Elastic body roller

Abstract

To prevent electricity from flowing into another member when an elastic body roller is used for a printer while the elastic body roller is configured to have a conductive material.SOLUTION: An embodiment of the present invention is an elastic body roller for conveying a strip member. The elastic body roller comprises a roller shaft, a first non-conductive elastic material that is attached to an outer periphery of the roller shaft, and a second conductive elastic material that is attached to an outer periphery of the first elastic material.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an elastic roller. [Background technology]

[0002] 2. Description of the Related Art Various elastic rollers, such as platen rollers, have been proposed for conveying print media such as labels in thermal printers. For example, Patent Document 1 describes an elastic roller that includes an elastic material having an inner layer elastic material provided on the outer periphery of a roller shaft and a covering layer provided on the outer periphery of the inner layer elastic material and in contact with a strip-shaped member such as a label, the covering layer being made of a silicone resin with a C hardness of 20 degrees or less. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2014-097888 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a conventional platen roller is made of conductive silicone rubber, the current from the thermal head travels through the label, the conductive silicone rubber of the platen roller, and the metal core (e.g., stainless steel or other metal), and then to the printer frame, etc., generating a potential difference that can lead to galvanic corrosion. This issue is particularly prevalent in relatively large printers, such as industrial printers used in product manufacturing. In these relatively large printers, metal bearings are used to support the platen roller's metal core (e.g., stainless steel or other metal) in order to withstand axial loads and ensure durability (travel distance). Therefore, the current from the thermal head flows into the printer frame, etc., through the conductive silicone rubber of the platen roller, the platen roller's metal core, and the metal bearing.

[0005] Using non-conductive rubber as the material for the platen roller can prevent electricity from flowing into the thermal head, but the label feeding force must be sustainable so that it does not decrease over the period of use, and limiting the material to non-conductive rubber restricts the freedom of material selection.

[0006] Therefore, an object of the present invention is to configure an elastic roller to have a conductive material, and to prevent electricity from flowing into other components when the elastic roller is used in a printer. [Means for solving the problem]

[0007] One aspect of the present invention is an elastic roller for conveying a belt-shaped member, comprising: A roller shaft; a non-conductive first elastic member attached to the outer periphery of the roller shaft; a conductive second elastic member attached to the outer periphery of the first elastic member; The elastic roller is provided with: [Effects of the Invention]

[0008] According to one aspect of the present invention, an elastic roller is configured to include a conductive material, and when the elastic roller is used in a printer, it is possible to prevent electricity from flowing into other members. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram illustrating the internal mechanism of a printer including a platen roller according to an embodiment. [Figure 2] FIG. 1 is a perspective view of a linerless label wound into a roll. [Figure 3] FIG. 2 is a perspective view of a platen roller according to an embodiment. [Figure 4] FIG. 2 is a cross-sectional view of the platen roller according to the embodiment. [Figure 5] 3A and 3B are diagrams illustrating the configuration of the outer peripheral surface of a platen roller according to an embodiment. [Figure 6] 10A and 10B are diagrams illustrating a group of pattern areas provided on the outer peripheral surface of a platen roller according to an embodiment. [Figure 7] 7A and 7B are diagrams showing a plurality of forms for each of a plurality of characters provided in each pattern area of ​​FIG. 6. [Figure 8] 10A and 10B are diagrams illustrating a groove for visually checking wear of a platen roller according to an embodiment. [Figure 9] 10A to 10C are cross-sectional views of several modified examples of the platen roller according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] The embodiments described below are not limited to the drawings illustrated by the brief description of the drawings.

[0011] A first aspect of the present invention is an elastic roller for conveying a belt-shaped member, comprising: A roller shaft; a non-conductive first elastic member attached to the outer periphery of the roller shaft; a conductive second elastic member attached to the outer periphery of the first elastic member; The elastic roller is provided with:

[0012] According to a first aspect of the present invention, an elastic roller can be configured to have a conductive material, while preventing electricity from flowing into other components when the elastic roller is used in a printer.

[0013] A second aspect of the present invention is the elastic roller according to the first aspect, wherein the elastic roller clamps the belt-shaped member between itself and a thermal head and transports the belt-shaped member by rotating.

[0014] According to the second aspect of the present invention, it is possible to prevent electricity from flowing from the thermal head to other members.

[0015] A third aspect of the present invention is an elastic roller according to the first or second aspect, wherein the tear strength of the first elastic material, as defined by JIS K6252, is greater than the tear strength of the second elastic material.

[0016] According to a third aspect of the present invention, the tear strength of the first elastic material on the inner layer side is greater than that of the second elastic material on the outer layer side. Therefore, even if a second elastic material with a lower tear strength is used, the first elastic material with a relatively higher tear strength reinforces the second elastic material, thereby increasing the overall tear strength.

[0017] A fourth aspect of the present invention is an elastic roller described in any of the first to third aspects, in which the second elastic material is formed to cover at least a portion of the axial end of the roller shaft of the first elastic material and to be out of contact with the roller shaft.

[0018] According to a fourth aspect of the present invention, it is possible to prevent electricity from flowing from the roller shaft to other members via the end of the second elastic material, and it is also possible to reinforce the second elastic material.

[0019] A fifth aspect of the present invention is an elastic roller described in any of the first to fourth aspects, wherein the first elastic material is at least partially configured to have a tapered shape along the axial direction of the roller shaft.

[0020] According to the fifth aspect of the present invention, it is possible to stably transport a particularly narrow strip-shaped member.

[0021] A sixth aspect of the present invention is an elastic roller according to the fifth aspect, in which the diameter of the first elastic material in a plane perpendicular to the axial direction of the roller shaft gradually decreases from the center of the first elastic material toward both ends in the axial direction of the roller shaft.

[0022] According to the sixth aspect of the present invention, it is possible to stably transport a particularly narrow belt-shaped member.

[0023] A seventh aspect of the present invention is an elastic roller described in the fifth aspect, in which the diameter of the first elastic material in a plane perpendicular to the axial direction of the roller shaft gradually decreases from a first end of the first elastic material to a second end opposite the first end.

[0024] According to the seventh aspect of the present invention, it is possible to stably transport a particularly narrow strip-shaped member.

[0025] In an eighth aspect of the present invention, a groove for visually checking wear is provided on a surface of the second elastic material, The elastic roller according to any one of the first to seventh aspects has a groove portion for visualizing wear, which groove portion comprises a convex portion protruding from the surface of the second elastic material and a groove formed in the convex portion.

[0026] According to an eighth aspect of the present invention, the user can recognize when it is time to replace the elastic roller.

[0027] An embodiment of the elastic roller will be described below. First, with reference to FIGS. 1 and 2, a thermal printer equipped with a platen roller, which is an embodiment of an elastic roller, will be described.

[0028] Fig. 1 is a diagram showing the internal mechanism of a printer 1 including a platen roller 8 (an example of an elastic roller) of one embodiment. Fig. 2 is a perspective view showing a state in which a linerless label used in the printer 1 is wound in a roll. Referring to Figure 2, roll paper R is continuous paper CP (an example of a belt-shaped member) wound into a roll. As shown enlarged in Figure 2, the cross section of continuous paper CP has a label base material 31, an adhesive layer 32, a thermosensitive color former layer 33, and a release agent layer 34. The adhesive layer 32 is provided on the back side of the label base material 31. The thermosensitive color former layer 33 is provided on the front side (printing surface) of the label base material 31. The release agent layer 34 is a layer coated with a release agent such as silicone, and is provided on top of the thermosensitive color former layer 33. Position detection marks 35 are printed on the back side of the label base material 31 at predetermined intervals corresponding to the length of one label.

[0029] Referring to Figure 1, printer 1 includes an auxiliary roller 3, a label position detection sensor 4, a cutter unit 5, a printing unit 6, and a platen roller 8. In printer 1, continuous paper CP is pulled out from roll paper R as platen roller 8 rotates, and is directed toward the paper issuing port via auxiliary roller 3. The detailed structure of platen roller 8 will be described later, but it is rotatably held by a metal bearing (not shown), and holds continuous paper CP between itself and thermal head 7, transporting the continuous paper CP as it rotates. Figure 1 shows an example, but for example, auxiliary roller 3 may be omitted.

[0030] The printing unit 6 has a thermal head 7 having a plurality of heating elements arranged in a line, and by selectively activating the plurality of heating elements, the thermosensitive coloring agent layer 33 of the continuous paper CP is colored to print information on the continuous paper CP. The label position detection sensor 4 detects the position corresponding to the edge of one label (label edge position) based on the detection result of the position detection mark 35. The printer 1 adjusts the transport amount of the continuous paper CP based on the detection result of the label edge position so that printing can start from the specified position on the label. Although the position detection mark 35 has been described as an example here, the position detection mark 35 is not necessary. A light transmission sensor that detects labeled and unlabeled areas of the continuous paper CP may be used as the label position detection sensor 4, and the label edge position may be detected using this.

[0031] The cutter unit 5 includes a fixed blade 51 and a movable blade 52 for cutting the printed label. The printer 1 drives a motor (not shown) to move the movable blade 52 toward the fixed blade 51, thereby cutting the label PL. Referring to FIG. 2, the cutter unit 5 cuts the continuous paper CP at a predetermined pitch along the planned cutting line 9, thereby producing one printed label PL.

[0032] 2, the continuous paper CP (linerless label) is fed with the adhesive layer 32 on the back surface of the continuous paper CP in contact with the surface of the platen roller 8. For this reason, the platen roller 8 is configured to satisfy the requirements of non-adhesiveness to prevent jams and durability of the feeding force for feeding the continuous paper CP (linerless label) so that it does not decrease over the period of use.

[0033] Next, the configuration of the platen roller 8 will be described with reference to FIGS. 3 and 4 are a perspective view and a cross-sectional view, respectively, of the platen roller 8 according to one embodiment. As shown in FIG. 3, the platen roller 8 is an elastic roller for conveying a strip-shaped member, and includes a roller shaft 10, a first elastic member 11, and a second elastic member 12. When the platen roller 8 is mounted on the printer 1, both ends of the roller shaft 10 are rotatably held by metal bearings (not shown). A first elastic member 11 is attached to the outer periphery of the roller shaft 10. A second elastic member 12 is attached to the outer periphery of the first elastic member 11.

[0034] The roller shaft 10 is cylindrical and has a constant diameter at least in the portion where the first elastic member 11 is attached. The first elastic member 11 has a cylindrical shape. The second elastic member 12 also has a cylindrical shape, but is formed so as to cover at least a part of the end of the first elastic member 11, as will be described later. The thickness of the first elastic member 11 is, for example, within a range of 1.5 mm to 3.0 mm, but is not limited thereto. The thickness of the first elastic member 11 is typically about 3.0 mm. The thickness of the second elastic material 12 is, for example, within the range of 0.5 mm to 5 mm, but is not limited thereto. The thickness of the second elastic material 12 is typically about 1.0 mm. The ratio of the thickness of the first elastic material 11 to the thickness of the second elastic material 12 is preferably within the range of 1.5:1 to 4:1.

[0035] The roller shaft 10 is made of metal such as stainless steel. A thermoplastic elastic material or a thermosetting elastic material, for example, a silicone resin, is preferably used as the material of the first elastic material 11. A preferred example of the material of the first elastic material 11 is millable silicone rubber. The rubber hardness of the first elastic member 11 (rubber hardness according to durometer type A specified in JIS K6253) is within the range of 30 to 70 degrees. If the rubber hardness is less than 30 degrees, the first elastic member 11 becomes too soft, causing excessive friction when the platen roller 8 comes into contact with the label, resulting in a deterioration in the conveying function of the platen roller 8. If the rubber hardness exceeds 70 degrees, the first elastic member 11 becomes too hard, and insufficient friction is generated when the platen roller 8 comes into contact with the label. Therefore, if the rubber hardness is outside the above range, there is a risk that the label conveying force and / or conveying accuracy will decrease. The rubber hardness of the first elastic material 11 is higher than the rubber hardness of the second elastic material 12.

[0036] Thermosetting silicone resin or other silicone resins are used as the material of the second elastic member 12. For example, liquid silicone rubber, ultraviolet curing liquid silicone rubber, thermosetting liquid silicone rubber, etc. can be used. Similarly, the rubber hardness of the second elastic member 12 (rubber hardness measured by durometer type A according to JIS K6253) is within the range of 30 to 70 degrees.

[0037] In one embodiment, a non-conductive material is used for the first elastic material 11 on the inner layer side, and a conductive material is used for the second elastic material 12 on the outer layer side. In this configuration, electricity generated in the thermal head 7 of the printer 1 can be transmitted through the continuous paper CP to the second elastic material 12, which is a conductive material. However, because the first elastic material 11 is a non-conductive material, the electricity does not flow into the frame of the printer 1 or the like through the roller shaft 10 or the metal bearing connected to the roller shaft 10. Therefore, when the platen roller 8 is used in the printer 1, the current generated in the thermal head 7 can be prevented from being transmitted to the frame of the printer or the like, and no potential difference is generated between the thermal head 7 and the frame or the like, so galvanic corrosion or the like does not occur.

[0038] In the platen roller 8, it is preferable that the tear strength (tear strength defined by JIS K6252) of the first elastic material 11 is greater than the tear strength of the second elastic material 12. By making the tear strength of the first elastic material 11, which is the inner layer, greater than that of the second elastic material 12, which is the outer layer, even if the second elastic material 12 has a low tear strength, the first elastic material 11, which has a relatively high tear strength, reinforces the second elastic material 12, and the overall tear strength can be increased.

[0039] In one embodiment, the second elastic material 12 is formed so as to cover at least a part of the end of the first elastic material 11 in the direction of the axis CL of the roller shaft 10 (axial direction), and to be out of contact with the roller shaft 10. This makes it possible to prevent electricity from flowing into the roller shaft 10 via the end of the second elastic material 12, and also makes it possible to reinforce the first elastic material 11 by covering the end of the first elastic material 11.

[0040] 4, for example, when one end of the second elastic material 12 is focused on, the second elastic material 12 is made up of a main surface portion 121 that covers the outer periphery of the first elastic material 11, and an end portion 122R that partially covers the end surface 112R of the first elastic material 11. The main surface portion 121 of the second elastic material 12 is the portion that comes into contact with the continuous paper CP when the platen roller 8 is installed in the printer 1. The end 122R of the second elastic material 12 is not in contact with the shaft surface 101 of the roller shaft 10, and the end surface 112R of the first elastic material 11 is exposed over the entire circumference of the roller shaft 10. Therefore, even if a conductive material is used for the second elastic material 12, electrical conduction between the roller shaft 10 and the second elastic material 12 is prevented. The same applies to the other end of the second elastic material 12. Since both ends of the second elastic material 12 are formed so as to cover part of the end faces on both sides of the first elastic material 11, the second elastic material 12 is firmly bonded to the first elastic material 11. The second elastic member 12 does not have to cover the end of the first elastic member 11 in the axial direction of the roller shaft 10, and in that case, electrical conduction between the roller shaft 10 and the second elastic member 12 is also cut off.

[0041] The platen roller 8 is produced by insert molding (injection molding) in which the roller shaft 10 is set in a mold consisting of an upper mold and a lower mold. In one embodiment, the first elastic member 11 and the second elastic member 12 are injection molded. In addition, molding is performed with a cap set in the mold that contacts the end surface 112R of the first elastic material 11 and the shaft surface 101 so that the molten resin that becomes the second elastic material 12 does not come into contact with the shaft surface 101 of the roller shaft 10. As a result, the end 122R of the second elastic material 12 is molded in a shape that does not contact the shaft surface 101.

[0042] Next, the configuration of the outer peripheral surface of the second elastic member 12 will be described with reference to FIGS. In the platen roller 8, the shape of the outer peripheral surface of the second elastic material 12 that comes into contact with the linerless label is configured to satisfy the requirements of non-adhesiveness to prevent jamming when conveying the linerless label, and durability of the conveying force to convey the linerless label so that it is less likely to decrease over the period of use.

[0043] FIG. 5 is a diagram illustrating the configuration of the outer peripheral surface of the platen roller 8. As shown in FIG. 5 shows the main surface portion 121 that constitutes the outer peripheral surface of the platen roller 8, developed onto a plane along the axis CL of the roller shaft 10. The main surface portion 121 is provided with a wear visual inspection groove portion 13, which will be described later. The main surface portion 121 of the second elastic material 12 is not flat but has an uneven structure. Fig. 5 shows an enlarged example of the uneven structure. As shown in this enlarged view, the uneven structure is made up of convex regions Ri (shown in black in Fig. 5) which are regions of relatively convex parts, and concave regions Rs which are regions of relatively concave parts. The uneven structure is a structure in which, when the concave regions Rs are used as a reference, the convex regions Ri protrude from the concave regions Rs. The height of the convex regions Ri is not limited, but is in the range of 30 μm to 80 μm, for example, 50 μm.

[0044] 5, the raised areas Ri are configured such that, assuming that a group of 16 "SATO" character strings constitutes one unit, these units are repeatedly arranged adjacent to each other in the circumferential and axial directions of the roller shaft 10. This makes it easier for the linerless label to peel off from the platen roller 8, improving the durability of the non-adhesive properties.

[0045] Fig. 6 is a diagram showing a pattern area group provided on the surface of the platen roller 8. Referring to Fig. 6, one group consisting of 16 "SATO" character strings is a pattern area group G1 that includes 16 (one example of a predetermined number) pattern areas P1 to P16, each having a different shape pattern. In this pattern area group G1, each pattern area is provided along direction D1 as shown in Fig. 5. In one embodiment, each pattern area is configured to be aligned.

[0046] The platen roller 8 has raised areas Ri that come into contact with the linerless label, which are composed of multiple pattern areas each with a different shape pattern. This has the advantage of providing high non-adhesive properties for the linerless label. If the area of ​​the platen roller that adheres to the linerless label were uniform, the label would adhere with the same force throughout, making it difficult for the linerless label to peel off once it has adhered to the platen roller. In contrast, the platen roller 8 has pattern areas with different shape patterns, so the raised areas Ri of the platen roller 8 have areas with a large and small adhesive area per unit area for the linerless label. As a result, as the platen roller 8 rotates, the areas with a small adhesive area peel off first, and then (starting from there) the areas with a large adhesive area peel off more easily, resulting in high non-adhesive properties for the linerless label.

[0047] From the viewpoint of providing portions that are easy to peel and portions that are difficult to peel from the linerless label, it is preferable that pattern region group G1 contain a mixture of pattern regions with relatively large areas and pattern regions with relatively small areas. Furthermore, it is preferable to form a plurality of shape patterns in pattern region group G1 so that portions that are easy to peel and portions that are difficult to peel from the linerless label are provided in the transport direction and the axial direction. It should be noted that each of the 16 pattern regions P1 to P16 in the pattern region group G1 does not necessarily have to be formed from 16 different shape patterns, and may be formed from less than 16 different shape patterns.

[0048] FIG. 7 shows multiple forms for each of the characters ("S," "A," "T," "O") applied to each pattern area. The form corresponding to "S" in each pattern area is one of the four corresponding forms 1 to 4. The form corresponding to "A" in each pattern area is one of the five corresponding forms 1 to 5. The form corresponding to "T" in each pattern area is one of the three corresponding forms 1 to 3. The form corresponding to "O" in each pattern area is one of the three corresponding forms 1 to 3. As described above, from the perspective of providing areas with a large and small adhesion area to the linerless label per unit area, it is preferable to set multiple forms of different sizes and thicknesses as the multiple forms provided for each character. Note that "different shape patterns" means that the shape of at least one of the four characters ("S", "A", "T", and "O") is different.

[0049] The letters ("S," "A," "T," and "O") applied to each pattern area shown in Fig. 6 are merely an example, and a predetermined number of element shapes corresponding to a predetermined number of different types of letters, figures, or symbols (four in the example of Fig. 6) can be used. In other words, the shapes of the letters "S," "A," "T," and "O" that make up "SATO" in each pattern area of ​​Fig. 6 are examples of element shapes. In this case, each of the predetermined number of element shapes included in each pattern area has a form selected from a plurality of character forms, graphic forms, or symbol forms of the same type but different forms. When the element shapes are the shapes of the characters "S," "A," "T," and "O," examples of the plurality of character forms corresponding to each character are as shown in Figure 7. That is, in Figure 7, for example, four character forms are adopted for the same type of character, "S," and one of these four character forms is applied to at least one of the 16 pattern areas. By employing a plurality of configurations for each of a predetermined number of element shapes, it is possible to set a large number of pattern regions with mutually different configurations.

[0050] The element shapes corresponding to the letters, figures, or symbols applied to each pattern area preferably have few sharp points, and even more preferably have no sharp points. If each pattern area has no sharp points or is composed of element shapes with many rounded points, the adhesive of the linerless label will not or will not easily penetrate into the element shapes when the platen roller 8 rotates, further improving the non-adhesive properties of the linerless label.

[0051] In one embodiment, a direction D1 (FIG. 5) in which each pattern area is provided in the pattern area group G1 is inclined with respect to the direction of the axis CL of the roller shaft 10 (axial direction). In this case, since the multiple pattern areas P1 to P16 are arranged at an angle in the axial direction, if the shape pattern of each pattern area has a linear portion (for example, the character string "T"), the linear portion is inclined to prevent the convex areas from continuing linearly in the axial direction or the conveying direction, thereby preventing the linerless label from becoming difficult to peel in the axial direction or the conveying direction.

[0052] If the proportion of the raised regions Ri in the main surface portion 121 of the second elastic material 12 is too large, linerless labels will easily stick to it, reducing its non-adhesive properties. Conversely, if the proportion of the recessed regions Rs is too large, the area over which the linerless label adheres to the platen roller 8 will effectively decrease, reducing the conveying force for the linerless label. From this perspective, the proportion of the recessed regions Rs in the main surface portion 121 of the second elastic material 12 is within the range of 45 to 75%, and the proportion of the raised regions Ri is within the range of 25 to 55%. More preferably, the proportion of the recessed regions Rs in the main surface portion 121 of the second elastic material 12 is within the range of 60 to 65%, and the proportion of the raised regions Ri is within the range of 35 to 40%. By setting these ranges, a good balance can be achieved between non-adhesive properties for linerless labels and conveying force.

[0053] The surface roughness (arithmetic mean height Sa) of the raised regions Ri is preferably in the range of 0.5 μm to 5 μm. If the arithmetic mean height Sa is less than 0.5 μm, the surfaces of the raised regions Ri will be too smooth, making it easier for the adhesive of the linerless label to stick to the surfaces of the raised regions Ri (making jams more likely to occur). Conversely, if the arithmetic mean height Sa is more than 5 μm, the area of ​​the raised regions Ri that come into contact with the linerless label will decrease, reducing the conveying force of the linerless label. In addition, considering the case where the raised regions Ri are worn, it is preferable that the surface roughness (arithmetic mean height Sa) of the recessed regions Rs also be within the above range. As the raised regions Ri wear, the time that the linerless label is in contact with the recessed regions Rs and the pressure at that time increase. Similarly, if the surface of the recessed regions Rs is too smooth, the adhesive of the linerless label will easily stick to the surface of the recessed regions Rs, and if the surface of the recessed regions Rs is too rough, the conveying force of the linerless label will decrease. By previously subjecting the mold used for insert molding the platen roller 8 to a predetermined sandblasting process, the arithmetic mean height Sa of the convex regions Ri and the concave regions Rs can be set within the above range.

[0054] Next, the wear visual inspection groove portion 13 will be described with reference to FIG. The platen roller 8 wears over time and, once worn, is no longer able to maintain its original performance. Therefore, a wear visual inspection groove 13 is provided on the outer circumferential surface of the platen roller 8 (i.e., the surface of the second elastic material 12), and the printer 1 user can check the wear visual inspection groove 13 to determine whether the platen roller 8 needs to be replaced.

[0055] Figure 8 is a diagram illustrating the wear visual inspection groove portion 13 of the platen roller 8, and includes a front view of a portion of the platen roller 8. As shown in Figure 8, the wear visual inspection groove portion 13 has a convex portion 131 that protrudes from a reference surface 1210 of the second elastic material 12, and a groove 132 formed in the convex portion 131. The height of the convex portion 131 from the reference surface 1210 is the same as the height of the convex region Ri from the reference surface 1210. From the viewpoint of visibility by the user, the bottom surface of the groove 132 is preferably a glossy surface.

[0056] In the initial stage, the visual wear inspection groove portion 13 is recognized by the user as three lines (one top surface 1311, the groove 132, and the other top surface 1311). As the top surface 1311 of the convex portion 131 wears with use of the platen roller 8, the top surface 1311 of the convex portion 131 and the bottom surface of the groove 132 become flush with each other, and the user recognizes this as a single thick line. By positioning the bottom surface of the groove 132 shallower than the reference surface 1210, it becomes possible to determine the time to replace the convex region Ri before it is completely worn away.

[0057] 8, the protrusion 131 is formed in a band shape along the circumferential direction of the roller shaft 10, but is not limited to this. However, by forming the protrusion 131 in a band shape along the circumferential direction of the roller shaft 10, it is visually recognized by the user as a single thick line, making it easier to recognize when it is time to replace the roller shaft 10.

[0058] As described above, the platen roller 8 is made up of the roller shaft 10, the non-conductive first elastic material 11 attached to the outer periphery of the roller shaft 10, and the conductive second elastic material 12 attached to the outer periphery of the first elastic material 11. Therefore, when electricity is generated in the thermal head 7, it is possible to prevent the electricity from flowing into the frame of the printer 1 or the like through the roller shaft 10 or the metal bearing connected to the roller shaft 10. The effect of preventing the flow of electricity is exhibited whether the label is a linerless label or a liner-attached label.

[0059] Additionally, the surface (outer periphery) of the outer layer side (second elastic material 12) of the platen roller 8 is provided with an uneven structure having recessed regions Rs and raised regions Ri. This uneven structure is configured so that multiple pattern regions, each with a predetermined shape pattern, are arranged adjacent to each other in the circumferential and axial directions of the roller shaft 10. This makes it easier for linerless labels to peel off from the platen roller 8, improving the durability of their non-adhesive properties. Additionally, the raised regions Ri ensure a conveying force for the linerless labels.

[0060] As shown in FIG. 4, in the platen roller 8 described above, the first elastic member 11 and the second elastic member 12 are both cylindrical in shape, but this is not limitative and each elastic member can have various shapes. For example, in one embodiment, the first elastic member 11 is configured to have a tapered shape at least partially along the axial direction of the roller shaft 10. This allows particularly narrow linerless labels and liner-attached labels to be transported stably. Fig. 9 shows an example in which the first elastic material 11 is at least partially tapered along the axial direction of the first elastic material 11. Fig. 9 is a diagram showing cross sections of platen rollers 8A to 8D according to modified examples (a diagram corresponding to the cross section of the platen roller 8 shown in Fig. 4).

[0061] In each of the platen rollers 8A to 8D, the diameter of the first elastic material on the inner layer side varies along the axis of the roller shaft 10, and the thickness of the second elastic material on the outer layer side also varies accordingly, so the diameter of the outer circumferential surface of the second elastic material is constant. In other words, the diameter of the outer circumferential surface of the platen rollers 8A to 8D is all the same. In each of the platen rollers 8A to 8D, the diameter of the roller shaft 10 is constant in the portion where the first elastic material on the inner layer side is attached.

[0062] As mentioned above, because the rubber hardness of the first elastic material 11 is higher than that of the second elastic material 12, it is preferable to make the thickness of the first elastic material 11 relatively large and the thickness of the second elastic material 12 relatively small. By setting the thickness in this way, the rubber hardness of the entire platen roller 8 increases, allowing for greater pressure to be applied to the label when the continuous paper is clamped between the thermal head 7 and the platen roller 8, enabling stable printing. In addition, because the transport of the continuous paper is stable, meandering of the continuous paper is prevented and wear on the platen roller 8 is reduced. Here, when conveying relatively narrow linerless labels and liner-attached labels in particular, it is not necessary to increase the rubber hardness over the entire axial length of the roller shaft 10, but it is preferable to set the desired rubber hardness in the range where the label passes (the range where the label comes into contact with the platen roller). From this perspective, in the platen rollers 8A to 8D, the diameter of the first elastic material on the inner layer side is changed along the axis of the roller shaft 10 so that the rubber hardness is locally higher.

[0063] 9 has a first elastic member 11A attached to the outer periphery of a roller shaft 10, and a second elastic member 12A attached to the outer periphery of the first elastic member 11A. In the platen roller 8A, the first elastic member 11A is configured so that the diameter in a plane perpendicular to the axial direction of the roller shaft 10 gradually decreases from an end face 112AR (an example of a first end) to an end face 112AL (an example of a second end) opposite the end face 112AR. The peripheral surface 111A of the first elastic member 11A forms the outer peripheral surface of a cone. The platen roller 8A is effective when conveying a relatively narrow label by moving it to the right end (the side of the end face 112AR). In this case, the rubber hardness can be set high in the area where the label is conveyed.

[0064] 9 has a first elastic member 11B attached to the outer periphery of the roller shaft 10 and a second elastic member 12B attached to the outer periphery of the first elastic member 11B. In the platen roller 8B, the first elastic member 11B is configured so that the diameter in a plane perpendicular to the axial direction of the roller shaft 10 gradually decreases from an end face 112BR (an example of a first end) to an end face 112BL (an example of a second end) opposite the end face 112BR. The first elastic member 11B has a circumferential surface 111B-1 whose diameter gradually decreases toward the end face 112BL, and a circumferential surface 111B-2 whose diameter is constant, based on a position 201 in the axial direction of the roller shaft 10. The platen roller 8B is effective when conveying a relatively narrow label by moving it to the right end (the side of the end face 112BR). In this case, the rubber hardness can be set high in the area where the label is conveyed.

[0065] 9 has a first elastic member 11C attached to the outer periphery of the roller shaft 10, and a second elastic member 12C attached to the outer periphery of the first elastic member 11C. In the platen roller 8C, the first elastic member 11C is configured so that the diameter in a plane perpendicular to the axial direction of the roller shaft 10 gradually decreases from the center of the platen roller 8C toward both ends in the axial direction of the roller shaft 10. In other words, the first elastic member 11C has peripheral surfaces 111C-1 and 111C-2 whose diameters gradually decrease from position 202 in the axial direction of the roller shaft 10 toward both ends. The platen roller 8C is effective when a relatively narrow label is conveyed in the center (the range including the position 202). In this case, the rubber hardness can be set high in the area where the label is conveyed.

[0066] 9 has a first elastic member 11D attached to the outer periphery of the roller shaft 10 and a second elastic member 12D attached to the outer periphery of the first elastic member 11D. In the platen roller 8D, the first elastic member 11D is configured so that the diameter in a plane perpendicular to the axial direction of the roller shaft 10 gradually decreases from the center of the first elastic member 11D toward both ends in the axial direction of the roller shaft 10. That is, the first elastic member 11D has circumferential surfaces 111D-1 and 111D-3 whose diameters gradually decrease from positions 203 and 204 in the axial direction of the roller shaft 10 toward both ends, respectively. A circumferential surface 111D-2 with a constant diameter is formed between positions 203 and 204. The platen roller 8D is effective when a relatively narrow label is conveyed in the center (range of positions 202 to 204). In this case, the rubber hardness can be set high in the area where the label is conveyed.

[0067] Whichever of the platen rollers 8A to 8D is used, stable printing is possible in the range where linerless labels or liner-attached labels are transported, and transport of the continuous paper is stabilized.

[0068] 9, each of the platen rollers 8A to 8D is configured so that the roller shaft 10 and the second elastic members 12A to 12D do not come into contact with each other at both ends. That is, the end faces 112AR to 112DR and end faces 112AL to 112DL of the first elastic members 11A to 11D are exposed around the entire circumference of the roller shaft 10. Therefore, as with the platen roller 8, even if a conductive material is used for the second elastic members 12A to 12D, electricity is prevented from flowing from the second elastic members 12A to 12D to the roller shaft 10.

[0069] Although the embodiments of the elastic roller of the present invention have been described above, the present invention is not limited to these embodiments. Furthermore, various improvements and modifications to the above embodiments are possible without departing from the spirit and scope of the present invention. For example, the individual technical features described in each of the above embodiments can be combined with part or all of other embodiments as appropriate, provided that no technical contradiction occurs. [Explanation of symbols]

[0070] 1. Printer 3...Auxiliary roller 4...Label position detection sensor 5...Cutter unit 51…Fixed blade 52…Movable blade 6...Printing unit 7...Thermal head 8, 8A to 8D...Platen roller 9...Planned cutting line 10...Roller shaft 101...Shaft surface 11, 11A, 11B, 11C, 11D...First elastic material 12, 12A, 12B, 12C, 12D...Second elastic material 13... Groove for visual wear inspection 131...Protrusion, 1311...Top surface, 132...Groove 31...Label base material 32...Adhesive layer 33...Thermal color former layer 34...Release agent layer 35...Position detection mark 111A…Surrounding surface 111B-1,111B-2…Surrounding surface 111C-1,111C-2…Surrounding surface 111D-1,111D-2,111D-3…Surrounding surface 112R, 112AR, 112BR, 112CR, 112DR…End face 112AL, 112BL, 112CL, 112DL…End face 121…Main surface part 1210…Reference plane 122R…end Ri…convex area Rs…Concave area D1…direction G1: Pattern area group P1~P16...Pattern area CL…axis CP...Continuous paper PL…Label PM…Paper R...Roll paper

Claims

1. An elastic roller for conveying a belt-shaped member, A roller shaft; a non-conductive first elastic member attached to the outer periphery of the roller shaft; a conductive second elastic member attached to the outer periphery of the first elastic member; An elastic roller comprising:

2. the elastic roller holds the belt-shaped member between itself and the thermal head, and conveys the belt-shaped member by rotation; 2. The elastic roller according to claim 1.

3. The tear strength of the first elastic material as defined by JIS K6252 is greater than the tear strength of the second elastic material.

2. The elastic roller according to claim 1.

4. the second elastic member is formed to cover at least a part of an end portion of the first elastic member in the axial direction of the roller shaft, and to be out of contact with the roller shaft; 2. The elastic roller according to claim 1.

5. the first elastic member is at least partially tapered along the axial direction of the roller shaft; 2. The elastic roller according to claim 1.

6. a diameter of the first elastic member in a plane perpendicular to the axial direction of the roller shaft gradually decreases from a central portion of the first elastic member toward both end portions in the axial direction of the roller shaft; 6. The elastic roller according to claim 5.

7. a diameter of the first elastic member in a plane perpendicular to the axial direction of the roller shaft gradually decreases from a first end of the first elastic member to a second end opposite to the first end; 6. The elastic roller according to claim 5.

8. a groove for visually checking wear is provided on the surface of the second elastic material; The wear visualizing groove portion has a convex portion protruding from the surface of the second elastic material and a groove formed in the convex portion. The elastic roller according to any one of claims 1 to 7.

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