JP2012012215A - Web conveying device and image recording device mounting the web conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein it is necessary to press a decurl part with a push amount corresponding to the diameter of a roll in a reverse direction to a curvature direction of a curl while having tension on a web in order to correct the curl of the web which is a continuous recording medium, and further it is necessary to consider control due to change of the tension.SOLUTION: A web conveying device controls the tension changed in a period in acceleration from stop, a constant speed, deceleration, and up to stop in web conveying, maintains decurl effect in a constant state by making the tension applied on the decurl part always constant, and executes correction matched with a degree of the curl of the web. The web conveying device shares a conveying mechanism to be mounted on an image recording device.

Description

  The present invention relates to a web conveyance device for decurling curled wrinkles generated on a continuous recording medium, and an image recording device equipped with the web conveyance device.

  2. Description of the Related Art Conventionally, an image recording apparatus that loads a web of a continuous recording medium made of a long recording paper or film wound in a roll shape, and discharges ink to the unwound (drawn) web to record an image. is there. Or the web conveyance apparatus which unwinds the wound web and carries it in to the apparatus which performs a certain process is known. Such a web is fed into a sheet having a desired size (hereinafter, cut by a cutter mechanism provided in the conveyance mechanism of the image recording apparatus, in the web conveyance mechanism, or in the conveyance mechanism of the apparatus in which the web conveyance apparatus is mounted. Called a web).

  Since the cut web cut into the desired size was originally wound in a roll shape, a certain amount of curl may occur immediately after unwinding. Depending on the degree of curling, when the leading edge of the cut web is caught on the transport mechanism, a jam that is a transport error occurs, or when it is stored in the discharge tray, etc., it is stored in a uniform alignment due to the warp of the cut web. However, there is a situation in which the overlap varies, and it takes time and effort to remove the inconvenience.

  As an example to solve such a problem, Patent Document 1 proposes a recording apparatus with a curl correction mechanism that corrects curl of a continuous label body by a simple mechanism that does not use an electronic element such as a sensor. Has been. Specifically, when the wound continuous label body is fed out, the position where the first rotating roller that performs the decurling function comes into contact with the continuous label body as the diameter of the winding decreases, and the rotation shaft is moved. This is a technique in which a second rotating roller provided on the opposite side of the oscillating mechanism swings the label continuum in the direction opposite to the curl curve.

JP 2009-203000 A

  Usually, in order to correct the curl of the web, which is a continuous recording medium, it is necessary to press the decal part in the direction opposite to the curving direction of the curl while the web is in tension. In the technique proposed in Patent Document 1, only the pressing amount of the decurling portion, that is, the decurling angle is controlled according to the diameter of the roll-shaped continuous recording medium (hereinafter referred to as a roll). However, in reality, it is necessary to consider the control by changing the tension.

  This is because the tension of the web in the transport path that occurs when transport is started increases in proportion to the transport acceleration due to the moment of inertia in the rotation of the roll, and becomes constant when the transport speed becomes constant. On the other hand, the tension of the web in the conveyance path that occurs when the conveyance is stopped from a certain conveyance speed is caused by the moment of inertia of the roll, and the tension decreases in proportion to the acceleration during deceleration of the conveyance, that is, a negative acceleration. When the conveyance stops, the tension is lost. Thus, since the tension of the web fluctuates at the start and stop of conveyance, an appropriate decurling effect cannot be obtained unless control is performed in consideration of this fluctuation.

  In addition, since the moment of inertia of the roll described above is proportional to the mass of the roll-shaped portion, the mass decreases and the moment of inertia changes as the remaining amount of web winding of the roll decreases with use. For example, if the mass per unit volume of the web is different or the width of the web is different so that the recording paper is expressed by basis weight, that is, if different types of web are conveyed, each roll The moments of inertia are also different because the masses of the shaped parts are different. An appropriate decurling effect cannot be obtained unless control is performed in consideration of changes in tension due to changes and differences in the moment of inertia.

  Accordingly, the present invention provides a web conveying device that can obtain an appropriate decurling effect in consideration of a change in tension due to a change in or a difference in the moment of inertia of the roll depending on the type of web as a continuous recording medium or a conveying state, and suppress the occurrence of jamming. An object of the present invention is to provide an image recording apparatus equipped with this web conveyance device.

  In order to achieve the above object, a web transport device according to an embodiment of the present invention includes a holding unit that holds a roll-like continuous recording medium wound in a roll shape in a form that can be drawn out and rotated, and the continuous recording that is drawn out. Tension is applied to the continuous recording medium between the drive unit that performs the conveyance drive of the medium and the conveyance unit that controls the conveyance drive, and the holding unit to the drive unit of the conveyance path of the continuous recording medium. A load means for applying a load to the withdrawal of the roll-shaped continuous recording medium by conveyance, and the drive from the holding means in the conveyance path of the continuous recording medium to correct the curl of the continuous recording medium. A curl correction means having a decurling part to be pressed against one surface of the continuous recording medium up to a part, and a cutter means for cutting the continuous recording medium into a desired cut length; And a mass acquisition means for acquiring a mass value of the roll-shaped continuous recording medium accompanying conveyance by the driving unit, and a radius value of the roll-shaped continuous recording medium accompanying conveyance by the driving unit. Radius acquisition means, and based on the value of the mass of the roll-shaped continuous recording medium acquired by the mass acquisition means and the value of the radius of the roll-shaped continuous recording medium acquired by the radius acquisition means Web control means for controlling at least one or both of a pulling load of the roll-shaped continuous recording medium by the load means and a pressing amount of the decurling portion against the continuous recording medium by the curl correction means. .

  According to the present invention, a web transport apparatus that can suppress the occurrence of jam by obtaining an appropriate decurling effect in consideration of a change in tension due to a change in or a difference in the moment of inertia of a roll depending on the type of web that is a continuous recording medium or a transport state. And the image recording device carrying this web conveyance device can be provided.

FIG. 1 is a diagram illustrating an overall configuration of a web conveyance device mounted on an image recording apparatus that records an image on a continuous recording medium according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a sequence from the start to the stop of the transport operation. FIG. 3A schematically shows the tension at each location during acceleration when the roll diameter is φ870 mm, and FIG. 3B shows the tension at each location during deceleration with the same roll diameter. It is the figure shown typically. FIG. 4 (a) schematically shows the tension at each location during acceleration when the roll diameter is φ106 mm, and FIG. 4 (b) shows the tension at each location during deceleration at the same roll diameter. It is the figure shown typically. FIG. 5A is a diagram showing the curl correction effect on the web tension when the curl correction instruction value of the decurling portion is constant, and FIG. 5B is the curling of the decurling portion corresponding to the web tension. FIG. 5C is a diagram showing the correction instruction value, and FIG. 5C is a diagram showing the web curl state after the curl correction according to the web tension.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows the overall configuration of a web conveyance device mounted on an image recording apparatus that records an image on a continuous recording medium according to an embodiment of the present invention. In the following description, a wound continuous continuous recording medium is referred to as a web.
The image recording apparatus 100 according to this embodiment includes two drum mechanisms 17a and 17b that hold and convey a web, and two image recording units 5a and 5b that are arranged with a gap between the drum mechanisms 17a and 17b. This is a configuration provided.

  The web conveyance device 1 according to the present embodiment has, as a mechanism, an unwinding unit 3 that accommodates a web 2 such as a recording medium wound in a roll shape so that the web 2 can be unwound (drawn), and unwinds from the unwinding unit 3. The decurling unit 4 that functions as a decurling device that corrects the curl of the web 2 that has been formed, the transport driving nip roller unit 6 that transports and drives the web 2 at a predetermined speed, and the web 2 is subjected to perforation processing or the like. A cutter unit 7 that cuts into a length, a discharge mechanism 8 that discharges a sheet-like cut web 2 cut to a predetermined length toward a post-processing machine, and a plurality of drum mechanisms 17a and 17b that form a transport mechanism. And a roller.

  Further, as a drive control system in the image recording apparatus 100 and the web conveyance apparatus 1, a conveyance control unit 9 that controls the conveyance mechanism, a recording control unit 10 that controls the image recording units 5a and 5b, An integrated control unit 11 that performs reception control of an image sent from a host device (PC: personal computer or the like) 12, and a memory unit in which web information such as web shape, basis weight, and thickness recorded in advance is stored in a readable manner 20 and an operation unit 21 for performing an operator's operation, web information setting, and the like. The embodiment shown in FIG. 1 shows a configuration example in which the web conveyance device 1 is mounted on the image recording apparatus 100. The cutter unit 7, the discharge mechanism 8, and a conveyance mechanism such as a roller are combined with each other. Configuration requirements relating to image recording, for example, the drum mechanisms 17a and 17b, the image recording units 5a and 5b, the recording control unit 10, and the like are not essential, and may be a configuration example of the web conveyance device 1.

  The unwinding unit 3 is provided with a sensor 14 for detecting the winding diameter of the roll 13 obtained by winding the web 2 in a roll shape. Furthermore, in order to maintain the web 2 in the conveying path with a constant tension without slackening, a mechanical or magnetic rotary brake, or a brake of a system in which a motor is connected and reversely rotated via a clutch is incorporated.

Each of the image recording units 5a and 5b has at least four ink heads of cyan (C), magenta (M), yellow (Y), and black (K). These image recording units 5 a and 5 b are arranged and fixed in a line along the width direction of the web 2, the image recording unit 5 a extends to the front surface of the web 2, and the image recording unit 5 b is the back surface of the web 2. Recording on the web 2 enables double-sided recording of the web 2 in one transport.
The conveyance drive nip roller unit 6 gives a conveyance force to the web 2, and has a drive motor (not shown) that drives a pair of rollers arranged to face each other with the web 2 interposed therebetween.

  The perforation cutter 23 disposed on the upstream side of the cutter unit 7 includes a perforation cut roller 23a and a receiving roller 23b (including a perforation wheel in which a discontinuous cutting edge shape on a comb tooth is formed along a disc-shaped outer periphery. In the following, the perforation anvil roller) is paired, and a process such as perforation is applied in the continuous web 2 conveyance direction.

  The sheet cutter 24 disposed on the downstream side of the cutter unit 7 includes a pair of a sheet cut roller 24a and a sheet cut anvil roller 24b each having a cutting blade for cutting the continuous web 2 into a sheet shape. 2 is cut into a cut web 25 having a desired cut length. Each roller of the perforation cutter 23 and the sheet cutter 24 has a drive source.

  A pair of perforation nip roller portions 50 are provided between the perforation cutter 23 and the sheet cutter 24 in the conveyance path of the web 2. Further, a pair of sheet cut nip roller portions 51 are provided downstream of the sheet cutter 24 of the cutter unit 7. In the perforation nip roller unit 50 and the sheet cut nip roller unit 51, one of the pair of rollers has a drive source, the other has no drive source, and is driven by a roller having a drive source. .

The discharge mechanism 8 includes a discharge roller that sequentially discharges the cut web 25 to a storage tray (not shown) and subsequent devices.
The decurling unit 4 includes a pair of free rollers 15a and 15b that supports the unwound web 2 and a decurling head 16 that is disposed between the pair of free rollers 15a and 15b and acts as a curling correction member for the web 2 by moving up and down by a driving unit (not shown). Composed.

Next, operation | movement of the web conveyance apparatus 1 comprised in this way is demonstrated.
First, the web 2 wound in a roll shape on the unwinding portion 3 is rotatably mounted. Next, the conveyance control unit 9 applies a constant tension to the web 2 unwound at any winding diameter, and the rotation speed of the roll 13 detected by the sensor 14 and the conveyance drive nip roller unit from the conveyance control unit 9. The winding diameter of the roll 13 is obtained by calculation during the transport operation from the web transport speed commanded to 6. For example, the roll diameter is calculated by detecting the number of rotations per unit time by the sensor 14. This calculates the time for one roll rotation, and the roll diameter is calculated by roll diameter = conveying speed × time for one roll rotation / π. And the brake torque given to the rotating shaft suitable for the state of the roll is variably controlled. In addition, the winding diameter may be obtained by directly detecting the winding diameter of the roll with a non-contact sensor or by reading the position of a member brought into contact with the outer periphery of the roll.

  Further, the curl of the web 2 generated based on the obtained winding diameter of the roll 13 is corrected by the decurling head 16 of the decurling unit 4. Here, the degree of curling, which is the curl of the web 2, generally varies depending on the roll winding diameter. The web 2 wound on the roll having a large winding diameter has a small curl in the unwound state, and the web 2 wound on the roll having a small winding diameter has a large curl in the unwound state. That is, the curl amount of the unwound web 2 can be predicted by using the winding diameter information of the roll 13 obtained from the conveyance speed commanded by the sensor 14 and the conveyance control unit 9 described above.

  The web 2 unwound from the unwinding section 3 is applied to the free roller pair 15a, the decurling head 16 and the free roller pair 15b of the decurling section 4. The web 2 passing therethrough is wound around the decurling head 16 in the direction opposite to the roll winding direction of the unwinding portion 3 and descends, and correction (decal) is performed according to the degree of the descending.

  When the diameter of the roll 13 is large, the decurling head 16 has a small amount of contact with the web 2 (the descending distance is short) because the curl remaining on the web 2 at the time of unwinding is weak. Control and wrap. On the other hand, when the diameter of the roll 13 is small, the curl remaining on the web 2 at the time of unwinding is strong. Therefore, the amount of contact of the decurling head 16 with the web 2 is compared with the case where the diameter of the roll 13 is large. Wind in a controlled state (long descending distance). In FIG. 1, the decurling head 16 is shown in a lowered state (solid line).

  When the line head type ink jet printer is adopted for the image recording units 5a and 5b, for example, the web 2 is wound around the large-diameter drums 17a and 17b, and the web 2 is rotationally driven by applying a certain tension, thereby causing the web 2 to slip. While preventing, the driving force is transmitted to convey at a desired speed. Ink ejection timing control of the image recording units 5a and 5b arranged with a predetermined gap along the outer peripheral surfaces of the drums 17a and 17b is performed based on pulses synchronized with the conveyance speed output from the drum encoders 18a and 18b. .

  The conveyance control unit 9 counts the output pulses of the encoder 18b of the drum 17b that rotates in synchronization with the travel distance of the web 2, and the sheet of the sheet cutter 24 disposed on the downstream side of the cutter unit 7 based on this count value. The rotation timing of the cut roller 24a is controlled to cut the web 2 into a sheet (cut web) having a predetermined length.

  As described above, when the tension in the decurling unit 4 increases, the decurling correction effect increases, and when the tension decreases, the decurling correction effect decreases. Therefore, if the tension changes during the acceleration or deceleration of the conveying operation and an appropriate decurling effect cannot be obtained, the curled cut web causes a problem that the conveying mechanism after the discharging mechanism 8 causes a jam. In addition, if the tension of the transport path fluctuates during acceleration / deceleration, there is a problem that slipping occurs in the rollers in the transport system path, causing the drive motor to step out or cause fluctuations in rotation, which prevents stable travel. .

  Therefore, in this embodiment, in order to keep the tension in the decurling unit 4 constant regardless of the conveyance state, the conveyance speed information that the conveyance control unit 9 instructs the conveyance drive nip roller unit 6 and the integrated control unit 11 Based on the information of the roll 13 input in advance by the user, the tension variation generated during acceleration and deceleration is calculated, and then the brake 19 arranged in the unwinding unit 3 is controlled. For example, the brake 19 brakes the rotation of the roll shaft 32 that holds the roll 13 by braking, and controls the tension applied to the web 2.

This will be described with reference to a sequence diagram from the start to the stop of the conveying operation shown in FIG.
First, when a recording operation start command is instructed from the integrated control unit 11, the conveyance control unit 9 releases the brake 19 fixed to the shaft of the roll 13 of the unwinding unit 3 from the released state to the braking state (the brake is applied). Switch to (status). Note that a fixed brake 34 that is in a fixed state when not energized, such as when not in operation, and in a released state when energized may be provided. That is, when not in operation, the fixed brake 34 is operated to release the brake 19. On the other hand, when a recording operation start command is issued during operation, the brake 19 is once switched to the braking state and then the fixed brake 34 is released.

  In this way, by arranging two brakes in parallel and supplementing the braking state, the roll 13 can always be braked regardless of whether the device is in operation or not, if the conveyance is stopped. The brake is not completely released during non-operation, and the roll 13 can be prevented from rotating due to its own weight due to the weight unbalance to cause the web to sag, thereby improving the conveyance stability. Further, when the brake 19 is in a braking state, the tension applied to the web 2 is based on the winding diameter information of the roll 13 acquired by the control unit 22 based on the sensor 14 and the conveyance speed information in the previous image recording operation in the memory unit 20. It is set based on a value stored in a nonvolatile manner.

  At the start of unwinding, after the brake 19 is switched to the braking state, the fixed brake 34 is switched to the released state, and the perforation anvil roller 23b of the perforation cutter 23 disposed upstream of the cutter unit 7 and the rotation of the rollers of the discharge mechanism 8 are rotated. To start.

  The perforation anvil roller 23b of the perforation cutter 23 is a metal cylinder such as a cylindrical iron having a flat surface for receiving a pressing force when a perforation wheel for machining perforations is pressed against the web. Since only a small frictional force is applied to the web 2, slip driving is performed at a speed of several percent faster than the web conveyance speed, for example, 5% faster and 105%.

  The perforation cutter 23 is switched between a pressing state in which the perforation wheel is pressed against the perforation anvil roller 23b and a retracting state in which the perforation cutter 23 is not pressed. This switching is performed by a motor with a cam (not shown) provided on the perforation cut roller 23a.

  The perforation wheel is retracted so as not to be pressed against the perforation anvil roller 23b until the conveyance speed reaches a constant speed for performing the recording operation. When the web conveyance speed is 0, the perforation wheel is retracted, the perforation anvil roller 23b is slid with respect to the web 2, and the drive roller of the perforation nip roller unit 50 arranged upstream of the cut roller is conveyed from the conveyance drive nip roller unit 6. In addition, the web is conveyed by rotating at a linear speed about 5% faster, and tension is generated between the cutter unit 7 and the conveyance driving nip roller unit 6.

  Next, rotation driving of the conveyance drive nip roller unit 6 that determines the basic conveyance speed of the web is started. The rotation speed (web conveyance speed) of the conveyance drive nip roller 6 is, for example, a constant conveyance drive nip roller speed during image recording or the like: 0.638 m / s, and a conveyance drive nip roller acceleration during acceleration: 0.266 m / s. It is assumed that s ^ 2 and the conveyance drive nip roller acceleration at the time of deceleration: -0.204 m / s ^ 2, and the roll diameter is two types: a: φ870 mm and b: φ106 mm.

  As shown in FIG. 2, the integrated control unit 11 starts the rotation of the sheet cut anvil roller 24b on the downstream side of the cutter unit 7 at a speed equal to the web conveyance speed simultaneously with the rotation of the conveyance drive nip roller unit 6. The drive source of each of the perforation nip roller unit 50 and the sheet cut nip roller unit 51 arranged in a pair on the upstream side and the downstream side of the sheet cutter 24 is several percent faster than the web conveyance speed, for example, 5% faster, 105% speed. It is rotated by. A slip clutch or the like is connected between each drive roller of the perforation nip roller unit 50 and the sheet cut nip roller unit 51 and each drive source. The drive rollers of the perforation nip roller unit 50 and the sheet cut nip roller unit 51 rotate according to the web conveyance speed while obtaining a rotational force faster than the web conveyance speed from the respective drive sources via the clutch and the like. As a result, the web 2 in the cutter unit 7 is started to be conveyed so that no slack occurs while a slight constant tension is applied.

  Here, a low-speed conveyance section is provided in which the conveyance drive nip roller unit 6, the perforation nip roller unit 50, the sheet cut nip roller unit 51, and the perforation anvil roller 23b are conveyed at a constant speed sufficiently smaller than the conveyance speed during recording. This is because the web conveyance is started when the web 2 is in a slack state in the previous recording / conveying operation, and the impact when the tension is generated after the slack is removed is alleviated. After transporting the distance where the slack is eliminated and the tension is recovered, acceleration is started toward the transport speed during recording.

  At this time, if the product of the moment of inertia of the roll 13 and the web conveyance acceleration is divided by the square of the winding radius of the roll 13, the tension generated in the web 2 can be obtained. Here, the winding radius of the roll 13 is the same as the known web conveyance speed that the conveyance control unit transmits to the conveyance drive nip roller unit 6, for example, rotates coaxially with the roll 13, and is slit on the outer periphery. Can be obtained in real time for the conveying operation by dividing by the angular velocity obtained from the disk provided with a large number of pulses and the pulse period obtained by the photosensor.

  The moment of inertia in the roll 13 is obtained by combining the information on the thickness, basis weight, and width of the web 2 recorded in the memory unit 20 with the winding diameter of the roll 13 obtained above, and calculating the mass of the current roll 13. Ask. In addition, when conditions differ depending on, for example, the roll 13 to be mounted, the information on the thickness, basis weight, and width of the web 2 may be set according to the roll to be mounted. Further, the mass (weight) of the roll 13 may be obtained by a known technique. As the mass detection means, for example, the weight may be directly measured using a scale, or the pressure sensor 30 or the like may be provided, and calculation may be performed using the detection signal.

The moment of inertia of the roll 13 is obtained from these masses and radii. For example, “the moment of inertia of the roll = ½ × the roll mass × the roll winding radius squared”.
By such a detection method and the calculation method described below, the control unit 22 controls the set torque to the brake 19 so as to give a tension that is obtained by subtracting the tension generated by acceleration from the target tension of the decurling unit 4. To do.

[Brake control target value during acceleration]
The formula of brake tension: Tpc (N) is as follows.

また、各式のパラメータ及び以下の表に示す。

Moreover, it shows in the parameter of each formula, and the following tables.

  As shown in Table 1, for example, when the target tension of the web 2 in the decurling unit 4 is 20 N, and the roll 13 has a diameter of 870 mm, the inertia tension Tri generated when the roll 13 and the roll shaft 32 are accelerated (FIG. 2). Since a1) is 19.8N, if the brake tension Tpc (a2 in FIG. 2) is controlled to 0.2N, the tension at the decurling unit 4 becomes 20N.

  When the roll 13 has a diameter of 106 mm, the inertia tension Tri (b1 in FIG. 2) generated when the roll 13 and the roll shaft 32 are accelerated is 1.3 N. Therefore, the brake tension Tpc (b2 in FIG. 2) is If it controls to 18.7N, the tension | tensile_strength in the decurling part 4 will be 20N like a roll with a diameter of 870 mm.

  Thus, since the tension at the decurling unit 4 does not change during the acceleration from the stop to the constant speed, the decurling effect can be kept constant, and the curl correction state of the web 2 is also constant. The state can be maintained.

  Next, when shifting from acceleration to a constant speed, the transport speed of the transport drive nip roller unit 6 gradually approaches a constant recording speed according to a quadratic curve. That is, the conveyance acceleration, which is a time derivative of the conveyance speed, gradually approaches 0 along a linear line. The reason why the change in the conveyance speed is smoothly controlled by the quadratic curve in the vicinity of the change of the acceleration is that the disturbance of the conveyance acceleration occurs in the entire conveyance system due to the expansion and contraction of the web 2 and the bending of the conveyance roller, and the tension and the conveyance state are changed. This is to prevent instability.

 The recording control unit 11 performs recording control on the recording units 5a and 5b at a constant conveyance speed, the image data received from the host device 12 is recorded on the web 2, and the conveyance is stopped after the image recording is completed. Move to operation. Even when the conveyance deceleration operation is started, after the change in the conveyance speed is controlled by a quadratic curve, the conveyance is stopped at a constant negative acceleration.

  In order to keep the tension in the decurling unit 4 at the same tension as the constant speed even during the conveyance deceleration, the brake control is performed by the following calculation. When the conveyance is decelerated, the decal unit 4 is set so that the negative acceleration of the conveyance stop by the conveyance drive nip roller unit 6 is gradually changed with respect to the negative acceleration of the natural stop determined by the brake of the roll 13. Is controlled to a desired value. At the time of deceleration, the control unit 22 controls the set torque for the brake 19 by the calculation method described below.

[Brake control target value during deceleration]
The formula of brake tension: Tpc (N) is as follows.

また、各式のパラメータは、以下の表に示す。

The parameters of each formula are shown in the following table.

  As shown in Table 2, for example, when the target tension of the web 2 in the decurling unit 4 is 20 N, and the roll 13 has a diameter of 870 mm, the inertia tension Tri generated when the roll 13 and the roll shaft 32 are decelerated (FIG. 2). A3) in the formula is -15.2N. Further, since the inertia tension Tdi generated when the drum 17a is decelerated is -2.5N, if the brake tension Tpc (a4 in FIG. 2) is controlled to 37.7N, the tension at the decurling unit 4 becomes 20N.

  Similarly, when the diameter of the roll 13 is 106 mm, the inertia tension Tri (b3 in FIG. 2) generated when the roll 13 and the roll shaft 32 are decelerated is −1.0 N, and the inertia tension generated when the drum 17a is decelerated. Since Tdi is −2.5N, if the brake tension Tpc (b4 in FIG. 2) is controlled to 23.5N, the tension at the decurling unit 4 becomes 20N as with the 870 mm diameter roll.

  3 (a), 3 (b) and 4 (a), 4 (b) schematically show the tension obtained by the above-described calculation as the brake control, the inertia of the roll and the roll shaft, and the inertia of the drum. FIG. FIG. 3 (a) shows the time of acceleration when the roll diameter is φ870 mm, and FIG. 3 (b) shows the tension during deceleration of the same roll diameter. FIG. 4 (a) shows an acceleration when the roll diameter is φ106 mm, and FIG. 4 (b) shows a tension during deceleration at the same roll diameter. As in FIG. 2, the conveyance drive nip roller constant speed at the time of image recording or the like: 0.638 m / s, conveyance drive nip roller acceleration at acceleration: 0.266 m / s ^ 2, conveyance drive nip roller acceleration at deceleration: The condition is -0.204 m / s ^ 2.

  Here, the tension of the web 2 in the decurling unit 4 at the time of conveyance acceleration shown in FIGS. 3A and 4A does not take into account the moment of inertia of the drum 17a located downstream of the decurling unit 4, and FIG. (B) and the moment of inertia of the drum 17a are taken into account at the time of conveyance deceleration shown in FIG. 4 (b). At the time of conveyance acceleration, since the drum 17a is pulled by the web 2 and rotates with it, the moment of inertia of the drum 17a does not affect the tension of the web 2 in the decurling unit 4.

  At the time of conveyance deceleration, the pulling force to the drum 17a decreases due to the conveyance deceleration of the web 2, whereas the drum 17a tries to convey the web downstream in the web conveyance direction due to the inertia moment of the drum 17a. This is because the moment of inertia of 17 a affects the tension of the web 2 in the decurling unit 4. In order to control the tension of the decurling unit 4 to a desired value, calculation is performed including a change in tension caused by the moment of inertia when the drum 17a is decelerated during conveyance deceleration.

  In this example, the roll diameter range is from φ106 mm to φ870 mm. However, it is also possible to control a roll of a larger size by changing the values of acceleration and tension at a constant speed.

  Further, as a method for obtaining the winding radius of the roll 13, there is a configuration in which, for example, a line sensor 33 in which reflective photosensors are arranged in the roll radius direction is fixed to the unwinding part frame 31 using an optical sensor. According to this configuration, the emitted light of the sensor fixed at a location having a radius smaller than the roll radius is reflected by the roll side surface and detected by the light receiving unit, and it can be detected that the roll diameter is equal to or larger than the arrangement radius of the sensor. . On the other hand, since the emitted light of the sensor fixed at a position equal to or larger than the roll radius is not reflected by the side surface of the roll, it can be detected that the roll diameter is equal to or smaller than the arrangement radius of the sensor at the light receiving unit.

  From the above detection results, for example, an intermediate value between two radii can be obtained as the roll radius, or the maximum value of the sensor that has detected the reflected light can be obtained as the roll radius. In this case, since the detection light of the photosensor can be directly irradiated and reflected on the side surface of the roll, it can be detected, so that it is necessary for the rotation detection. The rotary type rotates coaxially with the roll 13 and has many slits on the outer periphery of the disk. A movable member such as a chopper can be omitted, and the reliability can be improved. The means for obtaining the winding radius of the roll 13 is not a photoelectric type but may be a sensor that detects displacement by mechanically contacting the probe with the outer peripheral surface of the roll.

  Further, the roll mass is obtained by combining the information on the web thickness, basis weight, and width already recorded in the memory unit 20 with the roll diameter of the roll obtained as described above, and the moment of inertia of the roll is calculated from these mass and radius. Explained how to find. Among these, the mass (weight) of the roll may be obtained directly from the pressure sensor 30 [mass acquisition means].

  For example, the pressure sensor 30 uses a piezo element whose resistance value changes according to pressure, and is fixed to the unwinding part frame 31, and the load of the roll shaft 32 inserted into the roll shaft through hole of the roll 13 is measured. Arrange to receive. As described above, if the information from the pressure sensor is used, there is no need to calculate based on the information on the web thickness, basis weight, width and the roll diameter of the roll obtained as described above. The mass of the roll can be determined.

  Further, the radius of the roll 13 may be obtained from the information on the thickness, basis weight, and width of the web 2 recorded in the memory unit 20 and the mass of the roll 13 obtained by the mass detection means such as the pressure sensor 30. Good. In the above-described configuration, the web width is recorded in the memory 20 in advance, but an optical sensor is used, for example, a line sensor in which a reflective photosensor is arranged in the web width direction, 3 or other web 2 may be provided in the conveyance path to detect the width of the web.

  As described above, according to the present embodiment, by controlling the brake of the unwinding unit from stop to acceleration, constant speed, deceleration, and stop in web conveyance, the tension on the decurling unit is always constant and does not change. Therefore, the decurling effect can be kept constant, and the web curl correction state can also be kept constant. In addition, by smoothly controlling the speed change with a quadratic curve near the acceleration change time, the tension of the decal part becomes a stable constant value without having an inflection point. As a result, it is possible to prevent the disturbance of the acceleration due to the entire conveyance system and the conveyance state from becoming unstable, and to stabilize the jam and the conveyance as well as stabilizing the decal state of the web.

  From the above, the web conveyance device mounted on the image recording apparatus of the present embodiment corresponds to a roll-like continuous recording medium having different widths, masses per unit volume, and roll radii, and roll-like at the time of acceleration / deceleration. The tension in the decurling unit can be kept constant with respect to the inertial tension fluctuation of the continuous recording medium. Further, by adjusting and controlling the pressing amount of the decurling unit against the continuous recording medium, an appropriate decurling effect can be obtained regardless of the type of the continuous recording medium and the conveying state, and jamming can be suppressed.

  Next, the web conveyance device of the second embodiment will be described with reference to FIGS. FIG. 5A is a diagram illustrating a curl correction effect on the web tension when the curl correction instruction value of the decurling unit 4 is constant, and FIG. 5B is a diagram illustrating the decurling unit 4 corresponding to the web tension. FIG. 5C is a diagram showing the web curl state after the curl correction according to the web tension.

  In the first embodiment described above, the brake 19 is controlled based on the information on the mass and radius of the roll so that the tension in the decurling unit 4 at the time of acceleration and deceleration of web conveyance is constant. In the embodiment, the decurling unit is controlled based on the tension value in the decurling unit 4 during acceleration and deceleration.

  In the decurling unit shown in FIG. 1, the curl correction effect is increased when the decurling head 16 is moved downward and the curl correction effect is decreased when the decurling head 16 is moved upward, under the condition that the web tension is constant. In general, as a characteristic when curling occurs, under the condition that the position of the decurling head is constant, as shown in FIG. 4A, when the tension is high, the curl correction effect is large, and when the tension is small, the curl correction is performed. The effect is reduced.

  Therefore, as shown in FIG. 4B, when the web tension is large, the curl correction instruction is issued in the direction of weakening the curl correction. Conversely, when the web tension is small, the curl correction instruction is issued in the direction of increasing the curl correction. As a result, the curl state of the web can be kept constant regardless of the tension as shown in FIG. 4C. It becomes possible.

  As described above, according to the present embodiment, even if the tension of the decurling unit is not always kept constant, the difference in set tension when changing to a roll paper having a different recording medium basis weight or a different width, acceleration, Even when the inertial tension fluctuation of the roll paper at the time of deceleration occurs, an appropriate decurling effect can be obtained regardless of the paper type and the conveyance state. Furthermore, even if acceleration / deceleration changes occur in the entire conveyance system due to web expansion / contraction or deflection of the conveyance roller, the web decal state is stabilized following the change, and web slip and jam are not generated. A web transport device can be provided.

  Although the first and second embodiments of the present invention have been described, the present invention is not limited to these embodiments, and various improvements and modifications can be made without departing from the scope of the present invention. Is possible. For example, some constituent elements may be deleted from the overall configuration shown in each embodiment of the present invention described above, and further different constituent elements in each embodiment may be appropriately combined.

  DESCRIPTION OF SYMBOLS 1 ... Web conveyance apparatus, 2 ... Web, 3 ... Unwinding part, 4 ... Decal part, 5a, 5b ... Image recording part, 6 ... Conveyance drive nip roller part, 7 ... Cutter part, 8 ... Discharge mechanism, 9 ... Conveyance control , 10: Recording control unit, 11: Integrated control unit, 12: Host device, 13 ... Roll, 14 ... Sensor, 15a, 15b ... Free roller pair, 16 ... Decal head, 17a, 17b ... Drum mechanism, 18a, 18b DESCRIPTION OF SYMBOLS ... Drum encoder, 19 ... Brake, 20 ... Memory part, 21 ... Operation part, 22 ... Control part, 23 ... Perforation cutter, 24 ... Sheet cutter, 25 ... Cut web, 30 ... Pressure sensor, 31 ... Unwinding part frame, 32 ... Roll shaft, 33 ... Line sensor, 34 ... Fixed brake, 50 ... Perforation nip roller, 51 ... Sheet cut nip roller 100 ... the image recording device.

Claims (11)

Holding means for pulling and holding the roll-shaped continuous recording medium wound in a roll shape in a rotatable form;
A drive unit that performs conveyance drive of the drawn continuous recording medium, and a drive unit that includes a conveyance control unit that controls conveyance drive;
Load means for applying a load to the withdrawal of the roll-shaped continuous recording medium by conveyance in order to apply tension to the continuous recording medium between the holding means and the drive unit in the conveyance path of the continuous recording medium;
In order to correct the curl of the continuous recording medium, the curl correction means having a decurling part that presses against one surface of the continuous recording medium between the holding means and the drive unit of the conveyance path of the continuous recording medium;
Cutter means for cutting the continuous recording medium into a desired cut length;
Further comprising
Mass acquisition means for acquiring a value of mass of the roll-shaped continuous recording medium accompanying conveyance by the drive unit;
Radius acquisition means for acquiring a value of a radius of the roll-shaped continuous recording medium accompanying conveyance by the drive unit;
Comprising
Based on the value of the mass of the roll-shaped continuous recording medium acquired by the mass acquisition means and the value of the radius of the roll-shaped continuous recording medium acquired by the radius acquisition means, the roll-shaped continuous by the load means Web control means for controlling at least one or both of the drawing load of the recording medium and the pressing amount of the decurling portion against the continuous recording medium by the curl correction means;
A web conveyance device characterized by comprising:   The web control means, based on the mass value of the roll-shaped continuous recording medium acquired by the mass acquisition means and the radius value of the roll-shaped continuous recording medium acquired by the radius acquisition means, 2. The web conveyance device according to claim 1, wherein a pulling load of the roll-shaped continuous recording medium by the load unit is controlled so as to keep the tension of the recording medium in a section constant.   The radius acquisition means also serves as the mass acquisition means, and in addition to the value of the radius of the roll-shaped continuous recording medium acquired by the radius acquisition means, the width of the roll-shaped recording medium and the mass per unit volume of the recording medium The web conveyance device according to claim 1, wherein a mass value of the roll-shaped continuous recording medium is acquired by the method.   The mass acquisition means also serves as the radius acquisition means, and in addition to the value of the mass of the roll-shaped continuous recording medium acquired by the mass acquisition means, the width of the roll-shaped recording medium and the mass per unit volume of the recording medium The web conveyance device according to claim 1, wherein a value of a radius of the roll-shaped continuous recording medium is acquired by the method.   The radius acquisition means has a radius detection one-dimensional sensor provided along the radial direction of the roll-shaped continuous recording medium, and detects the value of the radius of the roll-shaped continuous recording medium by the radius detection one-dimensional sensor. The web conveyance device according to any one of claims 1 to 3, wherein the web conveyance device is characterized.   The radius acquisition unit includes a rotation number detection unit that detects a rotation number of the roll-shaped continuous recording medium by conveyance, and in addition to the rotation number value detected by the rotation number detection unit, speed control of the conveyance control unit 4. The continuous web conveyance device according to claim 1, wherein a radius value of the roll-shaped continuous recording medium is calculated based on a conveyance speed of the continuous recording medium based on information. 5.   The mass acquisition means has a weight detection sensor for detecting the weight of the roll-shaped continuous recording medium, and acquires the mass of the roll-shaped continuous recording medium from the value of the weight acquired by the weight detection sensor. The web conveyance apparatus in any one of Claim 1, 2, 4.   The mass acquisition means has a width detection one-dimensional sensor for detecting the width of the roll-shaped continuous recording medium, and at least the value of the radius of the roll-shaped continuous recording medium acquired by the radius acquisition means, and the width detection primary The mass value of the roll-shaped continuous recording medium is calculated based on the mass per unit volume of the continuous recording medium in addition to the width value of the continuous recording medium detected by the original sensor. Item 5. The web conveyance device according to any one of Items 1, 2, and 4.   9. The web conveyance device according to claim 1, wherein the load unit includes a brake unit that applies a brake to a drawer of the web wound in a roll shape. Holding means for pulling and holding the roll-shaped continuous recording medium wound in a roll shape in a rotatable form;
A drive unit that performs conveyance drive of the drawn continuous recording medium, and a drive unit that includes a conveyance control unit that controls conveyance drive;
Load means for applying a load to the withdrawal of the roll-shaped continuous recording medium by conveyance in order to apply tension to the continuous recording medium between the holding means and the drive unit in the conveyance path of the continuous recording medium;
In order to correct the curl of the continuous recording medium, the curl correction means having a decurling part that presses against one surface of the continuous recording medium between the holding means and the drive unit of the conveyance path of the continuous recording medium;
Cutter means for cutting the continuous recording medium into a desired cut length;
Mass acquisition means for acquiring the value of the mass of the roll-shaped continuous recording medium accompanying conveyance by the drive unit, Radius acquisition means for acquiring the value of the radius of the roll-shaped continuous recording medium accompanying conveyance by the driving unit, Based on the value of the mass of the roll-shaped continuous recording medium acquired by the mass acquisition means and the value of the radius of the roll-shaped continuous recording medium acquired by the radius acquisition means, the load by the load means Web control means for controlling at least one or both of a drawing load of the roll-shaped continuous recording medium and a pressing amount of the decurling portion to the continuous recording medium by the curl correction means;
Image recording means for recording an image on the continuous recording medium;
An image recording apparatus comprising: The image recording apparatus includes:
The image recording apparatus according to claim 10, wherein the web conveyance apparatus according to claim 2 is mounted.

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