JPH06316089A - Printing timing control device for serial printer - Google Patents

Abstract

PURPOSE:To reduce noise by allowing the sound pressure waveform of printing sound to interfere by dividing a large number of printing wires into an arbitrary number of groups and specifying the shift time of printing timings at the beginning of respective groups with respect to the dominant frequency of the noise due to a printing head. CONSTITUTION:A serial printer is loaded with a printing head having a plurality of printing wire arrangements 51. That is, for example, 24 printing wires 1-24 are longitudinally arranged to the leading end of the printing head in two rows. A predetermined shift interval 102 and a predetermined row interval 101 are set to the printing wires 1-24. In this case, the printing wires 1-24 are divided into an arbitrary number of groups. When the dominant frequency of the noise generated by the printing operation of the printing head is (f), the shift time 202 of printing timings at the beginning of the respective groups is set so as to satisfy formula: {n+(1/2)}1/f (wherein n is 0 or an arbitrary positive integer).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print control system in an impact type serial printer using a print wire, and more particularly to a print timing control system for a serial printer.

[0002]

2. Description of the Related Art The impact type serial printer is
With the increasing demand for personal computers in recent years and the expansion of OA boom, many developments have been made. Even now, there is an urgent need to develop a serial printer having a high-speed copying capability for a large number of sheets to meet the needs of the market.

On the other hand, a serial printer having high speed and high printing power is noisy. The noise of the serial printer is roughly classified into a print sound generated during the printing operation of the print head and a mechanical sound generated by a mechanical unit such as a motor. Actually, the noise due to the print sound is extremely large. Therefore, noise reduction due to the printing sound of the serial printer is one of the heavy responsibilities in developing the main body of the serial printer.

Now, the printing sound generated by the conventional serial printer will be described with reference to the drawings.

In FIG. 4, reference numeral 151 is an array diagram of the print wires at the tip of the print head. In FIG. 4, 2
The four print wires are arranged in two vertical columns, forming a so-called staggered arrangement. Distance between the left and right columns, that is, column spacing 101
Is set to an integral multiple of the dot pitch.

Further, in the figure, reference numeral 152 is a diagram showing the print timing by the print wire. in this case,
The case where the print head moves to the right in the figure for printing will be described as an example. When the print head moves to the predetermined print position due to the movement of the carrier (not shown) equipped with the print head, the print is performed. The printing wire selected by the data performs the printing operation. Then, the carrier moves to the right, and when the time 203 has elapsed, the print head reaches the predetermined print position, and the print wire selected by the print data performs the print operation. Therefore, the time 203 is the printing cycle, and the reciprocal thereof is the printing frequency.

Next, the behavior of the printing sound when such a printing operation is performed will be described. In FIG.
(A) and (b) show the print timing of arbitrary two wires. Further, in the same figure, (c) and (d) are sound pressure waveforms of the printing sound generated by the printing operation of each wire.
That is, (c) in the figure is a sound pressure waveform when one wire shown in (a) is driven, where the horizontal axis represents time and the vertical axis represents sound pressure.

The print sound is a sound generated when the wire hits the paper and when the moving part collides with the inside of the print head due to the return of the wire, and as shown in FIG. Vibration of each part continues for a while and then attenuates gradually. The same applies when one wire shown in FIG. 7B is driven, and the sound pressure waveform shown in FIG. The mechanism of forming the sound waveform is almost the same, and the sound pressure waveforms in FIGS. 5C and 5D are almost the same.

On the other hand, as an example, consider a case where two print wires at timings (a) and (b) in FIG. 5 are simultaneously driven. The sound pressure waveform in this case is shown in FIG. Since the sound pressure waveforms generated by the respective print wires are (c) and (d), these waveforms are added together. This is self-evident due to the nature of sound synthesis.

Next, FIG. 6 shows the result of 1/3 octave analysis of the sound pressure waveform. In FIG. 6, the horizontal axis represents frequency and the vertical axis represents noise level. It can be seen that the print sound has various frequency components, but it is also shown that there are particularly dominant frequencies. Assuming that the frequency with the highest noise level is f, from FIG.
It can be seen that it is around [KH _Z ]. Therefore, the sound pressure waveforms of (c), (d), and (e) in FIG.
This is a periodic function of [KH _Z ].

[0011]

The print sound, which is the mainstream of the noise of the serial printer, is composed of the sound pressure waveforms of the respective print wires. Since the respective sound pressure waveforms have substantially the same shape, When a plurality of printing wires are driven, the printing sound becomes large in proportion to the number of simultaneously driven wires. The frequency characteristic of the print sound has a dominant frequency f.

[0012] However, as the analysis of the print sound is being advanced, it is generally difficult to reduce the print sound of the serial printer because it is difficult to take technical measures against the print head itself. The main measures were to attach sound absorbing material. Therefore, there is a problem that the printer is unnecessarily large and the operability and portability are poor.

[0013]

It is an object of the present invention to improve the disadvantages of the conventional example, and particularly to effectively reduce the noise caused by the printing sound by the phase control method for the dominant frequency f, thereby reducing the size of the printer. It is an object of the present invention to provide a print timing control system for a serial printer, which can improve the portability and portability.

[0014]

According to the present invention, in a serial printer equipped with a print head having a plurality of print wires, the print wires are divided into arbitrary m groups and the print operation is performed by the print head. When the dominant frequency of noise is f, the first print timing deviation time of each group is {n + (1/2)} 1 / f (however,
n is set to 0 or an arbitrary positive integer). In this way, the above-mentioned purpose is achieved and used.

[0015]

[Operation] The sound pressure waveform when driving one arbitrary printing wire is similar to the sound pressure waveform when driving another printing wire. Here, let us consider a case where, for example, two print wires are driven with a predetermined displacement time {n + (1/2)} 1 / f. In this case, as is clear,
The sound pressure waveform generated by each print wire has the same shape, and the phase is shifted by half a wavelength of the main frequency component.
When the two are added together, the peaks and valleys of the waveforms coincide with each other and are combined, whereby the amplitude of the waveforms is significantly reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 51 is an array diagram of the print wires at the tip of the print head. 24 print wires
They are roughly arranged in two columns. And in each column,
Upper print wires 1-12 and lower print wires 13-2
Reference numeral 4 has a gap 102 on the left and right. That is, the upper right print wires 1, 3, 5, 7, 9, 11 and the lower right wires 13, 15, 17, 19, 21, 23 have a gap 102, and the upper left wire 2, 2. 4, 6, 8,
10, 12 and lower left wire 14, 16, 18, 2
0, 22, and 24 are also arranged with a gap 102.

The right upper printing wires 1, 3,
5,7,9,11 and left upper wire 2,4,6
8, 10, 12 have a row spacing 101, and the lower print wires 13, 15, 17, 19, 21, 23 on the right side and the lower wire 14, 16, 18, 20, 20, 22, 24 on the left side also have rows. It has a space 101. Where the left and right column spacing is 1
01 is an integral multiple of the dot pitch. With such an arrangement, the print wires are in groups of 1-12 and 1
It is divided into 3 to 24 groups.

FIG. 2 shows an example of the print timing of the print wire. In FIG. 2, (a) shows a case where printing is performed while the print head moves to the right in the drawing. That is, when the print wires 1 to 12 reach the predetermined print positions due to the movement of the carrier (not shown) carrying the print head, the wire selected by the print data performs the print operation.

Next, the carrier moves to the right, but at the time when the shift time 202 has elapsed, it is assumed that the carrier moves just by the interval (a) in FIG. 2 (the time corresponding to the shift interval 102). Print wires 13-2 at this point
The wire selected by the print data of 4 performs the printing operation.

Therefore, when the moving speed of the carrier is v, the relationship between the deviation interval 102 and the deviation time 202 is that the deviation interval 102 is equal to “v × deviation time 202”. Further, this deviation time 202 is represented by "{n + (1/2)} / f (however, when f is the dominant frequency of the print sound,
n is an arbitrary 0 or a positive integer) ". In this embodiment, n = 0.

Subsequently, the carrier moves to the right, and when the time 203 has elapsed from the time when the print wires 1-12 performed the printing operation, the print wires 1-12 reach the next predetermined print position. , The wire selected by the print data performs the printing operation. Therefore, the time 203 is the printing cycle, and the reciprocal thereof is the printing frequency. Further, when the carrier moves to the right and the shift time 202 elapses, the wire selected from the print data among the prints 13 to 24 performs the print operation. Hereinafter, the same operation is repeated.

Next, the behavior of the printing sound when such a printing operation is performed will be described. In FIG.
(A) is a print timing of any one wire of the print wires 1 to 12, and (b) is a print timing of any one wire of the print wires 13 to 24.
(C) and (d) are sound pressure waveforms of the printing sound generated by the printing operation of each wire. Of these, (c) is a sound pressure waveform when one wire shown in (a) is driven, and the horizontal axis represents time and the vertical axis represents sound pressure. Similarly, (d) is a sound pressure waveform when one wire shown in (b) is driven. As is clear from comparison between (c) and (d) in FIG. 2, the sound pressure waveforms when an arbitrary one printing wire is driven are similar.

Now, consider the case where the two print wires shown in FIGS. 2A and 2B are continuously driven. FIG. 6E shows the sound pressure waveform in this case. (C)
As is apparent from (d), the sound pressure waveforms generated by the respective print wires have the same shape, and the phases are shifted by half a wavelength of the main frequency component. The valleys match and are synthesized, and the amplitude of the waveform is significantly reduced.

In order to further analyze the sound pressure waveform, FIG. 3 shows the result of 1/3 octave analysis of the sound pressure waveform when two print wires are driven. In the figure, the horizontal axis is frequency and the vertical axis is noise level. The solid line in the figure shows the 1/3 octave analysis result of the print sound of the serial printer according to the present embodiment. Also, the dotted line in the figure is the 1/3 octave analysis result of the printing sound of the conventional serial printer.

Assuming that the frequency with the highest noise level is f (near 8 [KH _Z ] in this case), the printing sound of the serial printer in this embodiment has this frequency of 8 [KH _Z ].
It can be seen that it is significantly reduced in the vicinity of. This is 2
This is because the drive timing of the print wire of the book is shifted by "1 / (2f)". Further, the sounds of the other frequency components are hardly affected and are not changed, but the noise level of the most dominant frequency band is reduced, and therefore the overall noise level is reduced.

The above example is the case where one is selected from the upper print wire and one from the lower print wire. Further, for example, when two wires are selected from the upper print wires, the same result as that of the conventional serial printer is obtained. However, in a general character pattern and graphic pattern, the print wires are uniformly selected from the group of upper print wires and the group of lower print wires. Noise is effectively reduced.

Here, the grouping of the upper print wire group and the lower print wire group is an embodiment of the present invention, and similar synthesis of sound pressure waveforms occurs in any combination. Therefore, in a general print pattern, the reduction effect is greatest when the same number of print wires from different groups are divided into groups that are frequently driven.

[0029]

As described above, according to the present invention, in a serial printer equipped with a print head having a plurality of print wires, the print timing of the print wires is divided into a plurality of groups and is generated by the print operation of the print head. Since the predominant frequency of noise is set to f, the print timing deviation time of a plurality of groups is made to match {n + (1/2)} 1 / f (where n is 0 or a positive integer). , The sound pressure waveforms of the print sound generated by the print operation of the print wires of each group interfere with each other, which can effectively reduce the noise generation due to the print sound for each column, which is In this respect, a print timing control system for a serial printer, which has not been available in the past, can be provided in which the size of the printer and the portability can be improved. Door can be.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a relationship between an arrangement of print wires and print timing according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a print timing of a print wire operating at a timing of a shift time corresponding to a shift interval in FIG. 1 and a sound pressure waveform.

FIG. 3 is an explanatory diagram showing the 1/3 octave analysis result of (e) in FIG. 2 in comparison with a conventional example.

FIG. 4 is an explanatory diagram showing a relationship between an arrangement of print wires and print timing in a conventional example.

5 is an explanatory diagram showing the relationship between the print timing of the print wire in FIG. 4 and the sound pressure waveform.

FIG. 6 is a diagram showing the 1/3 octave analysis result of (e) in FIG.

[Explanation of symbols]

1 to 24 print wires 101 distance between left and right print wire rows 102 gap between upper print wire row and lower print wire row 202 print timing deviation time between upper print wire row and lower print wire row 203 print cycle f Dominant frequency of printing sound

Claims (2)

[Claims] 1. A serial printer equipped with a print head having a plurality of print wires, wherein the print wires are divided into arbitrary m groups, and
When the dominant frequency of noise generated by the print operation of the print head is f, the deviation time of the first print timing of each group is {n + (1/2)} 1 / f (where n is 0 or any positive value). Print timing control method for serial printers. 2. When the print wires are divided into two rows, the print wires in each row are divided into two groups, and the dominant frequency of noise generated by the print operation of the print head is f, the first of each group 2. The deviation time of the print timing of is set to "1 / 2f".
Print timing control method for the serial printer described.