JPS6073858A - Control system for printing - Google Patents

Abstract

PURPOSE:To exactly perform printing actions for many dot numbers by a method in which when the voltage of power source for printing is lowered beyond a threshold voltage, the action of the printing head drive circuit is temporarily stopped, and after a fixed time period from a time when the voltage of power source is raised beyond the threshold value, the action of the printing head drive circuit is restarted. CONSTITUTION:When the voltage Vp of power source for printing is lowered beyond a threshold voltage Vth, the action of a printing head 6 is stopped until the voltage Vp is restored to a sufficient level by a control circuit 7. In this case, when the capacity of a condenser 3 to be power source for printing is at a necessary level for printing actions of letters of usual dot numbers, the printing of letters of unusal dot numbers is made without any trouble. In the printing action for many dot numbers of figures, etc., when the voltage Vp is lowered beyond the threshold value Vth, control is made is such as way as to stop the printing action until the voltage Vp is restored to sufficient level. Even when the capacity of the power source for printing is at necessary minimum level, high- duty drive ratios of printing actions for many dot numbers are made possible.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides an I-IJ character power supply in a dot printer.
The present invention relates to the print control method of d), which controls the drive of the print head in accordance with changes in TUC pressure.

[Technical deficiencies in inventions and their problems]

In printers (for example, in-sect printers), characters or graphics are printed using a printing dot matrix. In such a printing operation, the larger the number of dots printed at the same time, the larger the capacity of the printing power source is required. Normally, the number of dots to be printed is from a few to several dozen, but considering the worst case scenario of printing all the dots of the dot matrix in succession, a very large capacity printing power supply is required. There is a need to.

Conventionally, the number of dots during printing has been limited to keep the printing power supply to a relatively small capacity. However, this method has the disadvantage that printing a graphic tube consisting of a large number of dots is restricted, and the printing performance of the dot printer is degraded.

[Purpose of the invention]

The present invention has been made in view of the above problems, and its purpose is to be able to reliably print the number of dots corresponding to the dot pattern to be printed even when the power supply for printing has a relatively small capacity. In this way, it is an object of the present invention to provide a printing control method that can be implemented in a high-performance dot printer.

[Summary of the invention]

In the present invention, the IE voltage detection circuit detects that the printing power supply voltage has fallen below a preset threshold value of 7m voltage necessary for printing operation. Based on the detection result of this voltage detection circuit, the control j circuit is set to 'P' for printing.

When the power supply voltage drops below the threshold voltage, the operation of the print head drive circuit is temporarily interrupted, and furthermore, the control is controlled so that the operation of the print head drive circuit is started a certain period of time after the power supply voltage for printing rises above the threshold voltage. do. As a result, even if the printing power supply has a relatively small capacity and the power supply voltage decreases depending on the number of dots printed, it is possible to print according to the specified number of dots without degrading print quality. Printing operations can be performed.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a printing control system according to an embodiment. In FIG. 1, a rectifying diode Pritsuno circuit 2 rectifies the AC voltage from the AC power supply 1,
Charge capacitor 3. This capacitor 3 smoothes the power supply voltage from the power supply voltage Wj2, and serves as a power supply for driving the print head 6 (power supply for printing). 'The voltage comparator 4 is
The terminal voltage of the capacitor 3 and the power supply voltage Vp for tapping printing are applied to one input terminal, and the threshold voltage vtb, which can also be set in advance by the reference power supply 5, is applied to the other input terminal. This threshold voltage vth is a voltage corresponding to the printing power supply 'fl (voltage Vp) which does not interfere with the normal printing operation of the number of printed dots.The electric IF comparator 4 ``11, pressure Vp?h,
A detection signal S that becomes, for example, "1" when the pressure is smaller than the voltage vth is output to the control circuit 7.

The control circuit 7 includes, for example, a microgrocer, and has a function of outputting a print timing signal PT in response to the detection signal S from the voltage comparator 4. The print timing signal PT from the control circuit 7 is supplied to the base of the transistor 8 of the print head drive circuit. The transistor 8 operates in synchronization with the print timing signal PT, and is configured to drive the print head 6 with the print power supply voltage Vp.

The operation of the print control system configured as described above will be explained. First, when the printer is not performing a printing operation, the full-wave rectified waveform VAC from the AC power supply 1 as shown in FIG. 2 is smoothed and a direct current positive pressure (not shown) corresponding to its peak value is printed. It is supplied to the head 6. By the way, when the print head 6 is driven, the driving power is supplied by the discharge of the charge stored in the capacitor 3 as described above. For this reason, for example, the timings PTI, PT2 of the print timing signal PT as shown in FIG.
When the print head 6 operates in this state, the printing power supply voltage Vp supplied from the capacitor 3 to the print head 6 decreases as shown in FIG. This state of decrease in voltage Vp is
This occurs during the period from when the next cycle of AC voltage VAC is input until the capacitor 3 is charged, and becomes more significant as the number of printed dots increases, that is, as more power is required to be supplied to the print head 6.

When the printing power supply voltage Vp as described above falls below the level of the preset threshold voltage vth, it is detected by the voltage comparator 4 in FIG. At this time, the threshold voltage vth is the lowest voltage value that does not interfere with the normal printing operation of the number of printed dots, as described above.

When the control iI+<+ circuit 7 receives the detection signal S, it stops generating the print timing signal PT necessary for the printing operation. As a result, transistor 8 in FIG. 1 is turned off,
The print head 6 is stopped from operating. When the capacitor 3 is charged and the printing power supply voltage Vp reaches the threshold voltage vth as shown in FIG. 2, the detection signal S of the voltage comparator 4 becomes "0". The control circuit 7 generates a print timing signal (PT3 in FIG. 2) PT after a certain time T from the time when the detection signal S becomes "0", and operates the transoster 8. In this case, the control circuit 7 sends the print timing signal PT3 at a time T for the printing power supply voltage Vp to sufficiently rise to a level equal to or higher than the threshold voltage vth.
is starting to occur.

In this way, the printing power supply voltage Vp is set to the threshold voltage vth
When the power supply voltage Vp for printing decreases further, the control circuit 7 lowers the power supply voltage Vp for printing.
Operation of the print head 6 is discontinued until it has recovered to a sufficient level. In this case, if the capacitance of the capacitor 3 serving as the printing power supply is sufficient for printing characters with a normal number of dots, printing of characters with a normal number of dots can be performed without any problem. In a printing operation that involves a large number of dots such as figures (that is, when the drive duty ratio of the print head 6 is larger than normal), when the printing power supply voltage Vp decreases and reaches the threshold voltage Vth, printing occurs as described above. Power supply voltage Vp
The printing operation is controlled so that the printing operation is stopped when the level has recovered to a sufficient level. Therefore, even in the case of the minimum necessary printing power supply capacity, printing operation with a large number of dots and a high drive duty ratio is possible. Note that, as mentioned above, printing operations involving a large number of dots are generally a small proportion of the total printing operations, so even if the printing operations are temporarily stopped, the printing efficiency does not decrease significantly.

In the above embodiment, a case has been described in which the printing power supply voltage Vp decreases in a printing operation in which a large number of dots such as figures are printed. However, the present invention is not limited to this, and even if the input AC voltage vAc temporarily decreases for other reasons,
The same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described in detail above, according to the present invention, even when the printing power source is relatively small, printing operations with a large number of dots can be performed reliably. Therefore, it is possible to eliminate limitations on the printing operation, that is, the drive duty ratio of the print head, due to the power supply capacity for printing. Therefore, the printing operation of the number of dots corresponding to the number of dots and e-coons to be printed can be reliably realized even with a small power supply. Furthermore, even in the event of an abnormality such as a temporary drop in the input power supply voltage, printing can be performed reliably without adversely affecting printing quality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a printing control system according to an embodiment of the present invention, and FIG. 2 explains the operation of FIG. 1.
FIG. 1... AC 1st section source, 2... Rectifier diode Pritsuno circuit, 3... Capacitor, 4... Voltage comparator, 6...
-Print head, 7...control circuit.

Claims (1)

[Claims] A print head drive circuit that drives the print head with a predetermined printing power supply voltage, a voltage detection circuit that detects that the printing power supply voltage has fallen below a preset threshold voltage necessary for printing operation, and this voltage detection circuit. If the power supply voltage for printing falls below the threshold voltage based on the detection result of the circuit, the operation of the print head drive circuit is temporarily interrupted, and the power supply voltage for printing falls below the threshold voltage after a certain period of time from the time when the power supply voltage for printing rises above the threshold voltage. 1. A print control method comprising: control means for controlling the print head drive circuit to start operation.