Printer

Abstract

To provide a printer capable of preventing a recording medium from entering a gap in a movement direction of a detection part, even when providing the detection part movable in a width direction of the recording medium on a conveyance passage.SOLUTION: A thermal printer 1 comprises: a platen roller 30 for conveying a recording medium M1; a sensor part 53 for detecting a position in a width direction of the recording medium M1; and a first spiral guide roller 51 formed with spiral mountains 51A on a circumferential direction outer side, that is parallelly arranged in an axial direction of the platen roller 30 on an upper stream side of the platen roller 30 in a conveyance direction D of the recording medium M1. The sensor part 53 stored at a valley 51B between the spiral mountains 51A of the first spiral guide roller 51 is arranged movably in the axial direction by rotating the first spiral guide roller 51.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to printers. [Background technology]

[0002] 2. Description of the Related Art In a conventional printer, a configuration has been proposed in which a paper detection device for detecting paper is provided on a transport path of the paper to be printed.

[0003] For example, Patent Document 1 describes a paper detection device that includes a guide plate in which a long hole extending linearly along the width direction of the paper is formed, and a paper detection unit that is movable along the longitudinal direction of the long hole of the guide plate. In the paper detection device described in Patent Document 1, the paper detection unit can be moved to an appropriate position in the longitudinal direction of the long hole depending on the type of paper used (e.g., the width of the paper, etc.). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-148884 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional paper detection devices, gaps are created facing the paper (recording medium) transport path in the long holes of the guide plate other than the part where the paper detection unit (detection section) is located, which can lead to a situation where part of the paper enters the gap during transport.

[0006] The present disclosure aims to provide a printer that can prevent the recording medium from entering gaps in the movement direction of the detection unit even when a detection unit that is movable in the width direction of the recording medium is provided on the transport path. [Means for solving the problem]

[0007] A printer according to one aspect of an embodiment of the present invention comprises a platen roller that transports a recording medium, a detection unit that detects the widthwise position of the recording medium, and a spiral guide that is arranged parallel to the axial direction of the platen roller upstream of the platen roller in the transport direction of the recording medium and has spiral ridges formed on the outer circumferential side, the detection unit being housed in a valley between the ridges of the spiral guide and installed so as to be movable in the axial direction by rotation of the spiral guide. Effect of the Invention

[0008] According to the present disclosure, a printer can be provided that can prevent the recording medium from entering gaps in the movement direction of the detection unit even when a detection unit that can move in the width direction of the recording medium is provided on the transport path. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an exploded perspective view of a thermal printer according to a first embodiment; [Diagram 2] FIG. 2 is an assembled perspective view of the thermal printer shown in FIG. [Diagram 3] FIG. 1 is a perspective view of a platen unit according to a first embodiment; [Figure 4] A diagram showing the structure of the platen section from the side [Diagram 5] A perspective view of a sensor unit and a holder unit [Figure 6] A front view of the platen unit when the sensor unit is in the first position [Figure 7] FIG. 4 is a front view of the platen unit when the sensor unit is moved to the second position; [Figure 8] Rear view of the platen with the sensor in the first position [Figure 9] Rear view of the platen unit with the sensor unit moved to the second position [Figure 10] FIG. 11 is a front view of a platen portion according to the second embodiment; [Figure 11] 11 is a side view of a platen portion according to the second embodiment; [Figure 12] 11 is a cross-sectional view showing the operation of a guide portion according to the second embodiment. [Figure 13] A diagram showing the transition of the contact point between the linerless label and the first spiral guide roller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicated description will be omitted.

[0011] In the following description, the thermal printers 1 and 1A are taken as an example of the printer according to the embodiment. The printer according to the embodiment may be any printer that includes at least the spiral guide roller 51, and may include printing devices other than thermal printers.

[0012] [First embodiment] A first embodiment will be described with reference to Figures 1 to 9. Figure 1 is an exploded perspective view of a thermal printer 1 according to the first embodiment. Figure 2 is an assembled perspective view of the thermal printer 1 shown in Figure 1.

[0013] 1 and 2, the thermal printer 1 includes two unit components: a platen unit 10 and a printing unit 20. A platen roller 30 is rotatably supported and attached to the platen unit 10. A thermal head 40 is attached to the printing unit 20.

[0014] As shown by the dotted arrow in Fig. 1, the platen unit 10 and the printing unit 20 can be connected as shown in Fig. 2 by engaging or butting the respective parts of the platen unit 10 and the printing unit 20 with each other. In the connected state of Fig. 2, the platen roller 30 of the platen unit 10 and the thermal head 40 of the printing unit 20 are disposed opposite each other and come into contact with each other. A recording medium M1 (see Fig. 4) such as paper is conveyed by rotating the platen roller 30 while being sandwiched between the platen roller 30 and the thermal head 40, and printing is performed by the thermal head 40. In the examples of Figs. 1 and 2, the conveying direction of the recording medium M1 is from the lower left side of the paper to the upper right side of the paper, with the lower left side of the paper being the upstream side in the conveying direction and the upper right side of the paper being the downstream side in the conveying direction.

[0015] The platen unit 10 includes a guide unit 50 upstream of the platen roller 30 in the transport direction for guiding the recording medium M1 to the platen roller 30. The printing unit 20 includes a guide member 60 upstream of the thermal head 40 in the transport direction for guiding the recording medium M1 to the thermal head 40. The guide unit 50 and the guide member 60 are disposed opposite each other when the platen unit 10 and the printing unit 20 are connected, and the recording medium M1 can be inserted between them. The recording medium M1 passes between the guide unit 50 and the guide member 60 and is transported toward between the platen roller 30 and the thermal head 40. As shown in FIG. 1, the guide member 60 has a plane extending in the transport direction and width direction of the recording medium M1, and by at least a part of this plane coming into surface contact with one surface of the recording medium M1, the recording medium M1 can be moved downstream in the transport direction while maintaining a constant position in the thickness direction. The configuration of the guide unit 50 will be described later with reference to FIG. 3 and subsequent figures.

[0016] FIG. 3 is a perspective view of the platen unit 10 according to the first embodiment. FIG. 3 is a perspective view of the platen unit 10 as viewed from the rear of the paper of FIGS. 1 and 2, and as viewed from the direction in which the platen roller 30 is exposed. FIG. 4 is a diagram showing the structure of the platen unit as viewed from the side. FIG. 4(A) is a side view, and FIG. 4(B) is a cross-sectional view. Arrow D in FIG. 4(B) indicates the transport direction of the recording medium M1. Also, in FIG. 4, the printing unit 20 is disposed opposite the side of the platen unit 10 where the platen roller 30 is exposed.

[0017] 3 and subsequent figures show three mutually perpendicular directions, the X direction, the Y direction, and the Z direction. The X direction is the transport direction D of the recording medium M1, with the negative X direction side being the upstream side of the transport direction D and the positive X direction side being the downstream side of the transport direction D. The Y direction is the axial direction of the platen roller 30 and the spiral guide rollers 51 and 52, and is the width direction of the recording medium M1 being transported. The Z direction is the opposing direction between the recording medium M1 being transported and the guide unit 50.

[0018] 3 and 4, in the platen unit 10, a guide unit 50 is provided upstream of the platen roller 30 in the transport direction of the recording medium M1. The guide unit 50 has a first spiral guide roller 51, a second spiral guide roller 52, and a sensor unit 53. The sensor unit 53 is an example of a detection unit.

[0019] The first spiral guide roller 51 and the second spiral guide roller 52 are arranged parallel to the axial direction of the platen roller 30, and spiral peaks 51A, 52A are formed on the outer circumferential sides. In addition, valleys 51B, 52B recessed in the axial direction are formed between the spiral peaks 51A, 52A. The first spiral guide roller 51 houses a sensor unit 53. The second spiral guide roller 52 is arranged adjacent to the first spiral guide roller 51 on the downstream side in the conveying direction D.

[0020] 4(B), the first spiral guide roller 51, the second spiral guide roller 52, and the platen roller 30 are disposed adjacent to each other in this order from the upstream side to the downstream side in the transport direction D. The outer edge positions of the first spiral guide roller 51, the second spiral guide roller 52, and the platen roller 30 on the positive Z direction side are aligned at the same position, so that the radial outer edge of each roller is disposed so as to be able to come into contact with the recording medium M1.

[0021] The sensor unit 53 detects the position in the width direction of the recording medium M1. As shown in Figures 3 and 4(B), the sensor unit 53 is accommodated in a valley 51B between peaks 51A of the first spiral guide roller 51 and is installed so as to be movable in the axial direction by the rotation of the first spiral guide roller 51.

[0022] Any type of sensor, such as an optical sensor (such as a photointerrupter), can be applied to the sensor unit 53. Any detection method can be applied to the sensor unit 53, such as a method of detecting the edge of the recording medium M1 in the width direction, or a method of detecting a mark printed in advance on the back surface opposite the printed surface of the recording medium M1. Furthermore, the sensor unit 53 may be replaced with an element other than a sensor as long as it can function as a detection unit that can detect the position of the recording medium M1 in the width direction.

[0023] 3, the platen unit 10 has a pair of support plates 54, 55 arranged opposite to each other in the Y direction. The platen roller 30, the first spiral guide roller 51, and the second spiral guide roller 52 are housed between the pair of support plates 54, 55, and both ends of their respective rotation shafts are journaled by the support plates 54, 55, respectively.

[0024] The first spiral guide roller 51 and the second spiral guide roller 52 are installed so as to be rotatable in conjunction with each other. For example, as shown in FIG. 3 and FIG. 4(A), a first gear 51C is installed concentrically and integrally rotatably at one end of the rotation shaft of the first spiral guide roller 51. A second gear 52C is installed concentrically and integrally rotatably at one end of the rotation shaft of the second spiral guide roller 52. Here, the first gear 51C and the second gear 52C are installed at the end of each guide roller 51, 52 supported by one support plate 54, on the main surface side (Y negative direction side) of the pair of main surfaces of the support plate 54 facing the opposite side to the guide rollers 51, 52. Furthermore, a third gear 56 is installed between the first gear 51C and the second gear 52C, which meshes with both the gears 51C, 52C. The third gear 56 is also disposed on one of the pair of main surfaces of the support plate 54 facing away from the guide rollers 51, 52 so as to be rotatable around an axis parallel to the rotation axes of the guide rollers 51, 52.

[0025] In this way, the two guide rollers 51, 52 are connected via the first gear 51C, the third gear 56, and the second gear 52C, so that both guide rollers 51, 52 can rotate in the same direction in an interlocking manner. For example, as shown in Fig. 4(A), when the first spiral guide roller 51 and the first gear 51C rotate in the direction of the arrow A, the third gear 56 rotates in the opposite direction as shown by the arrow B. The second gear 52C meshing with the third gear 56 rotates in the opposite direction to the third gear 56, i.e., in the same direction as the first gear 51C, and as a result, the second spiral guide roller 52 rotates in the same direction as the first spiral guide roller 51 in an interlocking manner as shown by the arrow C.

[0026] As shown in Figure 3, the pitch P1 of the spiral shape of the first spiral guide roller 51, i.e., the distance between adjacent peaks 51A at the same circumferential position, and the pitch P2 of the spiral shape of the second spiral guide roller 52, i.e., the distance between adjacent peaks 52A at the same circumferential position, are the same.

[0027] As shown in FIG. 4B, the first spiral guide roller 51 and the second spiral guide roller 52 are installed so that the phase difference θ is 90 degrees. As shown in FIG. 4B, in a cross section at an arbitrary position in the axial direction, a straight line L1 is considered that connects the axis O1 of the first spiral guide roller 51 and the axis O2 of the second spiral guide roller 52. "The phase difference θ is 90 degrees" means that the angle between the direction to the crest 51A of the first spiral guide roller 51 and the direction to the position of the crest 52A of the second spiral guide roller 52 with respect to the straight line L1 in this cross section is 90 degrees. In the example of FIG. 4B, the crest 51A is on the straight line L1, and the crest 52A is on the straight line L2 that is perpendicular to the straight line L1. By setting the phase difference θ between the first spiral guide roller 51 and the second spiral guide roller 52 to 90 degrees in this way, it is possible to more reliably prevent the crests 51A and 52A of the guide rollers 51 and 52 from interfering with each other.

[0028] Furthermore, by the guide rollers 51, 52 rotating in conjunction with each other while maintaining this phase difference θ as described above, it is possible to maintain a state in which the peaks 52A of the second spiral guide roller 52 block the valleys 51B of the first spiral guide roller 51. Such operation of the guide rollers 51, 52 can more reliably prevent a portion of the conveyed recording medium M1 from entering the gap between the first spiral guide roller 51 and the second spiral guide roller 52.

[0029] Fig. 5 is a perspective view of the sensor unit 53 and the holder 57. Fig. 5(A) is a perspective view seen from the radial outside (Z positive direction side) of the spiral guide roller 51, and Fig. 5(B) is a perspective view seen from the axial center side (Z negative direction side) of the spiral guide roller 51.

[0030] The sensor unit 53 is installed on a holding unit 57 that is slidably installed in the axial direction of the first spiral guide roller 51. The holding unit 57 has inclined surfaces 57A and 57B that are arranged to face the inclined surfaces of the two peaks on both axial sides of the valley 51B of the first spiral guide roller. As shown in FIG. 3, the valley 51B has a bottom surface 51D that extends along the circumferential direction around the axis, and two inclined surfaces 51E and 51F that connect the bottom surface 51D to the two peaks 51A arranged on both axial sides. The inclined surfaces 57A and 57B of the holding unit 57 are formed in a curved shape that can be in surface contact with the inclined surfaces 51E and 51F of the first spiral guide roller 51, respectively. This allows the holding unit 57 on which the sensor unit 53 is installed to be reliably installed without any misalignment or rattle with respect to the valley 51B of the first spiral guide roller 51, making it possible to more stably position and move the sensor unit 53 in the axial direction.

[0031] The holding portion 57 has an installation surface 57C that faces radially outward from the first spiral guide roller 51 when the holding portion 57 is engaged with the valley 51B of the first spiral guide roller 51. The sensor portion 53 is installed on the installation surface 57C. As a result, as shown in FIG. 4B, the sensor portion 53 is installed on the holding portion 57 such that the detection direction E always faces the recording medium M1 side, regardless of the axial movement of the holding portion 57.

[0032] Sensor unit 53 includes an optical sensor, a board for controlling the optical sensor, etc. Wiring 53A for communicating with sensor unit 53 passes through holding unit 57 from installation surface 57C, is drawn out to the rear side (negative Z direction side) where inclined surfaces 57A and 57B are arranged, and is drawn out to the rear side of platen unit 10 (the front side of the paper in FIGS. 1 and 2) through wiring insertion port 57D.

[0033] As shown in FIG. 3 and FIG. 5, the holding portion 57 has a protrusion 57E formed on the upstream side in the conveying direction D, protruding from the outer edge of the first spiral guide roller 51 to the upstream side. The protrusion 57E has a tip 57E2 on the X negative direction side formed wider along the Z direction than the base 57E1 so that the cross section is substantially T-shaped when viewed from the axial direction of the guide roller 51 as shown in FIG. 5 and the like. Meanwhile, a guide member 58 is hung between the pair of support plates 54, 55 of the platen portion 10 on the X negative direction side along the axial direction. A slit 58A is formed in the guide member 58 along the axial direction. The base 57E1 of the protrusion 57E of the holding portion 57 is slidably installed in the slit 58A, and the tip 57E2 is arranged to protrude from the guide member 58 to the upstream side in the conveying direction D. As a result, when the holding portion 57 moves axially in conjunction with the rotation of the first spiral guide roller 51, the protrusion portion 57E slides along the slit 58A of the guide member 58, thereby stabilizing the axial movement of the holding portion 57 and maintaining the detection direction E of the sensor portion 53.

[0034] Since the holding portion 57 is fitted into the valley 51B of the first spiral guide roller 51, it has a shape that extends at an incline with respect to the conveying direction D (X direction) as shown in FIG. 3 and FIG. 5 so as to be in the same direction as the extending direction of the spiral crest 51A and valley 51B of the first spiral guide roller 51. Therefore, the installation surface 57C on which the sensor unit 53 is installed is also inclined in the same manner. In this embodiment, the sensor unit 53 is also arranged so as to be inclined with respect to the conveying direction D along the extending direction of the installation surface 57C. This makes it possible to reduce the space of the dimension of the installation surface 57C in the pitch P1 direction, so that the pitch P1 of the first spiral guide roller 51 is not restricted by the size of the sensor unit 53. Note that, if the size of the sensor unit 53 is sufficiently small compared to the pitch P1 of the first spiral guide roller 51, the sensor unit 53 may be installed so that the longitudinal direction of the sensor unit 53 is aligned with the conveying direction D or the circumferential direction of the first spiral guide roller 51.

[0035] The operation of the sensor unit 53 in the thermal printer 1 according to the first embodiment will be described with reference to FIGS.

[0036] Fig. 6 is a front view of the platen unit 10 when the sensor unit 53 is in the first position. Fig. 7 is a front view of the platen unit 10 when the sensor unit 53 has moved to the second position. Figs. 6 and 7 are views of the platen unit 10 as viewed from the positive Z direction.

[0037] The "first position" in Figure 6 refers to the axial position of the sensor unit 53 in the valley 51B between the first and second peaks 51A from the end on the Y positive side of the spiral peaks 51A of the first spiral guide roller 51 when viewed from the Z positive side.

[0038] 6 in the direction of arrow F (counterclockwise when viewed from the Y positive direction), the holding portion 57 receives a pressing force from the valley 51B of the first spiral guide roller 51 via the inclined surface 57B arranged on the Y positive direction side. This pressing force causes the protrusion 57E of the holding portion 57 to slide toward the Y negative direction along the slit 58A as shown by the arrow G in FIG. 7 (see also FIG. 9), so that the holding portion 57 also moves in the same direction.

[0039] As a result, the sensor unit 53 installed on the holding part 57 also moves from the first position to a second position on the Y negative side along the axial direction of the first spiral guide roller 51. The "second position" in Fig. 7 refers to the axial position of the sensor unit 53 in a valley 51B between the second and third peaks 51A from the end on the Y positive side of the spiral peaks 51A of the first spiral guide roller 51 when viewed from the Z positive side.

[0040] By increasing the amount of rotation of the first spiral guide roller 51 from the amount of rotation in Figures 6 to 7, the axial position of the sensor unit 53 can be moved further toward the negative Y direction than the second position shown in Figure 7. Similarly, by rotating the first spiral guide roller 51 in the opposite direction to the arrow F, the axial position of the sensor unit 53 can be moved toward the positive Y direction, opposite to the examples in Figures 6 and 7.

[0041] Fig. 8 is a rear view of the platen unit 10 in a state where the sensor unit 53 is in a first position. Fig. 9 is a rear view of the platen unit 10 in a state where the sensor unit 53 has moved to a second position. Figs. 8 and 9 are views of the platen unit 10 in the states of Figs. 6 and 7, respectively, as viewed from the negative Z direction.

[0042] As a result of the rotation of the first spiral guide roller 51 in the direction of arrow F shown in Figure 8, as explained with reference to Figures 6 and 7, the protrusion 57E of the retaining portion 57 slides along the slit 58A in the negative Y direction, as shown by arrow G in Figure 9, and therefore the retaining portion 57 also moves in the same direction.

[0043] 8 and 9, the wire insertion opening 57D of the holding part 57 is installed to protrude toward the Z negative side of the first spiral guide roller 51, and the wire 53A (not shown) is pulled out from the wire insertion opening 57D to the outside of the platen part 10. As the holding part 57 moves toward the Y negative side, the wire insertion opening 57D also moves in the same direction as shown in FIG. 9. This allows the wire 53A to move in the same direction as the axial position of the sensor part 53 changes, and the relative positions of the sensor part 53 and the wire 53A can be kept constant. Therefore, even if the sensor part 53 is moved in the axial direction, the occurrence of defects such as breakage of the wire 53A can be avoided.

[0044] As described with reference to Figs. 6 to 9, it is preferable to have a configuration in which the rotation of the first spiral guide roller 51 can be restricted after the first spiral guide roller 51 is rotated and the sensor unit 53 is positioned at a desired axial position according to the recording medium M1. For example, the rotation of the first spiral guide roller 51 can be restricted by a structure in which a restricting member is fitted between the external teeth of the first gear 51C of the first spiral guide roller 51. This can reliably prevent the first spiral guide roller 51 from rotating due to frictional forces generated at the contact portion with the conveyed recording medium M1 once the axial position of the sensor unit 53 is positioned. As a result, it can reliably prevent the axial position of the sensor unit 53 from changing during the printing operation.

[0045] The steeper the inclined surfaces 51E and 51F of the valley 51B, the better in order to facilitate smoother and easier movement of the holding portion 57 and the sensor portion 53 due to the rotation of the first spiral guide roller 51. Also, the larger the pitch P1, the better.

[0046] The effects of the thermal printer 1 according to the first embodiment will be described. The thermal printer 1 of the first embodiment includes a platen roller 30 that transports the recording medium M1, a sensor unit 53 that detects the position of the recording medium M1 in the width direction, and a first spiral guide roller 51 that is disposed parallel to the axial direction of the platen roller 30 upstream of the platen roller 30 in the transport direction D of the recording medium M1 and has spiral peaks 51A formed on the outer circumferential side. The sensor unit 53 is accommodated in a valley 51B between the peaks 51A of the first spiral guide roller 51, and is installed so as to be movable in the axial direction by the rotation of the first spiral guide roller 51.

[0047] With this configuration, the position of the sensor unit 53 in the width direction of the recording medium M1 can be adjusted by rotating the first spiral guide roller 51, so that the sensor unit 53 can be used for recording media M1 of various sizes, improving versatility. In addition, the first spiral guide roller 51 has a spiral ridge 51A over the entire axial direction. Therefore, at the position where the sensor unit 53 is arranged in the conveying direction D, the spiral ridge 51A of the first spiral guide roller 51 is periodically interposed between the rotation axis of the first spiral guide roller 51 and the recording medium M1 over the entire width direction of the recording medium M1, except for the part where the sensor unit 53 is arranged in the axial direction. As a result, as described with reference to Figures 6 and 7, even if the position of the sensor unit 53 is changed along the axial direction of the first spiral guide roller 51, no gap into which a part of the recording medium M1 may enter during conveyance is generated except for the part where the sensor unit 53 is arranged in the axial direction of the first spiral guide roller 51. As a result, in the thermal printer 1 of the first embodiment, even if a sensor unit 53 that is movable in the width direction of the recording medium M1 is provided on the transport path, it is possible to prevent the recording medium M1 from entering the gap in the movement direction of the sensor unit 53. Furthermore, since there is no risk of the recording medium M1 entering, automatic paper feeding is also possible.

[0048] In the thermal printer 1 of the first embodiment, the guide unit 50 has a second spiral guide roller 52 disposed adjacent to the first spiral guide roller 51, which houses the sensor unit 53, on the downstream side in the transport direction D. This allows the spiral peaks 52A of the second spiral guide roller 52 to block the valleys 51B of the first spiral guide roller 51, thereby further preventing the recording medium M1 from entering.

[0049] In the thermal printer 1 of the first embodiment, the first spiral guide roller 51 and the second spiral guide roller 52 are installed so as to be rotatable in conjunction with each other. This makes it possible to maintain a constant phase difference θ between the first spiral guide roller 51 and the second spiral guide roller 52, so that the state in which the peaks 52A of the second spiral guide roller 52 block the valleys 51B of the first spiral guide roller 51 can be maintained more reliably.

[0050] The first spiral guide roller 51 and the second spiral guide roller 52 are installed so that the phase difference θ is 90 degrees. This makes it possible to prevent the peaks 51A and 52A of the spiral guide rollers 51 and 52 from interfering with each other.

[0051] In the examples of Figures 3, 4, 6, and 7, the guide section 50 is illustrated as having two spiral guide rollers, a first spiral guide roller 51 and a second spiral guide roller 52, but it is sufficient that the guide section 50 is configured to have at least the first spiral guide roller 51 that houses the sensor section 53.

[0052] [Second embodiment] A thermal printer 1A according to the second embodiment will be described with reference to Figs. 10 to 13. Fig. 10 is a front view of a platen unit 10A of the thermal printer 1A according to the second embodiment. Fig. 10 corresponds to Fig. 6 of the first embodiment. Fig. 11 is a side view of the platen unit 10A of the thermal printer 1A according to the second embodiment. Fig. 11 corresponds to Fig. 4(A) of the first embodiment.

[0053] The thermal printer 1A of the second embodiment is a printer that uses a linerless label M2 as a recording medium. The linerless label M2 is an adhesive label without a backing paper or a backing paper, and one side of a heat-sensitive material such as heat-sensitive paper is a printing side, and the other side is coated with an adhesive to form an adhesive side.

[0054] The overall configuration of the thermal printer 1A of the second embodiment is similar to that of the thermal printer 1 of the first embodiment shown in Figures 1 and 2, except that a platen unit 10A is used. The printed surface of the linerless label M2 conveyed through the printer faces the thermal head 40 of the printing unit 20, and the adhesive surface faces the platen roller 30 of the platen unit 10A.

[0055] In conventional printers, when a linerless label M2 is used as a recording medium, there is a need to prevent the adhesive surface of the linerless label M2 from adhering to the transport path, making it difficult to transport the label. As a countermeasure to this, a configuration has been proposed in which the guide portion 50 of the platen portion 10A is provided with a plurality of ribs extending along the transport direction D and protruding toward the recording medium, similar to the guide member 60 of the printing portion 20 shown in FIG. Such a configuration with ribs is also disclosed in, for example, JP 2015-071476 A. By providing such ribs, the contact area between the adhesive surface of the linerless label M2 and the guide portion 50 during transport can be reduced, making it difficult for the adhesive surface to adhere to the transport path, and reducing the impact on the transport of the linerless label M2.

[0056] However, the above measures leave room for further improvement in terms of making the adhesive surface of the linerless label M2 less likely to adhere to the transport path. The thermal printer 1A according to the second embodiment aims to make it even more difficult for the adhesive surface of the linerless label M2 to adhere to the transport path when a linerless label M2 is used as the recording medium.

[0057] As shown in FIG. 10, the platen portion 10A of the second embodiment differs from the platen portion 10 of the first embodiment in that the guide portion 50A does not have a sensor portion 53 or a holding portion 57, and the sensor portion 53 and the holding portion 57 are not housed in the first spiral guide roller 51 in the guide portion 50A.

[0058] 10 and 11, in the platen section 10A, the first spiral guide roller 51, the second spiral guide roller 52, and the platen roller 30 are disposed adjacent to each other in this order from the upstream side to the downstream side in the conveying direction D. Also, as shown in Fig. 11, the outer edge positions of the Z positive side of the first spiral guide roller 51, the second spiral guide roller 52, and the platen roller 30 are aligned in the same position, so that the radial outer edge of each roller is disposed so as to be able to come into contact with the adhesive surface of the linerless label M2. More specifically, the first spiral guide roller 51 and the second spiral guide roller 52 are disposed so that the apex (such as the contact point N in Fig. 13) of each of the peaks 51A and 52A that is closest to the linerless label M2 on the Z positive side comes into contact with the adhesive surface of the linerless label M2.

[0059] In the second embodiment, unlike the first embodiment, no element for restricting rotation is provided on the first spiral guide roller 51 and the second spiral guide roller 52. As a result, when the linerless label M2 is conveyed, the first spiral guide roller 51 and the second spiral guide roller 52 can be rotated by an external force in the conveying direction D applied from the contact portion with the linerless label M2.

[0060] In the guide unit 50A of the platen unit 10A of the second embodiment, similarly to the first embodiment, the first spiral guide roller 51 and the second spiral guide roller 52 are preferably installed so as to be rotatable in conjunction with each other, and it is more preferable that the first spiral guide roller 51 and the second spiral guide roller 52 are installed so as to have a phase difference of 90 degrees. This allows the spiral peaks 52A of the second spiral guide roller 52 to block the valleys 51B of the first spiral guide roller 51, further preventing the linerless label M2 from entering between the rollers.

[0061] Fig. 12 is a cross-sectional view showing the operation of a guide portion 50A according to the second embodiment, which corresponds to Fig. 4(B) of the first embodiment.

[0062] 12(A), the leading end M2t of the linerless label M2 is about to enter the gap between the first spiral guide roller 51 and the second spiral guide roller 52, but the peaks 51A of the first spiral guide roller 51 adhere to the adhesive surface of the linerless label M2, and the linerless label M2 is rotated in the direction of arrow I as the linerless label M2 moves in the conveying direction D. As a result, the second spiral guide roller 52 is also rotated in the same direction as shown by arrow J in conjunction with the first gear 51C, third gear 56, and second gear 52C.

[0063] 12(B), the linerless label M2 moves in the conveying direction D due to the rotation of the first spiral guide roller 51. As a result, the adhesive surface of the linerless label M2 also adheres to the peaks 52A of the second spiral guide roller 52, and the rotation of the second spiral guide roller 52 interlocking with the first spiral guide roller 51 moves the leading end M2t of the linerless label M2 in a direction H away from the gap between the first spiral guide roller 51 and the second spiral guide roller 52. Then, the rotation of the second spiral guide roller 52 sends the linerless label M2 further downstream in the conveying direction D, and the leading end M2t advances to the position of the platen roller 30.

[0064] Fig. 13 is a diagram showing the transition of the contact point between the linerless label M2 and the first spiral guide roller 51. In Fig. 13, three stages corresponding to the movement of the linerless label M2 in the conveying direction D are illustrated as (A), (B), and (C). Throughout Figs. 13(A) to (C), the linerless label M2 contacts the first spiral guide roller 51 at the same position K of the peak 51A along the conveying direction D. In each diagram of Fig. 13, the contact point of the linerless label M2 with the peak 51A is indicated by a circle.

[0065] In the first stage shown in FIG. 13(A), at a position K in the conveying direction D, the linerless label M2 is in contact with the first spiral guide roller 51 at six contact points N.

[0066] In the second stage shown in Fig. 13(B), the portion of the linerless label M2 at the contact point N in Fig. 13(A) (indicated by dotted circle No. 1 in the figure) moves downstream in the conveying direction D from position K as the linerless label M2 moves. Also, in the second stage, the first spiral guide roller 51 rotates as the linerless label M2 moves in the conveying direction D. As a result, the six contact points N between the linerless label M2 and the first spiral guide roller 51 in the second stage move in the axial direction (Y negative direction) in response to the rotation of the first spiral guide roller 51. As a result, from the first stage to the second stage, the contact points N move obliquely with respect to the conveying direction D as indicated by arrow Q.

[0067] In the third stage shown in Fig. 13(C), the portion of the linerless label M2 at the contact point N in Fig. 13(B) (indicated by dotted circle No. 2 in the figure) moves downstream in the conveying direction D from position K as the linerless label M2 moves. Also, in the third stage, the first spiral guide roller 51 rotates as the linerless label M2 moves in the conveying direction D. As a result, the six contact points N between the linerless label M2 and the first spiral guide roller 51 in the third stage move further in the axial direction (Y negative direction) in response to the rotation of the first spiral guide roller 51. As a result, from the second stage to the third stage, the contact points N move further obliquely with respect to the conveying direction D, as indicated by the arrow R.

[0068] The effects of the thermal printer 1A according to the second embodiment will be described. The thermal printer 1A includes a platen roller 30 that transports a linerless label M2 to be printed, and a first spiral guide roller 51 that is disposed parallel to the axial direction of the platen roller 30 upstream of the platen roller 30 in the transport direction D of the linerless label M2 and has spiral ridges 51A formed on the outer circumferential side. The first spiral guide roller 51 is installed so that the apex of the ridge 51A comes into contact with the adhesive surface of the linerless label M2.

[0069] With this configuration, the first spiral guide roller 51 rotates along with the transport of the linerless label M2, so that the contact point N between the linerless label M2 and the first spiral guide roller 51 can be moved sequentially in the axial direction, as described with reference to Fig. 13. This makes it even more difficult for the adhesive surface of the linerless label M2 to adhere to the transport path, so that the linerless label M2 can be guided without impeding the transport of the linerless label M2.

[0070] In the thermal printer 1A of the second embodiment, the guide unit 50A has a second spiral guide roller 52 disposed adjacent to the first spiral guide roller 51 on the downstream side in the transport direction D. This allows the spiral peaks 52A of the second spiral guide roller 52 to block the valleys 51B of the first spiral guide roller 51, further preventing the linerless label M2 from entering between the rollers. Also, since the second spiral guide roller 52 comes into contact with the linerless label M2 not only at the contact point N but also at the contact point with the linerless label M2, the linerless label M2 can be more reliably guided in the transport direction D.

[0071] In the example of Figures 10 to 13, the guide section 50A is illustrated as having two spiral guide rollers, a first spiral guide roller 51 and a second spiral guide roller 52, but it is sufficient that the guide section 50A has at least one spiral guide roller (e.g., the first spiral guide roller 51).

[0072] In the thermal printer 1A of the second embodiment, the guide unit 50A may have a third spiral guide roller arranged adjacent to the first spiral guide roller 51 on the upstream side in the transport direction D. In other words, three spiral guide rollers may be arranged adjacent to each other in the order of the third spiral guide roller, the first spiral guide roller 51, and the second spiral guide roller 52 from the upstream side to the downstream side in the transport direction D. This configuration makes it easier to guide the linerless label M2 to the first spiral guide roller 51. Also, since the linerless label M2 comes into contact with the first spiral guide roller 51 at the contact points with the second spiral guide roller 52 and the third spiral guide roller in addition to the contact point N, the linerless label M2 can be more reliably guided in the transport direction D.

[0073] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Any design modifications made by a person skilled in the art to these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples and their arrangements, conditions, shapes, etc. are not limited to those exemplified and can be changed as appropriate. The combination of each of the elements of each of the above-mentioned specific examples can be changed as appropriate as long as no technical contradiction occurs. [Explanation of symbols]

[0074] 1, 1A Thermal printer (printer), 10, 10A Platen part, 30 Platen roller, 50, 50A Guide part, 51 First spiral guide roller (spiral guide roller) 51A Mountain 51B Valley 51E, 51F sloped surface 52 second spiral guide roller, 53 sensor unit (detection unit), 57 Holding part 57A, 57B Slope

Claims

1. A platen roller for conveying a recording medium; A detection unit that detects a position in a width direction of the recording medium; a spiral guide roller disposed in parallel with an axial direction of the platen roller upstream of the platen roller in a conveying direction of the recording medium, the spiral guide roller having a spiral peak formed on an outer circumferential surface; Equipped with The detection unit is accommodated in a valley between the peaks of the spiral guide roller and is arranged to be movable in the axial direction by rotation of the spiral guide roller. Printer.

2. A platen roller for conveying a recording medium; a spiral guide roller disposed in parallel with an axial direction of the platen roller upstream of the platen roller in a conveying direction of the recording medium, the spiral guide roller having a spiral peak formed on an outer circumferential surface; Equipped with the spiral guide roller is disposed so that the peak of the peak comes into contact with the recording medium; Printer.

3. The spiral guide roller includes a first spiral guide roller and a second spiral guide roller disposed adjacent to the first spiral guide roller on the downstream side in the conveying direction.

3. The printer according to claim 1 or 2.

4. The first spiral guide roller and the second spiral guide roller are rotatably installed in conjunction with each other. The printer according to claim 3.

5. The first spiral guide roller and the second spiral guide roller are installed so that the phase difference between them is 90 degrees. The printer according to claim 3.

6. The detection unit is installed on a holding unit that is installed slidably in the axial direction of the spiral guide roller, The holding portion has an inclined surface disposed opposite to the inclined surfaces of the two peaks on both axial sides of the valley of the spiral guide roller, The printer of claim 1 .

7. a third spiral guide roller disposed adjacent to the first spiral guide roller on the upstream side in the conveying direction; The printer according to claim 3.

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