JPS623248Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a print head position detection mechanism for a dot printer.

Conventionally, a photocoupler is installed in a head carriage that supports the print head and moves along a guide shaft.
A dot printer that detects the position of the printing head by providing a band-shaped slit plate in the gap between the light emitting part and the light receiving part of the photocoupler is equipped with one photocoupler and one slit plate, and the slit plate is fastened with a screw member. , is held by an elastic member such as a spring. In order to increase printing speed, printers often need to perform reciprocating printing. In addition, two or more lines of printing may be consecutively printed to enlarge numbers and characters, and back-and-forth printing may be performed when printing symbols such as bar codes. In such a case, if the conventional head position detection mechanism is used, a shift in the digit direction of printing will occur. This is because during reciprocating printing, the direction of movement of the print head is opposite in the forward and backward strokes, so if printing is performed at the same printing timing, the point at which the print head wire reaches the platen will not match. is the main cause. It is also caused by looseness between the print head and the guide shaft. As described above, with conventional dot printers using a detection mechanism, it is difficult to print enlarged characters, bar codes, etc. as described above back and forth in terms of print quality.

The present invention has been developed to eliminate such drawbacks, and its first purpose is to eliminate the shift in the digit direction of printed characters in dot printers that perform reciprocating printing, so that enlarged characters, barcodes, etc. The object of the present invention is to provide a detection mechanism that does not cause misalignment at the mating portion, and a second object is to provide a detection mechanism that is easy to adjust.

The present invention will be described in detail below based on examples.

FIG. 1 shows an embodiment of the present invention, in which the print head 1
is held in a head carriage 2 and moves along a guide shaft 3, and photocouplers 4 and 5 are attached to the head carriage 2 and move together with the print head 1. The slit plate 8 is located in the gap between the light emitting section 6 and the light receiving section 7 of the photocoupler 4, and engages with a detection adjustment section consisting of an elastic member 10 and a screw member 11.
The slit plate 9 is located in the gap between the light emitting part 6 and the light receiving part 7 of the photocoupler 5, and is fixed to the printer body frame 12 by a screw member 13.

FIG. 2 is a side sectional view of the head position detection and adjustment section. To explain the printing operation as an example, the printing head 1 is guided by the guide shaft 3 and moved by another driving source, and when the printing head 1 moves from right to left, the photocoupler 5 moves along the slit plate. When moving from left to right, the photo coupler 4 prints based on the signal generated by the slit plate 8. Further, by providing two sets of detectors each consisting of a photocoupler and a slit plate, and further engaging at least one of the slit plates with the detection adjustment section, it becomes very easy to adjust printing misalignment. To explain the adjustment of the slit plate 8, first, the photo coupler 5
In order to adjust the left-to-right printing by the photocoupler 4 and the slit plate 8 without misalignment at the upper and lower joints, the screw member 11 is rotated. This allows the slit plate 8 to move to the left or right to change and adjust the printing timing.
Furthermore, since the slit plate 8 is always pressed in a fixed direction by the elastic member 10, even after adjustment by the screw member 11, the slit plate 8 is fixed without any additional fixing means. Further, since the screw member 11 can be rotated from the outside of the printer body frame 12, the slit plate 8 can be moved without stopping the operation of the printer, making the adjustment process very easy.

As explained above, the present invention provides two sets of detectors each consisting of a photocoupler and a slit plate, and furthermore, by engaging the detection rupture part of at least one of the two slit plates, the detector can be easily constructed. This enables adjustment and highly accurate reciprocating printing.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a dot printer according to the present invention, and FIG. 2 is a side sectional view of a head position detection and adjustment section. 1...Print head, 2...Head carriage,
4, 5...Photocoupler, 6...Light emitting part, 7...
Light receiving section, 8, 9...slit plate, 10...elastic member, 11...screw member, 12...printer body frame.

Claims (1)

[Scope of utility model registration request] A dot printer comprising a print head for printing arbitrary characters, numbers, symbols, etc., a head carriage that holds the print head and moves on a guide shaft, and a detection mechanism that detects the position of the print head. A print head position detection mechanism includes two photocouplers, a strip-shaped slit plate is provided between the light emitting part and the light receiving part of each photocoupler, and at least one of the slit plates is engaged with a fine adjustment mechanism. Dot printer with.