out the sheets P one by one from the carry-in tray 110, and a resist roller pair that feeds the sheets P to the printing unit 200. It is equipped with 130.

As the feeding device 120, any feeding device such as a device using rollers and rollers and a device using air suction can be used. The sheet P sent out from the carry-in tray 110 by the feeding device 120 is sent out to the printing unit 200 by driving the resist roller pair 130 at a predetermined timing after the tip of the sheet P reaches the resist roller pair 130.

The printing unit 200 includes a supported drum 210 that supports and conveys the sheet P on the outer peripheral surface, and a liquid discharge unit 220 that is a means for applying a liquid that discharges the liquid toward the sheet P supported on the supported drum 210. I have. Further, the printing unit 200 includes a delivery cylinder 201 that receives the fed sheet P and delivers it to the supporting drum 210, and a delivery cylinder 202 that delivers the sheet P conveyed by the supporting drum 210 to the drying unit 300.

The tip of the sheet P transported from the carry-in unit 100 to the printing unit 200 is gripped by a sheet gripper provided on the surface of the transfer cylinder 201, and is conveyed as the transfer cylinder 201 rotates. The sheet P conveyed by the transfer cylinder 201 is delivered to the supporting drum 210 at a position facing the supporting drum 210.

A sheet gripper is also provided on the surface of the supported drum 210, and the tip of the sheet P is gripped by the sheet gripper. A plurality of suction holes are dispersedly formed on the surface of the supported drum 210, and a suction device 211 generates a suction airflow toward the inside of the supported drum 210 in each suction hole.

The tip of the sheet P delivered from the transfer cylinder 201 to the carrier drum 210 is gripped by the sheet gripper, is adsorbed on the surface of the carrier drum 210 by the suction airflow, and is conveyed as the carrier drum 210 rotates. To.

The liquid discharge unit 220 is a liquid discharge means, which discharges four colors of liquid (ink) of C (cyan), M (magenta), Y (yellow), and K (black) to print an image. The liquid discharge heads 220C, 220M, 220Y, 220K are provided as means for applying individual liquids for each color of the liquid. If necessary, a liquid discharge head that discharges a special liquid such as white, gold, or silver, or a liquid discharge head that discharges a treatment liquid such as a surface coating liquid can be provided.

The discharge operation of each of the liquid discharge heads 220C, 220M, 220Y, 220K of the liquid discharge unit 220 is controlled by a drive signal corresponding to the print information. When the sheet P supported on the carrier drum 210 passes through the region facing the liquid discharge unit 220, liquids of each color are discharged from the liquid discharge heads 220C, 220M, 220Y, 220K, and an image corresponding to the print information is displayed. It will be printed.

The drying unit 300 includes a suction transfer mechanism unit 320 that sucks and conveys the sheet P conveyed from the printing unit 200, a drying mechanism unit 310 that dries the sheet P conveyed by the suction transfer mechanism 320, and the like. ing.

The sheet P conveyed from the printing unit 200 is received by the suction transfer mechanism unit 320, then conveyed so as to pass through the drying mechanism unit 310, delivered to the sheet straightening unit 600, and carried out from the sheet straightening unit 600. It is handed over to the part 400.

When passing through the drying mechanism unit 310, the liquid on the sheet P is subjected to a drying treatment. As a result, liquid components such as water in the liquid evaporate, and the colorant contained in the liquid is fixed on the sheet P.

When the sheet P after the drying process passes through the sheet straightening portion 600, deformation of the sheet P such as a cock ring is corrected.

The carry-out unit 400 includes a discharge tray 410 on which a plurality of sheets P are loaded. The sheets P conveyed from the sheet straightening section 600 are sequentially stacked and held on the discharge tray 410.

In the printing apparatus 1, for example, a pretreatment unit that performs pretreatment on the sheet P is arranged on the upstream side of the printing unit 200, or a post-processing unit that performs posttreatment on the sheet P to which the liquid is attached. Can be arranged between the sheet straightening section 600 and the carry-out section 400.

Examples of the pretreatment unit include those that perform a precoating treatment in which a treatment liquid for reacting with a liquid to suppress bleeding is applied to the sheet P. Further, as the post-processing unit, for example, a sheet reversal transfer process for reversing the sheet printed by the printing unit 200 and sending it to the printing unit 200 again for printing on both sides of the sheet P, or binding a plurality of sheets. Examples include those that perform processing.

In the printing apparatus 1, for example, a pretreatment section for pretreating the sheet material P is arranged on the upstream side of the printing section 200, or after the sheet material P to which the liquid is attached is post-treated. The processing unit may be arranged between the drying unit 300 and the carrying-out unit 400.

Examples of the pretreatment unit include those that perform a precoating treatment in which a treatment liquid for reacting with a liquid to suppress bleeding is applied to the sheet material P. Further, as the post-processing unit, for example, a sheet reversal transfer process for reversing the sheet printed by the printing unit 200 and sending it to the printing unit 200 again for printing on both sides of the sheet material P, or a plurality of sheets may be used. Examples include those that perform binding processing.

Further, the "printing apparatus" in the present application is not limited to an inkjet recording apparatus, and is provided with a liquid ejection head that ejects a liquid toward a sheet, and a significant image such as characters and figures is visualized by the ejected liquid. It is not limited, and includes, for example, a pattern that forms a pattern that has no meaning in itself.

Further, the "printing apparatus" can also include means related to feeding, transporting, and discharging paper to which a liquid can be attached, as well as a pretreatment apparatus and a posttreatment apparatus.

The "liquid" may have a viscosity and surface tension that can be discharged from the head, and is not particularly limited, but the "liquid" has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable to have. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions and the like containing edible materials such as natural pigments, etc., which can be used, for example, in inks for inkjets, surface treatment liquids and the like.

Further, the "printing device" includes a device in which the liquid discharge head and the sheet material move relative to each other, but the present invention is not limited to this. Specific examples include a serial type device that moves the liquid discharge head, a line type device that does not move the liquid discharge head, and the like.

The "liquid discharge head" is a functional component that discharges and ejects a liquid from a discharge hole (nozzle). As an energy generation source for discharging liquid, a piezoelectric actuator (laminated piezoelectric element or thin film piezoelectric element), a thermal actuator using an electrothermal conversion element such as a heat generating resistor, and an electrostatic actuator composed of a vibrating plate and a counter electrode are discharged. Although energy generating means can be used, the discharge energy generating means to be used is not limited.

Next, an example of a drying device constituting the drying portion will be described with reference to FIG. FIG. 2 is a side explanatory view of the drying device.

The drying device 301 includes a drying mechanism unit 310 which is a drying means and includes a heating means, and a suction transport mechanism unit 320 which is a transport means.

The drying mechanism unit 310 includes a blower unit 312 as a blower means and a radiant heater 313 such as an IR heater as a heating means in the internal space 311a of the chamber 311. The blower unit 312 blows air toward the sheet P conveyed by the suction transfer mechanism unit 320. The radiant heater 313 radiates radiant heat (for example, infrared rays) toward the sheet P conveyed by the suction transfer mechanism unit 320.

In the drying mechanism unit 310, the sheet material conveyed to the internal space 311a of the chamber 311 is applied to the sheet material P by the radiant heat of the radiant heater 313 and the ventilation (air blowing) by the ventilation unit 312. Allow the liquid to dry.

Here, a plurality of blower units 312 are arranged side by side in the transport direction of the sheet material P, but the number and arrangement of the blower units 312 are not limited to this. Further, although a plurality of radiant heaters 313 are arranged side by side in the transport direction of the sheet material P, the number and arrangement of the radiant heaters 313 are not limited to this.

The suction transfer mechanism unit 320 has a transfer belt 321 hung between the drive roller 322 and the driven roller 323, and the sheet P supported on the surface of the transfer belt 321 by the orbital movement of the transfer belt 321 is conveyed in the transfer direction. Transport in the Y (arrow direction).

The transport belt 321 has a plurality of minute through holes (suction holes), and the sheet P is attracted to the transport belt 321 by the suction mechanism 324 and transported. The transport belt 321 is arranged so that the upstream portion in the transport direction faces the delivery cylinder 25 of the printing unit 20. The sheet P conveyed by the transfer cylinder 25 is transferred to the transfer belt 321 and supported on the surface of the transfer belt 321.

Then, in the internal space 311a of the chamber 311 of the drying mechanism unit 310, a guard member 316 is arranged between the transport belt 321 constituting the transport surface, the blower unit 312, and the radiant heater 313. The guard member 316 prevents the sheet P from coming into contact with the radiant heater 313 or the like when the sheet P is lifted from the transport belt 321.

Next, an example of the sheet straightening device constituting the sheet straightening section will be described with reference to FIGS. 3 and 4. FIG. 3 is a side explanatory view of the sheet straightening device, and FIG. 4 is an enlarged explanatory view of the vicinity of the transport roller.

The sheet straightening device 601 is arranged on the downstream side of the drying device 301 in the sheet transport direction.

The sheet straightening device 601 includes a belt pair 602. The belt pair 602 is composed of a pair of belts 611 (upper belt 611A, lower belt 611B) that are conveyed across the seat P. The belt pair 602 constitutes a means for applying tension to the seat P.

In this embodiment, as the upper belt 611A and the lower belt 611B, a belt having a fluororesin layer on the surface is used. Here, PFA (perfluoroalkoxy alkane) is coated to form a fluororesin layer. The fluororesin layer may be a film containing both PFA and PTFE (polytetrafluoroethylene). Durability can be improved by including PTFE.

The upper belt 611A is hung around the transport roller 621A, the steering control roller 622A, the driven rollers 624A, and 625A, and tension is applied by the tension roller 623A.

The lower belt 611B is hung around the transport roller 621B, the steering control roller 622B, the driven rollers 624B, and 625B, and tension is applied by the tension roller 623B.

These upper belts 611A and lower belts 611B orbit in the direction of the arrow by rotationally driving the transport rollers 621A and 621B, sandwich the sheet P, and carry the seat P in the transport direction (arrow Y direction, hereinafter "convey direction". It is called "Y"). In the present embodiment, the rotary driving force is transmitted from the drive motor to the transfer roller 621B, and the drive force is transmitted from the transfer roller 621A to the transfer roller 621B via gears.

Further, as shown in FIG. 4, the transfer roller 621A and the transfer roller 621B are arranged apart from each other with a gap G10.

The area T for sandwiching and transporting the seat P between the upper belt 611A and the lower belt 611B is a region for sandwiching and transporting the seat P generated only by the upper belt 611A and the lower belt 611B, and the roller 603 holds the belt pair 602. It is composed of an area that sandwiches the sheet P by the sandwiching force generated by pushing.

At this time, no rotating body or the like is arranged on the opposite side of the roller 603 from the belt pair 602, and the upper belt 611A or the lower belt 611B on the side not in contact with the roller 603 is on the opposite side of the roller 603. Not in contact with the members of. Therefore, each belt 611 is in contact with the roller 603 which is a curved surface member, and is in the belt width direction (the width direction of the upper belt 611A and the lower belt 611B) along the peripheral surface (curved surface of the curved surface member) of the roller 603. It is possible to move to.

Here, the tension rollers 623A and 623B apply tension to the belts 611A and 612 of the belt pair 602 in a direction in which the belt surface sandwiching the seat P is pulled in the upstream side and the downstream side in the transport direction Y. It becomes a means to do.

Then, in the region T where the upper belts 611A and the lower belt 611B of the belt pair 602 face each other (face each other) and sandwich the seat P, they come into contact with the inner surface of the upper belt 611A or the lower belt 611B of the belt pair 602. It includes rollers 603 (603A, 603B) which are a plurality of (here, six) curved member members arranged along the transport direction Y. The roller 603 deforms a part of the belt pair 602 into a curved shape (curved deformation).

The roller 603 has a built-in heater 604 as a heat generating means, and is a heating roller that also serves as a heating means for heating a region of the sheet P that is pressed against the roller 603 via a belt pair 602 and is curved and deformed. ..

Here, the rollers 603A and the rollers 603B are alternately arranged with the roller 603B as the most upstream side in the region where the belt surfaces of the upper belt 611A and the lower belt 611B face each other (facing each other).

Then, the peripheral surface of the roller 603A is pressed against the upper belt 611A side of the belt pair 602 to bend and deform the belt pair 602 so as to have a convex shape downward. The peripheral surface of the roller 603B is pressed against the lower belt 611B side of the belt pair 602 to bend and deform the belt pair 602 so as to have an upward convex shape.

That is, in the transport direction of the sheet P, the roller 603A that bends and deforms in the direction in which one surface side of the sheet P becomes convex and the roller 603B that bends and deforms in the direction in which the other surface side of the sheet P becomes convex are alternately arranged. ing. It is also possible to arrange the rollers 603A and the rollers 603B alternately with the rollers 603A on the most upstream side.

The cock ring (deformation) straightening action of the seat straightening device 601 in the seat straightening section 600 will be described.

When the cock ring (wavy) remains on the seat P, if the seat P is wound while applying tension to a curved surface such as the peripheral surface of the roller 603, the wavy disappears while the seat P is wound. This is because the length of the sheet P of the portion to which the liquid is applied and the portion to which the liquid is not applied can be forcibly made the same length.

However, if the curved surface is simply wound while applying tension, the waviness returns to its original state and cannot be corrected when the tension is removed.

Therefore, by heating the sheet P with a heating means and squeezing it while removing the moisture in the sheet P, the length of the portion to which the liquid is applied and the portion to which the liquid is not applied can be made the same, and the cock ring of the sheet P can be made the same. It is possible to correct wavy deformation such as.

That is, as shown in FIG. 3, the seat P is sandwiched between the two upper belts 611A and the lower belt 611B, and in this state, the belt pair 602 is pressed against the peripheral surface of the roller 603, which is a heating roller. The belt pair 602 is deformed in a curved shape while sandwiching the seat P.

As a result, the sheet P is heated by the roller 603, and by imitating the peripheral surface of the roller 603, the lengths of the portion to which the liquid is applied and the portion to which the liquid is not applied become the same, and the cock ring of the sheet P or the like becomes the same. The wavy deformation of is corrected.

In this way, in a state where the sheet P is heated, the deformation of the sheet can be efficiently corrected by pressing the sheet P against a curved surface member (here, a roller) while applying tension to the sheet P to bend and deform the sheet P.

Then, as shown in FIG. 3, the upper belt 611A and the lower belt 611B come into contact with each other in the opposite region (the region T sandwiching the sheet P), and are heating rollers as a plurality of curved surface members along the transport direction P. Rollers 603 (603A, 603B) are arranged.

That is, as described above, by heating the sheet P with a heating means and squeezing it while removing the moisture in the sheet P, the length of the portion to which the liquid is applied and the portion to which the liquid is not applied can be made the same. It is possible to correct wavy deformation such as the cock ring of the seat P.

In this case, the correction effect is greater when the curved surface member (roller) is wound a plurality of times with a small winding angle than when the curved surface member (roller) is wound around the peripheral surface at a large winding angle.

For example, when the sheet P is wound around a roller of φ80 three times with a winding angle θ of 30 degrees, the case where the sheet P is wound three times with a winding angle θ of 90 degrees is more resistant to deformation of the sheet P. The correction effect is increased.

By arranging the plurality of curved surface members side by side in the transport direction in this way, it is possible to more efficiently correct the deformation of the sheet.

Further, in the present embodiment, the tension of the lower belt 611B is set to be equal to or less than the tension of the upper belt 611A.

That is, the seat P is sandwiched and conveyed between the upper belt 611A and the lower belt 611B, but since it is sandwiched, it is the lower belt 611B that gives the roller 603A a force to press the seat P, and the roller 603B is seated. It is the upper belt 611A that presses P.

Here, by weakening the tension of the lower belt 611B, the force with which the liquid-applied surface (image surface) touches the roller 603A is weakened, and the occurrence of image scratches can be reduced.

On the other hand, the upper belt 611A can prevent the straightening ability from being reduced by maintaining the required tension and surely pressing the upper belt 611A against the roller 603B.

Further, in the present embodiment, in the transport direction of the sheet P, the length of the circumferential region in which the sheet P follows the peripheral surface of the most upstream roller 603B (603Ba) is the circumferential direction in which the sheet follows the other rollers 603. The configuration is shorter than the length of the area. That is, the winding angle around the most upstream roller 603B (603Ba) is minimized.

As a result, the contact area at the most upstream roller 603B (603Ba) portion that the sheet P contacts immediately after passing through the drying portion 300 is reduced, and the amount of rubbing is reduced to suppress the occurrence of image scratches. be able to.

Further, in the transport direction of the sheet P, the most upstream roller 603B (603Ba) comes into contact with the lower belt 611B which is in contact with the surface of the belt pair 602 opposite to the liquid applying surface of the sheet P.

As a result, the higher the temperature, the more likely it is that image scratches will occur. Therefore, heating the most upstream side, where image scratches are most likely to occur, from the back surface has the effect of not raising the liquid temperature more than necessary, and suppresses the occurrence of image scratches. it can.

Further, by using the roller 603 as a driven roller, meandering is less likely to occur and the correction effect is improved.

Next, an example of the meandering correction means of the belt will be described with reference to FIGS. 5 and 6. FIG. 5 is a perspective explanatory view of an example of the meandering correction mechanism of the upper belt, and FIG. 6 is an explanatory view also used for explaining the belt position detecting means.

The meandering correction mechanism 660 constitutes a meandering correction means, and positions the steering control roller 622A, the motor 661, the arm 662 rotated by the motor 661, and the upper belt 611A in the width direction (direction orthogonal to the moving direction). It is provided with a belt position detecting means 670 for detecting the above.

Both ends of the steering control roller 622A are rotatably held by a roller holding member 666 which is rotatably held in the direction of arrow A via a support portion 665 which is a rotation center of the stay 664. One end of the steering control roller 622A is connected to one end of the arm 662, and the other end of the arm 662 is connected to the motor 661.

As a result, by rotationally driving the motor 661, the arm 662 can rotate in the direction of arrow B about the rotation center 662a, and the steering control roller 622A can tilt in the direction of arrow A around the support portion 665. Therefore, by controlling the rotation angle of the motor 661, the steering angle of the steering control roller 622A can be set to an arbitrary value.

As shown in FIG. 6, the belt position detecting means 670 includes a light receiving portion 671 in which two light receiving elements 671A and 671B are arranged, and a shielding plate 672 arranged so as to block the two light receiving elements 671A and 671B. ing.

The shielding plate 672 is rotatably arranged in the direction of arrow C about the rotation shaft 672a, and a pin member 674 that abuts on the widthwise end of the upper belt 611A is provided on one end side and faces the light receiving portion 671. A slit 673 is provided on the end side.

In the meandering correction means configured as described above, the meandering of the upper belt 611A causes the pin member 674 to be pushed at the end of the upper belt 611A, and the shielding plate 672 rotates about the rotation shaft 672a in the direction of arrow C. .. As a result, the positional relationship between the slit 673 of the shielding plate 672 and the light receiving elements 671A and 671B of the light receiving unit 671 changes.

At this time, the positional relationship between the slit 673 of the shielding plate 672 and the light receiving elements 671A and 671B is shown in FIG. 6, for example. FIG. 6A shows a case where the slit 673 is in a linear range facing the light receiving elements 671A and 671B. FIG. 6B shows a case where the slit 673 is in the saturation region facing only one of them (here, the light receiving element 671B). FIG. 6C shows a case where the slit 673 is in the error region facing only a part of one side (here, the light receiving element 671B).

The light receiving elements 671A and 671B output a voltage corresponding to the opening area (area facing the slit 673). Therefore, the current position of the upper belt 611A can be determined by looking at the outputs of the light receiving elements 671A and 671B.

Therefore, when it is determined from the result detected by the belt position detecting means 670 that the upper belt 611A deviates from the median value, the meandering can be corrected by steering the steering control roller 622A in the direction of moving in the opposite direction. ..

The same applies to the meandering correction mechanism of the lower belt 611B.

Next, the portion related to the meandering correction control of the sheet straightening device and the heating control of the drying device will be described with reference to the block explanatory view of FIG. 7.

The meandering correction control means 801 controls the drive of the motor 661 of the meandering correction mechanism 660 based on the detection result of the belt position detecting means 670 to correct the meandering of the upper belt 611A and the lower belt 611B. At this time, the meandering correction control means 801 has a movement speed in the width direction of the upper belt 611A and the lower belt 611B (the total amount of leaning when the belt is conveyed per unit length (total amount of movement L3)) within the specified value. Control so that it fits in.

Information correlating with the thickness of the sheet P is input from the operation unit 802 to the meandering correction control means 801. Here, information indicating the type of the sheet P is input.

The storage means 803 stores the relationship between the type and thickness of the sheet P, a specified value when meandering correction is performed on the thickness of the sheet P, and the like.

Then, the meandering correction control means 801 determines the thickness of the sheet P from the type information of the sheet P input from the operation unit 802, reads out the specified value corresponding to the thickness of the sheet P, and belts within the specified value. The rotation angle of the motor 661 is controlled so that the moving speed in the width direction is within the range.

The drying control means 811 is a means for controlling ON / OFF of the radiant heater 313 of the drying device 301, which is a drying means, and the heat generation temperature (heating temperature).

Information correlating with the thickness of the sheet P is input from the operation unit 802 to the drying control means 811. Here, information indicating the type of the sheet P is input.

Information such as the relationship between the type and thickness of the sheet P and the relationship between the thickness of the sheet P and the heating temperature of the drying device 301 is stored in the storage means 803.

Then, the drying control means 811 determines the thickness of the sheet P from the type information of the sheet P input from the operation unit 802, and controls the heat generation temperature (heating temperature) of the radiant heater 313 by the thickness of the sheet P. , The degree of drying of the sheet P is changed.

Next, the meandering correction control of the belt 611 by the meandering correction control means will be described with reference to FIGS. 8 and 9. FIG. 8 is an explanatory diagram of an example of the relationship between the tilt angle of the steering control roller and the moving speed of the belt in the width direction, and FIG. 9 is an explanatory diagram provided for explaining the sum of the belt movement amounts in the width direction in the meandering correction.

The meandering correction control means 801 performs a homing operation of the roller position of the steering control roller 622. In this homing operation, the motor 661 of the meandering correction mechanism 660 is rotated in one direction to detect the home position, so that the position of the steering control roller 622 is always moved to the home position position.

Next, the meandering correction control means 801 initializes the position of the belt 611. In this initialization operation, the belts 611 are driven for a specified time (short time), and the total amount of deviations (L1 + L2) from the target median value of each belt 611 is within the specified value (for example, within 0 ± 100 μm: deviation in FIG. 9). If the total amount is L3), the ready state is set.

After that, the meandering correction control means 801 starts driving the belt 611 and the meandering correction control at the same time as the printing starts.

In this meandering correction control, the current position of the belt 611 is acquired from the output values of the light receiving elements 671A and 671B of the light receiving unit 671 of the belt position detecting means 670. For example, the one-round average of the belt 611 is acquired as the current position, and as shown in FIG. 8, for example, from the relationship between the roller angle acquired in advance and the moving speed in the width direction (indicated as “belt-approaching speed” in FIG. 8), The steering control roller 622 is controlled to be tilted so as to keep the moving speed in the width direction within the specified value.

Here, in the present embodiment, with reference to FIG. 9, the sum of the belt movement amounts in the relative width direction of the upper belt 611A and the lower belt 611B is controlled to be within the specified value. The sum L3 of the belt movement amount in the width direction is the movement amount when the upper belt 611A and the lower belt 611B move in opposite directions with respect to the reference position (FIG. 9A) of the upper belt 611A and the lower belt 611B. Is the sum of (L3 = L1 + L2), which is an amount that does not cause image scratches.

If the movement amount (close amount) L1 and the movement amount (close amount) L2 are the same amount, the movement speeds of the upper belt 611A and the lower belt 611B with respect to the seat P in the width direction are the same. The amount of rubbing can be made uniform.

Further, the movement amount L1 and the movement amount L2 may be different amounts. For example, if the amount L2 of the lower belt 611B in contact with the surface opposite to the image surface (liquid application surface) of the sheet P is made larger than the amount L1 of the upper belt 611A, the surface of the sheet P which is the image surface Since the amount of rubbing can be made smaller than that of the back surface, the influence on image scratches can be reduced.

In this way, control is performed to correct the meandering of each belt 611 so that the sum L3 of the movement amounts L1 and L2 in the width direction of each belt 611 falls within a predetermined value. As a result, the occurrence of image scratches is suppressed.

Further, if the moving speed of the belt 611 in the width direction is significantly different between the upper and lower belts, the sheet P (liquid applying surface) rubs against the belt 611 and image scratches are likely to occur. The movement of the belt 611B in the belt width direction is the same.

The upper belt 611A and the lower belt 611B do not have to move in the belt width direction exactly the same. For example, the lower belt 611B may move faster than the upper belt 611A. However, at this time, it is preferable that the vertical speed difference is such that the seat P is not pulled by the movement of the lower belt 611B.

On the other hand, the upper and lower belts 611 are controlled separately to correct the meandering. That is, when the upper limit of the meandering amount of each belt is reached, the belt moves to the opposite side, and when the upper limit of the meandering amount of the other side is reached, the opposite side is used. If the control of repeating the movement to is performed, image scratches due to rubbing of the liquid-applied surface of the sheet P are likely to occur.

Next, an example of the relationship between the amount of residual solvent in the sheet P sent to the sheet straightening device 601 and the straightening effect on the deformation of the sheet P will be described with reference to FIG. FIG. 10 is an explanatory diagram provided for the same explanation.

The horizontal axis of FIG. 10 represents the amount of residual solvent, and the vertical axis represents the degree of deformation of the sheet P from rank 0 to rank 5. It is assumed that rank 0 has the largest deformation and rank 5 has the least deformation.

In this example, the amount of residual solvent immediately after drying by the drying portion 300 is ^{less than 500 [mg / m 2} ] for the sheet P1, 1600 [mg / m ² ] for the sheet P2, and 2100 [mg / m] for the sheet P3. ² ].

At this time, the deformation rank a1 of the sheet P1 is "0", the deformation rank a2 of the sheet P2 is "1", and the deformation rank a3 of the sheet P3 is "2.5".

By passing such sheets P1 to P3 through the sheet straightening section 600 in a high-speed mode (relatively high transport speed), the sheets P1 to P3 transition to the deformation ranks b1, b2, and b3, respectively, and the deformation ranks are all increased. (Less deformation).

Further, by passing the sheet P2 through the sheet straightening section 600 in the low speed mode (conveying speed lower than the high speed mode), the sheet P2 shifts to the deformation rank c, and the deformation rank becomes higher than in the high speed mode (deformation occurs). Less).

Further, by passing the sheet P2 through the sheet straightening section 600 in the low speed mode and raising the heating temperature of the heater 604, the sheet P2 transitions to the deformation rank d, and the deformation rank becomes higher than in the constant speed mode. (Less deformation).

From this result, the larger the amount of residual solvent in the sheet P, the less the deformation of the sheet P immediately after drying. Further, when the residual solvent amount is ^{larger than that when the amount is less than 500 [mg / m 2} ], the correction effect (the amount by which the deformation is reduced by the correction) is increased. Further, when the heating temperature of the sheet straightening unit 600 is high and the mode is low speed mode (when the amount of heat input is large), the straightening effect is improved. Therefore, the amount of residual solvent is preferably 500 [mg / m ² ] or more.

That is, by increasing the amount of residual solvent in the sheet P that is deformed such as a cock ring, the straightening effect in the sheet straightening section 600 can be enhanced. In order to increase the amount of residual solvent, the degree of drying (degree of drying) in the drying portion 300 may be lowered, that is, a semi-dried state in which the drying portion 300 is not completely dried may be obtained.

Next, an example of the relationship between the belt coating of the belt pair and the image scratch will be described with reference to FIG. FIG. 11 is an explanatory diagram for the same explanation.

In the present embodiment, as described above, the upper belt 611A and the lower belt 611B of the belt pair 602 are coated with PFA (perfluoroalkoxy alkane) to form a fluororesin layer (film).

The horizontal axis of FIG. 11 represents the amount of residual solvent, and the vertical axis represents the area ratio (broken area ratio) of the portion destroyed when the image is rubbed (rubbed). FIG. 11A shows the case of a belt having a fluororesin layer of PFA, and FIG. 11B shows the case of a belt of PI (polyimide). Further, the belt temperature (probe temperature) is 130 ° C. and 150 ° C. as an example.

From FIG. 7, it can be seen that by using a belt having a fluororesin layer, image scratches can be suppressed as compared with a belt having no fluororesin layer.

Next, an example of the relationship between the coating of the belt pair and the amount of rubbing (rubbing amount) and the image scratch will be described with reference to FIG. FIG. 12 is an explanatory diagram for the same explanation.

The horizontal axis of FIG. 12 represents the amount of rubbing, and the vertical axis represents the area ratio (broken area ratio) that is white when the image is rubbed (rubbed). In this case, the amount of residual solvent is 1261 mg / m ² ).

From FIG. 12, it can be seen that when the amount of rubbing is reduced, image scratches are less likely to occur.

Then, in relation to the amount of rubbing, the amount of residual solvent ^{is preferably 1300 mg / m 2} or less.

Next, an example of heating control of the drying device will be described with reference to the flow chart of FIG.

First, the type information of the sheet P is acquired (step S1, hereinafter, simply referred to as "S1"), and the sheet P stored in the storage means 803 based on the acquired type information of the sheet P is stored. It is determined whether or not the sheet is thin (hereinafter referred to as "thin paper") (S2). The "thin paper" is, for example, 158 gsm or less.

Then, when the sheet P is thin paper, the radiant heater 313 is turned on to lower the output (S3). On the other hand, when the sheet P is not thin paper, that is, when the sheet P is a thick sheet (hereinafter referred to as "thick paper"), the radiant heater 313 is turned on to increase the output (S4). ). The "thick paper" is, for example, 158 gsm to 450 gsm.

Here, by lowering the output of the radiant heater 313 (lowering the heat generation temperature), the heating temperature with respect to the sheet P becomes lower, so that the degree (degree) of drying of the sheet P becomes lower, and the sheet P is in a semi-dry state (semi-dry state). The above-mentioned residual solvent amount is large).

On the other hand, by increasing the output of the radiant heater 313 (increasing the heat generation temperature), the heating temperature with respect to the sheet P becomes high, so that the degree (degree) of drying of the sheet P becomes high, and the sheet P becomes a predetermined dry state. Become.

After that, it is determined whether or not the sheet P has passed through the drying portion 300 (S5), and when the sheet P has passed through the drying portion 300, it is determined whether or not printing is completed (S6). Then, if the printing is not completed, the process returns to step S2, and when the printing is completed, the radiant heater 313 is turned off (S7) to end the process.

As described above, when the sheet P is a thin paper, the degree of drying is set to a semi-dry state, and the sheet P is sent to the sheet straightening device 601 of the subsequent sheet straightening section 600.

As a result, in the case of thin paper in which cockling is likely to occur, the straightening effect of the sheet P by the sheet straightening portion 600 is enhanced, and the sheet P can be reliably straightened.

When the sheet P is thick paper, cockling is unlikely to occur, so that no inconvenience occurs even if the sheet P is dried to a required dry state.

Next, the meandering correction control in the sheet straightening device 601 will be described with reference to the flow chart of FIG.

First, the type information of the sheet P is acquired (S11), and the sheet P stored in the storage means 803 based on the acquired type information of the sheet P is a thin sheet (hereinafter referred to as "thin paper"). Whether or not it is determined (S12).

Then, when the sheet P is thin paper, meandering correction is performed so that the moving speed in the belt width direction falls within the specified value V1 (S13). The specified value V1 is set based on the allowable value of the amount of the sheet P rubbed by the belt of the belt vs. 602 when straightening the thin paper.

For example, assuming that the total amount of movement in the width direction of each belt is L3 with respect to the time t through which the sheet P (thin paper) passes through the region T that sandwiches and conveys the sheet P, the specified value V1 is L3 / t. Desired.

On the other hand, when the sheet P is not thin paper, that is, when the sheet P is a thick sheet (hereinafter referred to as "thick paper"), the moving speed in the belt width direction is a specified value V2 (V2> V1). ), The meandering correction is performed (S14).

For example, assuming that the total amount of movement in the width direction of each belt is L4 (> L3) with respect to the time t through which the sheet P (thin paper) passes through the region T that sandwiches and conveys the sheet P, the specified value V2 is It is calculated at L4 / t. When the sheet P is thin paper, the total amount of movement L3 in the width direction of each belt is smaller than the total amount L4 when the sheet P is thick paper. This is because the image is more easily destroyed than the thick paper because it is sent to the straightening device 601.

After that, the above process is repeated until the meandering correction is completed (S15), and when the meandering correction is completed, this process is terminated.

That is, as described above, when the sheet P is thin paper, the drying device 301 sends the sheet P into a semi-dried state in which the amount of residual solvent in the sheet P increases, and sends the sheet P to the sheet straightening device 601 to enhance the sheet straightening effect. ..

Therefore, when the sheet P is thin paper, the liquid-applied surface of the sheet P and the upper belt 611A (including the lower belt 611B in the case of both sides) are slid when performing the meandering correction of the belt vs. 602 in the sheet straightening device 601. As the amount of rubbing increases, image scratches are likely to occur.

Therefore, when the sheet P is thin paper, the upper belt 611A is slowly moved by reducing the specified value that defines the movement (movement amount or movement speed) in the width direction as compared with the case where the sheet P is thick paper. Return at a speed and correct the meandering so that the amount of rubbing is reduced.

As a result, it is possible to suppress the occurrence of image scratches even on the thin paper sheet P in which image scratches are likely to occur.

On the other hand, when the sheet P is thick paper, it is dried to a sufficiently dry state by the drying device 301 as described above, so that the occurrence of image scratches due to rubbing against the belt pair 602 is suppressed and the sheet P is quickly dried. There is no problem even if the upper belt 611A is returned to.

Next, the second embodiment of the present invention will be described with reference to FIG. FIG. 15 is a side explanatory view of the sheet straightening device according to the same embodiment.

In the present embodiment, an inlet sensor 618 for detecting the tip of the sheet P by the presence or absence of the sheet P is arranged on the inlet side of the sheet straightening device 601, and the rear end of the sheet P is detected by the presence or absence of the sheet P on the exit side. The outlet sensor 619 for the purpose is arranged.

Then, based on the detection results of the inlet sensor 618 and the outlet sensor 619, meandering is performed so that the moving speed in the belt width direction falls within a predetermined predetermined value only while the sheet P passes through the sheet straightening device 601. I am correcting.

Next, the meandering correction control in the second embodiment will be described with reference to the flow chart of FIG.

First, when the rotational drive of the transport rollers 621A and 621B is started (S21), the meandering correction control means 801 starts the meandering correction of the belt 611 with the correction amount A (S22).

The correction amount A at this time is set to a large amount of movement in the belt width direction. This is to control the upper belt 611A and the lower belt 611B to positions closer to appropriate values when the seat P is received by the seat straightening device 601. Further, even if the amount of movement in the width direction is set to be large, the problem of image scratches does not occur because the sheet P is not sandwiched between the upper belt 611A and the lower belt 611B.

After that, it is determined whether or not the inlet sensor 618 has detected the tip of the sheet P (S23), and when the inlet sensor 618 detects the tip of the sheet P, it is determined whether or not the sheet P is thin paper (S24).

Then, when the sheet P is thin paper, meandering correction is performed so that the moving speed in the belt width direction falls within the specified value V1 (A> V1) (S25). After that, it is determined whether or not the exit sensor 619 has detected the rear end of the seat P (S26), and the meandering correction within the specified value V1 is continued until the exit sensor 619 detects the rear end of the seat P.

On the other hand, when the sheet P is not thin paper, that is, when the sheet P is thick paper, meandering correction is performed so that the moving speed in the belt width direction falls within the specified value V2 (A> V2> V1) ( S27). After that, it is determined whether or not the exit sensor 619 has detected the rear end of the seat P (S28), and the meandering correction within the specified value V1 is continued until the exit sensor 619 detects the rear end of the seat P.

Then, when the outlet sensor 619 detects the rear end of the seat P, it is determined whether or not the rotational drive of the transport roller 621 is stopped (S29).

At this time, if the rotational drive of the transport roller 621 is not stopped, the process returns to step S22, and the correction amount A is temporarily returned to perform meandering correction.

On the other hand, when the rotational drive of the transport roller 621 is stopped, this process is terminated.

When the outlet sensor 619 detects the rear end of the sheet P, it may be determined whether the inlet sensor 618 has detected the tip of the next sheet P and the correction amount of the meandering correction control may be set. At this time, if the next sheet P is not continued, it is determined whether or not the rotational drive of the transport rollers 621A and 621B has stopped, the amount is changed to the correction amount A, and the meandering correction control is executed.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 17 is a flow chart for explaining the meandering correction control in the same embodiment.

In the present embodiment, when the two sheets P pass through the sheet straightening device 601, the meandering is corrected so that the moving speed in the belt width direction falls within a predetermined value.

First, when the rotational drive of the transport rollers 621A and 621B is started (S31), the meandering correction control means 801 starts the meandering correction of the belt 611 with the correction amount A (S32).

After that, it is determined whether or not the inlet sensor 618 has detected the tip of the sheet P (S33), and when the inlet sensor 618 detects the tip of the sheet P, the thickness of the preceding sheet P and the trailing sheet P is increased. It is determined whether or not they are different (S34).

Here, when the thickness of the preceding seat P and the thickness of the trailing seat P are different, the moving speed in the belt width direction is within the specified value V1 (A> V1) until the exit sensor 619 detects the rear end of the seat P. The meandering correction is performed so as to fit in (S35, S36).

Further, when the thicknesses of the preceding sheet P and the succeeding sheet P are not different, it is determined whether or not the sheet P is thin paper (S37).

Then, when the sheet P is a thin paper, the process proceeds to step S35.

On the other hand, when the sheet P is not thin paper, that is, when the sheet P is thick paper, the moving speed in the belt width direction is a specified value V2 (A>) until the outlet sensor 619 detects the rear end of the sheet P. The meandering correction is performed so that it fits within V2> V1) (S38, S39).

Then, when the outlet sensor 619 detects the rear end of the seat P, it is determined whether or not the rotational drive of the transport roller 621 is stopped (S30).

At this time, if the rotational drive of the transport roller 621 is not stopped, the process returns to step S32, and the correction amount A is temporarily returned to perform meandering correction.

On the other hand, when the rotational drive of the transport roller 621 is stopped, this process is terminated.

That is, in order to increase the printing productivity, it is conceivable to shorten the sheet spacing between the preceding sheet P and the next succeeding sheet P.

In this case, each condition of the plurality of sheets P to be sent by the feeding device 120 is acquired. Then, when the inlet sensor 618 detects the tip of the preceding sheet P and the thickness of the preceding sheet and the next succeeding sheet P are different, the meandering correction control means 801 performs meandering correction control within the specified value V1. Execute. Even if the preceding sheet P (thick paper) and the next sheet P (thin paper) are mixed in the sheet straightening device 601, the images of both sheets P can be adjusted by matching the correction conditions of the thin paper where image scratches are likely to occur. Can suppress scratches.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 18 is a flow chart for explaining the meandering correction control in the same embodiment.

In the present embodiment, the meandering is corrected so that the moving speed in the belt width direction falls within a predetermined value only while the sheet P passes through the sheet straightening device 601 regardless of the thickness of the sheet P. ing.

First, when the rotational drive of the transport rollers 621A and 621B is started (S41), the meandering correction control means 801 starts the meandering correction of the belt 611 with the correction amount A (S42).

After that, it is determined whether or not the inlet sensor 618 has detected the tip of the sheet P (S43), and when the inlet sensor 618 detects the tip of the sheet P, until the exit sensor 619 detects the rear end of the sheet P. The meandering correction is performed so that the moving speed in the belt width direction falls within the specified value (S44, S45).

Then, when the outlet sensor 619 detects the rear end of the seat P, it is determined whether or not the rotational drive of the transport roller 621 is stopped (S46).

At this time, if the rotational drive of the transport roller 621 is not stopped, the process returns to step S42, and the correction amount A is temporarily returned to perform meandering correction.

On the other hand, when the rotational drive of the transport roller 621 is stopped, this process is terminated.

Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 19 is a side explanatory view of the sheet straightening device according to the same embodiment.

In the present embodiment, instead of the driven rollers 624A and 624B in the first embodiment, a heating roller 634A for heating the upper belt 611A and a heating roller 634B for heating the lower belt 611B are arranged.

With this configuration, the upper belt 611A and the lower belt 611B can be heated before the upper belt 611A and the lower belt 611B come into contact with the seat P, and the upper belt 611A and the lower belt 611B are brought to a constant temperature. It can be brought into contact with the sheet P in a state where the temperature has been raised.

As a result, the heat generated by the roller 603, which is the heating roller on the most upstream side in the transport direction of the sheet P, is used to heat the sheet P, and the sheet P can be efficiently corrected.

Next, the sixth embodiment of the present invention will be described with reference to FIG. FIG. 20 is a side explanatory view of the sheet straightening device according to the same embodiment.

In the present embodiment, the upper roller 603A is arranged so as to be movable (here, it can be moved up and down) as shown by an arrow. The lower roller 603B may be movably arranged in place of the upper roller 603A or in combination with the upper roller 603A.

Thereby, the winding angle of the sheet P with respect to the roller 603 can be changed. For example, when the sheet P is thick, the transport load can be reduced by reducing the winding angle. Further, since the tension on the seat P of the portion wound around the roller 603 can be weakened, image scratches due to meandering correction of the upper belt 611A and the lower belt 611B can be suppressed.

Next, a seventh embodiment of the present invention will be described with reference to FIG. FIG. 21 is a side explanatory view of the sheet straightening device according to the same embodiment.

In the present embodiment, a temperature sensor 641 for detecting the temperature of each roller 603 and a belt temperature sensor 642 for detecting the temperatures of the upper belt 611A and the lower belt 611B are arranged.

Since the purpose of the belt heating roller 634 is to raise the temperature of the belt, the temperature (belt temperature) of the upper belt 611A and the lower belt 611B is monitored, and the temperature is fed back to control the heater built in the belt heating roller 634.

It is also possible to control the belt temperature by measuring the relationship between the belt temperature and the surface temperature of the belt heating roller 634 in advance and measuring the surface temperature of the belt heating roller 634.

Further, the surface temperature of the roller 603 is detected by the temperature sensor 641 and the heat generation temperature of the heater 604 is controlled to keep the surface temperature of the roller 603 constant.

The width direction position of the temperature sensor 641 is arranged in the center of the roller because the transport reference of the sheet P is in the center. However, if the temperature relationship in the width direction is known in advance, the roller It is not limited to the center.

Next, an eighth embodiment of the present invention will be described with reference to FIG. FIG. 22 is a side explanatory view of the sheet straightening device according to the same embodiment.

In the present embodiment, the lower belt 611B uses a belt 611Ba that does not have a fluororesin layer.

Since the lower belt 611B contacts the surface of the sheet P opposite to the liquid-applied surface in single-sided printing, it does not participate in the occurrence of image scratches. Further, since the lower belt 611B passes through the drying portion 300 twice in double-sided printing and comes into contact with the first surface where the amount of residual solvent is reduced, the occurrence of image scratches is suppressed even when there is no fluororesin layer. There is.

Thereby, the cost can be reduced.

In the above embodiment, the printing device 1 includes a printing unit 200 and a drying device 301 according to the present invention, or a device 500 for drying and straightening a sheet. However, the printing unit 200 is used as a printing device. The printing system can also be configured by the drying device 301 according to the present invention or the device 500 that dries and straightens the sheet.

In each of the above embodiments, the sheet straightening device is described as an example in which the sheet is conveyed in the horizontal direction (horizontal direction), but the sheet may be conveyed in the vertical direction or diagonally. it can.

1 Printing device 100 Carry-in section 200 Printing section 300 Drying section 301 Drying device 310 Drying mechanism section 313 Radiation heater 320 Suction transfer mechanism section 400 Discharge section 600 Sheet straightening section 601 Sheet straightening device 602 Belt vs. 603 Roller 604 Heater 611A Upper belt 611B Lower Belt 660 Serpentine correction mechanism 670 Belt position detection means 801 Serpentine correction control means 811 Drying control means

Claims (13)

A pair of belts that sandwich and convey a sheet to which liquid is applied, and
A plurality of curved members that give curvature to the pair of belts,
A heating means for heating the sheet via at least one belt of the pair of belts,
A belt position detecting means for detecting the position in the width direction of each belt of the pair of belts,
A meandering correction means that corrects the meandering of each belt based on the detection result of the belt position detecting means, and
A means for controlling the meandering correction means and a means for controlling the meandering correction means are provided.
The pair of belts can move in the width direction of the belt along the curved surface of the curved surface member in a state of being in contact with the curved surface member.
At least one of the belts in contact with the liquid-coated surface of the sheet has a fluororesin layer on the surface.
The controlling means is a sheet straightening device that controls to correct the meandering of the belts so that the sum of the movement amounts of the belts in the width direction falls within a predetermined value. The sheet straightening device according to claim 1, wherein the controlling means controls to correct the meandering of the belts so that the amount of movement of the belts in the width direction is the same. The sheet straightening device according to claim 1 or 2, wherein the controlling means controls to correct the meandering of the belts so that the moving speeds of the belts in the width direction are the same. Among the plurality of curved surface members, the length of the circumferential region that the sheet imitates the curved surface member on the most upstream side in the sheet transport direction is larger than the length of the circumferential region that the sheet imitates the other curved surface member. The sheet straightening device according to any one of claims 1 to 3, characterized in that it is short. Among the plurality of curved surface members, the curved surface member on the most upstream side in the sheet transport direction is attached to the belt in the pair of belts which is in contact with the surface opposite to the surface to which the liquid of the sheet is applied. The sheet straightening device according to any one of claims 1 to 4, characterized in contact. The sheet straightening apparatus according to any one of claims 1 to 5, wherein the fluororesin layer contains PFA and PTFE. The sheet correction according to any one of claims 1 to 6, wherein the specified value when the thin sheet is conveyed is smaller than the specified value when the thick sheet is conveyed. apparatus. Claims 1 to 7 are characterized in that the specified value is set based on an allowable value of the amount of the sheet rubbed by each belt of the pair of belts when the thin sheet is straightened. The sheet straightening device according to any one of. The means for controlling the belt according to any one of claims 1 to 8, wherein the means for controlling the belt is controlled to correct the meandering of each belt so as to be within the specified value only while the sheet is passing. Sheet straightening device. The pair of belts is composed of an upper belt and a lower belt in the height direction.
The sheet straightening device according to any one of claims 1 to 9, wherein the tension of the lower belt is equal to or less than the tension of the upper belt. A printing apparatus comprising the sheet straightening apparatus according to any one of claims 1 to 10. A means for applying a liquid to the sheet and
A drying means for drying the sheet to which the liquid is applied is provided.
The printing device according to claim 11, wherein the sheet straightening device is arranged on the downstream side of the drying means. A printing device that prints on the sheet,
A printing system comprising the sheet straightening apparatus according to any one of claims 1 to 10.

Images