JPH0465281A - printing device - Google Patents

Abstract

PURPOSE:To enable a ribbon driving gear to be rotated always in one direction by a method wherein a rotary transmission gear and a rotary transmission gear holding arm are engaged with each other by a highly elastic sheet. CONSTITUTION:In the case where a carriage 19 is moved right, a rotary transmission gear 11 installed on the carriage 19 to be engaged with a toothed plate 21 of a body is rotated in the direction A. An arm 2 is moved in a direction in which the arm 2 is engaged with a planet gear 16 of a gear train (a) by using a shaft 2a of the arm 2 as a fulcrum by friction torque generated between the gear 1 and a highly elastic sheet 13 by its rotary torque, and a ribbon driving gear 15 is clockwise rotated via the planet gear 16. Further, in the case where the carriage 19 stops and is moved in a reversed direction, reversal friction torque is generated between the rotary transmission gear 11 and the highly elastic sheet, the arm 2 is moved in a direction of being engaged with a gear train (b), and the ribbon driving gear 15 is rotated in the same direction as beforehand via planetary gears 17, 18.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention involves placing an ink ribbon containing ink on a carriage, and transferring the ink on the ink ribbon to a print medium such as paper while feeding out the ink ribbon. The present invention relates to a printing device that performs printing.

2. Description of the Related Art Impact-type printing devices have been the mainstream of printing devices as output devices for computers and the like since they have the practical advantages of being able to make copies and having low running costs. The printing carriage of these printing devices employs a one-way ink ribbon mechanism. In the conventional one-way mechanism, a metal spring was used in the rotation transmission gear to generate rotational movement torque in the planetary gear or the like.

The one-way mechanism of a conventional printing device will be explained below.

FIG. 6 is a sectional view of a main part of a conventional printing device. 1 is a rotation transmission gear that rotates by meshing with a toothed plate of the printing device, and 2 is a rotation transmission gear holder that holds the gear and has the function of reversing the rotation direction of the gear about the shaft 2a. An arm, 3 is a metal spring loosely fitted to the rotation transmission gear holding part 2b of the arm, and 4 is a screw that engages the rotation transmission gear l and the rotation transmission gear holding part 2b via the spring 3. .

The operation of the conventional printing device configured as described above will be described below. In order to generate a rotational torque in the rotation transmission gear 1 that reverses the arm 2 using the shaft 2a of the rotation transmission gear holding arm 2 as a fulcrum, the contact surface between the spring 3 and the rotation transmission gear 1 and the screw are pressed by the biasing force of the spring 3. The friction torque generated at the contact surface between the gear 4 and the gear 1 was utilized.

Problems to be Solved by the Invention However, in the conventional configuration described above, the contact area between the flange of the screw 4 and the rotary drive gear 1 is small, so it is difficult to generate a large friction torque. Further, during use of the printing device, the metal spring 3 may be twisted, making it difficult to apply a constant friction torque. If we try to improve these and provide a large and constant friction torque, the pressing force of the spring 3 will damage the contact surfaces of the rotation transmission gear 1 and the rotation transmission gear support arm 2, etc. Furthermore, the hole for accommodating the spring 3 of the rotation transmission gear 1 must be enlarged, which complicates the structure and impairs workability.

Means for Solving the Problem In order to solve this problem, the present invention uses a highly elastic thin plate instead of a metal spring that biases the rotation transmission gear, and uses the elastic force of the thin plate to transmit rotation. It is designed to energize a wide area of the gear.

action With the above configuration, the present invention has the following effects.

(1) A large contact area can be obtained between the rotation transmission gear and the highly elastic thin plate, making it possible to obtain a large rotational torque.

(2) Since the elastic force of the highly elastic thin plate does not change at all times, stable rotational torque can be obtained.

(3) Less wear on parts and improved durability.

(4) The structure is simplified and workability is improved.

Embodiment FIG. 1 is a bottom view of a carriage incorporating a rotation transmission gear according to an embodiment of the present invention, and FIG.
-A line sectional view, FIG. 3 is a perspective view of the main parts of the printing device equipped with a carriage, FIG. 4 is a sectional view of the main parts of the printing device, and FIG. 5 is the ink ribbon drive mechanism. FIG. 2 is a bottom view of essential parts. 2 is a rotation transmission gear holding arm, 4
are screws, and since these have the same configuration as the conventional one, their explanation will be omitted. 11 is a rotation transmission gear loosely fitted into the rotation transmission holding part 2b of the holding arm 2, and 13 is a highly elastic thin plate having flexure and fixed to the gear 11 with screws 4 in order to apply left and right rotational torque to the arm. And! 5 is a ribbon drive gear that transmits power to the ribbon cassette and feeds the ribbon, 16, 17, and 18 are planetary gears that transmit power to the ribbon drive gear, and 19 holds the gear train. , a carriage that carries an ink ribbon cassette.

In FIG. 3, 20 holds the carriage 19;
A carriage shaft 21 for moving left and right is a toothed plate that meshes with the rotation transmission gear 11.

It also consists of a print head section that prints on a print medium, a platen section for feeding the print medium, and a tractor section. In FIG. 4, the rotation transmission gear 11 is composed of large, medium and small concentric cylindrical bodies, and the outer peripheries of the large cylindrical part la and the small cylindrical part 1b are provided with a clutch system for transmitting rotational force to the ribbon drive gear 15. teeth are formed and loosely fitted into the holding portion 2b of the arm 2 in the central hole 1c. A concentric recess 1d is formed on the upper surface of the large cylindrical portion 1a. The holding part 2b has a cylindrical shape, and is formed to be higher than or about the same level as the central hole 1c, and lower than the upper surface of the recessed part 1d of the gear 11, and a threaded groove for screwing with the screw 4 is formed on the upper surface. ing. The highly elastic thin plate 13 is made of a disc-shaped material such as a highly elastic resin, hard rubber, or metal such as steel, and has a thickness that provides an optimum elastic force. Further, it is preferable to insert a spacer between the rotation transmission gear 11 and the rotation transmission gear holding arm 2 because the rotation of the gear 11 becomes smooth.

Regarding the printing device of this embodiment configured as described above,
The operation will be explained below. - When the carriage 19 (not shown) moves to the right in Figure 5 (a),
Carriage 19 (
The rotation transmission gear 11 (not shown) provided above rotates in the inward direction.

Due to the frictional torque generated between the gear 11 and the highly elastic thin plate 13 due to the rotational torque, the arm 2 moves in the direction of meshing with the planetary gear 16 of the gear train a, using the shaft 2a of the arm 2 as a fulcrum, and the planetary gear 16 to rotate the ribbon drive gear 15 clockwise. In addition, in FIG. 5(b), when the carriage 19 stops and moves in the opposite direction, a friction torque opposite to that described above is applied to the rotation transmission gear 1.
1 and the highly elastic thin plate 13, the arm 2 moves in the direction of meshing with the gear train b, and via the planetary gears 17 and 18,
The ribbon drive gear 15 is rotated in the same direction as before. Ribbon drive gear 15 in addition to the 2 gear trains
may be one or more gears as long as they always rotate in a constant direction.

Effects of the Invention The present invention provides a one-way mechanism in which the driving force of the rotation transmission gear is transmitted to the gear train using a clutch method in order to always rotate the ribbon drive gear in one direction regardless of the moving direction of the carriage. By using the elastic force of the elastic thin plate, it is possible to apply a stable and large frictional torque to the rotation transmission gear, and as a result, the ink ribbon can be reliably fed in a fixed direction even if the direction of carriage movement changes. The ink ribbon is reliably fed even during reciprocating printing with a small number of printed characters, providing high printing quality, and is easy to handle, greatly improving workability during assembly.

[Brief explanation of the drawing]

FIG. 1 is a bottom view of a carriage incorporating a rotation transmission gear according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A-A in FIG. Fig. 4 is a sectional view of the main parts of the printing device, Fig. 5 is a perspective view of the main parts of the printing device.
The figure is a bottom view of a main part showing an ink ribbon drive mechanism, and FIG. 6 is a sectional view of a main part of a conventional printing device. Fig. 1 "A 1.11...Rotation transmission gear 2...Rotation transmission gear holding arm 4...Brew 13...Highly elastic thin plate 15...Ribbon drive gear 16.17.18... Planetary gear 19... Carriage agent's name Patent attorney Shigetaka Awano 1 person - A Figure Figure Figure Figure

Claims (1)

[Scope of Claims] A carriage equipped with a print head, an ink ribbon drive shaft that feeds the ink ribbon placed on the carriage, and one or more gear trains that drive the ink ribbon drive shaft in a fixed direction. a rotation transmission gear that applies driving force to the gear train using a clutch method; a rotation transmission gear holding arm that holds the rotation transmission gear; and a highly elastic thin plate that engages the rotation transmission gear and the rotation transmission gear holding arm. A printing device characterized by having the following.