Elastic roller

Abstract

An embodiment of the present invention is an elastic roller for transferring a belt-like member having an adhesive surface in a state in which the adhesive surface of the belt-like member is in contact, the elastic roller comprising: a roller shaft; a first elastic material attached to the outer periphery of the roller shaft; and a second elastic material attached to the outer periphery of the first elastic material. An uneven structure having protruding regions and recessed regions is provided on a surface of the second elastic material. The uneven structure is configured such that a plurality of patterned regions each having a predetermined shape pattern are arranged so as to be adjacent to each other in the circumferential direction and the axial direction of the roller shaft.

Description

Elastic Roller

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

[0002] Label printers that use linerless labels are well known. Unlike liner-backed labels, in which the adhesive layer on the back of the label is temporarily and removably attached to a liner, linerless labels do not use a liner, which contributes to resource conservation. When linerless labels are fed through a printer, the label's adhesive layer is in contact with the surface of the platen roller. This requires that the label be non-adhesive to prevent jams and have a sustainable feeding force that does not decrease over the course of use.

[0003] From this perspective, various elastic rollers such as platen rollers that transport print media such as labels in response to linerless labels have been proposed.

[0004] For example, Japanese Patent Application Laid-Open No. 2014-097888 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.

[0005] Conventional elastic rollers for linerless labels lose their non-stick properties over time, posing a challenge in terms of maintaining the non-stick properties.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve the durability of non-adhesiveness in an elastic roller compatible with linerless labels.

[0007] One aspect of the present invention is an elastic roller for transporting a strip-shaped member having an adhesive surface while contacting the adhesive surface of the strip-shaped member, the elastic roller comprising: a roller shaft; a first elastic material attached to the outer periphery of the roller shaft; and a second elastic material attached to the outer periphery of the first elastic material, wherein the surface of the second elastic material is provided with an uneven structure having concave and convex regions, and the uneven structure is configured so that a plurality of pattern regions, each having a predetermined shape pattern, are arranged adjacent to each other in the circumferential and axial directions of the roller shaft.

[0008] According to one aspect of the present invention, the durability of non-adhesiveness is improved in an elastic roller compatible with linerless labels.

[0009] FIG. 7 is a diagram illustrating the internal mechanism of a printer including a platen roller of an embodiment; FIG. 8 is a perspective view of a linerless label wound in a roll; FIG. 9 is a perspective view of a platen roller of an embodiment; FIG. 10 is a cross-sectional view of a platen roller of an embodiment; FIG. 11 is a diagram illustrating the surface configuration of a platen roller of an embodiment; FIG. 12 is a diagram illustrating a group of pattern areas provided on the surface of a platen roller of an embodiment; FIG. 13 is a diagram illustrating multiple configurations for each of multiple characters provided in each pattern area of ​​FIG. 6; FIG. 14 is a diagram illustrating a groove portion for visualizing wear of a platen roller of an embodiment; FIG. 15 is a cross-sectional view of multiple modified examples of a platen roller of an embodiment;

[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 transporting a strip-shaped member having an adhesive surface while contacting the adhesive surface of the strip-shaped member, the elastic roller comprising: a roller shaft; a first elastic material attached to the outer periphery of the roller shaft; and a second elastic material attached to the outer periphery of the first elastic material, wherein the surface of the second elastic material is provided with an uneven structure having concave and convex regions, and the uneven structure is configured so that a plurality of pattern regions, each having a predetermined shape pattern, are arranged adjacent to each other in the circumferential and axial directions of the roller shaft.

[0012] According to a first aspect of the present invention, the durability of the non-adhesive property of a strip-shaped member having an adhesive surface is improved.

[0013] A second aspect of the present invention is an elastic roller according to the first aspect, in which the uneven structure is configured such that a group consisting of a predetermined number of pattern areas, each having a different shape pattern, is repeated in the circumferential and axial directions of the roller shaft, and in the group, the predetermined number of pattern areas are arranged along one direction.

[0014] According to the second aspect of the present invention, the durability of the non-adhesive property of the adhesive tape on a strip-shaped member having an adhesive surface is improved.

[0015] A third aspect of the present invention is an elastic roller according to the first or second aspect, in which the proportion of the surface of the second elastic material occupied by the concave regions is within the range of 45 to 75%, and the proportion of the surface of the second elastic material occupied by the convex regions is within the range of 25 to 55%.

[0016] According to the third aspect of the present invention, it is possible to achieve a good balance between non-adhesion and conveyance force with respect to a belt-shaped member having an adhesive surface.

[0017] A fourth aspect of the present invention is the elastic roller according to the first or second aspect, wherein the one direction is a direction inclined with respect to the axial direction of the roller shaft.

[0018] According to a fourth aspect of a certain aspect of the present invention, since the multiple pattern areas are arranged at an incline in the axial direction, when a linear portion is present in the shape pattern of each pattern area, the linear portion can be inclined, thereby preventing the strip-shaped member having an adhesive surface from becoming difficult to peel off along the axial direction or the conveying direction.

[0019] A fifth aspect of the present invention is an elastic roller described in any of the first to fourth aspects, wherein each of the predetermined number of pattern areas has a predetermined number of element shapes corresponding to a predetermined number of different types of characters, figures, or symbols, and each of the predetermined number of element shapes has a form selected from a plurality of character forms, figure forms, or symbol forms of the same type but different forms.

[0020] According to a fifth aspect of the present invention, 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 having mutually different configurations.

[0021] A sixth aspect of the present invention is the elastic roller according to any one of the first to fifth aspects, wherein the element shapes in the convex regions are configured so as not to have any sharp points.

[0022] According to the sixth aspect of the present invention, the adhesive of the belt-shaped member does not bite into the shape of the elements, resulting in good non-adhesiveness.

[0023] A seventh aspect of the present invention is an elastic roller according to any one of the first to sixth aspects, wherein the arithmetic mean height Sa of the concave regions and the convex regions is within the range of 0.5 μm to 5 μm.

[0024] According to the seventh aspect of the present invention, it is possible to improve the non-adhesiveness and conveying force with respect to a belt-shaped member having an adhesive surface.

[0025] An eighth aspect of the present invention is an elastic roller according to any one of the first to sixth aspects, wherein the first elastic material is non-conductive and the second elastic material is conductive.

[0026] According to an eighth aspect of the present invention, a conductive roller can be configured to have a conductive material, while preventing electricity from flowing into other components when the conductive roller is used in a printer.

[0027] A ninth aspect of the present invention is an elastic roller described in any of the first to sixth aspects, in which the second elastic material is formed so as to cover at least a portion of the axial end of the roller shaft of the first elastic material.

[0028] According to a ninth aspect of the present invention, the strength of the elastic roller can be increased.

[0029] A tenth aspect of the present invention is the elastic roller according to any one of the first to sixth aspects, wherein the second elastic member is not in contact with the roller shaft.

[0030] According to the tenth aspect of the present invention, it is possible to prevent electricity from flowing from the roller shaft to other members via the second elastic member.

[0031] An eleventh aspect of the present invention is an elastic roller according to any one of the first to sixth aspects, 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.

[0032] According to an eleventh 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 low tear strength is used, the first elastic material with a relatively high tear strength reinforces the second elastic material, thereby increasing the overall tear strength.

[0033] A twelfth aspect of the present invention is an elastic roller described in any of the first to sixth aspects, in which the first elastic material is configured to have a tapered shape at least partially along the axial direction of the roller shaft.

[0034] According to the twelfth aspect of the present invention, it is possible to stably transport a narrow belt-shaped member in particular.

[0035] A thirteenth aspect of the present invention is an elastic roller according to any one of the first to sixth aspects, wherein a groove for visually checking wear is provided on the surface of the second elastic material, and the groove for visually checking wear has a convex portion protruding from the surface of the second elastic material and a groove formed in the convex portion.

[0036] According to a thirteenth aspect of the present invention, the user can recognize when it is time to replace the elastic roller.

[0037] A fourteenth aspect of the present invention is an elastic roller according to any one of the first to sixth aspects, wherein the convex portion is formed in a band shape along the circumferential direction of the roller shaft.

[0038] According to a fourteenth aspect of the present invention, when the elastic roller is worn, the wear visual inspection groove becomes a single line, making it easy for the user to check the wear visual inspection groove.

[0039] An embodiment of the elastic roller will be described below: First, a thermal printer equipped with a platen roller, which is an embodiment of the elastic roller, will be described with reference to Figures 1 and 2.

[0040] FIG. 1 is a diagram showing the internal mechanism of a printer 1, including a platen roller 8 (an example of an elastic roller) according to an embodiment. FIG. 2 is a perspective view of a roll of linerless labels used in the printer 1. Referring to FIG. 2, the roll paper R is a roll of continuous paper CP (an example of a belt-shaped member). As shown enlarged in FIG. 2, the cross section of the continuous paper CP includes a label substrate 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 substrate 31. The thermosensitive color former layer 33 is provided on the front (printing surface) side of the label substrate 31. The release agent layer 34 is a layer coated with a release agent such as silicone and is provided above the thermosensitive color former layer 33. Position detection marks 35 are printed on the back side of the label substrate 31 at predetermined intervals corresponding to the length of one label.

[0041] 1, the 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 the printer 1, the continuous paper CP is pulled out from the roll paper R as the platen roller 8 rotates, and is directed toward the paper issuing port via the auxiliary roller 3. The detailed structure of the platen roller 8 will be described later, but it is rotatably held by a metal bearing (not shown), and it sandwiches the continuous paper CP between itself and the thermal head 7, transporting the continuous paper CP as it rotates. Although FIG. 1 shows an example, for example, the auxiliary roller 3 may be omitted.

[0042] The printing unit 6 has a thermal head 7 with a plurality of heating elements arranged in a line. By selectively activating the heating elements, the thermal color former layer 33 of the continuous paper CP develops color, printing information on the continuous paper CP. The label position detection sensor 4 detects the position corresponding to the label edge of one sheet (label edge position) based on the detection result of the position detection mark 35. The printer 1 adjusts the feed amount of the continuous paper CP based on the detection result of the label edge position so that printing can begin 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. The label position detection sensor 4 may be a light transmission sensor that detects labeled and unlabeled areas of the continuous paper CP, thereby detecting the label edge position.

[0043] 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 Figure 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.

[0044] 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 be non-adhesive to prevent jams and to have a sustained feed force that does not decrease over the course of use and feeds the continuous paper CP (linerless label).

[0045] Next, the configuration of the platen roller 8 will be described with reference to FIGS. 3 and 4. 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 transporting 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). The first elastic member 11 is attached to the outer periphery of the roller shaft 10. The second elastic member 12 is attached to the outer periphery of the first elastic member 11.

[0046] The roller shaft 10 is cylindrical and has a constant diameter at least at the portion where the first elastic material 11 is attached. The first elastic material 11 is cylindrical. The second elastic material 12 is also cylindrical, but as described below, is formed to cover at least a portion of the end of the first elastic material 11. The thickness of the first elastic material 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 material 11 is typically approximately 3.0 mm. The thickness of the second elastic material 12 is, for example, within a range of 0.5 mm to 5 mm, but is not limited thereto. The thickness of the second elastic material 12 is typically approximately 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 a range of 1.5:1 to 4:1.

[0047] The roller shaft 10 is made of a metal such as stainless steel. The first elastic member 11 is made of a thermoplastic elastic material or a thermosetting elastic material, preferably a silicone resin. A preferred example of the material for the first elastic member 11 is millable silicone rubber (also known as HCR (High Consistency Rubber)). The rubber hardness of the first elastic member 11 (rubber hardness measured by durometer type A according to 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, resulting in excessive friction when the platen roller 8 contacts the label, thereby reducing the conveying function of the platen roller 8. On the other hand, if the rubber hardness exceeds 70 degrees, the first elastic member 11 becomes too hard, resulting in insufficient friction when the platen roller 8 contacts the label. Therefore, if the rubber hardness is outside the above range, the label conveying force and / or conveying accuracy may be reduced. The rubber hardness of the first elastic material 11 is higher than the rubber hardness of the second elastic material 12 .

[0048] Thermosetting silicone resin or other silicone resins are used as the material for the second elastic material 12. For example, liquid silicone rubber, ultraviolet-curing liquid silicone rubber, thermosetting liquid silicone rubber, etc. can be used. The rubber hardness of the second elastic material 12 (rubber hardness measured by durometer type A specified in JIS K6253) is also within the range of 30 to 70 degrees.

[0049] 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. With 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 is 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.

[0050] 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 lower tear strength, the first elastic material 11, which has a relatively higher tear strength, reinforces the second elastic material 12, thereby making it possible to increase the overall tear strength.

[0051] In one embodiment, the second elastic material 12 is formed so as to cover at least a portion 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.

[0052] Specifically, referring to the enlarged view of FIG. 4 , for example, when focusing on one end of the second elastic material 12, the second elastic material 12 is composed 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 portion 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 around 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 is true for the other end of the second elastic material 12. Since both ends of the second elastic material 12 are formed to cover a portion 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. Note that the second elastic material 12 does not have to cover the end of the first elastic material 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 material 12 is also cut off.

[0053] The platen roller 8 is manufactured by insert molding (injection molding) with the roller shaft 10 set in a mold consisting of an upper mold and a lower mold. In one embodiment, the first elastic material 11 and the second elastic material 12 are injection molded. Note that 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.

[0054] Next, the configuration of the outer peripheral surface of the second elastic material 12 will be described with reference to Figures 5 to 7. In the platen roller 8, the configuration 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 jams when the linerless label is transported, and sustainability of the transport force to transport the linerless label so that it is less likely to decrease over the period of use.

[0055] FIG. 5 is a diagram illustrating the configuration of the outer peripheral surface of the platen roller 8. FIG. 5 shows the main surface portion 121 that constitutes the outer peripheral surface of the platen roller 8, expanded onto a plane along the axis CL of the roller shaft 10. The main surface portion 121 includes wear visual inspection grooves 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 composed of convex regions Ri (shown in black in FIG. 5 ), which are relatively convex regions, and concave regions Rs, which are relatively concave regions. In the uneven structure, the convex regions Ri are raised from the concave regions Rs, relative to 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.

[0056] 5, the raised regions 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.

[0057] 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 pattern areas P1 to P16 (an example of a predetermined number) 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.

[0058] The platen roller 8 has raised regions Ri that come into contact with the linerless label, which are composed of multiple pattern regions each having a different shape pattern, offering the advantage of high non-adhesiveness to 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 overall, making it difficult for the linerless label to peel off once it had adhered to the platen roller. In contrast, the platen roller 8 has pattern regions with different shape patterns, so the raised regions Ri of the platen roller 8 have areas with a large and small adhesive area per unit area to 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-adhesiveness to the linerless label.

[0059] From the viewpoint of providing portions that are easy to peel from the linerless label and portions that are difficult to peel, it is preferable that the 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 that the pattern region group G1 contain a plurality of shape patterns so that portions that are easy to peel from the linerless label and portions that are difficult to peel from the linerless label in the transport direction and the axial direction are provided. Note 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.

[0060] FIG. 7 shows multiple shapes for each of the characters ("S," "A," "T," and "O") applied to each pattern area. The shape corresponding to "S" in each pattern area is one of the four corresponding shapes 1 to 4. The shape corresponding to "A" in each pattern area is one of the five corresponding shapes 1 to 5. The shape corresponding to "T" in each pattern area is one of the three corresponding shapes 1 to 3. The shape corresponding to "O" in each pattern area is one of the three corresponding shapes 1 to 3. As described above, from the perspective of providing areas with large and small adhesion areas to the linerless label per unit area, it is preferable to set multiple shapes with different sizes and thicknesses as the multiple shapes 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.

[0061] The characters ("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 characters, figures, or symbols (four in the example of FIG. 6) can be used. That is, the shapes of the characters "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 is a form selected from multiple character forms, figure 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 multiple character forms corresponding to each character are as shown in FIG. 7. That is, in FIG. 7, four character forms are adopted for the same type of character, "S," for example, and one of these four character forms is applied to at least one of the 16 pattern areas. By adopting multiple forms for each of the predetermined number of element shapes, it is possible to set a large number of pattern areas with different forms.

[0062] The element shapes corresponding to the letters, figures, or symbols applied to each pattern area preferably have few sharp points, and 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-adhesiveness of the linerless label.

[0063] In one embodiment, the direction D1 (FIG. 5) in which each pattern region in the pattern region group G1 is arranged is inclined with respect to the direction (axial direction) of the axis CL of the roller shaft 10. In this case, since the multiple pattern regions P1 to P16 are arranged at an angle to the axial direction, if the shape pattern of each pattern region includes a linear portion (for example, the character string "T"), the linear portion is inclined, preventing the convex regions from being connected linearly in the axial direction or the conveying direction. This prevents the linerless label from becoming difficult to peel in the axial direction or the conveying direction.

[0064] If the proportion of the convex regions Ri in the main surface portion 121 of the second elastic material 12 is too large, the linerless label will adhere more easily, resulting in reduced non-adhesiveness. Conversely, if the proportion of the concave 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 concave 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 convex regions Ri is within the range of 25 to 55%. More preferably, the proportion of the concave 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 convex regions Ri is within the range of 35 to 40%. By setting these ranges, a good balance between non-adhesiveness for linerless labels and conveying force can be achieved.

[0065] The surface roughness (arithmetic mean height Sa) of the raised regions Ri is preferably within the range of 0.5 μm to 5 μm. If the arithmetic mean height Sa is less than 0.5 μm, the surface of the raised regions Ri will be too smooth, making the adhesive of the linerless label more likely to stick to the surface of the raised regions Ri (leading to jams). Conversely, if the arithmetic mean height Sa is greater than 5 μm, the area of ​​the raised regions Ri that contact the linerless label will decrease, reducing the conveying force of the linerless label. Considering the possibility of wear of the raised regions Ri, it is also preferable that the surface roughness (arithmetic mean height Sa) of the recessed regions Rs be within the above range. As the raised regions Ri wear, the contact time and pressure of the linerless label with the recessed regions Rs will increase. Similarly, if the surface of the recessed regions Rs is too smooth, the adhesive of the linerless label will more likely stick to the surface of the recessed regions Rs, while 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.

[0066] Next, the wear visual inspection groove 13 will be described with reference to Figure 8. The platen roller 8 wears over time and, once worn, can no longer maintain its original performance. Therefore, the 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 user of the printer 1 can check the wear visual inspection groove 13 to determine whether the platen roller 8 needs to be replaced.

[0067] Figure 8 is a diagram illustrating the wear visual inspection groove 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 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 perspective of user visibility, it is preferable that the bottom surface of the groove 132 be a glossy surface.

[0068] The visual wear groove 13 is initially 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 are recognized by the user as a single thick line. By positioning the bottom surface of the groove 132 shallower than the reference surface 1210, it is possible to determine the time to replace the convex region Ri before it is completely worn away.

[0069] 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.

[0070] 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. Note that the effect of preventing the flow of electricity is exerted whether the labels are linerless labels or liner-attached labels.

[0071] Additionally, the surface (outer peripheral surface) 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.

[0072] As shown in FIG. 4 , the platen roller 8 described above has both the first elastic member 11 and the second elastic member 12 cylindrical in shape. However, this is not limiting, and each elastic member can have various shapes. For example, in one embodiment, the first elastic member 11 is configured to be tapered at least partially along the axial direction of the roller shaft 10. This allows for stable transport of particularly narrow linerless labels and liner-attached labels. FIG. 9 shows an example in which the first elastic member 11 is tapered at least partially along the axial direction of the first elastic member 11. FIG. 9 is a cross-sectional view of platen rollers 8A to 8D according to modified examples (corresponding to the cross-section of the platen roller 8 shown in FIG. 4 ).

[0073] 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.

[0074] As described 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. Setting these thicknesses increases the overall rubber hardness of the platen roller 8, allowing for increased pressure on the label when the continuous paper is clamped between the thermal head 7 and the platen roller 8, enabling stable printing. Furthermore, 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 transporting relatively narrow linerless labels and liner-attached labels, in particular, it is not necessary to increase the rubber hardness throughout the entire axial length of the roller shaft 10; it is preferable to set the desired rubber hardness in the range where the label passes (the range where the label contacts the platen roller). From this perspective, the diameter of the first elastic material on the inner side of the platen rollers 8A-8D varies along the axis of the roller shaft 10 to achieve locally higher rubber hardness.

[0075] The platen roller 8A shown in FIG. 9 includes a first elastic member 11A attached to the outer periphery of the roller shaft 10 and a second elastic member 12A attached to the outer periphery of the first elastic member 11A. The diameter of the first elastic member 11A 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 a conical outer surface. The platen roller 8A is effective when relatively narrow labels are conveyed by moving them toward 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 labels are conveyed.

[0076] The platen roller 8B in FIG. 9 includes 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. The diameter of the first elastic member 11B 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 peripheral surface 111B-1 whose diameter gradually decreases toward the end face 112BL, based on a position 201 in the axial direction of the roller shaft 10, and a peripheral surface 111B-2 whose diameter is constant. The platen roller 8B is effective when relatively narrow labels are conveyed by moving them toward 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 labels are conveyed.

[0077] The platen roller 8C in FIG. 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. The diameter of the first elastic member 11C 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. That is, 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 relatively narrow labels are transported in the center (the range including position 202). In this case, the rubber hardness can be set high in the area where the labels are transported.

[0078] The platen roller 8D shown in FIG. 9 includes 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. The diameter of the first elastic member 11D 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 of the roller shaft 10. That is, the first elastic member 11D has peripheral surfaces 111D-1 and 111D-3 whose diameters gradually decrease from positions 203 and 204 toward both ends of the roller shaft 10 in the axial direction. A peripheral surface 111D-2 with a constant diameter is formed between positions 203 and 204. The platen roller 8D is effective when relatively narrow labels are transported in the central portion (the range from positions 202 to 204). In this case, the rubber hardness can be set high in the region where the labels are transported.

[0079] 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 continuous paper is stabilized.

[0080] 9, each of the platen rollers 8A to 8D is configured so that the roller shaft 10 does not come into contact with the second elastic members 12A to 12D at both ends. That is, the end faces 112AR to 112DR and the 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.

[0081] 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.

[0082] The present invention is related to patent application No. 2024-51044, filed with the Japan Patent Office on March 27, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. An elastic roller for transporting a belt-shaped member having an adhesive surface while contacting the adhesive surface of the belt-shaped member, comprising: a roller shaft; a first elastic material attached to the outer periphery of the roller shaft; and a second elastic material attached to the outer periphery of the first elastic material, wherein the surface of the second elastic material is provided with an uneven structure having concave and convex regions, and the uneven structure is configured so that a plurality of pattern regions, each having a predetermined shape pattern, are arranged adjacent to each other in the circumferential and axial directions of the roller shaft.

2. An elastic roller according to claim 1, wherein the uneven structure is configured such that a group consisting of a predetermined number of pattern areas, each having a different shape pattern, is repeated in the circumferential and axial directions of the roller shaft, and in each group, the predetermined number of pattern areas are arranged in one direction.

3. An elastic roller according to claim 1 or 2, wherein the proportion of the surface of the second elastic material occupied by the recessed areas is within the range of 45 to 75%, and the proportion of the surface occupied by the raised areas is within the range of 25 to 55%.

4. The elastic roller according to claim 2, wherein the one direction is a direction inclined with respect to the axial direction of the roller shaft.

5. An elastic roller according to claim 2, wherein each of the predetermined number of pattern areas has a predetermined number of element shapes corresponding to a predetermined number of different types of characters, figures or symbols, and each of the predetermined number of element shapes has a shape selected from a plurality of character shapes, figure shapes or symbol shapes of the same type but different shapes.

6. The elastic roller according to claim 5, wherein the element shape in the convex region is configured so as to have no sharp points.

7. The elastic roller according to claim 1 or 2, wherein the arithmetic mean height Sa of the recessed areas and the raised areas is within a range of 0.5 μm to 5 μm.

8. An elastic roller according to any one of claims 1 to 7, wherein the first elastic material is non-conductive and the second elastic material is conductive.

9. An elastic roller according to claim 1 or 2, wherein the second elastic material is formed so as to cover at least a part of the end of the first elastic material in the axial direction of the roller shaft.

10. The elastic roller according to claim 9, wherein the second elastic member is not in contact with the roller shaft.

11. An elastic roller according to claim 1 or 2, 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.

12. An elastic roller according to claim 1 or 2, wherein the first elastic member is at least partially tapered along the axial direction of the roller shaft.

13. An elastic roller as described in claim 1 or 2, wherein a groove for visually checking wear is provided on the surface of the second elastic material, and the groove for visually checking wear has a convex portion protruding from the surface of the second elastic material and a groove formed in the convex portion.

14. The elastic roller according to claim 13, wherein the protrusions are formed in a band shape along the circumferential direction of the roller shaft.

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