JPH0349883Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a print head drive mechanism for a shuttle printer.

[Prior art] The structure of a conventional shuttle printer is, for example,
As disclosed in Japanese Patent No. 58-96581, the drive signal for the print wire 22a is generated using a timing signal generated from a timing signal generating means provided on the motor shaft. Also, Carrier 21
The transverse feed cam 26 that reciprocates is configured to rotate as a timing pulley 30 rotates, and this timing pulley 30 is driven by a timing belt 32. Then, the timing pulley 30 and the timing belt 3
2 has the following relationship: [number of teeth of timing pulley 30<number of teeth of timing belt 32].

[Problems that the invention attempts to solve] Carrier 21
When the timing pulley 30 and the timing belt 32 are driven, the relationship between the number of teeth of the timing pulley 30 and the number of teeth of the timing belt 32 is as follows. The occlusal state of the teeth will be different. In addition, since there are variations in the shape and pitch of each tooth of the timing belt 32, the carrier 21
The movement of the carrier 21 was slightly different during the first reciprocation and the second reciprocation, and the movement of the carrier 21 in response to the timing signal was slightly different during each reciprocation.

Therefore, dot 25-1 (Fig. 8) printed on the first dot line and dot 25-2 (Fig. 8) printed on the second dot line printed with the same timing signal.
) is not printed directly below the dot 25-1,
The printout ends up being misaligned to either the left or right. For example, when the number 1 is printed, it will be printed as shown in FIG. As can be seen from Figure 9, in the vertical alignment of the dots, the dimension x (x>0)
The center of the dots was misaligned, and the print quality was very poor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a print head drive mechanism for a shuttle printer that can always perform printing with good vertical alignment regardless of component accuracy.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a print head drive mechanism of a shuttle printer with a driven gear provided in the drive mechanism and a drive gear that meshes with the driven gear. The print head drive mechanism has a structure in which there is a relationship such as [number of teeth of driven gear≧number of teeth of drive gear], and the ratio of the number of teeth between the two is an integral multiple.

[Operation] When the print head is driven by the print head drive mechanism configured as described above, the teeth between the driven gear and the driving gear during the reciprocation of the print head to the first dot line and the reciprocation of the second dot line. Since the meshing state of the teeth is the same, the meshing state of the teeth of the driven gear and the driving gear when the same timing signal is generated is exactly the same for both the first dot line and the second dot line.

Therefore, the second dot line printed with the same timing signal as the first dot line is
It is printed directly below the first dot line. The same applies to the following dot lines, and from the above, according to the present mechanism, characters with good vertical alignment can be printed.

[Embodiment] The structure and features of the print head drive mechanism according to the present invention will be explained below with reference to the drawings.

FIG. 1 is a perspective view of a shuttle printer equipped with the print head drive mechanism of the present invention.

Reference numeral 1 denotes a printing head equipped with a plurality of printing means 1-1 that can perform dot printing by energizing a printing solenoid 1-2. 3 is head swing pin 1
-3 and the grooved cam 3-1 that engages with the driven gear 3-2.
and an electric conductor 3-3, and is fixed to a head cam shaft 9.

4 is a driving gear that meshes with the driven gear 3-2, and the relationship between the driven gear 3-2 and the driving gear 4 is [number of teeth of driven gear 3-2≧number of teeth of driving gear 4] and number of teeth. The ratio is an integer multiple. 6 is a motor, 7 is a timing signal generator, and 10 is a paper feed cam fixed to the head cam shaft 9. 11 is a one-way clutch engaged with the paper feed shaft 13; 12 is a paper feed rubber; 2 is a head guide shaft holding the printing head; 8 is printing paper; 5 is a reset detector.

This shuttle printer moves the print head 1 back and forth in the directions of arrows A and U by rotating the head cam 3 in the direction of arrow A, and when the print head 1 is sliding in the direction of arrow A, one dot line is printed. The structure is such that when the print head 1 is sliding in the direction of the arrow C, the paper is fed by one dot pitch.

In a shuttle printer with such a structure, 1
Suppose you print the number . The distribution of dots for the number 1 is as shown in Figure 2.As can be seen from Figure 2, to form the number 1, it is necessary to print 7 dot lines in the paper feed direction, and this This is the print obtained by head 1 making seven reciprocations.

Therefore, let us analyze the process until the number 1 is printed by a shuttle printer equipped with the invented print head drive mechanism.

A signal generated from the reset detector 5 (hereinafter referred to as a reset signal) and a signal generated from the timing signal generator 7 (hereinafter referred to as a timing signal) when printing the dot 20-1 shown in FIG. As shown in the figure. The dots 20-1 can be printed by energizing the printing solenoid 1-2 from the rising edge of the timing signal 31-5 to the rising edge of the timing signal 31-6. The meshing state of the driven gear 3-2 and the driving gear 4 when the timing signal 31-5 rises is as shown in FIG.
are in mesh.

The second dot line after the print head 1 has made one reciprocation and the print paper 8 has been fed by one dot pitch will be explained. The reset signal and timing signal for the second dot line are shown in FIG. The dots 20-2 shown in FIG. 2 can be printed by energizing the print solenoid 1-2 from the rise of the timing signal 32-1 to the rise of the timing signal 32-2. Next, a description will be given of the process up to the printing of the dot 20-3. Driven gear 3- at the rising edge of timing signal 32-5 for printing dot 20-3
2 and the drive gear 4, the relationship between the two is as follows:
[Number of teeth of driven gear 3-2 ≧ Number of teeth of drive gear 4]
Moreover, since the ratio of the number of teeth is an integral multiple, the situation is exactly the same as that shown in FIG. 4. Therefore, the printing means 1- at the rising edge of the timing signal 32-5 and at the rising edge of the timing signal 31-5.
The position of the dot 1 in the thrust direction is the same, and the dot 20-3 printed at the rising edge of the timing signal 32-5 is printed directly below the dot 20-1.

The same process as above is performed for three dot lines and below, and the number 1 printed by the shuttle printer equipped with the print head drive mechanism of the present invention becomes as shown in FIG. As can be seen from FIG. 6, the dot center deviation amount y is y≈0, and the vertical alignment is very good.

Next, FIG. 7 shows a perspective view of another embodiment in which the head cam is driven by multiple stages of deceleration. 3 is a head cam, and 15 is a reduction gear including a drive gear 15-1 that meshes with the driven gear 3-2, and a reduction driven gear 15-2 that meshes with the motor gear 16. The driven gear 3-2 and the driving gear 15
The relationship with -1 is [number of teeth of driven gear 3-2>number of teeth of drive gear], and the ratio of the number of teeth between the two is an integral multiple. In addition, the motor gear 16 and the reduction driven gear 1
It is assumed that the tooth number ratio of 5-2 is not an integral multiple.

If the deceleration rotation is structured like this, the motor gear 16 and the deceleration driven gear 1 for each dot line
The engaged state of 5-2 is no longer the same. Variations in the movement of the reduction gear 15 for each dot line occur due to variations in parts precision, etc., but the drive gear 15-1 and the driven gear 3-2 are decelerating, and the movement of the reduction gear 15 varies. Since this is transmitted to the head cam 3 with a reduction corresponding to the reduction ratio, the variation in the movement of the head cam 3 corresponding to the timing signal at each dot line is minute.

Therefore, the movement of the print head in response to the timing signal is almost the same, and the dot on the second dot line printed with the same timing signal as the dot printed on the first dot line can be printed almost directly below the dot on the first dot line. can.

[Effects of the invention] As described above, according to the invention, the relationship between the driven gear provided in the cam means for reciprocating the printing head and the driving gear that meshes with the driven gear is determined by By setting the ratio of the number of teeth to an integer multiple, the movement of the print head at each dot line can be synchronized with the timing signal. It becomes possible to print numbers and provide high quality printing. The same applies to vertical lines when printing graphics, and vivid figures can be provided, which has a great effect.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a dot configuration diagram with the number 1, Fig. 3 is a time chart of the first dot line, and Fig. 4 is a diagram showing the driven gear 3-2. A front view showing the meshing state with the drive gear 4, FIG. 5 is a time chart of the second dot line, and FIG. 6 is an enlarged view of numbers printed by a shuttle printer equipped with the print head drive mechanism of the present invention. , FIG. 7 is a perspective view showing another embodiment of the present invention, FIG. 8 is an enlarged view showing dot printing on the first and second dot lines of a conventional shuttle printer, and FIG. 9 is a perspective view of a conventional shuttle printer. It is an enlarged view of printed numbers. 1...Printing head, 2...Head guide rod, 3
... head cam, 4 ... drive gear, 5 ... reset signal detector, 6 ... motor, 7 ... timing signal generator.

Claims (1)

[Scope of utility model registration request] In a shuttle printer that performs printing by reciprocating a printing head equipped with a plurality of printing means arranged at predetermined intervals in a thrust direction, a driven gear and a driven gear provided in a cam means for reciprocating the printing head are used. The number of teeth of the driving gear that meshes with the driving gear to rotate the cam means has a relationship such that [number of teeth of the driven gear ≧ number of teeth of the driving gear], and the ratio of the number of teeth is an integral multiple. The print head drive mechanism is characterized by: