JP2023122468A - Printing device - Google Patents

Abstract

To enhance reliability on operation of drawing a printing medium into a gap between a thermal head and a platen roller.SOLUTION: A printing device comprises: a thermal head 11; a platen roller 12; a head support plate 13; a turning shaft that turnably supports the head support plate; an operating shaft having an operating part that turns the head support plate around the turning shaft; a roller shaft 19 supporting the platen roller; and a pair of side plates which have first support holes supporting the turning shaft, second support holes supporting the operating shaft and third support holes supporting the roller shaft. The head support plate has a flat head support surface, formed along a printing surface of the thermal head, which contacts the thermal head, and a pair of support pieces 13b supported on the turning shaft. In each support piece, is formed a shaft hole 13c through which the turning shaft is inserted. The shaft hole is formed in a long hole shape extending in a direction orthogonal to the head support surface, from the head support surface, where the turning shaft is supported on the shaft hole while contacting the head support surface.SELECTED DRAWING: Figure 6

Description

The present invention relates to a printing device.

A printing apparatus is known that includes a thermal head that prints on a sheet-like print medium, and a platen roller that feeds the print medium while sandwiching it between the thermal head and the thermal head.

In this type of printing apparatus, when the print medium pulled out from the supply roll is fed to the take-up roll along the transport path of the print medium, the front end of the print medium pulled out from the supply roll is shaped like a U. Some print media are fed from one end of the transport path by rotation of a platen roller. In this printing apparatus, the rotation of the platen roller draws the front end of the print medium bent along the transport path so as to pass through the minute gap between the thermal head and the platen roller.

JP 2017-35803 A

In the above-described printing apparatus, for example, the gap between the thermal head and the platen roller may become large due to variations in dimensional tolerance of the rotating structure of the head support plate that supports the thermal head. In such a case, the print medium is less likely to come into contact with the peripheral surface of the platen roller, and the platen roller idles when pulling in the print medium, allowing the print medium to move smoothly between the platen roller and the thermal head. cannot be drawn into As a result, the printer has a problem that it becomes difficult to pass the print medium along the transport path.

The disclosed technique has been made in view of the above, and aims to improve the dimensional accuracy of the gap between the thermal head and the platen roller and improve the reliability of the operation of pulling the print medium into the gap between the thermal head and the platen roller. It is an object of the present invention to provide a printer capable of

One aspect of the printing apparatus disclosed in the present application includes a thermal head that prints on a sheet-like print medium, a platen roller that feeds the print medium while sandwiching it between the thermal head, and a head support plate that supports the thermal head. an operation having a rotation shaft for rotatably supporting the head support plate in a direction for advancing and retracting the thermal head with respect to the platen roller; and an operating portion for rotating the head support plate about the rotation shaft. a shaft, a roller shaft that rotatably supports the platen roller, a first support hole that supports the rotation shaft, a second support hole that supports the operating shaft, and a third support that supports the roller shaft and a pair of side plates having holes, wherein the head support plate is supported by a flat head support surface formed along the printing surface of the thermal head and in contact with the thermal head, and the rotary shaft. and a pair of support pieces, each of which is formed with a shaft hole through which the rotation shaft passes, and the shaft hole extends from the head support surface in a direction orthogonal to the head support surface. The rotary shaft is supported in the shaft hole in contact with the head support surface.

According to one aspect of the printing apparatus disclosed in the present application, it is possible to improve the dimensional accuracy of the gap between the thermal head and the platen roller, and improve the reliability of the operation of pulling the print medium into the gap between the thermal head and the platen roller.

FIG. 1 is a schematic diagram showing an outline of a printer according to an embodiment. FIG. 2 is a perspective view showing the printing section of the printing device of the embodiment. FIG. 3 is a perspective view showing the printing section of the printing device of the embodiment from another direction. FIG. 4 is a perspective view showing the essential part of the printing unit in the embodiment. FIG. 5 is a perspective view showing the head support plate in the embodiment. FIG. 6 is a side view showing the shaft hole of the head support plate in the embodiment. FIG. 7 is a side view for explaining the side plate in the example. FIG. 8 is an enlarged sectional view for explaining the gap between the thermal head and the platen roller in the embodiment.

An embodiment of the printing apparatus disclosed in the present application will be described in detail below with reference to the drawings. It should be noted that the printing apparatus disclosed in the present application is not limited to the following embodiments.

FIG. 1 is a schematic diagram showing an outline of a printer according to an embodiment. As shown in FIG. 1, the printing apparatus 1 of the embodiment includes a printing unit 5 for printing on a sheet-like printing medium 3 and a conveying unit 6 for conveying the printing medium 3 to the printing unit 5. . The print medium 3 is, for example, thermal paper or thermal film, and has a thickness of about 0.07 [mm] to 0.06 [mm].

As shown in FIG. 1, the depth direction of the printer 1 (horizontal direction in which the supply roll 22 and the take-up roll 23, which will be described later) are aligned, is defined as the X direction, and the width direction of the printer 1 (the axial direction of the platen roller 12, which will be described later). is the Y direction, and the height direction of the printer 1 is the Z direction. As in FIG. 1, each drawing shows the X, Y, and Z directions.

FIG. 2 is a perspective view showing the printing section 5 of the printing device 1 of the embodiment. FIG. 3 is a perspective view showing the printing section 5 of the printing device 1 of the embodiment from another direction. FIG. 4 is a perspective view showing a main portion of the printing section 5 in the embodiment.

As shown in FIGS. 2, 3, and 4, the printing unit 5 of the printing device 1 includes a thermal head 11 that prints on the printing medium 3, and a platen roller 12 that feeds the printing medium 3 while sandwiching it between the thermal heads 11. and a head support plate 13 that supports the thermal head 11 . The printing unit 5 also sandwiches the compression coil springs 15 between a pair of compression coil springs 15 that press the thermal head 11 supported by the head support plate 13 toward the platen roller 12 and the head support plate 13 . and a bracket member 16 .

The printing unit 5 also includes a rotary shaft 17 that rotatably supports the head support plate 13 in a direction to move the thermal head 11 forward and backward with respect to the platen roller 12 , and a rotary shaft 17 that rotates the head support plate 13 around the rotary shaft 17 . An operating shaft 18 having an operating portion 18a to be moved and a roller shaft 19 rotatably supporting the platen roller 12 are provided. The printing unit 5 also includes a pair of side plates 20 that respectively support the rotation shaft 17, the operating shaft 18, and the roller shaft 19, a roller driving mechanism (not shown) that rotationally drives the roller shaft 19 of the platen roller 12, Prepare.

As shown in FIG. 1, the transport unit 6 of the printing apparatus 1 includes a supply roll 22 that supplies the print medium 3, and the print medium 3 supplied from the supply roll 22 and passed between the thermal head 11 and the platen roller 12. a take-up roll 23 on which the print medium 3 is taken up, a guide member 24 forming a U-shaped transport path 24a that feeds the print medium 3 pulled out from the supply roll 22 between the thermal head 11 and the platen roller 12, and a take-up and a winding mechanism (not shown) that rotates the roll 23 .

As shown in FIG. 1, the transport path 24a of the guide member 24 extends in one direction from the supply roll 22 toward the printing unit 5 when viewed from the axial direction (Y direction) of the roller shaft 19 of the platen roller 12. The direction of travel of the print medium 3 is changed to the opposite direction of the one direction, that is, the other direction of travel from the printing unit 5 to the take-up roll 23 side, so that the print medium 3 moves between the thermal head 11 and the platen roller 12. It is formed in a substantially U-shape passing through the gap between (see FIG. 8).

As described above, the transport path 24a in this embodiment is formed in a substantially U-shape, so that the print medium 3 curved along the transport path 24a is slightly separated between the thermal head 11 and the platen roller 12. High dimensional accuracy is required for this gap in order to pass through the gap.

In addition, the transport path 24a has a flat portion F at one end where the print medium 3 pulled out from the supply roll 22 enters and into which the print medium 3 is linearly inserted into the transport path 24a. As a result, when the print medium 3 is passed along the transport path 24a, the front end of the print medium 3 pulled out from the supply roll 22 is inserted along the flat portion F of the transport path 24a. 24a can be smoothly inserted.

Further, the transport path 24a is provided with a detection unit 25 for detecting the front end of the print medium 3 pulled out from the supply roll 22 and inserted from the lower end of the transport path 24a. Although not shown, for example, it has a light-emitting portion that emits detection light and a light-receiving portion that receives the detection light from the light-emitting portion, and the width direction (Y direction) are provided with a light emitting portion and a light receiving portion. The detection unit 25 is connected to a control unit (not shown) and sends a detection signal for detecting the leading edge of the print medium 3 to the control unit. The control unit controls to drive the roller drive mechanism based on the detection signal from the detection unit 25 , rotates the platen roller 12 , and conveys the print medium 3 .

(Main part of printer)
FIG. 5 is a perspective view showing the head support plate 13 in the embodiment. FIG. 6 is a side view showing shaft holes of the head support plate 13 in the embodiment.

As shown in FIG. 5, the head support plate 13 of the printing unit 5 has a flat head support surface 13a in contact with the thermal head 11 and a pair of support pieces 13b supported by the rotary shaft 17. As shown in FIG. The head supporting surface 13a is formed along the printing surface 11a of the thermal head 11 and substantially parallel to the printing surface 11a.

A shaft hole 13c through which the rotating shaft 17 is passed is formed in each support piece 13b. As shown in FIG. 6, the shaft hole 13c is formed in the shape of an elongated hole extending from the head support surface 13a in a direction perpendicular to the head support surface 13a. It is supported within hole 13c. The rotating shaft 17 is supported in the shaft hole 13c in contact with both sides of the shaft hole 13c in the minor axis direction.

The head support surface 13a also functions as a reference plane serving as a machining reference for the shaft hole 13c. As shown in FIG. 6, on a plane (XZ plane) perpendicular to the axial direction of the rotating shaft 17, the shaft hole 13c of the head support plate 13 is positioned with respect to the head support surface 13a with the head support surface 13a as a processing reference. , and the center O of the rotary shaft 17 in contact with the head support surface 13a is the dimension A, and the shaft hole 13c is formed in an elongated shape with a slight amount of play in the longitudinal direction.

The long hole-shaped shaft hole 13c in the present disclosure is a long hole in which a slight amount of play is ensured in order to suppress the influence of the dimensional tolerance of the shaft hole 13c. The technical idea is different from the long hole in the broad sense of . For example, when the shaft diameter of the rotating shaft 17 is 3.0 [mm], a shaft hole extending in the longitudinal direction of the shaft hole 13c (direction perpendicular to the head support surface 13a) with respect to the shaft diameter of the rotating shaft 17 The play amount of 13c is set to 0.1 [mm] or less. That is, the play amount of the shaft hole 13c is set to 1/30 or less of the shaft diameter of the rotating shaft 17. As shown in FIG. In other words, the shaft hole 13c is formed in an elongated shape extending in a direction orthogonal to the head support surface 13a with a play amount that is approximately the same as the dimensional tolerance when forming a circular shaft hole.

By forming the shaft hole 13c in the shape of an elongated hole extending from the head support surface 13a in this way, it is possible to form the head support surface 13a as a reference surface. Since the rotary shaft 17 is supported in contact with the head support surface 13a in the shaft hole 13c, it is possible to avoid a change in the state of support via the rotary shaft 17 due to variations in the dimensional tolerance of the shaft hole 13c. In other words, since the rotary shaft 17 is in contact with the head support surface 13a and is supported in the shaft hole 13c, variations in the dimensional tolerance of the shaft hole 13c can be absorbed by play in the longitudinal direction of the elongated shaft hole 13c. This makes it possible to avoid the influence of the dimensional tolerance of the shaft hole 13c on the support state of the rotating shaft 17 by the shaft hole 13c.

In other words, when the shaft hole 13c of the support piece 13b is formed as a perfect circle, that is, a so-called round hole, variations occur according to the dimensional tolerance of the shaft hole 13c due to the machining accuracy of the shaft hole 13c. The positions of the shaft holes 13c of 13b are likely to shift in the direction orthogonal to the head supporting surface 13a. When the positions of the shaft holes 13c of the pair of support pieces 13b are displaced from each other, the support state of the head support plate 13 by the rotating shaft 17 becomes uneven on both sides of the rotating shaft 17 in the axial direction, and the head is not supported. The surface 13a is inclined, and the dimensional accuracy of the gap between the thermal head 11 and the platen roller 12 is lowered. On the other hand, the shaft hole 13c in this embodiment is formed in the shape of an elongated hole extending from the head supporting surface 13a, so that the dimensional accuracy of the gap between the thermal head 11 and the platen roller 12 can be improved.

When the head support plate 13 is rotated around the rotary shaft 17 by the operating portion 18a of the operating shaft 18 and the thermal head 11 is moved toward the platen roller 12, the thermal head 11 and the platen roller 12 are brought into contact with each other. The gap between has a predetermined dimension. This gap is a gap in the radial direction of the platen roller 12 . The predetermined dimension of the gap (see gap G shown in FIG. 8) in the embodiment is set in the range of 0 to 0.4 or less, and the thickness of the print medium 3 to be used (approximately 0.06 [mm] to 0.06 [mm]). 07 [mm]).

Further, the head support plate 13 has a contact portion 13d with which the operating shaft 18 contacts, and the contact portion 13d is formed flat and continuous with the head support surface 13a. In this way, the contact portion 13d of the head support plate 13 is formed flat without being subjected to processing such as bending, for example. can be suppressed, and the accuracy of the forward/backward movement of the head support plate 13 associated with the contact of the operating portion 18a of the operating shaft 18 can be enhanced. As a result, the dimensional accuracy of the gap between the thermal head 11 and the platen roller 12 is further enhanced.

Further, the head support plate 13 has an opening 13e passing through the head support surface 13a and a notch 13f formed by cutting the outer periphery of the head support surface 13a. The opening 13e is provided in the center of the head support surface 13a and positioned in the center of the thermal head 11 in the longitudinal direction (Y direction). The cutouts 13f are formed on both sides of the head support surface 13a across the opening 13e, and are positioned on both sides of the thermal head 11 in the longitudinal direction (Y direction). Further, the head support plate 13 is provided with a positioning piece 13g for positioning the thermal head 11 in contact with the head support surface 13a.

As a result, the rigidity of the head support surface 13a portion of the head support plate 13 is appropriately reduced, and the head support surface 13a can be easily bent along the outer peripheral surface of the thermal head 11. FIG. Therefore, the head support surface 13 a can be in contact with the outer peripheral surface of the thermal head 11 in the entirety of the head support surface 13 a following the thermal head 11 . Therefore, the head support plate 13 prevents the formation of a gap between the head support surface 13 a and the outer peripheral surface of the thermal head 11 . It becomes possible to press the thermal head 11 against the platen roller 12 in the longitudinal direction. As a result, it is possible to suppress the occurrence of faint printing or the like due to non-uniform contact between the print medium 3 and the thermal head 11 .

The head support plate 13 is not limited to a structure having both the opening 13e and the notch 13f. A structure having only one of 13f may be used.

The actuating portion 18a of the actuating shaft 18 has, for example, a rectangular cross-sectional shape perpendicular to the axial direction of the actuating shaft 18, and the size of the actuating shaft 18 changes in the radial direction as the actuating shaft 18 rotates. is formed to The operating shaft 18 is provided so that the operating portion 18a contacts the head support plate 13. As the operating portion 18a rotates, the head support plate 13 rotates around the rotation shaft 17, thereby moving the head support plate. The thermal head 11 supported by 13 advances and retreats toward and away from the platen roller 12 . That is, the operating portion 18a is formed in a shape eccentric with respect to the radial direction of the operating shaft 18, that is, in a cam shape.

As shown in FIG. 4, the bracket member 16 has a pair of support pieces 16a supported by the rotary shaft 17. It is arranged on the outer side of the rotating shaft 17 in the axial direction.

FIG. 7 is a side view for explaining the side plate 20 in the embodiment. Each side plate 20 constitutes a frame member that supports the printing unit 5 and the conveying unit 6 in the printing device 1. As shown in FIG. 18 and a third support hole 28 for supporting the roller shaft 19 .

Thus, by forming three support holes, that is, the first support hole 26, the second support hole 27, and the third support hole 28, in one side plate 20, for example, three support holes can be formed into one side plate. Compared to a structure in which a plurality of frame members with support holes formed therein are not formed in 20, the dimensional accuracy of the relative distances D1, D2, D3, and D4 of the three support holes can be improved. As a result, the dimensional accuracy of the gap between the thermal head 11 and the platen roller 12 is improved, and a synergistic effect is obtained with the effect of reducing variations in the state of support of the rotating shaft 17 by the shaft hole 13c.

The roller shaft 19 is supported in the third support holes 28 via the bearing members, for example, by fitting bearing members provided on both axial sides of the roller shaft 19 into the third support holes 28 .

(Pull-in operation of print medium)
The operation of drawing the print medium 3 along the transport path 24a in the printing apparatus 1 configured as described above will be described. FIG. 8 is an enlarged sectional view for explaining the gap between the thermal head 11 and the platen roller 12 in the embodiment.

As shown in FIGS. 1 and 8, when the print medium 3 is passed from the supply roll 22 to the take-up roll 23, the front end of the print medium 3 pulled out from the supply roll 22 is placed along the flat portion F of the transport path 24a. manually by the user. Subsequently, the printer 1 detects the front end of the print medium 3 inserted into the transport path 24 a by the detection section 25 , and the control section drives the platen roller 12 based on the detection signal of the detection section 25 . As the platen roller 12 rotates, the print medium 3 inserted into the transport path 24a is sent to the thermal head 11 side along the transport path 24a by the platen roller 12 .

As the platen roller 12 rotates, the front end of the print medium 3 sent to the thermal head 11 side passes through the gap G between the thermal head 11 and the platen roller 12 and is sent to the take-up roll 23 side. Finally, the user manually attaches the front end of the print medium 3 sent to the take-up roll 23 side to the take-up roll 23 , so that the thermal head 11 and the platen roller 12 move from the supply roll 22 to the take-up roll 23 . The print medium 3 is stretched so as to pass through the gap G between .

(Effect of Example)
As described above, the printing apparatus 1 of the embodiment includes the rotary shaft 17 that rotatably supports the head support plate 13, the operating shaft 18 that rotates the head support plate 13 around the rotary shaft 17, and the platen roller. 12, a first support hole 26 that supports the rotating shaft 17, a second support hole 27 that supports the operating shaft 18, and a third support hole 28 that supports the roller shaft 19. A pair of side plates 20 are provided. The shaft hole 13c of the head support plate 13 is formed in an elongated shape extending from the head support surface 13A in a direction orthogonal to the head support surface 13a, and the rotary shaft 17 is supported in contact with the head support surface 13a. As a result, the reduction in dimensional accuracy of the rotating structure of the head support plate 13 due to the machining accuracy of the shaft hole 13c of the head support plate 13 can be suppressed, and the first support hole 26 and the second support hole in the side plate 20 can be 27, a synergistic effect with improving the dimensional accuracy of each relative position of the third support hole 28 can be obtained. Due to this synergistic effect, the dimensional accuracy of the gap G between the thermal head 11 and the platen roller 12 can be improved. As a result, the reliability of the operation of pulling the print medium 3 into the gap G between the thermal head 11 and the platen roller 12 can be enhanced.

The printing apparatus 1 of the embodiment also includes a substantially U-shaped transport path 24 a for transporting the print medium 3 to the gap G between the thermal head 11 and the platen roller 12 . The conveying path 24a changes the traveling direction of the printing medium 3, which advances in one direction, to the opposite direction, and the printing medium 3 passes through the gap G between the thermal head 11 and the platen roller 12. It is formed in a U shape. In this way, especially in the structure in which the transport path 24 a of the print medium 3 is folded back in a substantially U shape, the front end of the print medium 3 curved along the transport path 24 a is placed in the gap between the thermal head 11 and the platen roller 12 . Therefore, by increasing the dimensional accuracy of the gap G between the thermal head 11 and the platen roller 12 as in the present embodiment, the effect of improving the reliability of the operation of pulling the print medium 3 is greatly obtained. be done.

The head support plate 13 in the printer 1 of the embodiment has a contact portion 13d with which the operating shaft 18 is in contact, and the contact portion 13d is flat and continuous with the head support surface 13a. Since the contact portion 13d is formed flat without being subjected to processing such as bending, variation in processing dimensions due to processing of the contact portion 13d can be suppressed, and the head support plate 13 by the operating shaft 18 can be controlled. It is possible to improve the accuracy of the forward/backward movement of the. As a result, the dimensional accuracy of the gap G between the thermal head 11 and the platen roller 12 can be further improved.

Further, the head support plate 13 in the printer 1 of the embodiment has an opening 13e penetrating the head support surface 13a and a notch 13f formed by cutting the outer circumference of the head support surface 13a. As a result, the rigidity of the head support surface 13a portion of the head support plate 13 is appropriately lowered, the head support surface 13a is easily bent along the outer peripheral surface of the thermal head 11, and the space between the head support surface 13a and the thermal head 11 is reduced. It is possible to suppress the formation of voids in the Therefore, the thermal head 11 can be pressed against the platen roller 12 in the longitudinal direction of the thermal head 11 by the compression coil spring 15, and the uneven contact state between the print medium 3 and the thermal head 11 can prevent faint printing. occurrence can be suppressed.

Reference Signs List 1 printing device 3 printing medium 5 printing unit 11 thermal head 12 platen roller 13 head support plate 13a head support surface 13b support piece 13c shaft hole 13d contact portion 13e opening 13f notch 17 rotating shaft 18 operating shaft 18a operating portion 19 Roller shaft 20 Side plate 24 Guide member 24a Conveyance path 26 First support hole 27 Second support hole 28 Third support hole F Flat portion G Gap

Claims (5)

a thermal head that prints on a sheet-like print medium;
a platen roller that feeds a print medium sandwiched between it and the thermal head;
a head support plate that supports the thermal head;
a rotation shaft that rotatably supports the head support plate in a direction in which the thermal head advances and retreats with respect to the platen roller;
an operating shaft having an operating portion for rotating the head support plate around the rotating shaft;
a roller shaft that rotatably supports the platen roller;
a pair of side plates having a first support hole that supports the rotating shaft, a second support hole that supports the operating shaft, and a third support hole that supports the roller shaft;
The head support plate has a flat head support surface formed along the printing surface of the thermal head and in contact with the thermal head, and a pair of support pieces supported by the rotation shaft,
Each support piece is formed with a shaft hole through which the rotation shaft passes,
The shaft hole is formed in a long hole shape extending from the head support surface in a direction perpendicular to the head support surface, and the rotating shaft is supported in the shaft hole while being in contact with the head support surface. . further comprising a U-shaped transport path for transporting the print medium between the thermal head and the platen roller;
The conveying path has a U-shape in which the printing medium traveling in one direction is changed to a direction opposite to the one direction so that the printing medium passes between the thermal head and the platen roller. formed to
The printing device according to claim 1. The head support plate has a contact portion with which the operating shaft contacts,
The contact portion is formed in a flat shape continuous with the head support surface,
3. The printer according to claim 1 or 2. The axial hole has an amount of play extending in the longitudinal direction of the axial hole of 0.1 [mm] or less with respect to the shaft diameter of the rotating shaft.
4. A printer according to any one of claims 1 to 3. The head support plate has at least one of an opening penetrating through the head support surface and a notch formed by cutting an outer periphery of the head support surface.
5. A printer according to any one of claims 1 to 4.

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