JPS606490A - Printing head feed apparatus - Google Patents

Abstract

PURPOSE:To make it possible to set a platen and a printing head in parallel at a predetermined interval without performing adjustment, by changing the interval of the platen shaft and the printing head through a carrier by the eccentric motion of a cylindrical bush based on the revolution of a first guide shaft. CONSTITUTION:When the lever 9 of a first guide shaft 11 is revolved, the shaft 11 and a cylindrical bush 14 are integrally rotated and a carrier 2 moves to a direction for changing the interval of a printing head 1 and a platen 5 by the eccentric motion of the bush 14. Therefore, the parallel state of the guide shaft to the platen 5 is obtained without adjusting said shaft 11 in assembling and the interval between the printing head 1 and the platen 5 becomes constant to the predetermined position of the lever 7 in all regions and interval adjustment becomes unnecessary. In addition, even when no interval accuracy is obtained although the lever 7 is set to a predetermined position, the interval setting is performed if the attachment position of the printing head 1 to the carrier 2 is adjusted and the numbers of adjusting processes can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a print head feeding device for a serial dot printer, and particularly to a mechanism for changing the distance between a print head and a platen.

[Background of the invention]

FIG. 1 shows a schematic plan view of a print head feeding device of a serial dot printer, in which a print head 1 is fixed to a carrier 2, which is parallel to a platen 5 with two guide shafts 6.4 as guides. Move left or right.

The guide shaft 6.4 and the platen 5 are each supported by a frame 6.

Incidentally, in a serial dot printer, printing may be performed simultaneously on not only one sheet of paper but also multiple sheets of paper using carbon dioxide or the like. At this time, there is a considerable difference between the thickness of one sheet of paper and the case of multiple sheets, so in order to maintain print quality, it is necessary to change the distance between print head 1 and platen 5 depending on the thickness of the paper. .

Therefore, the above-mentioned print/rad feed device is provided with a mechanism that allows the distance between the print head 1 and the platen 5 to be changed by rotating the lever 7 attached to one end of the guide shaft 3.

Next, print head 1 in a conventional print head feeding device
The mechanism for changing the distance between the platen 5 and the platen 5 is shown in FIGS.
This will be explained using figures.

2 is a cross-sectional view taken from the direction AA in FIG. 1, and FIG. 3 is a side view taken from the direction BB in FIG. 2. The guide shaft 3 has small diameter portions concentric with the central shaft portion formed at both ends thereof, and eccentric collars 8 are fitted onto each of the small diameter portions.

The guide shaft 3 is fixedly supported by the frame 6 by fitting the eccentric collar 8 into the frame B.

The eccentric collar 8 is eccentric in its outer diameter center axis and the inner diameter center axis into which the small diameter portion of the guide shaft 3 is fitted, and is fixed to the guide shaft 6 with a screw 9.

Further, the lever 7 is attached to the shaft end 2° of the small diameter portion of the guide shaft 3 with a screw 10.

When the lever 7 is rotated, the eccentric casing 8 fixed to the guide shaft portion is rotated relative to the frame 6 on the basis of the outer circumference.

That is, the guide shaft 3 performs the same eccentric movement as the inner circumference of the eccentric collar 8. Therefore, the two eccentric collars 8 at both ends of the guide shaft 3
If #1 is set in the same state, by rotating the lever 7, the guide shaft 3 will move in a direction perpendicular to the platen 5 while maintaining parallel to the platen 5. It moves in a direction that changes the distance from the print head 1.

However, in the conventional print head feeding device having the above-mentioned mechanism, the left and right eccentric collars 8 are separated when assembled, so it is difficult to set the platen 5 and print head 1 parallel to each other while maintaining a predetermined distance. is left and right eccentric collar 8
It is necessary to adjust the guide shafts 3 and 3 separately to make the guide shafts 3 parallel to the platen 5.

If the adjustment of [L eccentric force/--8 is not made.

There was a drawback that parallelism between the platen 5 and the print head 1 and a predetermined distance could not be obtained, and moreover, the adjustment required a considerable number of man-hours.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a print head feeding device that eliminates the drawbacks of the prior art described above and allows the platen and print head to be set parallel to each other with a predetermined distance maintained without adjustment during assembly.

[Summary of the invention]

In order to achieve this object, the print head feeding device of the present invention includes a first guide shaft and a second guide shaft whose both ends are respectively supported by a frame and are parallel to the platen axis, and which fix the print head and a carrier that is movable along the first guide shaft and whose rotation is restrained by having one end slidably engaged with the second guide shaft; and a carrier that is inserted into the carrier through the first guide shaft. and a cylindrical pusher fitted inside, the center axis of the outer diameter of the cylindrical pusher being eccentric with respect to the center axis of the first guide shaft, and the cylindrical pusher being rotatable with respect to the carrier. However, the carrier is restrained in the axial direction, and slides with respect to the first guide shaft, but rotation is restrained, and when the first guide shaft is rotated, the eccentric movement of the cylindrical bushing causes the carrier to It is characterized in that it is configured to move in a direction that changes the distance between the platen and the print head.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 is a cross-sectional plan view of a mechanism portion that changes the distance between the print head and the platen in the print head feeding device of the present invention, and FIG. 5 is a side view as viewed from the direction CC in FIG. 4.

In the figure, the frame 6 includes a first guide shaft 11 and a second guide shaft for guiding the carrier 2 to which the print head 1 is fixed.
A guide shaft 12 is provided.

The first guide shaft 11 and the second guide shaft 12 have small diameter parts concentric with the central shaft part formed at both ends thereof, and are fixed and supported by the frame frame 6 by fitting the small diameter parts into the frame 6, respectively. It is also kept parallel to the platen (not shown).

Furthermore, a lever 7 is attached to one shaft end of the first guide shaft 11 on the outside of the frame 6 via a bolt 10 .

The carrier 2 is provided so as to be movable along the first guide shaft 11, and its rotation is restrained by slidably engaging the second guide shaft 12 in a groove 13 formed at one end.

The groove 13 restrains the vertical movement of the carrier 2,
Moreover, it has a shape that allows movement toward the platen side.

Furthermore, a cylindrical bushing 14 through which the first guide shaft 11 is inserted is fitted inside the carrier 2 . The center axis of the outer diameter of the cylindrical pusher 14 is aligned with the first guide shaft 11.
The central axis of the outer diameter is eccentric with respect to the central axis of the first guide shaft 11 so that it is located above the central axis of the first guide shaft 11.

Further, the cylindrical pusher 14 is free to rotate relative to the carrier 2, but its movement in the υ-axis direction is restrained by a stopper 16 attached to the side end of the carrier 2 via a bolt 15 20.

Further, the cylindrical bush 14 slides in the axial direction with respect to the first guide shaft 11, but rotates due to the engagement of the key groove provided on the inner surface of the cylindrical bush 14 with the key 17 provided on the first guide shaft 11. is being restrained.

In addition, in FIG. 5, 18 is the print head 1 on the carrier 2.
The bolts used to secure the are shown.

Next, the operation of the present invention will be explained.

When the lever 7 attached to the first guide shaft 11 is rotated, the first guide shaft 11 and the cylindrical bushing 14 rotate together with the central axis of the first guide shaft 11 as the rotation center. The eccentric movement of the pusher 14 causes the carrier 2 to move in the direction of the arrow in FIG. 5, that is, in a direction that changes the distance between the print head 1 and the platen.

Therefore, in the present invention, it is possible to create a state parallel to the platen without adjusting the first guide shaft 11 during assembly.

In addition, since the distance between the print head 1 and the platen is constant over the entire area for a given lever position, there is no need for the conventional distance adjustment, that is, no assembly adjustment is required.

Furthermore, even if the spacing accuracy between the print head 1 and the platen is high relative to the machining accuracy of the lever 7, and even if the lever 7 is set at a predetermined position, the spacing accuracy cannot be obtained, the carrier 2
By adjusting the mounting position of the printing spatula A card 1, it is possible to obtain accurate spacing between the print head 1 and the platen over the entire area, and the number of adjustment steps can be significantly reduced compared to the conventional method.

Figures 6 and 7 show other embodiments of the present invention;
What is different from the embodiment is that the central portion of the first guide shaft 21 is formed into a prismatic shape, and the inside of the cylindrical pusher 24 is formed into a square hole into which the prismatic portion of the first guide shaft 21 can be fitted. The first guide shaft 21 is inserted into the cylindrical pusher 24.

In this embodiment as well, the same functions and effects as in the first embodiment can be achieved, and the key and keyway shown in FIGS. 4 and 5 can be omitted.

〔Effect of the invention〕

As described above, according to the present invention, the platen and print head can be set parallel to each other with a predetermined distance maintained without adjustment during assembly.

[Brief explanation of drawings]

FIG. 1 is a schematic plan view of a print head feeding device, FIG. 2 is a conventional print head feeding device, a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a B--B in FIG. Side view seen from direction B,
4 and 5 show one embodiment of the present invention, FIG. 4 is a cross-sectional plan view of a mechanism part that changes the distance between the print head and the platen in the print head feeding device, and FIG. 5 is the same as that shown in FIG. C
6 and 7 show other embodiments of the present invention, and FIG. 6 is a perspective view of the first guide shaft, and FIG. 7 corresponds to FIG. 5. FIG. DESCRIPTION OF SYMBOLS 1... Print head, 2... Carrier, 5... Platen, 6... Frame, 11... First guide shaft, 12 ...Second guide shaft, 14...Cylindrical bush, 16...Stopper, 17...Key, 21...First guide Shaft, 24...Cylindrical bushing. 1z 5th, 40th

Claims (1)

[Scope of Claims] A first guide shaft and a second guide shaft whose both ends are respectively supported by frames and are parallel to the platen axis, and a print head are fixed and movable along the first guide shaft. a carrier whose rotation is restrained by having one end slidably engaged with the second guide shaft; and a cylindrical pulley which is fitted into the carrier with the first guide shaft inserted therethrough. The cylindrical bushing has a central axis of its outer diameter eccentric to the central axis of the first guide shaft, and is free to rotate with respect to the carrier but is restrained in the axial direction. , and the carrier slides on the first guide shaft but its rotation is restricted, and when the first guide shaft is rotated, the eccentric movement of the cylindrical pusher causes the carrier to reduce the distance between the platen and the print head. A print head feeding device characterized in that it is configured to move in a direction of change.