Patent Publication Number: US-2022236678-A1

Title: Application device and image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2021-008879, filed on Jan. 22, 2021, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     Aspects of the present disclosure relate to an application device and an image forming apparatus. 
     Description of the Related Art 
     There is known an image forming apparatus that applies liquid ink to a sheet medium to form an image. Before the liquid ink is applied to the sheet medium, an application device may apply treatment liquid having an effect of aggregating the liquid ink to the sheet medium. 
     SUMMARY 
     Embodiments of the present disclosure describe an improved application device that includes an application roller to apply a treatment liquid to a sheet medium and multiple conveyance roller pairs to convey the sheet medium from an upstream side to a downstream side of the application roller. The multiple conveyance roller pairs define a conveyance path of the sheet medium and include a downstream conveyance roller pair adjacent to the application roller on the downstream side along the conveyance path. The downstream conveyance roller pair includes two rollers having a length equal to or longer than a width of the sheet medium and a nip force applying member that applies a nip force to one of the two rollers to nip the sheet medium with the two rollers in a width direction of the sheet medium. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is a schematic view illustrating an example of a printer as embodiments of an image forming apparatus according to the present disclosure; 
         FIG. 2  is a schematic view illustrating a part of an application device according to embodiments of the present disclosure; 
         FIG. 3  is a schematic view illustrating a configuration of a downstream conveyance roller pair according to a first embodiment of the present disclosure; 
         FIG. 4  is a schematic view illustrating a configuration of a downstream conveyance roller pair according to a second embodiment of the present disclosure; 
         FIG. 5  is a block diagram illustrating a control configuration of the downstream conveyance roller pair according to the second embodiment; 
         FIG. 6  is a flowchart illustrating a control flow of the downstream conveyance roller pair according to the second embodiment; 
         FIG. 7  is a control table for the downstream conveyance roller pair according to the second embodiment; 
         FIG. 8  is a schematic view illustrating a configuration of a downstream conveyance roller pair according to a third embodiment of the present disclosure; 
         FIG. 9  is a block diagram illustrating a control configuration of the downstream conveyance roller pair according to the third embodiment; 
         FIG. 10  is a flowchart illustrating a control flow of the downstream conveyance roller pair according to the third embodiment; 
         FIG. 11  is a control table for the downstream conveyance roller pair according to the third embodiment; 
         FIG. 12  is a schematic view illustrating a configuration of a downstream conveyance roller pair according to a fourth embodiment of the present disclosure; 
         FIG. 13  is a block diagram illustrating a control configuration of the downstream conveyance roller pair according to the fourth embodiment; 
         FIG. 14  is a flowchart illustrating a control flow of the downstream conveyance roller pair according to the fourth embodiment; and 
         FIG. 15  is a control table for the downstream conveyance roller pair according to the fourth embodiment. 
     
    
    
     The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. In addition, identical or similar reference numerals designate identical or similar components throughout the several views. 
     DETAILED DESCRIPTION 
     In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that have the same function, operate in a similar manner, and achieve a similar result. 
     As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Hereinafter, embodiments of the present disclosure are described with reference to the drawings.  FIG. 1  is a schematic view illustrating an overall configuration of a printer  1000  as embodiments of an image forming apparatus according to the present disclosure. The printer  1000  is, for example, an inkjet printer. 
       FIG. 1  illustrates the inkjet printer  1000  that discharges liquid ink onto a sheet P to form an image. The sheet P is an example of a sheet medium having a sheet shape. The printer  1000  includes a loading device  100 , an application device  500 , an image forming device  200 , a drying device  300 , and an ejection device  400 . The application device  500  corresponds to embodiments of an application device according to the present disclosure. 
     The loading device  100  includes a sheet loading tray  101  on which a plurality of sheets P is stacked, a feeder  102  to separate and feed the sheets P one by one from the sheet loading tray  101 . Any feeder having a function of separating and conveying the sheet P can be used as the feeder  102 , such as a device using rollers or a device using air suction. The feeder  102  feeds the sheet P from the sheet loading tray  101  to the application device  500 . 
     The application device  500  includes an application unit  600 , multiple upstream conveyance roller pairs  510 , multiple downstream conveyance roller pairs  520 , a controller  800  as circuitry, and a liquid supply unit  700 . The application unit  600  applies treatment liquid to the sheet P. The multiple upstream conveyance roller pairs  510  are disposed upstream from the application unit  600  and serves as conveyors to convey the sheet P to the application unit  600 . The multiple downstream conveyance roller pairs  520  are disposed downstream from the application unit  600  and serves as conveyors to convey the sheet P to the image forming device  200 . The liquid supply unit  700  supplies the treatment liquid to the application unit  600 . The feeder  102  coveys the sheet P to the application device  500 , and the multiple upstream conveyance roller pairs  510  convey the sheet P to the application unit  600 . The application unit  600  applies the treatment liquid to the sheet P. The multiple downstream conveyance roller pairs  520  forward the sheet P to which the treatment liquid has been applied to the image forming device  200 . 
     The image forming device  200  includes a registration roller pair  201 , a sheet conveyor  202 , a liquid discharger  205 , an upstream transfer cylinder  206 , and a downstream transfer cylinder  207 . After the sheet P fed from the application device  500  reaches the registration roller pair  201 , the registration roller pair  201  feeds the sheet P to the sheet conveyor  202  at a predetermined timing. 
     The sheet conveyor  202  includes a drum  203  and a suction device  204 . The drum  203  rotates while bearing the sheet P on an outer circumferential surface thereof. The suction device  204  generates a suction force on the outer circumferential surface of the drum  203  to bear the sheet P. With this configuration, the sheet P is conveyed while being sucked to the outer circumferential surface of the drum  203  and passes through the liquid discharger  205 . 
     The upstream transfer cylinder  206  is disposed upstream from the drum  203 . The upstream transfer cylinder  206  receives the sheet P fed from the registration roller pair  201  and transfers the sheet P to the drum  203 . The downstream transfer cylinder  207  is disposed downstream from the drum  203 . The downstream transfer cylinder  207  receives the sheet P conveyed by the drum  203  and transfers the sheet P to the drying device  300 . 
     The registration roller pair  201  feeds the sheet P to the upstream transfer cylinder  206  at a predetermined timing, and a gripper of the upstream transfer cylinder  206  grips the leading end of the sheet P. The upstream transfer cylinder  206  rotates while gripping the sheet P to convey the sheet P to a position facing the drum  203 , and transfers the sheet P to the drum  203 . 
     A gripper is also provided on the surface of the drum  203 . The drum  203  receives the sheet P gripped and conveyed by the upstream transfer cylinder  206  and grips the sheet P with the gripper. The drum  203  has a plurality of suction holes dispersedly on the surface thereof, and the suction device  204  generates suction airflows directed inward from desired suction holes of the drum  203 . The gripper of the drum  203  grips the leading end of the sheet P transferred from the upstream transfer cylinder  206 , and the suction device  204  sucks the sheet P on the drum  203  with the suction airflows. As the drum  203  rotates, the sheet P is conveyed. 
     The liquid discharger  205  includes discharge units  208   a  to  208   f  that discharge and apply liquids of different colors toward the sheet P which is borne and conveyed by the drum  203 . Hereinafter, the discharge units  208   a  to  208   f  are also collectively referred to as “discharge units  208 ,” and one of the discharge units  208   a  to  208   f  is referred to as a “discharge unit  208 ” unless distinguished. For example, the discharge unit  208   a  discharges liquid of black (K), the discharge unit  208   b  discharges liquid of cyan (C), the discharge unit  208   c  discharges liquid of magenta (M), and the discharge unit  208   d  discharges liquid of yellow (Y). 
     Further, the discharge units  208   e  and  208   f  are used to discharge the liquid of any one of Y, M, C, and K or liquid of spot color such as white, gold, or silver. Furthermore, a discharge unit  208  that discharges treatment liquid such as surface coating liquid may be provided. The discharge unit  208  is a full line head including a plurality of liquid discharge heads. Each liquid discharge head includes nozzle rows including a plurality of nozzles. 
     A discharge operation of each of the discharge units  208  of the liquid discharger  205  is controlled by a drive signal corresponding to image formation data for image forming process. When the sheet P borne on the drum  203  passes through a region facing the liquid discharger  205 , the discharge units  208  perform the discharge operation to discharge the respective color liquids to the sheet P. By this discharge operation, an image corresponding to the image formation data is printed on the sheet P. 
     That is, liquid is applied to the sheet P by the liquid discharger  205  in the image forming process. The sheet P to which the liquid has been applied is delivered from the surface of the drum  203  to the downstream transfer cylinder  207 . Similarly, the downstream transfer cylinder  207  includes a gripper on the surface thereof to grip the leading end of the sheet P. After released from the gripper of the drum  203 , the leading end of the sheet P is gripped by the gripper of the downstream transfer cylinder  207 , thereby transferring the sheet P from the drum  203  to the downstream transfer cylinder  207 . Then, the sheet P is fed to the drying device  300  via the circumferential surface of the downstream transfer cylinder  207  as the downstream transfer cylinder  207  rotates. 
     The drying device  300  includes a suction conveyor  301  and a dryer  302 . The suction conveyor  301  conveys the sheet P while sucking the sheet P transferred from the downstream transfer cylinder  207  of the image forming device  200 . The dryer  302  dries the liquid on the sheet P conveyed by the suction conveyor  301 . 
     The ejection device  400  includes an output tray  401  on which a plurality of sheets P is stacked. The sheets P conveyed from the drying device  300  are sequentially stacked and held on the output tray  401 . 
     Next, a description is given of the application device  500  according to a first embodiment of the present disclosure.  FIG. 2  is a schematic view illustrating an overall configuration of an application unit  600  included in the application device  500 . The application unit  600  is a part of the application device  500  and includes a transfer roller  601 , an application roller  604 , a metering roller  650 , and a draw-up roller  608  as illustrated in FIG.  2 . 
     The transfer roller  601  is rotatably supported at one end of an arm  602 . A spring  603  is coupled to the other end of the arm  602 . The arm  602  is supported by an arm rotation shaft  605  at an intermediate position of the arm  602  and swingable around the arm rotation shaft  605  as a rotation center. The spring  603  pulls the arm  602  by a tensile force so as to swing the arm  602  around the arm rotation shaft  605 , thereby pressing the transfer roller  601  against the application roller  604 . 
     A cam  606  contacts the arm  602 . As the cam  606  rotates, the cam  606  biases the arm  602  against the tensile force of the spring  603  so that the transfer roller  601  can be moved in a direction away from the application roller  604 . A cam motor  607  is driven to rotate the cam  606 . Therefore, the cam motor  607  is controlled so as to adjust a contact force between the transfer roller  601  and the application roller  604  to adjust the amount of treatment liquid applied to the sheet P. 
     The draw-up roller  608  is elastically pressed against the metering roller  650 , and the metering roller  650  is elastically pressed against the application roller  604 . The draw-up roller  608  is rotatably supported by a side plate of the application unit  600 . Further, the draw-up roller  608  is movably supported by the side plate of the application unit  600  in a direction toward or away from the transfer roller  601 . 
     Specifically, the draw-up roller  608  is rotatably supported by the side plate of a supply liquid chamber  609  of the application unit  600 . The supply liquid chamber  609  is swingably supported by a fulcrum  613 . An arm  610  is provided on the side plate of the supply liquid chamber  609 . The arm  610  is biased by a compression spring  612  via a pin  611 . The draw-up roller  608  is pressed against the metering roller  650  by a biasing force of the compression spring  612 , and thus the metering roller  650  is elastically pressed against the application roller  604 . 
     The liquid chamber cam  614  contacts the pin  611 . As the liquid chamber cam  614  rotates, the pin  611  moves in the vertical direction. As the pin  611  moves, the degree of compression of the compression spring  612  is changed. The supply liquid chamber  609  is moved along the pin  611  in response to the biasing force generated by the degree of compression of the compression spring  612 . As a result, the nip load between the application roller  604  and the metering roller  650  and the nip load between the metering roller  650  and the draw-up roller  608  are changed. The liquid chamber cam motor  615  is driven to rotate the liquid chamber cam  614 . 
     Further, the transfer roller  601 , the application roller  604 , the metering roller  650 , and the draw-up roller  608  are coupled by gears, and rotationally driven by an application motor  616 . Alternatively, the transfer roller  601 , the application roller  604 , the metering roller  650 , and the draw-up roller  608  may be rotated by being elastically pressed against each other. 
     The supply liquid chamber  609  contains aggregation liquid  617  as treatment liquid. The draw-up roller  608  is immersed in the aggregation liquid  617 . Therefore, as the draw-up roller  608  rotates, the aggregation liquid  617  adheres to the outer circumferential surface of the draw-up roller  608  and is scooped up. A liquid level sensor  618  is attached to the supply liquid chamber  609  to detect the liquid level of the aggregation liquid  617 . The controller  800  monitors the output of the liquid level sensor  618  to adjust the position (height) at which the draw-up roller  608  is immersed in the aggregation liquid  617 . 
     As the aggregation liquid  617  is applied to the sheet P, the aggregation liquid  617  is consumed and the liquid level of the aggregation liquid  617  in the supply liquid chamber  609  is lowered. As the liquid level sensor  618  detects that the liquid level of the aggregation liquid  617  is lower than a predetermined threshold, a supply valve  703  is opened and a supply pump  702  is driven. As the supply pump  702  is driven, the aggregation liquid  617  in a supply tank  701  is fed to the supply liquid chamber  609 . Thus, the aggregation liquid  617  is replenished to be consumed for applying to the sheet P by the application roller  604 . When the liquid level reaches a predetermined level, the supply valve  703  is closed and the supply pump  702  is stopped. Thus, the liquid level of the aggregation liquid  617  in the supply liquid chamber  609  can be kept constant. 
     The aggregation liquid  617  may deteriorate over time, for example, the viscosity increases depending on the storage time. It is not preferable to use the deteriorated aggregation liquid  617  for applying to the sheet P because the deteriorated aggregation liquid  617  may not exhibit a predetermined performance to aggregate the liquid ink on an image forming surface of the sheet P. Therefore, the aggregation liquid  617  that may have deteriorated to a certain extent over time is drained from the supply liquid chamber  609  and is not used for applying to the sheet P. The liquid supply unit  700  includes a drain valve  704 , a drain pump  705 , and a waste liquid tank  706  to drain the aggregation liquid  617  from the supply liquid chamber  609 . As the drain valve  704  is opened and the drain pump  705  is driven, the aggregation liquid  617  in the supply liquid chamber  609  is drained into the waste liquid tank  706 . 
     Next, a description is given of a flow of applying the aggregation liquid  617  to the sheet P. In the application unit  600  having the above-described configuration, the aggregation liquid  617  in the supply liquid chamber  609  is scooped up as the draw-up roller  608  rotates. The aggregation liquid  617  scooped up by the draw-up roller  608  is transported to a contact position between the draw-up roller  608  and the metering roller  650 . As the aggregation liquid  617  passes through the contact position (nip), the amount of the aggregation liquid  617  is adjusted, and the adjusted aggregation liquid  617  is transferred to the surface of the metering roller  650 . 
     The aggregation liquid  617  transferred to the surface of the metering roller  650  is transported to a contact position (nip) between the metering roller  650  and the application roller  604 . As the aggregation liquid  617  passes through the contact position (nip) between the metering roller  650  and the application roller  604 , the aggregation liquid  617 , which is a thin layer, is transferred to the surface of the application roller  604 . The thin layer of the aggregation liquid  617  formed on the surface of the application roller  604  is transported to a contact position (nip) between the application roller  604  and the transfer roller  601 , comes into contact with the sheet P, and is transferred to the image forming surface of the sheet P. Thus, the aggregation liquid  617  is applied to the sheet P. 
     The upstream conveyance roller pair  510  is disposed upstream from the application roller  604  in the conveyance direction of the sheet P and feeds the sheet P to the contact position between the application roller  604  and the transfer roller  601 . An upstream guide plate pair  626  is disposed on a path from the upstream conveyance roller pair  510  to the contact position (nip) between the application roller  604  and the transfer roller  601 . The sheet P conveyed by the multiple upstream conveyance roller pairs  510  passes through the upstream guide plate pair  626  and is conveyed to the contact position between the application roller  604  and the transfer roller  601 . As the sheet P passes through the contact position between the application roller  604  and the transfer roller  601 , the aggregation liquid  617  is applied to the sheet P, and then the sheet P is conveyed downstream. In this case, the surface of the sheet P that the application roller  604  contacts is an application surface of the aggregation liquid  617 . In a downstream process, an image is formed on the application surface, that is, the image forming surface. 
     The downstream conveyance roller pair  520  is disposed downstream from the application roller  604  to convey the sheet P immediately after being coated with the aggregation liquid  617  to the downstream side. Further, a downstream guide plate pair  628  is disposed downstream from the application roller  604  to guide the sheet P to the downstream conveyance roller pair  520 . 
     As illustrated in  FIG. 2 , the multiple downstream conveyance roller pairs  520  are disposed downstream from the application roller  604  and define a conveyance path to the image forming device  200 . One of the multiple downstream conveyance roller pairs  520  that is disposed adjacent to the application roller  604  on the downstream side of the application roller  604  has a length equal to or longer than the width of the sheet P to cover the full width of the sheet P. In other words, the downstream conveyance roller pair  520  includes two rollers that nip the sheet P next to the transfer roller  601  and the application roller  604  have a contact face that can contact the full width of the sheet P. Note that all of the downstream conveyance roller pairs  520  disposed downstream from the application roller  604  may have the configuration according to each embodiment described below. 
       FIG. 3  is a schematic view of the downstream conveyance roller pair  520  as viewed in the conveyance direction of the sheet P. The downstream conveyance roller pair  520  includes the two rollers that are longer than the width of the sheet P in a width direction of the sheet P (i.e., along the X-axis) perpendicular to the conveyance direction of the sheet P (i.e., along the Y-axis). The downstream conveyance roller pair  520  covers the full width of the sheet P, and has the contact face that evenly contacts the full width of the sheet P when the sheet P is nipped. 
     As described above, the downstream conveyance roller pair  520  includes the two rollers, that is, a lower roller  521  as a drive roller and an upper roller  522  as a driven roller. Bearings  523  are disposed at both ends of each of the lower roller  521  and the upper roller  522  to rotatably support the lower roller  521  and the upper roller  522 . 
     A pulley  527  is attached to one end of the rotation shaft of the lower roller  521 . The pulley  527  is coupled to a motor pulley  525  via a belt  526 . The motor pulley  525  is attached to a rotation shaft of a conveyance motor  524 . Therefore, the rotation of the conveyance motor  524  is controlled to rotate the lower roller  521 . 
     Tension springs  531  are attached to both ends of the rotation shaft of the upper roller  522  as a driven roller. The bearing  523  that rotatably supports the upper roller  522  is held in a vertically slotted hole provided in a frame of the application device  500 . Therefore, the upper roller  522  is movable in the vertical direction by a biasing force of the tension spring  531  applied to the rotation shaft of upper roller  522 . The tension spring  531  functions as a biasing member that biases the upper roller  522  toward the lower roller  521 , and also functions as a nip force applying member that applies a force (nip force) to nip the sheet P between the upper roller  522  and the lower roller  521 . With this configuration, the sheet P is nipped by the upper roller  522  and the lower roller  521 . 
     A nip as a contact portion between the upper roller  522  and the lower roller  521  to nip the sheet P covers the full width of the sheet P. When the sheet P passes through the nip, the lower roller  521 , which is a drive roller, rotates to transmit a conveyance force to the sheet P, thereby conveying the sheet P downstream in the conveyance direction. At that time, the upper roller  522  is driven to rotate by frictional force with the sheet P. 
     The conveyance path of the sheet P is formed such that the center of the downstream conveyance roller pair  520  in the longitudinal direction and the center of the sheet P in the width direction coincide with each other. That is, the sheet P is evenly positioned in the width direction with respect to the center of the conveyance path and conveyed in the conveyance path. 
     The downstream conveyance roller pair  520  described above is in line contact with the full width of the sheet P, not in point contact, and thus transmits the conveyance force to the sheet P by line contact. Therefore, the downstream conveyance roller pair  520  conveys the sheet P while evenly contacting the sheet P. 
     That is, the downstream conveyance roller pair  520  as a conveyor evenly contacts the entire application surface, to which the aggregation liquid  617  has been applied, of the sheet P in the width direction with a suitable force by the tension spring  531  as the nip force applying member. With this configuration, the application surface can be prevented from being partially rubbed by the conveyor (i.e., the downstream conveyance roller pair  520 ). As a result, image unevenness by rubbing the application surface can be prevented. In a comparative example, a conveyor is in point contact with the sheet P to convey the sheet P and may partially rub the application surface of the sheet P, causing image unevenness. 
     The conveyance motor  524  may be any motor that can generate the conveyance force to convey the sheet P with the downstream conveyance roller pair  520 . For example, a direct current (DC) brushless motor or a stepping motor can be used as the conveyance motor  524 . Each of the lower roller  521  and the upper roller  522  includes an elastic material. Any material may be used as long as the material does not damage the sheet P when the sheet P is nipped, for example, rubber, resin, or the like may be used. In particular, the lower roller  521  as the drive roller preferably includes rubber. 
     Next, a description is given of the application device  500  according to a second embodiment of the present disclosure. The second embodiment is different from the first embodiment in the configuration of the conveyance roller pair disposed downstream from the application roller  604  included in the application device  500 . Hereinafter, different points are described in detail. 
     A downstream conveyance roller pair  520   a  according to the second embodiment is described with reference to  FIG. 4 .  FIG. 4  is a schematic view of the downstream conveyance roller pair  520   a  as viewed in the conveyance direction of the sheet P. In the following description, the same components as those of the downstream conveyance roller pair  520  described in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted. The different portions in the second embodiment are described in detail. All of the conveyance roller pairs disposed downstream from the application roller  604  may have the same configuration as that of the downstream conveyance roller pair  520   a  described below. 
     At both ends of the downstream conveyance roller pair  520   a,  a first end of the tension spring  531  is secured to the end of the rotation shaft of the upper roller  522  as a driven roller, and a second end of the tension spring  531  is secured to a plate cam  532  serving as a nip force changer. Therefore, as the plate cam  532  rotates, the position of the second end of the tension spring  531  is changed. As a result, a tensile force of the tension spring  531  is changed, thereby changing the nip force by the tension spring  531 . 
     The nip force is set by the tensile force of the tension spring  531  as the nip force applying member. The plate cam  532  as the nip force changer rotates to a predetermined rotation angle to determine the nip force. That is, the tension spring  531  and the plate cam  532  construct the nip force applying member. The rotation of the plate cam  532  may be controlled by a motor or the like. 
       FIG. 5  is a block diagram illustrating a functional configuration of a control unit that controls the nip force of the downstream conveyance roller pair  520   a  according to the present embodiment. The control unit according to the present embodiment includes the controller  800 , an operation unit  801 , a storage unit  802 , a sensor data unit  803 , a conveyance roller nip setting unit  804 , an application roller driver  805 , and a conveyance roller driver  806 . 
     The controller  800  includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. The CPU executes a predetermined control program. The ROM stores the control program. The RAM functions as a work area for arithmetic processing of the CPU. The controller  800  executes the control program to controls the operations of the other units. That is, the controller  800  comprehensively controls the entire operation of the application device  500 . 
     The operation unit  801  receives input data from an input interface such as a touch panel on an outer surface or a top surface of a housing of the application device  500 , and transmits the input data to the controller  800 . Further, the operation unit  801  functions as a notification unit to display a processing result of the controller  800  and indicate an operation state of the application device  500  to a user. The user can set sheet characteristic data indicating characteristics of the sheet P such as the brand, type, basis weight, and thickness of the sheet P in the controller  800  with the operation unit  801 . The user can also set an amount (i.e., application amount) of the aggregation liquid  617  to be applied to the sheet P in the controller  800  with the operation unit  801 . 
     Note that the function corresponding to the operation unit  801  may be implemented by a control panel of the printer  1000 . In this case, the user sets the sheet characteristic data and the application amount with the control panel of the printer  1000 , and the data set by the user is transmitted to the controller  800 . Alternatively, the user may set the data via an operation screen of an instruction terminal (for example, a computer) connected to the printer  1000 . 
     The storage unit  802  stores table data including roller nip force data. In the table data, the roller nip force data is associated with the application amount to be set for each of the sheet characteristic data (e.g., multiple sheet types).  FIG. 7  illustrates a nip force setting table  8021  as an example of the table data stored in the storage unit  802 . The nip force setting table  8021  stores a correlation between the application amount and the roller nip force data. 
     As illustrated in  FIG. 7 , the nip force setting table  8021  is an example of the table data that stores the roller nip force data in association with the sheet type and the application amount of the aggregation liquid  617 . Accordingly, the roller nip force data can be selected based on the sheet type and the application amount. A suitable application amount is measured in advance for each sheet type included in the sheet characteristic data, and the suitable application amount (a reference value of an appropriate application amount for the sheet type) corresponds to the application amount “normal.” An appropriate nip force corresponding to the application amount “normal” is defined as the roller nip force “normal.” 
     When the user sets the sheet type to a “coated sheet” and sets the application amount of the aggregation liquid  617  to “large” with the operation unit  801 , the plate cam  532  is rotated so that the downstream conveyance roller pair  520   a  applies the roller nip force corresponding to “strong.” The roller nip force “strong” is determined relative to the roller nip force “normal,” and the degree of “strong” may be determined based on a parameter defined in advance, or data for obtaining a force stronger than the roller nip force “normal” may be separately stored. 
     The sensor data unit  803  acquires output values of various sensors such as a sheet detection sensor that detects the conveyance state of the sheet P and the liquid level sensor  618  that detects the liquid level of the aggregation liquid  617 , and transmits the output values to the controller  800 . The controller  800  detects the position of the sheet P conveyed based on sensor data and controls the operations of the upstream conveyance roller pair  510 , the downstream conveyance roller pair  520   a,  the application motor  616 , and the liquid chamber cam motor  615 . 
     The conveyance roller nip setting unit  804  controls the rotation angle of the plate cam  532  based on the roller nip force data transmitted to the controller  800 , thereby setting the tensile force of the tension spring  531  that presses the upper roller  522  against the lower roller  521 . By this control, the nip force in the downstream conveyance roller pair  520   a  is set to a predetermined magnitude. The application roller driver  805  causes the application motor  616  to rotate at a predetermined rotation speed based on a command from the controller  800 . The conveyance roller driver  806  causes the conveyance motor  524  to rotate at a predetermined rotation speed based on a command from the controller  800 . Thus, the conveyance speed of the sheet P is controlled. 
     Next, a control flow in the controller  800  according to the present embodiment is described with reference to a flowchart in  FIG. 6 . First, a user of the application device  500  sets the “sheet type” with the operation unit  801  to designate the type of the sheet P. The controller  800  receives the “sheet type” from the operation unit  801  (S 601 ). Then, the user sets the “application amount” with the operation unit  801  to designate the amount of the aggregation liquid  617  to be applied to the sheet P. The controller  800  receives the “application amount” from the operation unit  801  (S 602 ). Subsequently, based on the “sheet type” and the “application amount” set by the user, the controller  800  reads the “roller nip force” stored in the nip force setting table  8021  from the storage unit  802  (S 603 ). 
     Based on the “roller nip force,” the controller  800  instructs the conveyance roller nip setting unit  804  to set the nip force of the downstream conveyance roller pair  520   a  to a predetermined value. The conveyance roller nip setting unit  804  causes the plate cam  532  to rotate and stop at the position where the instructed nip force is obtained (S 604 ). After that, the controller  800  causes the conveyance roller driver  806  to rotate the upstream conveyance roller pair  510  and the downstream conveyance roller pair  520   a  and causes the application roller driver  805  to rotate the application roller  604 , thereby conveying the sheet P (S 605 ). 
     A description is given of the control of the nip force (roller nip force) of the downstream conveyance roller pair  520   a  controlled in the above-described processing flow. For example, when the sheet P is the coated sheet, the aggregation liquid  617  is less likely to permeate into the sheet P, remains on the surface of the sheet P, and thus is more likely to be rubbed, thereby significantly affecting the change in the frictional resistance of the surface of the sheet P and also affecting the conveyance performance of the sheet P. When the application amount is set to “large,” the conveyance performance is affected particularly on the downstream side. Therefore, the roller nip force of the downstream conveyance roller pair  520   a  is set to “strong.” 
     Even when the sheet type is the “coated sheet,” the roller nip force is set to “normal” in the case of the application amount “normal” of the aggregation liquid  617 . Here, the roller nip force “normal” is designated suitable for the application amount “normal” in advance. Further, even when the sheet type is the “coated sheet,” a predetermined conveyance state can be obtained in the case of the application amount “small” of the aggregation liquid  617 . Therefore, the roller nip force is set to “weak,” which is weaker than the roller nip force “normal” designated suitable for the application amount “normal” in advance. 
     In the present embodiment, when the sheet type is a “plain sheet,” the aggregation liquid  617  is likely to permeate into the sheet P, thereby less affecting the frictional resistance of the surface of the sheet P. Therefore, in the case of the “plain sheet,” the roller nip force of the downstream conveyance roller pair  520   a  is set to “weak” regardless of the application amount. Thus, the roller nip force is set corresponding to the application amount for each of the sheet types (i.e., the characteristic of the sheet P) to keep the conveyance performance stable. 
     As described above, when the sheet P is the “coated sheet” in the application device  500 , the roller nip force on the downstream side is set to “strong” in the case of the application amount “large” of the aggregation liquid  617  to prevent slip (speed unevenness) of the sheet P during conveyance. As a result, since the slip (speed unevenness) of the sheet P is prevented, the sheet P is prevented from being rubbed by the downstream conveyance roller pair  520   a,  thereby suppressing the change in surface properties of the sheet P and preventing image unevenness due to a difference in aggregation properties of the liquid ink due to the change in the surface properties. 
     In the case of the application amount “small” of the aggregation liquid  617  even when the sheet type is the “coated sheet”, or when the sheet type is the “plain sheet,” the roller nip force is set to “weak.” Accordingly, the grip between the application surface of the sheet P and the lower roller  521  can be prevented from being excessively strong. As a result, when an external force, which disturbs the conveyance state of the sheet P, due to a roller shape, a conveyance skew, or the like is applied to the sheet P, the external force can be released in the width direction of the sheet P, thereby preventing the sheet P from wrinkling. 
     In the present embodiment, the application amount of the aggregation liquid  617  is controlled in three levels of “large,” “normal,” and “small.” However, the number of the levels is not limited to three, and for example, the application amount may be controlled in two levels of “large” and “small” or in four or more levels. The roller nip forces “strong,” “normal,” and “weak” are parameters determined based on the application amount of the aggregation liquid  617  for each of the sheet types. The application amount is a parameter that is determined based on evaluation of a result of actually applying the aggregation liquid  617  to the sheet P in advance. The application amount “normal” is the reference value. 
     As described above, with the downstream conveyance roller pair  520   a,  the roller nip force of the sheet P can be appropriately set based on the type of the sheet P and the application amount of the aggregation liquid  617 , thereby preventing the slip (speed unevenness) of the sheet P during conveyance and wrinkles of the sheet P. As a result, image unevenness can be prevented. 
     Next, a description is given of the application device  500  according to a third embodiment of the present disclosure. The third embodiment is different from the first and second embodiments in that one of the pair of rollers includes a heater that heats the sheet P to accelerate drying of the aggregation liquid  617  on the surface of the sheet P. Hereinafter, different points are described in detail. 
     A downstream conveyance roller pair  520   b  according to the third embodiment is described with reference to  FIG. 8 .  FIG. 8  is a schematic view of the downstream conveyance roller pair  520   b  as viewed in the conveyance direction of the sheet P. Also in the following description, the same components as those of the downstream conveyance roller pair  520  described in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted. The different portions in the third embodiment are described in detail. All of the conveyance roller pairs disposed downstream from the application roller  604  may have the same configuration as that of the downstream conveyance roller pair  520   b  described below. 
     The downstream conveyance roller pair  520   b  includes a roller heater  528  as a heater inside a lower roller  521   b  as a drive roller. A temperature sensor  529  that measures the temperature of surface of the lower roller  521   b  is disposed near the longitudinal center of the lower roller  521   b.  The roller heater  528  may be any types of heater, for example, a halogen heater that can adjust the temperature of the surface of the lower roller  521   b  from the inside of the lower roller  521   b.    
       FIG. 9  is a block diagram illustrating a functional configuration of a control unit that controls the temperature of the downstream conveyance roller pair  520   b  according to the present embodiment. The control unit according to the present embodiment includes a controller  800   b,  the operation unit  801 , a storage unit  802   b,  a sensor data unit  803   b,  a heater temperature setting unit  807 , the application roller driver  805 , and the conveyance roller driver  806 . The operation unit  801 , the application roller driver  805 , and the conveyance roller driver  806  have the same configurations as those described above, and thus detailed descriptions thereof are omitted. 
     The controller  800   b  includes the CPU, the ROM, the RAM, and the like. The CPU executes a predetermined control program. The ROM stores the control program. The RAM functions as the work area for arithmetic processing of the CPU. The controller  800   b  executes the control program to controls the operations of the other units. That is, the controller  800   b  comprehensively controls the entire operation of the application device  500 . 
     The storage unit  802   b  stores table data including roller temperature setting data. In the table data, the roller temperature setting data is associated with the application amount to be set for each of the sheet characteristic data (e.g., sheet types).  FIG. 11  illustrates a roller temperature setting table  8022  as an example of the table data stored in the storage unit  802   b.  The roller temperature setting table  8022  stores a correlation between the application amount and the roller temperature setting data. 
     As illustrated in  FIG. 11 , the roller temperature setting table  8022  is an example of the table data that stores the roller temperature setting data in association with the sheet type and the application amount of the aggregation liquid  617  to control the temperature of the surface of the lower roller  521   b  at a predetermined temperature. A suitable application amount is measured in advance for each sheet type included in the sheet characteristic data, and the suitable application amount (the reference value of the appropriate application amount for the sheet type) corresponds to the application amount “normal.” A roller temperature suitable for the application amount “normal” is set based on the sheet type as a reference, and the other settings related to the application amount are determined based on the reference in advance. 
     When the user sets the sheet type to the “coated sheet” and sets the application amount of the aggregation liquid  617  to “large” with the operation unit  801 , the heater temperature setting unit  807  controls the temperature of the roller heater  528  so as to maintain the surface temperature of the lower roller  521   b  at the temperature corresponding to the roller temperature “high.” 
     The sensor data unit  803   b  acquires output values of various sensors such as the temperature sensor  529  besides the sheet detection sensor that detects the conveyance state of the sheet P and the liquid level sensor  618  that detects the liquid level of the aggregation liquid  617 , and transmits the output values to the controller  800   b.  The controller  800   b  transmits the roller temperature setting data of the roller heater  528  to the heater temperature setting unit  807  based on the output value from the temperature sensor  529 . The heater temperature setting unit  807  controls the duty of the roller heater  528  based on the roller temperature setting data transmitted from the controller  800   b  so as to control the surface of the lower roller  521   b  at a predetermined temperature. 
     Next, a control flow in the controller  800   b  according to the present embodiment is described with reference to a flowchart in  FIG. 10 . First, a user of the application device  500  sets the “sheet type” with the operation unit  801  to designate the type of the sheet P. 
     The controller  800   b  receives the “sheet type” from the operation unit  801  (S 1001 ). Then, the user sets the “application amount” with the operation unit  801  to designate the amount of the aggregation liquid  617  to be applied to the sheet P. The controller  800   b  receives the “application amount” from the operation unit  801  (S 1002 ). Subsequently, based on the “sheet type” and the “application amount” set by the user, the controller  800  reads the “roller temperature” stored in the roller temperature setting table  8022  from the storage unit  802  (S 1003 ). 
     The controller  800   b  controls the heater temperature setting unit  807  based on the “roller temperature” read from the storage unit  802  so that the surface temperature of the lower roller  521   b  becomes a predetermined temperature. The heater temperature setting unit  807  controls the duty of the roller heater  528  while referring to the output value of the sensor data unit  803   b,  and controls the surface temperature of the lower roller  521   b  (S 1004 ). After that, the controller  800   b  causes the conveyance roller driver  806  to rotate the upstream conveyance roller pair  510  and the downstream conveyance roller pair  520   b  and causes the application roller driver  805  to rotate the application roller  604 , thereby conveying the sheet P (S 1005 ). 
     A description is given of the control of the temperature of the downstream conveyance roller pair  520   a  controlled in the above-described processing flow. For example, when the sheet P is the coated sheet and the application amount is large, the temperature of the lower roller  521   b  is controlled to be high. When the sheet P is the coated sheet and the application amount is normal, the temperature of the lower roller  521   b  is controlled to be low. When the sheet P is the plain sheet, or when the sheet P is the coated sheet and the application amount is small, the roller heater  528  is turned off so as to maintain the temperature of the lower roller  521   b  at a room temperature level. 
     As described above, when the sheet P is the “coated sheet” in the application device  500 , the temperature of the lower roller  521   b  is set to be high in the case of the application amount “large” of the aggregation liquid  617  to accelerate evaporation of volatile components in the aggregation liquid  617  and keep the application surface of the sheet P stable. Thus, when the downstream conveyance roller pair  520  conveys the sheet P, an adverse effect on the application surface due to contact or rubbing between the sheet P and the downstream conveyance roller pair  520  can be prevented during conveyance. 
     In the case of the application amount “normal” of the aggregation liquid  617  even when the sheet type is the “coated sheet,” the surface temperature of the lower roller  521   b  is set to be low to accelerate the evaporation of volatile components in the aggregation liquid  617  and prevent the roller heater  528  from excessively heat the sheet P. As a result, an influence due to contact or rubbing between the sheet P and the conveyance roller pair can be suppressed, and damages to the sheet P due to heating can be prevented, thereby preventing the conveyance wrinkles or conveyance failure (jam). 
     In the case of the application amount “small” of the aggregation liquid  617  even when the sheet type is the “coated sheet,” or when the sheet type P is the “plain sheet,” the roller heater  528  is turned off. In this case, the contact or rubbing between the sheet P and the downstream conveyance roller pair  520   b  does not adversely affect a quality of the application surface even without heating the sheet P. Thus, the roller heater  528  is turned off, thereby preventing the conveyance wrinkle and the conveyance failure (jam) caused by damage to the sheet P due to heating. 
     In the present embodiment, the temperature of the roller heater  528  is controlled in three levels of “high,” “low,” and “room temperature (heater off).” However, the levels are not limited to the above example, and for example, the temperature may be controlled in three levels of “high,” “medium,” and “low.” Although the application amount is divided into three levels of “large,” “normal,” and “small,” the application amount may be divided into four or more levels. 
     Next, a description is given of the application device  500  according to a fourth embodiment of the present disclosure. The fourth embodiment is a combination of the second embodiment and the third embodiment. The main configuration is described in detail below. All of the conveyance roller pairs disposed downstream from the application roller  604  may have the same configuration as that of a downstream conveyance roller pair  520   c  described below. 
     As illustrated in  FIG. 12 , the downstream conveyance roller pair  520   c  according to the fourth embodiment includes the tension springs  531  and the plate cams  532  at both ends of the upper roller  522 , which are the same as the nip force applying member included in the downstream conveyance roller pair  520   a  according to the second embodiment. Similarly to the downstream conveyance roller pair  520   b  according to the third embodiment, the lower roller  521   b  includes the roller heater  528  inside thereof, and the temperature sensor  529  that measures the surface temperature of the lower roller  521   b  is provided. 
       FIG. 13  is a block diagram illustrating a functional configuration of a control unit that controls the nip force and the temperature of the downstream conveyance roller pair  520   c  according to the present embodiment. The control unit according to the present embodiment includes a controller  800   c,  the operation unit  801 , a storage unit  802   c,  the sensor data unit  803   b,  the conveyance roller nip setting unit  804 , the application roller driver  805 , the conveyance roller driver  806 , and the heater temperature setting unit  807 . The operation unit  801 , the sensor data unit  803   b,  the conveyance roller nip setting unit  804 , the application roller driver  805 , the conveyance roller driver  806 , the heater temperature setting unit  807  have the same configurations as those described above, and thus detailed descriptions thereof are omitted. 
     The storage unit  802   c  stores table data including the roller nip force data and the roller temperature setting data. In the table data, the roller nip force data and the roller temperature setting data are associated with the application amount to be set for each of the sheet characteristic data (e.g., sheet types).  FIG. 15  illustrates a nip force and temperature setting table  8023  as an example of the table data stored in the storage unit  802   c.  The nip force and temperature setting table  8023  stores a correlation between the application amount, the roller nip force data, and the roller temperature setting data. 
     As illustrated in  FIG. 15 , the nip force and temperature setting table  8023  stores the roller nip force data to set the nip force and the roller temperature setting data to set the temperature of the roller heater  528  in association with the sheet type and the application amount of the aggregation liquid  617 . A suitable application amount is measured in advance for each sheet type included in the sheet characteristic data, and the suitable application amount (the reference value of the appropriate application amount for the sheet type) corresponds to the application amount “normal.” An appropriate nip force corresponding to the application amount “normal” is defined as the roller nip force “normal.” The roller temperature suitable for the application amount “normal” is set based on the sheet type as a reference, and the other settings related to the application amount are determined based on the reference in advance. 
     When the user sets the sheet type to the “coated sheet” and sets the application amount of the aggregation liquid  617  to “large” with the operation unit  801 , the plate cam  532  is rotated so that the downstream conveyance roller pair  520   c  applies the roller nip force corresponding to “strong.” The roller nip force “strong” is determined relative to the roller nip force “normal,” and the degree of “strong” may be determined based on a parameter defined in advance, or data for obtaining a force stronger than the roller nip force “normal” may be separately stored. 
     When the user sets the sheet type to the “coated sheet” and sets the application amount of the aggregation liquid  617  to “large,” the heater temperature setting unit  807  controls the temperature of the roller heater  528  so as to maintain the surface temperature of the lower roller  521   b  at the temperature corresponding to the roller temperature “high.” 
     Next, a control flow in the controller  800   c  according to the present embodiment is described with reference to a flowchart in  FIG. 14 . First, a user of the application device  500  sets the “sheet type” with the operation unit  801  to designate the type of the sheet P. The controller  800   c  receives the “sheet type” from the operation unit  801  (S 1401 ). Then, the user sets the “application amount” with the operation unit  801  to designate the amount of the aggregation liquid  617  to be applied to the sheet P. The controller  800   c  receives the “application amount” from the operation unit  801  (S 1402 ). Subsequently, based on the “sheet type” and the “application amount” set by the user, the controller  800   c  reads the “roller nip force” and the “roller temperature” stored in the nip force and temperature setting table  8023  from the storage unit  802   c  (S 1403 ). 
     Based on the “roller nip force,” the controller  800   c  instructs the conveyance roller nip setting unit  804  to set the nip force of the downstream conveyance roller pair  520   c  to a predetermined value. The conveyance roller nip setting unit  804  causes the plate cam  532  to rotate and stop at the position where the instructed nip force is obtained (S 1404 ). The controller  800   c  controls the heater temperature setting unit  807  based on the “roller temperature” read from the storage unit  802  so that the surface temperature of the lower roller  521   b  becomes a predetermined temperature. The heater temperature setting unit  807  controls the duty of the roller heater  528  while referring to the output value of the sensor data unit  803   b,  and controls the surface temperature of the lower roller  521   b  (S 1405 ). After that, the controller  800   c  causes the conveyance roller driver  806  to rotate the upstream conveyance roller pair  510  and the downstream conveyance roller pair  520   c  and causes the application roller driver  805  to rotate the application roller  604 , thereby conveying the sheet P (S 1406 ). 
     A description is given of the control of the nip force (roller nip force) and the temperature of the downstream conveyance roller pair  520   c  controlled in the above-described processing flow. For example, when the sheet P is the coated sheet, the aggregation liquid  617  is less likely to permeate into the sheet P, remains on the surface of the sheet P, and thus is more likely to be rubbed, thereby significantly affecting the change in the frictional resistance of the surface of the sheet P and also affecting the conveyance performance of the sheet P. When the application amount is set to “large,” the conveyance performance is affected particularly on the downstream side. Therefore, the roller nip force of the downstream conveyance roller pair  520   c  is set to “strong,” and the temperature of the lower roller  521   b  is set to be high. Even when the sheet type is the “coated sheet,” the roller nip force is set to “normal” and the surface temperature of the lower roller  521   b  is set to be low in the case of the application amount “normal” of the aggregation liquid  617 . Here, the roller nip force “normal” is designated suitable for the application amount “normal” in advance. 
     As described above, the downstream conveyance roller pair  520   c  that is controlled based on the sheet type and the application amount of the aggregation liquid  617  can prevents the slip (speed unevenness) of the sheet P and thus prevents the application surface of the sheet P from being rubbed by the lower roller  521   b,  thereby suppressing the change in surface properties of the sheet P. As a result, image unevenness due to a difference in aggregation properties of the liquid ink due to the change in the surface properties can be prevented. In addition, the evaporation of the volatile component of the aggregation liquid  617  can be accelerated and the sheet P can be prevented from being excessively heated, thereby suppressing an influence due to contact or rubbing between the sheet P and the conveyance roller pair. Further, the sheet P is not damaged by heating, thereby preventing conveyance wrinkles and conveyance failure (jam). 
     Also in the present embodiment, the temperature of the roller heater  528  is controlled in three levels of “high,” “low,” and “room temperature (heater off).” However, the levels are not limited to the above example, and for example, the temperature may be controlled in three levels of “high,” “medium,” and “low.” Although the application amount is divided into three levels of “large,” “normal,” and “small,” the application amount may be divided into four or more levels. 
     According to the first embodiment of the present disclosure described above, the conveyor (i.e., the downstream conveyance roller pair) is in line contact with a medium (sheet P) to which the treatment liquid has been applied, not in point (partially) contact. Therefore, the application surface can be prevented from being partially rubbed by the conveyor, thereby preventing image unevenness. Further, the conveyance force that is applicable to high-speed image forming process can be secured at low cost. 
     According to the second embodiment, the nip force of the downstream conveyance pair can be changed to be suitable for the type of the sheet P and the application amount (application state) of the treatment liquid, thereby preventing the slip (speed unevenness) during conveyance of the sheet P. Accordingly, image unevenness can be prevented. In the case of the coated sheet and the application amount “large,” the nip force is set to “strong” to prevent the slip (speed unevenness) during conveyance, thereby preventing image unevenness. In the case of the coated sheet and the application amount “small,” and in the case of the plain sheet, the nip force is set to “weak” to prevent the grip between the application surface of the sheet P and the lower roller  521  from being excessively strong, thereby preventing the wrinkles of the sheet P caused by the roller shape. 
     According to the third embodiment, the downstream conveyance roller pair including the heater can apply suitable heat to the sheet medium to accelerate drying of the application surface, thereby preventing the sheet medium from deforming. Accordingly, image unevenness due to contact or rubbing between the sheet medium and the conveyance roller pair can be prevented. 
     According to the fourth embodiment, in the case of the coated sheet, the temperature of the roller heater  528  is set to be higher to heat the sheet P at a suitable temperature in response to the larger application amount and set to be lower to heat the sheet P at a suitable temperature in response to smaller application amount. With such a setting, the roller heater  528  does not excessively apply heat to the sheet medium, thereby preventing the sheet medium from deforming and wrinkling due to thermal damage to the sheet medium. As a result, the slip (speed unevenness) during conveyance can be prevented, thereby preventing image unevenness. In the case of the plain sheet, since the treatment liquid permeates into the sheet medium, and the change in the frictional force of the surface of the sheet medium is small. Therefore, the temperature of the roller heater  528  can be low (set to the “room temperature”), and the roller heater  528  does not excessively apply heat to the sheet medium, thereby preventing the sheet medium from deforming and wrinkling due to thermal damage to the sheet medium and from wrinkling caused by the roller shape. 
     As described above, according to the present disclosure, the sheet medium can be conveyed downstream while evenly maintaining the treatment liquid applied thereto. 
     The present disclosure is not limited to specific embodiments described above, and numerous additional modifications and variations are possible in light of the teachings within the technical scope of the appended claims. It is therefore to be understood that, the disclosure of this patent specification may be practiced otherwise by those skilled in the art than as specifically described herein, and such, modifications, alternatives are within the technical scope of the appended claims. Such embodiments and variations thereof are included in the scope and gist of the embodiments of the present disclosure and are included in the embodiments described in claims and the equivalent scope thereof. 
     Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above. 
     Each of the functions of the described embodiments may be implemented by one or more processing circuits or circuitry. Processing circuitry includes a programmed processor, as a processor includes circuitry. A processing circuit also includes devices such as an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field programmable gate array (FPGA), and conventional circuit components arranged to perform the recited functions.