JP7472883B2 - Printing device - Google Patents

Description

The present invention relates to a printing device.

As a printing device that produces labels by printing ink from an ink ribbon onto a tape material, for example, a thermal transfer printing device disclosed in Patent Document 1 is known.

JP 2020-151918 A

In the ribbon feed mechanism of the tape printing device disclosed in Patent Document 1, the rotation of the feed motor is transmitted to a one-way clutch, and depending on the direction of rotation of the feed motor, the transmission of rotation to the payout rotor, which pays out the ink ribbon, and the take-up rotor, which takes up the ink ribbon, is permitted or restricted. However, this ribbon feed mechanism makes it difficult to apply tension to the ink ribbon, and there is a problem that the ink ribbon becomes slack when the take-up rotor is rotated by the feed motor, for example.

The present invention was developed to address these problems, and aims to provide a printing device that is less likely to cause sagging in the ink ribbon.

In order to achieve the above object, a printing device of the present invention includes a platen roller that is capable of transporting a print medium and an ink ribbon in a forward transport direction and a reverse transport direction by rotating while pressing the print medium and the ink ribbon so that the print medium and the ink ribbon are interposed between the platen roller and a thermal head, a take-up core around which the ink ribbon pulled out from a roll body wound around a supply core is wound and rewound when the ink ribbon is transported in the forward transport direction by the platen roller, a drive source that outputs rotational power, a first drive mechanism that transmits the rotational power output by the drive source to the platen roller as the rotational power of the platen roller , and a rotation shaft having a predetermined engagement portion that is inserted through and engaged with the take-up core of the supply core and the take-up core, and a rotation shaft that causes the ink ribbon to be wound around the take-up core, and and a second drive mechanism that transmits the rotational power output by the drive source as a rolling force , wherein the second drive mechanism is provided with a one-way gear in a path that transmits the rotational power output by the drive source to the rotating shaft, the one-way gear transmitting the rotational power in a direction corresponding to the forward transport direction among the rotational power output by the drive source while blocking the rotational power in a direction corresponding to the reverse transport direction, so that when the ink ribbon is transported in the reverse transport direction, the ink ribbon is pulled out from the take-up core only by the rotational power transmitted to the platen roller among the rotational power output by the drive source, and the rotational speed of the rotating shaft generated in association with the pulling out of the ink ribbon from the take-up core is slower than the rotational speed of the rotating shaft when the rotational power in the direction corresponding to the forward transport direction is transmitted from the drive source via the second drive mechanism.

The present invention provides a printing device that is less likely to cause sagging in the ink ribbon.

1 is a perspective view of a printing apparatus according to an embodiment of the present invention. 2 is a perspective view showing a main part of the internal structure housed in a housing of the printing device shown in FIG. 1 and a tape cartridge that is detachably attachable to this main part; FIG. 2A is a plan view showing the main parts of the internal structure housed in the housing of the printing device shown in FIG. 1 and the tape cartridge attached to this main part, and FIG. 2B is an enlarged view focusing on the part in FIG. 2A where the tape material and ink ribbon are clamped between the platen roller and the thermal head. FIG. 4 is a perspective view focusing on a drive mechanism for the platen roller and the ribbon take-up shaft shown in FIG. FIG. 5 is a cross-sectional view of the one-way gear shown in FIG. 4 . FIG. 5 is a cross-sectional view focusing on the ribbon winding shaft shown in FIG. 4 . 5A and 5B are explanatory diagrams for explaining the operation of the drive mechanism during forward transport, where FIG. 5A shows the operation of the entire drive mechanism, and FIG. 5B shows the operation of the one-way gear. 5A and 5B are diagrams illustrating the operation of the drive mechanism when starting reverse conveyance, where FIG. 5A illustrates the operation of the entire drive mechanism, and FIG. 5B illustrates the operation of the one-way gear. 5A and 5B are explanatory diagrams for explaining the operation of the drive mechanism during reverse conveyance, where FIG. 5A shows the operation of the entire drive mechanism, and FIG. 5B shows the operation of the one-way gear.

Below, a printing device according to an embodiment of the present invention will be described with reference to the drawings. In describing the printing device, as shown in FIG. 1, an orthogonal coordinate system will be referred to where appropriate, in which an X-axis and a Y-axis extending horizontally and a Z-axis perpendicular to the X-axis and Y-axis are defined. In this orthogonal coordinate system, the +X-axis direction is the direction in which the print medium is discharged, and the +Z-axis direction is the upper side of the printing device. The printing device 1 shown in FIG. 1 is a label printer, and prints on a tape material M (FIG. 2), which is the print medium, transported by a transport unit. The printing device 1 prints based on print data received from an information processing device such as a personal computer or tablet terminal (not shown).

As shown in FIG. 1, the housing 2 of the printing device 1 has a cylindrical shape with an oval-shaped bottom surface. The surface of the housing 2 that corresponds to the side surface of the cylinder has two flat surfaces 2a that are perpendicular to the bottom surface, and two curved surfaces 2b that connect the two flat surfaces 2a. Furthermore, a recess 2c is formed in one of the two curved surfaces 2b on the +X-axis direction side.

An outlet 2d is formed in the recess 2c. The tape material M (FIG. 2) that has been printed in the printing device 1 is discharged from the device through the outlet 2d. The outlet 2d is a slit-shaped opening that extends in a direction parallel to the Y-axis direction.

As shown in FIG. 2, the inside of the housing 2 contains a main part 8 of an internal structure made up of various parts. This main part 8 has a base part 11 having a flat plate part 11a to which various parts are attached, and a cartridge holding part 12 provided on the base part 11.

The cartridge holding section 12 has a holding section main body 12a capable of holding the tape cartridge 30, and a number of legs 12b erected on the flat plate section 11a and spaced apart in the Y-axis direction between the flat plate section 11a and the holding section main body 12a. There are, for example, four legs 12b, and two of them are shown in FIG. 2. The holding section main body 12a is formed with a cartridge storage section 12c that defines a space for storing the tape cartridge 30. In addition, the holding section main body 12a is formed with a protruding tape core engagement shaft 22.

The tape cartridge 30 is removably accommodated in the cartridge accommodating section 12c. FIG. 3(a) shows the tape cartridge 30 accommodated in the cartridge accommodating section 12c.

As shown in FIG. 3(a), the tape cartridge 30 is formed with a thermal head insertion portion 36, which is a recess into which the thermal head 10 is inserted. The tape cartridge 30 also has a cartridge case 31 that houses the tape material M and the ink ribbon R. The cartridge case 31 is provided with a tape core 32, a ribbon supply core 34, and a ribbon take-up core 35.

The tape member M is wound in a roll on a tape core 32 inside the cartridge case 31. The tape member M is, for example, a tape having a base material with an adhesive layer and a release paper removably attached to the base material so as to cover the adhesive layer. The ink ribbon R for thermal transfer is wound in a roll on a ribbon supply core 34 inside the cartridge case 31 with its tip wound around a ribbon take-up core 35. The tape member M and the ink ribbon R are arranged so as to overlap and straddle the concave thermal head insertion portion 36.

As shown in Figs. 2 and 3(a), the main section 8 includes a thermal head 10 having a plurality of heating elements for printing on the tape material M, a platen roller 21 as a transport section for transporting the tape material M and the ink ribbon R, and a ribbon winding shaft 23 for winding up the used ink ribbon R. The thermal head 10 and the platen roller 21 are provided in a position to sandwich the tape material M and the ink ribbon R across the thermal head insertion section 36. The ribbon winding shaft 23 is provided in a state in which it penetrates the holding section main body 12a and protrudes into the cartridge storage section 12c. As described later, in this embodiment, the tape material M and the ink ribbon R are transported while being sandwiched at least between the thermal head 10 and the platen roller 21, so the term "transport section" will be used even when both the thermal head 10 and the platen roller 21 are included.

As shown in FIG. 3(a), the main section 8 further includes a full cutter 17 and a half cutter 16 near the discharge port 2d (FIG. 1). The full cutter 17 is a cutter that cuts the tape material M to create tape pieces. On the other hand, the half cutter 16 is a cutter that makes cuts in the tip portion of the tape material M, etc.

When the tape cartridge 30 is stored in the cartridge storage section 12c, as shown in FIG. 3(a), the thermal head 10 is inserted into the thermal head insertion section 36 formed in the cartridge case 31. Also, as shown in FIG. 2, the tape core 32 of the tape cartridge 30 engages with the tape core engagement shaft 22, and further, the ribbon take-up core 35 engages with the ribbon take-up shaft 23. Note that the tape core engagement shaft 22 does not have to be provided, and the tape cartridge 30 may be positioned by the ribbon take-up core 35, the thermal head insertion section 36, etc.

The platen roller 21 has a cylindrical shape as shown in FIG. 4, and rotates (also called pivots) around the axis 21a. As shown in FIG. 3(b), the platen roller 21 rotates in the direction of the arrow R1 while pressing the tape material M and the ink ribbon R against the thermal head 10, thereby forward transporting the tape material M and the ink ribbon R. This forward transport is called forward transport, and at this time the tape material M is transported in the direction of the arrow Y1 (first direction). On the other hand, as shown in FIG. 3(b), the platen roller 21 rotates in the direction of the arrow R2, and the tape material M and the ink ribbon R are transported in the reverse direction. This reverse transport is called reverse transport, and at this time the tape material M is transported in the direction of the arrow Y2 (second direction). This direction of the arrow Y2 (second direction) is opposite to the direction of the arrow Y1 (first direction).

As shown in FIG. 4, the ribbon take-up shaft 23 can rotate around the shaft portion 25 in the direction of the arrow R3 or the direction of the arrow R4. As described later, the ribbon take-up shaft 23 rotates in the direction of the arrow R3 as shown in FIG. 3(a) during forward transport. As a result, the ink ribbon R transported forward in the direction of the arrow Y1 by the platen roller 21 is transported in the direction of the arrow Y5 and wound up on the ribbon take-up core 35. On the other hand, the ribbon take-up shaft 23 cannot operate the ribbon take-up core 35 during reverse transport as described later. The ink ribbon R transported backward in the direction of the arrow Y6 by the platen roller 21 is pulled out from the ribbon take-up core 35, causing the ribbon take-up shaft 23 to rotate in the direction of the arrow R4.

The platen roller 21 and the ribbon take-up shaft 23 are driven by the power transmitted from the motor 24 as a drive source attached to the base portion 11 shown in FIG. 4. The motor 24 is, for example, a stepping motor, and has a rotor, a stator, an encoder, etc. The rotational motion of the motor 24 is output from the output gear G1 attached to the output shaft. Each gear shown in FIG. 4 is provided on the surface of the flat plate portion 11a facing the cartridge holding portion 12 (FIG. 2). Note that in FIG. 4, FIG. 7, FIG. 8, and FIG. 9, the tooth shapes of each gear are omitted as appropriate to make the figures easier to understand. The rotational motion output from the output gear G1 is transmitted to gear G2, gear G3, gear G4, gear G5, gear G6, gear G7, and gear G8, and the platen roller 21 connected to gear G8 rotates. In this way, the output gear G1, gear G2, gear G3, gear G4, gear G5, gear G6, gear G7, and gear G8 that transmit power from the motor 24 to the platen roller 21 are referred to as a first drive mechanism. The rotational motion output from the output gear G1 is transmitted to gear G2, gear G3, gear G9, gear G10, gear G11, and gear G12, and the ribbon winding shaft 23 connected to the gear G12 via a torque limiter rotates. In this way, the output gear G1, gear G2, gear G3, gear G9, gear G10, gear G11, and gear G12 that transmit power from the motor 24 to the ribbon winding shaft 23 are referred to as a second drive mechanism. Here, among the multiple gears of the second drive mechanism, gear G10 is a one-way gear that serves as a transmission part that transmits rotation in only one direction.

As shown in FIG. 5, the gear G10 has a first gear portion 42 having a gear body portion 42b that meshes with the gear G9 and a protruding portion 42a that protrudes from the gear body portion 42b in the direction in which the rotation shaft 41 extends (Y-axis direction), a one-way clutch 45 in which the protruding portion 42a of the first gear portion 42 and the inner ring 43 are engaged, and a second gear portion 46 that is engaged with the outer ring 44 of the one-way clutch 45. This second gear portion 46 meshes with the gear G11. During forward conveyance, the rotational force of the first gear portion 42 that meshes with the gear G9 is transmitted to the second gear portion 46 via the one-way clutch 45. On the other hand, during reverse conveyance, the rotational force of the first gear portion 42 that meshes with the gear G9 is transmitted to the inner ring 43 of the one-way clutch 45, but is not transmitted to the outer ring 44 and the second gear portion 46. The one-way clutch 45 is, for example, a cam type, but other types of one-way clutches may be used.

As shown in FIG. 6, the ribbon winding shaft 23 has a shaft portion 25 having an engagement portion 26 on its outer periphery that engages with the ribbon winding core 35 (FIG. 2), and a spring 28 provided between the shaft portion 25 and the torque limiter 27. The ribbon winding shaft 23 engaged with the ribbon winding core 35 of the tape cartridge 30 shown in FIG. 2 rotates together with the ribbon winding core 35. The ribbon winding shaft 23 is connected to a gear G12 meshed with a gear G11 via a torque limiter 27. The gear G12 has a protruding portion 29 that protrudes in the direction of the rotation axis (extending in the Y-axis direction). The torque limiter 27 is provided at the tip of the protruding portion 29.

The torque limiter 27 is a felt type, and has a rotating part 27a that rotates with the gear G12, and two felts 27b that are arranged to sandwich the rotating part 27a. A flange part 25a provided on the shaft part 25 is housed between the rotating part 27a and the protruding part 29 of the gear G12. When a difference occurs between the rotational motion of the gear G12 and the rotational motion of the ribbon winding shaft 23, and a torque equal to or greater than a threshold value acts on the torque limiter 27, the felt 27b slips on the shaft part 25, preventing the generation of excessive torque. The slip here refers to a state in which the felt 27b slips or spins freely on the shaft part 25. The torque limiter 27 is not limited to the felt type, and can be selected from among known torque limiters, such as those with a friction plate interposed.

When print data is input from an information processing device (not shown) to the printing device 1, the motor 24 rotates forward as shown in FIG. 7(a), forwardly transporting the tape material M and the ink ribbon R. At this time, the output gear G1 rotates clockwise (in the same direction as R2 and R3 in this embodiment), and this rotational motion is transmitted to each gear. At this time, in the gear G10, which is a one-way gear, the clockwise rotational motion in the figure of the first gear portion 42 is transmitted to the second gear portion 46 via the one-way clutch 45 as shown in FIG. 7(b). Note that in FIG. 7(b), FIG. 8(b), and FIG. 9(b), hatching is used to make the one-way clutch 45 easier to recognize, but this hatching does not represent a cross section.

During forward transport, the gear G8 to which the platen roller 21 is connected rotates counterclockwise (the same direction as R1 and R4 in this embodiment) as shown in FIG. 7(a). Accordingly, the platen roller 21 rotates in the direction of arrow R1 (counterclockwise) around the axis 21a while pressing the overlapping tape material M and ink ribbon R against the thermal head 10 (FIG. 3(a)). As a result, the tape material M is unwound from the tape core 32 shown in FIG. 3(a), and the ink ribbon R is unwound from the ribbon supply core 34 shown in FIG. 3(a). The tape material M and ink ribbon R thus transported forward pass between the thermal head 10 and the platen roller 21 in an overlapping state in the direction shown by arrow Y1 as shown in FIG. 3(b). At that time, the ink ribbon R is heated by the thermal head 10, and the ink is thermally transferred to the tape material M. The printed tape material M is then transported in the direction of arrow Y3, cut by the full cutter 17 (Figure 3(a)), and discharged from the device through the discharge port 2d (Figure 1).

Meanwhile, the gear G12 to which the ribbon winding shaft 23 is connected rotates clockwise as shown in FIG. 7(a). Accordingly, the ribbon winding shaft 23 rotates clockwise (in the direction of arrow R3) around the shaft portion 25. As a result, the ink ribbon R is transported in the direction of arrow Y5 and wound by the ribbon winding core 35.

The rotation speed of the gear G12, which rotates by the forward rotation (clockwise in this embodiment) of the motor 24, is faster than the transport speed of the ink ribbon R transported by the platen roller 21 (the rotation speed of the platen roller 21). For example, the rotation speed of the gear G12 is set to 1.1 to 2.0 times the rotation speed of the platen roller 21 that transports the ink ribbon R, and is set to 1.129 times in this embodiment. This is to eliminate the phenomenon that the ink ribbon R becomes slack if the ink ribbon R is not tensioned properly immediately after it is sandwiched between the thermal head 10 and the platen roller 21. This rotation speed is determined taking into consideration various factors such as the gear ratio of the first drive mechanism and the second drive mechanism, the diameter of the platen roller 21, or the diameter of the ribbon winding core 35.

In this way, the rotation speed of the gear G12 is set faster than the rotation speed of the platen roller 21. However, the ink ribbon R sandwiched between the thermal head 10 and the platen roller 21 cannot be pulled out faster than the conveying speed of the platen roller 21. Therefore, as shown in FIG. 6, the torque acting between the fast rotating gear G12 and the slowly rotating shaft portion 25 is suppressed by slipping the felt 27b of the torque limiter 27. In this way, by winding the ink ribbon R by the ribbon winding shaft 23 while slipping the felt 27b, an appropriate tension can be continuously applied to the ink ribbon R, and slack can be prevented from occurring in the ink ribbon R during forward conveyance.

The printing device 1 (FIG. 1) performs a series of operations, including printing the tape member M, cutting it with the full cutter 17 (FIG. 3(a)), and discharging it from the discharge port 2d (FIG. 1), and then performs an operation to shorten the margin at the leading edge of the printed material. As shown in FIG. 3(a), when the tape member M is cut by the full cutter 17 and the next printing is performed as it is, a margin MA corresponding to the distance between the full cutter 17 and the thermal head 10 is formed at the leading edge of the printed material. In order to shorten this margin MA, the motor 24 shown in FIG. 8(a) is reversed before the next printing is performed, and the tape member M and the ink ribbon R are conveyed in reverse. By reversing the motor 24, the output gear G1 rotates counterclockwise, and this rotational motion is transmitted to each gear. At this time, as shown in FIG. 8(b), the first gear portion 42 of the gear G10, which is a one-way gear, rotates counterclockwise in the figure, but this rotational motion is not transmitted to the second gear portion 46 by the one-way clutch 45. Therefore, the reverse rotation motion of the motor 24 (FIG. 4) is not transmitted to the gear G11 meshed with the second gear portion 46 and the gear G12 meshed with the gear G11. On the other hand, the gear G8 to which the platen roller 21 is connected rotates in the clockwise direction indicated by the arrow R2 as shown in FIG. 8(a).

As gear G8 rotates, the platen roller 21 rotates clockwise around shaft 21a as indicated by arrow R2 while pressing the tape material M and ink ribbon R against the thermal head 10 (Figure 3(b)). As a result, the tape material M and ink ribbon R are reverse-transported in the direction indicated by arrow Y2 in Figure 9(a) while being clamped between the platen roller 21 and the thermal head 10. As a result, the portion of the tape material M already sent out by the platen roller 21 is pulled back in the direction of arrow Y4. Meanwhile, the wound portion of the ink ribbon R is pulled out from the ribbon take-up core 35 (ribbon take-up shaft 23) as indicated by arrow Y6. In this way, the tape material M and ink ribbon R are reverse-transported by the platen roller 21 at a constant speed (equal speed). If the gear G10 were not a one-way gear but a normal gear capable of clockwise and counterclockwise rotation, and the gear G12 were configured to rotate counterclockwise by the motor 24 at a rotation speed between 1.1 and 2.0 times the conveying speed of the ink ribbon R during forward conveyance, the ink ribbon R would not be tensioned and would sag downstream of the thermal head 10 and the platen roller 21. In this embodiment, the tape material M and the ink ribbon R are conveyed at a constant speed while being sandwiched between the platen roller 21 and the thermal head 10 (i.e., the ink ribbon R is pulled out from the ribbon take-up shaft 23 by the power from the motor 24 transmitted to the first drive mechanism), so that problems such as the ink ribbon R sagging during reverse conveyance can be prevented, and wrinkles and conveyance jams caused by conveying the ink ribbon R in a slack state can be prevented.

As the ink ribbon R is pulled out from the ribbon take-up core 35, the gear G12 connected to the ribbon take-up shaft 23 rotates counterclockwise as shown by the dashed arrow in FIG. 9(a). This rotational motion of the gear G12 is transmitted to the gear G11 and the second gear portion 46 of the gear G10, to which the reverse motion of the motor 24 is not transmitted. As a result, the gear G11 and the second gear portion 46 rotate in the direction shown by the dashed arrow.

At this time, in the gear G10, which is a one-way gear, the first gear portion 42 to which the reverse rotation motion of the motor 24 is transmitted rotates counterclockwise in the figure as shown by the solid arrow, as shown in FIG. 9B. On the other hand, the second gear portion 46 to which the rotation motion of the gear G12 is transmitted rotates counterclockwise in the figure as shown by the dashed arrow. As described above, the second drive mechanism that transmits the rotation motion to the ribbon take-up shaft 23 transmits a motion that results in a faster transport speed than the first drive mechanism that transmits the rotation motion to the platen roller 21. Therefore, the rotation of the second gear portion 46 that rotates due to the transport of the ink ribbon R by the platen roller 21 is slower than the rotation of the first gear portion 42 that rotates by the transmission of motion from the motor 24. In other words, the first gear portion 42 is in a relationship in which it rotates counterclockwise with respect to the second gear portion 46, and this relationship is the same as the relationship between the first gear portion 42 and the second gear portion 46 described with reference to FIG. 8B. Therefore, the rotational motion of the first gear portion 42 and the rotational motion of the second gear portion 46 are not affected in any way by the one-way clutch 45 interposed between them.

According to the above embodiment, a one-way gear that transmits only the motion during forward transport is incorporated into the gear G10 of the second drive mechanism that transmits power from the motor 24 to the ribbon take-up shaft 23. As a result, during reverse transport, the ink ribbon R is transported in reverse while being clamped between the thermal head 10 and the platen roller 21 together with the tape member M. In this way, the ink ribbon R is transported in reverse at the same speed as the tape member M, so the ink ribbon R does not sag.

During reverse transport, the ink ribbon R is pulled out from the ribbon take-up core 35 and rotates the ribbon take-up shaft 23. As a result, a tension sufficient to rotate the ribbon take-up shaft 23 acts on the ink ribbon R during reverse transport. This makes it possible to maintain a state in which tension acts on the ink ribbon R during reverse transport, and to prevent sagging or wrinkles from occurring in the ink ribbon R.

The ribbon take-up shaft 23 and gear G12 are also connected via a torque limiter 27, and the rotational speed of the gear G12 is set faster than the rotational speed of the platen roller 21 required to transport the ink ribbon R. This allows the torque limiter 27 to be applied during forward transport while maintaining an appropriate tension on the ink ribbon R. This makes it possible to prevent sagging or wrinkles from occurring in the ink ribbon R during forward transport.

In this way, appropriate tension can be applied to the ink ribbon R during forward and reverse transport, which can prevent sagging or wrinkles from occurring in the ink ribbon R. This makes it possible to shorten the margin formed at the leading edge of the printed material by reverse transporting the tape member and ink ribbon before printing is performed.

This invention is not limited to the above embodiment, and various modifications and applications are possible. In the above embodiment, a printing device 1 is described that is assumed to be connected to a computer, tablet, smartphone, etc. via a wired or wireless connection, but the printing device may also be equipped with a keyboard and display and the user may directly input the print contents into the printing device.

In addition, although the second gear portion 46 and the outer ring 44 have been described as separate parts, it is also possible to adopt a second gear portion incorporating a part corresponding to the outer ring 44. Similarly, although the first gear portion 42 and the inner ring 43 have been described as separate parts, it is also possible to adopt a first gear portion incorporating a part corresponding to the inner ring 43. In this way, the configuration of the gear G10 incorporating the one-way clutch can be modified as appropriate.

In addition, although a one-way clutch 45 is provided as a transmission unit that transmits power only during forward transport, other transmission units may be provided. For example, a magnetically actuated clutch may be provided, and power may be transmitted by passing electricity only during forward transport.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and includes the inventions described in the claims and their equivalents. The inventions described in the original claims of this application are described below.

(Additional Note)
(Appendix 1)
a transport unit capable of transporting the print medium and the ink ribbon in a first direction and a second direction;
a ribbon take-up shaft that takes up the ink ribbon when the ink ribbon is transported in the first direction by the transport unit;
a drive source that outputs power for operating the conveying unit and the ribbon winding shaft;
a first drive mechanism that transmits power output by the drive source to the transport unit;
a second drive mechanism having a transmission section that transmits the power output by the drive source to the ribbon take-up shaft when the ink ribbon is transported in the first direction, and does not transmit the power output by the drive source to the ribbon take-up shaft when the ink ribbon is transported in the second direction,
When the ink ribbon is transported in the second direction, the ink ribbon is pulled out from the ribbon take-up shaft by the power transmitted to the first drive mechanism.
A printing device comprising:

(Appendix 2)
The transmission unit is a one-way clutch.
2. The printing device according to claim 1 .

(Appendix 3)
the second drive mechanism has a plurality of gears for transmitting the power output by the drive source,
The one-way clutch is incorporated into the plurality of gears.
3. The printing device according to claim 2.

(Appendix 4)
the ribbon take-up shaft is connected to the second drive mechanism via a torque limiter,
the second driving mechanism transmits to the torque limiter a rotational motion faster than a speed at which the ink ribbon is transported in the first direction;
4. The printing device according to claim 1,

(Appendix 5)
The torque limiter is a felt type,
the ribbon winding shaft winds up the ink ribbon while causing a felt to slip when the torque applied to the torque limiter exceeds a threshold value;
5. The printing device according to claim 4.

(Appendix 6)
a step of conveying the ink ribbon in the second direction before printing on the print medium, thereby shortening a margin formed at an edge of the print;
6. A printing device according to claim 1,

(Appendix 7)
the first direction is a direction in which the print medium is discharged outside the device,
The second direction is opposite to the first direction.
7. A printing device according to claim 1,

(Appendix 8)
the transport unit includes at least a thermal head that prints on the print medium, and a platen roller that rotates to transport the print medium and the ink ribbon;
the ink ribbon is conveyed while being sandwiched between the thermal head and the platen roller;
8. A printing device according to claim 1,

(Appendix 9)
a rotation speed of the platen roller when transporting the ink ribbon in the first direction is slower than a rotation speed of a gear connected to the ribbon take-up shaft;
9. The printing device according to claim 8.

1: Printing device, 2: Housing, 2a: Flat surface, 2b: Curved surface, 2c: Recess, 2d: Discharge port, 8: Main part, 10: Thermal head, 11: Base part, 11a: Flat plate part, 12: Cartridge holding part, 12a: Holding part main body, 12b: Legs, 12c: Cartridge storage part, 16: Half cutter, 17: Full cutter, 21: Platen roller, 21a: Shaft, 22: Tape core engagement shaft, 23: Ribbon winding shaft, 24: Motor, 25: Shaft part, 25a: Flange part, 26: Engagement part, 27: Torque limiter 27a...rotating part, 27b...felt, 28...spring, 29...protruding part, 30...tape cartridge, 31...cartridge case, 32...tape core, 34...ribbon supply core, 35...ribbon take-up core, 36...thermal head insertion part, 41...rotating shaft, 42...first gear part, 42a...protruding part, 42b...gear main body part, 43...inner ring, 44...outer ring, 45...one-way clutch, 46...second gear part, G1...output gear, G2-G12...gear, M...tape member, R...ink ribbon, MA...margin

Claims (3)

a platen roller that rotates while pressing the print medium and the ink ribbon between the platen roller and a thermal head, thereby transporting the print medium and the ink ribbon in a forward transport direction and a reverse transport direction;
a take-up core around which the ink ribbon is drawn out from a roll body wound around a supply core and wound again when the ink ribbon is transported in the forward transport direction by the platen roller ;
A drive source that outputs rotational power;
a first drive mechanism that transmits a rotational power output by the drive source to the platen roller as a rotational power for the platen roller ;
a second drive mechanism that transmits the rotational power output by the drive source to a rotational shaft having a predetermined engaging portion that is inserted into and engaged with the take-up core of the supply core and the take-up core, as the rotational power of the rotational shaft, causing the ink ribbon to be wound around the take-up core;
Equipped with
The second drive mechanism is
a one-way gear is provided in the middle of a path along which the rotational power output by the drive source is transmitted to the rotation shaft, the one-way gear transmitting the rotational power output by the drive source in a direction corresponding to the forward transport direction while blocking the rotational power in a direction corresponding to the reverse transport direction, so that when the ink ribbon is transported in the reverse transport direction , the ink ribbon is pulled out from the take-up core only by the rotational power transmitted to the platen roller out of the rotational power output by the drive source,
and,
a rotation speed of the rotation shaft generated by pulling out the ink ribbon from the take-up core is configured to be slower than a rotation speed of the rotation shaft when a rotational power in a direction corresponding to the forward transport direction is transmitted from the drive source via the second drive mechanism.
A printing device comprising: The rotating shaft has a felt type torque limiter that suppresses rotation at the engagement portion by slipping a felt when the torque to the engagement portion exceeds a threshold value.
2. The printing device according to claim 1. the positive transport direction is a direction in which the print medium is discharged outside the device,
The reverse transport direction is a direction in which the print medium is returned into the device.
3. The printing apparatus according to claim 1, wherein the first and second printing units are arranged in a first direction.

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