JPS61230971A - Apparatus for changing over position of ribbon - Google Patents

Abstract

PURPOSE:To easily determine the home position of a mount stand and to make it possible to also easily perform the matching of a stepping motor, by providing at least two gears in a power transmission route and forming a notch for releasing the meshing of teeth to one of said gears. CONSTITUTION:When a stepping motor 10 is driven, a cam 8 is rotated to revolve a mount stand 5 in an up-and-down direction. When the pin 9 of the mount stand 5 is successively lifted to control parts 19, 20, 21, 22, the mount stand 5 is displaced as shown by positions (a), (b), (c), (d) to perform the change- over of a color. when the pin 0 is supported by the control part 22, the mount stand 5 is positioned at the change-over position (d) and, when a stepping motor 10 is driven from this state with 39 steps corresponding to 3 times one pitch (p) between the control parts to rotate the cam 8 to a counterclockwise direction, a notch 23 is opposed to a gear 11 to release the meshing of gears 11, 12. The rotational inertia of the cam 8 at this time is also lost by a leaf spring 25 and the cam 8 only reciprocally moves minutely in the range of one step or less of the stepping motor 10 even if the teeth of the gears 11, 12 contact with each other slightly and is not rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a ribbon position switching device used in a printing machine.

Conventional technology Conventionally, a mounting table that removably holds a multicolored ribbon cassette having ribbons that are color-coded into multiple zones is connected to a carrier so that it can move up and down, and the rotation of a step motor is controlled by a gear on the mounting table. There is a system in which each zone of the ribbon is made to face the printing section by transmitting the signal to the printer to rotate the mounting table, determining the home position of the mounting table, and driving a step motor with a fixed number of steps.

Problems to be Solved by the Invention However, the adjustment work is extremely difficult because the step motor alignment and the home position adjustment of the mounting table must be performed at the same time.

The present invention has been made in view of the above points, and an object of the present invention is to extremely easily adjust the home position of the mounting table and match the step motor, and to move the ribbon position switching device.

Means for Solving the Problems In the present invention, a mounting table 5 holding a multicolored ribbon cassette 13 having ribbons 14 color-coded into a plurality of zones 15 to 18 is movably connected to a carrier 1.
A cam 8 is connected to a step motor 10 to displace the mounting table 5 in a direction perpendicular to the moving direction of the carrier 1.
A plurality of control parts 19 to 22 are formed on the cam 8 to position the mounting table 5 at each switching position so that the zones 15 to 18 of the ribbon 14 are opposed to the printing part 4, respectively.

The lengths of the control units 19 to 22 are set to correspond to the number of steps of the step motor 10, and the step motor 1
At least two gears 11.12 are provided in the power transmission path from 0 to the cam 8, and at least one of these gears 11.12 is formed with a notch 23 for disengaging the teeth at the home position of the mounting table 5.

The cam 8 is rotated by the operation step motor 10 to displace the mounting table 5, so that zones 15 to 18 of arbitrary colors of the ribbon 14 of the multicolor ribbon cassette 13 are opposed to the printing section 4.

No matter what position the mounting table 5 is in, as long as the step motor 10 is driven, it will be displaced and reach the home position, and at this time the gears 11 and 12 will be disengaged due to the formation of the notch 23. Therefore, by specifying a certain phase and driving the step motor 10 with a margin for the number of steps, the home position of the mounting table 5 can be determined, and the step motor 10 can also be phased.

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

A printing unit 4 is provided which includes a print head 2 mounted on a carrier 1 and a platen 3. A mounting table 5 is rotatably held on the carrier 1 by a shaft 6. Further, a cam 8 having a protruding spiral 7 formed on its outer periphery is held on the carrier 1 so as to be rotatable about its axis in the moving direction of the mounting table 5. A pin 9 for holding the spiral 7 is provided upright on the right side of the mounting table 5.

Next, the support stand 1a is detachably attached to the carrier 1.
is provided with a step motor 10 that can freely rotate in forward and reverse directions and a gear 11 that is directly connected to the step motor 10.

A multicolored ribbon cassette 1 that is detachably attached to a mounting table 5
3 ribbon 14 has 4 zones 15, 16, 17, 18
are color-coded.

Therefore, in spiral 7, each zone 15, 16, 17, 18
The mounting table 5 is switched to the position a so that it faces the printing unit 4.
Control unit 19.20, 21.2 for positioning b, Q, d
2 is formed. The pitch p of the control unit 19゜20.21.22 is 13 in terms of the number of steps of the step motor 10.
The length 1 of the step and control parts 19, 20, 21.22 is 4
It is a step. Cutouts 23 are formed on the outer peripheries of the gears 1 and 3 so that the gears 11 and 12 are disengaged when the mounting table 5 reaches the home position a. Further, the carrier 1 is provided with a plate spring 25 that elastically abuts on a protrusion 24 formed on the outer periphery of the cam 8 when the mounting table 5 is located at the home position.

Further, the carrier 1 is provided with an adjustment mechanism 26 for displacing the cam 8 in the axial direction. This adjustment mechanism 26 is the seventh
As shown in the figure, a cylinder 27 that slidably holds the cam 8
The adjustment spiral 28 is screwed onto the cylinder 27 and presses the cam 8, and the spring 29 biases the adjustment spiral 28 in the axial direction.

In such a configuration, when the step motor 10 is driven, the cam 8 rotates and the mounting table 5 is rotated in the vertical direction. When the pins 9 of the mounting table 5 are sequentially lifted by the control unit 19°, 20, 21, and 22, the mounting table 5 is displaced as indicated by a, b, a, and d in Fig. 4, and the color is switched. .

When the pin 9 is supported by the control unit 22, the mounting table 5 is located at the switching position 11d, and from this state, one pitch p between the control units is
When the step motor 10 is driven to rotate the cam 8 counterclockwise in 39 steps, which is three times the number of steps, the third
As shown in the figure, the notch 23 faces the gear 11 and the gear 11.
12 is disengaged, and at this time, the rotational inertia of the cam 8 is also lost due to the plate spring 25, and even if the teeth of the gears 11 and 12 slightly contact each other, the cam 8 will move 1 step per step of the step motor 10.
In this state, the pin 9 is supported by the control unit 19 and the mounting table 5 is at the home position. is positioned. Therefore, no matter which switching position the mounting table 5 is at, by rotating the step motor 10 in one direction by 39 steps or more with a designated phase, the home position adjustment of the mounting table 5 and the phase alignment of the step motor 10 can be performed. Can be easily done at once.

It should be noted that since the control units 19.20, 21.22 have a length corresponding to a plurality of steps in terms of the number of steps of the step motor 10, each switching position is accurate.

Further, by turning the adjustment spiral 26 and slightly moving the cam 8 in the axial direction, the home position a of the mounting table 5 can be determined even more accurately.

Effects of the Invention Since the present invention is configured as described above, the step motor rotates the cam to displace the mounting base, and the ribbon of the multicolor ribbon cassette is made to face any color zone to the printing section. Regardless of the position, as long as the step motor is driven, it will be displaced and reach the home position, and at this time the gears can be disengaged. By holding and driving the device, it is possible to easily determine the home position of the mounting table, and at the same time, it is possible to easily match the step motor.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a side view, FIG. 2 is a plan view, FIG. 3 is an enlarged plan view showing the connection structure between the step motor and the cam, and FIG. 5 is a plan view showing the ribbon, FIG. 6 is a developed view of the cam spiral, and FIG. 7 is an enlarged vertical sectional side view showing the adjustment mechanism.

Claims (1)

[Claims] A mounting table that holds a multicolored ribbon cassette having ribbons color-coded into a plurality of zones is provided so as to be freely displaceable in a direction perpendicular to the moving direction of the carrier, and a cam for displacing the mounting table is a step motor that can freely rotate in forward and reverse directions. A plurality of control parts are formed on the cam and connected to each other on the carrier to position the mounting base at each switching position so that each of the zones faces the printing part, and the length of the control parts is set in the step. The length is set to correspond to a plurality of steps of the motor, and at least two gears are provided in the power transmission path from the step motor to the cam, and at least one of these gears has teeth at the home position of the mounting base. A ribbon position switching device characterized in that a notch is formed to disengage the ribbon.