JPH01281259A - Compensating device for fluctuation in rotational speed of motor used in recorders, etc. - Google Patents

Abstract

PURPOSE:To set recording position with higher precision by measuring carrier speed of recording media with detectors, calculating deviation in the carrier speed in comparison of measured value with the standard value and feeding corrective clock frequency corresponding to the deviation to a record control unit. CONSTITUTION:Detection signals from a detector 4a (when the length of recording media is constant) or the detector 4d and a detector 4b (when the length of recording media is not constant) are given to the control unit 5 of a carrier speed detecting means A, and the carrier speed of recording media is obtained in a value of time at the control unit 5 by a counter 6. A measuring means A transmits the measured values to a deviation calculating means B in which the deviation of carrier speed is calculated by comparing the measured values with the stored standard value. A corrective basic, clock frequency output means C puts out data of the corrective basic clock frequency corresponding to the deviation in the carrier speed to a record control unit 11 by reading it out from a memory unit. And, the control unit 11 sets the data of the corrective basic clock frequency on a timer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for compensating for rotational speed fluctuations due to temperature of a motor in a recording device such as a magnetic encoder or a line printer.

[Prior art and its drawbacks] In recording devices such as magnetic encoders or line printers, it is necessary to keep the conveyance speed of recording media such as magnetic cards and paper constant, so it is difficult to control and stabilize the rotational speed. Servo motors are used.

However, the rotational speed of the servo motor is determined by the electromotive force constant and set input voltage of the tachometer for speed control, but it is also determined by the temperature fluctuation rate of the tachometer, the temperature fluctuation rate such as offset voltage, and the standards that configure the motor drive circuit. Since the resistance value of the voltage Zener diode and resistor changes depending on the motor's heat generation temperature or the environmental temperature, the resistance value of the voltage Zener diode and resistor changes by 0.02 to 0.05% of the servo motor's rotational speed.
``C speed fluctuation occurs.

When a servo motor that does not take any measures against such speed fluctuations is used in a magnetic encoder or line printer's recording medium conveyance device, for example, a displacement occurs in the encode pitch for a magnetic card, and the magnetic card is A reading error may occur during reading, and there may be other inconveniences such as printing outside the predetermined printing field of the pre-printed paper of the line printer.

Conventionally, in order to deal with such fluctuations in the motor's rotational speed due to temperature, a fan was installed to cool the motor, a rotary encoder was installed to detect the motor's rotational speed, and the detected output was fed back to control the motor. This was dealt with by controlling the applied voltage. However, in both cases, the equipment is expensive and the installation space is also difficult, making it difficult to fully meet the demand for high precision recording positions.

[Technical Problems to be Solved] In view of the above points, the present invention provides a detector provided in a recording device or the like to detect the arrival or passage of a recording medium conveyed by a conveyance device driven by a motor. is used to measure the conveyance speed of the recording medium, calculate the deviation in the conveyance speed of the recording medium that reflects the speed fluctuation of the motor based on the measured value and the reference value, and calculate the deviation of the conveyance speed of the recording medium that reflects the speed fluctuation of the motor. By reading out the corresponding basic clock frequency for correction and providing it to the recording control section, it is intended to effectively compensate for fluctuations in rotational speed due to motor temperature with a simple and inexpensive configuration.

[Means for Solving Problems] In order to solve the above-mentioned problems, the motor speed fluctuation compensating device according to the present invention provides the following advantages: means for measuring the conveyance speed of the recording medium using the output of a detector provided to detect the arrival or passage of the medium; (b) a means for storing the measured value obtained by the speed measuring means; (c) means for outputting correction recording clock frequency data corresponding to the deviation given by the deviation calculation means to the recording control section; It is characterized by comprising the following.

[Function] When the recording device is started, the motor rotates, the conveyance device is driven, and the recording medium is conveyed, and the speed measuring means is provided on the conveyance path to detect the arrival, presence, or passage of the recording medium. Using the output from the detector, the conveyance speed of the recording medium is measured.

For this speed measurement, if the length of the recording medium is all constant, one detector can be used and the speed can be measured from the operating time of that detector, but if the length of the recording medium is not constant, , two detectors are provided in the transport direction, and the speed can be measured from the time from the leading edge of the output of the detector of the turner to the leading edge of the output of the latter detector.

The deviation calculating means compares the measured value from the speed measuring means with a stored reference value to calculate the deviation of the conveying speed.

The sleeve correction basic clock frequency output means reads data of the correction basic clock frequency corresponding to the deviation given by the deviation calculation means from the storage section and outputs it to the recording control section.

Therefore, the recording control section sends the data of the basic clock frequency for correction given from the output means to the timer which receives the oscillation frequency from the oscillation section and determines the basic clock for recording. The recording operation is performed using the basic clock frequency.

[Example of this invention] Next, embodiments of the invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration, and FIG. 3 is a flow chart explaining the operation.

A transport device (not shown) that carries a recording medium 3 such as a magnetic card along a transport surface close to a magnetic head 1 of a magnetic recording device and/or a print head 2 of a line printer uses a constant speed control circuit as a power source. 1 servo motor with
Historically used.

The detector 4a is a photoelectric detector consisting of a light-emitting element and a light-receiving element provided opposite to the transport surface of the recording medium, and detects the timing at which the magnetic head 1 starts encoding the recording medium 3 being transported. Recording medium 3 to set
It is numerically provided in order to detect that a recording medium approaches the magnetic head 1 or to detect whether a recording medium is present at a position corresponding to the print head 2.

In the present invention, when the recording medium used is of a certain length, one detector 4a is used to measure the conveyance speed of the recording medium 3. If the recording medium to be used has an undefined length, in addition to the detector 4a, another existing or newly added detector 4b is used to measure the conveyance speed.

That is, the detection signal of the detector 4a or 4a and 4b is given to the control section 5 of the conveyance speed measuring means A constituted by a microcomputer CPU. When only one detector 4a is used, the control unit 5 causes the counter 6 to measure the light blocking time from the output state of that detector, and when two detectors 4a and 4b are used, The counter 6 measures the time from the leading edge of the detection output of the former detector 4a to the leading edge of the detection output of the latter detector 4b to obtain the conveyance speed of the recording medium as a time value.

Based on the end of the shading state or the leading edge of the second detection output,
The conveying speed measuring means A can determine the end of speed measurement, and at the same time, provides the measured value to the deviation calculating means B at the next stage.

The deviation calculation means B stores, as a reference value, a theoretical value or an actual 1 g value of the conveyance speed of the recording medium by the conveyance device at the rotational speed of the servo motor at a steady temperature in the reference value storage unit 7 on a time value basis. There is.

Since the passage time of one detector 4a used when the recording medium has a fixed length can be set to a fixed length for each device, the reference value may be set as a fixed value in advance in an EPROM or the like.

Two detectors 4a if the recording medium has an undefined length.

4b, the distance between the detectors may vary depending on the device. In this case, (a) adjust the transport speed to the standard value for each FI device, (b) count the passing time between the detectors in a measurement circuit and store it in non-volatile memory or set it in a dip switch, etc. This makes it easy to set reference values for each device.

Then, based on the input of the measured value from the conveyance speed measuring means A, the surface difference calculation means B reads out the reference value from the reference value storage section 7, compares it with the measured value in the comparison section 8, and calculates the deviation. is calculated, and the deviation is given to the correcting basic clock frequency output means C at the next stage.

As shown in FIG. 2, the correction basic clock frequency output means C outputs the correction basic clock frequencies (the tally clock frequency cf1 for encoding and the tally clock frequency cfz for printing) corresponding to each deviation value. It is equipped with a frequency table 9 in which data is stored, and when a deviation is given by the deviation calculating means B, the following section 10 of the correcting basic clock frequency output means C converts the deviation into a predetermined address, and the address is used to create a table.・Perform a lookup,
The correction clock frequency data corresponding to the deviation in the transport speed is read out and output to the recording control section 11 .

The recording control unit 11 has an oscillation unit and a timer that counts the frequency from the oscillation unit and outputs a clock signal at a period specified by the set clock frequency data, and outputs the clock signal together with the data to be recorded. The signal is applied to the driver circuit 12 of the recording device. When the correcting clock frequency is given by the correcting basic clock frequency output means C, it is set in the timer to designate the cycle of the encoding basic clock or the printing basic clock, respectively. Therefore, the recording control section creates a basic clock for encoding or printing, and supplies this together with data to the driver circuit 12 of the recording device.

Thereby, the driver circuit 12 drives the magnetic head 1 and/or the print head 2 according to a predetermined clock.
The data is encoded and/or printed on the recording medium 3.

In this way, even if the rotational speed of the motor fluctuates due to the heat generation temperature of the motor and the environmental temperature, and as a result, the conveyance speed of the recording medium changes, the basic clock for magnetic encoding and/or printing on the recording medium remains unchanged. Since the deviation in the conveyance speed is appropriately corrected, the fluctuation in the conveyance speed is compensated for, the recording position accuracy is very high, and the encode pitch and/or printing pitch are also stable.

FIG. 4 shows a paper ticket, which is a recording medium, being conveyed at a predetermined speed.
In an automatic ticket vending machine that encodes required information on the ticket with a magnetic head and prints it with a printer, the present invention compensates for temperature-induced rotational speed fluctuations of the servo motor that drives the device that conveys the ticket. The displacement of the printing position in the case of continuous printing with the device is shown in comparison with the displacement of the printing position in the case of printing without the compensation device as in the past.

The temperature of the data increases and the print length increases depending on the number of tickets issued.The 0-dot line indicates the printing position by an automatic ticket vending machine that does not use a compensation device, and the solid line indicates the printing position by an automatic ticket vending machine equipped with a compensation device. In this case, the number of printed sheets is 2.
When printing 000 sheets, the environmental temperature is 25°C and the motor temperature is 6.
It is 0°C.

As is clear from this figure, in the conventional machine, the printing position shifts within a range of about 2.1 mm even under a nearly constant temperature, but when using the speed fluctuation compensation device according to the present invention, the printing position The displacement is kept within a range of only 0.5 mm. As mentioned above, the variation in the rotational speed of the servo motor due to temperature is 0.02 to 0.05%/'C. Considering changes in environmental temperature, it is extremely difficult for conventional machines to meet the demands for higher density magnetic encoding and higher precision printing position, but according to this invention,
It is understood that this can be easily met.

[Effects of the Invention] As described above, the compensating device for motor rotational speed fluctuation according to the present invention utilizes the detector used for setting the recording start timing for the recording medium, and adjusts the speed of the recording medium. It measures the conveyance speed, obtains the deviation of the conveyance speed from the measured value and a reference value, and outputs a basic clock frequency for correction corresponding to the deviation to the recording control unit, so it requires expensive equipment. It is possible to compensate for variations in motor rotational speed without the need for. Since the basic clock for recording is corrected according to the deviation in the conveyance speed of the recording medium, the correction effect is direct, and the compensation effect is more effective than the method of correction based on the detection of the rotational speed of the motor. Appropriately certain.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a compensation device according to the present invention, FIG. 2 is a schematic diagram showing the storage contents of a frequency table with symbols, FIG. 3 is a flowchart explaining the operation flow of the compensation device, and FIG. The figure is a graph showing the compensation effect in comparison with the conventional example. A... Conveying speed measuring means, B... Deviation calculating means, C... Basic clock frequency output means for correction, 3...
Recording medium, 4a, 4b...detector, 11...recording control unit. Patent applicant: Nippon Signal Co., Ltd. No. 3I-1 Figure 2

Claims (1)

[Claims] In a recording device, etc. that uses a motor as a power source for conveying a recording medium, (a) the output of a detector provided to detect the arrival or passage of the recording medium is used to detect the arrival or passing of the recording medium; means for measuring the conveyance speed; (b) means for calculating a deviation in the conveyance speed by comparing the measured value obtained by the speed measuring means with a stored reference value; and (c) the deviation. A compensating device for motor rotational speed fluctuations, comprising: means for outputting a basic clock frequency for correction corresponding to the deviation given by the calculation means to a recording control section;