JPH0241280A - Power source voltage detecting system for printer - Google Patents

Abstract

PURPOSE:To detect a power source voltage without influence of the irregularity of a voltage dividing resistor by comparing a measured voltage value read through an A/D converter at the time of monitoring a voltage with a boundary voltage value obtained by multiplying a measured voltage value read at the time of power source ON by a predetermined ratio, and controlling it. CONSTITUTION:A controller 1 identifies a control command from a host system at the time of delivery, and a measured value D0 obtained from the voltage E0 of a power source 7 in this case by an A/D converter 5 through a voltage divider 6 is stored in a nonvolatile memory 2. Then, the controller 1 transmits information to a printer controller 3 if the measured value of the voltage E1 of the power source 7 obtained through the divider 6 and the converter 5 becomes D1 (the value obtained by a formula (1)) or less during a printing operation. The controller 3 controls a printing head driving circuit 4 to divide the following printing operation into twice, and recovers the voltage of the power source 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a power supply voltage detection method for printers, and particularly relates to a power supply voltage detection method for controlling printing operations according to the power supply voltage to reduce the load on the power supply. Detection Method [Prior Art] Conventionally, the power supply voltage detection method for this type of printer divides the power supply voltage and performs control by directly utilizing the value read through an A/D converter.

[Problem to be solved by the invention]

The conventional printer power supply voltage detection method described above does not take into account correction for variations in voltage dividing resistors, and therefore has the disadvantage that highly accurate detection cannot be performed unless highly accurate voltage dividing resistors are used.

[Means to solve the problem]

The present invention monitors the power supply voltage and controls the printing operation to reduce the load on the power supply when the power supply voltage drops.In the power supply voltage detection method of a printer, the power supply voltage is adjusted via an A/D converter when the power is turned on. The boundary voltage is defined as a value obtained by multiplying the measured value read by the A/D converter by a certain ratio, and the control is performed while comparing the measured value read through the A/D converter and the boundary voltage during voltage monitoring. .

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

At the time of shipment, the control unit 1 identifies a switch operation by a worker or a control command from a host device, and converts the voltage Eo of the power supply 7 at that time into a nonvolatile value Do obtained by the A/D converter 5 via the voltage divider circuit 6. Store in memory 2. Next, during the printing operation, the control unit 1 determines that the measured value of the voltage of the power supply 7 obtained through the voltage dividing circuit 6 and the A/D converter 5 is Dl.
(value obtained from equation (3) described later) or less, the information is transmitted to the print control unit 3, and the print control unit 3 instructs the print head drive circuit 4 to control the subsequent printing operation. The voltage of the power source 7 is restored by controlling the power source 7 at different times.

Here, the following relationship holds between the reference voltage Eo of the power supply 7 at the time of shipment, the voltage E1 during the printing operation, the measured value DO of the voltage of the power supply 7 at the time of shipment, and the measured value D1 during the printing operation.

Do = KEo -- (1) Dl = KE, (2) In the above equation, K is a constant including the partial pressure ratio, etc. By eliminating K from equation (1) and equation (2), the following equation is obtained.

That is, in this example, the measured value D1 of the boundary voltage that controls the printing operation to be divided into two steps is determined by the measured values DO, Et, and Eo stored at the time of shipment, and is determined by the variation in the voltage dividing resistor included in the voltage dividing circuit 6. Not affected by

That is, in this embodiment, the reference voltage E is set at the time of shipment.

is memorized for each device, and the voltage of the power supply 7 is the reference voltage E during printing. When the voltage falls below a certain percentage of the voltage E1, it is possible to accurately perform control such as performing subsequent printing operations in two steps and waiting for the power supply to recover.

Next, another embodiment of the present invention will be described. The configuration of the printer is the same as that shown in the block diagram of FIG.

First, when the power is turned on, the control unit 1 reads the voltage of the power supply 7 in the no-load state via the A/D converter 5, and sets the value obtained by multiplying the read measured value by a certain ratio as the boundary voltage to the memory 2.
write to. Next, when the printing operation starts, the control unit 1
monitors the voltage through the A/D converter 5, and if the measured value is lower than the boundary voltage written in the memory 2, the information is transmitted to the print control unit 3, and the print control unit 3 starts driving the print head. The voltage of the power source 7 is restored by controlling the circuit 4, for example, by performing subsequent printing operations separately.

In this embodiment, the voltage of the power supply 7 in the no-load state is E,
The measured value by the A/D converter 5 is 10% from the no-load state.
If the voltage of power supply 7 is El for the boundary voltage that has decreased by %, then E+ = 0.9E.

So, the voltage E! is not affected by the voltage division ratio of the voltage divider circuit.

〔Effect of the invention〕

As explained above, in the present invention, the value obtained by multiplying the measured value obtained through the A/D converter by a certain ratio when a certain constant voltage is applied is set as the boundary voltage, and the measured value output from the A/D converter and the boundary voltage This has the effect of making it possible to detect the power supply voltage without being affected by variations in the voltage dividing resistors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Control unit, 2... Non-volatile memory, 3... Print control unit, 4... Print head drive circuit, 5...・A/D converter, 6...
...Voltage dividing circuit.

Claims (1)

[Claims] The power supply voltage is monitored and when the power supply voltage drops, the printing operation is controlled to reduce the load on the power supply.In the power supply voltage detection method of printers, the power supply voltage is changed to A/A when the power is turned on.
A value obtained by multiplying the measured value read through the D converter by a certain ratio is set as the boundary voltage, and control is performed while comparing the measured value read through the A/D converter and the boundary voltage during voltage monitoring. Power supply voltage detection method for printers.