JPH0573592B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a serial printer capable of performing multicolor printing by shifting an ink ribbon.

[Prior art]

Conventional serial printers that perform multicolor printing include models that have a dedicated printing section for each color, each of which prints independently to achieve multicolor printing, and models that have ink ribbons that are divided into multiple colors. There is a type that prints all colors on one printing section by shifting its position.

The former type, which is equipped with a dedicated printing section, requires the development of a dedicated print head, and when using the print heads used in general serial printers, the carriage must be equipped with print heads equal to the number of colors. As a result, the printing section becomes very large and heavy, which is extremely disadvantageous in reducing the size and weight of the printer.

As for the latter method of shifting the ink ribbon, there are various methods as follows. In particular, for ink ribbon cartridges mounted on a carriage, the first method is to move the ink ribbon cartridge in the vertical direction, the second method is to move the ink ribbon cartridge horizontally, and the third method is to have a rotating shaft at the side end of the cartridge. A method in which the ink ribbon cartridge is rotated in a direction perpendicular to the direction in which the cartridge runs.
Fourthly, there is a method that has a rotating shaft at the rear end of the cartridge and rotates the front part of the ink ribbon cartridge in the vertical direction.In particular, this fourth method is currently often used as a means for switching between red and black ink ribbons. There is.

However, either method requires a dedicated drive source for moving the ink ribbon cartridge, and in that case, if the drive source is provided outside the carriage, a means for transmitting power from it to the carriage is required. Further, if there is a drive source within the carriage, it is possible to directly transmit power from that source, but conventional drive sources have drawbacks such as increasing the size of the carriage and requiring additional wiring.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and its object is to realize a small and lightweight serial printer equipped with a motor for ribbon shifting and the like.

[Summary of the invention]

In order to achieve this object, the present invention provides a serial printer having a printing head in which a plurality of electromagnets are arranged in a circular pattern, in which the polarity of the surface facing the electromagnets is divided and magnetized so that they are alternately N and S. A rotor having a permanent magnet is rotatably attached to the back of the printing head, and the rotor and the electromagnet constitute a motor, and the power of this motor is used for shifting the ink ribbon and feeding the paper. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a perspective view of a carriage frame equipped with an ink ribbon shift mechanism, and Fig. 2 is an exploded perspective view. In the figure, 1 is a print head, and 2 forms a motor paired with this print head 1. A rotor, 3 an idle gear, 4 a ribbon shift drive gear connected via the rotor 2 and the idle gear 3, 5 an ink ribbon cassette, 6 a multicolor ink ribbon, and 7 a cassette receiving case for holding the ink ribbon cassette 5. It is integrated with a gear 8 that meshes with the drive gear 4 and moves the cassette receiving case 7 up and down. Reference numeral 7a represents a rotational fulcrum of the cassette receiving case 7, and reference numeral 9 represents a carriage frame, which moves horizontally along guides 10 and 11. 12 is a synchronized belt for moving this carriage frame 9; 13 is a ribbon drive gear; 14, 15, and 16 are meshed with the racks provided on the guide 10 and rotated by the movement of the carriage frame 9 to form ribbon drive gears; 13 is a rotating gear, and 17 is a cover that holds these gears.Next, the motor constructed within the print head 1 will be explained according to the drawings.

Fig. 3 is a sectional view of the motor, Fig. 4 is a plan view showing the arrangement of partially magnetized permanent magnets and the core, and Fig. 5 is a side development view of the permanent magnets and core. , 18 is the core, 19 is the core 18
A plurality of electromagnets consisting of the core 18 and the drive coil 19 are attached to the print head 1.
They are arranged in a circular pattern on the back side of the . 20 is a board for connecting each of the electromagnets to a drive circuit; 21 is a Hall element attached to this board for detecting the rotation speed of the rotor 2; 22 is a permanent magnet forming the rotor 2; The surface of the permanent magnet 20 facing the electromagnet is divided and magnetized so that the polarity is alternately N and S. The bearing section of the rotor 2 having this permanent magnet 20 is connected to the bearing 23 of the printing head 1 on one side and the bearing 23 of the carriage frame 9 on the other side.
The distance between the permanent magnet 22 and the core 18 is the same as the shoulder 2a of the rotor 2.
is kept in constant contact with one end surface of the frame 25 of the print head 1.

Next, the operation of the above configuration will be explained.

First, the operation of the motor will be described.

FIG. 4 shows a state where the permanent magnet 22 of the rotor 2 is partially magnetized and stands still facing the core 18 at the boundary of opposing polarity, and FIG. 5 shows the permanent magnet 22, the core 18, This is a view of the drive coil 19 unfolded from the side. In order to rotate _the rotor 2 in the direction _{of arrow} R in _FIG .
Drive coils 19 1 , 19 ₃ , 19 _{5 ,} 1 so that 8 ₉ , 18 ₁₁ , 18 ₁₃ , 18 ₁₅ become N poles.
When power is applied to 9 ₇ , rotor 2 starts rotating,
When the boundary reaches the magnetic pole of the permanent magnet 22 near the center of the permanent magnet facing surface 18 ₉ , 18 ₁₁ , 18 ₁₃ , 18 ₁₅ of each of the cores 18 ₁ , 18 ₃ , 18 ₅ , 18 ₇ , the energization is stopped. . Then, each permanent magnet 22 continues to rotate in the direction of the next core in the rotational direction by receiving rotational torque. Further, by energizing each of the cores 18 ₁ , 18 ₃ , 18 ₅ , and 18 ₇ again near the boundaries of each of the permanent magnets 22, the rotor 2 continues to rotate stably in the direction of arrow R, and this rotation The number of rotations is counted by the Hall element 21, and when a predetermined number of rotations is reached, the energization is stopped.

Next, in order to rotate the rotor 2 in the direction of the arrow L, the permanent magnet facing surfaces 18 ₁₀ , 18 ₁₂ , 18 ₁₄ , 18 ₁₆ of the cores ₂ , 18 ₄ , 18 ₆ , 18 ₈ are turned to S poles, respectively. Drive coils 19 ₂ , 19 ₄ , 19
₆ and 19 ₈ can be rotated in the same manner.

Note that in order to stop the rotation of the rotor 2, the drive coils used to drive the rotor 2 are short-circuited, or the drive coils that are not used to drive the rotor 2 are energized in the opposite direction to the drive direction. The rotor 2 can be braked by this.

Further, the number of drive coils used when driving the rotor 2 may be arbitrarily determined depending on the characteristics of the motor and drive conditions.

Next, the overall operation will be explained.

When a ribbon shift is to be carried out, the carriage frame 9 is positioned on the left or right side of the travel range away from the print range, and the print head 1 starts to be driven as a motor there.

When the rotor 2 rotates, power is transmitted to the gear 8 which is integrated with the cassette receiving case 7 through the gears 3 and 4 connected thereto, and the cassette receiving case 7 is rotated relative to the carriage frame 9 around the rotation fulcrum 7a. perform rotational motion. At the same time, the ink ribbon cassette 5 also rotates and moves vertically relative to the print head 1 attached to the carriage frame 9. As a result, since the ink ribbon 6 is divided into multiple colors in the width direction, when the ink ribbon 6 is moved vertically by a certain amount, the color of the ink ribbon corresponding to the tip of the print head changes.

After the drive coil 19 is energized to control the rotation of the rotor 2 and the ink ribbon 6 is changed to a desired color, the carriage frame starts moving again and performs normal printing. At this time, the condition of the excitation current to the coil of the print head 1 is that the capacity is small compared to that when used as a motor, and it is irregular, so the rotor 2 does not move during the printing operation and is kept at the desired position. It remains retained.

Furthermore, even if the ink ribbon 6 is not multicolored, by shifting the ribbon every certain number of prints, it is possible to print using the entire width of the ink ribbon 6, which extends the life of the ink ribbon 6. It is possible to reduce running costs.

In the above embodiment, it is thought that the drive current during printing does not rotate due to loads such as the frictional force of the gear and the weight of the ink ribbon cassette, but it depends on the structure of the print head 1 and the magnitude of the load. There is a risk that the blade may rotate during printing. In such a case, the frictional force of the rotor 2 or gear system may be increased, or a detent force may be applied to the ink ribbon cassette 5. For example, as shown in FIG. 6, a plate material 26 with corrugated irregularities is formed on the carriage frame 9, and a protrusion 5a is formed on the side surface of the ink ribbon cassette 5, and the detent mechanism is formed by the plate material 26 and the protrusion 5a. All you have to do is configure.

In addition, by setting the current value when operating as a motor to 2 to 3 times the current value when operating as print head 1, the setting range of friction force and detent force is increased and operation is ensured. can do. Furthermore, since the time it is operated as a motor is short, the drive transistors and coils do not generate heat and burn out.

Furthermore, the present invention can be used for purposes other than shifting the ink ribbon 6 as described above. For example, a gear may be attached to the rotating shaft of the rotor 2, and another gear may be provided that meshes with this gear outside the printing area. The paper may be fed by rotating another gear.

〔Effect of the invention〕

According to the present invention described in detail above, the motor is configured using the electromagnet of the print head, and the power is used as a driving source for, for example, shifting the ink ribbon or feeding the paper, so that the ink ribbon can be printed with a small and simple configuration. It has the advantage that it is lightweight and requires only the print head to be wired to the carriage frame, which is the same as in the past, resulting in faster and more accurate printing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main part of the ink ribbon shift mechanism of the present invention, FIG. 2 is an exploded perspective view of the same, and FIG.
The figure is a sectional view of the motor part, Figure 4 is a plan view showing the partially magnetized permanent magnet and core in a stationary state, and Figure 5 is a cross-sectional view of the motor part.
This figure is a developed side view of the state of the permanent magnet and core shown in FIG. 4, and FIG. 6 is a partial side view showing another embodiment of the carriage frame and ink ribbon cassette. 1...Printing head, 2...Rotor, 5...Ink ribbon cassette, 6...Multicolor ink ribbon, 9
...Carriage frame, 18...Core, 19...
...Drive coil.

Claims (1)

[Scope of Claims] 1. A serial printer having a printing head in which a plurality of electromagnets are arranged in a circle, which includes permanent magnets that are divided and magnetized so that the polarity of the surface facing the electromagnets is alternately N and S. A serial printer characterized in that a rotor is rotatably attached to the back of the print head, and a motor is constituted by the rotor and the electromagnet.