JPH0825285B2 - Wire print head driving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a method for driving a plurality of print wires and a wire print head for individually driving each of the print wires, the wire print head having the same number of magnetic circuits as the print wires. The present invention relates to a wire printing head driving method for a wire dot printer that prints one character by driving the plurality of printing wires by dividing them into two steps, one before the other and two times after the other.

[Conventional technology]

Conventionally, as shown in the plan view of FIG. 3, the print head of the wire dot printer is configured so that the dot elements 1 by the print wires are arranged in one vertical column, and the dot matrix (pixel pattern) used is as shown in FIG. In general, a full matrix representing one character in the horizontal 8 dots and a pseudo matrix representing one character in the horizontal 12 dots shown in FIG. 4 are generally used.

By the way, since the printing speed of the wire dot printer is limited by the response period of the dot element of the print head, the minimum dot interval (pixel interval) should be increased when the same dot element is continuously driven in the lateral direction. It is well known that the printing speed can be increased by operating it. However, in the wire dot printer having the above configuration, if the minimum dot interval is increased, the image quality correspondingly decreases, so there is a limit to the expansion of the minimum dot interval. Therefore, there is a limit in increasing the printing speed.

For this reason, in recent years, as shown in the front view of FIG. 6, two sets of dot elements 1 formed by printing wires are arranged in parallel, and these dots are driven twice in front and rear stages to drive one dot. The head was developed.

In this case, the dot element array on the right side is columns 1, 2,
It is controlled so that 5,6,9 are printed and the remaining columns 3, 4, 7, 8 are printed by the dot element array on the left side. In this case columns 10-12
Is a non-printing area called clearance between characters.

This is illustrated in the matrix exploded explanatory view of FIGS. 7 (a) and 7 (b), and as is apparent from the drawing, the interval d between the dots continuous in the lateral direction is the head row in FIG. In case of two rows of heads,
Printing speed can be doubled.

FIG. 8 is a time chart showing a conventional example of a wire printing head drive system of this type of wire printer.
In the figure, head drive timing 1 is the drive timing of one print wire row of the two print wires, and head drive timing 2 is the drive timing of the other print wire row.

Hereinafter, the print wire driven at the head drive timing 1 will be referred to as the pre-stage drive print wire, and the print wire driven at the head drive timing 2 will be referred to as the post-stage drive print wire.

That is, in the conventional method, the print head has a print interval D / 2.
The dot pulse is detected each time the vehicle travels a predetermined distance corresponding to the above, and based on this dot pulse, the pre-driving print wire and the post-driving print wire are driven at predetermined head drive timings 1 and 2 shown by solid lines in FIG. However, the printing process was performed.

[Problems to be solved by the invention]

However, according to the prior art with the above-described configuration, in a small dot printing head having a large number of printing wires, since the attraction force on the core surface due to the permanent magnet cannot be increased, the attraction of the spring that drives the printing wires is reduced. The flexural energy at that time is small, and the operation (displacement 1) of the preceding-stage drive print wire driven at the head drive timing 1 is not completed between the head drive timings 1 and 2 in FIG. The latter drive print wire is driven by this, and the drive current overlaps. On the other hand, in the small dot print head, since the magnetic circuits corresponding to the respective print wires are arranged close to each other, the influence of interference between the magnetic circuits occurs due to the overlap of the driving current.

FIG. 9 is a cross-sectional side view of an essential part showing the influence of interference between the magnetic circuits. In the figure, 2a, 2b and 2c are electromagnet cores and 3
Is a degaussing coil, and 4 is a spring having a printing wire. The degaussing coil 3 attracts the spring by the magnetic flux of the permanent magnet shown by the solid line when the drive current is not applied.

When a driving current is applied to the degaussing coils 3 of the core 2a and the core 2c, a magnetic flux indicated by a broken line is generated, and this magnetic flux is generated by the core.
In the sneak core 2b as a leakage magnetic flux of 2b, the direction is the same as the direction of the magnetic flux that attracts the spring 4, and the attractive force of the spring 4 increases. Hereinafter, this phenomenon is referred to as the influence of magnetic interference.

FIG. 10 shows a displacement waveform and a speed waveform of the front and rear drive printing wires driven by the head drive timings 1 and 2 of the conventional example, and the head drive print wires driven by the head drive timing 1 are displaced while the heads are moving. When a large number of rear-stage drive print wires are driven at drive timing 2, the front-stage drive print wires driven at head drive timing 1 are displaced by the increased attraction force as in core 2b of FIG. 9 due to the influence of the above-mentioned magnetic interference. As shown by the broken line of the velocity waveform,
The return speed increases and the rebound after being sucked into the core increases.

When the pre-driving print wire driven at the head drive timing 1 is driven in the next printing due to the influence of the increased re-pound, the printing power becomes uneven and the printing quality is deteriorated.

Therefore, according to the prior art, there is a limit to the downsizing of the dot printing head and the increase in the number of printing wires, which limits the downsizing of the apparatus and the high image quality due to the large number of printing wires. I got it.

In view of the above problems, the present invention solves the problem that the magnetic interference between adjacent magnetic circuits affects the drive of the print wire, and the small overlap type dot print head or the overlap type dot having a large number of print wires. It is an object of the present invention to obtain a wire printing head drive system that does not deteriorate the printing quality even in the printing head.

The present invention further overcomes the limitations of downsizing the dot printing head and increasing the number of printing wires by maintaining high printing quality in a compact overlapping dot printing head and an overlapping dot printing head having a large number of printing wires. Then
It is an object of the present invention to realize a small and low-priced wire-dot printer that performs high-speed printing by over-printing and to achieve high image quality by using a large number of printing wires.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention eliminates the timing at which the drive current of the post-stage drive print wire is energized to the place where the drive current of the pre-stage drive print wire is cut off, thereby accelerating the suction of the pre-stage drive print wire. There is no room for magnetic flux.

That is, the present invention is a wire printing head mounted with a plurality of printing wires and a magnetic circuit for driving each printing wire,
A method for driving a wire print head of a wire dot printer, which performs a printing process by driving the plurality of print wires in two stages, front and rear, at a timing of overlapping.
It is characterized in that the number of drive print wires in the subsequent stage is monitored, and when the number of drive print wires in the subsequent stage exceeds a predetermined number, the drive time of the drive print wires in the previous stage is corrected to be longer than the normal set time.

[Work]

According to the present invention having the above configuration, when the magnetic interference between the adjacent magnetic circuits increases, it is judged by monitoring the number of drive print wires in the subsequent stage, and when the magnetic interference increases, the print wire drive time in the previous stage is determined in advance. The magnetic flux that accelerates the suction of the preceding drive printing wire by eliminating the timing that the driving current of the following drive printing wire is energized to the place where the driving current of the preceding drive printing wire is cut off. There is no room for the occurrence of.

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the first embodiment of the present invention.

In the figure, reference numeral 5 is a print operation mechanism including an overlap type dot print head for performing printing by driving the print wire in two stages, front and rear, as shown in FIG. 6, 6 is a drive circuit of the print operation mechanism, and 7 is a drive circuit. A microprocessor (CPU) that controls the operation of the entire wired printer, 8 is a read-only memory (ROM) that stores programs and fixed data, and 9 is a random access memory that temporarily stores data received from the outside. (RAM), 10 is a timer (TM) for counting time, 11 is driven by a command from CPU7
I / O driver, 12 or more CPU7, ROM8, RAM9, TM10, I / O
A bus line for connecting the driver 11.

The CPU 7 receives control data, which is usually referred to as a control code such as character pitch designation or line feed command, stored in the ROM 8, and also receives print data from the interface unit (not shown) in the RAM 9 for one line. Is converted into a print operation signal by the control data.

At the same time, the CPU 7 monitors the presence / absence of the drive print wire in the subsequent stage and the number of drive lines by the converted print operation signal, and when there is no print wire to be driven in the latter stage, and there is a drive print wire only in the former stage, or it is driven in the latter stage. If the number of printing wires to be printed is less than the number X of printing wires determined by the characteristics of the wire printing head, for example, 4 or less, no correction processing is applied to the printing operation signal, that is, the normal head drive time is applied to the preceding and succeeding stages. Control the drive print wire to operate. If there are n front and rear drive wires, and more than X print wires are driven in the subsequent stage, the print operation signal is set to increase the drive time of the print wires driven in the preceding stage by, for example, 50 to 150 μsec. Add a correction.

The CPU transmits the print operation signal thus configured to the drive circuit 6 of the print operation mechanism 5 to execute the print processing.

The print operation mechanism detects a dot pulse each time the print head travels a predetermined distance corresponding to the print interval during forward and reverse movements while the print head makes one reciprocation, and this dot pulse is used as the starting point. The printing process is performed in accordance with a pulse having a time width required to drive the printed wire.

The operation of this embodiment having the above configuration will be described with reference to the time chart of FIG. Here, head drive timing 1 is the drive timing of the front stage drive print wire, head drive timing 2 is the drive timing of the rear stage drive print wire, T ₁ is the drive time of the front stage drive print wire, and T ₂ is the drive time extension (this embodiment). , 50 to 150 μsec), T ₃ is the drive time of the rear drive printing wire, and printing is performed by the front drive printing wire and the rear drive printing wire in one cycle time. One cycle time is the minimum drive time that the print wire can be driven.

When a signal for starting the printing operation is sent to the CPU 7 by the command means (not shown), the CPU 7 receives the control signal from the program on the ROM 8 and receives the print data to the RAM 9 from the interface portion (not shown). When the received data for one line is accumulated, it is converted into a print operation signal by the control data.

When the CPU 7 further has a print wire that is driven only at the head drive timing 1 and does not have a print wire that is driven at the head drive timing 2 by the converted print operation signal,
Alternatively, when the number of print wires driven at the head drive timing 2 is less than X, no correction processing is added to the head drive times T ₁ and T ₃ . If there is a print wire that is driven at both head drive timing 1 and 2, and if there are more than X print wires that are driven at head drive timing 2, add T ₂ to head drive time T ₁ and add T ₁ + T ₂ , T ₃ is corrected.

In the dot print head of the print operation mechanism 5, there is a print wire that is driven at both head drive timings 1 and 2, and if there are more than X print wires that are driven at head drive timing 2, the above correction processing is performed. By controlling the printing operation control by driving the preceding drive printing wire with T ₁ + T ₂ , the magnetic flux that circulates is canceled out, the return speed of the preceding drive printing wire becomes normal, and only the normal rebound occurs and the next I want to print.

As the second embodiment of the present invention, the number of drive printing wires in the subsequent stage is more than X, and the number of drive printing wires in the previous stage is 1 or more.
Only when you are hit repeatedly at the timing of the time
The method of correcting the drive time of the pre-stage drive print wire, which is executed in the embodiment of FIG. A practical example of printing is when the same character is repeatedly stroked.

This is because the printing operation becomes unstable due to the increase in the rebound of the front-stage driving print wire due to the influence of the magnetic interference of the rear-stage driving print wire. The front-stage driving print wire is driven at the drive timing 1-2 after one cycle time. Since the time is remarkable, the heat generated by the degaussing coil can be suppressed as much as possible by setting the driving time of the preceding drive printing wire to be extended only at this time.

In addition, as a third embodiment of the present invention, when the number of printing wires is large, the determined number of printing wires X is divided into stages, for example, 2 to 3 stages, which are defined as X ₁ and X ₂ . The number of printing wires driven at head drive timing 2 is x ₁ ≤ N
<Time of T ₂ when X ₂ lines is a certain time (T ₂ ) ₁ , eg 80 μse
When c, X ₂ ≤ n, the time of T ₂ is (T ₂ ) ₂ , for example 150 μsec
Alternatively, a method may be adopted in which the drive time of the front-stage drive print wire is gradually increased in accordance with the degree of influence of magnetic interference due to the number of drive lines of the rear-stage drive print wire.

〔The invention's effect〕

As described in detail above, according to the present invention, in the wire printing head drive system of the wire dot printer for performing the printing process by the overlap type wire printing head, the latter stage driving is performed when the magnetic interference between the adjacent magnetic circuits increases. Judging by monitoring the number of print wires, when the magnetic interference increases, the print wire drive time of the previous stage was corrected in advance to be longer than the normal set time. It is possible to eliminate the timing at which the drive current of the rear-stage drive print wire is supplied, and accelerate the suction of the front-stage drive print wire to eliminate the room for the generation of magnetic flux that causes variations in the printing force. As a result, there is an effect that the printing quality is not deteriorated even when the printing process is performed by the small-sized overlap type dot print head or the overlap type dot print head having a large number of print wires.

Further, according to the present invention, even if a small overlap type dot print head or an overlap type dot print head with a large number of print wires is used, high print quality is guaranteed, so high speed printing is performed by the overlap type print. There is an effect that a wire-dot printer is small and low-priced, and a large number of printing wires can realize high image quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing the first embodiment of the present invention, and FIG.
FIG. 3 is a time chart showing the operation of the embodiment, FIG. 3 is a plan view showing an example of dot elements of a general dot printing head, FIG. 4 is an explanatory view showing a pseudo matrix by the same dot element example, and FIG. FIG. 6 is a plan view showing an example of dot elements of an overlap type dot printing head, FIG. 7 is an exploded view of a matrix by the same dot element example, and FIG. 8 is a conventional diagram. 9 is a time chart showing the technique, FIG. 9 is a side sectional view showing the problem of the conventional technique, and FIG. 10 is a waveform diagram showing the problem of the conventional technique. 1 ... Dot element example, 2a, 2b, 2c ... Core, 3 ... Degaussing coil, 4 ... Spring, 5 ... Printing mechanism, 6 ...
Drive circuit, 7 ... CPU, 8 ... ROM, 9 ... RAM, 10 ... T
M

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-156271 (JP, A) JP-A-61-222760 (JP, A) JP-A-53-68520 (JP, A) JP-A-58- 55254 (JP, A) JP 63-118268 (JP, A) JP 60-179271 (JP, A)

Claims (3)

[Claims] 1. A printing process is performed by driving a wire print head having a plurality of printing wires and a magnetic circuit for driving each of the printing wires in two stages, front and rear, at the timing of overlapping the plurality of printing wires. In the method of driving the wire print head of the wired printer, the number of drive print wires in the subsequent stage is monitored, and when the number of drive print wires in the subsequent stage exceeds the preset number, the drive print wire drive time in the previous stage is A method for driving a wire print head, which is characterized in that correction is performed so as to lengthen the wire. 2. A cycle time from the timing at which the drive printing wire at the preceding stage is driven to the timing at which the drive printing wire at the preceding stage is driven next is defined as one cycle time, and the number of driving printing wires at the subsequent stage exceeds a predetermined number.
The wire print head according to claim (1), wherein the drive print wire drive time of the previous stage is corrected only when the drive print wire of the previous stage is similarly driven in the next cycle time. Driving method. 3. A monitoring standard for the number of drive printing wires in the subsequent stage is provided stepwise, and an extension time of the printing wire drive time of the preceding stage is provided stepwise in accordance with the step, and the monitoring standard for the number of driving print wires in the subsequent stage is provided. The method for driving a wire print head according to claim (1), characterized in that the printing wire drive time of the preceding stage is corrected stepwise in accordance therewith.