JPS6330154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer that has a print driving means in which a plurality of printing electromagnets are densely mounted, and that prints by simultaneously energizing the plurality of electromagnets.

Conventional printers that use electromagnets to drive the printing elements use a so-called suction drive method in which the printing elements are driven by the suction action of the electromagnet, and permanent magnets, or they use excitation current to flow in advance to bring the printing elements into the suction state. In addition, there is a so-called release drive method in which the printing element is driven by the restoring force of a spring or the like by canceling the magnetic field of attraction, and both have different characteristics in the driving method and the mounting method of the electromagnet. Recently, there has been a strong demand for these electromagnets to be made smaller and more densely packaged, and when a large number of electromagnets are mounted close to each other at a high density, the printing element may malfunction due to magnetic interference between the electromagnets. Stability has become an issue.

The present invention is intended to solve this problem, and is designed to vary the length of time the excitation current is passed depending on the total number of electromagnets that are energized at the same time.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, which is a print drive control circuit for an impact type dot printer, and FIG. 2 is a time chart for explaining the operation of each part in FIG.

In FIG. 1, PD ₁ to _{PD 7} are print data signals supplied corresponding to each print wire, and in this embodiment, a print head is assumed to have seven print wires in one vertical column. These print data signals PD ₁
.about.PD ₇ is supplied every time the print head moves by a predetermined pitch based on a dot pattern signal from a character generator (not shown).

Print data signals PD ₁ to _{PD 7} are each AND gate
The signal enters AG ₁ to AG ₇ and is sent to the driving magnet number detection circuit 1. The drive magnet number detection circuit 1 counts logical "1" signals indicating printing among the print data signals PD ₁ to _{PD 7} , and the total number n is n≦2, 2≦n≦5, or 5<n. It determines which of these relationships exist and generates one of drive quantity signals N ₁ to _{N 3.} If n is ≦2, N ₁ , 2
N ₂ if ≦n≦5 and N ₃ if 5<n
occurs. This drive magnet number detection circuit 1 does not need to be particularly limited in its configuration as long as it performs the above-mentioned function. It may be configured with a decoder that sends out signals, or it may be configured with other configurations.

Driving quantity signal N ₁ which is the output of the above detection circuit 1
~ _N3 is applied to one input of AND gates _AG8 ~ _AG10 . The other input of these AND gates AG ₈ to _{AG 10} is the time signal from timer 2;
The lengths of T ₁ to _{T 3} are as shown in Figure ₂ d to f.
The relationship is T ₂ < T ₃ , and the shortest time signal T ₁ is sent to AND gate AG 8, the next longest time signal T ₂ is sent to AND gate AG ₉ , and the longest time signal T ₃ is sent to AND gate AG ₈ . Added to ANDGATE AG ₁₀ . The outputs of these AND gates _AG8 to _AG10 are given to the OR gate OG, and the output G of the OR gate OG is used as a driving gate signal to drive the AND gates _AG1 to AG10.
Commonly applied to the other input of AG ₇ .

The timer 2 is started by a timing signal T generated every time the print head moves a certain pitch. The temporal relationship between the sending of the print data signals PD ₁ to _{PD 7} and the generation of the timing signal T is shown in Figure 2a,
As shown in c. The magnets for driving each printing wire are energized by supplying drive signals DV ₁ to _{DV 7} , which are the outputs of AND gates AG ₁ to _{AG 7} , to the printing magnet drive circuit 3.

In the print drive control circuit configured as described above, when the print data signals PD ₁ to _{PD 7} are supplied, the total number of print magnets that are energized at the same time is detected by the drive magnet total number detection circuit 1, and the drive quantity signal is
Any one of N ₁ to N ₃ is output. The AND gates into which the drive quantity signals N ₁ to N ₃ are input are determined one-to-one in relation to the time signals T ₁ to T ₃ as described above, so the AND gates are determined by which drive quantity signal is output. The time signals output from gates _AG8 to _AG10 are selected. In other words, AND gates AG ₈ to AG ₁₀ are used to generate a drive signal with a duration corresponding to the total number of printing magnets that are energized at the same time, and as the total number of magnets that are energized at the same time increases, the time increases It selectively sends out time signals. The time signal is applied to the AND gates AG ₁ to _{AG 7} via the OR gate OG ₁ and gates the print data signals PD ₁ to _{PD 7} to determine the application time of the drive signals DV ₁ to _{DV 7} to the print magnet drive circuit 3. Control.

As described above, according to the present invention, since the driving time of the printing magnet changes depending on the total number of magnets driven simultaneously, the operation of the printing element is always maintained regardless of the influence of magnetic interference between the magnets depending on the total number of driving magnets. can be stabilized,
This has the effect of improving print quality. Another advantage is that no special drive circuit or power supply for the printing magnet is required.

The present invention is applicable not only to the impact type dot printer of the above embodiment, but also to any printer in which printing magnets are mounted at high density.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a print drive control circuit showing one embodiment of the present invention, and FIG. 2 is a time chart showing the temporal relationship of the operations of each part in FIG. 1... Drive magnet number detection circuit, 2... Timer, 3... Print magnet drive circuit.

Claims (1)

[Scope of Claims] 1. In a wire dot printer that prints by selectively driving a printing element driving means in which a plurality of electromagnets are densely mounted while moving along a print line, a wire dot printer is provided corresponding to each electromagnet. a printing data signal, a means for detecting the number of electromagnets driven simultaneously by this signal, and a timing signal generated every time the printing element driving means moves a certain pitch;
A wire dot printer comprising: means for transmitting a time signal having a length corresponding to the number of electromagnets; and means for gating the print data signal using the time signal to obtain a drive signal for the electromagnets.