JPH0441051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a serial printer that performs printing while feeding a print head laterally.

(Prior Art) As an example of a conventional serial printer, a carriage carrying a print head is connected to a toothed belt or a part of a wire, and this toothed belt or wire is transported by a spacing motor attached to the frame of the printer. Some serial printers print by moving the print head laterally, while other serial printers mesh a cartridge equipped with a print head with a male threaded shaft, and use this male thread shaft with spacing. There is a system in which the print head is rotated by a motor and prints while moving the print head laterally.

However, in such conventional serial printers, the carriage performs the spacing operation by indirectly receiving power from the drive source of the spacing motor via a power transmission means such as a toothed belt or a male screw shaft. There are disadvantages in that the influence of deformation of the transmission means causes fluctuations in the inertia of the carriage, causing variations in printing position, and that the power transmission means complicates the internal structure of the serial printer.

(Object of the Invention) The present invention has been made to solve the above-mentioned disadvantages, and its purpose is to simplify the structure and prevent the printing position from varying by eliminating the above-mentioned power transmission means. Our goal is to provide serial printers.

(Structure of the Invention) In order to achieve this object, the present invention provides a serial printer that prints with the print head while feeding the print head in the lateral direction by transporting the carriage on which the print head is mounted by a spacing motor. In the printer, a spacing motor is integrally attached to a carriage, a bearing part is formed on the rotor of the spacing motor, and a helical shape that engages with the bearing part is formed on a shaft installed along the transport direction of the carriage. The present invention is characterized in that an anti-rotation frame is provided with a groove and is installed parallel to the shaft to engage with the carriage and prevent its rotation.

(Embodiment) Hereinafter, embodiments of the present invention will be explained based on FIGS. 1 to 6. In the figures, 1 is a print head 2.
This is a carriage equipped with an ink ribbon 3 and can move in the horizontal direction, that is, in the printing line direction. 4 is a groove formed at the end of the carriage 1;
Reference numeral 5 denotes a male screw-shaped shaft with a spiral groove 6 carved on its outer periphery, and both ends thereof are fixed to a side frame of a serial printer (not shown). 7 is a spacing motor such as a DC brushless motor,
An annular rotor 8 and a stator 9 are opposed to each other with a constant gap.

The rotor 8 has N and S poles of permanent magnets 10 arranged in a ring shape alternately at equal intervals. Further, the stator 9 has coils 11 arranged in a ring shape in a specific relationship with the arrangement of the permanent magnets 10.

Reference numeral 12 denotes a bearing portion formed at the center of the rotor 7, and a threaded thread 13 that engages with the groove 6 of the shaft 5 is carved on the inner periphery. Reference numeral 14 denotes a bearing, which is provided so that the rotor 8 and stator 9 can freely rotate with respect to each other. A C ring 15 is attached to the bearing portion 12 of the rotor 8, and prevents the rotor 8 from being pulled out from the bearing portion 12.

The spacing motor 7 is integrally attached to the carriage 1 by fixing a stator 9 to one side of the carriage 1, and the shaft 5 is inserted through the shaft 5 through the bearing 12 of the rotor 8. 5 is supported.

Reference numeral 16 denotes a rotation prevention frame that engages with the groove 4 of the carriage 1, and is installed over the entire movement range of the carriage 1 in a casing (not shown). Reference numeral 17 denotes teeth of the rotation prevention frame 16, which are formed at a constant pitch in a portion facing the groove 4 of the carriage 1. 18 is a ribbon drive gear;
It passes through the carriage 1 so as to mesh with the teeth 17. A ribbon drive shaft 19 of the ink ribbon cassette 20 extends below the ink ribbon cassette 20 and is connected to the ribbon drive gear 18.

The ink ribbon cassette 20 is mounted on a cassette holding bracket provided on the carriage 1, but the cassette holding bracket is not directly related to the present invention and is therefore omitted from illustration.

A scale plate 21 is provided with a large number of slits at equal intervals, and is provided parallel to the shaft 5 and the anti-rotation frame 16 over the entire movement range of the carriage 1. Reference numeral 22 denotes a position detector attached to the lower part of the carriage 1. The scale plate 21 is sandwiched between a light emitting element and a light receiving element arranged above and below, and the slit of the scale plate 21 is detected by changes in the amount of light to detect the carriage. Detect the position of 1. 2
3 is a platen, and 24 is printing paper.

Next, the operation of the above structure will be explained. When the printing head 2 is to be subjected to a spacing operation, a current is passed through the coil 11 of the spacing motor 7. At this time, the energization of the coil 11 is sequentially switched from a specific coil 11 to an adjacent coil 11 every time the rotor 8 rotates by a predetermined amount. When current flows through this coil 11, a magnetic field is generated, and the rotor 8 and stator 9 try to rotate relative to each other due to the action of this magnetic field and the permanent magnet 10 of the rotor 8, but the stator 9 is fixed to the carriage 1. Therefore, only the rotor 8 rotates, and the thread 13 of the bearing portion 12 moves along the groove 6 of the shaft 5, so that a propulsive force in the axial direction of the shaft 5 is generated.

At this time, if the groove 6 of the shaft 5 is carved in the shape shown, when the rotor 8 rotates in the direction of arrow A, the rotor 8 advances in the direction of arrow C, and when the rotor 8 rotates in the direction of arrow B, the rotor 8 moves in the direction of arrow C. The rotor 8 is indicated by arrow D
move in the direction.

When the rotor 8 moves as described above, the stator 9 assembled integrally with the rotor 8 and the carriage 1 attached to the stator 9 are moved together along the shaft 5 parallel to the platen 23. As the ink ribbon moves, the ribbon drive gear 18 rotates while meshing with the teeth 17 of the rotation prevention frame 16 to rotate the ribbon drive shaft 19, and a new location on the ink ribbon 3 is pulled out to the printing position.
Further, the printed portion is stored in the ink ribbon cassette 20.

Here, the ink ribbon 3 is fed only when the carriage 1 moves in one direction because the rotation of the ribbon drive gear 18 is transmitted to the ribbon drive roller in the ink ribbon cassette 20 via a one-way clutch (not shown).

It should be noted that the present invention is not limited to the above-mentioned embodiment; for example, the spacing motor 7 may be installed at the right side, upper or lower part of the carriage 1, or the position of the carriage 1 may be detected optically. Alternatively, it may be done magnetically. In this case, if a magnetic detection element such as a Hall element is attached to the carriage 1 so as to face the teeth 17 of the anti-rotation frame 16, and the teeth 17 are magnetized in an arrangement suitable for position detection, the anti-rotation frame 16 Can also be used as a magnetic scale plate.

Alternatively, a part of the frame of the carriage 1 may also be used as a stator, and a coil may be wound around the part of the frame.

Next, an example of the use of the present invention will be described with reference to FIG. 6. In this example of use, three carriages 1 having the above-mentioned configuration are arranged in parallel on the same lateral movement path.

Each of these three cartridges 1 carries a print head 2 and an ink ribbon cartridge 20, and is also provided with a spacing motor 7 on one side thereof. In each of these spacing motors 7, a bearing portion 12 of a rotor 8 is engaged with the same shaft 5, and these rotors 8 are designed to rotate independently.

On the other hand, each carriage 1 is moved laterally independently along the shaft 5 by the rotation of the spacing motor 1, and during this movement, each carriage 1 is guided by a common anti-rotation frame 16. At the same time, in each ink ribbon cartridge 3 on each carriage 1, the ink ribbon 3 is fed by the engagement between the teeth 17 of the rotation prevention frame 16 and each ribbon drive gear 18. Incidentally, the scale plate 21 is commonly used to detect the position of each carriage 1 in order to control the movement of each carriage 1.

Such a serial printer is used for various printing forms because the three carriages 1 can perform spacing operations independently.

For example, if these three carriages 1 are positioned at equal intervals and printed while moving in the same direction at the same high speed, one line can be printed in a short time.

Further, the printing area is divided into three parts, each of the above-mentioned carriages 1 is made to correspond to each of the printing areas, and each of the carriages 1 performs the printing operation while moving freely and independently within each of the above-mentioned printing areas. You can also do it. In this case, the print head 2 mounted on each carriage 1 may be changed for each carriage 1. For example, if a wire dot print head is used as the print head 2, the print head 2 mounted on each carriage 1 may be changed.
It is also possible to print various character patterns and image data by varying the number of wires.

Furthermore, an ink ribbon 3 provided on each carriage 1
By making the printheads different colors and printing different colors using the printing heads 3 mounted on each carriage 1, multicolor printing can be performed.

(Effects of the Invention) As explained above, the present invention includes integrally attaching a spacing motor to a carriage, forming a bearing portion on the rotor of the spacing motor, and
A shaft installed along the transport direction of the carriage is provided with a spiral groove that engages with the bearing part,
In addition, since the anti-rotation frame that engages with the carriage and prevents its rotation is installed parallel to the shaft, the carriage can be directly transferred by the spacing motor integrated with the carriage, which is different from the conventional method. This eliminates the need for a power transmission means, etc. for indirectly transferring the carriage, and also eliminates the need to provide a motor for carriage transfer outside the carriage transfer path. The effect is that high-quality printing can be achieved without variations in printing position.

[Brief explanation of drawings]

Fig. 1 is a left side view showing an embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a sectional view of the spacing motor, and Fig. 4 is a rotor section of the spacing motor shown in Fig. 3. Viewed from the axial direction, Figure 5 is the third
FIG. 6 is a plan view showing an example of the use of the present invention. 1...Carriage, 2...Print head, 5...
Shaft, 7... Spacing motor, 8... Rotor, 12... Bearing section, 16... Rotation prevention frame.

Claims (1)

[Scope of Claims] 1. In a serial printer in which printing is carried out using the printing head while the printing head is being transported in the horizontal direction by transporting the carriage on which the printing head is mounted using the spacing motor, the spacing motor is attached to the carriage. A bearing part is formed on the rotor of the spacing motor, and a helical groove that engages with the bearing part is provided on a shaft installed along the transport direction of the carriage, and the shaft is engaged with the carriage. A serial printer characterized in that a rotation prevention frame for preventing rotation of the shaft is installed parallel to the shaft.