JP7494451B2 - Processing liquid application device, printing device - Google Patents

Description

The present invention relates to a treatment liquid application device and a printing device.

Some printing devices are equipped with a pretreatment means (coating device) that applies (coats) a treatment liquid to the sheet material before printing.

A treatment liquid application device is known that has a coating roller that applies treatment liquid to a recording medium and a pressure roller that presses the recording medium against the coating roller, and when coating of the treatment liquid begins, when the coating roller and pressure roller are pressed together during accelerated transport of the recording medium to start coating, the transport speed V3 of the recording medium is greater than the peripheral speed V2 of the coating roller (V3>V2) (Patent Document 1).

JP 2013-022874 A

However, in a treatment liquid application device (treatment liquid application device), the conveying speed changes depending on, for example, the type of sheet material, and there is a problem in that a speed difference occurs between the application rotor and the upstream conveying rotor and the downstream conveying rotor, causing a jam.

The present invention was made in consideration of the above problems, and aims to prevent the occurrence of sheet material jams.

In order to solve the above problems, a treatment liquid application device according to the present invention comprises:
a coating rotor that applies a treatment liquid to a sheet material;
an upstream conveying rotary body disposed upstream of the coating rotary body and configured to convey the sheet material;
a downstream conveying rotary body disposed downstream of the coating rotary body and configured to convey the sheet material;
a control unit for controlling the linear speed of the coating rotor to be equal to or higher than the linear speed of the upstream transport rotor and the linear speed of the downstream transport rotor to be equal to or higher than the linear speed of the coating rotor,
The control means is configured to perform the control based on the linear speed of the upstream transport rotor until a predetermined number of the sheet materials have passed the coating rotor, with the first sheet being used as a reference, and to perform the control based on the linear speed of the downstream transport rotor after the predetermined number of the sheet materials have passed the coating rotor.

The present invention can prevent sheet material from jamming.

1 is a schematic explanatory diagram of a printing apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view illustrating a discharge unit of the printing apparatus. FIG. 4 is an explanatory diagram of a pretreatment unit (coating device) in the embodiment. FIG. 4 is a block diagram illustrating a portion relating to roller rotation control in the embodiment. 10 is an explanatory diagram illustrating the relationship between the thickness of a sheet material P and the linear velocity. FIG. FIG. 4 is an explanatory diagram for explaining the relationship between the magnitude of pressure and linear velocity. FIG. 1 is an explanatory diagram for explaining the relationship between single-sided coating and double-sided coating and line speed. FIG. 4 is an explanatory diagram for explaining the relationship between the amount of coating and the linear velocity. 11 is an explanatory diagram for explaining a combination of a thickness of a sheet material, a pressure force, and a coating amount. FIG. 13 is an explanatory diagram of a table for correcting (changing) the linear velocity of the applying roller; FIG. 13 is an explanatory diagram of a table for correcting (changing) the linear speed of the upstream transport roller pair; FIG. 13 is an explanatory diagram of a table for correcting (changing) the linear speed of the upstream transport roller pair; FIG. FIG. 13 is an explanatory diagram for explaining the degree of linear velocity correction A to H. 11 is an explanatory diagram illustrating an example of a correction amount when correcting the linear velocity of an applying roller; FIG. FIG. 11 is a block diagram illustrating a portion relating to roller rotation control in a second embodiment of the present invention. FIG. 11 is a flow chart illustrating rotation speed control (linear speed correction control). 13 is an explanatory diagram illustrating a change in the center distance between the application roller and the pressure roller in the third embodiment of the present invention. FIG. 10 is an explanatory diagram illustrating an example of a relationship between an axis-to-axis distance and a linear velocity of an applying roller; FIG. FIG. 4 is a block diagram illustrating a portion relating to roller rotation control in the embodiment.

A printing device as a device for ejecting liquid according to a first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic diagram of the printing device.

The printing device 1 includes an input section 10 for inputting sheet material P, a pre-processing section 20, a printing section 30, a drying section 40, an unloading section 50, and an inversion mechanism section 60. In the printing device 1, the pre-processing section 20, which is a pre-processing means, applies (coats) a pre-processing liquid to the sheet material P input (supplied) from the input section 10 as necessary, the printing section 30 applies liquid to perform the required printing, the drying section 40 dries the liquid adhering to the sheet material P, and then the sheet material P is discharged to the unloading section 50.

The loading section 10 includes an input tray 11 (lower input tray 11A, upper input tray 11B) that stores multiple sheet materials P, and a feeding device 12 (12A, 12B) that separates and sends out the sheet materials P one by one from the input tray 11, and supplies the sheet materials P to the pre-processing section 20.

The pre-treatment unit 20 includes an application unit 21, which is a treatment liquid application means that applies a treatment liquid to the printing surface of the sheet material P, for example, to aggregate the ink coloring material and prevent show-through.

The printing unit 30 includes a drum 31, which is a support member (rotating body) that supports the sheet material P on its circumferential surface and rotates, and a liquid ejection unit 32 that ejects liquid toward the sheet material P supported by the drum 31.

The printing unit 30 also includes a transfer cylinder 34 that receives the sheet material P sent from the pre-processing unit 20 and transfers the sheet material P between the drum 31, and a transfer cylinder 35 that receives the sheet material P transported by the drum 31 and transfers it to the reversing mechanism unit 60.

The sheet material P transported from the pre-processing section 20 to the printing section 30 has its leading edge gripped by a gripping means (sheet gripper) provided on the transfer cylinder 34, and is transported as the transfer cylinder 34 rotates. The sheet material P transported by the transfer cylinder 34 is transferred to the drum 31 at a position opposite the drum 31.

A gripping means (sheet gripper) is also provided on the surface of the drum 31, and the leading edge of the sheet material P is gripped by the gripping means (sheet gripper). A number of suction holes are formed in a distributed manner on the surface of the drum 31, and the suction means generates a suction airflow that flows inward from the required suction holes of the drum 31.

Then, the sheet material P transferred from the transfer cylinder 34 to the drum 31 has its leading edge gripped by the sheet gripper, is adsorbed and supported on the drum 31 by the suction airflow from the suction means, and is transported as the drum 31 rotates.

The liquid ejection section 32 is equipped with ejection units 33 (33A to 33D) which are liquid ejection means. For example, ejection unit 33A ejects cyan (C) liquid, ejection unit 33B ejects magenta (M) liquid, ejection unit 33C ejects yellow (Y) liquid, and ejection unit 33D ejects black (K) liquid. In addition, ejection units that eject special liquids such as white and gold (silver) can also be used.

The ejection operation of each ejection unit 33 of the liquid ejection section 32 is controlled by a drive signal corresponding to the printing information. When the sheet material P supported on the drum 31 passes through the area facing the liquid ejection section 32, liquid of each color is ejected from the ejection unit 33, and an image corresponding to the printing information is printed.

The reversing mechanism 60 is a mechanism that reverses the sheet material P by a switchback method when performing double-sided printing on the sheet material P handed over from the transfer cylinder 35, and the reversed sheet material P is sent back upstream of the transfer cylinder 34 through the conveying path 61 of the printing unit 30.

The drying section 40 dries the liquid that has been applied to the sheet material P by the printing section 30. This causes the water content in the liquid and other liquid components to evaporate, the colorant contained in the liquid to be fixed on the sheet material P, and curling of the sheet material P is suppressed.

The discharge section 50 is equipped with a discharge tray 51 on which multiple sheet materials P are stacked. The sheet materials P conveyed from the drying section 40 are stacked and held on the discharge tray 51 in sequence.

Next, an example of a head unit constituting a discharge unit will be described with reference to FIG. 2. FIG. 2 is a plan view of the head unit as viewed from the nozzle surface side.

The head unit 300 has multiple heads 100 that eject liquid arranged in a staggered pattern on a head mounting member 302.

Each head 100 has multiple nozzle rows (four rows are shown here as an example, but this is not limited to this) in which multiple nozzles 104 that eject liquid are arranged.

In this embodiment, the printing means is described as having a liquid ejection means, but printing can also be performed using means other than liquid ejection.

Next, the pre-treatment unit (coating unit) configured in the treatment liquid application device according to the present invention will be described with reference to FIG. 3. FIG. 3 is an explanatory diagram of the pre-treatment unit.

The pre-treatment section 20 includes an application section 21, which is a treatment liquid application means (application means) that applies and applies a treatment liquid 201 to the sheet material P, an upstream conveying path 22, a downstream conveying path 23, a reverse conveying path 24, and a straight conveying path 25.

The upstream transport path 22 is a path that transports the sheet material P sent to the pre-processing section 20 toward the coating section 21, and is provided with transport roller pairs 221 and 222 that transport the sheet material P in a direction perpendicular to the transport direction.

The downstream transport path 23 is a path that transports the sheet material P onto which the treatment liquid 201 has been applied in the application unit 21 toward the downstream printing unit 30, and is provided with multiple transport roller pairs 231.

The reverse conveying path 24 is a path that, when applying the treatment liquid 201 to both sides of the sheet material P, receives the sheet material P with the treatment liquid 201 applied to one side from the middle of the downstream conveying path 23, reverses it, and sends it again toward the conveying roller pair 222 of the upstream conveying path 22, and is provided with multiple conveying roller pairs 241.

In addition, a branch claw 26 is provided midway along the downstream conveying path 23 to switch to the entrance of the reverse conveying path 24.

The straight conveying path 25 is a path that does not apply the treatment liquid 201 to the sheet material P sent from the loading section 10 in the coating section 21, but instead joins the downstream conveying path 23. When the coating section 21 is capable of not applying the treatment liquid 201, it is also possible to transport the sheet material P without applying the treatment liquid 201 from the upstream conveying path 22 through the downstream conveying path 23 without separately providing the straight conveying path 25.

The coating unit 21 includes a treatment liquid storage tank (supply pan) 202 that contains treatment liquid 201, a pumping roller 203 that pumps up the treatment liquid 201, intermediate rollers 204 and 205 that perform film thickness control, and a coating roller 206 that is a coating rotor that applies the treatment liquid 201 to the sheet material P. The coating unit 21 also includes a pressure roller 207 that is a pressure rotor that faces the coating roller 206, and a pressing roller 208 that presses against the pressure roller 207.

This application unit 21 draws up the treatment liquid 201 with a drawing up roller 203, controls the film thickness with intermediate rollers 204 and 205, transfers the treatment liquid 201 to an application roller 206, and forms a liquid film of the treatment liquid 201 of the required thickness on the peripheral surface of the application roller 206.

The sheet material P is conveyed via the upstream conveying roller pair 222, which is an upstream conveying rotating body, and passes through the nip between the application roller 206 and the pressure roller 207, so that the treatment liquid 201 is applied to the sheet material P. The upstream conveying roller pair 222 is a pair of an upstream conveying drive roller 222a and a driven roller 222b.

The sheet material P coated with the treatment liquid 201 is transported further downstream via a downstream transport roller pair 231, which is a downstream transport rotating body of the downstream transport path 23, and multiple transport roller pairs 232 and 233, or is transported to the reverse transport path 24. The downstream transport roller pair 231 is a pair of a downstream transport drive roller 231a and a driven roller 231b.

In this embodiment, of the two rollers of the conveying roller pair 231, 232, the conveying roller that is the rotating body that comes into contact with the application surface of the sheet material P to which the treatment liquid 201 is applied is used as the drive roller, and a bead roller with fine particles provided on the peripheral surface is used. This makes it possible to reduce the treatment liquid 201 applied to the sheet material P being scraped off by the conveying roller pair 231, 232.

Next, the part related to roller rotation control in this embodiment will be explained with reference to the block diagram in Figure 4.

The rotation control means 801 controls the rotation of the application roller 206 via the roller drive unit 811. The rotation control means 801 drives and controls the upstream transport drive roller 222a via the roller drive unit 812 to control the rotation of the upstream transport roller pair 222. The rotation control means 801 drives and controls the downstream transport drive roller 231a via the roller drive unit 813 to control the rotation of the downstream transport roller pair 231.

The storage means 802 stores a table that predefines the relationship between the pressure applied by the pressure roller 207, the type of sheet material P, the amount of application, and the rotation speed (linear speed) of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231.

The rotation control means 801 inputs information on the pressure, thickness of the sheet material P, and amount of coating, and reads out the rotation speed (linear speed) of the coating roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 from a table stored in the memory means 802.

Then, the rotation control means 801 controls the rotation speed (linear speed) of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 according to the read rotation speed (linear speed) to control the linear speed of the application roller 206 to be equal to or higher than the linear speed of the upstream conveying roller pair 222, and the linear speed of the downstream conveying roller pair 231 to be equal to or higher than the linear speed of the application roller 206.

In addition, by providing each piece of information on the pressure, thickness of the sheet material P, and amount of application to a table in the storage means 802, information on the corresponding rotation speed (linear speed) of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 can be provided from the storage means 802 to the rotation control means 801.

Next, the fluctuation of the conveying speed in the pre-processing section will be described with reference to Figures 5 to 10. Figure 5 is an explanatory diagram for explaining the relationship between the thickness of the sheet material P and the linear speed, Figure 6 is an explanatory diagram for explaining the relationship between the magnitude of the pressure force and the linear speed, Figure 7 is an explanatory diagram for explaining the relationship between single-sided coating (application) and double-sided coating (application) and the linear speed, and Figure 8 is an explanatory diagram for explaining the relationship between the magnitude of the coating amount and the linear speed.

Linear speed can be expressed as linear speed (m/s) = rotation speed (rps) x circumference (usually πd), so as the circumference of the rotating body increases, the linear speed increases.

The pressure roller 207, which is made of a metal roller, is pressed (applies pressure) against the application roller 206, which is made of a rubber roller.

As shown in FIG. 5A, when the sheet material P is thin paper Pa, the sheet material P does not absorb the pressure force, and the pressure force is applied directly to the application roller 206, resulting in a large deformation of the application roller 206. As a result, the circumferential length of the application roller 206 expands significantly, and the linear speed increases.

In contrast, as shown in FIG. 5B, when the sheet material P is thick cardboard Pb, the sheet material P absorbs the pressure force and reduces the pressure force applied to the application roller 206, so the deformation of the application roller 206 is relatively small. As a result, the extension of the circumferential length of the application roller 206 is small, and the linear speed is relatively slow.

As shown in FIG. 6A, when the pressure is large, the deformation of the application roller 206 is large. Therefore, the circumferential length of the application roller 206 is expanded by a large amount, and the linear speed is increased.

In contrast, as shown in FIG. 6B, when the applied pressure is small, the amount of deformation of the application roller 206 is relatively small. Therefore, the amount of extension of the circumferential length of the application roller 206 is small, and the linear speed is relatively slow.

As shown in FIG. 7A, when coating one side of cardboard, the sheet material P absorbs the pressure force, and the amount of deformation of the coating roller 206 is relatively small. Therefore, the amount of extension of the circumferential length of the coating roller 206 is small, and the linear speed is relatively slow.

In contrast, as shown in FIG. 7(b), when applying treatment liquid to the other side of cardboard that already has treatment liquid applied to one side, the sheet material P has a reduced rigidity due to the treatment liquid already applied to it, and is easily deformed and does not absorb the pressure force, so the amount of deformation of the application roller 206 is relatively large. As a result, the amount of extension of the circumferential length of the application roller 206 is small, and the linear speed is relatively fast.

As shown in FIG. 8(a), when the application amount (application amount) is small (few), the impact on the rigidity of the sheet material P is small, the sheet material P absorbs the pressure force, and the amount of deformation of the application roller 206 is relatively small. Therefore, the amount of extension of the circumferential length of the application roller 206 is small, and the linear speed is relatively slow.

In contrast, as shown in FIG. 8(b), when the application amount (application amount) is large (large), the rigidity of the sheet material P decreases and it easily deforms and does not absorb the pressure force, so the application roller 206 deforms relatively more. As a result, the extension of the circumferential length of the application roller 206 is small, and the linear speed is relatively fast.

Next, the relationship between the paper type (thickness), pressure, and coating amount of the sheet material P will be described with reference to FIG. 9. FIG. 9 is an explanatory diagram for explaining the combination of the thickness, pressure, and coating amount of the sheet material.

First, the conditions for changing the pressure are as follows. That is, when the thickness of the sheet material P is thick, the pressure is increased, and when the thickness is thin, the pressure is decreased. When the amount of application is to be reduced, the pressure is increased, and when the amount of application is to be increased, the pressure is decreased.

The conditions for changing the coating amount are as follows. In other words, the coating amount varies depending on the components of the coating layer of the sheet material P, but if the paper type (category) is the same, the coating amount can be made constant by keeping the paper passing conditions of the coating device the same. For paper type A, which is known to have a tendency to increase the coating amount, the pressure is increased and the coating amount is reduced. On the other hand, for paper type B, which is known to have a tendency to decrease the coating amount, the pressure is decreased and the coating amount is increased.

This allows control so that the application amount remains within the target range.

Therefore, when the paper type (thick paper, thin paper: thickness), pressure, and application amount of the sheet material P are set to large and small, combinations NO1 to NO8 are possible as shown in Figure 9.

The degree of influence on the linear speed of the application roller 206 is most evident when the paper is thick or thin, followed by the amount of pressure applied, and then the amount of application.

When the sheet material P is thick paper, the sheet material P absorbs the pressure force, so the linear speed of the application roller 206 is generally slower. When the pressure force is small, the linear speed of the application roller 206 is even slower. When the amount of application is small, the linear speed of the application roller 206 is even slower.

Therefore, the linear speed of the application roller 206 is the slowest when the combination of "thick paper, small pressure, small application amount" shown in No. 3 in FIG. 9 is selected. The order is then No. 3 → No. 4 → No. 1 → No. 2.

On the other hand, when the sheet material P is thin paper, the sheet material P does not absorb the pressure force, so the linear speed of the application roller 206 is generally faster, and when the pressure force is large, the linear speed of the application roller 206 is even faster. Furthermore, when the amount of application is large, the linear speed of the application roller 206 is even faster.

Therefore, the linear speed of the application roller 206 is the fastest when the combination of "thin paper, high pressure, and large application amount" shown in No. 6 in FIG. 9 is selected. The order is No. 6 → No. 5 → No. 8 → No. 7.

Next, the control of the rotation speed (linear speed) of the application roller 206, the upstream transport roller pair 222, and the downstream transport roller pair 231 will be described with reference to Figs. 10 to 13. Fig. 10 is an explanatory diagram used to explain the tables when correcting (changing) the linear speed of the application roller, Fig. 11 is an explanatory diagram used to explain the tables when correcting (changing) the linear speed of the upstream transport roller pair, and Fig. 12 is an explanatory diagram used to explain the linear speed correction levels A to H.

First, the linear speed relationship between the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 is controlled so that the linear speed of the application roller 206 is equal to or greater than the linear speed of the upstream conveying roller pair 222, and the linear speed of the downstream conveying roller pair 231 is equal to or greater than the linear speed of the application roller 206. In other words, the rotation speeds of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 are controlled so that the linear speed relationship is: upstream conveying roller pair≦application roller≦downstream conveying roller pair.

This allows for stable transport of the sheet material and application (coating) of treatment liquid.

In this case, it is preferable that the difference between the linear speed of the upstream conveyor roller pair 222 and the linear speed of the downstream conveyor roller pair 231 be within 10%.

Therefore, when correcting the linear speed of the application roller 206, the linear speed is controlled using a table such as that shown in FIG. 10. In this case, the linear speed of the upstream conveying roller pair 222 and the linear speed of the downstream conveying roller pair 231 may be linear speeds that satisfy the relationship: upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

When correcting the linear speed of the upstream conveying roller 222, the linear speed is controlled using a table such as that shown in FIG. 11. In this case, the linear speed of the application roller 206 and the linear speed of the downstream conveying roller pair 231 may be linear speeds that satisfy the relationship: upstream conveying roller pair≦application roller≦downstream conveying roller pair.

When correcting the linear speed of the downstream conveying roller pair 231, the linear speed is controlled using a table such as that shown in FIG. 13. In this case, the linear speed of the upstream conveying roller pair 222 and the linear speed of the application roller 206 may be linear speeds that satisfy the relationship: upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

The linear speed corrections A to H in each table are in the order A>B>C>D>E>F>G>H, with A being the fastest and H being the slowest, as shown in Figure 13.

Next, an example of the correction amount when correcting the linear speed of the application roller 206 will be described with reference to FIG. 14. FIG. 14 is an explanatory diagram for the same description.

Here, the paper types are classified into three categories: thick paper, thin paper, and medium thickness paper. The linear speed for medium thickness paper, high pressure, and low coating amount is set as the reference (0% correction), and the correction amount (%) for the reference linear speed is shown.

As mentioned above, these tables are stored in the storage means 802, and the linear speed is corrected by controlling the rotation speed of at least one of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 according to the table, depending on the information on the thickness of the sheet material, the pressure, and the amount of application.

In this way, the linear speed is controlled so that the relationship is upstream conveying roller pair <= application roller <= downstream conveying roller pair, thereby preventing the occurrence of sheet material jams.

Next, a second embodiment of the present invention will be described with reference to Figures 15 and 16. Figure 15 is a block diagram of the roller rotation control in this embodiment, and Figure 16 is a flow diagram explaining the rotation speed control (linear speed correction control).

In this embodiment, an upstream linear speed detection means 822 is provided to detect the linear speed of the upstream conveying roller pair 222, and a downstream linear speed detection means 823 is provided to detect the linear speed of the downstream conveying roller pair 231.

The rotation control means 801 corrects the linear speed of the application roller 206 based on the linear speed of the upstream conveying roller pair 222 detected by the upstream linear speed detection means 822 and the linear speed of the downstream conveying roller pair 231 detected by the downstream linear speed detection means 823, and controls the linear speed to the relationship upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

Referring to FIG. 16, first, when the conveyance (passing) of the sheet material P to the coating unit 21 is started, it is determined whether or not it is the first sheet material P (step S1, hereafter simply referred to as "S1").

Here, for the first sheet material P, the linear speed of the application roller 206 is corrected based on the linear speed of the upstream conveying roller pair 222 so that the relationship is upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

In contrast, if it is not the first sheet of sheet material P, the linear speed of the application roller 206 is corrected based on the linear speed of the downstream conveying roller pair 231 so that the relationship is: upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

In other words, the linear speed of the sheet material P after application, i.e., the linear speed of the downstream transport roller pair 231, is used as the reference (the transport speed of the sheet material P on which the treatment liquid has been applied is used as the reference). However, since the linear speed of the downstream transport roller pair 231 is not the actual linear speed of the sheet material P for the first sheet, the linear speed of the application roller 206 is corrected for the first sheet based on the linear speed of the upstream transport roller pair 222. In this case, after a predetermined number of sheets of sheet material P (e.g., 2 to 3 sheets) have been passed through, it is also possible to switch to control based on the linear speed of the downstream transport roller pair 231.

This simplifies control by allowing the linear speed to be controlled so that the relationship is upstream conveying roller pair <= application roller <= downstream conveying roller pair without using a table as in the first embodiment.

Next, a third embodiment of the present invention will be described with reference to Figures 17 to 19. Figure 17 is an explanatory diagram for explaining the change in the center distance between the application roller and the pressure roller in the third embodiment, Figure 18 is an explanatory diagram for explaining an example of the relationship between the center distance and the linear speed of the application roller, and Figure 19 is a block diagram of the part related to the roller rotation control in the third embodiment.

Referring to Figure 17, the axial distance (axial distance) L between the application roller 206 and the pressure roller 207 is, for example, L1 as shown in Figure 17(a) when no pressure is being applied. In contrast, when the pressure roller 207 is applying pressure to the application roller 206 via the sheet material P, the distance changes to L2 as shown in Figure 17(b) or to L3 as shown in Figure 17(c) depending on the thickness of the sheet material P, the pressure, and the amount of application.

The change in the axial distance L between the application roller 206 and the pressure roller 207 correlates with the change in the deformation amount of the application roller 206, and the linear speed changes depending on the change in the deformation amount of the application roller 206.

The relationship between the center distance L and the speed is as shown in Figure 19. The X-axis shows "center distance when pressure is applied - center distance when no load is applied + sheet material thickness", and the Y-axis shows the linear speed of the application roller.

When the value on the X-axis is zero, the linear speed of the application roller 206 is expressed as (number of rotations x diameter x π). The more negative the X-axis is, in other words, the greater the amount of compression of the application roller 206, the faster the linear speed of the application roller 206 becomes.

Therefore, by detecting the axial distance L between the application roller 206 and the pressure roller 207 and correcting the linear speed of the application roller 206, it is possible to control the relationship so that the upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

In other words, as shown in FIG. 19, the control means includes an axial distance detection means 831 that detects the axial distance between the application roller 206 and the pressure roller 207. The axial distance detection means 831 can be configured as a distance measurement sensor, a linear encoder, etc.

Then, the rotation control means 801 controls the linear speeds of the application roller 206, the upstream conveying roller pair 222, and the downstream conveying roller pair 231 according to the axis distance detected by the axis distance detection means 831 so that the relationship is upstream conveying roller pair ≦ application roller ≦ downstream conveying roller pair.

This makes it possible to control the linear speed so that the relationship is upstream transport roller pair≦application roller≦downstream transport roller pair without using a table as in the first embodiment, simplifying the control.
The first embodiment may be combined with the second and third embodiments.

In this application, printing has the same meaning as image formation, recording, printing, copying, etc. In addition, the treatment liquid application device (treatment liquid application device) of this application can also be applied to a device that performs printing by an electrophotographic process on a sheet material to which treatment liquid (application liquid) has been applied.

1 Printing device 10 Carry-in section 20 Pre-processing section (pre-processing means)
30 Printing section 40 Drying section 50 Discharge section 21 Coating section (treatment liquid application means)
22 Upstream conveying path 23 Downstream conveying path 24 Reverse conveying path 25 Straight conveying path 31 Drum 32 Liquid application section 34 Transfer drum 201 Treatment liquid 206 Coating roller (coating rotary body)
206 Pressure roller (pressure rotating body)
222 Transport roller pair (upstream transport rotating body)
231 Conveying roller pair (downstream conveying rotating body)
801 Rotation control means (means for controlling)

Claims (2)

a coating rotor that applies a treatment liquid to a sheet material;
an upstream conveying rotary body disposed upstream of the coating rotary body and configured to convey the sheet material;
a downstream conveying rotary body disposed downstream of the coating rotary body and configured to convey the sheet material;
a control unit for controlling the linear speed of the coating rotor to be equal to or higher than the linear speed of the upstream transport rotor and the linear speed of the downstream transport rotor to be equal to or higher than the linear speed of the coating rotor,
The control means performs the control based on the linear speed of the upstream transport rotor until a predetermined number of the sheet materials have passed the coating rotor, with the first sheet being used as a reference, and performs the control based on the linear speed of the downstream transport rotor after the predetermined number of the sheet materials have passed the coating rotor. The treatment liquid application device according to claim 1 ;
a printing means for applying a liquid to the sheet material to which the treatment liquid has been applied by the treatment liquid application device, thereby performing printing.

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