JPS625068B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in type belt type printing devices.

Figure 1 is a schematic plan view of a type belt type printing device.
Figure 2 is a side view of the same main parts, in which 1 is a drive pulley, 2 is an idler pulley, 3 is a type belt stretched around these pulleys, 4 is a printing hammer, and 5
6 is a printing magnet, 6 is a platen, and 7 is a ribbon cassette. The type belt 3 has a large number of type characters 8 on its surface at equal intervals, and is driven by a drive pulley 1 which is rotated in the direction of the arrow by a drive motor 9 via a belt 10, and travels along the platen 6. An endless ink ribbon 11 fed out from the ribbon cassette 7 runs along the surface of the type belt 3 on the platen 6, is fed into the ribbon cassette 7, and circulates. The paper 12 is transported by the paper feed tractor 13 and positioned at a printing position facing the platen 6. Printing on this paper 12 is performed as follows.

That is, when the printing magnet 5 facing a predetermined printing hammer 4 is activated at a predetermined time, the printing hammer 4 is attracted to the printing magnet 5 and swings in the counterclockwise direction shown by the arrow in FIG. is pressed against a predetermined type 8 on the type belt 3 via the ink ribbon 11 to print. When one line of printing is completed, the paper 12 is transported by the line pitch by the paper feed tractor 13, and printing is performed on the next line. Note that 14 is a ribbon shield.

Details of the idler pulley 2 support mechanism in this printing device are shown in FIGS. 3 and 4. As shown in the figure, the idler pulley 2 is attached to the bracket 15.
The bracket 15 is rotatably supported via a bearing 17 on a shaft 16 fixed to a shaft 16, and the bracket 15 is rotatably supported on a base 18 of the device via a pin 19 in the directions of arrows A and A' in FIG. The bracket 15 is urged in the direction of arrow A by a spring 20 provided between the bracket 15 and the base 18, and the type belt 3 is given tension by this spring 20.

In a printing device having such a configuration and operation, as shown in FIGS. 3 and 4, a guide roller 2 for guiding the type belt is provided on the type belt feeding side of each pulley.
1 is provided. In this way, guide roller 2
The reason why 1 is provided only on the type belt feeding side of each pulley and not on the type belt feeding side is because if it is provided on the type belt feeding side, the pressure applied to the guide roller due to deviation of the type belt will be too large, so the guide roller, This is because the life of the type belt becomes extremely short.

Conventionally, this guide roller 21 is supported by a base 18 via a support fitting 22, as illustrated in detail in FIG. 4 on the idler pulley side.

By the way, in the above-described idler pulley support mechanism, there is some play between the pin 19, the bracket 15, and the base 18, so that the idler pulley 2 tilts due to its own weight as shown by the chain line in FIG. However, the type belt 3 that tries to run along the crown of the pulley will end up on the lower side of the figure on the feeding side of the idler pulley 2, causing a misalignment of the print in the print section.
This problem could not be solved by the guide roller 21 supported by the guide roller 21 .

The present invention is intended to solve the above-mentioned problems,
It is an object of the present invention to provide a printing device that can prevent deterioration in print quality by correcting changes in the running position of a type belt due to the inclination of an idler pulley.

Next, an embodiment of the present invention will be described with reference to FIG. In the figure, members having the same structure as the conventional one are represented by the same symbols, and 31 is a bracket and 32 is a guide roller.

In the conventional example shown in FIGS. 4 and 5,
The guide roller 21 for guiding the type belt on the feeding side of the idler pulley 2 was supported by the base 18 via a support fitting 22, but in the embodiment of the present invention shown in FIG. The difference is that it is configured to be rotatably supported at the end of the . Note that the other configurations are the same as those of the conventional example shown in FIGS. 4 and 5, so detailed explanation thereof will be omitted.

In FIG. 6, the guide roller 32 is connected to a shaft fulcrum at which the idler pulley 2 is supported by a shaft 16 with respect to a shaft fulcrum consisting of a pin 19 rotatably supported by a base 18'. It is rotatably supported by the end of the bracket 31 on the opposite side, and its position is below the retraction point, which is the point where the type belt 3 first contacts the idler pulley 2 on the retraction side. With this, the guide roller 32 guides the side edge of the type belt 3, so that the positional relationship of the type belt 3 with respect to the idler pulley 2 can be regulated even while the type belt 3 is running. It is configured.

Bracket 31 includes pin 19 and base 18',
Since there is play in the fitting portion with the bracket 31, the idler pulley 2 tilts due to its own weight, and accordingly, the idler pulley 2 also tilts as shown by the chain line. When the idler pulley 2 is tilted in this manner, the type belt 3, which attempts to run along the crown of the pulley, is lowered by β at the delivery portion of the idler pulley 2. This β is expressed by the following formula.

β=D=・θ...(1) Here, D=Outside diameter θ of idler pulley 2=Inclination angle of idler pulley 2 On the other hand, in the present invention, the guide roller 32 is directly supported by the bracket 31 as described above. Therefore, when the idler pulley 2 and bracket 31 are tilted, the guide roller 32 moves upward, and the type belt 3, which is supported in contact with the guide roller 32 on the feeding side of the idler pulley 2, is lifted by the guide roller 32. The amount α is expressed by the following formula.

α=a・θ...(2) Here, a=type belt 3 and bracket 31
Distance from the point of contact with the base 18' when tilting (the fulcrum of tilting).

Therefore, the amount of descent δ of the type belt 3 is as follows.

δ=D・θ−aθ=(D−a)・θ……(3) That is, by appropriately selecting D and a, the change in the running position of the type belt 3 in the printing section can be kept within the desired range. It is possible to keep it within.

As described above, according to the present invention, it is possible to correct the change in the traveling position of the type belt in the printing section and prevent the print quality from deteriorating.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an overview of the type belt type printing device, Figure 2 is a side view of the main parts, Figure 3 is an explanatory diagram of the guide roller arrangement, and Figure 4 is the conventional type belt feeding side of the idler pulley. Figure 5 is a guide roller support guide diagram, Figure 5 is an illustration of the idler pulley inclination, Figure 6 is a guide roller support diagram.
The figure is a front view showing the main parts of an embodiment of the printing device according to the present invention, in which 1 is a drive pulley, 2 is an idler pulley, 3 is a type belt, 18' is a base,
19 is a pin, 31 is a bracket, and 32 is a guide roller.

Claims (1)

[Claims] 1 Comprising a drive pulley, an idler pulley, and a type belt stretched around these pulleys,
The idler pulley is rotatably supported by a bracket that is rotatably provided around an axis parallel to the axis of the drive pulley, and the bracket is attached to rotate in a direction away from the drive pulley. In a printing device in which tension is applied to the type belt by a biasing means for applying tension, the bracket rotates a guide roller that guides a side end of the type belt on the type belt feeding side of the idler pulley. The side end of the type belt is supported by providing it at the lower part of the winding point of the type belt with respect to the idler pulley at the end of the bracket on the opposite side of the shaft fulcrum of the idler pulley via the supported shaft fulcrum. A printing device featuring: