JPS5847994B2 - serial dot printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a serial dot printer, and more particularly to a dot printer that detects a failure when a print head is running and takes desired action. Concerning safety equipment.

A print head is mounted on a carriage, and while sliding the carriage in a predetermined direction, wires arranged in a predetermined manner within the print head are selectively driven to print a character pattern on printing paper from a combination of dots. Wire matrix type serial blinks are known.

For example, as shown in FIG. 1, a plurality of wires are regularly arranged in the print head 1, and by selectively driving the corresponding magnet, the wires are made to fly out in 6 directions of the ink ribbon, and dots are printed on the printing paper. A certain character pattern is formed from the combination.

The print head 1 is mounted on a carriage 4, and
A drive belt 2 is fixed to the carriage 4.

By driving the drive belt 2 by a motor (not shown), the carriage 4 is guided by the shaft 3 and slid.

At the rear of the shaft 3 on which the carriage 4 slides, a video film 5 having slits at intervals of printing dots is arranged, and a photo sensor installed at the rear of the carriage 4 detects the slits in the video film 5 and prints. Controls dot pitch.

On the other hand, recent printers have become smaller and lighter,
Printers installed in a certain location are susceptible to external shocks, vibrations, and the like.

If such an influence occurs, an error will occur in the printing dot pitch detected from the video film 5, and the dot pitch of the printed dot pattern will shift, resulting in incorrect printing or characters that are difficult to see.

Especially in the case of wire matrix type serial printers, wires that pop out while the print head is running can get caught on the ink ribbon, disrupting the print head's run, or even stopping it, causing erroneous printing. It is the cause of this.

Therefore, an object of the present invention is to eliminate the problems of the prior art as described above, and to detect abnormality in the running of the print head dot by dot, and to prevent erroneous printing caused by the abnormality in the running of the print head. The purpose of the present invention is to provide a serial type dot printer with the following features.

The present invention provides a pulse generating means for generating pulses at a constant period in units of dots as the print head runs, a delay means for delaying the pulses output from the pulse generating means for a fixed period of time, and an output from the delay means. It has means for comparing and collating the pulses from the pulse generating means.

Print head movement is disturbed due to vibrations and shocks of the printer itself.

That is, the running speed of the print head suddenly increases or decreases.

Along with this, the pulses output from the pulse generating means are also disturbed, but the present invention detects this by means of comparison and verification means, and takes measures such as stopping the print head from running or notifying the operator of this fact. You can take it.

According to the present invention, it is not only possible to easily detect disturbances in the running of the print head due to vibrations and shocks of the printer itself, but also to detect dots in a dot-based manner, so it is possible to take measures to deal with dots. , misprinting is also prevented.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 2, a timing pulse generation circuit 7 generates a timing pulse of a constant period in units of dots.

This timing pulse is generated by, for example, optically detecting slits marked at dot intervals on the video film 5 in FIG. 1 as the print head runs, and converting the detected slits into electrical signals.

Timing pulses output from the timing pulse generation circuit 7 are supplied to the delay circuit 8, timing counter 11, and AND gate 1-12, 13, respectively.

The output of the delay circuit 8 is given to the delay circuit 9 and the AND gate 12, and the output of the delay circuit 9 is given to the AND gate 1.
given to 3.

Delay circuits 8 and 9 each delay the timing pulse by a fixed time shorter than its timing interval.

Therefore, when there is a running abnormality in the print head and the timing pulse output from the timing pulse generation circuit 7 is disturbed (that is, it becomes faster or slower), the AND gate 12 outputs this disturbed pulse and the delay circuit 8. are compared with the delayed pulses and if they match, the OR gate 14
The fault signal generation circuit 10 is operated via the.

The quimming counter 11 counts the timing during which the print head travels for one line.

For example, if one character is printed with 5 dots horizontally and 7 dots vertically, and 80 characters are printed in one line with the dot between characters as 1 dot, then (5 + 1) x 80 = 480 timing pulses will be counted, and the 480th When the timing pulses are counted, a signal is output to the AND gate.

This counter 11 is effective in detecting when the print head travels slow at the 480th final dot position. If an abnormality is detected at this time, the output of the AND gate 13 causes the fault to be detected via the OR gate 14. Signal generation circuit 10 is operated.

When a fault signal generation circuit 10 detects that an abnormality has occurred in the running of the print head, it issues a signal to that effect by displaying a lamp or sounding a buzzer to notify the operator.

Furthermore, in order to prevent erroneous printing, it is desirable to immediately stop the print head when a fault occurs; in this case, the fault signal generation circuit 10 stops driving the motor for driving the print head. This is done by issuing a signal to the effect that the

Therefore, even if the print head is disturbed and the dot pitch is shifted due to vibration, shock, etc. or a momentary abnormality in the power supply while the print head is running, this can be easily detected dot by dot. and take appropriate countermeasures.

Note that this embodiment can be applied not only to serial type impact printers such as known wire matrix type printers, but also to non-impact type serial printers.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a wire dot printer, and FIG. 2 is a block diagram showing a failure detection circuit according to an embodiment of the present invention. 1: Print head, 2: Drive belt, 4: Carriage, 7
: timing pulse generation circuit, 8, 9: delay circuit, 10
: Failure signal generation circuit, 11: Timing counter.

Claims (1)

[Scope of Claims] 1. In a serial dot printer that prints characters, etc. consisting of a combination of dots while moving the print head in a predetermined direction, a timing pulse is generated at a fixed period in units of dots as the print head moves. a pulse generating means; a delay means for delaying the pulse output from the pulse generating means for a period shorter than the cycle of the timing pulse;
The apparatus further comprises means for comparing the output from the delay means and the pulse from the pulse generation means, and means for generating a signal to this effect when a running abnormality of the print head is detected based on the comparison result of the comparison means. Serial type dot printer with special features. 2. The serial type dot printer according to claim 1, wherein the comparison means is an AND gate.