JPS61280981A - Apparatus for changing over position of ribbon - Google Patents

Abstract

PURPOSE:To obtain a ribbon position change-over apparatus capable of accurately determining the change-over of a ribbon, by cooperating a guide shaft along with a guide member by a connection link so as to move the guide member to the same direction corresponding to the moving amount of a ribbon base and regulating the length of the connection link even if the distance between the rotation center of a cam and that of the connection lever gets out of order. CONSTITUTION:A guide shaft 8 for guiding a guide member 10, which guides a ribbon to a running direction, in parallel to a platen 3 in a freely slidable manner is mounted and cams 14 supporting both sides of a ribbon case 3 are connected to gears 11, 12 driven by a motor 13 to be arranged on the same axis. First links 20 contacted with the cams 14 at one ends and having slots 25 formed to the other ends thereof and second links 21 connected to both ends of the guide shaft 8 at one ends thereof are provided and both first and second links 20, 21 are connected in the slots 25 by screws 24 to form connection links 22 freely extensible and contractable and freely fixed in an arbitrarily length and the second links 21 are mounted to the shaft 19 protruded to the slots 25 so as to be freely revolved to the same direction as the revolving direction of the ribbon base 5.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a ribbon position switching device.

Conventional technology Conventionally, a ribbon cassette for multiple colors is provided in which ribbons that are color-coded into multiple zones are stored in a cassette case, and a ribbon base that holds this ribbon cassette is rotated to an arbitrary position to select the desired color zone. There is one that prints in multiple colors facing the printing position.

Also, a method is often used in which the rotation of a motor is transmitted to a cam via a gear, and the ribbon base is rotated by the cam.

Problems to be Solved by the Invention Because backlash occurs in the gear that transmits the rotation of the motor to the cam, the position of the ribbon base changes every time the direction of rotation of the motor changes even if the same position is aimed. Therefore, some margin must be made for the width of the zone.

This invention was made in view of these points.

An object of the present invention is to provide a ribbon position switching device that can accurately determine the ribbon switching position.

Means for Solving the Problems In the present invention, a guide shaft 8 is installed to slidably guide a guide member 10 for guiding the ribbon 4a in the running direction parallel to the platen 3, and both sides of the ribbon base 3 are Supporting cam 1
4 are connected to gears 11 and 12 driven by a motor 13 and arranged coaxially, one end abuts the cam 14 and the other end has a long hole 2.
5, and a second link 21 whose one end is connected to both ends of the guide shaft 8. 2
4 to form a continuous rod 22 that can be expanded and contracted and fixed to any length, and a second link 21 is rotated in the same direction as the rotation direction of the ribbon base 5 around the shaft 19 that projects into the elongated hole 25. Install freely.

When the action cam 14 rotates, the ribbon base 5 rotates, the connecting rod 22 also rotates, and the guide shaft 8 rotates together with the guide member 1o in the same direction as the ribbon base 5. The cam 14 is stationary at a predetermined position and the ribbon base 5 and guide member 10 are stationary at a desired position, but the screw 24 is retightened and the connecting rod 22
By adjusting the length of , the distance from the pivot point of the connecting rod 22 to the contact position with respect to the cam 14 is determined. Therefore, the positions of the ribbon base 5 and the guide member 1o are maintained accurately.

Further, although the links 20, 21 are connected by only one screw 24, the shaft 19 protruding into the elongated hole 25 is used to prevent the connecting portion of the links 20, 21 from breaking into a dogleg.

Example An embodiment of the present invention will be described based on the drawings.

A platen 3 is rotatably held by opposing frames 1 and 2. A ribbon base 5 that removably holds a ribbon cassette 4 is rotatably held on these frames 1 and 2 about a shaft 6 as a fulcrum. In FIG. 1, a part of the left frame 1 and the left side of the ribbon base 5 are shown cut away, but the frames 1 and 2 rotatably hold the drive shaft 7, and both ends of the guide shaft 8 are moved up and down. A long hole 9 for movably holding is formed. Also, frame 1.
Although not shown in the drawings, a carrier shaft 2 is installed to slidably hold a carrier on which a printing section is mounted along the platen 3. A guide member 10 that guides the ribbon 4a of the ribbon cassette 4 in a running direction parallel to the platen 3 is slidably held on the guide shaft 8. This guide member 10
is also held in the carrier described above so as to be slidable in a direction perpendicular to the ribbon running direction.

A gear 11 is fixed to the left end of the drive shaft 7.
A gear 12 meshed with is directly connected to a motor 13.

Further, cams 14 are fixed to both ends of the drive shaft 7, and concave locking portions 15, 16, 17 .
18 are formed. Further, shafts 19 are erected on the outside of the frames 1 and 2, and a connecting rod 22 connecting a first link 2o and a second link 21 is rotatably held on these shafts 19. ing. That is, the second link 21
is rotatably held on a shaft 19, and a guide shaft 8 is attached to the tip.
A notch 23 is formed to fit into the. first link 2
0 is formed with an elongated hole 25 for passing a screw 24 that is slidably fitted onto the shaft 19 and is screwed onto the link 21, and the locking portions 15, 16, 17, and 18 of the cam 14 are A pin 26 that engages with either is provided upright. Both ends of the guide shaft 8 are urged downward by a spring 27.

Furthermore, a drive shaft 29 is provided which is detachably engaged with the ribbon winding shaft 28 of the ribbon cassette 4.

In such a configuration, when the carrier is moved along the platen 3, the guide member 10 is also guided by the guide shaft 8 and moves along the platen 3 to a desired printing position. When the motor 13 is driven and the cam 14 is rotated, the ribbon base 5 rotates about the shaft 6. At this time, the connecting rod 22 rotates about the shaft 19 as a fulcrum.

The guide shaft 8 moves together with the guide member 10 in the same direction in accordance with the amount of movement of the ribbon cassette 4. The ribbon base 5 rotates about an axis 6, while the guide shaft 8 and the guide member 10 move in a vertical plane parallel to the front surface of the print head (see FIGS. 4 to 7), thus: No matter which zone of the ribbon 4a is located at the printing position ff1A, the distance between that zone and the platen 3 can be set at an appropriate constant distance.

At this time, the cam 14, which is stationary at a predetermined position, has a locking portion 15,
Since gears 11, 17, and 18 engage the pin 26, gears 11, 12
The cam 14 does not move in the rotational direction regardless of the presence or absence of backlash.

In addition, the force of the spring 27 increases the engagement force with the pin 26 and the cam 1
4 movement is effectively prevented.

Further, the distance from the shaft 19 to the pin 26 can be changed by loosening the screw 24, sliding the link 20 relative to the link 21, and tightening the screw 24 again to adjust the length of the connecting rod 22. Therefore, force 1114 and connection 22
Even if the center distance between the guide member 10 and the guide member 10 is incorrect, the range of rotation of the connecting rod 22 can be adjusted to make the ribbon switching position, that is, the position of the guide member 10 extremely accurate.

Also, the first and second links 20 and 21 are connected by one screw 2.
4, but the shaft 19 projects into the elongated hole 25.
By using this, it is possible to prevent the connecting portions of the links 20 and 21 from breaking into a dogleg shape, and the structure and assembly work of the connecting rod 22 can be simplified.

Effects of the Invention Since the present invention is configured as described above, when the cam is rotated to rotate the ribbon base to the desired ribbon switching position, the guide shaft is moved along with the guide member by the connecting rod to correspond to the amount of movement of the ribbon base. can be linked in the same direction,
Therefore, by moving the guide member in a plane parallel to the front surface of the print head, no matter which zone of the ribbon faces the printing position, the distance between that zone and the platen can be set at an appropriate and uniform distance. , even if the distance between the rotation center of the cam and the rotation center of the connecting rod is incorrect, the length of the connecting rod is W! 4ff
l! The cylinder switching position can be maintained extremely accurately.Furthermore, although the first and second links are connected with only one screw, the connecting part of the links can be easily fixed by using the shaft protruding into the elongated hole. It has effects such as being able to prevent bending in the shape of a square, and simplifying the structure and assembly work of the connecting rod.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a perspective view, and FIG. 2 is a partially enlarged side view of the ribbon base in its lowest position. FIG. 3 is a partial side view showing the ribbon base in its highest position in an enlarged manner; FIGS. 4 to 7 are partial side views showing the lifting and lowering movement of the ribbon base; FIG. 9 is a horizontal sectional view showing the support structure of the connecting rod, and FIG. 9 is an exploded perspective view of the connecting rod. 3...Platen, 4...Ribbon cassette, 4a...
・Ribbon, 5... Ribbon base, 8... Guide shaft, 1
0...Guide member, 11.12...Gear, 13...
Motor, 14... cam, 19... shaft, 20... first link, 21... second link, 22... connecting rod, 24... screw, 25... length hole

Claims (1)

[Claims] A ribbon base holding a multi-color ribbon cassette is rotatably provided in a direction perpendicular to the longitudinal direction of the platen, and a carrier holding a printing part and moving along the platen or the printing part holds the ribbon cassette. A guide member for guiding the running of the ribbon is connected to be movable in a straight line orthogonal to the running direction of the ribbon, a guide shaft is provided for slidably guiding the guide member parallel to the platen, and the ribbon base A first cam is connected to a gear driven by a motor and arranged coaxially, and one end abuts the cam and a long hole is formed in the other end. A link and a second link having one end connected to both ends of the guide shaft are provided, and the first and second links are connected in the elongated hole with a single screw to be expandable and contractible and fixed to an arbitrary length. A ribbon position switching device characterized in that a freely continuous rod is formed and the second link is attached to a shaft protruding from the elongated hole so as to be rotatable in the same direction as the rotation direction of the ribbon base.