Thermal printer

Abstract

To provide a thermal printer which enables maintenance to be performed easily while inhibiting increase of the number of components and deterioration of printing accuracy.SOLUTION: A thermal printer 1 includes: a housing 2; a platen roller 3; a thermal head 4 which is arranged so as to be opposed to the platen roller 3; and a paper guide 5 that is pivotally supported so as to be rotatable around a rotary shaft (a platen shaft 31) relative to the housing 2. The paper guide 5 forms a paper passage 11 for a sheet 10 with the housing 2. Further, the paper guide 5 rotates between a guide position P1 at which the sheet 10 is allowed to be fed between the platen roller 3 and the thermal head 4 and an open position at which the sheet passage 11 for the sheet 10 is exposed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal printer. [Background technology]

[0002] Conventionally, thermal printers have been known in which the printing unit is composed of a thermal head and a platen roller disposed opposite the thermal head. Thermal printers include two types: a clamshell type in which the thermal head and platen roller are separated from each other before paper is loaded when not printing, and then they are brought into contact with each other after paper has been loaded, and an autoloading type in which the distance between the thermal head and platen roller is fixed and paper is inserted between the thermal head and platen roller for printing. Various technologies related to autoloading thermal printers have been proposed, particularly as a method suitable for printing on paper such as labels, whose top of the print area is clearly defined.

[0003] For example, Patent Document 1 discloses a thermal printer having a thermal printer and a platen roller arranged opposite each other with a small gap between them, in which the gap dimension between the thermal printer and the platen roller when not printing is set smaller than the thickness dimension of the paper to be printed. According to the technology described in Patent Document 1, because paper is inserted between the thermal printer and platen roller, which are facing each other with a small gap between them, it is possible to suppress the occurrence of pressure marks on the platen roller and improve print quality compared to when the thermal printer and platen roller are in constant contact. Also, because the gap dimension between the thermal printer and platen roller is smaller than the thickness of the paper, it is possible to print without leaving a margin on the leading edge of the paper in the transport direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-119733 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology described in Patent Document 1, if a paper jam occurs or paper debris accumulates on the paper path from the paper feed slot to the platen roller, it can be difficult to remove these foreign objects. Furthermore, if the paper guide that forms the paper path is made detachable to facilitate maintenance, a fixed part must be installed separately, which can increase the number of parts. Furthermore, if the position of the paper guide shifts before and after maintenance, printing accuracy can be affected. Therefore, in the prior art, there was a problem in improving maintainability while suppressing an increase in the number of parts and a decrease in printing accuracy, particularly in autoloading type thermal printers.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a thermal printer that can be easily maintained while suppressing an increase in the number of parts and a decrease in printing accuracy. [Means for solving the problem]

[0007] In order to solve the above problem, one form of a thermal printer of the present invention includes a housing, a platen roller rotatably supported by the housing, a thermal head housed in the housing and positioned opposite the platen roller, and a paper guide that forms a paper passage path between the housing and the platen roller and is rotatably supported relative to the housing around a rotation axis between a guide position where the paper can be supplied between the platen roller and the thermal head and an open position where the paper passage path for the paper is exposed.

[0008] According to this configuration, when the paper guide is in the guide position, a paper passage path is formed between the housing and the paper guide, allowing paper to be fed between the platen roller and the thermal head through this paper passage path. The paper guide is pivotally supported on the housing between the guide position and the open position. As a result, if a paper jam occurs, for example, the paper guide can be rotated to the open position to expose the paper passage path, making it easy to remove foreign matter. Furthermore, since the paper guide and the housing are positioned relative to each other except for the rotation angle, after removing the foreign matter, the paper guide can be reset to the correct position simply by rotating the paper guide to the guide position around the rotation axis. This makes maintenance easier than, for example, when the paper guide is detachable from the housing. It also reduces the risk of a decrease in printing accuracy due to paper guide misalignment. Furthermore, because paper guide misalignment is less likely to occur, a high-precision design is possible. Furthermore, compared to when the paper guide is detachable, there is no need for dedicated parts for fixing the paper guide, thereby reducing the number of parts required. Therefore, it is possible to provide a thermal printer that can be easily maintained while suppressing an increase in the number of parts and a decrease in printing accuracy.

[0009] In the thermal printer, the rotation shaft is provided coaxially with the platen shaft of the platen roller.

[0010] With this configuration, the platen shaft of the platen roller can be used as the rotation shaft of the paper guide, eliminating the need for a new component as the rotation shaft. This reduces the number of components and improves maintainability. Furthermore, by using the platen shaft of the platen roller, which is installed with high positional accuracy, as the rotation shaft, the positional accuracy of the paper guide when it is installed is also improved. Therefore, even if the paper guide is rotated for maintenance, a decrease in printing accuracy due to the rotation of the paper guide can be reduced.

[0011] In the thermal printer, the paper guide has a snap-fit ​​portion that is fixed to the housing at the guide position.

[0012] With this configuration, the snap-fit ​​portion of the paper guide is attached to the housing, thereby securing the paper guide to the housing. Therefore, after rotating the paper guide to the open position for maintenance, the paper guide can be easily returned to its original mounting position. This further improves maintainability. Furthermore, compared to attaching the paper guide to the housing using fastening members or other fixing parts, for example, the number of parts can be reduced.

[0013] In the thermal printer, the paper guide has a guide roller that feeds the paper between the platen roller and the thermal head.

[0014] With this configuration, the guide roller of the paper guide more reliably feeds paper through the paper path to between the platen roller and the thermal head. This allows for effective paper feeding between the platen roller and the thermal head. Because the guide roller is attached to the paper guide, the guide roller can be exposed by rotating the guide roller to the open position. Therefore, even if, for example, paper debris gets caught between the guide rollers, this foreign matter can be easily removed. This improves maintainability compared to conventional technologies in which the guide roller cannot be exposed. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a thermal printer that allows easy maintenance while suppressing an increase in the number of parts and a decrease in printing accuracy. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view showing a state in which the paper guide is at a guide position in the thermal printer according to the embodiment. [Figure 2] FIG. 2 is a perspective view showing a state in which the paper guide is in an open position in the thermal printer according to the embodiment. [Figure 3]FIG. 2 is a rear perspective view showing the thermal printer according to the embodiment, in a state where the paper guide is in a guide position. [Figure 4] FIG. 2 is a rear perspective view showing a state in which the paper guide is in an open position in the thermal printer according to the embodiment. [Figure 5] 4 is a cross-sectional view taken along line VV in FIG. 3. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 4. [Figure 7] FIG. 4 is a perspective view showing the state in which the platen roller and the paper guide are attached. [Figure 8] FIG. 10 is a cross-sectional view showing the configuration of the snap-fit ​​portion as viewed from the front in the paper transport direction. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of these components may be omitted. In the drawings, FR indicates the front, LH indicates the left, and UP indicates the top. Note that the "front" refers to the front in the transport direction of paper 10 supplied to the thermal printer 1.

[0018] (thermal printer) FIG. 1 is a perspective view of the thermal printer 1 according to the embodiment, showing the paper guide 5 in a state where it is in a guide position P1. FIG. 2 is a perspective view of the thermal printer 1 according to the embodiment, showing the paper guide 5 in an open position P2. FIG. 3 is a rear perspective view of the thermal printer 1 according to the embodiment, showing the paper guide 5 in a state where it is in a guide position P1. FIG. 4 is a rear perspective view of the thermal printer 1 according to the embodiment, showing the paper guide 5 in an open position P2.

[0019] The thermal printer 1 of this embodiment is used by being placed on a desk, floor, or the like. Therefore, in this embodiment, the thermal printer 1 will be described as being placed on a desk, floor, or the like as shown in FIG. 1. The thermal printer 1 may also be carried by a user for use. In this case, the thermal printer 1 may be used in a position where the front side in FIG. 1 faces upward or downward, for example. As shown in FIGS. 1 to 4, the thermal printer 1 includes a housing 2, a platen roller 3, a thermal head 4, and a paper guide 5.

[0020] The housing 2 has a bottom wall 20, a pair of left and right side walls 21, a rear wall 22, and an upper wall 23, and is formed in a box shape with openings at the front top and front portion. The housing 2 is made of a resin material such as polycarbonate, a metal material, or the like. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 4.

[0021] 5 and 6, the top wall 23 has a bulging portion 36 that bulges outward from the upper end of the rear wall 22, becoming convex upward as it extends forward, and a forward extending portion 37 that extends forward from the front end of the bulging portion 36. The paper 10 (see FIG. 1) to be printed is transported along the top wall 23. A sensor 28 for detecting the position of the leading edge of the transported paper 10 is provided on the top wall 23 near the platen roller 3. In this embodiment, the paper 10 to be printed is thermal paper, such as various labels or stickers. A drive motor 25 is housed in the space surrounded by the rear wall 22, bottom wall 20, and top wall 23.

[0022] FIG. 7 is a perspective view showing the state in which the platen roller 3 and the paper guide 5 are attached. As shown in Figures 1 and 2, a platen shaft 31 of the platen roller 3 is suspended from the upper front end of the pair of left and right side walls 21. The platen shaft 31 is fixed to the pair of left and right side walls 21 and extends in the left-right direction. As shown in Figures 1, 2 and 7, the platen roller 3 is rotatably supported on the outer periphery of the platen shaft 31. The platen roller 3 is driven to rotate by receiving driving force from a drive motor 25.

[0023] As shown in Figures 1 and 5, a line-type thermal head 4 is disposed below the platen roller 3, facing and substantially parallel to the platen roller 3. The thermal head 4 has a plurality of heating elements aligned in the left-right direction on a metal substrate. As shown in Figure 5, the thermal head 4 is attached to the tip (one end) of a bracket 41, one end of which is swingable relative to the housing 2. The thermal head 4 is constantly biased toward the platen roller 3 by a biasing member 45 provided between the thermal head 4 and the housing 2. Therefore, when no paper 10 is set and no printing is being performed, the platen roller 3 and the thermal head 4 are in contact with each other. When paper 10 is set and printing is being performed, the platen roller 3 and the thermal head 4 are pressed against each other with the paper 10 sandwiched between them.

[0024] 1 and 7, the paper guide 5 is located at the top front of the housing 2, near the platen roller 3. The paper guide 5 is rotatably supported on the platen shaft 31 via bearings 33 provided on both the left and right sides of the platen shaft 31. As a result, the paper guide 5 is rotatably supported on the housing 2 around the rotation axis (i.e., the platen shaft 31). In other words, the rotation axis of the paper guide 5 is arranged coaxially with the platen shaft 31. Note that the bearings 33 are preferably configured so that the platen shaft 31 and the platen roller 3 do not rotate together when the paper guide 5 rotates.

[0025] The paper guide 5 is rotatable between a guide position P1, which is the state that is mainly used during printing as shown in Figures 1, 3, and 5, and an open position P2, which is the state that is mainly used during maintenance as shown in Figures 2, 4, and 6. As shown in Figure 5, the underside of the paper guide 5 at guide position P1 is formed into a curved shape that is convex downward (see also Figure 4).

[0026] 1 and 5, when the paper guide 5 is in guide position P1, the paper guide 5 forms a paper passage path 11 for the paper 10 between itself and the housing 2. The paper passage path 11 guides the paper 10 inserted from the rear along the upper wall 23 to between the platen roller 3 and the thermal head 4. By inserting the paper 10 between the platen roller 3 and the thermal head 4 through this paper passage path 11, it becomes possible to print on the paper 10.

[0027] 2 and 6, by lifting the rear end of the paper guide 5 upward, the paper guide 5 can be rotated to an open position P2, where the rear end of the paper guide 5 is positioned above the guide position P1. The open position P2 is rotated approximately 90 degrees from the guide position P1. By rotating the paper guide 5 to the open position P2, the paper passage path 11 for the paper 10 is exposed. Here, the state in which the paper passage path 11 is exposed refers to a state in which the paper passage path 11 is exposed to the extent that the front side of the platen roller 3 in the conveyance direction can be seen when a user looks from above, for example (see FIG. 4). This makes it possible to visually check for foreign matter in the event of a paper jam or accumulation of paper 10 debris and quickly remove the foreign matter.

[0028] As shown in Figures 4 and 5, the paper guide 5 has multiple guide rollers 51, 52 (two in this embodiment) that supply the paper 10 between the platen roller 3 and the thermal head 4 at guide position P1. The two guide rollers 51, 52 are located at the rear and front of the paper 10 in the transport direction at guide position P1. The two guide rollers 51, 52 are each rotatable relative to the paper guide 5. As shown in Figure 5, the rear guide roller 51 is located at the rear end of the lower surface of the paper guide 5 at guide position P1. As shown in Figure 4, the rear guide roller 51 is located approximately in the center in the left-right direction and is shorter than the left-right length of the paper guide 5.

[0029] As shown in Fig. 5, the front guide roller 52 is located on the underside of the paper guide 5 at guide position P1, closer to the platen roller 3 than the rear guide roller 51. As shown in Fig. 4, the front guide roller 52 is located approximately in the center in the left-right direction, and is formed to be even shorter than the rear guide roller 51. The outer periphery of each guide roller 51, 52 is provided with protrusions 51a, 52a to facilitate transport of the paper 10 while preventing the paper 10 from sticking to the paper guide 5.

[0030] FIG. 8 is a cross-sectional view showing the configuration of the snap-fit ​​portion 53 as seen from the front in the conveyance direction of the paper 10. As shown in Figures 3, 4, and 8, the paper guide 5 has a pair of snap-fit ​​portions 53 at its left and right ends. The left and right snap-fit ​​portions 53 are symmetrical, so the following explanation will use the left snap-fit ​​portion 53 as an example. As shown in Figure 8, the snap-fit ​​portion 53 has a connecting portion 54 connected to the paper guide body, an extension portion 55 extending from the connecting portion 54 toward the underside of the paper guide 5, a locking claw 56 provided at the tip of the extension portion 55, and a grip portion 57 provided at the base end of the extension portion 55.

[0031] Furthermore, locking portions 27 are provided on the pair of side walls 21 of the housing 2 at positions corresponding to the snap-fit ​​portions 53. The locking portions 27 are holes into which the extension portions 55 of the snap-fit ​​portions 53 are inserted and into which the locking claws 56 engage, for example, at guide position P1. Therefore, when the paper guide 5 is rotated from the open position P2 to the guide position P1, the snap-fit ​​portions 53 are locked with the locking portions 27, thereby fixing the paper guide 5 to the housing 2. To release the engagement, the gripping portions 57 are pressed inward in the left-right direction, which releases the engagement of the locking claws 56 and allows the paper guide 5 to be rotated.

[0032] (Action, effect) Next, the operation and effects of the thermal printer 1 described above will be described. The thermal printer 1 of this embodiment includes a housing 2, a platen roller 3, a thermal head 4, and a paper guide 5. The paper guide 5 is pivotally supported on the housing 2 between a guide position P1 and an open position P2, rotatably about a pivot shaft. With this configuration, when the paper guide 5 is in the guide position P1, a paper passage path 11 is formed between the housing 2 and the paper guide 5. Paper 10 can be fed through this paper passage path 11 to between the platen roller 3 and the thermal head 4. The paper guide 5 is pivotally supported on the housing 2 between the guide position P1 and the open position P2. This allows, for example, if a paper jam occurs, the paper guide 5 can be rotated to the open position P2 to expose the paper passage path 11, making it easy to remove foreign matter. Furthermore, because the paper guide 5 and the housing 2 are positioned relative to each other except for the rotation angle, after removing the foreign matter, the paper guide 5 can be reset to the correct position simply by rotating the paper guide 5 to the guide position P1 about the pivot shaft. Therefore, maintenance can be performed more easily compared to, for example, a case in which the paper guide 5 is configured to be detachable from the housing 2. Also, a decrease in printing accuracy due to misalignment of the paper guide 5 can be suppressed. Furthermore, because misalignment of the paper guide 5 is less likely to occur, a highly accurate design can be achieved. Also, compared to a case in which the paper guide 5 is configured to be detachable, there is no need to provide dedicated parts for fixing, so an increase in the number of parts can be suppressed. Therefore, it is possible to provide a thermal printer 1 that can be easily maintained while suppressing an increase in the number of parts and a decrease in printing accuracy.

[0033] The rotation axis of the paper guide 5 is provided coaxially with the platen shaft 31 of the platen roller 3. With this configuration, the platen shaft 31 of the platen roller 3 can be used as the rotation axis of the paper guide 5, eliminating the need for a new part as the rotation axis. This improves maintainability while minimizing an increase in the number of parts. Furthermore, by using the platen shaft 31 of the platen roller 3, which is attached with high positional accuracy, as the rotation axis, the positional accuracy of the paper guide 5 when it is attached is also improved. Therefore, even if the paper guide 5 is rotated for maintenance, a decrease in printing accuracy due to the rotation of the paper guide 5 can be suppressed.

[0034] The paper guide 5 has a snap-fit ​​portion 53 that is fixed to the housing 2 at the guide position P1. With this configuration, the snap-fit ​​portion 53 of the paper guide 5 is attached to the housing 2, thereby fixing the paper guide 5 to the housing 2. Therefore, after rotating the paper guide 5 to the open position P2 for maintenance, the paper guide 5 can be easily returned to its original attached position. This further improves maintainability. Also, compared to attaching the paper guide 5 to the housing 2 using, for example, fastening members or other fixing parts, the increase in the number of parts can be suppressed.

[0035] The paper guide 5 has guide rollers 51 and 52 that supply the paper 10 between the platen roller 3 and the thermal head 4. With this configuration, the guide rollers 51 and 52 of the paper guide 5 more reliably supply the paper 10 between the platen roller 3 and the thermal head 4 through the paper passage 11. This allows the paper 10 to be effectively supplied between the platen roller 3 and the thermal head 4. Because the guide rollers 51 and 52 are attached to the paper guide 5, the guide roller portions can be exposed by rotating the guide rollers 51 and 52 to the open position P2. Therefore, even if, for example, scraps of paper 10 become caught between the guide rollers 51 and 52, these foreign objects can be easily removed. This improves maintainability compared to conventional technology in which the guide roller portions cannot be exposed.

[0036] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although not shown in the above embodiment, a cover member or the like may be provided on the outside of the housing 2. In this case, an operation unit (not shown) for performing various operations on the thermal printer 1 may be provided on the cover member. Examples of the operation unit include a switch and a lamp.

[0037] The outer peripheries of the guide rollers 51 and 52 may be provided with, for example, convex portions, claw portions, surface-treated surfaces, etc., instead of the protrusions 51a and 52a. In the above embodiment, the sensor 28 for detecting the leading edge position of the paper sheet 10 is provided on the upper wall 23 of the housing 2, but the present invention is not limited to this. A sensor for detecting the leading edge position of the paper sheet 10 may also be provided on the underside of the paper guide 5.

[0038] In addition, within the scope of the spirit of the present invention, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments may be combined as appropriate. [Explanation of symbols]

[0039] 1. Thermal printer 2. Case 3 Platen roller 4 Thermal head 5 Paper Guide 10 Paper 11 Paper path 31 Platen shaft (rotating shaft) 51 Rear guide roller (guide roller) 52 Front guide roller (guide roller) 53 Snap fit part P1 Guide position P2 open position

Claims

1. The housing and a platen roller rotatably supported by the housing; a thermal head accommodated in the housing and disposed opposite the platen roller; a paper guide that forms a paper passage path between itself and the housing, and is pivotally supported relative to the housing around a pivot shaft between a guide position where the paper can be supplied between the platen roller and the thermal head and an open position where the paper passage path of the paper is exposed; A thermal printer comprising:

2. The rotation shaft is provided coaxially with a platen shaft of the platen roller.

2. The thermal printer according to claim 1.

3. The paper guide has a snap-fit ​​portion that is fixed to the housing at the guide position.

3. The thermal printer according to claim 1 or 2.

4. the paper guide has a guide roller that supplies the paper between the platen roller and the thermal head; 3. The thermal printer according to claim 1 or 2.

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