JPH0280257A - Printing control method for serial dot printer - Google Patents

Abstract

PURPOSE:To perform divided printing for a definite period and to positively reduce at least a load current by comparing the voltage of a power supply for exciting magnets with preset reference voltage to detect the drop thereof and giving an order for exciting a plurality of the magnets in a divided manner to the control circuit of a printing head. CONSTITUTION:When high density matrix printing is performed in a Z-region, the voltage Vo of a power supply drops to a point P and a detection signal is emitted to a printer main control part from a power supply voltage judge part to be supplied to a printing head control circuit as a divided printing order. Whereupon, the magnets corresponding to 12 upper dot wires (W1-W12) are excited in a printing head 21 and the printing head 21 runs in a direction R1 and only the dot wires W1-W12 are driven to perform the printing of an X-region. After the voltage Vo of the power supply drops to the point P, printing (exciting) operation is stopped for a T-time. Whereupon, the voltage Vo of the power supply rises to be restored and divided printing is performed. When the printing of one line in the X-region is finished, the magnets corresponding to 12 lower dot wires (W13-W24) are excited to perform the one-line printing of a Y-region in a direction L1.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a control method for driving a print head for divisional printing in response to changes in power supply voltage for exciting a magnet in a serial dot printer.

<Prior Art> A serial dot printer uses a plurality of magnets to drive a plurality of corresponding dot wires, thereby printing one character figure using a matrix formed by the dot wires.

In this type of printing drive, when the number of dots printed at the same time increases, that is, when all or most of the dot wires are continuously driven at the same time, the power supply voltage decreases significantly, making it difficult to obtain clear printing quality. If the necessary driving force cannot be obtained, in other words, the effective printing dot density becomes high, and the number of dot wires driven at the same time increases, the average load current increases and the voltage of the magnet decreases accordingly.

If such a situation continues, not only will the printing quality deteriorate, but the magnet coil will also burn out, and ultimately the power may be cut off due to the above-mentioned overload condition.

Therefore, as a means to obtain sufficient driving force even if the power supply voltage decreases, it is conceivable to set the power supply capacity large in advance.

On the other hand, as another means, there is a printer drive method described in Japanese Patent Laid-Open No. 57-160678. This drive method compares the power supply voltage for driving the magnet with a reference voltage, and provides a discrimination section that outputs a lower power supply voltage output. Depending on the output of this discrimination section, the control section controls the magnet during drive. After being deactivated for a predetermined period, the device is controlled to be reactivated, and the deactivation period is sequentially set to be longer in accordance with the decreased output of the determining section again.

<Problems to be Solved by the Invention> Setting the capacity of the power supply voltage to be large as in the previous means is an extremely effective means from the point of view of driving the dot wires, but it is difficult to simultaneously drive all the dot wires continuously for printing. This is rare due to the usability of the printer.
Determining the power supply capacity based on this rare condition will increase the cost of the printer.

Furthermore, in a control method such as the latter method, in which the printing drive is stopped for a predetermined period of time in response to a drop in the power supply voltage, and then printing is started again, there is no deterioration in printing quality, but printing driving and non-printing driving are alternately repeated. Therefore, high-density continuous printing drive requires more printing processing time.

<Means for Solving the Problems> The present invention has been made to solve the above-mentioned conventional problems, and is a serial dot printer equipped with a print head in which a plurality of dot wires are driven by a plurality of magnets. A determination unit is provided that detects a drop in power supply voltage by comparing the power supply voltage for excitation with a preset reference voltage, and issues the detection signal to the printer main control unit. A command is input to the control unit to divide and excite the plurality of magnets and is given to the control circuit of the print head, and by driving the dot wire corresponding to the magnet excited by the command, division printing is performed for a certain period of time. be.

In other words, when the power supply voltage decreases, a detection signal is input to the printer main control section by the first discrimination section, and the print main control section gives a command to the print head control circuit to divide and excite the plurality of magnets. It will be done. In response to the above command, only the required magnets among the plurality of magnets are excited, and the corresponding dot wires are driven to perform divided printing. Therefore, compared to the case where all magnets are excited, at least the load current is reliably reduced. This reduces the drop in power supply voltage, and it is possible to always maintain sufficient driving force to obtain clear print quality without interrupting the printing process.

(Example) Next, an outline of a serial dot printer and a print control method of the present invention will be explained in detail based on the drawings.

FIG. 1 is a control block diagram of a serial dot printer. In the example shown in FIG. 1, 1 is a printer main control section composed of a microprocessor.

It sends print commands and various print data to the print head control circuit 2, and issues space drive commands to the space control circuit 3. 2 is a print head control circuit for exciting a plurality of magnets within the print head 21; Print head 2
1 is a plurality of magnets, for example 24, by excitation of the magnet.
Driving the dot wire of the book, pressing the ink ribbon (not shown) against the paper surface from the back side and printing dots according to the printing command and print data from the printer main control unit 3.
is a space control circuit, which also controls the spacing motor 31 according to the space drive command from the printer main control unit l.
drive. That is, the print head 21 is shown in FIG. 2(a).
The robot is caused to run in the direction R from left to right as shown in (b), and from the right to the left as shown in (b) of the same figure. A power supply unit 4 is a power supply for exciting a plurality of magnets built into the print head 21, and its capacity is set based on the average print dot density during printing. Reference numeral 5 denotes a power supply voltage determination unit, which compares the power supply voltage level for magnet excitation in the power supply unit 4 with a reference voltage previously set based on the voltage level of the non-printable area, and determines the power supply voltage as described later. If the voltage level is low, a detection signal S is sent to the printer main control section l.

In the serial dot printer configured as described above, while the print head 21 travels in the R direction as shown in FIG. 2(a), a predetermined magnet is excited, and the corresponding dot wire is driven to print dots. In this case, if the power supply voltage that excites the magnet is higher than the reference voltage, printing drive is performed continuously in the R direction as in the conventional case. Furthermore, along with the line feed, the print head 21 travels in the L direction to perform printing, as shown in FIG. 2(b). However, all of the magnets are energized and a plurality of dot wires (for example, 24 dot wires W, ~W24, as shown in FIG. 3(a)) are driven simultaneously, as shown in FIG. 3(b).
When high-density matrix printing is performed in the z area as shown in FIG. is decreasing.

This power supply voltage V. The above-mentioned power supply voltage determination section 5 detects a decrease in the power supply voltage. FIG. 5 is a diagram showing the relationship between the drop in power supply voltage and printing drive. In this case, the voltage V that can print the reference voltage Vs
The reference voltage Vs is set to be somewhat higher than n, and the power supply voltage discriminator 5 compares the reference voltage Vs and the power supply voltage vo. Power supply voltage vo
becomes smaller than the reference voltage Vs (point P in Fig. 5, v0
≦Vs) and a detection signal S is input from the power supply voltage determination unit 5 to the printer main control unit l.

In the printer main control unit l, print data is normally written in the RAM of the microprocessor, and after converting this print data into a character pattern, one character pattern data is transferred to the line buffer, and the line buffer is transferred to the microprocessor's RAM. The processor supplies predetermined dot pattern information to the print control circuit 2 to drive the magnet of the print head 21. The microprocessor RAM stores in advance dot pattern information for dividing and driving a plurality of magnets into a predetermined number, and in response to the detection signal S, the dot and pattern information are read out from the RAM and a division printing command is issued. The signal is supplied to the print head control circuit 2 as a signal. When the print head 21 has 24 dot wires, this division print command is issued by dividing the upper 12 dot wires (w I to W1
2) and the lower 12 lines (W13 to W24) are divided and driven for printing. That is, as shown in FIG. 3(b), when printing the dot pattern rAJ, it is printed separately into upper and lower X areas and Y areas.

FIG. 6 is an explanatory diagram of the divided printing operation. When high-density matrix printing is performed in two areas as described above (Fig. 6(a)
)), the power supply voltage v0 drops to point P (see Figure 5),
The detection signal S from the power supply voltage discrimination section 5 is sent to the printer main control section l.
is issued. In the printer main control section 1, dot pattern information written in the RAM of the microprocessor is read out and supplied to the print head control circuit 2 as a division printing command. Then, in the print head 21, the magnets corresponding to the upper 12 dot wires (W, ~W1□) are excited as described above, and the print head 21 runs in the R8 direction as shown in FIG. 6(b), and the dot wire w1 Only %Wtz is driven to print in the X area (see Figure 3), and the power supply voltage is ■. After the value decreases to point P, the printing (excitation) operation is stopped for T time. Then, the power supply voltage Vo rises and recovers until sufficient driving force is obtained, and division printing can be performed.

As shown in FIG. 6(C), when printing for one line in the X area is completed, the magnets corresponding to the printing in the Y area, that is, the lower 12 dot wires (W*: I to W24) are excited, One line of printing is performed in the L1 direction in the same figure (C).

As described above, a line feed is performed after printing one line by dividing into the X area and Y area. When the power supply voltage v0 rises to the voltage Vx (see FIG. 4) that allows clear printing, a signal Sx is sent from the power supply voltage determination unit 5 to the printer main control unit l.
The normal printing drive using 24 dot wires continues as shown in FIG. 5(d). Then again, as described above, multiple dot wires are driven simultaneously to perform high-density matrix printing, and the power supply voltage v0 is at point P (
When the voltage decreases to (VO≦Vs), the detection signal S is generated again, and the same divisional printing as described above is performed.

This makes it possible for the serial dot printer to print continuously while preventing overload of the power supply voltage accompanying printing operations.

Incidentally, in the above embodiment, station division was explained as a division mode, but the single control method is not limited to this, and for example, printing drive using divisions of stations, 3, . . . , 18 is also possible.

<Effects of the Invention> As described above, in this printing control method, the drive of the dot wires is controlled in division during printing operations with high printing dot density, so that overload of the power supply, deterioration of printing quality due to a drop in power supply voltage, and Burnout of the magnet coil can also be prevented.

Furthermore, in situations where continuous high-density printing is required, printing is performed continuously without interrupting the printing operation.
The total printing processing time does not require much time, and the printing control method is suitable for high-density, high-speed printers.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram of a serial dot printer, Fig. 2 is a diagram explaining normal printing operation, Fig. 3 is an explanatory diagram of the division of dot wire and character structure, and Fig. 4 is a diagram showing the effective printing dot density. FIG. 5 is a diagram showing the relationship between power supply voltage and load current. FIG. 5 is a diagram showing the relationship between power supply voltage and divided printing. FIG. 6 is an explanatory diagram of divided printing operation. l...Printer main control unit. 2...Print head control circuit. 3... Space control circuit. 31... Space motor. 5...Power supply voltage determination section. V, ... power supply voltage. 21...Print head. 4...Power supply unit. S...Detection signal. Vs...Reference voltage. Wl~W24-@@dot wire.

Claims (1)

[Claims] In a serial dot printer equipped with a print head that drives a plurality of dot wires by a plurality of magnets, a power supply voltage for exciting the magnets is compared with a preset reference voltage, and A determination unit is provided that detects a drop in power supply voltage and issues a detection signal to the printer main control unit, and when the detection signal is input to the printer main control unit, a command to separately excite the plurality of magnets is sent to control the print head. 1. A printing control method for a serial dot printer, characterized in that divided printing is performed for a certain period of time by driving a dot wire corresponding to the excited magnet applied to a circuit.