in accordance with the present invention , a drive unit is controlled so as to limit the position of a tension roller to a tension region in which winding of a printing paper web can be conducted in the direction such that the bending angle of the winding path that bends to the winding of the printing paper defines a more obtuse angle and thus the web bends at a less acute angle . this enables operation of a printing paper winding device that is suitable for winding even printing paper with a low resistance to bending stresses . the printing paper winding device 2 of an embodiment of the present invention is explained below with reference to fig1 to fig8 . fig1 is a schematic side view of a printer 1 and of a printing paper winding device 2 connected to the printer 1 . the printer 1 has a supply unit 4 for printing paper 3 . that paper is provided thereon , for example , with labels or tags . a detector 5 detects the position of the printing paper 3 , and particularly the labels on tags thereon . a printing unit 6 prints on the printing paper 3 . a cutting unit 7 cuts the trailing end section of the printed printing paper 3 after it has been wound up by the printing paper winding device 2 , and a printer control unit 8 controls the aforementioned units . the printing unit has a thermal head 9 and a platen roller 10 . the printing paper 3 is sandwiched between the thermal head 9 and the platen roller 10 , and the printing paper 3 is discharged and transported toward the printing paper winding device 2 by rotation of the platen roller 10 after predetermined information has been printed on the printing paper 3 . the cutting unit 7 may be driven by the printer control unit 8 to mechanically cut the printing paper 3 or it can comprise a member for cutting the end section of the printing paper 3 manually . fig2 is a perspective view of the printing paper winding device 2 . the printing paper winding device 2 has a device body 11 , a first fixed guide roller 12 for guiding and introducing the printed printing paper 3 into the printing paper winding device 2 , a movable , and particularly a swingable , tension roller 13 , a second fixed guide roller 14 for guiding the printing paper 3 from the tension roller 13 , a winding unit 15 for winding the printing paper 3 into a roll , a control unit 16 , a power source switch 17 , and a winding control unit 18 . a tension roller rotary support shaft 19 is provided at a vertical wall surface section 11 a in the device body 11 . a roller arm 20 , which can swing around the shaft 19 as an axis , can swing in both the forward or direct direction generally downstream in the web path and in the reverse direction , is mounted on the roller rotary shaft 19 . the tension roller 13 is rotatably mounted on a distal end section of the swingable roller arm 20 . the tension roller 13 is positioned so as to extend across the winding path 21 ( for example , shown as a zigzag line in fig1 ) of the printing paper 3 and moves at a right angle to the web . the tension roller 13 can swing reciprocatingly up and down along a circular arc , as shown by arrows in fig1 , according to the winding state of the printing paper 3 . the roller reciprocates along a guide in the form of a circular arc , guide groove 22 formed in the vertical wall surface section 11 a of the housing . this swinging changes the length of the winding path 21 from minimum to maximum and , corresponding to this change , changes the bending angle ( s ) of the winding path 21 from maximum or more obtuse to minimum or more acute . fig3 is a side view of the vertical wall surface section 11 a taken from the surface on the opposite side from the surface where the tension roller 13 is positioned . the position of the tension roller 13 can be detected using a sensor plate 23 , a first sensor 24 , and a second sensor 25 . the sensor plate 23 is mounted on the roller rotary shaft 19 and rotates together with the tension roller 13 about the roller rotary shaft 19 . two detection protrusions ( first detection protrusion 26 and second detection protrusion 27 ) and three detection recesses ( first detection recess 28 , second detection recess 29 , and third detection recess 30 ) can be detected by the first sensor 24 and the second sensor 25 . the protrusions and recesses alternate on the peripheral section of the sensor plate 23 . transmission - type or reflection - type detectors can be employed for the first sensor 24 and the second sensor 25 . they are arranged on the circumference in positions enabling the detection of the first detection protrusion 26 , second detection protrusion 27 , first detection recess 28 , second detection recess 29 , and third detection recess 30 . in the lowermost position ( lower dead center , first tension region ) of the tension roller 13 shown solid line in fig3 , the first sensor 24 is close to the second detection recess 29 , and the second sensor 25 is close to the third detection recess 30 . the roller rotary shaft 19 is preferably arranged vertically above the tension roller 13 . depending on their mutual arrangement , a posture can be naturally assumed under gravity in which the tension roller 13 is positioned vertically below and inside the circular arc guide groove 22 . in this way , the tension roller 13 can constantly apply a predetermined tension on the printing paper 3 that comes into contact with the roller from above , as shown in fig1 and fig2 . furthermore , if deemed necessary , the tension roller 13 can be constantly impelled toward the lowermost section ( lower dead center ) inside the circular arc guide groove 22 by mounting a tension spring 31 ( fig1 ) on the roller arm 20 . fig4 is a table showing tension regions where the tension roller 13 is positioned . those regions are distinguished by the detection signals of the first sensor 24 and the second sensor 25 . fig5 is an explanatory drawing schematically describing each tension region . the solid line state in fig3 illustrates the lower dead center 13 , which is a lowermost point in the first tension region r 1 . in this state , the first sensor 24 detects the position of the second detection recess 29 , and the second sensor 25 detects the position of the third detection recess 30 . as the tension roller 13 rises clockwise in fig3 inside the circular arc guide groove 22 , the first sensor 24 and the second sensor 25 detect the first detection protrusion 26 , second detection protrusion 27 , first detection recess 28 , second detection recess 29 , and third detection recess 30 and generate detection signals . based on the detection signals , the winding control unit 18 determines the tension region ( first tension region r 1 , second tension region r 2 , third tension region r 3 , and fourth tension region r 4 arranged continuously and adjacently to each other ) in which the tension roller 13 is then positioned . the detection timing of the tension regions ( boundary sections of the first tension region r 1 , second tension region r 2 , third tension region r 3 , and fourth tension region r 4 ) of the tension roller 13 can be adjusted by appropriately selecting the circumferential angles of the first detection protrusion 26 , second detection protrusion 27 , first detection recess 28 , second detection recess 29 , and third detection recess 30 about the roller rotary shaft 19 of the sensor plate 23 and the relative positions of the first sensor 24 and second sensor 25 . returning to fig1 and fig2 , the winding unit 15 has a drive motor ( drive unit ) 32 , a winding shaft 33 , which is rotary driven by the drive motor 32 , a winding core or spindle 34 that is removably fit onto the winding shaft 33 , rotates integrally with the winding shaft 33 , and winds the printing paper 3 thereon in the form of a roll . a pair of paper guides 35 provided at both ends of the rewind core 34 guide the printing paper 3 . the control unit 16 is provided in the portion of the device body 11 in the vicinity of the winding unit 15 . the control unit has a start - stop button 36 for starting and stopping the rotation drive of the winding shaft 33 , a status display unit 37 comprising a led that indicates the operation status of the start - stop button 36 , and a winding direction display unit 38 that indicates the winding direction of the printing paper 3 with an arrow . when the start - stop button 36 is pushed to cause winding up the printing paper 3 , the status display unit 37 is turned on . when the winding is stopped , the status display unit 37 is turned off . the winding direction display unit 38 displays the indication of rear winding or face winding of the printing paper 3 . the printing paper 3 can be a continuous label or tag paper having no adhesive surface , or it can be a label continuous body in which a plurality of label pieces 3 b are removably attached to a band - like base paper 3 a , as shown as an example in fig2 , or it can be labels , as in fig1 described below . in the case of such a label continuous body , a winding operation , in which the label pieces 3 b are wound up on the inner side ( rear side ) of a roll on the winding shaft 33 ( rewind core 34 ), is called rear winding and a winding operation , in which the label pieces are wound up on the outer side ( face side ), is called face winding . the power source switch 17 serves to turn on / off the power source of the printing paper winding device 2 . however , even if the power source switch 17 is turned on , the drive motor 32 ( drive unit ) is not actuated and the operation of winding the printing paper 3 is not yet started . the winding control unit 18 drive controls the winding unit 15 and control unit 16 based on the detection signals of the first sensor 24 and the second sensor 25 . based on the tension region ( r 1 , r 2 , r 3 , or r 4 ) in which the tension roller 13 is then positioned , the control unit controls the printing paper winding device 2 , regardless of the control signal from the printer control unit 8 ( fig1 ) of the printer 1 , that is , independently from the printer control unit 8 . in the printing paper winding device 2 and printer 1 of such configuration , the printing paper winding device 2 is placed at the printer 1 according to the posture thereof . the printing paper 3 discharged and extending from the side of the printer 1 is wrapped around the first fixed guide roller 12 , tension roller 13 , and second fixed guide roller 14 of the printing paper winding device 2 in the state shown in fig1 or fig2 . the leading end section of the printing paper 3 is attached and fixed to the winding core 34 of the winding shaft 33 . then the power source switch 17 is turned on . when the entire printing paper 3 is in a loosened state and the tension roller 13 is in the lowermost point ( lower dead center , first tension region r 1 ), and the printing paper 3 is then set on the winding path 21 , the winding control unit 18 checks that the tension roller 13 is in the first tension region r 1 when the operation of wrapping the printing paper 3 about the winding shaft 33 ( rewind core 34 ) is started . in this state , the operator continuously pushes the start - stop button 36 , and as long as the signal thereof is outputted , the winding shaft 33 is rotationally driven by the drive unit ( drive motor 32 ) at a speed lower than the usual winding speed , and the winding of the printing paper 3 by the winding shaft 33 is temporarily stopped and the initial set state is assumed when the tension roller 13 reaches the fourth tension region r 4 ( more accurately , at the point in time the tension roller reached the boundary section of the third tension region r 3 and the fourth tension region r 4 ). the usual winding speed in the printing paper winding device 2 is set higher than the carry - out speed in the process of printing and discharging the printing paper 3 with the printer 1 . furthermore , at the time at which a transition is made from the first tension region r 1 to the second tension region r 2 and then to the third tension region r 3 , the winding speed can be raised so that the start operation and winding operation can be executed at a high speed . depending on the initial set operation of the operator , the tension roller 13 can be in a tension region other than the first tension region r 1 . but in this case , too , the winding control unit 18 determines the tension region for the tension roller 13 , in the same manner as described above , rotationally drives the winding shaft 33 at a speed lower than the usual winding speed as long as the signal from the start - stop button 36 is outputted , and temporarily stops the winding of the printing paper 3 with the winding shaft 33 to obtain the initial set state when the tension roller 13 reaches the fourth tension region r 4 . when the initial set state has been completed , with the tension roller 13 set in the fourth tension region r 4 , the printer 1 is started in this state . if the printing paper 3 is printed upon and discharged , the tension roller 13 descends from the fourth tension region r 4 via the third tension region r 3 along the arcuate guide groove 22 in the direction of the second tension region r 2 and the first tension region r 1 , while maintaining its contact under the predetermined tension with the printing paper 3 in the winding path 21 . when the tension roller 13 descends to the first tension region r 1 ( more accurately , when it reaches the boundary section between the second tension region r 2 and the first tension region r 1 ), the winding of the printing paper 3 with the winding shaft 33 is restarted , and the tension roller 13 rises along the arcuate guide groove 22 , and following this winding operation , moves through the second tension region r 2 and the third tension region r 3 , and reaches again the fourth tension region r 4 , and there stops the winding . in this stopped state , the system waits for subsequent printing and discharging of the printing paper 3 by the printer 1 and , as soon as the printing paper 3 is discharged , winding is restarted , as described above , at the time when the tension roller 13 reaches the first tension region r 1 . the winding operation can be ended by pushing the start - stop button 36 in the control unit 16 . in the usual winding operation , it can be ensured that the first tension region r 1 and the fourth tension region r 4 are margin regions by operating the control so that the tension roller 13 reciprocates within the second tension region r 2 and the third tension region r 3 . in this way , the operator can conduct the winding operation of the initial setting of the printing paper 3 at a rate slower than the usual winding rate by merely continuously pushing the start - stop button 36 in the control unit 16 . therefore , at the time of initially setting control of the printing paper 3 , the rotation of the printing paper 3 can be started at will and the winding operation can be conducted safely and reliably . the present invention is especially advantageous when a printing paper 3 with a low resistance to bending stresses is wound . in contrast with the above - described usual winding operation , the winding unit 15 or its drive motor 32 can be controlled so as to limit the tension region of the tension roller 13 to the predetermined range . the explanation will be provided below by using an rfid label continuous body as an example of printing paper with a low resistance to bending stresses . fig6 is a plan view illustrating an rfid label continuous body 40 ( printing paper ). the rfid label continuous body 40 has a band - like base paper 41 and a plurality of rfid labels 42 removably attached to the base paper 41 . the rfid label 42 ( radio frequency identification label ) has a label body 43 , an ic chip 44 incorporated into the label body 43 , and an antenna 45 . the ic chip 44 can read and write data remotely with an external data read / write device ( not shown in the figure ) via an antenna 45 , and data can be electronically written into the ic chip 44 and read therefrom . the portions of the rfid label continuous body 40 where the rfid labels 42 are located have especially low resistance to bending stresses . fig7 is a main enlarged side view of the tension roller 13 and the winding unit 15 portion . this figure illustrates a state in which the tension roller 13 is positioned in the first tension region r 1 . as shown in fig7 , when the tension roller 13 is positioned in the first tension region r 1 , the bending angles of the winding path 21 of the rfid label continuous body 40 become minimized or more acute . more specifically , the first bending angle θ 1 , second bending angle θ 2 , and third bending angle θ 3 become minimized , so that when the tension roller is positioned in the first tension region r 1 , the bending stresses become maximized . the first bending angle θ 1 is the bending angle of the winding path 21 of the rfid label continuous body 40 formed by the printer 1 , the first fixed guide roller 12 , and tension roller 13 . the second bending angle θ 2 is the bending angle of the winding path 21 of the rfid label continuous body 40 formed by the first fixed guide roller 12 , tension roller 13 , and second fixed guide roller 14 . the third bending angle θ 3 is the bending angle of the winding path 21 of the rfid label continuous body 40 formed by the tension roller 13 , second fixed guide roller 14 , and winding shaft 33 . in particular , in the location of the tension roller 13 in fig7 , the second bending angle θ 2 formed by the printing paper 3 becomes more obtuse and the effect of bending stresses on the rfid label continuous body 40 is minimized . fig8 is a main enlarged side view of the tension roller 13 and the winding unit 15 portion , which is similar to that shown in fig7 . this figure illustrates a state in which the tension roller 13 is positioned in the fourth tension region r 4 . in the state shown in fig8 , the first bending angle θ 1 , second bending angle θ 2 , and third bending angle θ 3 become maximized or more obtuse , so that when the tension roller is positioned in the fourth tension region r 4 , the bending stresses become minimized . in accordance with the present invention , the control is operated so that the first bending angle θ 1 , second bending angle θ 2 , and third bending angle θ 3 become closer to more obtuse angles , or so that the tension region where the tension roller 13 is positioned becomes closer to the fourth tension region r 4 . more specifically , a dip switch 46 ( fig1 , fig2 ) is provided in the device body 11 , and the tension region in which the tension roller 13 is to be positioned can be selected with the dip switch 46 . when the usual printing paper 3 is wound up , the winding control unit 18 controls the drive motor 32 so that the tension roller 13 reciprocates within the second tension region r 2 and the third tension region r 3 ( more accurately , between the boundary between the first tension region r 1 and the second tension region r 2 and the boundary between the third tension region r 3 and the fourth tension region r 4 ). but in the case of an rfid label continuous body 40 , the drive motor 32 is on / off controlled so that the tension roller 13 reciprocates from the second tension region r 2 to the fourth tension region r 4 ( more accurately , the uppermost portion or upper dead center of the fourth tension region r 4 ) or from the third tension region r 3 to the fourth tension region r 4 ( more accurately , the uppermost portion or upper dead center of the fourth tension region r 4 ). for example , when the tension roller 13 is reciprocated between the third tension region r 3 and the fourth tension region r 4 , the winding control unit 18 turns on the drive motor 32 and starts the winding operation of the rfid label continuous body 40 when the tension roller 13 reaches the third tension region r 3 ( more accurately , the boundary between the second tension region r 2 and the third tension region r 3 ). when the upper dead center of the fourth tension region r 4 is reached , the drive motor 32 is turned off and a state of waiting for the supply of the rfid label continuous body 40 from the printer 1 is assumed . the drive motor 32 is controlled so as to limit the tension roller 13 to a tension region that enables winding in the direction such that the bending angle of the winding path 21 , which follows the winding of the rfid label continuous body 40 , is close to a more obtuse angle . in this case , the rfid label continuous body 40 undergoes bending in the sections of the first fixed guide roller 12 , tension roller 13 , and second fixed guide roller 14 , wherein the rfid label 42 or the like can be prevented from being fractured or inadvertently disconnected by the above described control . furthermore , at a small or acute bending angle such as shown in fig7 , in particular in the section of the first fixed guide roller 12 and the second fixed guider roller 14 , the rfid label 42 may not follow the turning of the base paper 41 and may instead peel off from the base paper 41 ( see virtual line in the figure ). such a peeling off of the rfid label 42 can be also avoided by increasing the bending angle so as to make it close to an obtuse angle , as shown in fig8 . a web - winding apparatus 51 of this modified embodiment of fig9 and 10 comprises a first guide roller 54 and second guide - roller 55 for a continuous web 52 which can be guided along its winding path . a tension roll 58 provided on the end of a swingable tension arm 59 contacts the continuous web 52 from above and is spaced between first guide roller 54 and second guide - roller 55 . a winding spindle 56 receives and winds up the continuous web 52 . a guide in the form of circular arcuate slit 50 is formed vertically on the lateral surface 63 of the housing , along the swinging movement of the tension roll 58 . in this embodiment , a restricting member ( a catching member ) 61 is provided for selectively controlling swinging movement of the tension roll 58 over a movement range . a detecting member 62 detects the lowest position of the tension roll 58 to travel in a movement range . the detecting member 67 detects the position of the tension roll in the upper part of the tension roll 58 movement range . the lowest part is the most inferior point in the movable range in which the tension roll can travel . the tension roll 58 is provided on the one end of a tension arm 59 . the other end of the tension arm 59 is swingably connected by an arm axis 57 , and which is provided on inner side of the lateral surface 63 on the housing . the tension roll 58 can be received and supported in a circular arcuate guide in the form of a slit 60 formed vertically on the lateral surface 63 of the housing . the roll 58 extends across the winding path of the continuous web 52 . also , the tension roll 58 can be pulled downward in the circular arcuate slit 60 by a tensioning force . the tensioning force urges the tension roll 58 into contact with the continuous web 52 from upwardly in the circular arcuate slit 60 by means of a tension spring or by the weight of the tension roll 58 itself . fig1 shows the tension roll 58 in full line illustrating the lowest position in the movement range where the tension roll 58 contacts the restricting member 61 , as in full line , and the tension roll 58 is shown in chain line illustrating a another lowest position in the movement range of the tension roll 58 to be shifted which is caused by contact of the tension roll 58 in the restricting member 61 and is shown in a chained line . the restricting member 61 restricts the travel of the tension arm 59 and can hold the tension roll 58 in a selected position within the circular arcuate slit 60 , allowing the tension roll 58 to travel over an arcuate movement range that can be selected . therefore , the moveable tension roll 58 may be spaced between first guide roller 54 and second guide - roller 55 , and an angle in the winding path of continuous web 52 can be easily changeable with an end limit on the tension roll 58 travel . the tension roll 58 can be held in an upper position within the circular arcuate slit 10 to limit and select an angle in the winding path of the continuous web 52 . the restricting member 61 is a hard , but somewhat elastic , member with an h - form in cross section ( not shown ). it has spaced apart end sections across the width direction of the circular arcuate slit 60 that engage the sides of the wall of the housing at the slit and therefore which allow easy manual shifting and positioning of the member 61 along the length of the slit . also , a detecting member or sensor for the lowest part 62 is movably provided on the restricting member 61 to move with it . it can detect the lowest part of the path of the tension roll 58 to be traveled in the movement range of the tension roll 58 . furthermore , a detecting member 67 can detect the upper part of the movement range of the tension roll 58 . the tension roll 58 absorbs a rate differential provided between the feeding speed of the continuous web 52 and the winding speed of the winding apparatus 51 by depending on the swinging movement of the tension roll 58 . the detecting member 67 detects when the tension roll 58 is in the upper part of the circular arcuate slit 60 . at that time , the driven part for driving the take up spindle 56 , for example the winding motor , is disabled . the tensioning force can be controlled for the continuous web 52 allowing continuous web feeding from the printer . the tension roll 58 moves downward in accordance with the discharge of the continuous web 52 from the printer . when the tension roll 58 reaches the lowest part of the circular arcuate slit 60 , the micro - switch 62 can be turned on , to drive the winding motor to start the continuous web 52 winding . a continuous web 52 provided on the winding apparatus according to this invention may have various - shapes , rfid - tag or label , or roll - shaped - tag or label , an rfid - tag or label having an rfid inlay , an rfid inlay including a single ic comprising an ic chip 66 and a coil antenna part 65 with coil shaped provided in the middle layer of the rfid - tag or label . these are sensitive to bending stress . a reasonable bend angle can be set for the web of labels or tags , raising the position of lowest part of the movement path by arranging the restricting member 11 to restrict the movement of the tension roll 8 , which can provide a control for available winding thereof without a considerable acute angle . further , a continuous web 52 ( i . e ., a continuous label web ) having a soft adhesive agent to apply the label strip on the continuous base 64 may be provided . the swinging movement of the tension roll 58 makes an angle in the winding path , and allows the tension roll 58 to even optionally function as a peel bar . in that case , the continuous base 64 is dragged in the reverse direction which peels the labels of the label strip 53 off the continuous base 64 , since the stiffness of the elastic body of the label strip 53 is relatively increased in excess of the adhesion strength . however since the restricting member 61 can be optionally placed within the circular arcuate slit 60 , preferable rewinding can be made . although the present invention has been described in relation to particular embodiments thereof , many other variations and modifications and other uses will become apparent to those skilled in the art . it is preferred , therefore , that the present invention be limited not by the specific disclosure herein , but only by the appended claims .