JPH068588A - Serial printer - Google Patents

Abstract

PURPOSE:To provide a driving force transmission mechanism by which a shift motor can be efficiently used and the function of a serial printer can be en hanced at the same time. CONSTITUTION:The driving force of a shift motor 20 is transmitted to a shift device 19 revolving a ribbon cassette 7 in a vertical direction by altering the rotary direction of the gear 21 and pulley 22 fixed to the output shaft of the shift motor 20. By this constitution, the rate of operation of the shift motor can be enhanced to the same degree as that of a paper feed motor or a carriage motor and the shift motor can be efficiently used and the function of a serial printer can be enhanced at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer. More specifically, it relates to a driving force transmission mechanism.

[0002]

2. Description of the Related Art A typical prior art relating to a driving force transmission mechanism of a serial printer equipped with a ribbon shift device is disclosed in Japanese Patent Application Laid-Open No. 63-7967.

FIG. 4 is a plan view showing the main part of a serial printer using this conventional driving force transmission mechanism.

First, the structure will be described with reference to FIG.
In FIG. 1, 1 is an impact dot head for printing on a print sheet (not shown), 2 and 3 are side frames, 4
Reference numerals 5 and 5 are guide shafts provided between the side frames 2 and 3, 6 is a carriage which is guided by the guide shafts 4 and 5 to reciprocate, and the carriage 6 has a ribbon cassette 7 for accommodating an ink ribbon (not shown). It has bearings 8 and 9 for supporting, and rotatably supports the shafts 10 and 11 on both sides of the ribbon cassette 7.

Reference numeral 12 denotes a shift arm which is rotatably attached to the center of the carriage 6 with a pin 13 as a fulcrum.
One end 14 is in contact with the bottom surface of the ribbon cassette 7, and the other end 29 has a roller 30 attached thereto.

Reference numeral 31 denotes a cam shaft, which is rotatably attached to the auxiliary frames 32 and 33. 34, 3
Reference numeral 5 is a shift cam, and 36 is a gear, which is fixed to the cam shaft 31. A shift plate 37 extends between the auxiliary frames 32 and 33 and is in contact with the roller 30 of the shift arm 12.

When the carriage 6 reciprocates for printing, the roller 30 moves together with the carriage 6 while rotating along the shift plate 37 set by the shift cams 34 and 35.

Reference numeral 20 denotes a shift motor, reference numeral 38 denotes a worm gear attached to the rotary shaft of the shift motor 20, which meshes with the gear 36. The rotation of the shift motor 20 is transmitted to the rotation of the cam shaft 31. .

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

When the shift motor 20 rotates, the cam shaft 31 rotates via the worm gear 38 and the gear 36, and the shift cam 3 fixedly mounted on the cam shaft 31.
4, 35 rotate.

[0011]

However, the driving force transmission mechanism of the serial printer using such a conventional technique performs the ribbon shift by driving the shift motor 20. However, the ribbon shift is not frequently performed during the printing operation unless the color printing is performed. Therefore, the operating rate of the shift motor 20 is much lower than that of other paper feed motors and carriage motors, and is used efficiently. I can't say. Further, since the ribbon cassette 7 is rotated in the vertical direction to perform the ribbon shift, there is a problem that the shift motor 20 cannot be replaced with an inexpensive one having a small torque even though the operation rate is low.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a ribbon shift device for rotating the ribbon cassette up and down by a drive force of a shift motor, and an impact dot head. Another object of the present invention is to provide a driving force transmission mechanism that can be efficiently transmitted to a cooling device for cooling the shift motor and can efficiently use the shift motor and at the same time enhance the function of the serial printer.

[0013]

In order to solve the above-mentioned problems, a serial printer of the present invention is provided with a carriage movable along a guide shaft arranged parallel to a printing surface, and mounted on the carriage. An impact dot head that prints on a print sheet based on a selection operation of a plurality of print pins, and a ribbon cassette that is mounted on the carriage and is vertically rotatable around a bearing provided on the carriage. In the serial printer having the above, a ribbon shift device driven by a shift motor to rotate the ribbon cassette in the up-down direction and a cooling device driven by the shift motor to cool the impact dot head are provided. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view showing an essential part of a serial printer using the driving force transmission mechanism of the present invention, FIG. 2 is a side view showing an essential part of the driving force transmission mechanism of FIG. 1, and FIG. 3 is a ribbon shift device of FIG. It is a side view which shows the principal part.

First, the structure will be described. In FIG. 1, 1 is an impact dot head for printing on a print sheet (not shown), 2 and 3 are side frames, 4 and 5 are guide shafts provided between the side frames 2 and 3, 6 is a guide shaft 4, 5 is a carriage that is reciprocated by being guided by the carriage 5. The carriage 6 has bearing portions 8 and 9 for supporting a ribbon cassette 7 that stores an ink ribbon (not shown), and a shaft portion 10 on both sides of the ribbon cassette 7. , 11 are rotatably supported.

Reference numeral 12 denotes a shift arm, which is attached to the center of the carriage 6 so as to be rotatable around a pin 13 as a fulcrum.
One end 14 is in contact with the bottom surface of the ribbon cassette 7, and the other end 15 is in contact with the shift cam 16.

Reference numeral 17 denotes the entire ribbon shift device (hereinafter, simply referred to as a shift device).
It comprises a guide shaft 4 rotatably attached to the side frames 2 and 3, and a shift cam 16 attached movably in the axial direction of the guide shaft 4. The shift cam 16 is guided by the guide shafts 4 and 5 to reciprocate. It moves together with the carriage 6. A key groove 18 is formed on the guide shaft 4.

A shift device drive gear 19 is fixed to one end of the guide shaft 4. 20 is a shift motor, 21
Gears and pulleys 22 and 22 are fixed to the output shaft of the shift motor 20, and the shift motor 20 is screwed and fixed to an auxiliary frame (not shown).

The shaft 23 is rotatably supported by the side frame 3, a transmission gear 24 is fixed to the shaft 23, and a one-way clutch gear 25 is attached thereto. The transmission gear 24 meshes with the gear 21, and the one-way clutch gear 25 meshes with the shift device drive gear 19.

The shaft 26 is rotatably supported by an auxiliary frame (not shown), and a pulley 27 is fixed to the shaft 26. A cooling device drive gear (not shown) is fixed to one end of the shaft 26. By this cooling device drive gear, the driving force is transmitted to a cooling device (not shown) that cools the impact dot head 1.

A belt 28 is stretched between the pulley 22 and the pulley 27.

Next, the operation of this embodiment configured as described above will be described.

The gear 21 and the pulley 22 which are usually fixed to the output shaft of the shift motor 20 rotate in the direction of arrow (a).
The rotation of the pulley 22 is transmitted to the pulley 27 via the belt 28, and the rotation of the pulley 27 is transmitted to the shaft 26 to rotate the cooling device driving gear (not shown) and the driving force to the cooling device (not shown). It The rotation of the gear 21 is transmitted to the transmission gear 24, and the rotation of the transmission gear 24 is transmitted to the shaft 23. At this time, the one-way clutch gear 25 idles, and the drive force is not transmitted to the shift device drive gear 19.

Next, when a drive command for the shift device 17 is issued from a control circuit (not shown), the gear 21 and the pulley 22 fixed to the output shaft of the shift motor 20 are issued by the command.
Rotates in the direction of arrow (b). The rotation of the gear 21 is transmitted to the transmission gear 24, and the rotation of the transmission gear 24 is transmitted to the shaft 23. At this time, the one-way clutch gear 25 transmits the driving force to the shift device drive gear 19 without idling.
When the shift device drive gear 19 rotates, the guide shaft 4 rotates, and the shift cam 16 also rotates via the key groove 18 of the guide shaft 4.

As described above, by changing the rotation directions of the gear 21 and the pulley 22 fixed to the output shaft of the shift motor 20, the driving force of the shift motor 20 is shifted to vertically rotate the ribbon cassette 7. It is adapted for transmission to the device 19.

[0026]

As described above, in the present invention,
Since the drive force of the shift motor is transmitted to the ribbon shift device that rotates the ribbon cassette in the vertical direction and the cooling device that cools the impact dot head, the operating rate of the shift motor is determined by the paper feed motor and the carriage. It can be increased to the same level as a motor and can be used efficiently, and at the same time, the function of a serial printer can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a serial printer using a driving force transmission mechanism of the present invention.

FIG. 2 is a side view showing a main part of a driving force transmission mechanism of a serial printer using the driving force transmission mechanism of the present invention.

FIG. 3 is a side view showing a main part of a ribbon shift device of a serial printer using the driving force transmission mechanism of the present invention.

FIG. 4 is a plan view showing a main part of a serial printer using a conventional driving force transmission mechanism.

[Explanation of symbols]

 1 Impact Dot Head 2, 3 Side Frame 4, 5 Guide Shaft 6 Carriage 7 Ribbon Cassette 8, 9 Bearing Part 10, 11 Shaft Part 12 Shift Arm 13 Pins 14, 15, 29 One End 16, 34, 35 Shift Cam 17 Shift Device 18 Key groove 19 Shift device drive gear 20 Shift motor 21, 36 Gear 22, 22 27 Pulley 23, 26 Shaft 24 Transmission gear 25 One-way clutch gear 28 Belt 30 Roller 31 Camshaft 32, 33 Auxiliary frame 37 Shift plate 38 Worm gear

Claims (1)

[Claims] 1. A carriage movable along a guide shaft arranged parallel to a printing surface, and a carriage mounted on the carriage and selecting a plurality of printing pins,
A serial printer having an impact dot head that prints on a printing sheet and a ribbon cassette that is mounted on the carriage and is vertically rotatable about a bearing provided on the carriage. A serial printer comprising: a ribbon shift device that is driven to rotate the ribbon cassette in a vertical direction; and a cooling device that is driven by the shift motor to cool the impact dot head.