WO2025164275A1 - Printer - Google Patents

Abstract

Provided is a printer in which a clutch spring can be easily fitted to a drive gear.　The printer comprises a drive gear 66, a clutch spring 68, and a drive cam 67. The drive gear 66 includes a gear 66A and a shaft 65. The shaft 65 includes a first shaft portion 66B, a tapered portion 66C, and a second shaft portion 66D. The clutch spring 68 is fitted onto the first shaft portion 66B. The tapered portion 66C extends upward from an upper end of the first shaft portion 66B, and has an outer diameter that becomes smaller in the upward direction. The second shaft portion 66D extends upward from an upper end of the tapered portion 66C. A second diameter R2 of the second shaft portion 66D is smaller than a first diameter R1 of the first shaft portion 66B. The clutch spring 68 has an inner diameter R4 that is smaller than the first diameter R1 and larger than the second diameter R2 when not fitted onto the first shaft portion 66B. The drive cam 67 is fitted onto the shaft 65 and includes a spring accommodating portion 67B. The spring accommodating portion 67B opens downward and accommodates the clutch spring 68.

Description

printer

The present invention relates to a printer.

The printer in Patent Document 1 has a cassette loading section. A cassette containing an ink ribbon and other materials is loaded into the cassette loading section. The cassette has a ribbon take-up roller that winds up the ink ribbon used in printing. The printer's cassette loading section is provided with a ribbon drive gear for rotating the ribbon take-up roller. A clutch spring is attached to the shaft of the ribbon drive gear to apply a constant rotational torque.

Japanese Patent Application Laid-Open No. 2022-72729

When attaching the clutch spring to the ribbon drive gear during the manufacturing process of the printer, the diameter of the clutch spring had to be expanded by hand. This made the process of attaching the clutch spring to the ribbon drive gear cumbersome for workers.

The object of the present invention is to provide a printer that allows for easy attachment of a clutch spring to a drive gear.

The printer according to the present invention comprises: a mounting section into which a cassette having an ink ribbon used for printing and a take-up spool for taking up the ink ribbon can be mounted; a drive gear including a gear that rotates by the driving force of a drive source and a shaft that rotates together with the gear and extends upward from the gear and is exposed in the mounting section; an annular clutch spring mounted on the shaft; and a drive cam that is mounted on the shaft and is capable of engaging with the take-up spool on its outer surface, and is rotated by torque imparted by the clutch spring as the shaft rotates, thereby rotating the take-up spool, and the shaft is The clutch spring is provided with a first shaft portion extending upward from the gear and on which the clutch spring is attached; a tapered portion extending upward from the upper end of the first shaft portion and having an outer diameter that decreases as it extends upward; and a second shaft portion extending upward from the upper end of the tapered portion, wherein the second diameter, which is the maximum outer diameter of the second shaft portion, is smaller than the first diameter, which is the maximum outer diameter of the first shaft portion; the clutch spring has an inner diameter smaller than the first diameter and larger than the second diameter when not attached to the first shaft portion; and the drive cam is provided with a spring accommodating portion that opens downward and accommodates the clutch spring.

In the above printer, when the clutch spring is not attached to the first shaft portion, the inner diameter of the clutch spring is smaller than the first diameter of the first shaft portion and larger than the second diameter. During manufacturing, the worker first inserts the clutch spring into the second shaft portion. In this case, the clutch spring is inserted, for example, up to the area around the tapered portion. The worker then attaches the drive cam to the drive gear shaft from above. In this case, the spring accommodating portion of the drive gear abuts against the clutch spring and moves downward. The clutch spring moves toward the first shaft portion via the tapered portion, expanding its inner diameter as it moves toward the first shaft portion. Once the drive cam has been attached to the drive gear, the clutch spring is attached to the first shaft portion. Therefore, the printer makes it easy to attach the clutch spring to the drive gear.

In the present invention, during the process of attaching the drive cam to the shaft, the spring accommodating portion may abut against the clutch spring from above and move it downward, thereby attaching the clutch spring to the first shaft portion. Therefore, the printer can easily attach the clutch spring to the drive gear.

In the present invention, a hook is provided on the second shaft portion, and the hook has an extension portion that extends in the vertical direction and a protrusion portion that protrudes radially outward from the upper end of the extension portion of the shaft, and the protrusion portion is located above the upper end of the drive cam when the drive cam is attached to the shaft, and may protrude radially outward beyond the inner wall of the drive cam. In the printer, the vertical position of the drive cam relative to the drive gear is fixed.

In the present invention, the extension portion may be flexible and bend radially inward when the drive cam is attached to the shaft. When the drive cam is attached to the shaft, the hook bends radially inward. Therefore, the hook does not interfere with the attachment of the drive cam to the shaft.

In the present invention, the protrusion may have a tapered surface that slopes outward in the radial direction as it extends downward. When attached to the drive cam shaft, the tapered surface can smoothly guide the drive cam downward.

In the present invention, the shaft may be cylindrical and inserted into a shaft provided in the mounting portion, the drive cam may be inserted into the shaft, and the amount by which the protrusion protrudes radially outward beyond the inner wall of the drive cam may be greater than the radial length of the gap between the shaft and the inner wall of the hook. In the printer, even if the hook bends radially inward while the drive cam is mounted on the shaft, the hook continues to engage with the drive cam. Therefore, the printer can more reliably prevent the drive cam from coming off the shaft.

In the present invention, the clutch spring may comprise a main body portion extending spirally in the vertical direction, a first arm portion extending from the upper end of the main body portion radially outward from the shaft, and a second arm portion extending from the lower end of the main body portion radially outward, and the clutch spring may have a shape symmetrical in the vertical direction. Because the clutch spring has a shape symmetrical in the vertical direction, an operator can insert the clutch spring onto the shaft without making a mistake in the orientation.

In the present invention, the spring accommodating portion comprises a disk-shaped upper wall that covers the clutch spring from above, and a peripheral wall that extends downward from the radially outer end of the upper wall and covers the clutch spring from the radially outer side, the peripheral wall having a notch formed in the lower end of the peripheral wall and extending upward from the circumferential center of the peripheral wall, the notch having a first portion having a first circumferential length and a second portion that extends upward from the circumferential center of the first portion and has a second circumferential length shorter than the first length, the first arm abutting against the second portion and being positioned in the circumferential direction, and the second arm may be disposed on the first portion. The position of the second arm of the clutch spring relative to the first arm varies due to dimensional errors. Because the length of the first portion is longer than the second portion, the second arm of the clutch spring fits within the first portion. Furthermore, the second arm of the clutch spring does not abut against the first portion even when there is variation due to dimensional errors. Therefore, the torque of the clutch spring is appropriately applied to the drive cam.

In the present invention, the second portion may be provided with a first wall extending radially inward from an end portion on one side in the circumferential direction, and a second wall extending radially inward from an end portion on the other side in the circumferential direction, the first wall abutting against the first arm portion from one side in the circumferential direction, and the second wall abutting against the first arm portion from the other side in the circumferential direction. The second portion can abut against the first arm portion more reliably via the first wall and the second wall.

In the present invention, the radially outer end of the first arm may be positioned radially inward from the second portion, and the radially outer end of the second arm may be positioned radially inward from the first portion. In the printer, the clutch spring is housed inside the spring accommodating portion. This reduces the possibility that an operator or printer user will come into contact with the clutch spring during work.

In the present invention, the drive gear further includes a third shaft portion extending upward from the second shaft portion and having a third diameter smaller than the inner diameter of the clutch spring when the clutch spring is not attached to the first shaft portion, and the third shaft portion may be provided with a transmission gear that transmits the driving force to the cassette. When it is necessary to transmit driving force to the cassette, the drive gear requires greater torque. Therefore, the diameter of the clutch spring must be smaller. Even in such a case, the worker can easily attach the clutch spring to the drive gear. Furthermore, since the third shaft portion is located above the second shaft portion, the shaft becomes longer in the upward direction. Even in this case, since the third diameter of the third shaft portion is smaller than the inner diameter of the clutch spring, the clutch spring can be moved smoothly to the first shaft portion.

In the present invention, the drive gear and the drive cam may be made of different materials. If the drive gear and the drive cam were made of the same material, resonance would likely occur during friction, causing the sliding load to become unstable. This would result in unstable torque when winding the ink ribbon. Therefore, by combining a drive gear and drive cam made of different materials, the printer can achieve stable torque when winding the ink ribbon.

FIG. 1 is a perspective view of a printer 1. FIG. 2 is a perspective view of the printer 1 with the rear cover 3 removed. FIG. 2 is a perspective view of a printing unit 50. FIG. 2 is a perspective view of a platen unit 80. FIG. FIG. 10 is an exploded perspective view of the drive shaft 63. 8 is a cross-sectional view of the spring accommodating portion 67B taken along the line BB. FIG. 10 is a cross-sectional view of the spring accommodating portion 67B taken along the line CC. 2 is a cross-sectional view of the drive shaft 63 taken along the line AA. FIG. 2 is a perspective view of the tape cassette 100. FIG. 2 is an exploded perspective view of the tape cassette 100. FIG. 10 is a plan view showing a state in which the heat sink 72 and the print head 71 are positioned by a jig 140. FIG. 2 is a plan view showing a state in which the print head 71 is positioned relative to the platen roller 82. FIG. 14 is a simplified enlarged plan view of an area C in FIG. 13. 10A to 10C are diagrams showing the assembly procedure of the drive shaft 63. 10 is a table showing the specifications of each gear 131, 134, 137, 138, and 139.

A printer 1 and tape cassette 100 according to one embodiment of the present invention will be described with reference to the drawings. The drawings are used to explain the technical features that may be adopted by the present invention. In other words, the configurations and the like shown in the drawings are not intended to be limiting, but are merely illustrative examples. In describing this embodiment, the upper left, lower right, right, left, upper right, and lower left sides of Figure 1 will be referred to as the lower, upper, right, left, front, and rear sides of the printer 1, respectively.

The configuration of printer 1 will now be described. As shown in Figures 1 and 2, printer 1 is a portable label printer. Printer 1 can print images onto tape 101 (see Figure 10) pulled out from tape cassette 100 to create labels. Printer 1 can print images such as text and graphics onto tape 101.

As shown in Figures 1 and 2, the printer 1 comprises a housing 2, a rear cover 3, a display unit 4, and an input unit 5. The housing 2 is box-shaped and long in the front-to-rear direction, with an opening at the rear. An inner lid 6 is attached to the opening, protecting the inside of the housing 2. The top wall 2A of the housing 2 is formed with an ejection passage 29 that penetrates in the front-to-rear direction, and a fastening hole 2C that engages with the opening/closing portion 31 of the rear cover 3.

The rear cover 3 is removably attached to the housing 2. The rear cover 3 extends in the front-to-rear direction and has a concave shape that is recessed upward. When attached, the rear cover 3 covers the entire rear surface of the housing 2 and closes the rear opening together with the inner lid 6.

The rear cover 3 has a window 35 at the front right position, through which the inside of the housing 2 can be seen from the outside. The position of the window 35 corresponds to the right side of the inside of the cassette loading section 10. When a tape cassette 100 is loaded into the cassette loading section 10, the user can see the label affixed to the top surface of the tape cassette 100 through the window 35. The label indicates the type of tape 101, etc.

The display unit 4 is, for example, a liquid crystal display, and is capable of displaying various types of information. The display unit 4 is located in front of the center in the front-to-rear direction on the underside 2B of the housing 2. The input unit 5 accepts various types of information input by user operation. The input unit 5 is located on the underside 2B of the housing 2, behind the display unit 4. The input unit 5 includes multiple keys, such as character keys, a print button, and an Esc key.

As shown in FIG. 2, the printer 1 includes a cassette loading section 10, a battery storage section 40, and a printing section 50 inside the housing 2. The cassette loading section 10 removably loads a tape cassette 100. The cassette loading section 10 is formed in the inner cover 6 on the rear of the housing 2, at a position forward of the center in the front-to-back direction. The cassette loading section 10 is recessed downward. The cassette loading section 10 has a recess bottom surface 11 and recess peripheral surfaces 12-15. The recess peripheral surfaces 12-15 connect to the edges of the recess bottom surface 11 and surround the periphery in the front-to-back and left-to-right directions.

The battery housing section 40 houses a battery (not shown). The battery housing section 40 is formed in the inner lid 6 on the back of the housing 2, in a recessed shape that is recessed downward, at a position rearward of the center of the housing 2 in the front-to-rear direction. When the rear cover 3 is removed from the housing 2, the cassette loading section 10 and battery housing section 40 are exposed to the outside of the printer 1 through an opening on the back of the housing 2. With the rear cover 3 removed from the housing 2, the user can replace the tape cassette 100 and the battery, respectively.

The printing unit 50 is a unit configured to print on the tape 101. The printing unit 50 is located at the front of the housing 2, below the left end of the cassette loading unit 10. As shown in Figure 3, the printing unit 50 includes a base 51, a head unit 70, a platen unit 80, a drive mechanism 60, etc.

As shown in Figure 3, the base 51 is a metal plate that supports the components of the printing unit 50. The base 51 faces the plate surface in the up-down direction and extends longer in the front-to-back direction than in the left-to-right direction. The base 51 is provided with an attachment portion 141, pin 51A (see Figure 12), pin 51B, shaft 52, etc. The attachment portion 141 is provided at the front end and center in the left-to-right direction of the base 51. The attachment portion 141 extends upward. The plate surface of the attachment portion 141 faces the front-to-back direction. The attachment portion 141 is a metal plate that supports a cutting blade (not shown). In cooperation with the attachment portion 141, the cutting blade cuts the printed tape 101 (see Figure 10). Pins 51A and 51B are provided at the front end and center in the left-to-right direction of the base 51. Pin 51A is located in front of pin 51B (see Figure 12). Pins 51A and 51B are cylindrical and extend upward from the base 51. Shaft 52 is located on the right side of the front end of the base 51 and extends upward.

As shown in Figure 3, the head unit 70 is assembled to the base 51. The head unit 70 comprises a heat sink 72 and a print head 71. The heat sink 72 is a metal plate that holds the print head 71 and dissipates heat. The heat sink 72 is located at the front end of the base 51, in the center in the left-right direction. The heat sink 72 comprises a lower end 72F and a right end 72U. The lower end 72F faces the plate surface in the up-down direction and extends longer in the front-to-back direction than in the left-to-right direction. The lower end 72F has two holes 72A (see Figure 12) and 72B. Hole 72A is located in front of hole 72B. Holes 72A and 72B extend in the front-to-back direction. Pins 51A and 51B are inserted into holes 72A and 72B, respectively. In this state, the lower end 72F is fixed to the base 51 with screws 51C.

The right end 72U extends upward from the right end of the lower end 72F. The right end 72U faces the plate surface in the left-right direction and extends longer in the front-to-back direction than in the up-to-down direction. The front upper end of the right end 72U protrudes higher than the lower upper end. The upper surface of the front upper end of the right end 72U functions as the support part 18 when the tape cassette 100 is installed.

The print head 71 is fixed with adhesive to the left surface of the right end 72U of the heat sink 72. The print head 71 is a rectangular circuit board on which multiple heating elements 71A and a driver circuit unit 71B are mounted. The multiple heating elements 71A are arranged vertically at the front end of the left surface of the board. The driver circuit unit 71B is formed at the rear end of the left surface of the board and is electrically connected to a control unit (not shown) inside the housing 2 via a harness 73.

As shown in Figures 3 and 4, the platen unit 80 is positioned on the left side of the base 51. The rear end of the platen unit 80 is supported on the rotation shaft 53 so that the front end can swing left and right. In Figure 4, the configuration of the parts before assembly is shown by a two-dot chain line. The rotation shaft 53 of the platen unit 80 is located on the left side of the rear end of the base 51 and extends upward. By swinging the platen unit 80, the platen roller 82 can swing between a close position (see Figure 13) where it approaches the print head 71, and a distant position (see Figures 3 and 12) where it is away from the print head 71. For convenience, the orientation of each part of the platen unit 80 in the following description is based on the orientation of each part of the printer 1 when the platen roller 82 is in the close position.

The platen unit 80 comprises a platen holder 81, a platen shaft 84, a platen roller 82, a platen gear 83, and a detection unit 91. The platen holder 81 is long in the front-to-rear direction and is box-shaped with an opening on the right side. The platen holder 81 has support holes 81A that penetrate vertically in the lower and upper walls at the rear end. The support holes 81A are supported by the rotation shaft 53 of the base 51. The lower and upper walls of the platen holder 81 have bulging portions 81B, 81B that bulge to the right at the front end. The bulging portions 81B, 81B have through-holes (not shown) that penetrate vertically. The platen roller 82 is rotatably supported between the bulging portions 81B, 81B.

The platen shaft 84 is an axial member that extends in the vertical direction. The platen shaft 84 has insertion holes 84A and 84B at its upper end and center in the vertical direction. Engagement pins 85 and 86 are inserted into the insertion holes 84A and 84B. The engagement pins 85 and 86 are rod members that are longer than the diameter of the platen shaft 84. When inserted into the insertion holes 84A and 84B, the engagement pins 85 and 86 each penetrate the platen shaft 84 in the radial direction. In addition, a groove 84C that engages with a retaining ring 87 is formed at the lower end of the platen shaft 84.

The platen roller 82 has a roller body 82A and a roller sleeve 82B. The roller sleeve 82B is a cylindrical member through which the platen shaft 84 is inserted. The roller sleeve 82B rotates on its axis together with the platen shaft 84. Furthermore, a notch 82E that penetrates radially through the cylindrical wall surface is formed at the upper end of the roller sleeve 82B, matching the position of the groove 82D. The roller body 82A is a cylindrical member that is fitted onto the outer peripheral surface of the middle part of the roller sleeve 82B. The roller body 82A rotates on its axis together with the platen shaft 84 and roller sleeve 82B.

The platen gear 83 is fixed to the upper end of a platen shaft 84 that protrudes upward from a bulge 81B on the upper wall side. The platen gear 83 is a so-called helical gear, with gear teeth twisted at a predetermined angle relative to the rotation axis L4 (see Figure 11). An engagement pin 85 at the upper end of the platen shaft 84 engages with a groove 83B formed on the inner surface of a through hole 83A provided at the rotation center of the platen gear 83. The engagement pin 85 transmits torque from the platen gear 83 to the platen shaft 84. Therefore, the platen shaft 84 rotates together with the platen gear 83.

When the platen roller 82 is in the proximity position (see Figure 13), the roller body 82A sandwiches the tape 101 and ink ribbon 104 between it and the print head 71. The platen gear 83 meshes with the output gear 131 of the tape cassette 100 (see Figures 10 and 11). The driving force of the drive shaft 63, which will be described later, is input to the platen roller 82 via the tape cassette 100 and the platen gear 83. As the platen roller 82 rotates, the roller body 82A transports the tape 101 sandwiched between it and the print head 71 toward the discharge path 29.

As shown in Figure 3, the platen holder 81 has a holding portion 81C located closer to the rear end than the middle portion in the front-to-rear direction. The holding portion 81C is concave and recessed to the left. The holding portion 81C holds a detection portion 91. The detection portion 91 is composed of a mechanical switch. The detection portion 91 is switched on and off by the detected portion 125 of the tape cassette 100 (see Figures 10 and 11). The detection portion 92 detects the cassette identification information provided to the tape cassette 100 based on the combination of on and off switches.

As shown in Figure 3, the drive mechanism 60 includes a motor 61, a gear group 62, and a drive shaft 63, and is mounted on the base 51. The motor 61 is the drive source and is located at the rear end of the base 51. The driving force of the motor 61 is transmitted to the drive shaft 63, which is located on the right side of the front end of the base 51, by a gear group 62, which connects multiple gears. The motor 61, gear group 62, and base 51 are located below the inner lid 6 inside the housing 2.

The drive shaft 63 will be described with reference to Figures 5 to 9. The drive shaft 63 is inserted into the shaft 52 (see Figure 3) provided on the base 51. The drive shaft 63 is exposed inside the cassette mounting section 10 from an opening formed in the bottom surface 11 of the recess (see Figure 2). When the tape cassette 100 is mounted in the cassette mounting section 10, the drive shaft 63 is inserted into the take-up spool 107 (see Figure 11) and input gear 134 (see Figure 11) of the tape cassette 100 (see Figure 9). Driving force transmitted from the motor 61 (see Figure 3) is input to the drive shaft 63 via the gear group 62. The drive shaft 63 rotates the take-up spool 107 and input gear 134 by the driving force from the motor 61.

The drive shaft 63 includes a drive gear 66, a clutch spring 68, and a drive cam 67. The driving force of the motor 61 is transmitted to the drive gear 66 via the gear group 62. The drive gear 66 is made of, for example, a resin material. The drive gear 66 includes a gear 66A and a shaft 65. The gear 66A meshes with the most downstream gear of the gear group 62 (see Figure 3). The gear 66A rotates via the gear group 62 (see Figure 3) by the driving force of the motor 61 (see Figure 3). The shaft 65 extends upward from the gear 66A. The shaft 65 is cylindrical. The shaft 65 has a smaller diameter than the gear 66A. The shaft 65 is inserted into the shaft 52 (see Figure 3). The shaft 65 rotates around the shaft 52 (see Figure 3) together with the gear 66A.

The shaft 65 comprises a first shaft portion 66B, a tapered portion 66C, a second shaft portion 66D, and a third shaft portion 66E. The first shaft portion 66B extends upward from the center of the gear 66A. The first shaft portion 66B is cylindrical. The outer diameter of the first shaft portion 66B is constant in the vertical direction. The outer diameter of the first shaft portion 66B is referred to as the first diameter R1. The tapered portion 66C extends upward from the first shaft portion 66B, and the outer diameter becomes smaller as it extends upward.

The second shaft portion 66D extends upward from the upper end of the tapered portion 66C. The second shaft portion 66D is cylindrical. The outer diameter of the second shaft portion 66D is constant in the vertical direction. The outer diameter of the second shaft portion 66D is referred to as the second diameter R2. The second diameter R2 of the second shaft portion 66D is smaller than the first diameter R1 of the first shaft portion 66B.

A hook 75 is provided on the second shaft portion 66D. The hook 75 is arranged around the periphery of the second shaft portion 66D. The hook 75 positions the drive cam 67 and prevents it from coming loose.

The hook 75 has an extension 75A and a protrusion 75B. The extension 75A extends upward from the lower end of the second shaft portion 66D. The extension 75A is flexible in the radial direction of the shaft 65. The protrusion 75B protrudes radially outward from the upper end of the extension 75A. The protrusion 75B has a tapered surface 759. The tapered surface 759 slopes radially outward as it extends downward. When the drive cam 67 (described below) is attached to the shaft 65, the protrusion 75B is located above the upper end of the drive cam 67 and protrudes radially outward beyond the inner wall of the drive cam 67. The lower surface of the protrusion 75B contacts the upper end of the drive cam 67 from above.

Here, length L15 shown in Figure 9 is the radial length of the gap between the shaft 52 and the inner wall of the hook 75. Protrusion amount L17 is the amount by which the protrusion 75B protrudes radially outward beyond the inner wall of the drive cam 67. Protrusion amount L17 is greater than length L15. As a result, even if the hook 75 bends toward the shaft 52, for example, the hook 75 continues to abut against the drive cam 67 from above. This prevents the drive cam 67 from coming loose.

The third shaft portion 66E extends upward from the upper end of the second shaft portion 66D. The third shaft portion 66E extends upward from the second shaft portion 66D. The third shaft portion 66E is cylindrical. The third shaft portion 66E has a constant outer diameter in the vertical direction. The outer diameter of the third shaft portion 66E is referred to as the third diameter R3. The third diameter R3 is smaller than the second diameter R2. A transmission gear 679 extending in the vertical direction is provided on the third shaft portion 66E. The third shaft portion 66E is inserted into the input gear 134 (see Figure 11), which will be described later. The third shaft portion 66E transmits the driving force from the motor 61 to the input gear 134 via the transmission gear 679.

The clutch spring 68 is a coil spring. The clutch spring 68 has a main body 68A, a first arm 68B, and a second arm 68C. The main body 68A is attached to the outer peripheral surface of the first shaft 66B of the drive gear 66. The main body 68A extends spirally in the vertical direction. When not attached to the drive gear 66, the main body 68A has an inner diameter R4 that is smaller than the first diameter R1 and larger than the second diameter R2. The third diameter R3 of the third shaft 66E is smaller than the inner diameter R4 of the clutch spring 68 when the clutch spring 68 is not attached to the first shaft 66B.

The first arm 68B extends radially outward from the upper end of the main body 68A. The second arm 68C extends radially outward from the lower end of the main body 68A. Before being attached to the first shaft 66B, the second arm 68C is spaced radially apart from the first arm 68B (see Figure 6). When the main body 68A is attached to the first shaft 66B, the inner diameter R4 of the main body 68A before attachment expands to the first diameter R1. As a result, the second arm 68C is closer radially to the first arm 68B than it was before being attached to the first shaft 66B (see Figure 5).

The drive cam 67 is attached to the shaft 65. The drive cam 67 is a cylindrical part. The drive cam 67 is made of, for example, a resin material different from that of the drive gear 66. In this case, the drive cam 67 is made of a resin material of a different type or grade than that of the drive gear 66. The drive cam 67 is inserted into the take-up spool 107 (see Figure 11) of the tape cassette 100, which will be described later. The drive cam 67 transmits the driving force from the motor 61 (see Figure 3) to the take-up spool 107.

The drive cam 67 has a cam portion 67A and a spring accommodating portion 67B. The cam portion 67A is inserted into the take-up spool 107. The cam portion 67A is cylindrical and extends in the vertical direction. The cam portion 67A has an inner diameter R5. The inner diameter R5 of the cam portion 67A is larger than the second diameter R2 of the second shaft portion 66D. The cam portion 67A is disposed around the second shaft portion 66D. The cam portion 67A transmits the driving force transmitted from the drive gear 66 to the take-up spool 107 (see Figure 11).

The spring accommodating portion 67B is provided at the lower end of the cam portion 67A. The spring accommodating portion 67B is arranged around the first shaft portion 66B. The spring accommodating portion 67B includes an upper wall 675 and a peripheral wall 676. The upper wall 675 extends radially outward from the lower end of the cam portion 67A. In other words, the upper wall 675 is disc-shaped, with a central portion that is perforated in the vertical direction. The upper wall 675 covers the clutch spring 68 from above (see Figure 5). The peripheral wall 676 extends downward from the radially outer end of the upper wall 675. The upper wall 675 covers the clutch spring 68 from the radially outer side (see Figure 5).

A notch 67C is formed in the peripheral wall 676, extending upward from the lower end. The notch 67C comprises a first portion 671 and a second portion 672. The first portion 671 has a circumferential length of a first length L11 (see Figure 6). The second portion 672 extends upward from the circumferential center of the first portion 671. The second portion 672 has a circumferential length of a second length L13 (see Figure 6). The second length L13 is shorter than the first length L11.

The second portion 672 is provided with a first wall 672A and a second wall 672B. The first wall 672A and the second wall 672B face each other in the circumferential direction. The first wall 672A has an extension portion 673 and an abutment portion 674 (see Figure 7). The extension portion 673 extends from its radially outer end toward the inside toward the second wall 672B. The abutment portion 674 extends radially from the radially inner end of the extension portion 673. In other words, the first wall 672A extends radially inward from one circumferential end.

The second wall 672B has an extension portion 677 and an abutment portion 678. The extension portion 677 extends from the radially outer end toward the first wall 672A as it moves inward. The abutment portion 678 extends radially from the radially inner end of the extension portion 677. In other words, the second wall 672B extends radially inward from the other circumferential end.

As shown in FIG. 7, the abutment portion 674 of the first wall 672A abuts against the first arm portion 68B from one circumferential side. The abutment portion 678 of the second wall 672B abuts against the first arm portion 68B from the other circumferential side. Therefore, the first arm portion 68B of the clutch spring 68 abuts against the second portion 672 and is positioned circumferentially. In addition, the radially outer end of the first arm portion 68B of the clutch spring 68 is positioned more inward than the radially outer end of the second portion 672.

As shown in FIG. 8, the second arm 68C of the clutch spring 68 is positioned inside the first portion 671. Therefore, the second arm 68C does not contact the first portion 671. Furthermore, the radially outer end of the second arm 68C is positioned more inward than the radially outer end of the first portion 671.

The configuration of the tape cassette 100 will be described with reference to Figures 10 and 11. The tape cassette 100 stores the tape 101. By replacing the tape cassette 100, it is possible to replenish the tape 101 and change the type of tape 101 (e.g., size, color, material, etc.).

The tape cassette 100 includes a main case 120. The main case 120 houses the tape 101 and the ink ribbon 104. The main case 120 has a first case 121 and a second case 122. The first case 121 and the second case 122 are each rectangular parallelepiped. In other words, the external shape of the main case 120 when viewed from above and below is rectangular. The main case 120 is inserted into the cassette mounting portion 10 with the first case 121 facing the bottom surface 11 of the recess of the cassette mounting portion 10 (see Figure 2).

The tape cassette 100 comprises a tape roll 102, a tape spool 103, a ribbon roll 105, a ribbon spool 106, a take-up spool 107, and a drive transmission mechanism 130. The tape roll 102 is formed by winding a strip of tape 101, on which printing is performed, around an axis on the tape spool 103. The axis of the tape roll 102 is parallel to the vertical direction.

Two spacer films 111, 112 are arranged on the outer side of the tape roll 102 in the vertical direction, sandwiching the tape roll 102. The spacer film 111 is arranged between the tape roll 102 and the second cover portion 180, and the spacer film 112 is arranged between the tape roll 102 and the second frame portion 170. The tape 101 pulled out from the tape roll 102 is guided by the first roller 113 and the second roller 114.

The tape spool 103 is rotatable around a rotation axis that is parallel to the vertical direction. The tape spool 103 rotates as the tape 101 is transported by the platen roller 82 of the printer 1. As a result, the tape spool 103 supplies the tape 101 to the head opening 123 (see Figure 10). The rotation axis of the tape spool 103 coincides with the axis of the tape roll 102. A clutch spring (not shown) held by the clutch spring holder 115 applies rotational resistance to the tape spool 103.

The ribbon roll 105 is a strip-shaped ink ribbon 104 used for printing on the tape 101, wound around a ribbon spool 106 around its axis. The ink ribbon 104 is overlapped with the tape 101 at the head opening 123 and used for printing by the print head 71. After printing, the ink ribbon 104 is taken up onto a take-up spool 107. The ribbon roll 105 is positioned in a different vertical position (specifically, below) than the tape roll 102. The ribbon roll 105 is also positioned in the same vertical position as the head opening 123.

The ribbon spool 106 is rotatable around its axis of rotation, which is parallel to the vertical direction. The ribbon spool 106 rotates as the ink ribbon 104 is taken up by the take-up spool 107, thereby supplying the ink ribbon 104 to the print head 71. A clutch spring (not shown) held by the clutch spring holder 116 applies rotational resistance to the ribbon spool 106.

The take-up spool 107 is rotatable around its axis of rotation. The axis of rotation of the take-up spool 107 is parallel to the axis of rotation of the ribbon spool 106. The take-up spool 107 is cylindrical and has a hollow portion defined by an inner peripheral surface 108. Spline teeth 109 are provided on the inner peripheral surface 108 of the take-up spool 107. The cam portion 67A of the drive cam 67 of the drive shaft 63 is connected to the spline teeth 109. The take-up spool 107 is rotated by the cam portion 67A and winds up the ink ribbon 104. A torsion spring 110 provides rotational resistance to the take-up spool 107. The torsion spring 110 is disposed between the take-up spool 107 and the first frame portion 160.

The drive transmission mechanism 130 transmits the drive force transmitted via the transmission gear 679 of the third shaft portion 66E of the drive shaft 63 to the platen roller 82. The drive transmission mechanism 130 has an input gear 134, an idle gear 137, and an output gear 131.

The input gear 134 indirectly engages with the output gear 131 via the idle gear 137, transmitting the driving force to the output gear 131. The input gear 134 has a gear portion 135 and a spool portion 136. The spool portion 136 is a cylindrical internal gear with spline teeth on its inner circumferential surface. The gear portion 135 is an external gear that meshes with the upstream gear 138 of the idle gear 137. The spool portion 136 is fixed to the underside of the gear portion 135, and the third shaft portion 66E of the drive shaft 63 is inserted from below. The gear portion 135 rotates integrally with the spool portion 136 due to the driving force input to the spool portion 136 from the third shaft portion 66E. The rotational axis L2 of the input gear 134 is aligned on the same line as the rotational axis of the take-up spool 107 and is parallel to the rotational axis L1 of the output gear 131.

The rotation axis L2 of the input gear 134 overlaps with the hollow portion of the take-up spool 107 in the vertical direction. Therefore, when the tape cassette 100 is attached to the cassette attachment portion 10, the drive shaft 63 is inserted through the take-up spool 107 and the input gear 134 at the same time. As a result, the input gear 134 is rotated by the drive shaft 63 together with the take-up spool 107.

The idle gear 137 meshes with the input gear 134 and the output gear 131, and transmits the driving force input to the input gear 134 to the output gear 131. The idle gear 137 is a stepped gear in which an upstream gear 138 and a downstream gear 139 are arranged side by side on the same axis. The upstream gear 138 is an externally toothed spur gear that meshes with the input gear 134. The downstream gear 139 is an externally toothed helical gear that meshes with the output gear 131. The gear teeth of the downstream gear 139 are twisted in the opposite direction to the output gear 131. The diameter of the downstream gear 139 is smaller than the diameter of the upstream gear 138. Furthermore, the downstream gear 139 is arranged closer to the tape roll 102 in the vertical direction than the upstream gear 138.

The rotational axis L3 of the idle gear 137 is parallel to the rotational axis L1 of the output gear 131 and the rotational axis L2 of the input gear 134. The idle gear 137 reduces the rotational speed of the driving force input to the input gear 134 and transmits it to the output gear 131. In other words, the drive transmission mechanism 130 includes a reduction mechanism.

The output gear 131 is an externally toothed gear. By meshing with the platen gear 83, the output gear 131 transmits the driving force for transporting the tape 101 to the platen gear 83. The output gear 131 is a helical gear whose gear teeth are twisted at a predetermined angle relative to the rotation axis L1. The rotation axis L1 of the output gear 131 is parallel to the rotation axis L2 of the input gear 134 and the rotation axis L4 of the platen gear 83.

A portion of the output gear 131 is exposed in the space communicating with the head opening 123. When the tape cassette 100 is attached to the cassette attachment section 10, the output gear 131 meshes with the platen gear 83 in the space communicating with the head opening 123.

The specifications of the output gear 131, the gear portion 135 of the input gear 134, the upstream gear 138 and the downstream gear 139 of the idle gear 137 (step gear) are as shown in FIG.
The individual elements of the specifications of the output gear 131, input gear 134, and idle gear 137 (step gear) listed in the table shown in Figure 16 may be changed as appropriate, as long as the combination is compatible with the drive transmission mechanism 130 as a whole.

The printing operation of the printer 1 will now be described. When printing, the tape cassette 100 is loaded into the cassette loading section 10. In this case, the print head 71 is positioned in the head opening 123 so that it overlaps vertically with the tape 101 and ink ribbon 104. The drive cam 67 of the drive shaft 63 is inserted into the take-up spool 107. Furthermore, the third shaft portion 66E of the drive shaft 63 is inserted into the input gear 134. The platen roller 82 moves to the adjacent position. This causes the platen gear 83 to mesh with the output gear 131.

With the tape cassette 100 installed, the input gear 134 is rotated by the third shaft portion 66E of the drive shaft 63. This rotates the output gear 131 via the idle gear 137. Furthermore, the rotation of the output gear 131 rotates the platen gear 83, which in turn rotates the platen roller 82. The tape 101 is transported to the head opening 123 by the platen roller 82.

Meanwhile, as the gear 66A of the drive gear 66 rotates, the shaft 65 rotates. In this case, the clutch spring 68 reduces the diameter of the main body 68A due to friction with the first shaft portion 66B. This increases the torque of the clutch spring 68. The clutch spring 68 transmits the driving force from the drive gear 66 to the drive cam 67 via the first arm portion 68B and the second portion 672. The drive cam 67 is imparted with the torque of the clutch spring 68. The drive cam 67 rotates due to the transmitted driving force. As the drive cam 67 rotates, the cam portion 67A rotates the take-up spool 107. This unwinds the ink ribbon 104 from the ribbon roll 105. The ink ribbon 104 is transported toward the head opening 123.

At the head opening 123, the tape 101 is pressed against the print head 71 via the ink ribbon 104 by the platen roller 82. The print head 71 selectively heats the heating elements 71A. This causes some of the ink on the surface of the ink ribbon 104 to be transferred to the tape 101, printing characters, symbols, etc. on the tape 101. The platen roller 82 transports the printed tape 101 from the tape cassette 100 toward the discharge path 29. The used ink ribbon 104 is taken up onto the take-up spool 107.

With reference to Figures 12 to 14, the positioning of the print head 71 and platen roller 82 during the manufacturing process of the printer 1 will be described. As shown in Figure 12, the worker uses a jig 140 to position the print head 71. The jig 140 is a rectangular parallelepiped that extends in the left-right direction. The worker abuts the jig 140 against the left end of the mounting portion 141 from behind.

The worker places the heat sink 72 on the base 51. The pins 51A and 51B of the base 51 are inserted into the holes 72A and 72B at the lower end 72F of the heat sink 72, respectively. Because the holes 72A and 72B are long in the front-to-rear direction, the heat sink 72 can move in the front-to-rear direction relative to the base 51.

The worker brings the front end of the right end 72U of the heat sink 72 into contact with the rear surface of the jig 140 from behind. This positions the heat sink 72 in the front-to-rear direction. In this state, the worker secures the heat sink 72 to the base 51 with screws 51C. As a result, the print head 71 is positioned relative to the platen roller 82, which is in the proximity position.

As shown in Figures 13 and 14, the worker can also position the heat sink 72, and therefore the print head 71, based on the position of the platen roller 82. The worker moves the platen roller 82 to the proximity position. When the platen roller 82 is in the proximity position, the notch 82E faces to the right. The worker uses the position of the notch 82E as a guide to position the heating elements 71A of the print head 71. In this case, the front-to-rear center C1 of the platen roller 82 is positioned a distance L5 forward of the front-to-rear center C2 of the heating elements 71A. In this state, the worker secures the heat sink 72 to the base 51 with screws 51C. Therefore, the print head 71 is positioned relative to the platen roller 82 in the proximity position.

With reference to Figure 15, the assembly procedure for the drive shaft 63 during the assembly work of the printing unit 50 will be described. During manufacturing, the worker inserts the clutch spring 68 into the second shaft portion 66D (see Figure 15 (A)). In this case, the clutch spring 68 is inserted, for example, up to the area around the tapered portion 66C.

Then, the worker attaches the drive cam 67 to the shaft 65 of the drive gear 66 from above (see Figures 15(A) and (B)). The drive cam 67 is guided downward by the tapered surface 759 of the hook 75. Furthermore, the extension 75A of the hook 75 bends radially inward when the drive cam 67 is attached to the shaft 65. Therefore, the drive cam 67 moves smoothly downward relative to the shaft 65.

The worker brings the spring accommodating portion 67B of the drive cam 67 into contact with the clutch spring 68 (see Figure 15 (B)). In this case, the upper wall 675 of the spring accommodating portion 67B comes into contact with the main body portion 68A of the clutch spring 68 from above. The worker places the first arm portion 68B of the clutch spring 68 against the second portion 672 of the spring accommodating portion 67B. The worker can easily perform the work because he or she can see the clutch spring 68 through the cutout 67C.

The operator further moves the drive cam 67 downward relative to the shaft 65 (see Figures 15 (B) and (C)). In this case, the spring accommodating portion 67B of the drive gear 66 abuts the clutch spring 68 and moves downward. The clutch spring 68 moves toward the first shaft portion 66B via the tapered portion 66C, expanding its inner diameter R4 as it moves toward the first shaft portion 66B. In this case, the second arm portion 68C of the clutch spring 68 moves toward the first arm portion 68B. When the clutch spring 68 is attached to the drive gear 66, the clutch spring 68 is attached to the first shaft portion 66B.

The drive gear 66 is prevented from coming off the shaft 65 by a hook 75 (see Figure 15 (C)). The first arm 68B of the clutch spring 68 is positioned in the second part 672 of the spring accommodating portion 67B. The second arm 68C of the clutch spring 68 is positioned in the first part 671 of the spring accommodating portion 67B.

As described above, the shaft 65 includes a first shaft portion 66B, a tapered portion 66C, and a second shaft portion 66D. The first shaft portion 66B extends upward from the gear 66A and has a clutch spring 68 attached thereto. The tapered portion 66C extends upward from the upper end of the first shaft portion 66B, and its outer diameter decreases as it extends upward. The second shaft portion 66D extends upward from the upper end of the tapered portion 66C. The second diameter R2, which is the maximum outer diameter of the second shaft portion 66D, is smaller than the first diameter R1, which is the maximum outer diameter of the first shaft portion 66B. When not attached to the first shaft portion 66B, the clutch spring 68 has an inner diameter R4 that is smaller than the first diameter R1 and larger than the second diameter R2. The drive cam 67 is provided with a spring housing 67B. The spring housing 67B opens downward and houses the clutch spring 68.

In the printer 1 described above, the inner diameter R4 of the clutch spring 68 is smaller than the first diameter R1 of the first shaft portion 66B and larger than the second diameter R2. During manufacturing, an operator inserts the clutch spring 68 onto the second shaft portion 66D. In this case, the clutch spring 68 is inserted, for example, up to the area around the tapered portion 66C. The operator then attaches the drive cam 67 to the shaft 65 of the drive gear 66 from above. In this case, the spring accommodating portion 67B of the drive gear 66 abuts against the clutch spring 68 and moves downward. The clutch spring 68 moves toward the first shaft portion 66B via the tapered portion 66C while expanding its inner diameter R4. When the clutch spring 68 is attached to the drive gear 66, the clutch spring 68 is attached to the first shaft portion 66B. Therefore, the printer 1 makes it easy to attach the clutch spring 68 to the drive gear 66.

When the drive cam 67 is attached to the shaft 65, the spring accommodating portion 67B contacts the clutch spring 68 from above and moves it downward, attaching the clutch spring 68 to the first shaft portion 66B. Therefore, the printer 1 can easily attach the clutch spring 68 to the drive gear 66.

A hook 75 is provided on the second shaft portion 66D. The hook 75 has an extension portion 75A and a protrusion portion 75B. The extension portion 75A extends in the vertical direction. The protrusion portion 75B protrudes radially outward from the upper end of the extension portion 75A of the shaft 65. When the drive cam 67 is attached to the shaft 65, the protrusion portion 75B is positioned above the upper end of the drive cam 67 and protrudes radially outward from the inner wall of the drive cam 67. In the printer 1, the vertical position of the drive cam 67 relative to the drive gear 66 is fixed.

The extension portion 75A is flexible and bends radially inward when the drive cam 67 is attached to the shaft 65. When the drive cam 67 is attached to the shaft 65, the hook 75 bends radially inward. Therefore, the hook 75 does not interfere with the attachment of the drive cam 67 to the shaft 65.

The protrusion 75B has a tapered surface 759 that slopes radially outward as it extends downward. When the drive cam 67 is attached to the shaft 65, the tapered surface 759 can smoothly guide the drive cam 67 downward.

The shaft 65 is cylindrical and is inserted into the shaft 52 provided in the cassette mounting section 10. The drive cam 67 is inserted into the shaft 65. The radial length L15 of the gap between the shaft 52 and the inner wall of the hook 75 is greater than the radial length L17 of the protrusion 75B that protrudes radially outward from the inner wall of the drive cam 67. In the printer 1, even if the hook 75 bends radially inward when the drive cam 67 is attached to the shaft 65, the hook 75 continues to engage with the drive cam 67. Therefore, the printer 1 can more reliably prevent the drive cam 67 from coming off the shaft 65.

The clutch spring 68 comprises a main body 68A, a first arm 68B, and a second arm 68C. The main body 68A extends spirally in the vertical direction. The first arm 68B extends from the upper end of the main body 68A radially outward from the shaft 65. The second arm 68C extends from the lower end of the main body 68A radially outward. The clutch spring 68 has a shape that is symmetrical in the vertical direction. Because the shape of the clutch spring 68 is symmetrical in the vertical direction, the operator can insert the clutch spring 68 onto the shaft 65 without making a mistake in the orientation of the clutch spring 68.

The spring accommodating portion 67B comprises an upper wall 675 and a peripheral wall 676. The upper wall 675 is disc-shaped and covers the clutch spring 68 from above. The peripheral wall 676 extends downward from the radially outer end of the upper wall 675 and covers the clutch spring 68 from the radially outer side. A notch 67C is formed in the peripheral wall 676 and faces upward from the lower end of the peripheral wall 676. The notch 67C comprises a first portion 671 and a second portion 672. The first portion 671 has a circumferential length of a first length L11. The second portion 672 extends upward from the circumferential center of the first portion 671 and has a circumferential length of a second length L13 that is shorter than the first length L11. The first arm portion 68B abuts against the second portion 672 and is positioned circumferentially. The second arm portion 68C is disposed in the first portion 671. The position of the second arm 68C of the clutch spring 68 relative to the first arm 68B varies due to dimensional errors. Because the first length L11 of the first portion 671 is longer than the second length L13 of the second portion 672, the second arm 68C of the clutch spring 68 fits within the first portion 671. Furthermore, even if there is variation due to dimensional errors, the second arm 68C of the clutch spring 68 does not come into contact with the first portion 671. Therefore, the torque of the clutch spring 68 is appropriately applied to the drive cam 67.

The second portion 672 is provided with a first wall 672A and a second wall 672B. The first wall 672A extends radially inward from an end on one circumferential side. The second wall 672B extends radially inward from an end on the other circumferential side. The first wall 672A abuts against the first arm portion 68B from one circumferential side. The second wall 672B abuts against the first arm portion 68B from the other circumferential side. The first wall 672A and the second wall 672B allow the second portion 672 to abut against the first arm portion 68B more reliably.

The radially outer end of the first arm 68B is positioned radially inward from the second portion 672. The radially outer end of the second arm 68C is positioned radially inward from the first portion 671. In the printer 1, the clutch spring 68 fits inside the spring accommodating portion 67B. This reduces the possibility that an operator or a user of the printer 1 will come into contact with the clutch spring 68.

The drive gear 66 has a third shaft portion 66E. The third shaft portion 66E has a third diameter R3. The third diameter R3 is smaller than the inner diameter R4 of the clutch spring 68 when the clutch spring 68 is not attached to the first shaft portion 66B. The third shaft portion 66E extends upward from the second shaft portion 66D. A transmission gear 679 is provided on the third shaft portion 66E. The transmission gear 679 transmits driving force to the tape cassette 100. When it is necessary to transmit driving force to the tape cassette 100, the drive gear 66 requires greater torque. Therefore, the diameter of the clutch spring 68 needs to be smaller. Even in such cases, the operator can easily attach the clutch spring 68 to the drive gear 66. Furthermore, since the third shaft portion 66E is located above the second shaft portion 66D, the shaft 65 becomes longer in the upward direction. Even in this case, the third diameter R3 of the third shaft portion 66E is smaller than the inner diameter R4 of the clutch spring 68, so the clutch spring 68 can be moved smoothly to the first shaft portion 66B.

The drive gear 66 and the drive cam 67 are made of different materials. If the drive cam 67 and the drive gear 66 were made of the same material, resonance would easily occur during friction, and the sliding load would be unstable. This would cause the torque when winding the ink ribbon 104 to become unstable. By combining a drive gear 66 and drive cam 67 made of different materials, it is possible to stabilize the torque when winding the ink ribbon 104.

In the above embodiment, the cassette mounting unit 10 is an example of a "mounting unit" in the present invention. The tape cassette 100 is an example of a "cassette" in the present invention. The motor 61 is an example of a "drive source" in the present invention.

The present invention can be modified from the above embodiment. In the above embodiment, the drive shaft 63 was applied to the take-up spool 107 of the ink ribbon 104, but this is not limited to this. The drive shaft 63 may also be applied to the rotational drive of something other than the take-up spool 107 of the ink ribbon 104.

In the above embodiment, the shaft 65 was cylindrical, but this is not limited to this. For example, the internal shape of the shaft 65 may be a shape other than cylindrical. For example, it may be polygonal. The length of the shaft 65 may also be changed as appropriate. The shapes and lengths of the first shaft portion 66B, second shaft portion 66D, and third shaft portion 66E may be changed as appropriate. The shapes of the shaft 52, take-up spool 107, input gear 134, etc. may be changed accordingly.

In the above embodiment, the outer diameter of the first shaft portion 66B is constant across the vertical direction, but this is not limited to this. For example, the first diameter R1 of the first shaft portion 66B does not have to be constant. The same applies to the second diameter R2 of the second shaft portion 66D and the third diameter R3 of the third shaft portion 66E. It is sufficient that the relationship in size between the first diameter R1, second diameter R2, third diameter R3, and inner diameter R4 is maintained.

In the above embodiment, the drive cam 67 was cylindrical, but this is not limited to this. The shape of the drive cam 67 may be changed as appropriate.

In the above embodiment, the hook 75 has a tapered surface 759 on the protruding portion 75B, but this is not limited to this. The tapered surface 759 does not have to be provided as long as it does not interfere with the attachment of the drive cam 67 to the shaft 65.

In the above embodiment, the clutch spring 68 has a vertically symmetrical shape, but this is not limited to this. As long as the clutch spring 68 can be properly attached to the first shaft portion 66B and can apply torque to the drive cam 67, the shape and dimensions of the clutch spring 68 may be changed as appropriate.

In the above embodiment, the notch 67C allows the clutch spring 68 to be visible, but this is not limited to this. For example, the clutch spring 68 does not have to be visible. For example, a groove corresponding to the notch 67C may be formed on the inside of the peripheral wall 676, and the first arm 68B and second arm 68C may be positioned in that portion.

In the above embodiment, the drive gear 66 is provided with a third shaft portion 66E, but this is not limited to this. For example, the drive gear 66 does not have to be provided with a third shaft portion 66E. In this case, the transmission of driving force to the platen gear 83 can be achieved by a separate mechanism.

In the above embodiment, the tape cassette 100 is a receptor type that transfers ink from the ink ribbon 104 onto the surface of the tape 101, but this is not limited to this. The cassette may also be capable of printing on various types of tape, such as double-sided adhesive tape, film tape, and laminated tape.

In the above embodiment, the drive gear 66 and the drive cam 67 were made of resin, but this is not limited to this. For example, the drive gear 66 and the drive cam 67 may be made of a material other than resin, such as metal. As long as torque stabilization during winding of the ink ribbon 104 can be achieved, the materials of the drive gear 66 and the drive cam 67 may be combined in any way.

1 Printer 10 Cassette mounting section 52 Shaft 62 Gear group 65 Shaft 66B First shaft portion 66C Tapered portion 66D Second shaft portion 66E Third shaft portion 67 Drive cam 67B Spring accommodating portion 68 Clutch spring 68A Main body portion 68B First arm portion 68C Second arm portion 75 Hook 75A Extension portion 75B Protrusion 100 Tape cassette 675 Upper wall 676 Peripheral wall 671 First portion 672 Second portion 672A First wall 672B Second wall 759 Tapered surfaces R1, R2, R3, R4 Diameters L15, L17 Length

Claims (12)

a mounting portion into which a cassette having an ink ribbon used for printing and a take-up spool for taking up the ink ribbon can be mounted;
a drive gear including a gear that rotates by a driving force of a driving source and a shaft that rotates together with the gear and extends upward from the gear to be exposed at the mounting portion;
an annular clutch spring attached to the shaft;
a drive cam, which is a cylindrical cam attached to the shaft and can engage with the take-up spool on its outer surface, and which rotates when torque is applied from the clutch spring due to rotation of the shaft, thereby rotating the take-up spool;
The axis is
a first shaft portion extending upward from the gear and having the clutch spring attached thereto; a tapered portion extending upward from an upper end of the first shaft portion and having an outer diameter that decreases as it extends upward;
a second shaft portion extending upward from an upper end of the tapered portion,
a second diameter that is the maximum outer diameter of the second shaft portion is smaller than a first diameter that is the maximum outer diameter of the first shaft portion,
the clutch spring has an inner diameter smaller than the first diameter and larger than the second diameter when not attached to the first shaft portion,
The printer is characterized in that the drive cam is provided with a spring accommodating portion that opens downward and accommodates the clutch spring. The printer according to claim 1, characterized in that, during the process of attaching the drive cam to the shaft, the spring accommodating portion abuts the clutch spring from above and moves it downward, thereby attaching the clutch spring to the first shaft portion. The second shaft portion is provided with a hook,
The hook is
an extension portion extending in the vertical direction;
a protruding portion protruding radially outward from an upper end of the extension portion,
The protrusion is
2. The printer according to claim 1, wherein, when the drive cam is attached to the shaft, the shaft is positioned above the upper end of the drive cam and protrudes radially outward beyond the inner wall of the drive cam. 4. The printer according to claim 3, wherein the extension portion is flexible and bends radially inward when the drive cam is attached to the shaft. 5. The printer according to claim 4, wherein the protrusion has a tapered surface that slopes outward in the radial direction as it extends downward. The shaft is cylindrical and is inserted into a shaft provided in the mounting portion,
The drive cam is inserted onto the shaft,
The printer according to claim 4, wherein the amount by which the protrusion protrudes radially outward beyond the inner wall of the drive cam is greater than the radial length of the gap between the shaft and the inner wall of the hook. The clutch spring is
a main body portion extending spirally in the vertical direction;
a first arm portion extending from an upper end of the main body portion toward an outer side in a radial direction of the shaft;
a second arm portion extending radially outward from a lower end of the main body portion,
2. The printer according to claim 1, wherein the clutch spring has a shape symmetrical in the vertical direction. The spring accommodating portion is
a disk-shaped upper wall that covers the clutch spring from above;
a peripheral wall extending downward from an outer end of the upper wall in the radial direction and covering the clutch spring from the outer side in the radial direction,
The peripheral wall has a notch formed in it that extends from a lower end of the peripheral wall to the upper end,
The cutout is
a first portion having a first circumferential length;
a second portion extending upward from a center of the first portion in the circumferential direction and having a second length in the circumferential direction that is shorter than the first length;
the first arm portion abuts against the second portion and is positioned in the circumferential direction;
The printer of claim 7 , wherein the second arm is disposed on the first portion. The second portion comprises:
a first wall extending from an end portion on one side in the circumferential direction toward the inside in the radial direction, and a second wall extending from an end portion on the other side in the circumferential direction toward the inside in the radial direction,
the first wall abuts against the first arm portion from one side in the circumferential direction,
The printer according to claim 8 , wherein the second wall abuts against the first arm portion from the other side in the circumferential direction. an outer end of the first arm portion in the radial direction is disposed more inward than the second portion in the radial direction;
The printer according to claim 9 , wherein the radially outer end of the second arm portion is positioned radially inward of the first portion. the drive gear further includes a third shaft portion extending upward from the second shaft portion and having a third diameter smaller than the inner diameter of the clutch spring when the clutch spring is not attached to the first shaft portion,
2. The printer according to claim 1, wherein the third shaft portion is provided with a transmission gear for transmitting the driving force to the cassette. 2. The printer according to claim 1, wherein the drive gear and the drive cam are made of different materials.