JPS58116170A - Printing control system for dot printer - Google Patents

Abstract

PURPOSE:To make it possible to obtain a high quality print by a method wherein the width of excitation of each of drive coils is varied every drive timing for printing pins in proportion to the level of a drive voltage so that the torque on each of the printing pins becomes substantially constant. CONSTITUTION:The drive coils L1-Ln are provided for the printing pins within a printing head, respectively, and the common drive voltage Vcc to be impressed on the coils L1-Ln is detected by dividing the voltage into suitable widths. To perform such detection, a number of comparators C1-Cn are connected parallel to a detecting section and the drive voltage Vcc is impressed upon the positive sides of the comparators, respectively. Then the voltage Vcc is compared to detecting volages E1-En and the results of comparison are inputted to CPU so as to detect the level of the drive voltage Vcc. After that, the time of impression of the voltage Vcc is adjusted according to the detected level of the drive voltage so that the torque acting on each of the printing pins becomes substantially constant to thereby equalize the thickness of printing.

Description

Detailed Description of the Invention α) Technical Field of the Invention The present invention changes the excitation width of each drive coil according to the level of the print head drive voltage at each timing of driving each print bin, thereby increasing the print bin torque. The present invention relates to a printing control method for a dot printer that allows high quality printing to be obtained by keeping 9 substantially constant.

■Prior art and problems As shown in Figure 1, the print control system of the conventional dot printer connects a plurality of comparators C1%C2''...Cn in parallel to the print head drive voltage VCC detection section. , each comparator cl, c.

,...Cn is the verification voltage E1%B2,...
・Output 10- or -11 by comparing with En
is sent to the CPU via input port 1, and this CPU
Then each of the above comparators C1% C2,...C
Depending on the combination of n outputs, an appropriate voltage width as shown in Figure 2 can be obtained.
, ■, ■, ■, ■, determine the level of the skeleton drive voltage VCC, and reset the timer 2 by 1 according to the voltage level determination result J to set the voltage ranges ■, ■, ■, ■, in advance.
7twJIm width (mll waiting time T was controlled. Then, the print information DI for the first bin
When inputted, the first gate (Gl) opens and the first state moving coil Llk is energized for the above excitation duration T, and the second and subsequent bins are similarly energized. But in this case, the second
As shown in the figure, 1 print head drive turtle pressure vcc is Bt (
Since the excitation width of the drive coil is constant TI from Emax ) to E20 voltage width ■, the printing bottle torque Q, which is proportional to (voltage) x (excitation width), changes as shown by the diagonal line Ql in Figure 2, and this voltage The print bottle torque Q is large when the voltage BxO is the highest within the width (2), and is small when the voltage B2 is the lowest. Therefore, the printing dots caused by the driving of the printing bin have uneven shading, and the printing quality has deteriorated. Further, at the high voltage E1 within the above voltage range (2), the printing bottle torque Q was excessive and the printing paper could be torn. In the next voltage width (■) from E2 to E3, the excitation width T2 is larger than the excitation width Tl, so the printing bottle torque Q at this time is as shown by the diagonal line Q2. As before, the print quality deteriorated and the printing paper sometimes tore. Similarly, there were similar drawbacks in all voltage widths.

In order to eliminate these drawbacks of the conventional method, it is necessary to reduce the voltage width for determining the level of the print head drive voltage vCc, divide it into multiple parts, and narrow the excitation width of the drive coil according to each voltage level. Just change it. However, in this case, a large number of comparators C and input ports 1 shown in FIG. 1 are required, resulting in an increase in cost.

■ Purpose of the Invention The present invention has been made in response to the above-mentioned circumstances, and an object of the present invention is to provide a printing control method for a dot printer that can obtain high-quality printing by keeping the printing bottle torque approximately constant and can suppress cost increases. do.

(B) Structure and object of the invention According to the present invention, a plurality of printing bins are separated, each printing bin is provided with a printing head provided with a driving coil, and the printing head is driven by driving the printing bins. Changes in the drive voltage are divided into appropriate voltage widths using multiple comparators to determine the level of the drive voltage, and the excitation width of the drive coil of each print bin is changed according to the level of each print head drive voltage. In the print control method of a dot printer, the previous print head applied voltage and the current print head drive voltage are determined at each drive timing of each print bin within the width of each drive voltage level determined by the output of the above comparator. A dot printer O characterized in that, when the current drive voltage is low, the excitation width of the coil is increased, and when the current drive voltage is high, the Iaa width of the drive coil is decreased. This is achieved by providing a printing control method.

6) Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail regarding a dot matrix type printer with reference to the accompanying drawings.

In FIG. 3, the drive coil Ill % Ij2, .
...Ln is provided in each of the O print bins of the print head in which print bins are arranged in a matrix. For example, in the case of 16 pins, 16 drives;
l”x L2 , . . . Ln are provided.

A print head drive voltage "CC" is applied to each of the drive coils L1, L2, . . . , and the drive voltage VCC changes depending on the drive of the print bin.

The change in the print head drive voltage Vcc is divided into appropriate voltage widths and the voltage levels are determined as follows. As shown on the left side in FIG. 3, a plurality of comparators, for example, four comparators C11''Zs...Cnt- are connected in parallel to the print head drive voltage VCC detection section.The comparators C!, C2 are connected in parallel. ,...Cn
The print head driving voltage VCC is applied to the positive voltage of
Verification voltage El with an appropriate voltage difference on the negative side
% Bm,...-En are connected, the value of the driving voltage vcc and the verification voltage E1, E2, ---Bno value are 11, VCC is "Is F" 2, ---g , when it is high, it outputs "11", and when it is low, it outputs l g @.The above respective comparators C1, C2,...
・The output of -Cn is input to CPUK via input port 1, and in this 0CPU, each of the above comparators and parators C1%Cp,
・・・・IAl5B2, depending on the combination of CnO outputs.”
``・'' In 10 voltage ``t'' The level of the drive voltage VCC is determined by the voltage width divided by ``t''.In other words, using four comparators, n1%IAz%Bl s
[When divided into 5 voltage widths using 4O verification voltage, the results are as shown in the following table.

In this way, within each width of the print head drive voltage vcco level, which is roughly divided into appropriate voltage widths, the previous print head body voltage and the current print head body voltage are determined at each print bin drive timing. The print head drive voltage is compared. That is, as shown in the lower left part of FIG.
,......Cn is connected in parallel, and an analog switch 3 is connected in parallel to this comparator Cn-)-t, and a peak hold circuit is further connected to a capacitor t4t-. There is.

Each time a timing pulse P for printing and printing is applied to the analog switch 3, the analog switch 3 is turned on, and the capacitor 4 is charged with the print head driving voltage at that time. That is, the previous print head drive voltage vcc is held in the capacitor 4. Then, when driving the next print bin with the next timing pulse P, the current print head drive voltage vcc is inputted to the positive terminal of the other comparator Cn-1-t, and here! Compared to the pre-excitation drive voltage vcc applied to the negative voltage, when the current drive voltage vcc is low, 101 is output, and when it is high, 101 is output.

The output of the other comparator Cn+t is input to an up/down counter SK. This up-down color
5 is IO'' or 11 of the comparator Cn+t.
Count the number of 1s (for example, down with l□I, up with 'I'') and send the data to the CPU.This CPU reads the data from the up counter S and calculates the current drive. The excitation width of each drive coil L is determined according to the voltage Vcc K, and the timer value of timer 2 is set. Then, when the print information Dl for the first bin is input, the irises game) Gt opens and the first drive starts. Coil L1
is excited for the time of the above excitation width, and the second and subsequent bins are similarly excited and printed.

9 shows the voltage change within one voltage width of the rad drive voltage "CC" and the change in the excitation width of the drive coil■
When illustrated, it becomes as shown in Fig. 4. That is, the excitation width when the power-on maximum voltage is, for example, El, can be calculated by calculation since the print bottle torque Q is constant, and it is set as tl. Here, when the clock CLl of the first bin among the timing pulses P for driving the print bin is input, the first drive coil Ll is excited for a time t2 and the first bin is driven. At this time, the driving voltage Vc
C decreases as shown by the solid line, but when the excitation is cut off, it recovers and begins to rise.

Further, at the timing of the clock CL1, the capacitor 4 shown in FIG. 3 is charged and the driving voltage 81 when driving the first bin is held as shown by the broken line. Next, when the clock CL2 of the second bin is input, the comparator Cn+ta, the above clock CL, compares the input drive voltage El' with the previous drive voltage F21 held in the capacitor 4. , Bl' are lower, so 101t is output. As a result, Ara 1 Da 9 No Kawanta 5 went down, and the CPU took advantage of this ("-"
t') eKZ shift, 1IJa width O increase Δtst
Decision 1:)"1:,1 (Mar2 is set. In other words, the excitation width of the Nibbin's drive coil L2 is (t+Δ1.)
That's it. Similarly, when the clock is CL3, (11+
1. ), and when the clock is CL4, it becomes (1, +Δ13). The clock indicates when the CLB company print data is strong, and at this time the enlarged print head drive voltage continues to rise and recovers to the maximum voltage 'Ei. And in this case, clock C
Since the current driving voltage is higher than the charging voltage of capacitor 4 when L is input, the current driving voltage is higher than that of capacitor 4 when L is input. 5, read this into CPUd, and reduce the excitation width. Therefore, at the next clock CL6, the initial state Kil? ), the excitation width is tl. If you put this all together and make a table, it will look like the next barley.

If the above table is illustrated in the same manner as in Figure 2, it will become as shown in Figure 5. That is, each voltage width Wl-g, , Fi2 to E3, and E3 to E4 of the level of the print head drive voltage is further subdivided, and the excitation width is determined for each drive of each print bin. Print bottle torque Qt - Can be kept approximately constant with a small slope.

Effect of beak Since the present invention has been accomplished as described above, each voltage range of the print head drive voltage level in the print control system of the conventional dot matrix printer is further subdivided and each print bin is controlled in a large state. The excitation width can be determined for each drive, thereby making it possible to keep the printing bottle torque approximately constant.

Therefore, the printing quality can be improved with almost no unevenness in the shading of the printing drum. Furthermore, as is clear from FIG. 5, since the width of the printing bottle torque is small, excessive torque does not occur and does not penetrate the printing paper. Furthermore, since the above-mentioned excessive torque does not occur, power consumption can also be reduced. Furthermore, since only one comparator is required, cost increases can be kept to a minimum.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing the printing control system of a conventional dot matrix printer, Fig. 2 is a chart showing the relationship between the print head drive voltage level, excitation width, and printing bin torque, and Fig. 3 is a dot matrix printer according to the present invention. FIG. 4 is a circuit diagram showing the printing control method of the printer, and a chart showing the state of voltage change and excitation width change within one voltage width of the print head drive voltage, #! FIG. 5 is a chart showing the relationship between the print head drive voltage level, excitation width, and print bottle torque in the present invention. 1...Input boat 2...Timer 3...Analog switch 4...Capacitor S...Up/down Kawanta VCC... Print head drive voltage CI % C2
"'"" cn %OH+1 """'Comparator Ll 1L3, """"' Ln = ... Drive:
y File applicant Fujitsu Limited

Claims (1)

[Claims] It has a plurality of printing bins, each printing bin is provided with a drive coil and has a good printing head, and a plurality of comparators are used to detect changes in the printing head drive voltage caused by driving the printing bins, and adjust the voltage to an appropriate level. In a dot printer print control method in which the level of the drive voltage is determined by dividing the width into two widths, and the excitation width of the drive coil of each print bin is changed according to the level of the drive voltage of each print head, the width is determined based on the output of the comparator. Compare the previous print head drive voltage with the current print head drive voltage at each drive timing of each print bin within the width of each drive voltage level, and if the current drive voltage is low, the line drive coil A dot printer printing control method that increases the excitation width and reduces the excitation width of the drive coil when the current drive voltage is high.