JPH0529884Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention is applicable to electronic typewriters, daisy printers, etc. equipped with a daisy foil in which a required number of printed characters are arranged radially on the same circle at equal intervals. The present invention relates to a structure for adjusting the position of a daisy wheel in a printing device such that each character accurately stops at a regular printing position.

<Prior art> This type of printing device equipped with a daisy wheel includes a type in which the daisy wheel is attached to the motor shaft of a pulse motor for driving the daisy wheel, in which the daisy wheel is directly connected to the motor, and a type in which the daisy wheel is directly connected to the motor. As shown in the figure, the pinion-side drive gear 3 fixed to the motor shaft 2 of the drive pulse motor 1 and the transmission gear 6 fixed to the rotating shaft 5 of the daisy wheel 4 are meshed to control the rotation of the pulse motor. There is a type of device that transmits data by decelerating the speed based on the reduction ratio of both gears 3 and 4. In this type of device, the predetermined type 7 is placed at the regular printing position exactly facing the hammer (not shown). It requires so-called origin adjustment to adjust the position so that it stops, and conventionally this has been done by the following means. That is, a means for loosening a screw (not shown) that fixes the transmission gear 6 and the rotating shaft 5 and adjusting the mutual positional relationship, and a means for loosening the screw (not shown) that fixes the motor shaft 2 and the drive gear 3. Mainly used are means for adjusting the mutual positional relationship by loosening the bolts, or means for adjusting the fixed position of the pulse motor 1 with respect to the mounting plate by rotating the pulse motor 1.

<Means for solving the problems> However, each of the above-mentioned means has various drawbacks. That is, with the means of and, fine adjustment is difficult because the screws tend to fit into small holes etc. on the rotating shaft 5 or the motor shaft 2. ，
There is a problem in that the accuracy of adjustment decreases due to the clearance between the screws and the screws 2, and furthermore, tapping machining and the like are required, resulting in an increase in costs. On the other hand, according to the method, adjustment is not possible if a general mounting plate 8 as shown in FIG. 4 is used as a means for fixing the pulse motor 1, so as shown in FIG.
A mounting plate 9 having a shape having a and 9b is required. This mounting plate 9 is a custom-made product, which not only increases the cost, but also, as is clear from the comparison with Fig. 4, the larger the shape of the mounting plate 9, the larger the installation space, and the larger the device becomes. There's a problem. Furthermore, when tightening the motor fixing screws inserted through the fixing holes 9a and 9b, the mounting plate 9 rotates slightly, which tends to cause misalignment.Furthermore, when making adjustments after assembly,
Adjustment tools such as screwdrivers are extremely difficult to handle in terms of space, making adjustment difficult.

<Purpose of the invention> The present invention has been developed in view of the above-mentioned conventional problems. To provide a daisy wheel position adjustment structure that can accurately and reliably adjust the position of the daisy wheel relative to the motor shaft of a pulse motor after assembly is completed without making any adjustments.

<Means for Solving the Problems> In order to achieve the above object, the daisy foil position adjustment structure of the present invention has the required number of printed characters 7, 7a to 7d as shown in FIGS. 1 and 2. They are arranged at equal intervals on the same circle, and the rotation of the pulse motor 1 is transmitted at a reduction ratio by a gear mechanism to produce a predetermined type 7.
Daisy foil 4 where a is now selected
In the position adjustment structure of the daisy wheel 4 for finely adjusting the engagement position with respect to the pulse motor 1 so that each of the printed characters 7, 7a to 7d stops at the regular printing position facing the hammer, the pulse motor 1 The number of teeth of the drive gear 10 on the pinion side fixed to the motor shaft 2 of the pulse motor 1 is set to be different from, but close to, the number of steps in one rotation of the pulse motor 1, and the number of teeth of the drive gear 10 on the pinion side fixed to the motor shaft 2 of The number of teeth of the transmission gear 6 that meshes with the drive gear 10 is adjusted according to the reduction ratio determined by the number of steps of the pulse motor 1 and the number of characters of the daisy wheel 4.
The number of characters is different from, but close to, the number of characters, and the rotating shaft 5 of the daisy wheel 4 is held in a state where it can move in a predetermined direction within the range where the transmission gear 6 meshes with and disengages from the drive gear 10. It is characterized by

<Function> When adjusting the position of the daisy wheel 4 with respect to the motor shaft of the pulse motor 1, the daisy wheel 4
The drive gear 10 of the transmission gear 6 is moved by moving the rotation axis of the transmission gear 6.
In this state, the pulse motor 1 is rotated, for example, by one step. Now, if the number of teeth of the drive gear 10 is slightly greater than the number of steps in one rotation of the pulse motor 1, the number of teeth of the drive gear 10
0 rotates by an angle equal to one tooth plus α°. In order to re-engage the transmission gear 6, which remains in the disengaged state, with the drive gear 10, the transmission gear 6 is determined at α° by the number of steps in one revolution of the pulse motor and the number of characters on the daisy wheel 4. It is necessary to rotate the drive gear 10 by a specific angle multiplied by the reduction ratio.

Therefore, in order to bring the transmission gear 6 into mesh with the drive gear 10 again, it is necessary to rotate the transmission gear 6, that is, the daisy wheel 4, by the aforementioned specific angle for each rotation of the pulse motor 1 per step. This means that the positional relationship of the daisy wheel 4 with respect to the motor shaft 2 of the pulse motor 1 in the stopped state is such that the daisy wheel 4 changes in relation to the motor shaft 2 of the pulse motor 1 in the above-mentioned manner every time the pulse motor 1 rotates per step. Daisy wheel 4 is adjusted so that it is advanced in the rotation direction by an angle of
The position of the pulse motor 1 with respect to the motor shaft 2 can be finely adjusted.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2 showing an embodiment of the present invention, the same or equivalent parts as in FIG. 3 are given the same reference numerals. And the driving gear 10
The rotating shaft 5 is supported by bearings 11 and 12 so as to be movable in the axial direction, and is prevented from coming off by an E-ring 13. This configuration differs from that shown in FIG. 3.

In the embodiment structure having such a structure, position adjustment of the daisy wheel 4 with respect to the motor shaft 2 will be explained. In this type of printing device,
As shown in Figure 2, when the power is turned on, the predetermined characters 7
It is necessary to adjust the origin so that a stops accurately at the regular printing position indicated by the dashed line. To adjust the origin, the E-ring 13 must be removed, the rotating shaft 5 must be moved in the direction of the arrow, and the transmission gear 6 must be moved. driving gear 10
After that, the pulse motor 1 is rotated by a predetermined step. For example, if the number of steps of the pulse motor 1 is 24 and the number of characters of the daisy wheel 4 is 96, the reduction ratio i is i
=24/96=1/4. And the drive gear 10
Assuming that the number of teeth is 25, which is different from and similar to the number of steps of the pulse motor 1, which is 24, the number of teeth of the transmission gear 6 is 100 since the reduction ratio i is 1/4.

Therefore, when the pulse motor 1 is rotated by one step with the drive of the transmission gear 6 and the drive gear 10 being released, the rotation angle of the pulse motor 1 and the drive gear 10 is 360°/24= 15°
becomes. Here, since the number of teeth of the drive gear 10 is 25, the angle per tooth of the drive gear 10 is
14.4° (360°/25), and the drive gear 10 rotates by an angle equal to one tooth (14.4°) plus 0.6° (15° - 14.4°) for each step of rotation of the pulse motor 1. Rotate. In order to mesh the transmission gear 6 in the disengaged state with the drive gear 10 again, the transmission gear 6 is adjusted to a reduction ratio (1/4) of 0.6° in the rotational direction when meshing with the drive gear 10. It is necessary to rotate by the angle multiplied by (0.15°). At this time, the daisy wheel 4, which rotates together with the transmission gear 6 through the rotation shaft 5, has a type pitch of 3.75° (360°/96) as shown in FIG. Since it is rotated by an angle of 1/25 of the type pitch (0.15°/3.75°), it is rotated in the direction of rotation. That is, the positional relationship of the daisy wheel 4 with respect to the motor shaft 2 of the pulse motor 1 is such that each time the pulse motor 1 rotates one step, the daisy wheel 6 is rotated by an angle of 1/25 of the type pitch relative to the stopped pulse motor 1. Fine adjustment can be made to the engaged state by rotating in the direction.

Therefore, by rotating the pulse motor 1 in steps until the transmission gear 6 meshes with the drive gear 10 while the predetermined characters 7a of the daisy wheel 4 are located at the regular printing position, the pulse motor 1 of the daisy wheel 4 is rotated. The positional relationship with respect to the motor shaft 2 can be precisely and finely adjusted.

Furthermore, since the mutual mounting positions of the driving gear 10 and the motor shaft 2 and the mutual mounting positions of the transmission gear 6 and the rotating shaft 5 are irrelevant to the adjustment of the positional relationship between the daisy wheel 4 and the motor shaft 2, Each gear 10,
Each shaft 2, which corresponds to 6 by simple fixing means such as press fitting,
5, and furthermore, the pulse motor 1
can be fixed using the common mounting plate shown in FIG.

<Effects of the invention> As explained above, according to the daisy wheel position adjustment structure of the invention, the number of teeth of the drive gear fixed to the motor shaft of the pulse motor can be set to a number different from, but close to, the number of steps of the pulse motor. In addition, the rotating shaft of the daisy wheel is made movable in the direction in which the transmission gear and the driving gear are disengaged, so that the position of the daisy wheel relative to the motor shaft of the pulse motor can be adjusted by rotating the pulse motor in a predetermined step. Can be fine-tuned with extremely high precision,
The adjustment work can also be done easily and quickly. Moreover, since the drive gear and the transmission gear do not take any part in position adjustment, they can be attached to the corresponding shaft by simple fixing means such as press-fitting, and
The pulse motor can also be installed using a general mounting plate, which has the advantage of reducing costs and making the device more compact.

[Brief explanation of drawings]

1 and 2 are a plan view and a cutaway front view of an embodiment of the daisy wheel position adjustment structure of the present invention, respectively, FIG. 3 is a plan view of a conventional structure, and FIG.
5 and 5 are both plan views of the mounting plate of the pulse motor. 1...Pulse motor, 2...Motor shaft, 4...
Daisy wheel, 5...Rotating shaft, 6...Transmission gear, 7,7a-7d...Print, 10...Drive gear.

Claims (1)

[Scope of utility model registration request] The required number of printed letters are arranged at equal intervals on the same circle,
The rotation of the pulse motor is transmitted at a reduction ratio by a gear mechanism, and the daisy wheel, which selects a predetermined type, is connected to the pulse motor so that the daisy wheel stops at the regular printing position where each type is opposed to the hammer. In the daisy wheel position adjustment structure for finely adjusting the alignment position, the number of teeth of the drive gear on the pinion side fixed to the motor shaft of the pulse motor is different from and close to the number of steps in one revolution of the pulse motor. In addition to the number,
The number of teeth of the transmission gear fixed to the rotating shaft of the daisy wheel and meshing with the drive gear is set to the daisy wheel in accordance with the reduction ratio determined by the number of steps of the pulse motor and the number of characters of the daisy wheel. The number of characters is different from, but close to, the number of characters, and the rotating shaft of the daisy wheel is held in a state where it can move in a predetermined direction within a range in which the transmission gear meshes with and disengages from the drive gear. Daisy foil position adjustment structure.