JP3371968B2 - Printer and printer control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method using an AD converter and a microprocessor in a printer.

[0002]

2. Description of the Related Art In order to drive a printer mechanism with high accuracy and at high speed and maintain good printing quality, it is preferable that the power supply voltage for driving a motor and a print head is constant. In many printers, the power consumption of the motor and the print head during printing operation is not constant, and particularly in the case of the print head, the power consumption is greatly affected by the operation pattern. The change in power consumption changes the drive power supply voltage, affects the torque of the motor and the operation of the print head, and causes deterioration of print quality.

Therefore, the drive power supply voltage is monitored and the motor drive current setting is changed or the energization time of the print head is changed according to the voltage change to prevent the deterioration of the print quality due to the change of the drive power supply voltage. Control methods are often used. These controls are performed by a microprocessor, and an AD converter is usually used as a means for serving as a sensor for notifying the microprocessor of a drive voltage.

The voltage detection by the AD converter is performed by detecting the initial deviation of the voltage dividing resistor for converting the printer mechanism driving voltage into the measurable voltage range of the AD converter, the initial deviation of the AD converter, the initial deviation of the reference power supply voltage, and the respective temperatures. Measurement errors occur due to characteristics and aging. Generally, the initial deviation of electric parts is 1000 times or more larger than the temperature change and the secular change. Therefore, in order to prevent the deterioration of the voltage measurement accuracy due to the initial deviation of the voltage dividing resistor, the initial deviation of the AD converter, and the initial deviation of the reference power supply voltage, the following method has been conventionally used.

The first method is a method that uses highly accurate electric components (small initial deviation). Specifically, a voltage divider resistor is configured using a high-precision resistor with a small initial deviation, a reference power source is configured with a high-precision stabilized power supply element with a small initial deviation, and a high-precision resistor with a small initial deviation is used. The AD converter is used.

The second method is to adjust the division ratio of the voltage dividing resistor or the reference power source voltage value by using a semi-fixed resistor to obtain the initial deviation of the voltage dividing resistor, the initial deviation of the AD converter and the initial value of the reference power source voltage. This is a method of canceling the deviation.

[0007]

The effect of such a method is sufficient and can contribute to the improvement of the voltage detection accuracy in the printer.

However, in the case of the first method, adjustment after printer manufacturing is unnecessary, but since many high-precision electric parts are used, the parts cost becomes very expensive, and voltage measurement As for accuracy, since the worst values of the initial deviations of a plurality of parts are superposed, the target measurement accuracy may not be achieved even if existing ultra-high accuracy electric parts are combined.

In the case of the second method, the initial deviation of the voltage dividing resistance,
Although it is possible to cancel the initial deviation of the AD converter and the initial deviation of the reference power supply voltage, in order to adjust the division ratio of the voltage dividing resistor or the reference power supply voltage value using the semi-fixed resistor, the voltage at the time of shipment of the device is adjusted. While measuring, adjust the semi-fixed resistor to a certain voltage value by using a special jig and apply a fixative, or operate the semi-fixed resistor while measuring the resistance and fix it to a certain resistance value. It complicates the work such as applying the agent. And the semi-fixed resistance changes with temperature,
It is a component that is vulnerable to changes in humidity and vibration, and can cause a significant decrease in the reliability of the equipment.

The present invention solves such a problem, and an object of the present invention is to control a printer mechanism inexpensively, at high speed and with high precision in a printer having an AD converter and a microprocessor. To provide.

[0011]

A printer of the present invention includes an AD converter which receives a drive power supply voltage for driving a print head or the like, receives a reference voltage, and outputs a digital conversion value of the drive power supply voltage. , A parameter serving as a basis for producing a voltage correction table having characteristics for respectively correcting the plurality of different digital conversion values so as to reduce an error included in each of the plurality of different digital conversion values from the AD converter. To remember
And a parameter of the non-volatile storage means.
Voltage correction table to create a voltage correction table based on
Cable production program and the voltage correction table production program
Temporarily change the voltage correction table created by
A RAM for storing the inputs the digital conversion value of the AD converter, by using the voltage correction table in the RAM is stored, a voltage correction means for correcting the digital conversion value, composed of a microprocessor or the like It is,
The digital conversion value corrected by the voltage correction means
It characterized the this <br/> to have a control circuit for controlling the print head or the like group.

The reference power supply for supplying the reference voltage to the AD converter is the same as the power supply for operating the control circuit.

[0013]

Further, the above-mentioned parameter is characterized in that a voltage whose voltage value is known in advance is given to the AD converter as a drive voltage, and is calculated or adjusted from the output digital conversion value and the known voltage.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a relevant portion of the configuration of a printer in an embodiment of the voltage detecting method of the present invention.

A CPU connected by a bus (119) and its peripherals (105), a ROM (109), and a RAM (11
The control computer portion formed by 0) is provided for controlling the entire printer, and the operations related to the voltage detection of the present invention are only a part of the control functions. CPU and its periphery (105) and ROM (10
9), the control computer portion formed by the RAM (110) normally operates by the program stored in the ROM (109). When an external test program ROM (107) connectable to the bus (119) is connected by the connecting means (122), it can also be operated by the program stored in the test program ROM (107). Test program ROM (10
When 7) is connected, the external ROM is connected to the program switching means (131) through the external ROM connection signal (132).
Of the presence of the program, and means for switching programs (131)
Has a test program ROM (107) outside,
A chip select signal is generated to preferentially access the external ROM. By switching the chip select signal, the internal ROM (109) is disabled, the external test program ROM (107) is enabled, and the CPU switches the control program.

CPU and its periphery (105) and ROM
An EEPROM (117) is connected to (109) and holds information that needs to be stored even when the power of the device is turned off. This EEPROM (117) does not exist as one of the constituent elements only for the voltage correction function, but rather has the main function of storing the control parameters and default values of the printer. It is also used to store parameters for The printer control parameters and default values are the timer value for adjusting the print position so that it does not shift depending on the direction in which the print head moves, the font type selected when the power is turned on, the character table, and the international character set. , Data for determining interface settings and the like.

An AD converter (102) is connected to a CPU (105) in order to convert a voltage value which is an analog signal into a digital signal and notify the computer portion. A CPU developed for controlling a printer often has an AD converter built in a chip of the CPU. In the present invention, it does not matter whether the AD converter is in the CPU or not, and it can be realized in either case. The AD converter (102) needs a reference voltage in order to convert the voltage into a digital signal, and the signal line for supplying the reference voltage is the reference voltage input (101). In this embodiment, the reference power source is not specially provided and also serves as a power source (+ 5v) for operating the logic circuit such as the CPU. Normally, the reference power source of the AD converter is not the same as the power source for operating the logic circuit but is generally composed of a high-precision regulator and exists independently. However, the error correction method according to the present invention is used. Thus, since the initial deviation of the absolute value of the voltage of the reference power source does not matter, it can also serve as a power source for operating the logic circuit, which greatly contributes to cost reduction. However,
It is not preferable that the power supply as the reference voltage fluctuates due to temperature changes, aging changes, and the like. However, even in the regulator that constitutes the power supply for operating the logic circuit, the voltage fluctuation thereof is smaller than the initial deviation of the absolute value of the reference power supply voltage constituted by the high-accuracy regulator, and the voltage detection accuracy in the printer can be improved. Sufficient to implement using an error correction scheme.

The measured voltage is the voltage of the driving power source (103) of the printer mechanism, the print head, etc., which is connected to the control circuit by the connecting means (121) and is also supplied to the voltage dividing resistor (118). When the voltage of the driving power source (103) is not limited to be within the input allowable voltage range of the AD converter (102), the voltage dividing resistor (118) is set to A.
It serves to extend the measurement voltage range of the D converter (102). The voltage range is AD through the voltage dividing resistor (118)
The measured voltage converted into the input allowable voltage range of the converter (102) is given to the AD converter (102), converted into a digital signal by comparison with the reference voltage input (101), and recognized by the CPU (105). .

The features of the printer configuration in the embodiment of the voltage detecting method of the present invention are that the test program means stored as a test program ROM (107) outside the printer is present, and the control is performed by detecting that the program is connected. Exists in the printer and a control program ROM (10
9), a voltage correction table creation program for creating a data conversion table for correcting the voltage measurement value, which is stored together with the printer power-on, and the timing of voltage detection during printer operation, of the AD converter. This is the existence of a voltage correction program for obtaining the corrected voltage value by subtracting the data conversion table from the output value.

FIG. 2 is a diagram showing conversion characteristics of the AD conversion means of the printer in the embodiment of the voltage detection method of the present invention. The horizontal axis represents the measured input voltage (306), and the vertical axis represents the total AD conversion result (301) of the AD conversion means including the voltage dividing resistance and the reference voltage.

The actual AD conversion characteristic with respect to the ideal AD conversion characteristic (308) is an error due to the initial deviation of the voltage dividing resistor, the initial deviation of the AD converter, the initial deviation of the reference voltage, the respective temperature characteristics, and the secular change. AD that includes the upper limit of the error
There are variations from the conversion characteristic (307) to the AD conversion characteristic (309) including the lower limit of the error. As a result, a certain measured voltage (305) becomes
Conversion error 1 (302) or conversion error 2 (304) occurs.

FIG. 3 is a diagram showing a method of correcting the AD conversion means of the printer in the embodiment of the voltage detecting method of the present invention. The measured voltage (410) has a conversion characteristic (4) including an error.
07), the ideal AD conversion value (406) is output from the AD converter as an AD conversion value (405) including an error and is notified to the CPU.

CPU and its peripheral circuits, ROM, RA
The computer part composed of M has an AD including an error.
A correction table for correcting the conversion value (405) to an AD conversion value that does not include an error, that is, a true value is provided, and the AD conversion value (4
05) is converted into the corrected measurement result (412).

The parameter which is the basis of this correction table characteristic (403) is the program switching means using the test program stored in the test program ROM outside the printer by using the test reference voltage power supply as the measured voltage at the time of manufacturing the printer. Is generated when it is executed by the action of, and is stored in the EEPROM which is a non-volatile storage means. E using the correction table characteristics (403) as a table
Since the capacity becomes large when stored in the EPROM, the correction table characteristic (403) is approximated to a mathematical expression, and the parameter is stored in the EEPROM. In the case of this embodiment, since the correction table characteristic (403) is expressed by a straight line (linear expression), the parameter stored in the EEPROM is generally the point where the straight line slope and the straight line intersects the X or Y axis. However, as will be described later, in this case, only the inclination value is sufficient.

The characteristic stored as a parameter is read out from the EEPROM when the printer is powered on by a voltage correction table preparation program stored in the printer together with the printer control program, and is used for correcting the voltage measurement value. The data conversion table on the RAM showing the table characteristics (403) can be recreated. The timing at which the voltage is detected during printer operation can be checked by checking the print head drive voltage at each print timing or every fixed time, detecting the legal voltage at the start of printing, measuring the current value when driving the motor, and measuring the voltage for setting the drive cycle. is there.
Particularly important is control for guaranteeing the operation of the print head even when the drive voltage changes by changing the print head drive pulse width depending on the print head drive voltage. In the case of such an application, it is necessary to determine the voltage at high speed and further reduce the processing time of the CPU as much as possible so as not to reduce the throughput of the printer. Therefore, at the timing when voltage detection is performed during printer operation, a voltage correction program that operates to obtain a corrected voltage value by subtracting the data conversion table created on the RAM from the output value of the AD converter when the power is turned on is operated. By doing so, complicated correction calculation at the time of voltage measurement is omitted, and high-speed processing only by referring to the numerical table becomes possible.

By correcting and recognizing the output value of the AD converter in this way, the initial deviation of the voltage dividing resistance, AD
The voltage measurement error caused by the initial deviation of the converter and the initial deviation of the reference voltage can be reduced to zero. Most of the voltage measurement errors are caused by these variations, and other errors due to temperature changes and aging are on the PPM order. Compared with errors due to resistance deviation of several%, it is 1/1000 to 1/10000. is there. Therefore,
By eliminating the error caused by the initial deviation of the voltage dividing resistor, the AD converter, and the reference voltage, the voltage detection accuracy is dramatically improved. A control program stored inside the printer is provided by providing a test program means stored outside the printer device and used for adjustment, and a program switching means for detecting the connection of the test program means and transferring control to the test program means. Voltage correction table creation program that creates a data conversion table for correcting the voltage measurement value that is used when the printer is powered on, without significantly increasing the capacity of the AD converter, and the output value of the AD converter that is used at the timing of voltage detection. By having a voltage correction program for obtaining a corrected voltage value by subtracting the data conversion table from, the speed can be increased.

FIG. 4 is a flow chart showing the test program operation during printer adjustment in the embodiment of the voltage detection method of the present invention. A test program is used for adjustment, but as described above, the test program is stored in the dedicated test program ROM, and when it is connected to the bus through the connecting means, the adjustment operation starts (501).

At the time of adjustment, it is necessary to use an accurate test reference power source whose voltage has been calibrated as a drive power source. First, the test reference power source is connected as the measured voltage (50).
2). In this state, AD conversion is performed (503) and the value is read (509). An AD converter normally exhibits a linear characteristic that is 0 V with respect to the voltage and is proportional to the voltage passing through the conversion value 0. When the correction is performed, it is sufficient to perform the correction on the slope of the straight line. Therefore, the input voltage change rate of the conversion value, that is, the slope of the conversion characteristic line is calculated (504), and the value of the slope is stored in the EEPROM. It is stored (508). If the correction is not sufficient with the slope of the conversion characteristic, it is possible to change the voltage of the test reference voltage power supply, obtain the correction curve from the AD conversion value for each, and store the parameters describing the curve. is there.

FIG. 5 is a flow chart showing the operation during initialization after power-on of the printer in the embodiment of the voltage detecting method of the present invention. After the power is turned on, the printer performs an initialization operation in accordance with a normal control program, in which an operation of creating a correction table of AD conversion values is performed (601).

When correcting the conversion characteristic with a straight line, A
The slope of the D conversion characteristic line is read from the EEPROM (6
02). Then, a conversion table of AD conversion value to voltage obtained from a straight line of the slope of the reciprocal of the value read from the EEPROM, which passes the conversion value 0 at 0 V, is prepared in the RAM (60).
3). As a result, it is possible to easily and quickly correct the AD conversion value without the need for time-consuming division when measuring the voltage.

FIG. 6 is a flow chart showing the operation at the time of measuring the voltage of the printer in the embodiment of the voltage detecting method of the present invention. When the voltage measurement timing comes during the printer operation (701), AD conversion is performed (702), and the AD conversion value is read (703). After that, the voltage value corresponding to the read AD conversion value is obtained by looking up the conversion table of AD conversion value to voltage value created on the RAM (70).
4) (705). Here, since the error correction is performed at the same time, an accurate voltage value can be obtained without complicated calculation.

[0033]

As described above, according to the present invention, it is possible to provide a high-speed, high-printing-quality printer device at low cost in a printer that controls while monitoring the drive power supply voltage of the printer mechanism, the print head, and the like. effective.

[Brief description of drawings]

FIG. 1 is a block diagram showing a relevant portion of a configuration of a printer in an embodiment of a voltage detection method of the present invention.

FIG. 2 is a diagram showing conversion characteristics of the AD conversion means of the printer in the embodiment of the voltage detection method of the present invention.

FIG. 3 is a diagram showing a method of correcting the AD conversion means of the printer in the embodiment of the voltage detection method of the present invention.

FIG. 4 is a flowchart showing a test program operation during printer adjustment in the embodiment of the voltage detecting method of the present invention.

FIG. 5 is a flowchart showing an operation during initialization after power-on of the printer in the embodiment of the voltage detection method of the present invention.

FIG. 6 is a flow chart showing the operation of the printer during voltage measurement in the embodiment of the voltage detection method of the present invention.

[Explanation of symbols]

102 AD converter 107 test program ROM 120 test reference power supply

Continuation of front page (56) Reference JP-A-3-96371 (JP, A) JP-A-3-222995 (JP, A) JP-A-2-29371 (JP, A) JP-A-4-113860 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 29/46 B41J 29/38

Claims (8)

(57) [Claims] 1. A drive power source for driving a print head or the like.
The source voltage is input, the reference voltage is given,
An AD converter that outputs a digital conversion value of the voltage, Multiple different digital conversion values from the AD converter
To reduce the error contained in
The characteristics for correcting different digital conversion values
Voltage correction tableThe base parameters for making
Non-volatile storage means for storing data, Based on the parameters of the non-volatile storage means, voltage correction
Voltage correction table making program for making cables
And Created by the voltage correction table creation program
RAM for temporarily storing the voltage correction table
When, The digital conversion value of the AD converter is input,The above
RAM storesUsing the voltage correction table,
Voltage correction means for correcting the digital conversion value, Consists of a microprocessor, etc., The voltage correction means
Based on the digital conversion value corrected by
ControlWith control circuitDoCharacterized by
Linta. 2. Prior to producing the voltage correction table,
A voltage whose voltage value is known in advance is used as the drive voltage.
The digital conversion value output to the D converter and output
Based on the known voltage
Adjusts the parameters stored in the non-volatile storage means
The calculated or adjusted parameters as described above.
Further has a test program stored in the spontaneous storage means
The printer according to claim 1, wherein: 3. The test program includes the parameters
Is the slope of the straight line as the voltage correction table.
If the voltage correction is not enough for the slope,
By changing the known voltage, change each of the changed voltages.
The curve is obtained from the digital conversion value corresponding to
3. The printer according to claim 2 , wherein the characteristic is a parameter . 4. A reference voltage is supplied to the AD converter.
The reference power source is the same as the power source for operating the control circuit.
The printer according to claim 1, wherein the printer is one. 5. The printer according to claim 1 , wherein the process of creating the voltage correction table by the voltage correction table creating program and storing the voltage correction table in the RAM is performed when the power is turned on. 6. A drive power source for driving a print head or the like.
Input the source voltage to the AD converter and set the reference voltage to the AD
The digital conversion value of the drive power supply voltage given to the converter
To obtain Multiple different digital conversion values from the AD converter
To reduce the error contained in
The characteristics for correcting different digital conversion values
Voltage correction tableThe base parameters for making
Storing the data in a non-volatile storage medium, Using the parameters stored in the non-volatile storage medium
To create a voltage correction table, and
Temporarily storing in RAM, Using the digital conversion value of the AD converter as an input,
Using the voltage correction table stored in RAM, The above
Step of correcting digital conversion value from AD converter
When, A print head or the like based on the corrected digital conversion value
And the process of controllingDoOf the printer characterized by
Control method. 7. Prior to producing the voltage correction table,
A voltage whose voltage value is known in advance is used as the drive voltage.
The digital conversion value output to the D converter and output
Based on the known voltage
Adjusts the parameters stored in the non-volatile storage means
The calculated or adjusted parameters as described above.
Characterized by further comprising a step of storing in the spontaneous storage means.
The method of the printer according to claim 6. 8. The voltage correction table is produced and the
The step of storing in RAM should be performed when the power is turned on.
7. The method of controlling a printer according to claim 6, wherein.