JPH0463789B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a ribbon feeding device for a printer.

Technical background of the invention and its problems Conventionally, a carrier is provided with a ribbon support stand that holds a ribbon cassette so as to be movable up and down, and this ribbon support stand is placed at either the printing position, the erasing position using the collect ribbon, or the print confirmation position. Select it and move it up or down.
In the case of multi-color printing, there are devices in which the ribbon support is moved up and down in order to obtain the desired print color. The first means of driving the ribbon cassette on the ribbon support stand is to mount a ribbon feed motor on the ribbon support stand, but since the ribbon support stand becomes heavy, a motor with a large capacity is used as a drive unit to move the ribbon support stand up and down. It has the disadvantage that it requires a solenoid and is not suitable for high-speed operation. There are also difficulties in wiring and assembly work. As a second method, there is a method in which a carrier is provided with a ribbon feed motor and a ribbon feed shaft driven by the motor, but this has the disadvantage that power transmission lacks smoothness because the vertical position of the ribbon support base changes. .

For this reason, the devices shown in FIGS. 1 to 6 can be considered as solutions to the above-mentioned drawbacks. First, a carrier 1 is held by a carrier shaft 2 so as to be slidable parallel to a platen 3. The carrier 1 is equipped with a daisy wheel 5 driven by a wheel motor 4 and a printing hammer (not shown) driven by a solenoid (not shown) as a printing section. Further, a ribbon support 6 is attached to the carrier 1 so as to be movable up and down about a support shaft 7. A fan-shaped gear 8 with a support shaft 7 as the center of its radius is fixed to the ribbon support 6, and the carrier 1 includes a lifting motor 9 serving as a drive unit, a gear 10 that transmits the rotation of the motor 9 to the gear 8, 11 has been taken. A ribbon cassette 12 is detachably attached to the ribbon support 6, and a pair of left and right spools 1 are attached to the ribbon cassette 12.
3 is retained. A part of the printing ribbon 14 pulled out from the ribbon cassette 12 faces the front surface of the platen 3, and a part of the collection ribbon 15, whose both ends are wound around the spool 13, faces the platen 3 on the lower side of the printing ribbon 14. ing.

Next, the carrier 1 is equipped with a ribbon feed motor 16.
and a drive gear 17 are provided to be directly connected to each other,
The drive gear 17 has a perpendicular axis, and the ribbon feed gear 18 and the ratchet 1 have parallel axes.
9 is provided. As shown in FIG. 5, the shaft portion 20 of the ribbon feed gear 18 is slidably and rotatably fitted into a bush 21 inserted into the carrier 1, and the upper portion of the shaft portion 20 is fitted into a hole formed in the center of the ratchet 19. 22 so as to be rotatable. A linear engaging portion 23 is formed at the upper end of the ratchet 19, and this engaging portion 23 protrudes from an opening 24 formed in the ribbon support base 6.
It is removably engaged with a groove 26 formed at the lower end of the holder 5. These ribbon feed gear 18 and ratchet 19 are urged upward by a spring 27, but because the stepped portion 28 of the ratchet 19 is in contact with the lower surface of the ribbon support base 6, excessive upward movement is prevented. It is blocked. Ratchet teeth 29 are formed on opposing surfaces of the ratchet 19 and the ribbon feed gear 18 to transmit rotation in one direction.

In such a configuration, by driving the lifting motor 9 and transmitting its rotation to the gear 8, the ribbon support base 6 is rotated about the support shaft 7. Second
The figure shows the center of the rotation range, that is, the printing position. FIG. 3 shows the printing confirmation position where the ribbon support stand 6 has been rotated to the lower stage. FIG. 4 shows the erasing position in which the ribbon support 6 is rotated upward so that a part of the collection ribbon 15 faces the tip of the daisy wheel 5. Although only a portion is shown, FIG. 5 shows the print confirmation position, and FIG. 6 shows the erasure position.

To feed the printing ribbon 14, use the ribbon feed motor 1.
6 is driven, and its rotation is transmitted from the drive gear 17 to the ribbon feed gear 18, the ratchet 19, and the ribbon feed shaft 25 in this order. At this time, when the ribbon support stand 6 moves up and down, the ribbon feed gear 18 and the ratchet 19 move up and down accordingly, and the groove 26 of the ribbon feed shaft 25 and the engaging part 2 of the ratchet 19 move up and down.
3 are maintained in an engaged state. Since the ribbon feed gear 18 and the drive gear 17 always mesh with each other with parallel axes, rotation transmission between the two is performed smoothly. Further, even if the ribbon cassette 12 is tilted, the groove 26 at the lower end of the ribbon feed shaft 25 is located on the same axis as the ribbon feed gear 18 and the ratchet 19, so that the rotation is transmitted from the ribbon feed gear 18 to the ribbon feed shaft 25. is also carried out smoothly. In this case, the axis of the ribbon feed shaft 25 is as shown in FIGS.
As shown in the figure, since the groove 26 is inclined with respect to the axis of the ratchet 19, it is preferable to make the width of the groove 26 a little wider than the width of the engaging portion 23 with some margin.

Further, the drive gear 17 and the ribbon feed motor 16 can be arranged at arbitrary positions around the drive gear 18 and at arbitrary positions in the vertical direction, regardless of the support shaft 7. Since the ribbon feed motor 16 is attached to the carrier 1 in this way, the ribbon support stand 6 can be driven by a small capacity lifting motor 9 or a solenoid (not shown).
It is possible to reduce the weight and increase the speed of operation.

In such a structure, by providing a ribbon feed motor for feeding the ribbon in the carrier, the capacity of the drive unit that raises and lowers the ribbon support platform is reduced, thereby reducing weight and increasing operating speed. In addition, the ribbon feed gear and the ratchet can be raised and lowered parallel to the axis of the drive shaft in response to the raising and lowering movement of the ribbon support base, so that the engaging part of the ratchet is always located directly below the ribbon feed shaft in the ribbon cassette. By facing each other, the rotation is smoothly transmitted from the drive gear to the ribbon feed gear, and
Coaxial rotation can be smoothly transmitted from the ribbon feed gear to the ribbon feed shaft in the ribbon cassette.

Purpose of the Invention The present invention aims at reducing the weight of the carrier and increasing the speed of operation by raising and lowering the ribbon support using a drive unit with a small capacity. It is an object of the present invention to provide a ribbon feeding device for a printer that can smoothly feed the ribbon by reducing the size of the ribbon.

SUMMARY OF THE INVENTION The present invention includes a ribbon support that holds a ribbon cassette that is movably mounted on a carrier that moves along a platen, and a drive unit that moves the ribbon support up and down. A drive gear that is connected to the ribbon feed motor and rotates with a substantially vertical axis is provided, and a ribbon feed gear that is constantly meshed with the drive gear is biased upward so that it can freely slide in the vertical and axial directions. A ratch is rotatably supported by the carrier and has an engaging portion formed at its upper end to removably engage with the lower end of the ribbon feed shaft in the ribbon cassette, and this ratch is connected to the upper center of the ribbon feed gear. The ribbon feed gear and the ratchet are connected to each other by a coil spring so as to be swingable in a direction perpendicular to the rotational axis, and the ribbon feed gear and the ratchet are connected to each other so as to be able to swing freely in a direction perpendicular to the rotational axis, and to transmit only the rotational force of the ribbon feed gear in one direction to the ratchet. Ratchet teeth that engage with each other are formed on the opposing surfaces of the teeth.

Therefore, since the ratchet and the ribbon feed gear are connected so that they can swing freely in the direction perpendicular to the rotation axis, the ratchet can feed the ribbon even if the clearance between the engaging part of the ratchet and the ribbon feed shaft is small. By tilting to follow the tilt of the support base, a secure engagement state can be maintained. This allows the ribbon to be fed without any play, and the rotation of the ratchet can be smoothly adjusted to the ribbon feed shaft. It is something that can be transmitted to

Embodiment of the Invention An embodiment of the invention will be described with reference to FIGS. 7 and 8. Components that are the same as those shown in FIGS. 1 to 6 are designated by the same reference numerals, and description thereof will be omitted. In this embodiment, the diameter of the hole 22 of the ratchet 19 is made approximately larger than the diameter of the upper part of the shaft portion 20 of the ribbon feed gear 18, and a coil spring 30 is compressed between the ratchet 19 and the ribbon feed gear 18. It is equipped.

Therefore, although the ratchet 19 is urged upward, since the stepped portion 28 is in contact with the ribbon support 6, the ratchet teeth 29 are always maintained in a meshed state. When the ribbon support stand 6 is tilted as shown in FIG. 8, the ratchet 19 is tilted with respect to the axis of the ribbon feed gear 18 and coincides with the axis of the ribbon feed shaft 25. Therefore, the rotation of the ratchet 19 can be smoothly transmitted to the ribbon feed shaft 25 by reducing the clearance between the engaging portion 23 and the groove 26.

In addition, ribbon feed gear 18 and ratchet 1
9, the rotation is transmitted in only one direction by the ratchet teeth 29, so the ribbon feed shaft 25 whose tip protrudes from the top surface of the ribbon cassette 12 can be rotated with a small force by hand.
To eliminate slack in the printing ribbon 14 on the front surface of the printer. The printing ribbon 14 is fed at the printing position shown in Figure 2 or the printing confirmation position shown in Figure 3, but if a multicolor printing ribbon is used, the ribbon is fed at each of the upper, middle, and lower positions of the ribbon support 6. I will do it.

Effects of the Invention Since the present invention is configured as described above, the ribbon feed motor can be removed from the ribbon support base and the ribbon support base can be raised and lowered by a drive unit with a small capacity, thereby reducing the weight and increasing the speed of operation. In addition, regardless of the position of the ribbon support base, the drive gear and ribbon feed gear can be meshed with parallel axes to smoothly transmit rotation between the two. Regardless of the position of the ribbon support base, the engaging part of the ratchet can be positioned directly below the ribbon feed shaft of the ribbon cassette, and the rotation of the ribbon feed gear can be smoothly transmitted to the ribbon feed shaft on the same axis. By interposing a coil spring between the ribbon feed gear and the ratchet, the axis of the ratchet can be tilted in line with the axis of the ribbon feed shaft according to the tilt of the ribbon support base. This has the advantage that rotation can be smoothly transmitted from the ribbon feed shaft to the ribbon feed shaft, and the mounting position of the ribbon feed motor can be freely determined.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an example of a structure that can be implemented as a solution to the conventional drawbacks, FIGS. 2 to 4 are side views showing the raising and lowering movement of the ribbon support, and FIGS. 5 and 6. 1 is a partially enlarged vertical sectional side view showing the lifting and lowering movement of the ribbon support and the power transmission path, and FIGS. FIG. 3 is a partially enlarged longitudinal side view showing a route. 1... Carrier, 3... Platen, 6... Ribbon support stand, 9... Lifting motor (drive unit), 12
... Ribbon cassette, 16 ... Ribbon feed motor, 17 ... Drive gear, 18 ... Ribbon feed gear, 19 ... Ratchet, 23 ... Engagement part, 2
5...Ribbon feed shaft, 29...Ratchet tooth, 3
0...Coil spring.

Claims (1)

[Claims] 1. A ribbon support stand that holds a ribbon cassette is attached to a carrier that moves along a platen so as to be able to move up and down, and a drive unit that moves this ribbon support stand up and down is attached, and a ribbon feed motor is connected to the carrier and this ribbon feed motor is attached. and a drive gear that rotates with a substantially perpendicular axis, and a ribbon feed gear that constantly meshes with the drive gear is biased upward to allow the carrier to slide and rotate in the vertical and axial directions. a ratch having an engaging portion formed at an upper end to support the ribbon feeding shaft and detachably engage the lower end of the ribbon feeding shaft in the ribbon cassette;
This ratchet is connected to the center of the upper part of the ribbon feed gear by a coil spring so that it can swing freely in a direction perpendicular to the rotational axis, so that only the rotational force of the ribbon feed gear in one direction is transmitted to the ratchet. A ribbon feeding device for a printer, characterized in that ratchet teeth that mesh with each other are formed on opposing surfaces of the ribbon feed gear and the ratchet.