JPS6343231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer position pulse check system that prevents malfunctions when noise or the like enters the printer's operation signal transmission line.

The schematic structure of this type of printer is shown in FIG. 1. Print media 1 such as roll paper, passbook, etc.
Desired characters are printed in several lines horizontally. At this time, the printing medium 1 is intermittently fed in a direction perpendicular to the printing direction while being supported by a platen 2 that supports the medium. The printing unit 3 impacts the desired type onto the print medium 1. For example, the print head 3-1 is composed of a crown-shaped arrangement of 64 characters and 128 characters in total in two upper and lower rows, and the print head 3-1 is driven to rotate. a drive mechanism section 3-2 housing a type selection motor and a hammer source for impacting one type toward the medium 1; and a ribbon cartridge 3-3 housing red and black ink ribbons.
Consists of etc. The printing unit 3 moves along the movement axis 4 in the direction of arrow A in the figure to perform a spacing operation.
Note that the moving shaft 4 is rotated by the space motor 5, and a helical groove is formed on the moving shaft 4, so that the printing unit is moved by the feeding operation of the helical groove that accompanies the rotation. 3 can do the spacing. Each time one horizontal row of printing is completed, the printer returns to the direction of arrow A' in the figure. Although not shown, a control circuit board is provided on which a circuit for controlling the printing unit 3, the motor, the hammer drive source, etc. is mounted. Next, FIG. 2 is a perspective view of the hammer driving section of the serial printer shown in FIG. 1, viewed from the platen 2 side with the printing medium 1 removed. Reference numeral 6 denotes a DC motor, which moves the print head 3-1 toward the platen 2 through a gear 7 and performs a hammer operation in the direction of arrow S.

Although not shown in FIG. 2, the printing unit 3 includes a motor that rotates the print head for character selection and a transistor that rotates in synchronization with the print head. The transducer generates two position pulses that are out of phase with each other for each character pitch rotation of the print head. FIG. 3 is a block diagram for explaining generation of position pulses and counting of the pulses. In FIG. 3, a sinusoidal position detection signal (hereinafter referred to as a position signal) PS obtained from a transducer 11 is amplified 12, and a pulse generation circuit 13
pulse at the positive and negative peaks of the position signal PS (hereinafter referred to as position pulse)
Generates PP. FIG. 4 is a time chart for explaining the operation of FIG. 3, and FIG. 4A shows the position signal PS, and the circle mark in the figure shows the position where the print head can stop rotating. FIGS. 4B and 4C show position pulse trains PP and PP, respectively. RDCS in FIG. 3 and D in FIG. 4 indicate the print head rotation direction designation signal, and by calculating this signal and position pulses PP and PP in the logic operation circuit 14, the print head is rotated in one direction. The number of position pulses is counted by the current position counter 15, and the rotation of the print head can be controlled. Therefore, since the number of pitches to be rotated when the print head is rotated to select a type is determined from the count value of the current position counter 15, the number of pitches is set in advance in the target position counter 16 as the pulse count number. Then, when the rotation direction designation signal mentioned above is released, the counter 1
5 and 16 are compared by a comparator 17,
If they are equal, it can be seen that the number of rotational pitches of the print head is normal. If they are not equal, it is desirable to interrupt the hammer drive of the print head because there is a risk of printing erroneous characters. In this case, the line from the generation of the position signal PS to the comparator 17 is likely to be contaminated with noise, and when the print head is originally in the correct position, the counter 15 counts more of the noise as a position pulse, and the counter 16 In some cases, a different value was displayed and a malfunction occurred.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks and to provide a printer position pulse check system that can completely distinguish between normal operation and malfunction even if noise or the like enters the printer's operation signal transmission line. .

Embodiments of the present invention shown in the drawings will be described below. FIG. 5 is a block diagram showing the configuration of the first embodiment of the present invention, in which the same reference numerals as in FIG. 3 indicate the same components. Counters 18-1 and 18-2 in FIG.
For each pulse train of position pulses PP and PP, only one pulse train is counted regardless of the rotational direction of the print head. That is, the counter 18-
1 counts PPI, and counter 18-2 counts only PP. Comparator 17-2 is similar to comparator 17 in FIG.
The set value of the counter 18-1 is compared with the count value of the counter 18-1. When the comparator 17-2 performs a comparison operation in the comparator 17-1, the count values of the counters 18-1 and 18-2 are simultaneously compared.
At this time, as can be seen from the time chart in Figure 4, position pulses PP and PP are generated in pairs, so the count values of counters 18-1 and 18-2 are originally the same number, and each pulse If noise pulses are commonly mixed in the transmission lines, no abnormality will occur in the count values, but if the noise pulses are mixed in only one transmission line, the count values will not be equal, indicating that the cause is noise or other disturbances. Since it is necessary to determine whether or not the print symbol is printed, the logical operation circuit 19 does not output a print symbol in response to the print command. That is, since the position pulses generated with different phases by the two counters 18-1 and 18-2 are counted separately, only when the counted values of each counter match are printed as normal, and each Reset the counter. Note that if the counted value does not match the preset expected rotation value of the print head, printing will not be performed and the print head will be reset.

Next, FIG. 6 shows the counters 18-1, 18-2 and comparator 1 of FIG. 5 as the main parts of the second embodiment of the present invention.
It is a block diagram which shows the part corresponding to 7-2. 20
is an up-down counter, which during normal operation alternately applies position pulses to the count switching signal terminal U/D in the increasing direction and decreasing direction, and also alternately applies position pulses to each count terminal. . That is, a signal indicating an increase or decrease count direction is applied to the U/D terminal, and the count value is increased or decreased each time a pulse is applied to the "count" terminal. Therefore, in Fig. 6, it is normal operation that the position pulses PP and PP arrive alternately in time, so in that case, the U/D terminal repeats increase and decrease instructions, and at the same time the count terminal is Increase or decrease the pulse count.
That is, the upper side of the OR circuit for the position pulses PP, PP is used to input each pulse alternately to the count terminal of the up-down counter 20. The lower side of the OR circuit is used to instruct the U/D terminal of the up-down circuit 20 to increase the count using PP, and to instruct the count to decrease using a signal obtained by inverting the phase of PP.

Further, the up-down counter 20 is provided with a counter value comparator 21, and when the comparator 17-2 compares the set value of the counter 16 and the value of the counter 18-2 and detects the same value, a detection signal to that effect is sent. is applied to the counter value comparator 21 to perform a detection operation. At that time, when the counter value of the up-down counter 20 is zero, the detection signal is applied to one terminal of the AND operation circuit 19, and at the same time, the output of the comparator 17-2 and the signal from the print command terminal are all calculated. . Therefore, under normal conditions, all the signals are, for example, "1", so the print signal terminal becomes "1" and a printing operation can be performed. When all the applied signals are not equal to predetermined values, the print signal terminal becomes "0" and printing cannot be performed.

In this way, according to the present invention, two position pulse trains are generated from the same signal, and the printing operation is not performed unless they are counted separately and match, so that erroneous printing can be accurately prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the general configuration of a serial printer, FIG. 2 is a perspective view of the hammer drive section in FIG. 1,
FIG. 3 is a block diagram explaining the generation and counting of position pulses in FIG. 1, FIG. 4 is a time chart for explaining the operation of FIG. 3, and FIG.
FIG. 6 is a block diagram showing the structure of the main part of the second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Printing medium, 2... Platen, 3... Printing unit, 3-1... Printing head, 3-2... Drive mechanism section, 3-3... Ribbon cartridge, 4...
...Moving axis, 5... Space motor, 6... DC motor, 7... Gear, 11... Transducer,
12...Amplifier, 13...Pulse generation circuit, 14
...Logic operation circuit, 15...Current position counter,
16...Target position counter, 17, 17-1, 1
7-2... Comparator, 18-1, 18-2... Counter.

Claims (1)

[Claims] 1. A set of two position pulses with a phase difference between each other is generated every one type pitch rotation to form a pulse train, and it is detected that the two position pulses have been generated normally. In a check device for generating position pulses of a printer that prints a predetermined type character at a target position, two counters take out the position pulses for each phase from the beginning of one character pitch rotation and start counting; 1. A position pulse generation check device for a printer, comprising a comparator that compares the counts of each counter at a scheduled position, and a control section that controls sending of a print command based on the output of the comparator.