JPS6237732Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a printing device using a petal-shaped printing wheel.

Conventionally, in this type of printing device, a petal-shaped printing wheel is provided so as to be detachable and replaceable, and there are various types of attachment/detachment means. First, as an example, a drive plate that holds the printing wheel is provided on the motor shaft, and the motor is mounted in an up-and-down manner to change the position and direction of the drive plate, thereby changing the setting position and attachment/detachment position of the printing wheel. I'm trying to get selected. In such a device, the motor, motor shaft, drive plate, and other parts must be raised and lowered as one unit, and the set position must be precisely determined, resulting in a complex structure, a large number of parts, and structural stability. It has disadvantages such as low

Next, in another conventional example, a petal-shaped printing wheel is housed in a cassette, a drive plate connected to a motor is provided so as to be able to move forward and backward, and the drive plate is moved by dropping the cassette with the drive plate retracted. There are structures that move us forward. Positioning in the rotational direction is performed by a pin and an engagement hole, and the pin is provided elastically so that it engages when the drive plate is rotated to a certain extent. Therefore, it has the advantage that there are few moving parts during attachment and detachment, and the structure is relatively simple, but the positioning in the rotational direction is determined by a single pin and an engagement hole, and perfect positioning is not possible. Because there is a time variation before this is done and this part will eventually become the driving force transmission part,
It has drawbacks such as lack of stability and durability of power transmission.

In addition, in all of the conventional structures, the motor and the detachable structure for the petal-shaped printing wheel are located in the same direction on the carriage frame, so there is not enough space, and the mounting structure for the ribbon mechanism is quite difficult. Things are getting complicated. Furthermore, an expensive motor with a small advance angle must be used, and if a stepping motor or the like is used, it is difficult to print at high speed due to vibration damping. There is a problem with the decline.

This idea was developed with these points in mind: the petal-shaped printing wheel is extremely easy to attach and detach, its drive is reliable, accurate and high-speed printing can be done even with an inexpensive motor, and the overall layout is It is an object of the present invention to provide a printing device that is simple and easy to attach accessory parts to.

An embodiment of this invention will be explained based on the drawings.
First, a carriage frame 2 is provided which reciprocates along a horizontally provided cylindrical platen 1, and a motor 3 such as a pulse motor is attached to one vertical side of the carriage frame 2. A motor shaft 4 projects from the other side of the carriage frame 2, and a pulley 5 as a drive wheel is attached to the motor shaft 4. A fixed shaft 6 having a tapered tip is attached above the carriage frame 2, and a timing pulley 7 is rotatably attached to the fixed shaft 6. On one end surface of the timing pulley 7 as a driven wheel, protrusions 9 that become the engaging portions 8 are provided at positions dividing the circumference into 25 equal parts. 25 index holes 10 are provided whose positions coincide with the . Also,
A flange 11 is provided on the other surface of the timing pulley 7.
The timing belt teeth 12 are formed with the remaining parts. Timing belt teeth (not shown) are also formed on the small-diameter pulley 5, and a timing belt 13 is stretched between the pulley 5 and the large-diameter timing belt teeth 12 with a predetermined tension. .

A petal-shaped printing ring 14 is then provided.
This petal-shaped printing wheel 14 is provided with a plurality of type legs 16 having type characters 15 formed at the tips thereof. Assume now that the number of printed characters 15 is 100. A center hole 17 is provided at the center of this petal-shaped printing ring 14.
A metal core 18 having a diameter is embedded therein, and 25 recesses 19 that engage with the protrusions 9 of the timing pulley 7 are formed on one side. Further, a single index hole 20 is formed which is positioned so as to overlap the index hole 10.

Next, a support shaft 21 is provided below the carriage frame 2, and this support shaft 21 has a holder 2.
2 is attached so that it can be rotated up and down. This holder 22 is biased by a leaf spring 23 in a direction facing the timing pulley 7. and,
The petal-shaped printing wheel 1 is attached to the lower end of the holder 22.
4 is formed, and a pressure shaft 25 is provided in the middle part. That is, a pressing body 26 is fixed to one end of the pressure shaft 25 and biased to the right by a compression spring 27, and a retaining ring 28 for preventing slippage is provided at the other end.
Further, a hammer 29 is provided above the holder 22.
is installed.

Further, the holder 22 and the carriage frame 2 at positions corresponding to the index holes 10 and 20 are provided with a light emitting diode 30 and a phototransistor 31.

In such a configuration, when attaching or replacing the petal-shaped printing wheel 14, the holder 22 is rotated in a direction away from the timing pulley 7 against the force of the leaf spring 23, as shown in FIG. . As a result, there is a large space in the upper part, and the petal-shaped printing ring 14 is dropped into this part. As a result, the petal-shaped printing wheel 14 is held by the holding edge 24, and then when the holder 22 is brought into a free state, it is pushed by the leaf spring 23 to the state shown in FIG. At this time, the fixed shaft 6 is fitted into the center hole 17 of the petal-shaped printing wheel 4 to achieve center alignment, and the lower end of the petal-shaped printing wheel 14 rises above the holding edge 24, allowing smooth rotation. In addition, the pressure shaft 25
It is pressed between the timing pulley 7 and the timing pulley 7. When the timing pulley 7 is rotated by the drive of the motor 3, the protrusion 9 and the recess 19 immediately engage with each other, and the index hole 20 coincides with one of the index holes 10. As a result, when the petal-shaped printing wheel 14 is positioned between the timing pulley 7 and the position of the motor 3 corresponds to the position of the type 15, printing by the hammer 29 can be performed at an accurate position. The index holes 10 and 20 also ensure the selection of type 15. Further, since the driving force is generated by the engaging portions 8 arranged on the circumference, the driving force is reliably generated in a well-balanced state, and the durability is also high.

Since the rotational speed of the motor 3 is reduced by the diameter ratio of the pulley 5 and the timing pulley 7, it is possible to make the advance angle of the motor 3 considerably larger than the advance angle based on the arrangement spacing of the printed characters 15. This allows the motor 3 itself to be manufactured relatively inexpensively. Furthermore, by tensioning the timing belt 13 with a predetermined tension, it is possible to increase the frictional force in the transmission system from the motor 3 to the timing pulley 7, thereby making the vibration damping of the motor 3 nearly non-existent. It is also possible.

Further, since the motor 3 is provided to protrude from one side of the carriage frame 2, the space on the holder 22 side becomes large, and the installation of the printing ribbon mechanism etc. becomes extremely easy.

In this invention, as mentioned above, the holder is provided so that it can be rotated up and down with respect to the driven vehicle, so there is a large space for installing and removing the petal-shaped printing wheel, and it is easy to operate. Since the petal-shaped printing wheel and the driven wheel are engaged by the engagement part, the driving force transmission is stable and the durability is high.Moreover, the rotation of the motor is controlled by the diameter ratio of the driving wheel and the driven wheel. Since the motor is decelerated, the advance angle of the motor can be increased and a less expensive motor can be used. This allows for high-speed printing and accurate printing alignment. By placing the motor and holder on different sides, there is more space around the holder, which makes it easier to attach accessories and simplifies the overall structure. It is something that you have.

[Brief explanation of drawings]

The drawing shows one embodiment of this invention.
The figure is a longitudinal side view when set, Fig. 2 is a longitudinal side view when opened, Fig. 3 is a longitudinal side view of the timing pulley, Fig. 4 is its front view, and Fig. 5 is its rear view.
FIG. 6 is a longitudinal sectional side view of the petal-shaped printing wheel, and FIG. 7 is a rear view thereof. 2... Carriage frame, 3... Motor, 4
... Motor shaft, 5 ... Pulley drive wheel, 7 ... Timing pulley driven wheel, 8 ... Engagement portion, 14 ... Petal-shaped printing wheel, 22 ... Holder, 25 ... Pressure shaft.

Claims (1)

[Scope of utility model registration request] A motor is attached to one side of the carriage frame, and a driving wheel attached to the motor shaft of the motor and a driven wheel having a larger diameter than the driving wheel are connected and provided on the other side of the carriage frame. A holder is provided with an engaging portion arranged in an arc on the end face of the wheel and a petal-shaped printing wheel to fix the rotational direction of both, and is pivotable up and down between a position facing the driven wheel and a position away from the driven wheel. is attached to the carriage frame, and the holder is provided with a pressure shaft for pressing the petal-shaped printing wheel against the driven wheel.