Plotter

Abstract

To provide a plotter in which an assist roller does not hinder a pinch roller and an effect of pressing a medium against a work stage is sufficiently obtained.SOLUTION: A plotter comprises: a work stage 3 placed with a medium 2; a medium 2 driving roller and a pinch roller (a medium 2 feeding mechanism) for conveying the medium 2; a pen carriage 4 moving in left and right directions above the work stage 3; a rail 9 extending in the left and right directions on a front side of the pen carriage 4; and an assist roller 13 which has a front side roller and a rear side roller (a rotor) for pressing the medium 2 against the work stage 3 and is supported while attachable / detachable to / from the rail 9 and movement only in a longitudinal direction of the rail 9 is allowed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plotter having an assist roller that presses a medium against a work stage. [Background technology]

[0002] A conventional plotter equipped with an assist roller is described in, for example, Patent Document 1. The plotter disclosed in Patent Document 1 is equipped with a drive roller and a pinch roller to transport a sheet-like medium to be cut on a work stage. The medium to be cut is conveyed by rotating the drive roller and the pinch roller while sandwiched between them. The pinch roller is attached to a rotating shaft arranged parallel to the drive roller, and is arranged on the shaft end side of the rotating shaft so as to cooperate with the drive roller to sandwich both ends in the width direction of the medium to be cut. The rotating shaft is configured to be freely rotatable, and is formed to extend from one side to the other side of the work stage.

[0003] Two assist rollers are provided at the center of the axial direction of the rotating shaft to press the medium to be cut against the work stage. These assist rollers are made of linear spring material and have a cylindrical part that is wound into a cylindrical shape and through which the rotating shaft passes, and a spiral part that connects both ends of the cylindrical part to the rotating shaft. The spiral part is fixed to the rotating shaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6383196 Summary of the Invention [Problem to be solved by the invention]

[0005] The assist roller disclosed in Patent Document 1 may interfere with the pinch roller when a narrow medium is used, for example. Also, because the area where the assist roller can press the medium is limited, when a wide medium is used, a part of the medium may float up above the work stage.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a plotter in which an assist roller does not get in the way of a pinch roller and which is capable of sufficiently pressing a medium against a work stage. [Means for solving the problem]

[0007] In order to achieve this object, the plotter of the present invention comprises a work stage on which a medium is placed, a medium feed mechanism for transporting the medium above the work stage, a pen carriage that moves horizontally above the work stage in a direction perpendicular to the transport direction of the medium, a rail extending in the horizontal direction perpendicular to the transport direction upstream of the pen carriage in the transport direction, and an assist roller having a rotating body that presses the medium against the work stage, and supported on the rail so as to be detachable from the rail and movable only in the longitudinal direction of the rail.

[0008] In the plotter of the present invention, a mechanism for supporting the assist roller so that it is detachable from the rail and movable only in the longitudinal direction of the rail may include a groove formed in the rail and extending in the longitudinal direction of the rail, a slide portion formed in the assist roller into which the rail fits, a locking member provided on the assist roller so as to be swingable and move in and out of the groove, and a spring member for urging the locking member in the direction of entering the groove, wherein the assist roller is maintained attached to the rail when the locking member enters the groove, and the assist roller can be removed from the rail when the locking member exits the groove.

[0009] In the plotter of the present invention, the assist roller has a slide member formed in a shape that crosses the rail in the transport direction when viewed from above and is provided with the slide portion, the groove is formed at the downstream end of the rail in the transport direction, the locking member is formed in a shape that extends in the vertical direction and is configured to swing in the transport direction with its upper end protruding upward from the slide member, and a convex portion that enters and exits the groove may be provided at the lower end of the locking member.

[0010] The present invention may be configured such that, in the plotter, the assist roller has a support shaft extending in the longitudinal direction of the rail downstream of the rail in the transport direction, and the rotating body has a contact portion formed in a coil shape from a linear spring material, and a pair of shaft portions connected to the contact portion via connecting portions made of the spring material extending from both ends of the contact portion in the opposite direction to the contact portion, formed in a ring shape positioned on the same axis as the contact portion, and supported rotatably on the support shaft, and when the contact portion is displaced upward relative to the shaft portions and the connecting portions bend, the spring reaction force generated in the connecting portions presses the contact portion against the medium.

[0011] In the plotter of the present invention, the assist roller has a lever extending in the transport direction above the rail and extending in a vertical direction upstream of the rail in the transport direction, the lever being configured to be swingable so that one end extending in the vertical direction upstream of the rail in the transport direction can move in a vertical direction, and a roller for pressing the medium against the work stage may be freely rotatably provided at the lower end of the one end. Effect of the Invention

[0012] It is possible to provide a plotter in which the assist roller does not get in the way of the pinch roller and the effect of pressing the medium against the work stage can be sufficiently obtained. [Brief description of the drawings]

[0013] [Figure 1]FIG. 1 is a perspective view of a plotter according to the present invention. [Diagram 2] FIG. 2 is a side view of the pinch roller unit. [Diagram 3] FIG. 3 is a perspective cross-sectional view of the rail. [Figure 4] FIG. 4 is a perspective view of the assist roller. [Diagram 5] FIG. 5 is a perspective view of the assist roller. [Figure 6] FIG. 6 is a side view of the assist roller. [Figure 7] FIG. 7 is a plan view of the assist roller. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. [Figure 9] FIG. 9 is an exploded perspective view of the assist roller. [Figure 10] FIG. 10 is a rear view of the assist roller as seen from the rear. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. 6 in a state where the lever has been moved upward. [Figure 13] FIG. 13 is a perspective view of the slide member as viewed obliquely from above. [Figure 14] FIG. 14 is a perspective view of the slide member as viewed obliquely from below. [Figure 15] FIG. 15 is a diagram showing the rear roller. [Figure 16] FIG. 16 is a perspective cross-sectional view of the assist roller. [Figure 17] FIG. 17 is an enlarged cross-sectional view showing a part of the assist roller. [Figure 18] FIG. 18 is a cross-sectional view showing a state in which the slide member of the assist roller is bent. [Figure 19] FIG. 19 is a cross-sectional view showing a state in which the assist roller is removed from the rail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a plotter according to the present invention will be described in detail with reference to FIGS. The plotter 1 shown in Fig. 1 is a cutting plotter that cuts out figures and characters from a sheet-like medium 2 to be cut (hereinafter simply referred to as the medium 2), and is equipped with a work stage 3 on which the medium 2 is placed and transported, and a pen carriage 4 that supports a cutting pen (not shown). The medium 2 can be a sheet fed type or a rolled sheet.

[0015] (Explanation of the working stage and pen carriage) The work stage 3 is formed to extend in the transport direction of the medium 2 (the direction from the lower left to the upper right in FIG. 1) and in the left-right direction (the direction from the upper left to the lower right in FIG. 1), which is a horizontal direction perpendicular to the transport direction. In the following, the downstream side in the transport direction of the medium 2 is referred to as the rear side, and the upstream side in the transport direction of the medium 2 is referred to as the front side. 2, the medium 2 is transported by rotating the medium driving roller 5 while the medium 2 on the work stage 3 is sandwiched between the medium driving roller 5 and the pinch roller 6. In this embodiment, the medium driving roller 5 and the pinch roller 6 constitute the "medium feed mechanism" as referred to in the present invention.

[0016] The pen carriage 4 has a function of driving a cutting pen (not shown) in the up-down direction, and is configured to be movable in the left-right direction. The up-down direction here refers to a vertical direction that intersects with the work stage 3. The medium 2 is cut by attaching a cutting pen to the pen carriage 4, and while the medium 2 is sandwiched between the medium drive roller 5 and the pinch roller 6, rotating the medium drive roller 5 forward or backward, while inserting the cutting pen into the medium 2 and moving it left and right together with the pen carriage 4.

[0017] (Explanation of pinch roller) The pinch rollers 6 are provided in pinch roller units 7 and 8, which are depicted at two locations on the left and right sides in the vicinity of the work stage 3 in Fig. 1. These first and second pinch roller units 7 and 8 are supported by rails 9 located in the vicinity of the upper part of the work stage 3.

[0018] The rail 9 extends in the left-right direction from the left end to the right end of the work stage 3 near the upper part of the work stage 3, and is fixed to a frame (not shown) of the cutting plotter at both left and right ends. The pinch roller units 7 and 8 are supported on rails 9 so as to be movable left and right. The pinch roller 6 is supported at the rear end of the pinch roller units 7 and 8 so as to be movable up and down and rotatable. The pinch roller 6 is biased downward by the spring force of a spring member (not shown). Therefore, the medium 2 is pressed against the medium driving roller 5 by the pinch roller 6 biased by the spring force of the spring member. 1 has an operating lever 7a that can swing up and down, and the pinch roller 6 moves up and down as the operating lever 7a swings up and down around its front end. With the pinch roller 6 moving upward, the first pinch roller unit 7 is movable left and right along the rail 9.

[0019] (Rail description) The rail 9 is formed of a drawn material having a predetermined cross-sectional shape. As shown in FIG. 3, the rail 9 according to this embodiment is formed so that the cross-sectional shape is a substantially right-angled triangle, and is used in a position in which the inclined surface 9a faces rearward and upward, and the front surface 9b extends in the vertical direction. The inclined surface 9a of the rail 9 is formed with a first groove 9c extending in the left-right direction, and the front surface 9b is formed with a second groove 9d extending in the left-right direction. In addition, the rear end of the rail 9 is formed with a rear surface 9e and a third groove 9f extending in the left-right direction. The rear surface 9e is formed so as to be parallel to the front surface 9b.

[0020] A plate-like member 10 used to determine the left-right position of the first pinch roller unit 7 is attached to the first groove 9c. A recess 10a is formed on the top surface of this plate-like member 10. The recesses 10a are formed at a plurality of positions aligned at predetermined intervals in the left-right direction. The first pinch roller unit 7 is configured such that when a standard-sized medium 2 is used, the pinch roller 6 is positioned at an optimal position for the medium 2 by fitting a part of the first pinch roller unit 7 into the recess 10a.

[0021] 2, first and second engagement pieces 11, 12 provided on the first pinch roller unit 7 engage with the second groove 9d and the third groove 9f. The first and second engagement pieces 11, 12 engage with the second and third grooves 9d, 9f, thereby restricting the first pinch roller unit 7 from coming off upward relative to the rail 9. Although not shown in detail, the second pinch roller unit 8 also engages with the rail 9 in the same way as the first pinch roller unit 7, and is prevented from coming off.

[0022] (Explanation of the assist roller) 1, two assist rollers 13 are provided on the rail 9 so as to be located between the first pinch roller unit 7 and the second pinch roller unit 8. These assist rollers 13 are for pressing the medium 2 against the working stage 3 between the first pinch roller unit 7 and the second pinch roller unit 8. As shown in Figs. 4 to 7, the assist roller 13 is configured as a single assembly by assembling various functional parts to a slide member 14 that is supported by the rail 9 and protrudes rearward from the rail 9.

[0023] The assist roller 13 according to this embodiment includes a front roller 15 located at the front end and a rear roller 16 located at the rear end, and is supported by a slide mechanism 17 described later so as to be detachable from the rail 9 and movable only in the longitudinal direction (left-right direction) of the rail 9. The front roller 15 and the rear roller 16 constitute the "rotating body" as referred to in the present invention. The front roller 15 and the rear roller 16 will be described later.

[0024] The slide member 14 is formed in a shape that crosses the rail 9 in the front-rear direction when viewed from above. More specifically, the slide member 14 has a slide portion 21 into which the upper portion of the rail 9 fits, and a pair of left and right arm portions 22 that protrude rearward from the slide portion 21, as shown in Figs. 8 and 9. The slide portion 21 constitutes a part of a slide mechanism 17, which will be described later. The slide portion 21 has a protrusion 23 that engages with the second groove 9d of the rail 9 from the front, an inclined surface 24 that contacts the inclined surface 9a of the rail 9 from above, and a vertical wall 25 that contacts the rear surface 9e of the rail 9 from the rear, and is formed in a bent shape so as to follow the inclined surface 9a and front surface 9b of the rail 9. The slide member 14 according to this embodiment is made of an elastically deformable plastic material.

[0025] A pressing lever 26 is provided on the slide portion 21 of the slide member 14 at the front end of the assist roller 13 to press the medium 2 against the work stage 3. As shown in Fig. 6, the pressing lever 26 is formed in a shape that extends in the front-rear direction (the transport direction of the medium 2) above the rail 9 and also extends in the up-down direction in front of the rail 9 (upstream side in the transport direction). A cylindrical front roller 15 is rotatably supported at the lower end of the vertically extending front end of the pressing lever 26. A shaft 15a extending in the left-right direction protrudes from both axial ends of the front roller 15 as shown in Fig. 9. The shaft 15a is engaged with the lower end of the pressing lever 26 from below and rotatably supported.

[0026] 9, a pair of plates 27 extending in the front-rear and up-down directions are provided at a portion of pressing lever 26 located above rail 9 and positioned so as to sandwich slide member 14 from both left and right sides. A support shaft 28 protruding toward slide member 14 is provided on each of opposing side surfaces of plates 27. Support shaft 28 is rotatably fitted into a shaft hole 29 formed in slide member 14.

[0027] The pressing lever 26 is configured to swing relative to the slide member 14 so that its front end moves up and down around a support shaft 28. By swinging the pressing lever 26 so that its front end moves upward as shown by the two-dot chain line in Fig. 6, the gap between the front end (front roller 15) of the assist roller 13 and the work stage 3 widens, making it easier to insert the medium 2 into the initial position. In addition, when an automatic sheet feeder (not shown) is used, it is possible to prevent the front end of the assist roller 13 from interfering with the automatic sheet feeder.

[0028] As shown in Fig. 9, a columnar projection 30 having an arc-shaped cross section extending in the front-rear direction is provided at the rear end of plate 27 of pressing lever 26, which is a portion facing slide member 14. This columnar projection 30 is formed in an arc-shaped cross section that is convex toward slide member 14 when viewed from behind, as shown in Fig. 10. A hemispherical projection 31 is formed at a position on slide member 14 facing columnar projection 30.

[0029] When the pressing lever 26 is in the lower position shown by the solid line in Fig. 6, the top of the columnar projection 30 is located above the hemispherical projection 31 as shown in Fig. 11. When the front end of the pressing lever 26 is pulled upward from this state, the top of the columnar projection 30 passes over the hemispherical projection 31 and descends. When the pressing lever 26 is in the upper position shown by the two-dot chain line in Fig. 6, the top of the columnar projection 30 is located below the hemispherical projection 31 as shown in Fig. 12. That is, the columnar projection 30 and the hemispherical projection 31 provide the operator with a sense of moderation when the pressing lever 26 is swung, and constitute a click mechanism 32 that holds the pressing lever 26 in the lower or upper position.

[0030] The pressing lever 26 according to this embodiment is formed so that, when the pressing lever 26 is located at the lower position as shown in Fig. 11, the convex curved surface of the columnar projection 30 is pressed against the semispherical projection 31 with a predetermined pressing force. Therefore, when the pressing lever 26 is located at the lower position, the pressing lever 26 is biased in a direction in which the top of the columnar projection 30 moves away from the semispherical projection 31 (upward in Fig. 11) due to the so-called inclined cam principle. At this time, the pressing lever 26 is biased in a direction in which the front roller 15 moves toward the working stage 3. As a result, in this assist roller 13, the front roller 15 presses the medium 2 against the working stage 3 without using a spring member.

[0031] As shown in Fig. 7, the pair of left and right arm portions 22 of the slide member 14 are formed to be aligned at a predetermined interval in the left-right direction. At the rear end of the arm portion 22, on the inner surface facing the other arm portion 22, a support shaft 33 is provided protruding toward the other arm portion 22. The support shaft 33 is formed in a cylindrical shape extending in the longitudinal direction of the rail 9 behind the rail 9 (downstream side in the conveying direction). As shown in Figs. 13 and 14, an annular groove 34 is formed in the middle portion of the support shaft 33 in the axial direction. In addition, a tapered surface 35 is formed at the protruding end of the support shaft 33, the outer diameter of which gradually decreases toward the protruding end.

[0032] The rear rollers 16 are attached to these support shafts 33 . The rear roller 16 according to this embodiment is formed by winding a linear spring material 36 into a predetermined shape, as shown in Fig. 15(A) to (C). Fig. 15(A) is a plan view of the rear roller, Fig. 15(B) is a side view of the rear roller, and Fig. 15(C) is a perspective view of the rear roller. The rear roller 16 has a contact portion 16a formed into a coil shape by the linear spring material 36, and a pair of shaft portions 16c connected to the contact portion 16a via connecting portions 16b made of the spring material 36 extending from both ends of the contact portion 16a in the opposite direction to the contact portion 16a.

[0033] The connecting portion 16b is formed into a shape that becomes a part of a helical spring. The shaft portion 16c is formed into a ring shape that is located on the same axis as the contact portion 16a, and is inserted into an annular groove 34 formed in the support shaft 33 of the slide portion 21. The inner diameter of the shaft portion 16c is smaller than the outer diameter of the support shaft 33 of the slide member 14 and slightly larger than the outer diameter of the groove bottom consisting of the cylindrical surface of the annular groove 34 of the support shaft 33, and is a diameter such that the shaft portion 16c inserted into the annular groove 34 can freely rotate within the annular groove 34.

[0034] 14, a notch 37 that communicates between the inside and outside of the annular groove 34 is formed at the tip of the support shaft 33 in order to insert the shaft portion 16c into the annular groove 34. The tip of the spring material 36 that constitutes the shaft portion 16c is passed through the notch 37, and the rear roller 16 is rotated to sequentially feed the spring material 36 into the annular groove 34, whereby the entire shaft portion 16c is guided into the annular groove 34. The shaft portions 16c at both ends of the rear roller 16 are respectively accommodated in the annular groove 34 of the support shaft 33, so that the rear roller 16 is rotatably supported by the support shaft 33.

[0035] The rear roller 16 is configured such that, with the slide member 14 attached to the rail 9, the contact portion 16a is pressed against the working stage 3, the connecting portion 16b is elastically deformed, and the contact portion 16a is displaced upward relative to the shaft portion 16c. Therefore, when the medium 2 is sandwiched between the rear roller 16 and the working stage 3, the contact portion 16a presses the medium 2 against the working stage 3 by the spring force of the connecting portion 16b.

[0036] As shown in Fig. 5, a lock lever 41, which serves as a lock member according to the present invention, is disposed between the pair of arm portions 22 of the slide member 14 and forward of the rear roller 16. The lock lever 41 is part of the slide mechanism 17 that detachably and movably mounts the assist roller 13 to the rail 9, and is supported on the slide member 14 via a support shaft 42 so as to be swingable in the front-rear direction. As shown in Fig. 16, the support shaft 42 is press-fitted into a shaft hole 43 formed in the arm portion 22 and is bridged between the pair of arm portions 22.

[0037] As shown in Figs. 8 and 9, the lock lever 41 has an operating portion 41a extending upward from the support shaft 42 and a lock portion 41b extending downward from the support shaft 42. The operating portion 41a protrudes upward from the arm portion 22. The lock portion 41b extends along the vertical wall 25 of the slide member 14 and protrudes downward from the vertical wall 25. A lock piece 44 protruding forward is provided at the lower end of the lock portion 41b. This lock piece 44 corresponds to the "protruding portion" of the present invention, and is inserted from the rear into the third groove 9f of the rail 9 in a state in which the lock portion 41b extends in the up-down direction along the vertical wall 25. In addition, the lock piece 44 comes out of the third groove 9f when the lock lever 41 swings so that the lock portion 41b moves rearward away from the vertical wall 25, as shown in Fig. 17.

[0038] A torsion coil spring 45, which serves as a spring member according to the present invention, is disposed in the center of the lock lever 41 in the axial direction of the support shaft 42. This torsion coil spring 45 biases the lock portion 41b forward (in the direction in which the lock piece 44 is inserted into the third groove 9f), and one end of the spring 45 is pressed against the rear surface of the lock portion 41b with the support shaft 42 passing through, and the other end of the spring 45 is pressed against a rear wall 46 of the arm portion 22. This rear wall 46 extends in the left-right direction to connect the left and right arm portions 22 to each other.

[0039] The lock lever 41 is biased by the spring force of the torsion coil spring 45, so that in a natural state where the operating part 41a is not operated, the lock part 41b is held in a state pressed against the vertical wall 25. In the following, the position of the lock lever 41 where the lock part 41b is pressed against the vertical wall 25 is referred to as the "lock position". Furthermore, by pushing the operating portion 41a forward against the spring force of the torsion coil spring 45, the lock lever 41 swings about the support shaft 42, and the lock portion 41b moves rearward away from the vertical wall 25. When the lock lever 41 swings as described above while the assist roller 13 is attached to the rail 9, the lock piece 44 comes out of the third groove 9f. Hereinafter, the position of the lock lever 41 in which the lock piece 44 comes out of the third groove 9f is referred to as the "unlocked position."

[0040] The slide mechanism 17, which detachably and movably mounts the assist roller 13 on the rail 9, is composed of the third groove 9f of the rail 9, the slide portion 21 of the slide member 14, the lock lever 41, and the torsion coil spring 45. According to this slide mechanism 17, the lock lever 41 is positioned at the lock position as shown in Fig. 8, so that the assist roller 13 is held so as not to be detachable from the rail 9. In this state, the slide member 14 slides relative to the rail 9, so that the assist roller 13 is movable left and right along the rail 9.

[0041] To remove the assist roller 13 attached to the rail 9 from the rail 9, first, the operating portion 41a of the lock lever 41 is pushed forward, and the lock lever 41 is swung to the unlocked position as shown in FIG. 17. Then, in this state, the rear end of the slide member 14 is grasped by hand and pulled upward, bending the slide member 14 so that the rear end is displaced upward as shown in FIG. 18. At this time, the protrusion 23 provided at the front end of the slide member 14 is engaged with the second groove 9d of the rail 9, so that the portion of the front end of the slide member 14 extending in the vertical direction is unlikely to deform. Therefore, the corner portion 51 of the bent slide member 14 is elastically deformed so as to widen.

[0042] When the slide member 14 is bent as shown in FIG. 18, the slide member 14 is moved forward and the rear end of the slide member 14 is further pulled upward, whereby the engagement between the protrusion 23 and the second groove 9d is released as shown in FIG. 19, and the assist roller 13 can be removed upward and forward from the rail 9. When attaching the assist roller 13 to the rail 9, first, the protrusion 23 of the slide member 14 is engaged with the second groove 9d of the rail 9, and the rear end of the slide member 14 is pushed down while the lock lever 41 is swung to the unlocked position. By performing this operation, the slide portion 21 of the slide member 14 fits into the rail 9 from above. After that, the lock lever 41 is released and swung to the locked position by the spring force of the torsion coil spring 45, whereby the lock piece 44 is inserted into the third groove 9f, and the assist roller 13 is attached to the rail 9 so that it cannot be removed.

[0043] The assist roller 13 in this embodiment is detachable from the rail 9, so when a narrow medium 2 is used, it can be removed to avoid interference with the first and second pinch roller units 7, 8. When a wide medium 2 is used, an additional assist roller 13 can be added so that the entire width of the medium 2 is pressed against the working stage 3. Therefore, according to this embodiment, the assist roller does not get in the way of the pinch roller, and a plotter can be provided which is sufficiently effective in pressing the medium against the working stage.

[0044] The slide mechanism 17 according to this embodiment includes a third groove 9f formed in the rail 9 and extending in the longitudinal direction of the rail 9, a slide portion 21 formed in the assist roller 13 into which the rail 9 fits, a lock lever 41 (lock piece 44) provided on the assist roller 13 so as to be swingable and move in and out of the third groove 9f, and a torsion coil spring 45 that biases the lock lever 41 in a direction into the third groove 9f. When the lock lever 41 enters the third groove 9f, the assist roller 13 is held in a state attached to the rail 9, and when the lock lever 41 exits the third groove 9f, the assist roller 13 can be removed from the rail 9. Therefore, the lock lever 41 can switch between a state in which the assist roller 13 can be removed and a state in which it cannot be removed, so that the slide mechanism 17 that makes the assist roller 13 removable can be realized at low cost with a simple structure.

[0045] The assist roller 13 according to this embodiment has a slide member 14 formed in a shape that crosses the rail 9 in the front-rear direction when viewed from above, and provided with a slide portion 21. The third groove 9f of the rail 9 is formed at the rear end of the rail 9. The lock lever 41 is formed in a shape that extends in the vertical direction, and is configured to swing in the front-rear direction with its upper end protruding upward from the slide member 14. The lower end of the lock lever 41 is provided with a lock piece 44 (convex portion) that enters and exits the third groove 9f.

[0046] Therefore, the assist roller 13 can be removed from the rail 9 by pushing the upper end (operation portion 41a) of the lock lever 41 forward and lifting the assist roller 13 forward. Since the operation direction of the lock lever 41 when removing the assist roller 13 from the rail 9 and the direction in which the assist roller 13 is lifted are substantially the same, the task of removing the assist roller 13 can be easily performed.

[0047] The assist roller 13 according to this embodiment has a support shaft 33 extending in the longitudinal direction of the rail 9 behind the rail 9. The rear roller 16 has a contact portion 16a formed in a coil shape by a linear spring material 36, and a pair of shaft portions 16c connected to the contact portion 16a via connecting portions 16b made of the spring material 36 extending from both ends of the contact portion 16a in the opposite direction to the contact portion 16a, formed in a ring shape positioned on the same axis as the contact portion 16a, and rotatably supported by the support shaft 33. When the contact portion 16a is displaced upward relative to the shaft portions 16c and the connecting portion 16b is bent, the spring reaction force generated in the connecting portion 16b presses the contact portion 16a against the medium 2. Therefore, since the medium 2 can be pushed by the spring force generated in the rear roller 16, a spring member solely for pressing the rear roller 16 against the medium 2 is not required, and the number of parts can be reduced compared to when this spring member is used.

[0048] The assist roller 13 according to this embodiment has a pressing lever 26 that extends in the front-rear direction above the rail 9 and also extends in the vertical direction in front of the rail 9. The pressing lever 26 is configured so that its front end, which extends in the vertical direction in front of the rail 9, can swing so as to move in the vertical direction. A front roller 15 that presses the medium 2 against the working stage 3 is rotatably provided at the lower end of this front end. Therefore, the medium 2 can be pressed against the working stage 3 by the front roller 15 and the rear roller 16, so that the medium 2 can be prevented from floating more reliably. In the above embodiment, an example has been shown in which the present invention is applied to a cutting plotter, but the present invention can also be applied to a pen plotter that draws characters and pictures on a sheet-like medium. [Explanation of symbols]

[0049] 1...plotter, 2...medium, 3...working stage, 4...pen carriage, 5...medium drive roller (medium feed mechanism), 6...pinch roller (medium feed mechanism), 9...rail, 9f...third groove, 13...assist roller, 14...slide member, 15...front roller (rotating body), 16...rear roller (rotating body), 16a...contact portion, 16b...connecting portion, 16c...shaft portion, 17...slide mechanism, 21...slide portion, 26...pressure lever, 33...support shaft, 41...lock lever (lock member), 44...lock piece (convex portion), 45...torsion coil spring (spring member).

Claims

1. a work stage on which the medium is placed; a medium feed mechanism for transporting the medium above the work stage; a pen carriage that moves above the work stage in a horizontal direction perpendicular to the medium transport direction; a rail extending in the horizontal direction perpendicular to the transport direction and upstream of the pen carriage in the transport direction; a rotating body for pressing the medium against the work stage, and an assist roller supported detachably on the rail and movable only in the longitudinal direction of the rail.

2. 2. The plotter of claim 1, The mechanism for supporting the assist roller so as to be detachable from the rail and movable only in the longitudinal direction of the rail comprises: a groove formed in the rail and extending in a longitudinal direction of the rail; a slide portion formed on the assist roller and into which the rail is fitted; a locking member provided on the assist roller so as to be capable of swinging in and out of the groove; a spring member that biases the locking member in a direction in which the locking member enters the groove, a locking member that enters into the groove, thereby holding the assist roller in a state attached to the rail, and a locking member that exits from the groove, thereby allowing the assist roller to be removed from the rail.

3. 3. The plotter according to claim 2, the assist roller has a slide member formed in a shape crossing the rail in the conveying direction when viewed from above and provided with the slide portion, The groove is formed at a downstream end of the rail in the conveying direction, the locking member is formed in a shape extending in a vertical direction and configured to swing in the conveying direction with an upper end protruding upward from the sliding member, A plotter according to claim 1, wherein a protrusion that fits into and out of said groove is provided at a lower end of said locking member.

4. In the plotter according to any one of claims 1 to 3, the assist roller has a support shaft extending in a longitudinal direction of the rail downstream of the rail in the conveying direction, The rotating body is a contact portion formed in a coil shape by a linear spring material; a pair of shaft portions connected to the contact portion via connecting portions made of the spring material extending from both ends of the contact portion in a direction opposite to the contact portion, formed in a ring shape positioned coaxially with the contact portion, and rotatably supported by the support shaft; A plotter characterized in that, when the contact portion is displaced upward relative to the shaft portion and the connecting portion is bent, a spring reaction force generated in the connecting portion presses the contact portion against the medium.

5. 5. The plotter according to claim 4, the assist roller has a lever extending in the transport direction above the rail and extending in the vertical direction upstream of the rail in the transport direction, the lever is configured to be swingable such that one end extending in the vertical direction on the upstream side of the rail in the conveying direction can move in the vertical direction, a roller for pressing the medium against the work stage, the roller being rotatably provided at a lower end of the one end of the plotter;

Images