JP2014091235A - Processing liquid coating device and image forming system with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing liquid coating device of an ink jet printer that can sufficiently exhibit an effect and function of processing liquid coating, by suppressing insufficiency of a coating amount and coating unevenness or the like of processing liquid to a recording medium.SOLUTION: A processing liquid coating device is provided with speed detection means 44 for a squeeze roller, and speed detection means 46 for a coating roller. A controller 53 previously stores a line speed Na at which a processing liquid amount necessary for coating a recording medium can be supplied, and performs control to press a pressure roller 33 to the coating roller side and start conveyance of the recording medium W by recording medium conveyance means 41, when both of a line speed of the squeeze roller 29 detected by the speed detection means 44 for the squeeze roller and a line speed of the coating roller 31 detected by the speed detection means 46 for the coating roller reach the stored line speed Na.

Description

  The present invention provides a treatment liquid such as a bleeding inhibitor that suppresses image bleeding of an ink jet printer that ejects ink droplets to form an image on a recording medium such as a web, on the recording medium prior to image formation. The present invention relates to a treatment liquid coating apparatus for an inkjet printer to be coated and an image forming system including the same.

  2. Description of the Related Art Inkjet image forming apparatuses are rapidly spreading due to the advantages of low noise, low running cost, and easy colorization. However, when recording on a recording medium other than special paper, in addition to problems with initial quality such as bleeding, density, color tone and show-through, there are problems related to image robustness such as water resistance and weather resistance. Various proposals have been made to solve these problems.

  As a solution to these problems, there is a method for improving image quality by applying a treatment liquid having a function of aggregating ink immediately before ink droplets adhere to a recording medium.

  As a method for applying the treatment liquid, a method of applying to the entire paper surface using a roller is disclosed in Japanese Patent Laid-Open No. 7-156538 (Patent Document 1). FIG. 9 is a schematic cross-sectional view of a processing liquid coating apparatus that applies a processing liquid to paper using a roller in this conventional example.

  As shown in the figure, a sheet 203 is wound around a peripheral surface of a platen roller 201 that is rotated by a drive source (not shown) such as a motor, using a presser chuck 202. On the other hand, the processing liquid 205 is stored in the processing liquid tank 204, and the processing liquid 205 is transferred to the roller surface of the coating roller 208 in a thin film shape by the stirring / supply roller 206 and the transport / thinning rollers 207a and 207b. .

  The application roller 208 rotates while being pressed onto the web 203 wound around the rotating platen roller 201 to apply the treatment liquid 205 to the surface of the web 203. When the portion of the web 203 to which the treatment liquid 205 is applied comes to a position facing the ink jet recording head 209, ink droplets are ejected from the ink jet recording head 209 onto the web 203 to perform recording.

  As described above, the method of applying the processing liquid for improving the image quality quality onto the recording medium with the application roller in advance has a relatively high viscosity as compared with the method of spraying the processing liquid onto the recording medium using the spray head. This is an excellent technique in that even a high-treatment liquid can be applied thinly and image bleeding can be further reduced.

  However, in the conventional processing liquid coating apparatus, in a constant speed region of paper conveyance, the coating roller rotates at the same speed as the printing speed of the printing paper, and the necessary amount of the processing liquid is continuously supplied from the coating roller to the printing paper. However, at the start of printing, the printing paper is pressed and niped from the pressure roller to the coating roller, and the conveyance is started. At this momentary nip, there is a speed difference between the printing paper and the coating roller. Yes.

  In addition, since sufficient processing liquid is not supplied from the squeeze roller to the rotating application roller at the start of printing, the amount of processing liquid cannot be sufficiently supplied from the application roller to the printing paper. As a result, there is a problem that the application of the treatment liquid on the surface of the printing paper causes insufficient application amount or uneven application.

  Similarly, when the paper transport is stopped, a speed difference is generated between the paper and the application roller between the application roller and the paper due to an abrupt braking action of the stop operation. There was a problem that the amount of the treatment liquid could not be sufficiently supplied, resulting in unstable application, resulting in insufficient amount of treatment liquid and uneven coating.

  Japanese Patent Application Laid-Open No. 2011-194619 (Patent Document 2) describes a treatment liquid collected in a nip portion between a coating roller and a squeeze roller by applying a treatment liquid to a printing paper for the purpose of reducing coating unevenness. After applying the liquid, the squeeze roller and the application roller are separated from each other, and the squeeze roller is rotated faster than the application roller while the application roller and the transport roller are separated from each other, and collected in the nip portion between the application roller and the squeeze roller. It is disclosed to recover the processing liquid.

  However, in the invention described in Patent Document 2, no consideration is given to the insufficient coating amount of the processing liquid in the acceleration area at the start of conveyance of the recording medium and the deceleration area at the time of conveyance stop. Insufficient amount of treatment liquid was applied, and unevenness of treatment liquid application was caused.

  An object of the present invention is to solve such drawbacks of the prior art, suppress an insufficient amount of processing liquid applied to the recording medium, and uneven coating, etc., and an ink jet printer capable of fully exhibiting the effects and functions of processing liquid application. The object is to provide a treatment liquid coating apparatus.

In order to achieve the above object, the present invention provides:
For example, a recording medium conveying means such as a conveying roller for conveying a recording medium such as a web;
A supply pan for retaining the processing liquid;
A squeeze roller that pumps up the processing liquid in the supply pan;
An application roller for applying the treatment liquid supplied from the squeeze roller to the recording medium;
A pressure roller that presses the recording medium toward the application roller when the treatment liquid is applied to the recording medium, and sandwiches the recording medium with the application roller;
The present invention is intended for a processing liquid coating apparatus of an ink jet printer including a controller such as a coating apparatus controller to be described later, which controls the operations of the recording medium conveying unit, squeeze roller, coating roller, and pressure roller.

And squeeze roller speed detecting means such as a squeeze roller pulse encoder for detecting the linear speed of the squeeze roller;
A coating roller speed detecting means such as a coating roller pulse encoder for detecting the linear speed of the coating roller is provided,
The controller is
A linear velocity Na capable of supplying a processing liquid amount necessary for the recording medium application is stored in advance;
When the linear speed of the squeeze roller detected by the speed detection means for squeeze roller and the linear speed of the application roller detected by the speed detection means for application roller reach the linear speed Na stored together, The pressure roller is pressed to the application roller side, and the recording medium conveying means is controlled to start conveying the recording medium.

  The present invention has the above-described configuration, and it is possible to suppress an insufficient coating amount of the processing liquid on the recording medium, uneven coating, and the like, and a processing liquid coating apparatus for an inkjet printer that can sufficiently exhibit the effects and functions of the processing liquid coating. Can be provided.

1 is a schematic configuration diagram for explaining a flow of an image forming system according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a processing liquid coating apparatus used in the image forming system, showing a state at the time of coating a processing liquid. It is a schematic block diagram of the process liquid application means in the process liquid application apparatus which concerns on the Example of this invention. It is a characteristic drawing of the processing liquid pumping of the squeeze roller provided in the processing liquid application means. It is a control block diagram of the process liquid coating apparatus which concerns on the Example of this invention. (A) Relationship between web conveyance speed (linear velocity) (V) and time (T), (b) Relationship between squeeze roller rotation speed (linear velocity) (N) and time (T) (same figure) It is a timing chart. It is a flowchart for demonstrating rotation control of a squeeze roller and an application | coating roller, and web conveyance control. It is the timing chart which showed the relationship between the rotational speed (N) and time (T) of the conventional squeeze roller. It is a schematic sectional drawing of the process liquid coating apparatus of the system which apply | coats a process liquid to a paper using the roller in a prior art example.

As described above, the present invention includes squeeze roller speed detection means for detecting the linear speed of the squeeze roller, and application roller speed detection means for detecting the linear speed of the application roller,
The device controller
The linear velocity Na that can supply the processing liquid amount necessary for recording medium application is stored in advance,
When the linear speed of the squeeze roller detected by the speed detection means for squeeze roller and the linear speed of the application roller detected by the speed detection means for application roller reach the linear speed Na stored together, The pressure roller is pressed toward the application roller, and the recording medium conveying means is controlled to start conveying the recording medium.

  By controlling in this way, it is possible to easily and easily suppress the insufficient application of the treatment liquid at the start of printing and the accompanying coating unevenness.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram for explaining the flow of an image forming system according to an embodiment of the present invention.

  As shown in the figure, the web W made of long continuous paper fed out from the paper feeding device 100 is first fed into the treatment liquid coating device 101 and processed on both the front and back surfaces of the web W, respectively. The liquid 22 (see FIG. 3) is applied, and the pretreatment ends.

  Next, the processed web W is sent to the first inkjet printer 102a, and ink droplets are ejected to the front side of the web W to form a desired image. Thereafter, the front and back sides of the web W are reversed by the reversing device 103. Subsequently, the web W is sent to the second inkjet printer 102b, and ink droplets are ejected to the back side of the web W to form a desired image.

  Although not shown, each of the inkjet printers 102a and 102b includes an inkjet recording head that ejects ink droplets onto the web W. After printing on both sides of the web W in this way, the system is sent to a post-processing device (not shown) to perform a predetermined post-processing.

  The overall operation of the paper feeding device 100, the processing liquid coating device 101, the first ink jet printer 102a, the second ink jet printer 102b, the reversing device 103, and the post-processing device is controlled by the host controller 104.

  FIG. 2 is a schematic configuration diagram of the processing liquid coating apparatus 101 used in the image forming system, and shows a state when the processing liquid 22 is applied.

  As shown in the figure, a bearing (not shown) is provided at the end of the roller, and a large number of rotatable guide rollers 1 are installed in the treatment liquid coating apparatus 101 to secure a conveyance path for the web W. doing.

  Reference numeral 2 in the figure denotes an FI roller (feed-in roller) that is rotated by a drive source (not shown) such as a motor, and the FI nip roller (feed-in nip roller) 4 is moved to the FI by a pulling force of a spring (not shown). It is pressed against the roller 2.

  The web W is elastically sandwiched between the FI roller 2 and the FI nip roller 4, and the web W is drawn from the paper feeding device 100 into the processing liquid coating apparatus 101 by rotating the FI roller 2. Can do.

The web W fed out from the FI roller 2 and the FI nip roller 4 is slightly slackened to form an air loop AL.
The web W that has passed through the air loop AL passes between the pass shaft 5 and the edge guide 6. Although not shown, the two pass shafts 5 are arranged in a direction orthogonal to the conveyance direction (arrow direction) of the web W, and the web W passes between the pass shafts 5 in an S shape. A pair of plate-like edge guides 6 are attached to both ends of the pass shaft 5, and the distance between the edge guides 6 is set to be the same as the width of the web W.

  Therefore, the travel position of the web W in the width direction is regulated by the action of the pass shaft 5 and the edge guide 6, and the web W can travel stably. It is possible to prepare a plurality of types of pass shafts 5 having different lengths, select a pass shaft 5 suitable for the width dimension of the web W to be used, and replace the edge guide 6 with the screw or the like on the pass shaft 5. It is supposed to be attached to.

  The web W that has passed between the pass shaft 5 and the edge guide 6 is brought into sliding contact with the tension shaft 7 that is in a fixed state, so that tension is applied to the web W for running stability.

  The web W that has passed through the tension shaft 7 passes between an infeed roller 8 and a feed nip roller 9 that are rotated by a drive source (not shown) such as a motor. Although the feed nip roller 9 is not shown, a plurality of the feed nip rollers 9 are arranged to face each other along the axial direction of the infeed roller 8, and each feed nip roller 9 is pressed against the infeed roller 8 side by a spring (not shown). .

  The web W that has passed between the in-feed roller 8 and the feed nip roller 9 is guided to the first dancer unit 17. The first dancer unit 17 includes a first dancer roller 11 that is rotatable and a first movable frame 12. The first dancer unit 17 is suspended by the web W.

  The first dancer unit 17 is movable along the gravity direction A. First dancer unit position detecting means (not shown) for detecting the position of the first dancer unit 17 is provided, and the drive source of the infeed roller 8 is determined according to the detection signal of the unit position detecting means. Can be adjusted to adjust the position of the first dancer unit 17.

  The web W that has passed through the first dancer unit 17 has a surface treatment liquid application means 13f for applying the treatment liquid 22 to the front surface side thereof, and a back treatment liquid application means 13r for applying the treatment liquid 22 to the back surface side of the web W. , The processing liquid 22 is applied to both sides of the web W. Details of the treatment liquid application unit 13 (13f, 13r) will be described later.

  The web W that has passed through the back surface treatment liquid coating unit 13r passes between the outfeed roller 14 and the feed nip roller 9 that are rotated by a drive source (not shown) such as a motor. Although not shown, a plurality of feed nip rollers 9 are arranged opposite to each other along the axial direction of the outfeed roller 14, and each feed nip roller 9 is pressed against the outfeed roller 14 side by a spring (not shown). .

  The web W that has passed between the outfeed roller 14 and the feed nip roller 9 is wound in a W shape over the second dancer rollers 15a and 15b that are rotatable and the guide roller 1 that is disposed between the dancer rollers 15a and 15b. It is hung.

  The two dancer rollers 15a and 15b are rotatably attached to the second movable frame 16 via bearings (not shown) provided at the roller ends, respectively, to constitute a second dancer unit 18. . The second dancer unit 18 is also suspended by the web W.

  The second dancer unit 18 is also movable along the gravity direction A. Second dancer unit position detection means (not shown) for detecting the position of the second dancer unit 18 is provided, and the drive source of the outfeed roller 14 is determined in accordance with a detection signal from the unit position detection means. By controlling the rotation, the position of the second dancer unit 18 can be adjusted.

FIG. 3 is a schematic configuration diagram of the treatment liquid coating unit 13.
The processing liquid 22 stored (accommodated) in the cartridge 21 is sucked up by a pump 23 which is a liquid-feeding means of the processing liquid 22 electrically driven, such as a tubing pump or a diaphragm pump. 25, and supplied to the supply pan 26.

  As the treatment liquid 22, for example, a liquid in which a water-soluble flocculant having a function of aggregating or insolubilizing a water-soluble colorant is dissolved or dispersed in water or an organic solvent is used. The electromagnetic valve 25 is an opening / closing means of the supply path 24 configured to be electrically opened and closed, such as an electromagnetic valve and a ball valve.

  The amount (liquid level position) of the processing liquid 22 supplied to the supply pan 26 is monitored by the liquid level detection sensor 27. When the level is below a certain level, the electromagnetic valve 25 is opened and the processing liquid 22 is discharged from the cartridge 21 by the pump 23. Is sucked up and supplied to a predetermined liquid amount (liquid level position). When the liquid level detection sensor 27 detects that the liquid volume has reached a predetermined level, the electromagnetic valve 25 is closed and the pump 23 is stopped, so that the liquid volume in the supply pan 26 is kept constant. As described above, the electromagnetic valve 25 is opened only when the treatment liquid 22 is supplied, and the operation time is short. Therefore, when a normally closed type that closes the valve except when energized is used, the power consumption of the electromagnetic valve 25 can be suppressed.

  The processing liquid 22 stored in the supply pan 26 is pumped up by rotation of a squeeze roller 29 driven by a squeeze roller motor 28. As shown in this figure, the lower half of the squeeze roller 29 is immersed in the processing liquid 22. If the squeeze roller 29 is made of a grooved surface such as an anonyx roller or a wire bar, the squeeze roller 29 is less affected by the viscosity of the processing liquid 22 and the printing speed at the time of pumping. Easy to control.

  The treatment liquid 22 pumped up by the squeeze roller 29 is scraped off by the metering blade 30 and is carried to the nip portion with the application roller 31. The material of the metering blade 30 may be a metal such as stainless steel, plastic, rubber, or the like, but a plastic material is preferable from the viewpoint of wear of the squeeze roller 29, a function of scraping off excess liquid, and life.

  The processing liquid 22 conveyed to the nip portion is transferred to the coating roller 31 in a thin film shape while being uniformly stretched in the axial direction between the coating roller 31 and the squeeze roller 29. The coating roller 31 has a peripheral surface covered with an elastic body such as rubber, and is driven by a motor 32 via a one-way clutch 38.

  The processing liquid 22 applied to the application roller 31 is transferred to the web W by being nipped between the pressure roller 33 and the application roller 31. The pressure roller 33 is rotatably supported at a substantially center of the swingable arm 34 via a bearing (not shown), and rotates in accordance with the web W that is transported and moved.

  A tension spring 36 is connected to the end of the arm 34 opposite to the swing center 35. The other end of the tension spring 36 is connected to a frame (not shown), and the pressure roller 33 is pressed against the application roller 31 by the lever principle. An eccentric cam 37 provided between the pressure roller 33 and the tension spring 36 is in contact with the arm 34, and when the treatment liquid 22 is not applied, the eccentric cam 37 rotates to resist the elasticity of the tension spring 36. Thus, the pressure roller 33 can be moved away from the application roller 31.

  An opening is provided in a portion where the pressure roller 33 on the upper side of the supply pan 26 enters and retracts, and a shutter 39 for suppressing evaporation of the processing liquid 22 is provided in the opening so as to be openable and closable. . When the pressure roller 33 contacts the application roller 31, the shutter 39 is open.

The application roller 31 is cleaned by the cleaner blade 40 after the treatment liquid 22 is transferred to the web W.
On the downstream side of the coating unit 13 in the web conveyance direction, a conveyance roller 42 driven by a conveyance roller motor 41 and a guide roller 1 are provided opposite to the conveyance roller 42. The web W is pulled by the conveyance roller 42 and the guide roller 1 as the conveyance roller motor 41 is driven, and the conveyance speed of the web W is controlled by the rotation speed (linear velocity) of the conveyance roller 42. The conveyance speed of the web W is determined when the pressure roller 33 is moved by the eccentric cam 37 and the web W is sandwiched and pressed against the application roller 31.

  In the image forming system shown in FIG. 1, the processing liquid coating apparatus 101 and the ink jet printer 102 are separated. However, as shown in FIG. 3, ink jet recording is performed on the downstream side of the coating roller of the processing liquid coating apparatus 101 (processing liquid coating means 13). After providing the head 43 and applying the treatment liquid 22 on the web W by the application roller 31, an image is formed on the web W by the inkjet recording head 43 in the treatment liquid application apparatus 101 (treatment liquid application means 13). Is also possible.

  FIG. 4 is a characteristic drawing of the processing liquid pumped by the squeeze roller 29 shown in FIG. 3, wherein the horizontal axis indicates the rotational speed (linear velocity) (N) of the squeeze roller 29 and the vertical axis indicates the pumping amount of the processing liquid 22 ( M). A hatched area in the figure indicates a stable application area of the treatment liquid 22.

  As shown in this figure, the rotational speed (N) of the squeeze roller 29 and the pumping amount (M) of the processing liquid 22 are substantially proportional, and the web W is being conveyed at a predetermined speed (stable By stabilizing the rotational speed of the squeeze roller 29 above the rotational speed Na, it becomes possible to pump up a predetermined amount of the processing liquid 22 and pump up the processing liquid 22 necessary for coating on the coating roller 31. become.

The stable application region of the treatment liquid 22 is a region where the rotation speed of the squeeze roller 29 reaches the rotation speed of the rotation speed of the application roller 31 = the conveyance speed of the web W or higher.
However, the squeeze roller 29 supplies the treatment liquid 22 by nipping the application roller 31, while the application roller 31 is configured to nip and transport the web W by the pressure of the pressure roller 33. The stable application region cannot be set to a speed higher than the conveying speed of the application roller 31 and the web W. In order to set a speed higher than the conveying speed of the coating roller 31 and the web W, it is necessary to provide a gap between the squeeze roller 29 and the coating roller 31, which is not possible in practice.

  The speed Na of the squeeze roller 29 is set to the speed Na of the squeeze roller 29 = the transport speed Va of the web W during continuous transport. In addition, the speed Na of the squeeze roller 29 is set to a slightly lower speed (about 1 to 2%) than the web W conveyance speed Va as long as the supply of the processing liquid 22 due to the speed Na of the squeeze roller 29 does not occur. Is also possible.

  For example, when the speed Na of the squeeze roller 29 is too high than the conveyance speed Va of the web W, the coating roller 31 that rotates at the same speed as the squeeze roller 29 pulls the web W at a speed difference of (Na−Va). Since it is transported, the amount of the processing liquid supplied from the coating roller 31 becomes excessive, the web W after passing through the nip portion between the coating roller 31 and the pressure roller 33 is loosened, and the web W is poorly transported. There are problems such as waking up.

  On the other hand, if the speed Na of the squeeze roller 29 is too slower than the transport speed Va of the web W, the web W is transported while pulling the coating roller 31 at a speed difference of (Va−Na). There is a problem that the processing liquid supply from the roller 31 is insufficient.

  For this reason, the speed Na of the squeeze roller 29 is set to the speed Na of the squeeze roller 29 = the transport speed Va of the web W during continuous transport. Further, the speed Na of the squeeze roller 29 is set to a speed slightly lower than the web W conveyance speed Va (about 1 to 2%) as long as supply of the treatment liquid 22 due to the speed Na of the squeeze roller 29 does not occur.

  When the rotation of the squeeze roller 29 is increased almost simultaneously with the start of the conveyance of the web W (conventional method), the application by the application roller 31 starts before the squeeze roller 29 pumps up a stable application amount. Application of the treatment liquid 22 started in an insufficient amount, which was a cause of uneven application.

  Accordingly, the squeeze roller 29 reaches a certain rotational speed or more, the pump is pumped up by a predetermined amount, and the surplus portion is scraped off by the metering blade 30, so that a necessary fixed amount of the processing liquid 22 is placed on the coating roller 31. It becomes possible to secure.

  FIG. 5 is a control block diagram of the processing liquid coating apparatus. As shown in the figure, the squeeze roller motor 28 for rotating the squeeze roller 29 is connected to a squeeze roller pulse encoder 44 and a squeeze roller motor driver 45 for detecting the linear velocity of the squeeze roller motor 28. A coating roller motor 32 for rotating the coating roller 31 is connected to a coating roller pulse encoder 46 and a coating roller motor driver 47 for detecting the linear velocity of the coating roller motor 32.

  The eccentric cam motor 48 for rotating the eccentric cam 37 for moving the pressure roller 33 includes an eccentric cam pulse encoder 49 and an eccentric cam motor driver 50 for detecting the rotation angle thereof. It is connected. The conveyance roller motor 41 that rotates the conveyance roller 42 that conveys the web W is connected to a conveyance roller pulse encoder 51 and a conveyance roller motor driver 52 that detect the linear velocity of the conveyance roller motor 41.

  As the squeeze roller motor 28, the application roller motor 32, the eccentric cam motor 48, and the conveyance roller motor 41, pulse motors capable of precisely controlling rotation are used.

  Detection signals from the squeeze roller pulse encoder 44, application roller pulse encoder 46, eccentric cam pulse encoder 49, and transport roller pulse encoder 51 are input to the application device controller 53. The squeeze roller motor driver 45, the application roller motor driver 47, the eccentric cam motor driver 50, and the conveyance roller motor driver 52 are rotationally controlled by a motor control signal output from the application device controller 53. The coating device controller 53 is connected to the host controller 104 described above.

  Further, the application device controller 53 stores in advance a squeeze roller 29 capable of supplying a processing liquid amount necessary for web application, a rotation speed Na of the application roller 31, and the like.

  6 shows the relationship between the conveyance speed (linear velocity) V of the web W and time T (FIG. 6A), and the relationship between the rotational speed (linear velocity) N of the squeeze roller 29 and time T (FIG. 6B). FIG. FIG. 7 is a flowchart for explaining the rotation control of the squeeze roller 29 and the application roller 31 and the web W conveyance control.

  In FIG. 7, in step (hereinafter abbreviated as S) 1, when the coating apparatus controller 53 receives a print start signal from the host controller 104 (see timing T2 in FIG. 6), the coating apparatus controller 53 is a squeeze roller motor. A drive signal is output to the driver 45 and the application roller motor driver 47, and the rotation of the squeeze roller 29 and the application roller 31 is simultaneously started by the squeeze roller motor 28 and the application roller motor 32.

By this rotation, pulse signals are respectively input from the squeeze roller pulse encoder 44 and the coating roller pulse encoder 46 to the coating device controller 53, and the rotational speed control of the squeeze roller 29 and the coating roller 31 is started in S2. In addition,
At this time, the pressure roller 33 is not moved to the application roller 31 side, is in a separated state, and the conveyance roller 42 is not rotated, so that the web W remains separated from the application roller 31 and stopped. Is in a state.
In FIG. 7, since the description is complicated, the squeeze roller 29 is shown as a representative, and the application roller 31 is not shown.

  The squeeze roller 29 (application roller 31) increases the rotation speed toward the rotation speed Na at which stable application is possible (see FIG. 6B), and whether or not the rotation speed Na set in advance in S3 has been reached. Is monitored. When the coating device controller 53 confirms that the rotational speed of the squeeze roller 29 (coating roller 31) has reached the rotational speed Na (YES in S3), the coating device controller 53 is used for the eccentric cam at timing T3 (see FIG. 6). A drive signal is output to the motor driver 50 and the conveyance roller motor driver 52, and the eccentric cam 37 and the conveyance roller 42 are rotated by the eccentric cam motor 48 and the conveyance roller motor 48.

  By this rotation, pulse signals are respectively input from the eccentric cam pulse encoder 49 and the conveyance roller pulse encoder 51 to the coating device controller 53, and the rotation control of the eccentric cam motor 48 and the conveyance roller motor 48 is performed. . When the eccentric cam 37 rotates by a predetermined angle, the pressure roller 33 is moved and pressed against the application roller 31, and the web W is sandwiched between the application roller 31 and the pressure roller 33 to convey the web W. Is started (S4) (see timing T3 in FIG. 6).

  When the conveyance speed of the web W reaches Va, the web W is in a stable and continuous conveyance state (S5). At this time, the squeeze roller 29 and the application roller 31 are already capable of supplying a processing liquid amount necessary for web application. Since the rotation speed Na is maintained (see FIGS. 6A and 6B), a predetermined amount of the processing liquid 22 can be stably applied onto the web W by the squeeze roller 29 and the application roller 31. .

  Further, in the stop operation of the web W or the like, when the coating device controller 53 receives the web W conveyance stop signal from the host controller 104 in S6 (see timing T0 in FIG. 6), the coating device controller 53 performs the eccentric cam motor. A drive signal is output to the driver 50 and rotation of the eccentric cam 37 is started via the eccentric cam motor 48, and a deceleration signal is output to the conveyance roller motor driver 52 via the conveyance roller motor 48. The rotation of the conveying roller 42 is decelerated.

The rotation of the eccentric cam 37 causes the pressure roller 33 to move away from the application roller 31, the state where the web W is held between the application roller 31 and the pressure roller 33 is released, and the conveyance speed of the web W is reduced. The pulse signal from the conveyance roller pulse encoder 51 is input to the coating apparatus controller 53, and whether or not the conveyance speed V of the web W becomes 0 is monitored by the coating apparatus controller 53 (S7).
In this state, the squeeze roller 29 and the application roller 31 maintain rotation at the set rotation speed Na.

  When it is confirmed by the apparatus controller 53 that the conveyance speed V of the web W has become 0, that is, the pulse signal from the conveyance roller pulse encoder 51 cannot be received (YES in S7), at timing T1 shown in FIG. Stop control of the squeeze roller 29 and the application roller 31 is executed (S8).

  Specifically, the apparatus controller 53 outputs a deceleration signal to the squeeze roller motor driver 45 and the application roller motor driver 47, and the squeeze roller motor 28 and the application roller motor 32 rotate the squeeze roller 29 and the application roller 31. Reduce the speed N.

  At this time, as shown in FIGS. 6A and 6B, since the conveyance of the web W is stopped (conveying speed V = 0), the processing liquid is generated by the decrease in the rotational speed of the squeeze roller 29 and the coating roller 31. It is possible to reduce unevenness in application to the web W due to a reduction in the pumping amount of 22.

  FIG. 8 is a timing chart showing the relationship between the rotational speed (N) and time (T) of a conventional squeeze roller. As shown in the figure, in the conventional method, the linear velocity of the squeeze roller is also in the acceleration stage in the acceleration region of the web conveyance speed (after timing T3), so that the amount of processing liquid supplied from the squeeze roller to the application roller is insufficient. Occurs, and coating unevenness occurs due to insufficient supply of processing liquid to the web.

  In the present invention, when the linear speed of the squeeze roller increases to a predetermined speed and reaches the speed Na, the amount of processing liquid applied to the web is stably supplied. A stable amount of the processing liquid pumped up and supplied can be continuously supplied to the web while rotating at the same linear speed as the web conveyance speed.

  In the above-described embodiment, the conveyance roller is used as the conveyance unit for the recording medium. However, for example, other conveyance unit such as a conveyance belt may be used.

13: Treatment liquid application means,
13f: surface treatment liquid application means,
13r: backside treatment liquid coating means,
22: Treatment liquid
26: supply bread,
28: Motor for squeeze roller,
29: Squeeze roller,
31: Application roller
32: Motor for application roller,
33: pressure roller,
41: Conveyor roller motor,
42: conveying roller,
43: inkjet recording head,
44: Pulse encoder for squeeze roller,
45: Motor driver for squeeze roller,
46: Pulse encoder for application roller,
47: Motor driver for application roller,
48: Eccentric cam motor,
49: Eccentric cam pulse encoder,
50: Motor driver for eccentric cam,
51: Pulse encoder for application roller,
52: Motor driver for application roller,
53: Coating device controller,
101: Treatment liquid coating apparatus,
102: Inkjet printer,
W: Web.

JP 7-156538 A JP 2011-194619 A

Claims (4)

A recording medium conveying means for conveying the recording medium;
A supply pan for retaining the processing liquid;
A squeeze roller that pumps up the processing liquid in the supply pan;
An application roller for applying the treatment liquid supplied from the squeeze roller to the recording medium;
A pressure roller that presses the recording medium toward the application roller when the treatment liquid is applied to the recording medium, and sandwiches the recording medium with the application roller;
In a processing liquid coating apparatus provided with a controller for controlling each operation of the recording medium conveying means, squeeze roller, coating roller and pressure roller,
Squeeze roller speed detecting means for detecting the linear speed of the squeeze roller;
An application roller speed detecting means for detecting the linear speed of the application roller is provided,
The controller is
A linear velocity Na capable of supplying a processing liquid amount necessary for the recording medium application is stored in advance;
When the linear speed of the squeeze roller detected by the speed detection means for squeeze roller and the linear speed of the application roller detected by the speed detection means for application roller reach the linear speed Na stored together, A processing liquid coating apparatus, wherein the pressure roller is pressed toward the coating roller, and the recording medium transporting unit is controlled to start transporting the recording medium. The treatment liquid coating apparatus according to claim 1,
The processing liquid coating apparatus characterized in that a linear velocity Na between the squeeze roller and the coating roller immediately before the start of conveyance of the recording medium is maintained constant at the linear velocity Na during the conveyance of the recording medium by the controller. . In the processing liquid coating apparatus according to claim 1 or 2,
The controller is
A processing liquid coating apparatus, wherein after the conveyance of the recording medium is stopped, the linear velocity of the squeeze roller and the coating roller is lowered from the linear velocity Na to stop operation. Image forming means for forming an image by ejecting ink droplets from an inkjet recording head onto a recording medium to be conveyed;
In an image forming system provided with a processing liquid coating unit disposed on the recording medium carrying direction upstream side of the image forming unit and coating a processing liquid on the recording medium,
4. The image forming system according to claim 1, wherein the processing liquid coating unit is the processing liquid coating apparatus according to any one of claims 1 to 3.

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